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Sample records for o2 pulse body

  1. Effect of High Frequency Pulsing on the Interfacial Structure of Anodised Aluminium-TiO2

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Jensen, Flemming; Bordo, Kirill

    2015-01-01

    High frequency anodizing of friction stir processed Al-TiO2 surface composites was investigated. The effect of anodizing parameters on the structure and morphology of the anodic layer including the incorporation of the TiO2 particles into the anodic layer is studied. Anodizing process was carried...... out using a high frequency pulse and pulse reverse pulse technique at a fixed frequency in a sulfuric acid bath. The structure of the composites and the anodized layer was studied using scanning and transmission electron microscopy. The pulse reverse pulse anodizing technique, using a negative...

  2. Annealing of SnO2 thin films by ultra-short laser pulses

    NARCIS (Netherlands)

    Scorticati, D.; Illiberi, A.; Bor, T.; Eijt, S.W.H.; Schut, H.; Römer, G.R.B.E.; Lange, D.F. de; Huis In't Veld, A.J.

    2014-01-01

    Post-deposition annealing by ultra-short laser pulses can modify the optical properties of SnO2 thin films by means of thermal processing. Industrial grade SnO2 films exhibited improved optical properties after picosecond laser irradiation, at the expense of a slightly increased sheet resistance

  3. Positron annihilation in SiO 2-Si studied by a pulsed slow positron beam

    Science.gov (United States)

    Suzuki, R.; Ohdaira, T.; Uedono, A.; Kobayashi, Y.

    2002-06-01

    Positron and positronium (Ps) behavior in SiO 2-Si have been studied by means of positron annihilation lifetime spectroscopy (PALS) and age-momentum correlation (AMOC) spectroscopy with a pulsed slow positron beam. The PALS study of SiO 2-Si samples, which were prepared by a dry-oxygen thermal process, revealed that the positrons implanted in the Si substrate and diffused back to the interface do not contribute to the ortho-Ps long-lived component, and the lifetime spectrum of the interface has at least two components. From the AMOC study, the momentum distribution of the ortho-Ps pick-off annihilation in SiO 2, which shows broader momentum distribution than that of crystalline Si, was found to be almost the same as that of free positron annihilation in SiO 2. A varied interface model was proposed to interpret the results of the metal-oxide-semiconductor (MOS) experiments. The narrow momentum distribution found in the n-type MOS with a negative gate bias voltage could be attributed to Ps formation and rapid spin exchange in the SiO 2-Si interface. We have developed a two-dimensional positron lifetime technique, which measures annihilation time and pulse height of the scintillation gamma-ray detector for each event. Using this technique, the positronium behavior in a porous SiO 2 film, grown by a sputtering method, has been studied.

  4. Multiple diagnosis based on photoplethysmography: hematocrit, SpO2, pulse, and respiration

    Science.gov (United States)

    Yoon, Gilwon; Lee, Jong Y.; Jeon, Kye Jin; Park, Kun-Kook; Yeo, Hyung S.; Hwang, Hyun T.; Kim, Hong S.; Hwang, In-Duk

    2002-09-01

    Photo-plethysmography measures pulsatile blood flow in real-time and non-invasively. One of widely known applications of PPG is the measurement of saturated oxygen in arterial blood(SpO2). In our work, using several wavelengths more than those used in a pulse oximeter, an algorithm and instrument have been developed to measure hematocrit, saturated oxygen, pulse and respiratory rates simultaneously. To predict hematocrit, a dedicated algorithm is developed based on scattering of RBC and a protocol for detecting outlier signals is used to increase accuracy and reliability. Digital filtering techniques are used to extract respiratory rate signals. Utilization of wavelengths under 1000nm and a multi-wavelength LED array chip and digital-oriented electronics enable us to make a compact device. Our preliminary clinical trials show that the achieved percent errors are +/-8.2% for hematocrit when tested with 594 persons, R2 for SpO2 fitting is 0.99985 when tested with a Bi-Tek pulse oximeter simulator and the SpO2 error for in vivo test is +/-2.5% over the range of 75~100%. The error of pulse rates is less than +/-5%. We obtained a positive predictive value of 96% for respiratory rates in qualitative analysis.

  5. Annealing characteristics of SiO2-Si structures after incoherent light pulse processing

    International Nuclear Information System (INIS)

    Sieber, N.; Klabes, R.; Voelskow, M.; Fenske, F.

    1982-01-01

    The behaviour of oxide charges and interface charges in boron implanted and non-implanted SiO 2 -Si structures as well as the electrical activation of the dopants by the action of incoherent light pulses was studied. Depth profiles of electrically active boron ions are presented for different annealing conditions as measured by the pulsed C-V method. It can be concluded that exposure of MOS structures to intense radiation of flash lamps does not increase the fixed charge and the fast state density at the SiO 2 -Si interface if optimal annealing conditions (energy densities) are employed. Low dose boron implanted silicon can be electrically activated without diffusion or segregation of dopants

  6. Purification of water by bipolar pulsed discharge plasma combined with TiO2 catalysis

    International Nuclear Information System (INIS)

    Zhang, Yongrui; Ma, Wenchang; Zhang, Xian; Wang, Liming; Zhang, Ruobing; Guan, Zhicheng

    2013-01-01

    In the process of water treatment by bipolar pulsed discharge plasma, there are not only the chemical effects such as the cold plasma, but also the physical effects such as the optical radiation. The energy of the optical radiation can be used by photocatalyst. Therefore, the effect of the photocatalyst to the degradation of the organic pollutant was investigated using a packed bed reactor by bipolar pulsed discharge in the air-liquid-solid mixture. The nanoparticle TiO 2 photocatalyst was obtained using the sol-gel method and the typical dye solution Indigo Carmine was chosen as the degradation target to test the catalytic effect of the nanoparticle TiO 2 photocatalyst. Experiment results proved that the degradation efficiency of the Indigo Carmine solution was increased by a certain extent with the TiO 2 photocatalyst. It was totally decolorized within 3 minutes by bipolar pulsed discharge in the condition that the peak voltage was 30 kV and the air flow was 1.0 m 3 h −1 .

  7. Structure and properties of (Sr, Ca)CuO2-BaCuO2 superlattices grown by pulsed laser interval deposition

    NARCIS (Netherlands)

    Koster, Gertjan; Verbist, Karen; Rijnders, Augustinus J.H.M.; Rogalla, Horst; van Tendeloo, Gustaav; Blank, David H.A.

    2001-01-01

    We report on the preparation of CuBa2(SrxCa1¿x)nCun¿1Oy compounds by fabrication of (Ba,Sr,Ca)CuO2 superlattices with pulsed laser deposition (PLD). A technique called interval deposition is used to suppress multi-level or island growth resulting in high-quality superlattice structures. Both, the

  8. Particle growth mechanisms in Ag-ZrO2 and Au-ZrO2 granular films obtained by pulsed laser deposition

    International Nuclear Information System (INIS)

    Konstantinovic, Zorica; Muro, Montserrat Garcia del; Varela, Manuel; Batlle, Xavier; Labarta, AmIlcar

    2006-01-01

    Thin films consisting of Ag and Au nanoparticles embedded in amorphous ZrO 2 matrix were grown by pulsed laser deposition in a wide range of metal volume concentrations in the dielectric regime (0.08 Ag Au c (Ag)∼0.28 and x c (Au)∼0.52)

  9. Pulse-driven micro gas sensor fitted with clustered Pd/SnO2 nanoparticles.

    Science.gov (United States)

    Suematsu, Koichi; Shin, Yuka; Ma, Nan; Oyama, Tokiharu; Sasaki, Miyuki; Yuasa, Masayoshi; Kida, Tetsuya; Shimanoe, Kengo

    2015-08-18

    Real-time monitoring of specific gas concentrations with a compact and portable gas sensing device is required to sense potential health risk and danger from toxic gases. For such purposes, we developed an ultrasmall gas sensor device, where a micro sensing film was deposited on a micro heater integrated with electrodes fabricated by the microelectromechanical system (MEMS) technology. The developed device was operated in a pulse-heating mode to significantly reduce the heater power consumption and make the device battery-driven and portable. Using clustered Pd/SnO2 nanoparticles, we succeeded in introducing mesopores ranging from 10 to 30 nm in the micro gas sensing film (area: ϕ 150 μm) to detect large volatile organic compounds (VOCs). The micro sensor showed quick, stable, and high sensor responses to toluene at ppm (parts per million) concentrations at 300 °C even by operating the micro heater in a pulse-heating mode where switch-on and -off cycles were repeated at one-second intervals. The high performance of the micro sensor should result from the creation of efficient diffusion paths decorated with Pd sensitizers by using the clustered Pd/SnO2 nanoparticles. Hence we demonstrate that our pulse-driven micro sensor using nanostructured oxide materials holds promise as a battery-operable, portable gas sensing device.

  10. Pulsed ion-beam induced nucleation and growth of Ge nanocrystals on SiO2

    International Nuclear Information System (INIS)

    Stepina, N. P.; Dvurechenskii, A. V.; Armbrister, V. A.; Kesler, V. G.; Novikov, P. L.; Gutakovskii, A. K.; Kirienko, V. V.; Smagina, Zh. V.; Groetzschel, R.

    2007-01-01

    Pulsed low-energy (200 eV) ion-beam induced nucleation during Ge deposition on thin SiO 2 film was used to form dense homogeneous arrays of Ge nanocrystals. The ion-beam action is shown to stimulate the nucleation of Ge nanocrystals when being applied after thin Ge layer deposition. Temperature and flux variation was used to optimize the nanocrystal size and array density required for memory device. Kinetic Monte Carlo simulation shows that ion impacts open an additional channel of atom displacement from a nanocrystal onto SiO 2 surface. This results both in a decrease in the average nanocrystal size and in an increase in nanocrystal density

  11. Investigation of damage threshold to TiO2 coatings at different laser wavelength and pulse duration

    International Nuclear Information System (INIS)

    Yao Jianke; Fan Zhengxiu; Jin Yunxia; Zhao Yuanan; He Hongbo; Shao Jianda

    2008-01-01

    Laser-induced damages to TiO 2 single layers and TiO 2 /SiO 2 high reflectors at laser wavelength of 1064 nm, 800 nm, 532 nm, and pulse width of 12 ns, 220 ps, 50 fs, 8 ns are investigated. All films are prepared by electron beam evaporation. The relations among microstructure, chemical composition, optical properties and laser-induced damage threshold (LIDT), have been researched. The dependence of damage mechanism on laser wavelength and pulse width is discussed. It is found that from 1064 nm to 532 nm, LIDT is mainly absorption related, which is determined by film's extinction coefficient and stoichiometric defects. The rapid decrease of LIDT at 800 nm is due to the pulse width factor. TiO 2 coatings are mainly thermally by damaged at long pulse (τ ≥ 220 ps). The damage shows ablation feature at 50 fs

  12. Phase transitions in LiCoO2 thin films prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Huang Rong; Hitosugi, Taro; Fisher, Craig A.J.; Ikuhara, Yumi H.; Moriwake, Hiroki; Oki, Hideki; Ikuhara, Yuichi

    2012-01-01

    Highlights: ► Epitaxial LiCoO 2 thin films were formed on the Al 2 O 3 (0 0 0 1) substrate by PLD at room temperature and annealed at 600 °C in air. ► The orientation relationship between film and substrate is revealed. ► Crystalline phases in the RT deposited and annealed thin films are clearly identified. ► Atomic level interface structure indicates an interface reaction during annealing. ► A phase transition mechanism from fully disordered LiCoO 2 to fully ordered LiCoO 2 is proposed. - Abstract: Microstructures of epitaxial LiCoO 2 thin films formed on the (0 0 0 1) surface of sapphire (α-Al 2 O 3 ) substrates by pulsed laser deposition at room temperature and annealed at 600 °C in air were investigated by a combination of selected-area electron diffraction, high-resolution transmission electron microscopy, spherical-aberration-corrected high-angle annular dark-field scanning transmission electron microscopy, and electron energy-loss spectroscopy. As-deposited LiCoO 2 thin films consisted of epitaxial grains of the fully cation-disordered phase (γ) with a cubic rock-salt structure. During annealing, this cubic-structured phase transformed into the fully ordered trigonal (α) phase oriented with its basal plane parallel to the surface of the sapphire substrate. Although overall the film appeared to be a single crystal, a small number of Co 3 O 4 grains were also observed in annealed thin films, indicating that some Li and O had been lost during processing. The atomically sharp interface between the film and substrate also became rougher during annealing, with step defects being formed, suggesting that a localized reaction occurred at the interface.

  13. Damage performance of TiO2/SiO2 thin film components induced by a long-pulsed laser

    International Nuclear Information System (INIS)

    Wang Bin; Dai Gang; Zhang Hongchao; Ni Xiaowu; Shen Zhonghua; Lu Jian

    2011-01-01

    In order to study the long-pulsed laser induced damage performance of optical thin films, damage experiments of TiO 2 /SiO 2 films irradiated by a laser with 1 ms pulse duration and 1064 nm wavelength are performed. In the experiments, the damage threshold of the thin films is measured. The damages are observed to occur in isolated spots, which enlighten the inducement of the defects and impurities originated in the films. The threshold goes down when the laser spot size decreases. But there exists a minimum threshold, which cannot be further reduced by decreasing the laser spot size. Optical microscopy reveals a cone-shaped cavity in the film substrate. Changes of the damaged sizes in film components with laser fluence are also investigated. The results show that the damage efficiency increases with the laser fluence before the shielding effects start to act.

  14. A comparative study on the activity of TiO2 in pulsed plasma under different discharge conditions

    Science.gov (United States)

    Lijuan, DUAN; Nan, JIANG; Na, LU; Kefeng, SHANG; Jie, LI; Yan, WU

    2018-05-01

    In the present study, a combination of pulsed discharge plasma and TiO2 (plasma/TiO2) has been developed in order to study the activity of TiO2 by varying the discharge conditions of pulsed voltage, discharge mode, air flow rate and solution conductivity. Phenol was used as the chemical probe to characterize the activity of TiO2 in a pulsed discharge system. The experimental results showed that the phenol removal efficiency could be improved by about 10% by increasing the applied voltage. The phenol removal efficiency for three discharge modes in the plasma-discharge-alone system was found to be highest in the spark mode, followed by the spark–streamer mode and finally the streamer mode. In the plasma/TiO2 system, the highest catalytic effect of TiO2 was observed in the spark–streamer discharge mode, which may be attributed to the favorable chemical and physical effects from the spark–streamer discharge mode, such as ultraviolet light, O3, H2O2, pyrolysis, shockwaves and high-energy electrons. Meanwhile, the optimal flow rate and conductivity were 0.05 m3 l‑1 and 10 μS cm‑1, respectively. The main phenolic intermediates were hydroquinone, catechol, and p-benzoquinone during the discharge treatment process. A different phenol degradation pathway was observed in the plasma/TiO2 system as compared to plasma alone. Analysis of the reaction intermediates demonstrated that p-benzoquinone reduction was selectively catalyzed on the TiO2 surface. The effective decomposition of phenol constant (D e) increased from 74.11% to 79.16% when TiO2 was added, indicating that higher phenol mineralization was achieved in the plasma/TiO2 system.

  15. Plume-induced stress in pulsed-laser deposited CeO2 films

    International Nuclear Information System (INIS)

    Norton, D.P.; Park, C.; Budai, J.D.; Pennycook, S.J.; Prouteau, C.

    1999-01-01

    Residual compressive stress due to plume-induced energetic particle bombardment in CeO 2 films deposited by pulsed-laser deposition is reported. For laser ablation film growth in low pressures, stresses as high as 2 GPa were observed as determined by substrate curvature and four-circle x-ray diffraction. The amount of stress in the films could be manipulated by controlling the kinetic energies of the ablated species in the plume through gas-phase collisions with an inert background gas. The film stress decreased to near zero for argon background pressures greater than 50 mTorr. At these higher background pressures, the formation of nanoparticles in the deposited film was observed. copyright 1999 American Institute of Physics

  16. Yield of H2O2 in Gas-Liquid Phase with Pulsed DBD

    Science.gov (United States)

    Jiang, Song; Wen, Yiyong; Liu, Kefu

    2014-01-01

    Electric discharge in water can generate a large number of oxidants such as ozone, hydrogen peroxide and hydroxyl radicals. In this paper, a non-thermal plasma processing system was established by means of pulsed dielectric barrier discharge in gas-liquid phase. The electrodes of discharge reactor were staggered. The yield of H2O2 was enhanced after discharge. The effects of discharge time, discharge voltage, frequency, initial pH value, and feed gas were investigated. The concentration of hydrogen peroxide and ozone was measured after discharge. The experimental results were fully analyzed. The chemical reaction equations in water were given as much as possible. At last, the water containing Rhodamine B was tested in this system. The degradation rate came to 94.22% in 30 min.

  17. High speed pulsed laser cutting of LiCoO2 Li-ion battery electrodes

    Science.gov (United States)

    Lutey, Adrian H. A.; Fortunato, Alessandro; Carmignato, Simone; Fiorini, Maurizio

    2017-09-01

    Laser cutting of Li-ion battery electrodes represents an alternative to mechanical blanking that avoids complications associated with tool wear and allows assembly of different cell geometries with a single device. In this study, laser cutting of LiCoO2 Li-ion battery electrodes is performed at up to 5m /s with a 1064nm wavelength nanosecond pulsed fiber laser with a maximum average power of 500W and a repetition rate of up to 2MHz . Minimum average cutting power for cathode and anode multi-layer films is established for 12 parameter groups with velocities over the range 1 - 5m /s , varying laser pulse fluence and overlap. Within the tested parameter range, minimum energy per unit cut length is found to decrease with increasing repetition rate and velocity. SEM analysis of the resulting cut edges reveals visible clearance widths in the range 20 - 50 μm , with cut quality found to improve with velocity due to a reduction in lateral heat conduction losses. Raman line map spectra reveal changes in the cathode at 60 μm from the cut edge, where bands at 486cm-1 and 595cm-1 , corresponding to the Eg and A1g modes of LiCoO2 , are replaced with a single wide band centered at 544cm-1 , and evidence of carbon black is no longer present. No changes in Raman spectra are observed in the anode. The obtained results suggest that further improvements in cutting efficiency and quality could be achieved by increasing the repetition rate above 2MHz , thereby improving ablation efficiency of the metallic conductor layers. The laser source utilized in the present study nonetheless represents an immediately available solution for repeatability and throughput that are superior to mechanical blanking.

  18. Temperature field analysis of single layer TiO2 film components induced by long-pulse and short-pulse lasers.

    Science.gov (United States)

    Wang, Bin; Zhang, Hongchao; Qin, Yuan; Wang, Xi; Ni, Xiaowu; Shen, Zhonghua; Lu, Jian

    2011-07-10

    To study the differences between the damaging of thin film components induced by long-pulse and short-pulse lasers, a model of single layer TiO(2) film components with platinum high-absorptance inclusions was established. The temperature rises of TiO(2) films with inclusions of different sizes and different depths induced by a 1 ms long-pulse and a 10 ns short-pulse lasers were analyzed based on temperature field theory. The results show that there is a radius range of inclusions that corresponds to high temperature rises. Short-pulse lasers are more sensitive to high-absorptance inclusions and long-pulse lasers are more easily damage the substrate. The first-damage decision method is drawn from calculations. © 2011 Optical Society of America

  19. Temperature field analysis of single layer TiO2 film components induced by long-pulse and short-pulse lasers

    International Nuclear Information System (INIS)

    Wang Bin; Zhang Hongchao; Qin Yuan; Wang Xi; Ni Xiaowu; Shen Zhonghua; Lu Jian

    2011-01-01

    To study the differences between the damaging of thin film components induced by long-pulse and short-pulse lasers, a model of single layer TiO 2 film components with platinum high-absorptance inclusions was established. The temperature rises of TiO 2 films with inclusions of different sizes and different depths induced by a 1 ms long-pulse and a 10 ns short-pulse lasers were analyzed based on temperature field theory. The results show that there is a radius range of inclusions that corresponds to high temperature rises. Short-pulse lasers are more sensitive to high-absorptance inclusions and long-pulse lasers are more easily damage the substrate. The first-damage decision method is drawn from calculations.

  20. Synthesis of MnO2-graphene composites with enhanced supercapacitive performance via pulse electrodeposition under supergravity field

    International Nuclear Information System (INIS)

    Liu, Tingting; Shao, Guangjie; Ji, Mingtong; Wang, Guiling

    2014-01-01

    A method of pulse electrodeposition under supergravity field was proposed to synthesize MnO 2 -graphene composites. Supergravity is very efficient for promoting mass transfer and decreasing concentration polarization during the electrodeposition process. The synthesis was conducted on our homemade supergravity equipment. The strength of supergravity field depended on the rotating speed of the ring electrode. 3D flower like MnO 2 spheres composed of nanoflakes were acquired when the rotating speed was 3000 rpm. Graphene nanosheets play as a role of conductive substrates for MnO 2 growing. The composites are evaluated as electrode materials for supercapacitors. Electrochemical results show that the maximum specific capacitance of the MnO 2 -graphene composite is 595.7 F g −1 at a current density of 0.5 A g −1 . In addition, the composite exhibits excellent cycle stability with no capacitance attenuation after 1000 cycles. The approach provides new ideas for developing supercapacitor electrode materials with high performance. - Graphical abstract: 3D flower like MnO 2 spheres composed of nanoflakes were acquired at 3000 rpm. - Highlights: • MnO 2 -graphene composites were prepared by pulse electrodeposition under supergravity. • 3D flower like MnO 2 spheres are anchored on the graphene nanosheets. • The MnO 2 -graphene electrode exhibits a specific capacitance of 595.7 F g −1

  1. Water Ice Radiolytic O2, H2, and H2O2 Yields for Any Projectile Species, Energy, or Temperature: A Model for Icy Astrophysical Bodies

    Science.gov (United States)

    Teolis, B. D.; Plainaki, C.; Cassidy, T. A.; Raut, U.

    2017-10-01

    O2, H2, and H2O2 radiolysis from water ice is pervasive on icy astrophysical bodies, but the lack of a self-consistent, quantitative model of the yields of these water products versus irradiation projectile species and energy has been an obstacle to estimating the radiolytic oxidant sources to the surfaces and exospheres of these objects. A major challenge is the wide variation of O2 radiolysis yields between laboratory experiments, ranging over 4 orders of magnitude from 5 × 10-7 to 5 × 10-3 molecules/eV for different particles and energies. We revisit decades of laboratory data to solve this long-standing puzzle, finding an inverse projectile range dependence in the O2 yields, due to preferential O2 formation from an 30 Å thick oxygenated surface layer. Highly penetrating projectile ions and electrons with ranges ≳30 Å are therefore less efficient at producing O2 than slow/heavy ions and low-energy electrons (≲ 400 eV) which deposit most energy near the surface. Unlike O2, the H2O2 yields from penetrating projectiles fall within a comparatively narrow range of (0.1-6) × 10-3 molecules/eV and do not depend on range, suggesting that H2O2 forms deep in the ice uniformly along the projectile track, e.g., by reactions of OH radicals. We develop an analytical model for O2, H2, and H2O2 yields from pure water ice for electrons and singly charged ions of any mass and energy and apply the model to estimate possible O2 source rates on several icy satellites. The yields are upper limits for icy bodies on which surface impurities may be present.

  2. Photoelectrocatalytic properties of Ag nanoparticles loaded TiO2 nanotube arrays prepared by pulse current deposition

    International Nuclear Information System (INIS)

    Xie Kunpeng; Sun Lan; Wang Chenglin; Lai Yuekun; Wang Mengye; Chen Hongbo; Lin Changjian

    2010-01-01

    A pulse current deposition technique was adopted to construct highly dispersed Ag nanoparticles on TiO 2 nanotube arrays which were prepared by the electrochemical anodization. The morphology, crystallinity, elemental composition, and UV-vis absorption of Ag/TiO 2 nanotube arrays were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and diffuse reflectance spectra (DRS). In particular, the photoelectrochemical properties and photoelectrocatalytic activity under UV light irradiation and the photocatalytic activity under visible light irradiation for newly synthesized Ag/TiO 2 nanotube arrays were investigated. The maximum incident photon to charge carrier efficiency (IPCE) value of Ag/TiO 2 nanotube arrays was 51%, much higher than that of pure TiO 2 nanotube arrays. Ag/TiO 2 nanotube arrays exhibited higher photocatalytic activities than the pure TiO 2 nanotube arrays under both UV and visible light irradiation. The photoelectrocatalytic activity of Ag/TiO 2 nanotube arrays under UV light irradiation was 1.6-fold enhancement compared with pure TiO 2 nanotube arrays. This approach can be used in synthesizing various metal-loaded nanotube arrays materials.

  3. Reactions of H2O3 in the pulse-irradiated Fe(II)-O2 system

    DEFF Research Database (Denmark)

    Sehested, Knud; Bjergbakke, Erling; Lang Rasmussen, O.

    1969-01-01

    G(Fe(III)] is measured in pulse-irradiated O2-saturated solutions of 20 to 160 μMFe(II), at the p H's 0.46, 1.51, and 2.74 H2SO4 and HClO4 and with dose rates between 1 and 8 krad/1 μsec pulse. Based on homogeneous kinetics, the results are interpreted by a system of 18 reactions. The formation...

  4. Removal Enhancement of Basic Blue 41 BY RGO-TiO2 Nanocomposite Synthesized Using Pulsed Laser

    Science.gov (United States)

    Ghasemi, Fatemeh; Kimiagar, Salimeh; Shahbazi, Mozhgan; Vojoudi, Hossein

    Graphene oxide (GO) and GO-TiO2 nanocomposite was produced then reduced under pulse laser irradiation (RGO-TiO2). Basic blue 41 (bb41) dye was removed from aqueous solutions by using RGO-TiO2 nanocomposites. The UV-Vis absorption and FTIR analysis were utilized to confirm the reduction of GO-TiO2 to RGO-TiO2. The results showed complete reduction of GO. X-ray diffraction (XRD), Raman spectra and scanning electron microscopy (SEM) analysis were applied to approve the RGO-TiO2 nanocomposite structure. The effect of pH on the bb41 removal by RGO-TiO2 was studied varying the pH from 1 to 11. The optimum pH and adsorbent dosage were found to be 9 and 0.2g/L with 98% efficiency, respectively. The calculated coefficients demonstrated that the Langmuir model was fixed to the experimental data. The results indicated that RGO-TiO2 could be engaged as an exceptional sorbent to remove bb41 dye which is in aqueous solution.

  5. Enhanced dielectric properties of ZrO2 thin films prepared in nitrogen ambient by pulsed laser deposition

    International Nuclear Information System (INIS)

    Zhu, J; Li, T L; Pan, B; Zhou, L; Liu, Z G

    2003-01-01

    ZrO 2 thin films were fabricated in O 2 ambient and in N 2 ambient by pulsed laser deposition (PLD), respectively. X-ray diffraction revealed that films prepared at 400 deg. C remained amorphous. The dielectric properties of amorphous ZrO 2 films were investigated by measuring the capacitance-frequency characteristics of Pt/ZrO 2 /Pt capacitor structures. The dielectric constant of the films deposited in N 2 ambient was larger than that of the films deposited in O 2 ambient. The dielectric loss was lower for films prepared in N 2 ambient. Atom force microscopy investigation indicated that films deposited in N 2 ambient had smoother surface than films deposited in O 2 ambient. Capacitance-voltage and current-voltage characteristics were studied. The equivalent oxide thickness (EOT) of films with 6.6 nm physical thickness deposited in N 2 ambient is lower than that of films deposited in O 2 ambient. An EOT of 1.38 nm for the film deposited in N 2 ambient was obtained, while the leakage current density was 94.6 mA cm -2 . Therefore, ZrO 2 thins deposited in N 2 ambient have enhanced dielectric properties due to the incorporation of nitrogen which leads to the formation of Zr-doped nitride interfacial layer, and is suggested to be a potential material for alternative high-k (high dielectric constant) gate dielectric applications

  6. Continuous Synthesis of Ag/TiO2 Nanoparticles with Enhanced Photocatalytic Activity by Pulsed Laser Ablation

    Directory of Open Access Journals (Sweden)

    Rui Zhou

    2017-01-01

    Full Text Available A facile and environmental friendly synthesis strategy based on pulsed laser ablation has been developed for potential mass production of Ag-loaded TiO2 (Ag/TiO2 nanoparticles. By sequentially irradiating titanium and silver target substrates, respectively, with the same 1064 nm 100 ns fiber laser, Ag/TiO2 particles can be fabricated. A postannealing process leads to the crystallization of TiO2 to anatase phase with high photocatalytic activity. The phase composition, microstructure, and surface state of the elaborated Ag/TiO2 are characterized by X-ray diffraction (XRD, energy dispersive X-ray (EDX, field emission scanning electron microscope (FESEM, transmission electron microscope (TEM, and X-ray photoelectron spectroscopy (XPS techniques. The results suggest that the presence of silver clusters deposited on the surface of TiO2 nanoparticles. The nanostructure is formed through laser interaction with materials. Photocatalytic activity evaluation shows that silver clusters could significantly enhance the photocatalytic activity of TiO2 in degradation of methylene blue (MB under UV light irradiation, which is attributed to the efficient electron traps by Ag clusters. Our developed Ag/TiO2 nanoparticles synthesized via a straightforward, continuous, and green pathway could have great potential applications in photocatalysis.

  7. Suppression of suprathermal ions from a colloidal microjet target containing SnO2 nanoparticles by using double laser pulses

    International Nuclear Information System (INIS)

    Higashiguchi, Takeshi; Kaku, Masanori; Katto, Masahito; Kubodera, Shoichi

    2007-01-01

    We have demonstrated suppression of suprathermal ions from a colloidal microjet target plasma containing tin-dioxide (SnO 2 ) nanoparticles irradiated by double laser pulses. We observed a significant decrease of the tin and oxygen ion signals in the charged-state-separated energy spectra when double laser pulses were irradiated. The peak energy of the singly ionized tin ions decreased from 9 to 3 keV when a preplasma was produced. The decrease in the ion energy, considered as debris suppression, is attributed to the interaction between an expanding low-density preplasma and a main laser pulse

  8. Suppression of suprathermal ions from a colloidal microjet target containing SnO2 nanoparticles by using double laser pulses

    Science.gov (United States)

    Higashiguchi, Takeshi; Kaku, Masanori; Katto, Masahito; Kubodera, Shoichi

    2007-10-01

    We have demonstrated suppression of suprathermal ions from a colloidal microjet target plasma containing tin-dioxide (SnO2) nanoparticles irradiated by double laser pulses. We observed a significant decrease of the tin and oxygen ion signals in the charged-state-separated energy spectra when double laser pulses were irradiated. The peak energy of the singly ionized tin ions decreased from 9to3keV when a preplasma was produced. The decrease in the ion energy, considered as debris suppression, is attributed to the interaction between an expanding low-density preplasma and a main laser pulse.

  9. Effects of TiO2 nanoparticles on nutrition metabolism in silkworm fat body

    Directory of Open Access Journals (Sweden)

    J. H. Tian

    2016-06-01

    Full Text Available Silkworm (Bombyx mori is an important economic insect with a fat body that plays a crucial role in the storage and transfer of nutrients. It is also known that TiO2 nanoparticles (NPs can improve feed efficiency and promote silk protein synthesis in the silkworm. In this study, we profiled gene expression in the silkworm fat body after TiO2 NP treatment, validated the major RNA-seq findings, and determined the contents of trehalose and triglyceride, the activity of lipase, and the amount of total proteins. RNA-seq analysis revealed that TiO2 NP treatment caused significant expression changes in 341 genes (P≤0.01, 138 of which were upregulated while the other 203 were downregulated. The expression levels of two target genes in the insulin signaling pathway and two protein metabolism-related target genes, three lipid metabolism-associated target genes, two carbohydrate metabolism related target genes and expression levels of seven heat shock protein genes were increased, and that of threonine dehydratase gene and fatty acid transport protein gene were decreased. The RNA-seq results of 16 genes were validated by quantitative real-time PCR. The lipase activity, content of trehalose, and amount of total proteins were elevated by 3.86-fold, 1.34-fold, and 1.21-fold, respectively, and the content of triglyceride was decreased by 0.94-fold after TiO2 NP treatment. These results indicated that TiO2 NPs activated the insulin signaling pathway, promoted the metabolism of protein, fat, and carbohydrate, and improved nutrition metabolism. Our study provides new support for the understanding of the beneficial effect of TiO2 NPs on silkworm nutrient metabolism.

  10. F-doped SnO2 thin films grown on flexible substrates at low temperatures by pulsed laser deposition

    International Nuclear Information System (INIS)

    Kim, H.; Auyeung, R.C.Y.; Pique, A.

    2011-01-01

    Fluorine-doped tin oxide (SnO 2 :F) films were deposited on polyethersulfone plastic substrates by pulsed laser deposition. The electrical and optical properties of the SnO 2 :F films were investigated as a function of deposition conditions such as substrate temperature and oxygen partial pressure during deposition. High quality SnO 2 :F films were achieved under an optimum oxygen pressure range (7.4-8 Pa) at relatively low growth temperatures (25-150 deg. C). As-deposited films exhibited low electrical resistivities of 1-7 mΩ-cm, high optical transmittance of 80-90% in the visible range, and optical band-gap energies of 3.87-3.96 eV. Atomic force microscopy measurements revealed a reduced root mean square surface roughness of the SnO 2 :F films compared to that of the bare substrates indicating planarization of the underlying substrate.

  11. Uniform thin films of TiO2 nanoparticles deposited by matrix-assisted pulsed laser evaporation

    International Nuclear Information System (INIS)

    Caricato, A.P.; Manera, M.G.; Martino, M.; Rella, R.; Romano, F.; Spadavecchia, J.; Tunno, T.; Valerini, D.

    2007-01-01

    We report morphological and optical properties of a colloidal TiO 2 nanoparticle film, deposited on a quartz substrate by using the Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique. Atomic Force Microscopy demonstrated that a good uniformity of the deposition can be obtained. The presence of agglomerates with dimensions of about 1 μm in size was noticed. Form UV-vis transmission spectra, recorded in the 200-800 nm range, the optical constants and the energy gap were determined besides the film thickness. The optical constants resulted in agreement with the values reported in literature for TiO 2 nanoparticle thin films

  12. Rapid fabrication of mesoporous TiO2 thin films by pulsed fibre laser for dye sensitized solar cells

    Science.gov (United States)

    Hadi, Aseel; Alhabradi, Mansour; Chen, Qian; Liu, Hong; Guo, Wei; Curioni, Michele; Cernik, Robert; Liu, Zhu

    2018-01-01

    In this paper we demonstrate for the first time that a fibre laser with a wavelength of 1070 nm and a pulse width of milliseconds can be applied to generate mesoporous nanocrystalline (nc) TiO2 thin films on ITO coated glass in ambient atmosphere, by complete vaporisation of organic binder and inter-connection of TiO2 nanoparticles, without thermally damaging the ITO layer and the glass substrate. The fabrication of the mesoporous TiO2 thin films was achieved by stationary laser beam irradiation of 1 min. The dye sensitized solar cell (DSSC) with the laser-sintered TiO2 photoanode reached higher power conversion efficiency (PCE) of 3.20% for the TiO2 film thickness of 6 μm compared with 2.99% for the furnace-sintered. Electrochemical impedance spectroscopy studies revealed that the laser sintering under the optimised condition effectively decreased charge transfer resistance and increased electron lifetime of the TiO2 thin films. The use of the fibre laser with over 40% wall-plug efficiency offers an economically-feasible, industrial viable solution to the major challenge of rapid fabrication of large scale, mass production of mesoporous metal oxide thin film based solar energy systems, potentially for perovskite and monolithic tandem solar cells, in the future.

  13. Deposition of Au/TiO2 film by pulsed laser

    International Nuclear Information System (INIS)

    Zhao Chongjun; Zhao Quanzhong; Zhao Qitao; Qiu Jianrong; Zhu Congshan

    2006-01-01

    Au nanoparticles, which were photoreduced by a Nd:YAG laser in HAuCl 4 solution containing TiO 2 colloid and accompanied by the TiO 2 particles, were deposited on the substrate surface. The film consisting of Au/TiO 2 particles was characterized by the absorption spectra, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The adhesion between the film and substrate was evaluated by using adhesive tape test. It was found that the presence of TiO 2 dramatically enhanced the adhesion strength between the film and the substrate, as well as the deposition rate of film. The mechanism for the deposition of Au/TiO 2 film was also discussed

  14. A photocatalytic approach in micro arc oxidation of WO3-TiO2 nano porous semiconductors under pulse current

    International Nuclear Information System (INIS)

    Bayati, M.R.; Golestani-Fard, F.; Moshfegh, A.Z.; Molaei, R.

    2011-01-01

    Graphical abstract: WO3-TiO2 layers were fabricated via microarc oxidation process and effect of the electrical current type on their photocatalytic performance under UV and visible illuminations was investigated. Highlights: → WO3-TiO2 layers were grown by MAO under pulse current for the first time. → Effect of the frequency and duty cycle on properties of the layers was studied. → A correlation between catalytic performance and growth conditions was proposed. - Abstract: Since ultraviolet (UV) irradiation cannot be applied for a long time in practical applications, it is necessary to develop a narrow band gap photocatalyst to decompose environmental pollutants under visible irradiation. In this research, (WO 3 ) x -(TiO 2 ) 1-x nano-porous layers were fabricated by micro arc oxidation (MAO) and influence of the electrical current type on their physical and chemical properties was investigated. Morphological studies, performed by SEM technique, revealed that pore size and roughness decreased with the frequency and increased with the duty cycle. The pulse-grown layers had a finer structure when compared to those fabricated under direct current. XRD and XPS results showed that the layers consisted of anatase, rutile, and tungsten oxide phases. Applying pulse current resulted in higher anatase relative contents. Band gap energies of the MAO-grown TiO 2 and WO 3 -TiO 2 layers were respectively measured as 3.14 and 2.96 eV. The layers fabricated under pulse current exhibited higher photoactivity under ultraviolet and visible illuminations as compared to the layers grown under direct current. Methylene blue (MB) was used as a model material to examine photocatalytic performance of the layers. Maximum MB-photodegradation reaction rate constants over the pulse-synthesized WO 3 -TiO 2 layers were measured as 0.0269 and 0.0129 min -1 for ultraviolet and visible irradiations. For layers grown under direct current, the rate constants were lower, i.e. 0.0228 and 0

  15. Electrochemical preparation of MnO2 nanobelts through pulse base-electrogeneration and evaluation of their electrochemical performance

    Science.gov (United States)

    Aghazadeh, Mustafa; Maragheh, Mohammad Ghannadi; Ganjali, Mohammad Reza; Norouzi, Parviz; Faridbod, Farnoush

    2016-02-01

    Cathodic electrodeposition of MnO2 from a nitrate solution, via pulsed base (OH-) electrogeneration was performed for the first time. The deposition experiments were performed in a pulse current mode in typical on-times and off-times (i.e. ton = 1 s and toff = 1 s) with a peak current density of 2 mA cm-2 (Ia = 2 mA cm-2). The structural characterizations conducted by XRD and FTIR techniques revealed that the prepared MnO2 is composed of both α and γ phases. Morphological observation by SEM and TEM showed that the prepared MnO2 is made up of nanobelts with uniform shapes (an average diameter and length of 50 nm and 1 μm, respectively). Further electrochemical measurements by cyclic voltammetry and charge-discharge techniques revealed that the prepared MnO2 nanostructures have excellent capacitive behaviors, like a specific capacitance of 235.5 F g-1 and capacity retention of 91.3% after 1000 cycling at the scan rate of 25 mV s-1.

  16. TiO2 nanoparticle thin film deposition by matrix assisted pulsed laser evaporation for sensing applications

    International Nuclear Information System (INIS)

    Caricato, A.P.; Capone, S.; Ciccarella, G.; Martino, M.; Rella, R.; Romano, F.; Spadavecchia, J.; Taurino, A.; Tunno, T.; Valerini, D.

    2007-01-01

    The MAPLE technique has been used for the deposition of nanostructured titania (TiO 2 ) nanoparticles thin films to be used for gas sensors applications. An aqueous solution of TiO 2 nanoparticles, synthesised by a novel chemical route, was frozen at liquid nitrogen temperature and irradiated with a pulsed ArF excimer laser in a vacuum chamber. A uniform distribution of TiO 2 nanoparticles with an average size of about 10 nm was deposited on Si and interdigitated Al 2 O 3 substrates as demonstrated by high resolution scanning electron microscopy-field emission gun inspection (SEM-FEG). Energy dispersive X-ray (EDX) analysis revealed the presence of only the titanium and oxygen signals and FTIR (Fourier transform infra-red) revealed the TiO 2 characteristic composition and bond. A comparison with a spin coated thin film obtained from the same solution of TiO 2 nanoparticles is reported. The sensing properties of the films deposited on interdigitated substrates were investigated, too

  17. Phenol degradation by TiO2 photocatalysts combined with different pulsed discharge systems.

    Science.gov (United States)

    Zhang, Yi; Lu, Jiani; Wang, Xiaoping; Xin, Qing; Cong, Yanqing; Wang, Qi; Li, Chunjuan

    2013-11-01

    Films of TiO2 nanotubes distributed over the inner surface of a discharge reactor cylinder (CTD) or adhered to a stainless steel electrode surface (PTD) in a discharge reactor were compared with a single-discharge (SD) system to investigate their efficiencies in phenol degradation. Morphology studies indicated that the TiO2 film was destroyed in the PTD system, but that there was no change in the CTD system after discharge. X-ray diffraction results revealed that the anatase phase of the original sample was preserved in the CTD system, but that an anatase-to-rutile phase transformation occurred in the PTD system after discharge. The highest efficiencies of phenol degradation and total organic carbon (TOC) mineralization were observed in the CTD system, and there was no decrease in phenol degradation efficiency upon reuse of a TiO2 film, indicating high catalysis activity and stability of the TiO2 photocatalysts in the combined treatment. TiO2 photocatalysts favored the formation of hydrogen peroxide and disfavored the formation of ozone. A greater degree of oxidation of intermediates and higher energy efficiency in phenol oxidation were observed with the TiO2-plasma systems, especially in the CTD system, compared to those with the SD system. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. One-Pot Hybrid SnO2 /Poly(methyl methacrylate) Nanocomposite Formation through Pulsed Laser Irradiation.

    Science.gov (United States)

    Caputo, Gianvito; Scarpellini, Alice; Palazon, Francisco; Athanassiou, Athanassia; Fragouli, Despina

    2017-06-20

    The localized in situ formation of tin dioxide (SnO 2 ) nanoparticles embedded in poly(methyl methacrylate) (PMMA) films is presented. This is achieved by the photoinduced conversion of the tin acetate precursor included in polymeric films, through controlled UV or visible pulsed laser irradiation at λ=355 and 532 nm, respectively. The evolution of the formation of nanoparticles is followed by UV/Vis spectroscopy and shows that their growth is affected in different ways by the laser pulses at the two applied wavelengths. This, in combination with electron microscopy analysis, reveals that, depending on the irradiation wavelength, the size of the nanoparticles in the final nanocomposites differs. This difference is attributed to distinct mechanistic pathways that lead to the synthesis of small nanoparticles (from 1.5 to 4.5 nm) at λ=355 nm, whereas bigger ones (from 5 to 16 nm) are formed at λ=532 nm. At the same time, structural studies with both X-ray and electron diffraction measurements demonstrate the crystallinity of SnO 2 nanoparticles in both cases, whereas XPS analysis confirms the light-induced oxidation of tin acetate into SnO 2 . Taken all together, it is demonstrated that the pulsed laser irradiation at λ=355 and 532 nm leads to the formation of SnO 2 nanoparticles with defined features highly dispersed in PMMA solid matrices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Synthesis of ZnTe nanowires onto TiO2 nanotubular arrays by pulse-reverse electrodeposition

    International Nuclear Information System (INIS)

    Gandhi, T.; Raja, K.S.; Misra, M.

    2009-01-01

    Growth of ZnTe nanowires using a pulse-reverse electrodeposition technique from a non-aqueous solution is reported. ZnTe nanowires were grown on to an ordered nanotubular TiO 2 template in a propylene carbonate solution at 130 o C inside a controlled atmosphere glove box. The pulse-reverse electro deposition process consisted of a cathodic pulse at - 0.62 V and an anodic pulse at 0.75 V Vs Zn 2+ /Zn. Stoichiometry growth of crystalline ZnTe nanowires was observed in the as-deposited condition. The anodic pulse cycle of the pulse-reverse electrodeposition process presumably introduced zinc vacancies as deep level acceptors at an energy level of E v + 0.47 eV. The resultant ZnTe nanowires showed p-type semiconductivity with a resistivity of 7.8 x 10 4 Ω cm and a charge carrier density of 1.67 x 10 14 cm -3 . Annihilation of the defects occurred upon thermal annealing that resulted in marginal decrease in the defect density.

  20. Pulsed laser deposition of {CeO_2} and {Ce_{1-x}M_xO_2} (M = La, Zr): Application to insulating barrier in cuprate heterostructures

    Science.gov (United States)

    Berger, S.; Contour, J.-P.; Drouet, M.; Durand, O.; Khodan, A.; Michel, D.; Régi, F.-X.

    1998-03-01

    SrTiO_3 had been often tentatively used as an insulating barrier for HT superconductor/insulator heterostructures. Unfortunately, the deposition of SrTiO_3 on the YBa_2Cu_3O_7 inverse interface results in a poor epitaxial regrowth producing a high roughness dislocated titanate layer. Taking into account the good matching with YBa_2Cu_3O_7 and LaAlO_3, CeO_2 and Ce_{1-x}M_xO_2 (M = La, Zr), epitaxial layers were grown by pulsed laser deposition on LaAlO_3 substrates and introduced into YBa_2Cu_3O_7 based heterostructures as insulating barrier. After adjusting the growth parameters from RHEED oscillations, epitaxial growth is achieved, the oxide crystal axes being rotated by 45^circ from those of the substrate. The surface roughness of 250 nm thick films is very low with a rms value lower than 0.5 nm over 1;μ m^2. The YBa_2Cu_3O_7 layers of a YBa_2Cu_3O_7/CeO_2 /YBa_2Cu_3O_7 heterostructures grown using these optimized parameters show an independent resistive transition, when the thickness is larger than 25 nm, respectively at T_c_1 = 89.6;K and T_c_2 = 91.4;{K}. SrTiO3 est souvent utilisé comme barrière isolante dans des hétérostructures SIS de cuprates supraconducteurs, cependant les défauts générés lors de la croissance de ce titanate sur l'interface inverse de YBa2Cu3O7 conduisent à un matériau dont la qualité cristalline et les propriétés physiques sont médiocres. L'oxyde de cérium CeO2 est également une barrière isolante potentielle intéressante pour ces structures SIS basées sur YBa2Cu3O7 car cet oxyde cubique (a = 0,5411 nm, asqrt{2}/2 = 0,3825 nm) qui est peu désaccordé par rapport au plan ab du cuprate (Δ a/a = - 0,18 %, Δ b/a = 1,6 %) présente de plus un coefficient de dilatation thermique (10,6 × 10^{-6 circ}C^{-1}) très voisin de celui de YBa2Cu3O7 (13 × 10^{-6 circ}C^{-1}). Nous avons donc étudié l'épitaxie de CeO2 et des oxydes de type Ce{1-x}MxO2 (M = La, Zr) en ablation laser pulsée afin de définir des conditions de

  1. Structural, morphological and local electric properties of TiO2 thin films grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Gyoergy, E; Pino, A Perez del; Sauthier, G; Figueras, A; Alsina, F; Pascual, J

    2007-01-01

    Titanium dioxide (TiO 2 ) thin films were synthesized on (1 0 0) Si substrates by reactive pulsed laser deposition (PLD) technique. A frequency quadrupled Nd : YAG (λ = 266 nm, τ FWHM ≅ 5 ns, ν = 10 Hz) laser source was used for the irradiations of metallic Ti targets. The experiments were performed in controlled oxygen atmosphere. Crystallinity, surface morphology and local electric properties of the obtained oxide thin films were investigated by x-ray diffractometry, micro-Raman spectroscopy and current sensing atomic force microscopy. An inter-relation was found between the surface morphology, the crystalline structure and the nano-scale electric properties which open the possibility of synthesizing by the PLD technique TiO 2 thin films with tunable functional properties for future applications such as photocatalysts, gas sensors or solar energy converters

  2. Multifractal spectra of scanning electron microscope images of SnO2 thin films prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Chen, Z.W.; Lai, J.K.L.; Shek, C.H.

    2005-01-01

    The concept of fractal geometry has proved useful in describing structures and processes in experimental systems. In this Letter, the surface topographies of SnO 2 thin films prepared by pulsed laser deposition for various substrate temperatures were measured by scanning electron microscope (SEM). Multifractal spectra f(α) show that the higher the substrate temperature, the wider the spectrum, and the larger the Δf(Δf=f(α min )-f(α max )). It is apparent that the nonuniformity of the height distribution increases with the increasing substrate temperature, and the liquid droplets of SnO 2 thin films are formed on previous thin films. These results show that the SEM images can be characterized by the multifractal spectra

  3. Manipulation of stored charge in anodic aluminium oxide/SiO2 dielectric stacks by the use of pulsed anodisation

    International Nuclear Information System (INIS)

    Lu, Zhong; Ouyang, Zi; Grant, Nicholas; Wan, Yimao; Yan, Di; Lennon, Alison

    2016-01-01

    Graphical abstract: - Highlights: • Pulse anodisation was used to grow AAO layers with controllable stored charge. • Stored charge density ranging from −5.2 × 10 11 to 2.5 × 10 12 q/cm 2 was demonstrated. • Enhancement in surface passivation was demonstrated with charge management. • Annealing significantly reduces the positive stored charge and the interface defect. - Abstract: A method of fabricating anodic aluminium oxide (AAO) with the capability of manipulating its stored charge is reported. This method involves the use of a pulsed current source to anodise aluminium layers instead of the typically used constant current/voltage source, with the test structures experiencing positive and negative cycles periodically. By tuning the positive cycle percentage, it is demonstrated that the effective stored charge density can be manipulated in a range from −5.2 × 10 11 to 2.5 × 10 12 q/cm 2 when the AAO is formed over a 12 nm SiO 2 layer. An investigation of the stored charge distribution in the dielectric stacks indicates a positive fixed charge at the SiO 2 /Si interface, a negative fixed charge at the AAO/SiO 2 interface and a positive bulk charge within the AAO layer. The effective stored charge density and interface states were found to be affected by annealing conditions and it is suggested that oxygen annealing can reduce the bulk positive charge while post-metallisation anneal is most effective in reducing silicon interface defects. Charge manipulation using pulsed anodisation is shown to reduce carrier recombination on boron-diffused silicon surfaces highlighting the potential of the process to be used to tune the electrical properties of dielectric layers so that they can reduce surface recombination on silicon surfaces having different dopant polarity and concentrations.

  4. Changes in body weight and pulse

    DEFF Research Database (Denmark)

    Seimon, R V; Espinoza, D; Finer, N

    2015-01-01

    BACKGROUND/OBJECTIVES: The Sibutramine Cardiovascular OUTcomes (SCOUT) trial showed a significantly increased relative risk of nonfatal cardiovascular events, but not mortality, in overweight and obese subjects receiving long-term sibutramine treatment with diet and exercise. We examined the rela......BACKGROUND/OBJECTIVES: The Sibutramine Cardiovascular OUTcomes (SCOUT) trial showed a significantly increased relative risk of nonfatal cardiovascular events, but not mortality, in overweight and obese subjects receiving long-term sibutramine treatment with diet and exercise. We examined...... the relationship between early changes (both increases and decreases) in pulse rate, and the impact of these changes on subsequent cardiovascular outcome events in both the placebo and sibutramine groups. SUBJECTS/METHODS: 9804 males and females, aged ⩾55 years, with a body mass index of 27-45 kg m(-)(2) were...... included in this current subanalysis of the SCOUT trial. Subjects were required to have a history of cardiovascular disease and/or type 2 diabetes mellitus with at least one cardiovascular risk factor, to assess cardiovascular outcomes. The primary outcome event (POE) was a composite of nonfatal myocardial...

  5. Whole-body distribution and dosimetry of O-(2-[18F]fluoroethyl)-l-tyrosine

    International Nuclear Information System (INIS)

    Pauleit, Dirk; Floeth, Frank; Herzog, Hans; Tellmann, Lutz; Langen, Karl-J.; Hamacher, Kurt; Coenen, Heinz H.; Mueller, Hans-W.

    2003-01-01

    The whole-body distribution of O-(2-[ 18 F]fluoroethyl)-l-tyrosine (FET) was studied in seven patients with brain tumours by positron emission tomography (PET). Based on the IMEDOSE and MIRDOSE procedures, radiation absorbed doses were estimated from whole-body PET scans acquired approximately 70 and 200 min after i.v. injection of 400 MBq FET. After injection of FET, the peak of radioactivity in the blood was observed after 1.5 min, and a plateau of nearly constant radioactivity was reached at 20 min. The whole-body distribution of FET showed the highest activities in the urinary tract. All other organs exhibited only moderate FET uptake (SUV ≤1.6) which remained constant between early and late PET scans. No increased uptake was seen in the bone, the biliary tract or the pancreas. Twenty-two percent of the injected activity was excreted 5 h p.i. (approx. 5.3% ID/h). The highest absorbed dose was found for the urinary bladder wall. The effective dose according to ICRP 60 was 16.5 μSv/MBq for adults, which would lead to an effective dose of 6.1 mSv in a PET study using 370 MBq FET. (orig.)

  6. Whole-body distribution and dosimetry of O-(2-[{sup 18}F]fluoroethyl)-l-tyrosine

    Energy Technology Data Exchange (ETDEWEB)

    Pauleit, Dirk [Clinic of Nuclear Medicine, Heinrich-Heine-University Duesseldorf, Duesseldorf (Germany); Clinic of Nuclear Medicine, Research Center Juelich, P.O. Box 1913, 52425, Juelich (Germany); Floeth, Frank [Department of Neurosurgery, Heinrich-Heine-University Duesseldorf, Duesseldorf (Germany); Herzog, Hans; Tellmann, Lutz; Langen, Karl-J. [Institute of Medicine, Research Center Juelich, Juelich (Germany); Hamacher, Kurt; Coenen, Heinz H. [Institute of Nuclear Chemistry, Research Center Juelich, Juelich (Germany); Mueller, Hans-W. [Clinic of Nuclear Medicine, Heinrich-Heine-University Duesseldorf, Duesseldorf (Germany)

    2003-04-01

    The whole-body distribution of O-(2-[{sup 18}F]fluoroethyl)-l-tyrosine (FET) was studied in seven patients with brain tumours by positron emission tomography (PET). Based on the IMEDOSE and MIRDOSE procedures, radiation absorbed doses were estimated from whole-body PET scans acquired approximately 70 and 200 min after i.v. injection of 400 MBq FET. After injection of FET, the peak of radioactivity in the blood was observed after 1.5 min, and a plateau of nearly constant radioactivity was reached at 20 min. The whole-body distribution of FET showed the highest activities in the urinary tract. All other organs exhibited only moderate FET uptake (SUV {<=}1.6) which remained constant between early and late PET scans. No increased uptake was seen in the bone, the biliary tract or the pancreas. Twenty-two percent of the injected activity was excreted 5 h p.i. (approx. 5.3% ID/h). The highest absorbed dose was found for the urinary bladder wall. The effective dose according to ICRP 60 was 16.5 {mu}Sv/MBq for adults, which would lead to an effective dose of 6.1 mSv in a PET study using 370 MBq FET. (orig.)

  7. Whole-body distribution and dosimetry of O-(2-[18F]fluoroethyl)-L-tyrosine.

    Science.gov (United States)

    Pauleit, Dirk; Floeth, Frank; Herzog, Hans; Hamacher, Kurt; Tellmann, Lutz; Müller, Hans-W; Coenen, Heinz H; Langen, Karl-J

    2003-04-01

    The whole-body distribution of O-(2-[(18)F]fluoroethyl)- l-tyrosine (FET) was studied in seven patients with brain tumours by positron emission tomography (PET). Based on the IMEDOSE and MIRDOSE procedures, radiation absorbed doses were estimated from whole-body PET scans acquired approximately 70 and 200 min after i.v. injection of 400 MBq FET. After injection of FET, the peak of radioactivity in the blood was observed after 1.5 min, and a plateau of nearly constant radioactivity was reached at 20 min. The whole-body distribution of FET showed the highest activities in the urinary tract. All other organs exhibited only moderate FET uptake (SUV

  8. Growth and characterization of nitrogen-doped TiO2 thin films prepared by reactive pulsed laser deposition

    International Nuclear Information System (INIS)

    Sauthier, G.; Ferrer, F.J.; Figueras, A.; Gyoergy, E.

    2010-01-01

    Nitrogen-doped titanium dioxide (TiO 2 ) thin films were grown on (001) SiO 2 substrates by reactive pulsed laser deposition. A KrF* excimer laser source (λ = 248 nm, τ FWHM ≅ 10 ns, ν = 10 Hz) was used for the irradiations of pressed powder targets composed by both anatase and rutile phase TiO 2 . The experiments were performed in a controlled reactive atmosphere consisting of oxygen or mixtures of oxygen and nitrogen gases. The obtained thin film crystal structure was investigated by X-ray diffraction, while their chemical composition as well as chemical bonding states between the elements were studied by X-ray photoelectron spectroscopy. An interrelation was found between nitrogen concentration, crystalline structure, bonding states between the elements, and the formation of titanium oxinitride compounds. Moreover, as a result of the nitrogen incorporation in the films a continuous red-shift of the optical absorption edge accompanied by absorption in the visible spectral range between 400 and 500 nm wavelength was observed.

  9. Ozone generation in a kHz-pulsed He-O2 capillary dielectric barrier discharge operated in ambient air

    Science.gov (United States)

    Sands, Brian L.; Ganguly, Biswa N.

    2013-12-01

    The generation of reactive oxygen species using nonequilibrium atmospheric pressure plasma jet devices has been a subject of recent interest due to their ability to generate localized concentrations from a compact source. To date, such studies with plasma jet devices have primarily utilized radio-frequency excitation. In this work, we characterize ozone generation in a kHz-pulsed capillary dielectric barrier discharge configuration comprised of an active discharge plasma jet operating in ambient air that is externally grounded. The plasma jet flow gas was composed of helium with an admixture of up to 5% oxygen. A unipolar voltage pulse train with a 20 ns pulse risetime was used to drive the discharge at repetition rates between 2-25 kHz. Using UVLED absorption spectroscopy centered at 255 nm near the Hartley-band absorption peak, ozone was detected over 1 cm from the capillary axis. We observed roughly linear scaling of ozone production with increasing pulse repetition rate up to a "turnover frequency," beyond which ozone production steadily dropped and discharge current and 777 nm O(5P→5S°) emission sharply increased. The turnover in ozone production occurred at higher pulse frequencies with increasing flow rate and decreasing applied voltage with a common energy density of 55 mJ/cm3 supplied to the discharge. The limiting energy density and peak ozone production both increased with increasing O2 admixture. The power dissipated in the discharge was obtained from circuit current and voltage measurements using a modified parallel plate dielectric barrier discharge circuit model and the volume-averaged ozone concentration was derived from a 2D ozone absorption measurement. From these measurements, the volume-averaged efficiency of ozone production was calculated to be 23 g/kWh at conditions for peak ozone production of 41 mg/h at 11 kV applied voltage, 3% O2, 2 l/min flow rate, and 13 kHz pulse repetition rate, with 1.79 W dissipated in the discharge.

  10. Smooth YBa2Cu3O7-x thin films prepared by pulsed laser deposition in O2/Ar atmosphere

    DEFF Research Database (Denmark)

    Kyhle, Anders; Skov, Johannes; Hjorth, Søren

    1994-01-01

    We report on pulsed laser deposition of YBa2Cu3O7-x in a diluted O2/Ar gas resulting in thin epitaxial films which are almost outgrowth-free. Films were deposited on SrTiO3 or MgO substrates around 800-degrees-C at a total chamber pressure of 1.0 mbar, varying the argon partial pressure from 0 to 0.......6 mbar. The density of boulders and outgrowths usual for laser deposited films varies strongly with Ar pressure: the outgrowth density is reduced from 1.4 x 10(7) to 4.5 x 10(5) cm-2 with increasing Ar partial pressure, maintaining a critical temperature T(c,zero) almost-equal-to 90 K and a transport...... critical current density J(c)(77 K) greater-than-or-equal-to 10(6) A/cm2 by extended oxygenation time during cool down....

  11. Time resolved emission spectroscopy investigations of pulsed laser ablated plasmas of ZrO2 and Al2O3

    International Nuclear Information System (INIS)

    Hadoko, A D; Lee, P S; Lee, P; Mohanty, S R; Rawat, R S

    2006-01-01

    With the rising trend of synthesizing ultra thin films and/or quantum-confined materials using laser ablation, optimization of deposition parameters plays an essential role in obtaining desired film characteristics. This paper presents the initial step of plasma optimization study by examining temporal distribution of the plasma formation by pulsed laser ablation of materials. The emitted spectra of ZrO 2 and Al 2 O 3 are obtained ∼3mm above the ablated target to derive the ablated plasma characteristics. The plasma temperature is estimated to be at around 2.35 eV, with electron density of 1.14 x 10 16 (cm -3 ). Emission spectra with different gate delay time (40-270 ns) are captured to study the time resolved plume characteristics. Transitory elemental species are identified

  12. Pulsed ion-beam assisted deposition of Ge nanocrystals on SiO2 for non-volatile memory device

    International Nuclear Information System (INIS)

    Stepina, N.P.; Dvurechenskii, A.V.; Armbrister, V.A.; Kirienko, V.V.; Novikov, P.L.; Kesler, V.G.; Gutakovskii, A.K.; Smagina, Z.V.; Spesivtzev, E.V.

    2008-01-01

    A floating gate memory structure, utilizing Ge nanocrystals (NCs) deposited on tunnel SiO 2 , have been fabricated using pulsed low energy ion-beam induced molecular-beam deposition (MBD) in ultra-high vacuum. The ion-beam action is shown to stimulate the nucleation of Ge NCs when being applied after thin Ge layer deposition. Growth conditions for independent change of NCs size and array density were established allowing to optimize the structure parameters required for memory device. Activation energy E = 0.25 eV was determined from the temperature dependence of NCs array density. Monte Carlo simulation has shown that the process, determining NCs array density, is the surface diffusion. Embedding of the crystalline Ge dots into silicon oxide was carried out by selective oxidation of Si(100)/SiO 2 /Ge(NCs)/poly-Si structure. MOS-capacitor obtained after oxidation showed a hysteresis in its C-V curves attributed to charge retention in the Ge dots

  13. Descent with Modification: Thermal Reactions of Subsurface H2O2 of Relevance to Icy Satellites and Other Small Bodies

    Science.gov (United States)

    Hudson, Reggie L.; Loefler, Mark J.

    2012-01-01

    Laboratory experiments have demonstrated that magnetospheric radiation in the Jovian system drives reaction chemistry in ices at temperatures relevant to Europa and other icy satellites. Similarly, cosmic radiation (mainly protons) acting on cometary and interstellar ices can promote extensive chemical change. Among the products that have been identified in irradiated H20-ice is hydrogen peroxide (H202), which has been observed on Europa and is suspected on other worlds. Although the infrared spectra and radiation chemistry of H2O2-containing ices are well documented, the thermally-induced solid-phase chemistry of H2O2 is largely unknown. Therefore, in this presentation we report new laboratory results on reactions at 50 - 130 K in ices containing H2O2 and other molecules, both in the presence and absence of H2O. As an example of our results, we find that warming H2O + H2O2 + SO2 ices promotes SO2 oxidation to SO4(2-). We suspect that such redox chemistry may explain some of the observations related to the presence and distribution of H2O2 across Europa's surface as well as the lack of H2O2 on Ganymede and Callisto. If other molecules prove to be just as reactive with frozen H2O2 then it may explain why H2O2 has been absent from surfaces of many of the small icy bodies that are known to be exposed to ionizing radiation. Our results also have implications for the survival of H2O2 as it descends towards a subsurface ocean on Europa.

  14. Thermal Reactions of H2O2 on Icy Satellites and Small Bodies: Descent with Modification?

    Science.gov (United States)

    Hudson, Reggie L.; Loeffler, Mark J.

    2012-01-01

    Magnetospheric radiation drives surface and near-surface chemistry on Europa, but below a few meters Europa's chemistry is hidden from direct observation . As an example, surface radiation chemistry converts H2O and SO2 into H2O2 and (SO4)(sup 2-), respectively, and these species will be transported downward for possible thermally-driven reactions. However, while the infrared spectra and radiation chemistry of H2O2-containing ices are well documented, this molecule's thermally-induced solid-phase chemistry has seldom been studied. Here we report new results on thermal reactions in H2O + H2O2 + SO2 ices at 50 - 130 K. As an example of our results, we find that warming H2O + H2O2 + SO2 ices promotes SO2 oxidation to (SO4)(sup 2-). These results have implications for the survival of H2O2 as it descends, with modification, towards a subsurface ocean on Europa. We suspect that such redox chemistry may explain some of the observations related to the presence and distribution of H2O2 across Europa's surface as well as the lack of H2O2 on Ganymede and Callisto.

  15. Production of simplex RNS and ROS by nanosecond pulse N2/O2 plasma jets with homogeneous shielding gas for inducing myeloma cell apoptosis

    Science.gov (United States)

    Liu, Zhijie; Xu, Dehui; Liu, Dingxin; Cui, Qingjie; Cai, Haifeng; Li, Qiaosong; Chen, Hailan; Kong, Michael G.

    2017-05-01

    In this paper, atmospheric pressure N2/O2 plasma jets with homogeneous shielding gas excited by nanosecond pulse are obtained to generate simplex reactive nitrogen species (RNS) and reactive oxygen species (ROS), respectively, for the purpose of studying the simplex RNS and ROS to induce the myeloma cell apoptosis with the same discharge power. The results reveal that the cell death rate by the N2 plasma jet with N2 shielding gas is about two times that of the O2 plasma jet with O2 shielding gas for the equivalent treatment time. By diagnosing the reactive species of ONOO-, H2O2, OH and \\text{O}2- in medium, our findings suggest the cell death rate after plasma jets treatment has a positive correlation with the concentration of ONOO-. Therefore, the ONOO- in medium is thought to play an important role in the process of inducing myeloma cell apoptosis.

  16. Band alignment studies of Al2O3/CuGaO2 and ZnO/CuGaO2 hetero-structures grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Ajimsha, R.S.; Das, Amit K.; Joshi, M.P.; Kukreja, L.M.

    2014-01-01

    Highlights: • Band offset studies at the interface of Al 2 O 3 /CuGaO 2 and ZnO/CuGaO 2 hetero-structures were performed using X-ray photoelectron spectroscopy. • Valance band offsets (VBO) of these hetero-structures were obtained from respective XPS peak positions and VB spectra using Kraut's equation. • Al 2 O 3 /CuGaO 2 interface exhibited a type I band alignment with valance band offset (VBO) of 4.05 eV whereas type II band alignment was observed in ZnO/CuGaO 2 hetero-structure with a VBO of 2.32 eV. • Schematic band alignment diagram for the interface of these hetero-structures has been constructed. • Band offset and alignment studies of these heterojunctions are important for gaining insight to the design of various optoelectronic devices based on such hetero-structures. - Abstract: We have studied the band offset and alignment of pulsed laser deposited Al 2 O 3 /CuGaO 2 and ZnO/CuGaO 2 hetero-structures using photoelectron spectroscopy. Al 2 O 3 /CuGaO 2 interface exhibited a type I band alignment with valance band offset (VBO) of 4.05 eV whereas type II band alignment was observed in ZnO/CuGaO 2 hetero-structure with a VBO of 2.32 eV. Schematic band alignment diagram for the interface of these hetero-structures has been constructed. Band offset and alignment studies of these heterojunctions are important for gaining insight to the design of various optoelectronic devices based on such hetero-structures

  17. Photoluminescence properties of powder and pulsed laser-deposited PbS nanoparticles in SiO2

    International Nuclear Information System (INIS)

    Dhlamini, M.S.; Terblans, J.J.; Ntwaeaborwa, O.M.; Ngaruiya, J.M.; Hillie, K.T.; Botha, J.R.; Swart, H.C.

    2008-01-01

    Thin films of lead sulfide (PbS) nanoparticles embedded in an amorphous silica (SiO 2 ) host were grown on Si(1 0 0) substrates at different temperatures by the pulsed laser deposition (PLD) technique. Surface morphology and photoluminescence (PL) properties of samples were analyzed with scanning electron microscopy (SEM) and a 458 nm Ar + laser, respectively. The PL data show a blue-shift from the normal emission at ∼3200 nm in PbS bulk to ∼560-700 nm in nanoparticulate PbS powders and thin films. Furthermore, the PL emission of the films was red-shifted from that of the powders at ∼560 to ∼660 nm. The blue-shifting of the emission wavelengths from 3200 to ∼560-700 nm is attributed to quantum confinement of charge carriers in the restricted volume of nanoparticles, while the red-shift between powders and thin-film PbS nanoparticles is speculated to be due to an increase in the defect concentration. The red-shift increased slightly with an increase in deposition temperature, which suggests that there has been a relative growth in particle sizes during the PLD of the films at higher temperatures. Generally, the PL emission of the powders was more intense than that of the films, although the intensity of some of the films was improved marginally by post-deposition annealing at 400 deg. C. This paper compares the PL properties of powder and pulsed laser-deposited thin films of PbS nanoparticles and the effects of deposition temperatures

  18. Tuning the Phase and Microstructural Properties of TiO2 Films Through Pulsed Laser Deposition and Exploring Their Role as Buffer Layers for Conductive Films

    Science.gov (United States)

    Agarwal, S.; Haseman, M. S.; Leedy, K. D.; Winarski, D. J.; Saadatkia, P.; Doyle, E.; Zhang, L.; Dang, T.; Vasilyev, V. S.; Selim, F. A.

