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Sample records for switchable light-input light-output

  1. A switchable light-input, light-output system modelled and constructed in yeast

    Directory of Open Access Journals (Sweden)

    Kozma-Bognar Laszlo

    2009-09-01

    Full Text Available Abstract Background Advances in synthetic biology will require spatio-temporal regulation of biological processes in heterologous host cells. We develop a light-switchable, two-hybrid interaction in yeast, based upon the Arabidopsis proteins PHYTOCHROME A and FAR-RED ELONGATED HYPOCOTYL 1-LIKE. Light input to this regulatory module allows dynamic control of a light-emitting LUCIFERASE reporter gene, which we detect by real-time imaging of yeast colonies on solid media. Results The reversible activation of the phytochrome by red light, and its inactivation by far-red light, is retained. We use this quantitative readout to construct a mathematical model that matches the system's behaviour and predicts the molecular targets for future manipulation. Conclusion Our model, methods and materials together constitute a novel system for a eukaryotic host with the potential to convert a dynamic pattern of light input into a predictable gene expression response. This system could be applied for the regulation of genetic networks - both known and synthetic.

  2. The light output of BGO crystals

    International Nuclear Information System (INIS)

    Gong Zhufang; Ma Wengan; Lin Zhirong; Wang Zhaomin; Xu Zhizong; Fan Yangmei

    1987-01-01

    The dependence of light output on the surface treatment of BGO crystals has been tested. The results of experiments and Monte Carlo calculation indicate that for a tapered BGO crystal the best way to improve the uniformity and the energy resolution and to obtain higher light output is roughing the surface coupled to photomultiplier tube. The authors also observed that different wrapping method can effect its uniformity and resolutoin. Monte Carlo calculation indicates that the higher one of the 'double peaks' is the photoelectron peak of γ rays

  3. Light output optimization from various geometries of BGO crystals

    International Nuclear Information System (INIS)

    Anderson, S.; Salomon, M.

    1982-11-01

    The different geometrical effects that determine the light output of BGO crystals are investigated. Several bulk shapes, attenuation lengths and reflectors are compared. The highest light output is obtained from trapezoids with specular reflecting walls

  4. Switchable capacitor

    NARCIS (Netherlands)

    Rottenberg, X.; Jansen, Henricus V.; Tilmans, H.A.C.; De Raedt, W.

    2003-01-01

    A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom elecrode, a dielaectric layer deposited on at least part of sai bottum electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to the

  5. Switchable capacitor

    NARCIS (Netherlands)

    Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, H.A.C.; Tilmans, Hendrikus; De Raedt, Walter

    2011-01-01

    A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom elecrode, a dielaectric layer deposited on at least part of sai bottum electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to the

  6. Effect of Aspect Ratio on the Light Output of Scintillators

    CERN Document Server

    Pauwels, Kristof; Gundacker, S.; Knapitsch, A.; Lecoq, P.

    2012-01-01

    The influence of the geometry of the scintillators is presented in this paper. We focus on the effect of narrowing down the section of crystals that have a given length. The light output of a set of crystals with very similar scintillating properties but different geometries measured with several coupling/wrapping configurations is provided. We observe that crystals shaped in thin rods have a lower light output as compared to bulk or sliced crystals. The effect of unpolishing the crystal faces is also investigated, and it is shown that highest light outputs are not necessarily obtained with crystals having all faces polished. Simulation results based on a realistic model of the crystal that implements light scattering on the crystal edges are in agreement with the experimental data. Fine-tuning of this model would allow us to further explore the details of light propagation in scintillators and would be highly valuable to fast timing detection and highly granular detectors.

  7. Light output from six battery operated dental curing lights

    International Nuclear Information System (INIS)

    Shimokawa, Carlos Alberto Kenji; Turbino, Míriam Lacalle; Harlow, Jessie Eudora; Price, Hannah Louise; Price, Richard Bengt

    2016-01-01

    Light Curing Units (LCUs) are used daily in almost every dental office to photocure resins, but because the light is so bright, the user is unable to tell visually if there are any differences between different LCUs. This study evaluated the light output from six dental LCUs: Elipar Deep Cure-S (3M ESPE), Bluephase G2 (Ivoclar Vivadent), Translux 2Wave (Heraeus Kulzer), Optilight Prime (Gnatus), Slim Blast (First Medica) and Led.B (Guilin Woodpecker) with a fully charged battery, after 50, and again after 100, 20 second light exposures. For each situation, the radiant power was measured 10 times with a laboratory-grade power meter. Then, the emission spectrum was measured using a fiber-optic spectrometer followed by an analysis of the light beam profile. It was found there were significant differences in the LCU power and the irradiance values between the LCUs (p < 0.01). The Optilight Prime and Slim Blast LCUs showed a significant reduction in light output after a 50 and 100 exposures, while Bluephase G2 exhibited a significant reduction only after 100 exposures (p < 0.01). The Bluephase G2 and Translux 2 Wave delivered an emission spectrum that had two distinct wavelength emission peaks. Only the Elipar Deep Cure-S and Bluephase G2 LCUs displayed homogeneous light beam profiles, the other LCUs exhibited highly non-homogeneous light beam profiles. It was concluded that contemporary LCUs could have very different light output characteristics. Both manufacturers and researchers should provide more information about the light output from LCUs. - Highlights: • The six LCUs delivered significantly different light output characteristics. • The use of a single irradiance value does not adequately describe the light output from a curing light. • Small differences in the tip area, or how it is defined, will have a large effect on the calculated irradiance. • In some cases there were large portions of the light tip that emitted less than 400 mW/cm². • The radiant

  8. Light output from six battery operated dental curing lights.

    Science.gov (United States)

    Shimokawa, Carlos Alberto Kenji; Turbino, Míriam Lacalle; Harlow, Jessie Eudora; Price, Hannah Louise; Price, Richard Bengt

    2016-12-01

    Light Curing Units (LCUs) are used daily in almost every dental office to photocure resins, but because the light is so bright, the user is unable to tell visually if there are any differences between different LCUs. This study evaluated the light output from six dental LCUs: Elipar Deep Cure-S (3M ESPE), Bluephase G2 (Ivoclar Vivadent), Translux 2Wave (Heraeus Kulzer), Optilight Prime (Gnatus), Slim Blast (First Medica) and Led.B (Guilin Woodpecker) with a fully charged battery, after 50, and again after 100, 20second light exposures. For each situation, the radiant power was measured 10 times with a laboratory-grade power meter. Then, the emission spectrum was measured using a fiber-optic spectrometer followed by an analysis of the light beam profile. It was found there were significant differences in the LCU power and the irradiance values between the LCUs (p<0.01). The Optilight Prime and Slim Blast LCUs showed a significant reduction in light output after a 50 and 100 exposures, while Bluephase G2 exhibited a significant reduction only after 100 exposures (p<0.01). The Bluephase G2 and Translux 2Wave delivered an emission spectrum that had two distinct wavelength emission peaks. Only the Elipar Deep Cure-S and Bluephase G2 LCUs displayed homogeneous light beam profiles, the other LCUs exhibited highly non-homogeneous light beam profiles. It was concluded that contemporary LCUs could have very different light output characteristics. Both manufacturers and researchers should provide more information about the light output from LCUs. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. A general theory for ball lightning structure and light output

    Science.gov (United States)

    Morrow, R.

    2018-03-01

    A general theory for free-floating ball lightning is presented which unifies the phantom plasma ball theory involving the production of very little light, with theories for ball lightning involving light output produced by burning particles from the soil. The mechanism for the formation of plasma balls is shown to be quite general, producing very similar plasma balls independent of initial ion densities over four orders of magnitude. All that is required is an excess of positive ions in the initial ball of ions. The central plasma density after 1 s is shown to be the reciprocal of the ion neutralization coefficient for all cases, both analytically and computationally. Further, the plasma region has zero electric field in all cases. Surrounding the plasma ball is a sphere of positive ions moving away from the centre via their own space-charge field; this space-charge field, which is the same in all cases near the plasma ball, drives negative ions and negative particles towards the plasma centre. The connection with burning particle theories is the proposition that the burning particles are highly-charged which is very likely after a lightning strike. Burning negatively charged particles would be driven into the plasma ball region and trapped while any positively charged particles would be driven away. The plasma ball structure is shown to last more than 10 s and the ‘burnout time’ for a typical coal particle (as an example) has been measured at 5–10 s this is comparable with the lifetimes observed for ball lightning. The light output from a few hundred particles is estimated to be ~1 W, a typical output for ball lightning. Finally, suggestions are made for the generation of ball lightning in the laboratory.

  10. Intrinsic energy resolution and light output of the $Lu_{07}Y_{03}$ AP:Ce scintillator

    CERN Document Server

    Kuntner, C; Auffray, Etiennette; Lecoq, P; Pizzolotto, C; Schneegans, M

    2002-01-01

    Light output and energy resolution for a 2*2*10 mm/sup 3/ LuYAP:Ce crystal coupled to a XP2020Q photomultiplier were studied. The measured light output of 8530 photons/MeV includes the correction for the quantum efficiency of the XP2020Q photomultiplier. An energy resolution of 7.33% was obtained for 662 keV gamma -rays with a long face coupled to the PMT. The measured number of 2130 phe/MeV implies a photoelectron statistical contribution of 6.59% and hence a LuYAP intrinsic energy resolution of 3.21%. The relative light output of the LuYAP scintillator measured for photon energies varying from 31 keV to 1.333 MeV was constant within 7%. These observations are consistent with results for the YAP:Ce scintillator, and with the assumption that there is a direct correlation between the energy resolution of scintillators and non-proportionality of their light output versus energy in the low-energy domain. The results are compared to the relative light output of the LSO:Ce scintillator measured for varying energie...

  11. Light output distribution in scintillator strips with wave length shifting fibers of DANSS spectrometer

    Science.gov (United States)

    Pogorelov, N.; Aleksev, I.; Kalinkin, D.; Makhichkulyan, I.; Nesterov, V.; Rusinov, V.; Starostin, A.; Svirida, D.; Tarkovsky, E.

    2017-12-01

    DANSS is a highly segmented plastic scintillator detector, which uses scintillator strips with a Gd-loaded reflective cover to detect reactor antineutrino by inverse beta-decay. Light is collected with wave length shifting fibers (3 per strip) placed in grooves. Therefore the distribution of light output could be significantly non-uniform. Transverse profile of light output was studied in ITEP at a test bench consisting of proportional chambers and scintillator strips. Tracks of cosmic particles, which crossed chambers, were reconstructed with high accuracy, whereby transverse profiles of light output were built with step 1 mm for six scintillator strips. This result is important for calibration of DANSS and the method could be useful in constructing similar detectors.

  12. Evaluation of neutron light output response functions in EJ-309 organic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Norsworthy, Mark A., E-mail: marknors@umich.edu; Poitrasson-Rivière, Alexis, E-mail: alexispr@umich.edu; Ruch, Marc L., E-mail: mruch@umich.edu; Clarke, Shaun D., E-mail: clarkesd@umich.edu; Pozzi, Sara A., E-mail: pozzisa@umich.edu

    2017-01-11

    An accurate model of the nonlinear detector response of organic scintillators to neutrons is required to correctly simulate fast neutron detection, as well as interpret measured pulse height data. Several empirical and semi-empirical models are available to fit measured scintillator light output data. In this work, EJ-309 light output data from neutrons depositing 1.15–5.15 MeV on hydrogen were analyzed using empirical models as well as semi-empirical models based on the work of Birks and Voltz. Although all tested models fit the experimental light output data well in the measured range, the models were observed to diverge in low-energy extrapolation. The models were then tested by comparing a measurement and MCNPX-PoliMi simulation of an EJ-309 detector response to fast neutrons from a {sup 252}Cf spontaneous fission source. The agreement between the measured and simulated pulse height distributions varied significantly depending on the light output model used. The best agreement between simulated and measured neutron pulse height distributions was achieved by using the Birks model. The bin-by-bin agreement was better than 5% over the range 0.08–2.18 MeVee, and better than 10% from 2.18 to 3.13 MeVee. The integral count rate over the range 0.08–3.14 MeVee differed by less than 1% in absolute units. - Highlights: • Various models exist for neutron light output in organic scintillators. • Models fit data well, but behave differently in extrapolation to low-energy. • The choice of light output model profoundly affects simulated detector response. • Birks' Law yields the best agreement of simulation and experiment.

  13. Two-phase cooling of light emitting diode for higher light output and increased efficiency

    NARCIS (Netherlands)

    Ye, H.; Mihailovic, M.; Wong, C.K.Y.; Zeijl, H.W. van; Gielen, A.W.J.; Zhang, G.Q.; Sarro, P.M.

    2013-01-01

    High Power Light Emitting Diode (HP LED) is one of the promising candidates for future lighting systems with efficient energy consumption. However, around 70% of the input power will be still transferred to heat. Recently, to obtain more light output, the increased electrical currents consequently

  14. Characterising the light output from Argon bombs by two simultaneous diagnostic techniques

    CSIR Research Space (South Africa)

    Olivier, M

    2013-01-01

    Full Text Available The light output from Argon-bombs was investigated by means of ultra high speed photography (Cordin Model 550-32 camera) and locally developed photodiode sensors. Tubes of various sizes were inflated with Argon gas, and were detonated on one side...

  15. Switchable Bragg gratings

    DEFF Research Database (Denmark)

    Marckmann, Carl Johan

    2003-01-01

    Research Center (MIC) at the Technical University of Denmark. The Bragg gratings were fabricated at COM using UV irradiation of the planar waveguides using the phase mask method. The induction of a frozen-in DC electric field into the samples was performed by thermal poling of the Bragg gratings...... layers, it becam possible to investigate the symmetry properties of the third-order nonlinearities. Contrary to the expectations for an amorphous material, the measurements indicated an almost polarization independent third-order nonlinearity - the most probable explanation being electrostriction......The subject of this ph.d. thesis was the development of an electrically switchable Bragg grating made in an optical waveguide using thermal poling to be applied within optical telecommunication systems. The planar waveguides used in this thesis were fabricated at the Micro- and Nanotechnology...

  16. Neutron light output response and resolution functions in EJ-309 liquid scintillation detectors

    Science.gov (United States)

    Enqvist, Andreas; Lawrence, Christopher C.; Wieger, Brian M.; Pozzi, Sara A.; Massey, Thomas N.

    2013-07-01

    Neutron light output response functions and detector resolution functions were measured at Ohio University's tandem Van de Graaff generator for three cylindrical EJ-309 liquid scintillator cells, having dimensions 12.7(∅)-by-12.7, 7.6-by-7.6, and 7.6-by-5.1 cm. A 7.44 MeV deuteron beam was used on an 27Al target generating a continuous spectrum over the energy range from a few hundred keV to over 10 MeV. The light output response functions are determined using an exponential fit. Detector resolution functions are obtained for the 12.7-by-12.7 and 7.6-by-7.6 cm detectors. It is demonstrated that the dependence on detector size is important for the light output response functions, but not to the same extent for the resolution function, even when photomultiplier tubes, detector material, and other detector characteristics are carefully matched.

  17. Neutron light output response and resolution functions in EJ-309 liquid scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Enqvist, Andreas, E-mail: enqvist@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor 48109 (United States); Lawrence, Christopher C., E-mail: cclawr@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor 48109 (United States); Wieger, Brian M., E-mail: brianmwi@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor 48109 (United States); Pozzi, Sara A., E-mail: pozzisa@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor 48109 (United States); Massey, Thomas N., E-mail: massey@ohio.edu [Institute of Nuclear and Particle Physics, Ohio University, Athens, OH 45701 (United States)

    2013-07-01

    Neutron light output response functions and detector resolution functions were measured at Ohio University's tandem Van de Graaff generator for three cylindrical EJ-309 liquid scintillator cells, having dimensions 12.7(∅)-by-12.7, 7.6-by-7.6, and 7.6-by-5.1 cm. A 7.44 MeV deuteron beam was used on an {sup 27}Al target generating a continuous spectrum over the energy range from a few hundred keV to over 10 MeV. The light output response functions are determined using an exponential fit. Detector resolution functions are obtained for the 12.7-by-12.7 and 7.6-by-7.6 cm detectors. It is demonstrated that the dependence on detector size is important for the light output response functions, but not to the same extent for the resolution function, even when photomultiplier tubes, detector material, and other detector characteristics are carefully matched.

  18. Construction of a test stand for the measurement of the light output uniformity of CALIFA crystals

    Energy Technology Data Exchange (ETDEWEB)

    Susenburger, Markus; Ignatov, Alexander; Kroell, Thorsten [Technische Universitaet Darmstadt, Darmstadt (Germany)

    2016-07-01

    Currently, the Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is under construction. One experiment at GSI and FAIR is called Reactions with Relativistic Radioactive Beams (R{sup 3}B). A key component of the R{sup 3}B is the CALorimeter for In Flight detection of γ-rays and light charged pArticles (CALIFA), which will surround the R{sup 3}B target chamber and will be capable of the detection of γ-rays in a wide energy range from 100 keV to 30 MeV as well as of light charged particles. CALIFA is built out of two parts, the so called CALIFA barrel and CALIFA endcap. The barrel consists of 1952 CsI(Tl) detector crystals which have to fulfill several specifications. One of these specifications is the uniformity of the light output. Depending on the location of the deposited energy, the crystal's light output varies due to optical focusing effects. This behavior can be manipulated by lapping the crystal's surface. The aim of this work is the development of a test stand which will check if the crystals match the requirements according to the light output uniformity. Because of the large number of crystals needed to be tested, the stand automates the test procedure, which guarantees comparable test measurement for all crystals. The development and construction of this stand is reported.

  19. Simulated and measured neutron/gamma light output distribution for poly-energetic neutron/gamma sources

    Science.gov (United States)

    Hosseini, S. A.; Zangian, M.; Aghabozorgi, S.

    2018-03-01

    In the present paper, the light output distribution due to poly-energetic neutron/gamma (neutron or gamma) source was calculated using the developed MCNPX-ESUT-PE (MCNPX-Energy engineering of Sharif University of Technology-Poly Energetic version) computational code. The simulation of light output distribution includes the modeling of the particle transport, the calculation of scintillation photons induced by charged particles, simulation of the scintillation photon transport and considering the light resolution obtained from the experiment. The developed computational code is able to simulate the light output distribution due to any neutron/gamma source. In the experimental step of the present study, the neutron-gamma discrimination based on the light output distribution was performed using the zero crossing method. As a case study, 241Am-9Be source was considered and the simulated and measured neutron/gamma light output distributions were compared. There is an acceptable agreement between the discriminated neutron/gamma light output distributions obtained from the simulation and experiment.

  20. Switchable lasing in multimode microcavities

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei V.; Chigrin, Dmitry N.; Lavrinenko, Andrei

    2007-01-01

    We propose the new concept of a switchable multimode microlaser. As a generic, realistic model of a multimode microresonator a system of two coupled defects in a two-dimensional photonic crystal is considered. We demonstrate theoretically that lasing of the cavity into one selected resonator mode...... in terms of the laser bistability is presented....

  1. Stacked switchable element and diode combination with a low breakdown switchable element

    Science.gov (United States)

    Wang, Qi [Littleton, CO; Ward, James Scott [Englewood, CO; Hu, Jian [Englewood, CO; Branz, Howard M [Boulder, CO

    2012-06-19

    A device (10) comprises a semiconductor diode (12) and a switchable element (14) positioned in stacked adjacent relationship. The semiconductor diode (12) and the switchable element (14) are electrically connected in series with one another. The switchable element (14) is switchable from a low-conductance state to a high-conductance state in response to the application of a low-density forming current and/or a low voltage.

  2. Solid polystyrene and deuterated polystyrene light output response to fast neutrons

    Science.gov (United States)

    Simpson, R.; Danly, C.; Glebov, V. Yu.; Hurlbut, C.; Merrill, F. E.; Volegov, P. L.; Wilde, C.

    2016-04-01

    The Neutron Imaging System has proven to be an important diagnostic in studying DT implosion characteristics at the National Ignition Facility. The current system depends on a polystyrene scintillating fiber array, which detects fusion neutrons born in the DT hotspot as well as neutrons that have scattered to lower energies in the surrounding cold fuel. Increasing neutron yields at NIF, as well as a desire to resolve three-dimensional information about the fuel assembly, have provided the impetus to build and install two additional next-generation neutron imaging systems. We are currently investigating a novel neutron imaging system that will utilize a deuterated polystyrene (CD) fiber array instead of standard hydrogen-based polystyrene (CH). Studies of deuterated xylene or deuterated benzene liquid scintillator show an improvement in imaging resolution by a factor of two [L. Disdier et al., Rev. Sci. Instrum. 75, 2134 (2004)], but also a reduction in light output [V. Bildstein et al., Nucl. Instrum. Methods Phys. Res., Sect. A 729, 188 (2013); M. I. Ojaruega, Ph.D. thesis, University of Michigan, 2009; M. T. Febbraro, Ph.D. thesis, University of Michigan, 2014] as compared to standard plastic. Tests of the relative light output of deuterated polystyrene and standard polystyrene were completed using 14 MeV fusion neutrons generated through implosions of deuterium-tritium filled capsules at the OMEGA laser facility. In addition, we collected data of the relative response of these two scintillators to a wide energy range of neutrons (1-800 MeV) at the Weapons Neutrons Research Facility. Results of these measurements are presented.

  3. Solid polystyrene and deuterated polystyrene light output response to fast neutrons.

    Science.gov (United States)

    Simpson, R; Danly, C; Glebov, V Yu; Hurlbut, C; Merrill, F E; Volegov, P L; Wilde, C

    2016-04-01

    The Neutron Imaging System has proven to be an important diagnostic in studying DT implosion characteristics at the National Ignition Facility. The current system depends on a polystyrene scintillating fiber array, which detects fusion neutrons born in the DT hotspot as well as neutrons that have scattered to lower energies in the surrounding cold fuel. Increasing neutron yields at NIF, as well as a desire to resolve three-dimensional information about the fuel assembly, have provided the impetus to build and install two additional next-generation neutron imaging systems. We are currently investigating a novel neutron imaging system that will utilize a deuterated polystyrene (CD) fiber array instead of standard hydrogen-based polystyrene (CH). Studies of deuterated xylene or deuterated benzene liquid scintillator show an improvement in imaging resolution by a factor of two [L. Disdier et al., Rev. Sci. Instrum. 75, 2134 (2004)], but also a reduction in light output [V. Bildstein et al., Nucl. Instrum. Methods Phys. Res., Sect. A 729, 188 (2013); M. I. Ojaruega, Ph.D. thesis, University of Michigan, 2009; M. T. Febbraro, Ph.D. thesis, University of Michigan, 2014] as compared to standard plastic. Tests of the relative light output of deuterated polystyrene and standard polystyrene were completed using 14 MeV fusion neutrons generated through implosions of deuterium-tritium filled capsules at the OMEGA laser facility. In addition, we collected data of the relative response of these two scintillators to a wide energy range of neutrons (1-800 MeV) at the Weapons Neutrons Research Facility. Results of these measurements are presented.

  4. Solid polystyrene and deuterated polystyrene light output response to fast neutrons

    International Nuclear Information System (INIS)

    Simpson, R.; Danly, C.; Merrill, F. E.; Volegov, P. L.; Wilde, C.; Glebov, V. Yu.; Hurlbut, C.

    2016-01-01

    The Neutron Imaging System has proven to be an important diagnostic in studying DT implosion characteristics at the National Ignition Facility. The current system depends on a polystyrene scintillating fiber array, which detects fusion neutrons born in the DT hotspot as well as neutrons that have scattered to lower energies in the surrounding cold fuel. Increasing neutron yields at NIF, as well as a desire to resolve three-dimensional information about the fuel assembly, have provided the impetus to build and install two additional next-generation neutron imaging systems. We are currently investigating a novel neutron imaging system that will utilize a deuterated polystyrene (CD) fiber array instead of standard hydrogen-based polystyrene (CH). Studies of deuterated xylene or deuterated benzene liquid scintillator show an improvement in imaging resolution by a factor of two [L. Disdier et al., Rev. Sci. Instrum. 75, 2134 (2004)], but also a reduction in light output [V. Bildstein et al., Nucl. Instrum. Methods Phys. Res., Sect. A 729, 188 (2013); M. I. Ojaruega, Ph.D. thesis, University of Michigan, 2009; M. T. Febbraro, Ph.D. thesis, University of Michigan, 2014] as compared to standard plastic. Tests of the relative light output of deuterated polystyrene and standard polystyrene were completed using 14 MeV fusion neutrons generated through implosions of deuterium-tritium filled capsules at the OMEGA laser facility. In addition, we collected data of the relative response of these two scintillators to a wide energy range of neutrons (1-800 MeV) at the Weapons Neutrons Research Facility. Results of these measurements are presented.

  5. Heat Transfer Manipulation via Switchable Wettability Surfaces

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed research seeks to manipulate heat transfer during flow condensation in low-gravity environments by employing switchable wettability surfaces....

  6. Switchable Hydrophobic-Hydrophilic Surfaces

    CERN Document Server

    Bunker, B C; Huber, D L; Kent, M S; Kushmerick, J G; Lopez, G P; Manginell, R P; Méndez, S E; Yim, H

    2002-01-01

    Tethered films of poly n-isopropylacrylamide (PNIPAM) films have been developed as materials that can be used to switch the chemistry of a surface in response to thermal activation. In water, PNIPAM exhibits a thermally-activated phase transition that is accompanied by significant changes in polymer volume, water contact angle, and protein adsorption characteristics. New synthesis routes have been developed to prepare PNIPAM films via in-situ polymerization on self-assembled monolayers. Swelling transitions in tethered films have been characterized using a wide range of techniques including surface plasmon resonance, attenuated total reflectance infrared spectroscopy, interfacial force microscopy, neutron reflectivity, and theoretical modeling. PNIPAM films have been deployed in integrated microfluidic systems. Switchable PNIPAM films have been investigated for a range of fluidic applications including fluid pumping via surface energy switching and switchable protein traps for pre-concentrating and separating...

  7. Light-output enhancement of GaN-based vertical light-emitting diodes using periodic and conical nanopillar structures.

    Science.gov (United States)

    Kim, Su Jin; Kim, Kyeong Heon; Chung, Ho Young; Shin, Hee Woong; Lee, Byeong Ryong; Jeong, Tak; Park, Hyung Jo; Kim, Tae Geun

    2014-06-15

    We investigated GaN-based vertical light-emitting diodes (VLEDs) with periodic and conical nanopillar arrays (CNAs) to improve the light-output efficiency. We found that a 470 nm diameter and 0.8-0.9 μm height increased the light output, and the devices suffered no significant electrical property degradations. The light-output power was 272% and 5.1% greater than flat- and rough-surface VLEDs at 350 mA, respectively. These improved optical properties are attributed to the optimized CNAs, which increase the effective photon escape cone and reduce the total internal reflection at the n-GaN-air interface. We also investigated the emission characteristics and mechanisms with finite-difference time-domain simulations.

  8. Effects of Photonic Crystals on the Light Output of Heavy Inorganic Scintillators

    CERN Document Server

    Knapitsch, Arno; Fabjan, Christian W; Leclercq, Jean-Louis; Letartre, Xavier; Mazurczyk, Radoslaw; Lecoq, Paul

    2013-01-01

    Photonic crystals (PhCs) are optical materials which can affect the propagation of light in multiple ways. In recent years PhCs contributed to major technological developments in the field of semiconductor lasers, light emitting diodes and photovoltaic applications. In our case we are investigating the capabilities of photonic crystal slabs with the aim to improve the performance of heavy inorganic scintillators. To study the combination of scintillators and PhCs we use a Monte-Carlo program to simulate the light propagation inside a scintillator and a rigorous coupled wave analysis (RCWA) framework to analyse the optical PhC properties. The simulations show light output improvements of a wide range of scintillating materials due to light scattering effects of the PhC slabs. First samples have been produced on top of 1.2 × 2.6 × 5 mm LSO (cerium-doped Lutetium Oxyorthosilicate, Lu_2SiO_5:Ce^3+) scintillators using electron beam lithography and reactive ion etching (RIE). Our samples show a 30-60% light outp...

  9. The nonlinear light output of NaI(Tl) detectors in the Modular Total Absorption Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Rasco, B.C., E-mail: crasco@lsu.edu [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Fijałkowska, A.; Karny, M. [Faculty of Physics, University of Warsaw, Pasteura 5, PL-02093 Warszawa (Poland); Rykaczewski, K.P. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wolińska-Cichocka, M. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Oak Ridge Associated Universities, Oak Ridge, TN 37831 (United States); Heavy Ion Laboratory, University of Warsaw, Warsaw PL-02-093 (Poland); Grzywacz, R.; Goetz, K.C. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37966 (United States)

    2015-07-11

    A new detector array, the Modular Total Absorption Spectrometer (MTAS), was commissioned at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Lab (ORNL). Total absorption gamma spectra measured with MTAS are expected to improve beta-feeding patterns and beta strength functions in fission products. MTAS is constructed out of hexagonal NaI(Tl) detectors with a unique central module surrounded by 18 identical crystals assembled in three rings. The total NaI(Tl) mass of MTAS is over 1000 kg. The response of the central and other 18 MTAS modules to γ-radiation was simulated using the GEANT4 toolkit modified to analyze the nonlinear light output of NaI(Tl). A detailed description of the GEANT4 modifications made is discussed. Simulated energy resolution of MTAS modules is found to agree well with the measurements for single γ transitions of 662 keV ({sup 137}Cs) with 8.2% full width half maximum (FWHM), 835 keV ({sup 54}Mn) with FWHM of 7.5% FWHM, and 1115 keV ({sup 65}Zn) with FWHM of 6.5%. Simulations of single and multiple γ-rays from {sup 60}Co are also discussed.

  10. Photo-switchable membrane and method

    Science.gov (United States)

    Marshall, Kenneth L; Glowacki, Eric

    2013-05-07

    Switchable gas permeation membranes in which a photo-switchable low-molecular-weight liquid crystalline (LC) material acts as the active element, and a method of making such membranes. Different LC eutectic mixtures were doped with mesogenic azo dyes and infused into track-etched porous membranes with regular cylindrical pores. Photo-induced isothermal phase changes in the imbibed mesogenic material afforded large, reversible changes in the permeability of the photo-switchable membrane to nitrogen. For example, membranes imbibed with a photo-switchable cyanobiphenyl LC material demonstrated low permeability in the nematic state, while the photo-generated isotropic state demonstrated a 16.times.-greater sorption coefficient. Both states obey a high linear sorption behavior in accordance with Henry's Law. In contrast, membranes imbibed with a photo-switchable phenyl benzoate LC material showed the opposite permeability behavior to the biphenyl-imbibed membrane, along with nonlinear sorption behavior.

  11. Switchable bio-inspired adhesives

    Science.gov (United States)

    Kroner, Elmar

    2015-03-01

    Geckos have astonishing climbing abilities. They can adhere to almost any surface and can run on walls and even stick to ceilings. The extraordinary adhesion performance is caused by a combination of a complex surface pattern on their toes and the biomechanics of its movement. These biological dry adhesives have been intensely investigated during recent years because of the unique combination of adhesive properties. They provide high adhesion, allow for easy detachment, can be removed residue-free, and have self-cleaning properties. Many aspects have been successfully mimicked, leading to artificial, bio-inspired, patterned dry adhesives, and were addressed and in some aspects they even outperform the adhesion capabilities of geckos. However, designing artificial patterned adhesion systems with switchable adhesion remains a big challenge; the gecko's adhesion system is based on a complex hierarchical surface structure and on advanced biomechanics, which are both difficult to mimic. In this paper, two approaches are presented to achieve switchable adhesion. The first approach is based on a patterned polydimethylsiloxane (PDMS) polymer, where adhesion can be switched on and off by applying a low and a high compressive preload. The switch in adhesion is caused by a reversible mechanical instability of the adhesive silicone structures. The second approach is based on a composite material consisting of a Nickel- Titanium (NiTi) shape memory alloy and a patterned adhesive PDMS layer. The NiTi alloy is trained to change its surface topography as a function of temperature, which results in a change of the contact area and of alignment of the adhesive pattern towards a substrate, leading to switchable adhesion. These examples show that the unique properties of bio-inspired adhesives can be greatly improved by new concepts such as mechanical instability or by the use of active materials which react to external stimuli.

  12. Safer Battery with Switchable Polymer Coating Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to utilize a switchable polymer (SWP) to prevent catastrophic failure due to internal shorting or overdischarge in lithium-ion...

  13. Theoretical analysis of enhanced light output from a GaN light emitting diode with an embedded photonic crystal

    International Nuclear Information System (INIS)

    Wen Feng; Liu Deming; Huang Lirong

    2010-01-01

    The enhancement of the light output of an embedded photonic crystal light emitting diode is investigated based on the finite-difference time-domain modeling. The embedded photonic crystal (PC) lattice type, multi-layer embedded PC, distance between the multiple quantum well and the embedded PC are studied. It is found that the embedded one dimensional PC can act as well as embedded two dimensional PCs. The emitted light flux in the up direction can be increased by a new kind of multi-layer embedded PC. Also, we show that the light output in the up direction for the LED with both surfaces and embedded PC could be as high as five times that of a conventional LED. (semiconductor devices)

  14. Light output and response function of an NE-213 scintillator to neutrons up to 100 MeV

    International Nuclear Information System (INIS)

    Uwamino, Y.; Shin, K.; Fujii, M.; Nakamura, T.

    1982-01-01

    Light output of the NE-213 organic scintillator to 22.6, 27.6 and 48.7 MeV protons were obtained by the analysis of recoil proton spectra by monoenergetic neutron injection into the scintillator. The neutrons were generated by the proton bombardment on a thin lithium target backed with a thick carbon beam stopper. The measured light outputs were slightly smaller than the extrapolation of other works. Birks' semiempirical formula was fitted to these measured data and our previous experimental data of 11.03, 9.01 and 8.05 MeV protons and the formula failed to fit them completely over this wide energy region. A Monte Carlo code to calculate response functions of an NE-213 scintillator was improved by, 1) using these measured light output data, 2) using new cross sections of ENDF/B-IV, O5S and Guerra's compiled data, and 3) replacing the evaporation model of the C(n, p), C(n, pn) and C(n, 2n) reactions with the two-body reaction model. Results of this revised Monte Carlo calculation generally agreed well with the measured response functions of other works. Response functions of a 7.62-cm-diameter by 7.62-cm-long NE-213 scintillator to neutrons of energies up to 100 MeV were calculated by this Monte Carlo code. (orig.)

  15. Valuation of switchable tariff for wind energy

    International Nuclear Information System (INIS)

    Yu, Wang; Sheble, Gerald B.; Lopes, Joao A. Pecas; Matos, Manuel Antonio

    2006-01-01

    The current fixed tariff remuneration for wind energy is not compatible with the deregulation of the electric power industry. The time-varying and location-dependent value of renewable energy is not acknowledged. The newly announced switchable tariff for wind energy in the Spanish electricity market provides a promising solution to compensating renewable energy within the deregulated electric power industry. The new switchable tariff provides wind generators more flexibility in operating wind generation assets. Such flexibilities provide option value in coordinating the seasonality of wind energy, demand on electric power and electricity prices movement. This paper models and valuates the flexibility on switching tariff as real compound options for wind generators. Numerical examples valuate wind generation assets under fixed tariff, spot market price taking, and yearly and monthly switchable tariffs. The optimal switching strategies are identified. The impacts of the switchable tariff on sitting criteria and values of wind generation assets are investigated. An improvement on the yearly switchable tariff is suggested to further reduce the operation risk of wind generators and fully explore the efficiency provided by competitive electricity markets. (author)

  16. Light output due to cosmic-ray muons for an EJ301 scintillator of 12.7 cm in diameter and length

    Science.gov (United States)

    Kajimoto, Tsuyoshi; Tanaka, Kenichi; Endo, Satoru; Hamano, Tsuyoshi; Takada, Masashi

    2018-02-01

    The light output due to cosmic-ray muons was determined for an EJ301 scintillator of 12.7 cm in diameter and length. Muons were measured with the setup of the EJ301 scintillator put between two thin plastic scintillators. Coincidence analysis using the signals from these plastic scintillators revealed a broad peak in the distribution of the EJ301 scintillator as measured with a charge-integrating analog-to-digital converter (ADC). The mode of the distribution was obtained by fitting analysis. To convert the corresponding ADC value into light output, continuous-energy protons were measured, with a resulting light output of the mode became to be 20.5 ± 1.0 MeVee. By measuring cosmic-ray muons with this setup, we have shown that we can obtain a calibration point in the higher light output region.

  17. Light-output response of the plastic scintillator for the Mars Science Laboratory (MSL) Radiation Assessment Detector (RAD)

    Science.gov (United States)

    Martin, C.; Boehm, E.; Kortmann, O.; Boettcher, S.; Wimmer-Schweingruber, R. F.; Burmeister, S.; Ehresmann, B.; Hassler, D. M.; Zeitlin, C.; Posner, A.; Neal, K.; Rafkin, S.; Weigle, E.; Reitz, G.

    2008-12-01

    The Radiation Assessment Detector (RAD) onboard NASA's Mars Science Laboratory (MSL) rover mission has been designed to detect a wide range of particle types (charged and neutral) and energies on the Mars surface. The BC432m plastic scintillator coupled to PIN photodiodes has been used as a neutron detector as well as an anticoincidence shield for the RAD instrument. We present an experimental study of the non-linear light-output response of the BC432m for protons and neutrons beams. The experimental results have been compared to the parametric formula based on the theoretical work of Birks and Chou. Furthermore, a comparison between the quenching effect found in the BC432m and in other inorganic scintillators (CsI:Tl) used in the RAD instrument has been performed.

  18. Measurements of the proton light output function of the organic liquid scintillator NE213 in several detectors

    CERN Document Server

    Hawkes, N P; Bond, D S; Croft, S; Jarvis, O N; Watkins, N

    2002-01-01

    When using an organic liquid scintillator such as NE213 for neutron spectrometry, the light output as a function of proton energy is needed in order to unfold the neutron spectrum from the scintillator's pulse height distribution. We have measured this function for several detectors over the range 1.5-16 MeV approximately, using monoenergetic neutrons from the Harwell 5 MV Van de Graaff accelerator. Results were obtained for a wide variety of sizes and shapes of the scintillator cell, and were found to be essentially in agreement within errors. The results were also compared with those of several other workers (amongst whom there is considerable disagreement). Below 10 MeV, there is excellent agreement with one worker and moderate or poor agreement with others; above 10 MeV, agreement is moderate in all cases. We conclude that workers wishing to unfold neutron spectra from NE213 pulse height distributions would be advised to make measurements with their own particular detector configuration, rather than use p...

  19. Stability of the Light Output, Oral Cavity Tip Accessibility in Posterior Region and Emission Spectrum of Light-Curing Units.

    Science.gov (United States)

    André, C B; Nima, G; Sebold, M; Giannini, M; Price, R B

    2018-04-09

    This study evaluated the light output from six light-emitting diode dental curing lights after 25 consecutive light exposures without recharging the battery, tip accessibility in the posterior region, and light beam spread from light-curing units. Irradiance, spectral peak, and radiant exposure were measured with the battery fully charged (Bluephase Style, ESPE Cordless, Elipar S10, Demi Ultra, Valo Cordless, and Radii-Cal) and monitored for 25 light exposures (each lasting 10 seconds). The tip diameter was measured to identify the beam size and the ability of the six light-curing units to irradiate all areas of the lower second molar in the standard output setting. Four curing lights delivered a single peak wavelength from 454 to 462 nm, and two (Bluephase Style and Valo Cordless) delivered multiple emission peaks (at 410 and 458 nm and 400, 450, and 460 nm, respectively). The irradiance and radiant exposure always decreased after 25 exposures by 2% to 8%, depending on the light unit; however, only ESPE Cordless, Valo Cordless, and Radii-Cal presented a statistical difference between the first and the last exposure. The tip diameter ranged from 6.77 mm to 9.40 mm. The Radii-Cal delivered the lowest radiant exposure and irradiance. This light was also unable to access all the teeth with the tip parallel to the occlusal surface of the tooth. Not all of the blue-emitting lights deliver the same emission spectra, and some curing lights delivered a lower irradiance (as much as 8% lower) after the 25th exposure.

  20. Wavelength switchable fiber-optic Sagnac filter

    Science.gov (United States)

    Su, Dan; Qiao, Xueguang; Rong, Qiangzhou; Shao, Zhihua

    2018-03-01

    A wavelength switchable fiber-optic comb filter based on an in-line Sagnac interference is proposed and demonstrated. The proposed filter consists of a polarizer, two polarization controllers (PCs) and two sections of polarization maintaining fiber (PMFs). The output comb spectrum characteristics of the configuration are theoretically analyzed by Jones matrix, and then numerically simulated and experimentally demonstrated, of which the results present four comb filter-types (sinusoidal, flat-top and narrow-band superposition, and line-shaped spectra) by adjusting the polarizations of light with PCs.

  1. Passband switchable microwave photonic multiband filter.

    Science.gov (United States)

    Ge, Jia; Fok, Mable P

    2015-11-02

    A reconfigurable microwave photonic (MWP) multiband filter with selectable and switchable passbands is proposed and experimentally demonstrated, with a maximum of 12 simultaneous passbands evenly distributed from 0 to 10 GHz. The scheme is based on the generation of tunable optical comb lines using a two-stage Lyot loop filter, such that various filter tap spacings and spectral combinations are obtained for the configuration of the MWP filter. Through polarization state adjustment inside the Lyot loop filter, an optical frequency comb with 12 different comb spacings is achieved, which corresponds to a MWP filter with 12 selectable passbands. Center frequencies of the filter passbands are switchable, while the number of simultaneous passbands is tunable from 1 to 12. Furthermore, the MWP multiband filter can either work as an all-block, single-band or multiband filter with various passband combinations, which provide exceptional operation flexibility. All the passbands have over 30 dB sidelobe suppression and 3-dB bandwidth of 200 MHz, providing good filter selectivity.

  2. Crystal growth and temperature dependence of light output of Ce-doped (Gd, La, Y)2Si2O7 single crystals

    Science.gov (United States)

    Horiai, Takahiko; Kurosawa, Shunsuke; Murakami, Rikito; Shoji, Yasuhiro; Pejchal, Jan; Yamaji, Akihiro; Ohashi, Yuji; Kamada, Kei; Yokota, Yuui; Ishizu, Tomohiro; Ohishi, Yasuo; Nakaya, Taisuke; Yoshikawa, Akira

    2018-03-01

    Ce-doped (Gd, La)2Si2O7 scintillation crystals are expected to be used as gamma-ray detectors for high temperature measurement. To realize scintillators for high temperature environment, we investigated (Ce0.01 Gd0.59-x La0.40 Yx)2Si2O7 (x = 0.00, 0.05, 0.10, 0.15) single crystals grown by the micro-pulling-down method. The results showed that a 5% Y-admixed Ce-doped (Gd, La)2Si2O7 scintillator can yield higher light output when compared with Y-free Ce-doped (Gd, La)2Si2O7 scintillator. The light outputs at 25°C and 175°C were determined to be ∼43,000 and ∼40,000 photons/MeV, respectively. Moreover, 1 inch size 5% Y-admixed Ce-doped (Gd, La)2Si2O7 scintillator was grown by the Czochralski technique, and its light output at 175°C kept the value of around 95% of the value at 25°C.

  3. Enhanced Light Output of Dipole Source in GaN-Based Nanorod Light-Emitting Diodes by Silver Localized Surface Plasmon

    Directory of Open Access Journals (Sweden)

    Huamao Huang

    2014-01-01

    Full Text Available The light output of dipole source in three types of light-emitting diodes (LEDs, including the conventional planar LED, the nanorod LED, and the localized surface plasmon (LSP assisted LED by inserting silver nanoparticles in the gaps between nanorods, was studied by use of two-dimensional finite difference time domain method. The height of nanorod and the size of silver nanoparticles were variables for discussion. Simulation results show that a large height of nanorod induces strong wavelength selectivity, which can be significantly enhanced by LSP. On condition that the height of nanorod is 400 nm, the diameter of silver nanoparticle is 100 nm, and the wavelength is 402.7 nm, the light-output efficiency for LSP assisted LED is enhanced by 190% or 541% as compared to the nanorod counterpart or the planar counterpart, respectively. The space distribution of Poynting vector was present to demonstrate the significant enhancement of light output at the resonant wavelength of LSP.

  4. Statistical studies on the light output and energy resolution of small LSO single crystals with different surface treatments combined with various reflector materials

    CERN Document Server

    Heinrichs, U; Bussmann, N; Engels, R; Kemmerling, G; Weber, S; Ziemons, K

    2002-01-01

    The optimization of light output and energy resolution of scintillators is of special interest for the development of high resolution and high sensitivity PET. The aim of this work is to obtain statistically reliable results concerning optimal surface treatment of scintillation crystals and the selection of reflector material. For this purpose, raw, mechanically polished and etched LSO crystals (size 2x2x10 mm sup 3) were combined with various reflector materials (Teflon tape, Teflon matrix, BaSO sub 4) and exposed to a sup 2 sup 2 Na source. In order to ensure the statistical reliability of the results, groups of 10 LSO crystals each were measured for all combinations of surface treatment and reflector material. Using no reflector material the light output increased up to 551+-35% by mechanical polishing the surface compared to 100+-5% for raw crystals. Etching the surface increased the light output to 441+-29%. The untreated crystals had an energy resolution of 24.6+-4.0%. By mechanical polishing the surfac...

  5. Safer Battery with Switchable Polymer Coating, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to utilize a switchable polymer (SWP) to prevent catastrophic failure due to internal shorting or overdischarge in lithium-ion...

  6. The opioid fentanyl affects light input, electrical activity and Per gene expression in the hamster suprachiasmatic nuclei.

    Science.gov (United States)

    Vansteensel, Mariska J; Magnone, Maria Chiara; van Oosterhout, Floor; Baeriswyl, Stéphanie; Albrecht, Urs; Albus, Henk; Dahan, Albert; Meijer, Johanna H

    2005-06-01

    The suprachiasmatic nuclei (SCN) contain a major circadian pacemaker, which is regulated by photic and nonphotic stimuli. Although enkephalins are present in the SCN, their role in phase regulation of the pacemaker is largely unknown. The opioid agonist fentanyl, a homologue of morphine, is an addictive drug that induces phase shifts of circadian rhythms in hamsters. We observed that these phase shifts are blocked by naloxone, which is a critical test for true opioid receptor involvement, and conclude that opioid receptors are the sole mediators of the actions of fentanyl on the circadian timing system. A strong interaction between opioids and light input was shown by the ability of fentanyl and light to completely block each other's phase shifts of behavioural activity rhythms. Neuronal ensemble recordings in vitro provide first evidence that SCN cells show direct responses to fentanyl and react with a suppression of firing rate. Moreover, we show that fentanyl induces a strong attenuation of light-induced Syrian hamster Period 1 (shPer1) gene expression during the night. During the subjective day, we found no evidence for a role of shPer1 in mediation of fentanyl-induced phase shifts. Based on the present results, however, we cannot exclude the involvement of shPer2. Our data indicate that opioids can strongly modify the photic responsiveness of the circadian pacemaker and may do so via direct effects on SCN electrical activity and regulation of Per genes. This suggests that the pathways regulating addictive behaviour and the circadian clock intersect.

  7. Switchable and Tunable Aerodynamic Drag on Cylinders

    Science.gov (United States)

    Guttag, Mark; Lopéz Jiménez, Francisco; Upadhyaya, Priyank; Kumar, Shanmugam; Reis, Pedro

    We report results on the performance of Smart Morphable Surfaces (Smporhs) that can be mounted onto cylindrical structures to actively reduce their aerodynamic drag. Our system comprises of an elastomeric thin shell with a series of carefully designed subsurface cavities that, once depressurized, lead to a dramatic deformation of the surface topography, on demand. Our design is inspired by the morphology of the giant cactus (Carnegiea gigantea) which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. We perform systematic wind tunnel tests on cylinders covered with our Smorphs and characterize their aerodynamic performance. The switchable and tunable nature of our system offers substantial advantages for aerodynamic performance when compared to static topographies, due to their operation over a wider range of flow conditions.

  8. Light output response of EJ-309 liquid organic scintillator to 2.86-3.95 MeV carbon recoil ions due to neutron elastic and inelastic scatter

    Science.gov (United States)

    Norsworthy, Mark A.; Ruch, Marc L.; Hamel, Michael C.; Clarke, Shaun D.; Hausladen, Paul A.; Pozzi, Sara A.

    2018-03-01

    We present the first measurements of energy-dependent light output from carbon recoils in the liquid organic scintillator EJ-309. For this measurement, neutrons were produced by an associated particle deuterium-tritium generator and scattered by a volume of EJ-309 scintillator into stop detectors positioned at four fixed angles. Carbon recoils in the scintillator were isolated using triple coincidence among the associated particle detector, scatter detector, and stop detectors. The kinematics of elastic and inelastic scatter allowed data collection at eight specific carbon recoil energies between 2.86 and 3.95 MeV. We found the light output caused by carbon recoils in this energy range to be approximately 1.14% of that caused by electrons of the same energy, which is comparable to the values reported for other liquid organic scintillators. A comparison of the number of scattered neutrons at each angle to a Monte Carlo N-Particle eXtended simulation indicates that the ENDF/B-VII.1 evaluation of differential cross sections for 14.1 MeV neutrons on carbon has discrepancies with the experiment as large as 55%, whereas those reported in the JENDL-4.0u evaluation agree with experiment.

  9. Further improvement in the light output power of InGaN-based light emitting diodes by reflective current blocking design

    International Nuclear Information System (INIS)

    Tsai, Chun-Fu; Su, Yan-Kuin; Lin, Chun-Liang

    2011-01-01

    In this study, the fabrication and characterization of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with further improvement by the design of a reflective current blocking layer (CBL) were described, and these are demonstrated to be an inexpensive and feasible way for improving the performance of LEDs. With the reflective CBL, not only was the injected current forced to spread outside instead of flowing directly downward under a p-pad, but the light generated from the active region could also be extracted outside of the LED by reflection under the p-pad. At 20 mA, as compared to the conventional LED, the light output power of the LEDs with the normal and reflective CBL can be increased by 15.7% and 25.8%, respectively. We found that the forward voltages of the LEDs with CBL structure were both about 3.7 V at 20 mA, which was slightly higher than that of the conventional LED (3.6 V). In our experiment, the further increase in the light output power of the reflective CBL LED could be attributed to more current injection into the light-emitting active region outside of the p-pad by the CBL and a reduction in optical absorption at the p-pad with more extraction by the reflective design

  10. Bridging “green gap” of LEDs: Giant light output enhancement and directional control of LEDs via embedded nano-void photonic crystals

    KAUST Repository

    Tsai, Yu-Lin

    2015-11-23

    Green LEDs do not show the same level of performance as their blue and red cousins, greatly hindering the solid-state lighting development, which is so-called “green gap”. In this work, nano-void photonic crystals (NVPCs) were fabricated to embed within the GaN/InGaN green LEDs by using epitaxial lateral overgrowth (ELO) and nano-sphere lithography techniques. The NVPCs act as an efficient scattering back-reflector to outcouple the guided and downward photons, which not only boosting light extraction efficiency of LEDs with an enhancement of 78% but also collimating the view angle of LEDs from 131.5゜to 114.0゜. This could be because the highly scattering nature of NVPCs which reduce the interference giving rise to Fabry-Perot resonance. Moreover, due to the threading dislocation suppression and strain relief by the NVPCs, the internal quantum efficiency was increased by 25% and droop behavior was reduced from 37.4% to 25.9%. The enhancement of light output power can be achieved as high as 151% at a driving current of 350 mA. Giant light output enhancement and directional control via NVPCs points the way towards a promising avenue of solid-state lighting.

  11. Photo-switchable microbial fuel-cells.

    Science.gov (United States)

    Schlesinger, Orr; Dandela, Rambabu; Bhagat, Ashok; Adepu, Raju; Meijler, Michael M; Xia, Lin; Alfonta, Lital

    2018-05-01

    Regulation of Bio-systems in a clean, simple, and efficient way is important for the design of smart bio-interfaces and bioelectronic devices. Light as a non-invasive mean to control the activity of a protein enables spatial and temporal control far superior to other chemical and physical methods. The ability to regulate the activity of a catalytic enzyme in a biofuel-cell reduces the waste of resources and energy and turns the fuel-cell into a smart and more efficient device for power generation. Here we present a microbial-fuel-cell based on a surface displayed, photo-switchable alcohol dehydrogenase. The enzyme was modified near the active site using non-canonical amino acids and a small photo-reactive molecule, which enables reversible control of enzymatic activity. Depending on the modification site, the enzyme exhibits reversible behavior upon irradiation with UV and visible light, in both biochemical, and electrochemical assays. The change observed in power output of a microbial fuel cell utilizing the modified enzyme was almost five-fold, between inactive and active states. © 2018 Wiley Periodicals, Inc.

  12. Ferroelectric based catalysis: Switchable surface chemistry

    Science.gov (United States)

    Kakekhani, Arvin; Ismail-Beigi, Sohrab

    2015-03-01

    We describe a new class of catalysts that uses an epitaxial monolayer of a transition metal oxide on a ferroelectric substrate. The ferroelectric polarization switches the surface chemistry between strongly adsorptive and strongly desorptive regimes, circumventing difficulties encountered on non-switchable catalytic surfaces where the Sabatier principle dictates a moderate surface-molecule interaction strength. This method is general and can, in principle, be applied to many reactions, and for each case the choice of the transition oxide monolayer can be optimized. Here, as a specific example, we show how simultaneous NOx direct decomposition (into N2 and O2) and CO oxidation can be achieved efficiently on CrO2 terminated PbTiO3, while circumventing oxygen (and sulfur) poisoning issues. One should note that NOx direct decomposition has been an open challenge in automotive emission control industry. Our method can expand the range of catalytically active elements to those which are not conventionally considered for catalysis and which are more economical, e.g., Cr (for NOx direct decomposition and CO oxidation) instead of canonical precious metal catalysts. Primary support from Toyota Motor Engineering and Manufacturing, North America, Inc.

  13. Effective lipid extraction from algae cultures using switchable solvents

    NARCIS (Netherlands)

    Samori, Chiara; Lopez Barreiro, D.; Vet, Robin; Pezzolesi, Laura; Brilman, Derk Willem Frederik; Galletti, Paola; Tagliavini, Emilio

    2013-01-01

    A new procedure based on switchable polarity solvents (SPS) was proposed for lipid extraction of wet algal samples or cultures, thereby circumventing the need for an energy intensive drying step and facilitating easy recovery of the lipids from the extraction liquid. Lipids were extracted by using

  14. Switchable capacitor and method of making the same

    NARCIS (Netherlands)

    Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, Hendrikus; De Raedt, Walter

    2006-01-01

    A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom electrode, a dielectric layer deposited on at least part of said bottom electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to

  15. Switchable capacitor and method of making the same

    NARCIS (Netherlands)

    Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, Hendrikus; De Raedt, Walter

    2003-01-01

    A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom electrode, a dielectric layer deposited on at least part of said bottom electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to

  16. Improved light output power in GaN-based vertical light-emitting diodes with p-AlInGaN/GaN superlattices

    International Nuclear Information System (INIS)

    Kim, Su Jin; Son, Sung Hun; Kim, Tae Geun

    2012-01-01

    In this paper, we report the effect of p-type AlGaInN/GaN superlattices (SLs) as electron blocking layers (EBLs) on the optical properties of vertical light-emitting diodes (VLEDs). Using p-AlGaInN/GaN SLs in VLEDs, we have achieved significant improvements in the output power and the external quantum efficiency (EQE) as compared to VLEDs using p-AlGaInN EBL and p-AlGaN EBL. The forward voltages at 350 mA were calculated to be 4.1, 4.3, and 4.4 V for VLEDs with p-AlInGaN/GaN SLs, p-AlInGaN, and p-AlGaN EBLs, respectively. When p-AlInGaN/GaN SLs were inserted as the EBLs, the light-output power and the EQE were also improved by 16.8% and 17.3% at 350 mA, respectively, as compared to those with p-AlGaN EBLs.

  17. Switchable and responsive surfaces and materials for biomedical applications

    CERN Document Server

    Zhang, Johnathan

    2015-01-01

    Surface modification of biomaterials can ultimately determine whether a material is accepted or rejected from the human body, and a responsive surface can further make the material ""smart"" and ""intelligent"". Switchable and Responsive Surfaces and Materials for Biomedical Applications outlines synthetic and biological materials that are responsive under different stimuli, their surface design and modification techniques, and applicability in regenerative medicine/tissue engineering,  drug delivery, medical devices, and biomedical diagnostics. Part one provides a detailed overview of swit

  18. Plasma-based localized defect for switchable coupling applications

    International Nuclear Information System (INIS)

    Varault, Stefan; Gabard, Benjamin; Sokoloff, Jerome; Bolioli, Sylvain

    2011-01-01

    We report in this paper experimental measurements in order to validate the concept of switchable electromagnetic band gap filters based on plasma capillaries in the microwave regime. The plasma tube is embedded inside the structure to create a bistable (plasma on or off) punctual defect. We first investigate two kinds of discharge tubes: Ar-Hg and pure Ne, which we then use to experimentally achieve plasma-based reconfigurable applications, namely, a two-port coupler and a two-port demultiplexer.

  19. Phase Change of Gallium Enables Highly Reversible and Switchable Adhesion.

    Science.gov (United States)

    Ye, Zhou; Lum, Guo Zhan; Song, Sukho; Rich, Steven; Sitti, Metin

    2016-07-01

    Gallium exhibits highly reversible and switchable adhesion when it undergoes a solid-liquid phase transition. The robustness of gallium is notable as it exhibits strong performance on a wide range of smooth and rough surfaces, under both dry and wet conditions. Gallium may therefore find numerous applications in transfer printing, robotics, electronic packaging, and biomedicine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. High-brightness switchable multiwavelength remote laser in air

    Energy Technology Data Exchange (ETDEWEB)

    Yao Jinping; Cheng Ya; Xu Zhizhan [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Zeng Bin; Li Guihua; Chu Wei; Ni Jielei; Zhang Haisu [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School of Chinese Academy of Sciences, Beijing 100080 (China); Xu Huailiang [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Chin, See Leang [Center for Optics, Universite Laval, Quebec City, Quebec G1V 0A6 (Canada)

    2011-11-15

    We demonstrate a harmonic-seeded switchable multiwavelength laser in air driven by intense midinfrared femtosecond laser pulses, in which population inversion occurs at an ultrafast time scale (i.e., less than {approx}200 fs) owing to direct formation of excited molecular nitrogen ions by strong-field ionization of inner-valence electrons. The bright multiwavelength laser in air opens the perspective for remote detection of multiple pollutants based on nonlinear optical spectroscopy.

  1. Mechanics of responsive polymers via conformationally switchable molecules

    Science.gov (United States)

    Brighenti, Roberto; Artoni, Federico; Vernerey, Franck; Torelli, Martina; Pedrini, Alessandro; Domenichelli, Ilaria; Dalcanale, Enrico

    2018-04-01

    Active materials are those capable of giving some physical reaction under external stimuli coming from the environment such as temperature, pH, light, mechanical stress, etc. Reactive polymeric materials can be obtained through the introduction of switchable molecules in their network, i.e. molecules having two distinct stable conformations: if properly linked to the hosting polymer chains, the switching from one state to the other can promote a mechanical reaction of the material, detectable at the macroscale, and thus enables us to tune the response according to a desired functionality. In the present paper, the main aspects of the mechanical behavior of polymeric materials with embedded switchable molecules-properly linked to the polymer's chains-are presented and discussed. Starting from the micro mechanisms occurring in such active material, a continuum model is developed, providing a straightforward implementation in computational approaches. Finally, some experimental outcomes related to a switchable molecules (known as quinoxaline cavitands) added to an elastomeric PDMS under chemical stimuli, are presented and quantitatively discussed through the use of the developed mechanical framework.

