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Sample records for ni eikyo wo

  1. Hydrothermal synthesis of NiWO4 crystals for high performance non-enzymatic glucose biosensors

    Science.gov (United States)

    Mani, Sivakumar; Vediyappan, Veeramani; Chen, Shen-Ming; Madhu, Rajesh; Pitchaimani, Veerakumar; Chang, Jia-Yaw; Liu, Shang-Bin

    2016-01-01

    A facile hydrothermal route for the synthesis of ordered NiWO4 nanocrystals, which show promising applications as high performance non-enzymatic glucose sensor is reported. The NiWO4-modified electrodes showed excellent sensitivity (269.6 μA mM−1 cm−2) and low detection limit (0.18 μM) for detection of glucose with desirable selectivity, stability, and tolerance to interference, rendering their prospective applications as cost-effective, enzyme-free glucose sensors. PMID:27087561

  2. Effects of heat treatment on toughness of austempered ductile cast iron with Cu and Ni; Cu-Ni tenka osutenpa chutetsu no jinsei ni oyobosu netsushori no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Aoyama, M.; Takatsu, M.; Takagi, H

    1998-08-25

    The alloying of ductile cast iron with Cu and Ni is effective for the structural control in austemper heat treatment. Use of this type of cast iron is provided to produce cast iron materials with extremely high toughness and strength. In this study, the effects of austempering conditions and the addition of Cu and Ni on toughness of ductile cast iron are investigated. In austemper heat treatment, impact absorbed energy is increased by raising the austempering temperature. However, at high austempering temperatures exceeding 3.6 ks at 673K, the formation of fine pearlite proceeded, resulting in a marked decrease in the impact absorbed energy. Addition of Cu-Ni in the cast iron resulted in greater impact absorbed energy and tensile strength at any temperature during the austempering treatment. It depends on the suppression of precipitation beginning of fine pearlite and the stabilization of retained austenite. Furthermore, this cast iron alloy reduced the change in impact absorbed energy and tensile strength, induced during the austempering time. 15 refs., 12 figs., 1 tab.

  3. Magnetic behavior of Ca{sub 2}NiWO{sub 6} double perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, C.A. [Area de Quimica General e Inorganica ' Dr. G.F.Puelles' , Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); Curiale, J. [Centro Atomico Bariloche and Instituto Balseiro (UNCuyo), CNEA, Av. Bustillo 9500 (R8402AGP) S. C. de Bariloche, RN (Argentina); Viola, M. del C. [Area de Quimica General e Inorganica ' Dr. G.F.Puelles' , Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); Pedregosa, J.C. [Area de Quimica General e Inorganica ' Dr. G.F.Puelles' , Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina)]. E-mail: jpedreg@unsl.edu.ar; Sanchez, R.D. [Centro Atomico Bariloche and Instituto Balseiro (UNCuyo), CNEA, Av. Bustillo 9500 (R8402AGP) S. C. de Bariloche, RN (Argentina)]. E-mail: rodo@cab.cnea.gov.ar

    2007-09-01

    Polycrystalline Ca{sub 2}NiWO{sub 6} double perovskite has been prepared by solid-state reaction at 1150 C. The crystal structure of this material has been confirmed by X-ray powder diffraction (XRD). At room temperature, the crystal structure is monoclinic, space group P2{sub 1}/n, with a=5.4061(2) A, b=5.5389(2) A, c=7.6895(3) A, {beta}=90.232(2){sup o}. Magnetic susceptibility and electron spin resonance experiments on Ca{sub 2}NiWO{sub 6} show at high temperature a Curie-Weiss behavior with a {theta}=-75 K. From the Curie-Weiss behavior, the effective magnetic moment is 2.85{mu} {sub B}, which is in agreement with the presence of Ni{sup 2+} in the system. At low temperatures, below 52.5(0.2) K, the magnetic susceptibility shows antiferromagnetic behavior. From the experimental data and the mean field theory of antiferromagnetism we estimated the Ni interactions among the nearest Ni neighbors and the second nearest Ni neighbors.

  4. Lattice and spin dynamics in a low-symmetry antiferromagnet NiWO4

    Science.gov (United States)

    Prosnikov, M. A.; Davydov, V. Yu.; Smirnov, A. N.; Volkov, M. P.; Pisarev, R. V.; Becker, P.; Bohatý, L.

    2017-07-01

    Lattice and magnetic dynamics of NiWO4 single crystals were studied with the use of polarized Raman spectroscopy in a wide temperature range of 10-300 K including the antiferromagnetic ordering temperature TN=62 K. Static magnetic measurements were used for characterizing the single crystals. All Raman-active phonons predicted by the group theory were observed and characterized. Magnetic symmetry analysis was used to determine possible magnetic space groups for NiWO4 which can be also applied to any other isostructural crystal with the same magnetic propagation vector k =(1 /2 ,0 ,0 ) . Although the magnetic structure of NiWO4 is relatively simple, a rich set of narrow and broad magnetic excitations with different polarization properties and temperature behavior in the very broad frequency range of 10-200 cm-1 was observed, with some modes surviving at temperatures much higher than TN up to 220 K. Part of the magnetic excitations were identified as acoustic and optical spin-wave branches which allowed us to construct exchange structure and estimate exchange and anisotropy constants with the use of linear spin-wave theory.

  5. Laminated all-solid state NiO/WO3 complementary electrochromic device

    Institute of Scientific and Technical Information of China (English)

    胡行方; 陈晓峰; 李智勇; 高濂; 严东生

    1997-01-01

    Based on the previous studies on the rf reactive sputtered nickel oxide film with nanostructure and its electrochromism, i. e. electrochromic effect of the films is attributed to the reversible change of the non-stoichiometry in the nanocrystaltine gram boundaries and interfaces due to the injection and ejection of Li+ ions, a prototype of all-solid-state NiO/WO3 complementary electrochromic device using LixTaOy thin film as inorganic electrolyte was designed and prepared. The results indicate that the solar reflectance of the device could be modulated from 0. 15 in colored state to 0.60 in bleached state with excellent cyclic reversibility, durability and high response speed (less than 0.3 s from colored state to bleached state).

  6. Influence of catalytic activity and reaction conditions on the product distribution in coal liquefaction; Sekitan ekikayu no seiseibutsu bunpu ni taisuru shokubai kassei oyobi hanno joken no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Hasuo, H.; Sakanishi, K.; Mochida, I. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    1996-10-28

    The NiMo sulfide supported on Ketjen Black (KB) was more effective and yielded lighter oil products containing light fractions with their boiling point below 300{degree}C during the two stage liquefaction combining low temperature and high temperature hydrogenation the conventional NiMo/alumina catalyst and FeS2 catalyst. Although the NiMo/alumina yielded increased oil products during the two stage liquefaction, the lighter oil fractions did not increase and the heavier fractions increased mainly. This suggests that the hydrogenation of aromatic rings and successive cleavage of the rings are necessary for producing the light oil, which is derived from the sufficient hydrogenation of aromatic rings using catalysts. For the two stage reaction with NiMo/KB catalyst, it was considered that sufficient hydrogen was directly transferred to coal molecules at the first stage of the low temperature reaction, which promoted the solubilization of coal and the successive hydrogenation at the high temperature reaction. Thus, high activity of the catalyst must be obtained. It is expected that further high quality distillates can be produced through the optimization of catalysts and solvents at the two stage reaction. 1 ref., 4 figs., 1 tab.

  7. Electrochromic properties of NiOx:H films deposited by DC magnetron sputtering for ITO/NiOx:H/ZrO2/WO3/ITO device

    Science.gov (United States)

    Dong, Dongmei; Wang, Wenwen; Dong, Guobo; Zhou, Yuliang; Wu, Zhonghou; Wang, Mei; Liu, Famin; Diao, Xungang

    2015-12-01

    NiOx:H thin films were deposited on ITO-coated glass by DC reactive magnetron sputtering at room temperature. The effects of the hydrogen content on the structure, morphologies, electrochemical properties, the stoichiometry and chemical states of NiOx:H thin films were systematically studied. In X-ray diffraction and atomic force microscopy analysis, the crystallinity of the films tends to be weakened when the flow amount ratio of Ar:O2:H2 equals 19:1:3 and as confirmed in electrochemical analysis, such relatively weak crystallinity is the main contributing factor to ion transportation. X-ray photoelectron spectroscopy reveals that the increase of the hydrogen contents results in a relatively lower binding energy exhibited in the Ni 2p spectra. The proportion of Ni2O3 in NiOx:H films increases from 22% at bleached state to 33% at colored state. A monolithic all-thin-film inorganic electrochromic device was fabricated with complementary configuration as ITO/NiOx:H/ZrO2/WO3/ITO. The electrochromic device with optimized NiOx:H thin films acting both as ion storage layer and proton-providing source displays high modulation efficiency of 68% at a fixed wavelength 550 nm.

  8. Unsupported NiPt alloy metal catalysts prepared by water-in-oil (W/O) microemulsion method for methane cracking

    KAUST Repository

    Zhou, Lu

    2016-05-18

    Unsupported NiPt metal catalyst with Ni/Pt molar ratio of 88/12 is prepared by water-in-oil (W/O) microemulsion method in this study. Compared to monometallic Ni and Pt catalysts, the NiPt catalyst exhibits superior activity and stability for methane cracking. By XRD (X-ray powder diffraction), XPS (X-ray photoelectron spectroscopy) and TEM (Transmission electron microscopy) analyses, the formation of Ni(0)Pt(0) alloy is believed to be the main reason for the reactivity improvement of this catalyst. Carbon nano tube (CNT) with Ni(0)Pt(0) particles anchored on the top of tube are found for the NiPt catalyst. © 2016 Elsevier Ltd.

  9. Effect of hydrogen on transformation characteristics and deformation behavior in a TiNi shape memory alloy. Ti-Ni kei keijo kioku gokin no hentai tokusei oyobi henkei kyodo ni oyobosu suiso no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yoshiya, T.; Katsuta, H.; Ando, H. (Japan Atomic Energy Research Institute, Tokyo (Japan)); Den, S. (Irie Koken Co. Ltd., Saitama (Japan))

    1992-07-20

    Transformation characteristics and deformation behavior of Ti-50.5at%Ni shape memory alloys, which were occluded hydrogen in various levels, were investigated through electrical resistivity measurements, tensile tests, and X-ray diffraction. Specimens were heated in a low pressure range of hydrogen between 1.1 and 78.5kPa for equilibrium, and thus obtained the specimen which occluded hydrogen up to a maximum value of 5.6 mol%. Martensitic transformation starting temperature(Ms) decreased with an increase in hydrogen content. This corresponds to the fact that the improvement of stabilization of the parent phase during cooling due to hydrogen occlusion was confirmed by X-ray diffraction. It also shows that hydrogen has the suppression effect on this deformation. Critical stress for slip deformation changed with hydrogen content so that hydrogen influenced greatly on deformation behavior of the alloys. Lattice softening occurred with hydrogen contents up to 0.032 mol%, and changed into hardening above 0.032 mol%. Hydrides formed with hydrogen contents over 1.9 mol% resulted in reorientation in variants of the R phase and an increase in lattice strains of the parent phase. 29 refs., 14 figs., 1 tab.

  10. Effect of quenching rate on martensitic transformation temperature in Cu-Al-Ni shape memory alloys; Cu-Al-Ni keijo kioku gokin no maltensite hentai ondo ni oyobosu yakiire reikyakusokudo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Nakaniwa, M.; Sugimoto, K.; Kamei, K.; Nakamura, Y.; Sugimoto, T. [Kansai University, Osaka (Japan). Faculty of Engineering

    1995-08-20

    Experiments were carried out for Cu-xAl-5Ni-2Mn-1Ti shape memory alloys (x= 11.45, 11.77, 11.88 mass%) in order to examine the effect of quenching rate on the transformation temperatures (Ms, Mf, As and Af). The quenching rate was varied from 5 to 1{times}10{sup 4} K/s by changing the temperature of quenching media. The transformation temperatures were determined by DSC measurements for all the samples quenched and are plotted as a faction of quenching rate. It was found that all the transformation temperatures decreased by about 10 K, when the quenching rate was increased 10 times as large as its initial value. The reason was explained by considering the degree of order in the beta-phase. The primary {alpha}- and {gamma}2-phases do not precipitate even during air-cooling on quenching in the alloys with 11.77 and 11.88%Al, being close to the eutectoid composition. Therefore, no remarkable change in martensitic transformation temperature with reducing quenching rate was observed in these alloys. In other words, it can be concluded that these alloys are suitable for heat treatments in practice, where the specimens are cooled more slowly. 20 refs., 5 figs., 2 tabs.

  11. Preparation and properties of all-solid-state inorganic thin film glass/ITO/WO3/LiNbO3/NiOx/ITO electrochromic device

    Science.gov (United States)

    Wu, Zhonghou; Diao, Xungang; Dong, Guobo

    2016-01-01

    The all-thin-film inorganic electrochromic device (ECD) with LiNbO3 as the ion conductor layer was prepared. The ECD was fabricated monolithically in a same vacuum chamber layer by layer using DC reactive sputtering for WO3, NiOx and ITO, and radio frequency (RF) sputtering for LiNbO3. The properties and performance of WO3 thin film and the ECD were studied through X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible spectrometry. WO3 thin film has more than 60% optical modulation with porous amorphous structure. The visible transmittance modulation of the ECD is more than 65%, and the response time of coloring and bleaching are 45 s and 25 s, respectively.

  12. Effect of WO{sub x} on Co and Ni/Hydrotalcite catalysts to obtain hydrogen from bioethanol; Efecto del WO{sub x} sobre catalizadores de Co, Ni/hidrotalcita para obtener hidrogeno a partir de bioetanol

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, M.A.; Contreras, J. L. [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D.F. (Mexico)]. E-mail: jlcl@correo.azc.uam.mx; Fuentes, G.A. [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D.F. (Mexico); Luna, R. [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D.F. (Mexico); Salmones, J.; Zeifert, B. [ESIQIE, Instituto Politecnico Nacional, Mexico, D.F. (Mexico)] Vazquez, A. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)

    2009-09-15

    . Se encontro una morfologia de poros en forma de placas paralelas y un area entre 150-250 m{sup 2}/g, con una distribucion mesoporosa (bimodal). Por infrarrojo se encontraron vibraciones de OH, H{sub 2}O, Al-OH, Mg-OH y CO32-, tambien un pico de baja intensidad relacionado a las vibraciones de tipo W=O. Por Raman se encontraron enlaces del tipo W-O-W. Por UV-vis se encontro una banda en la region ultravioleta, que en el caso de la serie de cobalto, disminuye conforme aumenta el contenido de W. El caso contrario ocurrio para la serie de Ni. Se observo que el W promueve la conversion en la serie de Co hasta un 80% mientras que no la promueve en el caso del Ni. Se demostro que el W promueve la estabilidad catalitica (despues de 430 min), la serie de Co mostro una conversion de 80% y la de Ni llego al 90%, Ningun catalizador se desactivo antes de 350 min.

  13. All-Solid-Thin Film Electrochromic Devices Consisting of Layers ITO / NiO / ZrO2 / WO3 / ITO

    Directory of Open Access Journals (Sweden)

    K.J. Patel

    2013-05-01

    Full Text Available We have prepared an all-solid-thin film electrochromic device (ECD, consisting of layers ITO / NiO / ZrO2 / WO3 / ITO using the PVD method. The WO3 is used as an electrochromic layer, NiO as an ion-storage layer, and ZrO2 as a solid electrolyte layer in the all-solid-thin film ECD. The optical transmittance varied between 3-59 %. The device shows the coloration and bleaching time of 120 s and 2 s, respectively, with a good memory effect and desirable cycle-life.