    2018-04-01

    Titanium oxide (TiO2) is a semiconducting oxide of increasing interest due to its chemical and thermal stability and broad applicability. In this study, thin films of TiO2 were deposited by pulsed laser deposition on sapphire and silicon substrates under various growth conditions, and characterized by x-ray diffraction (XRD), atomic force microscopy (AFM), optical absorption spectroscopy and Hall-effect measurements. XRD patterns revealed that a sapphire substrate is more suitable for the formation of the rutile phase in TiO2, while a silicon substrate yields a pure anatase phase, even at high-temperature growth. AFM images showed that the rutile TiO2 films grown at 805°C on a sapphire substrate have a smoother surface than anatase films grown at 620°C. Optical absorption spectra confirmed the band gap energy of 3.08 eV for the rutile phase and 3.29 eV for the anatase phase. All the deposited films exhibited the usual high resistivity of TiO2; however, when employed as a buffer layer, anatase TiO2 deposited on sapphire significantly improves the conductivity of indium gallium zinc oxide thin films. The study illustrates how to control the formation of TiO2 phases and reveals another interesting application for TiO2 as a buffer layer for transparent conducting oxides.

  19. Factors controlling the microstructure of Ce0.9Gd0.1O2-δ films in pulsed laser deposition process

    DEFF Research Database (Denmark)

    Rodrigo, Katarzyna Agnieszka; Heiroth, S.; Döbeli, M.

    2010-01-01

    Films of Ce0.9Gd0.1O2-delta (CGO10) are prepared at a range of conditions by pulsed laser deposition (PLD) on a single crystal Si (100) and MgO (100), and on a polycrystalline Pt/MgO (100) substrate. The relationship between the film microstructure, crystallography, chemical composition and PLD p...

  20. Two mechanisms of crater formation in ultraviolet-pulsed-laser irradiated SiO2 thin films with artificial defects

    International Nuclear Information System (INIS)

    Papernov, S.; Schmid, A.W.

    2005-01-01

    Atomic force microscopy was employed to investigate the morphology of ultraviolet nanosecond-pulsed-laser damage in SiO 2 thin films. Gold nanoparticles, 18.5-nm diameter, embedded in the film were used as calibrated absorbing defects. Damage-crater diameter, depth, and cross-sectional profiles were measured as a function of laser fluence and the lodging depth of gold nanoparticles. The results indicate that, at laser fluences close to the crater-formation threshold and for lodging depths of a few particle diameters, the dominating regime of the material removal is melting and evaporation. The morphology of craters initiated by deep absorbing defects, with a lodging depth larger than ∼10 particle diameters, clearly points to a two-stage material-removal mechanism. The process starts with the material melting within the narrow channel volume and, upon temperature and pressure buildup, film fracture takes place. Crater-diameter variation with lodging depth and laser fluence is compared with theoretical predictions

  1. Effects of Different Surfactants on Structural, Tribological and Electrical Properties of Pulsed Electro-Codeposited Cu-ZrO2 Composite Coatings

    Science.gov (United States)

    Maharana, H. S.; Basu, A.

    2018-03-01

    Cu-ZrO2 composite coating was synthesized by pulse electrodeposition from an acidic sulfate electrolyte dispersed with nano-sized ZrO2 particles. Effects of different surfactants in different amounts on the codeposition and distribution of ZrO2 particles in the copper matrix, surface-mechanical (hardness and wear) and electrical (conductivity) properties of developed composite coatings have been thoroughly investigated. Sodium dodecyl sulfate (SDS), poly acrylic acid (PAA) and glucose have been added in the electrolyte in different concentrations as anionic, polymeric and nonionic surfactants. Obtained experimental results confirmed that addition of SDS up to 1 g/L improves the amount of codeposited ZrO2 particles in the copper matrix and surface-mechanical properties of the nanocomposite coatings. But, in case of PAA- and glucose-assisted coatings, highest amount of ZrO2 codeposition was observed in 0.5 g/L PAA and 20 g/L glucose-assisted coatings, which in turn affected the mechanical properties. Surface-mechanical properties were found to be affected by coating matrix morphology and crystallographic orientation along with embedded ZrO2 particle content. Electrical conductivity of all the deposits not only depends upon the codeposition of ZrO2 particles in the matrix but also on the microstructure and crystallographic orientation.

  2. Enhanced ozone production in a pulsed dielectric barrier discharge plasma jet with addition of argon to a He-O2 flow gas

    Science.gov (United States)

    Sands, Brian; Ganguly, Biswa; Scofield, James

    2013-09-01

    Ozone production in a plasma jet DBD driven with a 20-ns risetime unipolar pulsed voltage can be significantly enhanced using helium as the primary flow gas with an O2 coflow. The overvolted discharge can be sustained with up to a 5% O2 coflow at pulse repetition frequency at 13 kV applied voltage. Ozone production scales with the pulse repetition frequency up to a ``turnover frequency'' that depends on the O2 concentration, total gas flow rate, and applied voltage. For example, peak ozone densities >1016 cm-3 were measured with 3% O2 admixture and discharge current and 777 nm O(5 P) emission, but decreased ozone production and is followed by a transition to a filamentary discharge mode. The addition of argon at concentrations >=5% reduces the channel conductivity and shifts the turnover frequency to higher frequencies. This results in increased ozone production for a given applied voltage and gas flow rate. Time-resolved Ar(1s5) and He(23S1) metastable densities were acquired along with discharge current and ozone density measurements to gain insight into the mechanisms of optimum ozone production.

  3. Oxidation of S(IV) in Seawater by Pulsed High Voltage Discharge Plasma with TiO2/Ti Electrode as Catalyst

    Science.gov (United States)

    Gong, Jianying; Zhang, Xingwang; Wang, Xiaoping; Lei, Lecheng

    2013-12-01

    Oxidation of S(IV) to S(VI) in the effluent of a flue gas desulfurization(FGD) system is very critical for industrial applications of seawater FGD. This paper reports a pulsed corona discharge oxidation process combined with a TiO2 photocatalyst to convert S(IV) to S(VI) in artificial seawater. Experimental results show that the oxidation of S(IV) in artificial seawater is enhanced in the pulsed discharge plasma process through the application of TiO2 coating electrodes. The oxidation rate of S(IV) using Ti metal as a ground electrode is about 2.0×10-4 mol · L-1 · min-1, the oxidation rate using TiO2/Ti electrode prepared by annealing at 500°C in air is 4.5×10-4 mol · L-1 · min-1, an increase with a factor 2.25. The annealing temperature for preparing TiO2/Ti electrode has a strong effect on the oxidation of S(IV) in artificial seawater. The results of in-situ emission spectroscopic analysis show that chemically active species (i.e. hydroxyl radicals and oxygen radicals) are produced in the pulsed discharge plasma process. Compared with the traditional air oxidation process and the sole plasma-induced oxidation process, the combined application of TiO2 photocatalysts and a pulsed high-voltage electrical discharge process is useful in enhancing the energy and conversion efficiency of S(IV) for the seawater FGD system.

  4. Evolution of local structure in Ag2O-TeO2 glasses with addition of Ag2O analyzed by pulsed neutron diffraction and Raman spectroscopy

    International Nuclear Information System (INIS)

    Iwadate, Yasuhiko; Suzuki, Mineta; Hattori, Takeo; Fukushima, Kazuko; Nishiyama, Shin; Misawa, Masakatsu; Fukunaga, Toshiharu; Itoh, Keiji

    2005-01-01

    The local structure of Ag 2 O-TeO 2 glasses was studied by time-of-flight pulsed neutron diffraction (TOF-PND) and Raman spectroscopy. The results of Raman spectroscopy indicated that TeO 4 trigonal bipyramidal units (tbp) were converted to TeO 3 trigonal pyramidal units (tp) by addition of Ag 2 O to TeO 2 . Furthermore in PND, the structural parameters for each atomic pair were optimized in the Q-space, and the distances of the near neighbor Te-O correlations forming tbp units and tp units in the network were estimated with some accuracy

  5. Independent component analysis applied to pulse oximetry in the estimation of the arterial oxygen saturation (SpO2) - a comparative study

    DEFF Research Database (Denmark)

    Jensen, Thomas; Duun, Sune Bro; Larsen, Jan

    2009-01-01

    We examine various independent component analysis (ICA) digital signal processing algorithms for estimating the arterial oxygen saturation (SpO2) as measured by a reflective pulse oximeter. The ICA algorithms examined are FastICA, Maximum Likelihood ICA (ICAML), Molgedey and Schuster ICA (ICAMS......), and Mean Field ICA (ICAMF). The signal processing includes pre-processing bandpass filtering to eliminate noise, and post-processing by calculating the SpO2. The algorithms are compared to the commercial state-of-the-art algorithm Discrete Saturation Transform (DST) by Masimo Corporation...

  6. Fabrication of highly conductive Ta-doped SnO2 polycrystalline films on glass using seed-layer technique by pulse laser deposition

    International Nuclear Information System (INIS)

    Nakao, Shoichiro; Yamada, Naoomi; Hitosugi, Taro; Hirose, Yasushi; Shimada, Toshihiro; Hasegawa, Tetsuya

    2010-01-01

    We discuss the fabrication of highly conductive Ta-doped SnO 2 (Sn 1-x Ta x O 2 ; TTO) thin films on glass by pulse laser deposition. On the basis of the comparison of X-ray diffraction patterns and resistivity (ρ) values between epitaxial films and polycrystalline films deposited on bare glass, we proposed the use of seed-layers for improving the conductivity of the TTO polycrystalline films. We investigated the use of rutile TiO 2 and NbO 2 as seed-layers; these are isostructural materials of SnO 2, which are expected to promote epitaxial-like growth of the TTO films. The films prepared on the 10-nm-thick seed-layers exhibited preferential growth of the TTO (110) plane. The TTO film with x = 0.05 on rutile TiO 2 exhibited ρ = 3.5 x 10 -4 Ω cm, which is similar to those of the epitaxial films grown on Al 2 O 3 (0001).

  7. Influence of ion bombardment on structural and electrical properties of SiO2 thin films deposited from O2/HMDSO inductively coupled plasmas under continuous wave and pulsed modes

    International Nuclear Information System (INIS)

    Bousquet, A.; Goullet, A.; Leteinturier, C.; Granier, A.; Coulon, N.

    2008-01-01

    Low pressure Plasma Enhanced Chemical Vapour Deposition is commonly used to deposit insulators on temperature sensitive substrates. In these processes, the ion bombardment experienced by films during its growth is known to have benefits but also some disadvantages on material properties. In the present paper, we investigate the influence of this bombardment on the structure and the electrical properties of SiO 2 -like film deposited from oxygen/hexa-methyl-di-siloxane radiofrequency plasma in continuous and pulsed modes. First, we studied the ion kinetics thanks to time-resolved measurements by Langmuir probe. After, we showed the ion bombardment in such plasma controls the OH bond content in deposited films. Finally, we highlight the impressive reduction of fixed charge and interface state densities in films obtained in pulsed mode due to a lower ion bombardment. (authors)

  8. Photoelectrocatalytic decomposition of ethylene using TiO2/activated carbon fiber electrode with applied pulsed direct current square-wave potential

    International Nuclear Information System (INIS)

    Ye, Sheng-ying; Zheng, Sen-hong; Song, Xian-liang; Luo, Shu-can

    2015-01-01

    Highlights: • Ethylene was decomposed by a photoelectrocatalytic (PEC) process. • A pulsed direct current square-wave (PDCSW) potential was applied to the PEC cell. • An electrode of TiO 2 or modified TiO 2 and activated carbon fiber (ACF) was used. • TiO 2 /ACF photocatalyst electrodes were modified by gamma radiolysis. • Efficiencies of the PEC process were higher than those of the process using DC. - Abstract: Removing ethylene (C 2 H 4 ) from the atmosphere of storage facilities for fruits and vegetable is one of the main challenges in their postharvest handling for maximizing their freshness, quality, and shelf life. In this study, we investigated the photoelectrocatalytic (PEC) degradation of ethylene gas by applying a pulsed direct current DC square-wave (PDCSW) potential and by using a Nafion-based PEC cell. The cell utilized a titanium dioxide (TiO 2 ) photocatalyst or γ-irradiated TiO 2 (TiO 2 * ) loaded on activated carbon fiber (ACF) as a photoelectrode. The apparent rate constant of a pseudo-first-order reaction (K) was used to describe the PEC degradation of ethylene. Parameters of the potential applied to the PEC cell in a reactor that affect the degradation efficiency in terms of the K value were studied. These parameters were frequency, duty cycle, and voltage. Ethylene degradation by application of a constant PDCSW potential to the PEC electrode of either TiO 2 /ACF cell or TiO 2 * /ACF cell enhanced the efficiency of photocatalytic degradation and PEC degradation. Gamma irradiation of TiO 2 in the electrode and the applied PDCSW potential synergistically increased the K value. Independent variables (frequency, duty cycle, and voltage) of the PEC cell fabricated from TiO 2 subjected 20 kGy γ radiation were optimized to maximize the K value by using response surface methodology with quadratic rotation–orthogonal composite experimental design. Optimized conditions were as follows: 358.36 Hz frequency, 55.79% duty cycle, and 64.65 V

  9. Exercise Improves V˙O2max and Body Composition in Androgen Deprivation Therapy-treated Prostate Cancer Patients.

    Science.gov (United States)

    Wall, Bradley A; GALVãO, Daniel A; Fatehee, Naeem; Taaffe, Dennis R; Spry, Nigel; Joseph, David; Hebert, Jeffrey J; Newton, Robert U

    2017-08-01

    Prostate cancer is the most common cancer in men, and patients treated with androgen deprivation therapy (ADT) experience unfavorable changes in body composition and associated metabolic complications, which can increase the risk of cardiovascular disease. We examined the effect of a 6-month program of aerobic and resistance exercise aimed at improving body composition and cardiorespiratory health in this population. Ninety-seven men (43-90 yr) with localized prostate cancer receiving ADT were randomized to either exercise (EX, n = 50) or usual care (CON, n = 47). Supervised exercise was undertaken twice weekly at moderate to high intensity. Measures of cardiorespiratory capacity (V˙O2max), resting metabolic rate, central blood pressure, hemodynamic variables, blood markers, and body composition were assessed. There was a significant group-time interaction present for V˙O2max (P = 0.033) with a treatment effect for EX of 0.11 L·min (95% confidence interval [CI] = 0.04-0.19) (relative to body mass = 1.3 mL·kg·min, 95% CI = 0.3-2.3) and fat oxidation (P = 0.037) of 12.0 mg·min (95% CI = 2.3-21.7). Similarly, there was a significant improvement in glucose (P Body composition was enhanced for EX with adjusted mean differences in lean mass (P = 0.015) of 0.8 kg (95% CI = 0.3-1.3), total fat mass (P = 0.020) of -1.1 kg (95% CI = -1.8 to -0.5), and trunk fat mass (P body composition despite the adverse effects of hormone suppression. Combined aerobic and resistance training should be considered a key adjuvant component in men undergoing ADT for the treatment of prostate cancer.

  10. Optical and electrical properties of SnO2 thin films after ultra-short pulsed laser annealing

    NARCIS (Netherlands)

    Scorticati, D.; Illiberi, A.; Römer, G.R.B.E.; Bor, T.; Ogieglo, W.; Klein Gunnewiek, M.; Lenferink, A.; Otto, C.; Skolski, J.Z.P.; Grob, F.; Lange, D.F. de; Huis in 't Veld, A.J.

    2013-01-01

    Ultra-short pulsed laser sources, with pulse durations in the ps and fs regime, are commonly exploited for cold ablation. However, operating ultra-short pulsed laser sources at fluence levels well below the ablation threshold allows for fast and selective thermal processing. The latter is especially

  11. A charge-optimized many-body potential for the U-UO2-O2 system

    Science.gov (United States)

    Li, Yangzhong; Liang, Tao; Sinnott, Susan B.; Phillpot, Simon R.

    2013-12-01

    Building on previous charge-optimized many-body (COMB) potentials for metallic α-U and gaseous O2, we have developed a new potential for UO2, which also allows the simulation of U-UO2-O2 systems. The UO2 lattice parameter, elastic constants and formation energies of stoichiometric and non-stoichiometric intrinsic defects are well reproduced. Moreover, this is the first rigid-ion potential that produces the correct deviation of the Cauchy relation, as well as the first classical interatomic potential that is able to determine the defect energies of non-stoichiometric intrinsic point defects in UO2 with an appropriate reference state. The oxygen molecule interstitial in the α-U structure is shown to decompose, with some U-O bonds approaching the natural bond length of perfect UO2. Finally, we demonstrate the capability of this COMB potential to simulate a complex system by performing a simulation of the α-U + O2 → UO2 phase transformation. We also identify a possible mechanism for uranium oxidation and the orientation of the resulting fluorite UO2 structure relative to the coordinate system of orthorhombic α-U.

  12. Epitaxial single-crystal thin films of MnxTi1-xO2-δ grown on (rutile)TiO2 substrates with pulsed laser deposition: Experiment and theory

    Energy Technology Data Exchange (ETDEWEB)

    Ilton, Eugene S.; Droubay, Timothy C.; Chaka, Anne M.; Kovarik, Libor; Varga, Tamas; Arey, Bruce W.; Kerisit, Sebastien N.

    2015-02-01

    Epitaxial rutile-structured single-crystal MnxTi1-xO2-δ films were synthesized on rutile- (110) and -(001) substrates using pulsed laser deposition. The films were characterized by reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and aberration-corrected transmission electron microscopy (ACTEM). Under the present conditions, 400oC and PO2 = 20 mTorr, single crystal epitaxial thin films were grown for x = 0.13, where x is the nominal average mole fraction of Mn. In fact, arbitrarily thick films could be grown with near invariant Mn/Ti concentration profiles from the substrate/film interface to the film surface. In contrast, at x = 0.25, Mn became enriched towards the surface and a secondary nano-scale phase formed which appeared to maintain the basic rutile structure but with enhanced z-contrast in the tunnels, or tetrahedral interstitial sites. Ab initio thermodynamic calculations provided quantitative estimates for the destabilizing effect of expanding the β-MnO2 lattice parameters to those of TiO2-rutile, the stabilizing effect of diluting Mn with increasing Ti concentration, and competing reaction pathways.

  13. Zr O2-Y2 O3 ceramic bodies forming by slip casting

    International Nuclear Information System (INIS)

    Menezes, Cristiane A.B. de; Menezes, Fernanda; Ussui, Valter; Lazar, Dolores R.R.; Paschoal, Jose Otavio A.

    1996-01-01

    Slip casting technique of 3 mol% yttria stabilized zirconia powders suspensions has been used for ceramic bodies forming. The powders were produced by coprecipitation process with ammonium hydroxide in the Zirconium Pilot Plant of IPEN (Institute for Energy and Nuclear Researches, Sao Paulo, SP, (Brazil). Experiments were performed by preparing suspensions of powders with dispersing agents. These suspensions were submitted to milling and casting in plaster molds. After drying and heating at 700 deg C, the obtained specimens were sintered at 1500 deg C for 3 hours. The ceramic bodies were investigated by scanning electron microscopy and X-ray diffraction, and tested in high temperature conditions. (author)

  14. Influence of O2 Flux on Compositions and Properties of ITO Films Deposited at Room Temperature by Direct-Current Pulse Magnetron Sputtering

    International Nuclear Information System (INIS)

    Wang Hua-Lin; Ding Wan-Yu; Liu Chao-Qian; Chai Wei-Ping

    2010-01-01

    Indium tin oxide (ITO) films were deposited on glass substrates at room temperature by dc pulse magnetron sputtering. Varying O 2 flux, ITO films with different properties are obtained. Both x-ray diffractometer and x-ray photoelectron spectrometer are used to study the change of crystalline structures and bonding structures of ITO films, respectively. Electrical properties are measured by four-point probe measurements. The results indicate that the chemical structures and compositions of ITO films strongly depend on the O 2 flux. With increasing O 2 flux, ITO films display better crystallization, which could decrease the resistivity of films. On the contrary, ITO films contain less O vacancies with increasing O 2 flux, which could worsen the conductive properties of films. Without any heat treatment onto the samples, the resistivity of the ITO film could reach 6.0 × 10 −4 Ω ·cm, with the optimal deposition parameter of 0.2 sccm O 2 flux. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  15. Effect of whole body irradiation on O2- production in polymorphonuclear leukocyte of guinea pig

    International Nuclear Information System (INIS)

    Niiya, Harutaka

    1987-01-01

    The capacity of superoxide anion production of polymorphonuclear leukocytes (PMNL) has been determined after whole body irradiation. A diminished capacity of superoxide anion production in the presence of opsonized zymosan was found in PMNL taken from guinea pigs irradiated in vivo with 5, 10, and 20 Gy. However, no such diminution was found after a dose of 2 Gy. On the other hand, levels of superoxide anion production stimulated by myristate, N-Formyl-Methionyl-Leucyl-Phenylalanine (FMLP), and Concanavalin A remained unchanged compared to the control. PMNL irradiated in vitro with 20 Gy had a capacity of superoxide anion production similar to that of the control samples in the presence of either opsonized zymosan or FMLP and myristate. These results suggest that the capacity of superoxide anion production stimulated by zymosan is damaged by whole body irradiation. (author)

  16. Biocompatibility assessment of graphene oxide-hydroxyapatite coating applied on TiO2 nanotubes by ultrasound-assisted pulse electrodeposition.

    Science.gov (United States)

    Fathyunes, Leila; Khalil-Allafi, Jafar; Sheykholeslami, Seyed Omid Reza; Moosavifar, Maryam

    2018-06-01

    In this study, the ultrasound-assisted pulse electrodeposition was introduced to fabricate the graphene oxide (GO)-hydroxyapatite (HA) coating on TiO 2 nanotubes. The results of the X-ray diffraction (XRD), Fourier Transform Infrared spectroscope (FTIR), Transmission Electron Microscope (TEM) and micro-Raman spectroscopy showed the successful synthesis of GO. The Scanning Electron Microscope (SEM) images revealed that in the presence of ultrasonic waves and GO sheets a more compact HA-based coating with refined microstructure could be formed on the pretreated titanium. The results of micro-Raman analysis confirmed the successful incorporation of the reinforcement filler of GO into the coating electrodeposited by the ultrasound-assisted method. The FTIR analysis showed that the GO-HA coating was consisted predominantly of the B-type carbonated HA (CHA) phase. The pretreatment of the substrate and incorporation of the GO sheets into the HA coating had a significant effect on improving the bonding strength at the coating-substrate interface. Moreover, the results of the fibroblast cell culture and 3‑(4,5‑dimethylthiazolyl‑2)‑2, 5‑diphenyltetrazolium bromide (MTT) assay after 2 days demonstrated a higher percentage of cell activity for the GO-HA coated sample. Finally, the 7-day exposure to simulated body fluid (SBF) showed a faster rate of apatite precipitation on the GO-HA coating, as compared to the HA coating and pretreated titanium. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Optical and electrical properties of SnO2 thin films after ultra-short pulsed laser annealing

    OpenAIRE

    Scorticati, D.; Illiberi, A.; Römer, G.R.B.E.; Bor, T.; Ogieglo, W.; Klein Gunnewiek, M.; Lenferink, A.; Otto, C.; Skolski, J.Z.P.; Grob, F.; Lange, D.F. de; Huis in 't Veld, A.J.

    2013-01-01

    Ultra-short pulsed laser sources, with pulse durations in the ps and fs regime, are commonly exploited for cold ablation. However, operating ultra-short pulsed laser sources at fluence levels well below the ablation threshold allows for fast and selective thermal processing. The latter is especially advantageous for the processing of thin films. A precise control of the heat affected zone, as small as tens of nanometers, depending on the material and laser conditions, can be achieved. It enab...

  18. Body acceleration distribution and O2 uptake in humans during running and jumping

    Science.gov (United States)

    Bhattacharya, A.; Mccutcheon, E. P.; Shvartz, E.; Greenleaf, J. E.

    1980-01-01

    The distribution of body acceleration and associated oxygen uptake and heart rate responses are investigated in treadmill running and trampoline jumping. Accelerations in the +Gz direction were measured at the lateral ankle, lumbosacral region and forehead of eight young men during level treadmill walking and running at four speeds and trampoline jumping at four heights, together with corresponding oxygen uptake and heart rate. With increasing treadmill speed, peak acceleration at the ankle is found always to exceed that at the back and forehead, and acceleration profiles with higher frequency components than those observed during jumping are observed. Acceleration levels are found to be more uniformly distributed with increasing height in jumping, although comparable oxygen uptake and heat rates are obtained. Results indicate that the magnitude of the biomechanical stimuli is greater in trampoline jumping than in running, which finding could be of use in the design of procedures to avert deconditioning in persons exposed to weightlessness.

  19. Films of brookite TiO2 nanorods/nanoparticles deposited by matrix-assisted pulsed laser evaporation as NO2 gas-sensing layers

    Science.gov (United States)

    Caricato, A. P.; Buonsanti, R.; Catalano, M.; Cesaria, M.; Cozzoli, P. D.; Luches, A.; Manera, M. G.; Martino, M.; Taurino, A.; Rella, R.

    2011-09-01

    Titanium dioxide (TiO2) nanorods in the brookite phase, with average dimensions of 3-4 nm × 20-50 nm, were synthesized by a wet-chemical aminolysis route and used as precursors for thin films that were deposited by the matrix-assisted pulsed laser evaporation (MAPLE) technique. A nanorod solution in toluene (0.016 wt% TiO2) was frozen at the liquid-nitrogen temperature and irradiated with a KrF excimer laser at a fluence of 350 mJ/cm2 and repetition rate of 10 Hz. Single-crystal Si wafers, silica slides, carbon-coated Cu grids and alumina interdigitated slabs were used as substrates to allow performing different characterizations. Films fabricated with 6000 laser pulses had an average thickness of ˜150 nm, and a complete coverage of the selected substrate as achieved. High-resolution scanning and transmission electron microscopy investigations evidenced the formation of quite rough films incorporating individually distinguishable TiO2 nanorods and crystalline spherical nanoparticles with an average diameter of ˜13 nm. Spectrophotometric analysis showed high transparency through the UV-Vis spectral range. Promising resistive sensing responses to 1 ppm of NO2 mixed in dry air were obtained.

  20. Ion beam modification of structural and optical properties of GeO2 thin films deposited at various substrate temperatures using pulsed laser deposition

    Science.gov (United States)

    Rathore, Mahendra Singh; Vinod, Arun; Angalakurthi, Rambabu; Pathak, A. P.; Singh, Fouran; Thatikonda, Santhosh Kumar; Nelamarri, Srinivasa Rao

    2017-11-01

    High energy heavy ion irradiation-induced modification of high quality crystalline GeO2 thin films grown at different substrate temperatures ranging from 100 to 500 °C using pulsed laser deposition has been investigated. The pristine films were irradiated with 100 MeV Ag7+ ions at fixed fluence of 1 × 1013 ions/cm2. These pristine and irradiated films have been characterized using X-ray diffraction, atomic force microscopy, Raman spectroscopy, Fourier transform infrared and photoluminescence spectroscopy. The XRD and Raman results of pristine films confirm the formation of hexagonal structure of GeO2 films, whereas the irradiation eliminates all the peaks except major GeO2 peak of (101) plane. It is evident from the XRD results that crystallite size changes with substrate temperature and SHI irradiation. The surface morphology of films was studied by AFM. The functional group of pristine and irradiated films was investigated by IR transmission spectra. Pristine films exhibited strong photoluminescence around 342 and 470 nm due to oxygen defects and a red shift in the PL bands is observed after irradiation. Possible mechanism of tuning structural and optical properties of pristine as well as irradiated GeO2 films with substrate temperature and ion beam irradiation has been reported in detail.

  1. Influence of annealing temperature on structural and magnetic properties of pulsed laser-deposited YIG films on SiO2 substrate

    Science.gov (United States)

    Nag, Jadupati; Ray, Nirat

    2018-05-01

    Yttrium Iron Garnet (Y3Fe5O12) was synthesized by solid state/ceramic process. Thin films of YIG were deposited on SiO2 substrate at room temperature(RT) and at substrate temperature (Ts) 700 °C using pulsed laser deposition (PLD) technique. RT deposited thin films are amorphous in nature and non-magnetic. After annealing at temperature 800 ° RT deposited thin films showed X-ray peaks as well as the magnetic order. Magnetic ordering is enhanced by annealing temperature(Ta ≥ 750 °C) and resulted good quality of films with high magnetization value.

  2. Interfacial electron-transfer equilibria and flat-band potentials of α-Fe2O3 and TiO2 colloids studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Dimitrijevic, N.M.; Savic, D.; Micic, O.I.; Nozik, A.J.

    1984-01-01

    The kinetics and equilibria of electron transfer between methylviologen cation radicals and α-Fe 2 O 3 or TiO 2 colloidal particles were studied with the pulse-radiolysis technique. The rates of electron transfer to both colloids are lower than those predicted for a diffusion-controlled reaction. For higher pHs (TiO 2 , pH > 2; α-Fe 2 O 3 , pH > 9) the established equilibrium MV + in equilibrium MV 2+ + (e - )/sub coll/ is strongly influenced by the MV 2+ concentration and pH. The MV + equilibrium concentration can be exploited to derive the flat-band potential of the semiconductor colloids. The method for determining the flat-band potential of the particles is independent of whether the injected electrons are free or trapped, and whether the electrons raise the bulk Fermi level toward the conduction band or just produce a space charge. The flat-band potentials for both colloids appear to be somewhat more negative (-0.1 to -0.2 V) than the corresponding single-crystal electrodes. Also, the flat-band potentials become slightly more negative with increasing radiation dose (initial MV + concentration). The effect of absorbed radiation dose is explained by the corresponding changes in the ratio of oxidized to reduced forms of the redox couple, which in turn changes the adsorbed ionic charge on the semiconductor surface. For colloidal particles of TiO 2 stabilized by poly(vinyl alcohol) (PVA), the flat-band potentials were almost the same as those for PVA-free TiO 2 sols. The decrease of particle diameter from 800 to 70 A does not affect the value of the flat-band potentials for TiO 2 and α-Fe 2 O 3 colloids. 28 references, 9 figures

  3. The effect of O2 partial pressure on the photoluminescence of ZnO thin films grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Lu, Y.M.; Li, X.P.; Su, S.C.; Cao, P.J.; Jia, F.; Han, S.; Zeng, Y.X.; Liu, W.J.; Zhu, D.L.

    2014-01-01

    In this paper, photoluminescence (PL) of ZnO thin films prepared on c-Al 2 O 3 substrates by the pulsed laser deposition (PLD) method at different O 2 partial pressures is investigated. For all samples, a narrow ultraviolet (UV) emission and a broad visible emission can be observed at room-temperature (RT). With increasing O 2 partial pressures from 0.2 to 5 Pa, the intensity ratio of the UV to visible emissions increases, and the energy positions of the UV emission band shift to the high energy side. It is noted that the visible part includes two emission bands of green luminescence (GL) and yellow luminescence (YL), in which the GL emission is strong at low oxygen pressure and the YL emission becomes dominant at high O 2 partial pressures. The temperature-dependent PL spectra show that the UV emission is composed of two bands labeled FX and FA. The dependences and possible assignments of these PL bands are briefly discussed. - Highlights: • We confirmed that the RT UV emission band is due to two transitions of the FX and FA. • The intensity of the FX and FA emission bands strongly depends on oxygen partial pressures. • We deduced that the acceptor-like defects located in the grain boundaries are responsible for the FA emission. • The visible emission includes the GL related to V O and the YL related to V Zn or O i . • The GL emission strongly affects the UV emission

  4. Following dynamic nuclear wave packets in N2,O2, and CO with few-cycle infrared pulses

    International Nuclear Information System (INIS)

    De, S.; Magrakvelidze, M.; Bocharova, I. A.; Ray, D.; Cao, W.; Li, H.; Wang, Z.; Laurent, G.; Thumm, U.; Ben-Itzhak, I.; Cocke, C. L.; Znakovskaya, I.; Kling, M. F.; Litvinyuk, I. V.

    2011-01-01

    We study the evolution of nuclear wave packets launched in molecular nitrogen, oxygen, and carbon monoxide by intense 8-fs infrared pulses. We use velocity map imaging to measure the momentum of the ion fragments when these wave packets are interrogated by a second such pulse after a variable time delay. Both quasibound and dissociative wave packets are observed. For the former, measurements of bound-state oscillations are used to identify the participating states and, in some cases, extract properties of the relevant potential-energy surfaces. Vibrational structure is resolved in both energy and oscillation frequencies for the cations of oxygen and carbon monoxide, displaying the same quantum wave-packet motion in both energy and time domains. In addition, vibrational structure is seen in the dication of carbon monoxide in a situation where the energy resolution by itself is inadequate to resolve the structure.

  5. Following dynamic nuclear wave packets in N2,O2, and CO with few-cycle infrared pulses

    Science.gov (United States)

    de, S.; Magrakvelidze, M.; Bocharova, I. A.; Ray, D.; Cao, W.; Znakovskaya, I.; Li, H.; Wang, Z.; Laurent, G.; Thumm, U.; Kling, M. F.; Litvinyuk, I. V.; Ben-Itzhak, I.; Cocke, C. L.

    2011-10-01

    We study the evolution of nuclear wave packets launched in molecular nitrogen, oxygen, and carbon monoxide by intense 8-fs infrared pulses. We use velocity map imaging to measure the momentum of the ion fragments when these wave packets are interrogated by a second such pulse after a variable time delay. Both quasibound and dissociative wave packets are observed. For the former, measurements of bound-state oscillations are used to identify the participating states and, in some cases, extract properties of the relevant potential-energy surfaces. Vibrational structure is resolved in both energy and oscillation frequencies for the cations of oxygen and carbon monoxide, displaying the same quantum wave-packet motion in both energy and time domains. In addition, vibrational structure is seen in the dication of carbon monoxide in a situation where the energy resolution by itself is inadequate to resolve the structure.

  6. Repeatability of Pulse Diagnosis and Body Constitution Diagnosis in Traditional Indian Ayurveda Medicine

    Science.gov (United States)

    Waagepetersen, Rasmus; Toft, Egon; Prasad, Ramjee; Raturi, Lokesh

    2012-01-01

    In Ayurveda, pulse diagnosis and body constitution diagnosis have a long historical use; still, there is lack of quantitative measure of the reliability of these diagnostic methods. Reliability means consistency of information. Consistent diagnosis leads to consistent treatment and is important for clinical practice, education, and research. The objective of this study is to study the methodology to evaluate the test-retest reliability (repeatability) of pulse diagnosis and body constitution diagnosis. A double-blinded, controlled, clinical trial was conducted in Copenhagen. The same doctor, an expert in Ayurvedic pulse diagnosis, examined the pulse and body constitution of 17 healthy participants twice, in random order without seeing them. A metric on pulse and body constitution variables was developed. Cohen's weighted kappa statistic was used as a measure of intra-rater reliability. Permutation tests were used to test the hypothesis of homogeneous diagnosis (ie, the doctor's diagnosis does not depend on the subject). The hypothesis of homogeneous classification was rejected on the 5% significance level (P values of .02 and .001, respectively, for pulse and body constitution diagnosis). According to the Landis and Koch scale, values of the weighted kappa for pulse diagnosis (P = .42) and body constitution diagnosis (P = .65) correspond to “moderate” and “substantial” agreement, respectively. There was a reasonable level of consistency between 2 pulse and body constitution diagnoses. Further studies are required to quantify inter-subject and intra-subject agreement for greater understanding of reliability of pulse and body constitution diagnosis. PMID:27257530

  7. Electrical and optical characteristics of ITO films by pulsed laser deposition using a 10 wt.% SnO2-doped In2O3 ceramic target

    International Nuclear Information System (INIS)

    Kim, Sang Hyeob; Park, Nae-Man; Kim, TaeYoub; Sung, GunYong

    2005-01-01

    We have investigated the effect of the oxygen pressure and the deposition temperature on the electrical and optical properties of the Sn-doped indium oxide (ITO) films on quartz glass substrate by pulsed laser deposition (PLD) using a 10 wt.% SnO 2 -doped In 2 O 3 target. The resistivity and the carrier concentration of the films were decreased due to the decrease of the oxygen vacancy while increasing the oxygen pressure. With increasing deposition temperature, the resistivity of the films was decreased and the carrier concentration was increased due to the grain growth and the enhancement of the Sn diffusion. We have optimized the PLD process to deposit a highly conductive and transparent ITO film, which shows the optical transmittance of 88% and the resistivity of 2.49x10 -4 Ω cm for the film thickness of 180 nm

  8. Relation between crystallinity and chemical nature of surface on wettability: A study on pulsed laser deposited TiO2 thin films

    International Nuclear Information System (INIS)

    Shirolkar, Mandar M.; Phase, Deodatta; Sathe, Vasant; Choudhary, Ram Janay; Rodriguez-Carvajal, J.; Kulkarni, Sulabha K.

    2011-01-01

    Pure titania (TiO 2 ) polycrystalline thin films in rutile, anatase and mixed phase have been grown on amorphous glass substrates by pulsed laser deposition method at various oxygen gas pressure. Wettability investigations have been carried out on these films. Consistent with our previous report [J. Phys. D: Appl. Phys. 41, 155308 (2008)] it has been observed that for nearly same surface roughness large contact angle or superhydrophobicity is present when sample has a pure single phase and lower contact angle or hydrophobicity when mixed phases were present. Structural characterizations suggest that in addition to roughness, pure phase film surface associated with hydrophobic sites and mixed phase film surface show association of both hydrophobic and hydrophilic sites, which might be inducing specific wetting character. UV treatment induces superhydrophilicity in the films. It was observed that UV irradiation causes nonequilibrium state on the TiO 2 surface, leading to changes in the electron density, which in turn produces decrement in the crystallinity and lattice expansion. Reversible changes in the wetting state on the pure phase surfaces were observed to be faster than those on the mixed phase surfaces. We tried to establish the possible relation between crystalline phases, chemical nature of surface on reversible wettability besides the main governing parameter viz. surface roughness.

  9. Comparison of precursors for pulsed metal-organic chemical vapor deposition of HfO2 high-K dielectric thin films

    International Nuclear Information System (INIS)

    Teren, Andrew R.; Thomas, Reji; He, Jiaqing; Ehrhart, Peter

    2005-01-01

    Hafnium oxide films were deposited on Si(100) substrates using pulsed metal-organic chemical vapor deposition (CVD) and evaluated for high-K dielectric applications. Three types of precursors were tested: two oxygenated ones, Hf butoxide-dmae and Hf butoxide-mmp, and an oxygen-free one, Hf diethyl-amide. Depositions were carried out in the temperature range of 350-650 deg. C, yielding different microstructures ranging from amorphous to crystalline, monoclinic, films. The films were compared on the basis of growth rate, phase development, density, interface characteristics, and electrical properties. Some specific features of the pulsed injection technique are considered. For low deposition temperatures the growth rate for the amide precursor was significantly higher than for the mixed butoxide precursors. A thickness-dependent amorphous to crystalline phase transition temperature was found for all precursors. There is an increase of the film density along with the deposition temperature from values as low as 5 g/cm 3 at 350 deg. C to values close to the bulk value of 9.7 g/cm 3 at 550 deg. C. Crystallization is observed in the same temperature range for films of typically 10-20 nm thickness. However, annealing studies show that this density increase is not simply related to the crystallization of the films. Similar electrical properties could be observed for all precursors and the dielectric constant of the films reaches values similar to the best values reported for bulk crystalline HfO 2

  10. On red-shift of UV photoluminescence with decreasing size of silicon nanoparticles embedded in SiO2 matrix grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Chaturvedi, Amita; Joshi, M.P.; Rani, Ekta; Ingale, Alka; Srivastava, A.K.; Kukreja, L.M.

    2014-01-01

    Ensembles of silicon nanoparticles (Si-nps) embedded in SiO 2 matrix were grown by alternate ablation of Si and SiO 2 targets using KrF excimer laser based pulsed laser deposition (PLD). The sizes of Si-nps (mean size ranging from 1–5 nm) were controlled by varying the ablation time of silicon target. Transmission electron microscopy (TEM) along with selected area electron diffraction (SAED) and Raman spectroscopy were used to confirm the growth of silicon nanoparticles, its size variation with growth time and the crystalline quality of the grown nanoparticles. TEM analysis showed that mean size and size distribution of Si-nps increased with increase in the ablation time of Si target. Intense peaks ∼521 cm −1 in Raman analysis showed reasonably good crystalline quality of grown Si-nps. We observed asymmetric broadening of phonon line shapes which also redshift with decreasing size of Si-nps. Photoluminescence (PL) from these samples, obtained at room temperature, was broad band and consisted of three bands in UV and visible range. The intensity of PL band in UV spectral range (peak ∼3.2 eV) was strong compared to visible range bands (peaks ∼2.95 eV and ∼2.55 eV). We observed a small red-shift (∼0.07 eV) of peak position of UV range PL with the decrease in the mean sizes of Si-nps, while there was no appreciable size dependent shift of PL peak positions for other bands in the visible range. The width of UV PL band was also found to increase with decrease of Si-nps mean sizes. Based on the above observations of size dependent redshift of UV range PL band together with the PL lifetimes and PL excitation spectroscopy, the origin of UV PL band is attributed to the direct band transition at the Γ point of Si band structure. Visible range bands were ascribed as defect related transitions. The weak intensities of PL bands ∼2.95 eV and ∼2.55 eV suggested that Si nanoparticles grown by PLD were efficiently capped or passivated by SiO 2 with low density of

  11. Pulsed electric field improves the bioprotective capacity of purées for different coloured carrot cultivars against H2O2-induced oxidative damage.

    Science.gov (United States)

    Leong, Sze Ying; Oey, Indrawati; Burritt, David John

    2016-04-01

    This research aimed to study the effect of pulsed electric field (PEF) processing on the bioprotective capacity of carrot purée for White Belgian, Yellow Solar, Nantes, Nutri Red and Purple Haze cultivars against H2O2-induced oxidative damage. The bioprotective capacity was determined using cell viability, membrane integrity and nitric oxide (NO) production in a human Caco-2 cell culture assay. Total carotenoids, total anthocyanins, total vitamin C and total phenolics were also evaluated. Compared to the untreated purée, Purple Haze and Nutri Red processed at 303 kJ/kg completely increased Caco-2 cells resistance towards oxidative damage by recovering the cell viability and inhibiting NO production. For cultivar with low carotenoid levels, i.e. Yellow Solar, the application of 0.8 kV/cm resulted in a higher total carotenoid content in the purée than its untreated counterpart, leading to an improved bioprotective effect. This study clearly shows that PEF could add value to carrots by maximising bioprotective effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Pulsed Joining Of Body-In-White Components

    Energy Technology Data Exchange (ETDEWEB)

    Bonnen, John [Ford Motor Company, Dearborn, MI (United States)

    2014-09-30

    The objective of this project was to develop cost efficient high quality pulsed welding (PW) technology for joining 6xxx Aluminum and High Strength Steel (with tensile strength above 580MPa) components enabling broad usage of hydroformed parts and leading to substantial weight reduction of cars and trucks to reduce US demand on petroleum, lower carbon emissions and energy expenditures. In general, pulsed welding is a form of impact welding where two dissimilar metal pieces are joined by accelerating one to velocities exceeding 300m/s at which point the first piece strikes the second and forms a weld. In this work, two methods were used to accelerate the flyer material: Electro-Magnetic (EM) pulse and Electro-Hydraulic (EH) pulse launching. The advantage of pulsed welding techniques is that welds can be formed between two materials that cannot otherwise be welded: high strength aluminum and high strength steel. The technical objectives of the project included: 1) developing cost affordable production feasible tooling design for PW of 6xxx aluminum to High Strength steel with strengths above 580MPa; 2) demonstrating that fabricated joints can exceed the required service load strength initially at the coupon level and then at the component level; 3) developing fundamental understanding of the mechanisms of joint formation and conditions leading to formation of high quality PW joint; and 4) creating a numerical model predicting the tooling and electric discharge parameters necessary for the joint formation and that satisfy the targeted strength parameters. The project successfully developed: 1) EM and EH pulsed welds between high strength aluminum with tensile strengths exceeding 240MPa and steels exceeding 580MPa; 2) pulsed welds of extrusions with strengths exceeding project requirements; 3) EM and EH flyer launch models and 4) weld interface formation models. However, the grant holder, Ford Motor Company, could see no path to commercialization and the work was

  13. The Cr Redox Record of fO2 Variation in Angrites. Evidence for Redox Conditions of Angrite Petrogenesis and Parent Body

    Science.gov (United States)

    Shearer, Charles K.; Bell, Aaron S.; Burger, Paul V.; Papike, James J.; Jones, John; Le, Loan

    2016-01-01

    Angrites represent some of the earliest stages of planetesimal differentiation. Not surprisingly, there is no simple petrogenetic model for their origin. Petrogenesis has been linked to both magmatic and impact processes. Studies demonstrated that melting of chondritic material (e.g. CM, CV) at redox conditions where pure iron metal is unstable (e.g., IW+1 to IW+2) produced angrite-like melts. Alternatively, angrites were produced at more reducing conditions (redox conditions during crystallization (e.g., Fe metal and a Fe-Ti oxide with potential Fe3+. There have been several estimates of fO2 for angrites. Most notably, experiments examined the variation of DEu/DGd with fO2, between plagioclase and fassaitic pyroxene in equilibrium with an angrite melt composition. They used their observations to estimate the fO2 of crystallization to be approximately IW+0.6 for angrite LEW 86010. This estimate is only a "snapshot" of fO2 conditions during co-crystallization of plagioclase and pyroxene. Preliminary XANES analyses of V redox state in pyroxenes from D'Orbigny reported changes in fO2 from IW-0.7 during early pyroxene crystallization to IW+0.5 during latter episodes of pyroxene crystallization [15]. As this was a preliminary report, it presented limited information concerning the effects of pyroxene orientation and composition on the V valence measurements, and the effect of melt composition on valence and partitioning behavior of V. A closer examination of fO2 as recorded by Cr valence state in olivine will allow us to test models for primordial melting of chondritic material to produce the angrite parent melts. Here, we report the our initial stages of examining the origin and conditions of primordial melting on the angrite parent body and test some of the above models by integrating an experimental study of Cr and V valence partitioning between olivine [OL] and an angrite melt, with micro-scale determinations of Cr and V oxidation state in OL in selected "volcanic

  14. Resistive switching effects in CeO2/La0.7(Sr0.1Ca0.9)0.3MnO3/Pt heterostructures prepared by pulse laser deposition method

    International Nuclear Information System (INIS)

    Chen, X.G.; Fu, J.B.; Li, L.Z.; Yun, C.; Zhao, H.; Zhang, X.F.; Wang, C.S.; Yang, Y.C.; Yang, J.B.

    2014-01-01

    The heterostructural junctions of CeO 2 /La 0.7 (Sr 0.1 Ca 0.9 ) 0.3 MnO 3 /Pt (CeO 2 /LSCMO/Pt) were prepared using pulse laser deposition technique. Their resistive switching (RS) behavior was investigated. As compared to the metal/manganite/Pt junction, the CeO 2 /LSCMO/Pt device displayed an improved switching characteristic. The RS effects with characteristics of bipolar, threshold, and complementary were realized by adjusting the thicknesses of the CeO 2 layer in the CeO 2 /LSCMO/Pt junctions. Under a higher external bias voltage, the threshold and complementary switching modes of the junctions could turn into bipolar switching mode. The switching behavior shows strong dependence on the O 2 partial pressure during the fabrication, indicating that the amount and behavior of the oxygen at the interface play an important role in the determination of the RS behavior. The observed switching behavior is related to the modification of the accumulation/depletion layers as well as the interfacial potential barrier due to the migration of the oxygen vacancies. - Highlights: • Heterostructure of CeO 2 /LSMO/Pt displayed an improved resistance switching characteristic. • Resistance switching with characteristics of bipolar, threshold and complementary was found. • Threshold and complementary switching mode could turn into bipolar switching mode. • Switching behavior is related to the modification of the accumulation/depletion layers. • Interfacial potential barrier due to the migration of oxygen vacancies was proposed

  15. Inhaled 239PuO2 and/or total-body gamma radiation: Early mortality and morbidity in rats and dogs

    International Nuclear Information System (INIS)

    Filipy, R.E.; Decker, J.R.; Lai, Y.L.

    1988-08-01

    Rats and beagle dogs were given doses of 60 Co gamma radiation and/or body burdens of 239 PuO 2 within lethal ranges in an experiment to determine and compare morbidity and mortality responses of both species within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell concentrations and by long-term loss of body weight and diminished pulmonary function in animals of both species that survived the acute gamma radiation syndrome. Inhaled plutonium caused a loss of body weight and diminished pulmonary function in both species, but its only effect on blood cell concentrations was lymphocytopenia in dogs. Combined gamma irradiation and plutonium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Plutonium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the long-term effect of plutonium lung burdens in both species. Rats were less sensitive to both kinds of radiation, whether administered alone or in combination. 71 refs., 105 figs., 48 tabs

  16. Use of a pulsed neutron generator for in vivo measurement of body carbon

    International Nuclear Information System (INIS)

    Kehayias, J.J.; Ellis, K.J.; Cohn, S.H.; Yasumura, S.

    1986-01-01

    The measurement of total body fat is of importance in studies of nutritional assessment, dietary regimens, and for the management of obesity. In the past, fat has been determined either by anthropometric methods, which introduce high uncertainties, or by model-dependent estimation of fat-free tissue. The validity, however, of the different models in disease is questionable. Total body carbon measurements provide a more direct evaluation of body fat both in normal subjects and in patients. The authors present here a facility for carbon measurements without the use of a major accelerator. The same facility can be used for the measurement of other major body elements and for the evaluation of the body's compartments. Carbon is measured in vivo through neutron inelastic scattering, by detecting the 4.44 MeV gamma rays. A miniature (10 cm long) 14 MeV D-T neutron generator is used. The short half-life of the 4.44 MeV state of carbon requires detection of the gamma rays simultaneously with the 10 μs neutron pulse. Generators with low pulsing rate were found inappropriate for carbon measurement because of their low duty-cycle (high neutron output during pulse). The detection system consists of NaI(T1) detectors and fast electronics for handling the high even rate during the neutron pulse. A description of the facility and an evaluation of the technique will be presented

  17. Repeatability of pulse diagnosis and body constitution diagnosis in traditional Indian Ayurveda medicine

    DEFF Research Database (Denmark)

    Kurande, Vrinda; Waagepetersen, Rasmus; Toft, Egon

    2012-01-01

    In Ayurveda, pulse and body constitution diagnosis have a long historical use; still there is lack of quantitative measure on e.g. reliability of this diagnostic method. Reliability means consistency of information. Consistent diagnosis leads to consistent treatment and is important for clinical ...

  18. High quantum efficiency annular backside silicon photodiodes for reflectance pulse oximetry in wearable wireless body sensors

    DEFF Research Database (Denmark)

    Duun, Sune Bro; Haahr, Rasmus Grønbek; Hansen, Ole

    2010-01-01

    The development of annular photodiodes for use in a reflectance pulse oximetry sensor is presented. Wearable and wireless body sensor systems for long-term monitoring require sensors that minimize power consumption. We have fabricated large area 2D ring-shaped silicon photodiodes optimized...

  19. Evaluation of a Novel HA/ZrO2-Based Porous Bioceramic Artificial Vertebral Body Combined with a rhBMP-2/Chitosan Slow-Release Hydrogel.

    Directory of Open Access Journals (Sweden)

    Yihui Shi

    Full Text Available A new HA/ZrO2-based porous bioceramic artificial vertebral body (AVB, carried a recombinant human bone morphogenetic protein-2 (rhBMP-2/chitosan slow-release hydrogel was prepared to repair vertebral bone defect in beagles. An ionic cross-linking was used to prepare the chitosan hydrogel (CS gel as the rhBMP-2 slow-release carrier. The vertebral body defects were implanted with the rhBMP-2-loaded AVB in group A, or a non-drug-loaded AVB in group B, or autologous iliac in group C. The encapsulation rate of rhBMP-2 in rhBMP-2-loaded CS gel was 91.88±1.53%, with a drug load of 39.84±2.34 ng/mg. At 6, 12, 24 weeks postoperatively, radiography showed that the bone calluses gradually increased with time in group A, where the artificial vertebral body had completely fused with host-bone at 24 weeks after surgery. In group C, an apparent bone remodeling was occurred in the early stages, and the graft-bone and host-bone had also fused completely at 24 weeks postoperatively. In group B, fusion occurred less than in groups A and C. At 24 weeks after surgery, micro-computed tomography (Micro-CT revealed that the volume of newly-formed bone in group A was significantly more than in group B (p<0.05. At 24 weeks after surgery, ultra-compressive strengths of the operated segments were 14.03±1.66 MPa in group A, 8.62±1.24 MPa in group B, and 13.78±1.43 MPa in group C. Groups A and C were both significantly higher than group B (p < 0.05. At 24 weeks postoperatively, the hard tissue sections showed that the AVB of group A had tightly fused with host bone, and that pores of the AVB had been filled with abundant nearly mature bone, and that the new bone structured similarly to a trabecular framework, which was similar to that in group C. In contrast, implant fusion of the AVB in group B was not as apparent as group A. In conclusion, the novel HA/ZrO2-based porous bioceramic AVB carried the rhBMP-2-loaded CS gel can promote the repair of bony defect, and induce

  20. Direct observation of ozone formation on SiO2 surfaces in O2 discharges

    Science.gov (United States)

    Marinov, D.; Guaitella, O.; Booth, J. P.; Rousseau, A.

    2013-01-01

    Ozone production is studied in a pulsed O2 discharge at pressures in the range 1.3-6.7 mbar. Time-resolved absolute concentrations of O3 and O are measured in the post-discharge using UV absorption spectroscopy and two-photon absorption laser-induced fluorescence. In a bare silica discharge tube ozone is formed mainly by three-body gas-phase recombination. When the tube surface is covered by a high specific surface silica catalyst heterogeneous formation becomes the main source of ozone. The efficiency of this surface process increases with O2 pressure and is favoured by the presence of OH groups and adsorbed H2O on the surface. At p = 6.7 mbar ozone production accounts for up to 25% of the atomic oxygen losses on the surface.

  1. Direct observation of ozone formation on SiO2 surfaces in O2 discharges

    International Nuclear Information System (INIS)

    Marinov, D; Guaitella, O; Booth, J P; Rousseau, A

    2013-01-01

    Ozone production is studied in a pulsed O 2 discharge at pressures in the range 1.3-6.7 mbar. Time-resolved absolute concentrations of O 3 and O are measured in the post-discharge using UV absorption spectroscopy and two-photon absorption laser-induced fluorescence. In a bare silica discharge tube ozone is formed mainly by three-body gas-phase recombination. When the tube surface is covered by a high specific surface silica catalyst heterogeneous formation becomes the main source of ozone. The efficiency of this surface process increases with O 2 pressure and is favoured by the presence of OH groups and adsorbed H 2 O on the surface. At p = 6.7 mbar ozone production accounts for up to 25% of the atomic oxygen losses on the surface.

  2. Temperature effects on Microalgal Photosynthesis-Light responses measured by O2 production, Pulse-Amplitude-Modulated Fluorescence, and 14C assimilation

    DEFF Research Database (Denmark)

    Hancke, Kasper; Hancke, Torunn; Olsen, Lasse M.

    2008-01-01

    Short-term temperature effects on photosynthesis were investigated by measuring O2 production, PSII-fluorescence kinetics, and 14C-incorporation rates in monocultures of the marine phytoplankton species Prorocentrum minimum (Pavill.) J. Schiller (Dinophyceae), Prymnesium parvum f. patelliferum ( J....... C. Green, D. J. Hibberd et Pienaar) A. Larsen (Coccolithophyceae), and Phaeodactylum tricornutum Bohlin (Bacillariophyceae), grown at 15 oC and 80 umol photons m-2 s-1. Photosynthesis versus irradiance curves were measured at seven temperatures (0oC to 30oC) by all three approaches. The maximum...

  3. Enhanced conductivity in pulsed laser deposited Ce0.9Gd0.1O2−δ/SrTiO3 heterostructures

    DEFF Research Database (Denmark)

    Kant, K. Mohan; Esposito, Vincenzo; Pryds, Nini

    2010-01-01

    Significant enhancement in the electrical conductivity of Ce0.9Gd0.1O2−δ (CGO) thin films (250 and 500 nm) deposited on MgO(001) substrate is observed by introducing ∼ 50 nm thin SrTiO3 buffer layer film. Introduction of the buffer layer is found to form epitaxial films, leading to minimal grain...... boundary network that results in a free conduction path with near-zero blocking effects perpendicular to current flow. The in-plane conductivity measurements confirm increase in conductivity with increase in compressive strain on CGO films. © 2010 American Institute of Physics...

  4. Behaviour of total surface charge in SiO2-Si system under short-pulsed ultraviolet irradiation cycles characterised by surface photo voltage technique

    International Nuclear Information System (INIS)

    Kang, Ban-Hong; Lee, Wah-Pheng; Yow, Ho-Kwang; Tou, Teck-Yong

    2009-01-01

    Effects of time-accumulated ultraviolet (UV) irradiation and surface treatment on thermally oxidized p-type silicon wafers were investigated by using the surface photo voltage (SPV) technique via the direct measurement of the total surface charge, Q SC . The rise and fall times of Q sc curves, as a function of accumulated UV irradiation, depended on the thermal oxide thickness. A simple model was proposed to explain the time-varying characteristics of Q sc based on the UV-induced bond breaking of SiOH and SiH, and photoemission of bulk electrons to wafer surface where O 2 - charges were formed. While these mechanisms resulted in charge variations and hence in Q sc , these could be removed by rinsing the silicon wafers in de-ionized water followed by spin-dry or blow-dry by an ionizer fan. Empirical parameters were used in the model simulations and curve-fitting of Q SC . The simulated results suggested that initial changes in the characteristic behaviour of Q sc were mainly due to the net changes in the positive and negative charges, but subsequently were dominated by the accumulation of O 2 - during the UV irradiation.

  5. Pulse radiolysis of gases

    International Nuclear Information System (INIS)

    Nielsen, O.J.

    1984-04-01

    The pulse radiolysis equipment and technique are described and its relevance to atmospheric chemistry is discussed. Pulse radiolysis of a number of different chemical systems have been used to check the validity of the proposed mechanisms: 1) The hydrogen atom yield in the pulse radiolysis of H 2 was measured by four independent calibration techniques, using reactions of H with O 2 , C1NO, and HI. The H atom yield was compared with O 2 yields in pure O 2 and in O 2 /SF 6 mixtures which lead to a value G(H) = 17.6. The rate constants at room temperature of several reactions were determined. 2) OH radical reactions with tetraalkyllead at room temperature and with ethane, methane, and a series of C1- and F-substituted methanes at 300-400 K were studied. Arrhenius parameters, A and Esub(a), were determined for several reactions. The lifetime of Pb(CH 3 ) 4 and Pb(C 2 H 5 ) 4 in ambient air is estimated. CF 2 C1 2 was found to be a very efficient third body, M, in the reaction OH + OH + M arrow H 2 O 2 + M. 3) In the H 2 S systems the HS extinction coefficient at 3242 AA was determined to 9.5 x 10 2 cm -1 mol -1 . Four rate constants at room temperature were determined. (author)

  6. High quantum efficiency annular backside silicon photodiodes for reflectance pulse oximetry in wearable wireless body sensors

    International Nuclear Information System (INIS)

    Duun, Sune; Haahr, Rasmus G; Hansen, Ole; Birkelund, Karen; Thomsen, Erik V

    2010-01-01

    The development of annular photodiodes for use in a reflectance pulse oximetry sensor is presented. Wearable and wireless body sensor systems for long-term monitoring require sensors that minimize power consumption. We have fabricated large area 2D ring-shaped silicon photodiodes optimized for minimizing the optical power needed in reflectance pulse oximetry. To simplify packaging, backside photodiodes are made which are compatible with assembly using surface mounting technology without pre-packaging. Quantum efficiencies up to 95% and area-specific noise equivalent powers down to 30 fW Hz -1/2 cm -1 are achieved. The photodiodes are incorporated into a wireless pulse oximetry sensor system embedded in an adhesive patch presented elsewhere as 'The Electronic Patch'. The annular photodiodes are fabricated using two masked diffusions of first boron and subsequently phosphor. The surface is passivated with a layer of silicon nitride also serving as an optical filter. As the final process, after metallization, a hole in the center of the photodiode is etched using deep reactive ion etch.

  7. The influence of tested body size upon longitudinal ultrasonic pulse velocity

    International Nuclear Information System (INIS)

    Suarez Antola, R.

    2001-01-01

    Low ultrasonic frequencies are used in nondestructive testing of heterogeneous materials,such as concrete,rocks and timber.When frequencies are low enough,size and shape of tested bodies may influence measured longitudinal pulse velocities(geometric dispersion).A simplified mathematical model is developed from known experimental and theoretical results obtained for elastic wave propagation in rods of uniform circular cross section.Wave propagation is described by a spatial averaged dilatational field in an approach which is named quasi fluid.A formula is obtained which relates group velocity with an effective lateral size of the body,with transducers a frequency,with a non-dimensional parameter and with asymptotic P-wave velocity.In principle it can be applied to bars of any uniform cross section.The limitations of this formula are discussed in relation to path length,threshold of detection,patterns of radiation and reception and other variables.A more general formula is proposed.Practical application of this formula is briefly exemplified using some experimental data obtained by the author.The problem of longitudinal pulse propagation in reinforcing steel bars embedded in concrete is briefly considered

  8. THE EXCITED LOADS OF ATTRACTION IN A SYMMETRICAL INDUCTOR SYSTEM FOR THE MAGNETIC PULSE REMOVING OF THE BODY CAR

    Directory of Open Access Journals (Sweden)

    A. V. Gnatov

    2015-04-01

    Full Text Available Recently, repair and recovery of vehicle body operations become more and more popular. A special place here is taken by equipment that provides performance of given repair operations. The most interesting are methods for recovery of car body panels that allow the straightening without disassembling of car body panels and damaging of existing protective coating. Now, there are several technologies for repair and recovery of car body panels without their disassembly and dismantling. The most perspective is magnetic-pulse technology of external noncontact straightening. Results. The calculation of excited loads attractions in a symmetrical inductor system in the universal tool of magnetic-pulse straightening is provided. According to the obtained analytical dependence of the numerical evaluation of volumetric construction diagrams, phase and amplitude of the radial dependence of the spatial distribution of the excited efforts of attraction is obtained. The influence of the magnetic properties of the blank screen and manifested in the appearance of powerful magnetic attraction forces is determined. Originality. A new trend of research of magnetic-pulse working of thin-walled metals has been formulated and received further development, which allows to create not only new equipment, but principally new technological processes of external non-contact repair and recovery of vehicle body panels. Scientific basis of electrodynamic and magnetic attraction of thin-walled sheet metals with using the energy of high-power pulsed fields was created for the first time and proved theoretically and experimentally. Scientific and technical solutions in design of effective tools based on single-turn inductor systems of cylindrical geometry for straightening and recovery of car body panels were formulated and proved theoretically, as well as experimentally. Practical value. Using the results of the calculations we can create effective tools for an external magnetic

  9. Corrosion mechanism and model of pulsed DC microarc oxidation treated AZ31 alloy in simulated body fluid

    Energy Technology Data Exchange (ETDEWEB)

    Gu Yanhong, E-mail: ygu2@alaska.edu [Department of Mechanical Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775 (United States); Chen Chengfu [Department of Mechanical Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775 (United States); Bandopadhyay, Sukumar [Department of Mining Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775 (United States); Ning Chengyun [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Zhang Yongjun [Department of Mining Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775 (United States); Guo Yuanjun [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China)

    2012-06-01

    This paper addresses the effect of pulse frequency on the corrosion behavior of microarc oxidation (MAO) coatings on AZ31 Mg alloys in simulated body fluid (SBF). The MAO coatings were deposited by a pulsed DC mode at four different pulse frequencies of 300 Hz, 500 Hz, 1000 Hz and 3000 Hz with a constant pulse ratio. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were used for corrosion rate and electrochemical impedance evaluation. The corroded surfaces were examined by X-ray diffraction (XRD), X-ray fluorescence (XRF) and optical microscopy. All the results exhibited that the corrosion resistance of MAO coating produced at 3000 Hz is superior among the four frequencies used. The XRD spectra showed that the corrosion products contain hydroxyapatite, brucite and quintinite. A model for corrosion mechanism and corrosion process of the MAO coating on AZ31 Mg alloy in the SBF is proposed.

  10. Corrosion mechanism and model of pulsed DC microarc oxidation treated AZ31 alloy in simulated body fluid

    International Nuclear Information System (INIS)

    Gu Yanhong; Chen Chengfu; Bandopadhyay, Sukumar; Ning Chengyun; Zhang Yongjun; Guo Yuanjun

    2012-01-01

    This paper addresses the effect of pulse frequency on the corrosion behavior of microarc oxidation (MAO) coatings on AZ31 Mg alloys in simulated body fluid (SBF). The MAO coatings were deposited by a pulsed DC mode at four different pulse frequencies of 300 Hz, 500 Hz, 1000 Hz and 3000 Hz with a constant pulse ratio. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were used for corrosion rate and electrochemical impedance evaluation. The corroded surfaces were examined by X-ray diffraction (XRD), X-ray fluorescence (XRF) and optical microscopy. All the results exhibited that the corrosion resistance of MAO coating produced at 3000 Hz is superior among the four frequencies used. The XRD spectra showed that the corrosion products contain hydroxyapatite, brucite and quintinite. A model for corrosion mechanism and corrosion process of the MAO coating on AZ31 Mg alloy in the SBF is proposed.

  11. Pulsed magnetization transfer imaging with body coil transmission at 3 Tesla: feasibility and application.

    Science.gov (United States)

    Smith, Seth A; Farrell, Jonathan A D; Jones, Craig K; Reich, Daniel S; Calabresi, Peter A; van Zijl, Peter C M

    2006-10-01

    Pulsed magnetization transfer (MT) imaging has been applied to quantitatively assess brain pathology in several diseases, especially multiple sclerosis (MS). To date, however, because of the high power deposition associated with the use of short, rapidly repeating MT prepulses, clinical application has been limited to lower field strengths. The contrast-to-noise ratio (CNR) of MT is limited, and this method would greatly benefit from the use of higher magnetic fields and phased-array coil reception. However, power deposition is proportional to the square of the magnetic field and scales with coil size, and MT experiments are already close to the SAR limit at 1.5T even when smaller transmit coils are used instead of the body coil. Here we show that these seemingly great obstacles can be ameliorated by the increased T(1) of tissue water at higher field, which allows for longer maintenance of sufficiently high saturation levels while using a reduced duty cycle. This enables a fast (5-6 min) high-resolution (1.5 mm isotropic) whole-brain MT acquisition with excellent anatomical visualization of gray matter (GM) and white matter (WM) structures, and even substructures. The method is demonstrated in nine normal volunteers and five patients with relapsing remitting MS (RRMS), and the results show a clear delineation of heterogeneous lesions.

  12. Oral administration of O-2 lean, an anti-obesity herbal composition increased 5-HT metabolism, decreased food intake and body weight in overweight rats

    International Nuclear Information System (INIS)

    Bano, F.; Akhtar, N.; Haleem, D.J.

    2012-01-01

    Feeding behavior is complex processes controlled by the neruroendocrine system.5-HT play an important role in regulation of energy balance by suppressing food intake. Depletion of brain serotonin increase feeding behavior and develop obesity. Many serotoninergic compounds are available in market for the management of body weight. 02-Lean is an anti-obesity herbal formulation prepared by combination of different herbs. Oral administration of aqueous suspension of 02-Lean caused a significant decrease in body weight, food intake, and increase in whole brain 5-HT 5HIAA, tryptophan and plasma tryptophan in over weight rats treated with 0.096g/2ml 02-Lean in comparison to control group. (author)

  13. Physico-chemical properties of (U,Ce)O2

    International Nuclear Information System (INIS)

    Yamada, K.; Yamanaka, S.; Katsura, M.

    1998-01-01

    The high-temperature X-ray diffraction analysis of (U,Ce)O 2 with CeO 2 contents ranging from 0 to 20 mol.% CeO 2 was performed to obtain the variation of the linear thermal expansion coefficient with the CeO 2 content. Ultrasonic pulse-echo measurements were also carried out from room temperature to 673 K to estimate the change in the mechanical properties of (U,Ce)O 2 with the CeO 2 content. The variation in the linear thermal expansion coefficient at the low CeO 2 content region is more steep than that expected from the linear thermal expansion coefficient of UO 2 and CeO 2 . The Young's and shear moduli of all (U,Ce)O 2 were found to decrease with rising temperature. This was due to the increase of the bond length accompanied by the thermal expansion. Although the lattice parameter decreased with CeO 2 content, the moduli of (U,Ce)O 2 were found to decrease with increasing CeO 2 content at room temperature. These results show that in the range from 0 to 20 mol.% of CeO 2 , as CeO 2 content increases, the bottom of the potential energy in (U,Ce)O 2 is shallower and broader. (orig.)

  14. A hybrid body technique: does the pulse diagnostic cun guan chi method have Chinese-Tibetan origins?

    Science.gov (United States)

    Hsu, Elisabeth

    2008-01-01

    This article investigates the medieval origins of the main pulse diagnostic method in contemporary Chinese medicine, sometimes known as san bu (three sectors) method, which requires physicians to examine the mai (vessels, vessel movements or pulse) on the wrist at the three locations cun guan chi (inch, gate, foot). The article provides evidence to suggest that this body technique grew out of an earlier Chinese one, the cun chi (inch-foot) method, which appears to have aimed at investigating the qualities of yin and yang in order to determine the condition of a patient by means of exploring fairly large areas of the patient's body surface with the palms. The article furthermore posits that the cun chi method was decisively transformed in medieval times, presumably due to the impact of early Tibetan pulse diagnostic practices: it became framed in a numerology of three and started advocating the use of the fingertips for sensing the pulse beats. The article, which draws on detailed textual analyses of medieval manuscripts, on visual evidence and also on psychophysical research, furthermore highlights how misunderstandings can constructively contribute to cultural communication.

  15. USTUR Whole Body Case 0262: 33-y Follow-up of PuO2 In A Skin Wound and Associated Axillary Node

    Energy Technology Data Exchange (ETDEWEB)

    James, Anthony C.; Sasser, Lyle B.; Stuit, Dorothy B.; Wood, T. G.; Glover, Samuel E.; Lynch, Timothy P.; Dagle, Gerald E.