  2. Light output improvement of GaN-based light-emitting diodes grown on Si (111) by a via-thin-film structure

    Science.gov (United States)

    Li, Zengcheng; Feng, Bo; Deng, Biao; Liu, Legong; Huang, Yingnan; Feng, Meixin; Zhou, Yu; Zhao, Hanmin; Sun, Qian; Wang, Huaibing; Yang, Xiaoli; Yang, Hui

    2018-04-01

    This work reports the fabrication of via-thin-film light-emitting diode (via-TF-LED) to improve the light output power (LOP) of blue/white GaN-based LEDs grown on Si (111) substrates. The as-fabricated via-TF-LEDs were featured with a roughened n-GaN surface and the p-GaN surface bonded to a wafer carrier with a silver-based reflective electrode, together with an array of embedded n-type via pillar metal contact from the p-GaN surface etched through the multiple-quantum-wells (MQWs) into the n-GaN layer. When operated at 350 mA, the via-TF-LED gave an enhanced blue LOP by 7.8% and over 3.5 times as compared to the vertical thin-film LED (TF-LED) and the conventional lateral structure LED (LS-LED). After covering with yellow phosphor that converts some blue photons into yellow light, the via-TF-LED emitted an enhanced white luminous flux by 13.5% and over 5 times, as compared with the white TF-LED and the white LS-LED, respectively. The significant LOP improvement of the via-TF-LED was attributed to the elimination of light absorption by the Si (111) epitaxial substrate and the finger-like n-electrodes on the roughened emitting surface. Project supported by the National Key R&D Program (Nos. 2016YFB0400100, 2016YFB0400104), the National Natural Science Foundation of China (Nos. 61534007, 61404156, 61522407, 61604168, 61775230), the Key Frontier Scientific Research Program of the Chinese Academy of Sciences (No. QYZDB-SSW-JSC014), the Science and Technology Service Network Initiative of the Chinese Academy of Sciences, the Key R&D Program of Jiangsu Province (No. BE2017079), the Natural Science Foundation of Jiangsu Province (No. BK20160401), and the China Postdoctoral Science Foundation (No. 2016M591944). This work was also supported by the Open Fund of the State Key Laboratory of Luminescence and Applications (No. SKLA-2016-01), the Open Fund of the State Key Laboratory on Integrated Optoelectronics (Nos. IOSKL2016KF04, IOSKL2016KF07), and the Seed Fund from SINANO

  3. Ferroelectric nanostructure having switchable multi-stable vortex states

    Science.gov (United States)

    Naumov, Ivan I [Fayetteville, AR; Bellaiche, Laurent M [Fayetteville, AR; Prosandeev, Sergey A [Fayetteville, AR; Ponomareva, Inna V [Fayetteville, AR; Kornev, Igor A [Fayetteville, AR

    2009-09-22

    A ferroelectric nanostructure formed as a low dimensional nano-scale ferroelectric material having at least one vortex ring of polarization generating an ordered toroid moment switchable between multi-stable states. A stress-free ferroelectric nanodot under open-circuit-like electrical boundary conditions maintains such a vortex structure for their local dipoles when subject to a transverse inhomogeneous static electric field controlling the direction of the macroscopic toroidal moment. Stress is also capable of controlling the vortex's chirality, because of the electromechanical coupling that exists in ferroelectric nanodots.

  4. On/off-switchable anti-neoplastic nanoarchitecture

    Science.gov (United States)

    Patra, Hirak K.; Imani, Roghayeh; Jangamreddy, Jaganmohan R.; Pazoki, Meysam; Iglič, Aleš; Turner, Anthony P. F.; Tiwari, Ashutosh

    2015-09-01

    Throughout the world, there are increasing demands for alternate approaches to advanced cancer therapeutics. Numerous potentially chemotherapeutic compounds are developed every year for clinical trial and some of them are considered as potential drug candidates. Nanotechnology-based approaches have accelerated the discovery process, but the key challenge still remains to develop therapeutically viable and physiologically safe materials suitable for cancer therapy. Here, we report a high turnover, on/off-switchable functionally popping reactive oxygen species (ROS) generator using a smart mesoporous titanium dioxide popcorn (TiO2 Pops) nanoarchitecture. The resulting TiO2 Pops, unlike TiO2 nanoparticles (TiO2 NPs), are exceptionally biocompatible with normal cells. Under identical conditions, TiO2 Pops show very high photocatalytic activity compared to TiO2 NPs. Upon on/off-switchable photo activation, the TiO2 Pops can trigger the generation of high-turnover flash ROS and can deliver their potential anticancer effect by enhancing the intracellular ROS level until it crosses the threshold to open the ‘death gate’, thus reducing the survival of cancer cells by at least six times in comparison with TiO2 NPs without affecting the normal cells.

  5. Adhesion of Chlamydomonas microalgae to surfaces is switchable by light

    Science.gov (United States)

    Kreis, Christian Titus; Le Blay, Marine; Linne, Christine; Makowski, Marcin Michal; Bäumchen, Oliver

    2018-01-01

    Microalgae are photoactive microbes that live in liquid-infused environments, such as soil, temporary pools and rocks, where they encounter and colonize a plethora of surfaces. Their photoactivity manifests itself in a variety of processes, including light-directed motility (phototaxis), the growth of microalgal populations, and their photosynthetic machinery. Although microbial responses to light have been widely recognized, any influence of light on cell-surface interactions remains elusive. Here, we reveal that the unspecific adhesion of microalgae to surfaces can be reversibly switched on and off by light. Using a micropipette force spectroscopy technique, we measured in vivo single-cell adhesion forces and show that the microalga's flagella provide light-switchable adhesive contacts with the surface. This light-induced adhesion to surfaces is an active and completely reversible process that occurs on a timescale of seconds. Our results suggest that light-switchable adhesiveness is a natural functionality of microalgae to regulate the transition between the planktonic and the surface-associated state, which yields an adhesive adaptation to optimize the photosynthetic efficiency in conjunction with phototaxis.

  6. Adhesion of Photoactive Microalgae to Surfaces is Switchable by Light

    Science.gov (United States)

    Bäumchen, Oliver; Kreis, Christian; Le Blay, Marine; Linne, Christine; Makowski, Marcin

    The natural habitats of many microorganisms are confined geometries, such as the interstitial space of rocks and soil, where interactions with interfaces and surfaces are of paramount importance. We performed in vivo force spectroscopy experiments on the unicellular biflagellated microalga Chlamydomonas, a prime model organism in cell- and microbiology, and discovered that the flagella-mediated adhesion to surfaces can be switched on and off by light. Time-resolved micropipette experiments show that the light-switchable adhesiveness of the flagella is a completely reversible process that is based on a redistribution of adhesion-promoting flagella-membrane proteins within seconds. Light-switchable adhesion enables the cell to regulate the transition between planktonic and surface-associated state, which possibly represents a significant biological advantage for photoactive microorganisms. In terms of the colonization of surfaces and the formation of biofilms, the findings might have immediate economic and environmental relevance in biotechnological settings, such as photo-bioreactors for the sustainable production of biofuels.

  7. Switchable photosystem-II designer algae for photobiological hydrogen production

    Science.gov (United States)

    Lee, James Weifu

    2010-01-05

    A switchable photosystem-II designer algae for photobiological hydrogen production. The designer transgenic algae includes at least two transgenes for enhanced photobiological H.sub.2 production wherein a first transgene serves as a genetic switch that can controls photosystem II (PSII) oxygen evolution and a second transgene encodes for creation of free proton channels in the algal photosynthetic membrane. In one embodiment, the algae includes a DNA construct having polymerase chain reaction forward primer (302), a inducible promoter (304), a PSII-iRNA sequence (306), a terminator (308), and a PCR reverse primer (310). In other embodiments, the PSII-iRNA sequence (306) is replaced with a CF.sub.1-iRNA sequence (312), a streptomycin-production gene (314), a targeting sequence (316) followed by a proton-channel producing gene (318), or a PSII-producing gene (320). In one embodiment, a photo-bioreactor and gas-product separation and utilization system produce photobiological H.sub.2 from the switchable PSII designer alga.

  8. A Self-Switchable Polymer Reactor for Controlled Catalytic Chemistry Processes with a Hyperbranched Structure

    Directory of Open Access Journals (Sweden)

    Rong Luo

    2018-02-01

    Full Text Available A self-switchable polymer reactor with a hyperbranched structure for controlled catalytic chemistry processes is reported. This polymer reactor was made of silver nanoparticles and a polymer carrier consisting of hyperbranched polyethylenimine and hydroxyethyl acrylate that behaved as thermally switchable domains. Below the transfer temperature, relatively strong catalytic reactivity was demonstrated due to the leading role of hydrophilic groups in the switchable domains, which opened access to the substrate for the packaged silver nanoparticles. In contrast, it showed weak catalysis at relatively high temperatures, reducing from the significantly increased hydrophobicity in the switchable domains. In this way, the polymer reactor displays controllable, tunable, catalytic activity based on this approach. This novel design opens up the opportunity to develop intelligent polymer reactors for controlled catalytic processes.

  9. Self-organization of anisotropic and binary colloids in thermo-switchable 1D microconfinement

    NARCIS (Netherlands)

    De Folter, Julius W J; Liu, Ping; Jiang, Lingxiang; Kuijk, Anke; Bakker, Henriëtte E.; Imhof, Arnout; Van Blaaderen, Alfons; Huang, Jianbin; Kegel, Willem K.; Philipse, Albert P.; Petukhov, Andrei V.

    2015-01-01

    Anisotropic and binary colloids self-assemble into a variety of novel supracolloidal structures within the thermo-switchable confinement of molecular microtubes, achieving structuring at multiple length scales and dimensionalities. The multistage self-assembly strategy involving hard colloidal

  10. Nanoporous membranes with electrochemically switchable, chemically stabilized ionic selectivity

    Science.gov (United States)

    Small, Leo J.; Wheeler, David R.; Spoerke, Erik D.

    2015-10-01

    Nanopore size, shape, and surface charge all play important roles in regulating ionic transport through nanoporous membranes. The ability to control these parameters in situ provides a means to create ion transport systems tunable in real time. Here, we present a new strategy to address this challenge, utilizing three unique electrochemically switchable chemistries to manipulate the terminal functional group and control the resulting surface charge throughout ensembles of gold plated nanopores in ion-tracked polycarbonate membranes 3 cm2 in area. We demonstrate the diazonium mediated surface functionalization with (1) nitrophenyl chemistry, (2) quinone chemistry, and (3) previously unreported trimethyl lock chemistry. Unlike other works, these chemistries are chemically stabilized, eliminating the need for a continuously applied gate voltage to maintain a given state and retain ionic selectivity. The effect of surface functionalization and nanopore geometry on selective ion transport through these functionalized membranes is characterized in aqueous solutions of sodium chloride at pH = 5.7. The nitrophenyl surface allows for ionic selectivity to be irreversibly switched in situ from cation-selective to anion-selective upon reduction to an aminophenyl surface. The quinone-terminated surface enables reversible changes between no ionic selectivity and a slight cationic selectivity. Alternatively, the trimethyl lock allows ionic selectivity to be reversibly switched by up to a factor of 8, approaching ideal selectivity, as a carboxylic acid group is electrochemically revealed or hidden. By varying the pore shape from cylindrical to conical, it is demonstrated that a controllable directionality can be imparted to the ionic selectivity. Combining control of nanopore geometry with stable, switchable chemistries facilitates superior control of molecular transport across the membrane, enabling tunable ion transport systems.Nanopore size, shape, and surface charge all play

  11. Band-Notched UWB Antenna with Switchable and Tunable Performance

    Directory of Open Access Journals (Sweden)

    Wei Wu

    2016-01-01

    Full Text Available A band-notched UWB antenna is presented, which can switch between two notch bands and tune the central frequency simultaneously. It is the first time that the switchable and tunable behaviours are combined together in band-notched UWB antennas. In the band-notched structure, PIN diodes are used to switch the lower and upper frequency bands, while varactors could vary the central frequency of each notch band continuously. Measurement results show that the notch bands could switch between 4.2 GHz and 5.8 GHz when the state of varactors is fixed, and the ranges of tuning are 4.2–4.8 GHz and 5.8–6.5 GHz when the state of PIN diodes is ON and OFF, respectively.

  12. Chromogenic switchable glazing: Towards the development of the smart window

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, C.M.

    1995-06-01

    The science and technology of chromogenic materials for switchable glazings in building applications is discussed. These glazings can be used for dynamic control of solar and visible energy. Currently many researchers and engineers are involved with the development of products in this field. A summary of activities in Japan, Europe, Australia, USA and Canada is made. The activities of the International Energy Agency are included. Both non-electrically activated and electrically activated glazings are discussed. Technologies covered in the first category are photochromics, and thermochromics and thermotropics. A discussion of electrically activated chromogenic glazings includes dispersed liquid crystals, dispersed particles and electrochromics. A selection of device structures and performance characteristics are compared. A discussion of transparent conductors is presented. Technical issues concerning large-area development of smart windows are discussed.

  13. Electrical Switchability and Dry-Wash Durability of Conductive Textiles.

    Science.gov (United States)

    Wu, Bangting; Zhang, Bowu; Wu, Jingxia; Wang, Ziqiang; Ma, Hongjuan; Yu, Ming; Li, Linfan; Li, Jingye

    2015-06-12

    There is growing interest in the area of conductive textiles in the scientific and industrial community. Herein, we successfully prepared a conductive textile via covalently grafting polyaniline (PANI) onto cotton by a multi-step treatment process. The conductivity of the resultant fabric could be tuned by immersing in water having different pH values. The conductive and insulating properties of the textile could be conveniently switched by alternately immersing in acidic and alkaline bath solutions. Most importantly, the resultant conductive fabrics were able to withstand 40 simulated dry-wash cycles, with almost no decay in the electrical conductivity, indicating their excellent dry-wash durability. The present strategy for fabricating conductive fabrics with excellent switchability of electrical properties and dry-wash durability is expected to provide inspiration for the production of multifunctional conductive textiles for use in hash or sensitive conditions.

  14. High quality factor, fully switchable terahertz superconducting metasurface

    Energy Technology Data Exchange (ETDEWEB)

    Scalari, G., E-mail: scalari@phys.ethz.ch; Maissen, C.; Faist, J. [Institute of Quantum Electronics, Eidgenössische Technische Hochschule Zürich (Switzerland); Cibella, S.; Leoni, R. [Istituto di Fotonica e Nanotecnologie (IFN), CNR, via Cineto Romano 42, 00156 Rome (Italy)

    2014-12-29

    We present a complementary THz metasurface realised with Niobium thin film which displays a quality factor Q = 54 and a fully switchable behaviour as a function of the temperature. The switching behaviour and the high quality factor are due to a careful design of the metasurface aimed at maximising the ohmic losses when the Nb is above the critical temperature and minimising the radiative coupling. The superconductor allows the operation of the cavity with high Q and the use of inductive elements with a high aspect ratio. Comparison with three dimensional finite element simulations highlights the crucial role of the inductive elements and of the kinetic inductance of the Cooper pairs in achieving the high quality factor and the high field enhancement.

  15. Electrical Switchability and Dry-Wash Durability of Conductive Textiles

    Science.gov (United States)

    Wu, Bangting; Zhang, Bowu; Wu, Jingxia; Wang, Ziqiang; Ma, Hongjuan; Yu, Ming; Li, Linfan; Li, Jingye

    2015-06-01

    There is growing interest in the area of conductive textiles in the scientific and industrial community. Herein, we successfully prepared a conductive textile via covalently grafting polyaniline (PANI) onto cotton by a multi-step treatment process. The conductivity of the resultant fabric could be tuned by immersing in water having different pH values. The conductive and insulating properties of the textile could be conveniently switched by alternately immersing in acidic and alkaline bath solutions. Most importantly, the resultant conductive fabrics were able to withstand 40 simulated dry-wash cycles, with almost no decay in the electrical conductivity, indicating their excellent dry-wash durability. The present strategy for fabricating conductive fabrics with excellent switchability of electrical properties and dry-wash durability is expected to provide inspiration for the production of multifunctional conductive textiles for use in hash or sensitive conditions.

  16. Enhancement of light output power of GaN-based light-emitting diodes with photonic quasi-crystal patterned on p-GaN surface and n-side sidewall roughing

    Science.gov (United States)

    2013-01-01

    In this paper, GaN-based light-emitting diodes (LEDs) with photonic quasi-crystal (PQC) structure on p-GaN surface and n-side roughing by nano-imprint lithography are fabricated and investigated. At an injection current of 20 mA, the LED with PQC structure on p-GaN surface and n-side roughing increased the light output power of the InGaN/GaN multiple quantum well LEDs by a factor of 1.42, and the wall-plug efficiency is 26% higher than the conventional GaN-based LED type. After 500-h life test (55°C/50 mA), it was found that the normalized output power of GaN-based LED with PQC structure on p-GaN surface and n-side roughing only decreased by 6%. These results offer promising potential to enhance the light output powers of commercial light-emitting devices using the technique of nano-imprint lithography. PMID:23683526

  17. Switchable regioselectivity in amine-catalysed asymmetric cycloadditions

    Science.gov (United States)

    Zhou, Zhi; Wang, Zhou-Xiang; Zhou, Yuan-Chun; Xiao, Wei; Ouyang, Qin; Du, Wei; Chen, Ying-Chun

    2017-06-01

    Building small-molecule libraries with structural and stereogenic diversity plays an important role in drug discovery. The development of switchable intermolecular cycloaddition reactions from identical substrates in different regioselective fashions would provide an attractive protocol. However, this also represents a challenge in organic chemistry, because it is difficult to control regioselectivity to afford the products exclusively and at the same time achieve high levels of stereoselectivity. Here, we report the diversified cycloadditions of α‧-alkylidene-2-cyclopentenones catalysed by cinchona-derived primary amines. An asymmetric γ,β‧-regioselective intermolecular [6+2] cycloaddition reaction with 3-olefinic (7-aza)oxindoles is realized through the in situ generation of formal 4-aminofulvenes, while a different β,γ-regioselective [2+2] cycloaddition reaction with maleimides to access fused cyclobutanes is disclosed. In contrast, an intriguing α,γ-regioselective [4+2] cycloaddition reaction is uncovered with the same set of substrates, by employing an unprecedented dual small-molecule catalysis of amines and thiols. All of the cycloaddition reactions exhibit excellent regio- and stereoselectivity, producing a broad spectrum of chiral architectures with high structural diversity and molecular complexity.

  18. Switchable ionic liquids as delignification solvents for lignocellulosic materials.

    Science.gov (United States)

    Anugwom, Ikenna; Eta, Valerie; Virtanen, Pasi; Mäki-Arvela, Päivi; Hedenström, Mattias; Hummel, Michael; Sixta, Herbert; Mikkola, Jyri-Pekka

    2014-04-01

    The transformation of lignocellulosic materials into potentially valuable resources is compromised by their complicated structure. Consequently, new economical and feasible conversion/fractionation techniques that render value-added products are intensely investigated. Herein an unorthodox and feasible fractionation method of birch chips (B. pendula) using a switchable ionic liquid (SIL) derived from an alkanol amine (monoethanol amine, MEA) and an organic super base (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) with two different trigger acid gases (CO2 and SO2 ) is studied. After SIL treatment, the dissolved fractions were selectively separated by a step-wise method using an antisolvent to induce precipitation. The SIL was recycled after concentration and evaporation of anti-solvent. The composition of undissolved wood after MEA-SO2 -SIL treatment resulted in 80 wt % cellulose, 10 wt % hemicelluloses, and 3 wt % lignin, whereas MEA-CO2 -SIL treatment resulted in 66 wt % cellulose, 12 wt % hemicelluloses and 11 wt % lignin. Thus, the MEA-SO2 -SIL proved more efficient than the MEA-CO2 -SIL, and a better solvent for lignin removal. All fractions were analyzed by gas chromatography (GC), Fourier transform infrared spectroscopy (FT-IR), (13) C nuclear magnetic resonance spectroscopy (NMR) and Gel permeation chromatography (GPC). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives.

    Science.gov (United States)

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-11-04

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structures. In this study, we demonstrate that these adhesives are capable of switching adhesion not only in ambient air conditions but also in vacuum. Our bioinspired patterned adhesive with an area of 1 cm(2) provided an adhesion force of 2.6 N ± 0.2 N in air, which was reduced to 1.9 N ± 0.2 N if measured in vacuum. Detachment was induced by buckling of the structures due to a high compressive preload and occurred, independent of air pressure, at approximately 0.9 N ± 0.1 N. The switch in adhesion was observed at a compressive preload between 5.6 and 6.0 N and was independent of air pressure. The difference between maximum adhesion force and adhesion force after buckling gives a reasonable window of operation for pick and place processes. High reversibility of the switching behavior is shown over 50 cycles in air and in vacuum, making the bioinspired switchable adhesive applicable for handling operations of fragile objects.

  20. Switchable multiwavelength fiber laser using erbium-doped twin-core fiber and nonlinear polarization rotation

    Science.gov (United States)

    Lian, Yudong; Ren, Guobin; Zhu, Bofeng; Gao, Yixiao; Jian, Wei; Ren, Wenhua; Jian, Shuisheng

    2017-05-01

    We propose and demonstrate a switchable multiwavelength fiber laser using erbium-doped twin-core fiber (ED-TCF) and nonlinear polarization rotation (NPR). The number switchability of lasing wavelengths being switched from 1 to 4 and wavelength location switchability could be achieved simultaneously in the proposed configuration with a wavelength spacing of 1.1 nm and an optical signal to noise ratio (OSNR) larger than 43 dB. The output laser powers at different wavelengths are nearly the same with a fluctuation less than 2 dB. The proposed fiber laser shows good stability with wavelength shift within 0.01 nm and peak power fluctuation less than 5 dB. The proposed fiber laser has the advantages of simple structure and stable operation.

  1. Enhanced and switchable spin Hall effect of light near the Brewster angle on reflection

    International Nuclear Information System (INIS)

    Luo Hailu; Zhou Xinxing; Shu Weixing; Wen Shuangchun; Fan Dianyuan

    2011-01-01

    We theorize an enhanced and switchable spin Hall effect (SHE) of light near the Brewster angle on reflection and demonstrate it experimentally. The obtained spin-dependent splitting reaches 3200 nm near the Brewster angle, which is 50 times larger than the previously reported values in refraction. We find that the amplifying factor in weak measurement is not a constant, which is significantly different from that in refraction. As an analogy of SHE in an electronic system, a switchable spin accumulation in SHE of light is detected. We were able to switch the direction of the spin accumulations by slightly adjusting the incident angle.

  2. Optimal control and performance of photovoltachromic switchable glazing for building integration in temperate climates

    International Nuclear Information System (INIS)

    Favoino, Fabio; Fiorito, Francesco; Cannavale, Alessandro; Ranzi, Gianluca; Overend, Mauro

    2016-01-01

    Highlights: • The features and properties of photovoltachromic switchable glazing are presented. • The different possible control strategies for the switchable glazing are presented. • Thermal and daylight performance are co-simulated for rule-based and optimal control. • A novel building performance simulation framework is developed for this aim. • Switchable glazing performance is compared for different controls and climates. - Abstract: The development of adaptive building envelope technologies, and particularly of switchable glazing, can make significant contributions to decarbonisation targets. It is therefore essential to quantify their effect on building energy use and indoor environmental quality when integrated into buildings. The evaluation of their performance presents new challenges when compared to conventional “static” building envelope systems, as they require design and control aspects to be evaluated together, which are also mutually interrelated across thermal and visual physical domains. This paper addresses these challenges by presenting a novel simulation framework for the performance evaluation of responsive building envelope technologies and, particularly, of switchable glazing. This is achieved by integrating a building energy simulation tool and a lighting simulation one, in a control optimisation framework to simulate advanced control of adaptive building envelopes. The performance of a photovoltachromic glazing is evaluated according to building energy use, Useful Daylight Illuminance, glare risk and load profile matching indicators for a sun oriented office building in different temperate climates. The original architecture of photovoltachromic cell provides an automatic control of its transparency as a function of incoming solar irradiance. However, to fully explore the building integration potential of photovoltachromic technology, different control strategies are evaluated, from passive and simple rule based controls, to

  3. Enhanced light output power of GaN-based vertical-injection light-emitting diodes with a 12-fold photonic quasi-crystal by nano-imprint lithography

    International Nuclear Information System (INIS)

    Huang, H W; Huang, J K; Kuo, H C; Wang, S C; Lin, C H; Lee, K Y; Yu, C C; Lee, B D; Leung, K M

    2009-01-01

    GaN-based thin-film vertical-injection light-emitting diodes (VLEDs) with a 12-fold photonic quasi-crystal (PQC) by nano-imprint lithography (NIL) are fabricated and presented. At a driving current of 20 mA and with a chip size of 350 µm × 350 µm, the light output power of our thin-film LED with a 12-fold PQC structure reaches 41 mW. This result is an enhancement of 78% when compared with the output power of a VLED without a PQC structure. In addition, the corresponding light radiation pattern shows a narrower beam shape due to the strong guided light extraction effect by the formed PQC structure in the vertical direction

  4. A redox-switchable Au8-cluster sensor.

    Science.gov (United States)

    Wu, Te-Haw; Hsu, Yu-Yen; Lin, Shu-Yi

    2012-07-09

    The proof of concept of a simple sensing platform based on the fluorescence of a gold cluster consisting of eight atoms, which is easily manipulated by reduction and oxidation of a specific molecule in the absence of chemical linkers, is demonstrated. Without using any coupling reagents to arrange the distance of the donor-acceptor pair, the fluorescence of the Au(8) -cluster is immediately switched off in the presence of 2-pyridinethiol (2-PyT) quencher. Through an upward-curving Stern-Volmer plot, the system shows complex fluorescence quenching with a combination of static and dynamic quenching processes. To analyze the static quenching constant (V) by a "sphere of action" model, the collisional encounter between the Au(8) -cluster and 2-PyT presents a quenching radius (r) ≈5.8 nm, which is larger than the sum of the radii of the Au(8) -cluster and 2-PyT. This implies that fluorescence quenching can occur even though the Au(8) -cluster and 2-PyT are not very close to each other. The quenching pathway may be derived from a photoinduced electron-transfer process of the encounter pair between the Au(8) -cluster (as an electron donor) and 2-PyT (as an electron acceptor) to allow efficient fluorescence quenching in the absence of coupling reagents. Interestingly, the fluorescence is restored by oxidation of 2-PyT to form the corresponding disulfide compound and then quenched again after the reduction of the disulfide. This redox-switchable fluorescent Au(8) -cluster platform is a novel discovery, and its utility as a promising sensor for detecting H(2) O(2) -generating enzymatic transformations is demonstrated. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Techniques to Improve Ultrasound-Switchable Fluorescence Imaging

    Science.gov (United States)

    Kandukuri, Jayanth

    Novel approaches to the improvement of ultrasound-switchable fluorescence (USF) imaging--a relatively new imaging modality that combines ultrasound and optical imaging techniques--have been proposed for early cancer detection. In USF, a high-intensity focused ultrasound (HIFU) beam is used to induce temperature rise within its acoustic focal region due to which a thermo-sensitive USF contrast agent undergoes a switch in its state by increasing the output of fluorescence photons. By using an increase in fluorescence, one can isolate and quantify the fluorescence properties within the ultrasonic focal area. Therefore, USF is able to provide fluorescence contrast while maintaining ultrasound resolution in tissue. The major challenge of the conventional USF technique is its low axial resolution and its sensitivity (i.e. its signal-to-noise ratio (SNR)). This work focuses on investigating and developing a novel USF system design that can improve the resolution and SNR of USF imaging for biological applications. This work can be divided into two major parts: characterizing the performance of a high-intensity focused ultrasound transducer; and improving the axial resolution and sensitivity of the USF technique. Preliminary investigation was conducted by using an IR camera setup to detect temperature variation and thereby study the performance of the high-intensity focused ultrasound transducer to quantify different parameters of ultrasound-induced temperature focal size (UTFS). Investigations are conducted for the purpose of high-resolution imaging with an emphasis on HIFU-induced thermal focus size, short duration of HIFU-induced temperature increase (to avoid thermal diffusion or conduction), and control of HIFU-induced temperature increase within a few degrees Celsius. Next, the focus was shifted to improving the sensitivity of the ultrasound-switchable fluorescence-imaging technique. In this study, the USF signal is encoded with the modulation frequency of the

  6. Secondary amines as switchable solvents for lipid extraction from non-broken microalgae

    NARCIS (Netherlands)

    Du, Ying; Schuur, Boelo; Samori, C.; Tagliavini, E.; Brilman, Derk Willem Frederik

    2013-01-01

    Lipids from algal biomass may provide renewable fuel and chemical feedstock in large quantities. The energy intensity of drying and milling of algae prior to extraction and of solvent recovery afterwards is a major obstacle. The objective is to use switchable solvents to extract oil directly from

  7. Temperature-Induced Switchable Adhesion using Nickel-Titanium-Polydimethylsiloxane Hybrid Surfaces.

    Science.gov (United States)

    Frensemeier, Mareike; Kaiser, Jessica S; Frick, Carl P; Schneider, Andreas S; Arzt, Eduard; Fertig, Ray S; Kroner, Elmar

    2015-05-01

    A switchable dry adhesive based on a nickel-titanium (NiTi) shape-memory alloy with an adhesive silicone rubber surface has been developed. Although several studies investigate micropatterned, bioinspired adhesive surfaces, very few focus on reversible adhesion. The system here is based on the indentation-induced two-way shape-memory effect in NiTi alloys. NiTi is trained by mechanical deformation through indentation and grinding to elicit a temperature-induced switchable topography with protrusions at high temperature and a flat surface at low temperature. The trained surfaces are coated with either a smooth or a patterned adhesive polydimethylsiloxane (PDMS) layer, resulting in a temperature-induced switchable surface, used for dry adhesion. Adhesion tests show that the temperature-induced topographical change of the NiTi influences the adhesive performance of the hybrid system. For samples with a smooth PDMS layer the transition from flat to structured state reduces adhesion by 56%, and for samples with a micropatterned PDMS layer adhesion is switchable by nearly 100%. Both hybrid systems reveal strong reversibility related to the NiTi martensitic phase transformation, allowing repeated switching between an adhesive and a nonadhesive state. These effects have been discussed in terms of reversible changes in contact area and varying tilt angles of the pillars with respect to the substrate surface.

  8. Elastic recoil detection analysis for the determination of hydrogen concentration profiles in switchable mirrors

    NARCIS (Netherlands)

    Huisman, M.C.; van der Molen, S.J.; Vis, R.D.

    1999-01-01

    Switchable mirrors made of thin films of Y, La or rare-earth (RE) metals exhibit spectacular changes in their optical and electrical properties upon hydrogen loading. The study of these materials has indicated that the occurring phenomena are highly sensitive to the actual hydrogen concentration in

  9. Switchable and tunable microwave frequency multiplication based on a dual-passband microwave photonic filter.

    Science.gov (United States)

    Chen, Hao; Xu, Zuowei; Fu, Hongyan; Zhang, Shiwei; Wu, Congxian; Wu, Hao; Xu, Huiying; Cai, Zhiping

    2015-04-20

    In this paper, a novel approach to implement switchable and tunable microwave frequency multiplication has been proposed and experimentally demonstrated. High order harmonics of microwave signal with external modulation technique can be selected by using a novel switchable dual-passband microwave photonic filter (MPF) based on a modified fiber Mach-Zehnder interferometer (FMZI) and a dispersive medium. By adjusting the polarization controllers in the modified FMZI, the passbands of the MPF can switch between lower frequency, higher frequency or dual-passband states, and by changing the length of the variable optical delay line (VODL) in the modified FMZI, the central frequencies of these passbands can also be tuned. Therefore, tunable and switchable microwave signal frequency multiplication can be achieved. The experimental results show that by modulating a driving signal with frequency of 2.5 GHz, a signal with frequency of 7.5 GHz, which is three times of the driving frequency, the other one with the frequency of 15 GHz, which is six times of the driving frequency can be generated and freely switchable between two frequencies and dual frequency states by simply adjusting the polarization controllers in the modified FMZI.

  10. Superstrate-integrated Switchable Beam Rectangular Microstrip Antenna for Gain Enhancement

    Directory of Open Access Journals (Sweden)

    S. Kawdungta

    2017-06-01

    Full Text Available This research has proposed a switchable beam rectangular microstrip antenna with double parasitic patches, in which two PIN diodes were deployed for manipulation of the main beam direction and a superstrate (i.e. either a dielectric slab or metamaterial for enhancement of the antenna gain. The dielectric slab is a second FR4 substrate while the metamaterial (MTM is the 7×17 periodic structure of planar cycloid dipoles (PCD. Simulations were carried out and three different antenna prototypes (i.e. the proposed switchable beam rectangular microstrip antenna, the proposed antenna either with dielectric slab or MTM fabricated and experimented. The simulation and experimental results are in good agreement and exhibit good impedance matching (|S11| less than 10dB along the operating frequency. The average measured gain is 7 dBi with the unidirectional radiation pattern along the operating frequency. The proposed switchable antennas with and without the superstrate are operable in the 2.4-2.5 GHz WLAN system and switchable in three directions of 0 deg, 30 deg and 330 deg (xy-plane. Moreover, the findings validate the applicability of either the dielectric slab or three MTM block-layers as the superstrate to improve the antenna gain.

  11. STIR: Redox-Switchable Olefin Polymerization Catalysis: Electronically Tunable Ligands for Controlled Polymer Synthesis

    Science.gov (United States)

    2013-03-28

    were reduced using standard hydrogenation conditions with hydrogen and palladium on carbon . Though the synthesis of 1,1’-diaminoferrocene has...forward reduction of diimine 7 proved unusually difficult under typical conditions, although a stepwise procedure utilizing formic acid and sodium...REPORT Final Report: STIR: Redox-Switchable Olefin Polymerization Catalysis: Electronically Tunable Ligands for Controlled Polymer Synthesis 14

  12. Construction of a 4 Zeptoliters Switchable 3D DNA Box Origami

    DEFF Research Database (Denmark)

    Zadegan, Reza Mohammad; Jepsen, Mette DE; Thomsen, Karen E

    2012-01-01

    The DNA origami technique is a recently developed self-assembly method that allows construction of 3D objects at the nanoscale for various applications. In the current study we report the production of a 18 × 18 × 24 nm3 hollow DNA box origami structure with a switchable lid. The structure...

  13. Switchable photovoltaic windows enabled by reversible photothermal complex dissociation from methylammonium lead iodide.

    Science.gov (United States)

    Wheeler, Lance M; Moore, David T; Ihly, Rachelle; Stanton, Noah J; Miller, Elisa M; Tenent, Robert C; Blackburn, Jeffrey L; Neale, Nathan R

    2017-11-23

    Materials with switchable absorption properties have been widely used for smart window applications to reduce energy consumption and enhance occupant comfort in buildings. In this work, we combine the benefits of smart windows with energy conversion by producing a photovoltaic device with a switchable absorber layer that dynamically responds to sunlight. Upon illumination, photothermal heating switches the absorber layer-composed of a metal halide perovskite-methylamine complex-from a transparent state (68% visible transmittance) to an absorbing, photovoltaic colored state (less than 3% visible transmittance) due to dissociation of methylamine. After cooling, the methylamine complex is re-formed, returning the absorber layer to the transparent state in which the device acts as a window to visible light. The thermodynamics of switching and performance of the device are described. This work validates a photovoltaic window technology that circumvents the fundamental tradeoff between efficient solar conversion and high visible light transmittance that limits conventional semitransparent PV window designs.

  14. Fast switchable ferroelectric liquid crystal gratings with two electro-optical modes

    International Nuclear Information System (INIS)

    Ma, Ying; Srivastava, A. K.; Chigrinov, V. G.; Kwok, H.-S.; Wang, Xiaoqian

    2016-01-01

    In this article, we reveal a theoretical and experimental illustration of the Ferroelectric liquid crystal (FLC) grating fabricated by mean of patterned alignment based on photo-alignment. The complexity related to the mismatching of the predefined alignment domains on the top and bottom substrate has been avoided by incorporating only one side photo aligned substrate while the other substrate does not have any alignment layer. Depending on the easy axis in the said alignment domains and the azimuth plane of the impinging polarized light, the diffracting element can be tuned in two modes i.e. DIFF/OFF switchable and DIFF/TRANS switchable modes, which can be applied to different applications. The diffraction profile has been illustrated theoretically that fits well with the experimental finding and thus the proposed diffraction elements with fast response time and high diffraction efficiency could find application in many modern devices.

  15. Biphasic Synergistic Gel Materials with Switchable Mechanics and Self-Healing Capacity.

    Science.gov (United States)

    Zhao, Ziguang; Liu, Yuxia; Zhang, Kangjun; Zhuo, Shuyun; Fang, Ruochen; Zhang, Jianqi; Jiang, Lei; Liu, Mingjie

    2017-10-16

    A fabrication strategy for biphasic gels is reported, which incorporates high-internal-phase emulsions. Closely packed micro-inclusions within the elastic hydrogel matrix greatly improve the mechanical properties of the materials. The materials exhibit excellent switchable mechanics and shape-memory performance because of the switchable micro- inclusions that are incorporated into the hydrogel matrix. The produced materials demonstrated a self-healing capacity that originates from the noncovalent effect of the biphasic heteronetwork. The aforementioned characteristics suggest that the biphasic gels may serve as ideal composite gel materials with validity in a variety of applications, such as soft actuators, flexible devices, and biological materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Grafted membranes and substrates having surfaces with switchable superoleophilicity and superoleophobicity and applications thereof

    KAUST Repository

    Zhang, Lianbin

    2013-10-10

    Disclosed herein are surface-modified membranes and other surface-modified substrates exhibiting switchable oleophobicity and oleophilicity in aqueous media. These membranes and substrates may be used for variety of applications, including controllable oil/water separation processes, oil spill cleanup, and oil/water purification. Also provided are the making and processing of such surface-modified membranes and other surface-modified substrates.

  17. Switchable photoluminescence of CdTe nanocrystals by temperature-responsive microgels

    Czech Academy of Sciences Publication Activity Database

    Agrawal, M.; Rubio-Retama, J.; Zafeiropoulos, N. E.; Gaponik, N.; Gupta, S.; Cimrová, Věra; Lesnyak, V.; López-Cabarcos, E.; Tzavalas, S.; Rojas-Reyna, R.; Eychmuller, A.; Stamm, M.

    2008-01-01

    Roč. 24, č. 17 (2008), s. 9820-9824 ISSN 0743-7463 R&D Projects: GA AV ČR IAA4050409; GA MŠk(CZ) 1M06031 Institutional research plan: CEZ:AV0Z40500505 Keywords : switchable photoluminescence * temperature-responsive microgels * CdTe nanocrystals Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.097, year: 2008

  18. Electrically switchable holographic liquid crystal/polymer Fresnel lens using a Michelson interferometer.

    Science.gov (United States)

    Jashnsaz, Hossein; Mohajerani, Ezeddin; Nemati, Hossein; Razavi, Seyed Hossein; Alidokht, Isa Ahmad

    2011-06-10

    A holographic technique for fabricating an electrically switchable liquid crystal/polymer composite Fresnel lens is reported. A Michelson interferometer is used to produce the required Fresnel pattern, by placing a convex lens into one path of the interferometer. Simplicity of the method and the possibility of fabricating different focal length lenses in a single arrangement are advantages of the method. The performance of the fabricated lens was demonstrated and its electro-optical properties were investigated for its primary focal length.

  19. 2004 Survey of United States architects on the subject of switchable glazings

    International Nuclear Information System (INIS)

    Sottile, G.M.

    2005-01-01

    The 21st century has ushered in an era marked by the growing integration of technology and other scientific advances into commercial buildings and residential homes. Of particular interest to many architects, developers and builders are 'switchable' glazing, a new category of technologically advanced glass and plastic building materials that can be used to control light, glare and heat entering an office or a home. Interest in switchable glazing technology is influenced by a variety of factors, including a growing movement to offer sustainable, energy-efficient building solutions, and the emerging desire by users to maintain greater control over their working and living environments. This paper examines the movement toward sustainable development and the end-user needs that are driving it. Further, it presents the results of a proprietary survey research study of United States architects on the subject of switchable glazing. This study includes an examination of the attributes most desired by architects regarding smart window technology, and provides additional insight into the potential application of this smart material to the building community

  20. Switchable polarity solvent for liquid phase microextraction of Cd(II) as pyrrolidinedithiocarbamate chelates from environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, Erkan, E-mail: kimyager_erkan@hotmail.com; Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr

    2015-07-30

    A switchable polarity solvent was synthesized from triethylamine (TEA)/water/CO{sub 2} (Dry ice) via proton transfer reaction has been used for the microextraction of cadmium(II) as pyrrolidinedithiocarbamate (APDC) chelate. Cd(II)-APDC chelate was extracted into the switchable polarity solvent drops by adding 2 mL 10 M sodium hydroxide solution. Analytical parameters affecting the complex formation and microextraction efficiency such as pH, amount of ligand, volume of switchable polarity solvent and NaOH, sample volume were optimized. The effects of foreign ions were found tolerably. Under optimum conditions, the detection limit was 0.16 μg L{sup −1} (3Sb/m, n = 7) and the relative standard deviation was 5.4% (n = 7). The method was validated by the analysis of certified reference materials (TMDA-51.3 fortified water, TMDA-53.3 fortified water and SPS-WW2 waste water, 1573a Tomato Leaves and Oriental Basma Tobacco Leaves (INCT-OBTL-5)) and addition/recovery tests. The method was successfully applied to determination of cadmium contents of water, vegetable, fruit and cigarette samples. - Highlights: • Switchable polarity solvent was synthesized from triethylamine (TEA)/water/CO{sub 2}. • The switchable polarity solvent has been used for the microextraction of cadmium(II). • The important factors were optimized. • The method was applied to determination of cadmium in real samples.

  1. Improved performance of Mg–Y alloy thin film switchable mirrors after coating with a superhydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    La, Mao [Department of Chemistry and Environmental Science, Inner Mongolia Normal University, Hohhot, Inner Mongolia, 010020 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Zhou, Huaijuan; Li, Ning; Xin, Yunchuan [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Sha, Ren, E-mail: sr@imnu.edu.cn [Department of Chemistry and Environmental Science, Inner Mongolia Normal University, Hohhot, Inner Mongolia, 010020 (China); Bao, Shanhu, E-mail: shanhu.bao@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Jin, Ping [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China)

    2017-05-01

    Highlights: • The PTFE films was prepared for use as the top layer of Mg–Y/Pd switchable mirrors. • The PTFE as an antireflection layer to improve the luminous transmission, and also to enhance the switching durability of the switchable mirrors. • The PTFE film has a superhydrophobic surface, which endows the Mg–Y/Pd switchable mirrors with self-cleaning properties. - Abstract: The magnesium based switchable mirrors can reversibly change their optical properties between the transparent and the reflective state as a result of hydrogenation and dehydrogenation. These films can potentially be applied as new energy-saving windows, by controlling the transmittance of solar radiation through the regulation of their reflective state. In this study, magnesium–yttrium (Mg–Y) alloy thin films were prepared using a DC magnetron sputtering method. However, the luminous transmittance in the transparent state and the switching durability of switchable mirrors are too poor to satisfy practical demands. In order to improve the films switching durability, luminous transmittance and the surface functionalization, polytetrafluoroethylene (PTFE) was coated with thermal vacuum deposition for use as the top layer of Mg–Y/Pd switchable mirrors. The PTFE layer had a porous network structure and exhibited a superhydrophobic surface with a water contact angle of approximately 152°. By characterization, PTFE thin films shows the excellent protection role against the oxidization of Mg, the switching durability of the films were improved 3 times, and also shows the antireflection role the luminous transmission of films was enhanced by 7% through the top covered with PTFE.

  2. Switchable reconfiguration of nucleic acid nanostructures by stimuli-responsive DNA machines.

    Science.gov (United States)

    Liu, Xiaoqing; Lu, Chun-Hua; Willner, Itamar

    2014-06-17

    CONSPECTUS: The base sequence in DNA dictates structural and reactivity features of the biopolymer. These properties are implemented to use DNA as a unique material for developing the area of DNA nanotechnology. The design of DNA machines represents a rapidly developing research field in the area of DNA nanotechnology. The present Account discusses the switchable reconfiguration of nucleic acid nanostructures by stimuli-responsive DNA machines, and it highlights potential applications and future perspectives of the area. Programmed switchable DNA machines driven by various fuels and antifuels, such as pH, Hg(2+) ions/cysteine, or nucleic acid strands/antistrands, are described. These include the assembly of DNA tweezers, walkers, a rotor, a pendulum, and more. Using a pH-oscillatory system, the oscillatory mechanical operation of a DNA pendulum is presented. Specifically, the synthesis and "mechanical" properties of interlocked DNA rings are described. This is exemplified with the preparation of interlocked DNA catenanes and a DNA rotaxane. The dynamic fuel-driven reconfiguration of the catenane/rotaxane structures is followed by fluorescence spectroscopy. The use of DNA machines as functional scaffolds to reconfigurate Au nanoparticle assemblies and to switch the fluorescence features within fluorophore/Au nanoparticle conjugates between quenching and surface-enhanced fluorescence states are addressed. Specifically, the fluorescence features of the different DNA machines are characterized as a function of the spatial separation between the fluorophore and Au nanoparticles. The experimental results are supported by theoretical calculations. The future development of reconfigurable stimuli-responsive DNA machines involves fundamental challenges, such as the synthesis of molecular devices exhibiting enhanced complexities, the introduction of new fuels and antifuels, and the integration of new payloads being reconfigured by the molecular devices, such as enzymes or

  3. Conductive Graphitic Carbon Nitride as an Ideal Material for Electrocatalytically Switchable CO2 Capture.

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A; Smith, Sean C

    2015-12-01

    Good electrical conductivity and high electron mobility of the sorbent materials are prerequisite for electrocatalytically switchable CO2 capture. However, no conductive and easily synthetic sorbent materials are available until now. Here, we examined the possibility of conductive graphitic carbon nitride (g-C4N3) nanosheets as sorbent materials for electrocatalytically switchable CO2 capture. Using first-principle calculations, we found that the adsorption energy of CO2 molecules on g-C4N3 nanosheets can be dramatically enhanced by injecting extra electrons into the adsorbent. At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 10(13) cm(-2) or 42.3 wt%. In contrast to other CO2 capture approaches, the process of CO2 capture/release occurs spontaneously without any energy barriers once extra electrons are introduced or removed, and these processes can be simply controlled and reversed by switching on/off the charging voltage. In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2. These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility.

  4. Conductive Graphitic Carbon Nitride as an Ideal Material for Electrocatalytically Switchable CO2 Capture

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A.; Smith, Sean C.

    2015-12-01

    Good electrical conductivity and high electron mobility of the sorbent materials are prerequisite for electrocatalytically switchable CO2 capture. However, no conductive and easily synthetic sorbent materials are available until now. Here, we examined the possibility of conductive graphitic carbon nitride (g-C4N3) nanosheets as sorbent materials for electrocatalytically switchable CO2 capture. Using first-principle calculations, we found that the adsorption energy of CO2 molecules on g-C4N3 nanosheets can be dramatically enhanced by injecting extra electrons into the adsorbent. At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 1013 cm-2 or 42.3 wt%. In contrast to other CO2 capture approaches, the process of CO2 capture/release occurs spontaneously without any energy barriers once extra electrons are introduced or removed, and these processes can be simply controlled and reversed by switching on/off the charging voltage. In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2. These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility.

  5. Borophene as a Promising Material for Charge-Modulated Switchable CO2 Capture.

    Science.gov (United States)

    Tan, Xin; Tahini, Hassan A; Smith, Sean C

    2017-06-14

    Ideal carbon dioxide (CO 2 ) capture materials for practical applications should bind CO 2 molecules neither too weakly to limit good loading kinetics nor too strongly to limit facile release. Although charge-modulated switchable CO 2 capture has been proposed to be a controllable, highly selective, and reversible CO 2 capture strategy, the development of a practical gas-adsorbent material remains a great challenge. In this study, by means of density functional theory (DFT) calculations, we have examined the possibility of conductive borophene nanosheets as promising sorbent materials for charge-modulated switchable CO 2 capture. Our results reveal that the binding strength of CO 2 molecules on negatively charged borophene can be significantly enhanced by injecting extra electrons into the adsorbent. At saturation CO 2 capture coverage, the negatively charged borophene achieves CO 2 capture capacities up to 6.73 × 10 14 cm -2 . In contrast to the other CO 2 capture methods, the CO 2 capture/release processes on negatively charged borophene are reversible with fast kinetics and can be easily controlled via switching on/off the charges carried by borophene nanosheets. Moreover, these negatively charged borophene nanosheets are highly selective for separating CO 2 from mixtures with CH 4 , H 2 , and/or N 2 . This theoretical exploration will provide helpful guidance for identifying experimentally feasible, controllable, highly selective, and high-capacity CO 2 capture materials with ideal thermodynamics and reversibility.

  6. An Ultrafast Switchable Terahertz Polarization Modulator Based on III-V Semiconductor Nanowires.

    Science.gov (United States)

    Baig, Sarwat A; Boland, Jessica L; Damry, Djamshid A; Tan, H Hoe; Jagadish, Chennupati; Joyce, Hannah J; Johnston, Michael B

    2017-04-12

    Progress in the terahertz (THz) region of the electromagnetic spectrum is undergoing major advances, with advanced THz sources and detectors being developed at a rapid pace. Yet, ultrafast THz communication is still to be realized, owing to the lack of practical and effective THz modulators. Here, we present a novel ultrafast active THz polarization modulator based on GaAs semiconductor nanowires arranged in a wire-grid configuration. We utilize an optical pump-terahertz probe spectroscopy system and vary the polarization of the optical pump beam to demonstrate ultrafast THz modulation with a switching time of less than 5 ps and a modulation depth of -8 dB. We achieve an extinction of over 13% and a dynamic range of -9 dB, comparable to microsecond-switchable graphene- and metamaterial-based THz modulators, and surpassing the performance of optically switchable carbon nanotube THz polarizers. We show a broad bandwidth for THz modulation between 0.1 and 4 THz. Thus, this work presents the first THz modulator which combines not only a large modulation depth but also a broad bandwidth and picosecond time resolution for THz intensity and phase modulation, making it an ideal candidate for ultrafast THz communication.

  7. Smart surfaces with switchable superoleophilicity and superoleophobicity in aqueous media: Toward controllable oil/water separation

    KAUST Repository

    Zhang, L.

    2012-02-01

    Advanced materials with surfaces that have controllable oil wettability when submerged in aqueous media have great potential for various underwater applications. Here we have developed smart surfaces on commonly used materials, including non-woven textiles and polyurethane sponges, which are able to switch between superoleophilicity and superoleophobicity in aqueous media. The smart surfaces are obtained by grafting a block copolymer, comprising blocks of pH-responsive poly(2-vinylpyridine) and oleophilic/hydrophobic polydimethylsiloxane (i.e., P2VP-b-PDMS) on these materials. The P2VP block can alter its wettability and its conformation via protonation and deprotonation in response to the pH of the aqueous media, which provides controllable and switchable access of oil by the PDMS block, resulting in the switchable surface oil wettability in the aqueous media. On the other hand, the high flexibility of the PDMS block facilitates the reversible switching of the surface oil wettability. As a proof of concept, we also demonstrate that materials functionalized with our smart surfaces can be used for highly controllable oil/water separation processes.

  8. A Switchable Linker-Based Immunoassay for Ultrasensitive Visible Detection of Salmonella in Tomatoes.

    Science.gov (United States)

    Hahn, Jungwoo; Kim, Eunghee; You, Young Sang; Gunasekaran, Sundaram; Lim, Seokwon; Choi, Young Jin

    2017-10-01

    On-site detection for sensitive identification of foodborne pathogens on fresh produce with minimal use of specialized instrumentation is crucial to the food industry. A switchable linker (SL)-based immunoassay was designed for ultrasensitive on-site detection of Salmonella in tomato samples. The assay is based on large-scale aggregation of gold nanoparticles (GNPs), induced by a quantitative relationship among the biotinylated Salmonella polyclonal antibody (b-Ab) used as the SL, the functionalized GNPs, and Salmonella. Important factors such as the concentration of SLs, time required for large-scale aggregation, and selectivity of b-Ab were optimized to minimize the detection time (within 45 min with gentle agitation) and achieve the lowest limit of detection (LOD; 10 CFU/g in tomato samples) possible. This SL-based immunoassay with its relatively low LOD and short detection time may meet the need for rapid, simple, on-site analysis of pathogens in fresh produce. The novel switchable linker-based immunoassay is a rapid, specific, and sensitive method that has potential applications for routine diagnostics of Salmonella in tomato products. These advantages make it a practical approach for general use in the processing industry to detect Salmonella rapidly and to implement appropriate regulatory procedures. Furthermore, it could be applied to other fresh products including cantaloupe, strawberry, and cucumbers. © 2017 Institute of Food Technologists®.

  9. Conductive Graphitic Carbon Nitride as an Ideal Material for Electrocatalytically Switchable CO2 Capture

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A.; Smith, Sean C.

    2015-01-01

    Good electrical conductivity and high electron mobility of the sorbent materials are prerequisite for electrocatalytically switchable CO2 capture. However, no conductive and easily synthetic sorbent materials are available until now. Here, we examined the possibility of conductive graphitic carbon nitride (g-C4N3) nanosheets as sorbent materials for electrocatalytically switchable CO2 capture. Using first-principle calculations, we found that the adsorption energy of CO2 molecules on g-C4N3 nanosheets can be dramatically enhanced by injecting extra electrons into the adsorbent. At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 1013 cm−2 or 42.3 wt%. In contrast to other CO2 capture approaches, the process of CO2 capture/release occurs spontaneously without any energy barriers once extra electrons are introduced or removed, and these processes can be simply controlled and reversed by switching on/off the charging voltage. In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2. These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility. PMID:26621618

  10. Development and characterization of amorphous acrylate networks for use as switchable adhesives inspired from shapememory behavior

    Science.gov (United States)

    Lakhera, Nishant

    Several types of insects and animals such as spiders and geckos are inherently able to climb along vertical walls and ceilings. This remarkable switchable adhesive behavior has been attributed to the fibrillar structures on their feet, with size ranging from few nanometers to a few micrometers depending on the species. Several studies have attempted to create synthetic micro-patterned surfaces trying to imitate this adhesive behavior seen in nature. The experimental procedures are scattered, with sole purpose of trying to increase adhesion, thereby making direct comparison between studies very difficult. There is a lack of fundamental understanding on adhesion of patterned surfaces. The influence of critical parameters like material modulus, glass transition temperature, viscoelastic effects, temperature and water absorption on adhesion is not fully explored and characterized. These parameters are expected to have a decisive influence on adhesion behavior of the polymer. Previous studies have utilized conventional "off-the-shelf" materials like epoxy, polyurethanes etc. It is however, impossible to change the material modulus, glass transition temperature etc. of these polymer systems without changing the base constituents itself, thereby explaining the gaps in the current research landscape. The purpose of this study was to use acrylate shape-memory polymers (SMPs) for their ability to be tailored to specific mechanical properties by control of polymer chemistry, without changing the base constituents. Polymer networks with tailorable glass transition, material modulus, water absorption etc. were developed and adhesion studies were performed to investigate the influence of temperature, viscoelastic effects, material modulus on the adhesion behavior of flat acrylate polymer surfaces. The knowledge base gained from these studies was utilized to better understand the fundamental mechanisms associated with adhesion behavior of patterned acrylate surfaces. Thermally

  11. Leaf venation, as a resistor, to optimize a switchable IR absorber.

    Science.gov (United States)

    Alston, M E; Barber, R

    2016-08-24

    Leaf vascular patterns are the mechanisms and mechanical support for the transportation of fluidics for photosynthesis and leaf development properties. Vascular hierarchical networks in leaves have far-reaching functions in optimal transport efficiency of functional fluidics. Embedding leaf morphogenesis as a resistor network is significant in the optimization of a translucent thermally functional material. This will enable regulation through pressure equalization by diminishing flow pressure variation. This paper investigates nature's vasculature networks that exhibit hierarchical branching scaling applied to microfluidics. To enable optimum potential for pressure drop regulation by algorithm design. This code analysis of circuit conduit optimization for transport fluidic flow resistance is validated against CFD simulation, within a closed loop network. The paper will propose this self-optimization, characterization by resistance seeking targeting to determine a microfluidic network as a resistor. To advance a thermally function material as a switchable IR absorber.

  12. Rational Design of a Green-Light-Mediated Unimolecular Platform for Fast Switchable Acidic Sensing.

    Science.gov (United States)

    Zhou, Yunyun; Zou, Qi; Qiu, Jing; Wang, Linjun; Zhu, Liangliang

    2018-02-01

    A controllable sensing ability strongly connects to complex and precise events in diagnosis and treatment. However, imposing visible light into the molecular-scale mediation of sensing processes is restricted by the lack of structural relevance. To address this critical challenge, we present the rational design, synthesis, and in vitro studies of a novel cyanostyryl-modified azulene system for green-light-mediated fast switchable acidic sensing. The advantageous features of the design include a highly efficient green-light-driven Z/E-isomerization (a quantum yield up to 61.3%) for fast erasing chromatic and luminescent expressions and a superior compatibility with control of ratiometric protonation. Significantly, these merits of the design enable the development of a microfluidic system to perform a green-light-mediated reusable sensing function toward a gastric acid analyte in a miniaturized platform. The results may provide new insights for building future integrated green materials.

  13. Switchable self-assembly of Prussian blue analogs nano-tiles triggered by salt stimulus.

    Science.gov (United States)

    Dedovets, D; Bauduin, P; Causse, J; Girard, L; Diat, O

    2016-01-28

    Prussian blue analogs (PBAs) are materials well known for their bulk physical and (electro)-chemical properties, with an outstanding selectivity for caesium in ion exchange processes. Crystalline nano-tiles, made of copper based PBA, are produced and dispersed in water by tuning their electrostatic interactions. The shape and size of the nano-crystals are determined by combining scattering, microscopic and spectral techniques. We show here that Cu-PBA nano-tiles form planar superstructures by an edge to edge self-assembly process controlled by specific cation effect and ionic strength. Sedimentation and (re-)dispersion of the nano-tiles are found to be fully reversible. This switchable anisotropic self-assembly triggered by salt stimulus makes PBA nanocrystals potentially interesting for applications.

  14. Hybrid semiconductor-dielectric metamaterial modulation for switchable bi-directional THz absorbers

    Science.gov (United States)

    Le, Ly Nguyen; Thang, Nguyen Manh; Thuy, Le Minh; Tung, Nguyen Thanh

    2017-01-01

    There is an increasing interest for electromagnetic metamaterials that show mutable absorption properties with real-time and dynamic control. In this paper, we investigate a modulation of bi-directional metamaterial absorbers that is thermally switchable at terahertz frequencies. The metamaterial absorber is composed of symmetric hybrid semiconductor-dielectric cut-wire-pair structures, whose electromagnetic responses can be actively manipulated by utilizing an external heat source. As increasing the temperature of metamaterials from 300 to 350 K, we demonstrate that the magnetic resonance can be systematically blue-shifted and overlapped with the electric resonance, which is unaffectedly settled at about 0.8 THz. This superposition provides an effective mechanism to control the absorption intensity from 43% to nearly 95%. Finite integration simulation technique, standard retrieval method, and equivalent circuit model are employed to elaborate our idea.