  14. Inkjet-printed all solid-state electrochromic devices based on NiO/WO3 nanoparticle complementary electrodes

    Science.gov (United States)

    Cai, Guofa; Darmawan, Peter; Cui, Mengqi; Chen, Jingwei; Wang, Xu; Eh, Alice Lee-Sie; Magdassi, Shlomo; Lee, Pooi See

    2015-12-01

    Nanostructured thin films are important in the fields of energy conversion and storage. In particular, multi-layered nanostructured films play an important role as a part of the energy system for energy saving applications in buildings. Inkjet printing is a low-cost and attractive technology for patterning and deposition of multi-layered nanostructured materials on various substrates. However, it requires the development of a suitable ink formulation with optimum viscosity, surface tension and evaporation rate for various materials. In this study, a versatile ink formulation was successfully developed to prepare NiO and WO3 nanostructured films with strong adhesion to ITO coated glass using inkjet printing for energy saving electrochromic applications. We achieved a high performance electrochromic electrode, producing porous and continuous electrochromic films without aggregation. The NiO film with 9 printed layers exhibits an optical modulation of 64.2% at 550 nm and a coloration efficiency (CE) of 136.7 cm2 C-1. An inkjet-printed complementary all solid-state device was assembled, delivering a larger optical modulation of 75.4% at 633 nm and a higher CE of 131.9 cm2 C-1 among all solid-state devices. The enhanced contrast is due to the printed NiO film that not only performs as an ion storage layer, but also as a complementary electrochromic layer.Nanostructured thin films are important in the fields of energy conversion and storage. In particular, multi-layered nanostructured films play an important role as a part of the energy system for energy saving applications in buildings. Inkjet printing is a low-cost and attractive technology for patterning and deposition of multi-layered nanostructured materials on various substrates. However, it requires the development of a suitable ink formulation with optimum viscosity, surface tension and evaporation rate for various materials. In this study, a versatile ink formulation was successfully developed to prepare NiO and

  15. NiWO4-ZnO-NRGO ternary nanocomposite as an efficient photocatalyst for degradation of methylene blue and reduction of 4-nitro phenol

    Science.gov (United States)

    Sadiq, M. Mohamed Jaffer; Shenoy, U. Sandhya; Bhat, D. Krishna

    2017-10-01

    A novel NiWO4-ZnO-NRGO ternary nanocomposite has been efficiently synthesized by decorating nitrogen doped reduced graphene oxide (NRGO) with zinc oxide and nickel tungstate nanoparticles via a facile microwave irradiation technique and its capability to catalyze photodegradation of methylene blue (MB) dye in aqueous solution and reduction of 4-nitro phenol (4-NP) to 4-amino phenol (4-AP) using sodium borohydride was explored. The as-synthesized nanocomposite was characterized by X-ray diffraction (XRD), Raman spectroscopy, Brunauer-Emmett-Teller (BET) analysis, energy dispersive X-ray (EDX) analysis, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and diffuse reflectance spectroscopy (DRS) techniques. The photocatalytic activity of the as-synthesized nanocomposite estimated through the photodegradation of MB under visible light irradiation showed 9 times improvement over pure NiWO4. It also showed excellent catalytic activity in reduction of 4-NP to 4-AP. The material also showed excellent stability and reusability. The entire study revealed that the novel NiWO4-ZnO-NRGO ternary nanocomposite can act as a promising bifunctional photocatalyst for environmental remediation and industrial application.

  16. Stress releasement by transformation superplasticity. Part 2. ; Effect of alloying elements and transformation temperature on stress releasement. Hentai chososei ni yoru oryoku kanwa. 2. ; Oryoku kanwa ni oyobosu gokin genso oyobi hentai ondo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Murata, H. (Yokogawa Medical System, Ltd., Tokyo (Japan)); Kato, N. (Tokyo Institute of Technology, Tokyo (Japan)); Tamura, H. (Nihon University, Tokyo (Japan))

    1991-02-05

    Steel test pieces having various transformation temperatures (M {sub S}) were fabricated varying Ni and Cr contents, and tests were done on their torsional transformation resistance in cooling process, and stress relaxing characteristics due to transformation superplasticity, using a forced twisting equipment. The test pieces, while being twisted, were heated by high frequency induction from an external source to 1000 {degree} C in 50 seconds, retained for 50 seconds, and then their transformation resistance was detected during cooling. The motor was so controlled in five steps that the added shear distortion speed is constant per unit temperature reduction. The Ni and Cr contents and M {sub S} are in linear relation, and its experimental formula was sought. Even if Ni and Cr contents differ, similar stress relaxing characteristics were presented as long as the M {sub S} points are identical. Therefore, hardness and corrosion resistance can be controlled in welding metals by means of so varying Ni and Cr contents that the M {sub S} point is maintained in a certain range. The transformation resistance showed the minimum value lower by 70 to 80 {degree} C than the M {sub S} point. To apply the phenomena of transformation superplasticity, the temperature difference between preheating paths is important in addition to chemical constituents. 18 refs., 8 figs., 1 tab.

  17. High Frequency Dielectric Characteristics of Electrochromic, WO3 and NiO Films with LiNbO3 Electrolyte

    Science.gov (United States)

    Bulja, S.; Kopf, R.; Tate, A.; Hu, T.

    2016-01-01

    A great deal of attention has been recently focused on Electrochromic (EC) materials and EC based devices, promoting mainly applications related to display technology. In this case, EC based displays are usually actuated by the application of low dc bias voltages, changing their appearance from transparent to opaque. A variety of studies related to the optical characteristics of EC materials have been reported, however, no serious studies so far have been reported on the possible high frequency tunability of the dielectric characteristics of these materials, with the exception of the work by Rose, which presented the operation of a microwave shutter based on conductive polymers operating in the X-band. Here we report tuneable high frequency dielectric characteristics of an Electrochromic (EC) cell with a complimentary structure of Conductor/WO3/LiNbO3/NiO/Conductor in the frequency range from 1 GHz to 20 GHz. The EC cell was prepared using standard semiconductor processing technology, such as lithography, etch and deposition techniques. Our measured results indicate that tunability of high frequency dielectric characteristics as a function of dc bias voltage is achieved, and that a possibility exists for this tunability to be tailored. PMID:27357480

  18. Effect of transformation on stress releasement of stress concentration area in welding. Part 6. ; Stress releasement by transformation superplasticity. Sohentai ga oryoku shuchubu no oryoku kanwa tokusei ni oyobosu eikyo. 6. ; Hentai chososei ni yoru oryoku kanwa

    Energy Technology Data Exchange (ETDEWEB)

    Murata, H. (Yokogawa Medical System Ltd., Tokyo (Japan)); Kato, N.; Iiyama, T. (Tokyo Inst. of Technology, Tokyo (Japan)); Tamura, H. (Nihon Univ., Tokyo (Japan))

    1993-11-05

    As the various contrivances are being done for raising the strength and reliability of the joints in the usual welding execution, the welding defects out of them are thought that they impair the reliability of the joints, and therefore the efforts not so as to let them occur, and in addition, to secure the safety by screening them through the nondestructive inspection, are being performed. In this report, through the double end constraint thermal cycle tests by using the smooth and notched round bar specimen prepared by the friction pressure welding of 9%Ni steel, which could transform at a low temperature, with SUS 304, and moreover through welding by using the welding rod prepared experimentally of the Fe-Ni-Cr system, which could transform at a low temperature, and furthermore through measuring the thermal contraction stress when the extreme strains have been concentrated in the weld metal parts on the way of cooling off, the fracture character of the weld metal has been investigated. In case of actual welding, even when the extreme stress concentration has been created so excessively as D4316 has started to be fractured on its way of cooling off, no crack has occurred in the welding rod of the low temperature transformation. This is thought because of that the superplasticity phenomena due to the martensite transfomation act effectively on the stress releasement. 12 refs., 14 figs., 2 tabs.

  19. Electronic, magnetic and spectroscopic properties of doped Mn(1-x) A x WO4 (A  =  Co, Cu, Ni and Fe) multiferroic: an experimental and DFT study

    Science.gov (United States)

    Mal, Priyanath; Bera, G.; Rambabu, P.; Turpu, G. R.; Chakraborty, Brahmananda; Ramaniah, Lavanya M.; Singh, R. P.; Sen, Pintu; Das, Pradip

    2017-02-01

    The influence of dopants (Co, Cu, Fe and Ni) on the optical, electronic and magnetic properties of multiferroic MnWO4 was studied using Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), magnetization measurements and density functional theory (DFT) calculations. The evolution of Raman spectra with different elemental substitutions at the Mn site was also studied, where the peak width increased with doping of higher mass elements (Co, Cu, Fe and Ni). UV-Vis diffuse reflectance spectroscopy on polycrystalline Mn(1-x) A x WO4 (A  =  Co, Cu, Fe and Ni) (0  ⩽  x   ⩽  0. was performed. The evaluated electronic band gap decreasing with successive Co, Cu and Fe doping reflected the lower ionic radius of the substituted element, and for Ni-doped MnWO4 the band gap increased slightly compared to the parent MnWO4. Bader charge transfer and a partial density of states (PDOS) analysis from DFT simulations predict the appearance of impurity states in the band gap region (of pure MnWO4) from the d orbital of the dopant (Co, Cu and Fe) hybridized with the p orbital of the bonded O atoms due to charge transfer from O to the dopant, and reduced the band gap of Co, Cu and Fe-doped MnWO4. On the other hand, for Ni-doped MnWO4 strong W-O hybridization occurring due to large charge transfer from oxygen to tungsten leads to an increase in the band gap. The band gap, computed using the GGA  +  U method, is close to the experimental value. The signature of the d-d transition observed in the UV spectra is explained in terms of the crystal field stabilization energy caused by the octahedral distortion present in the lattice. Three different antiferromagnetic phases (AF1, AF2 and AF3) are identified in MnWO4 and also for the Co (18.75%)-doped sample. For Cu-doped samples, suppression of the AF1 phase and stabilization of the AF2 phase is observed up to 2 K. Successive doping of Cu leads to the diminution of magnetic frustration. A new

  20. Scalable one-step assembly of an inexpensive photoelectrode for water oxidation by deposition of a Ti- and Ni-containing molecular precursor on nanostructured WO3.

    Science.gov (United States)

    Lai, Yi-Hsuan; King, Timothy C; Wright, Dominic S; Reisner, Erwin

    2013-09-23

    Photoactive in one step! A nanocomposite water-oxidation photocatalyst was assembled by a straightforward and one-step spin-coating procedure of a Ti- and Ni-containing molecule on nanostructured WO3. The photoanode oxidizes water to O2 with good activity and stability in alkaline solution, and thereby features light absorption, charge separation and water-oxidation catalysis (see scheme). © 2013 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  1. Effect of transformation on residual stress in welding. Part 5. ; Stress releasement by transformation superplasticity. Sohentai ga yosetsu zanryu oryoku ni oyobosu eikyo. 5. ; Hentai chososei ni yoru oryoku kanwa

    Energy Technology Data Exchange (ETDEWEB)

    Murata, H. (Yokogawa Medical System Ltd., Tokyo (Japan)); Kato, N. (Tokyo Inst. of Technology, Tokyo (Japan)); Tamura, H. (Nihon Univ., Tokyo (Japan))

    1993-11-05

    The residual stress and angular deformation occurred in welding are the important factors for the welding design. In the previous report, by measuring the welding angular deformation caused by the welding rod prepared experimentally with the various transformation temperatures, it was shown that the materials, which could transform at a low temperature, have been effective to restrain the welding deformation. In addition, also the elongation and stress variation in transformation after welding have been examined in detail, and consequently it has been shown quantitatively, that not only the transformation expansion, but also the transformation superplasticity have acted effectively for the stress relaxation during transformation depending on the condition. In this report, the same as in the previous report, the welding with the multilayers and multi-passes has been performed by using the welding rod prepared experimentally and of Fe-Ni-Cr system, which could transform at a low temperature and had a high stress releasement effect, and then the effect of phase transformation on the welding residual stress has been investigated. As a result, the phase transformation had a tight relation with the welding residual stress, and furthermore the compression stress has been observed on the welding metal depending on the transformation temperature. In addition, it was found that in the welding metal, the compression stress has occurred, the tensile stress has remained directly under it, and it has been connected with a peak part of the tension, and has been redistributed. 18 refs., 8 figs., 1 tab.

  2. Impact of transmission open access on power system operation and planning. In reference to U.S. deregulatory case; Soden access ga denryoku keikaku / un`yo ni ataeru eikyo to kadai. Beikoku kisei kanwa jirei wo sanko to shite

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, Y. [The Institute of Energy Economics, Tokyo (Japan)

    1997-05-01

    The U.S. Federal Energy Regulatory Commission (FERC), in its Orders Nos. 888 and 889 published in 1996, ruled a nondiscriminatory open access to transmission lines, which is mandatory at wholesale level, together with sets of regulations concerned therewith. To explain it more specifically, the open access policy obligates all the utilities operators possessing, controlling and operating transmission lines to provide their power sale and buy activities and transmission services to third parties indiscriminately. This obligation is intended to reduce power charges, increase supply reliability, and provide open and fair power transmission service. This signifies that change in social structures is progressing, in which systems will formed under repetition of competition and cooperation rather than priority to the cooperation in a fixed form in all the economic activities, not only in the electric utilities industry. This paper introduces the contents of the FERC`s transmission open access, power supply situation in California, problems connected thereto, and conception of power transmission congestion control. 24 refs., 11 figs., 3 tabs.

  3. Influence on driver fatigue of vertical vibrations over long distances. Assessment in terms of stress hormones; Driver no unten hiro ni okeru joge shindo no eikyo. Stress hormone wo shiyo to shite

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, T.; Inagaki, H. [Toyota Central Research and Development Labs., Inc., Aichi (Japan)

    1998-05-01

    Driving tests are conducted to obtain some indexes that describe the cumulative effect of the sense of tiredness. The heart rate, Mayer wave related sinus arrhythmia, respiratory sinus arrhythmia, urinary adrenaline, noradrenaline, and cortisol in saliva are tested. Adrenaline and Mayer wave related sinus arrhythmia are ultimately named in view of their correlation with tiredness. It is believed that tiredness is attributable to two factors, which are increase in mental stress and decrease in vigilance. An excitation test is then conducted using a motion simulator. Upon application of 4Hz vibrations (equivalent to the chest section resonance frequency), adrenaline increases sharply, and then decreases sharply upon termination of excitation. Upon application of 1.6Hz vibrations (equivalent to the head section resonance frequency), adrenaline increases but not sharply, and the elevated level is sustained for some time after excitation. Driving tests are next conducted using a vehicle with its suspension fixed and another with 1-2Hz vibrations reduced. Rise in the adrenaline level is found inhibited aboard the latter. No difference is detected in terms of Mayer wave related sinus arrhythmia between the two vehicles. 4 refs., 7 figs., 4 tabs.