    2008-01-28

    This whole body donation case (USTUR Registrant) involved two suspected plutonium oxide (Pu) inhalation intakes, each indicated by a measurable Pu alpha activity in a single urine sample, followed about 1.5 y later by a puncture wound to the thumb while working in a Pu glovebox. The study is concerned with modeling simultaneously the biokinetics of deposition and retention in the respiratory tract and at the wound site; and the biokinetics of Pu subsequently transferred to other body organs, until the donor's death. Urine samples taken after the wound incident had readily measurable Pu alpha activity over the next 14 y, before dropping below the minimum detectable excretion rate (<0.4 mBq per day). The Registrant died about 33 y after the wound intake, at the age of 71, from hepatocellular carcinoma with extensive metastases. At autopsy, all major soft tissue organs were harvested for analysis of their Pu-238, Pu-239+240 and Am-241 content. The amount of Pu-239+240 retained at the wound site was 68 ± 7 Bq (1 SD), measured by low-energy planar Ge spectrometry. A further 56.0 ± 1.2 Bq was retained in an associated axillary lymph node, measured by radiochemistry. Simultaneous mathematical analysis (modelling) of all in vivo urinary excretion data, together with the measured lung, thoracic lymph node, wound, axillary lymph node and systemic tissue contents at death, yielded estimated intake amounts of 757 and 1504 Bq, respectively, for the first and second inhalation incidents, and 204 Bq for the total wound intake. The inhaled Pu material was highly insoluble, with an estimated long-term absorption rate from the lungs of 2 E-5 per day. The Pu material deposited at the wound site was mixed: 14% was rapidly absorbed, 49% was absorbed at the rate of about 6E-5 per day, and the remainder ( 37%) was absorbed extremely slowly (at the rate of about 5E-6 per day). Thus, it was estimated that only 40% of the Pu initially deposited in the wound had been absorbed

  16. Comparison of oxygen saturation values and measurement times by pulse oximetry in various parts of the body.

    Science.gov (United States)

    Yönt, Gülendam Hakverdioğlu; Korhan, Esra Akin; Khorshid, Leyla

    2011-11-01

    The aim of this study, which included 40 patients, was to compare the values pulse oximetry and the measurement times in various regions of the body. Data were analyzed using intraclass correlation coefficient test and paired-sample test. The confidence power value was found to be .81 for the comparison of oxygen saturation values by arterial blood gas analysis and measurement by the forehead probe. It was found that the time for oxygen saturation measurement using the forehead probe was shorter than those using the finger and toe probes. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. An analytical model for pulse shape and electrothermal stability in two-body transition-edge sensor microcalorimeters

    International Nuclear Information System (INIS)

    Bennett, D. A.; Horansky, R. D.; Schmidt, D. R.; Swetz, D. S.; Vale, L. R.; Ullom, J. N.; Hoover, A. S.; Hoteling, N. J.; Rabin, M. W.

    2010-01-01

    High-resolution superconducting gamma-ray sensors show potential for the more accurate analysis of nuclear material. These devices are part of a larger class of microcalorimeters and bolometers based on transition edge sensors (TESs) that have two distinct thermal bodies. We derive the time domain behavior of the current and temperature for compound TES devices in the small signal limit and demonstrate the utility of these equations for device design and characterization. In particular, we use the model to fit pulses from our gamma-ray microcalorimeters and demonstrate how critical damping and electrothermal stability can be predicted.

  18. Pulsed neutron generator system for astrobiological and geochemical exploration of planetary bodies

    International Nuclear Information System (INIS)

    Akkurt, Hatice; Groves, Joel L.; Trombka, Jacob; Starr, Richard; Evans, Larry; Floyd, Samuel; Hoover, Richard; Lim, Lucy; McClanahan, Timothy; James, Ralph; McCoy, Timothy; Schweitzer, Jeffrey

    2005-01-01

    A pulsed neutron/gamma-ray detection system for use on rovers to survey the elemental concentrations of Martian and Lunar surface and subsurface materials is evaluated. A robotic survey system combining a pulsed neutron generator (PNG) and detectors (gamma ray and neutron) can measure the major constituents to a depth of about 30 cm. Scanning mode measurements can give the major elemental concentrations while the rover is moving; analyzing mode measurements can give a detailed elemental analysis of the adjacent material when the rover is stationary. A detailed map of the subsurface elemental concentrations will provide invaluable information relevant to some of the most fundamental astrobiological questions including the presence of water, biogenic activity, life habitability and deposition processes

  19. Effect of supply voltage and body-biasing on single-event transient pulse quenching in bulk fin field-effect-transistor process

    International Nuclear Information System (INIS)

    Yu Jun-Ting; Chen Shu-Ming; Chen Jian-Jun; Huang Peng-Cheng; Song Rui-Qiang

    2016-01-01

    Charge sharing is becoming an important topic as the feature size scales down in fin field-effect-transistor (FinFET) technology. However, the studies of charge sharing induced single-event transient (SET) pulse quenching with bulk FinFET are reported seldomly. Using three-dimensional technology computer aided design (3DTCAD) mixed-mode simulations, the effects of supply voltage and body-biasing on SET pulse quenching are investigated for the first time in bulk FinFET process. Research results indicate that due to an enhanced charge sharing effect, the propagating SET pulse width decreases with reducing supply voltage. Moreover, compared with reverse body-biasing (RBB), the circuit with forward body-biasing (FBB) is vulnerable to charge sharing and can effectively mitigate the propagating SET pulse width up to 53% at least. This can provide guidance for radiation-hardened bulk FinFET technology especially in low power and high performance applications. (paper)

  20. Numerical simulation and experiment of high-intensity current pulsed impact on the structure body

    International Nuclear Information System (INIS)

    Li Mintang; Yan Ping; Yuan Weiqun; Sun Yaohong; Sun Lianhua; Zhou Yuan; Liu Chuanpu

    2010-01-01

    To better understand the characteristics of the impulse force formed by pulse current of electromagnetic rail propulsion system, and to explore effective ways to improve the support structure of rails, a set of impulse force test system was designed, and the work-related test situation was numerically simulated. Several impulse force waveforms formed by different pulse current waveforms were achieved by using an armature as a source of impulse force in this test system, and two curves of waveform were comparatively analyzed. The armature existing in the environment of coupling fields including electric field and magnetic field and force field was carried out numerical calculation by using the software of ANSYS, and the coupling force field was emphatically analyzed to calculate the electromagnetic driving force and the electromagnetic clamping force acting on the armature, and the structure stress and deformation was also analyzed. The results showed that the curves of electromagnetic driving force computed by numerical simulation and the curves of impulse force obtained by experiment were basically the same, and the value of peak points' error was increasing along with the increase of pulse current, but the curves still showed some common characteristics. This verified that the test method we used in this paper was proper to capture the impulse force, and the method of calculation was also feasible and effective. (authors)

  1. CeO2-ZrO2 ceramic compounds

    International Nuclear Information System (INIS)

    Melo, F.C.L.; Cairo, C.A.C.; Devezas, T.C.; Nono, M.C.A.

    1988-01-01

    In order to study the mechanical properties of tetragonal polycrystal zirconia stabilized with ceria various powder compositions with different CeO 2 content were made. Modulus of rupture for those compounds was measured. Tetragonal retained phase was determined for samples of CeO 2 -ZrO 2 ceramics with and without superficial mechanical treatment. The experimental results allowed us to evaluate the effects of CeO 2 content and sintering temperature in the mechanical properties and tetragonal transformed phase (t→ m) in ceramics of CeO 2 -ZrO 2 systems. (author) [pt

  2. Plasma plume effects on the conductivity of amorphous-LaAlO3/SrTiO3 interfaces grown by pulsed laser deposition in O2 and Ar

    DEFF Research Database (Denmark)

    Sambri, A.; Christensen, Dennis; Trier, Felix

    2012-01-01

    Amorphous-LaAlO3/SrTiO3 interfaces exhibit metallic conductivity similar to those found for the extensively studied crystalline-LaAlO3/SrTiO3 interfaces. Here, we investigate the conductivity of the amorphous-LaAlO3/SrTiO3 interfaces grown in different pressures of O2 and Ar background gases...

  3. Transient interaction model of electromagnetic field generated by lightning current pulses and human body

    International Nuclear Information System (INIS)

    Iváncsy, T; Kiss, I; Tamus, Z Á; Szücs, L

    2015-01-01

    The lightning current generates time-varying magnetic field near the down-conductor and the down-conductors are mounted on the wall of the buildings where residential places might be situated. It is well known that the rapidly changing magnetic fields can generate dangerous eddy currents in the human body.The higher duration and gradient of the magnetic field can cause potentially life threatening cardiac stimulation. The coupling mechanism between the electromagnetic field and the human body is based on a well-known physical phenomena (e.g. Faradays law of induction). However, the calculation of the induced current is very complicated because the shape of the organs is complex and the determination of the material properties of living tissues is difficult, as well. Our previous study revealed that the cardiac stimulation is independent of the rising time of the lightning current and only the peak of the current counts.In this study, the authors introduce an improved model of the interaction of electromagnetic fields of lighting current near down-conductor and human body. Our previous models are based on the quasi stationer field calculations, the new improved model is a transient model. This is because the magnetic field around the down-conductor and in the human body can be determined more precisely, therefore the dangerous currents in the body can be estimated. (paper)

  4. O2(a1Δ) Quenching In The O/O2/O3 System

    Science.gov (United States)

    Azyazov, V. N.; Mikheyev, P. A.; Postell, D.; Heaven, M. C.

    2010-10-01

    The development of discharge singlet oxygen generators (DSOG's) that can operate at high pressures is required for the power scaling of the discharge oxygen iodine laser. In order to achieve efficient high-pressure DSOG operation it is important to understand the mechanisms by which singlet oxygen (O2(a1Δ)) is quenched in these devices. It has been proposed that three-body deactivation processes of the type O2(a1Δ)+O+M→2O2+M provide significant energy loss channels. To further explore these reactions the physical and reactive quenching of O2(a1Δ) in O(3P)/O2/O3/CO2/He/Ar mixtures has been investigated. Oxygen atoms and singlet oxygen molecules were produced by the 248 nm laser photolysis of ozone. The kinetics of O2(a1Δ) quenching were followed by observing the 1268 nm fluorescence of the O2a1Δ-X3∑ transition. Fast quenching of O2(a1Δ) in the presence of oxygen atoms and molecules was observed. The mechanism of the process has been examined using kinetic models, which indicate that quenching by vibrationally excited ozone is the dominant reaction.

  5. O2(a1Δ) Quenching In The O/O2/O3 System

    International Nuclear Information System (INIS)

    Azyazov, V. N.; Mikheyev, P. A.; Postell, D.; Heaven, M. C.

    2010-01-01

    The development of discharge singlet oxygen generators (DSOG's) that can operate at high pressures is required for the power scaling of the discharge oxygen iodine laser. In order to achieve efficient high-pressure DSOG operation it is important to understand the mechanisms by which singlet oxygen (O 2 (a 1 Δ)) is quenched in these devices. It has been proposed that three-body deactivation processes of the type O 2 (a 1 Δ)+O+M→2O 2 +M provide significant energy loss channels. To further explore these reactions the physical and reactive quenching of O 2 (a 1 Δ) in O( 3 P)/O 2 /O 3 /CO 2 /He/Ar mixtures has been investigated. Oxygen atoms and singlet oxygen molecules were produced by the 248 nm laser photolysis of ozone. The kinetics of O 2 (a 1 Δ) quenching were followed by observing the 1268 nm fluorescence of the O 2 a 1 Δ-X 3 Σ transition. Fast quenching of O 2 (a 1 Δ) in the presence of oxygen atoms and molecules was observed. The mechanism of the process has been examined using kinetic models, which indicate that quenching by vibrationally excited ozone is the dominant reaction.

  6. Pulse Waveform and Transcranial Doppler Analysis during Lower Body Negative Pressure

    Science.gov (United States)

    1993-04-01

    26, 23]. The application of negative pressure to the body for scientific or medical purposes was first used in 1841 by Junod , who used it to create a...localized hyperemia [26]. Junod also suggested that it could be used prior to invasive surgical procedures, since the syncope it was able to produce

  7. Endurance Enhancement and High Speed Set/Reset of 50 nm Generation HfO2 Based Resistive Random Access Memory Cell by Intelligent Set/Reset Pulse Shape Optimization and Verify Scheme

    Science.gov (United States)

    Higuchi, Kazuhide; Miyaji, Kousuke; Johguchi, Koh; Takeuchi, Ken

    2012-02-01

    This paper proposes a verify-programming method for the resistive random access memory (ReRAM) cell which achieves a 50-times higher endurance and a fast set and reset compared with the conventional method. The proposed verify-programming method uses the incremental pulse width with turnback (IPWWT) for the reset and the incremental voltage with turnback (IVWT) for the set. With the combination of IPWWT reset and IVWT set, the endurance-cycle increases from 48 ×103 to 2444 ×103 cycles. Furthermore, the measured data retention-time after 20 ×103 set/reset cycles is estimated to be 10 years. Additionally, the filamentary based physical model is proposed to explain the set/reset failure mechanism with various set/reset pulse shapes. The reset pulse width and set voltage correspond to the width and length of the conductive-filament, respectively. Consequently, since the proposed IPWWT and IVWT recover set and reset failures of ReRAM cells, the endurance-cycles are improved.

  8. Synthesis of Fe2O3/TiO2 nanorod-nanotube arrays by filling TiO2 nanotubes with Fe

    International Nuclear Information System (INIS)

    Mohapatra, Susanta K; Banerjee, Subarna; Misra, Mano

    2008-01-01

    Synthesis of hematite (α-Fe 2 O 3 ) nanostructures on a titania (TiO 2 ) nanotubular template is carried out using a pulsed electrodeposition technique. The TiO 2 nanotubes are prepared by the sonoelectrochemical anodization method and are filled with iron (Fe) by pulsed electrodeposition. The Fe/TiO 2 composite is then annealed in an O 2 atmosphere to convert it to Fe 2 O 3 /TiO 2 nanorod-nanotube arrays. The length of the Fe 2 O 3 inside the TiO 2 nanotubes can be tuned from 50 to 550 nm by changing the deposition time. The composite material is characterized by scanning electron microscopy, transmission electron microscopy and diffuse reflectance ultraviolet-visible studies to confirm the formation of one-dimensional Fe 2 O 3 /TiO 2 nanorod-nanotube arrays. The present approach can be used for designing variable one-dimensional metal oxide heterostructures

  9. The volume of the carotid bodies and blood pressure variability and pulse pressure in patients with essential hypertension

    International Nuclear Information System (INIS)

    Jaźwiec, P.; Gać, P.; Poręba, M.; Sobieszczańska, M.; Mazur, G.; Poręba, R.

    2016-01-01

    Aim: To assess the relationship between the volume of the carotid bodies (V rCB+lCB ) examined by means of computed tomography angiography (CTA) and blood pressure variability and pulse pressure (PP) in 24-hour ambulatory blood pressure monitoring (ABPM) in patients with essential hypertension. Materials and methods: A group of 52 patients with essential hypertension was examined (mean age: 68.32±12.31 years), the sizes of carotid bodies were measured by means of carotid artery CTA, and 24-hour ABPM was carried out. The 24-hour ABPM established systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), PP, SBP variability (SBPV), and DBP variability (DBPV). Results: SBP, MAP, and SBPV were significantly higher in the group of hypertension patients with V rCB+lCB equal to or above the median than in the group of hypertension patients with V rCB+lCB less than the median, as well as in the group of hypertension patients with oversized carotid bodies, than in the group of hypertension patients with normal V rCB+lCB . Moreover, the PP was statistically significantly higher in the group of hypertension patients with V rCB+lCB equal to or above the median than in the group of hypertension patients with V rCB+lCB less than the median. The existence of statistically significant positive linear relationships was revealed between V rCB+lCB and SBP, PP, and SBPV. A higher body mass index, older age, smoking, and higher V rCB+lCB are independent risk factors increasing SBPV in the research group. Conclusion: A positive relationship between the size of the carotid bodies and variability of the SBP and PP is observed in patients with essential hypertension. - Highlights: • Purpose. Determination of the relationships: V rCB+lCB vs. BPV and V rCB+lCB vs. PP. • Positive linear correlations were documented between V rCB+lCB and SBP, PP and SBPV. • Higher BMI, age, V rCB+lCB and smoking are independent risk factor of increased SBPV.

  10. Comparison of Three Popular Exercise Modalities on V˙O2max in Overweight and Obese.

    Science.gov (United States)

    Bækkerud, Fredrik Hjulstad; Solberg, Frederic; Leinan, Ingeborg Megård; Wisløff, Ulrik; Karlsen, Trine; Rognmo, Øivind

    2016-03-01

    In this prospective randomized trial, we examined the effect of three popular exercise training modalities on maximal oxygen uptake (V˙O2max) in overweight and obese individuals. In addition, we examined possible concomitant adaptations in endurance exercise performance (time to exhaustion (TTE)), citrate synthase (CS) activity, venous and arterial function, blood volume, and calculated stroke volume (SV). Thirty subjects were recruited (age, 41 ± 9 yr; weight, 91 ± 14 kg; height, 173 ± 8 cm; body mass index, 30 ± 4 kg·m(-2)) and randomized to either 6 wk of 4 × 4-min high-intensity interval training (4HIIT) at 85%-95% of HRmax, 10 × 1-min HIIT (1HIIT) at V˙O2max load, or 45-min moderate-intensity continuous training (MICT) at 70% of HRmax. V˙O2max, TTE, CS activity, venous and arterial function, as well as blood volume were measured before and after the training period. O2 pulse was calculated and used to estimate SV. Analysis was conducted per protocol. Only 4HIIT increased V˙O2max (P HIIT (P = 0.04) and MICT (P = 0.03) (4HIIT, 10%; 1HIIT, 3.3%; and MICT, 3.1%). All groups increased TTE (4HIIT, 198%; 1HIIT, 116%; MICT, 52%), with a higher increase after 4HIIT compared with that after MICT (P = 0.02). Calculated SV increased only after 4HIIT (14.4%). Plasma volume and hemoglobin mass increased after 1HIIT only (5.6% and 6.5%); however, no group differences were found. All groups increased CS activity (4HIIT, 35%; 1HIIT, 35%; MICT, 56%), with no group differences. Arterial inflow (15.7%) and venous outflow (22.7%) decreased after MICT, but there were no group differences. 4HIIT was superior to 1HIIT and MICT in improving V˙O2max likely because of an increased SV.

  11. Relative Humidity of 40% Inhibiting the Increase of Pulse Rate, Body Temperature, and Blood Lactic Acid During Exercise

    Directory of Open Access Journals (Sweden)

    Nengah Sandi

    2016-05-01

    Full Text Available Background: Excessive sweating of the body is a reaction to decrease the heat caused by prolonged exercise at high relative humidity (RH. This situation may cause an increase in pulse rate (PR, body temperature (BT, and blood lactic acid (BLA workout. Objective: This study aimed to prove that a RH of 40% better than a RH of 50% and 60% RH in inhibiting the increase of PR, BT, and BLA during exercise. Methods: The study was conducted on 54 samples randomly selected from the IKIP PGRI Bali students. The samples were divided into three groups, and each group was given cycling exercise with a load of 80 Watt for 2 x 30 minutes with rest between sets for five minutes. Group-1 of cycling at 40% of RH, Group-2 at a RH of 50%, and the Group-3 at a RH of 60%. Data PR, BT, and BLA taken before and during exercise. The mean difference between groups before and during exercise were analyzed by One-way Anova and a further test used Least Significant Difference (LSD. Significance used was α = 0.05. Results: The mean of PR during exercise was significantly different between groups with p = 0.045, the mean of BT during exercises was significantly different between groups with p = 0.006, and the mean of BLA during exercises was significantly different between groups with p = 0.005 (p <0.05. Also found that PR, BT, and BLA during exercise at 40% RH was lower than 50% RH and 60% RH (p <0.05. Conclusion: Thus, the RH of 40% was better than RH of 50% and 60 % in inhibiting the increase of PR, BT, and BLA during exercise. Therefore, when practiced in a closed room is expected at 40% relative humidity.

  12. Extremum seeking to control the amplitude and frequency of a pulsed jet for bluff body drag reduction

    Science.gov (United States)

    Brackston, Rowan D.; Wynn, Andrew; Morrison, Jonathan F.

    2016-10-01

    Feedback control of fluid flows presents a challenging problem due to nonlinear dynamics and unknown optimal operating conditions. Extremum seeking control presents a suitable method for many flow control situations but involves its own challenges. In this paper, we provide a brief analysis of the extremum seeking method, with attention to modifications that we find to be advantageous. In particular, we present an adaptation for optimisation of the frequency of a harmonic input signal, a common scenario for open-loop flow control systems. We then present results from the experimental implementation of our modified method to the open-loop control system of Oxlade et al. (J Fluid Mech 770:305-318, 2015), an axisymmetric bluff-body wake, forced by a pulsed jet. We find that the system is able to achieve optimal operating conditions in both the amplitude and frequency of the harmonic input signal, and is able to largely reject the disturbances arising from measurements of a highly turbulent flow. We finally show the ability of the extremum seeking system to adapt to changing conditions.

  13. Role of yttria-stabilized zirconia produced by ion-beam-assisted deposition on the properties of RuO2 on SiO2/Si

    International Nuclear Information System (INIS)

    Jia, Q.X.; Arendt, P.; Groves, J.R.; Fan, Y.; Roper, J.M.; Foltyn, S.R.

    1998-01-01

    Highly conductive biaxially textured RuO 2 thin films were deposited on technically important SiO 2 /Si substrates by pulsed laser deposition, where yttria-stabilized zirconia (YSZ) produced by ion-beam-assisted-deposition (IBAD) was used as a template to enhance the biaxial texture of RuO 2 on SiO 2 /Si. The biaxially oriented RuO 2 had a room-temperature resistivity of 37 μΩ-cm and residual resistivity ratio above 2. We then deposited Ba 0.5 Sr 0.5 TiO 3 thin films on RuO 2 /IBAD-YSZ/SiO 2 /Si. The Ba 0.5 Sr 0.5 TiO 3 had a pure (111) orientation normal to the substrate surface and a dielectric constant above 360 at 100 kHz. copyright 1998 Materials Research Society

  14. O2(a1Δ) quenching in O/O2/O3/CO2/He/Ar mixtures

    Science.gov (United States)

    Azyazov, V. N.; Mikheyev, P. A.; Postell, D.; Heaven, M. C.

    2010-02-01

    The development of discharge singlet oxygen generators (DSOG's) that can operate at high pressures is required for the power scaling of the discharge oxygen iodine laser. In order to achieve efficient high-pressure DSOG operation it is important to understand the mechanisms by which singlet oxygen (O2(a1Δ)) is quenched in these devices. It has been proposed that three-body deactivation processes of the type O2(a1Δ))+O+M-->2O2+M provide significant energy loss channels. To further explore these reactions the physical and reactive quenching of O2(a1Δ)) in O(3P)/O2/O3/CO2/He/Ar mixtures has been investigated. Oxygen atoms and singlet oxygen molecules were produced by the 248 nm laser photolysis of ozone. The kinetics of O2(a1Δ)) quenching were followed by observing the 1268 nm fluorescence of the O2 a1Δ-X3Ε transition. Fast quenching of O2(a1Δ)) in the presence of oxygen atoms and molecules was observed. The mechanism of the process has been examined using kinetic models, which indicate that quenching by vibrationally excited ozone is the dominant reaction.

  15. Graphene oxide-MnO2 nanocomposite for supercapacitor application

    Science.gov (United States)

    Muhammed Shafi, P.; Vishal, Jose K.; Chandra Bose, A.

    2016-09-01

    Increased depletion of fossil fuels along with global warming and climate change made the society to think about alternate green and sustainable energy sources and better energy storage devices. Extensive research has been performed on the development of solar cells, fuel cells, Lithium- ion battery and supercapacitors to combat the green house effect and its consequences, and to meet the increased energy crisis. Supercapacitors, also known as electrochemical capacitors are gained a great attention because of their pulse power supply, long cycle life (>100,000), simple principle and high dynamic of charge propagation. Its greater power density than lithium- ion battery and much larger energy density than conventional capacitors brought super capacitors to a promising energy storage device to meet the increased energy demands. Here we demonstrate supercapacitor electrode materials with graphene oxide (electric double layer capacitor) and α-MnO2 nanomaterial (pseudo-capacitor), as well as composite of these materials, which means that the bulk of the material undergoes a fast redox reaction to provide the capacitive response and they exhibit superior specific energies in addition to the carbon-based supercapacitors (double-layer capacitors). A simple soft chemical route is utilized to synthesize graphene oxide, α-MnO2 and graphene oxide-MnO2 composite. The phase and the structure of the synthesized materials are studied using X-ray diffractometry (XRD). The functional group and the presence of impurities are understood from Fourier transform infrared (FTIR) spectra. The capacitive properties of the graphene oxide, graphene oxide - MnO2 nanocomposite and α-MnO2 are tested with the help of cyclic voltammetry (CV) and galvanostatic charge - discharge techniques using 1 M Na2SO4 in aqueous solution as electrolyte. It was found that graphene oxide - MnO2 nanocomposite shows better electrochemical behaviour compared to individual graphene oxide and α-MnO2 nanomaterial.

  16. Tailored TiO2(110) surfaces and their reactivity

    International Nuclear Information System (INIS)

    Pang, C L; Bikondoa, O; Humphrey, D S; Papageorgiou, A C; Cabailh, G; Ithnin, R; Chen, Q; Muryn, C A; Onishi, H; Thornton, G

    2006-01-01

    Electron bombardment from a filament as well as voltage pulses from a scanning tunnelling microscope tip have been employed to modify the surface of TiO 2 (110). Individual H atoms are selectively desorbed with electrical pulses of +3 V from the scanning tunnelling microscope tip, whilst leaving the oxygen vacancies intact. This allows us to distinguish between oxygen vacancies and hydroxyl groups, which have a similar appearance in scanning tunnelling microscopy images. This then allows the oxygen vacancy-promoted dissociation of water and O 2 to be followed with the microscope. Electrical pulses between +5 and +10 V induce local TiO 2 (110)1 x 2 reconstructions centred around the pulse. As for electron bombardment of the surface, relatively low fluxes increase the density of oxygen vacancies whilst higher fluxes lead to the 1 x 2 and other 1 x n reconstructions

  17. Formation of qualified BaHfO3 doped Y0.5Gd0.5Ba2Cu3O7-δ film on CeO2 buffered IBAD-MgO tape by self-seeding pulsed laser deposition

    Science.gov (United States)

    Liu, Linfei; Wang, Wei; Yao, Yanjie; Wu, Xiang; Lu, Saidan; Li, Yijie

    2018-05-01

    Improvement in the in-filed transport properties of REBa2Cu3O7-δ (RE = rare earth elements, REBCO) coated conductor is needed to meet the performance requirements for various practical applications, which can be accomplished by introducing artificial pinning centers (APCs), such as second phase dopant. However, with increasing dopant level the critical current density Jc at 77 K in zero applied magnetic field decreases. In this paper, in order to improve Jc we propose a seed layer technique. 5 mol% BaHfO3 (BHO) doped Y0.5Gd0.5Ba2Cu3O7-δ (YGBCO) epilayer with an inserted seed layer was grown on CeO2 buffered ion beam assisted deposition MgO (IBAD-MgO) tape by pulsed laser deposition. The effect of the conditions employed to prepare the seed layer, including tape moving speed and chemical composition, on the quality of 5 mol% BHO doped YGBCO epilayer was systematically investigated by X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM) observations. It was found that all the samples with seed layer have higher Jc (77 K, self-field) than the 5 mol% BHO doped YGBCO film without seed layer. The seed layer could inhibit deterioration of the Jc at 77 K and self-filed. Especially, the self-seed layer (5 mol% BHO doped YGBCO seed layer) was more effective in improving the crystal quality, surface morphology and superconducting performance. At 4.2 K, the 5 mol% BHO doped YGBCO film with 4 nm thick self-seed layer had a very high flux pinning force density Fp of 860 GN/m3 for B//c under a 9 T field, and more importantly, the peak of the Fp curve was not observed.

  18. Electrochemical Behavior of TiO2 Nanoparticle Doped WO3 Thin Films

    Directory of Open Access Journals (Sweden)

    Suvarna R. Bathe

    2014-01-01

    Full Text Available Nanoparticle TiO2 doped WO3 thin films by pulsed spray pyrolysis technique have been studied on fluorine tin doped (FTO and glass substrate. XRD shows amorphous nature for undoped and anatase phase of TiO2 having (101 plane for nanoparticle TiO2 doped WO3 thin film. SEM shows microfibrous reticulated porous network for WO3 with 600 nm fiber diameter and nanocrystalline having size 40 nm for TiO2 nanoparticle doped WO3 thin film. TiO2 nanoparticle doped WO3 thin film shows ~95% reversibility due to may be attributed to nanocrystalline nature of the film, which helpful for charge insertion and deinsertion process. The diffusion coefficient for TiO2 nanoparticle doped WO3 film is less than undoped WO3.

  19. Associations between body mass index, ambulatory blood pressure findings, and changes in cardiac structure: relevance of pulse and nighttime pressures.

    NARCIS (Netherlands)

    Fedecostante, M.; Spannella, F.; Giulietti, F.; Espinosa, E.; Dessi-Fulgheri, P.; Sarzani, R.

    2015-01-01

    Ambulatory blood pressure monitoring (ABPM) is central in the management of hypertension. Factors related to BP, such as body mass index (BMI), may differently affect particular aspects of 24-hour ABPM profiles. However, the relevance of BMI, the most used index of adiposity, has been

  20. Chemisorption studies of Pt/SnO2 catalysts

    Science.gov (United States)

    Brown, Kenneth G.; Ohorodnik, Susan K.; Vannorman, John D.; Schryer, Jacqueline; Upchurch, Billy T.; Schryer, David R.

    1990-01-01

    The low temperature CO oxidation catalysts that are being developed and tested at NASA-Langley are fairly unique in their ability to efficiently oxidize CO at low temperatures (approx. 303 K). The bulk of the reaction data that has been collected in the laboratory has been determined using plug flow reactors with a low mass of Pt/SnO2/SiO2 catalyst (approx. 0.1 g) and a modest flow rate (5 to 10 sc sm). The researchers have previously characterized the surface solely in terms of N2 BET surface areas. These surface areas have not been that indicative of reaction rate. Indeed, some of the formulations with high BET surface area have yielded lower reaction rates than those with lower BET surface areas. As a result researchers began a program of determining the chemisorption of the various species involved in the reaction; CO, O2 and CO2. Such a determination of will lead to a better understanding of the mechanism and overall kinetics of the reaction. The pulsed-reactor technique, initially described by Freel, is used to determine the amount of a particular molecule that is adsorbed on the catalyst. Since there is some reaction of CO with the surface to produce CO2, the pulsed reactor had to be coupled with a gas chromatograph in order to distinguish between the loss of CO that is due to adsorption by the surface and the loss that is due to reaction with the surface.

  1. SU-E-T-501: Normal Tissue Toxicities of Pulsed Low Dose Rate Radiotherapy and Conventional Radiotherapy: An in Vivo Total Body Irradiation Study

    Energy Technology Data Exchange (ETDEWEB)

    Cvetkovic, D; Zhang, P; Wang, B; Chen, L; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2014-06-01

    Purpose: Pulsed low dose rate radiotherapy (PLDR) is a re-irradiation technique for therapy of recurrent cancers. We have previously shown a significant difference in the weight and survival time between the mice treated with conventional radiotherapy (CRT) and PLDR using total body irradiation (TBI). The purpose of this study was to investigate the in vivo effects of PLDR on normal mouse tissues.Materials and Methods: Twenty two male BALB/c nude mice, 4 months of age, were randomly assigned into a PLDR group (n=10), a CRT group (n=10), and a non-irradiated control group (n=2). The Siemens Artiste accelerator with 6 MV photon beams was used. The mice received a total of 18Gy in 3 fractions with a 20day interval. The CRT group received the 6Gy dose continuously at a dose rate of 300 MU/min. The PLDR group was irradiated with 0.2Gyx20 pulses with a 3min interval between the pulses. The mice were weighed thrice weekly and sacrificed 2 weeks after the last treatment. Brain, heart, lung, liver, spleen, gastrointestinal, urinary and reproductive organs, and sternal bone marrow were removed, formalin-fixed, paraffin-embedded and stained with H and E. Morphological changes were observed under a microscope. Results: Histopathological examination revealed atrophy in several irradiated organs. The degree of atrophy was mild to moderate in the PLDR group, but severe in the CRT group. The most pronounced morphological abnormalities were in the immune and hematopoietic systems, namely spleen and bone marrow. Brain hemorrhage was seen in the CRT group, but not in the PLDR group. Conclusions: Our results showed that PLDR induced less toxicity in the normal mouse tissues than conventional radiotherapy for the same dose and regimen. Considering that PLDR produces equivalent tumor control as conventional radiotherapy, it would be a good modality for treatment of recurrent cancers.

  2. Optical properties of a HfO2/Si stack with a trace amount of nitrogen incorporation

    Science.gov (United States)

    Ye, Li; Tingting, Jiang; Qingqing, Sun; Pengfei, Wang; Shijin, Ding; Wei, Zhang

    2012-03-01

    HfO2 films were deposited by atomic layer deposition through alternating pulsing of Hf[N(C2H5)(CH3)]4 and H2O2. A trace amount of nitrogen was incorporated into the HfO2 through ammonia annealing. The composition, the interface stability of the HfO2/Si stack and the optical properties of the annealed films were analyzed to investigate the property evolution of HfO2 during thermal treatment. With a nitrogen concentration increase from 1.41 to 7.45%, the bandgap of the films decreased from 5.82 to 4.94 eV.

  3. Complex impedance study on nano-CeO2 coating TiO2

    International Nuclear Information System (INIS)

    Zhang Mei; Wang Honglian; Wang Xidong; Li Wenchao

    2006-01-01

    Titanium dioxide (TiO 2 ) nanoparticles and cerium dioxide (CeO 2 ) nanoparticles coated titanium dioxide (TiO 2 ) nanoparticles (CeO 2 -TiO 2 nanoparticles) have been successfully synthesized by sol-gel method. The complex impedance of the materials was investigated. The grain resistance, boundary resistance and activation energy of the nanoparticles were calculated according to Arrhenius equation. According to calculating results, the active capacity of pure TiO 2 nanoparticles has been improved because of nano-CeO 2 coating. An optimal CeO 2 content of 4.9 mol% was achieved. The high resolution electron microscopy images of CeO 2 -TiO 2 nanoparticles showed that TiO 2 nanoparticles, as a core, were covered by CeO 2 nanoparticles. The average size of CeO 2 coating TiO 2 nanoparticles was about 70 nm. Scanning electron microscopy observation indicted that CeO 2 nanoparticle coating improved the separation, insulation, and stability the CeO 2 -TiO 2 nanoparticles, which was benefit to the activity of materials

  4. Preparation and characterization of PbO2–ZrO2 nanocomposite electrodes

    International Nuclear Information System (INIS)

    Yao Yingwu; Zhao Chunmei; Zhu Jin

    2012-01-01

    PbO 2 –ZrO 2 nanocomposite electrodes were prepared by the anodic codeposition in the lead nitrate plating bath containing ZrO 2 nanoparticles. The influences of the ZrO 2 nanoparticles concentration, current density, temperature and stirring rate of the plating bath on the composition of the nanocomposite electrodes were investigated. The surface morphology and the structure of the nanocomposite electrodes were characterized by scanning electronic microscopy (SEM) and X-ray diffraction (XRD), respectively. The experimental results show that the addition of ZrO 2 nanoparticles in the electrodeposition process of lead dioxide significantly increases the lifetime of nanocomposite electrodes. The PbO 2 –ZrO 2 nanocomposite electrodes have a service life of 141 h which is almost four times longer than that of the pure PbO 2 electrodes. The morphology of PbO 2 –ZrO 2 nanocomposite electrodes is more compact and finer than that of PbO 2 electrodes. The relative surface area of the composite electrodes is approximately 2 times that of the pure PbO 2 electrodes. The structure test shows that the addition of ZrO 2 nanoparticles into the plating bath decreases the grain size of the PbO 2 –ZrO 2 nanocomposite electrodes. The anodic polarization curves show that the oxygen evolution overpotential of PbO 2 –ZrO 2 nanocomposite electrodes is higher than PbO 2 electrodes. The pollutant anodic oxidation experiment show that the PbO 2 –ZrO 2 nanocomposite electrode exhibited the better performance for the degradation of 4-chlorophenol than PbO 2 electrode, the removal ratio of COD reached 96.2%.

  5. Synthesis of TiO2-doped SiO2 composite films and its applications

    Indian Academy of Sciences (India)

    Wintec

    structure of the titanium oxide species in the TiO2-doped SiO2 composite films and the photocatalytic reactiv- ity in order to ... gaku D-max γA diffractometer with graphite mono- chromized ... FT–IR absorption spectra of TiO2-doped SiO2 com-.

  6. Improved radiosensitive microcapsules using H2O2

    International Nuclear Information System (INIS)

    Harada, Satoshi; Ehara, Shigeru; Ishii, Keizo

    2010-01-01

    The radiation-induced releasing of the liquid-core of the microcapsules was improved using H 2 O 2 , which produced O 2 generation of H 2 O 2 after irradiation. Further, we tested whether these microcapsules enhanced the antitumor effects and decreased the adverse effects in vivo in C3He/J mice. The capsules were produced by spraying a mixture of 3.0% hyaluronic acid, 2.0% alginate, 3.0% H 2 O 2 , and 0.3 mmol of carboplatin on a mixture of 0.3 mol FeCl 2 and 0.15 mol CaCl 2 . The microcapsules were subcutaneously injected into MM46 tumors that had been inoculated in the left hind legs of C3He/J mice. The radiotherapy comprised tumor irradiation with 10 Gy or 20 Gy 60 Co. The antitumor effect of the microcapsules was tested by measuring tumor size and monitoring tumor growth. Three types of adverse effects were considered: fuzzy hair, loss of body weight, and death. The size of the capsule size was 23±2.4 μmφ and that of the liquid core, 20.2±2.2 μmφ. The injected microcapsules localized drugs around the tumor. The production of O 2 by radiation increased the release of carboplatin from the microcapsules. The antitumor effects of radiation, carboplatin, and released oxygen were synergistic. Localization of the carboplatin decreased its adverse effects. However, the H 2 O 2 caused ulceration of the skin in the treated area. The use of our microcapsules enhanced the antitumor effects and decreased the adverse effects of carboplatin. However, the skin-ulceration caused by H 2 O 2 must be considered before these microcapsules can be used clinically. (author)

  7. Kinetics of the reaction of CH3O2 radicals with NO2

    DEFF Research Database (Denmark)

    Wallington, T.J.; Nielsen, O.J.; Sehested, K.

    1999-01-01

    The kinetics of the gas-phase reaction of CH3O2 radicals with NO2 were studied at 295 K in 0.5-14 arm of SF6 diluent using pulse radiolysis combined with time-resolved UV-VIS spectroscopy. Rate data were obtained by following the loss of CH3O2 using a monitoring wavelength of 260 nm. The results...

  8. Re-evaluation of the reactivity of hydroxylamine with O2-/HO2

    International Nuclear Information System (INIS)

    Bielski, B.H.J.; Arudi, R.L.; Cabelli, D.E.; Bors, W.

    1984-01-01

    The reactivity of hydroxylamine with HO 2 /O 2 - radicals was studied by pulse radiolysis and stopped-flow photolysis over a pH range of 1.1-10.5. Upper limits for the rate of reaction indicate that hydroxylamine, if it reacts at all, reacts at a very slow rate. Its use as an indicator for O 2 - and an assay for superoxide dismutase is, therefore, inappropriate. 20 references, 1 table

  9. Modification of Screen Printed Carbon Electrode (SPCE with Polypyrrole (Ppy-SiO2 for Phenol Determination

    Directory of Open Access Journals (Sweden)

    Ani Mulyasuryani

    2018-01-01

    Full Text Available Electrode modification on screen printed carbon electrode (SPCE with polypyrrole (Ppy-SiO2 was done by electropolymerization. Polypyrrole (Ppy-SiO2 was used for phenol determination. The analysis of this material was done by using Scanning Electron Microscopy (SEM, cyclic voltammetry method and differential pulse voltammetry. In a cyclic voltammetry analysis, we used potential range of -1 to 1 V with Ag/AgCl comparator electrode at scan rate of 100 mV/sec, while in differential pulse voltammetry method the potential range was 0 to 1 V toward Ag/AgCl, the scan rate of 50 mV/sec, the pulse rate is 0,2 V and the pulse width is 50 ms. From the analysis result with SEM, cyclic voltammetry and differential pulse voltammetry method, Polypyrrole (Ppy -SiO2 is the best material and can be used as phenol measurement.

  10. Time resolved Raman studies of laser induced damage in TiO2 optical coatings

    International Nuclear Information System (INIS)

    Exarhos, G.J.; Morse, P.L.

    1984-10-01

    Molecular information available from Raman scattering measurements of sputter deposited TiO 2 on silica substrates has been used to characterize crystalline phases, thickness, and surface homogeneity. A two laser technique is described for investigating transient molecular changes in both coating and substrate which result from pulsed 532 nm laser irradiation. Single layer and multilayer coatings of both anatase and rutile phases of TiO 2 have been probed by Raman spectroscopy immediately following the damage pulse (nanoseconds) and at longer times. Transient measurements are designed to follow surface transformation/relaxation phenomena; measurements at longer times characterize the equilibrium damage state

  11. H2O2: A Dynamic Neuromodulator

    Science.gov (United States)

    Rice, Margaret E.

    2012-01-01

    Increasing evidence implicates hydrogen peroxide (H2O2) as an intra- and intercellular signaling molecule that can influence processes from embryonic development to cell death. Most research has focused on relatively slow signaling, on the order of minutes to days, via second messenger cascades. However, H2O2 can also mediate subsecond signaling via ion channel activation. This rapid signaling has been examined most thoroughly in the nigrostriatal dopamine (DA) pathway, which plays a key role in facilitating movement mediated by the basal ganglia. In DA neurons of the substantia nigra, endogenously generated H2O2 activates ATP-sensitive K+ (KATP) channels that inhibit DA neuron firing. In the striatum, H2O2 generated downstream from glutamatergic AMPA receptor activation in medium spiny neurons acts as a diffusible messenger that inhibits axonal DA release, also via KATP channels. The source of dynamically generated H2O2 is mitochondrial respiration; thus, H2O2 provides a novel link between activity and metabolism via KATP channels. Additional targets of H2O2 include transient receptor potential (TRP) channels. In contrast to the inhibitory effect of H2O2 acting via KATP channels, TRP channel activation is excitatory. This review describes emerging roles of H2O2 as a signaling agent in the nigrostriatal pathway and other basal ganglia neurons. PMID:21666063

  12. Synergistic effects for the TiO2/RuO2/Pt photodissociation of water

    Energy Technology Data Exchange (ETDEWEB)

    Blondel, G; Harriman, A; Williams, D

    1983-07-01

    Compressed discs of naked TiO2 or TiO2 coated with a thin film of a noble metal (e.g. Pt) do not photodissociate water upon illumination with UV light, but small amounts of H2 are generated if the TiO2 has been reduced in a stream of H2 at 600 C. Discs prepared from mixtures of TiO2/RuO2 facilitate the UV photodissociation of water into H2 and O2 although the yields are very low. When a thin (about 9 nm) film of Pt is applied to the TiO2/RuO2 discs, the yields of H2 and O2 observed upon irradiation with UV light are improved drastically. 25 references.

  13. SiO2@TiO2 Coating: Synthesis, Physical Characterization and Photocatalytic Evaluation

    Directory of Open Access Journals (Sweden)

    A. Rosales

    2018-03-01

    Full Text Available Use of silicon dioxide (SiO2 and titanium dioxide (TiO2 have been widely investigated individually in coatings technology, but their combined properties promote compatibility for different innovative applications. For example, the photocatalytic properties of TiO2 coatings, when exposed to UV light, have interesting environmental applications, such as air purification, self-cleaning and antibacterial properties. However, as reported in different pilot projects, serious durability problems, associated with the adhesion between the substrate and TiO2, have been evidenced. Thus, the aim of this work is to synthesize SiO2 together with TiO2 to increase the durability of the photocatalytic coating without affecting its photocatalytic potential. Therefore, synthesis using sonochemistry, synthesis without sonochemistry, physical characterization, photocatalytic evaluation, and durability of the SiO2, SiO2@TiO2 and TiO2 coatings are presented. Results indicate that using SiO2 improved the durability of the TiO2 coating without affecting its photocatalytic properties. Thus, this novel SiO2@TiO2 coating shows potential for developing long-lasting, self-cleaning and air-purifying construction materials.

  14. Reactions UF4 - ClO2F and UF5 - ClO2F

    International Nuclear Information System (INIS)

    Benoit, Raymond; Besnard, Ginette; Hartmanshenn, Olivier; Luce, Michel; Mougin, Jacques; Pelissie, Jean

    1970-02-01

    The study of the reaction UF 4 - ClO 2 F between 0 deg. and 100 deg. C, by various techniques (micro-sublimation, isopiestic method, IR and UV spectrography, thermogravimetry and X-ray diffraction) shows that intermediate steps are possible before the production of UF 5 . The whole reaction may be schematised by two equations: (1) n UF 4 + ClO 2 F → n UF x + ClO 2 (4 4 + ClO 2 F → UF x + 1/2 Cl 2 + O 2 . The more the temperature rises, the more the second equation becomes experimentally verified. The reaction at 0 deg. C between UF 5 and ClO 2 F may be represented by: UF 5 + ClO 2 F → UF 6 ClO 2 . The reactions: UF 5 + ClO 2 F → UF 6 + ClO 2 , UF 5 + ClO 2 F → UF 6 + 1/2 Cl 2 + O 2 are verified, the first and the second at 25 deg. C., the second from 50 deg. to 150 deg. C. From the results of AGRON it is possible to predict the residual solids before complete volatilization as UF 6 . The IR spectra of ClO 2 F adsorbed on UF 4 and UF x at 60 deg. C have been compared with those of gaseous ClO 2 F and UF 6 adsorbed on UF 4 . (authors) [fr

  15. Behaviour of atomic oxygen in a pulsed dielectric barrier discharge measured by laser-induced fluorescence

    International Nuclear Information System (INIS)

    Ono, Ryo; Yamashita, Youta; Takezawa, Kei; Oda, Tetsuji

    2005-01-01

    Atomic oxygen is measured in a pulsed dielectric barrier discharge (DBD) using two-photon absorption laser-induced fluorescence (TALIF). The ground-level atomic oxygen is excited to the 3p 3 P state by two-photon absorption at 226 nm. Negative (-40 kV) or positive (+30 kV) pulsed DBD occurs in an O 2 -N 2 mixture at atmospheric pressure. The pulse width of the DBD current is approximately 50 ns. The TALIF experiment shows that the decay rate of atomic oxygen increases linearly with O 2 concentration. This result proves that atomic oxygen decays mainly by the third-body reaction, O + O 2 + M → O 3 + M. The rate coefficient of the third-body reaction is estimated to be 2.2 x 10 -34 cm 6 s -1 in the negative DBD and 0.89 x 10 -34 cm 6 s -1 in the positive DBD. It is shown that the decay rate of atomic oxygen increases linearly with humidity. This can explain the well-known fact that ozone production in DBD is suppressed by increasing humidity

  16. Seasonal variations in VO2max, O2-cost, O2-deficit, and performance in elite cross-country skiers.

    Science.gov (United States)

    Losnegard, Thomas; Myklebust, Håvard; Spencer, Matt; Hallén, Jostein

    2013-07-01

    Long-term effects of training are important information for athletes, coaches, and scientists when associating changes in physiological indices with changes in performance. Therefore, this study monitored changes in aerobic and anaerobic capacities and performance in a group of elite cross-country skiers during a full sport season. Thirteen men (age, 23 ± 2 years; height, 182 ± 6 cm; body mass, 76 ± 8 kg; V2 roller ski skating VO2max, 79.3 ± 4.4 ml·kg·min or 6.0 ± 0.5 L·min) were tested during the early, middle, and late preparation phase: June (T1), August (T2), and October (T3); during the competition phase: January/February (T4); and after early precompetition phase: June (T5). O2-cost during submaximal efforts, V[Combining Dot Above]O2peak, accumulated oxygen deficit (ΣO2-deficit), and performance during a 1,000-m test were determined in the V2 ski skating technique on a roller ski treadmill. Subjects performed their training on an individual basis, and detailed training logs were categorized into different intensity zones and exercise modes. Total training volume was highest during the summer months (early preseason) and decreased toward and through the winter season, whereas the volume of high-intensity training increased (all p size; ES = 0.63-1.37, moderate to large, all p country skiers induced no significant changes in V[Combining Dot Above]O2peak but improved performance, O2-cost, and ΣO2-deficit.

  17. Thermochemical nonequilibrium analysis of O2+Ar based on state-resolved kinetics

    International Nuclear Information System (INIS)

    Kim, Jae Gang; Boyd, Iain D.

    2015-01-01

    Highlights: • Thermochemical nonequilibrium studies for three lowest lying electronic states of O 2 . • The complete sets of the rovibrational state-to-state transition rates of O 2 +Ar. • Rovibrational relaxations and coupled chemical reactions of O 2 . • Nonequilibrium reaction rates of O 2 derived from the quasi-steady state assumption. - Abstract: The thermochemical nonequilibrium of the three lowest lying electronic states of molecular oxygen, O 2 (X 3 Σ g - ,a 1 Δ g ,b 1 Σ g + ), through interactions with argon is studied in the present work. The multi-body potential energy surfaces of O 2 +Ar are evaluated from the semi-classical RKR potential of O 2 in each electronic state. The rovibrational states and energies of each electronic state are calculated by the quantum mechanical method based on the present inter-nuclear potential of O 2 . Then, the complete sets of the rovibrational state-to-state transition rate coefficients of O 2 +Ar are calculated by the quasi-classical trajectory method including the quasi-bound states. The system of master equations constructed by the present state-to-state transition rate coefficients are solved to analyze the thermochemical nonequilibrium of O 2 +Ar in various heat bath conditions. From these studies, it is concluded that the vibrational relaxation and coupled chemical reactions of each electronic state needs to be treated as a separate nonequilibrium process, and rotational nonequilibrium needs to be considered at translational temperatures above 10,000 K

  18. Hazards of TiO2 and amorphous SiO2 nanoparticles

    NARCIS (Netherlands)

    Reijnders, L.; Kahn, H.A.; Arif, I.A.

    2012-01-01

    TiO2 and amorphous SiO2 nanoparticles have been described as ‘safe’, ‘non-toxic’ and ‘environment friendly’ in scientific literature. However, though toxicity data are far from complete, there is evidence that these nanoparticles are hazardous. TiO2 nanoparticles have been found hazardous to humans

  19. Production of O2(1Δ) in flowing plasmas using spiker-sustainer excitation

    International Nuclear Information System (INIS)

    Babaeva, Natalia Y.; Arakoni, Ramesh A.; Kushner, Mark J.

    2006-01-01

    In chemical oxygen iodine lasers (COILs), oscillation at 1.315 μm in atomic iodine ( 2 P 1/2 → 2 P 3/2 ) is produced by collisional excitation transfer of O 2 ( 1 Δ) to I 2 and I. Plasma production of O 2 ( 1 Δ) in electrical COILs (eCOILs) eliminates liquid phase generators. For the flowing plasmas used for eCOILs (He/O 2 , a few to tens of torr), self-sustaining electron temperatures, T e , are 2-3 eV whereas excitation of O 2 ( 1 Δ) optimizes with T e =1-1.5 eV. One method to increase O 2 ( 1 Δ) production is by lowering the average value of T e using spiker-sustainer (SS) excitation where a high power pulse (spiker) is followed by a lower power period (sustainer). Excess ionization produced by the spiker enables the sustainer to operate with a lower T e . Previous investigations suggested that SS techniques can significantly raise yields of O 2 ( 1 Δ). In this paper, we report on the results from a two-dimensional computational investigation of radio frequency (rf) excited flowing He/O 2 plasmas with emphasis on SS excitation. We found that the efficiency of SS methods generally increase with increasing frequency by producing a higher electron density, lower T e , and, as a consequence, a more efficient production of O 2 ( 1 Δ)

  20. Structural and physical properties of transparent conducting, amorphous Zn-doped SnO2 films

    Science.gov (United States)

    Zhu, Q.; Ma, Q.; Buchholz, D. B.; Chang, R. P. H.; Bedzyk, M. J.; Mason, T. O.

    2014-01-01

    The structural and physical properties of conducting amorphous Zn-doped SnO2 (a-ZTO) films, prepared by pulsed laser deposition, were investigated as functions of oxygen deposition pressure (pO2), composition, and thermal annealing. X-ray scattering and X-ray absorption spectroscopy measurements reveal that at higher pO2, the a-ZTO films are highly transparent and have a structural framework similar to that found in crystalline (c-), rutile SnO2 in which the Sn4+ ion is octahedrally coordinated by 6 O2- ions. The Sn4+ ion in these films however has a coordination number (CN) smaller by 2%-3% than that in c-SnO2, indicating the presence of oxygen vacancies, which are the likely source of charge carriers. At lower pO2, the a-ZTO films show a brownish tint and contain some 4-fold coordinated Sn2+ ions. Under no circumstances is the CN around the Zn2+ ion larger than 4, and the Zn-O bond is shorter than the Sn-O bond by 0.07 Å. The addition of Zn has no impact on the electroneutrality but improves significantly the thermal stability of the films. Structural changes due to pO2, composition, and thermal annealing account well for the changes in the physical properties of a-ZTO films.

  1. Target swapping in PLD: An efficient approach for CdS/SiO2 and CdS:Ag(1%)/SiO2 nanocomposite thin films with enhanced luminescent properties

    International Nuclear Information System (INIS)

    Saxena, Nupur; Kumar, Pragati; Gupta, Vinay

    2017-01-01

    A novel synthesis method for luminescent and by-products (like CdO) free CdS/SiO 2 and CdS:Ag(1%)/SiO 2 (i.e. 1%Ag doped CdS/SiO 2 ) nanocomposite thin films at room temperature by pulsed laser deposition is reported. Targets of CdS, CdS:Ag(1%) and SiO 2 are used to deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposite thin films by swapping them at a frequency ratio of 2:8 laser pulses/sec. X-ray photoelectron spectroscopy analysis ensures the ratio of CdS to SiO 2 in nanocomposite as 21:79 which is nearly same as the ratio of incident pulses/sec (i.e. 2:8) on the two targets. Transmission electron micrographs visualize the formation of CdS/ CdS:Ag(1%) nanocrystals in nanocomposite systems after annealing at 500 °C. Highly intense and broad red emission is achieved from CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposites. The efficiencies of emission from pristine CdS:SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposites are found to be enhanced by approximately two times as compared to sole nanocrystalline CdS and CdS:Ag(1%) thin films respectively and further enhanced upto 7 times on annealing the nanocomposite systems at 500 °C. - Graphical abstract: A modified synthesis method for luminescent and by-products (like CdO) free undoped &1% Ag doped CdS/SiO 2 (deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 ) nanocomposite thin films at room temperature by pulsed laser deposition is reported. Targets of CdS or CdS:Ag(1%) and SiO 2 are used to deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposite thin films by swapping them at a frequency of 2:8 pulses/sec. X-ray photoelectron spectroscopy analysis ensures the ratio of CdS to SiO 2 in nanocomposite as 21:79 which is nearly same as the ratio of incident pulses/sec (2:8) on the two targets. Transmission electron micrographs visualize the formation of CdS nanocrystals in nanocomposite systems after annealing at 500 °C. Intense and broad red emission is achieved from deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposites. The efficiency of

  2. Interface engineered HfO2-based 3D vertical ReRAM

    International Nuclear Information System (INIS)

    Hudec, Boris; Wang, I-Ting; Lai, Wei-Li; Chang, Che-Chia; Hou, Tuo-Hung; Jančovič, Peter; Fröhlich, Karol; Mičušík, Matej; Omastová, Mária

    2016-01-01

    We demonstrate a double-layer 3D vertical resistive random access memory (ReRAM) stack implementing a Pt/HfO 2 /TiN memory cell. The HfO 2 switching layer is grown by atomic layer deposition on the sidewall of a SiO 2 /TiN/SiO 2 /TiN/SiO 2 multilayer pillar. A steep vertical profile was achieved using CMOS-compatible TiN dry etching. We employ in situ TiN bottom interface engineering by ozone, which results in (a) significant forming voltage reduction which allows for forming-free operation in AC pulsed mode, and (b) non-linearity tuning of low resistance state by current compliance during Set operation. The vertical ReRAM shows excellent read and write disturb immunity between vertically stacked cells, retention over 10 4 s and excellent switching stability at 400 K. Endurance of 10 7 write cycles was achieved using 100 ns wide AC pulses while fast switching speed using pulses of only 10 ns width is also demonstrated. The active switching region was evaluated to be located closer to the bottom interface which allows for the observed high endurance. (paper)

  3. Measurements and kinetic modeling of atomic species in fuel-oxidizer mixtures excited by a repetitive nanosecond pulse discharge

    Science.gov (United States)

    Winters, C.; Eckert, Z.; Yin, Z.; Frederickson, K.; Adamovich, I. V.

    2018-01-01

    This work presents the results of number density measurements of metastable Ar atoms and ground state H atoms in diluted mixtures of H2 and O2 with Ar, as well as ground state O atoms in diluted H2-O2-Ar, CH4-O2-Ar, C3H8-O2-Ar, and C2H4-O2-Ar mixtures excited by a repetitive nanosecond pulse discharge. The measurements have been made in a nanosecond pulse, double dielectric barrier discharge plasma sustained in a flow reactor between two plane electrodes encapsulated within dielectric material, at an initial temperature of 500 K and pressures ranging from 300 Torr to 700 Torr. Metastable Ar atom number density distribution in the afterglow is measured by tunable diode laser absorption spectroscopy, and used to characterize plasma uniformity. Temperature rise in the reacting flow is measured by Rayleigh scattering. H atom and O atom number densities are measured by two-photon absorption laser induced fluorescence. The results are compared with kinetic model predictions, showing good agreement, with the exception of extremely lean mixtures. O atoms and H atoms in the plasma are produced mainly during quenching of electronically excited Ar atoms generated by electron impact. In H2-Ar and O2-Ar mixtures, the atoms decay by three-body recombination. In H2-O2-Ar, CH4-O2-Ar, and C3H8-O2-Ar mixtures, O atoms decay in a reaction with OH, generated during H atom reaction with HO2, with the latter produced by three-body H atom recombination with O2. The net process of O atom decay is O  +  H  →  OH, such that the decay rate is controlled by the amount of H atoms produced in the discharge. In extra lean mixtures of propane and ethylene with O2-Ar the model underpredicts the O atom decay rate. At these conditions, when fuel is completely oxidized by the end of the discharge burst, the net process of O atom decay, O  +  O  →  O2, becomes nearly independent of H atom number density. Lack of agreement with the data at these conditions is

  4. Propan-1-ol Oxidation Reaction on Au/TiO 2 Catalysts | Nuhu ...

    African Journals Online (AJOL)

    This was further investigated using Pulse Flow reactor, TPFRP, TPD, and XRD,. The adsorption of propan-1-ol over TiO2 (P25) indicated a full monolayer with much of it in a dissociated state, forming propoxy group on the cationic site and hydroxyl group at anions. The propoxy is relatively stable until about 250oC, at which ...

  5. Interaction of Al with O2 exposed Mo2BC

    International Nuclear Information System (INIS)

    Bolvardi, Hamid; Music, Denis; Schneider, Jochen M.

    2015-01-01

    Highlights: • Al adheres to many surfaces. • Solid–solid interactions challenging for real (oxidized) surfaces. • Dissociative O 2 adsorption on Mo 2 BC(0 4 0). • Al nonamer is disrupted on oxidized Mo 2 BC(0 4 0). • Adhesion of a residual Al on the native oxide. - Abstract: A Mo 2 BC(0 4 0) surface was exposed to O 2 . The gas interaction was investigated using ab initio molecular dynamics and X-ray photoelectron spectroscopy (XPS) of air exposed surfaces. The calculations suggest that the most dominating physical mechanism is dissociative O 2 adsorption whereby Mo−O, O−Mo−O and Mo 2 −C−O bond formation is observed. To validate these results, Mo 2 BC thin films were synthesized utilizing high power pulsed magnetron sputtering and air exposed surfaces were probed by XPS. MoO 2 and MoO 3 bond formation is observed and is consistent with here obtained ab initio data. Additionally, the interfacial interactions of O 2 exposed Mo 2 BC(0 4 0) surface with an Al nonamer is studied with ab initio molecular dynamics to describe on the atomic scale the interaction between this surface and Al to mimic the interface present during cold forming processes of Al based alloys. The Al nonamer was disrupted and Al forms chemical bonds with oxygen contained in the O 2 exposed Mo 2 BC(0 4 0) surface. Based on the comparison of here calculated adsorption energy with literature data, Al−Al bonds are shown to be significantly weaker than the Al−O bonds formed across the interface. Hence, Al−Al bond rupture is expected for a mechanically loaded interface. Therefore the adhesion of a residual Al on the native oxide layer is predicted. This is consistent with experimental observations. The data presented here may also be relevant for other oxygen containing surfaces in a contact with Al or Al based alloys for example during forming operations

  6. Properties of phases in HfO2-TiO2 system

    International Nuclear Information System (INIS)

    Red'ko, V.P.; Terekhovskij, P.B.; Majster, I.M.; Shevchenko, A.V.; Lopato, L.M.; Dvernyakova, A.A.

    1990-01-01

    A study was made on axial and linear coefficients of thermal expansion (CTE) of HfO 2 -TiO 2 system samples in concentration range of 25-50 mol% TiO 2 . Samples, containing 35 and 37 mol% TiO 2 , are characterized by the lowest values of linear CTE. Dispersion of the basic substances doesn't affect CTE value. Correlation with axial and linear CTE of samples in ZrO 2 -TiO 2 system was conducted. Presence of anisotropy of change of lattice parameters was supported for samples, containing 37.5 and 40 mol% TiO 2 . Polymorphous transformations for hafnium titanate were not revealed

  7. Heat capacity of ThO2

    International Nuclear Information System (INIS)

    Peng Shian

    1996-01-01

    The heat capacity C p of ThO 2 can be calculated as the phonon part of C p for other actinide dioxides used as fuel in nuclear reactors. Precise determination of the phonon part of C p of actinide dioxides is helpful to find out the contributions of other factors to C p . In this paper we have, through studying the heat capacity of ThO 2 , developed a general method applicable to the study of C p of other solids. In the developed method the three type -- different experimental measurements made on a solid-heat capacity, thermal expansion and Debye Waller factor -- can be brought together for comparison. The application of this method to the study of C p of ThO 2 has enabled us to propose a better description of C p of ThO 2 than the generally accepted expression

  8. Novel Ag@TiO2 nanocomposite synthesized by electrochemically active biofilm for nonenzymatic hydrogen peroxide sensor

    International Nuclear Information System (INIS)

    Khan, Mohammad Mansoob; Ansari, Sajid Ali; Lee, Jintae; Cho, Moo Hwan

    2013-01-01

    A novel nonenzymatic sensor for H 2 O 2 was developed based on an Ag@TiO 2 nanocomposite synthesized using a simple and cost effective approach with an electrochemically active biofilm. The optical, structural, morphological and electrochemical properties of the as-prepared Ag@TiO 2 nanocomposite were examined by UV–vis spectroscopy, X-ray diffraction, transmission electron microscopy and cyclic voltammetry (CV). The Ag@TiO 2 nanocomposite was fabricated on a glassy carbon electrode (GCE) and their electrochemical performance was analyzed by CV, differential pulse voltammetry and electrochemical impedance spectroscopy. The Ag@TiO 2 nanocomposite modified GCE (Ag@TiO 2 /GCE) displayed excellent performance towards H 2 O 2 sensing at − 0.73 V in the linear response range from 0.83 μM to 43.3 μM, within a detection limit and sensitivity of 0.83 μM and ∼ 65.2328 ± 0.01 μAμM −1 cm −2 , respectively. In addition, Ag@TiO 2 /GCE exhibited good operational reproducibility and long term stability. - Graphical abstract: Synthesis of Ag@TiO 2 nanocomposite by electrochemically active biofilm for H 2 O 2 sensing. - Highlights: • Electrochemically active biofilm (EAB) • EAB mediated synthesis of Ag@TiO 2 nanocomposite • Ag@TiO 2 nanocomposite modified glassy carbon electrode • Ag@TiO 2 /GCE for H 2 O 2 sensing • Nonenzymatic sensor for H 2 O 2

  9. The ceramic SiO2 and SiO2-TiO2 coatings on biomedical Ti6Al4VELI titanium alloy

    International Nuclear Information System (INIS)

    Surowska, B.; Walczak, M.; Bienias, J.

    2004-01-01

    The paper presents the study of intermediate SiO 2 and SiO 2 -TiO 2 sol-gel coatings and dental porcelain coatings on Ti6Al4VELI titanium alloy. Surface microstructures and wear behaviour by pin-on-disc method of the ceramic coatings were investigated. The analysis revealed: (1) a compact, homogeneous SiO 2 and SiO 2 -TiO 2 coating and (2) that intermediate coatings may provide a durable joint between metal and porcelain, and (3) that dental porcelain on SiO 2 and TiO 2 coatings shows high wear resistance. (author)

  10. Carbon dioxide and water adsorption on highly epitaxial Delafossite CuFeO2 thin film

    Science.gov (United States)

    Rojas, S.; Joshi, T.; Borisov, P.; Sarabia, M.; Lederman, D.; Cabrera, A. L.

    2015-03-01

    Thermal programmed desorption (TPD) of CO2 and H2O from a 200 nm thick CuFeO2 Delafossite surface was performed in a standard UHV chamber, The CuFeO2 thin film grown using Pulsed Laser Deposition (PLD) over an Al2O3 (0001) substrate with controlled O2 atmosphere resulted with highly epitaxial crystal structure. The adsorption/desorption of CO2 and H2O process was also monitored with X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Our results revealed that carbon dioxide interacts with CuFeO2 forming Fe carbonates compounds on its surface. Hydroxides were also formed on the surface due to water presence. Using TPD data, Arrhenius plots for CO2 and water desorption were done and activation energy for desorption was obtained. Funds FONDECyT 1130372; Thanks to P. Ferrari.

  11. O2(a1Δ) vibrational kinetics in oxygen-iodine laser

    Science.gov (United States)

    Torbin, A. P.; Pershin, A. A.; Heaven, M. C.; Azyazov, V. N.; Mebel, A. M.

    2018-04-01

    Kinetics of vibrationally-excited singlet oxygen O2(a1Δ,ν) in gas mixture O3/N2/CO2 was studied using a pulse laser technique. Molecules O2(a1Δ,ν) were produced by laser photolysis of ozone at 266 nm. The O3 molecules number density was followed using time-resolved absorption spectroscopy. It was found that an upper bound for the rate constant of chemical reaction O2(a1Δ,ν)+ O3 is about 10-15 cm3/s. The rate constants of O2(a1Δ,ν= 1, 2 and 3) quenching by CO2 are presented.

  12. PECVD SiO2 dielectric for niobium Josephson IC process

    International Nuclear Information System (INIS)

    Lee, S.Y.; Nandakumar, V.; Murdock, B.; Hebert, D.

    1991-01-01

    PECVD SiO 2 dielectric has been evaluated as an insulator for a Nb-based, all-refractory Josephson integrated circuit process. First, the properties of PECVD SiO 2 films were measured and compared with those of evaporated SiO films. Second, the PECVD SiO 2 dielectric film was used in our Nb-based Josephson integrated circuit process. The main problem was found to be the deterioration of the critical temperature of the superconducting niobium adjacent to the SiO 2 . The cause and a solution of the problem were investigated. Finally, a Josephson integrated sampler circuit was fabricated and tested. This paper shows acceptable junction I-V characteristics and a measured time resolution of a 4.9 ps pulse in liquid helium

  13. Thermal and Mechanical Properties of UO2 and PuO2

    International Nuclear Information System (INIS)

    Kato, M.; Matsumoto, T.

    2015-01-01

    It is important to evaluate basic properties of UO 2 and PuO 2 as fundamental aspects of MA-bearing MOX fuel development. In this work, mechanical properties of UO 2 and PuO 2 were investigated by an ultrasound pulse-echo method. Longitudinal and transversal wave velocities were measured in UO 2 and PuO 2 pellets, and Young's modulus and shear modulus were evaluated, which were 219 MPa and 89 MPa for PuO 2 , and 249 MPa and 95 MPa for UO 2 , respectively. Poisson's ratio was 0.32 in both materials. The relationship between mechanical and thermal properties was described by using thermal expansion data which had been reported previously, and the heat capacity and thermal conductivity were analysed. (authors)

  14. Comparisons between TiO2- and SiO2-flux assisted TIG welding processes.

    Science.gov (United States)

    Tseng, Kuang-Hung; Chen, Kuan-Lung

    2012-08-01

    This study investigates the effects of flux compounds on the weld shape, ferrite content, and hardness profile in the tungsten inert gas (TIG) welding of 6 mm-thick austenitic 316 L stainless steel plates, using TiO2 and SiO2 powders as the activated fluxes. The metallurgical characterizations of weld metal produced with the oxide powders were evaluated using ferritoscope, optical microscopy, and Vickers microhardness test. Under the same welding parameters, the penetration capability of TIG welding with TiO2 and SiO2 fluxes was approximately 240% and 292%, respectively. A plasma column made with SiO2 flux exhibited greater constriction than that made with TiO2 flux. In addition, an anode root made with SiO2 flux exhibited more condensation than that made with TiO2 flux. Results indicate that energy density of SiO2-flux assisted TIG welding is higher than that of TiO2-flux assisted TIG welding.

  15. Relationship of O2 Photodesorption in Photooxidation of Acetone on TiO2

    International Nuclear Information System (INIS)

    Henderson, Michael A.