  15. Sound and Noisy Light: Tuning Phonon Modes in Photo-switchable Nanostructures

    Science.gov (United States)

    Sklan, Sophia; Grossman, Jeffrey

    2014-03-01

    The coupling of light to structural vibrations is well known and results in phenomena like phonon polaritons, acousto-optics (where phonons modulate optical properties), and optomechanics (where light creates or absorbs phonons). Here we consider the question of whether light could also be used to modulate the properties of phonons. We examine photo-isomers (which change their shape under exposure to light), embedded in a nanostructure designed to amplify the effects of photo-switching. To isolate the effects of photo-isomerization (jump photo-switching and shot noise), we apply a combination of analytic and computational techniques to analyze the stochastic dynamics of a toy model of this system. Particular attention is paid to applying this model to explore the potential applications of the photo-switchable nanostructure.

  16. Achieving dynamic switchable filter based on a transmutable metasurface using SMA

    Science.gov (United States)

    Chen, Xin; Gao, Jinsong; Kang, Bonan

    2017-09-01

    We propose a switchable filter composed of transmutable array using shape memory alloys (SMA). It could exhibit a temperature induced morphology change spontaneously like the biological excitability, acting as a shutter that allows the incident energy to be selectively transmitted or reflected with in excess of 12dB isolation at the certain frequencies for both polarizations. Equivalent circuit models describe the operational principle qualitatively and the switching effect is underpinned by the full-wave analysis. A further physical mechanism is shown by contrasting the distributions of electric field and surface current on the surface at the same frequency for the two working modes. The experimental results consist with the theoretical simulations, indicating that the metasurface could serve as one innovative solution for manipulating the electromagnetic waves and enlighten the next generation of advanced electromagnetic materials with more freedom in the processes of design and manufacturing.

  17. Achieving dynamic switchable filter based on a transmutable metasurface using SMA

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2017-09-01

    Full Text Available We propose a switchable filter composed of transmutable array using shape memory alloys (SMA. It could exhibit a temperature induced morphology change spontaneously like the biological excitability, acting as a shutter that allows the incident energy to be selectively transmitted or reflected with in excess of 12dB isolation at the certain frequencies for both polarizations. Equivalent circuit models describe the operational principle qualitatively and the switching effect is underpinned by the full-wave analysis. A further physical mechanism is shown by contrasting the distributions of electric field and surface current on the surface at the same frequency for the two working modes. The experimental results consist with the theoretical simulations, indicating that the metasurface could serve as one innovative solution for manipulating the electromagnetic waves and enlighten the next generation of advanced electromagnetic materials with more freedom in the processes of design and manufacturing.

  18. Switchable diode effect in oxygen vacancy-modulated SrTiO{sub 3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Xinqiang; Shuai, Yao; Wu, Chuangui; Luo, Wenbo; Sun, Xiangyu; Zeng, Huizhong; Bai, Xiaoyuan; Gong, Chaoguan; Jian, Ke; Zhang, Wanli [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, Chengdu (China); Zhang, Lu; Guo, Hongliang [University of Electronic Science and Technology of China, The Center for Robotics, Chengdu (China); Tian, Benlang [26th Institute of China Electronics Technology Group Corporation, Chongqing (China)

    2017-09-15

    SrTiO{sub 3} (STO) single crystal wafer was annealed in vacuum, and co-planar metal-insulator-metal structure of Pt/Ti/STO/Ti/Pt were formed by sputtering Pt/Ti electrodes onto the surface of STO after annealing. The forming-free resistive switching behavior with self-compliance property was observed in the sample. The sample showed switchable diode effect, which is explained by a simple model that redistribution of oxygen vacancies (OVs) under the external electric field results in the formation of n-n{sup +} junction or n{sup +}-n junction (n donated n-type semiconductor; n{sup +} donated heavily doped n-type semiconductor). The self-compliance property is also interpreted by the formation of n-n{sup +}/n{sup +}-n junction caused by the migration of the OVs under the electric field. (orig.)

  19. Surface induces different crystal structures in a room temperature switchable spin crossover compound.

    Science.gov (United States)

    Gentili, Denis; Liscio, Fabiola; Demitri, Nicola; Schäfer, Bernhard; Borgatti, Francesco; Torelli, Piero; Gobaut, Benoit; Panaccione, Giancarlo; Rossi, Giorgio; Degli Esposti, Alessandra; Gazzano, Massimo; Milita, Silvia; Bergenti, Ilaria; Ruani, Giampiero; Šalitroš, Ivan; Ruben, Mario; Cavallini, Massimiliano

    2016-01-07

    We investigated the influence of surfaces in the formation of different crystal structures of a spin crossover compound, namely [Fe(L)2] (LH: (2-(pyrazol-1-yl)-6-(1H-tetrazol-5-yl)pyridine), which is a neutral compound thermally switchable around room temperature. We observed that the surface induces the formation of two different crystal structures, which exhibit opposite spin transitions, i.e. on heating them up to the transition temperature, one polymorph switches from high spin to low spin and the second polymorph switches irreversibly from low spin to high spin. We attributed this inversion to the presence of water molecules H-bonded to the complex tetrazolyl moieties in the crystals. Thin deposits were investigated by means of polarized optical microscopy, atomic force microscopy, X-ray diffraction, X-ray absorption spectroscopy and micro Raman spectroscopy; moreover the analysis of the Raman spectra and the interpretation of spin inversion were supported by DFT calculations.

  20. Reverse engineering of an affinity-switchable molecular interaction characterized by atomic force microscopy single-molecule force spectroscopy.

    Science.gov (United States)

    Anselmetti, Dario; Bartels, Frank Wilco; Becker, Anke; Decker, Björn; Eckel, Rainer; McIntosh, Matthew; Mattay, Jochen; Plattner, Patrik; Ros, Robert; Schäfer, Christian; Sewald, Norbert

    2008-02-19

    Tunable and switchable interaction between molecules is a key for regulation and control of cellular processes. The translation of the underlying physicochemical principles to synthetic and switchable functional entities and molecules that can mimic the corresponding molecular functions is called reverse molecular engineering. We quantitatively investigated autoinducer-regulated DNA-protein interaction in bacterial gene regulation processes with single atomic force microscopy (AFM) molecule force spectroscopy in vitro, and developed an artificial bistable molecular host-guest system that can be controlled and regulated by external signals (UV light exposure and thermal energy). The intermolecular binding functionality (affinity) and its reproducible and reversible switching has been proven by AFM force spectroscopy at the single-molecule level. This affinity-tunable optomechanical switch will allow novel applications with respect to molecular manipulation, nanoscale rewritable molecular memories, and/or artificial ion channels, which will serve for the controlled transport and release of ions and neutral compounds in the future.

  1. Switchable microwave photonic filter between high Q bandpass filter and notch filter with flat passband based on phase modulation.

    Science.gov (United States)

    Yu, Yuan; Xu, Enming; Dong, Jianji; Zhou, Lina; Li, Xiang; Zhang, Xinliang

    2010-11-22

    We propose and demonstrate a novel switchable microwave photonic filter based on phase modulation. Both a microwave high Q bandpass filter and a microwave notch filter with flat passband are achieved respectively. And the switchability between them by tuning the two tunable optical bandpass filters is demonstrated. We also present a theoretical model and analytical expression for the proposed scheme. A frequency response of a high Q bandpass filter with a Q factor of 327 and a rejection ratio of exceeding 42 dB, and a frequency response of a notch filter with flat passband with a rejection ratio exceeding 34 dB are experimentally obtained. The operation frequency of microwave photonic filter is around 20 GHz.

  2. Wavelength switchable flat-top all-fiber comb filter based on a double-loop Mach-Zehnder interferometer.

    Science.gov (United States)

    Luo, Ai-Ping; Luo, Zhi-Chao; Xu, Wen-Cheng; Cui, Hu

    2010-03-15

    A wavelength switchable all-fiber comb filter with flat-top spectral response based on a double-loop Mach-Zehnder (M-Z) interferometer is proposed and demonstrated. The proposed flat-top filter consists of a rotatable polarizer and a double-loop M-Z interferometer composed of two fiber couplers with a polarization controller (PC) in the first loop. In the theoretical analysis, when the second coupler of the M-Z interferometer is a non-3dB one, with proper settings of the polarization state of the input light and the PC, the wavelength switchable comb filter with flat-top passband can be obtained. Theoretical prediction was verified by experimental demonstration. The measured 1 dB bandwidth was 0.51 nm with a channel spacing of 0.98 nm, indicating that the flat-top passband of 1 dB bandwidth extends to about 50% of the comb spacing.

  3. Electronic devices containing switchably conductive silicon oxides as a switching element and methods for production and use thereof

    Science.gov (United States)

    Tour, James M; Yao, Jun; Natelson, Douglas; Zhong, Lin; He, Tao

    2013-11-26

    In various embodiments, electronic devices containing switchably conductive silicon oxide as a switching element are described herein. The electronic devices are two-terminal devices containing a first electrical contact and a second electrical contact in which at least one of the first electrical contact or the second electrical contact is deposed on a substrate to define a gap region therebetween. A switching layer containing a switchably conductive silicon oxide resides in the the gap region between the first electical contact and the second electrical contact. The electronic devices exhibit hysteretic current versus voltage properties, enabling their use in switching and memory applications. Methods for configuring, operating and constructing the electronic devices are also presented herein.

  4. Switchable Diastereoselectivity in the Fluoride Promoted Vinylogous Mukaiyama-Michael Reaction of 2-Trimethylsilyloxyfuran Catalyzed by Crown Ethers

    KAUST Repository

    Della Sala, Giorgio

    2017-05-31

    The fluoride promoted vinylogous Mukaiyama-Michael reaction (VMMR) of 2-trimethylsilyloxyfuran with diverse α,β-unsaturated ketones is described. The TBAF catalyzed VMMR afforded high anti-diastereoselectivity irrespective of the solvents used. The KF/crown ethers catalytic systems proved to be highly efficient in terms of yields and resulted in a highly diastereoselective unprecedented solvent/catalyst switchable reaction. Anti-adducts were obtained as single diastereomers or with excellent diastereoselectivities when benzo-15-crown-5 in CH2Cl2 was employed. On the other hand, high syn-diastereoselectivities (from 76:24 to 96:4) were achieved by employing dicyclohexane-18-crown-6 in toluene. Based on DFT calculations, the catalysts/solvents-dependent switchable diastereoselectivities are proposed to be the result of loose or tight cation-dienolate ion pairs.

  5. Tunable and switchable multi-wavelength erbium-doped fiber laser with highly nonlinear photonic crystal fiber and polarization controllers

    International Nuclear Information System (INIS)

    Liu, X M; Lin, A; Zhao, W; Lu, K Q; Wang, Y S; Zhang, T Y; Chung, Y

    2008-01-01

    We have proposed a novel multi-wavelength erbium-doped fiber laser by using two polarization controllers and a sampled chirped fiber Bragg grating(SC-FBG). On the assistance of SC-FBG, the proposed fiber lasers with excellent stability and uniformity are tunable and switchable by adjusting the polarization controllers. Our laser can stably lase two waves and up to eight waves simultaneously at room temperature

  6. Improved performance of Mg-Y alloy thin film switchable mirrors after coating with a superhydrophobic surface

    Science.gov (United States)

    La, Mao; Zhou, Huaijuan; Li, Ning; Xin, Yunchuan; Sha, Ren; Bao, Shanhu; Jin, Ping

    2017-05-01

    The magnesium based switchable mirrors can reversibly change their optical properties between the transparent and the reflective state as a result of hydrogenation and dehydrogenation. These films can potentially be applied as new energy-saving windows, by controlling the transmittance of solar radiation through the regulation of their reflective state. In this study, magnesium-yttrium (Mg-Y) alloy thin films were prepared using a DC magnetron sputtering method. However, the luminous transmittance in the transparent state and the switching durability of switchable mirrors are too poor to satisfy practical demands. In order to improve the films switching durability, luminous transmittance and the surface functionalization, polytetrafluoroethylene (PTFE) was coated with thermal vacuum deposition for use as the top layer of Mg-Y/Pd switchable mirrors. The PTFE layer had a porous network structure and exhibited a superhydrophobic surface with a water contact angle of approximately 152°. By characterization, PTFE thin films shows the excellent protection role against the oxidization of Mg, the switching durability of the films were improved 3 times, and also shows the antireflection role the luminous transmission of films was enhanced by 7% through the top covered with PTFE.

  7. Blue Light Switchable Bacterial Adhesion as a Key Step toward the Design of Biofilms.

    Science.gov (United States)

    Chen, Fei; Wegner, Seraphine V

    2017-12-15

    The control of where and when bacteria adhere to a substrate is a key step toward controlling the formation and organization in biofilms. This study shows how we engineer bacteria to adhere specifically to substrates with high spatial and temporal control under blue light, but not in the dark, by using photoswitchable interaction between nMag and pMag proteins. For this, we express pMag proteins on the surface of E. coli so that the bacteria can adhere to substrates with immobilized nMag protein under blue light. These adhesions are reversible in the dark and can be repeatedly turned on and off. Further, the number of bacteria that can adhere to the substrate as well as the attachment and detachment dynamics are adjustable by using different point mutants of pMag and altering light intensity. Overall, the blue light switchable bacteria adhesions offer reversible, tunable and bioorthogonal control with exceptional spatial and temporal resolution. This enables us to pattern bacteria on substrates with great flexibility.

  8. Charge-controlled switchable CO adsorption on FeN4 cluster embedded in graphene

    Science.gov (United States)

    Omidvar, Akbar

    2018-02-01

    Electrical charging of an FeN4 cluster embedded in graphene (FeN4G) is proposed as an approach for electrocatalytically switchable carbon monoxide (CO) adsorption. Using density functional theory (DFT), we found that the CO molecule is strongly adsorbed on the uncharged FeN4G cluster. Our results show that the adsorption energy of a CO molecule on the FeN4G cluster is dramatically decreased by introducing extra electrons into the cluster. Once the charges are removed, the CO molecule is spontaneously adsorbed on the FeN4G absorbent. In the framework of frontier molecular orbital (FMO) analysis, the enhanced sensitivity and reactivity of the FeN4G cluster towards the CO molecule can be interpreted in terms of interaction between the HOMO of CO molecule and the LUMO of FeN4G cluster. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Our study indicates that the FeN4G nanomaterial is an excellent absorbent for controllable and reversible capture and release of the CO.

  9. A Planar UWB Antenna with Switchable Single/Double Band-Rejection Characteristics

    Directory of Open Access Journals (Sweden)

    V. Sharbati

    2016-09-01

    Full Text Available In this Paper, a reconfigurable antenna with capability to operate in the ultrawideband (UWB mode from 2.85 to 14.4 GHz with switchable notch bands of 3.25–4.26 GHz, 5.1–5.9 GHz or 7.1-7.8 GHz, is presented. The proposed antenna has a simple configuration and compact size of 17 × 14 mm2. To make the band-notches, three methods (methods of slot antenna, parasitic patches and backplane structure are used. To achieve the reconfigurability, three PIN diode are placed on the proposed antenna. A PIN diode is inserted over the L-shaped parasitic element and the rectangular patch, another one is placed between the two parasitic elements on the ground plane, and other across the square ring-shaped slot, respectively. Antenna performance can be changed by adjusting the status of the PIN diodes that make the band-notches in applications bands (WLAN, WiMAX/C-band and X-band. Good group delay and monopole-like radiation pattern characteristics are achieved in the frequency band of interest. The antenna performance both by simulation and by experiment indicates that it is suitable and a good candidate for UWB applications.

  10. Switchable Induced Polarization in LaAlO3/SrTiO3 Heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Bark, C [University of Wisconsin, Madison; Sharma, P. [University of Nebraska; Wang, Y. [University of Nebraska; Baek, Seung Hyub [University of Wisconsin, Madison; Lee, S. [University of Wisconsin, Madison; Ryu, S. [University of Wisconsin, Madison; Folkman, C H [University of Wisconsin; Paudel, Tula R [ORNL; Kumar, Amit [ORNL; Kalinin, Sergei V [ORNL; Sokolov, A. [University of Nebraska; Tsymbal, E Y [University of Nebraska, Lincoln; Rzchowski, M [University of Wisconsin; Gruverman, Alexei [ORNL; Eom, Professor Chang-Beom [University of Wisconsin, Madison

    2012-01-01

    Demonstration of a tunable conductivity of the LaAlO3/SrTiO3 interfaces drew significant attention to the development of oxide electronic structures where electronic confinement can be reduced to the nanometer range. While the mechanisms for the conductivity modulation are quite different and include metal insulator phase transition and surface charge writing, generally it is implied that this effect is a result of electrical modification of the LaAlO3 surface (either due to electrochemical dissociation of surface adsorbates or free charge deposition) leading to the change in the twodimensional electron gas (2DEG) density at the LaAlO3/SrTiO3 (LAO/STO) interface. In this paper, using piezoresponse force microscopy we demonstrate a switchable electromechanical response of the LAO overlayer, which we attribute to the motion of oxygen vacancies through the LAO layer thickness. These electrically induced reversible changes in bulk stoichiometry of the LAO layer are a signature of a possible additional mechanism for nanoscale oxide 2DEG control on LAO/STO interfaces.

  11. Durability of switchable QR code carriers under hydrolytic and photolytic conditions

    Science.gov (United States)

    Ecker, Melanie; Pretsch, Thorsten

    2013-09-01

    Following a guest diffusion approach, the surface of a shape memory poly(ester urethane) (PEU) was either black or blue colored. Bowtie-shaped quick response (QR) code carriers were then obtained from laser engraving and cutting, before thermo-mechanical functionalization (programming) was applied to stabilize the PEU in a thermo-responsive (switchable) state. The stability of the dye within the polymer surface and long-term functionality of the polymer were investigated against UVA and hydrolytic ageing. Spectrophotometric investigations verified UVA ageing-related color shifts from black to yellow-brownish and blue to petrol-greenish whereas hydrolytically aged samples changed from black to greenish and blue to light blue. In the case of UVA ageing, color changes were accompanied by dye decolorization, whereas hydrolytic ageing led to contrast declines due to dye diffusion. The Michelson contrast could be identified as an effective tool to follow ageing-related contrast changes between surface-dyed and laser-ablated (undyed) polymer regions. As soon as the Michelson contrast fell below a crucial value of 0.1 due to ageing, the QR code was no longer decipherable with a scanning device. Remarkably, the PEU information carrier base material could even then be adequately fixed and recovered. Hence, the surface contrast turned out to be the decisive parameter for QR code carrier applicability.

  12. Switchable thulium-doped fiber laser from polarization rotation vector to scalar soliton.

    Science.gov (United States)

    Wu, Zhichao; Fu, Songnian; Jiang, Kai; Song, Jue; Li, Huizi; Tang, Ming; Shum, Ping; Liu, Deming

    2016-10-06

    We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect. The scalar solitons and PRLVSs possess 3-dB optical spectrum bandwidth of 2.2 nm and 2 nm, pulse-width of 1.8 ps and 2 ps, respectively. Moreover, the PRLVSs demonstrate a typical energy exchange between two polarized components on optical spectra and a period-doubling feature in time domain. Such operation principle can also be used in 1550 nm band fiber lasers and other nonlinear systems.

  13. Durability of switchable QR code carriers under hydrolytic and photolytic conditions

    International Nuclear Information System (INIS)

    Ecker, Melanie; Pretsch, Thorsten

    2013-01-01

    Following a guest diffusion approach, the surface of a shape memory poly(ester urethane) (PEU) was either black or blue colored. Bowtie-shaped quick response (QR) code carriers were then obtained from laser engraving and cutting, before thermo-mechanical functionalization (programming) was applied to stabilize the PEU in a thermo-responsive (switchable) state. The stability of the dye within the polymer surface and long-term functionality of the polymer were investigated against UVA and hydrolytic ageing. Spectrophotometric investigations verified UVA ageing-related color shifts from black to yellow-brownish and blue to petrol-greenish whereas hydrolytically aged samples changed from black to greenish and blue to light blue. In the case of UVA ageing, color changes were accompanied by dye decolorization, whereas hydrolytic ageing led to contrast declines due to dye diffusion. The Michelson contrast could be identified as an effective tool to follow ageing-related contrast changes between surface-dyed and laser-ablated (undyed) polymer regions. As soon as the Michelson contrast fell below a crucial value of 0.1 due to ageing, the QR code was no longer decipherable with a scanning device. Remarkably, the PEU information carrier base material could even then be adequately fixed and recovered. Hence, the surface contrast turned out to be the decisive parameter for QR code carrier applicability. (paper)

  14. Size Switchable Supramolecular Nanoparticle Based on Azobenzene Derivative within Anionic Pillar[5]arene

    Science.gov (United States)

    Zhang, Cai-Cai; Li, Sheng-Hua; Zhang, Cui-Fang; Liu, Yu

    2016-11-01

    A photo/thermal-switchable supramolecular nanoparticles assembly has been constructed based on an inclusion complex between anionic pillar[5]arene 2C-WP5A and azobenzene derivative Azo-py-OMe (G). The novel anionic pillar[5]arene-based host-guest inclusion complexation was investigated by the 1H NMR titration, 2D ROESY and isothermal titration microcalorimetry (ITC) showing high association constant (Ka) of (2.60 ± 0.06) × 104 M-1 with 1:1 binding stoichiometry. Furthermore, the supramolecular nanoparticles assembly can be conveniently obtained from G and a small amount of 2C-WP5A in aqueous solution, which was so-called “host induced aggregating (HIA)”. The size and morphology of the supramolecular nanoparticles assembly were characterized by TEM and DLS. As a result of the photo/thermal-isomerization of G included in the cavity of 2C-WP5A, the size of these nanoparticles could reversibly change from ~800 nm to ~250 nm, which could switch the solution of this assembly from turbid to clear.

  15. Enhanced Switchable Ferroelectric Photovoltaic Effects in Hexagonal Ferrite Thin Films via Strain Engineering.

    Science.gov (United States)

    Han, Hyeon; Kim, Donghoon; Chu, Kanghyun; Park, Jucheol; Nam, Sang Yeol; Heo, Seungyang; Yang, Chan-Ho; Jang, Hyun Myung

    2018-01-17

    Ferroelectric photovoltaics (FPVs) are being extensively investigated by virtue of switchable photovoltaic responses and anomalously high photovoltages of ∼10 4 V. However, FPVs suffer from extremely low photocurrents due to their wide band gaps (E g ). Here, we present a promising FPV based on hexagonal YbFeO 3 (h-YbFO) thin-film heterostructure by exploiting its narrow E g . More importantly, we demonstrate enhanced FPV effects by suitably exploiting the substrate-induced film strain in these h-YbFO-based photovoltaics. A compressive-strained h-YbFO/Pt/MgO heterojunction device shows ∼3 times enhanced photovoltaic efficiency than that of a tensile-strained h-YbFO/Pt/Al 2 O 3 device. We have shown that the enhanced photovoltaic efficiency mainly stems from the enhanced photon absorption over a wide range of the photon energy, coupled with the enhanced polarization under a compressive strain. Density functional theory studies indicate that the compressive strain reduces E g substantially and enhances the strength of d-d transitions. This study will set a new standard for determining substrates toward thin-film photovoltaics and optoelectronic devices.

  16. Charge Modulation in Graphitic Carbon Nitride as a Switchable Approach to High-Capacity Hydrogen Storage.

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A; Smith, Sean C

    2015-11-01

    Electrical charging of graphitic carbon nitride nanosheets (g-C4 N3 and g-C3 N4 ) is proposed as a strategy for high-capacity and electrocatalytically switchable hydrogen storage. Using first-principle calculations, we found that the adsorption energy of H2 molecules on graphitic carbon nitride nanosheets is dramatically enhanced by injecting extra electrons into the adsorbent. At full hydrogen coverage, the negatively charged graphitic carbon nitride achieves storage capacities up to 6-7 wt %. In contrast to other hydrogen storage approaches, the storage/release occurs spontaneously once extra electrons are introduced or removed, and these processes can be simply controlled by switching on/off the charging voltage. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Importantly, g-C4 N3 has good electrical conductivity and high electron mobility, which can be a very good candidate for electron injection/release. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Mechanically switchable solid inhomogeneous phantom for performance tests in diffuse imaging and spectroscopy.

    Science.gov (United States)

    Pifferi, Antonio; Torricelli, Alessandro; Cubeddu, Rinaldo; Quarto, Giovanna; Re, Rebecca; Sekar, Sanathana K V; Spinelli, Lorenzo; Farina, Andrea; Martelli, Fabrizio; Wabnitz, Heidrun

    2015-12-01

    A mechanically switchable solid inhomogeneous phantom simulating localized absorption changes was developed and characterized. The homogeneous host phantom was made of epoxy resin with black toner and titanium dioxide particles added as absorbing and scattering components, respectively. A cylindrical rod, movable along a hole in the block and made of the same material, has a black polyvinyl chloride cylinder embedded in its center. By varying the volume and position of the black inclusion, absorption perturbations can be generated over a large range of magnitudes. The phantom has been characterized by various time-domain diffuse optics instruments in terms of absorption and scattering spectra, transmittance images, and reflectance contrast. Addressing a major application of the phantom for performance characterization for functional near-infrared spectroscopy of the brain, the contrast was measured in reflectance mode while black cylinders of volumes from ≈20  mm3 to ≈270  mm3 were moved in lateral and depth directions, respectively. The new type of solid inhomogeneous phantom is expected to become a useful tool for routine quality check of clinical instruments or implementation of industrial standards provided an experimental characterization of the phantom is performed in advance.

  18. Monochromatic and electrochemically switchable electrochemiluminescence of perovskite CsPbBr3 nanocrystals.

    Science.gov (United States)

    Huang, Yan; Fang, Mingxiang; Zou, Guizheng; Zhang, Bin; Wang, Huaisheng

    2016-11-10

    Cubic-shaped perovskite CsPbBr 3 nanocrystals (NCs) could be electrochemically injected with holes (or electrons) to produce several charged states under different oxidizing and reducing potentials, and then bring out electrochemiluminescence (ECL) of higher color purity than traditional ECL chemicals and metal chalcogenide NCs, in both annihilation and co-reactant routes. The difference of electrochemical gaps between varied hole and electron injecting potentials displayed little effect on the ECL spectrum and colour purity of CsPbBr 3 NCs. All the excited states generated under different oxidizing and reducing potential couples in ECL of CsPbBr 3 NCs were the same as those in photoluminescence, as all the ECL spectra were almost identical to the CsPbBr 3 NCs' photoluminescence spectrum. Importantly, the ECL of CsPbBr 3 NCs was electrochemically switchable and displayed an obvious "on/off" type feature by changing the sequence of hole injecting and electron injecting processes, as strong ECL could be obtained by injecting holes onto the electron injected NCs, while no or very weak ECL was obtained in the reversed way.

  19. Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

    Directory of Open Access Journals (Sweden)

    Florian Hamon

    2014-12-01

    Full Text Available This paper reports an efficient preparation of bridged bis-β-CD AZO-CDim 1 bearing azobenzene as a linker and exhibiting high solubility in water. The photoisomerization properties were studied by UV–vis and HPLC and supported by ab initio calculations. The cis/trans ratio of AZO-CDim 1 is 7:93 without irradiation and 37:63 after 120 min of irradiation at 365 nm; the reaction is reversible after irradiation at 254 nm. The photoinduced, switchable binding behavior of AZO-CDim 1 was evaluated by ITC, NMR and molecular modeling in the presence of a ditopic adamantyl guest. The results indicate that AZO-CDim 1 can form two different inclusion complexes with an adamantyl dimer depending on its photoinduced isomers. Both cavities of cis-AZO-CDim 1 are complexed simultaneously by two adamantyl units of the guest forming a 1:1 complex while trans-AZO-CDim 1 seems to lead to the formation of supramolecular polymers with an n:n stoichiometry.

  20. Tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser based on nonlinear polarization rotation

    International Nuclear Information System (INIS)

    Luo, A-P; Luo, Z-C; Xu, W-C; Dvoyrin, V V; Mashinsky, V M; Dianov, E M

    2011-01-01

    We demonstrate a tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser by using nonlinear polarization rotation (NPR) technique. Exploiting the spectral filtering effect caused by the combination of the polarizer and intracavity birefringence, the wavelength separation of dual-wavelength mode-locked pulses can be flexibly tuned between 2.38 and 20.45 nm. Taking the advantage of NPR-induced intensity-dependent loss to suppress the mode competition, the stable dual-wavelength pulses output is obtained at room temperature. Moreover, the dual-wavelength switchable operation is achieved by simply rotating the polarization controllers (PCs)

  1. Conductive Boron-Doped Graphene as an Ideal Material for Electrocatalytically Switchable and High-Capacity Hydrogen Storage.

    Science.gov (United States)

    Tan, Xin; Tahini, Hassan A; Smith, Sean C

    2016-12-07

    Electrocatalytic, switchable hydrogen storage promises both tunable kinetics and facile reversibility without the need for specific catalysts. The feasibility of this approach relies on having materials that are easy to synthesize, possessing good electrical conductivities. Graphitic carbon nitride (g-C 4 N 3 ) has been predicted to display charge-responsive binding with molecular hydrogen-the only such conductive sorbent material that has been discovered to date. As yet, however, this conductive variant of graphitic carbon nitride is not readily synthesized by scalable methods. Here, we examine the possibility of conductive and easily synthesized boron-doped graphene nanosheets (B-doped graphene) as sorbent materials for practical applications of electrocatalytically switchable hydrogen storage. Using first-principle calculations, we find that the adsorption energy of H 2 molecules on B-doped graphene can be dramatically enhanced by removing electrons from and thereby positively charging the adsorbent. Thus, by controlling charge injected or depleted from the adsorbent, one can effectively tune the storage/release processes which occur spontaneously without any energy barriers. At full hydrogen coverage, the positively charged BC 5 achieves high storage capacities up to 5.3 wt %. Importantly, B-doped graphene, such as BC 49 , BC 7 , and BC 5 , have good electrical conductivity and can be easily synthesized by scalable methods, which positions this class of material as a very good candidate for charge injection/release. These predictions pave the route for practical implementation of electrocatalytic systems with switchable storage/release capacities that offer high capacity for hydrogen storage.

  2. A Switchable Molecular Dielectric with Two Sequential Reversible Phase Transitions: [(CH3)4P]4[Mn(SCN)6].

    Science.gov (United States)

    Li, Qiang; Shi, Ping-Ping; Ye, Qiong; Wang, Hui-Ting; Wu, De-Hong; Ye, Heng-Yun; Fu, Da-Wei; Zhang, Yi

    2015-11-16

    A new organic-inorganic hybrid switchable and tunable dielectric compound, [(CH3)4P]4[Mn(SCN)6] (1), exhibits three distinct dielectric states above room temperature and undergoes two reversible solid-state phase transitions, including a structural phase transition at 330 K and a ferroelastic phase transition with the Aizu notation of mmmF2/m at 352 K. The variable-temperature structural analyses disclose that the origin of the phase transitions and dielectric anomalies can be ascribed to the reorientation or motion of both the [(CH3)4P](+) cations and [Mn(SCN)6](4-) anions in solid-state crystals.

  3. A Planar Switchable 3-D-Coverage Phased Array Antenna and Its User Effects for 28-GHz Mobile Terminal Applications

    DEFF Research Database (Denmark)

    Zhang, Shuai; Chen, Xiaoming; Syrytsin, Igor A.

    2017-01-01

    This paper introduces a planar switchable 3D-coverage phased array for 28 GHz mobile terminal applications. In order to realize 3D-coverage beam scan with a simple planar array, chassis surface waves are efficiently excited and controlled by three identical slot subarrays. Three subarrays switch...... their beams to three distinct regions. Each subarray works as a phased array to steer the beam within each region. Large coverage efficiency is achieved (e.g., 80% of the space sphere has the realized gain of over 8 dBi). The proposed antenna covers a bandwidth of over 2 GHz in the band of 28 GHz. User...

  4. Gallium Adhesion: Phase Change of Gallium Enables Highly Reversible and Switchable Adhesion (Adv. Mater. 25/2016).

    Science.gov (United States)

    Ye, Zhou; Lum, Guo Zhan; Song, Sukho; Rich, Steven; Sitti, Metin

    2016-07-01

    M. Sitti and co-workers find that gallium exhibits highly reversible and switchable adhesive characteristics during the liquid-solid phase change. As described on page 5088, this reversible adhesive allows miniature capsule-like robots, which are able to easily pick-and-place objects with irregular geometries and rough surfaces, and thus assemble such objects into a complex structure. The contact interface between gallium and the rough object is illustrated in the magnified image. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Switchable zipper-like thermoresponsive molecularly imprinted polymers for selective recognition and extraction of estradiol.

    Science.gov (United States)

    Xiong, Huihuang; Wu, Xiaqing; Lu, Wenhui; Fu, Junqing; Peng, Hailong; Li, Jinhua; Wang, Xiaoyan; Xiong, Hua; Chen, Lingxin

    2018-01-01

    Zipper-like thermoresponsive molecularly imprinted polymers (MIPs) were prepared based on interpolymer complexation via the synergy of dual functional monomers of acrylamide (AAm) and 2-acrylamide-2-methyl propanesulfonic acid (AMPS) for selective recognition and extraction of estradiol (E2) by temperature regulation. The resulting E2-MIPs attained controlled adsorption and release of E2 in response to temperature change, with higher adsorption capacity (8.78mg/g) and stronger selectivity (imprinting factor was 3.18) at 30°C compared with that at 20 and 40°C; the zipper-like interpolymer interaction between poly(AAm) and poly(AMPS) enabled switchable molecular recognition. The adsorption processes obeyed Langmuir isotherm and pseudo-second-order kinetic models. High recognition selectivity of the MIPs toward E2 was achieved over its structural analogues, and good reusability was displayed over 86% recovery after six adsorption-desorption cycles. Accordingly, the E2-MIPs were empolyed as new adsorbents for selective dispersive solid-phase extraction of E2, and offered low limits of detection and quantification of 4.81 and 16.03μg/L, respectively. Recoveries from goat milk samples ranged from 76.2% to 89.7% with the precisions (relative standard deviations, n = 3, %) of 2.8-3.7% at 30°C. The intelligent E2-MIPs combining good adsorption, special recognition and temperature sensitivity proved to be a promising alternative to the selective identification and controlled extraction/removal of E2 in complicated samples by simple temperature-responsive regulation. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Trapping of quantum particles and light beams by switchable potential wells

    Science.gov (United States)

    Sonkin, Eduard; Malomed, Boris A.; Granot, Er'El; Marchewka, Avi

    2010-09-01

    We consider basic dynamical effects in settings based on a pair of local potential traps that may be effectively switched on and off, or suddenly displaced, by means of appropriate control mechanisms, such as scanning tunneling microscopy or photo-switchable quantum dots. The same models, based on the linear Schrödinger equation with time-dependent trapping potentials, apply to the description of optical planar systems designed for the switching of trapped light beams. The analysis is carried out in the analytical form, using exact solutions of the Schrödinger equation. The first dynamical problem considered in this work is the retention of a particle released from a trap which was suddenly turned off, while another local trap was switched on at a distance—immediately or with a delay. In this case, we demonstrate that the maximum of the retention rate is achieved at a specific finite value of the strength of the new trap, and at a finite value of the temporal delay, depending on the distance between the two traps. Another problem is retrapping of the bound particle when the addition of the second trap transforms the single-well setting into a double-well potential (DWP). In that case, we find probabilities for the retrapping into the ground or first excited state of the DWP. We also analyze effects entailed by the application of a kick to a bound particle, the most interesting one being a kick-induced transition between the DWP’s ground and excited states. In the latter case, the largest transition probability is achieved at a particular strength of the kick.

  7. Virtual screening on an α-helix to β-strand switchable region of the FGFR2 extracellular domain revealed positive and negative modulators.

    Science.gov (United States)

    Diaz, Constantino; Corentin, Herbert; Thierry, Vermat; Chantal, Alcouffe; Tanguy, Bozec; David, Sibrac; Jean-Marc, Herbert; Pascual, Ferrara; Françoise, Bono; Edgardo, Ferran

    2014-11-01

    The secondary structure of some protein segments may vary between α-helix and β-strand. To predict these switchable segments, we have developed an algorithm, Switch-P, based solely on the protein sequence. This algorithm was used on the extracellular parts of FGF receptors. For FGFR2, it predicted that β4 and β5 strands of the third Ig-like domain were highly switchable. These two strands possess a high number of somatic mutations associated with cancer. Analysis of PDB structures of FGF receptors confirmed the switchability prediction for β5. We thus evaluated if compound-driven α-helix/β-strand switching of β5 could modulate FGFR2 signaling. We performed the virtual screening of a library containing 1.4 million of chemical compounds with two models of the third Ig-like domain of FGFR2 showing different secondary structures for β5, and we selected 32 compounds. Experimental testing using proliferation assays with FGF7-stimulated SNU-16 cells and a FGFR2-dependent Erk1/2 phosphorylation assay with FGFR2-transfected L6 cells, revealed activators and inhibitors of FGFR2. Our method for the identification of switchable proteinic regions, associated with our virtual screening approach, provides an opportunity to discover new generation of drugs with under-explored mechanism of action. © 2014 Wiley Periodicals, Inc.

  8. Photonic Crystals: Enhancing the Light Output of Scintillation Based Detectors

    CERN Document Server

    Knapitsch, Arno Richard

    A scintillator is a material which emits light when excited by ionizing radiation. Such materials are used in a diverse range of applications; From high energy particle physics experiments, X-ray security, to nuclear cameras or positron emission tomography. Future high-energy physics (HEP) experiments as well as next generation medical imaging applications are more and more pushing towards better scintillation characteristics. One of the problems in heavy scintillating materials is related to their high index of refraction. As a consequence, most of the scintillation light produced in the bulk material is trapped inside the crystal due to total internal reflection. The same problem also occurs with light emitting diodes (LEDs) and has for a long time been considered as a limiting factor for their overall efficiency. Recent developments in the area of nanophotonics were showing now that those limitations can be overcome by introducing a photonic crystal (PhC) slab at the outcoupling surface of the substrate. P...

  9. Light output enhancement for a plastic scintillator using nanofibers

    Science.gov (United States)

    Cheng, Zhangkai J.; Blake, Samuel J.; Vial, Phil; Lu, Ming; Kuncic, Zdenka; Atakaramians, Shaghik

    2017-08-01

    Electronic portal imaging devices (EPIDs) are x-ray detector systems conventionally used for medical imaging applications in cancer radiotherapy. Our group has developed a novel prototype EPID with the unique capability of performing both imaging and dose measurements. Our prototype utilizes an array of plastic scintillating fibers in place of the standard copper and gadolinium dioxysulfide phosphor components1. While our prototype EPID exhibits a detective quantum efficiency that exceeds that of commercial products, there is further scope for improvement. In particular, there is scope to improve optical coupling between the scintillating fiber array and the underlying photodetector where currently an air gap exists. Here, we investigate the effect of a layer of polystyrene nanofibers placed at the end interface of the scintillator array on light extraction efficiency using finite element modelling. We demonstrate that the total light extraction, which depends on the polarization of the incident light, can be enhanced by up to 14%. This enhancement stems from two effects: Bragg diffraction arising from the periodic arrangement of the fibers and Whispering Gallery Modes (WGMs) formed at each fiber's cross-section due to Mie resonances. We show that the nanofibers increase optical transmittance above the critical angle. Moreover, we demonstrate that the light extraction efficiency strongly depends on the polarization of the incident light (s- and p-polarizations), as well as the diameter and periodicity of the nanofibers.

  10. Smart candle soot coated membranes for on-demand immiscible oil/water mixture and emulsion switchable separation.

    Science.gov (United States)

    Li, Jian; Zhao, Zhihong; Li, Dianming; Tian, Haifeng; Zha, Fei; Feng, Hua; Guo, Lin

    2017-09-21

    Oil/water separation is of great importance for the treatment of oily wastewater, including immiscible light/heavy oil-water mixtures, oil-in-water or water-in-oil emulsions. Smart surfaces with responsive wettability have received extensive attention especially for controllable oil/water separation. However, traditional smart membranes with a switchable wettability between superhydrophobicity and superhydrophilicity are limited to certain responsive materials and continuous external stimuli, such as pH, electrical field or light irradiation. Herein, a candle soot coated mesh (CSM) with a larger pore size and a candle soot coated PVDF membrane (CSP) with a smaller pore size with underwater superoleophobicity and underoil superhydrophobicity were successfully fabricated, which can be used for on-demand immiscible oil/water mixtures and surfactants-stabilized oil/water emulsion separation, respectively. Without any continuous external stimulus, the wettability of our membranes could be reversibly switched between underwater superoleophobicity and underoil superhydrophobicity simply by drying and washing alternately, thus achieving effective and switchable oil/water separation with excellent separation efficiency. We believe that such smart materials will be promising candidates for use in the removal of oil pollutants in the future.

  11. Mechanism(s) for the suppression of the switchable polarization in PZT and BaTiO3

    Science.gov (United States)

    Warren, William L.; Dimos, Duane; Tuttle, Bruce A.; Pike, Gordon E.; Raymond, Mark V.; Nasby, Robert D.; Ramesh, R.; Evans, Joseph T., Jr.

    Switchable polarization can be significantly suppressed in ferroelectric (FE) materials by optical, thermal, and electrical processes. The thermal process can occur by either annealing the FE in a reducing environment or by heating it in air to 100 C while impressing a bias near the switching threshold. The optical process occurs while biasing the FE near the switching threshold and illuminating with bandgap light. And the electrical suppression effect occurs by subjecting the FE to repeated polarization reversals. Using electron paramagnetic resonance, polarization-voltage measurements, and charge injection scenarios, the authors have been able to elucidate both electronic and ionic trapping effects that lead to a suppression in the amount of switchable polarization in FE materials. The relative roles of electronic and ionic effects in the same material can depend on the stress condition. For instance, in oxidized BaTiO3 crystals, optical and thermal suppressions occur by electronic domain pinning; electrical fatigue in the BaTiO3 crystals also appears to involve electronic charge trapping, however, it is suggested that these electronic traps are further stabilized by nearby ionic defects. In sol-gel PZT thin films with either Pt, RuO2, or La-Sr-Co-O electrodes it appears that the polarization suppression induced by electrical fatigue, a temperature/bias combination, or a light/bias combination are all primarily due to the trapping of electronic charge carriers to first order.

  12. Reversed thermo-switchable molecular sieving membranes composed of two-dimensional metal-organic nanosheets for gas separation.

    Science.gov (United States)

    Wang, Xuerui; Chi, Chenglong; Zhang, Kang; Qian, Yuhong; Gupta, Krishna M; Kang, Zixi; Jiang, Jianwen; Zhao, Dan

    2017-02-16

    It is highly desirable to reduce the membrane thickness in order to maximize the throughput and break the trade-off limitation for membrane-based gas separation. Two-dimensional membranes composed of atomic-thick graphene or graphene oxide nanosheets have gas transport pathways that are at least three orders of magnitude higher than the membrane thickness, leading to reduced gas permeation flux and impaired separation throughput. Here we present nm-thick molecular sieving membranes composed of porous two-dimensional metal-organic nanosheets. These membranes possess pore openings parallel to gas concentration gradient allowing high gas permeation flux and high selectivity, which are proven by both experiment and molecular dynamics simulation. Furthermore, the gas transport pathways of these membranes exhibit a reversed thermo-switchable feature, which is attributed to the molecular flexibility of the building metal-organic nanosheets.

  13. Thermally switchable meta-material absorber involving vanadium dioxide semiconductor–metal transition for thermo photovoltaic conversion

    Science.gov (United States)

    Bendelala, Fathi; Cheknane, Ali; Hilal, Hikmat S.

    2018-01-01

    A new switchable absorber design using meta-materials for thermo photovoltaic applications is proposed here. Conventional absorbents are normally non-adjustable with narrow band-widths and polarization-dependence. The present study describes an alternative infrared absorber structure with tunable characteristics. The absorber is based on VO2 which exhibits transition from semiconductor to metallic conductor by thermal effect. With this design, the results show that wide-band absorption can be achieved. The absorption bandwidth can be improved from 15.94 to 36.75 THz. With 40.42% relative shift in the peak frequency, a maximum absorption efficiency of 99% can be achieved. This structure design is polarization-independent of normal incident radiations, and may accommodate radiations from wide oblique angles. These new features make the new thermally adjustable absorber potentially useful in thermo-photovoltaic conversion devices.

  14. Fluoropolymer/SiO2 composite films with switchable superoleophilicity and high oleophobicity for “on–off” oil permeation

    International Nuclear Information System (INIS)

    Yang, Hao; Hu, Xiaojing; Chen, Rong; Liu, Shantang; Pi, Pihui; Yang, Zhuo-ru

    2013-01-01

    In this work, fluoropolymer/SiO 2 composite films with switchable superoleophilicity and high oleophobicity have been successfully prepared on stainless steel mesh. Tunable wettability could be easily realized by merely reversing the feeding order of the perfluorinated monomer in the polymerization. The effects of surface roughness and chemical composition on the wettability of the films were investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results indicate that the distribution of low surface energy groups plays a crucial role in determining the surface oleophobicity or oleophilicity. The porous stainless steel mesh with fluoropolymer/SiO 2 composite could construct dual-scale roughness, leading to less wetting of the solid. The stainless steel mesh coated with the proposed as-prepared polymer films may lead to an oil–water separation membrane. This work provides an interesting insight into the design of novel functional devices that are relevant to oil/water separation.

  15. Reversed thermo-switchable molecular sieving membranes composed of two-dimensional metal-organic nanosheets for gas separation

    Science.gov (United States)

    Wang, Xuerui; Chi, Chenglong; Zhang, Kang; Qian, Yuhong; Gupta, Krishna M.; Kang, Zixi; Jiang, Jianwen; Zhao, Dan

    2017-02-01

    It is highly desirable to reduce the membrane thickness in order to maximize the throughput and break the trade-off limitation for membrane-based gas separation. Two-dimensional membranes composed of atomic-thick graphene or graphene oxide nanosheets have gas transport pathways that are at least three orders of magnitude higher than the membrane thickness, leading to reduced gas permeation flux and impaired separation throughput. Here we present nm-thick molecular sieving membranes composed of porous two-dimensional metal-organic nanosheets. These membranes possess pore openings parallel to gas concentration gradient allowing high gas permeation flux and high selectivity, which are proven by both experiment and molecular dynamics simulation. Furthermore, the gas transport pathways of these membranes exhibit a reversed thermo-switchable feature, which is attributed to the molecular flexibility of the building metal-organic nanosheets.

  16. A tunable and switchable single-longitudinal-mode dual-wavelength fiber laser with a simple linear cavity.

    Science.gov (United States)

    He, Xiaoying; Fang, Xia; Liao, Changrui; Wang, D N; Sun, Junqiang

    2009-11-23

    A simple linear cavity erbium-doped fiber laser based on a Fabry-Perot filter which consists of a pair of fiber Bragg gratings is proposed for tunable and switchable single-longitudinal-mode dual-wavelength operation. The single-longitudinal-mode is obtained by the saturable absorption of an unpumed erbium-doped fiber together with a narrow-band fiber Bragg grating. Under the high pump power (>166 mW) condition, the stable dual-wavelength oscillation with uniform amplitude can be realized by carefully adjusting the polarization controller in the cavity. Wavelength selection and switching are achieved by tuning the narrow-band fiber Bragg grating in the system. The spacing of the dual-wavelength can be selected at 0.20 nm (approximately 25.62 GHz), 0.22 nm (approximately 28.19 GHz) and 0.54 nm (approximately 69.19 GHz).

  17. Chitosan-Gated Magnetic-Responsive Nanocarrier for Dual-Modal Optical Imaging, Switchable Drug Release, and Synergistic Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hui [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Mu, Qingxin [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Revia, Richard [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Wang, Kui [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Zhou, Xuezhe [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Pauzauskie, Peter J. [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99354 USA; Zhou, Shuiqin [Department of Chemistry, The College of Staten Island, City University of New York, Staten Island NY 10314 USA; Zhang, Miqin [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA

    2017-01-25

    In this study, we present a multifunctional yet structurally simple nanocarrier that has a high drug loading capacity, releases drug in response to onset of an AC magnetic field, and can serve as a long-term imaging contrast agent and effectively kills cancer cells by synergistic action. This nanocarrier (HMMC-NC) has a spherical shell structure with a center cavity of 80 nm in diameter. The shell is comprised of two layers: an inner layer of magnetite that exhibits superparamagnetism and an outer layer of mesoporous carbon embedded with carbon dots that exhibit photoluminescence property. Thus in addition to being a drug carrier, HMMC-NC is also a contrast agent for bioimaging. The switchable drug release is enabled by the chitosan molecules attached on the nanocarrier as the switching material which turns on or off the drug release in response to the application or withdrawal of an AC magnetic field.

  18. Spectral study on conformation switchable cationic calix[4]carbazole serving as curcumin container, stabilizer and sustained-delivery carrier

    Science.gov (United States)

    Zhao, Liang; Kang, Le; Chen, Yan; Li, Gang; Wang, Lan; Hu, Chun; Yang, Peng

    2018-03-01

    A fluorescent 2,7-dimethoxy-substituted calix[4]carbazole (1) is facilely synthesized. The spectral behaviors of both the guest-induced switchable conformation of 1 and its abilities serving as the stabilizer and molecular carrier of curcumin are investigated. UV-vis, fluorescence and NMR spectral results show that upon binding to curcumin, the 1,3-alternate conformation of 1 is converted to be the cone one. The relative high association constant (6.4 × 106 M- 1) of 1 binding to curcumin enables it to stabilize the curcumin, to suppress its degradation, and to sustainably deliver it into the EYPC vesicles within 20 h. Moreover, the cytotoxicity assay shows that 1 does not interfere the antiproliferative activities of curcumin. All these properties endow 1 the potential capability of serving as the molecular drug carrier. Our current result may pave the way looking for more efficient fluorescent calixcarbazoles and thereof spectral utilities.

  19. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications.

    Science.gov (United States)

    Eom, Seung-Hyun; Seo, Yunsik; Lim, Sungjoon

    2015-12-10

    In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM) simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch.

  20. Produced Water Treatment Using the Switchable Polarity Solvent Forward Osmosis (SPS FO) Desalination Process: Preliminary Engineering Design Basis

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, Daniel; Adhikari, Birendra; Orme, Christopher; Wilson, Aaron

    2016-05-01

    Switchable Polarity Solvent Forward Osmosis (SPS FO) is a semi-permeable membrane-based water treatment technology. INL is currently advancing SPS FO technology such that a prototype unit can be designed and demonstrated for the purification of produced water from oil and gas production operations. The SPS FO prototype unit will used the thermal energy in the produced water as a source of process heat, thereby reducing the external process energy demands. Treatment of the produced water stream will reduce the volume of saline wastewater requiring disposal via injection, an activity that is correlated with undesirable seismic events, as well as generate a purified product water stream with potential beneficial uses. This paper summarizes experimental data that has been collected in support of the SPS FO scale-up effort, and describes how this data will be used in the sizing of SPS FO process equipment. An estimate of produced water treatment costs using the SPS FO process is also provided.

  1. Integrated power-heat-cold-coupling by switchable Stirling-Vuilleumier-Hybrid-Machines

    International Nuclear Information System (INIS)

    Kuehl, Hans-Detlev

    2017-01-01

    experimental effort, a similarity-theoretical scaling was carried out while keeping all dimensionless parameters relevant to the internal gas circulation process constant. Although the experimental results presented in this article therefore require a correction due to some external, not correctly scalable friction and insulation losses, they nevertheless prove that the realization of such switchable systems for decentralized, demand-oriented energy supply of buildings in a practical size and performance class is possible. In coordinated operation of a larger number of such systems - e.g. via ripple control or network load-dependent power consumption tariffs and power feed-in tariffs - can respond by appropriate switching between the operating conditions on load fluctuations in the public grid and so valuable, short-term retrievable control energy can be provided. Furthermore, applications in the field of drive-independent air conditioning, heating and power supply of vehicles are conceivable. [de

  2. Required Equipment for Photo-Switchable Donor-Acceptor (D-A) Dyad Interfacial Self-Assembled Monolayers for Organic Photovoltaic Cells

    Science.gov (United States)

    2014-01-24

    Accessory, 6) a Jelight Co. UVO cleaner, and 7) a Laurell Technologies Spin Coater . These instruments were used to characterize a variety of...goniometer/tensiometer, UVO cleaner, spin coater U U U UU Luis Echegoyen (915) 747-7573 (HBCU) - Required Equipment for Photo-switchable Donor...are exposed to the spin coated photoactive layer over the ITO monolayer, the effectiveness of this monolayer will be difficult to study. We need

  3. Polymeric microcapsules with switchable mechanical properties for self-healing concrete: synthesis, characterisation and proof of concept

    Science.gov (United States)

    Kanellopoulos, A.; Giannaros, P.; Palmer, D.; Kerr, A.; Al-Tabbaa, A.

    2017-04-01

    Microcapsules, with sodium silicate solution as core, were produced using complex coacervation in a double, oil-in-water-in oil, emulsion system. The shell material was a gelatin-acacia gum crosslinked coacervate and the produced microcapsules had diameters ranging from 300 to 700 μm. The shell material designed with switchable mechanical properties. When it is hydrated exhibits soft and ‘rubbery’ behaviour and, when dried, transitions to a stiff and ‘glassy’ material. The microcapsules survived drying and rehydrating cycles and preserved their structural integrity when exposed to highly alkaline solutions that mimic the pH environment of concrete. Microscopy revealed that the shell thickness of the microcapsules varies across their perimeter from 5 to 20 μm. Thermal analysis showed that the produced microcapsules were very stable up to 190 °C. Proof of concept investigation has demonstrated that the microcapsules successfully survive and function when exposed to a cement-based matrix. Observations showed that the microcapsules survive mixing with cement and rupture successfully upon crack formation releasing the encapsulated sodium silicate solution.

  4. Polypropylene Nonwoven Fabric@Poly(ionic liquid)s for Switchable Oil/Water Separation, Dye Absorption, and Antibacterial Applications.

    Science.gov (United States)

    Ren, Yongyuan; Guo, Jiangna; Lu, Qian; Xu, Dan; Qin, Jing; Yan, Feng

    2018-03-22

    Pollutants in wastewater include oils, dyes, and bacteria, making wastewater cleanup difficult. Multifunctional wastewater treatment media consisting of poly(ionic liquid)-grafted polypropylene (PP) nonwoven fabrics (PP@PIL) are prepared by a simple and scalable surface-grafting process. The fabricated PP@PIL fabrics exhibit impressive switchable oil/water separation (η>99 %) and dye absorption performance (q=410 mg g -1 ), as well as high antibacterial properties. The oil/water separation can be easily switched by anion exchanging of the PIL segments. Moreover, the multiple functions (oil/water separation, dye absorption, and antibacterial properties) occurred at the same time, and did not interfere with each other. The multifunctional fibrous filter can be easily regenerated by washing with an acid solution, and the absorption capacity is maintained after many recycling tests. These promising features make PIL-grafted PP nonwoven fabric a potential one-step treatment for multicomponent wastewater. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Coordinate-targeted and coordinate-stochastic super-resolution microscopy with the reversibly switchable fluorescent protein Dreiklang.

    Science.gov (United States)

    Jensen, Nickels A; Danzl, Johann G; Willig, Katrin I; Lavoie-Cardinal, Flavie; Brakemann, Tanja; Hell, Stefan W; Jakobs, Stefan

    2014-03-17

    Diffraction-unlimited far-field super-resolution fluorescence (nanoscopy) methods typically rely on transiently transferring fluorophores between two states, whereby this transfer is usually laid out as a switch. However, depending on whether this is induced in a spatially controlled manner using a pattern of light (coordinate-targeted) or stochastically on a single-molecule basis, specific requirements on the fluorophores are imposed. Therefore, the fluorophores are usually utilized just for one class of methods only. In this study we demonstrate that the reversibly switchable fluorescent protein Dreiklang enables live-cell recordings in both spatially controlled and stochastic modes. We show that the Dreiklang chromophore entails three different light-induced switching mechanisms, namely a reversible photochemical one, off-switching by stimulated emission, and a reversible transfer to a long-lived dark state from the S1 state, all of which can be utilized to overcome the diffraction barrier. We also find that for the single-molecule-based stochastic GSDIM approach (ground-state depletion followed by individual molecule return), Dreiklang provides a larger number of on-off localization events as compared to its progenitor Citrine. Altogether, Dreiklang is a versatile probe for essentially all popular forms of live-cell fluorescence nanoscopy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. A versatile light-switchable nanorod memory: Wurtzite ZnO on perovskite SrTiO3

    KAUST Repository

    Kumar, Anup Bera

    2013-04-25

    Integrating materials with distinct lattice symmetries and dimensions is an effective design strategy toward realizing novel devices with unprecedented functionalities, but many challenges remain in synthesis and device design. Here, a heterojunction memory made of wurtzite ZnO nanorods grown on perovskite Nb-doped SrTiO3 (NSTO) is reported, the electronic properties of which can be drastically reconfigured by applying a voltage and light. Despite of the distinct lattice structures of ZnO and NSTO, a consistent nature of single crystallinity is achieved in the heterojunctions via the low-temperature solution-based hydrothermal growth. In addition to a high and persistent photoconductivity, the ZnO/NSTO heterojunction diode can be turned into a versatile light-switchable resistive switching memory with highly tunable ON and OFF states. The reversible modification of the effective interfacial energy barrier in the concurrent electronic and ionic processes most likely gives rise to the high susceptibility of the ZnO/NSTO heterojunction to external electric and optical stimuli. Furthermore, this facile synthesis route is promising to be generalized to other novel functional nanodevices integrating materials with diverse structures and properties. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Isolation and characterization of a novel Rhodococcus strain with switchable carbonyl reductase and para-acetylphenol hydroxylase activities.

    Science.gov (United States)

    Zhang, Rui; Ren, Jie; Wang, Yu; Wu, Qiaqing; Wang, Min; Zhu, Dunming

    2013-01-01

    In the search for an effective biocatalyst for the reduction of acetophenones with unprotected hydroxy group on the benzene ring, a microorganism, which reduced para-acetylphenol to S-(-)-1-(para-hydroxyphenyl)ethanol under anaerobic conditions, was isolated from soil samples and the 16S rDNA study showed that it was phylogenetically affiliated with species of the genus Rhodococcus and was most similar to Rhodococcus pyridinivorans. Unexpectedly, this strain also hydroxylated para-acetylphenol to give 4-acetylcatechol in presence of oxygen, possessing para-acetylphenol hydroxylase activity. While the reduction of para-acetylphenol had an optimal reaction pH at 7 and a broad optimal temperature range (35-45 °C), the hydroxylation reached the maximum conversion at the pH range of 7-8 and 35 °C. This study identified for the first time a Rhodococcus strain with para-acetylphenol hydroxylase activity, which also contains highly enantioselective carbonyl reductase activity with potential applications for the asymmetric reduction of these less-explored but important ketones such as α-aminoacetophenone, 3'-hydroxyacetophenone and 4'-hydroxyacetophenone. The para-acetylphenol hydroxylase and carbonyl reductase activity are switchable by the reaction conditions.

  8. Synthesis of conformation switchable cationic polypeptides based on poly(S-propargyl-cysteine) for use as siRNA delivery.