  4. 「~に~をV」与「~を~でV」句式论元结构交替分析%An Exploration of the Argument Structure Alternations between [ - ni - wo V] and [ - wo - de V ] Forms

    Institute of Scientific and Technical Information of China (English)

    金镜玉

    2012-01-01

    本文从构式语法的角度,分析研究「~に~をV」与「~を~でV」的论元结构交替现象,探讨其成立的句法条件、规则以及两种句式的关系。研究发现这两种句式的论元结构交替遵循"「ニ/ヲ」与「ヲ/デ」交替"和"「ニ/デ」交替"规则,追根溯源是位移变化和状态变化相互影响的结果。这两种句式具有截然不同的句法意义,从认知角度分析,是主体对事件结构不同焦点的不同认知结果。这也从另一方面解释了形式与意义为统一体,不同形式对应不同意义的普遍语法现象。%The aim of this paper is to analyze "- ni-wo V" and "-wo-de V" forms on the alternative patterns of argument structure from the perspective of construction grammar, exploring their syntactic conditions and principles, as well as the relationship of the two forms. Studies have found that these two forms followed the "ニ/ヲ」与「ヲ/デ" alternating" and "ニ/デ" alternating" rule. They are the result of interactions between the changes of location and state and each of them has different syntactic significance, but from a cognitive point of view, they are different understandings of different event structures. The paper also explains the universal grammatical phenomena wherein the form and meaning is an entity and different forms corresponded to different meanings.

  5. Influences of species of metals and supports on the hydrogenation activity of carbon-supported metal sulfides catalysts; Tanso biryushi tanji shokubai no suisoka kassei ni taisuru kassei kinzoku oyobi tantaishu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sakanishi, K.; Hasuo, H.; Taniguchi, H.; Nagamatsu, T.; Mochida, I. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    1996-10-28

    In order to design catalysts suitable for primary liquefaction stage and secondary upgrading stage respectively in the multi-stage liquefaction process, various carbon-supported catalysts were prepared. Catalytic activities of them were investigated for the hydrogenation of 1-methylnaphthalene, to discuss the influences of metals and carbon species on the catalytic activity. Various water soluble and oil soluble Mo and Ni salts were used for NiMo supported catalysts. Among various carbon supports, Ketjen Black (KB) was effective for preparing the catalyst showing the most excellent hydrogenation activity. The KB and Black Pearl 2000 (BP2000) showing high hydrogenation activity were fine particles having high specific surface area more than 1000 m{sup 2}/g and primary particle diameter around 30 nm. This was inferred to contribute to the high dispersion support of active metals. Since such fine particles of carbon exhibited hydrophobic surface, they were suitable for preparing catalysts from the methanol-soluble metals. Although Ni and Mo added iron-based catalysts provided lower aromatic hydrogenation activity, they exhibited liquefaction activity competing with the NiMo/KB catalyst. 3 refs., 1 fig., 3 tabs.

  6. Effect of C, Si and P on intergranular corrosion susceptibility of type 316 stainless steel; 316 kei stainless ko no ryuiaki fushokusei ni oyobosu kochu C, Si oyobi P no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, M.; Abe, S. [Nippon Steel Corp., Tokyo (Japan)

    1995-07-15

    The effect of C, Si and P on intergranular corrosion (IGC) susceptibility of Type 316 painless steels (SS) has been studied in terms of the composition dependent IGC and the impound dependent IGC. The results obtained are as follows; (1) C increases the IGC existence of Type 316 SS in Huey and Coriou tests by suppressing the precipitation of Laves phase. However, severe IGC occurs in HNO3 + HF and Huey tests when the Cr depleted one is continuously formed at grainboundaries (GB). (2) Si raises the IGC susceptibility both in Huey and Coriou tests. It is considered that Si enhances the precipitation of Laves phase at GB. (3) p also increases the IGC susceptibility both in Huey and Coriou tests by decapitating as Ni-P phosphides at GB. 10 refs., 12 figs., 2 tabs.

  7. Onset of asthma-like symptoms by intratracheal injection of diesel exhaust particles (DEP) to Mice: Role of active oxygen species. Diesel haiki biryushi (DEP) no mausu eno kikannai toyo ni yoru zensoku yobyotai no hatsugen ni tsuite (Tokuni, kassei sansosansei wo kaishita eikyo wo chushin toshite)

    Energy Technology Data Exchange (ETDEWEB)

    Sagai, M.; Ichinose, T.; Furuyama, A. (National Institute for Environmental Studies, Tsukuba (Japan))

    1993-07-10

    In order to examine the poisonous effect of the DEP, the extracts of DEP were injected at various concentration into tracheas of mice. As a result, LD[sub 50] was 0.6 mg (as DEP) and by 0.9 mg all rats were died within 24 hours. All causes of their death were the lung edema. Under the condition of the above examination, when PEG-SOD (polyethylene glycol conjugated superoxide dismutase) was injected to the mice previously one hour before the injection of the extracts of DEP, remarkable decrease of mortality was found. From this change, it was considered that the superoxide O2[sup -] sprang up from the DEP and caused the vascular endothelial damage. In the second stage, the DEP were applied at the lower concentration 10 times at intervals of a week, and the tissues of lungs were observed morphologically. The edema at the bronchial submucosal layer and the circumference of blood vein and the infiltration at the neutrophils and eosinophils were observed. These findings suggest that the substance of poison of the DEP is active oxygen and, by the fact, the increase of vascular permeability and mucous hypersecretion are brought. 43 refs., 8 figs., 1 tab.

  8. Effects of silicon content and austempering condition on the impact characteristics of austempered ductile cast iron. Kyojin kyujo kokuen chutetsu no jinsei ni oyobosu osutenpa shori joken to Si ryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Aoyama, M. (Daido Inst. of Technology, Nagoya (Japan)); Kobayashi, T. (Toyohashi Univ. of Technology, Aichi (Japan)); Matsuo, K. (Kurimoto Iron Works, Ltd., Osaka (Japan))

    1990-07-25

    Austempered spherical graphite cast iron (ADI) is extensively expeted as a mechanical structural material because of high tenacity and resilience as well as fatigue strength and wear resistance. These excellent properties are attributed to the abundantly remaining austenite because the formation of carbides is restricted by the action of the silicon element. It is, therefore, important for obtaining the strong cast iron material to control the amount of the retained austenite. In this study, the impact characteristics was investigated for acquiring the basic materials concerning the influence of the temperature, time of austempering and the amount of silicon. The added amount of silicon is most suitably 2.1%. Samples without Mn and Ni showed an impact value of about 2 times of the amount added. At 400 {degree} C, however, the impact value reduced to half by the growth of coarse ferrite and bentonite. Time of austempering was 1 hour and showed a stable impact value and load of breaking. Transition temperature shifted tolow side by the increase of amount of silicon. 14 refs., 10 figs., 1 tab.

  9. Large-area flexible monolithic ITO/WO3/Nb2O5/NiVOχ/ITO electrochromic devices prepared by using magnetron sputter deposition

    Science.gov (United States)

    Tang, Chien-Jen; Ye, Jia-Ming; Yang, Yueh-Ting; He, Ju-Liang

    2016-05-01

    Electrochromic devices (ECDs) have been applied in smart windows to control the transmission of sunlight in green buildings, saving up to 40-50% electricity consumption and ultimately reducing carbon dioxide emissions. However, the high manufacturing costs and difficulty of transportation of conventional massive large area ECDs has limited widespread applications. A unique design replacing the glass substrate commonly used in the ECD windows with inexpensive, light-weight and flexible polymeric substrate materials would accelerate EC adoption allowing them to be supplemented for regular windows without altering window construction. In this study, an ITO/WO3/Nb2O5/NiVOχ/ITO all-solid-state monolithic ECD with an effective area of 24 cm × 18 cm is successfully integrated on a PET substrate by using magnetron sputter deposition. The electrochromic performance and bending durability of the resultant material are also investigated. The experimental results indicate that the ultimate response times for the prepared ECD is 6 s for coloring at an applied voltage of -3 V and 5 s for bleaching at an applied voltage of +3 V, respectively. The optical transmittances for the bleached and colored state at a wavelength of 633 nm are 53% and 11%, respectively. The prepared ECD can sustain over 8000 repeated coloring and bleaching cycles, as well as tolerate a bending radius of curvature of 7.5 cm.

  10. Effect of reversion treatment on strength and ductility of low C, Cr-Ni martensitic stainless steel with high resistance to weld softening. Yosetsu nanka teiko no takai teitanso Cr-Ni maruten saito kei stainless ko no kyodo, ensei ni oyobosu gyaku hentai shori no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Igawa, T.; Takemoto, T.; Uematsu, Y. (Nisshin Steel Co. Ltd., Tokyo (Japan). Steel R and D Lab.); Hoshino, K. (Nisshin Steel Co. Ltd., Tokyo (Japan))

    1993-08-01

    Like the stainless steel and the stainless steel belt used in the rolling stock, materials treated by process and weld has a high strength and a good ductility, moreover, was expected that weld softening would not occurred. In this study, formation of the ultra-fine crystal grains based on the M to [gamma] reversion transformation of low C, Cr-Ni martensitic stainless steel and effect of Si on change of mechanical properties were investigated. A high-strength stainless steel with a good ductility and without weld softening was developed. Main results obtained are as follows: After a steel was cold-rolled, the reversion treatment at the region between As and Af temperatures (600 to 640[degree]C) was carried out, a duplex structure with diameter of the ultra-fine grains of about 0.5 micron meter that is composed of [gamma] phase concentrated Ni and sintered M phase was formatted, and excellent mechanical properties with a high strength and a good ductility could be obtained, diameter of reversion [gamma] grains was dependent on reversion temperature. Diameter of [gamma] grains became large, and more homogeneous and uniform at higher reversion temperature. 20 refs., 11 figs., 2 tabs.

  11. Substrate patterning with NiOx nanoparticles and hot-wire chemical vapour deposition of WO3x and carbon nanostructures

    Science.gov (United States)

    Houweling, Z. S.

    2011-10-01

    The first part of the thesis treats the formation of nickel catalyst nanoparticles. First, a patterning technique using colloids is employed to create ordered distributions of monodisperse nanoparticles. Second, nickel films are thermally dewetted, which produces mobile species that self-arrange in non-ordered distributions of polydisperse particles. Third, the mobility of the nickel species is successfully reduced by the addition of air during the dewetting and the use of a special anchoring layer. Thus, non-ordered distributions of self-arranged monodisperse nickel oxide nanoparticles (82±10 nm x 16±2 nm) are made. Studies on nickel thickness, dewetting time and dewetting temperature are conducted. With these particle templates, graphitic carbon nanotubes are synthesised using catalytic hot-wire chemical vapour deposition (HWCVD), demonstrating the high-temperature processability of the nanoparticles. The second part of this thesis treats the non-catalytic HWCVD of tungsten oxides (WO3-x). Resistively heated tungsten filaments exposed to an air flow at subatmospheric pressures, produce tungsten oxide vapour species, which are collected on substrates and are subsequently characterised. First, a complete study on the process conditions is conducted, whereby the effects of filament radiation, filament temperature, process gas pressure and substrate temperature, are investigated. The thus controlled growth of nanogranular smooth amorphous and crystalline WO3-x thin films is presented for the first time. Partially crystalline smooth hydrous WO3-x thin films consisting of 20 nm grains can be deposited at very high rates. The synthesis of ultrafine powders with particle sizes of about 7 nm and very high specific surface areas of 121.7±0.4 m2·g-1 at ultrahigh deposition rates of 36 µm·min-1, is presented. Using substrate heating to 600°C or more, while using air pressures of 3·10-5 mbar to 0.1 mbar, leads to pronounced crystal structures, from nanowires, to

  12. Study of stability of the ceramic Ba{sub 2}NiWO{sub 6} in crude petroleum drew back from state - Brazil oil wells; Microestrutura e propriedades mecanicas da ceramica Ba{sub 2}NiWO{sub 6} apos imersao em petroleo cru retirado de pocos de prtroleo do estado de Sergipe - Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Yadava, Y.P.; Bezerra, L.P.; Diniz, M.J.L.; Ferreira, R.A.S. [Universidade Federal de Pernambuco (DEM/UFPE), Recife, PE (Brazil). Dept. de Engenharia Mecanica], e-mail: yadava@ufpe.br

    2008-07-01

    The necessity of developing technologies which make practical the oil-well exploration is notorious. Knowing that those are hostile places is necessary to find materials which are capable to resist to the inclemency caused by those environments. Pondering that the ceramics show the required characteristics to this purpose the present assignment views the elaboration of complex perovskite ceramic Ba{sub 2}NiWO{sub 6} to produce ceramics components parts of temperature sensors to oil-well. To this purpose we studied the ceramic stability when they are vulnerable to the attack of the crude petroleum drew back from ocean and earth's oil-wells of Sergipe state-Brazil. The ceramics were submersed in the mentioned petroleum during thirty days and then they were analyzed by X-ray diffraction, optics microscopy and microhardness Vickers to verify if changes happened in the structure, microstructure and mechanics proprieties characteristics. These results are showed and discussed in this assignment. (author)

  13. Catalytic surface promotion of highly active La0.85Sr0.15Cr0.8Ni0.2O3-δ anodes for La5.6WO11.4-δ based proton conducting fuel cells

    DEFF Research Database (Denmark)

    Solis, C.; Balaguer, M.; Bozza, Francesco

    2014-01-01

    La0.85Sr0.15CrO3-delta (LSC), La0.85Sr0.15Cr0.8Ni0.2O3-delta (LSCN) and LSCN infiltrated with Ni nanoparticles were tested as anodes for symmetrical cells based on La5.6WO11.4-delta (LWO) protonic electrolyte. These chromite-based electrode materials are compatible with LWO material, in contrast...

  14. Effect of massive transformation on formation of acicular structure in austenitic stainless steel weld metal solidified as ferritic single phase. Report 5. Study on solidification and subsequent transformation of Cr-Ni stainless steel weld metals; Feraito tanso de gyokosuru osutenaito kei sutenresu ko yosetsu kinzoku ni okeru ashikyura jo soshiki no keisei ni oyobosu masshibu hentai no eikyo.5. Cr-Ni kei sutenresu ko yosetsu kinzoku no gyoko/hentai ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, H.; Koseki, T.; Okita, S.; Fuji, M. [Nippon Steel Corp., Tokyo (Japan)

    1997-05-05

    The authors clarified that massive transformation occurs at two phase region under To temperature and there is K-S relation between the massive formation phase and base phase using {gamma} stainless steel that solidifies at F mode and forms acicular structure at room temperature structure. There is a possibility of massive transformation in weld metals because the cooling rate below the high temperature To was high even for normal welding process. Thereupon, in this report, whether the massive transformation effects the formation of acicular structure or not was studied as for {gamma} stainless steel weld metal that solidifies at F mode and room temperature structure becomes acicular form of two {delta} and {gamma} phase. As a result, it was clarified that massive transformation occurs at two phase region with temperature below To, and the room temperature structure was acicular form structure irrespective to massive transformation in case of composition with small Cr/Ni ratio even in case of stainless steel that solidifies at F mode. 20 refs., 15 figs., 1 tab.

  15. Joining between alumina and metal by use of plasma sprayed Ni-Al coating on alumina. Alumina ni plasma yoshashita Ni-Al kinzoku himaku wo kaishite no alumina kinzoku tono setsugo

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, N.; Kishitake, K.; Hasebe, M.; Kobayashi, T.; Murashige, K. (Kyushu Institute of Technology, Kitakyushu (Japan). Faculty of Engineering)

    1993-06-30

    A ceramic material is joined and compounded with a metal by spraying another metal on the ceramic material, and then joined with the intended metal because of small adhesion strength in both materials. Adhesion strength of the spraying metal is important even in this case. The present experiment performed plasma spraying of Ni-Al mixed powder on alumina to investigate effects of the heating on the adhesion strength. Solder joining of Ni-Al sprayed alumina with soft steel rod and copper rod was also tested. As a result, the adhesion strength of as-sprayed Ni-Al film on the alumina was about 5 MPa and maximum of 10 MPa. Heating the materials to 1173 K for 10 hours or longer provided an average strength of 20 MPa and a maximum strength of 35 MPa. Improving the adhesion strength requires spinel to be produced through reactions on the interface. It was found that alumina can be joined with metal easily by going through this film. 12 refs., 6 figs.