    2008-01-01

    Organic photooxidation on TiO2 invariably involves the coexistence of organic species with oxygen on the surface at the same time. In the case of acetone and oxygen, both species exhibit their own interesting photochemistry on TiO2, but interdependences between the two are not understood. In this study, a rutile TiO2(110) surface possessing 7% surface oxygen vacancy sites is used as a model surface to probe the relationship between O2 photodesorption and acetone photodecomposition. Temperature programmed desorption (TPD) and photon stimulated desorption (PSD) measurements indicate that coadsorbed oxygen is essential to acetone photodecomposition on this surface, however the form of oxygen (molecular and dissociative) is not known. The first steps in acetone photodecomposition on TiO2(110) involve thermal activation with oxygen to form an acetone diolate ((CH3)2COO) species followed by photochemical decomposition to adsorbed acetate (CH3COO) and an ejected CH3 radical that is detected in PSD. Depending on the surface conditions, O2 PSD is also observed during the latter process. However, the time scales for the two PSD events (CH3 and O2) are quite different, with the former occurring at ∼10 times faster than the latter. By varying the preheating conditions or performing pre-irradiation on an O2 exposed surface, it becomes clear that the two PSD events are uncorrelated. That is, the O2 species responsible for O2 PSD is not a significant participant in the photochemistry of acetone on TiO2(110) and likely originates from a minority form of O2 on the surface. The CH3 and O2 PSD events do not appear to be in competition with each other suggesting either that ample charge carriers exist under the experimental conditions employed or that different charge carriers or excitation mechanisms are involved

  16. Comparative study of neurologic effects of nano-TiO2 versus SiO2 after direct intracerebral exposure in mice

    International Nuclear Information System (INIS)

    Balvay, A; Bencsik, A; Thieriet, N; Lakhdar, L

    2013-01-01

    Titanium and silicon dioxide nanoparticles (TiO 2 and SiO 2 NPs) are now in daily use in many commercial products of which food, sunscreens, toothpastes or cosmetics. However, their effects on human body, especially on the central nervous system, are still unclear. The aim of this study was to determine whether direct exposition of the brain to TiO 2 and SiO 2 NPs results in alternations in nervous system function. C57Bl6 mice were exposed to 5 and 10 μg doses of TiO 2 and SiO 2 NPs through intracerebroventricular administration using a stereotaxic approach. Then the neurologic effects were investigated using motor performance parameters, measured on a rotarod at 20 rpm or at an accelerating rod (from 4 to 40 rpm). Before and after injection, motor activity is registered individually for each mouse exposed, once a week, for 8 weeks. Besides, a group of 3 mice is culled at 1, 2, 3, 4 and 8 weeks after exposure in order to study the time dependant effect on the histopathology of the brain (gliosis, inflammatory process...). Both rotarod tests (accelerating and at 20 rpm) showed that TiO 2 and SiO 2 NPs exposure could significantly impair the motor performances, even several weeks after initial acute exposure. The first examination of the brain histopathology revealed microglial activation. As it appeared to grow throughout the brain in a time dependant manner this suggests the induction of a long lasting neuroinflammation. These primary findings indicated that exposure to TiO 2 and SiO 2 NPs could possibly impair the locomotor ability and this deficit may be possibly attributed at least to an inflammatory process maintained till 8 weeks after exposure in the mouse brain. To fully investigate the neurotoxicological consequences of TiO 2 and SiO 2 NPs exposure, brain contents in these NPs will be also investigated as well as other alterations like neurotransmitter levels. These preliminary data already underline the necessity of more in vivo studies to better

  17. Comparative study of neurologic effects of nano-TiO2 versus SiO2 after direct intracerebral exposure in mice

    Science.gov (United States)

    Balvay, A.; Thieriet, N.; Lakhdar, L.; Bencsik, A.

    2013-04-01

    Titanium and silicon dioxide nanoparticles (TiO2 and SiO2 NPs) are now in daily use in many commercial products of which food, sunscreens, toothpastes or cosmetics. However, their effects on human body, especially on the central nervous system, are still unclear. The aim of this study was to determine whether direct exposition of the brain to TiO2 and SiO2 NPs results in alternations in nervous system function. C57Bl6 mice were exposed to 5 and 10 μg doses of TiO2 and SiO2 NPs through intracerebroventricular administration using a stereotaxic approach. Then the neurologic effects were investigated using motor performance parameters, measured on a rotarod at 20 rpm or at an accelerating rod (from 4 to 40 rpm). Before and after injection, motor activity is registered individually for each mouse exposed, once a week, for 8 weeks. Besides, a group of 3 mice is culled at 1, 2, 3, 4 and 8 weeks after exposure in order to study the time dependant effect on the histopathology of the brain (gliosis, inflammatory process...). Both rotarod tests (accelerating and at 20 rpm) showed that TiO2 and SiO2 NPs exposure could significantly impair the motor performances, even several weeks after initial acute exposure. The first examination of the brain histopathology revealed microglial activation. As it appeared to grow throughout the brain in a time dependant manner this suggests the induction of a long lasting neuroinflammation. These primary findings indicated that exposure to TiO2 and SiO2 NPs could possibly impair the locomotor ability and this deficit may be possibly attributed at least to an inflammatory process maintained till 8 weeks after exposure in the mouse brain. To fully investigate the neurotoxicological consequences of TiO2 and SiO2 NPs exposure, brain contents in these NPs will be also investigated as well as other alterations like neurotransmitter levels. These preliminary data already underline the necessity of more in vivo studies to better characterize TiO2

  18. Effects of peripheral cold application on core body temperature and haemodynamic parameters in febrile patients.

    Science.gov (United States)

    Asgar Pour, Hossein; Yavuz, Meryem

    2014-04-01

    This study designed to assess the effects of peripheral cold application (PCA) on core body temperature and haemodynamic parameters in febrile patients. This study was an experimental, repeated-measures performed in the neurosurgical intensive-care unit. The research sample included all patients with fever in postoperative period. PCA was performed for 20 min. During fever, systolic blood pressure, mean arterial blood pressure and arterial oxygen saturation (O2 Sat) decreased by 5.07 ± 7.89 mm Hg, 0.191 ± 6.00 mm Hg and 0.742% ± 0.97%, respectively, whereas the pulse rate and diastolic blood pressure increased by 8.528 ± 4.42 beats/ min and 1.842 ± 6.9 mmHg, respectively. Immediately after PCA, core body temperature and pulse rate decreased by 0.3°C, 3.3 beats/min, respectively, whereas systolic, diastolic, mean arterial blood pressure and O2 Sat increased by, 1.40 mm Hg, 1.87 mm Hg, 0.98 mmHg and 0.27%, respectively. Thirty minutes after the end of PCA, core body temperature, diastolic, mean arterial blood pressure and pulse rate decreased by 0.57°C, 0.34 mm Hg, 0.60 mm Hg and 4.5 beats/min, respectively, whereas systolic blood pressure and O2 Sat increased by 0.98 mm Hg and 0.04%, respectively. The present results showed that PCA increases systolic, diastolic, mean arterial blood pressure and O2 Sat, and decreases core body temperature and pulse rate. © 2013 Wiley Publishing Asia Pty Ltd.

  19. Enhanced properties of nanostructured TiO2-graphene composites by rapid sintering

    Science.gov (United States)

    Shon, In-Jin; Yoon, Jin-Kook; Hong, Kyung-Tae

    2018-01-01

    Despite of many attractive properties of TiO2, the drawback of TiO2 ceramic is low fracture toughness for widely industrial application. The method to improve the fracture toughness and hardness has been reported by addition of reinforcing phase to fabricate a nanostructured composite. In this regard, graphene has been evaluated as an ideal second phase in ceramics. Nearly full density of nanostructured TiO2-graphene composite was achieved within one min using pulsed current activated sintering. The effect of graphene on microstructure, fracture toughness and hardness of TiO2-graphene composite was evaluated using Vickers hardness tester and field emission scanning electron microscopy. The grain size of TiO2 in the TiO2-x vol% (x = 0, 1, 3, and 5) graphene composite was greatly reduced with increase in addition of graphene. Both hardness and fracture toughness of TiO2-graphene composites simultaneously increased in the addition of graphene.

  20. Fabrication, structure, and enhanced photocatalytic properties of hierarchical CeO2 nanostructures/TiO2 nanofibers heterostructures

    International Nuclear Information System (INIS)

    Cao, Tieping; Li, Yuejun; Wang, Changhua; Wei, Liming; Shao, Changlu; Liu, Yichun

    2010-01-01

    Combining the versatility of electrospinning technique and hydrothermal growth of nanostructures enabled the fabrication of hierarchical CeO 2 /TiO 2 nanofibrous mat. The as-prepared hierarchical heterostructure consisted of CeO 2 nanostructures growing on the primary TiO 2 nanofibers. Interestingly, not only were secondary CeO 2 nanostructures successfully grown on TiO 2 nanofibers substrates, but also the CeO 2 nanostructures were uniformly distributed without aggregation on TiO 2 nanofibers. By selecting different alkaline source, CeO 2 /TiO 2 heterostructures with CeO 2 nanowalls or nanoparticles were facilely fabricated. The photocatalytic studies suggested that the CeO 2 /TiO 2 heterostructures showed enhanced photocatalytic efficiency of photodegradation of dye pollutants compared with bare TiO 2 nanofibers under UV light irradiation.

  1. Influence of CeO2 on structural properties of glasses by using ultrasonic technique: comparison between the local sand and SiO2.

    Science.gov (United States)

    Laopaiboon, Raewat; Bootjomchai, Cherdsak

    2013-04-01

    Comparison between the local sand and SiO2 with different compositions of CeO2 on the structural properties of glasses was carried out by using ultrasonic technique. The ultrasonic velocities were measured by the pulse echo technique with a frequency of 4 MHz and at room temperature. From these obtained velocities and densities, various elastic moduli, micro-hardness and Poisson's ratio were calculated. The interesting point of the bulk modulus (SiO2 glass system) decreases at x = 1.25 mol.% initially before it turns to increase between x = 3.75 and x = 5.00 mol.%. While the bulk modulus of the local sand glass system is near constant. FTIR spectra were used to study the structural properties of the prepared glass system. The results supported our discussion of the formation of non-bridging oxygens (NBO) and bridging oxygens (BO). Copyright © 2013 Elsevier B.V. All rights reserved.

  2. The Effect of Titanium Dioxide (TiO2) Nanoparticles on Hydroxyapatite (HA)/TiO2 Composite Coating Fabricated by Electrophoretic Deposition (EPD)

    Science.gov (United States)

    Amirnejad, M.; Afshar, A.; Salehi, S.

    2018-05-01

    Composite coatings of Hydroxyapatite (HA) with ceramics, polymers and metals are used to modify the surface structure of implants. In this research, HA/TiO2 composite coating was fabricated by electrophoretic deposition (EPD) on 316 stainless steel substrate. HA/TiO2 composite coatings with 5, 10 and 20 wt.% of TiO2, deposited at 40 V and 90 s as an optimum condition. The samples coated at this condition led to an adherent, continuous and crack-free coating. The influence of TiO2 content was studied by performing different characterization methods such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), corrosion resistance in simulated body fluid (SBF), coating's dissolution rate in physiological solution and bond strength to the substrate. The results showed that the higher amount of TiO2 in the composite coating led to increase in bond strength of coating to stainless steel substrate from 3 MPa for HA coating to 5.5 MPa for HA-20 wt.% TiO2 composite coating. In addition, it caused to reduction of corrosion current density of samples in the SBF solution from 18.92 μA/cm2 for HA coating to 6.35 μA/cm2 for HA-20 wt.% TiO2 composite coating.

  3. The Effect of Titanium Dioxide (TiO2) Nanoparticles on Hydroxyapatite (HA)/TiO2 Composite Coating Fabricated by Electrophoretic Deposition (EPD)

    Science.gov (United States)

    Amirnejad, M.; Afshar, A.; Salehi, S.

    2018-04-01

    Composite coatings of Hydroxyapatite (HA) with ceramics, polymers and metals are used to modify the surface structure of implants. In this research, HA/TiO2 composite coating was fabricated by electrophoretic deposition (EPD) on 316 stainless steel substrate. HA/TiO2 composite coatings with 5, 10 and 20 wt.% of TiO2, deposited at 40 V and 90 s as an optimum condition. The samples coated at this condition led to an adherent, continuous and crack-free coating. The influence of TiO2 content was studied by performing different characterization methods such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), corrosion resistance in simulated body fluid (SBF), coating's dissolution rate in physiological solution and bond strength to the substrate. The results showed that the higher amount of TiO2 in the composite coating led to increase in bond strength of coating to stainless steel substrate from 3 MPa for HA coating to 5.5 MPa for HA-20 wt.% TiO2 composite coating. In addition, it caused to reduction of corrosion current density of samples in the SBF solution from 18.92 μA/cm2 for HA coating to 6.35 μA/cm2 for HA-20 wt.% TiO2 composite coating.

  4. Pulse Generator

    Science.gov (United States)

    Greer, Lawrence (Inventor)

    2017-01-01

    An apparatus and a computer-implemented method for generating pulses synchronized to a rising edge of a tachometer signal from rotating machinery are disclosed. For example, in one embodiment, a pulse state machine may be configured to generate a plurality of pulses, and a period state machine may be configured to determine a period for each of the plurality of pulses.

  5. Enhancement of photocatalytic properties of TiO2 nanoparticles doped with CeO2 and supported on SiO2 for phenol degradation

    International Nuclear Information System (INIS)

    Hao, Chunjing; Li, Jing; Zhang, Zailei; Ji, Yongjun; Zhan, Hanhui; Xiao, Fangxing; Wang, Dan; Liu, Bin; Su, Fabing

    2015-01-01

    Highlights: • CeO 2 -TiO 2 /SiO 2 composites were prepared via a facile co-precipitation method. • Introduction of SiO 2 support increases the dispersion of CeO 2 -TiO 2 . • CeO 2 -TiO 2 /SiO 2 exhibits an enhanced photocatalytic efficiency for phenol degradation. • Ce 3+ /Ce 4+ pair coexisting in CeO 2 improves electron–hole pairs separation efficiency. - Abstract: A series of CeO 2 -TiO 2 and CeO 2 -TiO 2 /SiO 2 composites were prepared with TiCl 4 and Ce (NO 3 ) 3 ·6H 2 O as precursors via a facile co-precipitation method. The obtained samples were characterized by various techniques such as X-ray diffraction (XRD), nitrogen adsorption (N 2 -BET), Fourier transformation infrared spectrum (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–Vis spectroscopy measurements. The results indicated that TiO 2 doped with CeO 2 and supported on SiO 2 could reduce the crystallite size, inhibit the phase transformation, enhance the thermal stability, and effectively extend the spectral response from UV to visible range. When applied to the phenol photodegradation on a homemade batch reactor with an external cooling jacket, the CeO 2 -TiO 2 /SiO 2 catalysts exhibited significantly enhanced photodegradation efficiency in comparison with commercial Degussa P25 and CeO 2 -TiO 2 . The unique catalytic properties of CeO 2 -TiO 2 /SiO 2 were ascribed to improved electron–hole pairs separation efficiency and formation of more reactive oxygen species owing to the presence of Ce 3+ /Ce 4+ , as well as high dispersion of active component of CeO 2 -TiO 2 as a result of the introduction of SiO 2 support. Furthermore, the catalysts can be easily recovered from the reaction solution by centrifugation and reused for four cycles without significant loss of activity

  6. Pulse oximetry: fundamentals and technology update

    Directory of Open Access Journals (Sweden)

    Nitzan M

    2014-07-01

    Full Text Available Meir Nitzan,1 Ayal Romem,2 Robert Koppel31Department of Physics/Electro-Optics, Jerusalem College of Technology, Jerusalem, Israel; 2Pulmonary Institute, Shaare Zedek Medical Center, Jerusalem, Israel; 3Neonatal/Perinatal Medicine, Cohen Children's Medical Center of New York/North Shore-LIJ Health System, New Hyde Park, NY, United StatesAbstract: Oxygen saturation in the arterial blood (SaO2 provides information on the adequacy of respiratory function. SaO2 can be assessed noninvasively by pulse oximetry, which is based on photoplethysmographic pulses in two wavelengths, generally in the red and infrared regions. The calibration of the measured photoplethysmographic signals is performed empirically for each type of commercial pulse-oximeter sensor, utilizing in vitro measurement of SaO2 in extracted arterial blood by means of co-oximetry. Due to the discrepancy between the measurement of SaO2 by pulse oximetry and the invasive technique, the former is denoted as SpO2. Manufacturers of pulse oximeters generally claim an accuracy of 2%, evaluated by the standard deviation (SD of the differences between SpO2 and SaO2, measured simultaneously in healthy subjects. However, an SD of 2% reflects an expected error of 4% (two SDs or more in 5% of the examinations, which is in accordance with an error of 3%–4%, reported in clinical studies. This level of accuracy is sufficient for the detection of a significant decline in respiratory function in patients, and pulse oximetry has been accepted as a reliable technique for that purpose. The accuracy of SpO2 measurement is insufficient in several situations, such as critically ill patients receiving supplemental oxygen, and can be hazardous if it leads to elevated values of oxygen partial pressure in blood. In particular, preterm newborns are vulnerable to retinopathy of prematurity induced by high oxygen concentration in the blood. The low accuracy of SpO2 measurement in critically ill patients and newborns

  7. Characterization of amorphous multilayered ZnO-SnO2 heterostructure thin films and their field effect electronic properties

    International Nuclear Information System (INIS)

    Lee, Su-Jae; Hwang, Chi-Sun; Pi, Jae-Eun; Yang, Jong-Heon; Oh, Himchan; Cho, Sung Haeng; Cho, Kyoung-Ik; Chu, Hye Yong

    2014-01-01

    Multilayered ZnO-SnO 2 heterostructure thin films were produced using pulsed laser ablation of pie-shaped ZnO-SnO 2 oxides target, and their structural and field effect electronic transport properties were investigated as a function of the thickness of the ZnO and SnO 2 layers. The films have an amorphous multilayered heterostructure composed of the periodic stacking of the ZnO and SnO 2 layers. The field effect electronic properties of amorphous multilayered ZnO-SnO 2 heterostructure thin film transistors (TFTs) are highly dependent on the thickness of the ZnO and SnO 2 layers. The highest electron mobility of 37 cm 2 /V s, a low subthreshold swing of a 0.19 V/decade, a threshold voltage of 0.13 V, and a high drain current on-to-off ratio of ∼10 10 obtained for the amorphous multilayered ZnO(1.5 nm)-SnO 2 (1.5 nm) heterostructure TFTs. These results are presumed to be due to the unique electronic structure of an amorphous multilayered ZnO-SnO 2 heterostructure film consisting of ZnO, SnO 2 , and ZnO-SnO 2 interface layers

  8. Electro-codeposition of Ni-SiO2 nanocomposite coatings from deep eutectic solvent with improved corrosion resistance

    Science.gov (United States)

    Li, Ruiqian; Hou, Yuanyuan; Liang, Jun

    2016-03-01

    Electro-codeposition of nano-sized SiO2 particles into the metal matrix in aqueous solution is generally difficult. In this paper, the nano-sized SiO2 particles were successfully codeposited in the Ni matrix from a choline chloride (ChCl)/ethylene glycol (EG) based deep eutectic solvent (DES) by pulse electro-codeposition. The effects of nano-sized SiO2 particles on electrochemical behaviour of Ni(II) were investigated. The microstructure, composition and corrosion resistance of pure Ni and Ni-SiO2 nanocomposite coatings were explored. Results showed that the SiO2 nanoparticles exhibited excellent dispersion stability in ChCl:2EG DES without any stabilizing additives and the presence of SiO2 nanoparticles have significant effects on the nucleation mechanism of Ni. The maximum content of SiO2 nanoparticles in composite coatings can achieve 4.69 wt.%, which closes to the level of co-deposition micro-sized SiO2 particles from aqueous solution. The Ni-SiO2 nanocomposite coatings exhibit much better corrosion resistance than pure Ni coating, and the corrosion resistance performance increases with increasing SiO2 content in the composite coatings.

  9. Use of MnO2 and MnO2 SiO2 for sorbing of Sr-90 from liquid rad waste

    International Nuclear Information System (INIS)

    Subiarto; Las, Thamzil; Aan BH, Martin; Utomo, Cahyo Hari

    1998-01-01

    The synthesis of MnO 2 adsorbent and MnO 2 -SiO 2 composite has been done. MnO 2 synthesis is done by the reaction of KMnO 4 , Mn(NO 3 ) 2 .4H 2 O and Na 2 S 2 O 4 ( MnO 2 -A, MnO 2 -B, and MnO 2 -T ). MnO 2 . SiO 2 is made from KMnO 4 , Na 2 SiO 3 , and H 2 O 2 . The result obtained show the best Sr-90 sorption by MnO 2 -A with Kd = 2085.63 ml/g, by MnO 2 -L with Kd = 755.09 ml/g, and by MnO 2 - SiO 2 composite with Kd = 1466.51 ml/g. From this result, we can conclude that MnO 2 -SiO 2 can be expanded for Sr-90 sorption from liquid radioactive waste. (author)

  10. Instability of Hydrogenated TiO2

    Energy Technology Data Exchange (ETDEWEB)

    Nandasiri, Manjula I.; Shutthanandan, V.; Manandhar, Sandeep; Schwarz, Ashleigh M.; Oxenford, Lucas S.; Kennedy, John V.; Thevuthasan, Suntharampillai; Henderson, Michael A.

    2015-11-06

    Hydrogenated TiO2 (H-TiO2) is toted as a viable visible light photocatalyst. We report a systematic study on the thermal stability of H-implanted TiO2 using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Protons (40 keV) implanted at a ~2 atom % level within a ~120 nm wide profile of rutile TiO2(110) were situated ~300 nm below the surface. NRA revealed that this H-profile broadened preferentially toward the surface after annealing at 373 K, dissipated out of the crystal into vacuum at 473 K, and was absent within the beam sampling depth (~800 nm) at 523 K. Photoemission showed that the surface was reduced in concert with these changes. Similar anneals had no effect on pristine TiO2(110). The facile bulk diffusivity of H in rutile, as well as its activity toward interfacial reduction, significantly limits the utilization of H-TiO2 as a photocatalyst. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. The research was performed using the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

  11. Facile preparation of MnO2 nanorods and evaluation of their supercapacitive characteristics

    Science.gov (United States)

    Aghazadeh, Mustafa; Asadi, Maryam; Maragheh, Mohammad Ghannadi; Ganjali, Mohammad Reza; Norouzi, Parviz; Faridbod, Farnoush

    2016-02-01

    The first time pulsed base (OH-) electrogeneration to the cathodic electrodeposition of MnO2 in nitrate bath was applied and MnO2 nanorods were obtained. The deposition experiments were performed under a pulse current mode with typical on-times and off-times (ton = 10 ms and toff = 50 ms) and a peak current density of 2 mA cm-2 (Ia = 2 mA cm-2). The structural characterization with XRD and FTIR revealed that the prepared MnO2 is composed of both α and γ phases. Morphological evaluations through SEM and TEM revealed that the prepared MnO2 contains nanorods of relative uniform structures (with an average diameter of 50 nm). The electrochemical measurements through cyclic voltammetry and charge-discharge techniques revealed that the prepared MnO2 nanostructures reveal an excellent capacitive behavior with specific capacitance values of 242, 167 and 98 F g-1 under the applied current densities of 2, 5 and 10 A g-1, respectively. Also, excellent long-term cycling stabilities of 94.8%, 89.1%, and 76.5% were observed after 1000 charge-discharge cycles at the current densities of 2, 5 and 10 A g-1.

  12. MAPLE deposition and characterization of SnO2 colloidal nanoparticle thin films

    International Nuclear Information System (INIS)

    Caricato, A P; Martino, M; Romano, F; Tunno, T; Valerini, D; Epifani, M; Rella, R; Taurino, A

    2009-01-01

    In this paper we report on the deposition and characterization of tin oxide (SnO 2 ) nanoparticle thin films. The films were deposited by the matrix-assisted pulsed laser evaporation (MAPLE) technique. SnO 2 colloidal nanoparticles with a trioctylphosphine capping layer were diluted in toluene with a concentration of 0.2 wt% and frozen at liquid nitrogen temperature. The frozen target was irradiated with a KrF (248 nm, τ = 20 ns) excimer laser (6000 pulses at 10 Hz). The nanoparticles were deposited on silica (SiO 2 ) and (1 0 0) Si substrates and submitted to morphological (high resolution scanning electron microscopy (SEM)), structural Fourier transform infrared spectroscopy (FTIR) and optical (UV-Vis transmission) characterizations. SEM and FTIR analyses showed that trioctylphosphine was the main component in the as-deposited films. The trioctylphosphine was removed after an annealing in vacuum at 400 0 C, thus allowing to get uniform SnO 2 nanoparticle films in which the starting nanoparticle dimensions were preserved. The energy gap value, determined by optical characterizations, was 4.2 eV, higher than the bulk SnO 2 energy gap (3.6 eV), due to quantum confinement effects.

  13. Spectral and ion emission features of laser-produced Sn and SnO2 plasmas

    Science.gov (United States)

    Hui, Lan; Xin-Bing, Wang; Du-Luo, Zuo

    2016-03-01

    We have made a detailed comparison of the atomic and ionic debris, as well as the emission features of Sn and SnO2 plasmas under identical experimental conditions. Planar slabs of pure metal Sn and ceramic SnO2 are irradiated with 1.06 μm, 8 ns Nd:YAG laser pulses. Fast photography employing an intensified charge coupled device (ICCD), optical emission spectroscopy (OES), and optical time of flight emission spectroscopy are used as diagnostic tools. Our results show that the Sn plasma provides a higher extreme ultraviolet (EUV) conversion efficiency (CE) than the SnO2 plasma. However, the kinetic energies of Sn ions are relatively low compared with those of SnO2. OES studies show that the Sn plasma parameters (electron temperature and density) are lower compared to those of the SnO2 plasma. Furthermore, we also give the effects of the vacuum degree and the laser pulse energy on the plasma parameters. Project supported by the National Natural Science Foundation of China (Grant No. 11304235) and the Director Fund of WNLO, China.

  14. Structure and properties of PbO2-CeO2 anodes on stainless steel

    International Nuclear Information System (INIS)

    Song, Yuehai; Wei, Gang; Xiong, Rongchun

    2007-01-01

    The lack of ideal anodes with excellent activity and stability is one of the critical problems in electrochemical oxidation for organic wastewater treatment. It is reported in this paper that the PbO 2 -CeO 2 films electrodeposited on stainless steel were used as catalytic electrodes for treating antibiotic wastewater. The PbO 2 -CeO 2 films on stainless steel were proved to be high stability, good activity and relatively low cost. Because of these properties, the films are more attractive than any other electrocatalytic materials among conventional dimensionally stable anodes (DSA). Experimental results showed that the PbO 2 -CeO 2 electrode has a service life of 1100 h in 3 M H 2 SO 4 solution under a current density of 1 A cm -2 at 35 o C, compared with 300 h for PbO 2 under the same conditions. The X-ray diffraction (XRD) patterns and SEM images indicated that the PbO 2 -CeO 2 films on stainless steel have a dense structure and the preferred crystalline orientation on the substrate surface was changed. Color and chemical oxygen demand (COD) of antibiotics wastewater were studied by electrolysis by using these electrodes as anode and stainless steel as cathode. The results indicated that the anodes have excellent activity in antibiotic wastewater treatment. The PbO 2 -CeO 2 electrodes have high chemical stability which contributed by the superstable nature of the electrode, dense microstructure, good conductivity and the improvement of bonding with the stainless steel during electrodeposition

  15. Removal of pharmaceutically active compounds from synthetic and real aqueous mixtures and simultaneous disinfection by supported TiO2/UV-A, H2O2/UV-A, and TiO2/H2O2/UV-A processes.

    Science.gov (United States)

    Bosio, Morgana; Satyro, Suéllen; Bassin, João Paulo; Saggioro, Enrico; Dezotti, Márcia

    2018-05-01

    Pharmaceutically active compounds are carried into aquatic bodies along with domestic sewage, industrial and agricultural wastewater discharges. Psychotropic drugs, which can be toxic to the biota, have been detected in natural waters in different parts of the world. Conventional water treatments, such as activated sludge, do not properly remove these recalcitrant substances, so the development of processes able to eliminate these compounds becomes very important. Advanced oxidation processes are considered clean technologies, capable of achieving high rates of organic compounds degradation, and can be an efficient alternative to conventional treatments. In this study, the degradation of alprazolam, clonazepam, diazepam, lorazepam, and carbamazepine was evaluated through TiO 2 /UV-A, H 2 O 2 /UV-A, and TiO 2 /H 2 O 2 /UV-A, using sunlight and artificial irradiation. While using TiO 2 in suspension, best results were found at [TiO 2 ] = 0.1 g L -1 . H 2 O 2 /UV-A displayed better results under acidic conditions, achieving from 60 to 80% of removal. When WWTP was used, degradation decreased around 50% for both processes, TiO 2 /UV-A and H 2 O 2 /UV-A, indicating a strong matrix effect. The combination of both processes was shown to be an adequate approach, since removal increased up to 90%. H 2 O 2 /UV-A was used for disinfecting the aqueous matrices, while mineralization was obtained by TiO 2 -photocatalysis.

  16. Respiratory tract tumors in Syrian hamsters following inhalation of Pu--ZrO2 particles

    International Nuclear Information System (INIS)

    Thomas, R.G.; Smith, D.M.

    1979-01-01

    Inhalation of radionuclide-bearing particles remains one of the most intensely pursued problems concerning the nuclear industry. This route of entry is generally accepted as the most probable, in case of human exposure, with ingestion being the other prominent source of concern. Many laboratory investigations, such as those reported here, continue to evaluate the possible consequences that may present health problems to the public domain. Syrian hamsters of both sexes received either inhaled (INH) PuO 2 /ZrO 2 particles, intravenous (IV) PuO 2 /ZrO 2 microspheres, a combination of INH PuO 2 /ZrO 2 particles and injected PuO 2 /ZrO 2 microspheres, or no radionuclides (controls). The INH particles and IV microspheres were tagged with γ-emitting 57 Co to facilitate whole body counting and establishment of retention curves. Total lung burdens ranged from 8 nCi to 143 nCi. Significant numbers of primary lung tumors (5 to 50% per group) were induced in those animals that received INH exposures. Additional α radiation administered via Pu-laden IV microspheres had little or no effect on tumor production or nonneoplastic, degenerative changes in the respiratory tract

  17. Enhanced Photocatalytic Activity of ZrO2-SiO2 Nanoparticles by Platinum Doping

    Directory of Open Access Journals (Sweden)

    Mohammad W. Kadi

    2013-01-01

    Full Text Available ZrO2-SiO2 mixed oxides were prepared via the sol-gel method. Photo-assisted deposition was utilized for doping the prepared mixed oxide with 0.1, 0.2, 0.3, and 0.4 wt% of Pt. XRD spectra showed that doping did not result in the incorporation of Pt within the crystal structure of the material. UV-reflectance spectrometry showed that the band gap of ZrO2-SiO2 decreased from 3.04 eV to 2.48 eV with 0.4 wt% Pt doping. The results show a specific surface area increase of 20%. Enhanced photocatalysis of Pt/ZrO2-SiO2 was successfully tested on photo degradation of cyanide under illumination of visible light. 100% conversion was achieved within 20 min with 0.3 wt% of Pt doped ZrO2-SiO2.

  18. PAC study in the HfO2-SiO2 system

    International Nuclear Information System (INIS)

    Chain, C.Y.; Damonte, L.C.; Ferrari, S.; Munoz, E.; Torres, C. Rodriguez; Pasquevich, A.F.

    2010-01-01

    A high-k HfO 2 /SiO 2 gate stack is taking the place of SiO 2 as a gate dielectric in field effect transistors. This fact makes the study of the solid-state reaction between these oxides very important. Nanostructure characterization of a high-energy ball milled and post-annealed equimolar HfO 2 and amorphous SiO 2 powder mixture has been carried out by perturbed angular correlations (PAC) technique. The study was complemented with X-ray diffraction and positron annihilation lifetime spectroscopy (PALS). The experimental results revealed that the ball milling of equimolar mixtures increases the defects concentration in hafnium oxide. No solid-state reaction occurred even after 8 h of milling. The formation of HfSiO 4 (hafnon) was observed in the milled blends annealed at high temperatures.The PAC results of the milled samples are compared with those obtained for pure m-ZrO 2 subjected to high-energy ball milling and with reported microstructure data for the system ZrO 2 -SiO 2 .

  19. Preparation and characterization of Fe–V/TiO2–SiO2 nanocatalyst ...

    Indian Academy of Sciences (India)

    Administrator

    to silica mole ratio, synthesis temperature and heating rate of calcination on the structure ... 2 wt% of zinc (all on weight percent) supported on TiO2–SiO2 with synthesis temperature of ... (TEOS) and titanium isopropoxide (TIP) have been dis-.

  20. Synthesis, Characterization and Properties of CeO2-doped TiO2 Composite Nanocrystals

    Directory of Open Access Journals (Sweden)

    Oman ZUAS

    2013-12-01

    Full Text Available Pure TiO2 and CeO2-doped TiO2 (3 % CeO2-97 %TiO2 composite nanocrystals were synthesized via co-precipitation method and characterized using TGA, XRD, FTIR, DR-UV-vis and TEM. The XRD data revealed that the phase structure of the synthesized samples was mainly in pure anatase having crystallite size in the range of 7 nm – 11 nm. Spherical shapes with moderate aggregation of the crystal particles were observed under the TEM observation. The presence of the CeO2 at TiO2 site has not only affected morphologically but also induced the electronic property of the TiO2 by lowering the band gap energy from 3.29 eV (Eg-Ti to 3.15 eV (Eg-CeTi. Performance evaluation of the synthesized samples showed that both samples have a strong adsorption capacity toward Congo red (CR dye in aqueous solution at room temperature experiment, where  the capacity of the CeTi was higher than the Ti sample. Based on DR-UV data, the synthesized samples obtained in this study may also become promising catalysts for photo-assisted removal of synthetic dye in aqueous solution. DOI: http://dx.doi.org/10.5755/j01.ms.19.4.2732

  1. Preparation of TiO2-SiO2 composite photocatalysts for environmental applications

    Czech Academy of Sciences Publication Activity Database

    Paušová, Š.; Krýsa, J.; Jirkovský, Jaromír; Prevot, V.; Mailhot, G.

    2014-01-01

    Roč. 89, č. 8 (2014), s. 1129-1135 ISSN 0268-2575 Institutional support: RVO:61388955 Keywords : photocatalysis * TiO2/SiO2 * composite Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.349, year: 2014

  2. Catalytic combustion of trichloroethylene over TiO2-SiO2 supported catalysts

    NARCIS (Netherlands)

    Kulazynski, M.; van Ommen, J.G.; Trawczynski, J.; Walendziewski, J.

    2002-01-01

    Combustion of trichloroethylene (TCE) on Cr2O3, V2O5, Pt or Pd catalysts supported on TiO2-SiO2 as a carrier has been investigated. It was found that oxide catalysts are very active but their activity quickly diminishes due to loss of the active component, especially at higher reaction temperatures

  3. Activity and Selectivity for O-2 Reduction to H2O2 on Transition Metal Surfaces

    DEFF Research Database (Denmark)

    Siahrostami, Samira; Verdaguer Casadevall, Arnau; Karamad, Mohammadreza

    2013-01-01

    Industrially viable electrochemical production of H2O2 requires active, selective and stable electrocatalyst materials to catalyse the oxygen reduction reaction to H2O2. On the basis of density functional theory calculations, we explain why single site catalysts such as Pd/Au show improved...

  4. Promoting effect of CeO 2 on cyclohexanol conversion over CeO 2

    Indian Academy of Sciences (India)

    Abstract. CeO2-ZnO materials were prepared by amorphous citrate process and characterized by TGA, XRD, UV-DRS and surface area measurements. TGA showed that the citrate precursors decompose in the range 350-550°C producing CeO2-containing catalytic materials. XRD and DRS results indicated the formation of ...

  5. Dependence of Photocatalytic Activity of TiO2-SiO2 Nanopowders

    Directory of Open Access Journals (Sweden)

    M. Riazian

    2014-10-01

    Full Text Available Structural properties and chemical composition change the photocatalytic activity in TiO2-SiO2 nanopowder composite. The SiO2-TiO2 nanostructure is synthesized based on sol–gel method. The nanoparticles are characterized by x-ray fluorescents (XRF, x- ray diffraction (XRD, tunneling electron microscopy (TEM, field emission scanning electron microscopy (FE-SEM, UV-vis. Spectrophotometer and furrier transmission create infrared absorption (FTIR techniques. The rate constant k for the degradation of methylen blue in its aqueous solution under UV irradiation is determined as a measure of photocatalytic activity. Dependence between photocatalytic activity and SiO2 content in the composite is determined. Rate constant k is found dependent on the content of SiO2 in the composite that calcined at 900 oC. The addition of low composition SiO2 to the TiO2 matrix (lower than 45% enhances the photocatalytic activity due to thermal stability and increasing in the surface area. The effects of chemical compositions on the surface topography and the crystallization of phases are studied.

  6. Thermoelectric Properties in the TiO2/SnO2 System

    Science.gov (United States)

    Dynys, F.; Sayir, A.; Sehirlioglu, A.; Berger, M.

    2009-01-01

    Nanotechnology has provided a new interest in thermoelectric technology. A thermodynamically driven process is one approach in achieving nanostructures in bulk materials. TiO2/SnO2 system exhibits a large spinodal region with exceptional stable phase separated microstructures up to 1400 C. Fabricated TiO2/SnO2 nanocomposites exhibit n-type behavior with Seebeck coefficients greater than -300 .V/K. Composites exhibit good thermal conductance in the range of 7 to 1 W/mK. Dopant additions have not achieved high electrical conductivity (<1000 S/m). Formation of oxygen deficient composites, TixSn1-xO2-y, can change the electrical conductivity by four orders of magnitude. Achieving higher thermoelectric ZT by oxygen deficiency is being explored. Seebeck coeffcient, thermal conductivity, electrical conductance and microstructure will be discussed in relation to composition and doping.

  7. V-dotO2max prediction from multi-frequency bioelectrical impedance analysis

    International Nuclear Information System (INIS)

    Stahn, Alexander; Strobel, Günther; Terblanche, Elmarie

    2008-01-01

    Bioelectrical impedance analysis (BIA) has been shown to be highly related to skeletal muscle mass and blood volume, both of which are important determinants of maximal oxygen uptake (V-dotO 2max ). The aim of the present study was therefore to investigate the ability of whole-body and segmental multi-frequency BIA to improve current nonexercise V-dotO 2max prediction models. Data for V-dotO 2max (mL min −1 ), anthropometry, self-reported physical activity (PA-R) and BIA were collected in 115 men and women. Multiple linear regression analysis (MLR) was used to develop the most parsimonious prediction model. Segmental BIA was not superior to whole-body measurements. Correlation coefficients between V-dotO 2max and resistance indices were significantly higher at 500 kHz compared to 50 kHz (p 2max (r = 0.89). After adjusting for age, gender and PA-R, MLR revealed that the inclusion of intracellular resistance index was slightly, but significantly (p 2max ( −1 ). In short, whole-body BIA marginally improves the accuracy of nonexercise V-dotO 2max prediction models and its advantage is most pronounced in individuals with particularly low V-dotO 2max

  8. Electrochemical and optical properties of CeO2-SnO2 and CeO2-SnO2:X (X = Li, C, Si films

    Directory of Open Access Journals (Sweden)

    Berton Marcos A.C.

    2001-01-01

    Full Text Available Thin solid films of CeO2-SnO2 (17 mol% Sn and CeO2-SnO2:X (X = Li, C and Si were prepared by the sol-gel route, using an aqueous-based process. The addition of Li, C and Si to the precursor solution leads to films with different electrochemical performances. The films were deposited by the dip-coating technique on ITO coated glass (Donnelly Glass at a speed of 10 cm/min and submitted to a final thermal treatment at 450 °C during 10 min in air. The electrochemical and optical properties of the films were determined from the cyclic voltammetry and chronoamperometry measurements using 0.1 M LiOH as supporting electrolyte. The ion storage capacity of the films was investigated using in situ spectroelectrochemical method and during the insertion/extraction process the films remained transparent. The powders were characterized by thermal analysis (DSC/TGA and X-ray diffraction.

  9. Lattice dynamics of ThO2

    International Nuclear Information System (INIS)

    Gupta, M.K.; Goel, Prabhatasree; Mittal, R.; Choudhury, N.; Chaplot, S.L.

    2012-01-01

    Thorium oxide finds application in nuclear industry. It is also used as a solid state electrolyte and an optical component material. ThO 2 is found in fluorite Fm3m structure. Actinide oxides are found to undergo superionic transition at elevated temperatures, when oxygen atoms start showing liquid like diffusion behaviour

  10. Synthesis, characterization and electroanalytical application of a new SiO2/SnO2 carbon ceramic electrode

    International Nuclear Information System (INIS)

    Arguello, Jacqueline; Magosso, Herica A.; Landers, Richard; Pimentel, Vinicius L.; Gushikem, Yoshitaka

    2010-01-01

    A new SiO 2 /SnO 2 carbon ceramic composite was prepared by the sol-gel method, and its potential application in electrochemistry as a novel electrode material has been studied. The prepared xerogel was structurally and electrochemically characterized by scanning electron microscopy coupled to energy dispersive spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and cyclic voltammetry. The composite was pressed in a rigid disk-shape and used as a conductive substrate to immobilize a water-soluble organic-inorganic hybrid polymer, 3-n-propyl-4-picolinium chloride silsesquioxane. The oxidation of nitrite was studied on this polymer film coated electrode in aqueous solution using cyclic voltammetry and differential pulse voltammetry. This modified electrode exhibited a better defined voltammetric peak shifted negatively about 60 mV. The linear detection limit found for nitrite was from 1.3 x 10 -5 to 1.3 x 10 -3 mol l -1 and the detection limit was 3.3 x 10 -6 mol l -1 .

  11. TiO2/Cu2O composite based on TiO2 NTPC photoanode for photoelectrochemical (PEC) water splitting under visible light

    KAUST Repository

    Shi, Le

    2015-05-01

    Water splitting through photoelectrochemical reaction is widely regarded as a major method to generate H2 , a promising source of renewable energy to deal with the energy crisis faced up to human being. Efficient exploitation of visible light in practice of water splitting with pure TiO2 material, one of the most popular semiconductor material used for photoelectrochemical water splitting, is still challenging. One dimensional TiO2 nanotubes is highly desired with its less recombination with the short distance for charge carrier diffusion and light-scattering properties. This work is based on TiO2 NTPC electrode by the optimized two-step anodization method from our group. A highly crystalized p-type Cu2O layer was deposited by optimized pulse potentiostatic electrochemical deposition onto TiO2 nanotubes to enhance the visible light absorption of a pure p-type TiO2 substrate and to build a p-n junction at the interface to improve the PEC performance. However, because of the real photocurrent of Cu2O is far away from its theoretical limit and also poor stability in the aqueous environment, a design of rGO medium layer was added between TiO2 nanotube and Cu2O layer to enhance the photogenerated electrons and holes separation, extend charge carrier diffusion length (in comparison with those of conventional pure TiO2 or Cu2O materials) which could significantly increase photocurrent to 0.65 mA/cm2 under visible light illumination (>420 nm) and also largely improve the stability of Cu2O layer, finally lead to an enhancement of water splitting performance.

  12. Effects of Partially Ionised Medical Oxygen, Especially with O2•−, in Vibration White Finger Patients

    Directory of Open Access Journals (Sweden)

    Slavomír Perečinský

    2014-05-01

    Full Text Available A major symptom of hand-arm vibration syndrome is a secondary Raynaud’s phenomenon—vibration white finger (VWF—which results from a vasospasm of the digital arteries caused by work with vibration devices leading to occupational disease. Pharmacotherapy of VWF is often ineffective or has adverse effects. The aim of this work was to verify the influence of inhalation of partially ionized oxygen (O2•− on peripheral blood vessels in the hands of patients with VWF. Ninety one (91patients with VWF underwent four-finger adsorption plethysmography, and the pulse wave amplitude was recorded expressed in numeric parameters—called the native record. Next, a cold water test was conducted following with second plethysmography. The patients were divided in to the three groups. First and second inhaled 20-min of ionized oxygen O2•− or oxygen O2 respectively. Thirth group was control without treatment. All three groups a follow-up third plethysmography—the post-therapy record. Changes in the pulse wave amplitudes were evaluated. Inpatients group inhaling O2•− a modest increase of pulse wave amplitude was observed compared to the native record; patients inhaling medical oxygen O2 and the control showed a undesirable decline of pulse wave amplitude in VWF fingers. Strong vasodilatation were more frequent in the group inhaling O2•− compare to O2 (p < 0.05. Peripheral vasodilatation achieved by inhalation of O2•− could be used for VWF treatment without undesirable side effect in hospital as well as at home environment.

  13. Metal-to-Insulator Transition in Anatase TiO2 Thin Films Induced by Growth Rate Modulation

    International Nuclear Information System (INIS)

    Tachikawa, Takashi

    2012-01-01

    We demonstrate control of the carrier density of single phase anatase TiO 2 thin films by nearly two orders of magnitude by modulating the growth kinetics during pulsed laser deposition, under fixed thermodynamic conditions. The resistivity and the intensity of the photoluminescence spectra of these TiO 2 samples, both of which correlate with the number of oxygen vacancies, are shown to depend strongly on the growth rate. A quantitative model is used to explain the carrier density changes.

  14. Atmospheric chemistry of dimethyl sulfide. Kinetics of the CH3SCH2O2 + NO2 reaction in the gas phase at 296 K

    DEFF Research Database (Denmark)

    Nielsen, O.J.; Sehested, J.; Wallington, T.J.

    1995-01-01

    The pulse radiolysis of SF6/CH3SCH3/O-2/NO2 gas mixtures was used to generate CH3SCH2O2 radicals in the presence of NO2. By monitoring the rate of NO2 decay using its absorption at 400 nm, rate constants for the reaction of CH3SCH2O2 radicals with NO2 were measured to be (9.2 +/- 0.9) x 10...

  15. Low-debris, efficient laser-produced plasma extreme ultraviolet source by use of a regenerative liquid microjet target containing tin dioxide (SnO2) nanoparticles

    Science.gov (United States)

    Higashiguchi, Takeshi; Dojyo, Naoto; Hamada, Masaya; Sasaki, Wataru; Kubodera, Shoichi

    2006-05-01

    We demonstrated a low-debris, efficient laser-produced plasma extreme ultraviolet (EUV) source by use of a regenerative liquid microjet target containing tin-dioxide (SnO2) nanoparticles. By using a low SnO2 concentration (6%) solution and dual laser pulses for the plasma control, we observed the EUV conversion efficiency of 1.2% with undetectable debris.

  16. Low-debris, efficient laser-produced plasma extreme ultraviolet source by use of a regenerative liquid microjet target containing tin dioxide (SnO2) nanoparticles

    International Nuclear Information System (INIS)

    Higashiguchi, Takeshi; Dojyo, Naoto; Hamada, Masaya; Sasaki, Wataru; Kubodera, Shoichi

    2006-01-01

    We demonstrated a low-debris, efficient laser-produced plasma extreme ultraviolet (EUV) source by use of a regenerative liquid microjet target containing tin-dioxide (SnO 2 ) nanoparticles. By using a low SnO 2 concentration (6%) solution and dual laser pulses for the plasma control, we observed the EUV conversion efficiency of 1.2% with undetectable debris

  17. Single-pulse and multi-pulse femtosecond laser damage of optical single films

    International Nuclear Information System (INIS)

    Yuan Lei; Zhao Yuan'an; He Hongbo; Shao Jianda; Fan Zhengxiu

    2006-01-01

    Laser-induced damage of a single 500 nm HfO 2 film and a single 500 nm ZrO 2 film were studied with single- and multi-pulse femtosecond laser. The laser-induced damage thresholds (LIDT) of both samples by the 1-on-1 method and the 1000-on-1 method were reported. It was discovered that the LIDT of the HfO 2 single film was higher than that of the ZrO 2 single film by both test methods, which was explained by simple Keldysh's multiphoton ionization theory. The LIDT of multi-pulse was lower than that of single-pulse for both samples as a result of accumulative effect. (authors)

  18. Toxicity of inhaled 238PuO2 II

    International Nuclear Information System (INIS)

    Muggenburg, B.A.; Mewhinney, J.A.; Merickel, B.S.; Boecker, B.B.; Hahn, F.F.; Guilmette, R.A.; Mauderly, J.L.; McClellan, R.O.

    1980-01-01

    Studies are in progress to determine dose-response relationships for inhaled 238 PuO 2 . Beagle dogs were given a single, brief, nose-only inhalation exposure to aerosols of monodisperse particles of 238 PuO 2 . Aerosols of two sizes were used, 1.5 μm aerodynamic diameter (AD) and 3.0 μm AD. Dogs were exposed to achieve initial lung burdens of 0.56, 0.28, 0.14, 0.07, 0.03 or 0.01 μCi 238 PuO 2 /kg body weight. Twelve dogs were exposed at each activity level to each aerosol particle size. The local dose around each 3.0 μm AD particle was 10 times higher than the local dose around 1.5 μm AD particles, but the dose averaged over the whole lung was the same at each activity level for both particle sizes. The lung retention of 238 Pu was divided into two phases of clearance. During the first 100 days after exposure, the average retention half-time for 238 Pu in the lung was 310 days. When the solubility changed due to particle breakup, the retention half-time decreased to 180 days during the period from 1OO to 1,500 days after exposure. The first biological effects observed were lymphopenia and neutropenia in peripheral blood. To date, 28 Beagle dogs have died at times from 536 to 1683 days after exposure. Initial lung burdens for the dead dogs ranged from 0.18 to 2.2 μCi 238 Pu/kg body weight. Nine died with radiation pneumonitis and pulmonary fibrosis, 10 died with lung tumors and 19 dogs died with bone tumors. There are 116 exposed and 22 control dogs surviving and under observation. Current patterns of dose versus response are discussed. (author)

  19. Photoemission study on electrical dipole at SiO_2/Si and HfO_2/SiO_2 interfaces

    International Nuclear Information System (INIS)

    Fujimura, Nobuyuki; Ohta, Akio; Ikeda, Mitsuhisa; Makihara, Katsunori; Miyazaki, Seiichi

    2017-01-01

    Electrical dipole at SiO_2/Si and HfO_2/SiO_2 interfaces have been investigated by X-ray photoelectron spectroscopy (XPS) under monochromatized Al Kα radiation. From the analysis of the cut-off energy for secondary photoelectrons measured at each thinning step of a dielectric layer by wet-chemical etching, an abrupt potential change caused by electrical dipole at SiO_2/Si and HfO_2/SiO_2 interfaces has been clearly detected. Al-gate MOS capacitors with thermally-grown SiO_2 and a HfO_2/SiO_2 dielectric stack were fabricated to evaluate the Al work function from the flat band voltage shift of capacitance-voltage (C-V) characteristics. Comparing the results of XPS and C-V measurements, we have verified that electrical dipole formed at the interface can be directly measured by photoemission measurements. (author)

  20. Laser induced forward transfer of SnO2 for sensing applications using different precursors systems

    Science.gov (United States)

    Mattle, Thomas; Hintennach, Andreas; Lippert, Thomas; Wokaun, Alexander

    2013-02-01

    This paper presents the transfer of SnO2 by laser induced forward transfer (LIFT) for gas sensor applications. Different donor substrates of SnO2 with and without triazene polymer (TP) as a dynamic release layer were prepared. Transferring these films under different conditions were evaluated by optical microscopy and functionality. Transfers of sputtered SnO2 films do not lead to satisfactory results and transfers of SnO2 nanoparticles are difficult. Transfers of SnO2 nanoparticles can only be achieved when applying a second laser pulse to the already transferred material, which improves the adhesion resulting in a complete pixel. A new approach of decomposing the transfer material during LIFT transfer was developed. Donor films based on UV absorbing metal complex precursors namely, SnCl2(acac)2 were prepared and transferred using the LIFT technique. Transfer conditions were optimized for the different systems, which were deposited onto sensor-like microstructures. The conductivity of the transferred material at temperatures of about 400 ∘C are in a range usable for SnO2 gas sensors. First sensing tests were carried out and the transferred material proved to change conductivity when exposed to ethanol, acetone, and methane.

  1. O2(b1∑+g) relaxation in active medium of oxygen-iodine laser

    Science.gov (United States)

    Tolstov, G. I.; Zagidullin, M. V.; Khvatov, N. A.; Medvedkov, I. A.; Mikheyev, P. A.

    2018-04-01

    Rate constants for the removal of O2 b1∑+g by collisions with O2, N2, CO2 and H2O have been determined at temperature 297 K. O2(b1 ∑+g) was excited by pulses from a tunable dye laser, and the deactivation kinetics were followed by observing the temporal behavior of the b1∑+g - X3∑-g fluorescence. The removal rate constants for CO2, N2 and H2O were not strongly dependent on temperature, and could be represented by the expressions kCO2=(1.8+/-0.05)×10-16 kN2=(2.2 +/- 0.2)×10-15, and kH2O=(6.12+/-0.67)×10-12 cm3 molecule-1 s-1. Rate constant for O2(b1∑+ ) removal by O2(X), being orders of magnitude lower, represented by the fitted expression kO2=(3.67 +/- 0.06)×10-17 cm3 molecule-1 s-1. All of the rate constants measured at room temperature were found to be in good agreement with previously reported values.

  2. Au-TiO2/Chit modified sensor for electrochemical detection of trace organophosphates insecticides.

    Science.gov (United States)

    Qu, Yunhe; Min, Hong; Wei, Yinyin; Xiao, Fei; Shi, Guoyue; Li, Xiaohua; Jin, Litong

    2008-08-15

    In this paper, Au-TiO2/Chit modified electrode was prepared with Au-TiO2 nanocomposite (Au-TiO2) and Chitosan (Chit) as a conjunct. The Au-TiO2 nanocomposite and the films were characterized by electrochemical and spectroscopy methods. A set of experimental conditions was also optimized for the film's fabrication. The electrochemical and electrocatalytic behaviors of Au-TiO2/Chit modified electrode to trace organophosphates (OPs) insecticides such as parathion were discussed in this work. By differential pulse voltammetry (DPV) measurement, the current responses of Au-TiO2/Chit modified electrode were linear with parathion concentration ranging from 1.0 ng/ml to 7.0 x 10(3)ng/ml with the detection limit of 0.5 ng/ml. In order to evaluate the performance of the detection system, we also examined the real samples successfully in this work. It exhibited a sensitive, rapid and easy-to-use method for the fast determination of trace OPs insecticides.

  3. Characterization of TiO2–MnO2 composite electrodes synthesized using spark plasma sintering technique

    CSIR Research Space (South Africa)

    Tshephe, TS

    2015-03-01

    Full Text Available and electrochemical stability of the resulting materials were investigated. Relative densities of 99.33% and 98.49% were obtained for 90TiO2–10MnO2 and 80TiO2–10MnO2 when ball was incorporated. The 90TiO2–10MnO2 powder mixed with balls had its Vickers hardness value...

  4. Study of O2(1Δ) production by nuclear pumping. Final report, 12 April 1982-30 June 1983

    International Nuclear Information System (INIS)

    Miley, G.H.

    1983-01-01

    Studies concerned with the possible use of nuclear pumping to produce O 2 ( 1 Δ) are described. The goal is to develop methods to produce adequate O 2 ( 1 Δ) to use in an O 2 -I 2 mixing-type laser. Although the O 2 ( 1 Δ) concentrations generated in the nuclear induced discharge are too small for the operation of an iodine laser, one of the most promising approaches identified involves the initial production of ozone by nuclear pumping of a high pressure (approx. 5 atm) O 2 -He mixture. The ozone mixture is then photodecomposed by use of a KrF nuclear pumped flashlamp. Based on a combination of experimental and theoretical data, it is estimated that O 2 ( 1 Δ)/O 2 ratios > 0.3 can be produced this way with approx. 7 Torr of O 2 ( 1 Δ) in a mixture initially containing 2 Torr of O 3 . This is well above the minimum requirements for operation of an iodine laser. Experimental results of nuclear pumping O 2 -noble gas mixtures in a pulsed TRIGA reactor are described and scaling relations developed

  5. Developmental programming of O2 sensing by neonatal intermittent hypoxia via epigenetic mechanisms

    OpenAIRE

    Nanduri, Jayasri; Prabhakar, Nanduri R.

    2012-01-01

    Recurrent apnea with intermittent hypoxia (IH) is a major clinical problem in infants born preterm. Carotid body chemo-reflex and catecholamine secretion from adrenal medullary chromaffin cells (AMC) are important for maintenance of cardio-respiratory homeostasis during hypoxia. This article highlights studies on the effects of IH on O2 sensing by the carotid body and AMC in neonatal rodents. Neonatal IH augments hypoxia-evoked carotid body sensory excitation and catecholamine secretion from ...

  6. Enhanced Activity and Durability of Nanosized Pt-SnO2/IrO2/CNTs Catalyst for Methanol Electrooxidation.

    Science.gov (United States)

    Wang, Hongjuan; Wang, Xiaohui; Zheng, Jiadao; Peng, Feng; Yu, Hao

    2015-05-01

    Pt-SnO2/IrO2/CNTs anode catalyst for direct methanol fuel cell was designed and prepared with IrO2/CNTs as support for the subsequent immobilization of Pt and SnO2 at the same time. The structure of the catalysts and their catalytic performance in methanol electrooxidation were investigated and the roles of IrO2 and SnO2 in methanol electrooxidation were discussed as well. Results show that Pt-SnO2/IrO2/CNTs catalyst exhibits the best activity and durability for methanol electrooxidation when compared with Pt/CNTs, Pt/IrO2/CNTs and Pt-SnO2/CNTs. According to the results of electrochemical tests and physicochemical characterizations, the enhancements of Pt-SnO2/IrO2/CNTs were attributed to the special properties of IrO2 and SnO2, in which IrO2 mainly increases the methanol oxidation activity and SnO2 mainly improves the CO oxidation ability and durability. Therefore, Pt-SnO2/IrO2/CNTs exhibits excellent performance for methanol oxidation with higher electrocatalytic activity (I(f) of 1054 A g(Pt(-1)) and powerful anti-poisoning ability (the onset potential for CO oxidation of 0.3 V) and outstanding durability (the sustained time t in CP of 617 s), revealing a suitable anode catalyst for DMFCs.

  7. CeO2-stabilized tetragonal ZrO2 polycrystals (Ce-TZP ceramics)

    International Nuclear Information System (INIS)

    Andrade Nono, M.C. de.

    1990-12-01

    This work presents the development and the characterization of CeO 2 -stabilized tetragonal ZrO 2 polycrystals (Ce-TZP ceramics), since it is considered candidate material for applications as structural high performance ceramics. Sintered ceramics were fabricated from mixtures of powders containing different CeO 2 content prepared by conventional and nonconventional techniques. These powders and their resultant sintered ceramics were specified by chemical and physical characterization, compactation state and mechanical properties. The chemical characteristics were determined by chemical analysis and the physical characteristics were evaluated by phase content, particle and agglomerate size and aspect, and powder porosity. (author)

  8. Photocatalytic performance of TiO2 catalysts modified by H3PW12O40, ZrO2 and CeO2

    Institute of Scientific and Technical Information of China (English)

    CAI Tiejun; LIAO Yuchao; PENG Zhenshan; LONG Yunfei; WEI Zongyuan; DENG Qian

    2009-01-01

    The binary composite photo-catalysts CeO2/TiO2, ZrO2/TiO2 and the ternary composite photo-catalysts H3PW12O40-CeO2/TiO2,H2PW12O40-ZrO2/TiO2 were prepared by sol-gel method. The catalysts were characterized by thermogravimetric-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photocatalyfic elimination of methanol was used as model reaction to evaluate the photocatalytic activity of the composite catalysts under ultraviolet light irradiation. The effects of doped content, activation temperature, time, initial concentration of methanol and gas flow rate on the catalytic activity were investigated. The results showed that after doping a certain amount of CeO2 and ZrO2, crystaniTation process of TiO2 was restrained, particles of catalysts are smaller and more uniform. Doping ZrO2 not only significantly improved the catalytic activity, but also increased thermal stability. Doping H3PW12O40 also enhanced the catalytic activity. The catalytic activities of binary and ternary composite photocatalysts were significantly higher than tin-doped TiO2. The dynamics law of photocatalytic reaction over the binary CeO2/TiO2 and ZrO2/TiO2 catalysts has been studied. The activation energy 15.627 and 15.631 kJ/mol and pre-exponential factors 0.5176 and 0.9899 s-1 over each corresponding catalyst were obtained. This reaction accords to the first order dynamics law.

  9. A short-breath-hold technique for lung pO2 mapping with 3He MRI.

    Science.gov (United States)

    Miller, G Wilson; Mugler, John P; Altes, Talissa A; Cai, Jing; Mata, Jaime F; de Lange, Eduard E; Tobias, William A; Cates, Gordon D; Brookeman, James R

    2010-01-01

    A pulse-sequence strategy was developed for generating regional maps of alveolar oxygen partial pressure (pO2) in a single 6-sec breath hold, for use in human subjects with impaired lung function. Like previously described methods, pO2 values are obtained by measuring the oxygen-induced T1 relaxation of inhaled hyperpolarized 3He. Unlike other methods, only two 3He images are acquired: one with reverse-centric and the other with centric phase-encoding order. This phase-encoding arrangement minimizes the effects of regional flip-angle variations, so that an accurate map of instantaneous pO2 can be calculated from two images acquired a few seconds apart. By combining this phase-encoding strategy with variable flip angles, the vast majority of the hyperpolarized magnetization goes directly into the T1 measurement, minimizing noise in the resulting pO2 map. The short-breath-hold pulse sequence was tested in phantoms containing known O2 concentrations. The mean difference between measured and prepared pO2 values was 1 mm Hg. The method was also tested in four healthy volunteers and three lung-transplant patients. Maps of healthy subjects were largely uniform, whereas focal regions of abnormal pO2 were observed in diseased subjects. Mean pO2 values varied with inhaled O2 concentration. Mean pO2 was consistent with normal steady-state values in subjects who inhaled 3He diluted only with room air. Copyright (c) 2009 Wiley-Liss, Inc.

  10. Fabrication of hydrogen peroxide biosensor based on Ni doped SnO2 nanoparticles.

    Science.gov (United States)

    Lavanya, N; Radhakrishnan, S; Sekar, C

    2012-01-01

    Ni doped SnO(2) nanoparticles (0-5 wt%) have been prepared by a simple microwave irradiation (2.45 GHz) method. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies confirmed the formation of rutile structure with space group (P(42)/mnm) and nanocrystalline nature of the products with spherical morphology. Direct electrochemistry of horseradish peroxidase (HRP)/nano-SnO(2) composite has been studied. The immobilized enzyme retained its bioactivity, exhibited a surface confined, reversible one-proton and one-electron transfer reaction, and had good stability, activity and a fast heterogeneous electron transfer rate. A significant enzyme loading (3.374×10(-10) mol cm(-2)) has been obtained on nano-Ni doped SnO(2) as compared to the bare glassy carbon (GC) and nano-SnO(2) modified surfaces. This HRP/nano-Ni-SnO(2) film has been used for sensitive detection of H(2)O(2) by differential pulse voltammetry (DPV), which exhibited a wider linearity range from 1.0×10(-7) to 3.0×10(-4)M (R=0.9897) with a detection limit of 43 nM. The apparent Michaelis-Menten constant (K(M)(app)) of HRP on the nano-Ni-SnO(2) was estimated as 0.221 mM. This excellent performance of the fabricated biosensor is attributed to large surface-to-volume ratio and Ni doping into SnO(2) which facilitate the direct electron transfer between the redox enzyme and the surface of electrode. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. 53Cr NMR study of CuCrO2 multiferroic

    Science.gov (United States)

    Smol'nikov, A. G.; Ogloblichev, V. V.; Verkhovskii, S. V.; Mikhalev, K. N.; Yakubovskii, A. Yu.; Kumagai, K.; Furukawa, Y.; Sadykov, A. F.; Piskunov, Yu. V.; Gerashchenko, A. P.; Barilo, S. N.; Shiryaev, S. V.

    2015-11-01

    The magnetically ordered phase of the CuCrO2 single crystal has been studied by the nuclear magnetic resonance (NMR) method on 53Cr nuclei in the absence of an external magnetic field. The 53Cr NMR spectrum is observed in the frequency range νres = 61-66 MHz. The shape of the spectrum depends on the delay tdel between pulses in the pulse sequence τπ/2- t del-τπ- t del-echo. The spin-spin and spin-lattice relaxation times have been measured. Components of the electric field gradient, hyperfine fields, and the magnetic moment on chromium atoms have been estimated.

  12. TiO2 coated SnO2 nanosheet films for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Cai Fengshi; Yuan Zhihao; Duan Yueqing; Bie Lijian

    2011-01-01

    TiO 2 -coated SnO 2 nanosheet (TiO 2 -SnO 2 NS) films about 300 nm in thickness were fabricated on fluorine-doped tin oxide glass by a two-step process with facile solution-grown approach and subsequent hydrolysis of TiCl 4 aqueous solution. The as-prepared TiO 2 -SnO 2 NSs were characterized by scanning electron microscopy and X-ray diffraction. The performances of the dye-sensitized solar cells (DSCs) with TiO 2 -SnO 2 NSs were analyzed by current-voltage measurements and electrochemical impedance spectroscopy. Experimental results show that the introduction of TiO 2 -SnO 2 NSs can provide an efficient electron transition channel along the SnO 2 nanosheets, increase the short current density, and finally improve the conversion efficiency for the DSCs from 4.52 to 5.71%.

  13. Memory and pressure studies in NaxCoO2 cobaltites

    International Nuclear Information System (INIS)

    Garbarino, G; Bouvier, P; Crichton, W A; Mezouar, M; Regueiro, M Nunez; Lejay, P; Armand, M; Foo, M L; Cava, R J

    2009-01-01

    We present a detailed study on the memory effect results in Na 0.5 paragraph 5CoO 2 single crystals. We analyze the temperature dependence of the nonvolatile current-pulse-induced resistance memory state. These results allow us to have more insight in the mobility of Na + ions induced by current and their effect on the memory effect. We also developed X-ray diffraction studies under pressure at ambient temperature in the N a0.5 CoO 2 powder compound. An orthorhombic to hexagonal phase transition was observed at 9GPa. This transition can be explained taking into account the Na ions displacement between two allowed positions. These structural results allow us to confirm that the non-volatile resistive commutation can be interpreted by the displacement of the Na ions induced by the current pulses.

  14. Memristive and neuromorphic behavior in a LixCoO2 nanobattery

    Science.gov (United States)

    Mai, V. H.; Moradpour, A.; Senzier, P. Auban; Pasquier, C.; Wang, K.; Rozenberg, M. J.; Giapintzakis, J.; Mihailescu, C. N.; Orfanidou, C. M.; Svoukis, E.; Breza, A.; Lioutas, Ch B.; Franger, S.; Revcolevschi, A.; Maroutian, T.; Lecoeur, P.; Aubert, P.; Agnus, G.; Salot, R.; Albouy, P. A.; Weil, R.; Alamarguy, D.; March, K.; Jomard, F.; Chrétien, P.; Schneegans, O.

    2015-01-01

    The phenomenon of resistive switching (RS), which was initially linked to non-volatile resistive memory applications, has recently also been associated with the concept of memristors, whose adjustable multilevel resistance characteristics open up unforeseen perspectives in cognitive computing. Herein, we demonstrate that the resistance states of LixCoO2 thin film-based metal-insulator-metal (MIM) solid-state cells can be tuned by sequential programming voltage pulses, and that these resistance states are dramatically dependent on the pulses input rate, hence emulating biological synapse plasticity. In addition, we identify the underlying electrochemical processes of RS in our MIM cells, which also reveal a nanobattery-like behavior, leading to the generation of electrical signals that bring an unprecedented new dimension to the connection between memristors and neuromorphic systems. Therefore, these LixCoO2-based MIM devices allow for a combination of possibilities, offering new perspectives of usage in nanoelectronics and bio-inspired neuromorphic circuits.

  15. VUV photoionization cross sections of HO2, H2O2, and H2CO.

    Science.gov (United States)

    Dodson, Leah G; Shen, Linhan; Savee, John D; Eddingsaas, Nathan C; Welz, Oliver; Taatjes, Craig A; Osborn, David L; Sander, Stanley P; Okumura, Mitchio

    2015-02-26

    The absolute vacuum ultraviolet (VUV) photoionization spectra of the hydroperoxyl radical (HO2), hydrogen peroxide (H2O2), and formaldehyde (H2CO) have been measured from their first ionization thresholds to 12.008 eV. HO2, H2O2, and H2CO were generated from the oxidation of methanol initiated by pulsed-laser-photolysis of Cl2 in a low-pressure slow flow reactor. Reactants, intermediates, and products were detected by time-resolved multiplexed synchrotron photoionization mass spectrometry. Absolute concentrations were obtained from the time-dependent photoion signals by modeling the kinetics of the methanol oxidation chemistry. Photoionization cross sections were determined at several photon energies relative to the cross section of methanol, which was in turn determined relative to that of propene. These measurements were used to place relative photoionization spectra of HO2, H2O2, and H2CO on an absolute scale, resulting in absolute photoionization spectra.

  16. Magnetic and structural study of Cu-doped TiO2 thin films

    International Nuclear Information System (INIS)

    Torres, C.E. Rodriguez; Golmar, F.; Cabrera, A.F.; Errico, L.; Navarro, A.M. Mudarra; Renteria, M.; Sanchez, F.H.; Duhalde, S.

    2007-01-01

    Transparent pure and Cu-doped (2.5, 5 and 10 at.%) anatase TiO 2 thin films were grown by pulsed laser deposition technique on LaAlO 3 substrates. The samples were structurally characterized by X-ray absorption spectroscopy and X-ray diffraction. The magnetic properties were measured using a SQUID. All films have a FM-like behaviour. In the case of the Cu-doped samples, the magnetic cycles are almost independent of the Cu concentration. Cu atoms are forming CuO and/or substituting Ti in TiO 2 . The thermal treatment in air promotes the CuO segregation. Since CuO is antiferromagnetic, the magnetic signals present in the films could be assigned to Cu substitutionally replacing cations in TiO 2

  17. Fabrication of graphene–TiO2 nanocomposite with improved ...

    Indian Academy of Sciences (India)

    carbon nanocomposite material shows high photocatalytic activity compared with the bare TiO2. However, TiO2 has a high band gap (3.2 eV) and absorb little amount of solar ... tion of titanium dioxide (TiO2)–graphene (GR) (TiO2–GR).