    Science.gov (United States)

    Yi, Ling; Wang, Yisi; Lin, Guanliang; Lin, Danling; Chen, Wenliang; Huang, Yugang; Ye, Guodong

    2017-08-01

    Ring-opening polymerization of S-propargyl-cysteine-N-carboxyanhydride has been used to synthesize conformation switchable poly(S-propargyl-cysteine) starting with l-cysteine, dl- and d-cysteine. Then cationic polypeptides with different backbone chirality are obtained by nearly 100% side-chain grafting of cysteamine via thiol-yne click chemistry. The cationic polypeptides containing mixed conformations of β-sheets, β-turns and random coils are stable against pH, salt and temperature variations. The cationic polypeptides can condense siRNA at a low polypeptide/siRNA weight ratio to form nanoparticles with size depending on the backbone chirality. The cationic polypeptides derived from poly(S-propargyl-l or d-cysteine) are non-cytotoxic to HeLa and HepG2 cells, but interrupting the backbone chirality enhances the cytotoxicity sharply. The cationic polypeptides used for siRNA delivery show good transfection efficiency, but cell internalization process depends on the backbone chirality. The cationic polypeptide derived from the poly(S-propargyl-l-cysteine) is an appropriate siRNA vector with advantages of non-cytotoxicity and high transfection efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Smart multifunctional nanoagents for in situ monitoring of small molecules with a switchable affinity towards biomedical targets

    Science.gov (United States)

    Shevchenko, Konstantin G.; Cherkasov, Vladimir R.; Nikitina, Irina L.; Babenyshev, Andrey V.; Nikitin, Maxim P.

    2018-02-01

    The great diversity of nanomaterials provides ample opportunities for constructing effective agents for biomedical applications ranging from biosensing to drug delivery. Multifunctional nanoagents that combine several features in a single particle are of special interest due to capabilities that substantially exceed those of molecular drugs. An ideal theranostic agent should simultaneously be an advanced biosensor to identify a disease and report the diagnosis and a biomedical actuator to treat the disease. While many approaches were developed to load a nanoparticle with various drugs for actuation of the diseased cells (e.g., to kill them), the nanoparticle-based approaches for the localized biosensing with real-time reporting of the marker concentration severely lag behind. Here, we show a smart in situ nanoparticle-based biosensor/actuator system that dynamically and reversibly changes its structural and optical properties in response to a small molecule marker to allow real-time monitoring of the marker concentration and adjustment of the system ability to bind its biomedical target. Using the synergistic combination of signal readout based on the localized surface plasmon resonance and an original method of fabrication of smart ON/OFF-switchable nanoagents, we demonstrate reversible responsiveness of the system to a model small molecule marker (antibiotic chloramphenicol) in a wide concentration range. The proposed approach can be used for the development of advanced multifunctional nanoagents for theranostic applications.

  10. Characterization of Anthraquinone-DerivedRedox Switchable Ionophores and Their Complexes with Li+, Na+, K+, Ca+, and Mg+ Metal Ions

    Directory of Open Access Journals (Sweden)

    Vaishali Vyas

    2011-01-01

    Full Text Available Anthraquinone derived redox switchable ionophores 1,5 bis (2-(2-(2-ethoxy ethoxy ethoxyanthracene-9,10-dione (V1 and 1,8-bis(2-(2-(2-ethoxyethoxyethoxy anthracene—9,10-dione (V2 have been used for isolation, extraction and liquid membrane transport studies of Li+, Na+, K+, Ca2+ and Mg2+ metal ions. These isolated complexes were characterized by melting point determination, CV and IR, 1H NMR spectral analysis. Ionophore V2 shows maximum shift in reduction potential (ΔE with Ca(Pic2. The observed sequence for the shifting in reduction potential (ΔE between V2 and their complexes is V2 calcium picrate (42 mV > V2 potassium picrate (33 mV > V2 lithium picrate (25 mV > V2 sodium picrate (18 mV > V2 magnesium picrate (15 mV. These findings are also supported by results of extraction, back extraction and transport studies. Ionophore V2 complexed with KPic and showed much higher extractability and selectivity towards K+ than V1. These synthetic ionophores show positive and negative cooperativity towards alkali and alkaline earth metal ions in reduced and oxidized state. Hence, this property can be used in selective separation and enrichment of metal ions using electrochemically driven ion transport.

  11. Direct Imaging of Charge Density Modulation in Switchable Two-Dimensional Electron Gas at the Oxide Hetero-Interfaces by Using Electron Bean Inline Holography

    Science.gov (United States)

    2015-08-16

    Switchable Two-Dimensional Electron Gas at the Oxide Hetero-Interfaces by Using Electron Bean Inline Holography 5a. CONTRACT NUMBER FA2386-13-1-4136...directly imaged the charge carrier densities and spatial distributions at the (001) LaAlO3/SrTiO3 heterointerfaces by in-situ TEM holography . The new...Hetero-Interfaces by Using Electron Bean Inline Holography 5a. CONTRACT NUMBER FA2386-13-1-4136 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61102F

  12. Magnetoresponsive Poly(ether sulfone)-Based Iron Oxide cum Hydrogel Mixed Matrix Composite Membranes for Switchable Molecular Sieving.

    Science.gov (United States)

    Lin, Xi; Nguyen Quoc, Bao; Ulbricht, Mathias

    2016-10-26

    Stimuli-responsive membranes that can adjust mass transfer and interfacial properties "on demand" have drawn large interest over the last few decades. Here, we designed and prepared a novel magnetoresponsive separation membrane with remote switchable molecular sieving effect by simple one-step and scalable nonsolvent induced phase separation (NIPS) process. Specifically, poly(ether sulfone) (PES) as matrix for an anisotropic membrane, prefabricated poly(N-isopropylacrylamide) (PNIPAAm) nanogel (NG) particles as functional gates, and iron oxide magnetic nanoparticles (MNP) as localized heaters were combined in a synergistic way. Before membrane casting, the properties of the building blocks, including swelling property and size distribution for NG, and magnetic property and heating efficiency for MNP, were investigated. Further, to identify optimal film casting conditions for membrane preparation by NIPS, in-depth rheological study of the effects of composition and temperature on blend dope solutions was performed. At last, a composite membrane with 10% MNP and 10% NG blended in a porous PES matrix was obtained, which showed a large, reversible, and stable magneto-responsivity. It had 9 times higher water permeability at the "on" state of alternating magnetic field (AMF) than at the "off"-state. Moreover, the molecular weight cutoff of such membrane could be reversibly shifted from ∼70 to 1750 kDa by switching off or on the external AMF, as demonstrated in dextran ultrafiltration tests. Overall, it has been proved that the molecular sieving performance of the novel mixed matrix composite membrane can be controlled by the swollen/shrunken state of PNIPAAm NG embedded in the nanoporous barrier layer of a PES-based anisotropic porous matrix, via the heat generation of nearby MNP. And the structure of such membrane can be tailored by the NIPS process conditions. Such membrane has potential as enabling material for remote-controlled drug release systems or devices for

  13. Hexagonal boron nitride and graphene in-plane heterostructures: An experimentally feasible approach to charge-induced switchable CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Xin; Tahini, Hassan A.; Smith, Sean C., E-mail: sean.smith@unsw.edu.au

    2016-10-20

    Hexagonal boron nitride (h-BN) has been proposed as a sorbent material for charge-induced switchable CO{sub 2} capture. However, h-BN is a wide-gap semiconductor, hindering injection of the requisite charge. Here, we employ first-principle calculations to support the proposal that in-plane h-BN/graphene (P-BN/G) heterostructures, consisting of alternating strips of h-BN and graphene, may provide an experimentally feasible material platform for voltage-induced charging of h-BN strips to realize switchable CO{sub 2} capture. Our results show that a significant amount of injected negative charges are distributed onto h-BN strips of P-BN/G, such that CO{sub 2} capture/release can be simply controlled by switching on/off the charge states of P-BN/G system. At saturation CO{sub 2} capture coverage, the negatively charged P-BN/G heterostructures achieve CO{sub 2} capture capacities up to 2.27 × 10{sup 14} cm{sup −2}, which is twice that which can be achieved on stacked h-BN/graphene (S-BN/G) nanosheets.

  14. Tunable and switchable dual-wavelength single polarization narrow linewidth SLM erbium-doped fiber laser based on a PM-CMFBG filter.

    Science.gov (United States)

    Yin, Bin; Feng, Suchun; Liu, Zhibo; Bai, Yunlong; Jian, Shuisheng

    2014-09-22

    A tunable and switchable dual-wavelength single polarization narrow linewidth single-longitudinal-mode (SLM) erbium-doped fiber (EDF) ring laser based on polarization-maintaining chirped moiré fiber Bragg grating (PM-CMFBG) filter is proposed and demonstrated. For the first time as we know, the CMFBG inscribed on the PM fiber is applied for the wavelength-tunable and-switchable dual-wavelength laser. The PM-CMFBG filter with ultra-narrow transmission band (0.1 pm) and a uniform polarization-maintaining fiber Bragg grating (PM-FBG) are used to select the laser longitudinal mode. The stable single polarization SLM operation is guaranteed by the PM-CMFBG filter and polarization controller. A tuning range of about 0.25 nm with about 0.075 nm step is achieved by stretching the uniform PM-FBG. Meanwhile, the linewidth of the fiber laser for each wavelength is approximate 6.5 and 7.1 kHz with a 20 dB linewidth, which indicates the laser linewidth is approximate 325 Hz and 355 Hz FWHM.

  15. Switchable insulation for using solar energy in buildings. Final report; Schaltbare Waermedaemmung (SWD) zur Nutzung der Sonnenenergie in Gebaeuden. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stark, C.; Horn, R.; Hetfleisch, J.; Fricke, J.

    2003-02-25

    Solar energy can be used in buildings via use of transparent insulations. But thereby problems occur, like overheating of building walls in summer and heat losses in the cold season. To solve these problems ZAE Bayern has designed and optimized the switchable insulation SWD, the thermal conductivity of which can be changed from highly insulating to conducting. A computer routine was developed to calculate and to optimize the heat gains. The SWD is switched by desorbing/adsorbing as small amount of hydrogen gas. Desorption is facilitated with an electric heating element. The thermal conductivity of the filling can be varied by about a factor of 40. Several SWD-modules were produced and installed in an outside measuring facility. The heat gains and the durability were investigated for three years. The results of the simulation could be verified and ageing did not occur. For an optimal system the heat gains are in the range of 150 kWh/(m{sup 2}a). The mounting of these panels at south facades is simple, especially for post bolt systems. Contrary to transparent systems the loss of heat in winter is very small and the overheating of the walls behind the SWD in summer can be avoided. (orig.) [German] Zur Nutzung der Sonnenenergie in Gebaeuden werden bisher transparente Waermedaemmsysteme eingebaut, die jedoch oft mit Problemen wie Wandueberhitzung im Sommer und Waermeverlusten in der kalten Jahreszeit behaftet sind. Zur Loesung dieser Probleme wurde am ZAE Bayern eine schaltbare Waermedaemmung entwickelt und optimiert, deren Daemmeigenschaft je nach Sonneneinstrahlung und Waermebedarf variiert werden kann. Es wurde ein Programm entwickelt, mit dem die Waermegewinne berechnet und optimiert werden koennen. Die Schaltbarkeit wird durch einen Getter ermoeglicht, der eine ungefaehrliche Menge Wasserstoffgas reversibel aufnehmen und abgeben kann. Die Wasserstoff-Austreibung erfolgt mittels elektrischer Heizung und veraendert die Waermeleitfaehigkeit der Fuellung um einen

  16. Three-Way-Switchable (Right/Left/OFF) Selective Reflection of Circularly Polarized Light on Solid Thin Films of Helical Polymer Blends.

    Science.gov (United States)

    Nagata, Yuuya; Uno, Makoto; Suginome, Michinori

    2016-06-13

    Two poly(quinoxaline-2,3-diyl) copolymers bearing miscibility-enhancing 8-chlorooctyloxy and (S)-2-methylbutoxy or n-butoxy side chains were synthesized. After annealing in CHCl3 vapor, a polymer-blend film of these copolymers exhibited selective reflection of right-handed circularly polarized light (CPL) in the visible region. The handedness of the CPL reflected was completely inverted upon annealing of the film in THF vapor. Annealing in n-hexane vapor resulted in the phase separation of the polymer blend, which turned the selective reflection off. This three-way-switchable reflection, that is, reflection of right-handed or left-handed CPL, together with an OFF state, could be observed visually through right- and left-handed CPL filters. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Reversible conversion of valence-tautomeric copper metal-organic frameworks dependent single-crystal-to-single-crystal oxidation/reduction: a redox-switchable catalyst for C-H bonds activation reaction.

    Science.gov (United States)

    Huang, Chao; Wu, Jie; Song, Chuanjun; Ding, Ran; Qiao, Yan; Hou, Hongwei; Chang, Junbiao; Fan, Yaoting

    2015-06-28

    Upon single-crystal-to-single-crystal (SCSC) oxidation/reduction, reversible structural transformations take place between the anionic porous zeolite-like Cu(I) framework and a topologically equivalent neutral Cu(I)Cu(II) mixed-valent framework. The unique conversion behavior of the Cu(I) framework endowed it as a redox-switchable catalyst for the direct arylation of heterocycle C-H bonds.

  18. Relationship of light-output nonlinearities and light-output spikes in proton-bombarded stripe-geometry double-heterostructure (Al,Ga)As lasers

    International Nuclear Information System (INIS)

    Dixon, R.W.; Joyce, W.B.; Miller, R.C.

    1979-01-01

    By using a fast photodetector and a simple spatial filtering technique, the relationship between the optical spike which frequently appears at the leading edge of a pulsed-GaAs-laser response and the optical nonlinearities called kinks has been investigated. It is suggested that the spike can be viewed consistently as a transition period during which the lasing mode distortion, which has been previously associated with kinks, occurs. It is the time taken for the kink to become established. During the spike, light emisson occurs with a spatial and angular intensity distribution consistent with the lasing which would be appropriate if the kink did not exist. It is shown that the experimental technique can also be used to investigate sustained laser optical-intensity oscillations

  19. An effervescence-assisted switchable fatty acid-based microextraction with solidification of floating organic droplet for determination of fluoroquinolones and tetracyclines in seawater, sediment, and seafood.

    Science.gov (United States)

    Gao, Ming; Wang, Jun; Song, Xiukai; He, Xin; Dahlgren, Randy A; Zhang, Zhenzhong; Ru, Shaoguo; Wang, Xuedong

    2018-04-01

    This study developed a new effervescence-assisted switchable fatty acid-based microextraction combined with solidification of a floating organic-droplet (EA-SFAM-SFO) for simple and rapid determination of fluoroquinolones and tetracyclines in seawater, sediment, and seafood. Five medium-chain fatty acids (pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, and nonanoic acid) were tested as an extraction solvent, given their ability to change between hydrophobic and hydrophilic forms by pH adjustment. As nonanoic acid had the highest extraction recovery (>92%) for the six antibiotics and the ability to transform from liquid to a solidified floating state at low temperature, it was selected as the optimum extraction solvent. The prominent advantages of the newly developed method are: (1) reaction between the procedures salt and fatty acid changed extraction solvent from the hydrophobic to hydrophilic state; (2) bubbling with CO 2 greatly increased the contact area between fatty acid and analytes resulting in improved extraction recovery; and (3) solidification of the fatty acid at a low temperature provided good separation and avoided the use of specialized equipment. Single-factor screening and optimization of the main factors were conducted using Plackett-Burman design and central composite design, respectively. The main parameters were optimized as follows: 258 μL fatty acid, 406 μL H 2 SO 4 (98%), 3.9 min vortex time, and 354 μL Na 2 CO 3 (2 mol L - 1). Under optimized conditions, limits of detection were 0.007-0.113 μg L -1 or μg kg -1 and extraction recoveries were 82.2%-116.7% for six fluoroquinolone and tetracycline antibiotics in seawater, sediments, and seafood. The newly developed method combines the advantages of effervescence-assisted dispersion, hydrophobic/hydrophilic switchable solvent, and liquid/solid transition induced by low temperature. Overall, the new method is simple, quick, and environment-friendly with low detection limits and

  20. Self-assembly of block copolymers into sieve-like particles with arrayed switchable channels and as scaffolds to guide the arrangement of gold nanoparticles.

    Science.gov (United States)

    He, Yun; Zhang, Yan; Yan, Nan; Zhu, Yutian; Jiang, Wei; Shi, Dean

    2017-10-12

    Well-defined polymeric particles with not only a controllable shape and internal nanostructures but also stimuli-responsive functions have attracted intensive attention because of their great potential in various fields. Herein, we created unique sieve-like particles with lattice arrayed switchable channels via the confined self-assembly of poly(4-vinylpyridine)-b-polystyrene-b-poly(4-vinylpyridine) (P4VP-b-PS-b-P4VP) triblock copolymers within the emulsion droplets and the subsequent swelling treatment in ethanol. It is worth noting that the hexagonally packed P4VP channels in the sieve-like particles are switched on and off by changing the solvent type, i.e., P4VP channels are switched on in ethanol and switched off in water, which can operate as a solvent-controlled chemical gate. Moreover, the well-defined sieve-like particles can be further used as scaffolds to guide the spatial arrangement of gold nanoparticles, which generates hybrid nanomaterials with controllable morphology and ordered spatial arrangement of AuNPs.

  1. 1.8 Å bright-state structure of the reversibly switchable fluorescent protein Dronpa guides the generation of fast switching variants

    Science.gov (United States)

    Stiel, Andre C.; Trowitzsch, Simon; Weber, Gert; Andresen, Martin; Eggeling, Christian; Hell, Stefan W.; Jakobs, Stefan; Wahl, Markus C.

    2006-01-01

    RSFPs (reversibly switchable fluorescent proteins) may be repeatedly converted between a fluorescent and a non-fluorescent state by irradiation and have attracted widespread interest for many new applications. The RSFP Dronpa may be switched with blue light from a fluorescent state into a non-fluorescent state, and back again with UV light. To obtain insight into the underlying molecular mechanism of this switching, we have determined the crystal structure of the fluorescent equilibrium state of Dronpa. Its bicyclic chromophore is formed spontaneously from the Cys62–Tyr63–Gly64 tripeptide. In the fluorescent state, it adopts a slightly non-coplanar cis conformation within the interior of a typical GFP (green fluorescent protein) β-can fold. Dronpa shares some structural features with asFP595, another RSFP whose chromophore has previously been demonstrated to undergo a cis–trans isomerization upon photoswitching. Based on the structural comparison with asFP595, we have generated new Dronpa variants with an up to more than 1000-fold accelerated switching behaviour. The mutations which were introduced at position Val157 or Met159 apparently reduce the steric hindrance for a cis–trans isomerization of the chromophore, thus lowering the energy barrier for the blue light-driven on-to-off transition. The findings reported in the present study support the view that a cis–trans isomerization is one of the key events common to the switching mechanism in RSFPs. PMID:17117927

  2. 1.8 A bright-state structure of the reversibly switchable fluorescent protein Dronpa guides the generation of fast switching variants.

    Science.gov (United States)

    Stiel, Andre C; Trowitzsch, Simon; Weber, Gert; Andresen, Martin; Eggeling, Christian; Hell, Stefan W; Jakobs, Stefan; Wahl, Markus C

    2007-02-15

    RSFPs (reversibly switchable fluorescent proteins) may be repeatedly converted between a fluorescent and a non-fluorescent state by irradiation and have attracted widespread interest for many new applications. The RSFP Dronpa may be switched with blue light from a fluorescent state into a non-fluorescent state, and back again with UV light. To obtain insight into the underlying molecular mechanism of this switching, we have determined the crystal structure of the fluorescent equilibrium state of Dronpa. Its bicyclic chromophore is formed spontaneously from the Cys62-Tyr63-Gly64 tripeptide. In the fluorescent state, it adopts a slightly non-coplanar cis conformation within the interior of a typical GFP (green fluorescent protein) b-can fold. Dronpa shares some structural features with asFP595, another RSFP whose chromophore has previously been demonstrated to undergo a cis-trans isomerization upon photoswitching. Based on the structural comparison with asFP595, we have generated new Dronpa variants with an up to more than 1000-fold accelerated switching behaviour. The mutations which were introduced at position Val157 or Met159 apparently reduce the steric hindrance for a cis-trans isomerization of the chromophore, thus lowering the energy barrier for the blue light-driven on-to-off transition. The findings reported in the present study support the view that a cis-trans isomerization is one of the key events common to the switching mechanism in RSFPs.

  3. Wavelength-switchable multiwavelength erbium-doped fiber laser based on a D-shaped fiber with a photoresist thin-film overlay

    Energy Technology Data Exchange (ETDEWEB)

    Han, Young-Geun [Hanyang University, Seoul (Korea, Republic of)

    2011-04-15

    A wavelength-switchable multiwavelength erbium-doped fiber (EDF) laser based on a D-shaped fiber with a photoresist (PR) thin-film overlay is proposed and experimentally demonstrated. The D-shaped fiber with a PR thin-film overlay is implemented as a multichannel filter. Based on the evanescent field coupling between the D-shaped fiber and the PR thin-film overlay, periodic transmission characteristics are obtained. The wavelength spacing of the D-shaped fiber with the PR thin-film overlay is controlled by changing the thickness and the refractive index of the PR thin film overlay. By inserting the proposed multichannel filter into an EDF ring laser, a multiwavelength EDF laser is achieved. The homogenous line broadening of erbium ions for the realization of stable operation of the multiwavelength EDF ring laser is suppressed by using a nonlinear polarization rotation. A high-quality multiwavelength output with a high extinction ratio of {approx}0 dB is realized. The output fluctuation of the proposed multiwavelength EDF ring laser is measured to be less than 0.3 dB. Since the transmission characteristics of the proposed multichannel filter are controlled by using two orthogonal input polarization states, multiwavelength lasing outputs are switched.

  4. "On-off" switchable tool for food sample preparation: merging molecularly imprinting technology with stimuli-responsive blocks. Current status, challenges and highlighted applications.

    Science.gov (United States)

    Garcia, Raquel; Gomes da Silva, Marco D R; Cabrita, Maria João

    2018-01-01

    Sample preparation still remains a great challenge in the analytical workflow representing the most time-consuming and laborious step in analytical procedures. Ideally, sample pre-treatment procedures must be more selective, cheap, quick and environmental friendly. Molecular imprinting technology is a powerful tool in the development of highly selective sample preparation methodologies enabling to preconcentrate the analytes from a complex food matrix. Actually, the design and development of molecularly imprinted polymers-based functional materials that merge an enhancement of selectivity with a controllable and switchable mode of action by means of specific stimulus constitutes a hot research topic in the field of food analysis. Thus, combining the stimuli responsive mechanism and imprinting technology a new generation of materials are emerging. The application of these smart materials in sample preparation is in early stage of development, nevertheless new improvements will promote a new driven in the demanding field of food sample preparation. The new trends in the advancement of food sample preparation using these smart materials will be presented in this review and highlighted the most relevant applications in this particular area of knowledge. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Switchable dual-wavelength single-longitudinal-mode erbium-doped fiber laser using an inverse-Gaussian apodized fiber Bragg grating filter and a low-gain semiconductor optical amplifier.

    Science.gov (United States)

    Lin, Bo; Tjin, Swee Chuan; Zhang, Han; Tang, Dingyuan; Hao, Jianzhong; Dong, Bo; Liang, Sheng

    2010-12-20

    We present a stable and switchable dual-wavelength erbium-doped fiber laser. In the ring cavity, an inverse-Gaussian apodized fiber Bragg grating serves as an ultranarrow dual-wavelength passband filter, a semiconductor optical amplifier biased in the low-gain regime reduces the gain competition of the two wavelengths, and a feedback fiber loop acts as a mode filter to guarantee a stable single-longitudinal-mode operation. Two lasing lines with a wavelength separation of approximately 0.1 nm are obtained experimentally. A microwave signal at 12.51 GHz is demonstrated by beating the dual wavelengths at a photodetector.

  6. Performance analysis of photoresistor and phototransistor for automotive’s halogen and xenon bulbs light output

    Science.gov (United States)

    Rammohan, A.; Kumar, C. Ramesh

    2017-11-01

    Illumination of any light is measured using a different kind of calibrated equipment’s available in the market such as a goniometer, spectral radiometer, photometer, Lux meter and camera based systems which directly display the illumination of automotive headlights light distribution in the unit of lux, foot-candles, lumens/sq. ft. and Lambert etc., In this research, we dealt with evaluating the photo resistor or Light Dependent Resistor (LDR) and phototransistor whether it is useful for sensing light patterns of Automotive Halogen and Xenon bulbs. The experiments are conducted during night hours under complete dark space. We have used the headlamp setup available in TATA SUMO VICTA vehicle in the Indian market and conducted the experiments separately for Halogen and Xenon bulbs under low and high beam operations at various degrees and test points within ten meters of distance. Also, we have compared the light intensity of halogen and xenon bulbs to prove the highest light intensity between halogen and Xenon bulbs. After doing a rigorous test with these two sensors it is understood both are good to sensing beam pattern of automotive bulbs and even it is good if we use an array of sensors or a mixed combination of sensors for measuring illumination purposes under perfect calibrations.

  7. Birks' scaling of the particle light output functions for the EJ 299-33 plastic scintillator

    Science.gov (United States)

    Nyibule, S.; Tõke, J.; Henry, E.; Schröder, W. U.; Acosta, L.; Auditore, L.; Cardella, G.; De Filippo, E.; Francalanza, L.; Gianì, S.; Minniti, T.; Morgana, E.; Pagano, E. V.; Pirrone, S.; Politi, G.; Quattrocchi, L.; Russotto, P.; Trifirò, A.; Trimarchi, M.

    2014-12-01

    The response of the EJ 299-33 plastic scintillator to energetic charged nuclear particles ranging from isotopes of hydrogen to carbon-12 has been analyzed in terms of Birks' semi-empirical approach over the wide range of particle energies from 2 to 20 AMeV. It was found that while the original two-parameter scaling involving Birks' composite quenching parameter kB and an overall conversion efficiency parameter S may be applicable to select sets of particles, a more universal fit would still require individual scintillation efficiencies Sx for individual particle species and more than just one value of the composite Birks' constant kB.

  8. Photonic crystals: A novel approach to enhance the light output of scintillation based detectors

    CERN Document Server

    Knapitsch, A; Leclercq, J L; Letartre, X; Auffray, E; Fabjan, C W

    2011-01-01

    Future high-energy physics (HEP) experiments as well as next generation medical imaging applications are more and more pushing towards better scintillation characteristics. One of the problems in heavy scintillating materials is related to their high electronic density, resulting in a large index of refraction. As a consequence, most of the scintillation light produced in the bulk material is trapped inside the crystal due to total internal reflection. The same problem also occurs with light emitting diodes (LEDs) and has for a long time been considered as a limiting factor for their overall efficiency. Recent studies have shown that those limits can be overcome by means of light scattering effects of photonic crystals (PhCs). In our simulations we could show light yield improvements between 90\\% and 110\\% when applying PhC structures to different scintillator materials. To evaluate the results, a PhC modified scintillator was produced in cooperation with the NIL (Nanotechnology Institute of Lyon). By using s...

  9. Morning and Evening Oscillators Cooperate to Reset Circadian Behavior in Response to Light Input

    Directory of Open Access Journals (Sweden)

    Pallavi Lamba

    2014-05-01

    Full Text Available Light is a crucial input for circadian clocks. In Drosophila, short light exposure can robustly shift the phase of circadian behavior. The model for this resetting posits that circadian photoreception is cell autonomous: CRYPTOCHROME senses light, binds to TIMELESS (TIM, and promotes its degradation, which is mediated by JETLAG (JET. However, it was recently proposed that interactions between circadian neurons are also required for phase resetting. We identify two groups of neurons critical for circadian photoreception: the morning (M and the evening (E oscillators. These neurons work synergistically to reset rhythmic behavior. JET promotes acute TIM degradation cell autonomously in M and E oscillators but also nonautonomously in E oscillators when expressed in M oscillators. Thus, upon light exposure, the M oscillators communicate with the E oscillators. Because the M oscillators drive circadian behavior, they must also receive inputs from the E oscillators. Hence, although photic TIM degradation is largely cell autonomous, neural cooperation between M and E oscillators is critical for circadian behavioral photoresponses.

  10. Method and apparatus for wavefront sensing

    Energy Technology Data Exchange (ETDEWEB)

    Bahk, Seung-Whan

    2018-03-20

    A method for performing optical wavefront sensing includes providing an amplitude transmission mask having a light input side, a light output side, and an optical transmission axis passing from the light input side to the light output side. The amplitude transmission mask is characterized by a checkerboard pattern having a square unit cell of size .LAMBDA.. The method also includes directing an incident light field having a wavelength $ \\lamda $ to be incident on the light input side and propagating the incident light field through the amplitude transmission mask. The method further includes producing a plurality of diffracted light fields on the light output side and detecting, at a detector disposed a distance L from the amplitude transmission mask, an interferogram associated with the plurality of diffracted light fields.

  11. Observation of Switchable Photoresponse of a Monolayer WSe 2 –MoS 2 Lateral Heterostructure via Photocurrent Spectral Atomic Force Microscopic Imaging

    KAUST Repository

    Son, Youngwoo

    2016-04-27

    In the pursuit of two-dimensional (2D) materials beyond graphene, enormous advances have been made in exploring the exciting and useful properties of transition metal dichalcogenides (TMDCs), such as a permanent band gap in the visible range and the transition from indirect to direct band gap due to 2D quantum confinement, and their potential for a wide range of device applications. In particular, recent success in the synthesis of seamless monolayer lateral heterostructures of different TMDCs via chemical vapor deposition methods has provided an effective solution to producing an in-plane p-n junction, which is a critical component in electronic and optoelectronic device applications. However, spatial variation of the electronic and optoelectonic properties of the synthesized heterojunction crystals throughout the homogeneous as well as the lateral junction region and the charge carrier transport behavior at their nanoscale junctions with metals remain unaddressed. In this work, we use photocurrent spectral atomic force microscopy to image the current and photocurrent generated between a biased PtIr tip and a monolayer WSe2-MoS2 lateral heterostructure. Current measurements in the dark in both forward and reverse bias reveal an opposite characteristic diode behavior for WSe2 and MoS2, owing to the formation of a Schottky barrier of dissimilar properties. Notably, by changing the polarity and magnitude of the tip voltage applied, pixels that show the photoresponse of the heterostructure are observed to be selectively switched on and off, allowing for the realization of a hyper-resolution array of the switchable photodiode pixels. This experimental approach has significant implications toward the development of novel optoelectronic technologies for regioselective photodetection and imaging at nanoscale resolutions. Comparative 2D Fourier analysis of physical height and current images shows high spatial frequency variations in substrate/MoS2 (or WSe2) contact that

  12. Switchable Materials for Smart Windows.

    Science.gov (United States)

    Wang, Yang; Runnerstrom, Evan L; Milliron, Delia J

    2016-06-07

    This article reviews the basic principles of and recent developments in electrochromic, photochromic, and thermochromic materials for applications in smart windows. Compared with current static windows, smart windows can dynamically modulate the transmittance of solar irradiation based on weather conditions and personal preferences, thus simultaneously improving building energy efficiency and indoor human comfort. Although some smart windows are commercially available, their widespread implementation has not yet been realized. Recent advances in nanostructured materials provide new opportunities for next-generation smart window technology owing to their unique structure-property relations. Nanomaterials can provide enhanced coloration efficiency, faster switching kinetics, and longer lifetime. In addition, their compatibility with solution processing enables low-cost and high-throughput fabrication. This review also discusses the importance of dual-band modulation of visible and near-infrared (NIR) light, as nearly 50% of solar energy lies in the NIR region. Some latest results show that solution-processable nanostructured systems can selectively modulate the NIR light without affecting the visible transmittance, thus reducing energy consumption by air conditioning, heating, and artificial lighting.

  13. Birks' scaling of the particle light output functions for the EJ 299-33 plastic scintillator

    International Nuclear Information System (INIS)

    Nyibule, S.; Tõke, J.; Henry, E.; Schröder, W.U.; Acosta, L.; Auditore, L.; Cardella, G.; De Filippo, E.; Francalanza, L.; Gianì, S.; Minniti, T.; Morgana, E.; Pagano, E.V.; Pirrone, S.; Politi, G.; Quattrocchi, L.; Russotto, P.

    2014-01-01

    The response of the EJ 299-33 plastic scintillator to energetic charged nuclear particles ranging from isotopes of hydrogen to carbon-12 has been analyzed in terms of Birks' semi-empirical approach over the wide range of particle energies from 2 to 20 AMeV. It was found that while the original two-parameter scaling involving Birks' composite quenching parameter kB and an overall conversion efficiency parameter S may be applicable to select sets of particles, a more universal fit would still require individual scintillation efficiencies S x for individual particle species and more than just one value of the composite Birks' constant kB

  14. Birks' scaling of the particle light output functions for the EJ 299-33 plastic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Nyibule, S. [University of Rochester, Department of Physics, Rochester, NY 14627 (United States); Tõke, J.; Henry, E. [University of Rochester, Department of Chemistry, Rochester, NY 14627 (United States); Schröder, W.U., E-mail: w.udo.schroeder@rochester.edu [University of Rochester, Department of Physics, Rochester, NY 14627 (United States); University of Rochester, Department of Chemistry, Rochester, NY 14627 (United States); Acosta, L. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania (Italy); Departamento de Fisica Aplicada, Universidad de Huelva, Huelva (Spain); Auditore, L. [Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Messina and Department of Physics, Messina University, Messina (Italy); Cardella, G.; De Filippo, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Catania (Italy); Francalanza, L. [Department of Physics and Astronomy, Catania University, Catania (Italy); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania (Italy); Gianì, S. [Department of Physics and Astronomy, Catania University, Catania (Italy); Minniti, T.; Morgana, E. [Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Messina and Department of Physics, Messina University, Messina (Italy); Pagano, E.V. [Department of Physics and Astronomy, Catania University, Catania (Italy); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania (Italy); Pirrone, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Catania (Italy); Politi, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Catania (Italy); Department of Physics and Astronomy, Catania University, Catania (Italy); Quattrocchi, L. [Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Messina and Department of Physics, Messina University, Messina (Italy); Russotto, P. [Istituto Nazionale di Fisica Nucleare, Sezione di Catania (Italy); and others

    2014-12-21

    The response of the EJ 299-33 plastic scintillator to energetic charged nuclear particles ranging from isotopes of hydrogen to carbon-12 has been analyzed in terms of Birks' semi-empirical approach over the wide range of particle energies from 2 to 20 AMeV. It was found that while the original two-parameter scaling involving Birks' composite quenching parameter kB and an overall conversion efficiency parameter S may be applicable to select sets of particles, a more universal fit would still require individual scintillation efficiencies S{sub x} for individual particle species and more than just one value of the composite Birks' constant kB.

  15. QUASIMODO, a novel GPI-anchored zona pellucida protein involved in light input to the Drosophila circadian clock

    Czech Academy of Sciences Publication Activity Database

    Chen, K. F.; Peschel, N.; Závodská, Radka; Sehadová, Hana; Stanewsky, R.

    2011-01-01

    Roč. 21, č. 9 (2011), s. 719-729 ISSN 0960-9822 R&D Projects: GA MŠk LC07032 Institutional research plan: CEZ:AV0Z50070508 Keywords : QUASIMODO * Drosophila * circadian clock Subject RIV: ED - Physiology Impact factor: 9.647, year: 2011

  16. Switchable Polarization in Mn Embedded Graphene.

    Science.gov (United States)

    Noor-A-Alam, Mohammad; Ullah, Hamid; Shin, Young-Han

    2018-03-14

    Graphene, despite its many unique properties, is neither intrinsically polar due to inversion symmetry nor magnetic. However, based on density functional theory, we find that Mn, one of transition metals, embedded in single or double vacancy (Mn@SV and Mn@DV) in a graphene monolayer induces a dipole moment perpendicular to the sheet, which can be switched from up to down by Mn penetration through the graphene. Such switching could be realized by an external stimuli introduced through the tip of a scanning probe microscope, as already utilized in the studies of molecular switches. We estimate the energy barriers for dipole switching, which are found to be 2.60 eV and 0.28 eV for Mn@SV and Mn@DV, respectively. However, by applying biaxial tensile strain, we propose a mechanism for tuning the barrier. We find that 10% biaxial tensile strain, which is already experimentally achievable in graphene-like two-dimensional materials, can significantly reduce the barrier to 0.16 eV in Mn@SV. Moreover, in agreement with previous studies, we find a high magnetic moment of 3 μ B for both Mn@SV and Mn@DV, promising the potential of these structures in spintronics as well as in nanoscale electro-mechanical or memory devices.

  17. Switchable adhesion by chemical functionality and topography

    NARCIS (Netherlands)

    Kamperman, M.M.G.; Synytska, A.

    2012-01-01

    Progress in adhesion technology over the last few decades has led to widespread replacement of mechanical fasteners with adhesive bonds. Despite the advances, it remains challenging to produce materials that are sticky on demand. In this feature article we highlight recent efforts to develop

  18. Switchable solvents and methods of use thereof

    Science.gov (United States)

    Jessop, Philip G [Kingston, CA; Eckert, Charles A [Atlanta, GA; Liotta, Charles L [Atlanta, GA; Heldebrant, David J [Richland, WA

    2011-07-19

    A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

  19. Shape-Memory PVDF Exhibiting Switchable Piezoelectricity.

    Science.gov (United States)

    Hoeher, Robin; Raidt, Thomas; Novak, Nikola; Katzenberg, Frank; Tiller, Joerg C

    2015-12-01

    In this study, a material is designed which combines the properties of shape-memory and electroactive polymers. This is achieved by covalent cross-linking of polyvinylidene fluoride. The resulting polymer network exhibits excellent shape-memory properties with a storable strain of 200%, and fixity as well as recovery values of 100%. Programming upon rolling induces the transformation from the nonelectroactive α-phase to the piezoelectric β-phase. The highest β-phase content is found to be 83% for a programming strain of 200% affording a d33 value of -30 pm V(-1). This is in good accordance with literature known values for piezoelectric properties. Thermal triggering this material does not only result in a shape change but also renders the material nonelectroactive. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Electrically switchable chromogenic materials for external glazing

    Energy Technology Data Exchange (ETDEWEB)

    Cupelli, Daniela; Nicoletta, Fiore Pasquale [Dipartimento di Scienze Farmaceutiche, Universita della Calabria, 87036 Rende (CS) (Italy); Manfredi, Sabrina; Filpo, Giovanni De; Chidichimo, Giuseppe [Dipartimento di Chimica, Universita della Calabria, 87036 Rende (CS) (Italy)

    2009-03-15

    The development of chromogenic materials is important for their potential applications as electrically adjustable or thermally self-adjusting light and heat filters in the external glazing of buildings. Recently, we have reported our investigations on electrolyte-liquid crystal dispersions, which show independent electro-optical and electrochromic properties characterized by fast bleaching times. Nevertheless, for the external glazing of buildings, it is recommended to have a transparent off state, which turns opaque upon application of the external field. In this paper, we present our efforts to homeotropically align by rough surfaces fluid mixtures of a low molecular mass liquid crystal with a negative dielectric anisotropy, a liquid crystalline monomer, and electrolyte molecules in order to obtain transparent films after a polymerization process. Upon application of an ac electric field, the device becomes opaque and if a dc field is added, the cell changes colour too. We have also investigated the relationship between electro-optical/chromogenic response and physical chemical properties of the components. (author)

  1. Development of Switchable Polarity Solvent Draw Solutes

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Aaron D.

    2016-11-01

    Results of a computational fluid dynamic (CFD) study of flow and heat transfer in a printed circuit heat exchanger (PCHE) geometry are presented. CFD results obtained from a two-plate model are compared to corresponding experimental results for the validation. This process provides the basis for further application of the CFD code to PCHE design and performance analysis in a variety of internal flow geometries. As a part of the code verification and validation (V&V) process, CFD simulation of a single semicircular straight channel under laminar isothermal conditions was also performed and compared to theoretical results. This comparison yielded excellent agreement with the theoretical values. The two-plate CFD model based on the experimental PCHE design overestimated the effectiveness and underestimated the pressure drop. However, it is found that the discrepancy between the CFD result and experimental data was mainly caused by the uncertainty in the geometry of heat exchanger during the fabrication. The CFD results obtained using a slightly smaller channel diameter yielded good agreement with the experimental data. A separate investigation revealed that the average channel diameter of the OSU PCHE after the diffusion-bonding was 1.93 mm on the cold fluid side and 1.90 mm on the hot fluid side which are both smaller than the nominal design value. Consequently, the CFD code was shown to have sufficient capability to evaluate the heat exchanger thermal-hydraulic performance.

  2. Switchable Shape Memory Alloys (SMA) Thermal Materials

    Data.gov (United States)

    National Aeronautics and Space Administration — Materials and systems are being designed and developed to meet complex operational requirements while being kept lightweight, efficient, and robust. Multifunctional...

  3. Improvement in light-output efficiency of near-ultraviolet InGaN-GaN LEDs fabricated on stripe patterned sapphire substrates

    International Nuclear Information System (INIS)

    Lee, Y.J.; Hsu, T.C.; Kuo, H.C.; Wang, S.C.; Yang, Y.L.; Yen, S.N.; Chu, Y.T.; Shen, Y.J.; Hsieh, M.H.; Jou, M.J.; Lee, B.J.

    2005-01-01

    InGaN/GaN multi-quantum wells near ultraviolet light-emitting diodes (LEDs) were fabricated on a patterned sapphire substrate (PSS) with parallel stripe along the sapphire direction by using low-pressure metal-organic chemical vapor deposition (MOCVD). The forward- and reverse-bias electrical characteristics of the stripe PSS LEDs are, respectively, similar and better than those of conventional LEDs on sapphire substrate. The output power of the epoxy package of stripe PSS LED was 20% higher than that of the conventional LEDs. The enhancement of output power is due not only to the reduction of dislocation density but also to the release of the guided light in LEDs by the geometric shape of the stripe PSS, according to the ray-tracing analysis

  4. Effects of a chronic reduction of short-wavelength light input on melatonin and sleep patterns in humans: evidence for adaptation.

    Science.gov (United States)

    Giménez, Marina C; Beersma, Domien G M; Bollen, Pauline; van der Linden, Matthijs L; Gordijn, Marijke C M

    2014-06-01

    Light is an important environmental stimulus for the entrainment of the circadian clock and for increasing alertness. The intrinsically photosensitive ganglion cells in the retina play an important role in transferring this light information to the circadian system and they are elicited in particular by short-wavelength light. Exposure to short wavelengths is reduced, for instance, in elderly people due to yellowing of the ocular lenses. This reduction may be involved in the disrupted circadian rhythms observed in aged subjects. Here, we tested the effects of reduced blue light exposure in young healthy subjects (n = 15) by using soft orange contact lenses (SOCL). We showed (as expected) that a reduction in the melatonin suppressing effect of light is observed when subjects wear the SOCL. However, after chronic exposure to reduced (short wavelength) light for two consecutive weeks we observed an increase in sensitivity of the melatonin suppression response. The response normalized as if it took place under a polychromatic light pulse. No differences were found in the dim light melatonin onset or in the amplitude of the melatonin rhythms after chronic reduced blue light exposure. The effects on sleep parameters were limited. Our results demonstrate that the non-visual light system of healthy young subjects is capable of adapting to changes in the spectral composition of environmental light exposure. The present results emphasize the importance of considering not only the short-term effects of changes in environmental light characteristics.

  5. Threshold-Switchable Particles (TSP) to Control Internal Hemorrhage

    Science.gov (United States)

    2012-12-01

    Four different ratios of P700:SNP were tested – 0.2, 0.4, 0.6, and 1. Similarly to P70, preliminary 19 Figure 25 - (A) Blue coumarin dye...experiment at time 0 min. (B) Blue coumarin experiment at time 20 min. clotting assays suggest that clot time decreases with a ratio of P700:SNP above...we also tested the coagulation threshold response using a thrombin- specific blue coumarin dye. Our experiments use the method established by the

  6. Threshold-Switchable Particles (TSP) to Control Internal Hemorrhage

    Science.gov (United States)

    2013-12-01

    accelerate clotting. During Q2, we’ve tested the P70 functionalization on hydroxyapatite . While more complicated than silica, we were able to...unbranched polymer composed of orthophosphate monomers. Extremely conserved and ubiquitous across a diverse range of organisms, its physiological function ...with some success, but the goal of functionally delivering a procoagulant therapy to treat internal hemorrhage in practice has yet to be fully realized

  7. Switchable static friction of piezoelectric composite-silicon wafer contacts

    NARCIS (Netherlands)

    Ende, D.A. van den; Fischer, H.R.; Groen, W.A.; Zwaag, S. van der

    2013-01-01

    The meso-scale surface roughness of piezoelectric fiber composites can be manipulated by applying an electric field to a piezocomposite with a polished surface. In the absence of an applied voltage, the tips of the embedded piezoelectric ceramic fibers are below the surface of the piezocomposite and

  8. Switchable polarization rotation of visible light using a plasmonic metasurface

    Directory of Open Access Journals (Sweden)

    Stuart K. Earl

    2017-01-01

    Full Text Available A metasurface comprising an array of silver nanorods supported by a thin film of the phase change material vanadium dioxide is used to rotate the primary polarization axis of visible light at a pre-determined wavelength. The dimensions of the rods were selected such that, across the two phases of vanadium dioxide, the two lateral localized plasmon resonances (in the plane of the metasurface occur at the same wavelength. Illumination with linearly polarized light at 45° to the principal axes of the rod metasurface enables excitation of both of these resonances. Modulating the phase of the underlying substrate, we show that it is possible to reversibly switch which axis of the metasurface is resonant at the operating wavelength. Analysis of the resulting Stokes parameters indicates that the orientation of the principal linear polarization axis of the reflected signal is rotated by 90° around these wavelengths. Dynamic metasurfaces such as these have the potential to form the basis of an ultra-compact, low-energy multiplexer or router for an optical signal.

  9. A CO2-switchable amidine monomer: synthesis and characterization.

    Science.gov (United States)

    Liu, Hanbin; Yin, Hongyao; Feng, Yujun

    2017-01-01

    Smart system employed CO 2 gas as new trigger has been attracting enormous attention in recent years, but few monomers that are capable of switching their hydrophobicity/hydrophility upon CO 2 stimulation have been reported. A novel CO 2 responsive monomer, 4-vinylbenzyl amidine, is designed and synthesized in this work with N,N -dimethylacetamide dimethyl acetal and 4-vinylbenzyl amine that is prepared through the Gabriel reaction. In bi-phase solvent of n -hexane and water, the monomer dissolves in n -hexane first and then transforms into water upon the CO 2 treatment, indicating a hydrophobic to hydrophilic transition. This transformation is demonstrated as reversible by monitoring the conductivity variation of its wet dimethyl formamide solution during alternate bubbling/removing CO 2 . The protonation of 4-vinylbenzyl amidine upon CO 2 treatment is demonstrated by 1 H NMR which also accounts for the dissolubility change. The reversible addition-fragmentation chain-transfer polymerization of this monomer is also performed, finding the reaction only occurs in glacial acetic acid. The reason can be ascribed to the different radical structure produced in different solvent.

  10. Induction Motor with Switchable Number of Poles and Toroidal Winding

    Directory of Open Access Journals (Sweden)

    MUNTEANU, A.

    2011-05-01

    Full Text Available This paper presents a study of an induction motor provided with toroidal stator winding. The ring-type coils offer a higher versatility in obtaining a different number of pole pairs by means of delta/star and series/parallel connections respectively. As consequence, the developed torque can vary within large limits and the motor can be utilized for applications that require, for example, high load torque values for a short time. The study involves experimental tests and FEM simulation for an induction machine with three configurations of pole pairs. The conclusions attest the superiority of the toroidal winding for certain applications such as electric vehicles or lifting machines.

  11. Switchable adhesion and friction by stimulus responsive polymer brushes

    NARCIS (Netherlands)

    Yu, Yunlong

    2017-01-01

    Controlling friction and adhesion is relevant in nature and in our daily life. Such control can be achieved using stimulus responsive end-anchored polymers forming a brush. These brushes can adapt their physicochemical properties upon changing the surrounding environments, such as temperature,

  12. Photobiological hydrogen production with switchable photosystem-II designer algae

    Science.gov (United States)

    Lee, James Weifu

    2014-02-18

    A process for enhanced photobiological H.sub.2 production using transgenic alga. The process includes inducing exogenous genes in a transgenic alga by manipulating selected environmental factors. In one embodiment inducing production of an exogenous gene uncouples H.sub.2 production from existing mechanisms that would downregulate H.sub.2 production in the absence of the exogenous gene. In other embodiments inducing an exogenous gene triggers a cascade of metabolic changes that increase H.sub.2 production. In some embodiments the transgenic alga are rendered non-regenerative by inducing exogenous transgenes for proton channel polypeptides that are targeted to specific algal membranes.

  13. Light and Redox Switchable Molecular Components for Molecular Electronics

    NARCIS (Netherlands)

    Browne, Wesley R.; Feringa, Bernard

    2010-01-01

    The field of molecular and organic electronics has seen rapid progress in recent years, developing from concept and design to actual demonstration devices in which both single molecules and self-assembled monolayers are employed as light-responsive components. Research in this field has seen

  14. Core-to-core dimers forming switchable mesophase

    Czech Academy of Sciences Publication Activity Database

    Horčic, M.; Svoboda, J.; Novotná, Vladimíra; Pociecha, D.; Gorecka, E.

    2017-01-01

    Roč. 53, č. 18 (2017), s. 2721-2724 ISSN 1359-7345 R&D Projects: GA ČR GA15-02843S Institutional support: RVO:68378271 Keywords : liquid crystals * bent-core mesogens * dimers Subject RIV: JJ - Other Materials OBOR OECD: Nano-materials (production and properties) Impact factor: 6.319, year: 2016

  15. Electrofluorochromic systems : Molecules and materials exhibiting redox-switchable fluorescence

    NARCIS (Netherlands)

    Al-Kutubi, Hanan; Zafarani, H. R.; Rassaei, Liza; Mathwig, Klaus

    2016-01-01

    Electrofluorochromic molecules share the unique property that their fluorescence changes as a function of their oxidation state. This makes them interesting from a fundamental perspective as molecular dyads are designed and synthesized to tune the interplay of electrochemical and luminescent

  16. Threshold Switchable Particles (TSPs) To Control Internal Hemorrhage

    Science.gov (United States)

    2016-09-01

    ing EDAC, polyP, APTES-modified silica, and 2-(N-morpholino)ethanesulfonic acid (MES) [18]. Zeta potential and Fourier transform infrared ( FTIR ...cell culture medium to cell-free multi-well plates revealed that kaolin interfered with the absorbance measurements of multi-well plate-based assays...solution, after which the rate of dye release was monitored spectrophotometrically at 37 °C. For polyP-NOL substrate, absorbance at 400 nm was measured

  17. Threshold-Switchable Particles (TSPs) to Control Internal Hemorrhage

    Science.gov (United States)

    2015-12-01

    the increase in absorbance could be attributed to other underlying processes mechanistically unrelated to autoactivation of FXII such as vesicle...cm-1 with an acoustic phonon at 300 cm-1 and a second order signal at 600 cm-1. Fourier transform infrared spectroscopy ( FTIR ) spectrum for porous...silicon is provided below (Figure 17). The advantage of FTIR over Raman spectroscopy is that there are more infrared active modes, which provide more

  18. Switchable Adhesion Properties From Low and High Tg Polymeric Brushes

    Science.gov (United States)

    Retsos, Haris; Tran, Yvette; Gorodyska, Ganna; Kiriy, Anton; Stamm, Manfred; Creton, Costantino

    2006-03-01

    We investigated the adhesive properties of mono-component and bi-component polymeric brushes chemically grafted on silicon wafers from end-functionalized hydrophilic and/or hydrophobic chains by using the technically simple `grafting to' method. The charge state and the molecular organization of high Tg brushes could be varied reversibly by exposure to appropriate solvents or by varying the grafting density. Adhesive properties were tested against soft pressure-sensitive-adhesives (hydrophobic & hydrophilic) with a probe method. In the case of low Tg brushes, an increase in contact time could selectively improve the adhesion with the soft hydrophobic or hydrophilic adhesive layer. This is due to reorganization of the interface at the molecular scale leading to the formation of entanglements or favorable interactions between the polymer brush and the polymers in the soft adhesive.

  19. Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth

    Science.gov (United States)

    Foster, Jonathan A.; Piepenbrock, Marc-Oliver M.; Lloyd, Gareth O.; Clarke, Nigel; Howard, Judith A. K.; Steed, Jonathan W.

    2010-12-01

    We describe the use of low-molecular-weight supramolecular gels as media for the growth of molecular crystals. Growth of a range of crystals of organic compounds, including pharmaceuticals, was achieved in bis(urea) gels. Low-molecular-weight supramolecular gelators allow access to an unlimited range of solvent systems, in contrast to conventional aqueous gels such as gelatin and agarose. A detailed study of carbamazepine crystal growth in four different bis(urea) gelators, including a metallogelator, is reported. The crystallization of a range of other drug substances, namely sparfloxacin, piroxicam, theophylline, caffeine, ibuprofen, acetaminophen (paracetamol), sulindac and indomethacin, was also achieved in supramolecular gel media without co-crystal formation. In many cases, crystals can be conveniently recovered from the gels by using supramolecular anion-triggered gel dissolution; however, crystals of substances that themselves bind to anions are dissolved by them. Overall, supramolecular gel-phase crystallization offers an extremely versatile new tool in pharmaceutical polymorph screening.

  20. Threshold Switchable Particles (TSP) to Control Internal Hemorrhage

    Science.gov (United States)

    2014-12-01

    Characterization to confirm successful functionalization of SNP with APTES relied on the presence of the amine functional groups via Fourier Transform infrared...within the organelle membrane are protein transporters, like Ca2+ and H+ ATPases and Ca2+/H+ and Na+/H+ exchangers, whose sole function is to maintain a...polyacrylamide gel electrophoresis and commercially- available DNA -based molecular weight markers. We used narrowly sized polyP fractions whose polymer

  1. Solar Energy Windows and Smart IR Switchable Building Technologies

    Energy Technology Data Exchange (ETDEWEB)

    McCarny, James; Kornish, Brian

    2011-09-30

    The three building envelope functions with the largest impact on the energy usage are illumination, energy flux and energy production. In general, these three functions are addressed separately in the building design. A step change toward a zero-energy building can be achieved with a glazing system that combines these three functions and their control into a single unit. In particular, significant value could be realized if illumination into the building is dynamically controlled such that it occurs during periods of low load on the grid (e.g., morning) to augment illumination supplied by interior lights and then to have that same light diverted to PV energy production and the thermal energy rejected during periods of high load on the grid. The objective of this project is to investigate the feasibility of a glazing unit design that integrates these three key functions (illumination and energy flux control, and power production) into a single module.

  2. Reversibly Switchable, pH-Dependent Peptide Ligand Binding via 3,5-Diiodotyrosine Substitutions.

    Science.gov (United States)

    Ngambenjawong, Chayanon; Sylvestre, Meilyn; Gustafson, Heather H; Pineda, Julio Marco B; Pun, Suzie H

    2018-03-05

    Cell type-specific targeting ligands utilized in drug delivery applications typically recognize receptors that are overexpressed on the cells of interest. Nonetheless, these receptors may also be expressed, to varying extents, on off-target cells, contributing to unintended side effects. For the selectivity profile of targeting ligands in cancer therapy to be improved, stimuli-responsive masking of these ligands with acid-, redox-, or enzyme-cleavable molecules has been reported, whereby the targeting ligands are exposed in specific environments, e.g., acidic tumor hypoxia. One possible drawback of these systems lies in their one-time, permanent trigger, which enables the "demasked" ligands to bind off-target cells if released back into the systemic circulation. A promising strategy to address the aforementioned problem is to design ligands that show selective binding based on ionization state, which may be microenvironment-dependent. In this study, we report a systematic strategy to engineer low pH-selective targeting peptides using an M2 macrophage-targeting peptide (M2pep) as an example. 3,5-Diiodotyrosine mutagenesis into native tyrosine residues of M2pep confers pH-dependent binding behavior specific to acidic environment (pH 6) when the amino acid is protonated into the native tyrosine-like state. At physiological pH of 7.4, the hydroxyl group of 3,5-diiodotyrosine on the peptide is deprotonated leading to interruption of the peptide native binding property. Our engineered pH-responsive M2pep (Ac-Y-Î-Î) binds target M2 macrophages more selectively at pH 6 than at pH 7.4. In addition, 3,5-diiodotyrosine substitutions also improve serum stability of the peptide. Finally, we demonstrate pH-dependent reversibility in target binding via a postbinding peptide elution study. The strategy presented here should be applicable for engineering pH-dependent functionality of other targeting peptides with potential applications in physiology-dependent in vivo targeting applications (e.g., targeting hypoxic tumor/inflammation) or in in vitro receptor identification.

  3. Technical Design of Flexible Thin-Film Solar Heating Clothes with Switchable Output Power

    Directory of Open Access Journals (Sweden)

    Zhao Yu Xiao

    2016-01-01

    Full Text Available This research focuses on the research and development of thermal clothes through technical design, by adopting unique removable electronic equipment and applying carbon fiber material to thermal clothes against cold, so as to meet the requirements of active heating and passive warmth retention. Firstly, the specification of power supply system was determined in accordance with the requirements of power system, and the specification of charging system was determined according to the specification of power system. Then circuit system was designed and tested. Fianlly, the electronic device was configured on the clothes appropriately, so that it should be conforms to ergonomic principles, convenient and fast.

  4. Electrocatalytically switchable CO2 capture: first principle computational exploration of carbon nanotubes with pyridinic nitrogen.

    Science.gov (United States)

    Jiao, Yan; Zheng, Yao; Smith, Sean C; Du, Aijun; Zhu, Zhonghua

    2014-02-01

    Carbon nanotubes with specific nitrogen doping are proposed for controllable, highly selective, and reversible CO2 capture. Using density functional theory incorporating long-range dispersion corrections, we investigated the adsorption behavior of CO2 on (7,7) single-walled carbon nanotubes (CNTs) with several nitrogen doping configurations and varying charge states. Pyridinic-nitrogen incorporation in CNTs is found to induce an increasing CO2 adsorption strength with electron injecting, leading to a highly selective CO2 adsorption in comparison with N2 . This functionality could induce intrinsically reversible CO2 adsorption as capture/release can be controlled by switching the charge carrying state of the system on/off. This phenomenon is verified for a number of different models and theoretical methods, with clear ramifications for the possibility of implementation with a broader class of graphene-based materials. A scheme for the implementation of this remarkable reversible electrocatalytic CO2 -capture phenomenon is considered. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Switchable pH-responsive polymeric membranes prepared via block copolymer micelle assembly

    KAUST Repository

    Nunes, Suzana Pereira

    2011-05-24

    A process is described to manufacture monodisperse asymmetric pH-responsive nanochannels with very high densities (pore density >2 × 10 14 pores per m2), reproducible in m2 scale. Cylindric pores with diameters in the sub-10 nm range and lengths in the 400 nm range were formed by self-assembly of metal-block copolymer complexes and nonsolvent-induced phase separation. The film morphology was tailored by taking into account the stability constants for a series of metal-polymer complexes and confirmed by AFM. The distribution of metal-copolymer micelles was imaged by transmission electron microscopy tomography. The pH response of the polymer nanochannels is the strongest reported with synthetic pores in the nm range (reversible flux increase of more than 2 orders of magnitude when switching the pH from 2 to 8) and could be demonstrated by cryo-field emission scanning electron microscopy, SAXS, and ultra/nanofiltration experiments. © 2011 American Chemical Society.