  16. Preparation of Ni-Cr overlay weld alloy with finely dispersed NbC particles from (Ni-Cr)/NbC composite powder. Fukugo funmatsu wo mochiita bisai NbC ryushi bunsan Ni-Cr nikumori gokin no sakusei

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, T.; Takatani, Y. (Hyogo Prefectural Inst. of Industrial Research, Hyogo (Japan)); Harada, Y.; Nagai, K. (Tocalo Co. Ltd., Kobe (Japan))

    1992-11-20

    In previous studies, Ni-Cr overlay alloy containing NbC particles, formed by the plasma powder welding process, was found to exhibit excellent wear and corrosion resistances. However, any overlay alloy with dispersed NbC particles having a diameter below a few micron, has not been yet obtained. In this study, a composite powder was prepared by compounding 40 vol.% of NbC powder having an average grain diameter of 1.3 [mu]m into Ni-50 mass% Cr alloy powder, and then mixing, granulating and sintering. Plasma powder weddings were carried out on a mild steel plate using this complex powder, and the effect of plasma arc current on melting of complex powder particles and dispersion behavior of NbC particles was studied by structure observation and X-ray diffractometry. As a result, it was clarified that by selecting the proper plasma arc current and controlling the heat input, uniform dispersion of fine NbC particles having a diameter of a few micron into the matrix was possible. 18 refs., 8 figs., 3 tabs.

  17. Hydrogenation of carbon monoxide over mixed catalysts. Co-Ni/MnO-ZrO sub 2 to zeolite kara naru kongo shokubai wo mochiita issankatanso no suisoka

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, T.; Iwakuni, H.; Eguchi, K.; Arai, H. (Graduate School of Engineering Sciences, Kyushu Univ., Fukuoka (Japan). Department of Materials Science and Technology)

    1990-07-10

    The mechanical mixtures of Co-Ni/MnO-ZrO {sub 2} and zeolite were used as catalysts for the selective synthesis of gasoline by CO hydrogenation. Formation of branched-paraffins was promoted but that of higher hydrocarbons than carbon number of 10 was suppressed by combination with zeolite. The product distribution strongly depended on the type of zeolite catalyst. Pentasil zeolite was active for the formation of branched-paraffins, probably because of the cracking reaction occurring on the strong acid sites. The formation of branched paraffin was further promoted by ion-exchange with Pt. The mixture of Co-Ni/MnO-ZrO {sub 2} and PtH-pentasil zeolite was very active for the formation of gasoline with high octane number. 34 refs., 10 figs., 2 tabs.

  18. Non-contact evaluation of mechanical properties of electroplated wear resistant Ni-P layer from the velocity dispersion of laser SAW; Laser reiki Rayleigh ha no sokudo bunsan wo mochiita taimamo Ni-P mekkiso tokusei no hisesshoku hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, Y.; Cho, H.; Takemoto, M. [Aoyama Gakuin University, Tokyo (Japan). Faculty of Science and Engineering; Nakayama, T. [Kobe Steel Ltd., Kobe (Japan)

    1996-11-01

    We developed a new laser surface acoustic wave (SAW) system and applied this to estimate the mechanical properties of the wear-resistant Ni-P layer electroplated on a stainless steel. The velocity dispersions of Rayleigh wave of the as -plated and heat-treated Ni-P layer were obtained by the one point time domain signal processing. The Ni-P layers with excellent wear resistance produced by the heated treatment higher than 725K were found to show higher Rayleigh velocities than that of the substrate steel, while the Ni-P layer with poor wear resistance showed lower velocities. Young`s moduli of the Ni-P layer, estimated so as the computed velocity dispersion agreed with the measured one, increased with the increase of wear resistance. 10 refs., 9 figs., 2 tabs.

  19. Effects of Fibers on Properties of Bitumens; Senitenkazai ga asufuaruto no seijo ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Hiroshi.; Moriyoshi, Akihiro. [Hokkaido University, Hokkaido (Japan). Faculty of Engineering; Takahashi, Shigeki.; Cabrera, J.G. [University of Leeds, Leeds (United Kingdom). Civil Engineering Materials Unit

    1999-07-01

    High-viscosity bitumen blended with Styrene Butadiene Copolymer (SBS) and fibers is used, of late, for drainage pavement, for the purpose to prevent cracking and rutting, as well as to prevent flow carrying bituminous mixtures. However, it was not impossible to evaluate whether, or not, the mechanical properties and durability of such bitumens are suitable, at extremes of low or high temperatures. The authors, therefore, have developed a method for determining the mechanical properties of these bitumens, using some new testes, such as the Improved Fraass Breaking Point (IFBP) Test, the Moriyoshi Breaking Point (MBP) Test, the High-Temperature Long-Time Durability (HTLTD) Test and the Bending Test. The method employed for measuring viscosity at high temperature was the Flow Test by rheometer. This paper describes the various results of tests for high-viscosity bitumens blended with the SBS and Fibers. The authors obtained some brittle points and mechanical properties of these bitumens by using the said testers. The authors found the fracture properties and durability of bitumen blend-ed with various fibers unfavorable, compared with the original bitumens. (author)

  20. Effects on water ecosystem by synthetic detergents. Gosei senzai no seitaikei ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, N. (Shiga University, Shiga (Japan))

    1993-05-01

    Considerations have been given on the effects of commercially available detergents on environments and ecosystems. As a result of the water quality test, BOD, COD, TOD, and TOC of powder soaps showed as high value as 6.7 times, 2.9 times, 2.6 times, and 3.1 times those of phosphorus-free powdered synthetic detergents. According to the result of a mortality experiment on water fleas, a concentration of surfactant MBAS in household waste water channels of 50 ppm has caused a 100% death after 24 hours, which is a considerably higher mortality than with soaps. Aggravation of aquatic environment in the Lake Biwa has generated a sudden increase in mud snails, which play a large role in water purification. Soaps contain two to three times more organics than synthetic detergents, but the decomposability of the organics is so high that naturally purifying function does not decline. Fishery products suffer stronger toxicity from synthetic detergents than from soaps. It has been indicated that surfactant LAS with low concentration accelerates ecological condensation of organic chlorine compounds in fishes. Difference in types of commercially available detergents and types of sea urchins has given the varied effects on fertilization rates, first cleavage occurrence rates, normal generation rates, and incubation rates. 21 refs., 3 figs., 3 tabs.

  1. Preparation of biodegradable microcapsules with (W/O/W) emulsion in solvent evaporation; (W/O/W) fukugo emulsion wo mochiita ekichu kansoho ni yoru seibunkaisei microcapsule no chosei

    Energy Technology Data Exchange (ETDEWEB)

    Kiyoyama, S.; Shiomori, K.; Baba, Y.; Kawano, Y. [Miyazaki University, Miyazaki (Japan). Faculty of Engineering; Yoshizawa, H.; Hatate, Y. [Kagoshima University, Kagoshima (Japan). Faculty of Engineering

    1997-03-10

    This paper describes the preparation of biodegradable microcapsules which can control the shape and size of capsules and also can control the discharge of contents. The biodegradable polymers are frequently used as medical materials, and have attracted attention as base materials for drug prescription. At first, (W/O) emulsion was prepared by dispersing an inner aqueous ascorbic acid Mg salt solution into the organic solution consisting of biodegradable poly(3HV-co-3HB) membrane material and 1,2-dichloroethane. Then, (W/O/W) emulsion was prepared by dispersing the (W/O) emulsion into the outer aqueous phase consisting of interfacial active agent and dispersion stabilizer. The biodegradable microcapsules were prepared by the solvent evaporation process including heating, evaporation of solvent by air blasting, and vacuum drying. The stability of solvent evaporation depended on the concentration of membrane material and solvent removal rate. The surface characteristics of microcapsules were not affected by the volume fraction of the inner aqueous phase during the primary emulsion, but by the solvent removal rate and dispersion stabilizer. The surface characteristics could be controlled by the solvent evaporation with considering these factors. 12 refs., 11 figs., 2 tabs.

  2. Modification of the performance of WO{sub 3}-ZrO{sub 2} catalysts by metal addition in hydrocarbon reactions

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Gerardo Carlos; Manuale, Debora Laura; Benitez, Viviana Monica; Vera, Carlos Roman; Yori, Juan Carlos, E-mail: jyori@fiq.unl.edu.ar [Instituto de Investigaciones en Catalisis y Petroquimica, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Consejo Nacional de Investigaciones Cientifica y Tecnicas, Santiago del Estero Santa Fe (Argentina)

    2012-07-01

    A study of the different hydrocarbon reactions over Ni doped WO{sub 3}-ZrO{sub 2} catalysts was performed. Ni was found as NiO at low Ni concentration while at high Ni concentrations a small fraction was present as a metal. For both cases, Ni strongly modified total acidity and concentration of strong acid sites. In the cyclohexane dehydrogenation reaction, Ni addition promotes both benzene and methyl cyclopentane production. The hydroconversion activity (n-butane and n-octane) increases with the augment of total acidity produced by Ni. The selectivity to reaction products is modified according to the acid strength distribution changes produced by Ni addition. (author)

  3. Improved visible light photocatalytic activity of WO3 through CuWO4 for phenol degradation

    Science.gov (United States)

    Chen, Haihang; Xiong, Xianqiang; Hao, Linlin; Zhang, Xiao; Xu, Yiming

    2016-12-01

    Development of a visible light photocatalyst is challenging. Herein, we report a significant activity enhancement of WO3 upon addition of CuWO4. Reaction was carried out under visible light for phenol degradation in aqueous suspension in the presence of H2O2. A maximum reaction rate was observed at 1.0 wt% CuWO4, which was 2.1 and 4.3 times those measured with WO3 and CuWO4, respectively. Similar results were also obtained from the photocatalytic formation of OH radicals, and from the electrochemical reduction of O2. A possible mechanism responsible for the improved activity of WO3 is proposed, involving the electron transfer from CuWO4 to WO3, followed by the reduction of H2O2 over WO3.

  4. Improved Charge Separation in WO3/CuWO4 Composite Photoanodes for Photoelectrochemical Water Oxidation

    Directory of Open Access Journals (Sweden)

    Danping Wang

    2016-05-01

    Full Text Available Porous tungsten oxide/copper tungstate (WO3/CuWO4 composite thin films were fabricated via a facile in situ conversion method, with a polymer templating strategy. Copper nitrate (Cu(NO32 solution with the copolymer surfactant Pluronic®F-127 (Sigma-Aldrich, St. Louis, MO, USA, generic name, poloxamer 407 was loaded onto WO3 substrates by programmed dip coating, followed by heat treatment in air at 550 °C. The Cu2+ reacted with the WO3 substrate to form the CuWO4 compound. The composite WO3/CuWO4 thin films demonstrated improved photoelectrochemical (PEC performance over WO3 and CuWO4 single phase photoanodes. The factors of light absorption and charge separation efficiency of the composite and two single phase films were investigated to understand the reasons for the PEC enhancement of WO3/CuWO4 composite thin films. The photocurrent was generated from water splitting as confirmed by hydrogen and oxygen gas evolution, and Faradic efficiency was calculated based on the amount of H2 produced. This work provides a low-cost and controllable method to prepare WO3-metal tungstate composite thin films, and also helps to deepen the understanding of charge transfer in WO3/CuWO4 heterojunction.

  5. Development of hydriding alloys with multi-functionally-graded properties and their applications to energy conversion devices; Keishagata fukugo kino wo hyomen ni motsu suiso kyuzo gokin no kaihatsu to energy henkan gijutsu eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Suda, S.; Kadoma, H.; Nagamoto, H.; Okura, T. [Kogakuin University, Tokyo (Japan)

    1997-02-01

    This paper describes the formation of fluoride layer on the surface of hydriding alloys. The fluoride formation reaction consists of a reduction removal process of surface oxide and a fluorination process. Specific surface area of alloy grains can be increased by the hydrogenation reaction in the surface layer accompanied with the removal of surface oxide, which results in easier permeation of molecular hydrogen into fluoride layer. During the fluorination process, a large amount of Ni in the alloy components is eluted, which results in the reduction of Ni distribution immediately under the fluoride layer in the alloy. Consequently, collector sites near the surface are reduced, and conductivity among alloy grains is degraded. To enhance the hydrogen collector sites, specific surface area of alloy grains can be increased by controlling the pH value of fluorination treatment solution in a given range. Moreover, performance of fluoride layer can be advanced by electrochemically dispersing metal Ni in the fluoride layer using Ni complex ion mixed in the treatment solution. 2 refs., 3 figs.

  6. BTX production by in-situ contact reforming of low-temperature tar from coal with zeolite-derived catalysts; Zeolite kei shokubai wo mochiita sekitan teion tar no sesshoku kaishitsu ni yoru BTX no seisei

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, T.; Fuda, K.; Murakami, K.; Kyo, M.; Hosoya, S.; Kobayashi, S. [Akita University, Akita (Japan). Mining College

    1996-10-28

    On BTX production process from low-temperature tar obtained by pyrolysis of coal, the effect of exchanged metallic species and reaction temperature were studied using metallic ion-exchanged Y-zeolite as catalyst. In experiment, three kinds of coals with different produced tar structures such as Taiheiyo and PSOC-830 sub-bituminous coals and Loy Yang brown coal were used. Y-zeolite ion-exchanged with metal chloride aqueous solution was used as catalyst. Zn{sup 2+}, Ni{sup 2+} and In{sup 3+} were used as metal ions to be exchanged. The experiment was conducted by heating a pyrolysis section up to 600{degree}C for one hour after preheating a contact reforming section up to a certain proper temperature. As a result, the Ni system catalyst was effective for BTX production from aromatic-abundant tar, while the Zn system one from lower aromatic tar. In general, relatively high yields of toluene and xylene were obtained at lower temperature, while those of benzene at higher temperature. 4 figs., 1 tab.

  7. Characterization of Porous WO3 Electrochromic Device by Electrochemical Impedance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Chien Chon Chen

    2013-01-01

    Full Text Available This paper concerns the microstructure of the anodic tungsten oxide (WO3 and its use in an electrochromic (EC glass device. When voltages between 100 V and 160 V were applied to tungsten film for 1 h under 0.4 wt. % NaF electrolyte, porous WO3 film was formed. The film, which had a large surface area, was used as electrochromic film for EC glass. The average transmittance in a visible region of the spectrum for a 144 cm2 EC device was above 75% in the bleached state and below 40% in the colored state, respectively. Repeatability using of the colored/bleached cycles was tested good by a cyclic voltammograms method. The internal impedance values under colored and bleached states were detected and simulated using an electrical impedance spectra (EIS technique. The EC glass impedance characteristics were simulated using resistors, capacitors, and Warburg impedance. The ITO/WO3, WO3/electrolyte, electrolyte/NiO, and NiO/ITO interfaces can be simulated using a resistance capacitance (RC parallel circuits, and bulk materials such as the indium tin oxide (ITO and conducting wire can be simulated by using a series of resisters.