  18. Refractories in the Al2O3-ZrO2-SiO2 system

    International Nuclear Information System (INIS)

    Banerjee, S.P.; Bhadra, A.K.; Sircar, N.R.

    1978-01-01

    The effect of addition of ZrO 2 in different proportions in the refractories of the Al 2 O 3 -SiO 2 system was studied. The investigation was confined to two broad ranges of compositions incorporating zirconia (15-30 percent and 80-85 percent) in the Al 2 O 3 -ZrO 2 -SiO 2 system. The overall attainment of properties is dependent upon the mode of fabrication and firing, and bears a relationship with the phase assemblages and the relative proportion thereof. Of the different characteristics, the trend of dissociation of zircon has been found to be specially significant vis-a-vis the temperature of firing and thermal shock resistance. Reassociation of the dissociated products has been ascribed to bring forth improved resistance to thermal spalling. The different products developed during this investigation are considered to be very promising which find useful applications in view of the properties attained by them. (auth.)

  19. On the Stability of NaO2 in Na-O2 Batteries.

    Science.gov (United States)

    Liu, Chenjuan; Carboni, Marco; Brant, William R; Pan, Ruijun; Hedman, Jonas; Zhu, Jiefang; Gustafsson, Torbjörn; Younesi, Reza

    2018-04-25

    Na-O 2 batteries are regarded as promising candidates for energy storage. They have higher energy efficiency, rate capability, and chemical reversibility than Li-O 2 batteries; in addition, sodium is cheaper and more abundant compared to lithium. However, inconsistent observations and instability of discharge products have inhibited the understanding of the working mechanism of this technology. In this work, we have investigated a number of factors that influence the stability of the discharge products. By means of in operando powder X-ray diffraction study, the influence of oxygen, sodium anode, salt, solvent, and carbon cathode were investigated. The Na metal anode and an ether-based solvent are the main factors that lead to the instability and decomposition of NaO 2 in the cell environment. This fundamental insight brings new information on the working mechanism of Na-O 2 batteries.

  20. Polymer supported organic catalysts for O2 reduction in Li-O2 batteries

    International Nuclear Information System (INIS)

    Weng, Wei; Barile, Christopher J.; Du, Peng; Abouimrane, Ali; Assary, Rajeev S.; Gewirth, Andrew A.; Curtiss, Larry A.; Amine, Khalil

    2014-01-01

    Graphical abstract: - Abstract: A novel organic catalyst has been synthesized that contains an anthraquinone moiety supported on a polymer backbone. This oxygen reduction catalyst was successfully incorporated in the cathode of Li-O 2 batteries. The addition of the anthraquinone-based catalyst improved the cycleability of the Li-O 2 battery when cycled in a tetraethylene glycol dimethyl ether electrolyte. Computational studies coupled with a wide range of analytical techniques including differential electrochemical mass spectrometry, cyclic voltammetry, electrochemical impedence spectroscopy, and X-ray diffraction were used to interrogate the Li-O 2 battery with and without the organic catalyst present. This study suggests that organic catalysts may serve as light and inexpensive alternatives to the precious metals frequently used in Li-O 2 batteries

  1. Design of high quality doped CeO2 solid electrolytes with nanohetero structure

    International Nuclear Information System (INIS)

    Mori, T.; Ou, D.R.; Ye, F.; Drennan, J.

    2006-01-01

    Doped cerium (CeO 2 ) compounds are fluorite related oxides which show oxide ionic conductivity higher than yttria-stabilized zirconia in oxidizing atmosphere. As a consequence of this, a considerable interest has been shown in application of these materials for low (400-650 o C) temperature operation of solid oxide fuel cells (SOFCs). In this paper, our experimental data about the influence of microstructure at the atomic level on electrochemical properties were reviewed in order to develop high quality doped CeO 2 electrolytes in fuel cell applications. Using this data in the present paper, our original idea for a design of nanodomain structure in doped CeO 2 electrolytes was suggested. The nanosized powders and dense sintered bodies of M doped CeO 2 (M:Sm,Gd,La,Y,Yb, and Dy) compounds were fabricated. Also nanostructural features in these specimens were introduced for conclusion of relationship between electrolytic properties and domain structure in doped CeO 2 . It is essential that the electrolytic properties in doped CeO 2 solid electrolytes reflect in changes of microstructure even down to the atomic scale. Accordingly, a combined approach of nanostructure fabrication, electrical measurement and structure characterization was required to develop superior quality doped CeO 2 electrolytes in the fuel cells. (author)

  2. Preparation and Photocatalytic Property of TiO2/Diatomite-Based Porous Ceramics Composite Materials

    Directory of Open Access Journals (Sweden)

    Shuilin Zheng

    2012-01-01

    Full Text Available The diatomite-based porous ceramics was made by low-temperature sintering. Then the nano-TiO2/diatomite-based porous ceramics composite materials were prepared by hydrolysis deposition method with titanium tetrachloride as the precursor of TiO2 and diatomite-based porous as the supporting body of the nano-TiO2. The structure and microscopic appearance of nano-TiO2/diatomite-based porous ceramics composite materials was characterized by XRD and SEM. The photocatalytic property of the composite was investigated by the degradation of malachite green. Results showed that, after calcination at 550°C, TiO2 thin film loaded on the diatomite-based porous ceramics is anatase TiO2 and average grain size of TiO2 is about 10 nm. The degradation ratio of the composite for 5 mg/L malachite green solution reached 86.2% after irradiation for 6 h under ultraviolet.

  3. Internalization of Consumed TiO2 Nanoparticles by a Model Invertebrate Organism

    Directory of Open Access Journals (Sweden)

    Sara Novak

    2012-01-01

    Full Text Available There is little in vivo data concerning the fate of ingested TiO2 nanoparticles (nano-TiO2. We report here experiments aimed at assessing if ingested nano-TiO2 accumulates in the digestive gland epithelium or are internalized elsewhere in the body of the terrestrial isopod crustaceans. The animals (Porcellio scaber, Isopoda, Crustacea fed for 3, 7, or 14 days on food dosed with 100 or 1000 μg nano-TiO2 showed no evidence of internalization of Ti measured by microparticle-induced X-ray emission method. The effect of ingested nanoparticles was measured by conventional toxicity measures such as feeding rate, weight change, and mortality and did not indicate any toxicity. However, cell membrane of digestive glands, measured with a modified method for assessing cell membrane stability, was affected already after 3 days of exposure to 1000 μg nano-TiO2 per gram dry weight of food indicating cytotoxic potential of ingested nanoparticles. Our results confirmed hypothesis on low toxic potential and no internalization of consumed TiO2 nanoparticles by a model invertebrate organism. However, cytological marker unequivocally indicated adverse effect of ingested nano-TiO2. We conclude that the isopod model system could be used for studying the fate and effect of ingested nanoparticles.

  4. Sorption and physical properties of Mn O2-Si O2 composite

    International Nuclear Information System (INIS)

    Labayru M, R.; Correa N, M.; Andalaft J, E.

    1992-01-01

    These results show that the addition of silica improve the sorption and mechanical properties of Mn O 2 -Si O 2 composite. This ion-exchange material has an high Sr adsorption capacity still in the presence of Cs and Al, its capacity being higher than that of commercially available products. The particle size distribution of the ground solid is homogeneous ranging from 90 to 600 μm. The largest particle size fraction is directly proportional to the amount of silica. (author)

  5. Spray deposited CeO2–TiO2 counter electrode for electrochromic ...

    Indian Academy of Sciences (India)

    Abstract. Optically passive thin films of CeO2–TiO2 mixed oxides with molar ratio of Ce/Ti of 0.05 were deposited by the spray pyrolysis technique (SPT) on a glass and fluorine-doped tin oxide (FTO)-coated glass substrates. Precur- sor solution containing cerium nitrate hexahydrate (Ce(NO3)2·6H2O) and titanium ...

  6. Ce O2-Zr O2 powder synthesis by alcohol dehydration of aqueous salt solutions

    International Nuclear Information System (INIS)

    Andrade Nono, M.C. de

    1993-01-01

    A method for the precipitation of Ce O 2 -Zr O 2 powder is reported. It involves the powder synthesis by precipitation from an aqueous of Y and Zr sulphates in ethanol and isopropanol followed by calcination. The powder characteristics and their relations with the green compaction and densification by sintering are shown and discussed. It is observed that the ethanol gives powders with the best compaction and sintering behavior. (author)

  7. Study of Influencing Factors of Dynamic Measurements Based on SnO2 Gas Sensor

    Directory of Open Access Journals (Sweden)

    Jinhuai Liu

    2004-08-01

    Full Text Available Abstract: The gas-sensing behaviour based on a dynamic measurement method of a single SnO2 gas sensor was investigated by comparison with the static measurement. The influencing factors of nonlinear response such as modulation temperature, duty ratio, heating waveform (rectangular, sinusoidal, saw-tooth, pulse, etc. were also studied. Experimental data showed that temperature was the most essential factor because the changes of frequency and heating waveform could result in the changes of temperature essentially.

  8. Time-resolved infrared absorption study of nine TiO2 photocatalysts

    International Nuclear Information System (INIS)

    Yamakata, Akira; Ishibashi, Taka-aki; Onishi, Hiroshi

    2007-01-01

    Electron kinetics of nine TiO 2 catalysts were compared in a microsecond time domain. Each catalyst was band-gap excited with an UV light pulse, and electron-induced absorption of mid infrared light was observed as a function of time delay. The probability of electron-hole recombination in the bulk, electron attachment to adsorbed oxygen, and hole attachment to adsorbed methoxy species was estimated

  9. Fabricating TiO2 nanocolloids by electric spark discharge method at normal temperature and pressure

    Science.gov (United States)

    Tseng, Kuo-Hsiung; Chang, Chaur-Yang; Chung, Meng-Yun; Cheng, Ting-Shou

    2017-11-01

    In this study, TiO2 nanocolloids were successfully fabricated in deionized water without using suspending agents through using the electric spark discharge method at room temperature and under normal atmospheric pressure. This method was exceptional because it did not create nanoparticle dispersion and the produced colloids contained no derivatives. The proposed method requires only traditional electrical discharge machines (EDMs), self-made magnetic stirrers, and Ti wires (purity, 99.99%). The EDM pulse on time (T on) and pulse off time (T off) were respectively set at 50 and 100 μs, 100 and 100 μs, 150 and 100 μs, and 200 and 100 μs to produce four types of TiO2 nanocolloids. Zetasizer analysis of the nanocolloids showed that a decrease in T on increased the suspension stability, but there were no significant correlations between T on and particle size. Colloids produced from the four production configurations showed a minimum particle size between 29.39 and 52.85 nm and a zeta-potential between -51.2 and -46.8 mV, confirming that the method introduced in this study can be used to produce TiO2 nanocolloids with excellent suspension stability. Scanning electron microscopy with energy dispersive spectroscopy also indicated that the TiO2 colloids did not contain elements other than Ti and oxygen.

  10. Fabricating TiO2 nanocolloids by electric spark discharge method at normal temperature and pressure.

    Science.gov (United States)

    Tseng, Kuo-Hsiung; Chang, Chaur-Yang; Chung, Meng-Yun; Cheng, Ting-Shou

    2017-11-17

    In this study, TiO 2 nanocolloids were successfully fabricated in deionized water without using suspending agents through using the electric spark discharge method at room temperature and under normal atmospheric pressure. This method was exceptional because it did not create nanoparticle dispersion and the produced colloids contained no derivatives. The proposed method requires only traditional electrical discharge machines (EDMs), self-made magnetic stirrers, and Ti wires (purity, 99.99%). The EDM pulse on time (T on ) and pulse off time (T off ) were respectively set at 50 and 100 μs, 100 and 100 μs, 150 and 100 μs, and 200 and 100 μs to produce four types of TiO 2 nanocolloids. Zetasizer analysis of the nanocolloids showed that a decrease in T on increased the suspension stability, but there were no significant correlations between T on and particle size. Colloids produced from the four production configurations showed a minimum particle size between 29.39 and 52.85 nm and a zeta-potential between -51.2 and -46.8 mV, confirming that the method introduced in this study can be used to produce TiO 2 nanocolloids with excellent suspension stability. Scanning electron microscopy with energy dispersive spectroscopy also indicated that the TiO 2 colloids did not contain elements other than Ti and oxygen.

  11. GW quasiparticle bandgaps of anatase TiO2 starting from DFT + U.

    Science.gov (United States)

    Patrick, Christopher E; Giustino, Feliciano

    2012-05-23

    We investigate the quasiparticle band structure of anatase TiO(2), a wide gap semiconductor widely employed in photovoltaics and photocatalysis. We obtain GW quasiparticle energies starting from density-functional theory (DFT) calculations including Hubbard U corrections. Using a simple iterative procedure we determine the value of the Hubbard parameter yielding a vanishing quasiparticle correction to the fundamental bandgap of anatase TiO(2). The bandgap (3.3 eV) calculated using this optimal Hubbard parameter is smaller than the value obtained by applying many-body perturbation theory to standard DFT eigenstates and eigenvalues (3.7 eV). We extend our analysis to the rutile polymorph of TiO(2) and reach similar conclusions. Our work highlights the role of the starting non-interacting Hamiltonian in the calculation of GW quasiparticle energies in TiO(2) and suggests an optimal Hubbard parameter for future calculations.

  12. Effect of SiO 2-ZrO 2 supports prepared by a grafting method on hydrogen production by steam reforming of liquefied natural gas over Ni/SiO 2-ZrO 2 catalysts

    Science.gov (United States)

    Seo, Jeong Gil; Youn, Min Hye; Song, In Kyu

    SiO 2-ZrO 2 supports with various zirconium contents are prepared by grafting a zirconium precursor onto the surface of commercial Carbosil silica. Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are then prepared by an impregnation method, and are applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of SiO 2-ZrO 2 supports on the performance of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts is investigated. SiO 2-ZrO 2 prepared by a grafting method serves as an efficient support for the nickel catalyst in the steam reforming of LNG. Zirconia enhances the resistance of silica to steam significantly and increases the interaction between nickel and the support, and furthermore, prevents the growth of nickel oxide species during the calcination process through the formation of a ZrO 2-SiO 2 composite structure. The crystalline structures and catalytic activities of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are strongly influenced by the amount of zirconium grafted. The conversion of LNG and the yield of hydrogen show volcano-shaped curves with respect to zirconium content. Among the catalysts tested, the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) sample shows the best catalytic performance in terms of both LNG conversion and hydrogen yield. The well-developed and pure tetragonal phase of ZrO 2-SiO 2 (Zr/Si = 0.54) appears to play an important role in the adsorption of steam and subsequent spillover of steam from the support to the active nickel. The small particle size of the metallic nickel in the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) catalyst is also responsible for its high performance.

  13. Magnetic and transport properties of Cu1.05Cr0.89 Mg0.05O2 and Cu0.96Cr0.95 Mg0.05Mn0.04O2 films

    International Nuclear Information System (INIS)

    Xu Qingyu; Schmidt, Heidemarie; Zhou Shengqiang; Potzger, Kay; Helm, Manfred; Hochmuth, Holger; Lorenz, Michael; Meinecke, Christoph; Grundmann, Marius

    2008-01-01

    We prepared conductive, polycrystalline or amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 films on a-plane sapphire substrates by pulsed laser deposition under different O 2 partial pressure and substrate temperature. Hall measurements were performed to study the majority carrier type in these films. Polycrystalline Cu 1.05 Cr 0.89 Mg 0.05 O 2 is n-type conducting at 290 K, while in amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 the type of majority charge carriers changes from electrons to holes at around 270 K. Interestingly, the structure has little influence on the magnetic properties of the films. A clear antiferromagnetic to paramagnetic transition was observed in both polycrystalline and amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 films at 25 K. Similar electrical properties to Cu 1.05 Cr 0.89 Mg 0.05 O 2 film were observed for Cu 0.96 Cr 0.95 Mg 0.05 Mn 0.04 O 2 in dependence on the structure, while only paramagnetic without antiferromagnetic ordering was observed down to 5 K. Large negative magnetoresistance of 27% at 20 K was observed at 6 T in amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 film

  14. Toxicity of inhaled 238PuO2 I

    International Nuclear Information System (INIS)

    Diel, J.H.; Mewhinney, J.A.

    1980-01-01

    The deposition, retention, translocation and microscopic distribution of inhaled 238 PuO 2 particles were studied to better define the organs at risk and uniformity of dose and cell types or structures at risk in the lung. Beagle dogs were exposed once by inhalation to an aerosol of 238 PuO 2 with particle aerodynamic diameters of 0.7, 1.4, or 2.7 μm (+-10%). Initial burdens averaged about 700 nCi, a level not expected to induce life-shortening effects in Beagle dogs. Animals were sacrificed at times from 4 hours to 2 years after exposure. Whole body retention of plutonium and its distribution among organs in the sacrificed animals was determined by radiochemical analysis for plutonium content of excreta and tissue samples. The distribution of particles in lung was determined using autoradiographs of lung tissue sections and computer-assisted data collection and analysis. Soon after exposure, PuO 2 was relatively insoluble in lung with individual particles being randomly distributed throughout the lung. A distinct change in the rate of dissolution from lung occurred at about 100 days after exposure resulting in decreased pulmonary retention and increased uptake by liver and skeleton. Particle breakup was observed in autoradiographs for time periods in excess of 128 days after exposure. Broken up particles dissolved rapidly leaving little residue in the lung. The remaining particles were randomly distributed in the lung. These results are discussed in relation to current radiation protection guides for plutonium radionuclides. (author)

  15. Preparation, characterization, and application of Ti/TiO2-NTs/Sb-SnO2 electrode in photo-electrochemical treatment of industrial effluents under mild conditions.

    Science.gov (United States)

    Subba Rao, Anantha N; Venkatarangaiah, Venkatesha T

    2018-04-01

    Ti/TiO 2 -NTs/Sb-SnO 2 electrode was prepared by gradient pulsed electrodeposition, and its electrochemical properties were evaluated. The catalytic activity and reusability of the electrode were tested by electrochemical oxidation (EO) and photoelectrochemical oxidation (PEO) of organics present in textile industry wastewater (TWW) and coffee bean processing industry wastewater (CWW). COD removal of ~ 41% was achieved after 5-h electrolysis under a constant applied current density of 30 mA cm -2 for TWW and 50 mA cm -2 for CWW. Nearly 14 and 18% increment in COD removal was observed under PEO for TWW and CWW, respectively. The turbidity of TWW reduced from 15 to ~ 3 NTU and the turbidity of CWW reduced from 27 to ~ 3 NTU by both EO and PEO. The % COD removal observed after 5-h electrolysis remained consistent for 7 repeated cycles; however, the catalytic activity of the electrode reduced gradually. These results suggested that the Ti/TiO 2 -NTs/Sb-SnO 2 can be a potential electrode for the treatment of industrial wastewater.

  16. Myocardial blood flow and V/sub O2/ in conscious lambs with an aortopulmonary shunt

    International Nuclear Information System (INIS)

    Toorop, G.P.; Hardjowijono, R.; Dalinghaus, M.; Gerding, A.M.; Koers, J.H.; Zijlstra, W.G.; Kuipers, J.R.G.

    1987-01-01

    The authors measured myocardial blood flow (q/sub LVFW/) using radioactively-labeled microspheres and O 2 consumption of the left ventricular free wall (V/sub O 2 , LVFW/) in 13 chronically instrumented, 7-wk-old lambs with an aortopulmonary left-to-right shunt (S) and in 10 control lamps without a shunt (C). The measured V/sub O 2 , LVFW/ was compared with the calculated values obtained by two predictive indexes, the rate-pressure product (RPP) and the pressure-work index (PWI). Measured V/sub O 2 , LVFW/ in S lambs was significantly higher than in C lambs. This was achieved by the significantly higher q/sub LVFW/, since the arteriovenous O 2 difference across the left ventricular free wall was similar in both groups of lambs. Total coronary blood flow per unit body mass in S lambs was higher than in C lambs, not only because of the increased V/sub O 2 , LVFW/ per unit muscle mass, but also because of the increased total heart weight. Correct estimation of V/sub O 2 /, LVFW/ by means of the RPP and the PWI was only possible in C lambs. In S lambs the estimated values were significantly lower than the measured ones. They conclude that since V/sub O 2 , LVFW/ in S lambs is twice as high as in C lambs, the data support the view that a volume load caused by a left-to-right shunt may have a more profound effect on myocardial O 2 consumption than could be anticipated on the basis of previous work

  17. TiO2 and Cu/TiO2 Thin Films Prepared by SPT

    Directory of Open Access Journals (Sweden)

    S. S. Roy

    2015-12-01

    Full Text Available Titanium oxide (TiO2 and copper (Cu doped titanium oxide (Cu/TiO2 thin films have been prepared by spray pyrolysis technique. Titanium chloride (TiCl4 and copper acetate (Cu(CH3COO2.H2O were used as source of Ti and Cu. The doping concentration of Cu was varied from 1-10 wt. %. The X-ray diffraction studies show that TiO2 thin films are tetragonal structure and Cu/TiO2 thin films implies CuO has present with monoclinic structure. The optical properties of the TiO2 thin films have been investigated as a function of Cu-doping level. The optical transmission of the thin films was found to increase from 88 % to 94 % with the addition of Cu up to 8 % and then decreases for higher percentage of Cu doping. The optical band gap (Eg for pure TiO2 thin film is found to be 3.40 eV. Due to Cu doping, the band gap is shifted to lower energies and then increases further with increasing the concentration of Cu. The refractive index of the TiO2 thin films is found to be 2.58 and the variation of refractive index is observed due to Cu doped. The room temperature resistivity of the films decreases with increasing Cu doping and is found to be 27.50 - 23.76 W·cm. It is evident from the present study that the Cu doping promoted the thin film morphology and thereby it is aspect for various applications.

  18. Novel Ag@TiO2 nanocomposite synthesized by electrochemically active biofilm for nonenzymatic hydrogen peroxide sensor.

    Science.gov (United States)

    Khan, Mohammad Mansoob; Ansari, Sajid Ali; Lee, Jintae; Cho, Moo Hwan

    2013-12-01

    A novel nonenzymatic sensor for H2O2 was developed based on an Ag@TiO2 nanocomposite synthesized using a simple and cost effective approach with an electrochemically active biofilm. The optical, structural, morphological and electrochemical properties of the as-prepared Ag@TiO2 nanocomposite were examined by UV-vis spectroscopy, X-ray diffraction, transmission electron microscopy and cyclic voltammetry (CV). The Ag@TiO2 nanocomposite was fabricated on a glassy carbon electrode (GCE) and their electrochemical performance was analyzed by CV, differential pulse voltammetry and electrochemical impedance spectroscopy. The Ag@TiO2 nanocomposite modified GCE (Ag@TiO2/GCE) displayed excellent performance towards H2O2 sensing at -0.73 V in the linear response range from 0.83 μM to 43.3 μM, within a detection limit and sensitivity of 0.83 μM and ~65.2328±0.01 μA μM(-1) cm(-2), respectively. In addition, Ag@TiO2/GCE exhibited good operational reproducibility and long term stability. © 2013.

  19. RHEED study of titanium dioxide with pulsed laser deposition

    DEFF Research Database (Denmark)

    Rasmussen, Inge Lise; Pryds, Nini; Schou, Jørgen

    2009-01-01

    Reflection high-energy electron diffraction (RHEED) operated at high pressure has been used to monitor the growth of thin films of titanium dioxide (TiO2) on (1 0 0) magnesium oxide (MgO) substrates by pulsed laser deposition (PLD). The deposition is performed with a synthetic rutile TiO2 target...

  20. Water Adsorption on TiO2

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Wendt, Stefan; Besenbacher, Flemming

    2010-01-01

    Scanning Tunneling Microscopy (STM) studies and Density Functional Theory (DFT) investigations of the interaction of water with the rutile TiO2 (110) surface are summarized. From high-resolution STM the following reactions have been revealed: water adsorption and diffusion in the Ti troughs, water...... dissociation in bridging oxygen vacancies, assembly of adsorbed water monomers into rapidly diffusing water dimers, and formation of water dimers by reduction of oxygen molecules. The STM results are rationalized based on DFT calculations, revealing the bonding geometries and reaction pathways of the water...

  1. Potentiodynamical deposition of nanostructured MnO2 film at the assist of electrodeposited SiO2 as template

    International Nuclear Information System (INIS)

    Wu, Lian-Kui; Xia, Jie; Hou, Guang-Ya; Cao, Hua-Zhen; Tang, Yi-Ping; Zheng, Guo-Qu

    2016-01-01

    Highlights: • MnO 2 -SiO 2 composite film is prepared by potentiodynamical deposition. • Hierarchical porous MnO 2 films is obtained after the etching of SiO 2 . • The obtained MnO 2 film electrode exhibit high specific capacitance. - Abstract: We report a novel silica co-electrodeposition route to prepare nanostructured MnO 2 films. Firstly, MnO 2 -SiO 2 composite film was fabricated on a stainless steel substrate by potentiodynamical deposition, i.e. cyclic deposition, and then the SiO 2 template was removed by simple immersion in concentrated alkaline solution, leading to the formation of a porous MnO 2 (po-MnO 2 ) matrix. The structure and morphology of the obtained films were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties of the po-MnO 2 film were evaluated by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS). Results showed that this porous MnO 2 derived from the MnO 2 -SiO 2 composite film exhibits good electrochemical performance for potential use as a supercapacitor material.

  2. Synthesis of TiO(2)-PMMA nanocomposite: using methacrylic acid as a coupling agent.

    Science.gov (United States)

    Khaled, S M; Sui, Ruohong; Charpentier, Paul A; Rizkalla, Amin S

    2007-03-27

    Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Methacrylic acid (MA), a functionalization agent that can chemically link TiO2 nanomaterials (n-TiO2) and polymer matrix, was used to modify the surface of n-TiO2 using a Ti-carboxylic coordination bond. Then, the double bond in MA was copolymerized with methyl methacrylate (MMA) to form a n-TiO2-PMMA nanocomposite. The resulting n-TiO2-PMMA nanocomposite materials were characterized by using thermal analysis, electron microscopy, and elemental analysis. The dynamic mechanical properties (Young's and shear modulus) were measured using an ultrasonic pulse technique. The electron microscopy results showed a good distribution of the nanofillers in the polymer matrix. The glass transition temperature, thermal degradation temperature, and dynamic elastic moduli of the nanocomposites were shown to increase with an increase in the weight percentage of nanofibers in the composite. The resulting nanocomposites exhibited improved elastic properties and have potential application in dental composites and bone cements.

  3. Experimental and clinical evaluation of a noninvasive reflectance pulse oximeter sensor.

    Science.gov (United States)

    Takatani, S; Davies, C; Sakakibara, N; Zurick, A; Kraenzler, E; Golding, L R; Noon, G P; Nose, Y; DeBakey, M E

    1992-10-01

    The objective of this study was to evaluate a new reflectance pulse oximeter sensor. The prototype sensor consists of 8 light-emitting diode (LED) chips (4 at 665 nm and 4 at 820 nm) and a photodiode chip mounted on a single substrate. The 4 LED chips for each wavelength are spaced at 90-degree intervals around the substrate and at an equal radial distance from the photodiode chip. An optical barrier between the photodiode and LED chips prevents a direct coupling effect between them. Near-infrared LEDs (940 nm) in the sensor warm the tissue. The microthermocouple mounted on the sensor surface measures the temperature of the skin-sensor interface and maintains it at a present level by servoregulating the current in the 940-nm LEDs. An animal study and a clinical study were performed. In the animal study, 5 mongrel dogs (weight, 10-20 kg) were anesthetized, mechanically ventilated, and cannulated. In each animal, arterial oxygen saturation (SaO2) was measured continuously by a standard transmission oximeter probe placed on the dog's earlobe and a reflectance oximeter sensor placed on the dog's tongue. In the first phase of the experiment, signals from the reflectance sensor were recorded while the dog was immersed in ice water until its body temperature decreased to 30 degrees C. In the second phase, the animal's body temperature was normal, and the oxygen content of the ventilator was varied to alter the SaO2. In the clinical study, 18 critically ill patients were monitored perioperatively with the prototype reflectance sensor. The first phase of the study investigated the relationship between local skin temperature and the accuracy of oximeter readings with the reflectance sensor. Each measurement was taken at a high saturation level as a function of local skin temperature. The second phase of the study compared measurements of oxygen saturation by a reflectance oximeter (SpO2[r]) with those made by a co-oximeter (SaO2[IL]) and a standard transmission oximeter (SpO

  4. Catalytic recombination of dissociation products with Pt/SnO2 for rare and common isotope long-life, closed-cycle CO2 lasers

    Science.gov (United States)

    Brown, Kenneth G.; Sidney, B. D.; Schryer, D. R.; Upchurch, B. T.; Miller, I. M.

    1986-01-01

    This paper reports results on recombination of pulsed CO2 laser dissociation products with Pt/SnO2 catalysts, and supporting studies in a surrogate laboratory catalyst reactor. The closed-cycle, pulsed CO2 laser has been continuously operated for one million pulses with an overall power degradation of less than 5 percent by flowing the laser gas mixture through a 2-percent Pt/SnO2 catalyst bed. In the surrogate laboratory reactor, experiments have been conducted to determine isotopic exchange with the catalyst when using rare-isotope gases. The effects of catalyst pretreatment, sample weight, composition, and temperature on catalyst efficiency have also been determined.

  5. TiO2-TiO2 composite resistive humidity sensor: ethanol crosssensitivity

    International Nuclear Information System (INIS)

    Ghalamboran, Milad; Saedi, Yasin

    2016-01-01

    The fabrication method and characterization results of a TiO 2 -TiO 2 composite bead used for humidity sensing along with its negative cross-sensitivity to ethanol vapor are reported. The bead shaped resistive sample sensors are fabricated by the drop-casting of a TiO 2 slurry on two Pt wire segments. The dried bead is pre-fired at 750°C and subsequently impregnated with a Ti-based sol. The sample is ready for characterization after a thermal annealing at 600°C in air. Structurally, the bead is a composite of the micron-sized TiO 2 crystallites embedded in a matrix of nanometric TiO 2 particle aggregates. The performance of the beads as resistive humidity sensors is recorded at room temperature in standard humidity level chambers. Results evince the wide dynamic range of the sensors fabricated in the low relative humidity range. While the sensor conductance is not sensitive to ethanol vapor in dry air, in humid air, sensor's responses are negatively affected by the contaminant. (paper)

  6. Time-resolved pH/pO2 mapping with luminescent hybrid sensors.

    Science.gov (United States)

    Schröder, Claudia R; Polerecky, Lubos; Klimant, Ingo

    2007-01-01

    A method for simultaneous and referenced 2D mapping of pH and pO2 is described. The experimental setup combines a fast gateable CCD camera as detector, a LED as excitation light source and a single-layer sensor membrane as optical transducer. The planar optode comprises a lipophilic fluorescein derivative (lifetime approximately 5 ns) and platinum(II) mesotetrakis(pentafluorophenyl)porphyrin (approximately 70 micros in the absence of a quencher) immobilized in a hydrogel matrix. Depending on the fluorescent pH indicator, a pH transition in the physiological range (pH 6-pH 8) or in the near-basic region (pH 7-pH 9) can be achieved. The measuring scheme involves the time-resolved acquisition of images in three windows during a series of square-shaped excitation pulses. A method allowing the calculation of both parameters from these three images is presented. The pH/pO2 hybrid sensor incorporating the pH indicator 2',7'-dihexyl-5(6)-N-octadecyl-carboxamidofluorescein was characterized in detail. The pH and pO2 were determined with a maximum deviation of 0.03 pH unit and 6.5 hPa pO2, respectively, within the range of pH 7.6-pH 8.7 and 0-200 hPa pO2 in test measurements. The ionic strength (IS) cross-sensitivity was found to be relatively small (pH/IS pO2/IS pO2 images obtained in natural marine sediment are presented.

  7. Characterization and Comparison of Photocatalytic Activity Silver Ion doped on TiO2(TiO2/Ag+) and Silver Ion doped on Black TiO2(Black TiO2/Ag+)

    Science.gov (United States)

    Kim, Jin Yi; Sim, Ho Hyung; Song, Sinae; Noh, Yeoung Ah; Lee, Hong Woon; Taik Kim, Hee

    2018-03-01

    Titanium dioxide (TiO2) is one of the representative ceramic materials containing photocatalyst, optic and antibacterial activity. The hydroxyl radical in TiO2 applies to the intensive oxidizing agent, hence TiO2 is suitable to use photocatalytic materials. Black TiO2was prepared through reduction of amorphous TiO2 conducting under H2 which leads to color changes. Its black color is proven that absorbs 100% light across the whole-visible light, drawing enhancement of photocatalytic property. In this study, we aimed to compare the photocatalytic activity of silver ion doped on TiO2(TiO2/Ag+) and silver ion doped on black TiO2(black TiO2/Ag+) under visible light range. TiO2/Ag+ was fabricated following steps. 1) TiO2 was synthesized by a sol-gel method from Titanium tetraisopropoxide (TTIP). 2) Then AgNO3 was added during an aging process step for silver ion doping on the surface of TiO2. Moreover, Black TiO2/Ag+ was obtained same as TiO2/Ag+ except for calcination under H2. The samples were characterized X-ray diffraction (XRD), UV-visible reflectance (UV-vis DRS), and Methylene Blue degradation test. XRD analysis confirmed morphology of TiO2. The band gap of black TiO2/Ag+ was confirmed (2.6 eV) through UV-vis DRS, which was lower than TiO2/Ag+ (2.9 eV). The photocatalytic effect was conducted by methylene blue degradation test. It demonstrated that black TiO2/Ag+ had a photocatalytic effect under UV light also visible light.

  8. Effect of processing conditions and methods on residual stress in CeO2 buffer layers and YBCO superconducting films

    International Nuclear Information System (INIS)

    Xiong Jie; Qin Wenfeng; Cui Xumei; Tao Bowan; Tang Jinlong; Li Yanrong

    2006-01-01

    CeO 2 layers have been fabricated by pulsed laser deposition (PLD) technique on (1 1 0 2) sapphire substrate. Microstructure of CeO 2 layers is characterized by X-ray diffraction as functions of substrate temperature. The effects of the substrate temperature on the residual stress have been studied. The results show that residual stress in CeO 2 film decreased with increasing substrate temperature, not the same development tendency as that of thermal stress. This means that the thermal stress is only a fraction of the residual stress. Moreover, YBCO superconducting films were prepared by direct current (DC) sputtering and pulsed laser deposition (PLD) technique. The residual stress and thermal stress of both YBCO films were measured. PLD processing apparently generated higher intrinsic compressive stresses in comparison to DC sputtering

  9. Spectroscopic and neutron detection properties of rare earth and titanium doped LiAlO 2 single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Dickens, Peter T.; Marcial, José; McCloy, John; McDonald, Benjamin S.; Lynn, Kelvin G.

    2017-10-01

    In this study, LiAlO2 crystals doped with rare-earth elements and Ti were produced by the CZ method and spectroscopic and neutron detection properties were investigated. Photoluminescence revealed no clear luminescent activation of LiAlO2 by the rare-earth dopants though some interesting luminescence was observed from secondary phases within the crystal. Gamma-ray pulse height spectra collected using a 137Cs source exhibited only a Compton edge for the crystals. Neutron modeling using Monte Carlo N-Particle Transport Code revealed most neutrons used in the detection setup are thermalized, and while using natural lithium in the crystal growth, which contains 7.6 % 6Li, a 10 mm Ø by 10 mm sample of LiAlO2 has a 70.7 % intrinsic thermal neutron capture efficiency. Furthermore, the pulse height spectra collected using a 241Am-Be neutron source demonstrated a distinct neutron peak.

  10. Evaluation of hemodynamic and SpO2 variability during different stages of periodontal surgery

    Directory of Open Access Journals (Sweden)

    Babak Amoian

    2013-01-01

    Full Text Available Background: Changes in pulse rate and blood pressure are common consequences during oral surgeries. Hypoxia during surgical process is another side effect. The objective of the present study was evaluation of blood hemoglobin oxygenation and hemodynamic changes during periodontal surgery. Materials and Methods: This clinical trial study was conducted upon 50 subjects aged 30-55 years who referred to the clinic of dental faculty of Babol University and needed periodontal surgery with modified widman flaps in the anterior section of the maxilla. Pulse rate, blood pressure, and pulse oximetric evaluations were recorded in five stages during surgery. Results: The average of systolic and diastolic blood pressure had been in their maximum amount in the second stage of evaluation and minimum amounts were in the first one; while pulse rate changes were greatest in the second stage and lowest in the fifth stage. Analyzing the data revealed no significant difference in Blood Oxygen Saturation (SpO2 measurements in none of the stages evaluated. Conclusions: Blood pressure and heart rate increased significantly after the injection of anesthetic drug and in further phases they were decreased after the elimination of stimulating effect of adrenaline. SpO 2 changes were not significantly prominent.

  11. Preparation and solar-light photocatalytic activity of TiO2 composites: TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite

    Science.gov (United States)

    Li, Y.; Li, S. G.; Wang, J.; Li, Y.; Ma, C. H.; Zhang, L.

    2014-12-01

    Three TiO2 loaded composites, TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite, were prepared in order to improve the solar-light photocatalytic activity of TiO2. The results showed that the photocatalytic activity could obviously be enhanced by loading appropriate amount of inorganic mineral materials. Meanwhile, TiO2 content, heat-treatment temperature and heat-treatment time on the photocatalytic activity were reviewed. Otherwise, the effect of solar light irradiation time and dye concentration on the photocatalytic degradation of Acid Red B was investigated. Furthermore, the degradation mechanism and adsorption process were also discussed.

  12. Incorporation of sol-gel SnO2:Sb into nanoporous SiO2

    International Nuclear Information System (INIS)

    Canut, B.; Blanchin, M.G.; Ramos-Canut, S.; Teodorescu, V.; Toulemonde, M.

    2006-01-01

    Silicon oxide films thermally grown on Si(1 0 0) wafers were irradiated with 200 MeV 197 Au ions in the 10 9 -10 1 cm -2 fluence range. The targets were then etched at room temperature in aqueous HF solution (1 vol.%) for various durations. Atomic force microscopy (AFM) in the tapping mode was used to probe the processed surfaces. Conical holes with a low size dispersion were evidenced. Their surface diameter varies between 20 and 70 nm, depending on the etching time. Sol-gel dip coating technique, associated with a further annealing treatment performed at 500 o C for 15 min, was used to fill the nanopores created in SiO 2 with a transparent conductive oxide (SnO 2 doped with antimony). Transmission electron microscopy (TEM) performed on cross-sectional specimen showed that SnO 2 :Sb crystallites of ∼5 nm mean size are trapped in the holes without degrading their geometry

  13. On the rutile alpha-PbO"2-type phase boundary of TiO"2

    DEFF Research Database (Denmark)

    Olsen, J.S.; Gerward, Leif; Jiang, Jianzhong

    1999-01-01

    The high-pressure, high-temperature phase quilibria of TiO"2 have been studied with special emphasis on the rutile and alpha-PbO"2-type phases. It is found that the phase boundary, when plotted in a pressure-temperature diagram, changes from having a negative to having a positive slope...... with increasing temperature at about 6GPa and 850^oC. For nanophase material, the phase boundary is shifted towards lower pressure. The room-temperature bulk moduli are 210(120)GPa, 258(8)GPa and 290(20)GPa for rutile, the alpha-PbO"2-type phase and the baddeleyite-type phase, respectively....

  14. Nonohmic behavior of SnO2.MnO2-based ceramics

    Directory of Open Access Journals (Sweden)

    Marcelo O. Orlandi

    2003-06-01

    Full Text Available The present paper describes the nonohmic behavior of the SnO2.MnO-based system and analyzes the influence of the sintering time and the Nb2O5 concentration on this system's electrical properties. A nonlinear coefficient of ~7 was obtained for a 0.2 mol%-doped Nb2O5 composition, which is comparable to other values reported in the literature for the ternary SnO2-based systems. A recent barrier formation model proposed in the literature to explain the nonlinear electrical behavior of SnO2-based systems is used to clarify the role of the MnO constituent in the formation of the barrier, taking into account the influence of segregated atoms, precipitated phase and oxygen species in the grain boundary region.

  15. Late effects of inhaled 238PuO2 in beagles

    International Nuclear Information System (INIS)

    Park, J.F.; Case, A.C.; Catt, D.L.; Hackett, P.L.; Lund, J.E.; Powers, G.J.; Ragan, H.A.; Watson, C.R.

    1976-01-01

    Osteosarcomas were the primary cause of death in beagle dogs 4 to 8 years after inhalation of 238 PuO 2 . The plutonium body burden at death ranged from 0.4 to 2.6 μCi with 32 to 55 percent of the plutonium in the skeleton. Pulmonary neoplasia was observed in three of the bone-tumor-bearing dogs

  16. Characteristics of RuO2-SnO2 nanocrystalline-embedded amorphous electrode for thin film microsupercapacitors

    International Nuclear Information System (INIS)

    Kim, Han-Ki; Choi, Sun-Hee; Yoon, Young Soo; Chang, Sung-Yong; Ok, Young-Woo; Seong, Tae-Yeon

    2005-01-01

    The characteristics of RuO 2 -SnO 2 nanocrystalline-embedded amorphous electrode, grown by DC reactive sputtering, was investigated. X-ray diffraction (XRD), transmission electron microscopy (TEM), and transmission electron diffraction (TED) examination results showed that Sn and Ru metal cosputtered electrode in O 2 /Ar ambient have RuO 2 -SnO 2 nanocrystallines in an amorphous oxide matrix. It is shown that the cyclic voltammorgram (CV) result of the RuO 2 -SnO 2 nanocrystalline-embedded amorphous film in 0.5 M H 2 SO 4 liquid electrolyte is similar to a bulk-type supercapacitor behavior with a specific capacitance of 62.2 mF/cm 2 μm. This suggests that the RuO 2 -SnO 2 nanocrystalline-embedded amorphous film can be employed in hybrid all-solid state energy storage devises as an electrode of supercapacitor

  17. Influence of exercise intensity on skeletal muscle blood flow, O2 extraction and O2 uptake on-kinetics

    DEFF Research Database (Denmark)

    Jones, Andrew M; Krustrup, Peter; Wilkerson, Daryl P

    2012-01-01

    Key points Following the start of low-intensity exercise in healthy humans, it has been established that the kinetics of muscle O(2) delivery is faster than, and does not limit, the kinetics of muscle O(2) uptake. Direct data are lacking, however, on the question of whether O(2) delivery might...... limit O(2) uptake kinetics during high-intensity exercise. In this study, we made frequent measurements of muscle blood flow, arterial-to-venous O(2) difference (a- difference) and O(2) uptake following the onset of multiple transitions of both low-intensity and high-intensity knee-extension exercise...... in the same subjects. We show that although blood flow kinetics is slower for high-intensity compared with low-intensity exercise, this does not result in slower O(2) uptake kinetics. These results indicate that muscle O(2) delivery does not limit O(2) uptake during knee-extension exercise in healthy humans....

  18. Atomistic growth phenomena of reactively sputtered RuO2 and MnO2 thin films

    International Nuclear Information System (INIS)

    Music, Denis; Bliem, Pascal; Geyer, Richard W.; Schneider, Jochen M.

    2015-01-01

    We have synthesized RuO 2 and MnO 2 thin films under identical growth conditions using reactive DC sputtering. Strikingly different morphologies, namely, the formation of RuO 2 nanorods and faceted, nanocrystalline MnO 2 , are observed. To identify the underlying mechanisms, we have carried out density functional theory based molecular dynamics simulations of the growth of one monolayer. Ru and O 2 molecules are preferentially adsorbed at their respective RuO 2 ideal surface sites. This is consistent with the close to defect free growth observed experimentally. In contrast, Mn penetrates the MnO 2 surface reaching the third subsurface layer and remains at this deep interstitial site 3.10 Å below the pristine surface, resulting in atomic scale decomposition of MnO 2 . Due to this atomic scale decomposition, MnO 2 may have to be renucleated during growth, which is consistent with experiments

  19. Improved conversion efficiency of dye sensitized solar cell using Zn doped TiO_2-ZrO_2 nanocomposite

    International Nuclear Information System (INIS)

    Tomar, Laxmi J.; Bhatt, Piyush J.; Desai, Rahul K.; Chakrabarty, B. S.; Panchal, C. J.

    2016-01-01

    TiO_2-ZrO_2 and Zn doped TiO_2-ZrO_2 nanocomposites were prepared by hydrothermal method for dye sensitized solar cell (DSSC) application. The structural and optical properties were investigated by X –ray diffraction (XRD) and UV-Visible spectroscopy respectively. XRD results revealed the formation of material in nano size. The average crystallite size is 22.32 nm, 17.41 nm and 6.31 nm for TiO_2, TiO_2-ZrO_2 and Zn doped TiO_2-ZrO_2 nanocomposites respectively. The optical bandgap varies from 2.04 eV to 3.75 eV. Dye sensitized solar cells were fabricated using the prepared material. Pomegranate juice was used as a sensitizer and graphite coated conducting glass plate was used as counter electrode. The I – V characteristics were recorded to measure photo response of DSSC. Photovoltaic parameter like open circuit voltage, power conversion efficiency, and fill factor were evaluated for fabricated solar cell. The power conversion efficiency of DSSC fabricated with TiO_2, TiO_2-ZrO_2 and Zn doped TiO_2-ZrO_2 nanocomposites were found 0.71%, 1.97% and 4.58% respectively.

  20. Morphologically controlled synthesis, structural and optical properties of CeO2/SnO2 nanocomposites

    Directory of Open Access Journals (Sweden)

    S. Usharani

    2017-09-01

    Full Text Available CeO2/SnO2 nanocomposites with different dimensional nanostructures were synthesized by a wet chemical method, using various surfactants such as SDS, CTAB and Triton X-100. The prepared CeO2/SnO2 samples were analyzed by X-ray diffraction (XRD, Fourier transform infrared (FTIR, Transmission electron microscopy (TEM, UV-Diffuse Reflectance Spectroscopy (UV-DRS, and Photoluminescence (PL spectroscopy. The XRD patterns reveal the presence of a mixed phase of SnO2 and CeO2; The TEM analysis showed the mixed morphology of uniformly dispersed spherical with ellipsoidal shape in the SDS assisted CeO2/SnO2 nanocomposites; whereas the nanostructure with spherical with hexagonal shapes was observed for the Triton X-100 assisted CeO2/SnO2 nanocomposites. The one dimensional (1D nanorod like structure observed for the CTAB assisted CeO2/SnO2 nanocomposites shows CTAB acting as a face-specific capping agent to form rod-shaped micelles. The room temperature photoluminescence emission studies of the CeO2/SnO2 nanocomposites showed strong peaks in the UV region, and several peaks in the visible region, which are likely to have originated from the oxygen vacancies and are potential materials for optoelectronic device applications. The UV results showed the absorption edges shifted to a high energy region and the blue shifts that occurred in all the samples.

  1. Improved conversion efficiency of dye sensitized solar cell using Zn doped TiO2-ZrO2 nanocomposite

    Science.gov (United States)

    Tomar, Laxmi J.; Bhatt, Piyush J.; Desai, Rahul K.; Chakrabarty, B. S.; Panchal, C. J.

    2016-05-01

    TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites were prepared by hydrothermal method for dye sensitized solar cell (DSSC) application. The structural and optical properties were investigated by X -ray diffraction (XRD) and UV-Visible spectroscopy respectively. XRD results revealed the formation of material in nano size. The average crystallite size is 22.32 nm, 17.41 nm and 6.31 nm for TiO2, TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites respectively. The optical bandgap varies from 2.04 eV to 3.75 eV. Dye sensitized solar cells were fabricated using the prepared material. Pomegranate juice was used as a sensitizer and graphite coated conducting glass plate was used as counter electrode. The I - V characteristics were recorded to measure photo response of DSSC. Photovoltaic parameter like open circuit voltage, power conversion efficiency, and fill factor were evaluated for fabricated solar cell. The power conversion efficiency of DSSC fabricated with TiO2, TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites were found 0.71%, 1.97% and 4.58% respectively.

  2. Eletroxidação do etanol em eletrodos de Ti/IrO2 Electro-oxidation of ethanol in Ti/IrO2

    Directory of Open Access Journals (Sweden)

    Carlos H.V. Fidelis

    2001-02-01

    Full Text Available It has been carried out an investigation of ethanol electro-oxidation on Ti/IrO2 electrodes. The experimental results show a high selectivity towards acetaldehyde formation thus, offering potential advantages in cost and availability of raw material. It has been observed that the electrode is partially blocked by a film formed after the oxidation of the starting material which can be removed by pulse technique between RDO and RDH onset. The mechanism and the selectivity of the product formed is presented.

  3. Direct reduction of 238PuO2 and 239PuO2 to metal

    International Nuclear Information System (INIS)

    Mullins, L.J.; Foxx, C.L.

    1982-02-01

    The process for reducing 700 g 239 PuO 2 to metal is a standard procedure at Los Alamos National Laboratory. This process is based on research for reducing 200 g 238 PuO 2 to metal. This report describes in detail the experiments and development of the 200-g process. The procedure uses calcium metal as the reducing agent in a molten CaCl 2 solvent system. The process to convert impure plutonia to high-purity metal by oxide reduction followed by electrorefining is also described

  4. Friction and wear properties of ZrO2/SiO2 composite nanoparticles

    International Nuclear Information System (INIS)

    Li Wei; Zheng Shaohua; Cao Bingqiang; Ma Shiyu

    2011-01-01

    In this article, the lubrication properties of ZrO 2 /SiO 2 composite nanoparticles modified with aluminum zirconium coupling agent as additives in lubricating oil under variable applied load and concentration fraction were reported. It was demonstrated that the modified nanoparticles as additives in lubrication can effectively improve the lubricating properties. Under an optimized concentration of 0.1 wt%, the average friction coefficient was reduced by 16.24%. This was because the nanoparticles go into the friction zone with the flow of lubricant, and then the sliding friction changed to rolling friction with a result of the reduction of the friction coefficient.

  5. Internal Friction of (SiO2)1-x (GeO2)x Glasses

    OpenAIRE

    Kosugi , T.; Kobayashi , H.; Kogure , Y.

    1996-01-01

    Internal friction of (SiO2)1-x (GeO2)x glasses (x = 0, 5, 10, 24 and 100 mole%) is measured at temperatures between 1.6 and 280 K. The data are filted with the equations for thermally activated relaxation with distributing activation energies in symmetrical double-well potentials. From the determined relaxation strength spectra for each sample, the contributions from each type of microscopic structural units are calculated assuming that transverse motion of the bridging O atom in Si-O-Si, Si-...

  6. A comparative study of the magnetization in transition metal ion doped CeO2, TiO2 and SnO2 nanoparticles

    Science.gov (United States)

    Apostolov, A. T.; Apostolova, I. N.; Wesselinowa, J. M.

    2018-05-01

    Using the microscopic s-d model taking into account anharmonic spin-phonon interactions we have studied the magnetic properties of Co and Cu ion doped CeO2 and TiO2 nanoparticles and compared them with those of SnO2. By Co-doping there is a maximum in the magnetization M(x) curve for all nanoparticles observed in the most transition metal doped ones. The s-d interaction plays an important role by the decrease of M at higher dopant concentration. We have discussed the magnetization in dependence of different model parameters. By small Cu-ion doping there are some differences. In CeO2M decreases with the Cu-concentration, whereas in TiO2 and SnO2M increases. For higher Cu dopant concentrations M(X) decreases in TiO2 nanoparticles. We obtain room temperature ferromagnetism also in Zn doped CeO2, TiO2 and SnO2 nanoparticles, i.e. in non-transition metal ion doped ones. The different behavior of M in Co and Cu doped nanoparticles is due to a combination effect of multivalent metal ions, oxygen vacancies, different radius of cation dopants, connection between lattice and magnetism, as well as competition between the s-d and d-d ferromagnetic or antiferromagnetic interactions.

  7. TiO2/Pt/TiO2 Sandwich Nanostructures: Towards Alcohol Sensing and UV Irradiation-Assisted Recovery

    Directory of Open Access Journals (Sweden)

    Rungroj Maolanon

    2017-01-01

    Full Text Available The TiO2/Pt/TiO2 sandwich nanostructures were synthesized by RF magnetron sputtering and demonstrated as an alcohol sensor at room-temperature operation with a fast recovery by UV irradiation. The TiO2/Pt/TiO2 layers on SiO2/Si substrate were confirmed by Auger electron spectroscopy with the interdiffusion of each layer. The TiO2/Pt/TiO2 layers on printed circuit board show the superior sensor response to alcohol in terms of the sensitivity and stability compared to the nonsandwich structure, that is, the only Pt layer or the TiO2/Pt structures. Moreover, the recovery time of the TiO2/Pt/TiO2 was improved by UV irradiation-assisted recovery. The optimum TiO2/Pt/TiO2 with thicknesses of the undermost TiO2 layer, a Pt layer, and the topmost TiO2 layer being 50 nm, 6 nm, and 5 nm, respectively, showed the highest response to ethanol down to 10 ppm. Additionally, TiO2/Pt/TiO2 shows an excellent sensing stability and exhibits different sensing selectivity among ethanol, methanol, and 2-propanol. The sensing mechanism could be attributed to the change of Pt work function during vapor adsorption. The TiO2 layer plays an important role in UV-assisted recovery by photocatalytic activity and the topmost TiO2 acts as protective layer for Pt.

  8. Water on Graphene-Coated TiO2: Role of Atomic Vacancies

    Science.gov (United States)

    2018-01-01

    Beyond two-dimensional (2D) materials, interfaces between 2D materials and underlying supports or 2D-coated metal or metal oxide nanoparticles exhibit excellent properties and promising applications. The hybrid interface between graphene and anatase TiO2 shows great importance in photocatalytic, catalytic, and nanomedical applications due to the excellent and complementary properties of the two materials. Water, as a ubiquitous and essential element in practical conditions and in the human body, plays a significant role in the applications of graphene/TiO2 composites for both electronic devices and nanomedicine. Carbon vacancies, as common defects in chemically prepared graphene, also need to be considered for the application of graphene-based materials. Therefore, the behavior of water on top and at the interface of defective graphene on anatase TiO2 surface was systematically investigated by dispersion-corrected hybrid density functional calculations. The presence of the substrate only slightly enhances the on-top adsorption and reduces the on-top dissociation of water on defective graphene. However, at the interface, dissociated water is largely preferred compared with undissociated water on bare TiO2 surface, showing a prominent cover effect. Reduced TiO2 may further induce oxygen diffusion into the bulk. Our results are helpful to understand how the presence of water in the surrounding environment affects structural and electronic properties of the graphene/TiO2 interface and thus its application in photocatalysis, electronic devices, and nanomedicine. PMID:29368503

  9. Ultra-fine structural characterization and bioactivity evaluation of TiO2 nanotube layers.

    Science.gov (United States)

    Jang, JaeMyung; Kwon, TaeYub; Kim, KyoHan

    2008-10-01

    For an application as biomedical materials of high performance with a good biocompatibility, the TiO2 nanotube-type oxide film on Ti substrate has been fabricated by electrochemical method, and the effects of surface characteristics of TiO2 naotube layer have been investigated. The surface morphology of TiO2 nanotube layer depends on factors such as anodizing time, current density, and electrolyte temperature. Moreover, the cell and pore size gradually were increased with the passage of anodizing time. X-ray diffraction (XRD) results indicated that the TiO2 nanotube layer formed in acidic electrolytes was mainly composed of anatase structure containing rutile. From the analysis of chemical states of TiO2 nanotube layer using X-ray photoelectron spectroscopy (XPS), Ti2p, P2p and O1s were observed in the nanotubes layer, which were penetrated from the electrolyte into the oxide layer during anodic process. The incorporated phosphate species were found mostly in the forms of HPO4-, PO4-, and PO3-. From the result of biological evaluation in simulated body fluid (SBF) the TiO2 nanotube layer was effective for bioactive property.

  10. Isometric strength training lowers the O2 cost of cycling during moderate-intensity exercise.

    Science.gov (United States)

    Zoladz, Jerzy A; Szkutnik, Zbigniew; Majerczak, Joanna; Grandys, Marcin; Duda, Krzysztof; Grassi, Bruno

    2012-12-01

    The effect of maximal voluntary isometric strength training of knee extensor muscles on pulmonary V'O(2) on-kinetics, the O(2) cost of cycling and peak oxygen uptake (V'O(2peak)) in humans was studied. Seven healthy males (mean ± SD, age 22.3 ± 2.0 years, body weight 75.0 ± 9.2 kg, V'O(2peak) 49.5 ± 3.8 ml kg(-1) min(-1)) performed maximal isometric strength training lasting 7 weeks (4 sessions per week). Force during maximal voluntary contraction (MVC) increased by 15 % (P Strength training resulted in a significant decrease (by ~7 %; P Isometric strength training rapidly (i.e., after 1 week) decreases the O(2) cost of cycling during moderate-intensity exercise, whereas it does not affect the amplitude of the slow component of the V'O(2) on-kinetics during heavy-intensity exercise. Isometric strength training can have beneficial effects on performance during endurance events.

  11. Growth of TiO2-ZrO2 Binary Oxide Electrode for Dye Sensitized Solar Cell Application

    International Nuclear Information System (INIS)

    Than Than Win; Aye Myint Myat Kywe; Shwe Yee Win; Honey Thaw; Yin Maung Maung; Ko Ko Kyaw Soe

    2011-12-01

    TiO2-ZrO2 fine binary oxide was prepared by mechanochemical milling process to be homogeneous binary oxide powder. TiO2-ZrO2 paste was deposited on microscopic glass slide by rolling. It was immersed in the henna solution and annealed at 100C for 2h. It was deposited onto another glass slide and used as counter electrode (second electrode). Two glass slides were offset and two binder clips were used to hold the electrodes together. Photovoltaic properties of TiO2-ZrO2 cell were measured and it was expected to utilize the dye sensitized solar cells application.

  12. Chirped pulse amplification: Present and future

    International Nuclear Information System (INIS)

    Maine, P.; Strickland, D.; Pessot, M.; Squier, J.; Bado, P.; Mourou, G.; Harter, D.

    1988-01-01

    Short pulses with ultrahigh peak powers have been generated in Nd: glass and Alexandrite using the Chirped Pulse Amplification (CPA) technique. This technique has been successful in producing picosecond terawatt pulses with a table-top laser system. In the near future, CPA will be applied to large laser systems such as NOVA to produce petawatt pulses (1 kJ in a 1 ps pulse) with focused intensities exceeding 10/sup /plus/21/ W/cm 2 . These pulses will be associated with electric fields in excess of 100 e/a/sub o/ 2 and blackbody energy densities equivalent to 3 /times/ 10 10 J/cm 3 . This petawatt source will have important applications in x-ray laser research and will lead to fundamentally new experiments in atomic, nuclear, solid-state, plasma, and high-energy density physics. A review of present and future designs are discussed. 17 refs., 5 figs

  13. Effects of cord compression on fetal blood flow distribution and O2 delivery

    International Nuclear Information System (INIS)

    Itskovitz, J.; LaGamma, E.F.; Rudolph, A.M.

    1987-01-01

    The authors used the radionuclide microsphere technique in nine fetal lambs to examine the effect of partial cord compression on distribution of cardiac output and O 2 delivery to fetal organs and venous flow patterns. With a 50% reduction in umbilical blood flow the fraction of fetal cardiac output distributed to the brain, heart, carcass, kidneys, and gastrointestinal tract increased. Pulmonary blood flow fell. O 2 delivery to the brain and myocardium was maintained but was reduced to peripheral, renal, and gastrointestinal circulations. Hepatic blood flow decreased and O 2 delivery fell by 75%. The proportion of umbilical venous blood passing through the ductus venosus increased from 43.9 to 71.8%. The preferential distribution of ductus venosus blood flow through the foramen ovale was enhanced and the proportion of O 2 delivery to upper body organs derived from the ductus venosus increased. Abdominal inferior vena caval blood flow increased, and it was also preferentially distributed through the foramen ovale and constituted the major fraction of the arterial blood supply to the upper body organs. Thus cord compression modified the distribution of cardiac output and the patterns of venous returns in the fetus. This pattern of circulatory response differs from that observed with other causes of reduced O 2 delivery

  14. Numerical investigation of drag and heat flux reduction mechanism of the pulsed counterflowing jet on a blunt body in supersonic flows

    Science.gov (United States)

    Zhang, Rui-rui; Huang, Wei; Yan, Li; Li, Lang-quan; Li, Shi-bin; Moradi, R.

    2018-05-01

    To design a kind of aerospace vehicle, the drag and heat flux reduction are the most important factors. In the current study, the counterflowing jet, one of the effective drag and heat flux reduction concepts, is investigated numerically by the two-dimensional axisymmetric Reynolds-averaged Navier-Stokes equations coupled with the SST k-ω turbulence model. An axisymmetric numerical simulation mode of the counterflowing jet on the supersonic vehicle nose-tip is established, and the numerical method employed is validated by the experimental schlieren images and experimental data in the open literature. A pulsed counterflowing jet scheme is proposed, and it uses a sinusoidal function to control the total and static pressures of the counterflowing jet. The obtained results show that the long penetration mode does not exist in the whole turnaround, even in a relatively small range of the jet total and static pressures, and this is different from the phenomenon obtained under the steady condition in the open literature. At the same time, it is observed that the variation of the physical parameters, such as the Stanton number induced by the pulsed jet, has an obvious periodicity and hysteresis phenomenon.

  15. Thermal Degradation of Nanocomposited PMMA/TiO2 Nanocomposites

    International Nuclear Information System (INIS)

    Hafizah, Nik Noor; Mamat, Mohamad Hafiz; Rusop, Mohamad; Said, Che Mohamad Som; Abidin, Mohd Hanafiah

    2013-01-01

    The polymer nanocomposite is a new choice to conventionally filled polymers. The lack of proper binding between the filler and the polymer can lead the decrease of the thermal and other properties of the nanocomposites. In this study, the nanocomposited PMMA/TiO 2 nanocomposites were prepared using sonication and solution casting method at different weight percent TiO 2 . The aims of adding TiO 2 in the PMMA is to study the effects of TiO 2 nanofiller on the thermal properties nanocomposites. FESEM results show the higher amounts of TiO 2 in PMMA increase the rough surface morphology of the samples. Further, the Raman results reveal that the TiO 2 nanofiller were successfully intercalated into the PMMA matrix. In addition, the thermal properties of nanocomposited PMMA/TiO 2 nanocomposites were increased with the addition of TiO 2 in the PMMA.

  16. Optical properties of ZrO2, SiO2 and TiO2-SiO2 xerogels and coatings doped with Eu3+ and Eu2+

    Directory of Open Access Journals (Sweden)

    Gonçalves Rogéria R.

    1999-01-01

    Full Text Available Eu3+ doped bulk monoliths and thin films were obtained by sol-gel methods in the ZrO2, SiO2 and SiO2-TiO2 systems. Eu3+ 5D0 ® 7FJ emission and decay time characteristics were measured during the entire experimental preparation route from the initial sol to the final xerogels. The crystalline phases identified were tetragonal ZrO2 and mixtures of rutile and anatase TiO2 at high temperature treatments in bulk samples. Good quality thin films were obtained for all systems by dip-coating optical glasses (Schott BK270. The same spectroscopic features were observed either for the bulk monoliths or the films. By appropriate heat treatments under H2 atmosphere Eu2+ containing samples could be obtained in the SiO2-TiO2 system.

  17. HVOF-Sprayed Nano TiO2-HA Coatings Exhibiting Enhanced Biocompatibility

    Science.gov (United States)

    Lima, R. S.; Dimitrievska, S.; Bureau, M. N.; Marple, B. R.; Petit, A.; Mwale, F.; Antoniou, J.

    2010-01-01

    Biomedical thermal spray coatings produced via high-velocity oxy-fuel (HVOF) from nanostructured titania (n-TiO2) and 10 wt.% hydroxyapatite (HA) (n-TiO2-10wt.%HA) powders have been engineered as possible future alternatives to HA coatings deposited via air plasma spray (APS). This approach was chosen due to (i) the stability of TiO2 in the human body (i.e., no dissolution) and (ii) bond strength values on Ti-6Al-4V substrates more than two times higher than those of APS HA coatings. To explore the bioperformance of these novel materials and coatings, human mesenchymal stem cells (hMSCs) were cultured from 1 to 21 days on the surface of HVOF-sprayed n-TiO2 and n-TiO2-10 wt.%HA coatings. APS HA coatings and uncoated Ti-6Al-4V substrates were employed as controls. The profiles of the hMSCs were evaluated for (i) cellular proliferation, (ii) biochemical analysis of alkaline phosphatase (ALP) activity, (iii) cytoskeleton organization (fluorescent/confocal microscopy), and (iv) cell/substrate interaction via scanning electron microscopy (SEM). The biochemical analysis indicated that the hMSCs cultured on n-TiO2-10 wt.%HA coatings exhibited superior levels of bioactivity than hMSCs cultured on APS HA and pure n-TiO2 coatings. The cytoskeleton organization demonstrated a higher degree of cellular proliferation on the HVOF-sprayed n-TiO2-10wt.%HA coatings when compared to the control coatings. These results are considered promising for engineering improved performance in the next generation of thermally sprayed biomedical coatings.

  18. Microglial cells (BV-2) internalize titanium dioxide (TiO2) nanoparticles: toxicity and cellular responses.

    Science.gov (United States)

    Rihane, Naima; Nury, Thomas; M'rad, Imen; El Mir, Lassaad; Sakly, Mohsen; Amara, Salem; Lizard, Gérard

    2016-05-01

    Because of their whitening and photocatalytic effects, titanium dioxide nanoparticles (TiO2-NPs) are widely used in daily life. These NPs can be found in paints, plastics, papers, sunscreens, foods, medicines (pills), toothpastes, and cosmetics. However, the biological effect of TiO2-NPs on the human body, especially on the central nervous system, is still unclear. Many studies have demonstrated that the brain is one of the target organs in acute or chronic TiO2-NPs toxicity. The present study aimed to investigate the effect of TiO2-NPs at different concentrations (0.1 to 200 μg/mL) on murine microglial cells (BV-2) to assess their activity on cell growth and viability, as well as their neurotoxicity. Different parameters were measured: cell viability, cell proliferation and DNA content (SubG1 peak), mitochondrial depolarization, overproduction of reactive oxygen species (especially superoxide anions), and ultrastructural changes. Results showed that TiO2-NPs induced some cytotoxic effects with a slight inhibition of cell growth. Thus, at high concentrations, TiO2-NPs were not only able to inhibit cell adhesion but also enhanced cytoplasmic membrane permeability to propidium iodide associated with a loss of mitochondrial transmembrane potential and an overproduction of superoxide anions. No induction of apoptosis based on the presence of a SubG1 peak was detected. The microscopic observations also indicated that small groups of nanosized particles and micron-sized aggregates were engulfed by the BV-2 cells and sequestered as intracytoplasmic aggregates after 24-h exposure to TiO2-NPs. Altogether, our data show that the accumulation TiO2-NPs in microglial BV-2 cells favors mitochondrial dysfunctions and oxidative stress.

  19. Synthesis And Characterization Of SiO2, SnO2 And TiO2 Metal Oxide Shells Covering Cu2O Particles

    Directory of Open Access Journals (Sweden)

    Yu Ri

    2015-06-01

    Full Text Available In this work is described a means of improving the chemical stability of Cu2O@SiO2, Cu2O@SnO2 and Cu2O@TiO2 materials. The SiO2, SnO2 and TiO2 coated samples were stable from pH 3 to pH 10 for up to seven days. To determine the stability of the coated nanoparticles, and their colloidal solutions under acidic and basic conditions, colloidal nanoparticle solutions with various pH values were prepared and monitored over time. Details of the effect of variations in pH on the phase stability of core-shell type Cu2O were characterized using transmission electron microscopy and X-ray diffraction.

  20. Lung deflation and oxygen pulse in COPD: results from the NETT randomized trial.

    Science.gov (United States)

    Come, Carolyn E; Divo, Miguel J; San José Estépar, Raúl; Sciurba, Frank C; Criner, Gerard J; Marchetti, Nathaniel; Scharf, Steven M; Mosenifar, Zab; Make, Barry J; Keller, Cesar A; Minai, Omar A; Martinez, Fernando J; Han, MeiLan K; Reilly, John J; Celli, Bartolome R; Washko, George R

    2012-01-01

    In COPD patients, hyperinflation impairs cardiac function. We examined whether lung deflation improves oxygen pulse, a surrogate marker of stroke volume. In 129 NETT patients with cardiopulmonary exercise testing (CPET) and arterial blood gases (ABG substudy), hyperinflation was assessed with residual volume to total lung capacity ratio (RV/TLC), and cardiac function with oxygen pulse (O(2) pulse=VO(2)/HR) at baseline and 6 months. Medical and surgical patients were divided into "deflators" and "non-deflators" based on change in RV/TLC from baseline (∆RV/TLC). We defined deflation as the ∆RV/TLC experienced by 75% of surgical patients. We examined changes in O(2) pulse at peak and similar (iso-work) exercise. Findings were validated in 718 patients who underwent CPET without ABGs. In the ABG substudy, surgical and medical deflators improved their RV/TLC and peak O(2) pulse (median ∆RV/TLC -18.0% vs. -9.3%, p=0.0003; median ∆O(2) pulse 13.6% vs. 1.8%, p=0.12). Surgical deflators also improved iso-work O(2) pulse (0.53 mL/beat, p=0.04 at 20 W). In the validation cohort, surgical deflators experienced a greater improvement in peak O(2) pulse than medical deflators (mean 18.9% vs. 1.1%). In surgical deflators improvements in O(2) pulse at rest and during unloaded pedaling (0.32 mL/beat, pdeflators were 88% more likely than non-deflators to have an improvement in O(2) pulse (OR 1.88, 95% CI 1.30-2.72, p=0.0008). In COPD, decreased hyperinflation through lung volume reduction is associated with improved O(2) pulse. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Functionalized TiO2 nanoparticle containing isocyanate groups

    International Nuclear Information System (INIS)

    Ou, Baoli; Li, Duxin; Liu, Qingquan; Zhou, Zhihua; Liao, Bo

    2012-01-01

    Functionalized TiO 2 nanoparticle containing isocyanate groups can extend the TiO 2 nanoparticle chemistry, and may promote their many potential applications such as in polymer composites and coatings. This paper describes a facile method to prepare functionalized TiO 2 nanoparticle with highly reactive isocyanate groups on its surface, via the reaction between toluene-2, 4-diisocyanate (TDI) and hydroxyl on TiO 2 nanoparticle surface. The main effect factors on the reaction of TiO 2 with TDI were studied by determining the reaction extent of hydroxyl groups on TiO 2 surface. Fourier-transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed that reactive isocyanate groups were covalently attached to the TiO 2 nanoparticle surface. The dispersion of the TDI-functionalized TiO 2 nanoparticle was studied by transmission electron microscopy (TEM). Owing to the TDI molecules covalently bonded on TiO 2 nanoparticle surface, it was established that the TiO 2 nanoparticle can be uniformly dispersed in toluene, thus indicating that this functionalization method can prevent TiO 2 nanoparticle from agglomerating. -- Highlights: ► TiO 2 nanoparticle was functionalized with toluene-2, 4-diisocyanate. ► Functionalized TiO 2 nanoparticle can be uniformly dispersed in xylene. ► Compatibility of TiO 2 nanoparticle and organic solvent is significantly improved. ► TiO 2 containing isocyanate groups can extend the TiO 2 nanoparticle chemistry.