  6. Water resistant surfaces using zinc oxide structured nanorod arrays with switchable wetting property

    OpenAIRE

    Ennaceri, H.; Wang, L.; Erfurt, D.; Riedel, W.; Mangalgiri, G.; Khaldoun, A.; El Kenz, A.; Benyoussef, A.; Ennaoui, A

    2016-01-01

    This study presents an experimental approach for fabricating super hydrophobic coatings based on a dual roughness structure composed of zinc oxide nanorod arrays coated with a sputtered zinc oxide nano layer. The ZnO nanorod arrays were grown by means of a low temperature electrochemical deposition technique 75 C on FTO substrates. The ZnO nanorods show a 002 orientation along the c axis, and have a hexagonal structure, with an average length of 710 nm, and average width of 156 nm. On th...

  7. Photoinduced switchable wettability of bismuth coating with hierarchical dendritic structure between superhydrophobicity and superhydrophilicity

    Energy Technology Data Exchange (ETDEWEB)

    Su, Chunping; Lu, Zhong; Zhao, Huiping; Yang, Hao, E-mail: hyangwit@hotmail.com; Chen, Rong, E-mail: rchenhku@hotmail.com

    2015-10-30

    Graphical abstract: - Highlights: • Hierarchical bismuth nanostructures were synthesized by galvanic replacement reaction. • The bismuth coating shows superhydrophobicity after being modified by stearic acid. • Wetting transition could be realized by alternation of irradiation and modification. - Abstract: Special wettability such as superhydrophobicity and superhydrophilicity has aroused considerable attention in recent years, especially for the surface that can be switched between superhydrophobicity and superhydrophilicity. In this work, hierarchical bismuth nanostructures with hyperbranched dendritic architectures were synthesized via the galvanic replacement reaction between zinc plate and BiCl{sub 3} in ethylene glycol solution, which was composed of a trunk, branches (secondary branch), and leaves (tertiary branch). After being modified by stearic acid, the as-prepared bismuth coating shows superhydrophobicity with a high water contact angle of 164.8° and a low sliding angle of 3°. More importantly, a remarkable surface wettability transition between superhydrophobicity and superhydrophilicity could be easily realized by the alternation of UV–vis irradiation and modification with stearic acid. The tunable wetting behavior of bismuth coating could be used as smart materials to make a great application in practice.

  8. Electrically switchable photonic liquid crystal devices for routing of a polarized light wave

    Science.gov (United States)

    Rushnova, Irina I.; Melnikova, Elena A.; Tolstik, Alexei L.; Muravsky, Alexander A.

    2018-04-01

    The new mode of LC alignment based on photoalignment AtA-2 azo dye where the refractive interface between orthogonal orientations of the LC director exists without voltage and disappeared or changed with critical voltage has been proposed. The technology to fabricate electrically controlled liquid crystal elements for spatial separation and switching of linearly polarized light beams on the basis of the total internal reflection effect has been significantly improved. Its distinctive feature is the application of a composite alignment material comprising two sublayers of Nylon-6 and AtA-2 photoalignment azo dye offering patterned liquid crystal director orientation with high alignment quality value q = 0 . 998. The fabricated electrically controlled spatially structured liquid crystal devices enable implementation of propagation directions separation for orthogonally polarized light beams and their switching with minimal crosstalk.

  9. Switchable 3D liquid crystal grating generated by periodic photo-alignment on both substrates.

    Science.gov (United States)

    Nys, I; Beeckman, J; Neyts, K

    2015-10-21

    A planar liquid crystal (LC) cell is developed in which two photo-alignment layers have been illuminated with respectively a horizontal and a vertical diffraction pattern of interfering left- and right-handed circularly polarized light. In the bulk of the cell, a complex LC configuration is obtained with periodicity in two dimensions. Remarkably, the period of the structure is larger than the period of the interference pattern, indicating that lowering of the symmetry allows a reduction in the elastic energy. The liquid crystal configuration depends on the periodicity of the alignment but also on the thickness of the cell. By applying a voltage over the electrodes, the power going into the different diffracted orders can be tuned. Finite element (FE) simulations based on Q-tensor theory are used to find the 3D equilibrium director distribution, which is used to simulate the near-field transmission profile based on the Jones calculus. A 2D Fourier transform is performed for both the x- and y-component of the transmitted wave to find the diffraction efficiency.

  10. Electrical potential induced switchable wettability of super-aligned carbon nanotube films

    Science.gov (United States)

    Zhang, Guang; Duan, Zheng; Wang, Qinggong; Li, Long; Yao, Wei; Liu, Changhong

    2018-01-01

    Controlling of the wettability of micro-nano scale surfaces not only plays important roles in basic science but also presents some significant applications in interference shielding materials, microfluidics and phase-change heat transfer enhancement, etc. Here, the superhydrophobic super-aligned carbon nanotube (SACNT) films are firstly obtained by the chemical vapor deposition method and the annealing process. Then their wettabilities are in-situ switched by the electrowetting strategy. Specifically, the fascinating transformation of superhydrophobicity to the superhydrophilicity is achieved by exerting external DC voltages across the CNT-liquid interfaces, and the transitions of Cassie-to-Wenzel states are observed on the multilayer SACNT films. In addition, the electrowetting induced salt absorption of the porous SACNT is also reported here. Finally, the threshold voltages of the electrowetting behaviors for different liquids on the SACNT films and unit capacitances across the CNT-liquid interfaces are obtained, which reveal that the SACNT films have much more outstanding electrowetting properties than the previously reported works. Our approach reported here demonstrates that the wettability of SACNT films could be simply, effectively and in-situ controlled by the electrowetting method, which will have many profound implications in numerous applications such as phase-change heat transfer enhancement, optical lens with variable focal length and microfluidics, etc.

  11. Threshold-Switchable Particles (TSP’s) to Control Internal Hemorrhage

    Science.gov (United States)

    2011-12-01

    phosphate following acid digestion of polyP) was performed to quantify polyP concentration against the same reaction that had not undergone glass milk ...Econo-Pac 10 DG Columns. The running phase was borate acid buffer. The reading was for dendrimer. 6    After these initial results, the glass milk ...previously established poly( lactic -co-glycolic acid ) (PLGA) method for drug delivery is shown in Figure A-4 in the Supporting Data below [15]. The silica

  12. Electrically tunable superconducting terahertz metamaterial with low insertion loss and high switchable ratios

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chun; Zhang, Caihong, E-mail: chzhang@nju.edu.cn; Hu, Guoliang; Zhou, Gaochao; Jiang, Shoulu; Jiang, Chengtao; Zhu, Guanghao; Jin, Biaobing, E-mail: bbjin@nju.edu.cn; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng [Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China)

    2016-07-11

    With the emergence and development of artificially structured electromagnetic materials, active terahertz (THz) metamaterial devices have attracted significant attention in recent years. Tunability of transmission is desirable for many applications. For example, short-range wireless THz communications and ultrafast THz interconnects require switches and modulators. However, the tunable range of transmission amplitude of existing THz metamaterial devices is not satisfactory. In this article, we experimentally demonstrate an electrically tunable superconducting niobium nitride metamaterial device and employ a hybrid coupling model to analyze its optical transmission characteristics. The maximum transmission coefficient at 0.507 THz is 0.98 and decreases to 0.19 when the applied voltage increases to 0.9 V. A relative transmittance change of 80.6% is observed, making this device an efficient narrowband THz switch. Additionally, the frequency of the peak is red shifted from 0.507 to 0.425 THz, which means that the device can be used to select the frequency. This study offers an alternative tuning method to existing optical, thermal, magnetic-field, and electric-field tuning, delivering a promising approach for designing active and miniaturized THz devices.

  13. A Switchable 3D-Coverage Phased Array Antenna Package for 5G Mobile Terminals

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Zhang, Shuai

    2016-01-01

    This manuscript proposes a new design of a millimeter-wave (mm-Wave) array antenna package with beam steering characteristic for the fifth generation (5G) mobile applications. In order to achieve a broad 3D scanning coverage of the space with high-gain beams, three identical sub arrays of patch...... antennas have been compactly arranged along the edge region of the mobile phone PCB to form the antenna package. By switching the feeding to one of the sub arrays, the desired direction of coverage can be achieved. The proposed design has >10 dB gain in the upper spherical space, good directivity...

  14. CO2-Switchable Membranes Prepared by Immobilization of CO2-Breathing Microgels.

    Science.gov (United States)

    Zhang, Qi; Wang, Zhenwu; Lei, Lei; Tang, Jun; Wang, Jianli; Zhu, Shiping

    2017-12-20

    Herein, we report the development of a novel CO 2 -responsive membrane system through immobilization of CO 2 -responsive microgels into commercially available microfiltration membranes using a method of dynamic adsorption. The microgels, prepared from soap-free emulsion polymerization of CO 2 -responsive monomer 2-(diethylamino)ethyl methacrylate (DEA), can be reversibly expanded and shrunken upon CO 2 /N 2 alternation. When incorporated into the membranes, this switching behavior was preserved and further led to transformation between microfiltration and ultrafiltration membranes, as indicated from the dramatic changes on water flux and BSA rejection results. This CO 2 -regulated performance switching of membranes was caused by the changes of water transportation channel, as revealed from the dynamic water contact angle tests and SEM observation. This work represents a simple yet versatile strategy for making CO 2 -responsive membranes.

  15. Switchable Photonic Crystals Using One-Dimensional Confined Liquid Crystals for Photonic Device Application.

    Science.gov (United States)

    Ryu, Seong Ho; Gim, Min-Jun; Lee, Wonsuk; Choi, Suk-Won; Yoon, Dong Ki

    2017-01-25

    Photonic crystals (PCs) have recently attracted considerable attention, with much effort devoted to photonic bandgap (PBG) control for varying the reflected color. Here, fabrication of a modulated one-dimensional (1D) anodic aluminum oxide (AAO) PC with a periodic porous structure is reported. The PBG of the fabricated PC can be reversibly changed by switching the ultraviolet (UV) light on/off. The AAO nanopores contain a mixture of photoresponsive liquid crystals (LCs) with irradiation-activated cis/trans photoisomerizable azobenzene. The resultant mixture of LCs in the porous AAO film exhibits a reversible PBG, depending on the cis/trans configuration of azobenzene molecules. The PBG switching is reliable over many cycles, suggesting that the fabricated device can be used in optical and photonic applications such as light modulators, smart windows, and sensors.

  16. Bifurcation properties of nematic liquid crystals exposed to an electric field: Switchability, bistability, and multistability

    KAUST Repository

    Cummings, L. J.

    2013-07-01

    Bistable liquid crystal displays (LCDs) offer the potential for considerable power savings compared with conventional (monostable) LCDs. The existence of two (or more) stable field-free states that are optically distinct means that contrast can be maintained in a display without an externally applied electric field. An applied field is required only to switch the device from one state to the other, as needed. In this paper we examine the basic physical principles involved in generating multiple stable states and the switching between these states. We consider a two-dimensional geometry in which variable surface anchoring conditions are used to control the steady-state solutions and explore how different anchoring conditions can influence the number and type of solutions and whether or not switching is possible between the states. We find a wide range of possible behaviors, including bistability, tristability, and tetrastability, and investigate how the solution landscape changes as the boundary conditions are tuned. © 2013 American Physical Society.

  17. A novel deposition technique for switchable vanadium sesquioxide (V sub 2 O sub 3 ) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Case, F.C. (LTV Missiles and Electronics Group, Research Department, MS WT-50, Dallas, Texas 75265-0003 (USA))

    1991-05-01

    V{sub 2}O{sub 3} is a phase transition material, which, like other oxides of vanadium, undergoes large changes in optical and electrical properties upon switching from the semiconductor to metal state. The transition in V{sub 2}O{sub 3} occurs at temperatures well below that of oxides in the same family, namely near 150--170 K, making it attractive for a number of low-temperature applications. This material has been deposited by a variety of methods, including chemical vapor transport, rf sputtering of a stoichiometric target, pyrolysis, and heat treatment of a sputtered vanadium oxide film. Thin films of this material have also been prepared by the reduction of predeposited VO{sub 2} thin films, requiring the flow of hazardous gases such as hydrogen or carbon monoxide over the sample, which is held at high temperatures in excess of 700 {degree}C. A direct synthesis method for the deposition of high quality V{sub 2}O{sub 3} thin films with low infrared absorption and resistivity change of more than six orders of magnitude is described. Optical, resistivity, and morphological characteristics of this material are discussed.

  18. Light- and pH Switchable Supramolecular Nanoparticles through Electrostatic Self-Assembly

    Science.gov (United States)

    Groehn, Franziska; Willerich, Immanuel

    2011-03-01

    Supramolecular structures that can respond to external triggers are of high interest for example for nanotechnology or drug delivery. Recently we have introduced an approach to electrostatic self-assembly for the formation of supramolecular particles in solution: polyelectrolytes and multivalent stiff organic counterions build well-defined and stable nano-objects. In addition to electrostatics, secondary interactions between counterions such as pi-pi stacking directs the association. Aggregates with narrow size distribution and varying shape such as spheres, cylinders, vesicles and networks result. PH-responsive assemblies can be repeatedly switched ``on'' and ``off'' through pH. Furthermore, light is an elegant, non-invasive stimulus offering possibilities for new functional nanostructures. By electrostatic self-assembly, supramolecular particles can be built the size of which can be triggered by light. For example, assemblies of dendrimer macroions and divalent azobenzene counterions can respond to light with a size increase from 30 nm to 165 nm radius. Detailed characterization by static and dynamic light scattering, AFM, SANS and zeta-potential measurements as well as thermodynamic studies yield insight into driving forces and structural control in the self-assembly process.

  19. A Thermo- and Photo-Switchable Ruthenium Initiator For Olefin Metathesis.

    Science.gov (United States)

    Sashuk, Volodymyr; Danylyuk, Oksana

    2016-05-04

    A ruthenium carbene complex bearing azobenzene functionality is reported. The complex exists in the form of two isomers differing by the size of the chelate ring. Both isomers were isolated by applying kinetic or thermodynamic control during the synthesis and characterized by X-ray diffraction analysis. The isomerization of the complex was studied by UV/Vis spectroscopy. The stable isomer was tested as a catalyst in olefin metathesis. The complex was activated at about 100 °C to promote ring-closing and ring-opening polymerization metathesis reactions. The activation took place also at room temperature under middle ultraviolet radiation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Operation mode switchable charge-trap memory based on few-layer MoS2

    Science.gov (United States)

    Hou, Xiang; Yan, Xiao; Liu, Chunsen; Ding, Shijin; Zhang, David Wei; Zhou, Peng

    2018-03-01

    Ultrathin layered two-dimensional (2D) semiconductors like MoS2 and WSe2 have received a lot of attention because of their excellent electrical properties and potential applications in electronic devices. We demonstrate a charge-trap memory with two different tunable operation modes based on a few-layer MoS2 channel and an Al2O3/HfO2/Al2O3 charge storage stack. Our device shows excellent memory properties under the traditional three-terminal operation mode. More importantly, unlike conventional charge-trap devices, this device can also realize the memory performance with just two terminals (drain and source) because of the unique atomic crystal electrical characteristics. Under the two-terminal operation mode, the erase/program current ratio can reach up to 104 with a stable retention property. Our study indicates that the conventional charge-trap memory cell can also realize the memory performance without the gate terminal based on novel two dimensional materials, which is meaningful for low power consumption and high integration density applications.

  1. In-situ Manipulation and Imaging of Switchable Two-dimensional Electron Gas at Oxide Heterointerfaces

    Science.gov (United States)

    2016-11-30

    ion milling strategy to remove the surface damage layers which are the main cause of the leakage current. After several attempts of optimization...Nonpolar InGaN/GaN Quantum wells”, Ja Kyung Lee, Kyung Song, Christoph T. Koch, Woo Young Jung, Dmitry Tyutyunnikov, Tiannan Yang , Jong Kyu Kim...Chan Gyung Park, Peter A. van Aken, Long-Qing Chen, Young-Min Kim, Sang Ho Oh, submitted to Advanced Functional Materials (2016). f ) provide a

  2. Ultrafast water sensing and thermal imaging by a metal-organic framework with switchable luminescence

    Science.gov (United States)

    Chen, Ling; Ye, Jia-Wen; Wang, Hai-Ping; Pan, Mei; Yin, Shao-Yun; Wei, Zhang-Wen; Zhang, Lu-Yin; Wu, Kai; Fan, Ya-Nan; Su, Cheng-Yong

    2017-06-01

    A convenient, fast and selective water analysis method is highly desirable in industrial and detection processes. Here a robust microporous Zn-MOF (metal-organic framework, Zn(hpi2cf)(DMF)(H2O)) is assembled from a dual-emissive H2hpi2cf (5-(2-(5-fluoro-2-hydroxyphenyl)-4,5-bis(4-fluorophenyl)-1H-imidazol-1-yl)isophthalic acid) ligand that exhibits characteristic excited state intramolecular proton transfer (ESIPT). This Zn-MOF contains amphipathic micropores (manifesting an excellent example of dynamic reversible coordination behaviour. The interconversion between the hydrated and dehydrated phases can turn the ligand ESIPT process on or off, resulting in sensitive two-colour photoluminescence switching over cycles. Therefore, this Zn-MOF represents an excellent PL water-sensing material, showing a fast (on the order of seconds) and highly selective response to water on a molecular level. Furthermore, paper or in situ grown ZnO-based sensing films have been fabricated and applied in humidity sensing (RH<1%), detection of traces of water (<0.05% v/v) in various organic solvents, thermal imaging and as a thermometer.

  3. Prediction of a Large-Gap and Switchable Kane-Mele Quantum Spin Hall Insulator

    Science.gov (United States)

    Marrazzo, Antimo; Gibertini, Marco; Campi, Davide; Mounet, Nicolas; Marzari, Nicola

    2018-03-01

    Fundamental research and technological applications of topological insulators are hindered by the rarity of materials exhibiting a robust topologically nontrivial phase, especially in two dimensions. Here, by means of extensive first-principles calculations, we propose a novel quantum spin Hall insulator with a sizable band gap of ˜0.5 eV that is a monolayer of jacutingaite, a naturally occurring layered mineral first discovered in 2008 in Brazil and recently synthesized. This system realizes the paradigmatic Kane-Mele model for quantum spin Hall insulators in a potentially exfoliable two-dimensional monolayer, with helical edge states that are robust and that can be manipulated exploiting a unique strong interplay between spin-orbit coupling, crystal-symmetry breaking, and dielectric response.

  4. A switchable positive and negative air pressure device for efficient and gentle handling of nanofiber scaffolds

    Science.gov (United States)

    Hotaling, Nathan A.; Khristov, Vladimir; Maminishkis, Arvydas; Bharti, Kapil; Simon, Carl G.

    2017-10-01

    A scaffold handling device (SHD) has been designed that can switch from gentle suction to positive pressure to lift and place nanofiber scaffolds. In tissue engineering laboratories, delicate fibrous scaffolds, such as electrospun nanofiber scaffolds, are often used as substrates for cell culture. Typical scaffold handling procedures include lifting the scaffolds, moving them from one container to another, sterilization, and loading scaffolds into cell culture plates. Using tweezers to handle the scaffolds can be slow, can damage the scaffolds, and can cause them to wrinkle or fold. Scaffolds may also acquire a static charge which makes them difficult to put down as they cling to tweezers. An SHD has been designed that enables more efficient, gentle lifting, and placement of delicate scaffolds. Most of the parts to make the SHD can be purchased, except for the tip which can be 3D-printed. The SHD enables more reliable handling of nanofiber scaffolds that may improve the consistency of biomanufacturing processes.

  5. Switchable directional scattering of electromagnetic radiation with subwavelength asymmetric silicon dimers.

    Science.gov (United States)

    Albella, Pablo; Shibanuma, Toshihiko; Maier, Stefan A

    2015-12-10

    High refractive index dielectric nanoparticles show high promise as a complementary nanophotonics platform due to compared with plasmonic nanostructures low absorption losses and the co-existence of magnetic and electric resonances. Here we explore their use as resonantly enhanced directional scatterers. We theoretically demonstrate that an asymmetric dimer of silicon nanoparticles shows tuneable directional scattering depending on the frequency of excitation. This is due to the interference between electric and magnetic dipoles excited in each nanoparticle, enabling directional control of the scattered light. Interestingly, this control can be achieved regardless of the polarization direction with respect to the dimer axis; however, difference in the polarization can shift the wavelengths at which the directional scattering is achieved. We also explore the application of such an asymmetric nanoantenna as a tuneable routing element in a nanometer scale, suggesting applications in optical nanocircuitry.

  6. Functional helquats: helical cationic dyes with marked, switchable chiroptical properties in the visible region

    Czech Academy of Sciences Publication Activity Database

    Reyes Gutierrez, Paul Eduardo; Jirásek, Michael; Severa, Lukáš; Novotná, P.; Koval, Dušan; Sázelová, Petra; Vávra, Jan; Meyer, A.; Císařová, I.; Šaman, David; Pohl, Radek; Štěpánek, Petr; Slavíček, P.; Coe, B. J.; Hájek, Miroslav; Kašička, Václav; Urbanová, M.; Teplý, Filip

    2015-01-01

    Roč. 51, č. 9 (2015), s. 1583-1586 ISSN 1359-7345 R&D Projects: GA ČR GA13-19213S; GA ČR GA13-32974S; GA ČR(CZ) GAP206/12/0453; GA ČR GA13-03978S; GA ČR GAP208/11/0105 Grant - others:GA ČR(CZ) GA13-34168S; GA AV ČR(CZ) M200551208; GA MŠk(CZ) LM2010005; GA MŠk(CZ) ED3.2.00/08.0144 Institutional support: RVO:61388963 Keywords : helical cationic dyes * pH-switch * chiroptical properties * synthesis Subject RIV: CC - Organic Chemistry Impact factor: 6.567, year: 2015 http://pubs.rsc.org/en/content/articlepdf/2015/cc/c4cc08967g

  7. Giant and switchable surface activity of liquid metal via surface oxidation

    OpenAIRE

    Khan, Mohammad Rashed; Eaker, Collin B.; Bowden, Edmond F.; Dickey, Michael D.

    2014-01-01

    We present a method to control the interfacial energy of a liquid metal via electrochemical deposition (or removal) of an oxide layer on its surface. Unlike conventional surfactants, this approach can tune the interfacial tension of a metal significantly (from ∼7× that of water to near zero), rapidly, and reversibly using only modest voltages. These properties can be harnessed to induce previously unidentified electrohydrodynamic phenomena for manipulating liquid metal alloys based on gallium...

  8. Multivalent Molecular Shuttles – Effect of Increasing the Number of Centers in Switchable Catalysts

    OpenAIRE

    Álvarez González, Celedonio; Barbero, Héctor; Miguel San José, Daniel

    2015-01-01

    Producción Científica A family of three molecular shuttles based upon ammonium/triazolinium salt motifs with one, two, and three catalytic centers were prepared along with their corresponding non‐interlocked threads. The switching process for all rotaxanes was tested through an in situ procedure in solution. Furthermore, their organocatalysis of two Michale‐type reactions by iminium activation was tested to check whether the increase of the number of catalytic centers in the same shuttle i...

  9. Understanding and Controlling Living/Inorganic Interfaces to Enable Reconfigurable Switchable Materials

    Science.gov (United States)

    2018-03-01

    work includes protein engineering of multiple targets (FimH and eCPX), a variety of analytical techniques (including scanning electron microscopy and...distribution is unlimited. iv List of Figures Fig. 1 Demonstration of Au-binding properties by cells expressing mFimH. The above image shows E. coli...Highlights The research focus through the 3-year course of this work has covered multiple binding modes, multiple surfaces, and a variety of factors

  10. High-brightness switchable multi-wavelength remote laser in air

    OpenAIRE

    Yao, Jinping; Zeng, Bin; Xu, Huailiang; Li, Guihua; Chu, Wei; Ni, Jielei; Zhang, Haisu; Chin, See Leang; Cheng, Ya; Xu, Zhizhan

    2011-01-01

    Remote laser in air based on amplified spontaneous emission (ASE) has produced rather well-collimated coherent beams in both backward and forward propagation directions, opening up possibilities for new remote sensing approaches. The remote ASE-based lasers were shown to enable operation either at ~391 and 337 nm using molecular nitrogen or at ~845 nm using molecular oxygen as gain medium, depending on the employed pump lasers. To date, a multi-wavelength laser in air that allows for dynamica...

  11. A Micro Saddle Coil with Switchable Sensitivity for Local High-Resolution Imaging of Luminal Tissue

    Directory of Open Access Journals (Sweden)

    Tetsuji Dohi

    2016-04-01

    Full Text Available This paper reports on a micro saddle coil for local high-resolution magnetic resonance imaging (MRI fabricated by embedding a flexible coil pattern into a polydimethyilsiloxane (PDMS tube. We can change the sensitivity of the micro coil by deforming the shape of the coil from a saddle-shaped mode to a planar-shaped mode. The inductance, the resistance, and the Q-factor of the coil in the saddle-shaped mode were 2.45 μH, 3.31 Ω, and 39.9, respectively. Those of the planar-shaped mode were 3.07 μH, 3.92 Ω, and 42.9, respectively. In MRI acquired in saddle-shaped mode, a large visible area existed around the coil. Although the sensitive area was considerably reduced in the planar-shaped mode, clear MRI images were obtained. The signal-to-noise ratios (SNR of the saddle-shaped and planar-shaped modes were 194.9 and 505.9, respectively, at voxel size of 2.0 × 2.0 × 2.0 mm3 and 11.7 and 37.4, respectively, at voxel size of 0.5 × 0.5 × 1.0 mm3. The sensitivity of the saddle-shaped and the planar-shaped modes were about 3 times and 10 times higher, respectively, than those of the medical head coil at both voxel sizes. Thus, the micro saddle coil enabled large-area imaging and highly sensitive imaging by switching the shape of the coil.

  12. Bioinspired Layer-by-Layer Microcapsules Based on Cellulose Nanofibers with Switchable Permeability

    DEFF Research Database (Denmark)

    Paulraj, Thomas; Riazanova, Anastasia V; Yao, Kun

    2017-01-01

    primary cell walls inspired the capsule wall assembly, because the primary cell walls in plants exhibit high mechanical properties despite being in a highly hydrated state, primarily owing to cellulose microfibrils. The microcapsules (16 ± 4 μm in diameter) were fabricated using the layer......-by-layer technique on sacrificial CaCO3 templates, using plant polysaccharides (pectin, cellulose nanofibers, and xyloglucan) only. In water, the capsule wall was permeable to labeled dextrans with a hydrodynamic diameter of ∼6.6 nm. Upon exposure to NaCl, the porosity of the capsule wall quickly changed allowing...

  13. Electrically switchable organo-inorganic hybrid for a white-light laser source

    Science.gov (United States)

    Huang, Jui-Chieh; Hsiao, Yu-Cheng; Lin, Yu-Ting; Lee, Chia-Rong; Lee, Wei

    2016-06-01

    We demonstrate a spectrally discrete white-light laser device based on a photonic bandgap hybrid, which is composed of a soft photonic crystal; i.e., a layer of dye-doped cholesteric liquid crystal (CLC), sandwiched between two imperfect but identical, inorganic multilayer photonic crystals. With a sole optical pump, a mono-, bi-, or tri-chromatic laser can be obtained and, through the soft photonic crystal regulated by an applied voltage, the hybrid possesses electrical tunability in laser wavelength. The three emitted spectral peaks originate from two bandedges of the CLC reflection band as well as one of the photonic defect modes in dual-mode lasing. Thanks to the optically bistable nature of CLC, such a white-light laser device can operate in quite an energy-saving fashion. This technique has potential to fulfill the present mainstream in the coherent white-light source.

  14. Remote control of tissue interactions via engineered photo-switchable cell surfaces.

    Science.gov (United States)

    Luo, Wei; Pulsipher, Abigail; Dutta, Debjit; Lamb, Brian M; Yousaf, Muhammad N

    2014-09-10

    We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture spheroid tissue assembly in solution and co-culture tissue multilayer assembly on materials was demonstrated by an intercellular photo-oxime ligation that could be remotely cleaved and disassembled on demand. Spatial and temporal control of microtissue structures containing multiple cell types was demonstrated by the generation of patterned multilayers for controlling stem cell differentiation. Remote control of cell interactions via cell surface engineering that allows for real-time manipulation of tissue dynamics may provide tools with the scope to answer fundamental questions of cell communication and initiate new biotechnologies ranging from imaging probes to drug delivery vehicles to regenerative medicine, inexpensive bioreactor technology and tissue engineering therapies.

  15. Remote Control of Tissue Interactions via Engineered Photo-switchable Cell Surfaces

    Science.gov (United States)

    Luo, Wei; Pulsipher, Abigail; Dutta, Debjit; Lamb, Brian M.; Yousaf, Muhammad N.

    2014-01-01

    We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture spheroid tissue assembly in solution and co-culture tissue multilayer assembly on materials was demonstrated by an intercellular photo-oxime ligation that could be remotely cleaved and disassembled on demand. Spatial and temporal control of microtissue structures containing multiple cell types was demonstrated by the generation of patterned multilayers for controlling stem cell differentiation. Remote control of cell interactions via cell surface engineering that allows for real-time manipulation of tissue dynamics may provide tools with the scope to answer fundamental questions of cell communication and initiate new biotechnologies ranging from imaging probes to drug delivery vehicles to regenerative medicine, inexpensive bioreactor technology and tissue engineering therapies. PMID:25204325

  16. Switchable Phased Antenna Array with Passive Elements for 5G Mobile Terminals

    DEFF Research Database (Denmark)

    Syrytsin, Igor A.; Zhang, Shuai; Pedersen, Gert F.

    2017-01-01

    In this paper, a reconfigurable phased antenna array system is constructed for the mobile terminals in the context of 5G communication system. The proposed antenna system operates at the resonance frequency of 28 GHz. The reconfigurability of the antenna element is achieved by using a passive slot...

  17. Stacked-patch antenna with switchable propagating mode for UHF body-centric communications

    NARCIS (Netherlands)

    Scanlon, W.G.; Chandran, A.R.

    2009-01-01

    The ability to electronically switch between off-body and on-body communications is a useful feature for wearable antenna applications. Therefore, we present a novel stacked-patch antenna with a switched propagation mode for body-centric communications at 2.45 GHz. Mounted 2 mm above a muscle-tissue

  18. Bismuth ferrite as low-loss switchable material for plasmonic waveguide modulator.

    Science.gov (United States)

    Babicheva, Viktoriia E; Zhukovsky, Sergei V; Lavrinenko, Andrei V

    2014-11-17

    We propose new designs of plasmonic modulators, which can be used for dynamic signal switching in photonic integrated circuits. We study performance of a plasmonic waveguide modulator with bismuth ferrite as a tunable material. The bismuth ferrite core is sandwiched between metal plates (metal-insulator-metal configuration), which also serve as electrodes. The core changes its refractive index by means of partial in-plane to out-of-plane reorientation of ferroelectric domains in bismuth ferrite under applied voltage. As a result, guided modes change their propagation constant and absorption coefficient, allowing light modulation in both phase and amplitude control schemes. Due to high field confinement between the metal layers, existence of mode cut-offs for certain values of the core thickness, and near-zero material losses in bismuth ferrite, efficient modulation performance is achieved. For the phase control scheme, the π phase shift is provided by a 0.8-μm long device with propagation losses 0.29 dB/μm. For the amplitude control scheme, up to 38 dB/μm extinction ratio with 1.2 dB/μm propagation loss is predicted.

  19. A Switchable Gold Catalyst by Encapsulation in a Self-Assembled Cage

    KAUST Repository

    Jans, Anne C. H.

    2016-08-19

    Dinuclear gold complexes have the ability to interact with one or more substrates in a dual-activation mode, leading to different reactivity and selectivity than their mononuclear relatives. In this contribution, this difference was used to control the catalytic properties of a gold-based catalytic system by site-isolation of mononuclear gold complexes by selective encapsulation. The typical dual-activation mode is prohibited by this catalyst encapsulation, leading to typical behavior as a result of mononuclear activation. This strategy can be used as a switch (on/off) for a catalytic reaction and also permits reversible control over the product distribution during the course of a reaction.

  20. Characterization of a switchable chimeric antigen receptor platform in a pre-clinical solid tumor model.

    Science.gov (United States)

    Pishali Bejestani, Elham; Cartellieri, Marc; Bergmann, Ralf; Ehninger, Armin; Loff, Simon; Kramer, Michael; Spehr, Johannes; Dietrich, Antje; Feldmann, Anja; Albert, Susann; Wermke, Martin; Baumann, Michael; Krause, Mechthild; Bornhäuser, Martin; Ehninger, Gerhard; Bachmann, Michael; von Bonin, Malte

    2017-01-01

    The universal modular chimeric antigen receptor (UniCAR) platform redirects CAR-T cells using a separated, soluble targeting module with a short half-life. This segregation allows precise controllability and flexibility. Herein we show that the UniCAR platform can be used to efficiently target solid cancers in vitro and in vivo using a pre-clinical prostate cancer model which overexpresses prostate stem cell antigen (PSCA). Short-term administration of the targeting module to tumor bearing immunocompromised mice engrafted with human UniCAR-T cells significantly delayed tumor growth and prolonged survival of recipient mice both in a low and high tumor burden model. In addition, we analyzed phenotypic and functional changes of cancer cells and UniCAR-T cells in association with the administration of the targeting module to reveal potential immunoevasive mechanisms. Most notably, UniCAR-T cell activation induced upregulation of immune-inhibitory molecules such as programmed death ligands. In conclusion, this work illustrates that the UniCAR platform mediates potent anti-tumor activity in a relevant in vitro and in vivo solid tumor model.

  1. Bismuth ferrite as low-loss switchable material for plasmonic waveguide modulator

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Zhukovsky, Sergei; Lavrinenko, Andrei

    2014-01-01

    We propose new designs of plasmonic modulators, which can beused for dynamic signal switching in photonic integrated circuits. We studyperformance of a plasmonic waveguide modulator with bismuth ferrite as atunable material. The bismuth ferrite core is sandwiched between metalplates (metal......-insulator-metal configuration), which also serve as electrodes.The core changes its refractive index by means of partial in-plane to out-of-plane reorientation of ferroelectric domains in bismuth ferrite under appliedvoltage. As a result, guided modes change their propagation constant andabsorption coefficient, allowing light...... modulation in both phase andamplitude control schemes. Due to high field confinement between themetal layers, existence of mode cut-offs for certain values of the corethickness, and near-zero material losses in bismuth ferrite, efficientmodulation performance is achieved. For the phase control scheme...

  2. Nanophotonic Modulator with Bismuth Ferrite as Low-loss Switchable Material

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Zhukovsky, Sergei; Lavrinenko, Andrei

    2015-01-01

    We propose a nanophotonic waveguide modulator with bismuth ferrite as a tunable material. Due to near-zero losses in bismuth ferrite, modulation with up to 20 dB/μm extinction ratio and 12 μm propagation length is achieved.......We propose a nanophotonic waveguide modulator with bismuth ferrite as a tunable material. Due to near-zero losses in bismuth ferrite, modulation with up to 20 dB/μm extinction ratio and 12 μm propagation length is achieved....

  3. Hybrid waveguide-bulk multi-path interferometer with switchable amplitude and phase

    Directory of Open Access Journals (Sweden)

    Robert Keil

    2016-11-01

    Full Text Available We design and realise a hybrid interferometer consisting of three paths based on integrated as well as on bulk optical components. This hybrid construction offers a good compromise between stability and footprint on one side and means of intervention on the other. As experimentally verified by the absence of higher-order interferences, amplitude and phase can be manipulated in all paths independently. In conjunction with single photons, the setup can, therefore, be applied for fundamental investigations on quantum mechanics.

  4. Opportunities for switchable solvents for lipid extraction from wet algal biomass: an energy evaluation

    NARCIS (Netherlands)

    Du, Ying; Schuur, Boelo; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

    2015-01-01

    Algae are considered an important sustainable feedstock for lipid extraction to produce food ingredients, cosmetics, pharmaceutical products and biofuels. Next to the costs for cultivation, this route is especially hindered by the energy intensity of drying algae prior to extraction and solvent

  5. Oligo-m-phenyleneoxalamide copper(II) mesocates as electro-switchable ferromagnetic metal-organic wires.

    Science.gov (United States)

    Pardo, Emilio; Ferrando-Soria, Jesús; Dul, Marie-Claire; Lescouëzec, Rodrigue; Journaux, Yves; Ruiz-García, Rafael; Cano, Joan; Julve, Miguel; Lloret, Francesc; Cañadillas-Delgado, Laura; Pasán, Jorge; Ruiz-Pérez, Catalina

    2010-11-15

    Double-stranded copper(II) string complexes of varying nuclearity, from di- to tetranuclear species, have been prepared by the Cu(II)-mediated self-assembly of a novel family of linear homo- and heteropolytopic ligands that contain two outer oxamato and either zero (1 b), one (2 b), or two (3 b) inner oxamidato donor groups separated by rigid 2-methyl-1,3-phenylene spacers. The X-ray crystal structures of these Cu(II) (n) complexes (n=2 (1 d), 3 (2 d), and 4 (3 d)) show a linear array of metal atoms with an overall twisted coordination geometry for both the outer CuN(2)O(2) and inner CuN(4) chromophores. Two such nonplanar all-syn bridging ligands 1 b-3 b in an anti arrangement clamp around the metal centers with alternating M and P helical chiralities to afford an overall double meso-helicate-type architecture for 1 d-3 d. Variable-temperature (2.0-300 K) magnetic susceptibility and variable-field (0-5.0 T) magnetization measurements for 1 d-3 d show the occurrence of S=nS(Cu) (n=2-4) high-spin ground states that arise from the moderate ferromagnetic coupling between the unpaired electrons of the linearly disposed Cu(II) ions (S(Cu)=1/2) through the two anti m-phenylenediamidate-type bridges (J values in the range of +15.0 to 16.8 cm(-1)). Density functional theory (DFT) calculations for 1 d-3 d evidence a sign alternation of the spin density in the meta-substituted phenylene spacers in agreement with a spin polarization exchange mechanism along the linear metal array with overall intermetallic distances between terminal metal centers in the range of 0.7-2.2 nm. Cyclic voltammetry (CV) and rotating-disk electrode (RDE) electrochemical measurements for 1 d-3 d show several reversible or quasireversible one- or two-electron steps that involve the consecutive metal-centered oxidation of the inner and outer Cu(II) ions (S(Cu)=1/2) to diamagnetic Cu(III) ones (S(Cu)=0) at relatively low formal potentials (E values in the range of +0.14 to 0.25 V and of +0.43 to 0.67 V vs. SCE, respectively). Further developments may be envisaged for this family of oligo-m-phenyleneoxalamide copper(II) double mesocates as electroswitchable ferromagnetic 'metal-organic wires' (MOWs) on the basis of their unique ferromagnetic and multicenter redox behaviors.

  6. Solid polymer films exhibiting handedness-switchable, full-color-tunable selective reflection of circularly polarized light.

    Science.gov (United States)

    Nagata, Yuuya; Takagi, Keisuke; Suginome, Michinori

    2014-07-16

    Poly(quinoxaline-2,3-diyl)s bearing (S)-2-methylbutyl, n-butyl, and 8-chlorooctyl groups as side chains were synthesized to fabricate dry solid polymer thin films. These films exhibited selective reflection of right-handed circular polarized light (CPL) in the visible region after annealing in CHCl3 vapor at room temperature. The handedness of reflected CPL was inverted to the left after annealing in 1,2-dichloroethane vapor. It was also found that the color of a particular single film along with the handedness of reflected CPL were fully tuned reversibly, upon exposure of the film to the vapor of various mixtures of chloroform and 1,2-dichloroethane in different ratios.

  7. Taking Orders from Light: Photo-Switchable Working/Inactive Smart Surfaces for Protein and Cell Adhesion.

    Science.gov (United States)

    Zhang, Junji; Ma, Wenjing; He, Xiao-Peng; Tian, He

    2017-03-15

    Photoresponsive smart surfaces are promising candidates for a variety of applications in optoelectronics and sensing devices. The use of light as an order signal provides advantages of remote and noninvasive control with high temporal and spatial resolutions. Modification of the photoswitches with target biomacromolecules, such as peptides, DNA, and small molecules including folic acid derivatives and sugars, has recently become a popular strategy to empower the smart surfaces with an improved detection efficiency and specificity. Herein, we report the construction of photoswitchable self-assembled monolayers (SAMs) based on sugar (galactose/mannose)-decorated azobenzene derivatives and determine their photoswitchable, selective protein/cell adhesion performances via electrochemistry. Under alternate UV/vis irradiation, interconvertible high/low recognition and binding affinity toward selective lectins (proteins that recognize sugars) and cells that highly express sugar receptors are achieved. Furthermore, the cis-SAMs with a low binding affinity toward selective proteins and cells also exhibit minimal response toward unselective protein and cell samples, which offers the possibility in avoiding unwanted contamination and consumption of probes prior to functioning for practical applications. Besides, the electrochemical technique used facilitates the development of portable devices based on the smart surfaces for on-demand disease diagnosis.

  8. A light incident angle switchable ZnO nanorod memristor: reversible switching behavior between two non-volatile memory devices.

    Science.gov (United States)

    Park, Jinjoo; Lee, Seunghyup; Lee, Junghan; Yong, Kijung

    2013-11-26

    A light incident angle selectivity of a memory device is demonstrated. As a model system, the ZnO resistive switching device has been selected. Electrical signal is reversibly switched between memristor and resistor behaviors by modulating the light incident angle on the device. Moreover, a liquid passivation layer is introduced to achieve stable and reversible exchange between the memristor and WORM behaviors. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. HER2 Targeted Breast Cancer Therapy with Switchable "Off/On" Multifunctional "Smart" Magnetic Polymer Core-Shell Nanocomposites.

    Science.gov (United States)

    Vivek, Raju; Thangam, Ramar; Kumar, Selvaraj Rajesh; Rejeeth, Chandrababu; Kumar, Gopal Senthil; Sivasubramanian, Srinivasan; Vincent, Savariar; Gopi, Dhanaraj; Kannan, Soundarapandian

    2016-01-27

    Multifunctional magnetic polymer nanocombinations are gaining importance in cancer nanotheranostics due to their safety and their potential in delivering targeted functions. Herein, we report a novel multifunctional core-shell magnetic polymer therapeutic nanocomposites (NCs) exhibiting pH dependent "Off-On" release of drug against breast cancer cells. The NCs are intact in blood circulation ("Off" state), i.e., at physiological pH, whereas activated ("On" state) at intracellular acidic pH environment of the targeted breast cancer cells. The NCs are prepared by coating the cannonball (iron nanocore) with hydrophobic nanopockets of pH-responsive poly(d,l-lactic-co-glycolic acid) (PLGA) polymer nanoshell that allows efficient loading of therapeutics. Further, the nanocore-polymer shell is stabilized by poly(vinylpyrrolidone) (PVP) and functionalized with a targeting HER2 ligand. The prepared Her-Fe3O4@PLGA-PVP nanocomposites facilitate packing of anticancer drug (Tamoxifen) without premature release in the bloodstream, recognizing the target cells through binding of Herceptin antibody to HER2, a cell surface receptor expressed by breast cancer cells to promote HER2 receptor mediated endocytosis and finally releasing the drug at the intracellular site of tumor cells ("On" state) to induce apoptosis. The therapeutic efficiency of hemo/cytocompatible NCs drug delivery system (DDS) in terms of targeted delivery and sustained release of therapeutic agent against breast cancer cells was substantiated by in vitro and in vivo studies. The multifunctional properties of Her-Tam-Fe3O4@PLGA-PVP NCs may open up new avenues in cancer therapy through overcoming the limitations of conventional cancer therapy.

  10. Parafoveal retinal cone mosaic imaging in children with ultra-compact switchable SLO/OCT handheld probe (Conference Presentation)

    Science.gov (United States)

    LaRocca, Francesco; Nankivil, Derek; DuBose, Theodore B.; Toth, Cynthia A.; Farsiu, Sina; Izatt, Joseph A.

    2016-03-01

    In vivo photoreceptor imaging has enhanced the way vision scientists and ophthalmologists understand the retinal structure, function, and etiology of numerous retinal pathologies. However, the complexity and large footprint of current systems capable of resolving photoreceptors has limited imaging to patients who are able to sit in an upright position and fixate for several minutes. Unfortunately, this excludes an important fraction of patients including bedridden patients, small children, and infants. Here, we show that our dual-modality, high-resolution handheld probe with a weight of only 94 g is capable of visualizing photoreceptors in supine children. Our device utilizes a microelectromechanical systems (MEMS) scanner and a novel telescope design to achieve over an order of magnitude reduction in size compared to similar systems. The probe has a 7° field of view and a lateral resolution of 8 µm. The optical coherence tomography (OCT) system has an axial resolution of 7 µm and a sensitivity of 101 dB. High definition scanning laser ophthalmoscopy (SLO) and OCT images were acquired from children ranging from 14 months to 12 years of age with and without pathology during examination under anesthesia in the operating room. Parafoveal cone imaging was shown using the SLO arm of this device without adaptive optics using a 3° FOV for the first time in children under 4 years old. This work lays the foundation for pediatric research, which will improve understanding of retinal development, maldevelopment and early onset of diseases at the cellular level during the beginning stages of human growth.

  11. Multiplexed and Switchable Release of Distinct Fluids from Microneedle Platforms via Conducting Polymer Nanoactuators for Potential Drug Delivery

    Science.gov (United States)

    Valdés-Ramírez, Gabriela; Windmiller, Joshua R.; Claussen, Jonathan C.; Martinez, Alexandra G.; Kuralay, Filiz; Zhou, Ming; Zhou, Nandi; Polsky, Ronen; Miller, Philip R.; Narayan, Roger; Wang, Joseph

    2013-01-01

    We report on the development of a microneedle-based multiplexed drug delivery actuator that enables the controlled delivery of multiple therapeutic agents. Two individually-addressable channels on a single microneedle array, each paired with its own reservoir and conducting polymer nanoactuator, are used to deliver various permutations of two unique chemical species. Upon application of suitable redox potentials to the selected actuator, the conducting polymer is able to undergo reversible volume changes, thereby serving to release a model chemical agent in a controlled fashion through the corresponding microneedle channels. Time-lapse videos offer direct visualization and characterization of the membrane switching capability and, along with calibration investigations, confirm the ability of the device to alternate the delivery of multiple reagents from individual microneedles of the array with higher precision and temporal resolution than conventional drug delivery actuators. Analytical modeling offers prediction of the volumetric flow rate through a single microneedle and accordingly can be used to assist in the design of subsequent microneedle arrays. The robust solid-state design and lack of mechanical components circumvent reliability issues that challenge fragile conventional microelectromechanical drug delivery devices. This proof-of-concept study demonstrates the potential of the drug delivery actuator system to aid in the rapid administration of multiple therapeutic agents and indicates the potential to counteract diverse biomedical conditions. PMID:24174709

  12. A switchable dual-wavelength erbium-doped fiber laser based on saturable absorber and active optical fiber ring filter

    Science.gov (United States)

    Zhu, Lian-qing; Chen, Qing-shan; Zhao, Ran-ran; Lou, Xiao-ping; He, Wei

    2014-11-01

    A dual-wavelength erbium-doped fiber laser (EDFL) with outstanding stability is presented. In the fiber laser system, two nested active optical fiber ring filters are configured to improve the comb spectrum performance, a saturable absorber is employed to form a gain grating for both filtering and frequency stabilizing, two cascaded fiber Bragg gratings (FBGs) are utilized to achieve dual-wavelength output, and a variable attenuator is arranged to adjust output power. Experimental results illustrate that the peak wavelength drift is less than 3 pm, and a good linear relationship between output power and pump power is realized.

  13. New non-chemically amplified molecular resist design with switchable sensitivity for multi-lithography applications and nanopatterning

    Science.gov (United States)

    Thakur, Neha; Guruprasad Reddy, Pulikanti; Nandi, Santu; Yogesh, Midathala; Sharma, Satinder K.; Pradeep, Chullikkattil P.; Ghosh, Subrata; Gonsalves, Kenneth E.

    2017-12-01

    The development of new photoresist materials for multi-lithography applications is crucial but a challenging task for semiconductor industries. During the last few decades, given the need for new resists to meet the requirements of semiconductor industries, several research groups have developed different resist materials for specific lithography applications. In this context, we have successfully synthesized a new molecular non-chemically amplified resist (n-CAR) (C3) based on the functionalization of aromatic hydroxyl core (4,4‧-(9H-fluorene-9,9-diyl)diphenol) with radiation sensitive sulfonium triflates for various lithography applications. While, micron scale features have been developed using i-line (365 nm) and DUVL (254 nm) exposure tools, electron beam studies on C3 thin films enabled us to pattern 20 nm line features with L/3S (line/space) characteristics on the silicon substrate. The sensitivity and contrast were calculated from the contrast curve analysis as 280 µC cm‑2 and 0.025 respectively. Being an important parameter for any newly developed resists, the line edge roughness (LER) of 30 nm (L/5S) features were calculated, using SUMMIT metrology package, to be 3.66  ±  0.3 nm and found to be within the acceptable range. AFM analysis further confirmed 20 nm line width with smooth pattern wall. No deformation of patterned features was observed during AFM analysis which indicated good adhesion property between patterned resists and silicon substrates.

  14. Indirect amperometric sensing of dopamine using a redox-switchable naphthoquinone-terminated self-assembled monolayer on gold electrode

    International Nuclear Information System (INIS)

    Hammami, Asma; Raouafi, Noureddine; Sahli, Rihab

    2016-01-01

    We report on the design of a simple yet sensitive and selective electrode for amperometric determination of dopamine at a cathodic potential as low as −0.30 V vs. Ag/AgCl. The electrode was obtained by self-assembly of ω-mercaptopropyl naphthoquinone (NQ-SAM) on the surface of a polycrystalline gold electrode. The presence of dopamine induces an increase of the reduction current peak at −0.30 V corresponding to the reduction of naphthoquinone to hydronaphthoquinone. Dopamine and dopamine-quinone accumulate on the surface to form a 3D network linked by hydrogen bonds. Raman and infrared spectroscopy as well as atomic force microscopy confirmed the multilayer formation. The method allows dopamine to be indirectly detected at a working potential that is lower by 0.50 V than the standard oxidation potential at a bare gold electrode. The sensor shows distinct oxidation potentials for dopamine (120 mV), ascorbic acid (280 mV) and uric acid (520 mV) which makes the method fairly selective. The analytical range extends from 1 to 100 μM concentrations of dopamine, and the limits of detection and quantification are 0.040 and 0.134 μM, respectively. (author)

  15. Numerical model (switchable/dual model) of the human head for rigid body and finite elements applications.

    Science.gov (United States)

    Tabacu, Stefan

    2015-01-01

    In this paper, a methodology for the development and validation of a numerical model of the human head using generic procedures is presented. All steps required, starting with the model generation, model validation and applications will be discussed. The proposed model may be considered as a dual one due to its capabilities to switch from deformable to a rigid body according to the application's requirements. The first step is to generate the numerical model of the human head using geometry files or medical images. The required stiffness and damping for the elastic connection used for the rigid body model are identified by performing a natural frequency analysis. The presented applications for model validation are related to impact analysis. The first case is related to Nahum's (Nahum and Smith 1970) experiments pressure data being evaluated and a pressure map generated using the results from discrete elements. For the second case, the relative displacement between the brain and the skull is evaluated according to Hardy's (Hardy WH, Foster CD, Mason, MJ, Yang KH, King A, Tashman S. 2001.Investigation of head injury mechanisms using neutral density technology and high-speed biplanar X-ray. Stapp Car Crash J. 45:337-368, SAE Paper 2001-22-0016) experiments. The main objective is to validate the rigid model as a quick and versatile tool for acquiring the input data for specific brain analyses.

  16. Redox control of capillary filling speed in poly(ferrocenylsilane)-modified microfluidic channels for switchable delay valves

    NARCIS (Netherlands)

    Dos Ramos, Lionel; Lajoinie, Guillaume Pierre Rene; Kieviet, B.D.; de Beer, Sissi; Versluis, Michel; Hempenius, Mark A.; Vancso, Gyula J.

    2016-01-01

    We present a method to reversibly change the wetting of gold-coated microchannel walls, and, as a result, alter the capillary filling speed of water inside such modified microchannels. To this end, we employ the redox-response of surface-anchored poly(ferrocenylsilane) (PFS) films, which allows for

  17. Photo-switchable Donor-Acceptor (D-A) Dyad Interfacial Self-Assembled Monolayers for Organic Photovoltaic Cells

    Science.gov (United States)

    2015-11-05

    Dye-Sensitized Solar Cells," Dyes and Pigments , 107, 9-14, 2014 (DOI: 10.1016/j.dyepig.2014.03.010). Here we report the synthesis and...electron acceptor and anchoring unit for Dye-Sensitized Solar Cells,\\" Dyes and Pigments , 107, 9-14, 2014 (DOI: 10.1016/j.dyepig.2014.03.010). 4. Danny...linked by vinyl-fluorene or vinyl-thiophene spacers for dye-sensitized solar cells,” Dyes and Pigments , 112, 127-137, 2014 (DOI: 10.1016/j.dyepig

  18. Thermally switchable photonic band-edge to random laser emission in dye-doped cholesteric liquid crystals

    Science.gov (United States)

    Ye, Lihua; Wang, Yan; Feng, Yangyang; Liu, Bo; Gu, Bing; Cui, Yiping; Lu, Yanqing

    2018-03-01

    By changing the doping concentration of the chiral agent to adjust the relative position of the reflection band of cholesteric liquid crystals and the fluorescence emission spectrum of the dye, photonic band-edge and random lasing were observed, respectively. The reflection band of the cholesteric phase liquid crystal can also be controlled by adjusting the temperature: the reflection band is blue-shifted with increasing temperature, and a reversible switch from photonic band-edge to random lasing is obtained. Furthermore, the laser line width can be thermally adjusted from 1.1 nm (at 27 °C) to 4.6 nm (at 32.1 °C). A thermally tunable polarization state of a random laser from dual cells was observed, broadening the field of application liquid crystal random lasers.

  19. Ultrathin reduced graphene oxide films as transparent top-contacts for light switchable solid-state molecular junctions

    DEFF Research Database (Denmark)

    Li, Tao; Jevric, Martyn; Hauptmann, Jonas Rahlf

    2013-01-01

    A new type of solid-state molecular junction is introduced, which employs reduced graphene oxide as a transparent top contact that permits a self-assembled molecular monolayer to be photoswitched in situ, while simultaneously enabling charge-transport measurements across the molecules. The electr....... The electrical switching behavior of a less-studied molecular switch, dihydroazulene/vinylheptafulvene, is described, which is used as a test case....

  20. Hydroxylated derivatives of dimethoxy-1,4-benzoquinone as redox switchable earth-alkaline metal ligands and radical scavengers

    OpenAIRE

    Gulaboski, Rubin; Bogeski, Ivan; Mirceski, Valentin; Saul, Stephanie; Pasieka, Bastian; Haeri, Haleh H.; Stefova, Marina; Petreska Stanoeva, Jasmina; Mitrev, Sasa; Hoth, Markus; Kappl, Reinhard

    2013-01-01

    Benzoquinones (BQ) have important functions in many biological processes. In alkaline environments, BQs can be hydroxylated at quinoid ring proton positions. Very little is known about the chemical reaction leading to these structural transformations as well as about the properties of the obtained hydroxyl benzoquinones. We analyzed the behavior of the naturally occurring 2,6-dimethoxy-1,4-benzoquinone under alkaline conditions and show that upon substitution of methoxy-groups, poly-hydroxyl-...

  1. Thermally switchable adhesions of polystyrene-block-poly(n-isopropylacrylamide) copolymer pillar array mimicking climb attitude of geckos

    Science.gov (United States)

    Chen, Jem-Kun; Wang, Jing-Hong; Chang, Jia-Yaw; Fan, Shih-Kang

    2012-09-01

    Inspired by the gecko foot pad, we fabricated polystyrene-block-poly(N-isopropylacrylamide) (PS-b-PNIPAAm) copolymer pillar array to mimic climbing attitude of a gecko, alternately attach to and detach from a surface. The pillar array structure of the PS segment significantly enhances both of the hydrophilic and hydrophobic property of PNIPAAm segment tips at 25 and 50 °C, respectively, which could generate alternating adhesive forces of approximately 120 and 11 nN. The dramatic change in adhesive and friction force difference at 25 and 50 °C may guide the design of bio-inspired artificial analogues, which could approach gecko's climbing behavior.

  2. Extensively Reversible Thermal Transformations of a Bistable, Fluorescence-Switchable Molecular Solid: Entry into Functional Molecular Phase-Change Materials.

    Science.gov (United States)

    Srujana, P; Radhakrishnan, T P

    2015-06-15

    Functional phase-change materials (PCMs) are conspicuously absent among molecular materials in which the various attributes of inorganic solids have been realized. While organic PCMs are primarily limited to thermal storage systems, the amorphous-crystalline transformation of materials like Ge-Sb-Te find use in advanced applications such as information storage. Reversible amorphous-crystalline transformations in molecular solids require a subtle balance between robust supramolecular assembly and flexible structural elements. We report novel diaminodicyanoquinodimethanes that achieve this transformation by interlinked helical assemblies coupled with conformationally flexible alkoxyalkyl chains. They exhibit highly reversible thermal transformations between bistable (crystalline/amorphous) forms, along with a prominent switching of the fluorescence emission energy and intensity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Strain effects in topological insulators: Topological order and the emergence of switchable topological interface states in Sb2Te3/Bi2Te3 heterojunctions

    Science.gov (United States)

    Aramberri, H.; Muñoz, M. C.

    2017-05-01

    We investigate the effects of strain on the topological order of the Bi2Se3 family of topological insulators by ab initio first-principles methods. Strain can induce a topological phase transition and we present the phase diagram for the 3D topological insulators, Bi2Te3 , Sb2Te3 , Bi2Se3 , and Sb2Se3 , under combined uniaxial and biaxial strain. Their phase diagram is universal and shows metallic and insulating phases, both topologically trivial and nontrivial. In particular, uniaxial tension can drive the four compounds into a topologically trivial insulating phase. We propose a Sb2Te3/Bi2Te3 heterojunction in which a strain-induced topological interface state arises in the common gap of this normal insulator-topological insulator heterojunction. Unexpectedly, the interface state is confined in the topologically trivial subsystem and is physically protected from ambient impurities. It can be switched on or off by means of uniaxial strain and therefore Sb2Te3 /Bi2Te3 heterojunctions provide a topological system which hosts tunable robust helical interface states with promising spintronic applications.

  4. Charge collection microscopy of in-situ switchable PRAM line cells in a scanning electron microscope : Technique development and unique observations

    NARCIS (Netherlands)

    Oosthoek, J. L. M.; Schuitema, R. W.; ten Brink, G. H.; Gravesteijn, D. J.; Kooi, B. J.