  8. Study of selective oxidation of methane catalyzed by solid superacid in unique reaction field; Tokushu hannoba no kotai chokyosan wo mochiiru methane no sentaku sanka hanno ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Misonoo, M.; Tatsumi, T.; Mizuno, T.; Inumaru, T. [The University of Tokyo, Tokyo (Japan)

    1997-02-01

    Selective oxidation of lower alkanes by use of heteropolymeric compounds is studied. Alkanes are activated on Cs2.5H0.5PW12O40 serving as catalyst, and their activity and selectivity improve when the catalyst is developed into a dual function catalyst in which Cs and Pt are combined. A success is reported of the synthesis of a heteropolymeric acid in which two molecules of the coordination element wolfram are replaced with a transition metal of the first period, on which acid the oxidation of cyclohexane is enhanced. Cs2.5Ni0.08H1.34PVMo11O40 as a metal/heteropolymeric acid dual function catalyst enables the direct oxidation (9% recovered at 340{degree}C) of isobutane into a methacrylic acid, which is attributed to the harmonious coordination of the oxidizing work of the catalyst and acidity. It is possible to oxidize propane into the acrylic acid, but not ethane into the acetic acid. In the case of Pd/Cs2.5H1.5PVMo11O40, the formic acid, methanol, etc., are produced upon addition of hydrogen to the system. This reaction in the hydrogen/oxygen system is supposed to take place via activated oxygen seeds as in the case of oxidation by hydrogen peroxide. 10 refs.

  9. Goal of ISO14001(Environmental management systems). Centering around environmental impact assessment; ISO14001 ( kankyo management system ) no mezashiteirumono. Kankyo eikyo hyoka wo chushin to shite

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, T. [Japan Audit and Certification Organization for Environment, Tokyo (Japan)

    1998-11-20

    ISO14001 (Environmental management systems) came into effect internationally on September 1, 1997. The objective is continued improvement of environment to harmonize with continuous development of economy, expecting enterprises to tackle the system voluntarily. The point of ISO14001 and environmental impact assessment, which is the most difficult subject to understand, are described. ISO14001 becomes the subject of inspection and authentication, and sufficient study and preparation are required for the part of enterprises. Enterprises are required to clearly publicize the system as a top management system. `Environmental aspects` and `environmental impact` are analyzed and evaluated, and the process of connecting with the `environment objectives` and `environmental targets` is explained. To grasp environmental aspects, activities and processes by the operation of the enterprise itself must be extracted for the `input` and `output.` The process of `environmental impact assessment` is put in order and shown. 7 figs.

  10. Density Measurements of Na2WO4-WO3-ZnO Melts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on Archimedes principle, the densities of Na2WO4-WO3-ZnO melts at a fixed mole ratio of 3.43 of Na2WO4 to ZnO were measured. The results indicated that there was a linear relationship between the densities and temperatures at a fixed composition. At a fixed temperature, the linear relationship between densities and compositions showed different slop within different composition regions. The reasons were explained in view of ionic composition changes.

  11. Electrochemical Preparation of WO_3 Nanowire Arrays

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results Ordered WO3 nanowires arrays have been fabricated by electrochemical deposition with anodic aluminum oxide (AAO) templates and annealing the W nanowire arrays in air at 400 ℃. The morphology and the chemical composition of WO3 nanowires arrays were characterized by Scanning Electron Microscopy (SEM),Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and X-ray diffraction (XRD). The results show that the diameters of the WO3 nanowires are about 90 nm, which is in go...

  12. Synthesis and characterization of WO3 nanomaterials.

    Science.gov (United States)

    Pandey, N K; Tiwari, Karunesh; Roy, Akash

    2011-02-01

    This work reports a simple, quick and economical method to prepare WO3 nanomaterials. Prepared tungsten trioxide materials have been sintered at 700 degrees C for three hours. The material has been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Crystallite size of the WO3 nanostructures obtained by Shearer's formula are between 12 and 72 nm and their grain size by SEM are from 20 to 105 nm. The humidity-sensitive electrical properties of the WO3 nanomaterial have been studied using d.c. measurements.

  13. Effect of intermittent light on oxygen production of Spirulina platensis; Supirurina no sansohassei ni oyobosu shukiko no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ohira, Y.; Abe, T.; Kuga, Y.; Ando, K. [Muroran Institute of Technology, Hokkaido (Japan). Dept. of Applied Chemistry

    2000-05-10

    S. platensis media were irradiated with intermittent light interrupted by a slit in a rotating disk. The effects of the light periodicity, irradiation time, and dark time during a cycle on the oxygen production rate of S. platensis are experimentally discussed. The following oxygen production ratio was used as the index to compare the oxygen production rate between the intermittent light and the continuous light. (Oxygen production ratio)=(Oxygen volume produced by intermittent light)/(Opening ratio of the disk)(Oxygen volume produced by continuous light). When S. platensis media were irradiated with the intermittent light having a periodicity of 0.0044-0.60 s{sup -1}, the oxygen production ratio increased with an increased with an increase in light periodicity. The value of the oxygen production ratio is greater than one when the irradiation time during a cycle is shorter than 1 s. Under these conditions, the oxygen production ratio increases with increasing dark time. the effect of the intermittent light on the oxygen production rate of S. platensis was found to be qualitatively described by the simple model which combined the oxygen production rate of S. platensis and the respiration rate. (author)

  14. Effect of Initial nitrite concentration on growth of spirulina platensis; Supirurina no zoshoku ni oyobosu ashosan ion shonodo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ohira, Y.; Obata, E.; Kuga, Y.; Ando, K. [Muroran Inst. of Tech., Hokkaido (Japan). Dept. of Applied Chemistry; Yamada, S.

    2000-09-10

    The effect of the initial nitrite concentration on the growth of S. platensis was experimentally investigated using the medium added to the sodium nitrite of 0.0-1.6 kg{center_dot}m{sup -3}. When the initial nitrite concentration is smaller than 0.8 kg{center_dot}m{sup -3}, the growth rate is greater than that without nitrite. The specific growth rate had the maximum value and is approximately 1.3 times that of a standard medium when the range of the initial nitrite concentration is 0.3-0.4 kg{center_dot}m{sup -3}. When the initial nitrite concentration is greater than 0.8 kg{center_dot}m{sup -3}, the growth rate was smaller than that of a standard medium due to nitrite inhibition. (author)

  15. Study about the effect of microgravity on biofunctions; Seitai kino eno bisho juryoku no eikyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    A study is made for the elucidation of the effect of microgravity on biofunctions. The protoplast of shiitake is exposed to microgravity and then cultured, and a significant difference occurs. The rate of colony formation by cell fusion in the test sector is found to be two times higher than that in the control sector. When swimming ciliates which are unicellular are suddenly exposed to microgravity, their swimming speeds changed differently according to the direction of swimming. When a mouse subjected to acupuncture for three days is exposed to microgravity, its water metabolism and excretory function are enhanced. A mouse treated with Chinese medicine reacts in the similar way. The change due to microgravity in the amount of acetylcholine in the hypothalamus is found characteristically time dependent. Mice infected with lethal herpes viruses just after exposure to microgravity die at a rate in proportion to the number of exposures and to the amount of viruses given. The migration speed of chemical stripes in case of a gel-base BZ (Belousov-Zhabotinsky) reaction under microgravity is equal to that on the ground. The trigger wave migration speed in case of a water solution-base BZ reaction under microgravity is reduced to approximately 80% of the speed on the ground. 12 refs., 31 figs., 3 tabs.

  16. Evaluation on the effect of tsunami and seaquake on the floating structure; Tsunami kaishin no futai ni taisuru eikyo hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K.; Suzuki, H.; Hosomi, I. [The University of Tokyo, Tokyo (Japan); Nahata, H. [The Long-Term Credit Bank of Japan, Ltd., Tokyo (Japan)

    1996-12-31

    The effects of tsunami and seaquake on large floating structures are theoretically studied, where these effects are followed in terms of local strength using the equation proposed by Sells to predict surface shapes changed by seaquake-caused uplift of the seabottom. The equation is combined with the one for tsunami propagation, to better predict the tsunami motion. The simulation results indicate the necessity of considering the effects of tsunami for the design of a large floating structure. The authors discuss that the effect of tsunami is minimized when a floating structure is set at a depth of at least 40 to 50m, chain length should be determined by equalizing the breaking weight with the load at which the structure starts to move, and a structure should be set at a position where it is not attacked by transverse waves. They also discuss that seaquake intensity should be predicted by the equation of motion of compressible fluid, and, noting local strength of a floating structure, it will not be damaged when it is at least 16mm thick under the conditions of 2m as seabottom uplift and 0.5m as draft depth. 15 refs., 9 figs., 2 tabs.

  17. Effect of ambient gas density for diesel spray; Diesel funmu ni taisuru fun`iki mitsudo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yokohashi, M.; Suzuki, T.; Oshima, R. [Tohokugakuin University, Sendai (Japan); Ono, A. [Shinryo Corp., Tokyo (Japan)

    1997-10-01

    Effect of ambient gas density for fuel spray are measured to investigate the Diesel spray behavior. The change of ambient gas density has been given by pressuring N2 gas and using a high density atmospheric pressure SF6 gas. The measurement are performed for the spray penetration and angle. As a result, the spray penetration is confirmed same tendency at the change of density by pressuring N2 and using SF6. Though spray angle is required modification with viscosity. 2 refs., 11 figs.

  18. Evaluation on the effect of tsunami and seaquake on the floating structure; Tsunami kaishin no futai ni taisuru eikyo hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K.; Suzuki, H.; Hosomi, I. [The University of Tokyo, Tokyo (Japan); Nahata, H. [The Long-Term Credit Bank of Japan, Ltd., Tokyo (Japan)

    1996-12-31

    The effects of tsunami and seaquake on large floating structures are theoretically studied, where these effects are followed in terms of local strength using the equation proposed by Sells to predict surface shapes changed by seaquake-caused uplift of the seabottom. The equation is combined with the one for tsunami propagation, to better predict the tsunami motion. The simulation results indicate the necessity of considering the effects of tsunami for the design of a large floating structure. The authors discuss that the effect of tsunami is minimized when a floating structure is set at a depth of at least 40 to 50m, chain length should be determined by equalizing the breaking weight with the load at which the structure starts to move, and a structure should be set at a position where it is not attacked by transverse waves. They also discuss that seaquake intensity should be predicted by the equation of motion of compressible fluid, and, noting local strength of a floating structure, it will not be damaged when it is at least 16mm thick under the conditions of 2m as seabottom uplift and 0.5m as draft depth. 15 refs., 9 figs., 2 tabs.

  19. Effects of porous throuat on transonic diffuser; Tako shroat ga sen`onsoku diffuser ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yaga, M.; Nagai, M.; Haga, T.; Miyara, T. [Univ. of the Ryukyus, Okinawa (Japan). College of Engineering; Tomita, N. [Hitachi, Ltd., Tokyo (Japan)

    1995-09-30

    The effects of the porous throat on a transonic diffuser were investigated experimentally by wall static pressure measurements and by schlieren optical observations. The porous throat consists of a wall with 126 holes and a cavity underneath it so that the flow around the shock wave can circulate through the porous wall. The results show that no shock wave was observed at 8096 of the porous region from the throat and that the pressure fluctuations in the transonic diffuser were greatly reduced by the porous throat. According to the frequency analysts, the frequency range attenuated by the porous region is between about 700 Hz and 1k Hz and the frequencies lower than 700 Hz have still remained. 9 refs., 8 figs.

  20. Nb2O5 (WO3; MoO3; Fe2O3; NiO – Al ПОСЛЕ МЕХАНИЧЕСКОЙ АКТИВАЦИИ

    Directory of Open Access Journals (Sweden)

    Абузин, Ю.А.

    2016-07-01

    Full Text Available В статье рассмотрены алюмотермические реакции в порошковых системах Nb2O5 (WO3, MoO3, Fe2O3, NiO – Al после механической активации для получения композиционных материалов на основе твёрдого раствора ниобия с армированием частицами Al2O3. Исследование выявило наличие необходимых и достаточных условий для реализации двойной стехиометрической кислородообменной реакции в режиме испарения части её продуктов. Исследованные реакции параллельно формируют частицы оксида алюминия, ниобиевой матрицы и легирующего элемента, образующего с ниобием твердый раствор, образуя композиционные порошки с объёмной долей армирующей фазы на уровне 64 – 72%.

  1. The Preparation of CoWO4/WO3 Nanocomposite Powder

    Institute of Scientific and Technical Information of China (English)

    SHAO Gang-qin; GUO Jing-kun; XIE Ji-ren; DUAN Xing-long; WU Bo-lin; YUAN Run-zhang

    2004-01-01

    Ammonium metatungstate and cobalt nitrate were mixed at the molecular level in distilled water and then spray-decomposed to CoWO4/WO3 nanocomposite powder.The particle morphology,crystalline size,forming course,chemical composition and phase structure of the powder were studied by SEM,TEM,DTA-TG,IR and XRD,respectively.Results show that the powder is homogeneous,spherical and nano-aggregated.

  2. Development of a new electroplating process for Ni-W alloy deposits

    DEFF Research Database (Denmark)

    Mizushima, Io; Tang, Peter Torben; Hansen, Hans Nørgaard

    2005-01-01

    In the present work, the effect of the complexing agents citrate, glycine and triethanolamine (TEA) on the electrodeposition of Ni-W layers from electrolytes based on NiSO4 and Na2WO4, is investigated. The investigations include measurement of the current efficiencies, determination of the tungsten...

  3. Development of a new electrolyte for deposition of Ni-W alloys

    DEFF Research Database (Denmark)

    Mizushima, Io; Tang, Peter Torben; Hansen, Hans Nørgaard

    2005-01-01

    In the present work, the effect of the complexing agents citrate, glycine and triethanolamine (TEA) on the electrodeposition of Ni-W layers from electrolytes based on NiSO4 and Na2WO4, is investigated. The investigations include measurement of the current efficiencies, determination of the tungsten...

  4. WO{sub 3} thin film based multiple sensor array for electronic nose application

    Energy Technology Data Exchange (ETDEWEB)

    Ramgir, Niranjan S., E-mail: niranjanpr@yahoo.com, E-mail: deepakcct1991@gmail.com; Goyal, C. P.; Datta, N.; Kaur, M.; Debnath, A. K.; Aswal, D. K.; Gupta, S. K. [Thin Film Devices Section, Technical Physics Division, Bhabha Atomic Research Centre, Mumbai–400085 (India); Goyal, Deepak, E-mail: niranjanpr@yahoo.com, E-mail: deepakcct1991@gmail.com [Thin Film Devices Section, Technical Physics Division, Bhabha Atomic Research Centre, Mumbai–400085 (India); Centre for Converging Technologies, University of Rajasthan, Jaipur-302004 (India)

    2015-06-24

    Multiple sensor array comprising 16 x 2 sensing elements were realized using RF sputtered WO{sub 3} thin films. The sensor films were modified with a thin layer of sensitizers namely Au, Ni, Cu, Al, Pd, Ti, Pt. The resulting sensor array were tested for their response towards different gases namely H{sub 2}S, NH{sub 3}, NO and C{sub 2}H{sub 5}OH. The sensor response values measured from the response curves indicates that the sensor array generates a unique signature pattern (bar chart) for the gases. The sensor response values can be used to get both qualitative and quantitative information about the gas.