  2. Versatility of MnO2 for lithium battery applications

    CSIR Research Space (South Africa)

    Thackeray, MM

    1993-03-15

    Full Text Available , layered-MnO2, spinel-related Li2O.yMnO2 (y > = 2.5) and ramsdellite-MnO2 materials. An attempt has been made to clarify issues relating to the structural features of 'CDMO'-type materials that are prepared by the reaction of gamma-MnO2 with LiNO3 (or Li...

  3. Laser conditioning effect on HfO2/SiO2 film

    International Nuclear Information System (INIS)

    Wei Yaowei; Zhang Zhe; Liu Hao; Ouyang Sheng; Zheng Yi; Tang Gengyu; Chen Songlin; Ma Ping

    2013-01-01

    Laser conditioning is one of the important methods to improve the laser damage threshold of film optics. Firstly, a large aperture laser was used to irradiate the HfO 2 /SiO 2 reflectors, which were evaporated from hafnia and silica by e-beam. Secondly, a laser calorimeter was used to test the film absorption before and after laser irradiation. Focused ion beam (FIB) was few reported using on laser film, it was used to study the damage morphology and explore the cause of damage. The shooting of the partial ejection on nodule was obtained for the first time, which provided the basis for study the damage process. The results show that film absorption was decreased obviously after the laser irradiation, laser conditioning can raise the laser damage threshold by the 'cleaning mechanism'. For the HfO 2 /SiO 2 reflectors, laser conditioning was effective to eject the nodules on substrate. It resulted from the nodule residue not to affect the subsequent laser. In addition, laser conditioning was not effective to the nodule in the film, which might be from the material spatter in coating process. In this case, other method could be used to get rid of the nodules. (authors)

  4. Fabrication of ThO2, UO2, and PuO2-UO2 pellets

    International Nuclear Information System (INIS)

    Rasmussen, D.E.; Jentzen, W.R.; McCord, R.B.

    1978-01-01

    Fabrication of ThO pellets for EBR-II irradiation testing and fabrication of UO 2 and PuO 2 -UO 2 pellets for United Kingdom Prototype Fast Reactor (PFR) irradiation testing is discussed. Effect of process parameters on density and microstructure of pellets fabricated by the cold press and sinter technique is reviewed

  5. The Role of Phase Changes in TiO2/Pt/TiO2 Filaments

    Science.gov (United States)

    Bíró, Ferenc; Hajnal, Zoltán; Dücső, Csaba; Bársony, István

    2018-04-01

    This work analyses the role of phase changes in TiO2/Pt/TiO2 layer stacks for micro-heater application regarding their stability and reliable operation. The polycrystalline Pt layer wrapped in a TiO2 adhesion layer underwent a continuous recrystallisation in a self-heating operation causing a drift in the resistance ( R) versus temperature ( T) performance. Simultaneously, the TiO2 adhesion layer also deteriorates at high temperature by phase changes from amorphous to anatase and rutile crystallite formation, which not only influences the Pt diffusion in different migration phenomena, but also reduces the cross section of the Pt heater wire. Thorough scanning electron microscopy, energy dispersive spectroscopy, cross-sectional transmission electron microscopy (XTEM) and electron beam diffraction analysis of the structures operated at increasing temperature revealed the elemental structural processes leading to the instabilities and the accelerated degradation, resulting in rapid breakdown of the heater wire. Owing to stability and reliability criteria, the conditions for safe operation of these layer structures could be determined.

  6. HfO2 and SiO2 as barriers in magnetic tunneling junctions

    Science.gov (United States)

    Shukla, Gokaran; Archer, Thomas; Sanvito, Stefano

    2017-05-01

    SiO2 and HfO2 are both high-k, wide-gap semiconductors, currently used in the microelectronic industry as gate barriers. Here we investigate whether the same materials can be employed to make magnetic tunnel junctions, which in principle can be amenable for integration in conventional Si technology. By using a combination of density functional theory and the nonequilibrium Green's functions method for quantum transport we have studied the transport properties of Co [0001 ] /SiO2[001 ] /Co [0001 ] and Fe [001 ] /HfO2[001 ] /Fe [001 ] junctions. In both cases we found a quite large magnetoresistance, which is explained through the analysis of the real band structure of the magnets and the complex one of the insulator. We find that there is no symmetry spin filtering for the Co-based junction since the high transmission Δ2' band crosses the Fermi level, EF, for both spin directions. However, the fact that Co is a strong ferromagnet makes the orbital contribution to the two Δ2' spin subbands different, yielding magnetoresistance. In contrast for the Fe-based junction symmetry filtering is active for an energy window spanning between the Fermi level and 1 eV below EF, with Δ1 symmetry contributing to the transmission.

  7. Increased photocatalytic activity induced by TiO2/Pt/SnO2 heterostructured films

    Science.gov (United States)

    Testoni, Glaucio O.; Amoresi, Rafael A. C.; Lustosa, Glauco M. M. M.; Costa, João P. C.; Nogueira, Marcelo V.; Ruiz, Miguel; Zaghete, Maria A.; Perazolli, Leinig A.

    2018-02-01

    In this work, a high photocatalytic activity was attained by intercalating a Pt layer between SnO2 and TiO2 semiconductors, which yielded a TiO2/Pt/SnO2 - type heterostructure used in the discoloration of blue methylene (MB) solution. The porous films and platinum layer were obtained by electrophoretic deposition and DC Sputtering, respectively, and were both characterized morphologically and structurally by FE-SEM and XRD. The films with the Pt interlayer were evaluated by photocatalytic activity through exposure to UV light. An increase in efficiency of 22% was obtained for these films compared to those without platinum deposition. Studies on the reutilization of the films pointed out high efficiency and recovery of the photocatalyst, rendering the methodology favorable for the construction of fixed bed photocatalytic reactors. A proposal associated with the mechanism is discussed in this work in terms of the difference in Schottky barrier between the semiconductors and the electrons transfer and trapping cycle. These are fundamental factors for boosting photocatalytic efficiency.

  8. Selective adsorption of thiophenic compounds from fuel over TiO2/SiO2 under UV-irradiation.

    Science.gov (United States)

    Miao, Guang; Ye, Feiyan; Wu, Luoming; Ren, Xiaoling; Xiao, Jing; Li, Zhong; Wang, Haihui

    2015-12-30

    This study investigates selective adsorption of thiophenic compounds from fuel over TiO2/SiO2 under UV-irradiation. The TiO2/SiO2 adsorbents were prepared and then characterized by N2 adsorption, X-ray diffraction and X-ray photoelectron spectroscopy. Adsorption isotherms, selectivity and kinetics of TiO2/SiO2 were measured in a UV built-in batch reactor. It was concluded that (a) with the employment of UV-irradiation, high organosulfur uptake of 5.12 mg/g was achieved on the optimized 0.3TiO2/0.7SiO2 adsorbent at low sulfur concentration of 15 ppmw-S, and its adsorption selectivity over naphthalene was up to 325.5; (b) highly dispersed TiO2 served as the photocatalytic sites for DBT oxidation, while SiO2 acted as the selective adsorption sites for the corresponding oxidized DBT using TiO2 as a promoter, the two types of active sites worked cooperatively to achieve the high adsorption selectivity of TiO2/SiO2; (c) The kinetic rate-determining step for the UV photocatalysis-assisted adsorptive desulfurization (PADS) over TiO2/SiO2 was DBT oxidation; (d) consecutive adsorption-regeneration cycles suggested that the 0.3TiO2/0.7SiO2 adsorbent can be regenerated by acetonitrile washing followed with oxidative air treatment. This work demonstrated an effective PADS approach to greatly enhance adsorption capacity and selectivity of thiophenic compounds at low concentrations for deep desulfurization under ambient conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. A Facile Method for Loading CeO2 Nanoparticles on Anodic TiO2 Nanotube Arrays.

    Science.gov (United States)

    Liao, Yulong; Yuan, Botao; Zhang, Dainan; Wang, Xiaoyi; Li, Yuanxun; Wen, Qiye; Zhang, Huaiwu; Zhong, Zhiyong

    2018-04-03

    In this paper, a facile method was proposed to load CeO 2 nanoparticles (NPs) on anodic TiO 2 nanotube (NT) arrays, which leads to a formation of CeO 2 /TiO 2 heterojunctions. Highly ordered anatase phase TiO 2 NT arrays were fabricated by using anodic oxidation method, then these individual TiO 2 NTs were used as tiny "nano-containers" to load a small amount of Ce(NO 3 ) 3 solutions. The loaded anodic TiO 2 NTs were baked and heated to a high temperature of 450 °C, under which the Ce(NO 3 ) 3 would be thermally decomposed inside those nano-containers. After the thermal decomposition of Ce(NO 3 ) 3 , cubic crystal CeO 2 NPs were obtained and successfully loaded into the anodic TiO 2 NT arrays. The prepared CeO 2 /TiO 2 heterojunction structures were characterized by a variety of analytical technologies, including XRD, SEM, and Raman spectra. This study provides a facile approach to prepare CeO 2 /TiO 2 films, which could be very useful for environmental and energy-related areas.

  10. Fabrication of Nano-CeO2 and Application of Nano-CeO2 in Fe Matrix Composites

    International Nuclear Information System (INIS)

    Tiebao, W.; Chunxiang, C.; Xiaodong, W.; Guobin, L.

    2010-01-01

    It is expatiated that nano-CeO2 is fabricated by the direct sedimentation method. The components and particles diameter of nano-CeO2 powders are analyzed by XRD and SEM . The thermodynamic analysis and acting mechanism of nano-CeO2 with Al in Fe matrix composites are researched, which shows that the reaction is generated between CeO2 and Al in the composite, that is, 3CeO2+4Al - 2Al2O3+3[Ce], which obtains Al2O3 and active [Ce] during the sintering process. The active [Ce] can improve the performance of CeO2/Fe matrix composites. The suitable amount of CeO2 is about 0.05% in CeO2/Fe matrix composites. SEM fracture analysis shows that the toughness sockets in nano-CeO2/Fe matrix composites are more than those in no-added nano-CeO2 composites, which can explain that adding nano-CeO2 into Fe matrix composite, the toughness of the composite is improved significantly. Applied nano-CeO2 to Fe matrix diamond saw blades shows that Fe matrix diamond saw blade is sharper and of longer cutting life than that with no-added nano-CeO2.

  11. Highly sensitive electrochemical determination of 1-naphthol based on high-index facet SnO2 modified electrode

    International Nuclear Information System (INIS)

    Huang Xiaofeng; Zhao Guohua; Liu Meichuan; Li Fengting; Qiao Junlian; Zhao Sichen

    2012-01-01

    Highlights: ► It is the first time to employ high-index faceted SnO 2 in electrochemical analysis. ► High-index faceted SnO 2 has excellent electrochemical activity toward 1-naphthol. ► Highly sensitive determination of 1-naphthol is realized on high-index faceted SnO 2 . ► The detection limit of 1-naphthol is as low as 5 nM on high-index faceted SnO 2 . ► Electro-oxidation kinetics for 1-napthol on the novel electrode is discussed. - Abstract: SnO 2 nanooctahedron with {2 2 1} high-index facet (HIF) was synthesized by a simple hydrothermal method, and was firstly employed to sensitive electrochemical sensing of a typical organic pollutant, 1-naphthol (1-NAP). The constructed HIF SnO 2 modified glassy carbon electrode (HIF SnO 2 /GCE) possessed advantages of large effective electrode area, high electron transfer rate, and low charge transfer resistance. These improved electrochemical properties allowed the high electrocatalytic performance, high effective active sites and high adsorption capacity of 1-NAP on HIF SnO 2 /GCE. Cyclic voltammetry (CV) results showed that the electrochemical oxidation of 1-NAP obeyed a two-electron transfer process and the electrode reaction was under diffusion control on HIF SnO 2 /GCE. By adopting differential pulse voltammetry (DPV), electrochemical detection of 1-NAP was conducted on HIF SnO 2 /GCE with a limit of detection as low as 5 nM, which was relatively low compared to the literatures. The electrode also illustrated good stability in comparison with those reported value. Satisfactory results were obtained with average recoveries in the range of 99.7–103.6% in the real water sample detection. A promising device for the electrochemical detection of 1-NAP with high sensitivity has therefore been provided.

  12. Photocatalytic Removal of Phenol under Natural Sunlight over N-TiO2-SiO2 Catalyst: The Effect of Nitrogen Composition in TiO2-SiO2

    Directory of Open Access Journals (Sweden)

    Viet-Cuong Nguyen

    2009-01-01

    Full Text Available In this present work, high specific surface area and strong visible light absorption nitrogen doped TiO2-SiO2 photocatalyst was synthesized by using sol-gel coupled with hydrothermal treatment method. Nitrogen was found to improve the specific surface area while it also distorted the crystal phase of the resulting N-TiO2-SiO2 catalyst. As the N/ (TiO2-SiO2 molar ratio was more than 10%, the derived catalyst presented the superior specific surface area up to 260 m2/g. Nevertheless, its photoactivity towards phenol removal was observed to significantly decrease, which could results from the too low crystallinity. The nitrogen content in N-TiO2-SiO2 catalyst was therefore necessary to be optimized in terms of phenol removal efficiency and found at ca. 5%. Under UVA light and natural sunlight irradiation of 80 min, N(5%-TiO2-SiO2 catalyst presented the phenol decomposition efficiencies of 68 and 100%, respectively. It was also interestingly found in this study that the reaction rate was successfully expressed using a Langmuir-Hinshelwood (L-H model, indicating the L-H nature of photocatalytic phenol decomposition reaction on the N-TiO2-SiO2 catalyst.

  13. Controlled Directional Growth of TiO2 Nanotubes

    DEFF Research Database (Denmark)

    In, Su-il; Hou, Yidong; Abrams, Billie

    2010-01-01

    We demonstrate how the anodization direction and growth rate of vertically aligned, highly ordered TiO2 nanotube (NT) arrays can be controlled and manipulated by the local concentration of O-2 in the electrolyte. This leads to the growth of highly active TiO2 NT arrays directly on nonconducting s...

  14. Preparation, characterization and photocatalytic activity of TiO2 ...

    Indian Academy of Sciences (India)

    Photocatalyst; TiO2 nanoparticle; polyaniline; conducting polymer; core-shell nanocomposite. 1. Introduction ..... tine TiO2 nanoparticles, HCl-doped PANI and PANI/TiO2 ..... Karim M R, Lim K T, Lee M S, Kim K and Yeum J H 2009 Synth. Met.

  15. Facile hydrothermal synthesis of CeO 2 nanopebbles

    Indian Academy of Sciences (India)

    Cerium oxide (CeO2) nanopebbles have been synthesized using a facile hydrothermal method. X-ray diffraction pattern (XRD) and transmission electron microscopy analyses confirm the presence of CeO2 nanopebbles. XRD shows the formation of cubic fluorite CeO2 and the average particle size estimated from the ...

  16. A new semi-invasive method for two dimensional pO2 measurements of cortical structures.

    Science.gov (United States)

    Warnat, Jan; Liebsch, Gregor; Stoerr, Eva-Maria; Brawanski, Alexander; Woertgen, Chris

    2008-01-01

    Measuring brain oxygenation in patients with TBI or SAH is of major interest. We present a new semi-invasive method for two dimensional measurements of cortical pO2. For this feasibility study, a porphyrin containing sensor foil was placed directly on the cortex of intubated and variably ventilated Wistar rats. The sensor was excited with a light pulse and pictures of the foil's pO2 dependant emissions were captured with a CCD camera. After online data processing, two-dimensional maps of cortex oxygenation were displayed and analyzed using ROIs (here: arteriole, vein, parenchyma) with a display rate of 7 Hz. The size of one single measurement pixel was 0.03 x 0.03 mm2. The mean pO2 over cortex arterioles was 20.3 +/- 0.69, over veins 17.1 +/- 0.5 and over parenchyma 9.1 +/- 0.6 (mmHg +/- SD). The arterial pO2 showed a good correlation to the pO2 in the ROIs (r = 0.46-0.72, p pO2 values in the ROIs of the cortex. This prototype is capable of obtaining cortical pO2 maps with excellent temporal and spatial resolution and provides simultaneous imaging of the cortex structures.

  17. Bioactivity studies on TiO2-bearing Na2O–CaO–SiO2–B2O3 glasses

    International Nuclear Information System (INIS)

    Jagan Mohini, G.; Sahaya Baskaran, G.; Ravi Kumar, V.; Piasecki, M.; Veeraiah, N.

    2015-01-01

    Soda lime silica borate glasses mixed with different concentrations of TiO 2 are synthesized by the melt-quenching technique. As a part of study on bioactivity of these glasses, the samples were immersed in simulated body fluid (SBF) solution for prolonged times (~ 21 days) during which weight loss along with pH measurements is carried out at specific intervals of time. The XRD and SEM analyses of post-immersed samples confirm the formation of crystalline hydroxyapatite layer (HA) on the surface of the samples. To assess the role of TiO 2 on the formation of HA layer and degradability of the samples the spectroscopic studies viz. optical absorption and IR spectral studies on post- and pre-immersed samples have been carried out. The analysis of the results of degradability together with spectroscopic studies as a function of TiO 2 concentration indicated that about 6.0 mol% of TiO 2 is the optimal concentration for achieving better bioactivity of these glasses. The presence of the maximal concentration octahedral titanium ions in this glass that facilitates the formation of HA layer is found to be the reason for such a higher bioactivity. - Highlights: • Soda lime silica borate glasses mixed with TiO 2 are synthesized. • Bioactivity of the glasses is studied by immersing them in SBF solution. • XRD and SEM studies indicated the formation of hydroxyapatite layer on the surface. • Quantum of degradability is the highest in the glasses mixed with 6.0 mol% of TiO 2. • The results are analyzed using IR and optical absorption studies

  18. Peak Pressures and PaO2/FiO2 Ratios Are Associated With Adverse Outcomes in Patients on Mechanical Ventilators.

    Science.gov (United States)

    Whiting, Jeremy; Edriss, Hawa; Yang, Shengping; Nugent, Kenneth

    2016-06-01

    Patients requiring mechanical ventilation can have complications related to their underlying diseases and hospital-related events. It is possible that easily obtained information early in the course of mechanical ventilation can provide information about important outcomes. Medical records from 281 episodes of mechanical ventilation in the medical intensive care unit were reviewed to collect information on patient demographics, admitting diagnoses, laboratory tests, duration of mechanical ventilation, the development of ventilator-associated events and mortality. Ventilator pressures from day 2 were analyzed for this study. Most patients (72.7%) were ≥50 years, 53.8% were men and 66.3% had a body mass index (BMI) ≥ 25kg/m(2).The mean Acute Physiology and Chronic Healthy Evaluation II score was 13.6 ± 5.9. The median initial PaO2/FiO2 was 240 with interquartile range of 177-414. The median duration of ventilation was 4 days (interquartile range: 2-9 days). A PaO2/FiO2 ratio 500, and a BMI > 30kg/m(2) was associated with decreased mortality compared with normal BMIs. A PaO2/FiO2 ratio 30kg/m(2) were all associated with having a ventilator-associated event. There was a positive correlation between peak pressure (day 2) and the duration of ventilation (r = 0.263, P = 0.007). Easily available information collected on day 2 of mechanical ventilation can help identify patients at risk for poor outcomes, including the duration of mechanical ventilation, the development of ventilator-associated complications and mortality. Prospective studies measuring peak pressures are needed to evaluate the utility of this simple measurement in the management of patients requiring mechanical ventilation. Published by Elsevier Inc.

  19. Low-temperature sputtering of crystalline TiO2 films

    International Nuclear Information System (INIS)

    Musil, J.; Herman, D.; Sicha, J.

    2006-01-01

    This article reports on the investigation of reactive magnetron sputtering of transparent, crystalline titanium dioxide films. The aim of this investigation is to determine a minimum substrate surface temperature T surf necessary to form crystalline TiO 2 films with anatase structure. Films were prepared by dc pulsed reactive magnetron sputtering using a dual magnetron operating in bipolar mode and equipped with Ti(99.5) and ceramic Ti 5 O 9 targets. The films were deposited on unheated glass substrates and their structure was characterized by x-ray diffraction and surface morphology by atomic force microscopy. Special attention is devoted to the measurement of T surf using thermostrips pasted to the glass substrate. It was found that (1) T surf is considerably higher (approximately by 100 deg. C or more) than the substrate temperature T s measured by the thermocouple incorporated into the substrate holder and (2) T surf strongly depends on the substrate-to-target distance d s-t , the magnetron target power loading, and the thermal conductivity of the target and its cooling. The main result of this study is the finding that (1) the crystallization of sputtered TiO 2 films depends not only on T surf but also on the total pressure p T of sputtering gas (Ar+O 2 ), partial pressure of oxygen p O 2 , the film deposition rate a D , and the film thickness h (2) crystalline TiO 2 films with well developed anatase structure can be formed at T surf =160 deg. C and low values of a D ≅5 nm/min (3) the crystalline structure of TiO 2 film gradually changes from (i) anatase through (ii) anatase+rutile mixture, and (iii) pure rutile to x-ray amorphous structure at T surf =160 deg. C and p T =0.75 Pa when p O 2 decreases and a D increases above 5 nm/min, and (4) crystallinity of the TiO 2 films decreases with decreasing h and T surf . Interrelationships between the structure of TiO 2 film, its roughness, T surf , and a D are discussed in detail. Trends of next development are

  20. Chemically synthesized TiO2 and PANI/TiO2 thin films for ethanol sensing applications

    Science.gov (United States)

    Gawri, Isha; Ridhi, R.; Singh, K. P.; Tripathi, S. K.

    2018-02-01

    Ethanol sensing properties of chemically synthesized titanium dioxide (TiO2) and polyaniline/titanium dioxide nanocomposites (PANI/TiO2) had been performed at room temperature. In-situ oxidative polymerization process had been employed with aniline as a monomer in presence of anatase titanium dioxide nanoparticles. The prepared samples were structurally and morphologically characterized by x-ray diffraction, fourier transform infrared spectra, high resolution-transmission electron microscopy and field emission-scanning electron microscopy. The crystallinity of PANI/TiO2 nanocomposite was revealed by XRD and FTIR spectra confirmed the presence of chemical bonding between the polymer chains and metal oxide nanoparticles. HR-TEM micrographs depicted that TiO2 particles were embedded in polymer matrix, which provides an advantage over pure TiO2 nanoparticles in efficient adsorption of vapours. These images also revealed that the TiO2 nanoparticles were irregular in shape with size around 17 nm. FE-SEM studies revealed that in the porous structure of PANI/TiO2 film, the intercalation of TiO2 in PANI chains provides an advantage over pure TiO2 film for uniform interaction with ethanol vapors. The sensitivity values of prepared samples were examined towards ethanol vapours at room temperature. The PANI/TiO2 nanocomposite exhibited better sensing response and faster response-recovery examined at different ethanol concentrations ranging from 5 ppm to 20 ppm in comparison to pure TiO2 nanoparticles. The increase in vapour sensing of PANI/TiO2 sensing film as compared to pure TiO2 film had been explained in detail with the help of gas sensing mechanism of TiO2 and PANI/TiO2. This provides strong evidence that gas sensing properties of TiO2 had been considerably improved and enhanced with the addition of polymer matrix.

  1. Carbon encapsulated ultrasmall SnO2 nanoparticles anchoring on graphene/TiO2 nanoscrolls for lithium storage

    International Nuclear Information System (INIS)

    Li, Xinlu; Zhang, Yonglai; Li, Tongtao; Zhong, Qineng; Li, Hongyi; Huang, Jiamu

    2014-01-01

    Highlights: • Highly-dispersive ultrasmall SnO 2 nanoparticles (4∼8 nm) are anchored on the substrate of graphene/TiO 2 nanoscrolls. • The encapsulated glucose-derived carbon layer effectively immobilizes SnO 2 nanoparticles. • The enhanced cycling performance is owing to the synergetic effects between the multicomposites. - Abstract: Amorphous carbon is coated on the surface of ultrasmall SnO 2 nanoparticles which are anchored on graphene/TiO 2 nanoscrolls via hydrothermal treatment, followed by annealing process. Transmission electron microscope images show that ultrasmall SnO 2 nanoparticles are anchored on graphene/TiO 2 nanoscrolls and further immobilized by the outermost amorphous carbon layer. The carbon encapsulated SnO 2 @graphene/TiO 2 nanocomposites deliver high reversible capacities around 1131, 793, 621 and 476 mAh g −1 at the current densities of 100, 250, 500, and 1000 mA g −1 , respectively. It is found that SnO 2 nanoparticles play a dominant role in the contributions of reversible capacity according to the cyclic voltammetry curves, voltage-capacity curves and dQ/dV vs. potential curves. The substrate of graphene/TiO 2 nanoscrolls provides sufficient transport channels for lithium ions and high electron conductivity. While the outermost amorphous carbon layer prevents the peeling of SnO 2 nanoparticles from the substrate, therefore making them desirable alternative anode materials for lithium ion batteries

  2. Passivation of pigment-grade TiO2 particles by nanothick atomic layer deposited SiO2 films

    International Nuclear Information System (INIS)

    King, David M; Liang Xinhua; Weimer, Alan W; Burton, Beau B; Akhtar, M Kamal

    2008-01-01

    Pigment-grade TiO 2 particles were passivated using nanothick insulating films fabricated by atomic layer deposition (ALD). Conformal SiO 2 and Al 2 O 3 layers were coated onto anatase and rutile powders in a fluidized bed reactor. SiO 2 films were deposited using tris-dimethylaminosilane (TDMAS) and H 2 O 2 at 500 deg. C. Trimethylaluminum and water were used as precursors for Al 2 O 3 ALD at 177 deg. C. The photocatalytic activity of anatase pigment-grade TiO 2 was decreased by 98% after the deposition of 2 nm SiO 2 films. H 2 SO 4 digest tests were performed to exhibit the pinhole-free nature of the coatings and the TiO 2 digest rate was 40 times faster for uncoated TiO 2 than SiO 2 coated over a 24 h period. Mass spectrometry was used to monitor reaction progress and allowed for dosing time optimization. These results demonstrate that the TDMAS-H 2 O 2 chemistry can deposit high quality, fully dense SiO 2 films on high radius of curvature substrates. Particle ALD is a viable passivation method for pigment-grade TiO 2 particles

  3. Facile fabrication of robust TiO2@SnO2@C hollow nanobelts for outstanding lithium storage

    Science.gov (United States)

    Tian, Qinghua; Li, Lingxiangyu; Chen, Jizhang; Yang, Li; Hirano, Shin-ichi

    2018-02-01

    Elaborate fabrication of state-of-the-art nanostructure SnO2@C-based composites greatly contributes to alleviate the huge volume expansion issue of the SnO2 anodes. But the preparation processes of most of them are complicated and tedious, which is generally adverse to the development of SnO2@C-based composite anodes. Herein, a unique nanostructure of TiO2@SnO2@C hollow nanobelts (TiO2@SnO2@C HNBs), including the characteristics of one-dimensional architecture, sandwich protection, hollow structure, carbon coating, and a mechanically robust TiO2 support, has been fabricated by a facile approach for the first time. As anodes for lithium-ion batteries, the as-fabricated TiO2@SnO2@C HNBs exhibit an outstanding lithium storage performance, delivering capacity of 804.6 and 384. 5 mAh g-1 at 200 and even 1000 mA g-1 after 500 cycles, respectively. It is demonstrated that thus outstanding performance is mainly attributed to the unique nanostructure of TiO2@SnO2@C HNBs.

  4. Investigation on the structural and nonlinear optical properties of Pt doped TiO2 nanoparticles

    International Nuclear Information System (INIS)

    Rahulan, K. Mani; Padmanathan, N.; Vinitha, G.; Kanakam, Charles Christopher

    2013-01-01

    Graphical abstract: The open aperture Z-scan traces of Pt doped TiO 2 nanoparticles at different Pt concentrations were carried out at an irradiation wavelength of 532 nm. It was numerically found that, two photon absorption (TPA) type process gives the best fit to the obtained open aperture Z-scan data. The nonlinear transmission was found to be of third order as it fits to a two-photon absorption. The optical limiting performances of nanoparticles were greatly enhanced with increased volume ratio of Pt. Increasing particle size reduced the limiting threshold and enhanced the optical limiting performance. - Highlights: • Pt doped TiO 2 nanoparticles with different concentrations of Pt have been synthesized by sol–gel method. • The average fluorescence lifetime decreases as the volume fraction of Pt dopant increases. • The effects of Pt content on the optical limiting property were investigated by open aperture Z-scan measurements done at 532 nm using 5 ns laser pulses. • The values of the third-order nonlinearities of nanoparticles are interesting from the application point of view which could be used as a potential candidate for the application of nonlinear optical device. - Abstract: Pt doped TiO 2 nanoparticles with different concentrations of Pt were prepared by sol–gel method. X-ray diffraction (XRD) study reveals that the samples have a homogeneous anatase phase tetragonal system and the lattice parameter analysis indicates that Pt ions substitute into the lattice of TiO 2 . The addition of dopant increases the growth of TiO 2 grains, agglomerates them and shifts the absorption band of TiO 2 from ultraviolet to visible region. The incorporation of Pt in TiO 2 is also confirmed by fluorescence quenching and the fluorescence lifetime decreases as the volume fraction of Pt dopant increases. Open aperture Z-scan measurements done at 532 nm using 7 ns laser pulses show nonlinear absorption which arises from an effective two photon absorption process

  5. Structural, electrical, and optical properties of polycrystalline NbO_2 thin films grown on glass substrates by solid phase crystallization

    International Nuclear Information System (INIS)

    Nakao, Shoichiro; Kamisaka, Hideyuki; Hirose, Yasushi; Hasegawa, Tetsuya

    2017-01-01

    We investigated the structural, electrical, and optical properties of polycrystalline NbO_2 thin films on glass substrates. The NbO_2 films were crystallized from amorphous precursor films grown by pulsed laser deposition at various oxygen partial pressures (P_O_2). The electrical and optical properties of the precursor films systematically changed with P_O_2, demonstrating that the oxygen content of the precursor films can be finely controlled with P_O_2. The precursors were crystallized into polycrystalline NbO_2 films by annealing under vacuum at 600 C. The NbO_2 films possessed extremely flat surfaces with branching patterns. Even optimized films showed a low resistivity (ρ) of 2 x 10"2 Ω cm, which is much lower than the bulk value of 1 x 10"4 Ω cm, probably because of the inferior crystallinity of the films compared with that of a bulk NbO_2 crystal. Both oxygen-rich and -poor NbO_2 films showed lower ρ than that of the stoichiometric film. The NbO_2 film with the highest ρ showed an indirect bandgap of 0.7 eV. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. TiO2 beads and TiO2-chitosan beads for urease immobilization

    International Nuclear Information System (INIS)

    Ispirli Doğaç, Yasemin; Deveci, İlyas; Teke, Mustafa; Mercimek, Bedrettin

    2014-01-01

    The aim of the present study is to synthesize TiO 2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO 2 beads. In the first method (A), urease enzyme was immobilized onto TiO 2 beads by adsorption and then crosslinking. In the second method (B), TiO 2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2 mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5 mg/ml for A and 1.0 mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0 mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4–70 °C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30 °C (A), 40 °C (B) and 35 °C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65 °C. However, at this temperature free urease protected only 15% activity. - Highlights: • TiO 2 and TiO 2 -chitosan beads for urease immobilization have been prepared and characterized. • The beads used in this work are good matrices for the immobilization of urease. • The immobilized urease was shown to have good properties and stabilities (pH and thermal stability, operational stability). • The 50

  7. Isolated centres versus defect associates in Sm3+-doped CeO2: a spectroscopic investigation

    International Nuclear Information System (INIS)

    Tiseanu, Carmen; Avram, Daniel; Cojocaru, Bogdan; Parvulescu, Vasile I; Vela-Gonzalez, Andrea V; Sanchez-Dominguez, Margarita

    2013-01-01

    The interactions between Sm 3+ and oxygen vacancies in CeO 2 are probed by the use of tuneable laser excited time-resolved photoluminescence and Raman spectroscopies. It is found that Sm 3+ (with doping concentrations of 0.1, 0.3, 1 and 5 wt%) substitutes largely for Ce 4+ in sites with cubic symmetry and the corresponding emission is sensitized via the Ce 4+ –O 2− charge-transfer band of CeO 2 . It is established from the photoluminescence spectra measured at long delay after the laser pulse that the local environment around cubic Sm 3+ centres is not changed with concentration and ceria size. In addition to cubic symmetry Sm 3+ centres, low-symmetry Sm 3+ centres tentatively assigned to the Sm 3+ –oxygen vacancy associates of nearest-neighbour type are also observed. Their emission is preferentially excited via the weak f–f absorption transitions of Sm 3+ . A relatively strong concentration-induced quenching of Sm 3+ emission was inferred from the decrease in the average emission lifetimes from 2.1 ms (0.1 wt%) to 0.87 ms (5 wt%). The local environments of Sm 3+ and Eu 3+ in CeO 2 are also compared on the basis of their emission spectra and decays. (paper)

  8. Novel transparent conducting oxide: Anatase Ti1-xNb xO2

    International Nuclear Information System (INIS)

    Furubayashi, Yutaka; Hitosugi, Taro; Yamamoto, Yukio; Hirose, Yasushi; Kinoda, Go; Inaba, Kazuhisa; Shimada, Toshihiro; Hasegawa, Tetsuya

    2006-01-01

    Single-crystalline Ti 1-x Nb x O 2 (x = 0.2) films of 40 nm thickness were deposited on SrTiO 3 (100) substrates by the pulsed laser deposition (PLD) technique. X-ray diffraction measurement confirmed epitaxial growth of anatase (001) film. The resistivity of Ti 1-x Nb x O 2 films with x ≥ 0.03 is 2-3 x 10 -4 Ω cm at room temperature. The carrier density of Ti 1-x Nb x O 2 , which is almost proportional to the Nb concentration, can be controlled in a range of 1 x 10 19 to 2 x 10 21 cm -3 . Optical measurements revealed that internal transmittance in the visible and near-infrared region for films with x = 0.03 was more than 97%. These results demonstrate that the presently developed anatase Ti 1-x Nb x O 2 is one of the promising candidates for the practical TCOs

  9. Graphene/SnO2 nanocomposite-modified electrode for electrochemical detection of dopamine

    Directory of Open Access Journals (Sweden)

    R. Nurzulaikha

    2015-09-01

    Full Text Available A graphene-tin oxide (G-SnO2 nanocomposite was prepared via a facile hydrothermal route using graphene oxide and Sn precursor solution without addition of any surfactant. The hydrothermally synthesized G-SnO2 nanocomposite was characterized using a field emission scanning electron microscope (FESEM, high resolution transmission electron microscope (HRTEM, X-ray diffraction (XRD, and energy dispersive spectroscopy (EDS. A homogeneous deposition of SnO2 nanoparticles with an average particle size of 10 nm on the graphene was observed in the FESEM and HRTEM images. The G-SnO2 nanocomposite was used to fabricate a modified electrode for the electrochemical detection of dopamine (DA in the presence of ascorbic acid (AA. Differential pulse voltammetry (DPV showed a limit of detection (LoD of 1 μM (S/N = 3 in the presence of ascorbic acid (AA. Keywords: Graphene, Tin oxide, Nanocomposite, Electrochemical sensor, Biosensor, Dopamine

  10. Efficacy analysis of LDPC coded APSK modulated differential space-time-frequency coded for wireless body area network using MB-pulsed OFDM UWB technology.

    Science.gov (United States)

    Manimegalai, C T; Gauni, Sabitha; Kalimuthu, K

    2017-12-04

    Wireless body area network (WBAN) is a breakthrough technology in healthcare areas such as hospital and telemedicine. The human body has a complex mixture of different tissues. It is expected that the nature of propagation of electromagnetic signals is distinct in each of these tissues. This forms the base for the WBAN, which is different from other environments. In this paper, the knowledge of Ultra Wide Band (UWB) channel is explored in the WBAN (IEEE 802.15.6) system. The measurements of parameters in frequency range from 3.1-10.6 GHz are taken. The proposed system, transmits data up to 480 Mbps by using LDPC coded APSK Modulated Differential Space-Time-Frequency Coded MB-OFDM to increase the throughput and power efficiency.

  11. Optimized nanostructured TiO2 photocatalysts

    Science.gov (United States)

    Topcu, Selda; Jodhani, Gagan; Gouma, Pelagia

    2016-07-01

    Titania is the most widely studied photocatalyst. In it’s mixed-phase configuration (anatase-rutile form) -as manifested in the commercially available P25 Degussa material- titania was previously found to exhibit the best photocatalytic properties reported for the pure system. A great deal of published research by various workers in the field have not fully explained the underlying mechanism for the observed behavior of mixed-phase titania photocatalysts. One of the prevalent hypothesis in the literature that is tested in this work involves the presence of small, active clusters of interwoven anatase and rutile crystallites or “catalytic “hot-spots””. Therefore, non-woven nanofibrous mats of titania were produced and upon calcination the mats consisted of nanostructured fibers with different anatase-rutile ratios. By assessing the photocatalytic and photoelectrochemical properties of these samples the optimized photocatalyst was determined. This consisted of TiO2 nanostructures annealed at 500˚C with an anatase /rutile content of 90/10. Since the performance of this material exceeded that of P25 complete structural characterization was employed to understand the catalytic mechanism involved. It was determined that the dominant factors controlling the photocatalytic behavior of the titania system are the relative particle size of the different phases of titania and the growth of rutile laths on anatase grains which allow for rapid electron transfer between the two phases. This explains how to optimize the response of the pure system.

  12. H2O2 space shuttle APU

    Science.gov (United States)

    1975-01-01

    A cryogenic H2-O2 auxiliary power unit (APU) was developed and successfully demonstrated. It has potential application as a minimum weight alternate to the space shuttle baseline APU because of its (1) low specific propellant consumption and (2) heat sink capabilities that reduce the amount of expendable evaporants. A reference system was designed with the necessary heat exchangers, combustor, turbine-gearbox, valves, and electronic controls to provide 400 shp to two aircraft hydraulic pumps. Development testing was carried out first on the combustor and control valves. This was followed by development of the control subsystem including the controller, the hydrogen and oxygen control valves, the combustor, and a turbine simulator. The complete APU system was hot tested for 10 hr with ambient and cryogenic propellants. Demonstrated at 95 percent of design power was 2.25 lb/hp-hr. At 10 percent design power, specific propellant consumption was 4 lb/hp-hr with space simulated exhaust and 5.2 lb/hp-hr with ambient exhaust. A 10 percent specific propellant consumption improvement is possible with some seal modifications. It was demonstrated that APU power levels could be changed by several hundred horsepower in less than 100 msec without exceeding allowable turbine inlet temperatures or turbine speed.

  13. RuO2/MnO2 composite materials for high-performance supercapacitor electrodes

    Science.gov (United States)

    Jianming, Lei; Xiaomei, Chen

    2015-08-01

    Ruthenium oxide and manganese oxide nanomaterials were respectively prepared by a sol-gel process and hydrothermal synthesis method. The morphologies and microstructures of the composite nanomaterials were characterized by SEM and XRD. Based on the cyclic voltammetry, electrochemical impedance spectroscopy and constant current charge-discharge techniques, the performances of the electrodes were investigated. The results show that the composite of manganese oxide and ruthenium oxide is beneficial to improve the impedance characteristic. The electrode with 60% (mass ratio) manganese oxide has a high specific capacitance of 438 F/g and a lower inner resistance of 0.304 Ω using 38% (mass ratio) H2SO4 solution. The capacitance retention of RuO2/MnO2 composite electrode was 92.5% after 300 cycles.

  14. RuO2/MnO2 composite materials for high-performance supercapacitor electrodes

    International Nuclear Information System (INIS)

    Lei Jianming; Chen Xiaomei

    2015-01-01

    Ruthenium oxide and manganese oxide nanomaterials were respectively prepared by a sol–gel process and hydrothermal synthesis method. The morphologies and microstructures of the composite nanomaterials were characterized by SEM and XRD. Based on the cyclic voltammetry, electrochemical impedance spectroscopy and constant current charge–discharge techniques, the performances of the electrodes were investigated. The results show that the composite of manganese oxide and ruthenium oxide is beneficial to improve the impedance characteristic. The electrode with 60% (mass ratio) manganese oxide has a high specific capacitance of 438 F/g and a lower inner resistance of 0.304 Ω using 38% (mass ratio) H 2 SO 4 solution. The capacitance retention of RuO 2 /MnO 2 composite electrode was 92.5% after 300 cycles. (paper)

  15. Nanoparticulate anatase TiO2 (TiO2 NPs) upregulates the expression of silkworm (Bombyx mori) neuropeptide receptor and promotes silkworm feeding, growth, and silking.

    Science.gov (United States)

    Ni, Min; Zhang, Hua; Li, Fan Chi; Wang, Bin Bin; Xu, Kai Zun; Shen, Wei De; Li, Bing

    2015-06-01

    Bombyx mori orphan G protein-coupled receptor, BNGR-A4, is the specific receptor of B. mori neuropeptide F (BmNPFR, neuropeptide F designated NPF). BmNPFR binds specifically and efficiently to B. mori neuropeptides BmNPF1a and BmNPF1b, which activates the ERK1/2 signaling pathway to regulate B. mori food intake and growth. Titanium dioxide nanoparticles (TiO2 NPs) can promote B. mori growth. However, whether the mechanisms of TiO2 NPs' effects are correlated with BmNPFR remains unknown. In this study, the effects of TiO2 NPs (5mg/L) feeding and BmNPFR-dsRNA injection on B. mori food intake and growth were investigated; after TiO2 NPs treatments, B. mori food intake, body weight, and cocoon shell weight were 5.82%, 4.64%, and 9.30% higher, respectively, than those of controls. The food intake, body weight, and cocoon shell weight of the BmNPFR-dsRNA injection group were reduced by 8.05%, 6.28%, and 6.98%, respectively, compared to the control. After TiO2 NPs treatment for 72h, the transcriptional levels of BmNPFR, BmNPF1a, and BmNPF1b in the midgut were 1.58, 1.43, and 1.34-folds, respectively, of those of the control, but 1.99, 2.26, and 2.19-folds, respectively, of the BmNPFR-dsRNA injection group; the phosphorylation level of MAPK was 24.03% higher than the control, while the phosphorylation level of BmNPFR-dsRNA injection group was 71.00% of control. The results indicated that TiO2 NPs affect B. mori feeding and growth through increasing the expression of BmNPFR. This study helps clarify the roles of BmNPF/BmNPFR system in TiO2 NPs' effects on B. mori feeding, growth, and development. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Inhaled 239PuO2 in rats with pulmonary emphysema. II

    International Nuclear Information System (INIS)

    Lundgren, D.L.; Mauderly, J.L.; Carlton, W.W.; Hahn, F.F.

    1988-01-01

    The modifying effects of pre-existing pulmonary emphysema on deposition, distribution, retention, and effects of inhaled 239 PuO 2 in the rat were investigated. The presence of emphysema in the rats tested was indicated by respiratory function measurements and confirmed microscopically. Initial lung burdens of 239 Pu per kg body weight were less in rats with emphysema than in control rats; however, the retention of 239 Pu was similar in emphysematous and control rats. Survival and lung tumor occurrence were similar in emphysematous and control rats exposed to 239 PuO 2 . We concluded that rats with pre-existing pulmonary emphysema were not more sensitive to the effects of inhaled 239 PuO 2 than control rats. (author)

  17. Toxicity of 239PuO2 inhaled by aged Beagle dogs. X

    International Nuclear Information System (INIS)

    Muggenburg, B.A.; Hahn, F.F.; Gillett, N.A.; Guilmette, R.A.; Boecker, B.B.; McClellan, R.O.

    1988-01-01

    The influence of age at exposure on the metabolism, dosimetry, and biological effects of inhaled 239 PuO 2 particles is being studied in aged Beagle dogs (8.0-10.5 yr of age at exposure). Forty-eight dogs inhaled 239 PuO 2 particles with an activity median aerodynamic diameter of 1.5 mm to achieve graded levels of initial pulmonary burdens (IPB) ranging from 0.02-0.66 μCi 239 Pu/kg body weight (0.75-24 kBq/kg). Twelve other dogs were exposed to the aerosol diluent only. All forty-eight exposed dogs have died, including two in the past year. The twelve control dogs have also died, including one in the past year. Radiation pneumonitis and pulmonary fibrosis have been the primary causes of death in these aged dogs exposed to 239 PuO 2 . (author)

  18. Properties of water surface discharge at different pulse repetition rates

    International Nuclear Information System (INIS)

    Ruma,; Yoshihara, K.; Hosseini, S. H. R.; Sakugawa, T.; Akiyama, H.; Akiyama, M.; Lukeš, P.

    2014-01-01

    The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H 2 O 2 ) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H 2 O 2 and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.

  19. Natural CaO-TiO2-SiO2 based ceramics

    Directory of Open Access Journals (Sweden)

    Jelena Pantić

    2011-06-01

    Full Text Available Lešnica river deposits consist of a large number of minerals of different grain sizes including sphene. Since it is very difficult to obtain pure monophase titanite by different synthetic routes (sol-gel, coprecipitation, combustion, spray pyrolysis and hydrothermal method, the aim of this work was to study the structure of the sphene from the Lešnica river deposits and possibility of using it as a natural precursor for CaO-TiO2-SiO2 based ceramics. The sphene from Lešnica was analyzed by different methods: tristimulus colorimetry, infrared spectroscopy, electron microprobe and X-ray single crystal diffraction. It was confirmed that Al, Fe, Mn and P are present in the sphene structure and proposed that corresponding structural formula could be: (Ca2+1.008 Mn2+0.0021.010(Ti4+0.901 Fe3+0.033 Al3+0.060 P5+0.0010.995 Si4+1.024 O2-5.

  20. Structures and magnetic behaviours of TiO2–Mn–TiO2 multilayers

    International Nuclear Information System (INIS)

    Fa-Min, Liu; Peng, Ding; Jian-Qi, Li

    2010-01-01

    The TiO 2 -Mn-TiO 2 multilayers are successfully grown on glass and silicon substrates by alternately using radio frequency reactive magnetron sputtering and direct current magnetron sputtering. The structures and the magnetic behaviours of these films are characterised with x-ray diffraction, transmission electron microscope (TEM), vibrating sample magnetometer, and superconducting quantum interference device (SQUID). It is shown that the multi-film consists of a mixture of anatase and rutile TiO 2 with an embedded Mn nano-film. It is found that there are two turning points from ferromagnetic phase to antiferromagnetic phase. One is at 42 K attributed to interface coupling between ferromagnetic Mn 3 O 4 and antiferromagnetic Mn 2 O 3 , and the other is at 97 K owing to the interface coupling between ferromagnetic Mn and antiferromagnetic MnO. The samples are shown to have ferromagnetic behaviours at room temperature from hysteresis in the M-H loops, and their ferromagnetism is found to vary with the thickness of Mn nano-film. Moreover, the Mn nano-film has a critical thickness of about 18.5 nm, which makes the coercivity of the multi-film reach a maximum of about 3.965×10 −2 T. (cross-disciplinary physics and related areas of science and technology)

  1. [The spectra of a laser-produced plasma source with CO2, O2 and CF4 liquid aerosol spray target].

    Science.gov (United States)

    Ni, Qi-Liang; Chen, Bo

    2008-11-01

    A laser-produced plasma (LPP) source with liquid aerosol spray target and nanosecond laser was developed, based on both soft X-ray radiation metrology and extreme ultraviolet projection lithography (EUVL). The LPP source is composed of a stainless steel solenoid valve whose temperature can be continuously controlled, a Nd : YAG laser with pulse width, working wavelength and pulse energy being 7 ns, 1.064 microm and 1J respectively, and a pulse generator which can synchronously control the valve and the laser. A standard General Valve Corporation series 99 stainless steel solenoid valve with copper gasket seals and a Kel-F poppet are used in order to minimize leakage and poppet deformation during high-pressure cryogenic operation. A close fitting copper cooling jacket surrounds the valve body. The jacket clamps a copper coolant carrying tube 3 mm in diameter, which is fed by an automatically pressurized liquid nitrogen-filled dewar. The valve temperature can be controlled between 77 and 473 K. For sufficiently high backing pressure and low temperature, the valve reservoir gas can undergo a gas-to-liquid phase transition. Upon valve pulsing, the liquid is ejected into a vacuum and breaks up into droplets, which is called liquid aerosol spray target. For the above-mentioned LPP source, firstly, by the use of Cowan program on the basis of non-relativistic quantum mechanics, the authors computed the radiative transition wavelengths and probabilities in soft X-ray region for O4+, O5+, O6+, O7+, F5+, F6+ and F7+ ions which were correspondingly produced from the interaction of the 10(11)-10(12) W x cm(-2) power laser with liquid O2, CO2 and CF4 aerosol spray targets. Secondly, the authors measured the spectra of liquid O2, CO2 and CF4 aerosol spray target LPP sources in the 6-20 nm band for the 8 x 10(11) W x cm(-2) laser irradiance. The measured results were compared with the Cowan calculated results ones, and the radiative transition wavelength and probability for the

  2. Hybrid Pulsed Nd:YAG Laser

    Science.gov (United States)

    Miller, Sawyer; Trujillo, Skyler; Fort Lewis College Laser Group Team

    This work concerns the novel design of an inexpensive pulsed Nd:YAG laser, consisting of a hybrid Kerr Mode Lock (KLM) and Q-switch pulse. The two pulse generation systems work independently, non simultaneously of each other, thus generating the ability for the user to easily switch between ultra-short pulse widths or large energy density pulses. Traditionally, SF57 glass has been used as the Kerr medium. In this work, novel Kerr mode-locking mediums are being investigated including: tellurite compound glass (TeO2), carbon disulfide (CS2), and chalcogenide glass. These materials have a nonlinear index of refraction orders of magnitude,(n2), larger than SF57 glass. The Q-switched pulse will utilize a Pockels cell. As the two pulse generation systems cannot be operated simultaneously, the Pockels cell and Kerr medium are attached to kinematic mounts, allowing for quick interchange between systems. Pulse widths and repetition rates will vary between the two systems. A goal of 100 picosecond pulse widths are desired for the mode-locked system. A goal of 10 nanosecond pulse widths are desired for the Q-switch system, with a desired repetition rate of 50 Hz. As designed, the laser will be useful in imaging applications.

  3. Heterogeneous Ag-TiO2-SiO2 composite materials as novel catalytic systems for selective epoxidation of cyclohexene by H2O2.

    Directory of Open Access Journals (Sweden)

    Xin Wang

    Full Text Available TiO2-SiO2 composites were synthesized using cetyl trimethyl ammonium bromide (CTAB as the structure directing template. Self-assembly hexadecyltrimethyl- ammonium bromide TiO2-SiO2/(CTAB were soaked into silver nitrate (AgNO3 aqueous solution. The Ag-TiO2-SiO2(Ag-TS composite were prepared via a precipitation of AgBr in soaking process and its decomposition at calcination stage. Structural characterization of the materials was carried out by various techniques including X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, N2 adsorption-desorption and ultraviolet visible spectroscopy (UV-Vis. Characterization results revealed that Ag particles were incorporated into hierarchical TiO2-SiO2 without significantly affecting the structures of the supports. Further heating-treatment at 723 K was more favorable for enhancing the stability of the Ag-TS composite. The cyclohexene oxide was the major product in the epoxidation using H2O2 as the oxidant over the Ag-TS catalysts. Besides, the optimum catalytic activity and stability of Ag-TS catalysts were obtained under operational conditions of calcined at 723 K for 2 h, reaction time of 120 min, reaction temperature of 353 K, catalyst amount of 80 mg, aqueous H2O2 (30 wt.% as oxidant and chloroform as solvent. High catalytic activity with conversion rate up to 99.2% of cyclohexene oxide could be obtainable in water-bathing. The catalyst was found to be stable and could be reused three times without significant loss of catalytic activity under the optimized reaction conditions.

  4. Nanoscopic studies of domain structure dynamics in ferroelectric La:HfO2 capacitors

    Science.gov (United States)

    Buragohain, P.; Richter, C.; Schenk, T.; Lu, H.; Mikolajick, T.; Schroeder, U.; Gruverman, A.

    2018-05-01

    Visualization of domain structure evolution under an electrical bias has been carried out in ferroelectric La:HfO2 capacitors by a combination of Piezoresponse Force Microscopy (PFM) and pulse switching techniques to study the nanoscopic mechanism of polarization reversal and the wake-up process. It has been directly shown that the main mechanism behind the transformation of the polarization hysteretic behavior and an increase in the remanent polarization value upon the alternating current cycling is electrically induced domain de-pinning. PFM imaging and local spectroscopy revealed asymmetric switching in the La:HfO2 capacitors due to a significant imprint likely caused by the different boundary conditions at the top and bottom interfaces. Domain switching kinetics can be well-described by the nucleation limited switching model characterized by a broad distribution of the local switching times. It has been found that the domain velocity varies significantly throughout the switching process indicating strong interaction with structural defects.

  5. Electronic structure and magnetic properties of Ni-doped SnO2 thin films

    Science.gov (United States)

    Sharma, Mayuri; Kumar, Shalendra; Alvi, P. A.

    2018-05-01

    This paper reports the electronic structure and magnetic properties of Ni-doped SnO2 thin film which were grown on Si (100) substrate by PLD (pulse laser deposition) technique under oxygen partial pressure (PO2). For getting electronic structure and magnetic behavior, the films were characterized using near edge X-ray absorption fine structure spectroscopy (NEXAFS) and DC magnetization measurements. The NEXAFS study at Ni L3,2 edge has been done to understand the local environment of Ni and Sn ions within SnO2 lattice. DC magnetization measurement shows that the saturation magnetization increases with the increase in substitution of Ni2+ ions in the system.

  6. Toxicity of inhaled 239PuO2 in Fischer 344 rats

    International Nuclear Information System (INIS)

    Redman, H.C.; Boecker, B.B.; Muggenburg, B.A.; Griffith, W.C.; Guilmette, R.A.; Mewhinney, J.A.; Scott, B.R.

    1979-01-01

    Studies on the biological effects of inhaled particles of 239 PuO 2 have been initiated in the Fischer 344 rat. To obtain information on the importance of homogeneity or nonhomogeneity of radiation dose to the lung, young adult (84 +- 7 days) animals have been exposed to monodisperse aerosols (sigma/sub g/ 239 PuO 2 of 1.0 and 2.8 μm aerodynamic diameter (AD). To determine the effects of age at exposure, aged rats (600 to 660 days) have been exposed to monodisperse aerosols of 239 PuO 2 of 1.0 μm aerodynamic diameter. To date, 480 young adult rats have been exposed to 239 PuO 2 : 240 rats to 1.0 μm AD particles and 240 rats to 2.85 μm AD particles. The projected exposure level ranged from 0.012 to 0.115 μCi/kg body weight. One hundred sixty rats were sham-exposed and maintained as controls. Also, 240 aged rats have been exposed to date to 1.0 μm AD particles of 239 PuO 2 . The projected activity level ranged from 0.012 to 0.115 μCi/kg body weight. Eighty rats were sham-exposed and maintained as controls. In addition, a serial sacrifice study to determine radiation-dose pattern in rats resulting from the inhalation of these monodisperse aerosols of 239 PuO 2 has been initiated in the young adult rat

  7. X-ray photoelectron spectra structure and chemical bonding in AmO2

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2015-01-01

    Full Text Available Quantitative analysis was done of the X-ray photoelectron spectra structure in the binding energy range of 0 eV to ~35 eV for americium dioxide (AmO2 valence electrons. The binding energies and structure of the core electronic shells (~35 eV-1250 eV, as well as the relativistic discrete variation calculation results for the Am63O216 and AmO8 (D4h cluster reflecting Am close environment in AmO2 were taken into account. The experimental data show that the many-body effects and the multiplet splitting contribute to the spectral structure much less than the effects of formation of the outer (0-~15 eV binding energy and the inner (~15 eV-~35 eV binding energy valence molecular orbitals. The filled Am 5f electronic states were shown to form in the AmO2 valence band. The Am 6p electrons participate in formation of both the inner and the outer valence molecular orbitals (bands. The filled Am 6p3/2 and the O 2s electronic shells were found to make the largest contributions to the formation of the inner valence molecular orbitals. Contributions of electrons from different molecular orbitals to the chemical bond in the AmO8 cluster were evaluated. Composition and sequence order of molecular orbitals in the binding energy range 0-~35 eV in AmO2 were established. The experimental and theoretical data allowed a quantitative scheme of molecular orbitals for AmO2, which is fundamental for both understanding the chemical bond nature in americium dioxide and the interpretation of other X-ray spectra of AmO2.

  8. Nuclear microscopy as a tool in TiO2 nanoparticles bioaccumulation studies in aquatic species

    Science.gov (United States)

    Pinheiro, Teresa; Moita, Liliana; Silva, Luís; Mendonça, Elsa; Picado, Ana

    2013-07-01

    Engineered Titanium nanoparticles are used for a wide range of applications from coatings, sunscreen cosmetic additives to solar cells or water treatment agents. Inevitably environmental exposure can be expected and data on the ecotoxicological evaluation of nanoparticles are still scarce. The potential effects of nanoparticles of titanium dioxide (TiO2) on two model organisms, the water flea, Daphnia magna and the duckweed Lemna minor, were examined in semichronic toxicity tests. Daphnia and Lemna were exposed to TiO2 nanoparticles (average particle size value of 28 ± 11 nm (n = 42); concentration range, 1.4-25 mg/L) by dietary route and growth in medium containing the nanoparticles of TiO2, respectively. Both morphology and microdistribution of Ti in the individuals were examined by nuclear microscopy techniques. A significant amount of TiO2 was found accumulated in Daphnia exposed to nanoparticles. Nuclear microscopy imaging revealed that Ti was localized only in the digestive tract of the Daphnia, which displayed difficulty in eliminating the nanoparticles from their body. Daphnia showed higher mortality when exposed to higher concentrations of TiO2 (>10 mg/L). The exposure to TiO2 nanoparticles above 25 mg/L caused morphological alterations in Lemna. The roots became stiff and fronds colorless. The Ti mapping of cross-sections of roots and fronds showed that Ti was mainly deposited in the epidermis of the fronds and roots, with minor internalization. In summary, exposure of aquatic organisms to TiO2 nanoparticles may alter the physiology of these organisms at individual and population levels, posing risks to aquatic ecosystems.

  9. Nuclear microscopy as a tool in TiO2 nanoparticles bioaccumulation studies in aquatic species

    International Nuclear Information System (INIS)

    Pinheiro, Teresa; Moita, Liliana; Silva, Luís; Mendonça, Elsa; Picado, Ana

    2013-01-01

    Engineered Titanium nanoparticles are used for a wide range of applications from coatings, sunscreen cosmetic additives to solar cells or water treatment agents. Inevitably environmental exposure can be expected and data on the ecotoxicological evaluation of nanoparticles are still scarce. The potential effects of nanoparticles of titanium dioxide (TiO 2 ) on two model organisms, the water flea, Daphnia magna and the duckweed Lemna minor, were examined in semichronic toxicity tests. Daphnia and Lemna were exposed to TiO 2 nanoparticles (average particle size value of 28 ± 11 nm (n = 42); concentration range, 1.4–25 mg/L) by dietary route and growth in medium containing the nanoparticles of TiO 2 , respectively. Both morphology and microdistribution of Ti in the individuals were examined by nuclear microscopy techniques. A significant amount of TiO 2 was found accumulated in Daphnia exposed to nanoparticles. Nuclear microscopy imaging revealed that Ti was localized only in the digestive tract of the Daphnia, which displayed difficulty in eliminating the nanoparticles from their body. Daphnia showed higher mortality when exposed to higher concentrations of TiO 2 (>10 mg/L). The exposure to TiO 2 nanoparticles above 25 mg/L caused morphological alterations in Lemna. The roots became stiff and fronds colorless. The Ti mapping of cross-sections of roots and fronds showed that Ti was mainly deposited in the epidermis of the fronds and roots, with minor internalization. In summary, exposure of aquatic organisms to TiO 2 nanoparticles may alter the physiology of these organisms at individual and population levels, posing risks to aquatic ecosystems

  10. Effect of TiO2 nano fillers on the electrical conductivity of PSAN/TiO2 polymer nanocomposites

    Science.gov (United States)

    Ningaraju, S.; Munirathnamma, L. M.; Kumar, K. V. Aneesh; Ravikumar, H. B.

    2016-05-01

    The microstructural characterization of Polystyrene co-acrylonitrile and Titanium dioxide (PSAN/TiO2) nanocomposites has been performed by Positron Annihilation Lifetime Spectroscopy. The decrease of positron lifetime parameters viz. o-Ps lifetime (τ3) and free volume size (Vf) up to 0.6 wt% of TiO2 is attributed to the filling of free volume holes by TiO2 nanoparticles. The increased free volume size (Vf) after 0.6 wt% of TiO2 indicates the formation of interface due to TiO2 nanoclusters. The variation of electrical conductivity at the lower and higher concentration of TiO2 in (PSAN/TiO2) nanocomposites is attributed to the blocking effect and space charge effect respectively.

  11. Difference in Thermal Degradation Behavior of ZrO2 and HfO2 Anodized Capacitors

    Science.gov (United States)

    Kamijyo, Masahiro; Onozuka, Tomotake; Yoshida, Naoto; Shinkai, Satoko; Sasaki, Katsutaka; Yamane, Misao; Abe, Yoshio

    2004-09-01

    Microcrystalline ZrO2 and HfO2 thin film capacitors were prepared by anodizing sputter-deposited Zr and Hf films. The thermal degradation behavior of both anodized capacitors was clarified by the measurement of their capacitance properties and Auger depth profiles before and after heat treatment in air. As a result, it is confirmed that the heat-resistance property of the HfO2 anodized capacitor is superior to that of the ZrO2 capacitor. In addition, it is revealed that the thermal degradation of the ZrO2 anodized capacitor is caused by the diffusion of Zr atoms from the underlying layer into the ZrO2 anodized layer, while that of the HfO2 anodized capacitor is caused by the diffusion of oxygen atoms from the anodized layer into the underlying Hf layer.

  12. Habituation/Fatigue behavior of a synapse memristor based on IGZO-HfO2 thin film.

    Science.gov (United States)

    Jiang, Ran; Ma, Pengfei; Han, Zuyin; Du, Xianghao

    2017-08-24

    A synaptic memristor based on IGZO and oxygen-deficient HfO 2 films has been demonstrated. The memristor exhibits a fatigue response to a monotonic stimulus of voltage pulses, which is analogous to the habituation behavior of biological memory. The occurrence of habituation is nearly simultaneous with the transition from short-term memory to long-term memory. The movement and redistribution of oxygen species with the assistance of polarization in HfO 2 layer are responsible for the above results. The observation of habituation behavior proves the potential prospect of memristor on the mimic of biological neuron.

  13. Changes in the microbiological and chemical characteristics of white bread during storage in paper packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2.

    Science.gov (United States)

    Peter, Anca; Mihaly-Cozmuta, Leonard; Mihaly-Cozmuta, Anca; Nicula, Camelia; Ziemkowska, Wanda; Basiak, Dariusz; Danciu, Virginia; Vulpoi, Adriana; Baia, Lucian; Falup, Anca; Craciun, Grigore; Ciric, Alexandru; Begea, Mihaela; Kiss, Claudia; Vatuiu, Daniela

    2016-04-15

    Microbiological and chemical characteristics of white bread during storage in paper-packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2 were investigated. The whiteness and the water retention of the modified packages were slightly superior to those exhibited by the reference sample, as the color of the composite was lighter. The water retention was very good especially for the Ag/TiO2-SiO2-paper. These improvements can be associated with the high specific surface area and with the low agglomeration tendency of Ag nanoparticles in comparison with the Au ones. The preservation activity of the composites for the bread storage is positively influenced by photoactivity and presence of nano-Ag. Packages Ag/TiO2-SiO2-paper and Ag/N-TiO2-paper can find their applicability for extending the shelf life of bread by 2 days as compared with the unmodified paper-package. No influence of the Au/TiO2 on the extending the shelf life of bread was observed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Supramolecular photocatalyst of RGO-cyclodextrin-TiO2

    International Nuclear Information System (INIS)

    Shen, Jianfeng; Li, Na; Ye, Mingxin

    2013-01-01

    Graphical abstract: Supramolecular photocatalyst of RGO-cyclodextrin-TiO 2 was achieved, which showed high photocatalytic activity and adsorption capacity. Highlights: •Supramolecular photocatalyst of RGO-cyclodextrin-TiO 2 was achieved. •β-CD molecules acted as linkers between RGO and monodisperse TiO 2 nanoparticles. •Reduction of GO and preparation of RGO-cyclodextrin-TiO 2 was simultaneous. •The prepared RGO-cyclodextrin-TiO 2 shows high photocatalytic activity and adsorption capacity. -- Abstract: Reduced graphene oxide (RGO)/β-cyclodextrin (β-CD)/titanium oxide (TiO 2 ) supramolecular photocatalyst was synthesized with a one-pot hydrothermal method. The reducing process was accomplished with the attaching of β-CD and generation of TiO 2 . β-CD acted as a linker between RGO and monodisperse TiO 2 nanoparticles. The structure and composition of the hybrid had been characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, thermal gravimetric analysis, X-ray diffraction and Transmission electron microscopy. The as-prepared RGO-CD-TiO 2 showed significant enhanced performance for phenol and Cr (VI) removal, due to the effective transfer of photo-generated electron from TiO2 to RGO and improved absorbance performance of the hybrid

  15. Modulation of liver mitochondrial NOS is implicated in thyroid-dependent regulation of O(2) uptake.

    Science.gov (United States)

    Carreras, M C; Peralta, J G; Converso, D P; Finocchietto, P V; Rebagliati, I; Zaninovich, A A; Poderoso, J J

    2001-12-01

    Changes in O(2) uptake at different thyroid status have been explained on the basis of the modulation of mitochondrial enzymes and membrane biophysical properties. Regarding the nitric oxide (NO) effects, we tested whether liver mitochondrial nitric oxide synthase (mtNOS) participates in the modulation of O(2) uptake in thyroid disorders. Wistar rats were inoculated with 400 microCi (131)I (hypothyroid group), 20 microg thyroxine (T(4))/100 g body wt administered daily for 2 wk (hyperthyroid group) or vehicle (control). Basal metabolic rate, mitochondrial function, and mtNOS activity were analyzed. Systemic and liver mitochondrial O(2) uptake and cytochrome oxidase activity were lower in hypothyroid rats with respect to controls; mitochondrial parameters were further decreased by L-arginine (-42 and -34%, P activity (260%) were selectively increased in hypothyroidism and reverted by hormone replacement without changes in other nitric oxide isoforms. Moreover, mtNOS activity correlated with serum 3,5,3'-triiodothyronine (T(3)) and O(2) uptake. Increased mtNOS activity was also observed in skeletal muscle mitochondria from hypothyroid rats. Therefore, we suggest that modulation of mtNOS is a substantial part of thyroid effects on mitochondrial O(2) uptake.

  16. Application of UV/TiO2/H2O2 Advanced Oxidation to Remove Naphthalene from Water

    Directory of Open Access Journals (Sweden)

    Behroz Karimi

    2016-11-01

    Full Text Available Naphthalene is released into the environment by burning such organic materials as fossil fuels and wood and in industrial and vehicle exhaust emissions. Naphthalene is used in the manufacture of plastics, resins, fuels, and dyes. The aim of this study was to evaluate the performance of UV/TiO2/H2O2 process to decompose naphthalene in aqueous solutions. For this purpose, the photocatalytic degradation of naphthalene was investigated under UV light irradiation in the presence of TiO2 and H2O2 under a variety of conditions. Photodegradation efficiencies of H2O2/UV, TiO2/UV, and H2O2/TiO2/UV processes were compared in a batch reactor using the low pressure mercury lamp irradiation. The effects of operating parameters such as reaction time (min; solution pH; and initial naphthalene, TiO2, and H2O2 concentrations on photodegradation were examined. In the UV/TiO2/H2O2 system with a naphthalene concentration of 15 mg/L, naphthalene removal efficiencies of 63, 75, 80, 88, 92, 95, 96.5, and 98% were achieved, respectively, for reaction times of 5, 10, 20, 30, 40, 50, 60, 100 and 120 min. This is while removal efficienciesof 50, 59.5, 69, 80, 85, 88, 91, and 95% were obtained in the UV/TiO2 system under the same conditions. For initial pH values of 3, 4, 5, 6, 7,9, 10, and 12, naphthalene removal efficiencies of approximately 96.8, 85.5, 86, 75.5, 68.8, 57.8, and 52.5% were acheived, respectively, with the UV/TiO2/H2O2 system. Thus, it may be claiomed that, compared to either H2O2/UV or TiO2/UV process, the H2O2/TiO2/UV process yielded a far more efficient photodegradation.