    An imaging method has been developed based on charge collection in a scanning electron microscope (SEM) that allows discrimination between the amorphous and crystalline states of Phase-change Random Access Memory (PRAM) line cells. During imaging, the cells are electrically connected and can be

  5. Solvent-switchable continuous-breathing behaviour in a diamondoid metal-organic framework and its influence on CO2 versus CH4 selectivity

    Science.gov (United States)

    Carrington, Elliot J.; McAnally, Craig A.; Fletcher, Ashleigh J.; Thompson, Stephen P.; Warren, Mark; Brammer, Lee

    2017-09-01

    Understanding the behaviour of flexible metal-organic frameworks (MOFs)—porous crystalline materials that undergo a structural change upon exposure to an external stimulus—underpins their design as responsive materials for specific applications, such as gas separation, molecular sensing, catalysis and drug delivery. Reversible transformations of a MOF between open- and closed-pore forms—a behaviour known as 'breathing'—typically occur through well-defined crystallographic transitions. By contrast, continuous breathing is rare, and detailed characterization has remained very limited. Here we report a continuous-breathing mechanism that was studied by single-crystal diffraction in a MOF with a diamondoid network, (Me2NH2)[In(ABDC)2] (ABDC, 2-aminobenzene-1,4-dicarboxylate). Desolvation of the MOF in two different solvents leads to two polymorphic activated forms with very different pore openings, markedly different gas-adsorption capacities and different CO2 versus CH4 selectivities. Partial desolvation introduces a gating pressure associated with CO2 adsorption, which shows that the framework can also undergo a combination of stepped and continuous breathing.

  6. Time Resolved Spectroscopic Studies on a Novel Synthesized Photo-Switchable Organic Dyad and Its Nanocomposite Form in Order to Develop Light Energy Conversion Devices.

    Science.gov (United States)

    Dutta Pal, Gopa; Paul, Abhijit; Yadav, Somnath; Bardhan, Munmun; De, Asish; Chowdhury, Joydeep; Jana, Aindrila; Ganguly, Tapan

    2015-08-01

    UV-vis absorption, steady state and time resolved spectroscopic investigations in pico and nanosecond time domain were made in the different environments on a novel synthesized dyad, 3-(2-methoxynaphthalen-1-yl)-1-(4-methoxyphenyl)prop-2-en-1-one (MNTMA) in its pristine form and when combined with gold (Au) nanoparticles i.e., in its nanocomposite structure. Both steady state and time resolved measurements coupled with the DFT calculations performed by using Gaussian 03 suit of software operated in the linux operating system show that though the dyad exhibits mainly the folded conformation in the ground state but on photoexcitation the nanocomposite form of dyad prefers to be in elongated structure in the excited state indicating its photoswitchable nature. Due to the predominancy of elongated isomeric form of the dyad in the excited state in presence of Au Nps, it appears that the dyad MNTMA may behave as a good light energy converter specially in its nanocomposite form. As larger charge separation rate (kcs ~ 4 x 10(8) s-1) is found relative to the rate associated with the energy wasting charge recombination processes (kcR ~ 3 x 10(5) s-1) in the nanocomposite form of the dyad, it demonstrates the suitability of constructing the efficient light energy conversion devices with Au-dyad hybrid nanomaterials.

  7. Switchable field-tuned control of magnetic domain wall pinning along Co microwires by 3D e-beam lithographed structures

    International Nuclear Information System (INIS)

    Blanco-Roldán, C.; Quirós, C.; Rodriguez-Rodriguez, G.; Vélez, M.; Martín, J.I.; Alameda, J.M.

    2016-01-01

    Three-dimensional magnetic circuits composed of Co microwires crossed by elevated Co bridges have been patterned on Si substrate by e-beam lithography and lift-off process. The lithographic procedure includes a double resist procedure that optimizes the shape of the bridge, so that 200 nm air gaps can be routinely achieved in between the wire and bridge elements. Microwire magnetization reversal processes have been analyzed by magneto-optical Kerr effect microscopy with different remanent bridge configurations. When the Co bridge is magnetized along the in-plane direction parallel to the wire axis, its stray field induces a marked pinning effect on domain wall propagation along the wire below it, even without being in contact. Changing the sign of the remanent state of the bridge, domain wall pinning can be selected to occur in either the ascending or descending branches of the wire hysteresis loop. Thus, these wire-bridge 3D circuits provide a simple system for tunable domain wall pinning controllable through the pre-recorded bridge remanent state. - Highlights: • Electron beam lithography is used to fabricate a tridimensional magnetic circuit. • Proposed circuit is made of a Co bridge overcrossing a non-contacted Co microwire. • Domain wall propagation can be controlled by previous magnetization of the system. • Domain wall pinning in the wire depends on the applied magnetic field sign.

  8. High-efficiency exfoliation of layered materials into 2D nanosheets in switchable CO2/Surfactant/H2O system

    OpenAIRE

    Nan Wang; Qun Xu; Shanshan Xu; Yuhang Qi; Meng Chen; Hongxiang Li; Buxing Han

    2015-01-01

    Layered materials present attractive and important properties due to their two-dimensional (2D) structure, allowing potential applications including electronics, optoelectronics, and catalysis. However, fully exploiting the outstanding properties will require a method for their efficient exfoliation. Here we present that a series of layered materials can be successfully exfoliated into single- and few-layer nanosheets using the driving forces coming from the phase inversion, i.e., from micell...

  9. High-efficiency exfoliation of layered materials into 2D nanosheets in switchable CO2/Surfactant/H2O system

    Science.gov (United States)

    Wang, Nan; Xu, Qun; Xu, Shanshan; Qi, Yuhang; Chen, Meng; Li, Hongxiang; Han, Buxing

    2015-11-01

    Layered materials present attractive and important properties due to their two-dimensional (2D) structure, allowing potential applications including electronics, optoelectronics, and catalysis. However, fully exploiting the outstanding properties will require a method for their efficient exfoliation. Here we present that a series of layered materials can be successfully exfoliated into single- and few-layer nanosheets using the driving forces coming from the phase inversion, i.e., from micelles to reverse micelles in the emulsion microenvironment built by supercritical carbon dioxide (SC CO2). The effect of variable experimental parameters including CO2 pressure, ethanol/water ratio, and initial concentration of bulk materials on the exfoliation yield have been investigated. Moreover, we demonstrate that the exfoliated 2D nanosheets have their worthwhile applications, for example, graphene can be used to prepare conductive paper, MoS2 can be used as fluorescent label to perform cellular labelling, and BN can effectively reinforce polymers leading to the promising mechanical properties.

  10. A Fast pH-Switchable and Self-Healing Supramolecular Hydrogel Carrier for Guided, Local Catheter Injection in the Infarcted Myocardium

    OpenAIRE

    Bastings, Maartje M. C.; Koudstaal, Stefan; Kieltyka, Roxanne E.; Nakano, Yoko; Pape, A. C. H.; Feyen, Dries A. M.; van Slochteren, Frebus J.; Doevendans, Pieter A.; Sluijter, Joost P. G.; Meijer, E. W.; Chamuleau, Steven A. J.; Dankers, Patricia Y. W.

    2014-01-01

    Minimally invasive intervention strategies after myocardial infarction use state-of-the-art catheter systems that are able to combine mapping of the infarcted area with precise, local injection of drugs. To this end, catheter delivery of drugs that are not immediately pumped out of the heart is still challenging, and requires a carrier matrix that in the solution state can be injected through a long catheter, and instantaneously gelates at the site of injection. To address this unmet need, a ...

  11. Light-Switchable Hemithioindigo-Hemistilbene-Containing Peptides : Ultrafast Spectroscopy of the Z -> E Isomerization of the Chromophore and the Structural Dynamics of the Peptide Moiety

    NARCIS (Netherlands)

    Regner, N.; Herzog, T. T.; Haiser, K.; Hoppmann, C.; Beyermann, M.; Sauermann, J.; Engelhard, M.; Cordes, T.; Rueck-Braun, K.; Zinth, W.; Rück-Braun, K.

    2012-01-01

    Two hemithioindigo-hemistilbene (HTI) derivatives, designed to operate as structural switches in peptides, as well as two HTI peptides are characterized by ultrafast spectroscopy in the visible and the infrared. The two HTI switches follow the reaction scheme published for other HTI compounds with a

  12. Switchable dual-wavelength SOA-based fiber laser with continuous tunability over the C-band at room-temperature.

    Science.gov (United States)

    Ummy, M A; Madamopoulos, N; Razani, M; Hossain, A; Dorsinville, R

    2012-10-08

    We propose and demonstrate a simple compact, inexpensive, SOA-based, dual-wavelength tunable fiber laser, that can potentially be used for photoconductive mixing and generation of waves in the microwave and THz regions. A C-band semiconductor optical amplifier (SOA) is placed inside a linear cavity with two Sagnac loop mirrors at its either ends, which act as both reflectors and output ports. The selectivity of dual wavelengths and the tunability of the wavelength difference (Δλ) between them is accomplished by placing a narrow bandwidth (e.g., 0.3 nm) tunable thin film-based filter and a fiber Bragg grating (with bandwidth 0.28 nm) inside the loop mirror that operates as the output port. A total output power of + 6.9 dBm for the two wavelengths is measured and the potential for higher output powers is discussed. Optical power and wavelength stability are measured at 0.33 dB and 0.014 nm, respectively.

  13. Wavelength-switchable and stable-ring-cavity, erbium-doped fiber laser based on Mach–Zehnder interferometer and tunable filter

    Science.gov (United States)

    He, Wei; Zhu, Lianqing; Dong, Mingli; Lou, Xiaoping; Luo, Fei

    2018-04-01

    This paper proposes and tests a ring cavity-based, erbium-doped fiber laser that incorporates a Mach–Zehnder interferometer and tunable filter. A four-m-long erbium-doped fiber was selected as the gain medium. The all-fiber Mach–Zehnder interferometer was composed of two 2  ×  2 optical couplers, and the tunable filter was used as wavelength reflector. A lasing threshold of 103 mW was used in the experiment, and the tunable laser with stable single and dual wavelengths was implemented by adjusting the tunable filter. The channel spacing was 0.6 nm within the range 1539.4–1561.6 nm, where the power difference between the lines was less than 0.4 dB. The side-mode suppression ratio was higher than 36 dB and the 3 dB linewidth was 0.02 nm. When a single-wavelength laser was implemented at 1557.4 nm, the power fluctuations were lower than 0.34 dB within 20 min of scan time. When lasers at wavelengths of 1558.6 nm and 1559.2 nm were simultaneously applied, the power shifts were lower than 0.29 dB and 0.43 dB, respectively, at room temperature.

  14. A Switchable Magnetic Low-Index Metamaterial for Use in a Dynamically Reconfigurable Beam-Scanning Lens Antenna with a Single Feed

    Science.gov (United States)

    2014-12-01

    Cascade port 6 to lumped elt : cascadesparams Reorder and ground port 6: snplsmp F1:1 1 F1:2 2 F2:1 3 F2:2 4 Cascade port 5 to lumped element...34Transformation optical designs for wave collimators, flat lenses and right-angle bends," New Journal of Physics, vol. 10, no. 11, pp. 115023/1-13, Nov...D. H. Werner, and P. L. Werner, "Reconfigurable and tunable metamaterials: a review of the theory and ap- plications," International Journal of

  15. Maximizing Lipid Yield in Neochloris oleoabundans Algae Extraction by Stressing and Using Multiple Extraction Stages with N-Ethylbutylamine as Switchable Solvent

    NARCIS (Netherlands)

    Du, Ying; Schuur, Boelo; Brilman, Derk W.F.

    2017-01-01

    (Graph Presented) The extraction yield of lipids from nonbroken Neochloris oleoabundans was maximized by using multiple extraction stages and using stressed algae. Experimental parameters that affect the extraction were investigated. The study showed that with wet algae (at least) 18 h extraction

  16. pH-triggered surface charge-switchable polymer micelles for the co-delivery of paclitaxel/disulfiram and overcoming multidrug resistance in cancer

    Directory of Open Access Journals (Sweden)

    Huo Q

    2017-12-01

    Full Text Available Qiang Huo,1,* Jianhua Zhu,1,2,* Yimin Niu,3 Huihui Shi,2 Yaxiang Gong,2 Yang Li,2 Huihui Song,4 Yang Liu2 1School of Pharmacy, Bengbu Medical College, Bengbu, 2School of Pharmacy, Nanjing Medical University, 3Department of Pharmacy, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, 4Yangtze River Pharmaceutical Group, Taizhou, People’s Republic of China *These authors contributed equally to this work Abstract: Multidrug resistance (MDR remains a major challenge for providing effective chemotherapy for many cancer patients. To address this issue, we report an intelligent polymer-based drug co-delivery system which could enhance and accelerate cellular uptake and reverse MDR. The nanodrug delivery systems were constructed by encapsulating disulfiram (DSF, a P-glycoprotein (P-gp inhibitor, into the hydrophobic core of poly(ethylene glycol-block-poly(l-lysine (PEG-b-PLL block copolymer micelles, as well as 2,3-dimethylmaleic anhydride (DMA and paclitaxel (PTX were grafted on the side chain of l-lysine simultaneously. The surface charge of the drug-loaded micelles represents as negative in plasma (pH 7.4, which is helpful to prolong the circulation time, and in a weak acid environment of tumor tissue (pH 6.5–6.8 it can be reversed to positive, which is in favor of their entering into the cancer cells. In addition, the carrier could release DSF and PTX successively inside cells. The results of in vitro studies show that, compared to the control group, the DSF and PTX co-loaded micelles with charge reversal exhibits more effective cellular uptake and significantly increased cytotoxicity of PTX to MCF-7/ADR cells which may be due to the inhibitory effect of DSF on the efflux function of P-gp. Accordingly, such a smart pH-sensitive nanosystem, in our opinion, possesses significant potential to achieve combinational drug delivery and overcome drug resistance in cancer therapy. Keywords: pH response, charge reversal, multidrug resistance, paclitaxel, disulfiram

  17. Switchable field-tuned control of magnetic domain wall pinning along Co microwires by 3D e-beam lithographed structures

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Roldán, C., E-mail: c.blanco@cinn.es [Departamento de Física, Universidad de Oviedo, Avenida Calvo Sotelo s/n, 33007 Oviedo (Spain); Centro de Investigación en Nanomateriales y Nanotecnología CINN (CSIC, Universidad de Oviedo), Avenida de la Vega 4-6, 33940 El Entrego (Spain); Quirós, C.; Rodriguez-Rodriguez, G.; Vélez, M.; Martín, J.I.; Alameda, J.M. [Departamento de Física, Universidad de Oviedo, Avenida Calvo Sotelo s/n, 33007 Oviedo (Spain); Centro de Investigación en Nanomateriales y Nanotecnología CINN (CSIC, Universidad de Oviedo), Avenida de la Vega 4-6, 33940 El Entrego (Spain)

    2016-02-15

    Three-dimensional magnetic circuits composed of Co microwires crossed by elevated Co bridges have been patterned on Si substrate by e-beam lithography and lift-off process. The lithographic procedure includes a double resist procedure that optimizes the shape of the bridge, so that 200 nm air gaps can be routinely achieved in between the wire and bridge elements. Microwire magnetization reversal processes have been analyzed by magneto-optical Kerr effect microscopy with different remanent bridge configurations. When the Co bridge is magnetized along the in-plane direction parallel to the wire axis, its stray field induces a marked pinning effect on domain wall propagation along the wire below it, even without being in contact. Changing the sign of the remanent state of the bridge, domain wall pinning can be selected to occur in either the ascending or descending branches of the wire hysteresis loop. Thus, these wire-bridge 3D circuits provide a simple system for tunable domain wall pinning controllable through the pre-recorded bridge remanent state. - Highlights: • Electron beam lithography is used to fabricate a tridimensional magnetic circuit. • Proposed circuit is made of a Co bridge overcrossing a non-contacted Co microwire. • Domain wall propagation can be controlled by previous magnetization of the system. • Domain wall pinning in the wire depends on the applied magnetic field sign.

  18. Maximizing Lipid Yield in Neochloris oleoabundans Algae Extraction by Stressing and Using Multiple Extraction Stages with N-Ethylbutylamine as Switchable Solvent

    Science.gov (United States)

    2017-01-01

    The extraction yield of lipids from nonbroken Neochloris oleoabundans was maximized by using multiple extraction stages and using stressed algae. Experimental parameters that affect the extraction were investigated. The study showed that with wet algae (at least) 18 h extraction time was required for maximum yield at room temperature and a solvent/feed ratio of 1:1 (w/w). For fresh water (FW), nonstressed, nonbroken Neochloris oleoabundans, 13.1 wt % of lipid extraction yield (based on dry algae mass) was achieved, which could be improved to 61.3 wt % for FW stressed algae after four extractions, illustrating that a combination of stressing the algae and applying the solvent N-ethylbutylamine in multiple stages of extraction results in almost 5 times higher yield and is very promising for further development of energy-efficient lipid extraction technology targeting nonbroken wet microalgae. PMID:28781427

  19. On the strain coupling across vertical interfaces of switchable BiFeO3-CoFe2O4 multiferroic nanostructures

    Science.gov (United States)

    Dix, N.; Muralidharan, R.; Guyonnet, J.; Warot-Fonrose, B.; Varela, M.; Paruch, P.; Sánchez, F.; Fontcuberta, J.

    2009-08-01

    In magnetoelectrically coupled CoFe2O4-BiFeO3 nanostructures vertical and lateral lattice parameters of both phases are determined. We find that the in-plane lattice parameter of CoFe2O4 is fully relaxed whereas it presents compressive strain along the out-of-plane direction. Although the CoFe2O4-BiFeO3 interface is semicoherent, CoFe2O4 out-of-plane lattice strain is not relaxed after selective removal of the matrix and thus it is of nonelastic origin. In spite of the absence of elastic residual strain caused by CoFe2O4-BiFeO3 interfaces, the two phases are mechanically coupled as demonstrated by the electrical switching of the magnetization.

  20. Thermally Switchable Fluorescence Resonance Energy Transfer via Reversible Diels-Alder Reaction of π-Conjugated Oligo-(Phenylene Ethynylene)s.

    Science.gov (United States)

    Ahner, Johannes; Dahlke, Jan; Pretzel, David; Schubert, Ulrich S; Dietzek, Benjamin; Hager, Martin D

    2018-04-01

    The combination of reversible, dynamic covalent bonds and π-conjugated oligo-(phenylene ethynylene)s is utilized for exchange reactions between two acceptors and one donor containing copolymer in the solid state upon thermal treatment. The specific molecular design of the polymers allows upon thermally triggering the reshuffling of the π-conjugated donor and acceptor moieties. Depending on the nature of the acceptor, an increased and a decreased fluorescence resonance energy transfer (FRET), respectively, can be observed for the mixing of the copolymers or the demixing of a donor-acceptor copolymer. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Synthesis of Thermally Switchable Chromatographic Materials with Immobilized Ti4+ for Enrichment of Phosphopeptides by Reversible Addition Fragmentation Chain Transfer Polymerization

    Science.gov (United States)

    Wang, Di; Cao, Zhihan; Pang, Xinzhu; Deng, Yulin; Li, Bo; Dai, Rongji

    2018-01-01

    Reversible phosphorylation of proteins is one of the most crucial types of post-translational modifications (PTMs). And it shows significant work in diversified biological processes. However, the separation technology of phosphorylated peptides is still an analytical challenge in phosphoproteomics, because phosphopeptides are alway in low stoichiometry. Thus, enrichment of phosphopeptides before detection is indispensable. In this study, a novel temperature regulated separation protocol was developed. Silica@p (NIPAAm-co-IPPA)-Ti4+, a new Ti(IV)-IMAC (Immobilized Metal Affinity chromatography) materials was synthesized by reversible addition fragmentation chain transfer polymerization (RAFT). By the unique thermally responsive properties of poly(N-isopropylacrylamide) (PNIPAAm), the captured phosphorylated peptides could be released by changing temperature only without applying any other eluant which could damage the phosphopeptides. We employed isopropanol phosphonic acid (IPPA) as an IMAC ligand for the immobilization of Ti(IV) which could increase the specific adsorption of phosphopeptides. The enrichment and release properties were examined by treatment with pyridoxal 5’-phosphate (PLP) and casein phosphopeptides (CPP). Two phosphorylated compounds above have temperature-stimulated binding to Ti4+. Finally, silica@p (NIPAAm-co-IPPA)-Ti4+ was successfully employed in pretreatment of phosphopeptides in a tryptic digest of a-casein and human serum albumin (HSA). The results indicated a great potential of this new temperature-responsive material in phosphoproteomics study.

  2. 78 FR 5075 - Energy Conservation Program: Test Procedure for Set-Top Boxes

    Science.gov (United States)

    2013-01-23

    ... extending devices, and possibly the entire category of home automation, security and smart grid products... reflector lamps: Lamps that have essentially identical light output and electrical characteristics...

  3. Novel Material Systems and Methodologies for Transient Thermal Management

    Data.gov (United States)

    National Aeronautics and Space Administration — Advancements in design and development of evaluation methodologies were made in transient thermal testing. Development of multifunctional and thermally switchable...

  4. A Novel Type of Battery-Supercapacitor Hybrid Device with Highly Switchable Dual Performances Based on a Carbon Skeleton/Mg2Ni Free-Standing Hydrogen Storage Electrode.

    Science.gov (United States)

    Li, Na; Du, Yi; Feng, Qing-Ping; Huang, Gui-Wen; Xiao, Hong-Mei; Fu, Shao-Yun

    2017-12-27

    The sharp proliferation of high power electronics and electrical vehicles has promoted growing demands for power sources with both high energy and power densities. Under these circumstances, battery-supercapacitor hybrid devices are attracting considerable attention as they combine the advantages of both batteries and supercapacitors. Here, a novel type of hybrid device based on a carbon skeleton/Mg 2 Ni free-standing electrode without the traditional nickel foam current collector is reported, which has been designed and fabricated through a dispersing-freeze-drying method by employing reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNTs) as a hybrid skeleton. As a result, the Mg 2 Ni alloy is able to deliver a high discharge capacity of 644 mAh g -1 and, more importantly, a high cycling stability with a retention of over 78% after 50 charge/discharge cycles have been achieved, which exceeds almost all the results ever reported on the Mg 2 Ni alloy. Simultaneously, the electrode could also exhibit excellent supercapacitor performances including high specific capacities (296 F g -1 ) and outstanding cycling stability (100% retention after 100 cycles). Moreover, the hybrid device can switch between battery and supercapacitor modes immediately as needed during application. These features make the C skeleton/alloy electrode a highly promising candidate for battery-supercapacitor hybrid devices with high power/energy density and favorable cycling stability.

  5. Switchable and tunable film bulk acoustic resonator fabricated using barium strontium titanate active layer and Ta{sub 2}O{sub 5}/SiO{sub 2} acoustic reflector

    Energy Technology Data Exchange (ETDEWEB)

    Sbrockey, N. M., E-mail: sbrockey@structuredmaterials.com; Tompa, G. S. [Structured Materials Industries, Inc., Piscataway, New Jersey 08854 (United States); Kalkur, T. S.; Mansour, A. [Department of Electrical and Computer Engineering, Colorado State University at Colorado Springs, Colorado Springs, Colorado 80933 (United States); Khassaf, H.; Yu, H.; Aindow, M.; Alpay, S. P. [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2016-08-01

    A solidly mounted acoustic resonator was fabricated using a Ba{sub 0.60}Sr{sub 0.40}TiO{sub 3} (BST) film deposited by metal organic chemical vapor deposition. The device was acoustically isolated from the substrate using a Bragg reflector consisting of three pairs of Ta{sub 2}O{sub 5}/SiO{sub 2} layers deposited by chemical solution deposition. Transmission electron microscopy verified that the Bragg reflector was not affected by the high temperatures and oxidizing conditions necessary to process high quality BST films. Electrical characterization of the resonator demonstrated a quality factor (Q) of 320 and an electromechanical coupling coefficient (K{sub t}{sup 2}) of 7.0% at 11 V.

  6. Cost-effectiveness of different interferon beta products for relapsing-remitting and secondary progressive multiple sclerosis: Decision analysis based on long-term clinical data and switchable treatments.

    Science.gov (United States)

    Nikfar, Shekoufeh; Kebriaeezadeh, Abbas; Dinarvand, Rassoul; Abdollahi, Mohammad; Sahraian, Mohammad-Ali; Henry, David; Akbari Sari, Ali

    2013-06-22

    Multiple sclerosis (MS) is a highly debilitating immune mediated disorder and the second most common cause of neurological disability in young and middle-aged adults. Iran is amongst high MS prevalence countries (50/100,000). Economic burden of MS is a topic of important deliberation in economic evaluations study. Therefore determining of cost-effectiveness interferon beta (INF β) and their copied biopharmaceuticals (CBPs) and biosimilars products is significant issue for assessment of affordability in Lower-middle-income countries (LMICs). A literature-based Markov model was developed to assess the cost-effectiveness of three INF βs products compared with placebo for managing a hypothetical cohort of patients diagnosed with relapsing remitting MS (RRMS) in Iran from a societal perspective. Health states were based on the Kurtzke Expanded Disability Status Scale (EDSS). Disease progression transition probabilities for symptom management and INF β therapies were obtained from natural history studies and multicenter randomized controlled trials and their long term follow up for RRMS and secondary progressive MS (SPMS). A cross sectional study has been developed to evaluate cost and utility. Transitions among health states occurred in 2-years cycles for fifteen cycles and switching to other therapies was allowed. Calculations of costs and utilities were established by attachment of decision trees to the overall model. The incremental cost effectiveness ratio (ICER) of cost/quality adjusted life year (QALY) for all available INF β products (brands, biosimilars and CBPs) were considered. Both costs and utilities were discounted. Sensitivity analyses were done to assess robustness of model. ICER for Avonex, Rebif and Betaferon was 18712, 11832, 15768 US Dollars ($) respectively when utility attained from literature review has been considered. ICER for available CBPs and biosimilars in Iran was $847, $6964 and $11913. The Markov pharmacoeconomics model determined that according to suggested threshold for developing countries by world health organization, all brand INF β products are cost effective in Iran except Avonex. The best strategy among INF β therapies is CBP intramuscular INF β-1a (Cinnovex). Results showed that a policy of encouraging accessibility to CBPs and biosimilars could make even high technology products cost-effective in LMICs.

  7. Cost-Effectiveness of Different Interferon Beta Products for Relapsing-Remitting and Secondary Progressive Multiple Sclerosis: Decision Analysis Based on Long-Term Clinical Data and Switchable Treatments

    Directory of Open Access Journals (Sweden)

    Shekoufeh Nikfar

    2013-06-01

    Full Text Available Multiple sclerosis (MS is a highly debilitating immune mediated disorder and the second most common cause of neurological disability in young and middle-aged adults. Iran is amongst high MS prevalence countries (50/100,000. Economic burden of MS is a topic of important deliberation in economic evaluations study. Therefore determining of cost-effectiveness interferon beta (INF β and their copied biopharmaceuticals (CBPs and biosimilars products is significant issue for assessment of affordability in Lower-middle-income countries (LMICs.Methods:A literature-based Markov model was developed to assess the cost-effectiveness of three INF βs products compared with placebo for managing a hypothetical cohort of patients diagnosed with relapsing remitting MS (RRMS in Iran from a societal perspective. Health states were based on the Kurtzke Expanded Disability Status Scale (EDSS. Disease progression transition probabilities for symptom management and INF β therapies were obtained from natural history studies and multicenter randomized controlled trials and their long term follow up for RRMS and secondary progressive MS (SPMS. A cross sectional study has been developed to evaluate cost and utility. Transitions among health states occurred in 2-years cycles for fifteen cycles and switching to other therapies was allowed. Calculations of costs and utilities were established by attachment of decision trees to the overall model. The incremental cost effectiveness ratio (ICER of cost/quality adjusted life year (QALY for all available INF β products (brands, biosimilars and CBPs were considered. Both costs and utilities were discounted. Sensitivity analyses were done to assess robustness of model.Results:ICER for Avonex, Rebif and Betaferon was 18712, 11832, 15768 US Dollars ($ respectively when utility attained from literature review has been considered. ICER for available CBPs and biosimilars in Iran was $847, $6964 and $11913.Conclusions:The Markov pharmacoeconomics model determined that according to suggested threshold for developing countries by world health organization, all brand INF β products are cost effective in Iran except Avonex. The best strategy among INF β therapies is CBP intramuscular INF β-1a (Cinnovex. Results showed that a policy of encouraging accessibility to CBPs and biosimilars could make even high technology products cost-effective in LMICs.

  8. Research on Control Strategies of an Open-End Winding Permanent Magnet Synchronous Driving Motor (OW-PMSM-Equipped Dual Inverter with a Switchable Winding Mode for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Liang Chu

    2017-05-01

    Full Text Available An open-end winding permanent magnet synchronous motor (PMSM has a larger range of speed regulation than normal PMSM with the same DC voltage, and the control method is more flexible. It can also manage energy distribution between two power sources without a DC/DC converter. This paper aims at an electric vehicle equipped with OW-PMSM drive system with dual power sources and dual inverters; based on analyzing the external characteristics of each winding mode, we propose a winding mode switching strategy whose torque saturation judgmental algorithm, which is insensitive to motor’s parameters, could automatically realize upswitching of the winding mode. The proposed multi-level current hysteresis modulation algorithm could set the major power source and switch it at any time in independent mode, which accomplishes energy distribution between two power sources; its two control methods, low switching frequency method and high power difference method, could achieve different energy distribution effects. Simulation results confirm the validity and effectiveness of the winding mode switching strategy and current modulation method. They also show that an electric vehicle under the proposed control methods has better efficiency than one equipped with a traditional OW-PMSM drive system under traditional control.

  9. A Bluetooth Low-Energy Transceiver with 3.7-mW All-Digital Transmitter, 2.75-mW High-IF Discrete-Time Receiver, and TX/RX Switchable On-Chip Matching Network

    NARCIS (Netherlands)

    Kuo, F.W.; Binsfeld Ferreira, S.; Chen, R.; Cho, L.C.; Jou, C.P.; Hsueh, F.L.; Madadi, I.; Tohidian, M.; Shahmohammadi, M.; Babaie, M.; Staszewski, R.B.

    2017-01-01

    We present an ultra-low-power Bluetooth low-energy (BLE) transceiver (TRX) for the Internet of Things (IoT) optimized for digital 28-nm CMOS. A transmitter (TX) employs an all-digital phase-locked loop (ADPLL) with a switched current-source digitally controlled oscillator (DCO) featuring low

  10. A microfluidic study of liquid-liquid extraction mediated by carbon dioxide.

    Science.gov (United States)

    Lestari, Gabriella; Salari, Alinaghi; Abolhasani, Milad; Kumacheva, Eugenia

    2016-07-05

    Liquid-liquid extraction is an important separation and purification method; however, it faces a challenge in reducing the energy consumption and the environmental impact of solvent (extractant) recovery. The reversible chemical reactions of switchable solvents (nitrogenous bases) with carbon dioxide (CO2) can be implemented in reactive liquid-liquid extraction to significantly reduce the cost and energy requirements of solvent recovery. The development of new effective switchable solvents reacting with CO2 and the optimization of extraction conditions rely on the ability to evaluate and screen the performance of switchable solvents in extraction processes. We report a microfluidic strategy for time- and labour-efficient studies of CO2-mediated solvent extraction. The platform utilizes a liquid segment containing an aqueous extractant droplet and a droplet of a solution of a switchable solvent in a non-polar liquid, with gaseous CO2 supplied to the segment from both sides. Following the reaction of the switchable solvent with CO2, the solvent becomes hydrophilic and transfers from the non-polar solvent to the aqueous droplet. By monitoring the time-dependent variation in droplet volumes, we determined the efficiency and extraction time for the CO2-mediated extraction of different nitrogenous bases in a broad experimental parameter space. The platform enables a significant reduction in the amount of switchable solvents used in these studies, provides accurate temporal characterization of the liquid-liquid extraction process, and offers the capability of high-throughput screening of switchable solvents.

  11. Development of dose assessment method for high-energy neutrons using intelligent neutron monitor

    International Nuclear Information System (INIS)

    Satoh, Daiki; Sato, Tatsuhiko; Endo, Akira; Yamaguchi, Yasuhiro; Matsufuji, N.; Sato, S.; Takada, M.

    2006-01-01

    Light output of liquid organic scintillator NE213 has been measured for proton, deuteron, triton, 3 He nucleus and alpha particle. A thick graphite target was bombarded with 400-MeV/u C ions to the produce charged particles. Time-of-flight method was adopted to determine the kinetic energy of the charged particles. Light output for proton was also measured using mono-energy beams of 100 and 160 MeV. The experimental results gave a new database of light output. (author)

  12. Laboratory Evaluation of LED T8 Replacement Lamp Products

    Energy Technology Data Exchange (ETDEWEB)

    Richman, Eric E.; Kinzey, Bruce R.; Miller, Naomi J.

    2011-05-23

    A report on a lab setting analysis involving LED lamps intended to directly replace T8 fluorescent lamps (4') showing light output, power, and economic comparisons with other fluorescent options.

  13. Mechanical deformation effect on CsI(Tl) scintillators efficiency

    International Nuclear Information System (INIS)

    Gayshan, V.; Boyarintsev, A.; Gektin, A.; Zosim, D.

    2003-01-01

    Due to the technological limitations in scintillation crystal growth and machining afterwards, crystals always contain certain internal defects and nonuniform distribution of intrinsic stresses. This work is directed to study the effect of CsI(Tl) mechanical deformation on their scintillation efficiency. It is shown that light output changes depend on the type of deformation (shock, steady deformation) and crystallographic orientation of specimen. The value of the phenomenon reaches up to 20% of the CsI(Tl) light output. Stress relaxation is the reason for the scintillator light output recovery. For CsI(Tl) scintillator mechanical deformation effects on light output will significantly decrease in the first 7-10 days after application of the stress and might completely disappear within 30-40 days

  14. CsI(Tl)-photodiode detectors for gamma-ray spectroscopy

    CERN Document Server

    Fioretto, E; Viesti, G; Cinausero, M; Zuin, L; Fabris, D; Lunardon, M; Nebbia, G; Prete, G

    2000-01-01

    We report on the performances of CsI(Tl)-photodiode detectors for gamma-ray spectroscopy applications. Light output yield and energy resolution have been measured for different crystals and read-out configurations.

  15. BSO Crystals for the HHCAL Detector Concept

    International Nuclear Information System (INIS)

    Yang, Fan; Zhang, Liyuan; Zhu, Ren-Yuan; Yuan, Hui

    2015-01-01

    We report an investigation on optical and scintillation properties and radiation hardness of four 20 cm long BSO crystals grown at SIC for the HHCAL detector concept. Their optical and scintillation properties, such as longitudinal transmittance, light output and light response uniformity, were measured before and after γ-ray irradiation. Progresses are observed in optical quality, light output and radiation hardness. Their use for HHCAL concept is discussed

  16. Enhancement of polymer dye lasers by multifunctional photonic crystal lattice

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Xiao, Sanshui; Mortensen, Asger

    2009-01-01

    The light output of dye doped hybrid polymer band-edge lasers is increased more than 100 times by using a rectangular lattice photonic crystal, which provides both feedback and couples more pump light into the laser.......The light output of dye doped hybrid polymer band-edge lasers is increased more than 100 times by using a rectangular lattice photonic crystal, which provides both feedback and couples more pump light into the laser....

  17. Elastic scintillation materials based on polyorganosiloxane

    International Nuclear Information System (INIS)

    Grinev, B.V.; Andryushchenko, L.A.; Shershukov, V.M.; Ulanenko, K.B.; Minakova, R.A.; Sevastjanova, I.V.

    1994-01-01

    The developed elastic scintillators based on polymethyl-phenylsiloxane rubber are characterized by an elevated light output and a low toxicity. The increase of their light output is achieved by raising the content of phenyl chains, varying the chemical structure of luminescent additions and using isopropylnaphthalene. This high-boiling solvent introduced into the scintillation siloxane compositions is confined within siloxane matrix after the hardening of the rubber

  18. Friction Drag Reduction Using Superhydrophobic Surface in High Reynolds Number Turbulent Flow

    Science.gov (United States)

    2017-12-25

    at Princeton using the water channel. SLIPS-coated bodies (prepared according to the instructions provided by Aizenberg) were tested...ASME), 2016 (Smits). 3. Technology Transfer A Switchable Liquid Repellent and Active Fog Harvesting Surface (2016). US Patent Pending

  19. Nanocoatings for Wicking of Low-Viscosity Cryogens Project

    Science.gov (United States)

    Fesmire, James E.

    2014-01-01

    The goal of this project is to develop smart, switchable materials systems for use in thermal management systems, including the evaluation of wicking nanocoatings for use in the transport and storage of cryogens.

  20. Tunable Optical Polymer Systems

    National Research Council Canada - National Science Library

    Jenekhe, S. A; Bard, Allen J; Chen, S. H; Hammond, P. T; Rothberg, L. J

    2004-01-01

    This multidisciplinary university research initiative (MURI) program investigated tunable optical polymer systems suitable for large-area color-switchable coatings and devices, displays, sensors, and other electronic applications...

  1. Nanocoatings for Wicking of Low-Viscosity Cryogens

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to investigate and develop smart, switchable materials systems for use in thermal management systems, including the evaluation of wicking...

  2. Components from wheat roots modify the bioactivity of ZnO and CuO nanoparticles in a soil bacterium

    International Nuclear Information System (INIS)

    Martineau, Nicole; McLean, Joan E.; Dimkpa, Christian O.; Britt, David W.; Anderson, Anne J.

    2014-01-01

    ZnO and CuO nanoparticles (NPs) have widespread commercial uses and their impact on agricultural systems is unresolved. This study examined whether the metabolites washed from wheat (Triticum aestivum L.) roots modulated the metabolic response to the NPs of a biosensor generated in the root colonizer, Pseudomonas putida KT2440. The root wash components boosted light output of the biosensor consistent with their catabolism. Dose-dependent and rapid inhibition of cell metabolism occurred with both ZnO and CuO NPs in water suspensions but high light output was maintained in root wash. Root wash also protected biosensor output in challenges with Zn ions. However the root wash components did not protect culturability or biosensor light output upon exposure to Cu ions. Imaging by atomic force microscopy suggested that root wash materials coated the NPs. We deduced that the response of a microbe to these metal oxide NPs could be negated by components released from roots. - Highlights: • CuO and ZnO nanoparticles cause differential light output from biosensor. • Compounds from roots enhance light output with ZnO nanoparticles and Zn ions. • Toxicity of CuO nanoparticles but not Cu ions could be negated by root metabolites. - The reactivity of nanoparticles with soil bacteria may be modified by components released from plant roots

  3. Energy spectra analysis of the four-layer DOI detector for the brain PET scanner: jPET-D4

    Science.gov (United States)

    Yoshida, Eiji; Kitamura, Keishi; Tsuda, Tomoaki; Shibuya, Kengo; Yamaya, Taiga; Inadama, Naoko; Hasegawa, Tomoyuki; Murayama, Hideo

    2006-02-01

    A depth of interaction (DOI) detector is being developed for the brain PET scanner, jPET-D4. We introduce a light output correction procedure to compensate for variations among the crystal elements in the DOI detector. Under uniform irradiation with 511 keV gamma rays, we estimate the light output of each crystal element by identifying each crystal element, and generate a look-up table (LUT) for light output correction. We evaluate the energy resolution of all crystal elements. The energy resolution of 16% is achieved after light output correction for all crystal elements. The DOI detector can correct light output variations that are related to the DOI. We analyze the crystal position dependence of the energy spectra due to inter-crystal scattering among the multiple crystal elements in the DOI detector. It is highly possible that gamma rays interacting with central crystal elements in the crystal array are absorbed by surrounding crystal elements and the Compton part of the energy spectrum is decreased. Inter-crystal scattering has less impact on the energy resolution of the DOI detector.

  4. Development of efficient, radiation-insensitive GaAs:Zn LEDs

    International Nuclear Information System (INIS)

    Barnes, C.E.

    1977-01-01

    Although amphoterically Si doped GaAs LEDs are commercially popular because of their high light output, they are extremely sensitive to irradiation. Therefore, it would be desirable to have a viable alternative available for radiation environment applications. In this work it is shown that by increasing the hole concentration in the active region of nonamphoterically doped GaAs LEDs, one can simultaneously achieve high light output and low radiation sensitivity. Experimental results indicate that the minority carrier lifetime is smaller in more heavily doped devices so that the lifetime-damage constant, tau/sub o/K, is also smaller. Hence, the heavily doped devices should have greater radiation hardness. Neutron-induced light output degradation data as a function of hole concentration confirm this conclusion. The results also show that the pre-irradiation light output is greatest in the heavily doped LEDs. The accompanying decrease of tau/sub o/ in the heavily doped devices indicates that the total minority carrier lifetime is at least partially controlled by the radiative lifetime; a requirement for simultaneously achieving radiation hardness and high initial light output. Finally, an experimental comparison with amphoterically Si doped LEDs shows that the heavily doped devices are superior for neutron fluences greater than 2 x 10 12 n/cm 2

  5. New, dense, and fast scintillators based on rare-earth tantalo-niobates

    International Nuclear Information System (INIS)

    Voloshyna, O.V.; Boiaryntseva, I.A.; Baumer, V.N.; Ivanov, A.I.; Korjik, M.V.; Sidletskiy, O.Ts.

    2014-01-01

    Samples of undoped yttrium and gadolinium tantalo-niobates with common formulae RE(Nb x Ta 1−x )O 4 , where RE=Y or Gd and x=0–1, have been obtained by solid-state reaction. Systematic study of structural, luminescent, and scintillation properties of these compounds was carried out. Lattice parameters and space groups of the mixed compounds were identified. UV- and X-ray luminescence spectra, as well as relative light outputs and scintillation decay times are measured. Gadolinium tantalo-niobate with the formulae GdNb 0.2 Ta 0.8 O 4 showed the light output around 13 times larger than PbWO 4 and fast decay with time constant 12 ns without additional slow component. Gadolinium tantalo-niobates may be considered as promising materials for high energy physics due to extremely high density, substantial light output, and fast decay. -- Highlights: •Structural, optical and scintillation properties of the rare earth tantalo-niobates were studied. •Light output shows about gradual increase with Nb content in GdTa x Nb 1−x O 4 . •Light output increases by 2–7 times relatively to yttrium tantalate and niobate in YTa x Nb 1−x O 4 . •GdTa 0.8 Nb 0.2 O 4 demonstrates the most promising scintillation parameters

  6. Holographic Polymer-Dispersed Liquid Crystals: Materials, Formation, and Applications

    Directory of Open Access Journals (Sweden)

    Y. J. Liu

    2008-01-01

    Full Text Available By combining polymer-dispersed liquid crystal (PDLC and holography, holographic PDLC (H-PDLC has emerged as a new composite material for switchable or tunable optical devices. Generally, H-PDLC structures are created in a liquid crystal cell filled with polymer-dispersed liquid crystal materials by recording the interference pattern generated by two or more coherent laser beams which is a fast and single-step fabrication. With a relatively ideal phase separation between liquid crystals and polymers, periodic refractive index profile is formed in the cell and thus light can be diffracted. Under a suitable electric field, the light diffraction behavior disappears due to the index matching between liquid crystals and polymers. H-PDLCs show a fast switching time due to the small size of the liquid crystal droplets. So far, H-PDLCs have been applied in many promising applications in photonics, such as flat panel displays, switchable gratings, switchable lasers, switchable microlenses, and switchable photonic crystals. In this paper, we review the current state-of-the-art of H-PDLCs including the materials used to date, the grating formation dynamics and simulations, the optimization of electro-optical properties, the photonic applications, and the issues existed in H-PDLCs.

  7. Size dependence of silica nanospheres embedded in 385 nm ultraviolet light-emitting diodes on a far-field emission pattern.

    Science.gov (United States)

    Park, Young Jae; Han, Nam; Ryu, Beo Deul; Han, Min; Ko, Kang Bok; Cuong, Tran Viet; Cho, Jaehee; Suh, Eun-Kyung; Hong, Chang-Hee

    2014-10-20

    We demonstrate that the use of silica nanospheres (SNs) with sizes close to the emission wavelength of light-emitting diodes (LEDs) can enhance the light output power and manipulate the far-field emission pattern. Near-ultraviolet (NUV)-LEDs grown on a patterned sapphire substrate embedded with 300 nm SNs show a three times higher light output power than that without SNs, when measured through the top side. For far-field emission measurements, the LEDs embedded with 300 nm SNs show the significant increase of front emission due to the improved crystal quality of epitaxial films as well as the increase of Mie scattering effect of SNs. These experimental results indicate the important role of the size of embedded SNs in enhancing the light output power for NUV-LEDs.

  8. Comparison of analog and digital pulse-shape-discrimination systems

    Energy Technology Data Exchange (ETDEWEB)

    Sosa, C.S., E-mail: cssosa@umich.edu; Flaska, M.; Pozzi, S.A.

    2016-08-01

    Pulse shape discrimination (PSD) performance of two optimized PSD systems (one digital and one analog) is compared in this work. One system uses digital charge integration, while the other system uses analog zero crossing. Measurements were conducted with each PSD system using the CAEN V1720 (250 MHz) data acquisition system. An organic-liquid scintillator, coupled to a photo-multiplier tube, was used to detect neutrons and gamma rays from a Cf-252 spontaneous-fission source. The PSD performance of both systems was optimized and quantified using a traditional figure-of-merit (FOM) approach. FOM's were found for three, 300 keVee light-output bins, spanning from 100 to 1000 keVee, and one larger bin from 100 to 1800 keVee. Digital PSD outperformed analog PSD in the lowest light-output bin by approximately 50%, and by 11% for the highest light-output bin.

  9. An Electronically Controlled 8-Element Switched Beam Planar Array

    KAUST Repository

    Sharawi, Mohammad S.

    2015-02-24

    An 8-element planar antenna array with electronically controlled switchable-beam pattern is proposed. The planar antenna array consists of patch elements and operates in the 2.45 GHz ISM band. The array is integrated with a digitally controlled feed network that provides the required phases to generate 8 fixed beams covering most of the upper hemisphere of the array. Unlike typical switchable beam antenna arrays, which operate only in one plane, the proposed design is the first to provide full 3D switchable beams with simple control. Only a 3-bit digital word is required for the generation of the 8 different beams. The integrated array is designed on a 3-layer PCB on a Taconic substrate (RF60A). The total dimensions of the fabricated array are 187.1 × 261.3 × 1.3mm3.

  10. Energy resolution and light yield non-proportionality of ZnSe Te scintillator studied by large area avalanche photodiodes and photomultipliers

    CERN Document Server

    Balcerzyk, M; Moszynski, M; Kapusta, M; Szawlowski, M

    2002-01-01

    The ZnSe : Te scintillator has been studied by means of a photomultiplier with an extended bialkali photocathode, a large area avalanche photodiode (LAAPD) and a PIN photodiode. The light output was determined to be 28 300+-1700 photons/MeV. Results indicate good proportionality for light output versus gamma-ray energy. Measurements of the 662 keV gamma-ray energy spectrum recorded using a LAAPD resulted in an energy resolution of 5.4+-0.3%. Based on these results, an intrinsic energy resolution of 3.3+-0.7% has been calculated.

  11. III-V/SOI vertical cavity laser structure for 120 Gbit/s speed

    DEFF Research Database (Denmark)

    Park, Gyeong Cheol; Xue, Weiqi; Mørk, Jesper

    2015-01-01

    Ultrashort-cavity structure for III-V/SOI vertical cavity laser with light output into a Si waveguide is proposed, enabling 17 fJ/bit efficiency or 120 Gbit/s speed. Experimentally, 27-GHz bandwidth is demonstrated at 3.5 times of threshold. © 2015 OSA.......Ultrashort-cavity structure for III-V/SOI vertical cavity laser with light output into a Si waveguide is proposed, enabling 17 fJ/bit efficiency or 120 Gbit/s speed. Experimentally, 27-GHz bandwidth is demonstrated at 3.5 times of threshold. © 2015 OSA....

  12. Study of a pure CsI crystal readout by APD for Belle II end cap ECL upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Y., E-mail: jin@hep.phys.s.u-tokyo.ac.jp [Department of Physics, the University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 (Japan); Aihara, H. [Department of Physics, the University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 (Japan); Borshchev, O.V. [Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393 (Russian Federation); Epifanov, D.A. [Department of Physics, the University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 (Japan); Ponomarenko, S.A.; Surin, N.M. [Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393 (Russian Federation)

    2016-07-11

    A scintillation counter consisting of a pure CsI crystal and avalanche photodiodes (Hamamatsu APD S8664-55 and S8664-1010) has been studied for the upgrade of the end cap electromagnetic calorimeter of Belle II detector. An essential increase of the light output was achieved with wavelength shifters based on nanostructured organosilicon luminophores. - Highlights: • A scintillation counter consisting of a pure CsI crystal and avalanche photodiodes has been studied. • The equivalent noise charge and equivalent noise energy of the counter have been measured. • An essential increase of the light output was achieved with wavelength shifters.

  13. Fiber optic spectroscopic digital imaging sensor and method for flame properties monitoring

    Science.gov (United States)

    Zelepouga, Serguei A [Hoffman Estates, IL; Rue, David M [Chicago, IL; Saveliev, Alexei V [Chicago, IL

    2011-03-15

    A system for real-time monitoring of flame properties in combustors and gasifiers which includes an imaging fiber optic bundle having a light receiving end and a light output end and a spectroscopic imaging system operably connected with the light output end of the imaging fiber optic bundle. Focusing of the light received by the light receiving end of the imaging fiber optic bundle by a wall disposed between the light receiving end of the fiber optic bundle and a light source, which wall forms a pinhole opening aligned with the light receiving end.

  14. Investigation of Optical and Electrical Properties of Wide Band Gap Materials

    Science.gov (United States)

    1976-06-01

    were formed. The high melting point of CuGaS2 also led to difficulties. By using a fast start up employing rapid heating to 1050 °C where the temperature...rates and selecting diffusing impurities mainly because of fast diffusion rates at lower temperatures 400-600 0C. This is possibly true for all I-III-VI2...observed any case where the sandwich structure gave clearly better light output. For hgh resistance phosphors, no light output is observed sometimes

  15. Two state coercivity driven by phase coexistence in vanadium sesquioxide/nickel bulk hybrid material

    Science.gov (United States)

    Urban, C.; Quesada, A.; Saerbeck, T.; Garcia, M. A.; de la Rubia, M. A.; Valmianski, I.; Fernández, J. F.; Schuller, I. K.

    2016-09-01

    We developed a bulk hybrid material consisting of a vanadium sesquioxide (V2O3) matrix with nickel (Ni) rich inclusions that exhibit a switchable two-state magnetic coercivity. The V2O3 matrix magnetoelastically couples with the Ni-rich inclusions and its structural phase transition causes two possible magnetic coercivity states. Differences of up to 13% in the temperature window of 14 K are observed, depending whether the transition occurs from rhombohedral to monoclinic or vice versa. These findings provide a pathway for the development of bulk switchable coercivity materials. We present routes to further enhance the magnetoelastic effect by increasing the oxide/ferromagnetic material coupling.

  16. 16 CFR 305.5 - Determinations of estimated annual energy consumption, estimated annual operating cost, and...

    Science.gov (United States)

    2010-01-01

    ...) Refrigerators and refrigerator-freezers—§ 430.23(a). (2) Freezers—§ 430.23(b). (3) Dishwashers—§ 430.23(c). (4... representation of the design voltage, wattage, light output or life of such lamp or for any representation made...

  17. 78 FR 48769 - Mercedes-Benz USA, LLC and Daimler AG, Receipt of Petition for Decision of Inconsequential...

    Science.gov (United States)

    2013-08-09

    ...-2251. Comments must be written in the English language, and be no greater than 15 pages in length... production variations on light output. In order to provide a complete overview of the brightness of the... production variations in low beam lights, in many cases, there will be no exceedance of the combined parking...

  18. Scintillator based on SiO2-aerogel

    International Nuclear Information System (INIS)

    Boyko, I.R.; Ignatenko, M.A.; Esenak, K.; Kuhta, L.; Ruzicka, J.; Fainor, V.

    1995-01-01

    For increasing the light output of SiO 2 -aerogel two aerogel samples were doped with the wavelength shifter POPOP. As a result a scintillator with intermediate density between the gas and the solid state has been produced. The light pulse shapes of the both samples are well approximated by a sum of two exponents with the decay times 1.4±0.1 ns (58% of total light output) and 5.2±0.4 ns (42%). Under irradiation of 5.5 MeV α-particles the light output of the sample with smaller wavelength shifter concentration was 30% and that of the sample with larger concentration was 8% of the light output of a plastic scintillator (polysterene, 2% paraterphenil, 0.2% POPOP). The obtained data indicate that the α/β ratio for both samples is close to 1. This material can be used in experiments where the amount of substance in the way of particles to be detected is a critical factor. (orig.)

  19. Advanced LED package with temperature sensors and microfluidic cooling

    NARCIS (Netherlands)

    Ye, H.; Zeijl, H. van; Sokolovskij, R.; Gielen, A.W.J.; Zhang, G.Q.

    2013-01-01

    Light-emitting diodes (LEDs) are revolutionizing the illumination with energy savings and enhanced functionality. However, around 80% of the input power will be still transferred to heat. As the elevated temperature negatively affects the maximum light output, efficiency, quality, reliability and

  20. Selecting an LCD Projector for Your School.

    Science.gov (United States)

    Media & Methods, 1999

    1999-01-01

    Presents criteria for schools selecting LCD (liquid crystal display) projectors based on expert opinions from the International Communications Industries Association, Inc. (ICIA). Highlights include intended use of the equipment; light output; portability; formats; video outputs; price; resolution; DLP technology; and a list of LCD projector…

  1. Hollow-Core Fiber Lamp

    Science.gov (United States)

    Yi, Lin (Inventor); Tjoelker, Robert L. (Inventor); Burt, Eric A. (Inventor); Huang, Shouhua (Inventor)

    2016-01-01

    Hollow-core capillary discharge lamps on the millimeter or sub-millimeter scale are provided. The hollow-core capillary discharge lamps achieve an increased light intensity ratio between 194 millimeters (useful) and 254 millimeters (useless) light than conventional lamps. The capillary discharge lamps may include a cone to increase light output. Hollow-core photonic crystal fiber (HCPCF) may also be used.

  2. Influence of light and temperature on flower development in gerbera

    NARCIS (Netherlands)

    Dueck, T.A.; Kempkes, F.L.K.; Helm, Van Der F.; Groot, De M.

    2017-01-01

    Higher intensities artificial lighting are currently being installed for gerbera crops, mainly because of the relatively low costs of high-capacity HPS lamps with a higher light output. In addition, LED lighting systems are becoming even more efficient. In order to gain insight on increasing

  3. Recent results on radiation hardness tests of WLS fibers for the ATLAS Tilecal hadronic calorimeter

    CERN Document Server

    Varanda, M J; Gómez, A; Maio, A

    2000-01-01

    Three types of fibers, that were candidates to be used in the Tilecal /ATLAS detector were irradiated in a /sup 60/Co gamma source. The degradation of the light output and attenuation length were measured a few hours and several days after the end of the irradiation. The results are presented. (6 refs).

  4. Aging characteristics of blue InGaN micro-light emitting diodes at an extremely high current density of 3.5 kA cm−2

    International Nuclear Information System (INIS)

    Tian, Pengfei; Liu, Ran; Althumali, Ahmad; Gu, Erdan; Watson, Ian M; Dawson, Martin D

    2016-01-01

    The aging characteristics of blue InGaN micro-light emitting diodes (micro-LEDs) with different sizes have been studied at an extremely high current density 3.5 kA cm −2 for emerging micro-LED applications including visible light communication (VLC), micro-LED pumped organic lasers and optogenetics. The light output power of micro-LEDs first increases and then decreases due to the competition of Mg activation in p-GaN layer and defect generation in the active region. The smaller micro-LEDs show less light output power degradation compared with larger micro-LEDs, which is attributed to the lower junction temperature of smaller micro-LEDs. It is found that the high current density without additional junction temperature cannot induce significant micro-LED degradation at room temperature but the combination of the high current density and high junction temperature leads to strong degradation. Furthermore, the cluster LEDs, composed of a micro-LED array, have been developed with both high light output power and less light output degradation for micro-LED applications in solid state lighting and VLC. (paper)

  5. Scintillator quenching effects observed in the AMS-1 TOF data

    International Nuclear Information System (INIS)

    Esquivel, O.; Reyes, T.; Menchaca-Rocha, A.

    2001-01-01

    An analytical expression for the light output response of plastic scintillators as a function of the energy and the z identity of the incident ion is proposed. The effect of the δ rays is considered in the calculation of the scintillation efficiency

  6. How to quench light attenuation in plastic scintillators

    CERN Document Server

    Gabriele, S A; Massam, Thomas; Zichichi, A

    1972-01-01

    The problem of light attenuation in plastic scintillators is well known and has existed since their invention. The authors show how the problem has been investigated and overcome via a study of the effect of the chemical concentration of the scintillator components on the light output pattern. (1 refs).

  7. Scintillator quenching effects observed in the AMS-1 TOF data

    Science.gov (United States)

    Esquivel, O.; Reyes, T.; Menchaca-Rocha, A.

    2001-05-01

    An analytical expression for the light output response of plastic scintillators as a function of the energy and the z identity of the incident ion is proposed. The effect of the δ rays is considered in the calculation of the scintillation efficiency. .

  8. The chemistry of two-component fluoride crystalline optical media for heavy, fast, radiation hard scintillators

    International Nuclear Information System (INIS)

    Sobolev, B.P.; Krivandina, E.A.; Fedorov, P.P.; Vasilchenko, V.G.

    1994-01-01

    Prospects for preparation of two-component dense optical materials for scintillators are shown, using data on phase diagrams of about 300 MF m - RF n (m, n ≤ 4) type systems, formed by metal fluorides. Primary characteristics (decay time and light output of luminescence, radiation hardness, etc.) of some multicomponent crystals are reported

  9. 77 FR 21038 - Energy Conservation Program: Test Procedures for Light-Emitting Diode Lamps

    Science.gov (United States)

    2012-04-09

    ... from zero to 1,000 hours of operation does not significantly affect light output or lifetime ratings... to the initial lumen output (at zero hours) in less than 1,000 hours and others that may take longer... the energy used by annual operating hours and an estimate for energy cost per kilowatt- hour. FTC...

  10. CALiPER Application Summary Report 22: LED MR16 Lamps

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2014-09-01

    An initial sample of 27 LED MR16 lamps and 8 halogen benchmarks underwent photometric testing according to IES LM-79-08. CALiPER Application Summary Report 22 focuses on the initial performance based on light output, efficacy, distribution, color quality, electrical characteristics, and form factor, with comparisons to the benchmarks and ENERGY STAR qualification thresholds.

  11. Scintillation Properties of Praseodymium Activated Lu3Al5O12 Single Crystals

    NARCIS (Netherlands)

    Drozdowski, W.; Dorenbos, P.; De Haas, J.T.M.; Drozdowska, R.; Owens, A.; Kamada, K.; Tsutsumi, K.; Usuki, Y.; Yanagida, T.; Yoshikawa, A.

    2008-01-01

    Scintillation properties of LuAG:Pr grown by Furukawa Co. Ltd., Japan, have been studied. The best crystals display light outputs up to 19000 ph/MeV and an energy resolution of 4.6% at 662 keV. The scintillation yield is found to be a function of size and temperature of the sample; it can be

  12. Temperature quenching in LAB based liquid scintillator

    Science.gov (United States)

    Sörensen, A.; Hans, S.; Junghans, A. R.; Krosigk, B. v.; Kögler, T.; Lozza, V.; Wagner, A.; Yeh, M.; Zuber, K.