  5. Detection and phylogenetic analysis of bacteriophage WO in spiders (Araneae).

    Science.gov (United States)

    Yan, Qian; Qiao, Huping; Gao, Jin; Yun, Yueli; Liu, Fengxiang; Peng, Yu

    2015-11-01

    Phage WO is a bacteriophage found in Wolbachia. Herein, we represent the first phylogenetic study of WOs that infect spiders (Araneae). Seven species of spiders (Araneus alternidens, Nephila clavata, Hylyphantes graminicola, Prosoponoides sinensis, Pholcus crypticolens, Coleosoma octomaculatum, and Nurscia albofasciata) from six families were infected by Wolbachia and WO, followed by comprehensive sequence analysis. Interestingly, WO could be only detected Wolbachia-infected spiders. The relative infection rates of those seven species of spiders were 75, 100, 88.9, 100, 62.5, 72.7, and 100 %, respectively. Our results indicated that both Wolbachia and WO were found in three different body parts of N. clavata, and WO could be passed to the next generation of H. graminicola by vertical transmission. There were three different sequences for WO infected in A. alternidens and two different WO sequences from C. octomaculatum. Only one sequence of WO was found for the other five species of spiders. The discovered sequence of WO ranged from 239 to 311 bp. Phylogenetic tree was generated using maximum likelihood (ML) based on the orf7 gene sequences. According to the phylogenetic tree, WOs in N. clavata and H. graminicola were clustered in the same group. WOs from A. alternidens (WAlt1) and C. octomaculatum (WOct2) were closely related to another clade, whereas WO in P. sinensis was classified as a sole cluster.

  6. Study of impacts of north american free trade agreement over the international labor migration; Hokubei juyuboeki kyotei no kokusai rodoryoku ido ni ataeru eikyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Koido, Akihiro [Sophia University, Tokyo (Japan). Institute of International Relations

    1998-12-16

    This project tried to analyze the effects of transnational economic integration on the immigration flow from developing countries, focusing the case of NAFTA and Mexico. Field interviews with 30 plants of Japanese and U.S. firms with regard to locational and labor market strategy made it possible to analyze concrete effects of investment on labor migration. The rapidly expanding export oriented in-bond industry is incorporating new source of labor by spatially shifting to interior states. On the other hand, new mode of global competition, centered around quality, product diversity, acceleration of product innovation, gave a special advantage to border location and gave rise to industrial agglomeration of specific sectors in specific cities. This industrial dynamics lead not to balance of labor market among regions, but to further labor migration to the north. In future, by utilizing the concept of industrial agglomeration in a more systematic manner, I would like to develop more specific understanding of migration within the context of transnational regional integration. (author)

  7. Numerical simulation for Savonius rotors. Effects of shed vortices on running performance; Savonius fusha ni kansuru suchi keisan. Hoshutsuuzu ga unten tokusei ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ishimatsu, K.; Shinohara, T.; Kage, K.; Okubayashi, T. [Oita University, Oita (Japan). Faculty of Engineering

    1995-01-25

    Considerations have been given on the effects of shed vortices on running performance based on a drawing of the flow fields around a Savonius rotor with semi-circular blades (a drawing depicting the result of calculations using the finite volume method based on two-dimensional incompressible Navier-Stokes equations). A drawing of time-based change in the flow field using a relative velocity vector and an equivalent vorticity line, and a drawing of pressure distribution on the surface of and around the blades were used to indicate that the vortex behavior and the pressure field differ respectively because of increase in the circumferential speed ratio and the existence of blade clearance. The following matters are indicated: the reduction in the torque coefficient in association with increase in the circumferential speed ratio is caused importantly by the separation vortices from the rear face of a leading side blade entering into a concave portion in a return side blade; and the reason for the torque coefficient growing larger above a certain circumferential speed ratio in the case of having blade clearance than the case not having the blade clearance is because the separation vortices from the rear face of the blade become more difficult of entering into the concave portion due to a flow passing through the clearance. 4 refs., 11 figs.

  8. Effects of heat release rate on NOx time history in diesel combustion; Diesel nensho ni okeru netsu hasseiritsu keika ga NOx nodo rireki ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ishiyama, T.; Miwa, K.; Higashida, M. [Tokushima Univ., Tokushima (Japan). Faculty of Engineering; Watanabe, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1996-06-25

    For determining the optimum combination of combustion control techniques to reduce NOx emission from diesel engines, it is important to clarify the effects of each technique not only on the NOx emission but also on its time history during combustion. In this paper, NOx concentration in the combustion chamber of a rapid compression machine has been measured by using a total gas sampling method. In order to elucidate the relation between NOx history and heat release rate, air temperatures nozzle hole size and air motion are varied to control the heat release process. The results show that NOx emission is not solely dependent upon initial combustion. Air utilization in the main diffusive combustion phase has great influence on NOx formation and its decay. NOx formation is accelerated by activation of the initial stage of the main combustion when using a nozzle with small holes. 9 refs., 13 figs.

  9. Effect of static magnetic fields on the metamorphosis of frogs; Kaeru no hentai katei ni oyobosu jiba no eikyo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Hiwaki, O. [Hiroshima City University, Hiroshima (Japan)

    1996-01-20

    The effect of static magnetic fields on the metamorphosis of frogs was investigated to examine the effect of static magnetic fields on the internal secretion system and nerve system in a living body. In this experiment, the growth and metamorphosis of a Rana Japonica`s larva are inhibited inside the vessel in which a magnet whose upper surface is the N pole was put at the bottom. However, no remarkable change was recognized when a magnet whose upper surface is the S pole was put at the bottom. For a bullfrog, the same result as described above was obtained. The experiment result shows that the vertical upward fields inhibit the growth and metamorphosis of a frog`s larva, but the vertical downward fields do not remarkably act on them. As a result of this experiment, the growth and metamorphosis of a frog are considered to act on the internal secretion system of a tadpole in static magnetic fields when the control by thyroxin is considered. Since the existence of action varies depending on the polarity of vertical magnetic fields, the magnet in a living body is judged to be associated with the internal secretion system of a tadpole. 17 refs., 8 figs.

  10. Studies on surface tension effect for free surface flow around floating models; Futai mokei mawari no jiyu hyomenryu ni oyobosu hyomen choryoku no eikyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K. [Yokohama National Univ., Yokohama (Japan). Faculty of Engineering; Akiba, H. [Toyo Construction Co. Ltd., Tokyo (Japan)

    1996-12-31

    The effect of surface tension on free surface flow around floating models is discussed experimentally and numerically. Three-dimensional free surface flow around vertical circular cylinders floating in a circulating water channel was visually observed, where a surface-active agent was added to water. The results are analyzed using Weber number. The numerical analysis was done for vertical cylinder and CY100 models using the Rankine source method. Weber number of at least around 120 is necessary to eliminate the effect of surface tension from free surface flow around the CY100 model. The numerical analysis for the cylinder model needs simulation with wavelength shorter than that of free surface wave used by the Rankine source method. The model for the resistance test should be at least around 7m long to eliminate the effect of surface tension at Froude number of 0.1 or higher. 15 refs., 12 figs., 2 tabs.

  11. On the sea-covering effect of a huge floating structure on the surrounding water; Choogata futai shuhen no kaisui ni taisuru kaimen shahei no eikyo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Fujino, M.; Kagemoto, H.; Hamada, T. [The University of Tokyo, Tokyo (Japan)

    1996-12-31

    The numerical analysis program based on the difference method for dynamics of sea water with sea-surface displacement, flow rate, salt content and temperature as the parameters is modified to more accurately assess the effects of a huge marine structure on surrounding environment by adding the effects of insolation and boundary conditions of the sea-covering effects of the floating structure. The numerical simulation was done for summer and winter seasons, not in a sea area but using a rectangular bay with the floating structure at the center. A new flow evolves around the floating structure, due to the sea-covering effect. The flow patterns in summer and winter are clearly different, due to difference in insolation. The predicted flow is also sensitive whether stratification is considered or not, by which is meant that it is important what stratification effect is taken into account. Daily insolation changes are accompanied by vertical distribution of water temperature and its temporal change. These effects are also observed under the floating structure which shields insolation. 10 refs., 17 figs., 4 tabs.

  12. Application of information theory to the sensitivity analysis of cogeneration system performance; Johoryo no gainen ni yoru kojenereshon system ni okeru fuka deta eikyo bunseki

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, K.; Ishizaka, T.; Honnma, I. [Tokyo Electric Power Co., Inc. (Japan)

    1996-01-05

    Cogeneration system (CGS) is anticipated by department of energy to play an important role in environment preservation. Cogeneration system`s estimation is depended on the preconditions, heat and electricity load data. Since the recognition of heat and electricity load is difficult, efficiency in load data is demanded repeatedly for the evaluation of cogeneration system. Necessary load factors for the estimation of cogeneration system from the energy department`s point of view as well as what measure may become good while recognizing load factors are investigated in this paper. Based on this, a proposal is made by considering load factors of buildings as a standard for estimation of the system. Further fixed quantity assessment is made with the results of computer simulation. From the obtained results, following observations are noted. Recognization of total load capacity is become very important when base load is introduced considerable amount for houses. Load factor`s information is very important for hotel when heat and electricity are used in balance. It is concluded that irrespective of motor capacity, whole day load factor information is necessary for office buildings. 6 refs., 15 figs., 2 tabs.

  13. Study of the influence of microgravity on the biological cells and molecular level; Seitai saibo bunshi level ni okeru bisho juryoku no eikyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The shape of osteoblast, gene appearance, gene of rice blast, cellular fusion of plants, gravity acceptance mechanism of unicellular organisms, and physiological and immunity functions of mice were investigated under the microgravity condition. The influence of gravity on the vital reaction and the influence of microgravity on the crystallization of vital substances were also investigated. For the observation of osteoblast, the fluorescence dye reacted with Ca was well taken in the cells. The microgravity affected the stability of rice blast, but hardly affected the protoplast culture of mushroom. The reaction of ciliate against the gravity related to the specific gravity difference between cells and outer liquid. The level of adrenaline in blood of mice increased during the drop. The moving speed of trigger waves of chemical parallel slit formed at the BZ reaction under the microgravity became 60% to 80% of that on the ground. In the case of crystallization at the deposition agent concentration of 1% to 4%, the turbidity showing the degree of crystallization changed complicatedly. Nine processes of crystal growth were recognized. 21 refs., 55 figs., 1 tab.

  14. On the sea-covering effect of a huge floating structure on the surrounding water; Choogata futai shuhen no kaisui ni taisuru kaimen shahei no eikyo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Fujino, M.; Kagemoto, H.; Hamada, T. [The University of Tokyo, Tokyo (Japan)

    1996-12-31

    The numerical analysis program based on the difference method for dynamics of sea water with sea-surface displacement, flow rate, salt content and temperature as the parameters is modified to more accurately assess the effects of a huge marine structure on surrounding environment by adding the effects of insolation and boundary conditions of the sea-covering effects of the floating structure. The numerical simulation was done for summer and winter seasons, not in a sea area but using a rectangular bay with the floating structure at the center. A new flow evolves around the floating structure, due to the sea-covering effect. The flow patterns in summer and winter are clearly different, due to difference in insolation. The predicted flow is also sensitive whether stratification is considered or not, by which is meant that it is important what stratification effect is taken into account. Daily insolation changes are accompanied by vertical distribution of water temperature and its temporal change. These effects are also observed under the floating structure which shields insolation. 10 refs., 17 figs., 4 tabs.

  15. Studies on surface tension effect for free surface flow around floating models; Futai mokei mawari no jiyu hyomenryu ni oyobosu hyomen choryoku no eikyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K. [Yokohama National Univ., Yokohama (Japan). Faculty of Engineering; Akiba, H. [Toyo Construction Co. Ltd., Tokyo (Japan)

    1996-12-31

    The effect of surface tension on free surface flow around floating models is discussed experimentally and numerically. Three-dimensional free surface flow around vertical circular cylinders floating in a circulating water channel was visually observed, where a surface-active agent was added to water. The results are analyzed using Weber number. The numerical analysis was done for vertical cylinder and CY100 models using the Rankine source method. Weber number of at least around 120 is necessary to eliminate the effect of surface tension from free surface flow around the CY100 model. The numerical analysis for the cylinder model needs simulation with wavelength shorter than that of free surface wave used by the Rankine source method. The model for the resistance test should be at least around 7m long to eliminate the effect of surface tension at Froude number of 0.1 or higher. 15 refs., 12 figs., 2 tabs.

  16. Visualization study on effects of frequency on acoustic streaming in a pulse tube refrigerator; Parusu kan reitokinai ni yukisareru nijitekina nagare ni oyobosu shuhasu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Shiraishi, M.; Nakano, A. [Mechanical Engineering Laboratory, Tsukuba (Japan); Takamatsu, K.; Murakami, M. [Univ. of Tsukuba, Tsukuba (Japan)

    1999-11-10

    It induces the otherwise secondary and fundamental flow in pulse tube refrigerating machine of an oscillating flow. This secondary flow is connected with the improvement on the performance, if it can be reduced, since it becomes a cause of the usual heat loss. Therefore, we systematically examine the secondary flow induced in the pulse tube refrigerator. Until now, the dependent main factor by sound flow secondary flow and existence of a natural convection secondary flow and angle value of the refrigeration performance clarified the fact by the generation of a natural convection secondary flow. Here, it introduces the result of examining frequency dependence and effect of compression ratio in the visualization experiment on characteristics of a sound flow secondary flow, which always exists. (NEDO)

  17. Experimental investigation of the effects of the car driver`s postures on sleepiness; Chakuza shisei ga nemuke ni oyobosu eikyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Komatsudani, M.; Okamura, C. [Toyo Seat Co. Ltd., Hiroshima (Japan); Nishiyama, S. [Hiroshima City Industrial Technology Institute, Hiroshima (Japan); Nozawa, T.; Nishikawa, K. [Matsuda Motor Corp., Hiroshima (Japan); Hori, T.; Hayashi, M. [Hiroshima University, Hiroshima (Japan)

    1998-05-01

    Effects of car driver`s postures on sleepiness were experimentally investigated. For the measurement method of EEG (electroencephalogram), bipolar induction was adopted, to record Cz and Pz using those at left ear as standard by international 10-20 electrode method. In addition, differential potential was recorded between locations of Cz and Pz. The time constant of EEG was set in 0.3 sec. Brain waves were measured for one minute under open and close eye conditions before and after each test as EEG at the rest. For the measurement of EOG (electro-oculograph), vertical and horizontal eye motions were observed. Induced potential change was measured by attaching silver-silver chloride electrode at the time constant 1.5 sec. For the measurement of SPL (skin potential level), the palm of left hand was used as a measuring point and the left front arm was used as a reference point for attaching electrodes. The danger of sleepiness was provided by the boring driving conditions independent of driver`s postures. There was a difference of relaxation time due to the driver`s postures. It was difficult to avoid sleepiness by adjusting the relative angle between seat and seat back. However, it was found that the angle 110deg was most suitable for avoiding sleepiness. 7 refs., 5 figs., 2 tabs.

  18. Study on the effect of measurement points upon reduced added mass matrix; Shukusho fuka shitsuryo matrix ni okeru kansokuten no eikyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Funaki, T.; Hayashi, S. [Osaka University, Osaka (Japan). Faculty of engineering

    1996-12-31

    It is known in estimating vibration characteristics of a ship that fluid range affects largely a structure. A parameter calculation was performed on node vibration in the vertical direction of a rotating elliptic body such as a ship to investigate the effect of an arranging method of the measurement points upon the result of the analysis. As a result, it is thought that equivalent interval arrangement of 21 measurement points would be sufficient in a lower order side mode of vibrations with less than four nodes. An analysis of calculations performed by arranging measurement points in experimental measurement points revealed that analysis accuracy would not increase even if the number of measurement points is increased if it is done so without considering rotation vector. An experiment was carried out with the number of measurement points increased to verify the above fact, with which the analysis was verified correct. Therefore, as has been forecasted in the previous report, the cause for the analysis accuracy deterioration in a high order mode may be estimated as the effect of the rotation vector. However, since it is not the situation that an analysis considering the rotation vector has been conducted, it cannot be concluded yet that the effect of the rotation vector is the sole cause. 4 refs., 14 figs., 7 tabs.