  17. Foreign Body Retrieval

    Medline Plus

    Full Text Available ... bodies. top of page How does the procedure work? Your physician may use an x-ray or ... the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves ...

  18. Detection of movement artifact in recorded pulse oximeter saturation.

    Science.gov (United States)

    Poets, C F; Stebbens, V A

    1997-10-01

    Movement artifact (MA) must be detected when analysing recordings of pulse oximeter saturation (SpO2). Visual analysis of individual pulse waveforms is the safest, but also the most tedious, method for this purpose. We wanted to test the reliability of a computer algorithm (Edentec Motion Annotation System), based on a comparison between pulse and heart rate, for MA detection. Ten 12-h recordings of SpO2, pulse waveforms and heart rate from ten preterm infants were analysed for the presence of MA on the pulse waveform signal. These data were used to determine the sensitivity and specificity of the computer algorithm, and of the oximeter itself, in detecting MA. Recordings were divided into segments of 2.5 s duration to compare the movement identification methods. Of the segments 31% +/- 6% (mean +/- SD) contained MA. The computer algorithm identified 95% +/- 3% of these segments, the pulse oximeter only 18% +/- 11%. Specificity was 85% +/- 4% and 99% +/- 0%, respectively. SpO2 was signal showed MA during this time, leaving a significant potential for erroneous identification of hypoxaemia. Recordings of SpO2 do not allow a reliable identification of MA. Without additional information about movement artifact, a significant proportion of recording time of pulse oximeter signal may be regarded as demonstrating hypoxaemia which, in fact, simply reflects poor measurement conditions. The computer algorithm used in this study identified periods of movement artifact reliably.

  19. Absolute rate constants for the reaction of CF3O2 and CF3O radicals with NO at 295 K

    DEFF Research Database (Denmark)

    Sehested, J.; Nielsen, O.J.

    1993-01-01

    Using a pulse radiolysis UV absorption technique and subsequent simulations of experimental NO2 and FNO absorption transients, rate constants for reaction between CF3O and CF3O2 radicals with NO were determined, CF3O2+NO-->CF3O+NO2 (3), CF3O+NO-->CF2O+FNO (5). k3 was derived to be (1.68+/-0.26)x10...

  20. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes junction for dye sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Nguyen Huy Hao

    2016-08-01

    Full Text Available The dye sensitized solar cell (DSSC, which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.

  1. Electronic states of SiO2-MxOy (MxOy=P205, TiO2 and ZrO2) glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kowada, Y [Hyogo Univ. of Teacher Education, Hyogo (Japan); Adachi, H [Kyoto Univ. (Japan). Faculty of Engineering; Minami, T [Univ. of Osaka Prefecture, Osaka (Japan). Faculty of Engineering

    1993-12-01

    Using the sol-gel method the surface of metal and glass substrates can be modified. For example, stainless steel sheets coated with the SiO2-ZrO2 glass films have higher resistance to corrosion and oxidation. The coating films contain high concentration of alkali ions diffusing from the glass substrates. It suggests that the sodium ions are trapped strongly within the coating films and are blocked to further diffuse to the surface. This behavior must be associated with the chemical bonding around the sodium ions in the SiO2-TiO2 and SiO2-ZrO2 films. For better understanding of the chemical bonding in the glasses, the electronic states of the SiO2-MxOy glasses were calculated by means of the DV-Xa cluster method. In this paper, the calculation method is explained, the results are discussed and the conclusion is stated. 17 refs., 6 figs.

  2. Addition of IrO2 to RuO2+TiO2 coated anodes and its effect on electrochemical performance of anodes in acid media

    Directory of Open Access Journals (Sweden)

    Farhad Moradi

    2014-04-01

    Full Text Available Ternary mixed metal oxide coatings with the nominal composition IrxRu(0.6−xTi0.4O2 (x=0, 0.1, 0.2, 0.3 on the titanium substrate were prepared by thermal decomposition of a chloride precursor mixture. Surface morphology and microstructure of the coatings were investigated by Scanning electron microscopy (SEM, Field emission scanning electron microscopy (FE-SEM and X-ray diffraction (XRD analysis. Systematic study of electrochemical properties of these coatings was performed by cyclic voltammetry (CV and polarization measurements. The corrosion behavior of the coatings was evaluated under accelerated conditions (j=2 A cm−2 in acidic electrolyte. The role of iridium oxide admixture in the change of electrocatalytic activity and stability of Ru0.6Ti0.4O2 coating was discussed. Small addition of IrO2 can improve the stability of the RuO2+TiO2 mixed oxide, while the electrocatalytic activity for oxygen evolution reaction (OER is decreased. The shift of redox potentials for Ru0.6Ti0.4O2 electrode that is slightly activated with IrO2 and improvement in the stability can be attributed to the synergetic effect of mixed oxide formation.

  3. Pulse plating

    CERN Document Server

    Hansal, Wolfgang E G; Green, Todd; Leisner, Peter; Reichenbach, Andreas

    2012-01-01

    The electrodeposition of metals using pulsed current has achieved practical importance in recent years. Although it has long been known that changes in potential, with or without polarity reversal, can significantly affect the deposition process, the practical application of this has been slow to be adopted. This can largely be explained in terms of the complex relationship between the current regime and its effect on the electrodeposition process. In order to harness these effects, an understanding of the anodic and cathodic electrochemical processes is necessary, together with the effects of polarity reversal and the rate of such reversals. In this new monograph, the basics of metal electrodeposition from solution are laid out in great detail in seven distinct chapters. With this knowledge, the reader is able to predict how a given pulse train profile can be adopted to achieve a desired outcome. Equally important is the choice of a suitable rectifier and the ancillary control circuits to enable pulse platin...

  4. Vibrational spectroscopy of shock-compressed fluid N2 and O2

    International Nuclear Information System (INIS)

    Schmidt, S.C.; Moore, D.S.; Shaw, M.S.; Johnson, J.D.

    1987-01-01

    Single-pulse multiplex coherent anti-Stokes Raman scattering (CARS) was used to observe the vibrational spectra of liquid N 2 shock-compressed to several pressures and temperatures up to 41 GPa and 5200 K and liquid O 2 shock-compressed to several pressures and temperatures up to 10 GPa and 1000 K. For N 2 , the experimental spectra were compared to synthetic spectra calculated using a semiclassical model for CARS intensities and estimated vibrational frequencies, peak Raman susceptibilities, and Raman line widths. The question of excited state populations in the shock-compressed state is addressed

  5. Structural study of TiO2-based transparent conducting films

    International Nuclear Information System (INIS)

    Hitosugi, T.; Yamada, N.; Nakao, S.; Hatabayashi, K.; Shimada, T.; Hasegawa, T.

    2008-01-01

    We have investigated microscopic structures of sputter and pulsed laser deposited (PLD) anatase Nb-doped TiO 2 transparent conducting films, and discuss what causes the degradation of resistivity in sputter-deposited films. Cross-sectional transmission electron microscope and polarized optical microscope images show inhomogeneous intragrain structures and small grains of ∼10 μm in sputter-deposited films. From comparison with PLD films, these results suggest that homogeneous film growth is the important factor to obtain highly conducting sputter-deposited film

  6. High refractive index modification of SiO2 created by femtosecond laser nanostructuring

    International Nuclear Information System (INIS)

    Barillot, T; Grojo, D; Gertsvolf, M; Rayner, D M; Corkum, P B; Lei, S

    2010-01-01

    By comparing simulations with experiment, we show that the effective refractive index of fused SiO 2 can be locally reduced by (1.8 ± 0.2)% by femtosecond laser nanostructuring. We create a microlens of material containing a planar array of nanocracks embedded inside fused silica and probe how it refracts or absorbs light as a function of pulse energy. The self-generated microlens lowers the peak light intensity by deflecting the light around the focus. We obtain the refractive index by simulating the beam transport using the 3D wave equation in conjunction with the measured dimensions of the modified material.

  7. Amorphous-crystalline transition in thermoelectric NbO2

    International Nuclear Information System (INIS)

    Music, Denis; Chen, Yen-Ting; Bliem, Pascal; Geyer, Richard W

    2015-01-01

    Density functional theory was employed to design enhanced amorphous NbO 2 thermoelectrics. The covalent-ionic nature of Nb–O bonding is identical in amorphous NbO 2 and its crystalline counterpart. However, the Anderson localisation occurs in amorphous NbO 2 , which may affect the transport properties. We calculate a multifold increase in the absolute Seebeck coefficient for the amorphous state. These predictions were critically appraised by measuring the Seebeck coefficient of sputtered amorphous and crystalline NbO 2 thin films with the identical short-range order. The first-order phase transition occurs at approximately 550 °C, but amorphous NbO 2 possesses enhanced transport properties at all temperatures. Amorphous NbO 2 , reaching  −173 μV K −1 , exhibits up to a 29% larger absolute Seebeck coefficient value, thereby validating the predictions. (paper)

  8. Preparation and Characterization of Fluorescent SiO2 Microspheres

    Science.gov (United States)

    Xu, Cui; Zhang, Hao; Guan, Ruifang

    2018-01-01

    Fluorescent compound without typical fluorophores was synthesized with citric acid (CA) and aminopropyltriethoxysilane (APTS) firstly, and then it was grafted to the surface of the prepared SiO2 microspheres by chemical reaction. The fluorescent SiO2 microspheres with good fluorescent properties were obtained by optimizing the reaction conditions. And the morphology and structure of the fluorescent SiO2 microspheres have been characterized by scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy. The results showed that the preparation of fluorescent SiO2 microspheres have good monodispersity and narrow particle size distribution. Moreover, the fluorescent SiO2 microspheres can be applied to detect Fe3+ in aqueous solution, prepare fluorescent SiO2 rubber, and have potential to be applied in the fluorescent labeling and fingerprint appearing technique fields.

  9. Preparations of high density (Th,U)O2 pellets

    International Nuclear Information System (INIS)

    Akabori, Mitsuo; Ikawa, Katsuichi

    1986-07-01

    Preparations of high density and homogeneous (Th,U)O 2 pellets by a powder metallurgy method were examined. (Th,U)O 2 powders were prepared by calcining coprecipitates of ammonium uranate and thorium hydroxide derived from nitrates and mixed sols, and by calcining mixed oxalates precipitated from nitrates. (Th,U)O 2 pellets were characterized with respect to sinterability, lattice parameter, microstructure, homogeneity and stoichiometry. Sintering atmospheres had a significant effect upon all the properties of the derived pellets. The sinterability of (Th,U)O 2 was most favourable in oxidizing and reducing atmospheres for ThO 2 -rich and UO 2 -rich compositions, respectively, and can be enhanced by presence of water vapour in sintering atmospheres. In addition, highly homogeneous (Th,U)O 2 pellets with 99 % in theoretical density were derived from the sol powders. (author)

  10. Sol-gel synthesis of TiO2-SiO2 photocatalyst for β-naphthol photodegradation

    International Nuclear Information System (INIS)

    Qourzal, S.; Barka, N.; Tamimi, M.; Assabbane, A.; Nounah, A.; Ihlal, A.; Ait-Ichou, Y.

    2009-01-01

    Silica gel supported titanium dioxide particles (TiO 2 -SiO 2 ) prepared by sol-gel method was as photocatalyst in the degradation of β-naphthol in water under UV-illumination. The prepared sample has been characterized by powder X-ray diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM). The supported catalyst had large surface area and good sedimentation ability. The photodegradation rate of β-naphthol under UV-irradiation depended strongly on adsorption capacity of the catalyst, and the photoactivity of the supported catalyst was much higher than that of the pure titanium dioxides. The experiments were measured by high performance liquid chromatography (HPLC). The photodegradation rate of β-naphthol using 60% TiO 2 -SiO 2 particles was faster than that using TiO 2 'Degussa P-25', TiO 2 'PC-50' and TiO 2 'Aldrich' as photocatalyst by 2.7, 4 and 7.8 times, respectively. The kinetics of photocatalytic β-naphthol degradation was found to follow a pseudo-first-order rate law. The effect of the TiO 2 loading on the photoactivity of TiO 2 -SiO 2 particles was also discussed. With good photocatalytic activity under UV-irradiation and the ability to be readily separated from the reaction system, this novel kind of catalyst exhibited the potential effective in the treatment of organic pollutants in aqueous systems.

  11. Microspheres of UO2, ThO2 and PuO2 for the high temperature reactor

    International Nuclear Information System (INIS)

    Brandau, E.

    2002-01-01

    The production of high temperature reactor fuel, so called pebble fuel, was done in the eighties by a special vibrational dropping process to obtain as sintered UO 2 - or ThO 2 -microspheres, so called 'Kernels', with a diameter size of about 300 μm. These microspheres have been coated and embedded in carbon balls to get the pebble fuel. Since the early nineties BRACE is developing the processings of microspheres starting with sols and suspensions to produce Al 2 O 3 , ZrO 2 , HfO 2 and Actinide oxide microspheres. Two main developments have been made: 1) the preparation of the feed solution (sol, suspension) and the solidification processing, and 2) the equipment, design, and electronic control have been completely changed. A newly developed suspension process for actinide oxides and for metal oxides e.g. Al 2 O 3 , TiO 2 , SiO 2 , ZrO 2 , HfO 2 , CeO 2 , ThO 2 , UO 2 , PuO 2 leads to cheaper production of as sintered microspheres. The processing and the installations will be described and the experience of production will be shown. (author)

  12. Decreased arterial PO2, not O2 content, increases blood flow through intrapulmonary arteriovenous anastomoses at rest.

    Science.gov (United States)

    Duke, Joseph W; Davis, James T; Ryan, Benjamin J; Elliott, Jonathan E; Beasley, Kara M; Hawn, Jerold A; Byrnes, William C; Lovering, Andrew T

    2016-09-01

    was measured at the end of each condition and QIPAVA was assessed using transthoracic saline contrast echocardiography. [Hb] was reduced from 14.2 ± 0.8 to 12.8 ± 0.7 g dl(-1) (10 ± 2% reduction) from CON to Low [Hb] conditions. PaO2 was no different between CON and Low [Hb], although CaO2 was 10.4%, 9.2% and 9.8% lower at 18%, 14% and 12.5% O2 , respectively. QIPAVA significantly increased as PaO2 decreased and, despite reduced CaO2, was similar at iso-PaO2. These data suggest that, with alveolar hypoxia, low PaO2 causes the hypoxia-induced increase in QIPAVA . Whether the low PO2 is detected at the carotid body, airway and/or the vasculature remains unknown. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

  13. Low-temperature preparation of rutile-type TiO2 thin films for optical coatings by aluminum doping

    Science.gov (United States)

    Ishii, Akihiro; Kobayashi, Kosei; Oikawa, Itaru; Kamegawa, Atsunori; Imura, Masaaki; Kanai, Toshimasa; Takamura, Hitoshi

    2017-08-01

    A rutile-type TiO2 thin film with a high refractive index (n), a low extinction coefficient (k) and small surface roughness (Ra) is required for use in a variety of optical coatings to improve the controllability of the reflection spectrum. In this study, Al-doped TiO2 thin films were prepared by pulsed laser deposition, and the effects of Al doping on their phases, optical properties, surface roughness and nanoscale microstructure, including Al distribution, were investigated. By doping 5 and 10 mol%Al, rutile-type TiO2 was successfully prepared under a PO2 of 0.5 Pa at 350-600 °C. The nanoscale phase separation in the Al-doped TiO2 thin films plays an important role in the formation of the rutile phase. The 10 mol%Al-doped rutile-type TiO2 thin film deposited at 350 °C showed excellent optical properties of n ≈ 3.05, k ≈ 0.01 (at λ = 400 nm) and negligible surface roughness, at Ra ≈ 0.8 nm. The advantages of the superior optical properties and small surface roughness of the 10 mol%Al-doped TiO2 thin film were confirmed by fabricating a ten-layered dielectric mirror.

  14. Effects of Cr-N-ZrO 2 seed layer formed on glass substrates for longitudinal recording media

    Science.gov (United States)

    Suzuki, Hiroyuki; Djayaprawira, David D.; Takahashi, Yoshio; Ishikawa, Akira; Ono, Toshinori; Yahisa, Yotsuo

    1999-03-01

    Effects of Cr-N-ZrO 2 seed layer deposited on glass substrates before the deposition of C/Co-Cr-Pt/Cr-Ti layers for longitudinal recording media have been investigated. The product of v and Is, the activation volume and the saturation magnetization per unit volume, media noise Nd and S0/ Nd, which is the half value of peak-to-peak output voltage of an isolated pulse over Nd at 11.8 kFC/mm, are evaluated. We find that vIs is decreased by adding N and ZrO 2 to Cr seed layer. Nd is reduced as vIs decreases by adding nitrogen to the Cr seed layer. This is mainly due to the decreased grain sizes of both Cr-Ti underlayer and Co-Cr-Pt magnetic layer. The Nd is further reduced by the addition of ZrO 2 to the Cr-N seed layer. Highest S0/ Nd is achieved for the media with Cr-N-ZrO 2 seed layer. On the other hand, the media with Cr-ZrO 2 seed layer deposited without nitrogen show the higher Nd. Therefore the decrease of the grain size by addition of nitrogen into Ar is essential to reduce Nd, and the ZrO 2 addition to the Cr-N seed layer seems to enhance the effect of grain size reduction by nitrogen addition.

  15. Catalytic Oxidation of NO over MnOx–CeO2 and MnOx–TiO2 Catalysts

    Directory of Open Access Journals (Sweden)

    Xiaolan Zeng

    2016-11-01

    Full Text Available A series of MnOx–CeO2 and MnOx–TiO2 catalysts were prepared by a homogeneous precipitation method and their catalytic activities for the NO oxidation in the absence or presence of SO2 were evaluated. Results show that the optimal molar ratio of Mn/Ce and Mn/Ti are 0.7 and 0.5, respectively. The MnOx–CeO2 catalyst exhibits higher catalytic activity and better resistance to SO2 poisoning than the MnOx–TiO2 catalyst. On the basis of Brunauer–Emmett–Teller (BET, X-ray diffraction (XRD, and scanning transmission electron microscope with mapping (STEM-mapping analyses, it is seen that the MnOx–CeO2 catalyst possesses higher BET surface area and better dispersion of MnOx over the catalyst than MnOx–TiO2 catalyst. X-ray photoelectron spectroscopy (XPS measurements reveal that MnOx–CeO2 catalyst provides the abundance of Mn3+ and more surface adsorbed oxygen, and SO2 might be preferentially adsorbed to the surface of CeO2 to form sulfate species, which provides a protection of MnOx active sites from being poisoned. In contrast, MnOx active sites over the MnOx–TiO2 catalyst are easily and quickly sulfated, leading to rapid deactivation of the catalyst for NO oxidation. Furthermore, temperature programmed desorption with NO and O2 (NO + O2-TPD and in situ diffuse reflectance infrared transform spectroscopy (in situ DRIFTS characterizations results show that the MnOx–CeO2 catalyst displays much stronger ability to adsorb NOx than the MnOx–TiO2 catalyst, especially after SO2 poisoning.

  16. Synthesis and physico-chemical characterization of CeO2/ZrO2-SO42- mixed oxides

    International Nuclear Information System (INIS)

    Hernandez E, J. M.; Silva R, R.; Garcia A, R.; Garcia S, L. A.; Handy, B. E.; Cardenas G, G.; Cueto H, A.

    2012-01-01

    Environmentally friendly solid-acid catalysts CeO 2 /ZrO 2 -SO 4 2- were prepared by the sol gel method varying CeO 2 content (10, 20 and 30 wt %) and using sulfation in situ, maintaining the sulfate ions amount present in the materials at 20 wt %. ZrO 2 and ZrO 2 -SO 4 2- were also prepared for comparison proposes using the same synthesis method. The materials were characterized by X-ray diffraction, nitrogen physisorption, potentiometric titration with n-butylamine, decomposition of 2-propanol and n-pentane isomerization. The specific surface area of ZrO 2 -SO 4 2- was high (160 m 2 /g) compared with the unmodified ZrO 2 (80 m 2 /g), however this area decreased with increasing the CeO 2 content (37-100 m 2 /g). There was no significant effect of CeO 2 on the tetragonal structure of ZrO 2 -SO 4 2- . The variation of acid sites amount runs parallel to the change of specific surface area. The acid sites amount decreased with increasing cerium oxide content. The decomposition of 2-propanol results fundamentally in the formation of dehydration products such as propylene and diisopropyl ether, both involving acid sites. In addition, a good performance during the n-pentane isomerization was observed for these materials. The selectivity towards isopentane reaches 84% when the Pt/CeO 2 /ZrO 2 -SO 4 2- catalyst with the highest CeO 2 content was used. (Author)

  17. Two-photon absorption laser-induced fluorescence of atomic oxygen in the afterglow of pulsed positive corona discharge

    Science.gov (United States)

    Ono, Ryo; Takezawa, Kei; Oda, Tetsuji

    2009-08-01

    Atomic oxygen is measured in the afterglow of pulsed positive corona discharge using time-resolved two-photon absorption laser-induced fluorescence. The discharge occurs in a 14 mm point-to-plane gap in dry air. After the discharge pulse, the atomic oxygen density decreases at a rate of 5×104 s-1. Simultaneously, ozone density increases at almost the same rate, where the ozone density is measured using laser absorption method. This agreement between the increasing rate of atomic oxygen and decreasing rate of ozone proves that ozone is mainly produced by the well-known three-body reaction, O+O2+M→O3+M. No other process for ozone production such as O2(v)+O2→O3+O is observed. The spatial distribution of atomic oxygen density is in agreement with that of the secondary streamer luminous intensity. This agreement indicates that atomic oxygen is mainly produced in the secondary streamer channels, not in the primary streamer channels.

  18. [The source and factors that influence tracheal pulse oximetry signal].

    Science.gov (United States)

    Fan, Xiao-hua; Wei, Wei; Wang, Jian; Mu, Ling; Wang, Li

    2010-03-01

    To investigate the source and factors that influence tracheal pulse oximetry signal. The adult mongrel dog was intubated after anesthesia. The tracheal tube was modified by attaching a disposable pediatric pulse oximeter to the cuff. The chest of the dog was cut open and a red light from the tracheal oximeter was aligned with the deeper artery. The changes in tracheal pulse oxygen saturation (SptO2) signal were observed after the deeper artery was blocked temporarily. The photoplethysmography (PPG) and readings were recorded at different intracuff pressures. The influence of mechanical ventilation on the signal was also tested and compared with pulse oxygen saturation (SpO2). The SptO2 signal disappeared after deeper artery was blocked. The SptO2 signal changed with different intracuff pressures (P signal appeared under 20-60 cm H2O of intracuff pressure than under 0-10 cm H2O of intracuff pressure(P signal under a condition with mechanical ventilation differed from that without mechanical ventilation (P signal is primarily derived from deeper arteries around the trachea, not from the tracheal wall. Both intracuff pressures and mechanical ventilation can influence SptO2 signal. The SptO2 signal under 20-60 cm H2O of intracuff pressure is stronger than that under 0-10 em H2O of intracuff pressure. Mechanical ventilation mainly changes PPG.

  19. Cerebral desaturation during exercise reversed by O2 supplementation

    DEFF Research Database (Denmark)

    Nielsen, H B; Boushel, Robert Christopher; Madsen, P

    1999-01-01

    microM) and DeltaHbO2 (-12 +/- 3 microM) were similar to those established without O2 supplementation, work capacity increased from 389 +/- 11 to 413 +/- 10 W (P cerebral......The combined effects of hyperventilation and arterial desaturation on cerebral oxygenation (ScO2) were determined using near-infrared spectroscopy. Eleven competitive oarsmen were evaluated during a 6-min maximal ergometer row. The study was randomized in a double-blind fashion with an inspired O2...

  20. The Dangers of Estimating V˙O2max Using Linear, Nonexercise Prediction Models.

    Science.gov (United States)

    Nevill, Alan M; Cooke, Carlton B

    2017-05-01

    This study aimed to compare the accuracy and goodness of fit of two competing models (linear vs allometric) when estimating V˙O2max (mL·kg·min) using nonexercise prediction models. The two competing models were fitted to the V˙O2max (mL·kg·min) data taken from two previously published studies. Study 1 (the Allied Dunbar National Fitness Survey) recruited 1732 randomly selected healthy participants, 16 yr and older, from 30 English parliamentary constituencies. Estimates of V˙O2max were obtained using a progressive incremental test on a motorized treadmill. In study 2, maximal oxygen uptake was measured directly during a fatigue limited treadmill test in older men (n = 152) and women (n = 146) 55 to 86 yr old. In both studies, the quality of fit associated with estimating V˙O2max (mL·kg·min) was superior using allometric rather than linear (additive) models based on all criteria (R, maximum log-likelihood, and Akaike information criteria). Results suggest that linear models will systematically overestimate V˙O2max for participants in their 20s and underestimate V˙O2max for participants in their 60s and older. The residuals saved from the linear models were neither normally distributed nor independent of the predicted values nor age. This will probably explain the absence of a key quadratic age term in the linear models, crucially identified using allometric models. Not only does the curvilinear age decline within an exponential function follow a more realistic age decline (the right-hand side of a bell-shaped curve), but the allometric models identified either a stature-to-body mass ratio (study 1) or a fat-free mass-to-body mass ratio (study 2), both associated with leanness when estimating V˙O2max. Adopting allometric models will provide more accurate predictions of V˙O2max (mL·kg·min) using plausible, biologically sound, and interpretable models.

  1. Thermal behavior of the amorphous precursors of the ZrO2-SnO2 system

    International Nuclear Information System (INIS)

    Stefanic, Goran; Music, Svetozar; Ivanda, Mile

    2008-01-01

    Thermal behavior of the amorphous precursors of the ZrO 2 -SnO 2 system on the ZrO 2 -rich side of the concentration range, prepared by co-precipitation from aqueous solutions of the corresponding salts, was monitored using differential thermal analysis, X-ray powder diffraction, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometry (EDS). The crystallization temperature of the amorphous precursors increased with an increase in the SnO 2 content, from 405 deg. C (0 mol% SnO 2 ) to 500 deg. C (40 mol% SnO 2 ). Maximum solubility of Sn 4+ ions in the ZrO 2 lattice (∼25 mol%) occurred in the metastable products obtained upon crystallization of the amorphous precursors. A precise determination of unit-cell parameters, using both Rietveld and Le Bail refinements of the powder diffraction patterns, shows that the incorporation of Sn 4+ ions causes an asymmetric distortion of the monoclinic ZrO 2 lattice. The results of phase analysis indicate that the incorporation of Sn 4+ ions has no influence on the stabilization of cubic ZrO 2 and negligible influence on the stabilization of tetragonal ZrO 2 . Partial stabilization of tetragonal ZrO 2 in products having a tin content above its solid-solubility limit was attributed to the influence of ZrO 2 -SnO 2 surface interactions. In addition to phases closely structurally related to cassiterite, monoclinic ZrO 2 and tetragonal ZrO 2 , a small amount of metastable ZrSnO 4 phase appeared in the crystallization products of samples with 40 and 50 mol% of SnO 2 calcined at 1000 deg. C. Further temperature treatments caused a decrease in and disappearance of metastable phases. The results of the micro-structural analysis show that the sinterability of the crystallization products significantly decreases with an increase in the SnO 2 content

  2. In-vitro model for evaluation of pulse oximetry

    Science.gov (United States)

    Vegfors, Magnus; Lindberg, Lars-Goeran; Lennmarken, Claes; Oberg, P. Ake

    1991-06-01

    An in vitro model with blood circulating in a silicon tubing system and including an artificial arterial bed is an important tool for evaluation of the pulse oximetry technique. The oxygen saturation was measured on an artificial finger using a pulse oximeter (SpO2) and on blood samples using a hemoximeter (SaO2). Measurements were performed at different blood flows and at different blood hematocrits. An increase in steady as well as in pulsatile blood flow was followed by an increase in pulse oximeter readings and a better agreement between SpO2 and SaO2 readings. After diluting the blood with normal saline (decreased hematocrit) the agreement was further improved. These results indicate that the pulse oximeter signal is related to blood hematocrit and the velocity of blood. The flow-related dependance of SpO2 was also evaluated in a human model. These results provided evidence that the pulse oximeter signal is dependent on vascular changes.

  3. Atmospheric chemistry of CF3C(O)O2 radicals. Kinetics of their reaction with NO2 and kinetics of the thermal decomposition of the product CF3C(O)O2NO2

    DEFF Research Database (Denmark)

    Wallington, T.J.; Sehested, J.; Nielsen, O.J.

    1994-01-01

    A pulse radiolysis technique has been used to measure a rate constant of (6.6 +/- 1.3) x 10(-12) cm3 molecule-1 s-1 for the association reaction between CF3C(O)O2 radicals and NO2 at 295 K and one atmosphere total pressure of SF6 diluent. A FTIR/smog chamber system was used to study the thermal...... decomposition CF3C(O)O2NO2. The rate of decomposition of CF3C(O)O2NO2 was independent of the total pressure of N2 diluent over the range 100-700 Torr and was fit by the expression k-1 = (1.9(-1.5)+7.6) x 10(16) exp[(-14000 +/- 480)/T] s-1. Implications for the atmospheric chemistry of CFC replacements...

  4. Synthesis of Nanocrystalline SnO2 Modified TiO2:a Material for Carbon Monoxide Gas Sensor

    Directory of Open Access Journals (Sweden)

    A. B. BODADE

    2008-11-01

    Full Text Available Nanocrystalline SnO2 doped TiO2 having average crystallite size of 45-50 nm were synthesized by the sol-gel method and studied for gas sensing behavior to reducing gases like CO, liquefied petroleum gas (LPG, NH3 and H2. The material characterization was done by using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR and scanning electron microscope (SEM. The sensitivity measurements were carried out as a function of different operating temperature in SnO2 doped TiO2. The 15 wt.% SnO2 doped TiO2 based CO sensor shows better sensitivity at an operating temperature 240°C Incorporation of 0.5 wt% Pd improved the sensitivity, selectivity, response time and reduced the operating temperature from 240°C to 200°C for CO sensor.

  5. In vitro cell culture pO2 is significantly different from incubator pO2.

    Science.gov (United States)

    Bambrick, L L; Kostov, Y; Rao, G

    2011-07-01

    Continuous noninvasive monitoring of peri-cellular liquid phase pO2 in adherent cultures is described. For neurons and astrocytes, this approach demonstrates that there is a significant difference between predicted and observed liquid phase pO2. Particularly at low gas phase pO2s, cell metabolism shifts liquid phase pO2 significantly lower than would be predicted from the O2 gas/air equilibrium coefficient, indicating that the cellular oxygen uptake rate exceeds the oxygen diffusion rate. The results demonstrate the need for direct pO2 measurements at the peri-cellular level, and question the widely adopted current practice of relying on setting the incubator gas phase level as means of controlling pericellular oxygen tension, particularly in static culture systems that are oxygen mass transfer limited. Copyright © 2011 American Institute of Chemical Engineers (AIChE).

  6. Bulk modulus of CeO2 and PrO2-An experimental and theoretical study

    International Nuclear Information System (INIS)

    Gerward, L.; Staun Olsen, J.; Petit, L.; Vaitheeswaran, G.; Kanchana, V.; Svane, A.

    2005-01-01

    The high-pressure structural behaviour of CeO 2 and PrO 2 has been investigated by synchrotron X-ray diffraction at pressures up to 20 and 35 GPa, respectively. The experiments are accompanied by first principles calculations using the self-interaction corrected local spin density (SIC-LSD) approximation. The experimental values for the zero-pressure bulk modulus of CeO 2 and PrO 2 are 220(9) and 187(8) GPa, respectively. Our calculations reproduce the lattice constants with good accuracy, but find identical bulk modulii for CeO 2 (176.9 GPa) and PrO 2 (176.8 GPa)

  7. Preliminary study in development of glass-ceramic based on SiO2-LiO2 system, starting of different SiO2 starting powders

    International Nuclear Information System (INIS)

    Daguano, J.K.M.F.; Santos, F.A.; Santos, C.; Marton, L.F.M.; Conte, R.A.; Rodrigues Junior, D.; Melo, F.C.L.

    2009-01-01

    In this work, lithium disilicate glass-ceramics were developed starting of the rice ash- SiO 2 and Li 2 CO 3 powders. The results were compared with glass ceramics based on the lithium disilicate obtained by commercial SiO 2 powders. Glass were melted at 1580 deg C, and annealed at 850 deg C. X-Ray diffraction and scanning electron microscopy were used for characterization of the materials, and hardness and fracture toughness were evaluated using Vickers indentation method. Glasses with amorphous structure were obtained in both materials. After annealing, 'rice-ash' samples presented Li 2 SiO 3 and residual SiO 2 as crystalline phases. On the other side, commercial SiO 2 - Samples presented only Li 2 Si 2 O 5 as crystalline phases and the better results of hardness and fracture toughness. (author)

  8. Optical properties of the Al2O3/SiO2 and Al2O3/HfO2/SiO2 antireflective coatings

    Science.gov (United States)

    Marszałek, Konstanty; Winkowski, Paweł; Jaglarz, Janusz

    2014-01-01

    Investigations of bilayer and trilayer Al2O3/SiO2 and Al2O3/HfO2/SiO2 antireflective coatings are presented in this paper. The oxide films were deposited on a heated quartz glass by e-gun evaporation in a vacuum of 5 × 10-3 [Pa] in the presence of oxygen. Depositions were performed at three different temperatures of the substrates: 100 °C, 200 °C and 300 °C. The coatings were deposited onto optical quartz glass (Corning HPFS). The thickness and deposition rate were controlled with Inficon XTC/2 thickness measuring system. Deposition rate was equal to 0.6 nm/s for Al2O3, 0.6 nm - 0.8 nm/s for HfO2 and 0.6 nm/s for SiO2. Simulations leading to optimization of the thin film thickness and the experimental results of optical measurements, which were carried out during and after the deposition process, have been presented. The optical thickness values, obtained from the measurements performed during the deposition process were as follows: 78 nm/78 nm for Al2O3/SiO2 and 78 nm/156 nm/78 nm for Al2O3/HfO2/SiO2. The results were then checked by ellipsometric technique. Reflectance of the films depended on the substrate temperature during the deposition process. Starting from 240 nm to the beginning of visible region, the average reflectance of the trilayer system was below 1 % and for the bilayer, minima of the reflectance were equal to 1.6 %, 1.15 % and 0.8 % for deposition temperatures of 100 °C, 200 °C and 300 °C, respectively.

  9. Quantitative Evidence for Lanthanide-Oxygen Orbital Mixing in CeO2, PrO2, and TbO2.

    Science.gov (United States)

    Minasian, Stefan G; Batista, Enrique R; Booth, Corwin H; Clark, David L; Keith, Jason M; Kozimor, Stosh A; Lukens, Wayne W; Martin, Richard L; Shuh, David K; Stieber, S Chantal E; Tylisczcak, Tolek; Wen, Xiao-Dong

    2017-12-13

    Understanding the nature of covalent (band-like) vs ionic (atomic-like) electrons in metal oxides continues to be at the forefront of research in the physical sciences. In particular, the development of a coherent and quantitative model of bonding and electronic structure for the lanthanide dioxides, LnO 2 (Ln = Ce, Pr, and Tb), has remained a considerable challenge for both experiment and theory. Herein, relative changes in mixing between the O 2p orbitals and the Ln 4f and 5d orbitals in LnO 2 are evaluated quantitatively using O K-edge X-ray absorption spectroscopy (XAS) obtained with a scanning transmission X-ray microscope and density functional theory (DFT) calculations. For each LnO 2 , the results reveal significant amounts of Ln 5d and O 2p mixing in the orbitals of t 2g (σ-bonding) and e g (π-bonding) symmetry. The remarkable agreement between experiment and theory also shows that significant mixing with the O 2p orbitals occurs in a band derived from the 4f orbitals of a 2u symmetry (σ-bonding) for each compound. However, a large increase in orbital mixing is observed for PrO 2 that is ascribed to a unique interaction derived from the 4f orbitals of t 1u symmetry (σ- and π-bonding). O K-edge XAS and DFT results are compared with complementary L 3 -edge and M 5,4 -edge XAS measurements and configuration interaction calculations, which shows that each spectroscopic approach provides evidence for ground state O 2p and Ln 4f orbital mixing despite inducing very different core-hole potentials in the final state.

  10. Effect of CeO2 and Y2O3 on microstructure, bioactivity and degradability of laser cladding CaO-SiO2 coating on titanium alloy.

    Science.gov (United States)

    Li, H C; Wang, D G; Chen, C Z; Weng, F

    2015-03-01

    To solve the lack of strength of bulk biomaterials for load-bearing applications and improve the bioactivity of titanium alloy (Ti-6Al-4V), CaO-SiO2 coatings on titanium alloy were fabricated by laser cladding technique. The effect of CeO2 and Y2O3 on microstructure and properties of laser cladding coating was analyzed. The cross-section microstructure of ceramic layer from top to bottom gradually changes from cellular-dendrite structure to compact cellular crystal. The addition of CeO2 or Y2O3 refines the microstructure of the ceramic layer in the upper and middle regions. The refining effect on the grain is related to the kinds of additives and their content. The coating is mainly composed of CaTiO3, CaO, α-Ca2(SiO4), SiO2 and TiO2. Y2O3 inhibits the formation of CaO. After soaking in simulated body fluid (SBF), the calcium phosphate layer is formed on the coating surface, indicating the coating has bioactivity. After soaking in Tris-HCl solution, the samples doped with CeO2 or Y2O3 present a lower weight loss, indicating the addition of CeO2 or Y2O3 improves the degradability of laser cladding sample. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Enhanced the hydrophobic surface and the photo-activity of TiO2-SiO2 composites

    Science.gov (United States)

    Wahyuni, S.; Prasetya, A. T.

    2017-02-01

    The aim of this research is to develop nanomaterials for coating applications. This research studied the effect of various TiO2-SiO2 composites in acrylic paint to enhance the hydrophobic properties of the substrate. Titanium dioxide containing silica in the range 20-35 mol% has been synthesized using sol-gel route. The XRD’s spectra show that increasing SiO2 content in the composite, decreasing its crystalline properties but increasing the surface area. TiO2-SiO2 composite was dispersed in acrylic paint in 2% composition by weight. The largest contact angle was 70, which produced by the substrate coated with TS-35-modified acrylic paint. This study also investigated the enhanced photo-activity of TiO2-SiO2 modified with poly-aniline. The XRD spectra show that the treatment does not change the crystal structure of TiO2. The photo-activity of the composite was evaluated by degradation of Rhodamine-B with visible light. The best performance of the degradation process was handled by the composite treated with 0.1mL anilines per gram of TiO2-SiO2 composite (TSP-A). On the other side, the contact angle 70 has not shown an excellent hydrophobic activity. However, the AFM spectra showed that nanoroughness has started to form on the surface of acrylic paint modified with TiO2-SiO2 than acrylic alone.

  12. Synthesis and characterization of a binary oxide ZrO2–TiO2 and its ...

    Indian Academy of Sciences (India)

    Administrator

    Synthesis and characterization of a binary oxide ZrO2–TiO2 and its application in ... Solar cells based on dye-sensitized TiO2 nanoparticles were first developed by Grätzel ... cells, resulting in high Jsc (short-circuit current density),. *Author for .... simple method to study dye sensitization of semiconduc- tors. It is found that the ...

  13. Relationship of bronchodilator response with oxygen pulse and ventilatory threshold in children with asthma: the effect of body composition and progressive aerobic activity in an environment with low humidity

    Directory of Open Access Journals (Sweden)

    Samera Puyan majd

    2015-11-01

    Full Text Available Background: Asthma is a leading cause of chronic illness in children, impacting heavily on their daily complications. The purpose of the present study was to relationship bronchodilator response (BDR with oxygen pulse (OP and ventilatory threshold (VT in asthma children with various body compositions during progressive aerobic activities. Material and Methods: 25 obese children (BMI>25 and %fat>30with asthma(10 subjects, and healthy children (15 subjects  and 25 lean children(BMI<20 and %fat<20 with asthma(13 subjects, and healthy children (7 subjects performed an exercise protocol in a constant temperature environment 2 ± 22 ° C and humidity (5 ± 35%. During exercise, the steady-state levels of cardio-respiratory parameters were measured using gas analyzer (K4B2. Results: The results showed that after a progressive aerobic activity, values peak oxygen consumption(vo2peak ​​, bronchodilator(BDR, oxygen pulse(OP and ventilatory threshold(VT  in lean and obese asthmatic children were lower than in healthy lean and obese children. In addition, lean children with asthma had lower VT and higher VO2peak , OP and BDR values​​, as compared obese asthmatic children. Between BDR and VT in lean and obese asthmatic children an inverse relationship between BDR and OP and a direct link to asthma in obese children and obese asthmatic children, there was a negative relationship non-significant. Conclusion: Compared with lean children, asthma, obesity as an additional load will affect lung function and increase the pressure on childhood asthma. Therefore, we can accept that obesity may limit performance of exercise in childhood asthma.

  14. pO2 measurements in arteriolar networks.

    Science.gov (United States)

    Torres Filho, I P; Kerger, H; Intaglietta, M

    1996-03-01

    Previous studies from our laboratory have shown that the average arteriolar pO2 in the hamster skinfold preparation is lower than arterial systemic pO2. In the present work we tested the hypothesis that there is a longitudinal gradient of pO2 along precapillary vessels. Experiments were performed in Syrian golden hamsters bearing a dorsal skin chamber. The oxygen-dependent quenching of phosphorescence of palladium-porphyrin complexes was used to measure intravascular pO2 in the microcirculation. Arterioles were classified in four orders according to their position in the network, first-order vessels being the entrance points. Simultaneous determinations of diameter (D), red blood cell velocity, and systemic blood gases were also made. There was a significant fall of pO2 between vessels of different orders. First-order arterioles (mean D = 64 microns) had pO2 of 51.8 +/- 9.8 mm Hg (mean +/- SD) which was equivalent to approximately equal to 73% of the arterial systemic pO2. Within the arteriolar network, further decreases of intravascular pO2 were measured, leading to a pO2 of 34.0 +/- 7.9 mm Hg in terminal arterioles (mean D = 7.7 microns). In some vessels pO2 was measured in different positions of the same arteriole. The average longitudinal arteriolar oxygen saturation gradient was 3.4 +/- 0.4 delta %/mm (range 0.8-7.2). A significant and positive correlation was found between pO2 and microhemodynamic parameters when arterioles were grouped according to their order. This relation was not significant for venules which showed a mean pO2 of 30.8 +/- 10.8 mm Hg. Tissue pO2 averaged 24.6 +/- 5.8 mm Hg. We conclude that: (1) There is an oxygen loss in arterial vessels larger than 100 micrograms in diameter, (2) arteriolar pO2 in this preparation depends on the position of the vessel within the network, (3) a substantial portion of oxygen delivery to the hamster skin is provided by the arteriolar network, and (4) only a small pO2 gradient exists between terminal

  15. Integration of atomic layer deposition CeO2 thin films with functional complex oxides and 3D patterns

    International Nuclear Information System (INIS)

    Coll, M.; Palau, A.; Gonzalez-Rosillo, J.C.; Gazquez, J.; Obradors, X.; Puig, T.

    2014-01-01

    We present a low-temperature, < 300 °C, ex-situ integration of atomic layer deposition (ALD) ultrathin CeO 2 layers (3 to 5 unit cells) with chemical solution deposited La 0.7 Sr 0.3 MnO 3 (LSMO) functional complex oxides for multilayer growth without jeopardizing the morphology, microstructure and physical properties of the functional oxide layer. We have also extended this procedure to pulsed laser deposited YBa 2 Cu 3 O 7 (YBCO) thin films. Scanning force microscopy, X-ray diffraction, aberration corrected scanning transmission electron microscopy and macroscopic magnetic measurements were used to evaluate the quality of the perovskite films before and after the ALD process. By means of microcontact printing and ALD we have prepared CeO 2 patterns using an ozone-robust photoresist that will avoid the use of hazardous lithography processes directly on the device components. These bilayers, CeO 2 /LSMO and CeO 2 /YBCO, are foreseen to have special interest for resistive switching phenomena in resistive random-access memory. - Highlights: • Integration of atomic layer deposition (ALD) CeO 2 layers on functional complex oxides • Resistive switching is identified in CeO 2 /La 0.7 Sr 0.3 MnO 3 and CeO 2 /YBa 2 Cu 3 O 7 bilayers. • Study of the robustness of organic polymers for area-selective ALD • Combination of ALD and micro-contact printing to obtain 3D patterns of CeO 2

  16. TiO2 coating promotes human mesenchymal stem cell proliferation without the loss of their capacity for chondrogenic differentiation

    International Nuclear Information System (INIS)

    Kaitainen, Salla; Lappalainen, Reijo; Mähönen, Anssi J; J Lammi, Mikko; Qu, Chengjuan; Kröger, Heikki

    2013-01-01

    Human mesenchymal stem cells (hMSCs) are used in applications, which may require a large amount of cells; therefore, efficient expansion of the cells is desired. We studied whether TiO 2 coating on plastic cell culture dishes could promote proliferation of hMSCs without adverse effects in chondrogenic differentiation. TiO 2 -films were deposited on polystyrene dishes and glass coverslips using an ultrashort pulsed laser deposition technique. Human MSCs from three donors were expanded on them until 95% confluence, and the cells were evaluated by morphology, immunocytochemistry and quantitative RT-PCR (qRT-PCR). The chondrogenic differentiation in pellets was performed after cultivation on TiO 2 -coated dishes. Chondrogenesis was evaluated by histological staining of proteoglycans and type II collagen, and qRT-PCR. Human MSC-associated markers STRO-1, CD44, CD90 and CD146 did not change after expansion on TiO 2 -coated coverslips. However, the cell number after a 48h-culture period was significantly higher on TiO 2 -coated culture dishes. Importantly, TiO 2 coating caused no significant differences in the proteoglycan and type II collagen staining of the pellets, or the expression of chondrocyte-specific genes in the chondrogenesis assay. Thus, the proliferation of hMSCs could be significantly increased when cultured on TiO 2 -coated dishes without weakening their chondrogenic differentiation capacity. The transparency of TiO 2 -films allows easy monitoring of the cell growth and morphology under a phase-contrast microscope. (paper)

  17. Synthesis of ZrO2-8%CeO2 and ZrO2-8%Y2O3 by polymeric precursors route

    International Nuclear Information System (INIS)

    Macedo, D.A.; Macedo, M.C.; Melo, D.M.A.; Nascimento, R.M.; Rabelo, A.A.

    2006-01-01

    The stabilization of zirconia in the cubical and tetragonal structures comes gaining importance because of its excellent thermal stability, chemical resistance, mechanical properties and oxygen conductivity. Its main applications include electrolytes of high temperature fuel cells, sensors of oxygen and electrochemical reactors. In this work the polymeric precursors route was used to synthesize ZrO 2 -8 mol% Y 2 O 3 and ZrO 2 -8 mol%CeO 2 . In this process the dopant concentration, besides making possible the stabilization of distinct structures, influences in the morphologic characteristics of the powders synthesized. The characterization of the powders was carried through X-ray diffraction for existing phases verification and average crystallite size, thermogravimetric analysis, specific surface area measures, particles size distribution by laser scattering and the powder morphology was observed using scanning electronic microscopy. The powder only calcined at 700 deg C had presented of average crystallite size of 6,77 nm for ZrO 2 -8%Y 2 O 3 and 7,14 nm for ZrO 2 -CeO 2 . (author)

  18. Potential energy landscape of an interstitial O2 molecule in a SiO2 film near the SiO2/Si(001) interface

    Science.gov (United States)

    Ohta, Hiromichi; Watanabe, Takanobu; Ohdomari, Iwao

    2008-10-01

    Potential energy distribution of interstitial O2 molecule in the vicinity of SiO2/Si(001) interface is investigated by means of classical molecular simulation. A 4-nm-thick SiO2 film model is built by oxidizing a Si(001) substrate, and the potential energy of an O2 molecule is calculated at Cartesian grid points with an interval of 0.05 nm in the SiO2 film region. The result shows that the potential energy of the interstitial site gradually rises with approaching the interface. The potential gradient is localized in the region within about 1 nm from the interface, which coincides with the experimental thickness of the interfacial strained layer. The potential energy is increased by about 0.62 eV at the SiO2/Si interface. The result agrees with a recently proposed kinetic model for dry oxidation of silicon [Phys. Rev. Lett. 96, 196102 (2006)], which argues that the oxidation rate is fully limited by the oxidant diffusion.

  19. TiO2, SiO2 and ZrO2 Nanoparticles Synergistically Provoke Cellular Oxidative Damage in Freshwater Microalgae

    Directory of Open Access Journals (Sweden)

    Yinghan Liu

    2018-02-01

    Full Text Available Metal-based nanoparticles (NPs are the most widely used engineered nanomaterials. The individual toxicities of metal-based NPs have been plentifully studied. However, the mixture toxicity of multiple NP systems (n ≥ 3 remains much less understood. Herein, the toxicity of titanium dioxide (TiO2 nanoparticles (NPs, silicon dioxide (SiO2 NPs and zirconium dioxide (ZrO2 NPs to unicellular freshwater algae Scenedesmus obliquus was investigated individually and in binary and ternary combination. Results show that the ternary combination systems of TiO2, SiO2 and ZrO2 NPs at a mixture concentration of 1 mg/L significantly enhanced mitochondrial membrane potential and intracellular reactive oxygen species level in the algae. Moreover, the ternary NP systems remarkably increased the activity of the antioxidant defense enzymes superoxide dismutase and catalase, together with an increase in lipid peroxidation products and small molecule metabolites. Furthermore, the observation of superficial structures of S. obliquus revealed obvious oxidative damage induced by the ternary mixtures. Taken together, the ternary NP systems exerted more severe oxidative stress in the algae than the individual and the binary NP systems. Thus, our findings highlight the importance of the assessment of the synergistic toxicity of multi-nanomaterial systems.

  20. Thermoluminescence induced by UV radiation in ZrO2-La2O3 and ZrO2-CeO2 mixed systems

    International Nuclear Information System (INIS)

    Estrada G, R.; Salas C, P.; Mendoza A, D.; Gonzalez, P.R.

    2002-01-01

    Nowadays, the development of catalytic materials by means of pure or mixed oxides mainly as TiO 2 , Al 2 O 3 , ZrO 2 , La 2 O 3 and CeO 2 used as support or active phases, are widely used in oxidation-reduction reactions in the chemical industry and in petroleum refining processes. the cerium and lanthanum oxides in zircon, have been studied recently in processes for reduction of pollutant gases (SO x , NO x , etc.). They result very interesting for resolving the problems of environmental pollution. Moreover, it has been observed that some of these materials are highly sensitive to ultraviolet radiation (UV), characteristic that can be took in advantage for detecting this type of radiation. In this work the preliminary obtained results on the thermoluminescent response (Tl) induced by the UV radiation in ZrO 2 -La 2 O 3 and ZrO 2 -CeO 2 mixed systems obtained by the sol-gel method are presented. The results show that the first system has a high sensitivity to UV radiation with a Tl curve composed by three peaks, two ones of greater intensity located in 70 and 140 Centigrade degrees. Likewise it was observed that for both materials, the peak located at low temperature is fadeout in few minutes after irradiation, while that the second one peak presented very good stability, resulting promising for dosimetric applications in UV radiation fields. (Author)

  1. H-TiO2/C/MnO2 nanocomposite materials for high-performance supercapacitors

    Science.gov (United States)

    Di, Jing; Fu, Xincui; Zheng, Huajun; Jia, Yi

    2015-06-01

    Functionalized TiO2 nanotube arrays with decoration of MnO2 nanoparticles (denoted as H-TiO2/C/MnO2) have been synthesized in the application of electrochemical capacitors. To improve both areal and gravimetric capacitance, hydrogen treatment and carbon coating process were conducted on TiO2 nanotube arrays. By scanning electron microscopy and X-ray photoelectron spectroscopy, it is confirmed that the nanostructure is formed by the uniform incorporation of MnO2 nanoparticles growing round the surface of the TiO2 nanotube arrays. Impedance analysis proves that the enhanced capacitive is due to the decrease of charge transfer resistance and diffusion resistance. Electrochemical measurements performed on this H-TiO2/C/MnO2 nanocomposite when used as an electrode material for an electrochemical pseudocapacitor presents quasi-rectangular shaped cyclic voltammetry curves up to 100 mV/s, with a large specific capacitance (SC) of 299.8 F g-1 at the current density of 0.5 A g-1 in 1 M Na2SO4 electrolyte. More importantly, the electrode also exhibits long-term cycling stability, only 13 % of SC loss after 2000 continuous charge-discharge cycles. Based on the concept of integrating active materials on highly ordered nanostructure framework, this method can be widely applied to the synthesis of high-performance electrode materials for energy storage.

  2. In vitro dose-response of macrophages to 239PuO2 and 241AmO2

    International Nuclear Information System (INIS)

    Schneider, R.P.; Robinson, A.V.

    1979-01-01

    As part of a study designed to examine various means of solubilizing actinide particles within macrophages, we have measured the in vitro effects of 241 AmO 2 and 239 PuO 2 on these cells. Dose distribution within the cell population was estimated by autoradiography and compared to cell detachment as a function of time. The 241 AmO 2 and 239 PuO 2 were toxic in proportion to their radioactivity rather than their mass. Approximately 385 intracellular disintegrations are required from either radionuclide to cause cells to detach from the flask surface

  3. A model for radiolysis of water and aqueous solutions of H2, H2O2 and O2

    International Nuclear Information System (INIS)

    Ershov, B.G.; Gordeev, A.V.

    2008-01-01

    Kinetic model for the radiolysis of pure water describing the formation of H 2 , H 2 O 2 and O 2 and the radiation chemical transformations of aqueous solutions containing these compounds over a broad range of concentrations, pH, absorbed doses and dose rates is proposed and substantiated. The model includes a set of chemical reactions with optimized rate constants and the radiation chemical yields of radiolysis products. The model applicability to the description of the whole set of data on the radiation chemical transformations of water and aqueous solutions of H 2 , H 2 O 2 and O 2 is demonstrated

  4. Fabrication of ThO2 and ThO2-UO2 pellets for proliferation resistant fuels

    International Nuclear Information System (INIS)

    Matthews, R.B.; Davis, N.C.

    1979-10-01

    To meet this objective, batches of ThO 2 powders were compared and milling parameters, pressing and sintering conditions were established. A method for blending ThO 2 and UO 2 into homogeneous powders that press and sinter into 95% TD pellets was determined. The effect of UO 2 additions on ThO 2 -UO 2 pellet properties was determined and a process for fabricating irradiation test quality ThO 2 -20 wt% UO 2 pellets containing CaO as a dissolution aid was established

  5. Effect of microdose distribution on chromosome aberration frequency in liver cells of the Chinese hamster following exposure to 239PuO2 or 238PuO2 particles

    International Nuclear Information System (INIS)

    Brooks, A.L.; Peters, R.F.; Retherford, J.C.

    1974-01-01

    Chinese hamsters were injected intravenously with 239 PuO 2 or 238 PuO 2 particles of known size or with 238 Pu citrate to determine the effect of particle size and specific activity on the frequency and distribution of chromosome damage in the liver. Three particle sizes were used in the 239 PuO 2 experiment: 0.15, 0.44, and 0.89 μm, and all animals were injected with a constant activity, 5 x 10 -4 muCi 239 Pu/gm body weight. The 238 PuO 2 was injected in three particle sizes, 0.17, 0.41, and 1.1 μm and at three activity levels. The 238 Pu citrate was injected at 5 x 10 -3 muCi 238 Pu/gm body weight. Hamsters injected with 239 PuO 2 were sacrificed at 15, 42, and 122 days after injection and those injected with either 238 PuO 2 or 238 Pu citrate were sacrificed 12 days after injection. The number of alpha tracks/star increased as a function of the particle size injected. A change in particle size with time was noted as smaller particles were aggregated into larger ones by the phagocytic action of Kupffer cells. Injection of 239 PuO 2 and 238 PuO 2 produced a distribution of chromosome damage which was non-poison in nature. 239 PuO 2 produced increased damage with increasing average dose with some cells containing a large number of aberrations, but there was relatively little particle size effect. Conversely, aberration frequencies after 238 PuO 2 injection were inversely related to particle size and no cells were seen with large amounts of damage. The 238 Pu citrate produced 6 x 10 -3 aberrations/cell/rad which was a higher rate than observed for 238 Pu particles. Risk for the production of cellular damage in the liver was greater per μCi following injection of either 238 Pu or 239 Pu citrate than it was following deposition of the same amount of 239 PuO 2 or 238 PuO 2 particles. (U.S.)

  6. Suppression of dewetting phenomena during excimer laser melting of thin metal films on SiO2

    International Nuclear Information System (INIS)

    Kline, J.E.; Leonard, J.P.

    2005-01-01

    Pulsed excimer laser irradiation has been used to fully melt 200 nm films of elemental Au and Ni on SiO 2 substrates. With the use of a capping layer of SiO 2 and line irradiation via projection optics, the typical liquid-phase dewetting processes associated with these metals on SiO 2 has been suppressed. In a series of experiments varying line widths and fluence, a process region is revealed immediately above the complete melting threshold for which the films remain continuous and smooth after melting and resolidification. Simple energetic arguments for mechanisms leading to initiation of dewetting support these observations, and a gas-mediated model is proposed to describe the process conditions that are necessary for the suppression of dewetting

  7. In Vivo pO2 Imaging of Tumors: Oxymetry with Very Low-Frequency Electron Paramagnetic Resonance.

    Science.gov (United States)

    Epel, Boris; Halpern, Howard J

    2015-01-01

    For over a century, it has been known that tumor hypoxia, regions of a tumor with low levels of oxygenation, are important contributors to tumor resistance to radiation therapy and failure of radiation treatment of cancer. Recently, using novel pulse electron paramagnetic resonance (EPR) oxygen imaging, near absolute images of the partial pressure of oxygen (pO2) in tumors of living animals have been obtained. We discuss here the means by which EPR signals can be obtained in living tissues and tumors. We review development of EPR methods to image the pO2 in tumors and the potential for the pO2 image acquisition in human subjects. © 2015 Elsevier Inc. All rights reserved.

  8. In vivo pO2 imaging of tumors: Oxymetry with very low frequency Electron Paramagnetic Resonance

    Science.gov (United States)

    Epel, Boris; Halpern, Howard J.

    2016-01-01

    For over a century it has been known that tumor hypoxia, regions of a tumor with low levels of oxygenation, are important contributors to tumor resistance to radiation therapy and failure of radiation treatment of cancer. Recently, using novel pulse electron paramagnetic resonance (EPR) oxygen imaging, near absolute images of the partial pressure of oxygen (pO2) in tumors of living animals have been obtained. We discuss here the means by which EPR signals can be obtained in living tissues and tumors. We review development of EPR methods to image the pO2 in tumors and the potential for the pO2 image acquisition in human subjects. PMID:26477263

  9. Distinction between SnO2 nanoparticles synthesized using co ...

    Indian Academy of Sciences (India)

    Administrator

    pared with that of a co-precipitation-modified SnO2 nanoparticles. Keywords. SnO2 nanoparticle ... Dye-sensitized solar cells (DSSCs), which convert light to electricity by means of ... nature, additives and aging time. Nanosized particles pre-.

  10. Impedance spectroscopy studies of surface engineered TiO2 ...

    Indian Academy of Sciences (India)

    Administrator

    Impedance; nanoTiO2; self-assembled monolayers; electrical resistivity; permittivity. 1. Introduction ... search studies showed that nanostructured TiO2 ceramics possess ..... tion handbook (ed) J Cazes (New York: Marcel Dekker). 3rd ed, p ...

  11. Silicon protected with atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Seger, Brian; Tilley, S. David; Pedersen, Thomas

    2013-01-01

    The present work demonstrates that tuning the donor density of protective TiO2 layers on a photocathode has dramatic consequences for electronic conduction through TiO2 with implications for the stabilization of oxidation-sensitive catalysts on the surface. Vacuum annealing at 400 °C for 1 hour o...

  12. Supercapacitive performance of hydrous ruthenium oxide (RuO2 ...

    Indian Academy of Sciences (India)

    2016-08-26

    SO4 electrolyte. RuO2.H2O film showed maximum specific capacitance of 192 F.g-1 at a scan rate of 20 mV.s-1. The charge–discharge studies of RuO2.H2O carried out at 300 A.cm-2 current density revealed the specific ...

  13. Facile hydrothermal synthesis of CeO2 nanopebbles

    Indian Academy of Sciences (India)

    Administrator

    However, to the best of our knowledge the reports on the synthesis of CeO2 ... The base pressure of the XAS chamber was in the range of 10–8 Pa. A Shimadzu ... scopy was investigated to confirm the crystalline quality of CeO2 nanopebbles.

  14. Synthesis of polyaniline/ZrO2 nanocomposites and their ...

    Indian Academy of Sciences (India)

    actions and nanoscale dimensions [9–11]. The morphology .... The reaction was allowed to proceed for 12 h. At the end of the reaction, PANI/ZrO2 composite formed was collected .... which is free to move along the chain, whereas the bound charges .... As men- tioned earlier, ZrO2 has the wide range of applications, which.

  15. Preparation, microstructures, and properties of PuO2

    International Nuclear Information System (INIS)

    Bickford, D.F.; Rankin, D.T.; Smith, P.K.

    1976-01-01

    PuO 2 pellets with controlled microstructures were fabricated to meet operational requirements for packaged heat sources. Size distributions, morphologies (forms and structures), and packing densities were measured on calcined and milled powders, slugged compacts, and presintered granules. These variables influence microstructure, porosity distribution, and fracture behavior of hot-pressed and sintered PuO 2

  16. Air to muscle O2 delivery during exercise at altitude

    DEFF Research Database (Denmark)

    Calbet, J.A.; Lundby, C.

    2009-01-01

    , diffusion limitation explains most of the additional Pao2-Pao2. With altitude, acclimatization exercise (Pao2-Pao2) is reduced, but does not reach the low values observed in high altitude natives, who possess an exceptionally high DLo2. Convective O2 transport depends on arterial O2 content (Cao2), cardiac...

  17. O2-GIDNC: Beyond instantly decodable network coding

    KAUST Repository

    Aboutorab, Neda; Sorour, Sameh; Sadeghi, Parastoo

    2013-01-01

    In this paper, we are concerned with extending the graph representation of generalized instantly decodable network coding (GIDNC) to a more general opportunistic network coding (ONC) scenario, referred to as order-2 GIDNC (O2-GIDNC). In the O2-GIDNC

  18. Improved Treatment of Photothermal Cancer by Coating TiO2 on Porous Silicon.

    Science.gov (United States)

    Na, Kil Ju; Park, Gye-Choon

    2016-02-01

    In present society, the technology in various field has been sharply developed and advanced. In medical technology, especially, photothermal therapy and photodynamic therapy have had limelight for curing cancers and diseases. The study investigates the photothermal therapy that reduces side effects of existing cancer treatment, is applied to only cancer cells, and dose not harm any other normal cells. The photothermal properties of porous silicon for therapy are analyzed in order to destroy cancer cells that are more weak at heat than normal ones. For improving performance of porous silicon, it also analyzes the properties when irradiating the near infrared by heterologously junction TiO2 and TiO2NW, photocatalysts that are very stable and harmless to the environment and the human body, to porous silicon. Each sample of Si, PSi, TiO2/Psi, and TiO2NW/PSi was irradiated with 808 nm near-IR of 300, 500, and 700 mW/cm2 light intensity, where the maximum heating temperature was 43.8, 61.6, 67.9, and 61.9 degrees C at 300 mW/cm2; 54.1, 64.3, 78.8, and 68.9 degrees C at 500 mW/cm2; and 97.3, 102.8, 102.5, and 95 0C at 700 mW/cm2. The time required to reach the maximum temperature was less than 10 min for every case. The results indicate that TiO2/PSi thin film irradiated with a single near-infrared wavelength of 808 nm, which is known to have the best human permeability, offers the potential of being the most successful photothermal cancer therapy agent. It maximizes the photo-thermal characteristics within the shortest time, and minimizes the adverse effects on the human body.

  19. TiO2 brookite nanostructured thin layer on magneto-optical surface plasmon resonance transductor for gas sensing applications

    Science.gov (United States)

    Manera, M. G.; Colombelli, A.; Rella, R.; Caricato, A.; Cozzoli, P. D.; Martino, M.; Vasanelli, L.

    2012-09-01

    The sensing performance comparisons presented in this work were carried out by exploiting a suitable magneto-plasmonic sensor in both the traditional surface plasmon resonance configuration and the innovative magneto-optic surface plasmon resonance one. The particular multilayer transducer was functionalized with TiO2 Brookite nanorods layers deposited by matrix assisted pulsed laser evaporation, and its sensing capabilities were monitored in a controlled atmosphere towards different concentrations of volatile organic compounds mixed in dry air.

  20. Study of Pt–Rh/CeO2–ZrO2–MxOy (M = Y, La)/Al2O3 three-way catalysts

    International Nuclear Information System (INIS)

    Jiaxiu, Guo; Zhonghua, Shi; Dongdong, Wu; Huaqiang, Yin; Maochu, Gong; Yaoqiang, Chen

    2013-01-01

    CeO 2 –ZrO 2 –M x O y (M = Y; La) mixed oxides, prepared by co-precipitation method and characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Raman spectra (RM) and oxygen pulse reaction, were comparatively investigated to elucidate the combinational effects of Y and/or La oxide promoters on the catalytic activity and anti-aging performance of monolithic cordierite honeycomb catalysts with low Pt and Rh content. The catalytic activities, water-gas shift (WGS) and steam reforming reaction (SR) were studied under a simulated gas mixture. The catalysts were also characterized by H 2 -temperature-programmed reduction (H 2 -TPR) and O 2 -temperature-programmed desorption (O 2 -TPD). The results showed that the prepared CeO 2 –ZrO 2 –M x O y oxides have a face-centered cubic fluorite structure and are nanosize. La 3+ ions can significantly improve thermal stability and efficiently retard CeO 2 –ZrO 2 crystal sintering and growth. Doped CeO 2 –ZrO 2 with Y 3+ and La 3+ has 105 and 60 m 2 /g surface area and 460 and 390 μmol/g OSC before and after aging. The T 50 of fresh Pt–Rh/CZYL/LA is 170 °C for CO, 222 °C for C 3 H 8 and 189 °C for NO, and shift to 205, 262 and 228 °C after hydrothermal aging, which are better than those of Pt–Rh/CZY/LA or Pt–Rh/CZL/LA. WGS and SR are relate to the OSC of oxygen storage materials and absorbed oxygen species on the catalyst surface and affect the three-way catalytic activities of catalysts. The reductive property of noble metals and the dissociatively adsorbed O 2 on the surface of catalysts are closely related to the catalytic activities.

  1. Customized binary and multi-level HfO2-x-based memristors tuned by oxidation conditions.

    Science.gov (United States)

    He, Weifan; Sun, Huajun; Zhou, Yaxiong; Lu, Ke; Xue, Kanhao; Miao, Xiangshui

    2017-08-30

    The memristor is a promising candidate for the next generation non-volatile memory, especially based on HfO 2-x , given its compatibility with advanced CMOS technologies. Although various resistive transitions were reported independently, customized binary and multi-level memristors in unified HfO 2-x material have not been studied. Here we report Pt/HfO 2-x /Ti memristors with double memristive modes, forming-free and low operation voltage, which were tuned by oxidation conditions of HfO 2-x films. As O/Hf ratios of HfO 2-x films increase, the forming voltages, SET voltages, and R off /R on windows increase regularly while their resistive transitions undergo from gradually to sharply in I/V sweep. Two memristors with typical resistive transitions were studied to customize binary and multi-level memristive modes, respectively. For binary mode, high-speed switching with 10 3 pulses (10 ns) and retention test at 85 °C (>10 4 s) were achieved. For multi-level mode, the 12-levels stable resistance states were confirmed by ongoing multi-window switching (ranging from 10 ns to 1 μs and completing 10 cycles of each pulse). Our customized binary and multi-level HfO 2-x -based memristors show high-speed switching, multi-level storage and excellent stability, which can be separately applied to logic computing and neuromorphic computing, further suitable for in-memory computing chip when deposition atmosphere may be fine-tuned.

  2. Crystallization behavior of Li2O-SiO2, Na2O-SiO2 and Na2O-CaO-SiO2 glasses; Li2O-SiO2, Na2O-SiO2, Na2O-CaO-SiO2 kei glass no kessho sekishutsu kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, K.; Otake, J.; Nagasaka, T.; Hino, M. [Tohoku University, Sendai (Japan)

    1998-06-01

    It has been known that crystallization of mold powder is effective on the disturbance of heat transfer between mold and solidified shell in production of middle carbon steel slabs in continuous casting process. But it has not yet been made clear which composition of mold powder is the most suitable for crystallization. The crystallization behavior of Li2O-SiO2, Na2O-SiO2 and Na2O-CaO-SiO2 glasses was observed by differential thermal analysis (DTA) and hot-thermocouple methods with DTA in the present work. As a result, addition of alkaline metal and alkaline earth metal oxides to SiO2 increased the critical cooling rate for glass formation in binary system of Li2O-SiO2 and Na2O-SiO2 and Li2O-SiO2 system crystallized easier than Na2O-SiO2 system. In ternary system of Na2O-CaO-SiO2, addition of Na2O hurried the critical cooling rate at CaO/SiO2=0.93 mass ratio, but the rate was almost constant in the composition range of more than 15 mass% Na2O. The slag of CaO/SiO2=0.93 made the rate faster than the slag of CaO/SiO2=0.47 at constant content of 10mass% Na2O. 17 refs., 10 figs., 3 tabs.

  3. Theoretical Limiting Potentials in Mg/O2 Batteries

    DEFF Research Database (Denmark)

    Smith, Jeffrey G.; Naruse, Junichi; Hiramatsu, Hidehiko

    2016-01-01

    A rechargeable battery based on a multivalent Mg/O2 couple is an attractive chemistry due to its high theoretical energy density and potential for low cost. Nevertheless, metal-air batteries based on alkaline earth anodes have received limited attention and generally exhibit modest performance....... In addition, many fundamental aspects of this system remain poorly understood, such as the reaction mechanisms associated with discharge and charging. The present study aims to close this knowledge gap and thereby accelerate the development of Mg/O2 batteries by employing first-principles calculations...... by the presence of large thermodynamic overvoltages. In contrast, MgO2-based cells are predicted to be much more efficient: superoxide-terminated facets on MgO2 crystallites enable low overvoltages and round-trip efficiencies approaching 90%. These data suggest that the performance of Mg/O2 batteries can...