    2018-01-01

    The effect of temperature changes on the light output of LAB based liquid scintillator is investigated in a range from -5 to 30°C with α -particles and electrons in a small scale setup. Two PMTs observe the scintillator liquid inside a cylindrically shaped aluminum cuvette that is heated or cooled and the temperature dependent PMT sensitivity is monitored and corrected. The α -emitting isotopes in dissolved radon gas and in natural Samarium (bound to a LAB solution) excite the liquid scintillator mixtures and changes in light output with temperature variation are observed by fitting light output spectra. Furthermore, also changes in light output by compton electrons, which are generated from external calibration γ -ray sources, is analysed with varying temperature. Assuming a linear behaviour, a combined negative temperature coefficient of {(-0.29 ± 0.01)}{ %/°}C is found. Considering hints for a particle type dependency, electrons show {(-0.17 ± 0.02)}{ %/°}C, whereas the temperature dependency seems stronger for α -particles, with {(-0.35 ± 0.03)}{ %/°}C. Due to a high sampling rate, a pulse shape analysis can be performed and shows an enhanced slow decay component at lower temperatures, pointing to reduced non-radiative triplet state de-excitations.

  13. A technical study of TLD beta calibration factor for exposures to depleted uranium

    International Nuclear Information System (INIS)

    Ashley, J.C.; Turner, J.E.; McMahan, K.L.; Souleyrette, M.L.; Bogard, R.S.

    1995-06-01

    The beta calibration factor for converting light output (on reading a thermoluminescent dosimeter) to shallow dose equivalent has been reexamined through theoretical calculations and experimental measurements. The results support the previously determined value for contact with a depleted uranium slab but indicate that for many actual workplace situations, the contact value may be overly conservative

  14. 76 FR 53648 - Federal Motor Vehicle Safety Standards: Occupant Crash Protection

    Science.gov (United States)

    2011-08-29

    ... and any right- front DSP equipped with an automatic belt.\\1\\ The means provided to lock the lap belt... assembly as compared to an automatic locking retractor (ALR). An ALR is a seat belt retractor that locks... requirements, vehicle manufacturers commonly use a switchable seat belt retractor (ELR/ automatic locking...

  15. Robust Fallback Scheme for the Danish Automatic Voltage Control System

    DEFF Research Database (Denmark)

    Qin, Nan; Dmitrova, Evgenia; Lund, Torsten

    2015-01-01

    This paper proposes a fallback scheme for the Danish automatic voltage control system. It will be activated in case of the local station loses telecommunication to the control center and/or the local station voltage violates the acceptable operational limits. It cuts in/out switchable and tap...

  16. Cationic AuIII versus AuI : Catalyst-Controlled Divergent Reactivity of Alkyne-Tethered Lactams.

    Science.gov (United States)

    Alcaide, Benito; Almendros, Pedro; Cembellín, Sara; Fernández, Israel; Martínez Del Campo, Teresa

    2017-03-02

    Switchable reactivity through cationic gold-based catalyst control built on the oxidation state, namely cationic Au III versus Au I , has been achieved in the direct functionalization of 2-azetidinone-tethered alkynyl indoles. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. 76 FR 37795 - Notice of Availability of Government-Owned Inventions; Available for Licensing

    Science.gov (United States)

    2011-06-28

    ... Smoke Detector//U.S. Patent No. 7,307,702: Color Switchable Stress-Fracture Sensor for Damage Control//U...,707,957: Structural Support to Underwater Vessels Using Shape Memory Alloys//U.S. Patent No. 7,714,536...

  18. Electrochemical and SEM properties of Co ion in hexagonal ...

    Indian Academy of Sciences (India)

    Administrator

    switchable privacy windows, optical computing and opti- cal devices for communication networks (Zhang and. Schuster 1994; Deschenaux et al 1996). The hexagonal phase composition of the P84/Co/p-xylene system was determined according to the phase diagram established in the literature (Raman et al 1996; Paavola ...

  19. Spectroscopic investigation of the far-infrared properties of liquid crystals

    DEFF Research Database (Denmark)

    Reuter, M.; Vieweg, N.; Fischer, B. M.

    2013-01-01

    Liquid crystals are one of the most promising base materials for switchable devices at THz frequencies. Therefore, a precise understanding of the optical parameters is crucial. Here, we present the refractive indices and absorption coefficients for 5 CB and an isothiocyanate terminated liquid...

  20. "IMPROVED REAL-POWER LOSS MINIMISATION"

    African Journals Online (AJOL)

    user

    1985-09-01

    Sep 1, 1985 ... power system losses by controlling the switchable reactive power sources, generator terminal voltages ... is static because a system design is required for a given set of conditions. ... (iii) transformer tap ratios: (1.0±0.05)tij. (iv) reactive power injections: maximum of MVAr (capacitive) and 24 MVAr. (reactive).

  1. Hydrogen-induced electrical and optical switching in Pd capped Pr ...

    Indian Academy of Sciences (India)

    Wintec

    Abstract. In this study, modification in the properties of hydrogen-induced switchable mirror based on Pr nanoparticle layers is reported. The reversible changes in hydrogen-induced electrical and optical properties of Pd capped Pr nanoparticle layers have been studied as a function of hydrogenation time and compared.

  2. IR spectroscopy on jet-cooled isolated two-station rotaxanes

    NARCIS (Netherlands)

    Rijs, A.M.; Kay, E.R.; Leigh, D.A.; Buma, W.J.

    2011-01-01

    High-resolution IR spectroscopy has been employed to study isolated, switchable [2]rotaxanes. IR absorption spectra of two-station rotaxanes, their separate thread, and macrocycle components, as well as those of the individual stations incorporated into the thread, have been measured in the

  3. Tunable coupling and ultrastrong interaction in circuit quantum electrodynamics

    International Nuclear Information System (INIS)

    Baust, Alexander Theodor

    2015-01-01

    For future quantum information and quantum simulation architectures with superconducting circuits, a profound understanding of the coupling mechanisms between the individual building blocks is essential. In our work, we investigate galvanically coupled qubit-resonator systems, demonstrate the phenomenon of ultrastrong coupling and realize qubit mediated tunable and switchable coupling between two frequency-degenerate coplanar microwave resonators.

  4. First synthesis and electronic properties of diphenothiazine dumbbells bridged by heterocycles.

    Science.gov (United States)

    Franz, Adam W; Popa, Larisa N; Rominger, Frank; Müller, Thomas J J

    2009-02-07

    According to cyclic voltammetry, symmetrical dumbbell-shaped phenothiazine dyads bridged by heterocycles show intense electronic coupling between the redox-active phenothiazine moieties. Furthermore, the fluorescence of the pyridyl-bridged derivatives can be controlled by pH change giving reversibly switchable redox-active biselectrophore dyads.

  5. Switching and tuning organic solid state luminescence via a supramolecular approach

    OpenAIRE

    DRAPER, SYLVIA MARY; VARGHESE, SREEJA

    2009-01-01

    PUBLISHED Unusual intermolecular interactions of organic luminescent acid, 2-cyano-3(4-(diphenylamino)phenyl)acrylic acid (CDPA), with amines lead to the formation of supramolecular luminescence systems with switchable and tunable solid-state luminescence This material is based upon works supported by EU FP6 [MKTD-CT-2004-014472] and Science Foundation Ireland [05PICAI819

  6. Multifunctional switches based on bis-imidazole derivative

    Indian Academy of Sciences (India)

    Administrator

    stimuli and generate readable outputs such as elec- tronic or optical signals those reflect the molecular states. In this paper, we report a single molecule which is capable of integrating the effects of multiple stimuli and producing three switchable ... trometer using TMS as internal standard. UV-Vis spectra were recorded on a ...

  7. Automatisch snelheidstoezicht op de N266 in Noord-Brabant : evaluatie van het effect op lange termijn.

    NARCIS (Netherlands)

    Oei, H.-l. Minnen, J. van & Goldenbeld, C.

    1995-01-01

    Four road stretches having a speed limit of 80 km/h were equipped with an electronic speed management system, consisting of a fixed warning sign, a switchable sign only showing when cars were speeding and automatic speed enforcing using radar and camera from road side mounted posts. This system was

  8. Electrochromic devices and related products and methods

    Energy Technology Data Exchange (ETDEWEB)

    Snow, Timothy; McFadden, Judith; Tenent, Robert

    2018-01-30

    An electrochromic device may be switchable between a transparent state and at least one reflective state. A lithium-containing reflective feature may form when the electrochromic device is switched from the transparent state to the reflective state. Various products and methods may involve the electrochromic device.

  9. Download this PDF file

    African Journals Online (AJOL)

    AJTCAM

    Water decoction made from the seed of Hunteria umbellata is widely used in the traditional management of diabetes mellitus by ... ACTH – adrenocorticotropic hormone; ASW – automatic switchable; CHCl3 – chloroform; 12CNMR – carbon nuclear magnetic resonance; DCM .... detecting (Draggendorff's) reagents. The ethyl ...

  10. Electrical pulse burnout testing of light-emitting diodes

    International Nuclear Information System (INIS)

    Kalma, A.H.; Fischer, C.J.

    1975-01-01

    Electrical pulse burnout thresholds were measured in GaAs, GaAsP, and GaP light-emitting diodes (LEDs) by studying the degradation in light output and the change in I-V characteristics both during the pulse and in the steady state. Pulse widths ranging from a few hundred nsec to 100 μsec were used. Light output degradation was the most sensitive parameter and was used to determine the thresholds. Just above threshold, damage is caused by an increase in generation-recombination current in the space-charge retion. This current is non-radiative and the light output drops, but the damage is not catastrophic. At higher power, the junction burns through and shunt resistance paths are formed which more drastically degrade the light output. The experimental data match reasonably with the theoretical Wunsch--Bell/Tasca model if a burnout area of 1 / 10 the junction area is assumed. Both the adiabatic term (At -1 ) and the heat flow term (Bt - /sup 1 / 2 /) contribute in all devices, and the equilibrium term (C) contributes in some GaAsP devices. The scatter in the data for GaAs devices is greater than that for GaAsP devices, apparently because the former types have a significant fraction of mavericks with lower-than-normal thresholds. The use of LEDs to examine electrical pulse burnout is advantageous because the light output is quite sensitive to damage and the combined measurement of optical and electrical properties provides additional information about the mechanisms involved

  11. Effects of agriculture on wood breakdown and microbial biofilm respiration in southern Appalachian streams

    Science.gov (United States)

    M.E. McTammany; E.F. Benfield; J.R. Webster

    2008-01-01

    Agriculture causes high sediment, nutrient and light input to streams, which may affect rates of ecosystem processes, such as organic matter decay. In the southern Appalachians, socioeconomic trends over the past 50 years have caused widespread abandonment of farmland with subsequent reforestation. Physical and chemical properties of streams in these...

  12. Circadian Clocks : Running on Redox

    NARCIS (Netherlands)

    Merrow, Martha; Roenneberg, Till

    2001-01-01

    The circadian clock in all organisms is so intimately linked to light reception that it appears as if evolution has simply wired a timer into the mechanism that processes photic information. Several recent studies have provided new insights into the role of light input pathways in the circadian

  13. Bacterial community structure in High-Arctic snow and freshwater as revealed by pyrosequencing of 16S rRNA genes and cultivation

    DEFF Research Database (Denmark)

    Møller, Annette; Søborg, Ditte Andreasen; Al-Soud, Waleed Abu

    2013-01-01

    controlled the distribution of the Cyanobacteria and algae in the snow while carbon and nitrogen fixed by these autotrophs in turn fed the heterotrophic bacteria. In the lake, a probable lower light input relative to snow resulted in low numbers of Cyanobacteria and chloroplasts and, hence, limited input...

  14. Improving current spreading of GaN-based LEDs by N-pad current surrounding design

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Chun-Fu [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, No. 1 University Road, Tainan City (China); Su, Yan-Kuin [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, No. 1 University Road, Tainan City (China); Department of Electrical Engineering, Kun-Shan University, Yung-Kang City, Tainan County 710 (China); Lin, Chun-Liang [Department of Electronic Engineering, Kun-Shan University, Yung-Kang City, Tainan County 710 (China)

    2010-07-15

    In this report, the motivation of why we attempt to design current spreading, or current surrounding, is try to provide other current paths, expect to improve the current spreading of LEDs and get lower forward voltage at the same time. Attempt to avoid the trade-off between p -electrode area for uniform current spreading and emitting area for light output of LEDs. Compared to reference LEDs, we can find that the light output intensity of chips with n -pad current surrounding design will decay at higher current injection. This can be attributed to the metal on pitch we design, with better current spreading and much metal area connected to n -pad, so less current crowding effect and less heat-accumulation in chips (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Direct periodic patterning of GaN-based light-emitting diodes by three-beam interference laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeomoh; Ji, Mi-Hee; Detchprohm, Theeradetch [Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); Yuan, Dajun; Guo, Rui [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); Liu, Jianping [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215125 (China); Asadirad, Mojtaba [Materials Engineering Program, University of Houston, Houston, Texas 77204-4005 (United States); Kwon, Min-Ki [Department of Photonic Engineering, Chosun University, Seosuk-dong, Gwangju 501-759 (Korea, Republic of); Dupuis, Russell D. [Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Das, Suman [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Ryou, Jae-Hyun, E-mail: jryou@uh.edu [Materials Engineering Program, University of Houston, Houston, Texas 77204-4005 (United States); Department of Mechanical Engineering and Texas Center for Superconductivity at the University of Houston (TcSUH), University of Houston, Houston, Texas 77204-4006 (United States)

    2014-04-07

    We report on the direct patterning of two-dimensional periodic structures in GaN-based light-emitting diodes (LEDs) through laser interference ablation for the fast and reliable fabrication of periodic micro- and nano-structures aimed at enhancing light output. Holes arranged in a two-dimensional hexagonal lattice array having an opening size of 500 nm, depth of 50 nm, and a periodicity of 1 μm were directly formed by three-beam laser interference without photolithography or electron-beam lithography processes. The laser-patterned LEDs exhibit an enhancement in light output power of 20% compared to conventional LEDs having a flat top surface without degradation of electrical and optical properties of the top p-GaN layer and the active region, respectively.

  16. Enhanced light-extraction in GaInN near-ultraviolet light-emitting diode with Al-based omnidirectional reflector having NiZn /Ag microcontacts

    Science.gov (United States)

    Kim, Jong Kyu; Xi, J.-Q.; Luo, Hong; Fred Schubert, E.; Cho, Jaehee; Sone, Cheolsoo; Park, Yongjo

    2006-10-01

    Enhancement of light extraction in a GaInN near-ultraviolet light-emitting diode (LED) employing an Al-based omnidirectional reflector (ODR) consisting of GaN, a SiO2 low-refractive-index layer perforated by an array of NiZn /Ag microcontacts, and an Al layer is presented. A theoretical calculation reveals that a SiO2/Al ODR has much higher reflectivity than both a SiO2/Ag ODR and a Ag reflector at a wavelength of 400nm. It is experimentally shown that GaInN near-ultraviolet LEDs with GaN /SiO2/Al ODR have 16% and 38% higher light output than LEDs with SiO2/Ag ODR and Ag reflector, respectively. The higher light output is attributed to enhanced reflectivity of the Al-based ODR in the near-ultraviolet wavelength range.

  17. Controversial bulb disks still marketed as energy savers

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, W.

    1982-05-24

    Despite a 1980 DOE study showing that incandescent bulb disks decrease lamp efficiency by reducing light output as well as energy consumption, at least two manufacturers are still marketing the disks. The companies claim that the Power Disc and Lite-Saver will extend bulb life up to 100 times and reduce wattage 42%, although they both acknowledge that light output is reduced as much as 74% for a 53% efficiency drop. Some users claim the life-extension feature is important when bulb replacement is difficult. The DOE study concludes that the disks are not cost-effective if the user wants equivalent lighting, and questions some of the manufacturers' advertising claims. Satisfied users counter with reports of good performance and no problems with shock or other safety hazards. (DCK)

  18. Energy response and reaction losses in plastic scintillators

    International Nuclear Information System (INIS)

    Papandreou, Z.; Lolos, G.J.; Huber, G.M.; Cormier, J.C.; Naqvi, S.I.H.; Mathie, E.L.; Jones, G.; Trelle, R.P.; Alanoglu, X.; Orfanakos, S.

    1987-12-01

    The energy dependence of the scintillation response (light output) of plastic scintillator BC400 has been investigated for protons in the energy region of 60 to 220 MeV. In this region the scintillation exhibits a linear response, as well as a noticeable difference in the light output between stopping and passing-through (transmission) protons. A comparison between our results and theoretical calculations is presented. Losses due to edge effects have been separated from losses due to the bona-fide reaction of protons in the scintillator with the aid of Multi-Wire Proportional Chamber (MWPC) trajectory information. The number of events associated with reaction losses was found to range from 10% to 25% of the total number of events, depending on the incident proton kinetic energy. (Author) (12 refs., tab., 2 figs.)

  19. Great scintillating properties of a YAlO sub 3 :Ce crystal

    CERN Document Server

    Gou Quan Bu; Li Zu Hao; Zhu Guo Yi; He Jing Tang; Tang Xiao Wei

    2002-01-01

    The authors study the decay time constants and light output of an 18 x 18 x 1 mm sup 3 YAlO sub 3 crystal doped with cerium. The result shows that the light pulse is composed of fast and slow components. The fast component has a decay time constant of 24.05 +- 0.15 ns with an intensity of 81.57 +- 0.97% and the slow component has a decay time constant of 87.67 +- 2.49 ns with an intensity of 18.51 +- 1.34%. The measured light output is 3608 +- 80 photoelectrons/MeV without the correction for the quantum efficiency of the photomultiplier tube XP2262B

  20. Machining of scintillator tiles for the SDC calorimeter

    International Nuclear Information System (INIS)

    Bertoldi, M.; Bartosz, E.; Davis, C.; Hagopian, V.; Hernandez, E.; Hu, K.; Immer, C.; Thomaston, J.

    1992-01-01

    This research and development on the grooving methods for the scintillating tiles of the SDC calorimeter was done to maximize the light output of scintillator plates and improve the uniformity among tiles through machining procedures. Grooves for wavelength shifting fibers in SCSN-81 can be machined from 10,000 to 60,000 RPM with a feed rate of more than 30cm/min if the plate is kept cool and the chips are removed quickly by blowing dry, cold, clean air over the cutting tool. BC499-27, a polystyrene-based scintillator, is softer and more difficult to machine. It allows a maximum rotation speed of 20,000 RPM and a maximum feed rate of 15 cm/min. A new half-keyhole shape was used for grooves, allowing safer, faster top-loading of the fibers. Three hundred tiles were machined, achieving a standard deviation of the light output of less than 7%. (Author)

  1. Novel thin-GaN LED structure adopted micro abraded surface to compare with conventional vertical LEDs in ultraviolet light

    Science.gov (United States)

    Chiang, Yen Chih; Lin, Chien Chung; Kuo, Hao Chung

    2015-04-01

    In this study, novel thin-GaN-based ultraviolet light-emitting diodes (NTG-LEDs) were fabricated using wafer bonding, laser lift-off, dry etching, textured surface, and interconnection techniques. Placing PN electrodes on the same side minimized the absorption caused by electrodes in conventional vertical injection light-emitting diodes (V-LEDs) and the current spreading was improved. The light output power (700 mA) of the NTG-LEDs was enhanced by 18.3% compared with that of the V-LEDs, and the external quantum efficiency (EQE) of the NTG-LEDs was also relatively enhanced by 20.0% compared with that of a reference device. When the current operations were 1,500 mA, the enhancements of the light output power and EQE were 27.4% and 27.2%, respectively. Additionally, the efficiency droop was improved by more than 15% at the same current level.

  2. The effect of radiation damage on optical and scintillation properties of BGO crystals grown by the LTG Cz technique

    CERN Document Server

    Gusev, V A; Kupriyanov, I N; Kuznecov, G N; Shlegel, V N; Antsygin, V D; Vasiliev, Y V

    2002-01-01

    BGO crystals grown by the low-thermal-gradient Czochralski technique (LTG Cz) exhibit two distinct types of behavior upon radiation damage and recovery. The crystals termed as of L-type remain colorless after gamma-radiation doses as high as 10 Mrad. As the irradiation dose increases the scintillation light output shows a weak monotonous degradation to 15-25%, saturating at around several hundreds krad doses. The crystals termed as of N-type attain yellow coloration after irradiation. The light output drops abruptly for 35-50% as early as after 1 krad and does not change further on. The present work is devoted to the study of radiation damage effects, self-recovery, optically stimulated recovery and thermo-stimulated current in the L- and N-type BGO crystals produced by LTG Cz.

  3. Scalability, Scintillation Readout and Charge Drift in a Kilogram Scale Solid Xenon Particle Detector

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, J. [Fermilab; Cease, H. [Fermilab; Jaskierny, W. F. [Fermilab; Markley, D. [Fermilab; Pahlka, R. B. [Fermilab; Balakishiyeva, D. [Florida U.; Saab, T. [Florida U.; Filipenko, M. [Erlangen - Nuremberg U., ECAP

    2014-10-23

    We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employ a liquid nitrogen cooled cryostat combined with a xenon purification and chiller system to measure the scintillation light output and electron drift speed from both the solid and liquid phases of xenon. Scintillation light output from sealed radioactive sources is measured by a set of high quantum efficiency photomultiplier tubes suitable for cryogenic applications. We observed a reduced amount of photons in solid phase compared to that in liquid phase. We used a conventional time projection chamber system to measure the electron drift time in a kilogram of solid xenon and observed faster electron drift speed in the solid phase xenon compared to that in the liquid phase.

  4. Light yield as a function of gas pressure and electric field in gas scintillation proportional counters

    International Nuclear Information System (INIS)

    Favata, F.; Smith, A.; Bavdaz, M.; Kowalski, T.Z.

    1990-01-01

    We have investigated the dependence of the scintillation light output for Xe on gas pressure in the range 0.14-1.4 bar, using a gas scintillation proportional counter, in different experimental configurations. We have compared our work with that of previous workers, and have shown that both our results and the results of previous authors are compatible with the intrinsic light output being independent of gas pressure, with any observed dependence being a pure experimental effect due to the spectral response of the various UV detectors used. We also use our experimental data for determining the ratio between the cross section of the Xe 2 ** +Xe→Xe 2 * +Xe reaction and the rate of the Xe 2 ** →2Xe+γ UV reaction. (orig.)

  5. The aluminization of 600k WLS fibers for the TileCal/ATLAS/LHC

    CERN Document Server

    Saraiva, J G; Maneira, M J P; Patriarca, J; Wemans, A

    2003-01-01

    The TILE CALorimeter, the hadronic sampling calorimeter of ATLAS/LHC /CERN, is made of iron and polystyrene scintillating tiles. The light produced in scintillating tiles is absorbed and guided to the photomultipliers (PMTs) through Wave Length Shifter (WLS) optical fibers. To optimize the detection of jets and muons, the top of the fibers away of the PMTs is coated with an aluminum mirror, that increases the light output in asymptotically equal to 75% and enhances the uniformity light output by asymptotically equal to 10%. The aluminum mirror is produced by Magnetron Sputtering, that adds to an excellent reproducibility a minimal thermal aggression important for proper film adhesion to the plastic surface. A dedicated machine for mass production of the ATLAS WLS aluminized fibers has been designed and constructed fulfilling the critical production optical and time requirements. The aluminization of the fibers and their quality control started in August 1999 and went on continuously until May 2002. The qualit...

  6. Characteristics of plastic scintillators fabricated by a polymerization reaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Cheol Ho; Son, Jaebum; Kim, Tae Hoon; Kim, Yong Kyun [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of)

    2017-04-15

    Three plastic scintillators of 4.5 cm diameter and 2.5-cm length were fabricated for comparison with commercial plastic scintillators using polymerization of the styrene monomer 2.5-diphenyloxazole (PPO) and 1,4-bis benzene (POPOP). Their maximum emission wavelengths were determined at 426.06 nm, 426.06 nm, and 425.00 nm with a standard error of 0.2% using a Varian spectrophotometer (Agilent, Santa Clara, CA, USA). Compton edge spectra were measured using three gamma ray sources [i.e., cesium 137 ({sup 137}Cs), sodium 22 ({sup 22}Na), and cobalt 60 ({sup 60}Co)]. Energy was calibrated by analyzing the Compton edge spectra. The fabricated scintillators possessed more than 99.7% energy linearity. Light output was comparable to that of the BC-408 scintillator (Saint-Gobain, Paris, France). The fabricated scintillators showed a light output of approximately 59–64% of that of the BC-408 scintillator.

  7. Tailoring of polarization in electron blocking layer for electron confinement and hole injection in ultraviolet light-emitting diodes

    International Nuclear Information System (INIS)

    Lu, Yu-Hsuan; Pilkuhn, Manfred H.; Fu, Yi-Keng; Chu, Mu-Tao; Huang, Shyh-Jer; Su, Yan-Kuin; Wang, Kang L.

    2014-01-01

    The influence of the AlGaN electron blocking layer (EBL) with graded aluminum composition on electron confinement and hole injection in AlGaN-based ultraviolet light-emitting diodes (LEDs) are investigated. The light output power of LED with graded AlGaN EBL was markedly improved, comparing to LED with conventional EBL. In experimental results, a high increment of 86.7% can be obtained in light output power. Simulation analysis shows that via proper modification of the barrier profile from the last barrier of the active region to EBL, not only the elimination of electron overflow to p-type layer can be achieved but also the hole injection into the active region can be enhanced, compared to a conventional LED structure. The dominant factor to the performance improvement is shown to be the modulation of polarization field by the graded Al composition in EBL

  8. Tailoring of polarization in electron blocking layer for electron confinement and hole injection in ultraviolet light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yu-Hsuan; Pilkuhn, Manfred H. [Department of Electrical Engineering, Institute of Microelectronics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Fu, Yi-Keng; Chu, Mu-Tao [Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan (China); Huang, Shyh-Jer, E-mail: yksu@mail.ncku.edu.tw, E-mail: totaljer48@gmail.com [Department of Electrical Engineering, Institute of Microelectronics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, California 90095 (United States); Su, Yan-Kuin, E-mail: yksu@mail.ncku.edu.tw, E-mail: totaljer48@gmail.com [Department of Electrical Engineering, Institute of Microelectronics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Electronic Engineering, Kun-Shan University, Tainan 71003, Taiwan (China); Wang, Kang L. [Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, California 90095 (United States)

    2014-03-21

    The influence of the AlGaN electron blocking layer (EBL) with graded aluminum composition on electron confinement and hole injection in AlGaN-based ultraviolet light-emitting diodes (LEDs) are investigated. The light output power of LED with graded AlGaN EBL was markedly improved, comparing to LED with conventional EBL. In experimental results, a high increment of 86.7% can be obtained in light output power. Simulation analysis shows that via proper modification of the barrier profile from the last barrier of the active region to EBL, not only the elimination of electron overflow to p-type layer can be achieved but also the hole injection into the active region can be enhanced, compared to a conventional LED structure. The dominant factor to the performance improvement is shown to be the modulation of polarization field by the graded Al composition in EBL.

  9. Improving Light Outcoupling Efficiency for OLEDs with Microlens Array Fabricated on Transparent Substrate

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2014-01-01

    Full Text Available Low light outcoupling efficiency restricts the wide application of organic light-emitting diodes in solid state light market although the internal quantum efficiency of the device could reach near to 100%. In order to improve the output efficiency, different kinds of microlens array on the substrate emission surface were designed and simulated using light tracing method. Simulation results indicate that the microlens array on the substrate could efficiently improve the light output efficiency and an enhancement of 1.8 could be obtained with optimized microlens structure design. The microlens array with semicircle shape using polymer material was fabricated on glass substrate by a facile approach. Finally, the organic device with microlens array substrate was manufactured and the light output of the device with surface microlens structure could increase to 1.64 times comparing with the device without microlens.

  10. Tests on a digital neutron-gamma pulse shape discriminator with NE213

    International Nuclear Information System (INIS)

    Bell, Z.W.

    1981-01-01

    A technique using charge sensitive analog-to-digital converters to do neutron-gamma pulse shape discrimination is reported. The converters are gated by short (135 ns) pulses so as to reduce pile-up and the timing is such that the slow and total light output from the scintillator are measured. Preliminary tests indicate that the system performs reasonably well but poorer than some reported analog systems employing gated integrators or cross-over techniques. (orig.)

  11. Scintillator for radiation detection and process for producing the same

    International Nuclear Information System (INIS)

    Ishii, M.; Akiyama, S.; Ishibashi, H.

    1985-01-01

    A scintillator for radiation detection obtained by coating a light reflective material in a thickness of 50 to 150 μm by a screen printing method on the surface of a solid scintillator material substrate is excellent in uniformity, dimensional accuracy with high light output. When the light reflective material layer is covered with a synthetic resin film, adhesive strength of the light reflective material layer to the substrate is increased remarkably

  12. Monte Carlo model of light transport in scintillating fibers and large scintillators

    International Nuclear Information System (INIS)

    Chakarova, R.

    1995-01-01

    A Monte Carlo model is developed which simulates the light transport in a scintillator surrounded by a transparent layer with different surface properties. The model is applied to analyse the light collection properties of scintillating fibers and a large scintillator wrapped in aluminium foil. The influence of the fiber interface characteristics on the light yield is investigated in detail. Light output results as well as time distributions are obtained for the large scintillator case. 15 refs, 16 figs

  13. A multi-GHz chaotic optoelectronic oscillator based on laser terminal voltage

    International Nuclear Information System (INIS)

    Chang, C. Y.; Choi, Daeyoung; Locquet, A.; Wishon, Michael J.; Citrin, D. S.; Merghem, K.; Ramdane, Abderrahim; Martinez, A.; Lelarge, François

    2016-01-01

    A multi-GHz chaotic optoelectronic oscillator based on an external cavity semiconductor laser (ECL) is demonstrated. Unlike the standard optoelectronic oscillators for microwave applications, we do not employ the dynamic light output incident on a photodiode to generate the microwave signal, but instead generate the microwave signal directly by measuring the terminal voltage V(t) of the laser diode of the ECL under constant-current operation, thus obviating the photodiode entirely.

  14. Measurements of the radiation hardness of selected scintillating and light guide fiber materials

    OpenAIRE

    Aschenauer, E. C.; Baehr, J.; Nahnhauer, R.; Shanidze, R.; Fink, D.; Maier, K. H.; Muller, M.; Klose, H. A.; Sprenger, M.

    1999-01-01

    Radiation hardness studies of KURARAY SCSF-78M scintillating fibers and clear fibers from KURARAY and pol.hi.tech. performed under different dose rate conditions in proton and electron beams are summarized. For high dose rates in-situ measurements of the fiber light output were done. During several months after irradiation all fibers were measured concerning light emission and transparency. Fibers irradiated at high rates to about 1 Mrad are clearly damaged but recover within a few hours up t...

  15. Effects of residential energy-saving lamps on the attraction of nocturnal insects

    OpenAIRE

    Poiani, S. [UNESP; Dietrich, C. [UNESP; Barroso, A.; Costa-Leonardo, Ana Maria [UNESP

    2015-01-01

    Many species of insects display a disposition to move towards light. As a consequence, nocturnal artificial lighting often contributes to an increase in insect population among humans. We tested the hypothesis that residential white lamps can evoke significantly different attraction to insects even when their light outputs are nearly indistinguishable to humans. In a two-choice experiment using insect traps equipped with either a compact fluorescent or a LED light source with similar photomet...

  16. Radiation damage of tile/fiber scintillator modules for the SDC calorimeter

    International Nuclear Information System (INIS)

    Hu, L.; Liu, N.; Mao, H.; Tan, Y.; Wang, G.; Zhang, C.; Zhang, G.; Zhang, L.; Zhang, Z.; Zhao, X.; Zheng, L.; Zhong, X.; Zhou, Y.; Han, S.; Byon, A.; Green, D.; Para, A.; Johnson, K.; Barnes, V.

    1992-02-01

    The measurements of radiation damage of tile/fiber scintillator modules to be used for the SDC calorimeter are described. Four tile/fiber scintillator modules were irradiated up to 6 Mrad with the BEPC 1.1 GeV electron beam. We have studied the light output at different depths in the modules and at different integrated doses, the recovery process and the dependence on the ambient atmosphere

  17. Bright Eu2+-activated polycrystalline ceramic neutron scintillators

    Science.gov (United States)

    Wang, C. L.; Paranthaman, M. P.; Riedel, R. A.; Hodges, J. P.; Karlic, J. J.; Veatch, R. A.; Li, L.; Bridges, C. A.

    2018-03-01

    Scintillation properties of Eu2+-doped CaF2-AlF3-6LiF (Eu:CALF) polycrystalline ceramic thermal-neutron scintillators as a function of AlF3 concentration have been studied. The emission band peaked at a wavelength of 425-431 nm is due to the presence of Eu:CaF2 micro-crystallites. The highest light output from these samples is approximately 20,000 photons per thermal neutron, which is 3 times that of a GS20 6Li-glass scintillator. The pulse-decay lifetime and light output vs. AlF3 concentration may be understood using a radiation trapping model and the formation of a Li3AlF6 phase. At lower AlF3 concentration, Al3+ ions in Eu:CaF2 passivate the hole-trapping defects and enhance the light output; whereas at higher AlF3 concentration, Al3+ ions lead to the formation of electron trapping centers in Eu:CaF2 and the Li3AlF6 phase is formed, which reduces the light output. A neutron-gamma-discrimination (NGD) ratio of 9 × 108 was obtained from Principal Component Analysis (PCA) of digital waveforms, while Fisher Linear Discriminant Analysis (FLDA) can completely separate the thermal neutrons from 60Co gamma rays within the limit of gamma event statistics used in this work. Our results suggest that Eu:CALF scintillators can potentially replace the GS20 scintillator used for thermal and cold neutron detection systems.

  18. The University of Queensland échelle spectrograph.

    Science.gov (United States)

    Porter, M. J.

    1996-11-01

    Many stars display variations in their light output. These variable stars are commonly studied using stellar photometry. In some cases, however, the variations are irregular with sudden "outbursts" occurring. In these cases the availability of more advanced instrumentation, such as spectrographs, would be desirable. This paper describes the University of Queensland échelle spectrograph, which is being developed for use as part of an automated photometric observing system.

  19. Scintillation response of nuclear particle detectors

    International Nuclear Information System (INIS)

    Michaelian, K.; Menchaca-Rocha, A.; Belmont-Moreno, E.

    1995-01-01

    We derive simple algebraic expressions for the ion-induced light output response of most of the popular scintillation detectors used in nuclear and particle physics. The analytical calculation is based on a model for the energy deposition by secondary electrons scattered along the track of the ion, and the subsequent energy transport to luminescence centers. Predictions are compared with published experimental data for various scintillating materials over a wide range of incident ions and energies. ((orig.))

  20. CALiPER Exploratory Study. Recessed Troffer Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Royer, M. P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Poplawski, M. E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-03-01

    This CALiPER study examines the problems and benefits likely to be encountered with LED products intended to replace linear fluorescent lamps. LED dedicated troffers, replacement tubes, and non-tube retrofit kits were evaluated against fluorescent benchmark troffers in a simulated office space for photometric distribution, uniformity of light on the task surface, suitability of light output, flicker, dimming performance, color quality, power quality, safety and certification issues, ease of installation, energy efficiency, and life-cycle cost.

  1. A monitor for neutron flux measurements up to 20 MeV.

    Science.gov (United States)

    Ohrn, A; Blomgren, J; Park, H; Khurana, S; Nolte, R; Schmidt, D; Wilhelmsen, K

    2007-01-01

    A liquid scintillation detector aimed for neutron energy and fluence measurements in the energy region neutron fields. Careful measurements of the proton light output function and the response matrix have been performed allowing for the application of unfolding techniques using existing codes. The response matrix is used to characterise monoenergetic neutron fields produced by the T(d,n) at a low-energy deuteron accelerator installed at the Swedish Defense Research Agency (FOI).

  2. Salient features in the preparation of gaseous tritium filled luminous light sources

    International Nuclear Information System (INIS)

    Mathew, K.M.; Ravi, S.; Subramanian, T.K.; Ananthakrishnan, M.

    2003-01-01

    Beta radiation emanating from gaseous tritium in close proximity with copper activated zinc sulphide phosphor provides self sustained light sources and these sources are used for nocturnal illumination of liquid crystal display in digital watches and clocks, product advertisements, exit signs etc. We report herein the preparation of low specific radioactivity gaseous tritium (29.5 Ci/m mole; 1.09 TBq/m mole) filled light sources and its effect on light output. (author)

  3. Toxicity assessment of reference and natural freshwater sediments with the luminotox assay

    CSIR Research Space (South Africa)

    Dellamatrice, PM

    2006-08-01

    Full Text Available reading tube. The light output of all tubes (sediment-exposed and controls) is measured with a photo- meter, after which inhibition percentages can be calculated. 396 DELLAMATRICE ET AL. Environmental Toxicology DOI 10.1002/tox The determined endpoint... photosynthetic enzyme complexes (PECs), iso- lated from spinach plant extracts. When PECs are chal- lenged with chemicals or complex samples that can inter- fere with transmission of chlorophyll fluorescence linked to Photosystems I and II reaction sites, a...

  4. Study of true-remanent polarization using remanent hysteresis task and resistive leakage analysis in ferroelectric 0.64Pb(Mg1/3Nb2/3)O3-0.36PbTiO3 ceramics

    Science.gov (United States)

    Joseph, Abhilash J.; Kumar, Binay

    2018-03-01

    The conventionally reported value of remanent polarization (Pr) contains contribution from non-remanent components which are not usable for memory device applications. This report presents techniques which extract the true-remanent (intrinsic) component of polarization after eliminating the non-remanent component in ferroelectric ceramics. For this, "remanent hysteresis task" and "positive-up-negative-down technique" were performed which utilized the switchable properties of polarizations to nullify the contributions from the non-remanent (non-switchable) components. The report also addresses the time-dependent leakage behavior of the ceramics focusing on the presence of resistive leakage (a time-dependent parameter) present in the ceramics. The techniques presented here are especially useful for polycrystalline ceramics where leakage current leads to an erroneous estimation of Pr.

  5. Dynamic Softening or Stiffening a Supramolecular Hydrogel by Ultraviolet or Near-Infrared Light.

    Science.gov (United States)

    Zheng, Zhao; Hu, Jingjing; Wang, Hui; Huang, Junlin; Yu, Yihua; Zhang, Qiang; Cheng, Yiyun

    2017-07-26

    The development of light-responsive hydrogels that exhibit switchable size and mechanical properties with temporal and spatial resolution is of great importance in many fields. However, it remains challenging to prepare smart hydrogels that dramatically change their properties in response to both ultraviolet (UV) and near-infrared (NIR) lights. Here, we designed a dual-light responsive supramolecular gel by integrating UV light-switchable host-guest recognition, temperature responsiveness, and NIR photothermal ability in the gel. The gel could rapidly self-heal and is capable of both softening and stiffening controlled by UV and NIR lights, respectively. Besides stiffness modulation, the bending direction of the gel can be controlled by UV or NIR light irradiation. The smart gel makes it possible to generate dynamic materials that respond to both UV and NIR lights and represents a useful tool that might be used to modulate cellular microenvironments with spatiotemporal resolution.

  6. Breaking the diffraction limit of light-sheet fluorescence microscopy by RESOLFT.

    Science.gov (United States)

    Hoyer, Patrick; de Medeiros, Gustavo; Balázs, Bálint; Norlin, Nils; Besir, Christina; Hanne, Janina; Kräusslich, Hans-Georg; Engelhardt, Johann; Sahl, Steffen J; Hell, Stefan W; Hufnagel, Lars

    2016-03-29

    We present a plane-scanning RESOLFT [reversible saturable/switchable optical (fluorescence) transitions] light-sheet (LS) nanoscope, which fundamentally overcomes the diffraction barrier in the axial direction via confinement of the fluorescent molecular state to a sheet of subdiffraction thickness around the focal plane. To this end, reversibly switchable fluorophores located right above and below the focal plane are transferred to a nonfluorescent state at each scanning step. LS-RESOLFT nanoscopy offers wide-field 3D imaging of living biological specimens with low light dose and axial resolution far beyond the diffraction barrier. We demonstrate optical sections that are thinner by 5-12-fold compared with their conventional diffraction-limited LS analogs.

  7. Large-area smart glass and integrated photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, C.M. [Star Science, 8730 Water Road, Cotati, CA 94931-4252 (United States)

    2003-04-01

    Several companies throughout the world are developing dynamic glazing and large-area flat panel displays. University and National Laboratory groups are researching new materials and processes to improve these products. The concept of a switchable glazing for building and vehicle application is very attractive. Conventional glazing only offers fixed transmittance and control of energy passing through it. Given the wide range of illumination conditions and glare, a dynamic glazing with adjustable transmittance offers the best solution. Photovoltaics can be integrated as power sources for smart windows. In this way a switchable window could be a completely stand alone smart system. A new range of large-area flat panel display including light-weight and flexible displays are being developed. These displays can be used for banner advertising, dynamic pricing in stores, electronic paper, and electronic books, to name only a few applications. This study covers selected switching technologies including electrochromism, suspended particles, and encapsulated liquid crystals.

  8. Switching between transparent and translucent states of a two-dimensional liquid crystal phase grating device with crossed interdigitated electrodes.

    Science.gov (United States)

    Choi, Tae-Hoon; Huh, Jae-Won; Woo, Jae-Hyeon; Kim, Jin-Hun; Jo, Young-Seo; Yoon, Tae-Hoon

    2017-05-15

    We report an electrically-switchable two-dimensional liquid crystal (LC) phase grating device for window display applications. The device consists of the top and bottom substrates with crossed interdigitated electrodes and vertically-aligned LCs sandwiched between the two substrates. The device, switchable between the transparent and translucent states by applying an electric field, can provide high haze by the strong diffraction effect thanks to a large spatial phase difference with little dependence on the azimuth angle. We found that the device has outstanding features, such as a low operating voltage, high transparency, and wide viewing angle characteristics in the transparent state and high haze in the translucent state. Moreover, we achieved submillisecond switching between transparent and translucent states by employing the overdrive scheme and a vertical trigger pulse.

  9. Self-adjusting smart windows based on polymer-dispersed liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Cupelli, Daniela; Pasquale Nicoletta, Fiore; Vivacqua, Marco; Formoso, Patrizia [Dipartimento di Scienze Farmaceutiche, Universita della Calabria, 87036 Rende (CS) (Italy); Manfredi, Sabrina; De Filpo, Giovanni; Chidichimo, Giuseppe [Dipartimento di Chimica, Universita della Calabria, 87036 Rende (CS) (Italy)

    2009-11-15

    The control of sunlight can be achieved either by electrochromic or polymer-dispersed liquid crystal (PDLC) smart windows. We have recently shown that it is possible to homeotropically align fluid mixtures of low molecular mass liquid crystal with a negative dielectric anisotropy, and a liquid crystalline monomer, in order to obtain electrically switchable chromogenic devices. They are new materials useful for external glazing. In fact, they are not affected by the classical drawbacks of PDLCs. In this paper we present a new self-switchable glazing technology based on the light-controlled transmittance in a PDLC device. The self-adjusting chromogenic material, which we obtain, is able to self-increase its scattering as a function of the impinging light intensity. The relationship between the electro-optical response and the physical-chemical properties of the components has been also investigated. (author)

  10. Thermoresponsive electrospun fibers for water harvesting applications

    Science.gov (United States)

    Thakur, Neha; Baji, Avinash; Ranganath, Anupama Sargur

    2018-03-01

    Temperature triggered switchable cellulose acetate-poly(N-isopropylacrylamide) (CA-PNIPAM) core-shell and blend nanofibers are fabricated for controlled moisture harvesting applications. Core-shell fibers are fabricated using a co-axial electrospinning setup whereas the conventional electrospinning setup is employed for fabricating the blend fibers. Investigation of their wettability behaviour demonstrated that the blend fibers are superhydrophilic whereas the core-shell fibers are hydrophilic at ambient temperature. Furthermore, both the samples have an ability to switch between the two states viz. hydrophilic to hydrophobic state based on thermal stimulus. The core-shell fibers are shown to have higher moisture sorption ability compared to the blend fibers. This study investigates the mechanism behind the switchable wettability behaviour of the core-shell fibers and demonstrates the crucial role played by the functional groups present on the surface layer of fibers in governing their moisture collection efficiency.

  11. Silicon photonic processor of two-qubit entangling quantum logic

    Science.gov (United States)

    Santagati, R.; Silverstone, J. W.; Strain, M. J.; Sorel, M.; Miki, S.; Yamashita, T.; Fujiwara, M.; Sasaki, M.; Terai, H.; Tanner, M. G.; Natarajan, C. M.; Hadfield, R. H.; O'Brien, J. L.; Thompson, M. G.

    2017-11-01

    Entanglement is a fundamental property of quantum mechanics, and is a primary resource in quantum information systems. Its manipulation remains a central challenge in the development of quantum technology. In this work, we demonstrate a device which can generate, manipulate, and analyse two-qubit entangled states, using miniature and mass-manufacturable silicon photonics. By combining four photon-pair sources with a reconfigurable six-mode interferometer, embedding a switchable entangling gate, we generate two-qubit entangled states, manipulate their entanglement, and analyse them, all in the same silicon chip. Using quantum state tomography, we show how our source can produce a range of entangled and separable states, and how our switchable controlled-Z gate operates on them, entangling them or making them separable depending on its configuration.

  12. Radiation damage of CsI(Tl) scintillators: blocking of energy transfer process of V sub k centers to Tl sup + activators

    CERN Document Server

    Hamada, M M; Shimizu, S; Kubota, S

    2002-01-01

    This paper reports the emission spectra, light output, transmission and decay curves of CsI(Tl) crystals irradiated with gamma rays at different doses, ranging from 1x10 sup 5 to 5x10 sup 5 Gy. The crystals were coated with black or white tapes. Significant decreases in the emission spectra and light output values were observed for the crystals coated with white tape as the radiation dose increased. The decrease in the degree of the rising part of the decay curve in the irradiated crystals is attributed to the blocking of the energy transfer processes of V sub k lattice disorders, which were produced in irradiated crystals. The scintillation mechanism is affected in the crystal irradiated at 5x10 sup 5 Gy. However for crystals irradiated below 10 sup 5 Gy the mechanism process is not altered, and the decrease in the light output is due to internal transmission loss. It was also observed that the damage for irradiation is not permanent and it obeys a bi-exponential function.

  13. Study of polystyrene scintillators-WLS fiber elements and scintillating tile-WLS prototypes for New CHOD detector of CERN NA-62 experiment

    CERN Document Server

    Semenov, Vitaliy; Gorin, Aleksandr; Khudyakov, Aleksey; Rykalin, Vladimir; Yushchenko, Oleg

    2016-01-01

    We measured the light output and the time resolution of few sets comprised of polystyrene scintillator and wavelength shifting (WLS) fibers as readout. The samples of different thickness (7-30 mm) have been made in the shape of bricks and plates with the areas of 25×80, 108×134 and 108×268 of mm2. In addition to samples of “ordinary” scintillator with additions of 2% p- Terphenyl + 0.05% POPOP, the rapid ultraviolet scintillator with single 2% additive PBD was tested. For the light collection WLS-fibers BCF92, Y11 and scintillation fiber SCSF-78M as reemitting were checked. The fibers were glued into the grooves on the front surface of scintillators. As the photo detectors silicon photomultipliers (SiPM) produced by CPTA (Russia) and SensL (Ireland) were used. It is shown that the dependence of light output on the thickness of scintillator is nonlinear and close to the square root function, which is also confirmed by the calculations carried out by Monte Carlo. The measured value of a light output make...

  14. Performance of the Commercial PP/ZnS:Cu and PP/ZnS:Ag Scintillation Screens for Fast Neutron Imaging

    Directory of Open Access Journals (Sweden)

    Malgorzata G. Makowska

    2017-12-01

    Full Text Available Fast neutron imaging has a great potential as a nondestructive technique for testing large objects. The main factor limiting applications of this technique is detection technology, offering relatively poor spatial resolution of images and low detection efficiency, which results in very long exposure times. Therefore, research on development of scintillators for fast neutron imaging is of high importance. A comparison of the light output, gamma radiation sensitivity and spatial resolution of commercially available scintillator screens composed of PP/ZnS:Cu and PP/ZnS:Ag of different thicknesses are presented. The scintillators were provided by RC Tritec AG company and the test performed at the NECTAR facility located at the FRM II nuclear research reactor. It was shown that light output increases and the spatial resolution decreases with the scintillator thickness. Both compositions of the scintillating material provide similar light output, while the gamma sensitivity of PP/ZnS:Cu is significantly higher as compared to PP/ZnS:Ag-based scintillators. Moreover, we report which factors should be considered when choosing a scintillator and what are the limitations of the investigated types of scintillators.

  15. New scintillating media based on liquid crystals for particle detectors

    CERN Document Server

    Barnik, M I; Vasilchenko, V G; Golovkin, S V; Medvedkov, A M; Soloviev, A S

    2000-01-01

    The study results of optical, photoluminiscent and scintillation properties of a liquid crystal 4-pentyl-4'-cyanobiphenyl are presented. The scintillation light output of this liquid crystal is about 35% of crystal anthracene, its main decay time constants are 4 and 14 ns, and the maximum of light emission spectrum is about 400 nm. The light output of a dissolution of green emitting light scintillation dopant R6 in the liquid crystal is about 120% of crystal anthracene. The light output of the frozen dissolution measured at -112 deg. C is about 2.5 times higher as observed at +20 deg. C. In the uniaxially oriented liquid crystal, the predominant intensity direction of emitted light is pointed perpendicular to the liquid crystal director and an appreciable part of the emitted light is elliptically polarized. The possibility to use scintillation properties of liquid crystals is considered both for the improvement of existing particle detector characteristics and for the creation of new gated particle detectors.

  16. Response and calibration of organic scintillators for gamma-ray spectroscopy up to 15-MeV range

    Science.gov (United States)

    Nattress, J.; Jovanovic, I.

    2017-11-01

    We present a calibration method for an organic scintillator suitable for gamma energies of up to 15 MeV. We use a combination of experiments and simulations to identify prominent features in the light output spectra to provide an accurate calibration method over this energy range. Gamma energies in the range of 0.511 MeV to 15.1 MeV were used to perform two separate calibrations to the measured light output expressed in the units of electron equivalent energy. The first method strictly uses the well-known technique of identifying the Compton edges, while the second utilizes a combination of Compton edges and double escape peaks for several gamma energies. We performed a least-squares test to the high end of the light output spectra for a 15.1 MeV gamma ray to assess the accuracy of the two methods. The calibration technique that employs a combination of Compton edges and escape peaks yielded a significant improvement in accuracy when compared to a calibration that relies solely on the use of Compton edges.

  17. Formation of an indium tin oxide nanodot/Ag nanowire electrode as a current spreader for near ultraviolet AlGaN-based light-emitting diodes.

    Science.gov (United States)

    Park, Jae-Seong; Kim, Jae-Ho; Kim, Jun-Yong; Kim, Dae-Hyun; Na, Jin-Young; Kim, Sun-Kyung; Kang, Daesung; Seong, Tae-Yeon

    2017-01-27

    Indium tin oxide (ITO) nanodots (NDs) were combined with Ag nanowires (Ag NWs) as a p-type electrode in near ultraviolet AlGaN-based light-emitting diodes (LEDs) to increase light output power. The Ag NWs were 30 ± 5 nm in diameter and 25 ± 5 μm in length. The transmittance of 10 nm-thick ITO-only was 98% at 385 nm, while the values for ITO ND/Ag NW were 83%-88%. ITO ND/Ag NW films showed lower sheet resistances (32-51 Ω sq -1 ) than the ITO-only film (950 Ω sq -1 ). LEDs (chip size: 300 × 800 μm 2 ) fabricated using the ITO NDs/Ag NW electrodes exhibited higher forward-bias voltages (3.52-3.75 V at 20 mA) than the LEDs with the 10 nm-thick ITO-only electrode (3.5 V). The LEDs with ITO ND/Ag NW electrodes yielded a 24%-62% higher light output power (at 20 mA) than those with the 10 nm-thick ITO-only electrode. Furthermore, finite-difference time-domain (FDTD) simulations were performed to investigate the extraction efficiency. Based on the emission images and FDTD simulations, the enhanced light output with the ITO ND/Ag NW electrodes is attributed to improved current spreading and better extraction efficiency.

  18. Chemiluminescent detection systems of horseradish peroxidase employing nucleophilic acylation catalysts.

    Science.gov (United States)

    Marzocchi, Ettore; Grilli, Stefano; Della Ciana, Leopoldo; Prodi, Luca; Mirasoli, Mara; Roda, Aldo

    2008-06-15

    The light output of the peroxidase-catalyzed luminol chemiluminescent oxidation reaction can be greatly increased by incorporating different enhancers. Such an increase is attributed to the preferential oxidation of the enhancer by peroxidase intermediates and the rapid formation of enhancer radicals that, in turn, quickly oxidize luminol to its radical anion. These enhancers, which include substituted phenols, substituted boronic acids, indophenols, and N-alkyl phenothiazines, behave as electron transfer mediators. A further, very significant increase in light output was also observed by the addition of nucleophilic acylation catalyst to the enhancer/luminol/oxidant substrate. The effect of the new component is general and applicable to many of the known enhancers but is much more remarkable in association with phenothiazine enhancers (up to 10-fold light output). The addition of a nucleophilic acylation catalyst to these substrates lowered the limit of detection for horseradish peroxidase from 50 to 8 amol. Similar improvements were observed in "sandwich" enzyme-linked immunosorbent assays and Western blot assays.

  19. Amorphous silicon pixel layers with cesium iodide converters for medical radiography

    International Nuclear Information System (INIS)

    Jing, T.; Cho, G.; Goodman, C.A.

    1993-11-01

    We describe the properties of evaporated layers of Cesium Iodide (Thallium activated) deposited on substrates that enable easy coupling to amorphous silicon pixel arrays. The CsI(Tl) layers range in thickness from 65 to 220μm. We used the two-boat evaporator system to deposit CsI(Tl) layers. This system ensures the formation of the scintillator film with homogenous thallium concentration which is essential for optimizing the scintillation light emission efficiency. The Tl concentration was kept to 0.1--0.2 mole percent for the highest light output. Temperature annealing can affect the microstructure as well as light output of the CsI(Tl) film. 200--300C temperature annealing can increase the light output by a factor of two. The amorphous silicon pixel arrays are p-i-n diodes approximately lμm thick with transparent electrodes to enable them to detect the scintillation light produced by X-rays incident on the CsI(Tl). Digital radiography requires a good spatial resolution. This is accomplished by making the detector pixel size less then 50μm. The light emission from the CsI(Tl) is collimated by techniques involving the deposition process on pattered substrates. We have measured MTF of greater than 12 line pairs per mm at the 10% level

  20. Smart worm-like micelles responsive to CO2/N2 and light dual stimuli.

    Science.gov (United States)

    Jiang, Jianzhong; Wang, Guozheng; Ma, Yuxuan; Cui, Zhenggang; Binks, Bernard P

    2017-04-12

    CO 2 /N 2 and light dual stimuli-responsive worm-like micelles (WLMs) were obtained by addition of a relatively small amount of a switchable surfactant, 4-butyl-4'-(4-N,N-dimethylhexyloxy-amine) azobenzene bicarbonate (AZO-B6-CO 2 ), sensitive to the same triggers to a binary aqueous solution of cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal).

  1. In vivo super-resolution RESOLFT microscopy of Drosophila melanogaster.

    OpenAIRE

    Schnorrenberg, Sebastian; Grotjohann, Tim; Vorbrüggen, Gerd; Herzig, Alf; Hell, Stefan W.; Jakobs, Stefan

    2016-01-01

    Despite remarkable developments in diffraction unlimited super-resolution microscopy, in vivo nanoscopy of tissues and model organisms is still not satisfactorily established and rarely realized. RESOLFT nanoscopy is particularly suited for live cell imaging because it requires relatively low light levels to overcome the diffraction barrier. Previously, we introduced the reversibly switchable fluorescent protein rsEGFP2, which facilitated fast RESOLFT nanoscopy (Grotjohann et al., 2012). In t...

  2. Two-color RESOLFT nanoscopy with green and red fluorescent photochromic proteins.

    OpenAIRE

    Lavoie-Cardinal, Flavie; Jensen, Nickels A.; Westphal, Volker; Stiel, Andre C.; Chmyrov, Andriy; Bierwagen, Jakob; Testa, Ilaria; Jakobs, Stefan; Hell, Stefan W.

    2014-01-01

    Up to now, all demonstrations of reversible saturable optical fluorescence transitions (RESOLFT) superresolution microscopy of living cells have relied on the use of reversibly switchable fluorescent proteins (RSFP) emitting in the green spectral range. Here we show RESOLFT imaging with rsCherryRev1.4, a new red-emitting RSFP enabling a spatial resolution up to four times higher than the diffraction barrier. By co-expressing green and red RSFPs in living cells we demonstrate two-color RESOLFT...

  3. A Helical Flow, Circular Microreactor For Separating and Enriching “Smart” Polymer-Antibody Capture Reagents

    OpenAIRE

    Hoffman, John M.; Ebara, Mitsuhiro; Lai, James J.; Hoffman, Allan S.; Folch, Albert; Stayton, Patrick S.

    2010-01-01

    We report a mechanistic study of how flow and recirculation in a microreactor can be used to optimize the capture and release of stimuli-responsive polymer-protein reagents on stimuli-responsive polymer-grafted channel surfaces. Poly(N-isopropylacrylamide) (PNIPAAm) was grafted to poly(dimethyl)siloxane (PDMS) channel walls, creating switchable surfaces where PNIPAAm-protein conjugates would adhere at temperatures above the lower critical solution temperature (LCST) and released below the LCS...

  4. Pharmacological Regulation of Peroxisome Number in Glia

    Science.gov (United States)

    2008-09-01

    Proliferation The pharmaceutical manipulation of peroxisome number has a long and interesting history. In the 1970s, research was conducted on...montages to illustrate peroxisome morphology. These images were optimally contrasted before collation in Adobe Photoshop . Western blot...point, cells will be transfected with Pex16 fused to a photo -switchable fluorescent protein (Kim et al. 2006). The cells will then be washed out of

  5. Green Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Collison, Melanie

    2011-05-15

    Green chemistry is the science of chemistry used in a way that will not use or create hazardous substances. Dr. Rui Resendes is working in this field at GreenCentre Canada, an offshoot of PARTEQ Innovations in Kingston, Ontario. GreenCentre's preliminary findings suggest their licensed product {sup S}witchable Solutions{sup ,} featuring 3 classes of solvents and a surfactant, may be useful in bitumen oil sands extraction.

  6. Proton beam writing for producing holographic images

    International Nuclear Information System (INIS)

    Ow, Y.S.; Breese, M.B.H.; Bettiol, A.A.

    2009-01-01

    This work reports on the writing of computer generated hologram diffraction patterns using focused 2 MeV proton beam irradiation. These patterns were designed using a ray tracing algorithm and written directly into a thick polymethylmethacrylate layer. When the developed holographic pattern was illuminated with a 650 nm laser it produced a good reconstructed image. This work provides means of forming high-resolution, high aspect ratio holographic images in polymers for applications in data storage using switchable holography.

  7. A palladium-catalysed multicomponent coupling approach to conjugated poly(1,3-dipoles) and polyheterocycles

    OpenAIRE

    Leitch, David C.; Kayser, Laure V.; Han, Zhi-Yong; Siamaki, Ali R.; Keyzer, Evan N.; Gefen, Ashley; Arndtsen, Bruce A.

    2015-01-01

    Conjugated polymers have emerged over the past several decades as key components for a range of applications, including semiconductors, molecular wires, sensors, light switchable transistors and OLEDs. Nevertheless, the construction of many such polymers, especially highly substituted variants, typically involves a multistep synthesis. This can limit the ability to both access and tune polymer structures for desired properties. Here we show an alternative approach to synthesize conjugated mat...