  19. Effects of UV-B irradiation on growth and physiological activities of cucumber (Cucumis sativus L.) first leaves. Influence of nutrition; Kyuri daiichi honba no seicho to seiri kassei ni oyobosu UV-B shosha no eikyo. Hiryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Murase, K.; Izuta, T.; Totsuka, T. [Tokyo University of Agriculture and Technology, Tokyo (Japan). Faculty of Agriculture; Kondo, N. [The University of Tokyo, Tokyo (Japan); Shimizu, H.; Nakajima, N. [National Inst. for Environmental Studies, Tsukuba (Japan)

    1997-01-10

    The purpose of this study is to clarify the mechanism of growth retardation in UV-B irradiated plants. Effects of UV-B irradiation on the growth of first leaves of fertilized and unfertilized cucumber seedlings were compared. The growth of cucumber seedling first leaves was promoted by fertilization, compared with the unfertilized case. However, it was remarkably suppressed by UV-B irradiation. While, the growth of first leaves of unfertilized plants did not decline significantly by UV-B irradiation. Furthermore, the effects of UV-B irradiation on the growth of first leaves were examined by adding nitrogen, phosphorus, or potassium which are components of fertilizers. All of components promoted the growth, and the degrees of growth suppression were enhanced. Especially, the effects were remarkable in the case of nitrogen addition. It was suggested that the growth suppression of fertilized first leaves by UV-B irradiation would be caused by the decrease in the sensitivity to plant hormones such as cytokinin and the their activities. 23 refs., 6 figs., 1 tab.

  20. Study of coherent optical fiber communication in electromagnetic field. 1. Fundamental experiment in magnetic field; Coherent hikari tsushin eno denjikai no eikyo to taisaku. 1. Jikai no eikyo ni kansuru kiso jikken

    Energy Technology Data Exchange (ETDEWEB)

    Kurono, M.; Isawa, K.; Kuribara, M. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1994-03-01

    Coherent optical fiber communication is an effective method to increase transmission capacity of the existing transmission route. However, it is necessary for this method to control the polarization state of optical signals. Composite fiber optic ground wire (OPGW) is a transmission route that is peculiar to electric power. It is considered that the optical polarization state through OPGW may fluctuate considerably due to the magnetic field generated by electric current. In this paper, it is predicted theoretically that the polarization fluctuation occurs due to the Faraday effect because the magnetic field is formed in the axial direction of the fiber by the spiral flow of electric current along the twisted strand around the fiber. In order to study the effects on the axial magnetic field, carried out is an experiment to add the axial magnetic field to the 10km drum-winding optical core wire through the toroidal coil. Both polarization rotation angle and ellipticity angle are changed up to 1.4 rad by the coil current of 10A. In the AC magnetic field, the bit error rate increases to 10{sup -2}, but it can be improved by the polarization diversity detector. 24 refs., 26 figs., 6 tabs.

  1. WO3 nano-ribbons: their phase transformation from tungstite (WO3·H2O) to tungsten oxide (WO3)

    DEFF Research Database (Denmark)

    Ahmadi, Majid; Sahoo, Satyaprakash; Younesi, Reza

    2014-01-01

    Tungsten oxide (WO3) nano-ribbons (NRs) were obtained by annealing tungstite (WO3·H2O) NRs. The latter was synthesized below room temperature using a simple, environmentally benign, and low cost aging treatment of precursors made by adding hydrochloric acid to diluted sodium tungstate solutions (Na...

  2. A study of electron excitations in CaWO sub 4 and PbWO sub 4 single crystals

    CERN Document Server

    Muerk, V; Mihoková, E; Nitsch, K

    1997-01-01

    The excitation spectra of photo- and thermo-luminescence were compared in the VUV-UV spectral region in CaWO sub 4 and PbWO sub 4 scheelite tungstates. Temperature dependences of emission intensities and decay times were measured for PbWO sub 4 in the 80-300 K range and approximated by a simple phenomenological model. The energy level structure of the emission centre excited state and related kinetic processes are discussed for both tungstates. (author)

  3. In situ synthesis of CdS/CdWO4/WO3 heterojunction films with enhanced photoelectrochemical properties

    Science.gov (United States)

    Zhan, Faqi; Li, Jie; Li, Wenzhang; Yang, Yahui; Liu, Wenhua; Li, Yaomin

    2016-09-01

    CdS/CdWO4/WO3 heterojunction films on fluorine-doped tin oxide (FTO) substrates are for the first time prepared as an efficient photoanode for photoelectrochemical (PEC) hydrogen generation by an in situ conversion process. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet visible spectrometry (UV-vis) and X-ray photoelectron spectroscopy (XPS). The CdS hollow spheres (∼80 nm) sensitized WO3 plate film with a CdWO4 buffer-layer exhibits increased visible light absorption and a significantly improved photoelectrochemical performance. The photocurrent density at 0 V (vs. Ag/AgCl) of the CdS/CdWO4/WO3 anode is ∼3 times higher than that of the CdWO4/WO3 anode, and ∼9 times higher than that of pure WO3 under illumination. The highest incident-photon-to-current-efficiency (IPCE) value increased from 16% to 63% when the ternary heterojunction was formed. This study demonstrates that the synthesis of ternary composite photocatalysts by the in situ conversion process may be a promising approach to achieve high photoelectric conversion efficiency.

  4. Fabrication and characterization of WO3/Ag/WO3 multilayer transparent anode with solution-processed WO3 for polymer light-emitting diodes.

    Science.gov (United States)

    Jeon, Kangmin; Youn, Hongseok; Kim, Seongbeom; Shin, Seongbeom; Yang, Minyang

    2012-05-15

    The dielectric/metal/dielectric multilayer is suitable for a transparent electrode because of its high-optical and high-electrical properties; however, it is fabricated by an expensive and inefficient multistep vacuum process. We present a WO3/Ag/WO3 (WAW) multilayer transparent anode with solution-processed WO3 for polymer light-emitting diodes (PLEDs). This WAW multilayer not only has high transmittance and low resistance but also can be easily and rapidly fabricated. We devised a novel method to deposit a thin WO3 layer by a solution process in an air environment. A tungstic acid solution was prepared from an aqueous solution of Na2WO4 and then converted to WO3 nanoparticles (NPs) by a thermal treatment. Thin WO3 NP layers form WAW multilayer with a thermal-evaporated Ag layer, and they improve the transmittance of the WAW multilayer because of its high transmittance and refractive index. Moreover, the surface of the WO3 layer is homogeneous and flat with low roughness because of the WO3 NP generation from the tungstic acid solution without aggregation. We performed optical simulation and experiments, and the optimized WAW multilayer had a high transmittance of 85% with a sheet resistance of 4 Ω/sq. Finally, PLEDs based on the WAW multilayer anode achieved a maximum luminance of 35,550 cd/m2 at 8 V, and this result implies that the solution-processed WAW multilayer is appropriate for use as a transparent anode in PLEDs.

  5. Microwave-assisted synthesis of Zn-WO3 and ZnWO4 for pseudocapacitor applications

    Science.gov (United States)

    Kumar, R. Dhilip; Andou, Y.; Karuppuchamy, S.

    2016-05-01

    Nanosized Zn-WO3 and ZnWO4 materials have been prepared by microwave irradiation method. The physico-chemical characterization of the prepared nanomaterials was carried out by X-ray diffraction (XRD) and high resolution-scanning electron microscopy (HR-SEM) techniques. The size and shape of the ZnWO4 material can be controlled by changing the temperature. The XRD analysis revealed the formation of monoclinic phase of the calcined nanopowder. The HR-SEM images showed the sphere and plate shape particles. The electrochemical behavior of the ZnWO4 modified electrodes was investigated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques. The synthesized material shows the pseudocapacitance. The specific capacitance of 35.70 F/g was achieved for the Zn-WO3 nanopowder.

  6. Synthesis of S-doped WO3 nanowires with enhanced photocatalytic performance towards dye degradation

    Science.gov (United States)

    Han, Fugui; Li, Heping; Fu, Li; Yang, Jun; Liu, Zhong

    2016-05-01

    In this letter, S-doped WO3 nanowires (S-WO3) were prepared using a hydrothermal method followed by a low-temperature solid-state annealing treatment. The synthesized S-WO3 was characterized by SEM, EDX, XRD, XPS, Raman spectroscopy, UV-vis DRS and photocurrent responses. The results indicated that S could enhance the light harvesting capacity of WO3 nanowires. The photocatalytic performance of the S-WO3 was investigated by photodegradation of methyl orange (MO) under visible light irradiation. Results demonstrated that the photocatalytic activity of the S-WO3 nanowires is much higher than that of pure WO3 nanowires.

  7. Radioactive contamination of ZnWO{sub 4} crystal scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Belli, P. [INFN sezione Roma ' Tor Vergata' , I-00133 Rome (Italy); Bernabei, R., E-mail: rita.bernabei@roma2.infn.i [INFN sezione Roma ' Tor Vergata' , I-00133 Rome (Italy); Dipartimento di Fisica, Universita di Roma ' Tor Vergata' , I-00133 Rome (Italy); Cappella, F. [INFN sezione Roma ' La Sapienza' , I-00185 Rome (Italy); Dipartimento di Fisica, Universita di Roma ' La Sapienza' , 00185 Rome (Italy); Cerulli, R. [INFN, Laboratori Nazionali del Gran Sasso, I-67010 Assergi (AQ) (Italy); Danevich, F.A. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Dubovik, A.M. [Institute for Scintillation Materials, 61001 Kharkiv (Ukraine); D' Angelo, S. [INFN sezione Roma ' Tor Vergata' , I-00133 Rome (Italy); Dipartimento di Fisica, Universita di Roma ' Tor Vergata' , I-00133 Rome (Italy); Galashov, E.N. [Nikolaev Institute of Inorganic Chemistry, 630090 Novosibirsk (Russian Federation); Grinyov, B.V. [Institute for Scintillation Materials, 61001 Kharkiv (Ukraine); Incicchitti, A. [INFN sezione Roma ' La Sapienza' , I-00185 Rome (Italy); Dipartimento di Fisica, Universita di Roma ' La Sapienza' , 00185 Rome (Italy); Kobychev, V.V. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Laubenstein, M. [INFN, Laboratori Nazionali del Gran Sasso, I-67010 Assergi (AQ) (Italy); Nagornaya, L.L. [Institute for Scintillation Materials, 61001 Kharkiv (Ukraine); Nozzoli, F. [INFN sezione Roma ' Tor Vergata' , I-00133 Rome (Italy); Dipartimento di Fisica, Universita di Roma ' Tor Vergata' , I-00133 Rome (Italy); Poda, D.V. [INFN, Laboratori Nazionali del Gran Sasso, I-67010 Assergi (AQ) (Italy); Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Podviyanuk, R.B.; Polischuk, O.G. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Prosperi, D. [INFN sezione Roma ' La Sapienza' , I-00185 Rome (Italy); Dipt. di Fisica, Univ. di Roma ' La Sapienza' , 00185 Rome (Italy); Shlegel, V.N. [Nikolaev Inst. of Inorganic Chemistry, 630090 Novosibirsk (Russian Federation)

    2011-01-21

    The radioactive contamination of ZnWO{sub 4} crystal scintillators has been measured deep underground at the Gran Sasso National Laboratory (LNGS) of the INFN in Italy with a total exposure 3197 kg h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO{sub 4} samples. One of the ZnWO{sub 4} crystals has also been tested by ultra-low background {gamma} spectrometry. The radioactive contaminations of the best ZnWO{sub 4} samples are estimated to be less than 0.002 mBq/kg ({sup 228}Th and {sup 226}Ra), the total {alpha} activity is 0.18 mBq/kg. The {beta} active {sup 65}Zn and the {alpha} active {sup 180}W have been detected in ZnWO{sub 4} crystals. The effect of the re-crystallization on the radiopurity of the ZnWO{sub 4} crystal has been studied. The radioactive contamination of the ceramic components of the set-ups used in the crystals growth has been checked by low background {gamma} spectrometry. Some ideas for future improvement of the radiopurity level of ZnWO{sub 4} crystal scintillators are briefly discussed.

  8. Kinetics and mechanism of dye adsorption on WO3 nanoparticles

    Science.gov (United States)

    Adhikari, Sangeeta; Mandal, Sandip; Sarkar, Debasish; Kim, Do-Heyoung; Madras, Giridhar

    2017-10-01

    Monoclinic WO3 nanoparticles were synthesized by a simple acid catalyzed co-precipitation reaction. Spherical particles with average size ∼55 nm were confirmed from electron microscopy followed by functional, structural and optical characterizations. The adsorption of methylene blue was examined by using WO3 nanoparticles and the capacity was higher than most of the reported studies. The effect of pH and material loading on adsorption was determined. The mechanism of adsorption was examined by XPS and a detailed explanation of surface phenomena was proposed. Regeneration study was carried and a high stability of heat treated WO3 towards adsorption of methylene blue was observed.

  9. Synthesis, Humidity Sensing, Photocatalytic and Antimicrobial Properties of Thin Film Nanoporous PbWO4-WO3 Nanocomposites

    Directory of Open Access Journals (Sweden)

    Markasagayam Visagamani Arularasu

    2017-01-01

    Full Text Available A humidity sensor thin film based on nanoporous PbWO4-WO3 composites has been prepared by spin coating technique with different weight ratio of PbWO4 (Pb and WO3 (WO (PWWO-01, PWWO-82, PWWO-64, PWWO-46, PWWO-28, PWWO-01 and their humidity sensing properties have also been investigated at different relative humidity (RH in the range of 5% - 98% at room temperature with dc resistance. It is found that composite PWWO-28 show best humidity sensing properties with the sensitivity factor value of (Sf 3733. The response and recovery time of humidity sensor are about 50 s and 120 s, respectively. High sensitivity, narrow hysteresis loop, rapid response and recovery, prominent stability and good repeatability are obtained. Synthesized PbWO4-WO3 composites were characterized by power X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, BET and photoluminescence studies. The photocatalytic result demonstrated photocatalytic efficiency of nonporous PWWO-28 composite.  The antimicrobial activity of the composites was determined by disc diffusion method.

  10. Synthesis and photoelectrochemical properties of CdWO{sub 4} and CdS/CdWO{sub 4} nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Weina [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Zheng, Chunhua [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Department of Mathematics and Physics, Officer College of the Chinese People' s Armed Police Forces, Chengdu 610213 (China); Hua, Hao; Yang, Qi; Chen, Lin [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Xi, Yi, E-mail: yxi6@cqu.edu.cn [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Hu, Chenguo, E-mail: hucg@cqu.edu.cn [Department of Applied Physics, Chongqing University, Chongqing 400044 (China)

    2015-02-01

    Graphical abstract: - Highlights: • A facile CHM strategy is employed for the first time to synthesize CdWO{sub 4} nanowire and nanoflower arrays on cadmium foils. • The photoelectrochemical (PEC) properties are measured on the electrodes made of the CdWO{sub 4} nanowire and nanoflower arrays. • The photocurrent density of the nanowire electrode reaches 0.35 mA/cm{sup 2}, which is 3 times as much as that of the nanoflower electrode. • CdS nanoparticles are deposited on CdWO{sub 4} nanowire arrays to form a CdS/CdWO{sub 4} heterojunction to improve the PEC properties. • The remarkably enhanced photoresponse is achieved on the CdS/CdWO{sub 4} which is twice as much as that on the pure CdWO{sub 4} electrode. - Abstract: A facile composite-salt-mediated strategy is employed for the first time to synthesize CdWO{sub 4} nanowire and nanoflower arrays on cadmium foil substrates. The photoelectrochemical (PEC) properties are measured on the electrodes made of the CdWO{sub 4} nanowire and nanoflower arrays under the simulated sunlight illumination. Both electrodes display high sensitive response and photocurrent stability. The photocurrent density of the nanowire arrays electrode reach 0.35 mA/cm{sup 2}, which is about 3 times as much as that of the nanoflower array electrode. To improve the visible light photocurrent response, CdS nanoparticles are deposited on the CdWO{sub 4} nanowire arrays to form a CdS/CdWO{sub 4} heterojunction. Remarkably enhanced photoresponse is observed on the CdS/CdWO{sub 4} heterostructure and the photocurrent intensity is about twice as much as that of the electrode made of the pure CdWO{sub 4} nanowire arrays. The photoelectric mechanism is also discussed by the crystal structure and morphology characterization, optical band gap and carrier mobility analysis. This work presents a new design of a photoelectrochemical device for possible applications in photoelectrolysis of water and solar cells or highly sensitive light detection.