  4. Single-walled carbon nanotube-facilitated dispersion of particulate TiO2 on ZrO2 ceramic membrane filters.

    Science.gov (United States)

    Yao, Yuan; Li, Gonghu; Gray, Kimberly A; Lueptow, Richard M

    2008-07-15

    We report that SWCNTs substantially improve the uniformity and coverage of TiO2 coatings on porous ZrO2 ceramic membrane filters. The ZrO2 filters were dip coated with 100 nm anatase TiO2, TiO2/SWCNT composites, a TiO2+SWCNT mixture, and a TiO2/MWCNT composite at pH 3, 5, and 8. Whereas the TiO2+SWCNT mixture and the TiO2/MWCNT composite promote better coverage and less clumping than TiO2 alone, the TiO2/SWCNT composite forms a complete uniform coating without cracking at pH 5 ( approximately 100% coverage). A combination of chemical and electrostatic effects between TiO2 and SWCNTs forming the composite as well as between the composite and the ZrO2 surface explains these observations.

  5. Influence of driving frequency on oxygen atom density in O2 radio frequency capacitively coupled plasma

    International Nuclear Information System (INIS)

    Kitajima, Takeshi; Noro, Kouichi; Nakano, Toshiki; Makabe, Toshiaki

    2004-01-01

    The influence of the driving frequency on the absolute oxygen atom density in an O 2 radio frequency (RF) capacitively coupled plasma (CCP) was investigated using vacuum ultraviolet absorption spectroscopy with pulse modulation of the main plasma. A low-power operation of a compact inductively coupled plasma light source was enabled to avoid the significant measurement errors caused by self-absorption in the light source. The pulse modulation of the main plasma enabled accurate absorption measurement for high plasma density conditions by eliminating background signals due to light emission from the main plasma. As for the effects of the driving frequency, the effect of VHF (100 MHz) drive on oxygen atom production was small because of the modest increase in plasma density of electronegative O 2 in contrast to the significant increase in electron density previously observed for electropositive Ar. The recombination coefficient of oxygen atoms on the electrode surface was obtained from a decay rate in the afterglow by comparison with a diffusion model, and it showed agreement with previously reported values for several electrode materials

  6. Analyses of surface coloration on TiO2 film irradiated with excimer laser

    International Nuclear Information System (INIS)

    Zheng, H.Y.; Qian, H.X.; Zhou, W.

    2008-01-01

    TiO 2 film of around 850 nm in thickness was deposited on a soda-lime glass by PVD sputtering and irradiated using one pulse of krypton-fluorine (KrF) excimer laser (wavelength of 248 nm and pulse duration of 25 ns) with varying fluence. The color of the irradiated area became darker with increasing laser fluence. Irradiated surfaces were characterized using optical microscopy, scanning electron microscopy, Raman spectroscopy and atomic force microscopy. Surface undergoes thermal annealing at low laser fluence of 400 and 590 mJ/cm 2 . Microcracks at medium laser fluence of 1000 mJ/cm 2 are attributed to surface melting and solidification. Hydrodynamic ablation is proposed to explain the formation of micropores and networks at higher laser fluence of 1100 and 1200 mJ/cm 2 . The darkening effect is explained in terms of trapping of light in the surface defects formed rather than anatase to rutile phase transformation as reported by others. Controlled darkening of TiO 2 film might be used for adjustable filters

  7. Maximization of current efficiency for organic pollutants oxidation at BDD, Ti/SnO2-Sb/PbO2, and Ti/SnO2-Sb anodes.

    Science.gov (United States)

    Xing, Xuan; Ni, Jinren; Zhu, Xiuping; Jiang, Yi; Xia, Jianxin

    2018-08-01

    Whereas electrochemical oxidation is noted for its ability to degrade bio-refractory organics, it has also been incorrectly criticized for excessive energy consumption. The present paper rectifies this misunderstanding by demonstrating that the energy actually consumed in the degradation process is much less than that wasted in the side reaction of oxygen evolution. To minimize the side reaction, the possible highest instantaneous current efficiency (PHICE) for electrochemical oxidation of phenol at Boron-doped Diamond (BDD), Ti/SnO 2 -Sb/PbO 2 (PbO 2 ), and Ti/SnO 2 -Sb (SnO 2 ) anodes has been investigated systematically, and found to reach almost 100% at the BDD anode compared with 23% at the PbO 2 anode and 9% at the SnO 2 anode. The significant discrepancy between PHICE values at the various anodes is interpreted in terms of different existing forms of hydroxyl radicals. For each anode system, the PHICEs are maintained experimentally using a computer-controlled exponential decay current mode throughout the electrolysis process. For applications, the minimized energy consumption is predicted by response surface methodology, and demonstrated for the BDD anode system. Consequently, almost 100% current efficiency is achieved (for a relatively meagre energy consumption of 17.2 kWh kgCOD -1 ) along with excellent COD degradation efficiency by optimizing the initial current density, flow rate, electrolysis time, and exponential decay constant. Compared with galvanostatic conditions, over 70% of the energy is saved in the present study, thus demonstrating the great potential of electrochemical oxidation for practical applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Molecular dynamics simulation based on the multi-component molecular orbital method: Application to H5O2+,D5O2+,andT5O2+

    International Nuclear Information System (INIS)

    Ishimoto, Takayoshi; Koyama, Michihisa

    2012-01-01

    Graphical abstract: Molecular dynamics method based on multi-component molecular orbital method was applied to basic hydrogen bonding systems, H 5 O 2 + , and its isotopomers (D 5 O 2 + andT 5 O 2 + ). Highlights: ► Molecular dynamics method with nuclear quantum effect was developed. ► Multi-component molecular orbital method was used as ab initio MO calculation. ► Developed method applied to basic hydrogen bonding system, H 5 O 2 + , and isotopomers. ► O ⋯ O vibrational stretching reflected to the distribution of protonic wavefunctions. ► H/D/T isotope effect was also analyzed. - Abstract: We propose a molecular dynamics (MD) method based on the multi-component molecular orbital (MC M O) method, which takes into account the quantum effect of proton directly, for the detailed analyses of proton transfer in hydrogen bonding system. The MC M O based MD (MC M O-MD) method is applied to the basic structures, H 5 O 2 + (called “Zundel ion”), and its isotopomers (D 5 O 2 + andT 5 O 2 + ). We clearly demonstrate the geometrical difference of hydrogen bonded O ⋯ O distance induced by H/D/T isotope effect because the O ⋯ O in H-compound was longer than that in D- or T-compound. We also find the strong relation between stretching vibration of O ⋯ O and the distribution of hydrogen bonded protonic wavefunction because the protonic wavefunction tends to delocalize when the O ⋯ O distance becomes short during the dynamics. Our proposed MC M O-MD simulation is expected as a powerful tool to analyze the proton dynamics in hydrogen bonding systems.

  9. Pulsed power

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The key element of our pulsed power program is concentration of power in time and space by suppression of breakdown in dielectrics and in vacuum. Magnetically insulated vacuum transmission lines and magnetic suppression of insulator flashover have continued as the main reserch directions. Vacuum insulated line studies at Physics International have been expanded and a test bed at Sandia, called MITE (Magnetically Insulated Transmission Experiment), is under development. The choice for the baseline EBFA design will depend on the outcome of these studies and should be made in July 1977. The slow and intermediate speed pulsed power approaches to EBFA will be based on Proto I and Proto II results and several of the projected EBFA subsystems are presently being tested in Proto II. A further stage of power concentration, within the vacuum diode itself, would considerably ease the burden on dielectrics; methods of power multiplication involving magnetically imploded plasmas are being considered and tests have begun using the Ripple III apparatus

  10. Production of TiO2 crystalline nanoparticles by laser ablation in ethanol

    International Nuclear Information System (INIS)

    Boutinguiza, M.; Rodriguez-Gonzalez, B.; Val, J. del; Comesaña, R.; Lusquiños, F.; Pou, J.

    2012-01-01

    Highlights: ► Nanoparticles of TiO 2 have been obtained by laser ablation of Ti submerged in ethanol using CW laser. ► The use of CW laser contributes to control the size distribution and to complete oxidation. ► The particles formation mechanism is the melting and rapid solidification. - Abstract: TiO 2 nanoparticles have received a special attention due to their applications in many different fields, such as catalysis, biomedical engineering, and energy conversion in solar cells. In this paper we report on the production of TiO 2 nanoparticles by means of a pulsed laser to ablate titanium metallic target submerged in ethanol. The results show that titanium crystalline dioxide nanoparticles can be obtained in a narrow size distribution. Crystalline phases, morphology and optical properties of the obtained colloidal nanoparticles were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and UV/vis absorption spectroscopy. The produced particles consisted mainly of titanium oxide crystalline nanoparticles showing spherical shape with most diameters ranging from 5 to 50 nm. Nanoparticles are polycrystalline exhibiting the coexistence of the three main phases with the predominance of brookite.

  11. Characterization of n-TiO2 thin films modified with silver nanoparticles

    International Nuclear Information System (INIS)

    Cueto, L.F.; Sanchez-Cervantes, E.M.

    2010-01-01

    Carbon dioxide accumulation in the atmosphere has gained much attention and has reopened many research lines that initiated two or three decades ago. Electrochemical reduction represents one of the most discussed methods, especially where semiconductor and metal-semiconductor cathodes are used to achieve CO 2 transformation into higher-energy products. In the present work, the influence of silver nanoparticles upon CO 2 reduction on n-TiO 2 cathodes in aqueous media is presented. Silver nanoparticles with an average diameter of 250nm were deposited on n-TiO 2 surfaces by the electrochemical Double-Pulse Potential method. A Grazing-Incidence X-Ray Diffraction structural analysis is presented showing the presence of metallic silver, while Atomic Force Microscopy shows surface roughness and particle size before and after surface modification. These measurements were confirmed by Scanning-Electron Microscopy acquainting for the formation of metal particles on the n-TiO 2 surface. Enhancement of CO 2 reduction by the presence of silver on cathodes is shown by cyclic voltammetry. (author)

  12. Effect Of Ti Powder Addition On The Fabrication Of TiO2 Nanopowders

    Directory of Open Access Journals (Sweden)

    Raihanuzzaman R.M.

    2015-06-01

    Full Text Available Sintered samples of Ti added TiO2 nanopowders were fabricated by combined application of magnetic pulsed compaction (MPC and sintering. The effect of Ti nano powder on density, shrinkage and hardness of the samples were investigated as part of the study. The optimum processing conditions were found to be around 0.5 GPa MPC pressure and 1450°C sintering temperature, illustrating maximum density, hardness and minimum shrinkage. High pressure compaction using MPC was found to enhance density with increasing MPC pressure up to 0.9 GPa, and significantly reduce the total shrinkage (about 16% in this case in the sintered bulks compared to other general processes (about 18%. While sintered samples blended with micro Ti showed presence of microstructural cracks, the samples with 1-2% nano Ti had less or no cracks on them. Overall, the inclusion of nano Ti indicated improvement in mechanical properties of TiO2 nanopowders sintered preforms as opposed to micro Ti-added TiO2.

  13. Microbial O2 consumption in the Aespoe tunnel

    International Nuclear Information System (INIS)

    Kotelnikova, S.; Pedersen, Karsten

    1998-04-01

    The report presents data on microbial O 2 reduction activities by microorganisms obtained with different techniques: Winkler method, gas chromatography, most probable numbering, enrichment technique, inhibitor analysis and radiotracer measurements. The samples were collected from boreholes and open funnel ponds at Aespoe in 1996-1998. The evaluation of the microbial activities in open ponds predicts the future microbial activities after the O 2 intrusion around the future repository. The metabolic potential of the microbial population inhabiting groundwater was evaluated on the basis of electron donors available and microbial 16S rRNA gene diversity. The contribution of different microbial groups to the O 2 reduction was elucidated using specific inhibitors selectively affecting different microbial groups. Our experiments show that microbial O 2 reduction occurs in deep groundwater. Carbon dioxide was produced concurrently with O 2 reduction confirming the biogenic nature of the reduction. The populations developed O 2 reduction rates and capacity depending on the initial concentration of dissolved O 2 reduction. Rates of O 2 reduction ranged from 0.32 to 4.5 μM/day. Depending on temperature and the type of groundwater the approximate time needed for consumption of 500 μM of dissolved O 2 ranged from 0.31 to 3.99 years. After approximately a 2 weeks period the microbial population in vitro was able to consume O 2 both at 30 deg C and 60 deg C. At 16 deg C no delay in O 2 consumption was observed. Our results demonstrated that methanotrophs survive in deep groundwater and that they were induced by O 2 . Some bacteria use Hg or CH 4 as electron donor instead of organic matter, which means that microbial O 2 reduction will occur also in deep groundwaters where the availability of organic carbon is limited. Specific CH 4 oxidation rates ranged between 3.00 and 220 nM CH 4 per litre per day. Comparison of the total O 2 reducing activities by gas chromatography and

  14. The protective roles of TiO2 nanoparticles against UV-B toxicity in Daphnia magna.

    Science.gov (United States)

    Liu, Jie; Wang, Wen-Xiong

    2017-09-01

    Aquatic environments are increasingly under environmental stress due to ultraviolet (UV) radiation and potential inputs of nanoparticles with intense application of nanotechnology. In this study, we investigated the interaction between UV-B radiation and titanium nanoparticles (TiO 2 -NPs) in a model freshwater cladoceran Daphnia magna. UV-B toxicity to Daphnia magna was examined when the daphnids were exposed to a range of TiO 2 -NPs concentrations with an initial 5 or 10min of 200μW/cm 2 UV-B radiation. In addition, UV-B toxicity was also examined in the presence of TiO 2 -NPs in the body of daphnids. Our results demonstrated that the daphnid mortality under UV-B radiation decreased significantly in the presence of TiO 2 -NPs both in the water and in the body, indicating that TiO 2 -NPs had some protective effects on D. magna against UV-B. Such protective effect was mainly caused by the blockage of UV-B by TiO 2 -NPs adsorption. UV-B produced reactive oxygen species (ROS) in the water and in the daphnids, which was not sufficient to cause mortality of daphnids over short periods of radiation. Previous studies focused on the effects of TiO 2 -NPs on the toxicity of total UV radiation, and did not attempt to differentiate the potential diverse roles of UV-A and UV-B. Our study indicated that TiO 2 -NPs may conversely protect the UV-B toxicity to daphnids. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. The comparison of photocatalytic activity of synthesized TiO2 and ZrO2 nanosize onto wool fibers

    International Nuclear Information System (INIS)

    Moafi, Hadi Fallah; Shojaie, Abdollah Fallah; Zanjanchi, Mohammad Ali

    2010-01-01

    TiO 2 and ZrO 2 nanocrystals were successfully synthesized and deposited onto wool fibers using the sol-gel technique at low temperature. The photocatalytic activities of TiO 2 -coated and ZrO 2 -coated wool fibers were measured by studying photodegradation of methylene blue and eosin yellowish dyes. The initial and the treated samples were characterized by several techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and X-ray diffraction. The TEM study shows dispersed particles with 10-30 nm in size for TiO 2 -coated and 20-40 nm in size for ZrO 2 -coated samples on the fiber surface. Comparison of the photocatalytic activity of the coated samples reveals superiority of TiO 2 modified sample with respect to that of ZrO 2 for degradation of both dyes. Our observations indicate that by applying this technique to the fabrics, self-cleaning materials could be designed for practical application.

  16. Epitaxial TiO 2/SnO 2 core-shell heterostructure by atomic layer deposition

    KAUST Repository

    Nie, Anmin; Liu, Jiabin; Li, Qianqian; Cheng, Yingchun; Dong, Cezhou; Zhou, Wu; Wang, Pengfei; Wang, Qingxiao; Yang, Yang; Zhu, Yihan; Zeng, Yuewu; Wang, Hongtao

    2012-01-01

    Taking TiO 2/SnO 2 core-shell nanowires (NWs) as a model system, we systematically investigate the structure and the morphological evolution of this heterostructure synthesized by atomic layer deposition/epitaxy (ALD/ALE). All characterizations

  17. Ge interactions on HfO2 surfaces and kinetically driven patterning of Ge nanocrystals on HfO2

    International Nuclear Information System (INIS)

    Stanley, Scott K.; Joshi, Sachin V.; Banerjee, Sanjay K.; Ekerdt, John G.

    2006-01-01

    Germanium interactions are studied on HfO 2 surfaces, which are prepared through physical vapor deposition (PVD) and by atomic layer deposition. X-ray photoelectron spectroscopy and temperature-programed desorption are used to follow the reactions of germanium on HfO 2 . Germanium chemical vapor deposition at 870 K on HfO 2 produces a GeO x adhesion layer, followed by growth of semiconducting Ge 0 . PVD of 0.7 ML Ge (accomplished by thermally cracking GeH 4 over a hot filament) also produces an initial GeO x layer, which is stable up to 800 K. PVD above 2.0 ML deposits semiconducting Ge 0 . Temperature programed desorption experiments of ∼1.0 ML Ge from HfO 2 at 400-1100 K show GeH 4 desorption below 600 K and GeO desorption above 850 K. These results are compared to Ge on SiO 2 where GeO desorption is seen at 550 K. Exploiting the different reactivity of Ge on HfO 2 and SiO 2 allows a kinetically driven patterning scheme for high-density Ge nanoparticle growth on HfO 2 surfaces that is demonstrated

  18. Dynamic shock compaction of a ZrO2-RuO2 electronic nanocomposite: toward functionally graded materials

    NARCIS (Netherlands)

    van Zyl, W.E.; Carton, Erik P.; Raming, T.P.; ten Elshof, Johan E.; Verweij, H.

    2005-01-01

    An electronic ZrO2-RuO2 nanocomposite was fabricated by dynamic compaction (DC) at 1.5 GPa resulting in a maximum relative density of 88% in the material. The DC process formed pristine elongated conical-shaped compacts 3 cm in length. The compacts retained their original nanometer-sized grains (~20

  19. The influence of TiO2 particle size and conductivity of the CuCrO2 ...

    Indian Academy of Sciences (India)

    38

    Keywords: Solid-state dye-sensitized solar cells, Sol-Gel method, TiO2 nanoparticle, .... at 2.0 by dropwise addition of 0.1 M hydrochloric acid with vigorous stirring. The ... The TiO2 pastes were prepared by Pechini-type sol-gel method [26, 27].

  20. Synthesis of hybrid cellulose nanocomposite bonded with dopamine SiO2/TiO2 and its antimicrobial activity

    Science.gov (United States)

    Ramesh, Sivalingam; Kim, Gwang-Hoon; Kim, Jaehwan; Kim, Joo-Hyung

    2015-04-01

    Organic-inorganic hybrid material based cellulose was synthesized by the sol-gel approach. The explosion of activity in this area in the past decade has made tremendous progress in industry or academic both fundamental understanding of sol-gel process and applications of new functionalized hybrid materials. In this present research work, we focused on cellulose-dopamine functionalized SiO2/TiO2 hybrid nanocomposite by sol-gel process. The cellulose-dopamine hybrid nanocomposite was synthesized via γ-aminopropyltriethoxysilane (γ-APTES) coupling agent by in-situ sol-gel process. The chemical structure of cellulose-amine functionalized dopamine bonding to cellulose structure with covalent cross linking hybrids was confirmed by FTIR spectral analysis. The morphological analysis of cellulose-dopamine nanoSiO2/TiO2 hybrid nanocomposite materials was characterized by XRD, SEM and TEM. From this different analysis results indicate that the optical transparency, thermal stability, control morphology of cellulose-dopamine-SiO2/TiO2 hybrid nanocomposite. Furthermore cellulose-dopamine-SiO2/TiO2 hybrid nanocomposite was tested against pathogenic bacteria for antimicrobial activity.

  1. Optimization of CeO2-ZrO2 mixed oxide catalysts for ethyl acetate combustion

    Czech Academy of Sciences Publication Activity Database

    Dimitrov, M.; Ivanova, R.; Štengl, Václav; Henych, Jiří; Kovacheva, D.; Tsoncheva, T.

    2015-01-01

    Roč. 47, č. 1 (2015), s. 323-329 ISSN 0324-1130 Institutional support: RVO:61388980 Keywords : nanosized CeO2-ZrO2 * mixed oxide phase * ethyl acetate combustion Subject RIV: CA - Inorganic Chemistry Impact factor: 0.229, year: 2015

  2. Reactions of Ferrous Coproheme Decarboxylase (HemQ) with O2 and H2O2 Yield Ferric Heme b.

    Science.gov (United States)

    Streit, Bennett R; Celis, Arianna I; Shisler, Krista; Rodgers, Kenton R; Lukat-Rodgers, Gudrun S; DuBois, Jennifer L

    2017-01-10

    A recently discovered pathway for the biosynthesis of heme b ends in an unusual reaction catalyzed by coproheme decarboxylase (HemQ), where the Fe(II)-containing coproheme acts as both substrate and cofactor. Because both O 2 and H 2 O 2 are available as cellular oxidants, pathways for the reaction involving either can be proposed. Analysis of reaction kinetics and products showed that, under aerobic conditions, the ferrous coproheme-decarboxylase complex is rapidly and selectively oxidized by O 2 to the ferric state. The subsequent second-order reaction between the ferric complex and H 2 O 2 is slow, pH-dependent, and further decelerated by D 2 O 2 (average kinetic isotope effect of 2.2). The observation of rapid reactivity with peracetic acid suggested the possible involvement of Compound I (ferryl porphyrin cation radical), consistent with coproheme and harderoheme reduction potentials in the range of heme proteins that heterolytically cleave H 2 O 2 . Resonance Raman spectroscopy nonetheless indicated a remarkably weak Fe-His interaction; how the active site structure may support heterolytic H 2 O 2 cleavage is therefore unclear. From a cellular perspective, the use of H 2 O 2 as an oxidant in a catalase-positive organism is intriguing, as is the unusual generation of heme b in the Fe(III) rather than Fe(II) state as the end product of heme synthesis.

  3. Influence of TiO2 particle size and conductivity of the CuCrO2 ...

    Indian Academy of Sciences (India)

    2017-11-28

    Nov 28, 2017 ... Solid-state dye-sensitized solar cells; sol–gel method; TiO2 nanoparticle; CuCrO2 nanoparticles; electrical ... The purpose of this work is construction and optimization .... can be attributed to the electron transport mechanism.

  4. Photo-induced tunneling currents in MOS structures with various HfO2/SiO2 stacking dielectrics

    Directory of Open Access Journals (Sweden)

    Chin-Sheng Pang

    2014-04-01

    Full Text Available In this study, the current conduction mechanisms of structures with tandem high-k dielectric in illumination are discussed. Samples of Al/SiO2/Si (S, Al/HfO2/SiO2/Si (H, and Al/3HfO2/SiO2/Si (3H were examined. The significant observation of electron traps of sample H compares to sample S is found under the double bias capacitance-voltage (C-V measurements in illumination. Moreover, the photo absorption sensitivity of sample H is higher than S due to the formation of HfO2 dielectric layer, which leads to larger numbers of carriers crowded through the sweep of VG before the domination of tunneling current. Additionally, the HfO2 dielectric layer would block the electrons passing through oxide from valance band, which would result in less electron-hole (e−-h+ pairs recombination effect. Also, it was found that both of the samples S and H show perimeter dependency of positive bias currents due to strong fringing field effect in dark and illumination; while sample 3H shows area dependency of positive bias currents in strong illumination. The non-uniform tunneling current through thin dielectric and through HfO2 stacking layers are importance to MOS(p tunneling photo diodes.

  5. Polyaniline assisted by TiO2:SnO2 nanoparticles as a hydrogen gas sensor at environmental conditions

    Science.gov (United States)

    Nasirian, Shahruz; Milani Moghaddam, Hossain

    2015-02-01

    In the present research, polyaniline assisted by TiO2:SnO2 nanoparticles was synthesized and deposited onto an epoxy glass substrate with Cu-interdigited electrodes for gas sensing application. To examine the efficiency of the polyaniline/TiO2:SnO2 nanocomposite (PTS) as a hydrogen (H2) gas sensor, its nature, stability, response, recovery/response time have been studied with a special focus on its ability to work at environmental conditions. H2 gas sensing results demonstrated that a PTS sensor with 20 and 10 wt% of anatase-TiO2 and SnO2 nanoparticles, respectively, has the best response time (75 s) with a recovery time of 117 s at environmental conditions. The highest (lowest) response (recovery time) was 6.18 (46 s) in PTS sensor with 30 and 15 wt% of anatase- (rutile-)TiO2 and SnO2 nanoparticles, respectively, at 0.8 vol.% H2 gas. Further, the H2 gas sensing mechanism of PTS sensor has also been studied.

  6. Efectos de fotodegradación propiciados por recubrimientos de TiO2 y TiO2-SiO2 obtenidos por Sol-Gel

    Directory of Open Access Journals (Sweden)

    Rodriguez Paez, J. E.

    2008-10-01

    Full Text Available Photodegradation effect is widely used for water purification this contributes to preservation and protection of environment. Titanium oxide, (TiO2, is a compound that shows up this phenomenon. TiO2 is a semiconductor which may degradate pollutants through of a oxidation process. It permit the treatment of the residual water. It this work we has conformed coatings of TiO2 y TiO2-SiO2, utilized Sol-Gel method and investigated the degradation of the blue Methylene. For this, we introduced these coatings in the blue methylene solution which was illuminated with radiation of λ=365nm to activate its photocatilist properties. The structures of the coatings were characterized using Atomic Force Microscopy (AFM and X-ray Photoelectron Spectroscopy (XPS.El efecto de fotodegradación es ampliamente utilizado para la purificación del agua, acción que contribuye a la conservación y protección del medio ambiente; el óxido de titanio (TiO2 es uno de los semiconductores que pueden degradar contaminantes mediante procesos de oxidación, lo que lo hace apto para el tratamiento de aguas residuales. En este trabajo se conformaron recubrimientos de TiO2 y TiO2-SiO2, por el método Sol-Gel, y se estudio la degradación que experimentaba una solución de azul de metileno al introducirle estos recubrimientos e iluminarlos con una radiación de λ=365nm para activar su propiedad fotocatalítica. Los recubrimientos fueron caracterizados microestructuralmente utilizando Microscopía de Fuerza Atómica (MFA y Espectroscopía de Fotoelectrones de rayos X (XPS. Los resultados obtenidos de los ensayos de fotodegradación indican que los recubrimientos con una cantidad pequeña de silicio presentan un mayor efecto de fotodegradación indicando que el silicio puede generar puntos de anclaje que facilitan las reacciones de fotocatálisis. Por otro lado, la formación de centros activos, constituidos principalmente por carbono, también contribuyeron al desarrollo de estas

  7. Gold nanoparticles-immobilized, hierarchically ordered, porous TiO2 nanotubes for biosensing of glutathione

    Directory of Open Access Journals (Sweden)

    Sheen Mers SV

    2015-10-01

    Full Text Available SV Sheen Mers,1,2 Elumalai Thambuswamy Deva Kumar,1 V Ganesh1,2 1Electrodics and Electrocatalysis (EEC Division, Council of Scientific and Industrial Research–Central Electrochemical Research Institute (CSIR–CECRI, Karaikudi, Tamil Nadu, India; 2Academy of Scientific and Innovative Research (AcSIR, New Delhi, India Abstract: Glutathione (GSH is vital for several functions of our human body such as neutralization of free radicals and reactive oxygen compounds, maintaining the active forms of vitamin C and E, regulation of nitric oxide cycle, iron metabolism, etc. It is also an endogenous antioxidant in most of the biological reactions. Given the importance of GSH, a simple strategy is proposed in this work to develop a biosensor for quantitative detection of GSH. This particular biosensor comprises of gold nanoparticles (Au NPs-immobilized, hierarchically ordered titanium dioxide (TiO2 porous nanotubes. Hexagonally arranged, honeycomb-like nanoporous tubular TiO2 electrodes are prepared by using a simple electrochemical anodization process by applying a constant potential of 30 V for 24 hours using ethylene glycol consisting of ammonium fluoride as an electrolytic medium. Structural morphology and crystalline nature of such TiO2 nanotubes are analyzed using field emission scanning electron microscope (FESEM and X-ray diffraction (XRD. Interestingly, nanocomposites of TiO2 with Au NPs is prepared in an effort to alter the intrinsic properties of TiO2, especially tuning of its band gap. Au NPs are prepared by a well-known Brust and Schiffrin method and are immobilized onto TiO2 electrodes which act as a perfect electrochemical sensing platform for GSH detection. Structural characterization and analysis of these modified electrodes are performed using FESEM, XRD, and UV-visible spectroscopic studies. GSH binding events on Au NPs-immobilized porous TiO2 electrodes are monitored by electrochemical techniques, namely, cyclic voltammetry (CV and

  8. Growth and characterization of hydroxyapatite nanorice on TiO2 nanofibers

    KAUST Repository

    Chetibi, Loubna

    2014-04-01

    Hydroxyapatite (HA) coating with nanoparticles like nanorice is fabricated on chemically pretreated titanium (Ti) surface, through an electrochemical deposition approach, for biomaterial applications. The Ti surface was chemically patterned with anatase TiO2 nanofibers. These nanofibers were prepared by in situ oxidation of Ti foils in a concentrated solution of H 2O2 and NaOH, followed by proton exchange and calcinations. Afterward, TiO2 nanofibers on Ti substrate were coated with HA nanoparticles like nanorice. The obtained samples were annealed at high temperature to produce inter diffusion between TiO2 and HA layers. The resultant layers were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Infrared Spectroscopy (FTIR), corrosion tests in SBF solution, and Electron Probe Micro Analysis (EPMA). It was found that only Ti from the titanium substrate diffuses into the HA coating and a good corrosion resistance in simulated body fluid was obtained. © 2014 Elsevier B.V. All rights reserved.

  9. Highly Efficient Light-Driven TiO2-Au Janus Micromotors.

    Science.gov (United States)

    Dong, Renfeng; Zhang, Qilu; Gao, Wei; Pei, Allen; Ren, Biye

    2016-01-26

    A highly efficient light-driven photocatalytic TiO2-Au Janus micromotor with wireless steering and velocity control is described. Unlike chemically propelled micromotors which commonly require the addition of surfactants or toxic chemical fuels, the fuel-free Janus micromotor (diameter ∼1.0 μm) can be powered in pure water under an extremely low ultraviolet light intensity (2.5 × 10(-3) W/cm(2)), and with 40 × 10(-3) W/cm(2), they can reach a high speed of 25 body length/s, which is comparable to common Pt-based chemically induced self-electrophoretic Janus micromotors. The photocatalytic propulsion can be switched on and off by incident light modulation. In addition, the speed of the photocatalytic TiO2-Au Janus micromotor can be accelerated by increasing the light intensity or by adding low concentrations of chemical fuel H2O2 (i.e., 0.1%). The attractive fuel-free propulsion performance, fast movement triggering response, low light energy requirement, and precise motion control of the TiO2-Au Janus photocatalytic micromotor hold considerable promise for diverse practical applications.

  10. OH Production Enhancement in Bubbling Pulsed Discharges

    Science.gov (United States)

    Lungu, Cristian P.; Porosnicu, Corneliu; Jepu, Ionut; Chiru, Petrica; Zaroschi, Valentin; Lungu, Ana M.; Saito, Nagahiro; Bratescu, Maria; Takai, Osamu; Velea, Theodor; Predica, Vasile

    2010-10-01

    The generation of active species, such as H2O2, O*, OH*, HO2*, O3, N2*, etc, produced in aqueous solutions by HV pulsed discharges was studied in order to find the most efficient way in waste water treatment taking into account that these species are almost stronger oxidizers than ozone. Plasma was generated inside gas bubbles formed by the argon, air and oxygen gas flow between the special designed electrodes. The pulse width and pulse frequency influence was studied in order to increase the efficiency of the OH active species formation. The produced active species were investigated by optical emission spectroscopy and correlated with electrical parameters of the discharges (frequency, pulse width, amplitude, and rise and decay time).

  11. OH Production Enhancement in Bubbling Pulsed Discharges

    International Nuclear Information System (INIS)

    Lungu, Cristian P.; Porosnicu, Corneliu; Jepu, Ionut; Chiru, Petrica; Zaroschi, Valentin; Lungu, Ana M.; Saito, Nagahiro; Bratescu, Maria; Takai, Osamu; Velea, Theodor; Predica, Vasile

    2010-01-01

    The generation of active species, such as H 2 O 2 , O * , OH*, HO 2 *, O 3 , N 2 * , etc, produced in aqueous solutions by HV pulsed discharges was studied in order to find the most efficient way in waste water treatment taking into account that these species are almost stronger oxidizers than ozone. Plasma was generated inside gas bubbles formed by the argon, air and oxygen gas flow between the special designed electrodes. The pulse width and pulse frequency influence was studied in order to increase the efficiency of the OH active species formation. The produced active species were investigated by optical emission spectroscopy and correlated with electrical parameters of the discharges (frequency, pulse width, amplitude, and rise and decay time).

  12. Effects of deposition rates on laser damage threshold of TiO2/SiO2 high reflectors

    International Nuclear Information System (INIS)

    Yao Jianke; Xu Cheng; Ma Jianyong; Fang Ming; Fan Zhengxiu; Jin Yunxia; Zhao Yuanan; He Hongbo; Shao Jianda

    2009-01-01

    TiO 2 single layers and TiO 2 /SiO 2 high reflectors (HR) are prepared by electron beam evaporation at different TiO 2 deposition rates. It is found that the changes of properties of TiO 2 films with the increase of rate, such as the increase of refractive index and extinction coefficient and the decrease of physical thickness, lead to the spectrum shift and reflectivity bandwidth broadening of HR together with the increase of absorption and decrease of laser-induced damage threshold. The damages are found of different morphologies: a shallow pit to a seriously delaminated and deep crater, and the different amorphous-to-anatase-to-rutile phase transition processes detected by Raman study. The frequency shift of Raman vibration mode correlates with the strain in film. Energy dispersive X-ray analysis reveals that impurities and non-stoichiometric defects are two absorption initiations resulting to the laser-induced transformation.

  13. Structural and morphological characterization of TiO2-ZrO2 powders obtained by the polymeric precursors method

    International Nuclear Information System (INIS)

    Ribeiro, M.A.; Gama, L.; Bispo, A.; Neiva, L.S.; Bernardi, M.I.B.; Kiminami, R.H.G.A.

    2010-01-01

    This work aims to characterize the structure and morphology of TiO 2 -ZrO 2 powders obtained by polymeric precursor method. For this we studied the following compositions: 0.25, 0.5 and 0.75 moles of Zr and calcined at 800 deg C for one hour. The powders obtained were characterized by XRD, SEM and nitrogen adsorption (BET). The analysis of X-ray diffraction showed that the powders had a phase of TiO 2 in the anatase form and a tetragonal phase of ZrO 2 . The crystallite size was between 8, 13 and 11 nm respectively. The analysis of scanning electron microscopy showed the growth of ZrO 2 nanoparticles and that these comprise spherical agglomerates of less than 100 nm. Particle size determined by the BET ranging 28.1-29.5 nm, showing thereby the character of nanosized powders. (author)

  14. Nanocrystal in Er3+-doped SiO2-ZrO2 Planar Waveguide with Yb3+ Sensitizer

    International Nuclear Information System (INIS)

    Razaki, N. Iznie; Jais, U. Sarah; Abd-Rahman, M. Kamil; Bhaktha, S. N. B.; Chiasera, A.; Ferrari, M.

    2010-01-01

    Higher doping of Er 3+ in glass ceramic waveguides would cause concentration and pair-induced quenching which lead to inhomogeneous line-width of luminescence spectrum thus reduce output intensity. Concentration quenching can be overcome by introducing ZrO 2 in the glass matrix while co-doping with Yb 3+ which acts as sensitizer would improve the excitation efficiency of Er 3+ . In this study, SiO 2 -ZrO 2 planar waveguides having composition in mol percent of 70SiO 2 -30ZrO 2 doped with Er 3+ and co-doped with Yb 3+ , were prepared via sol-gel route. Narrower and shaper peaks of PL and XRD shows the formation of nanocrystals. Intensity is increase with addition amount of Yb 3+ shows sensitizing effect on Er 3+ .

  15. Crystallization behaviour of nanostructured hybrid SiO2-TiO2 gel glasses to nanocomposites.

    Science.gov (United States)

    Tsvetelina, Gerganova; Yordanka, Ivanova; Yuliya, Vueva; Miranda, Salvado Isabel M; Helena, Fernandes Maria

    2010-04-01

    The crystallization behaviour of hybrid SiO2-TiO2 nanocomposites derived from titanosiloxanes by sol-gel method has been investigated depending on the type of siloxane precursor and the pirolysis temperature. The resulting hybrid titanosiloxanes, crosslinked with trimethylsilil isocyanate (nitrogen-modified) or methyltrietoxisilane (carbon-modified), were pirolyzed in an inert atmosphere in the temperature range between 600 to 1100 degrees C in order to form C-(N)-Si-O-TiO2 nanocomposites. By means of XRD, FTIR, 29Si NMR, SEM, TEM and AFM investigations have been established that the transformation of the nanostructured SiO2-TiO2 hybrid materials into nanocomposites as well as the crystalline size depend on the titanium content and the type of cross-linking agents used in the synthesizes.

  16. MOD approach for the growth of epitaxial CeO2 buffer layers on biaxially textured Ni-W substrates for YBCO coated conductors

    International Nuclear Information System (INIS)

    Bhuiyan, M S; Paranthaman, M; Sathyamurthy, S; Aytug, T; Kang, S; Lee, D F; Goyal, A; Payzant, E A; Salama, K

    2003-01-01

    We have grown epitaxial CeO 2 buffer layers on biaxially textured Ni-W substrates for YBCO coated conductors using a newly developed metal organic decomposition (MOD) approach. Precursor solution of 0.25 M concentration was spin coated on short samples of Ni-3 at%W (Ni-W) substrates and heat-treated at 1100 C in a gas mixture of Ar-4%H 2 for 15 min. Detailed x-ray studies indicate that CeO 2 films have good out-of-plane and in-plane textures with full-width-half-maximum values of 5.8 deg. and 7.5 deg., respectively. High temperature in situ XRD studies show that the nucleation of CeO 2 films starts at 600 C and the growth completes within 5 min when heated at 1100 C. SEM and AFM investigations of CeO 2 films reveal a fairly dense microstructure without cracks and porosity. Highly textured YSZ barrier layers and CeO 2 cap layers were deposited on MOD CeO 2 -buffered Ni-W substrates using rf-magnetron sputtering. Pulsed laser deposition (PLD) was used to grow YBCO films on these substrates. A critical current, J c , of about 1.5 MA cm -2 at 77 K and self-field was obtained on YBCO (PLD)/CeO 2 (sputtered)/YSZ (sputtered)/CeO 2 (spin-coated)/Ni-W

  17. Aortic-Radial Pulse Wave Velocity Ratio in End-stage Renal Disease Patients: Association with Age, Body Tissue Hydration Status, Renal Failure Etiology and Five Years of Hemodialysis.

    Science.gov (United States)

    Bia, Daniel; Valtuille, Rodolfo; Galli, Cintia; Wray, Sandra; Armentano, Ricardo; Zócalo, Yanina; Cabrera-Fischer, Edmundo

    2017-03-01

    The etiology of the end-stage renal disease (ESRD) and the hydration status may be involved in the arterial stiffening process observed in hemodialyzed patients. The ratio between carotid-femoral and carotid-radial pulse wave velocity (PWV ratio) was recently proposed to characterize the patient-specific stiffening process. to analyze: (1) the PWV-ratio in healthy and hemodialyzed subjects, analyzing potential changes associated to etiologies of the ESRD, (2) the PWV-ratio and hydration status using multiple-frequency bioimpedance and, (3) the effects of hemodialysis on PWV-ratio in a 5-year follow-up. PWV-ratio was evaluated in 151 patients differentiated by the pathology determining their ESRD. Total body fluid (TBF), intra and extra cellular fluid (ICF, ECF) were measured in 65 of these patients using bioelectrical-impedance. The association between arterial, hemodynamic or fluid parameters was analyzed. PWV-ratio was evaluated in a group of patients (n = 25) 5 years later (follow-up study). PWV-ratio increased in the ESRD cohort with respect to the control group (1.03 ± 0.23 vs. 1.31 ± 0.37; p hydration status, but not with the blood pressure. PWV-ratio could be considered a blood pressure-independent parameter, associated with the age and hydration status of the patient.

  18. Impact of nano and bulk ZrO2, TiO2 particles on soil nutrient contents and PGPR.

    Science.gov (United States)

    Karunakaran, Gopalu; Suriyaprabha, Rangaraj; Manivasakan, Palanisamy; Yuvakkumar, Rathinam; Rajendran, Venkatachalam; Kannan, Narayanasamy

    2013-01-01

    Currently, nanometal oxides are used extensively in different industries such as medicine, cosmetics and food. The increased consumption of nanoparticles (NPs) leads the necessity to understand the fate of the nanoparticles in the environment. The present study focused on the ecotoxicological behaviour of bulk and nano ZrO2 (Zirconia) and TiO2 (Titania) particles on PGPR (plant growth promoting rhizobacteria), soil and its nutrient contents. The microbial susceptibility study showed that nano TiO2 had 13 +/- 0.9 mm (B. megaterium), 15 +/- 0.2 mm (P. fluorescens), 16 +/- 0.2 mm (A. vinelandii) and 12 +/- 0.3 mm (B. brevis) zones of inhibition. However, nano and bulk ZrO2 particles were non-toxic to PGPR. In addition, it was found that toxicity varied depends on the medium of reaction. The soil study showed that nano TiO2 was found to be highly toxic, whereas bulk TiO2 was less toxic towards soil bacterial populations at 1000 mg L(-1). In contrast, nano and bulk ZrO2 were found to be inert at 1000 mg L(-1). The observed zeta potential and hydrophobicity of TiO2 particles causes more toxic than ZrO2 in parallel with particle size. However, nano TiO2 decreases the microbial population as well as nutrient level of the soil but not zirconia. Our finding shows that the mechanism of toxicity depends on size, hydrophobic potential and zeta potential of the metal oxide particles. Thus, it is necessary to take safety measures during the disposal and use of such toxic nanoparticles in the soil to prevent their hazardous effects.

  19. Fractography of STIR casted Al-ZrO2 composites

    International Nuclear Information System (INIS)

    Baghchesara, M. A.; Abdizadeh, H.; Baharvandi, H. R.

    2009-01-01

    In this study, Al-ZrO 2 composites were produced by Vortex method using ZrO 2 powder with 1 micron average diameter as reinforce particles and Al-356 as the matrix metal. The melt composites were stirred for 13 minutes, then casted into a metallic mold. Different samples of 5, 10 and 15 volume percent of ZrO 2 , in different casting temperatures of 750, 850 and 950 d eg C were produced. The latter 2 casting temperatures are not a common practice but were chosen to enhance fluidity. Effects of volume percent of ZrO 2 particles and casting temperature on tensile strength, microstructure, and fracture surfaces of Al-ZrO 2 composites have been investigated. The highest tensile strength was achieved in the specimen containing 15 vol. % ZrO 2 produced at 750 d eg C which shows an increase of 60% in comparison to the Al-356 non-reinforced alloy. Microscopic investigations of fracture surfaces revealed that fracture in a brittle manner with little or no necking happening. By increasing ZrO 2 content and casting temperature, the composites fracture goes in a more severely brittle manner.

  20. Photocatalytic application of TiO2/SiO2-based magnetic nanocomposite (Fe3O4@SiO2/TiO2 for reusing of textile wastewater

    Directory of Open Access Journals (Sweden)

    Laleh Enayati Ahangar

    2016-01-01

    Full Text Available In this research we have developed a treatment method for textile wastewater by TiO2/SiO2-based magnetic nanocomposite. Textile wastewater includes a large variety of dyes and chemicals and needs treatments. This manuscript presents a facile method for removing dyes from the textile wastewater by using TiO2/SiO2-based nanocomposite (Fe3O4@SiO2/TiO2 under UV irradiation. This magnetic nanocomposite, as photocatalytically active composite, is synthesized via solution method in mild conditions. A large range of cationic, anionic and neutral dyes including: methyl orange, methylene blue, neutral red, bromocresol green and methyl red are used for treatment investigations. Neutral red and bromocresol green have good results in reusing treatment. The high surface area of nanocomposites improve the kinetic of wastewater treatment. In this method, by using the magnetic properties of Fe3O4 nanoparticles, TiO2-based photocatalyst could be separated and reused for 3 times. The efficiency of this method is respectively 100% and 65% for low concentration (10 ppm and high concentration (50 ppm of neutral red and bromocrosol green after 3 h treatment. The efficiency of treatment using the second used nanocomposite was 90% for 10 ppm of the same dyes.

  1. Oriented epitaxial TiO2 nanowires for water splitting

    Science.gov (United States)

    Hou, Wenting; Cortez, Pablo; Wuhrer, Richard; Macartney, Sam; Bozhilov, Krassimir N.; Liu, Rong; Sheppard, Leigh R.; Kisailus, David

    2017-06-01

    Highly oriented epitaxial rutile titanium dioxide (TiO2) nanowire arrays have been hydrothermally grown on polycrystalline TiO2 templates with their orientation dependent on the underlying TiO2 grain. Both the diameter and areal density of the nanowires were tuned by controlling the precursor concentration, and the template surface energy and roughness. Nanowire tip sharpness was influenced by precursor solubility and diffusivity. A new secondary ion mass spectrometer technique has been developed to install additional nucleation sites in single crystal TiO2 templates and the effect on nanowire growth was probed. Using the acquired TiO2 nanowire synthesis knowhow, an assortment of nanowire arrays were installed upon the surface of undoped TiO2 photo-electrodes and assessed for their photo-electrochemical water splitting performance. The key result obtained was that the presence of short and dispersed nanowire arrays significantly improved the photocurrent when the illumination intensity was increased from 100 to 200 mW cm-2. This is attributed to the alignment of the homoepitaxially grown nanowires to the [001] direction, which provides the fastest charge transport in TiO2 and an improved pathway for photo-holes to find water molecules and undertake oxidation. This result lays a foundation for achieving efficient water splitting under conditions of concentrated solar illumination.

  2. High pressure synthesis of amorphous TiO2 nanotubes

    Directory of Open Access Journals (Sweden)

    Quanjun Li

    2015-09-01

    Full Text Available Amorphous TiO2 nanotubes with diameters of 8-10 nm and length of several nanometers were synthesized by high pressure treatment of anatase TiO2 nanotubes. The structural phase transitions of anatase TiO2 nanotubes were investigated by using in-situ high-pressure synchrotron X-ray diffraction (XRD method. The starting anatase structure is stable up to ∼20GPa, and transforms into a high-density amorphous (HDA form at higher pressure. Pressure-modified high- to low-density transition was observed in the amorphous form upon decompression. The pressure-induced amorphization and polyamorphism are in good agreement with the previous results in ultrafine TiO2 nanoparticles and nanoribbons. The relationship between the LDA form and α-PbO2 phase was revealed by high-resolution transmission electron microscopy (HRTEM study. In addition, the bulk modulus (B0 = 158 GPa of the anatase TiO2 nanotubes is smaller than those of the corresponding bulks and nanoparticles (180-240 GPa. We suggest that the unique open-ended nanotube morphology and nanosize play important roles in the high pressure phase transition of TiO2 nanotubes.

  3. Advanced Pulse Oximetry System for Remote Monitoring and Management

    Science.gov (United States)

    Pak, Ju Geon; Park, Kee Hyun

    2012-01-01

    Pulse oximetry data such as saturation of peripheral oxygen (SpO2) and pulse rate are vital signals for early diagnosis of heart disease. Therefore, various pulse oximeters have been developed continuously. However, some of the existing pulse oximeters are not equipped with communication capabilities, and consequently, the continuous monitoring of patient health is restricted. Moreover, even though certain oximeters have been built as network models, they focus on exchanging only pulse oximetry data, and they do not provide sufficient device management functions. In this paper, we propose an advanced pulse oximetry system for remote monitoring and management. The system consists of a networked pulse oximeter and a personal monitoring server. The proposed pulse oximeter measures a patient's pulse oximetry data and transmits the data to the personal monitoring server. The personal monitoring server then analyzes the received data and displays the results to the patient. Furthermore, for device management purposes, operational errors that occur in the pulse oximeter are reported to the personal monitoring server, and the system configurations of the pulse oximeter, such as thresholds and measurement targets, are modified by the server. We verify that the proposed pulse oximetry system operates efficiently and that it is appropriate for monitoring and managing a pulse oximeter in real time. PMID:22933841

  4. Anatase phase stability and doping concentration dependent refractivity in codoped transparent conducting TiO2 films

    International Nuclear Information System (INIS)

    Chen, T L; Furubayashi, Y; Hirose, Y; Hitosugi, T; Shimada, T; Hasegawa, T

    2007-01-01

    Nb 0.06 Sn x Ti 0.94-x O 2 (x ≤ 0.3) thin films were grown by a pulsed-laser deposition method with varying Sn concentration. Through a combinatorial technique, we find that Sn concentration can reach a maximum of about x = 0.3 while maintaining the stable anatase phase and epitaxy. A doping concentration dependence of the refractivity is revealed, in which refractivity reduction at a wavelength of λ = 500 nm is estimated to be 12.4% for Nb 0.06 Sn 0.3 Ti 0.64 O 2 thin film. Sn doping induced band-gap blue shift can be contributed to the mixing of extended Sn 5s orbitals with the conduction band of TiO 2 . Low resistivity on the order of 10 -4 Ω cm at room temperature and high internal transmittance of more than 95% in the visible light region are exhibited for Nb 0.06 Sn x Ti 0.94-x O 2 thin films (x ≤ 0.2). Optical and transport analyses demonstrate that doping Sn into Nb 0.06 Ti 0.94 O 2 can reduce the refractivity while maintaining low resistivity and high transparency

  5. Evaluation of micro-abrasion-corrosion on SiO2-TiO2-ZrO2 coatings synthesized by the sol-gel method

    Science.gov (United States)

    Bautista Ruiz, J.; Aperador, W.; Caballero Gómez, J.

    2016-02-01

    The medical science and the engineering, work to improve the materials used in the manufacture of joint implants, since they have a direct impact on the quality of people life. The surgical interventions are increasing worldwide with a high probability of a second or even a third intervention. Around these circumstances, it was evaluated the behaviour against microabrasion-corrosion phenomena on SiO2 TiO2 ZrO2 coatings, synthesized by the sol-gel method with concentration of the Si/Ti/Zr precursors: 10/70/20 and 10/20/70. The coatings were deposited on AISI 316 LVM stainless steel substrates. The morphological characterization of the wear was made by AFM techniques. It was observed that the coatings with higher levels of titanium have a good response to the phenomena of microabrasion-corrosion.

  6. O2 depletion in granitic media. The Rex project

    International Nuclear Information System (INIS)

    Puigdomenech, I.; Ambrosi, J.P.; Eisenlohr, L.; Lartigue, J.E.; Banwart, S.A.; Bateman, K.; Milodowski, A.E.; West, J.M.; Griffault, L.; Gustafsson, E.; Hama, K.; Yoshida, H.; Michaud, V.; Trotignon, L.; Rivas Perez, J.; Tullborg, E.L.

    2001-02-01

    The redox conditions are of consequence for the performance of nuclear repositories. The presence of molecular oxygen (O 2 ) would affect the corrosion of canisters and the migration of radionuclides eventually released from a damaged canister. The rate of disappearance of O 2 left in voids at repository closure is therefore an important information when evaluating repository designs. The REX project (Redox Experiment in Detailed Scale) has been carried out within the frame of SKB Aespoe Hard Rock Laboratory in Sweden. The aim was to determine how O 2 trapped in the closed repository would react with the rock minerals in the tunnel and deposition holes and in the water conducting fractures. The REX project consisted of the following sections: Field investigations at Aespoe: Microbial O 2 consumption at several sites in the Aespoe tunnel. The in situ experiment: Injection of oxygen and monitoring of O 2 uptake in a confined fracture surface. The Replica Experiment: a laboratory study using the other half of the fracture surface used for the in situ experiment. Laboratory experiments: needed to support the interpretation of the field and replica experiments. Conducted with groundwaters, bacteria, and mineral samples from Aespoe. The results from the in-situ experiment were confirmed by those of the replica experiment performed in the CEA laboratory in France. Both were concordant in showing time scales for O 2 uptake in the order of days. The agreement was remarkable when taking into account the differences in experimental conditions. For example, different microbial processes took place in the two experiments. Laboratory studies with rock samples demonstrated that microbial activity induced increased chemical weathering, with the formation of clay minerals. Rates of O 2 uptake by fracture filling minerals were determined under laboratory conditions. These rates were faster than those reported in literature studies of pure mineral systems, and supported the fast O 2

  7. Singlet oxygen generation in O2 flow excited by RF discharge: I. Homogeneous discharge mode: α-mode

    International Nuclear Information System (INIS)

    Braginskiy, O V; Vasilieva, A N; Klopovskiy, K S; Kovalev, A S; Lopaev, D V; Proshina, O V; Rakhimova, T V; Rakhimov, A T

    2005-01-01

    2 (a 1 Δ g ) production by direct electron impact and loss owing to quenching by the tube walls at a low pressure below 4 Torr, as well as by three-body recombination with oxygen atoms with increasing pressure above 7 Torr. The analysis of O 2 (a 1 Δ g ) three-body quenching by oxygen atoms showed that this process could actually have a high rate constant and be able to provide a fast SO deactivation at high pressures. The approximate value of the rate constant-(1-3) x 10 -32 cm 3 s -1 has been obtained from the best agreement between the simulated and experimental data on transport dynamics of O 2 (a 1 Δ g ) molecules and O( 3 P) atoms. It is shown that the RF discharge α-mode corresponds to a discharge with an effective reduced electrical field in a quasi-neutral plasma of about ∼ 30 Td, which makes possible a rather high efficiency of SO production of ∼ 3-5%

  8. Uptake of TiO2 Nanoparticles into C. elegans Neurons Negatively Affects Axonal Growth and Worm Locomotion Behavior.

    Science.gov (United States)

    Hu, Chun-Chih; Wu, Gong-Her; Hua, Tzu-En; Wagner, Oliver I; Yen, Ta-Jen

    2018-03-14

    We employ model organism Caenorhabditis elegans to effectively study the toxicology of anatase and rutile phase titanium dioxide (TiO 2 ) nanoparticles (NPs). The experimental results show that nematode C. elegans can take up fluorescein isothiocyanate-labeled TiO 2 NPs and that both anatase and rutile TiO 2 NPs can be detected in the cytoplasm of cultured primary neurons imaged by transmission electron microscopy. After TiO 2 NP exposure, these neurons also grow shorter axons, which may be related to the detected impeded worm locomotion behavior. Furthermore, anatase TiO 2 NPs did not affect the worm's body length; however, we determined that a concentration of 500 μg/mL of anatase TiO 2 NPs reduced the worm population by 50% within 72 h. Notably, rutile TiO 2 NPs negatively affect both the body size and worm population. Worms unable to enter the L4 larval stage explain a severe reduction in the worm population at TiO 2 NPs LC 50 /3d. To obtain a better understanding of the cellular mechanisms involved in TiO 2 NP intoxication, DNA microarray assays were employed to determine changes in gene expression in the presence or absence of TiO 2 NP exposure. Our data reveal that three genes (with significant changes in expression levels) were related to metal binding or metal detoxification (mtl-2, C45B2.2, and nhr-247), six genes were involved in fertility and reproduction (mtl-2, F26F2.3, ZK970.7, clec-70, K08C9.7, and C38C3.7), four genes were involved in worm growth and body morphogenesis (mtl-2, F26F2.3, C38C3.7, and nhr-247), and five genes were involved in neuronal function (C41G6.13, C45B2.2, srr-6, K08C9.7, and C38C3.7).

  9. Analysis of Vertical Weighting Functions for Lidar Measurements of Atmospheric CO2 and O2

    Science.gov (United States)

    Kooi, S.; Mao, J.; Abshire, J. B.; Browell, E. V.; Weaver, C. J.; Kawa, S. R.

    2011-12-01

    Several NASA groups have developed integrated path differential absorption (IPDA) lidar approaches to measure atmospheric CO2 concentrations from space as a candidates for NASA's ASCENDS space mission. For example, the Goddard CO2 Sounder approach uses two pulsed lasers to simultaneously measure both CO2 and O2 absorption in the vertical path to the surface at a number of wavelengths across a CO2 line near 1572 nm and an O2 line doublet near 764 nm. The measurements of CO2 and O2 absorption allow computing their vertically weighted number densities and then their ratios for estimating CO2 concentration relative to dry air. Since both the CO2 and O2 densities and their absorption line-width decrease with altitude, the absorption response (or weighting function) varies with both altitude and absorption wavelength. We have used some standard atmospheres and HITRAN 2008 spectroscopy to calculate the vertical weighting functions for two CO2 lines near 1571 nm and the O2 lines near 764.7 and 1260 nm for candidate online wavelength selections for ASCENDS. For CO2, the primary candidate on-line wavelengths are 10-12 pm away from line center with the weighting function peaking in the atmospheric boundary layer to measure CO2 sources and sinks at the surface. Using another on-line wavelength 3-5 pm away from line center allows the weighting function to peak in the mid- to upper troposphere, which is sensitive to CO2 transport in the free atmosphere. The Goddard CO2 sounder team developed an airborne precursor version of a space instrument. During the summers of 2009, 2010 and 2011 it has participated in airborne measurement campaigns over a variety of different sites in the US, flying with other NASA ASCENDS lidar candidates along with accurate in-situ atmospheric sensors. All flights used altitude patterns with measurements at steps in altitudes between 3 and 13 km, along with spirals from 13 km altitude to near the surface. Measurements from in-situ sensors allowed an

  10. O2 uptake kinetics during exercise at peak O2 uptake.

    Science.gov (United States)

    Scheuermann, Barry W; Barstow, Thomas J

    2003-11-01

    Compared with moderate- and heavy-intensity exercise, the adjustment of O2 uptake (VO2) to exercise intensities that elicit peak VO2 has received relatively little attention. This study examined the VO2 response of 21 young, healthy subjects (25 +/- 6 yr; mean +/- SD) during cycle ergometer exercise to step transitions in work rate (WR) corresponding to 90, 100, and 110% of the peak WR achieved during a preliminary ramp protocol (15-30 W/min). Gas exchange was measured breath by breath and interpolated to 1-s values. VO2 kinetics were determined by use of a two- or three-component exponential model to isolate the time constant (tau2) as representative of VO2 kinetics and the amplitude (Amp) of the primary fast component independent of the appearance of any VO2 slow component. No difference in VO2 kinetics was observed between WRs (tau90 = 24.7 +/- 9.0; tau100 = 22.8 +/- 6.7; tau110 = 21.5 +/- 9.2 s, where subscripts denote percent of peak WR; P > 0.05); nor in a subgroup of eight subjects was tau2 different from the value for moderate-intensity (exercise (tau2 = 25 +/- 12 s, P > 0.05). As expected, the Amp increased with increasing WRs (Amp90 = 2,089 +/- 548; Amp100 = 2,165 +/- 517; Amp110 = 2,225 +/- 559 ml/min; Amp90 vs. Amp110, P exercise, the gain of the Vo2 response (as deltaVO2/DeltaWR) is reduced for exercise transitions in the severe-intensity domain, but the approach to this gain is well described by a common time constant that is invariant across work intensities. The lower deltaVO2/deltaWR may be due to an insufficient adjustment of the cardiovascular and/or pulmonary systems that determine O2 delivery to the exercising muscles or due to recruitment of motor units with lower oxidative capacity, after the onset of exercise in the severe-intensity domain.

  11. PULSE COLUMN

    Science.gov (United States)

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  12. Pulse radiolysis

    International Nuclear Information System (INIS)

    Greenshields, H.; Seddon, W.A.

    1982-03-01

    This supplement to two bibliographies published in 1970 and 1972 lists 734 references to the literature of pulse radiolysis, arranged under eight broad subject headings. The references were compiled by searching Biological Abstracts, Chemical Abstracts, Nuclear Science Abstracts and the Weekly List of Papers in Radiation Chemistry issued by the Radiation Chemistry Data Center of Notre Dame University. Full bibliographic data is given for papers published in the period 1971 to 1974. A personal author index listing more than 600 authors and a similar number of co-authors is included

  13. Degradation of Pentachlorophenol in Aqueous Solution by the UV/ZrO 2 /H 2 O 2 Photocatalytic Process

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Samarghandi

    2015-12-01

    Full Text Available Pentachlorophenol (PCP, which is one of the resistant phenolic compounds, has been classified in the category of EPA’s priority pollutants due to its high toxicity and carcinogenic potential. Therefore, its removal from water and wastewater is very important. Various methods have been studied for removing the compound, among which advanced oxidation processes (AOPs have attracted much attention because of ease of application and high efficiency. Thus the aim of this study was to investigate the efficiency of the UV/ZrO2/H2O2 process, as an AOP, for PCP removal from aquatic environments. The effects of several parameters such as ultraviolet (UV exposure time, initial PCP concentration, pH, concentration of zirconium dioxide (ZrO2 nanoparticles, and H2O2 concentration were studied. Kinetics of the reaction was also detected. The concentration of the stated materials in the samples was determined using a spectrophotometer at 500 nm. The results showed that the highest efficiency (approximately 100% was reached at optimized conditions of pH 6, contact time of 30 minutes, initial PCP concentration of 20 mg/L, the nanoparticles concentration of 0.1 g/L and H2O2 concentration of 14.7 mM/L. Also, the process followed the first order kinetics reaction. The obtained results illustrated that the UV/ZrO2/H2O2 process has a high ability in removing PCP.

  14. Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2

    Science.gov (United States)

    Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.

    2013-01-01

    We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.

  15. High-Performance Na-O2 Batteries Enabled by Oriented NaO2 Nanowires as Discharge Products.

    Science.gov (United States)

    Khajehbashi, S Mohammad B; Xu, Lin; Zhang, Guobin; Tan, Shuangshuang; Zhao, Yan; Wang, Lai-Sen; Li, Jiantao; Luo, Wen; Peng, Dong-Liang; Mai, Liqiang

    2018-06-13

    Na-O 2 batteries are emerging rechargeable batteries due to their high theoretical energy density and abundant resources, but they suffer from sluggish kinetics due to the formation of large-size discharge products with cubic or irregular particle shapes. Here, we report the unique growth of discharge products of NaO 2 nanowires inside Na-O 2 batteries that significantly boosts the performance of Na-O 2 batteries. For this purpose, a high-spin Co 3 O 4 electrocatalyst was synthesized via the high-temperature oxidation of pure cobalt nanoparticles in an external magnetic field. The discharge products of NaO 2 nanowires are 10-20 nm in diameter and ∼10 μm in length, characteristics that provide facile pathways for electron and ion transfer. With these nanowires, Na-O 2 batteries have surpassed 400 cycles with a fixed capacity of 1000 mA h g -1 , an ultra-low over-potential of ∼60 mV during charging, and near-zero over-potential during discharging. This strategy not only provides a unique way to control the morphology of discharge products to achieve high-performance Na-O 2 batteries but also opens up the opportunity to explore growing nanowires in novel conditions.

  16. Plasma-assisted adsorption of elemental mercury on CeO2/TiO2 at low temperatures

    Science.gov (United States)

    Liu, Lu; Zheng, Chenghang; Gao, Xiang

    2017-11-01

    Mercury is a kind of pollutants contained in flue gas which is hazardous for human beings. In this work, CeO2 was packed in the discharge zone of a plasma reactor to adsorb elemental mercury at low temperatures. Plasma-catalyst reactor can remove Hg0 efficiently with CeO2/TiO2 catalysts packed in the discharge zone. The Hg0 concentration continued to decrease gradually when the plasma was turned on, but not sank rapidly. This tendency was different with other catalysts. The treatment of plasma to CeO2/TiO2 catalysts has a promotion effect on the adsorption of Hg0. Plasma has the effect of changing the surface properties of the catalysts and the changes would restitute if the condition changed. The long-running test demonstrated that this method is an effective way to remove Hg0. The removal efficiency remained at above 99% throughout 12 hours when plasma had been turned on (15kV, 0.5 g packed CeO2/TiO2).

  17. Fabrication and photocatalytic activity of high-efficiency visible-light-responsive photocatalyst ZnTe/TiO2 nanotube arrays

    International Nuclear Information System (INIS)

    Liu Yutang; Zhang Xilin; Liu Ronghua; Yang Renbin; Liu Chengbin; Cai Qingyun

    2011-01-01

    A new ZnTe modified TiO 2 nanotube (NT) array catalyst was prepared by pulse potential electrodeposition of ZnTe nanoparticles (NPs) onto TiO 2 NT arrays, and its application for photocatalytic degradation of anthracene-9-carboxylic acid (9-AnCOOH) was investigated. The even distribution of ZnTe NPs was well-proportionately grown on the top surface of the TiO 2 NT while without clogging the tube entrances. Compared with the unmodified TiO 2 NT, the ZnTe modified TiO 2 NT (ZnTe/TiO 2 NT) showed significantly enhanced photocatalytic activity towards 9-AnCOOH under simulated solar light. After 70 min of irradiation, 9-AnCOOH was degraded with the removal ratio of 45% on the bare TiO 2 NT, much lower than 80%, 90%, and 100% on the ZnTe/TiO 2 NT with the ZnTe NPs prepared under the pulsed 'on' potentials of -0.8, -1.0, and -2.0 V, respectively. The increased photodegradation efficiency mainly results from the improved photocurrent density as results of enhanced visible-light absorption and decreased hole-electron recombination due to the presence of narrow-band-gap p-type semiconductor ZnTe. -- Graphical abstract: Surface-view SEM images of ZnTe/TiO 2 NT prepared under -2.0 V, and the inset is the corresponding enlarged drawings. Display Omitted Research highlights: → A new method to deposit chalcogenides of transition metals on the TiO 2 nanotubes. → The even distribution of ZnTe nanoparticles was well-proportionedly grown onto TiO 2 NT arrays. → ZnTe/TiO 2 NT showed remarkably increased photocurrent density. → ZnTe/TiO 2 NT showed good photocatalytic performance. → The prepared new catalyst has a promising application in practical systems.

  18. Epitaxial TiO 2/SnO 2 core-shell heterostructure by atomic layer deposition

    KAUST Repository

    Nie, Anmin

    2012-01-01

    Taking TiO 2/SnO 2 core-shell nanowires (NWs) as a model system, we systematically investigate the structure and the morphological evolution of this heterostructure synthesized by atomic layer deposition/epitaxy (ALD/ALE). All characterizations, by X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction and Raman spectra, reveal that single crystalline rutile TiO 2 shells can be epitaxially grown on SnO 2 NWs with an atomically sharp interface at low temperature (250 °C). The growth behavior of the TiO 2 shells highly depends on the surface orientations and the geometrical shape of the core SnO 2 NW cross-section. Atomically smooth surfaces are found for growth on the {110} surface. Rough surfaces develop on {100} surfaces due to (100) - (1 × 3) reconstruction, by introducing steps in the [010] direction as a continuation of {110} facets. Lattice mismatch induces superlattice structures in the TiO 2 shell and misfit dislocations along the interface. Conformal epitaxial growth has been observed for SnO 2 NW cores with an octagonal cross-section ({100} and {110} surfaces). However, for a rectangular core ({101} and {010} surfaces), the shell also derives an octagonal shape from the epitaxial growth, which was explained by a proposed model based on ALD kinetics. The surface steps and defects induced by the lattice mismatch likely lead to improved photoluminescence (PL) performance for the yellow emission. Compared to the pure SnO 2 NWs, the PL spectrum of the core-shell nanostructures exhibits a stronger emission peak, which suggests potential applications in optoelectronics. © The Royal Society of Chemistry 2012.

  19. Reliability of pulse oximetry during cardiopulmonary resuscitation in a piglet model of neonatal cardiac arrest.

    Science.gov (United States)

    Hassan, Mohammad Ahmad; Mendler, Marc; Maurer, Miriam; Waitz, Markus; Huang, Li; Hummler, Helmut D

    2015-01-01

    Pulse oximetry is widely used in intensive care and emergency conditions to monitor arterial oxygenation and to guide oxygen therapy. To study the reliability of pulse oximetry in comparison with CO-oximetry in newborn piglets during cardiopulmonary resuscitation (CPR). In a prospective cohort study in 30 healthy newborn piglets, cardiac arrest was induced, and thereafter each piglet received CPR for 20 min. Arterial oxygen saturation was monitored continuously by pulse oximetry (SpO2). Arterial blood was analyzed for functional oxygenation (SaO2) every 2 min. SpO2 was compared with coinciding SaO2 values and bias considered whenever the difference (SpO2 - SaO2) was beyond ±5%. Bias values were decreased at the baseline measurements (mean: 2.5 ± 4.6%) with higher precision and accuracy compared with values across the experiment. Two minutes after cardiac arrest, there was a marked decrease in precision and accuracy as well as an increase in bias up to 13 ± 34%, reaching a maximum of 45.6 ± 28.3% after 10 min over a mean SaO2 range of 29-58%. Pulse oximetry showed increased bias and decreased accuracy and precision during CPR in a model of neonatal cardiac arrest. We recommend further studies to clarify the exact mechanisms of these false readings to improve reliability of pulse oximetry during the marked desaturation and hypoperfusion found during CPR. © 2014 S. Karger AG, Basel.

  20. Pulse pile-up. I: Short pulses

    International Nuclear Information System (INIS)

    Wilkinson, D.H.

    1990-07-01

    The search for rare large pulses against an intense background of smaller ones involves consideration of pulse pile-up. Approximate methods are presented, based on ruin theory, by which the probability of such pile-up may be estimated for pulses of arbitrary form and of arbitrary pulse-height distribution. These methods are checked against cases for which exact solutions are available. The present paper is concerned chiefly with short pulses of finite total duration. (Author) (5 refs., 24 figs.)