  8. A robust smart window: reversibly switching from high transparency to angle-independent structural color display.

    Science.gov (United States)

    Ge, Dengteng; Lee, Elaine; Yang, Lili; Cho, Yigil; Li, Min; Gianola, Daniel S; Yang, Shu

    2015-04-17

    A smart window is fabricated from a composite consisting of elastomeric poly(dimethylsiloxane) embedded with a thin layer of quasi-amorphous silica nanoparticles. The smart window can be switched from the initial highly transparent state to opaqueness and displays angle-independent structural color via mechanical stretching. The switchable optical property can be fully recovered after 1000 stretching/releasing cycles. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The management and conversion of light

    DEFF Research Database (Denmark)

    Jensen, Jacob

    not affect the electrochromic properties. Electrochromic polymers show appreciable electrochemical stability, but the photochemically stability has never been thoroughly addressed. The stability of thin flexible organic electrochromic films are shown to depend on polymer composition and a hypothesis......Electrochromic conjugated polymers have during the last two decades shown promise as switchable components in displays, windows, signs and other optical applications. Properties such as response time, solubility, electrochemical stability, and color have been fine-tuned, but contrary...

  10. The unexpected influence of aryl substituents in N-aryl-3-oxobutanamides on the behavior of their multicomponent reactions with 5-amino-3-methylisoxazole and salicylaldehyde

    Directory of Open Access Journals (Sweden)

    Volodymyr V. Tkachenko

    2014-12-01

    Full Text Available The switchable three-component reactions of 5-amino-3-methylisoxazole, salicylaldehyde and N-aryl-3-oxobutanamides under different conditions were studied and discussed. The unexpected influence of the aryl substituent in N-aryl-3-oxobutanamides on the behavior of the reaction was discovered. The key influence of ultrasonication and Lewis acid catalysts led to an established protocol to selectively obtain two or three types of heterocyclic scaffolds depending on the substituent in the N-aryl moiety.

  11. Development of 3000 m Subsea Blowout Preventer Experimental Prototype

    Science.gov (United States)

    Cai, Baoping; Liu, Yonghong; Huang, Zhiqian; Ma, Yunpeng; Zhao, Yubin

    2017-12-01

    A subsea blowout preventer experimental prototype is developed to meet the requirement of training operators, and the prototype consists of hydraulic control system, electronic control system and small-sized blowout preventer stack. Both the hydraulic control system and the electronic system are dual-mode redundant systems. Each system works independently and is switchable when there are any malfunctions. And it significantly improves the operation reliability of the equipment.

  12. Programmable bioelectronics in a stimuli-encoded 3D graphene interfaces

    OpenAIRE

    Parlak, Onur; Beyazit, Selim; Tse Sum Bui, Bernadette; Haupt, Karsten; Turner, Anthony; Tiwari, Ashutosh

    2016-01-01

    The ability to program and mimic the dynamic microenvironment of living organisms is a crucial step towards the engineering of advanced bioelectronics. Here, we report for the first time a design for programmable bioelectronics, with ‘built-in’ switchable and tunable bio-catalytic performance that responds simultaneously to appropriate stimuli. The designed bio-electrodes comprise light and temperature responsive compartments, which allow the building of Boolean logic gates (i.e. “OR” and “AN...

  13. Phase-Change Memory Materials by Design: A Strain Engineering Approach.

    Science.gov (United States)

    Zhou, Xilin; Kalikka, Janne; Ji, Xinglong; Wu, Liangcai; Song, Zhitang; Simpson, Robert E

    2016-04-20

    Van der Waals heterostructure superlattices of Sb2 Te1 and GeTe are strain-engineered to promote switchable atomic disordering, which is confined to the GeTe layer. Careful control of the strain in the structures presents a new degree of freedom to design the properties of functional superlattice structures for data storage and photonics applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Magnetic Particle-Based Hybrid Platforms for Bioanalytical Sensors

    Directory of Open Access Journals (Sweden)

    Silvana Andreescu

    2009-04-01

    Full Text Available Biomagnetic nano and microparticles platforms have attracted considerable interest in the field of biological sensors due to their interesting physico-chemical properties, high specific surface area, good mechanical stability and opportunities for generating magneto-switchable devices. This review discusses recent advances in the development and characterization of active biomagnetic nanoassemblies, their interaction with biological molecules and their use in bioanalytical sensors.

  15. The abnormal photovoltaic effect in BiFeO3 thin films modulated by bipolar domain orientations and oxygen-vacancy migration

    Science.gov (United States)

    Bai, Zilong; Geng, Wenping; Zhang, Yan; Xu, Shuaiqi; Guo, Huizhen; Jiang, Anquan

    2017-08-01

    SrRuO3/BiFeO3/SrRuO3 thin-film capacitors were fabricated to investigate the role of mobile oxygen vacancies in a switchable photovoltaic (PV) effect that depends on ferroelectric domain orientations. Normally, the flowing direction of the stabilized photocurrent is opposite to ferroelectric polarization orientation. However, an abnormal overshoot of initial positive transient photocurrent parallel to the ferroelectric polarization could be observed under light illumination for a poled BiFeO3 thin film with the polarization pointing to the bottom electrode. Moreover, the photocurrent has a strong response with respect to voltage poling time and relaxation time after poling, which seems to be correlated with time-dependent migration of oxygen vacancies and concurrent charge trapping effect. Our results not only reveal the scenario how oxygen-vacancy migration and charge trapping effect affect the switchable PV effect, besides ferroelectric polarization, but also are helpful for the understanding and designing of new switchable photoelectric devices.

  16. Intermolecular Structural Change for Thermoswitchable Polymeric Photosensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Park, Wooram; Park, Sin-Jung [Center; Cho, Soojeong; Shin, Heejun [Center; Jung, Young-Seok [Center; Lee, Byeongdu [X-ray; Na, Kun [Center; Kim, Dong-Hyun

    2016-08-17

    A switchable photosensitizer (PS), which can be activated at a spe-cific condition beside light, has tremendous advantages for photo-dynamic therapy (PDT). Herein, we developed a thermo-switchable polymeric photosensitizer (T-PPS) by conjugating PS (Pheophor-bide-a, PPb-a) to a temperature-responsive polymer backbone of biocompatible hydroxypropyl cellulose (HPC). Self-quenched PS molecules linked in close proximity by pi-pi stacking in T-PPS were easily transited to an active monomeric state by the tempera-ture induced phase transition of polymer backbones. The tempera-ture responsive inter-molecular interaction changes of PS molecules in T-PPS were demonstrated in synchrotron small-angle X-ray scattering (SAXS) and UV-Vis spectrophotometer analysis. The T-PPS allowed switchable activation and synergistically enhanced cancer cell killing effect at the hyperthermia temperature (45 °C). Our developed T-PPS has the considerable potential not only as a new class of photomedicine in clinics but also as a biosensor based on temperature responsiveness.

  17. Dipole pinning effect on photovoltaic characteristics of ferroelectric BiFeO3 films

    Science.gov (United States)

    Biswas, P. P.; Thirmal, Ch.; Pal, S.; Murugavel, P.

    2018-01-01

    Ferroelectric bismuth ferrite is an attractive candidate for switchable devices. The effect of dipole pinning due to the oxygen vacancy layer on the switching behavior of the BiFeO3 thin film fabricated by the chemical solution deposition method was studied after annealing under air, O2, and N2 environment. The air annealed film showed well defined and dense grains leading to a lower leakage current and superior electrical properties compared to the other two films. The photovoltage and transient photocurrent measured under positive and negative poling elucidated the switching nature of the films. Though the air and O2 annealed films showed a switchable photovoltaic response, the response was severely affected by oxygen vacancies in the N2 annealed film. In addition, the open circuit voltage was found to be mostly dependent on the polarization of BiFeO3 rather than the Schottky barriers at the interface. This work provides an important insight into the effect of dipole pinning caused by oxygen vacancies on the switchable photovoltaic effect of BiFeO3 thin films along with the importance of stoichiometric, defect free, and phase pure samples to facilitate meaningful practical applications.

  18. Phototaxis of Cyanobacteria under Complex Light Environments

    Directory of Open Access Journals (Sweden)

    Minsu Kim

    2017-04-01

    Full Text Available Photosynthetic bacteria are capable of producing their own food via photosynthesis. Unsurprisingly, they evolved the ability to move toward better light conditions (i.e., phototaxis. In a recent article in mBio, Chau et al. tuned the wavelength, flux, direction, and timing of light input and characterized the motility of the unicellular cyanobacterium Synechocystis sp. strain PCC6803 (R. M. W. Chau, D. Bhaya, and K. C. Huang, mBio 8:e02330-16, 2017, https://doi.org/10.1128/mBio.02330-16. The results revealed an intricate dependence of the motility on various light inputs, laying the fundamental groundwork toward understanding phototaxis under complex and dynamic light environments.

  19. Calcium and SOL Protease Mediate Temperature Resetting of Circadian Clocks

    Science.gov (United States)

    Tataroglu, Ozgur; Zhao, Xiaohu; Busza, Ania; Ling, Jinli; O’Neill, John S.; Emery, Patrick

    2015-01-01

    Summary Circadian clocks integrate light and temperature input to remain synchronized with the day/night cycle. Although light input to the clock is well studied, the molecular mechanisms by which circadian clocks respond to temperature remain poorly understood. We found that temperature phase shifts Drosophila circadian clocks through degradation of the pacemaker protein TIM. This degradation is mechanistically distinct from photic CRY-dependent TIM degradation. Thermal TIM degradation is triggered by cytosolic calcium increase and CALMODULIN binding to TIM and is mediated by the atypical calpain protease SOL. This thermal input pathway and CRY-dependent light input thus converge on TIM, providing a molecular mechanism for the integration of circadian light and temperature inputs. Mammals use body temperature cycles to keep peripheral clocks synchronized with their brain pacemaker. Interestingly, downregulating the mammalian SOL homolog SOLH blocks thermal mPER2 degradation and phase shifts. Thus, we propose that circadian thermosensation in insects and mammals share common principles. PMID:26590423

  20. APPLICA TION OF OPTICAL LOGIC GATES Avireni Srinivasulu, L ...

    African Journals Online (AJOL)

    Figure 1 shows the circuit diagram of optical NOT with light input OPi. The light dependent resistor. LDR is connected in series to UJT emitter and the power supply +1.8V to the base B2 through a pair ... LDR2 are connected in parallel to the UJT emitter terminal. Optical output OPo of NOR occurs only when both the inputs ...

  1. Scintillation screen materials for beam profile measurements of high energy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Krishnakumar, Renuka

    2016-06-22

    For the application as a transverse ion beam diagnostics device, various scintillation screen materials were analysed. The properties of the materials such as light output, image reproduction and radiation stability were investigated with the ion beams extracted from heavy ion synchrotron SIS-18. The ion species (C, Ne, Ar, Ta and U) were chosen to cover the large range of elements in the periodic table. The ions were accelerated to the kinetic energies of 200 MeV/u and 300 MeV/u extracted with 300 ms pulse duration and applied to the screens. The particle intensity of the ion beam was varied from 10{sup 4} to 10{sup 9} particles per pulse. The screens were irradiated with typically 40 beam pulses and the scintillation light was captured using a CCD camera followed by characterization of the beam spot. The radiation hardness of the screens was estimated with high intensity Uranium ion irradiation. In the study, a linear light output for 5 orders of magnitude of particle intensities was observed from sensitive scintillators and ceramic screens such as Al{sub 2}O{sub 3}:Cr and Al{sub 2}O{sub 3}. The highest light output was recorded by CsI:Tl and the lowest one by Herasil. At higher beam intensity saturation of light output was noticed from Y and Mg doped ZrO{sub 2} screens. The light output from the screen depends not only on the particle intensity but also on the ion species used for irradiation. The light yield (i.e. the light intensity normalised to the energy deposition in the material by the ion) is calculated from the experimental data for each ion beam setting. It is shown that the light yield for light ions is about a factor 2 larger than the one of heavy ions. The image widths recorded exhibit a dependence on the screens material and differences up to 50 % were registered. On radiation stability analysis with high particle intensity of Uranium ions of about 6 x 10{sup 8} ppp, a stable performance in light output and image reproduction was documented from Al

  2. The location and nature of general anesthetic binding sites on the active conformation of firefly luciferase; a time resolved photolabeling study.

    Directory of Open Access Journals (Sweden)

    Sivananthaperumal Shanmugasundararaj

    Full Text Available Firefly luciferase is one of the few soluble proteins that is acted upon by a wide variety of general anesthetics and alcohols; they inhibit the ATP-driven production of light. We have used time-resolved photolabeling to locate the binding sites of alcohols during the initial light output, some 200 ms after adding ATP. The photolabel 3-azioctanol inhibited the initial light output with an IC50 of 200 µM, close to its general anesthetic potency. Photoincorporation of [(3H]3-azioctanol into luciferase was saturable but weak. It was enhanced 200 ms after adding ATP but was negligible minutes later. Sequencing of tryptic digests by HPLC-MSMS revealed a similar conformation-dependence for photoincorporation of 3-azioctanol into Glu-313, a residue that lines the bottom of a deep cleft (vestibule whose outer end binds luciferin. An aromatic diazirine analog of benzyl alcohol with broader side chain reactivity reported two sites. First, it photolabeled two residues in the vestibule, Ser-286 and Ile-288, both of which are implicated with Glu-313 in the conformation change accompanying activation. Second, it photolabeled two residues that contact luciferin, Ser-316 and Ser-349. Thus, time resolved photolabeling supports two mechanisms of action. First, an allosteric one, in which anesthetics bind in the vestibule displacing water molecules that are thought to be involved in light output. Second, a competitive one, in which anesthetics bind isosterically with luciferin. This work provides structural evidence that supports the competitive and allosteric actions previously characterized by kinetic studies.

  3. Advanced optical simulation of scintillation detectors in GATE V8.0: first implementation of a reflectance model based on measured data

    Science.gov (United States)

    Stockhoff, Mariele; Jan, Sebastien; Dubois, Albertine; Cherry, Simon R.; Roncali, Emilie

    2017-06-01

    Typical PET detectors are composed of a scintillator coupled to a photodetector that detects scintillation photons produced when high energy gamma photons interact with the crystal. A critical performance factor is the collection efficiency of these scintillation photons, which can be optimized through simulation. Accurate modelling of photon interactions with crystal surfaces is essential in optical simulations, but the existing UNIFIED model in GATE is often inaccurate, especially for rough surfaces. Previously a new approach for modelling surface reflections based on measured surfaces was validated using custom Monte Carlo code. In this work, the LUT Davis model is implemented and validated in GATE and GEANT4, and is made accessible for all users in the nuclear imaging research community. Look-up-tables (LUTs) from various crystal surfaces are calculated based on measured surfaces obtained by atomic force microscopy. The LUTs include photon reflection probabilities and directions depending on incidence angle. We provide LUTs for rough and polished surfaces with different reflectors and coupling media. Validation parameters include light output measured at different depths of interaction in the crystal and photon track lengths, as both parameters are strongly dependent on reflector characteristics and distinguish between models. Results from the GATE/GEANT4 beta version are compared to those from our custom code and experimental data, as well as the UNIFIED model. GATE simulations with the LUT Davis model show average variations in light output of    0.99. Experimental data agree within 9% for relative light output. The new model also simplifies surface definition, as no complex input parameters are needed. The LUT Davis model makes optical simulations for nuclear imaging detectors much more precise, especially for studies with rough crystal surfaces. It will be available in GATE V8.0.

  4. Advanced optical simulation of scintillation detectors in GATE V8.0: first implementation of a reflectance model based on measured data.

    Science.gov (United States)

    Stockhoff, Mariele; Jan, Sebastien; Dubois, Albertine; Cherry, Simon R; Roncali, Emilie

    2017-06-21

    Typical PET detectors are composed of a scintillator coupled to a photodetector that detects scintillation photons produced when high energy gamma photons interact with the crystal. A critical performance factor is the collection efficiency of these scintillation photons, which can be optimized through simulation. Accurate modelling of photon interactions with crystal surfaces is essential in optical simulations, but the existing UNIFIED model in GATE is often inaccurate, especially for rough surfaces. Previously a new approach for modelling surface reflections based on measured surfaces was validated using custom Monte Carlo code. In this work, the LUT Davis model is implemented and validated in GATE and GEANT4, and is made accessible for all users in the nuclear imaging research community. Look-up-tables (LUTs) from various crystal surfaces are calculated based on measured surfaces obtained by atomic force microscopy. The LUTs include photon reflection probabilities and directions depending on incidence angle. We provide LUTs for rough and polished surfaces with different reflectors and coupling media. Validation parameters include light output measured at different depths of interaction in the crystal and photon track lengths, as both parameters are strongly dependent on reflector characteristics and distinguish between models. Results from the GATE/GEANT4 beta version are compared to those from our custom code and experimental data, as well as the UNIFIED model. GATE simulations with the LUT Davis model show average variations in light output of    0.99. Experimental data agree within 9% for relative light output. The new model also simplifies surface definition, as no complex input parameters are needed. The LUT Davis model makes optical simulations for nuclear imaging detectors much more precise, especially for studies with rough crystal surfaces. It will be available in GATE V8.0.

  5. Self-assembly surface modified indium-tin oxide anodes for single-layer light-emitting diodes

    CERN Document Server

    Morgado, J; Charas, A; Matos, M; Alcacer, L; Cacialli, F

    2003-01-01

    We study the effect of indium-tin oxide surface modification by self assembling of highly polar molecules on the performance of single-layer light-emitting diodes (LEDs) fabricated with polyfluorene blends and aluminium cathodes. We find that the efficiency and light-output of such LEDs is comparable to, and sometimes better than, the values obtained for LEDs incorporating a hole injection layer of poly(3,4-ethylene dioxythiophene) doped with polystyrene sulphonic acid. This effect is attributed to the dipole-induced work function modification of indium-tin oxide.

  6. KATANA – A charge-sensitive triggering system for the SπRIT experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lasko, P. [Institute of Nuclear Physics, Polish Academy of Sciences,Kraków (Poland); Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University,Kraków (Poland); Adamczyk, M.; Brzychczyk, J. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University,Kraków (Poland); Hirnyk, P.; Łukasik, J. [Institute of Nuclear Physics, Polish Academy of Sciences,Kraków (Poland); Pawłowski, P., E-mail: piotr.pawlowski@ifj.edu.pl [Institute of Nuclear Physics, Polish Academy of Sciences,Kraków (Poland); Pelczar, K. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University,Kraków (Poland); Snoch, A. [University of Wroclaw, Wrocław (Poland); Sochocka, A.; Sosin, Z. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University,Kraków (Poland); Barney, J. [Department of Physics and Astronomy, Michigan State University, East Lansing (United States); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing (United States); Cerizza, G. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing (United States); Estee, J. [Department of Physics and Astronomy, Michigan State University, East Lansing (United States); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing (United States); Isobe, T. [RIKEN Nishina Center, Wako, Saitama (Japan); Jhang, G. [Department of Physics, Korea University, Seoul (Korea, Republic of); Kaneko, M. [Department of Physics, Kyoto University, Kita-shirakawa, Kyoto (Japan); Kurata-Nishimura, M. [RIKEN Nishina Center, Wako, Saitama (Japan); and others

    2017-06-01

    KATANA - the Krakow Array for Triggering with Amplitude discrimiNAtion - has been built and used as a trigger and veto detector for the SπRIT TPC at RIKEN. Its construction allows operating in magnetic field and providing fast response for ionizing particles, giving an approximate forward multiplicity and charge information. Depending on this information, trigger and veto signals are generated. The article presents performance of the detector and details of its construction. A simple phenomenological parametrization of the number of emitted scintillation photons in plastic scintillator is proposed. The effect of the light output deterioration in the plastic scintillator due to the in-beam irradiation is discussed.

  7. Radiation Hardness Study of CsI(Tl) Crystals for Belle II Calorimeter

    CERN Document Server

    Matvienko, D V; Sedov, E V; Shwartz, B A

    2017-01-01

    The Belle II calorimeter (at least, its barrel part) consists of CsI(Tl) scintillation crystals which have been used at the Belle experiment. We perform the radiation hardness study of some typical Belle crystals and conclude their light output reductions are acceptable for Belle II experiment where the absorption dose can reach 10 krad during the detector operation. CsI(Tl) crystals have high stablity and low maintenance cost and are considered as possible option for the calorimeter of the future Super-Charm-Tau factory (SCT) in Novosibirsk. Our study demonstrates sufficiently high radiation hardness of CsI(Tl) crystals for SCT conditions.

  8. Effective scintillation materials based on solid solutions ZnS1–xTex and perspectives of their application

    Directory of Open Access Journals (Sweden)

    Katrunov K. A.

    2011-04-01

    Full Text Available The optimal technological regime of formation ZnS1–xTex solid solution at spacing 0,0≤х≤0,1 has been determined, and has been shown that fritting in hydrogen atmosphere results in more rapid reaction in comparison to argon due to chemical-thermal etching the ZnO layer out. Further annealing in the inert Ar atmosphere leads to the increase of the light output, to the intensive emission band formation and causes afterglow level reduction and the crystalline lattice rearrangement.

  9. Design rule of nanostructures in light-emitting diodes for complete elimination of total internal reflection.

    Science.gov (United States)

    Son, Jun Ho; Kim, Jong Uk; Song, Yang Hee; Kim, Buem Joon; Ryu, Chul Jong; Lee, Jong-Lam

    2012-05-02

    Cone-shaped nanostructures with controllable side-wall angle are success- fully fabricated with a SiO(2) nanosphere lithography (NSL) etching mask. Vertical LEDs with cone-shaped nanostructures with a 24.1° side-wall angle provide 6% more light output power compared to those using hexagonal pyramids formed by photochemical etching. This achievement is attributed to effective elimination of total internal reflection by angle-controlled nanostructures. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Long-term stability scintillation tiles for LHCb detector

    CERN Document Server

    Grinyov, B V; Khlapova, N P; Lebedev, V N; Melnychuk, S V; Senchyshyn, V G

    2004-01-01

    Accelerated thermal aging tests of materials-UPS-923A, UPS-96G, UPS-96GM and their analogues, SCSN-81 (Kuraray) and BC-408 (Bicron)- were made. A forecast of tile lifetime was made for normal conditions of usage (20% reduction of light output and 50% reduction of the bulk attenuation length (BAL) and technical attenuation length (TAL). Scintillator UPS-96GM has the most long-term stability of parameters- more than 11 yr. BC-408 samples have the minimum lifetime ~7 yr. The long-term stability, calculated by light yield reduction, of UPS-96G, UPS-923A and SCSN-81 is 10, 9 and 8 yr, respectively.

  11. Long-term stability scintillation tiles for LHCb detector

    International Nuclear Information System (INIS)

    Grinyov, B.V.; Khlapova, N.P.; Senchyshyn, V.G.; Lebedev, V.N.; Adadurov, A.F.; Melnychuk, S.V.

    2004-01-01

    Accelerated thermal aging tests of materials - UPS-923A, UPS-96G, UPS-96GM and their analogues, SCSN-81 (Kuraray) and BC-408 (Bicron) - were made. A forecast of tile lifetime was made for normal conditions of usage (20% reduction of light output and 50% reduction of the bulk attenuation length (BAL) and technical attenuation length (TAL). Scintillator UPS-96GM has the most long-term stability of parameters--more than 11 yr. BC-408 samples have the minimum lifetime ∼7 yr. The long-term stability, calculated by light yield reduction, of UPS-96G, UPS-923A and SCSN-81 is 10, 9 and 8 yr, respectively

  12. Cyanoplatinate (II) salts as luminescent materials for scintillation counting

    DEFF Research Database (Denmark)

    Bergsøe, P.; Hansen, P.Gregers; Jacobsen, C.F.

    1962-01-01

    .76). The scintillation efficiencies for α-particle excitation are smaller; in terms of the ratio α/β of relative efficiencies (light output per MeV dissipated) one obtains 0.17. Possible applications of these materials are discussed, and because the abundance of high Z material makes the salts especially attractive...... described, and for two other salts information on the composition was lacking. Many of the salts are colorless and the luminescence is in most cases in the blue region. The measurements include light yield and decay time under excitation with fast electrons. Most of the salts were found to be efficient...

  13. Sub-nanosecond plastic scintillators

    International Nuclear Information System (INIS)

    Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

    1976-01-01

    Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

  14. Cross-correlated imaging of single-mode photonic crystal rod fiber with distributed mode filtering

    DEFF Research Database (Denmark)

    Laurila, Marko; Barankov, Roman; Jørgensen, Mette Marie

    2013-01-01

    Photonic crystal bandgap fibers employing distributed mode filtering design provide near diffraction-limited light outputs, a critical property of fiber-based high-power lasers. Microstructure of the fibers is tailored to achieve single-mode operation at specific wavelength by resonant mode...... identify regimes of resonant coupling between higher-order core modes and cladding band. We demonstrate a passive fiber design in which the higher-order modal content inside the single-mode guiding regime is suppressed by at least 20 dB even for significantly misaligned input-coupling configurations....

  15. A Fiber Detector Radiation Hardness Test

    OpenAIRE

    Baehr, J.; Nahnhauer, R.; Nerreter, S.; Shanidze, R.

    1999-01-01

    An intense 146 MeV/c pion beam was stopped inside a scintillating fiber detector made out of 12 planes with 16 pixels each, where every pixel consists out of 8 times 8 scintillating fibers of 500 mkm diameter dense packed. The detector was irradiated for 52 hours to more than 1 Mrad at its center. Before and directly after the irradiation the detector has been exposed to a particle beam to compare the corresponding light output. This study was continued during the following three months using...

  16. Calibrating the CsI(Tl) detectors of the GARFIELD apparatus

    CERN Document Server

    Abbondanno, U; Casini, G; Cavaletti, R; Cavallaro, S; Chiari, M; D'Agostino, M; Gramegna, F; Lanchais, A; Margagliotti, G V; Mastinu, P F; Milazzo, P M; Moroni, A; Nannini, A; Ordine, A; Vannini, G; Vannucci, L

    2002-01-01

    The energy and charge dependence of the light output of the CsI(Tl) detectors of the GARFIELD apparatus has been investigated for heavy ions with 5<=Z<=16 in the energy range from 2.2 to 8.3 A MeV. The results have been compared to an analytical expression successfully used in previous calibration procedures at higher energies, and a rather good agreement was obtained between measured and calculated quantities. The resulting parameter set was successfully applied to another set of experimental data. The overall result demonstrates the validity of the above mentioned calibration procedure in a wide range of incident ion energies and masses.

  17. Optimized excitation energy transfer in a three-dye luminescent solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Sheldon T.; Lokey, Gretchen E.; Hanes, Melinda S.; McLafferty, Jason B.; Beaumont, Gregg T.; Wittmershaus, Bruce P. [School of Science, Pennsylvania State University: Erie, The Behrend College, Erie, PA 16563-0203 (United States); Shearer, John D.M.; Baseler, Timothy T.; Layhue, Joshua M.; Broussard, Dustin R. [School of Engineering, Pennsylvania State University: Erie, The Behrend College, Erie, PA 16563-1701 (United States); Zhang, Yu-Zhong [Molecular Probes Inc., 4849 Pitchford Ave., Eugene, OR 97402-9165 (United States)

    2007-01-05

    The spectral range of sunlight absorbed by a luminescent solar concentrator (LSC) is increased by using multiple dyes. Absorption, fluorescence, and fluorescence excitation spectra, and relative light output are reported for LSCs made with one, two, or three BODIPY dyes in a thin polymer layer on glass. Losses caused by multiple emission and reabsorption events are minimized by optimizing resonance excitation energy transfer between dyes. Increases in the outputs from the multiple-dye LSCs are directly proportional to increases in the number of photons absorbed. The output of the three-dye LSC is 45-170% higher than those of the single-dye LSCs. (author)

  18. Scintillation properties of Lu sub 2 Si sub 2 O sub 7 :Ce sup 3 sup + , a fast and efficient scintillator crystal

    CERN Document Server

    Pidol, L; Viana, B; Ferrand, B; Dorenbos, P; Haas, J; Eijk, C W E; Virey, E

    2003-01-01

    Cerium doped lutetium pyrosilicate Lu sub 2 Si sub 2 O sub 7 :Ce sup 3 sup + (LPS), a new inorganic scintillator, displays particularly promising performance. This material can be readily pulled from the melt. A high light output (average value: 26 300 ph MeV sup - sup 1), a relatively good energy resolution (9%) and a fast decay time (38 ns) without afterglow make this new scintillator very attractive, in particular for medical imaging. Optical characterizations and scintillation properties of LPS:Ce large single crystals are presented, including timing properties and study of the scintillation yields as a function of incident energy.

  19. Dose rate effects in the radiation damage of the plastic scintillators of the CMS Hadron Endcap Calorimeter

    CERN Document Server

    INSPIRE-00314584

    2016-10-07

    We present measurements of the reduction of light output by plastic scintillators irradiated in the CMS detector during the 8 TeV run of the Large Hadron Collider and show that they indicate a strong dose rate effect. The damage for a given dose is larger for lower dose rate exposures. The results agree with previous measurements of dose rate effects, but are stronger due to the very low dose rates probed. We show that the scaling with dose rate is consistent with that expected from diffusion effects.

  20. Design of Fluorescent Compounds for Scintillation Detection

    Energy Technology Data Exchange (ETDEWEB)

    Pla-Dalmau, Anna [Northern Illinois U.

    1990-01-01

    Plastic scintillation detectors for high energy physics applications require the development of new fluorescent compounds to meet the demands set by the future generation of particle accelerators such as the Superconducting Supercollider (SSe). Plastic scintillators are commonly based on a polymer matrix doped with two fluorescent compounds: the primary dopant and the wavelength shifter. Their main characteristics are fast response time and high quantum efficiency. The exposure to larger radiation doses and demands for larger light output questions their survivability in the future experiments. A new type of plastic scintillator - intrinsic scintillator - has been suggested. It uses a single dopant as primary and wavelength shifter, and should be less susceptible to radiation damage....

  1. Design optimization, manufacture and response measurements for fast-neutron radiography converters made of scintillator and wavelength-shifting fibers

    Science.gov (United States)

    Li, Hang; Wu, Yang; Cao, Chao; Huo, Heyong; Tang, Bin

    2014-10-01

    In order to improve the image quality of fast neutron radiography, a converter made of scintillator and wavelength-shifting fibers has been developed. The appropriate parameters of the converter such as fibers arrangement, distance between fibers are optimized theoretically, and manufacture of the converter are also optimized. Fast neutron radiography experiments by 14 MeV neutrons are used to test this converter and kinds of traditional converters. The experiments' results matched the calculations. The novel converter's resolution is better than 1 mm and the light output is high.

  2. Portable laser synthesizer for high-speed multi-dimensional spectroscopy

    Science.gov (United States)

    Demos, Stavros G [Livermore, CA; Shverdin, Miroslav Y [Sunnyvale, CA; Shirk, Michael D [Brentwood, CA

    2012-05-29

    Portable, field-deployable laser synthesizer devices designed for multi-dimensional spectrometry and time-resolved and/or hyperspectral imaging include a coherent light source which simultaneously produces a very broad, energetic, discrete spectrum spanning through or within the ultraviolet, visible, and near infrared wavelengths. The light output is spectrally resolved and each wavelength is delayed with respect to each other. A probe enables light delivery to a target. For multidimensional spectroscopy applications, the probe can collect the resulting emission and deliver this radiation to a time gated spectrometer for temporal and spectral analysis.

  3. Enhanced light emission in blue light-emitting diodes by multiple Mie scattering from embedded silica nanosphere stacking layers.

    Science.gov (United States)

    Park, Young Jae; Kang, Ji Hye; Kim, Hee Yun; Lysak, Volodymyr V; Chandramohan, S; Ryu, Jae Hyoung; Kim, Hyun Kyu; Han, Nam; Jeong, Hyun; Jeong, Mun Seok; Hong, Chang-Hee

    2011-11-07

    We demonstrate enhanced light emission in blue light-emitting diodes (LEDs) by multiple Mie scattering from embedded silica nanosphere stacking layers (SNSL). A honeycomb cone structure is introduced in the GaN epilayer to confine a maximum number of silica nanospheres (SNs). We found that the light is predominantly directed vertically by scattering and geometrical effect in SNSL embedded LEDs. Consequently, the light output power is enhanced by 2.7 times, which we attribute to the improvement in light extraction efficiency due to the multiple Mie scattering of light from the embedded SNSL. The experimental results are verified by simulation using finite difference time domain method (FDTD).

  4. Polarized scintillator targets

    Science.gov (United States)

    van den Brandt, B.; Bunyatova, E. I.; Hautle, P.; Konter, J. A.; Mango, S.

    2000-05-01

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as "live" polarized targets in nuclear physics experiments.

  5. Polarized scintillator targets

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, B. van den E-mail: vandenbrandt@psi.ch; Bunyatova, E.I.; Hautle, P.; Konter, J.A.; Mango, S

    2000-05-21

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as 'live' polarized targets in nuclear physics experiments.

  6. Vacuum ultraviolet light source utilizing rare gas scintillation amplification sustained by photon positive feedback

    Science.gov (United States)

    Aprile, Elena (Inventor); Chen, Danli (Inventor)

    1995-01-01

    A source of light in the vacuum ultraviolet (VUV) spectral region includes a reflective UV-sensitive photocathode supported in spaced parallel relationship with a mesh electrode within a rare gas at low pressure. A high positive potential applied to the mesh electrode creates an electric field which causes drifting of free electrons occurring between the electrodes and producing continuous VUV light output by electric field-driven scintillation amplification sustained by positive photon feedback mediated by photoemission from the photocathode. In one embodiment the lamp emits a narrow-band continuum peaked at 175 nm.

  7. A PREP Panel, Practice-Based, Evaluation of the Handling of the Kerr Demi-Ultra Light Curing Unit.

    Science.gov (United States)

    Burke, F J Trevor; Crisp, Russell J

    2015-09-01

    This paper describes the handling evaluation (by a group of practice-based researchers, the PREP Panel) of a recently introduced Light Curing Unit (LCU), the Kerr Demi-Ultra, which possesses a number of novel features such as its ultracapacitor power source, and the Light Emitting Diodes (LEDs) which provide the light output being placed close to the tip of the light guide. CPD/CLINICAL RELEVANCE: Testing of new devices and materials with respect to their handling is of importance, given that an easy to handle device should produce better clinical results than one which is difficult to use.

  8. Magnetic fields and scintillator performance

    International Nuclear Information System (INIS)

    Green, D.; Ronzhin, A.; Hagopian, V.

    1995-06-01

    Experimental data have shown that the light output of a scintillator depends on the magnitude of the externally applied magnetic fields, and that this variation can affect the calorimeter calibration and possibly resolution. The goal of the measurements presented here is to study the light yield of scintillators in high magnetic fields in conditions that are similar to those anticipated for the LHC CMS detector. Two independent measurements were performed, the first at Fermilab and the second at the National High Magnetic Field Laboratory at Florida State University

  9. Radiation hardness of WLS fibres for the ATLAS Tile Calorimeter

    CERN Document Server

    David, M; Maio, A

    2007-01-01

    In this document we present the data obtained in the irradiation in a Co-60 source of WLS fibers for the TileCal calorimeter. The optical, mechanical and radiation hardness properties of these fibers were developed in close contact with three producers: Bicron, Kuraray and Pol.Hi.Tech. The results on the degradation of the light output and attenuation length from five irradiations are presented. The fibers were irradiated with a total dose at least 3 times higher than the dose predicted for 10 years of operation of LHC at nominal luminosity.

  10. Self-assembly surface modified indium-tin oxide anodes for single-layer light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Morgado, Jorge [Instituto de Telecomunicacoes and Departamento de Engenharia Quimica, Instituto Superior Tecnico, Avenida Rovisco Pais, P-1049-001 Lisbon (Portugal); Barbagallo, Nunzio [Instituto de Telecomunicacoes and Departamento de Engenharia Quimica, Instituto Superior Tecnico, Avenida Rovisco Pais, P-1049-001 Lisbon (Portugal); Charas, Ana [Instituto de Telecomunicacoes and Departamento de Engenharia Quimica, Instituto Superior Tecnico, Avenida Rovisco Pais, P-1049-001 Lisbon (Portugal); Matos, Manuel [Departamento de Engenharia Quimica, Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro-1, P-1949-001 Lisbon (Portugal); Alcacer, Luis [Instituto de Telecomunicacoes and Departamento de Engenharia Quimica, Instituto Superior Tecnico, Avenida Rovisco Pais, P-1049-001 Lisbon (Portugal); Cacialli, Franco [Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT (United Kingdom)

    2003-03-07

    We study the effect of indium-tin oxide surface modification by self assembling of highly polar molecules on the performance of single-layer light-emitting diodes (LEDs) fabricated with polyfluorene blends and aluminium cathodes. We find that the efficiency and light-output of such LEDs is comparable to, and sometimes better than, the values obtained for LEDs incorporating a hole injection layer of poly(3,4-ethylene dioxythiophene) doped with polystyrene sulphonic acid. This effect is attributed to the dipole-induced work function modification of indium-tin oxide.

  11. Quantum Dots Microstructured Optical Fiber for X-Ray Detection

    Science.gov (United States)

    DeHaven, Stan; Williams, Phillip; Burke, Eric

    2015-01-01

    Microstructured optical fibers containing quantum dots scintillation material comprised of zinc sulfide nanocrystals doped with magnesium sulfide are presented. These quantum dots are applied inside the microstructured optical fibers using capillary action. The x-ray photon counts of these fibers are compared to the output of a collimated CdTe solid state detector over an energy range from 10 to 40 keV. The results of the fiber light output and associated effects of an acrylate coating and the quantum dot application technique are discussed.

  12. Laser driven white light source for BRDF measurement

    DEFF Research Database (Denmark)

    Amdemeskel, Mekbib Wubishet; Thorseth, Anders; Dam-Hansen, Carsten

    2017-01-01

    source (UV-VIS-NIR), spectroradiometer and sample holder stepper motor in a dark UV-protected environment. Here, we introduced a special kind of light source which has a bright, stable, broad spectral range and well collimated light output to give a very good angular resolution. The experimental results...... show how stable and reliable is our light source in terms of spectral power distribution, and in BRDF measurement. Furthermore we have shown that we are able to get a well collimated beam and higher power output using set of off-axis parabolic mirrors...

  13. Fabrication of nano-patterned sapphire substrates and their application to the improvement of the performance of GaN-based LEDs

    International Nuclear Information System (INIS)

    Gao Haiyong; Yan Fawang; Zhang Yang; Li Jinmin; Zeng Yiping; Wang Guohong

    2008-01-01

    Nano-patterned sapphire substrates (NPSSs) were fabricated by a chemical wet etching technology using nano-sized SiO 2 as masks. The NPSS was applied to improve the performance of GaN-based light emitting diodes (LEDs). GaN-based LEDs on NPSSs were grown by metal organic chemical vapour deposition. The characteristics of LEDs grown on NPSSs and conventional planar sapphire substrates were studied. The light output powers of the LEDs fabricated on NPSSs were considerably enhanced compared with that of the conventional LEDs grown on planar sapphire substrates

  14. Sub-nanosecond plastic scintillators

    International Nuclear Information System (INIS)

    Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

    1977-01-01

    Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

  15. An integrated model of scintillator-reflector properties for advanced simulations of optical transport

    Science.gov (United States)

    Roncali, Emilie; Stockhoff, Mariele; Cherry, Simon R.

    2017-06-01

    Accurately modeling the light transport in scintillation detectors is essential to design new detectors for nuclear medicine or high energy physics. Optical models implemented in software such as Geant4 and GATE suffer from important limitations that we addressed by implementing a new approach in which the crystal reflectance was computed from 3D surface measurements. The reflectance was saved in a look-up-table (LUT) then used in Monte Carlo simulation to determine the fate of optical photons. Our previous work using this approach demonstrated excellent agreement with experimental characterization of crystal light output in a limited configuration, i.e. when using no reflector. As scintillators are generally encapsulated in a reflector, it is essential to include the crystal-reflector interface in the LUT. Here we develop a new LUT computation and apply it to several reflector types. A second LUT that contains transmittance data is also saved to enable modeling of optical crosstalk. LUTs have been computed for rough and polished crystals coupled to a Lambertian (e.g. Teflon tape) or a specular reflector (e.g. ESR) using air or optical grease, and the light output was computed using a custom Monte Carlo code. 3  ×  3  ×  20 mm3 lutetium oxyorthosilicate crystals were prepared using these combinations, and the light output was measured experimentally at different irradiation depths. For all reflector and surface finish combinations, the measured and simulated light output showed very good agreement. The behavior of optical photons at the interface crystal-reflector was studied using these simulations, and results highlighted the large difference in optical properties between rough and polished crystals, and Lambertian and specular reflectors. These simulations also showed how the travel path of individual scintillation photons was affected by the reflector and surface finish. The ultimate goal of this work is to implement this model in Geant4 and

  16. Nonlinear behavior of structural and luminescent properties in Gd(NbxTa1-x)O4 mixed crystals

    Science.gov (United States)

    Voloshyna, Olesia; Sidletskiy, Oleg; Spassky, Dmitry; Gerasymov, Iaroslav; Romet, Ivo; Belsky, Andrey

    2018-02-01

    Ceramic samples of gadolinium tantalo-niobate mixed crystals were obtained by the solid-state technique. The dependence of luminescence properties on the Nb/Ta ratio in the Gd(NbxTa1-x)O4 system is studied in the 5-450 K temperature range, including thermostimulated luminescence curves in the series of solid solutions. The relation of nonlinear behavior of light output with x variation to non-homogeneous distribution of Nb and Ta in solid solutions is discussed.

  17. Techniques involved in the preparation of radioluminescent sources with promethium-147 and gaseous tritium radionuclides

    International Nuclear Information System (INIS)

    Seshadri, N.K.; Subramanian, T.K.; Ravi, S.; Mathew, K.M.; Chinnayan, C.

    2001-01-01

    Beta radiation emanating from promethium-147 and gaseous tritium in close proximity with zinc sulphide phosphor will provide self sustained light sources and are used for, nocturnal illumination of liquid crystal display digital watches and clocks, product advertisements, telephone numbers, exit signs etc. In this paper a procedure for activation of zinc sulphide phosphor with promethium-147 and development of gaseous tritium light sources with respect to thickness of phosphor coating and its effect on light output is described. A typical light source was constructed with promethium-147 activated zinc sulphide to find the overall efficiency of conversion of beta energy to visible light. (author)

  18. X-ray intensifying screen visible light detection meter.

    Science.gov (United States)

    McLean, D; Eisenhuth, J; Knight, P; Bui, Q

    1997-06-01

    A light meter has been designed and built for the purpose of measuring the light emitted from an intensifying screen during x-ray irradiation. The meter uses a photodiode detector with a minimal drift amplification system. The meter repeatability was better than 0.5% and was found to be linear. A significant x-ray induced signal was recorded during measurement which needed to be subtracted from readings to deduce the intensification screen light output. The energy response of four screen types was subsequently measured.

  19. Device for removing foreign objects from anatomic organs

    Science.gov (United States)

    Angulo, Earl D. (Inventor)

    1992-01-01

    A device is disclosed for removing foreign objects from anatomic organs such as the ear canal or throat. It has a housing shaped like a flashlight, an electrical power source such as a battery or AC power from a wall socket, and a tip extending from the housing. The tip has at least one wire loop made from a shape-memory-effect alloy, such as Nitinol, switchably connected to the electrical power source such that when electric current flows through the wire loop the wire loop heats up and returns to a previously programmed shape such as a curet or tweezers so as to facilitate removal of the foreign object.

  20. Active gate driving method for reliability improvement of IGBTs via junction temperature swing reduction

    DEFF Research Database (Denmark)

    Luo, Haoze; Iannuzzo, Francesco; Ma, Ke

    2016-01-01

    This paper introduces an advanced gate driver used as thermal swing control method for the reduction of AC load current-related ΔTj in Insulated-Gate Bipolar Transistors (IGBTs). A switchable gate resistor network is applied to the advanced gate driver, so that the switching power losses can...... be changed according to the amplitude of AC current. Accordingly, a closed-loop thermal control method including the functions of root-mean-square calculation and phase analysis is proposed. Hence ΔTj can be reduced by means of changing losses-related gate resistors on the basis of output fundamental...

  1. Flexoelectricity induced increase of critical thickness in epitaxial ferroelectric thin films

    International Nuclear Information System (INIS)

    Zhou Hao; Hong Jiawang; Zhang Yihui; Li Faxin; Pei Yongmao; Fang Daining

    2012-01-01

    Flexoelectricity describes the coupling between polarization and strain/stress gradients in insulating crystals. In this paper, using the Landau-Ginsburg-Devonshire phenomenological approach, we found that flexoelectricity could increase the theoretical critical thickness in epitaxial BaTiO 3 thin films, below which the switchable spontaneous polarization vanishes. This increase is remarkable in tensile films while trivial in compressive films due to the electrostriction caused decrease of potential barrier, which can be easily destroyed by the flexoelectricity, between the ferroelectric state and the paraelectric state in tensile films. In addition, the films are still in a uni-polar state even below the critical thickness due to the flexoelectric effect.

  2. System dynamics with interaction discontinuity

    CERN Document Server

    Luo, Albert C J

    2015-01-01

    This book describes system dynamics with discontinuity caused by system interactions and presents the theory of flow singularity and switchability at the boundary in discontinuous dynamical systems. Based on such a theory, the authors address dynamics and motion mechanism of engineering discontinuous systems due to interaction. Stability and bifurcations of fixed points in nonlinear discrete dynamical systems are presented, and mapping dynamics are developed for analytical predictions of periodic motions in engineering discontinuous dynamical systems. Ultimately, the book provides an alternative way to discuss the periodic and chaotic behaviors in discontinuous dynamical systems.

  3. Impact of conductivity on Lorentzian and Fano resonant high-Q THz metamaterials: Superconductor, metal and perfect electric conductor

    Science.gov (United States)

    Srivastava, Yogesh Kumar; Singh, Ranjan

    2017-11-01

    High temperature superconductors have created exciting opportunities for switchable metamaterial and plasmonic devices operating at terahertz frequencies. In recent times, there have been several demonstrations using superconducting metamaterials, such as thermal, electrical, magnetic, and optical switching. Here, we explore the impact of conductivity on terahertz metamaterial resonators with different resonance line shapes. Lorentzian and Fano line shaped resonators show different levels of enhancement in the quality factor and resonance intensity for metallic, superconductor, and perfect electric conductors, due to the interplay between the radiative and the non-radiative loss mechanisms in a metamaterial array.

  4. Establishing the value of advanced glazings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E; Selkowitz, S.

    1999-01-01

    Numerous glazing technologies are under development worldwide to improve the performance of building facades. High-performance glazings can provide substantial energy and related environmental benefits, but often at greatly increased first cost when compared to conventional design solutions. To increase market viability, we discuss strategies to reduce the actual and owner-perceived costs associated with developing and producing advanced window systems, specifically switchable electrochromic glazings, and we also suggest marketing strategies designed to appeal to early adopter and mainstream purchasers. These strategies may be applicable to a broad range of advanced glazing materials.

  5. Pd-Boron-Catalyzed One Carbon Isomerization of Olefins: Water Assisted Process at Room Temperature.

    Science.gov (United States)

    Ojha, Devi Prasan; Gadde, Karthik; Prabhu, Kandikere Ramaiah

    2017-05-05

    A palladium-boronate/borane-system -catalyzed isomerization of olefins has been uncovered. An efficient catalytic combination of [Pd(OAc) 2 ] 3 -boronate-PCy 3 -enabled olefin isomerization at 80 °C has been investigated. Addition of water to the reaction showed a remarkable improvement and the isomerization occurred at ambient temperature. These catalytic systems function efficiently for the isomerization of functionalized as well as unfunctionalized olefins. The catalytic conditions demonstrate the involvement of both nonhydride and metal-hydride medium and can be switchable with water as an additive.

  6. Electronically controllable spoof localized surface plasmons

    Science.gov (United States)

    Zhou, Yong Jin; Zhang, Chao; Yang, Liu; Xun Xiao, Qian

    2017-10-01

    Electronically controllable multipolar spoof localized surface plasmons (LSPs) are experimentally demonstrated in the microwave frequencies. It has been shown that half integer order LSPs modes exist on the corrugated ring loaded with a slit, which actually arise from the Fabry-Perot-like resonances. By mounting active components across the slit in the corrugated rings, electronic switchability and tunability of spoof LSPs modes have been accomplished. Both simulated and measured results demonstrate efficient dynamic control of the spoof LSPs. These elements may form the basis of highly integrated programmable plasmonic circuits in microwave and terahertz regimes.

  7. Giant optical forces in planar dielectric photonic metamaterials.

    Science.gov (United States)

    Zhang, Jianfa; MacDonald, Kevin F; Zheludev, Nikolay I

    2014-08-15

    We demonstrate that resonant optical forces generated within all-dielectric planar photonic metamaterials at near-infrared illumination wavelengths can be an order of magnitude larger than in corresponding plasmonic metamaterials, reaching levels many tens of times greater than the force resulting from radiation pressure. This is made possible by the dielectric structures' freedom from Joule losses and the consequent ability to sustain Fano-resonances with high quality factors that are unachievable in plasmonic nanostructures. Dielectric nano-optomechanical metamaterials can thus provide a functional platform for a range of novel dynamically controlled and self-adaptive nonlinear, tunable/switchable photonic metamaterials.

  8. Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

    KAUST Repository

    Wappel, Julia

    2016-01-28

    A straightforward synthesis utilizing the ring-opening metathesis polymerization (ROMP) reaction is described for acid-triggered N,O-chelating ruthenium-based pre-catalysts bearing one or two 8-quinolinolate ligands. The innovative pre-catalysts were tested regarding their behavior in ROMP and especially for their use in the synthesis of poly(dicyclopentadiene) (pDCPD). Bearing either the common phosphine leaving ligand in the first and second Grubbs olefin metathesis catalysts, or the Ru–O bond cleavage for the next Hoveyda-type catalysts, this work is a step forward towards the control of polymer functionalization and living or switchable polymerizations.

  9. Tunable electro-optic filter stack

    Energy Technology Data Exchange (ETDEWEB)

    Fontecchio, Adam K.; Shriyan, Sameet K.; Bellingham, Alyssa

    2017-09-05

    A holographic polymer dispersed liquid crystal (HPDLC) tunable filter exhibits switching times of no more than 20 microseconds. The HPDLC tunable filter can be utilized in a variety of applications. An HPDLC tunable filter stack can be utilized in a hyperspectral imaging system capable of spectrally multiplexing hyperspectral imaging data acquired while the hyperspectral imaging system is airborne. HPDLC tunable filter stacks can be utilized in high speed switchable optical shielding systems, for example as a coating for a visor or an aircraft canopy. These HPDLC tunable filter stacks can be fabricated using a spin coating apparatus and associated fabrication methods.

  10. Optical computing, optical memory, and SBIRs at Foster-Miller

    Science.gov (United States)

    Domash, Lawrence H.

    1994-03-01

    A desktop design and manufacturing system for binary diffractive elements, MacBEEP, was developed with the optical researcher in mind. Optical processing systems for specialized tasks such as cellular automation computation and fractal measurement were constructed. A new family of switchable holograms has enabled several applications for control of laser beams in optical memories. New spatial light modulators and optical logic elements have been demonstrated based on a more manufacturable semiconductor technology. Novel synthetic and polymeric nonlinear materials for optical storage are under development in an integrated memory architecture. SBIR programs enable creative contributions from smaller companies, both product oriented and technology oriented, and support advances that might not otherwise be developed.

  11. The X-ray microscopy beamline UE46-PGM2 at BESSY

    International Nuclear Information System (INIS)

    Follath, R.; Schmidt, J. S.; Weigand, M.; Fauth, K.

    2010-01-01

    The Max Planck Institute for Metal Physics in Stuttgart and the Helmholtz Center Berlin operate a soft X-ray microscopy beamline at the storage ring BESSY II. A collimated PGM serves as monochromator for a scanning X-ray microscope and a full field X-ray microscope at the helical undulator UE46. The selection between both instruments is accomplished via two switchable focusing mirrors. The scanning microscope (SM) is based on the ALS STXM microscope and fabricated by the ACCEL company. The full field microscope (FFM) is currently in operation at the U41-SGM beamline and will be relocated to its final location this year.

  12. Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

    Directory of Open Access Journals (Sweden)

    Julia Wappel

    2016-01-01

    Full Text Available A straightforward synthesis utilizing the ring-opening metathesis polymerization (ROMP reaction is described for acid-triggered N,O-chelating ruthenium-based pre-catalysts bearing one or two 8-quinolinolate ligands. The innovative pre-catalysts were tested regarding their behavior in ROMP and especially for their use in the synthesis of poly(dicyclopentadiene (pDCPD. Bearing either the common phosphine leaving ligand in the first and second Grubbs olefin metathesis catalysts, or the Ru–O bond cleavage for the next Hoveyda-type catalysts, this work is a step forward towards the control of polymer functionalization and living or switchable polymerizations.

  13. Electric power distribution and load transfer system

    Science.gov (United States)

    Bradford, Michael P. (Inventor); Parkinson, Gerald W. (Inventor); Grant, Ross M. (Inventor)

    1989-01-01

    A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units.

  14. Light-induced switching in pDTE-FICO 1D photonic structures

    Science.gov (United States)

    Kriegel, Ilka; Scotognella, Francesco

    2018-03-01

    We propose the design of 1D photonic crystals and microcavities in which fluorine-indium codoped cadmium oxide (FICO) nanocrystal based layers and layers of diarylethene-based polyester (pDTE) are alternated or embedded in a microcavity. The irradiation with UV light results in two different behaviours: (i) it dopes the FICO nanocrystals inducing a blue shift of their plasmonic resonances; (ii) it changes the real part of the refractive index of the photochromic pDTE polymer. These two behaviours are combined in the proposed photonic structures and can be useful for switchable filters and cavities for light emission.

  15. Stealth fast photoswitching of negative photochromic naphthalene-bridged phenoxyl-imidazolyl radical complexes.

    Science.gov (United States)

    Mutoh, Katsuya; Kobayashi, Yoichi; Hirao, Yasukazu; Kubo, Takashi; Abe, Jiro

    2016-05-21

    Naphthalene-bridged phenoxyl-imidazolyl radical complex (Np-PIC) is a novel fast switchable negative photochromic compound, which shows the thermal back reaction in the millisecond time scale. Upon UV light irradiation, Np-PIC shows the hypochromic effect in the UVA region due to there being less conjugation in the transient isomer. By replacing the phenoxyl unit with a naphthoxyl unit, the molecular structure has an asymmetric carbon, leading to fast chiroptical switching. This simple molecular design will be a good candidate for the future development of negative photochromic compounds.

  16. Subject Responses to Electrochromic Windows

    Energy Technology Data Exchange (ETDEWEB)

    Clear, Robert; Inkarojrit, Vorapat; Lee, Eleanor

    2006-03-03

    Forty-three subjects worked in a private office with switchable electrochromic windows, manually-operated Venetian blinds, and dimmable fluorescent lights. The electrochromic window had a visible transmittance range of approximately 3-60%. Analysis of subject responses and physical data collected during the work sessions showed that the electrochromic windows reduced the incidence of glare compared to working under a fixed transmittance (60%) condition. Subjects used the Venetian blinds less often and preferred the variable transmittance condition, but used slightly more electric lighting with it than they did when window transmittance was fixed.

  17. Variable wavelength selection devices: Physics and applications

    Science.gov (United States)

    Xianyu, Haiqing

    Variable wavelength selection (VWS) achieved by implementing tunability to wavelength discriminating devices has generated great interest in basic science, applied physics, and technology. This thesis focuses on the underlying physics and application of several novel wavelength discriminating devices. Holographical polymer dispersed liquid crystals (HPDLCs) are switchable volume gratings formed by exposing a photopolymerizable monomer and liquid crystal mixture to interfering monochromatic light beams. An HPDLCs wavelength discriminating ability along with its switchability, allow it to be utilized in VWS devices. A novel mode HPDLC, total internal reflection (TIR) HPDLC, has been developed as a wavelength selective filter. The grating planes in this device are tilted so that the diffracted light experiences total internal reflection at the glass-air interface and is trapped in the cell until it eventually escapes from an edge. A VWS device is demonstrated by stacking TIR HPDLCs operating at different wavelengths. Converging or diverging recording beams are employed to fabricate chirped reflection HPDLCs with a pitch gradient along the designated direction, creating chirped switchable reflection gratings (CSRGs). A pixelated version of the CSRG is developed herein, and a dynamic spectral equalizer is presented by combining the pixelated CSRG with a prism (for wavelength discrimination). A switchable circular to point converter (SCPC), which enables the random selection of the wavelength bands divided by the Fabry-Perot interferometer utilizing the controllable beam steering capability of transmission HPDLCs, is demonstrated. A random optical cross-switch (TIROL) can be created by integrating a Fabry-Perot interferometer with a stack of SCPC units. The in-plane electric field generated by the interdigitated electrodes is utilized to elongate the helical pitch of a cholesteric liquid crystal and thereby induces a red shift of the transmission reflection peak

  18. Voltage control of a magnetization easy axis in piezoelectric/ferromagnetic hybrid films

    International Nuclear Information System (INIS)

    Kim, Sang-Koog; Lee, Jeong-Won; Shin, Sung-Chul; Song, Han Wook; Lee, Chang Ho; No, Kwangsoo

    2003-01-01

    We have established a spontaneous magnetization-axis switching in ferromagnetic films by applying a low voltage to a piezoelectric layer in a newly developed hybrid system comprised of the ferromagnetic and piezoelectric films. The magnetization easy axis along which a spontaneous magnetization is oriented, is readily switchable by a voltage without applying an external magnetic field through both the inverse magnetostrictive and piezoelectric effects of CoPd and lead-zirconate-titanate alloy films, respectively. This challenging work provides a new way into the memory writing as well as storage means of ultrahigh bit densities in nonvolatile magnetic random access memory

  19. Polymer Dispersed Liquid Crystal Displays

    Science.gov (United States)

    Doane, J. William

    The following sections are included: * INTRODUCTION AND HISTORICAL DEVELOPMENT * PDLC MATERIALS PREPARATION * Polymerization induced phase separation (PIPS) * Thermally induced phase separation (TIPS) * Solvent induced phase separation (SIPS) * Encapsulation (NCAP) * RESPONSE VOLTAGE * Dielectric and resistive effects * Radial configuration * Bipolar configuration * Other director configurations * RESPONSE TIME * DISPLAY CONTRAST * Light scattering and index matching * Incorporation of dyes * Contrast measurements * PDLC DISPLAY DEVICES AND INNOVATIONS * Reflective direct view displays * Large-scale, flexible displays * Switchable windows * Projection displays * High definition spatial light modulator * Haze-free PDLC shutters: wide angle view displays * ENVIRONMENTAL STABILITY * ACKNOWLEDGEMENTS * REFERENCES

  20. Ultrafast Optical Modulation of Second- and Third-Harmonic Generation from Cut-Disk-Based Metasurfaces

    KAUST Repository

    Sartorello, Giovanni

    2016-06-06

    We design and fabricate a metasurface composed of gold cut-disk resonators that exhibits a strong coherent nonlinear response. We experimentally demonstrate all-optical modulation of both second- and third-harmonic signals on a subpicosecond time scale. Pump-probe experiments and numerical models show that the observed effects are due to the ultrafast response of the electronic excitations in the metal under external illumination. These effects pave the way for the development of novel active nonlinear metasurfaces with controllable and switchable coherent nonlinear response. © 2016 American Chemical Society.