  11. WO3 Nanoplates Film: Formation and Photocatalytic Oxidation Studies

    Directory of Open Access Journals (Sweden)

    Chin Wei Lai

    2015-01-01

    Full Text Available High surface area of tungsten oxide (WO3 nanoplates films was prepared via simple electrochemical anodization technique by controlling the fluoride content (NH4F in electrolyte. The design and development of WO3-based nanostructure assemblies have gained significant interest in order to maximize specific surface area for harvesting more photons to trigger photocatalytic oxidation reaction. This study aims to determine the optimum content of NH4F in forming WO3 nanoplates on W film with efficient photocatalytic oxidation reaction for organic dye degradation by utilizing our solar energy. The NH4F was found to influence the chemical dissolution and field-assisted dissolution rates, thus modifying the final morphological of WO3-based nanostructure assemblies film. It was found that 0.7 wt% of NH4F is the minimum amount to grow WO3 nanoplates film on W film. The photocatalysis oxidation experimental results showed that WO3 nanoplates film exhibited a maximum degradation of methyl orange dye (≈75% under solar illumination for 5 hours. This behavior was attributed to the better charge carriers transportation and minimizes the recombination losses with specific surface area of nanoplates structure.

  12. Anti-tumor activity of self-charged (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles

    Indian Academy of Sciences (India)

    Cao Lin; Cao Jiexin; Wang Cong; Che Ping; Pan De’an; Alex A Volinsky

    2012-10-01

    Non-stoichiometric (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles with anti-tumor activity are synthesized in a sol–gel method by adding excessive Eu3+ and Ca2+ ions to tungsten oxide crystal structure. Colorimetric assay shows that 10 nm (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles can effectively inhibit growth of mammary cancer cells without any harm to normal cells. Nanoparticles are characterized by X-ray diffraction, high resolution transmission electron microscopy and fluorescence optical spectrometry. Nanomaterials, insoluble in synthesized water, have complicated self-charging surfaces that trap mammary cancer cells. Surface self-charging effect is suggested as the inhibition mechanism.

  13. Residual stress in Ni-W electrodeposits

    DEFF Research Database (Denmark)

    Mizushima, Io; Tang, Peter Torben; Hansen, Hans Nørgaard

    2006-01-01

    In the present work, the residual stress in Ni–W layers electrodeposited from electrolytes based on NiSO4 and Na2WO4, is investigated. Citrate, glycine and triethanolamine were used as complexing agents, enabling complex formation between the nickel ion and tungstate. The results show that the type...... of complexing agent and the current efficiency have an influence on the residual stress. In all cases, an increase in tensile stress in the deposit with time after deposition was observed. Pulse plating could improve the stress level for the electrolyte containing equal amounts of citrate...

  14. Crystal Structures of Dy2(WO4)3 and GdY(WO4)3

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Two compounds, Dy2(WO4)3 and GdY(WO4)3; were synthesized by using the standard solid state reaction tech-nique. The crystal structure was determined by powder X-ray diffraction and Rietveld refinement method. It is found thatboth compounds have Eu2(WO4)3-type monoclinic structure, with space group C 2/c, Z = 4. The unit cell parameters ofDy2(WO4)3 are a = 0.75981(1) nm, b = 1.13220(1) nm, c = 1.13254(1) nm, and β= 109.8001(3)°, and those of GdY(WO4)3are a = 0.76175(1) nm, b = 1.13543(1) nm, c = 1.13496(2) nm, and β= 109.8015(13)°. Each W atom has four oxygen near-est neighbors, while each rare-earth atom is surrounded by eight oxygen atoms. WO4 tetrahedra share their four verticeswith REO8 (RE = Dy, Gd, or Y) trigondodecahedra and some REO8 trigondodecahedra share an edge with each other. Thephase transition and the magnetic properties were investigated by differential thermal analysis (DTA) and dc superconduct-ing quantum interference device (SQUID) magnetometer.

  15. Photoluminescence in solid solutions and thin films of tungstates CaWO{sub 4}-CdWO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Taoufyq, A.; Mauroy, V.; Guinneton, F.; Valmalette, J-C. [University of Toulon, IM2NP, UMR CNRS 7334, La Garde, (France); Fiorido, T. [Aix Marseille University, IM2NP, UMR CNRS, 7334, Marseille, (France); Benlhachemi, A. [IBN ZOHR University, Faculty of sciences, Environment and Materials Laboratory, Agadir, (Morocco); Lyoussi, A. [CEA of Cadarache, DEN, Departement of reactors studies, experimental physics, Instrumentation Sensors and Dosimetry Laboratory, (France); Nolibe, G. [Cesigma society, signals and systems, La Garde, (France); Gavarri, J-R. [University of Toulon, IM2NP, UMR CNRS 7334, La Garde, (France)

    2015-07-01

    In this study, we present two types of studies on the luminescence properties under UV and X-ray excitations of solid solutions Ca{sub 1-x}Cd{sub x}WO{sub 4} and of thin layers of CaWO{sub 4} and CdWO{sub 4}. These tungstate based solid solutions are susceptible to be integrated into new radiation sensors, in order to be used in different fields of applications such as reactor measurements, safeguards, homeland security, nuclear nondestructive assays, LINAC emission radiation measurement. However these complex materials were rarely investigated in the literature. One first objective of our studies was to establish correlations between luminescence efficiency, chemical substitution and the degree of crystallization resulting from elaboration conditions. A second objective will be to determine the efficiency of luminescence properties of thin layers of these materials. In the present work, we focus our attention on the role of chemical substitution on photon emissions under UV and X-ray irradiations. The luminescence spectra of Ca{sub 1-x}Cd{sub x}WO{sub 4} polycrystalline materials have been investigated at room temperature as a function of composition (0≤x≤1). In addition, we present a preliminary study of the luminescence of CaWO{sub 4} and CdWO{sub 4} thin layers: oscillations observed in the case of X-ray excitations in the luminescence spectra are discussed. (authors)

  16. Photocatalytic properties of h-WO3 nanoparticles obtained by annealing and h-WO3 nanorods prepared by hydrothermal method

    Science.gov (United States)

    Boyadjiev, Stefan I.; Nagy-Kovács, Teodóra; Lukács, István; Szilágyi, Imre M.

    2016-03-01

    In the present study, two different methods for preparing hexagonal WO3 (h-WO3) photocatalysts were used - controlled thermal decomposition and hydrothermal synthesis. WO3 nanoparticles with hexagonal structure were obtained by annealing (NH4)xWO3-y at 500 °C in air. WO3 nanorods were prepared by a hydrothermal method using sodium tungstate Na2WO4, HCl, (COOH)2 and NaSO4 precursors at 200 °C. The formation, morphology, structure and composition of the as-prepared nanoparticles and nanorods were studied by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX). The photocatalytic activity of the h-WO3 nanoparticles and nanorods was studied by decomposing methyl orange in aqueous solution under UV light irradiation.

  17. FY 1995 development of fluorinated hydriding alloys with multi functional and functionally-graded surface and their application to energy conversion devices; 1995 nendo keishagata fukugo kino wo hyomen ni motsu suiso kyuzo gokin no kaihatsu to energy henkan gijutsu eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The project is the extended researches of a fluorination technique invented by the project leader (Suda) for improving the surface properties and characteristics of conventional hydriding alloys from the following viewpoints; (1) To investigate the roles of fluorinated surface during hydrogen uptake both in the gas-solid and the electrochemical reactions. (2) To elucidate the factors which increase the protective nature of the surface. (3) To develop a material design procedure for synthesizing thin layer of functionally graded surface which is composed of metallic Ni and the fluoride compound. (1) An advanced fluorination technique was developed to incorporate metallic Ni in the surface fluoride layer. (2) Metallic Ni was successfully distributed in a functionally graded manner in the Surface fluoride layer. (3) Through the technique developed, the following properties and characteristics were successfully donated in the fluorinated hydriding alloys such as AB{sub 5}, AB{sub 2}, and AB; (3-1)Surface oxides which act as the resistant layer to the hydrogen up take was completely eliminated to result in the enhancement of the initial activation characteristics. (3-2) Hydrogen selectivity and permeability was greatly improved. (3-3) Surface protective nature against the impurity gases and contaminants was significantly improved. (3-4) Initial activation characteristics both in the gas-solid and the electrochemical reactions were distinguishably improved. (3-5) Fluorinated surface was found to function as the catalyst for a methanation reaction between the CO{sub 2} gas adsorbed over the fluorinated surface and the monatomic hydrogen absorbed in the metal lattice of the crystalline structure of the hydriding alloys. (4) A technique was developed for increasing the specific surface area and decreasing the specific surface diameter of the fluorinated hydriding alloy articles. (NEDO)

  18. Large single crystal growth of MnWO4-type materials from high-temperature solutions

    Science.gov (United States)

    Gattermann, U.; Röska, B.; Paulmann, C.; Park, S.-H.

    2016-11-01

    A simple high-temperature growth apparatus was constructed to obtain large crystals of chemically gradient (In, Na)-doped MnWO4solid-solutions. This paper presents the crystal growth and characterisation of both MnWO4and epitaxially grown (In, Na): MnWO4crystals on MnWO4. These large monolithic crystals were made in two steps: A MnWO4 crystal was grown in the crystallographic main direction [001] applying the Czochralski method, followed by the top seeded growth of (In, Na): MnWO4 solid-solutions with an oriented seed crystal of MnWO4. Such a monolithic crystal will serve to fundamental investigation of coupling properties at boundaries between various multiferroic MnWO4-typesolid-solutions.

  19. Structure and photocatalytic performance of layered HNbWO6 nanosheet aggregation

    KAUST Repository

    Hu, Li-Fang

    2015-12-10

    Layered HNbWO6HNbWO6 nanosheet aggregation (e-HNbWO6e-HNbWO6) has been assembled by HNbWO6HNbWO6 nanosheet via an exfoliation-restaking route. The as-prepared samples are characterized by means of powder x-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, laser Raman spectroscopy, ultraviolet-vis diffuse reflectance spectroscopy, and N2N2 adsorption-desorption isotherms. The photocatalytic performances of the as-prepared samples are evaluated by degradation of methylene blue (MB). The results revealed that e-HNbWO6e-HNbWO6 has a specific surface area of about 156.5  m2 g−1156.5  m2 g−1, and exhibits a relatively excellent photocatalytic performance for degradation of MB under UV light.

  20. Effect of grain size on amplitude-dependent internal friction in polycrystalline copper. Do takessho no naibu masatsu no shinpuku izon sei ni oyobosu kessho ryukei no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Goto, H.; Nishino, Y.; Asano, S. (Nagoya Inst. of Technology, Nagoya (Japan))

    1991-08-20

    In this research, amplitude-dependency of internal friction was measured on various polycrystalline copper of varying grain size. Furthermore, the measurement data of amplitude-dependency of internal friction were analyzed from the phenomenological standpoint and microplastic strain was calculated as a function of stress. The obtained correlation between microplastic strain and stress corresponded to the stress-strain curve obtainable from normal tensile tests. Hence, comparing with the Hall-Petch relation, the relationship between flow stress and grain size in the microplastiic zone was discussed. The obtained results are summarized as follows: When grains were refined, amplitude dependency of internal friction was inhibited. As a result of the analysis of the data obtained, it was found that the flow stress in the microplastic zone increased following refining of grains. This agreed qualitatively with the macro deformation obtained from normal tensile tests. The grain size dependency of flow stress in the microplastic zone did not follow the normal Hall-Pitch relation, but the plastic strain increased, the dependency moved towards it. 16 refs., 4 figs.

  1. Study on the effect of micro-gravity on bio-functions; Seitai kino eno bisho juryoku no eikyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The effect of micro-gravity on bio-functions and vital reaction was studied using the facility of Underground Gravity-free Experiment Center Co. On the effect on osteoblast shape and gene expression, although fluorochrome reacting with Ca was well taken into cells, no significant difference in Ca content in cells was observed before/after falling. Expression of genes related to cell propagation was controlled under micro-gravity. Protoplast fusion of Lentinus was unaffected by micro-gravity. The mRNA fragments of gravity sensitive mutant of rice plant were affected by micro-gravity. Paramecium was set swimming in solutions with different specific gravities. The reaction behavior of Paramecium was affected by the difference in specific gravity between cell bodies and solutions. The water content metabolism functions of a mouse with needle stimulus, in particular excretory, were slightly promoted by micro- gravity. The cortisol level in blood of a falling mouse group rose showing strong stress. As the preliminary study on the geotaxis of insects, motion of bagworm was observed. 12 refs., 38 figs., 4 tabs.

  2. Effect of heat treatment changes on swelling treatment of coal; Sekitan no bojun shori sayo ni oyobosu netsushori henka no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Satsuka, T.; Mashimo, K.; Wainai, T. [Nihon University, Tokyo (Japan). College of Science and Technology

    1996-10-28

    Discussions were given on effects of heat treatment at relatively low temperatures as a pretreatment for coal liquefaction on coal swelling and hydrogenolysis reaction. Taiheiyo coal was heated to 200{degree}C for one hour as a pretreatment. The attempted heating methods consisted of four steps of rapid heating (6.7{degree}C/min)quenching (20{degree}C/min), rapid heating/natural cooling (0.7{degree}C/min), heating (1.0{degree}C/min)/quenching, and heating/natural cooling. The swelling treatment was composed of adding methanol benzene into heat treated coal, and leaving it at room temperature for 24 hours. The hydrogenolysis was carried out by using a tetralin solvent and at an initial hydrogen pressure of 20 kg/cm{sup 2} and a temperature of 350{degree}C and for a time of one hour. Hydrogenolysis conversion in the heat treated coal was found lower than that of the original coal because of generation of liquefaction inactive components due to thermal polymerization. When the heat treated coal is swollen by using the solvent, gas yield from the hydrogenolysis reaction decreased due to gas suppression effect, and the conversion was lower than that of the original coal. Heat treatment suggests densification of the coal structure. Swollen coal shows no conspicuous difference in the heat treatment methods against the hydrogenolysis due to the swelling effect. 3 refs., 5 figs., 1 tab.

  3. Effects of lithium iodide doping on devolatilization characteristics of brown coals; Yoka lithium no tenka ga kattan no kanetsu henka katei ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Muraoka, J.; Kumagai, H.; Hayashi, J.; Chiba, T. [Hokkaido University, Sapporo (Japan)

    1996-10-28

    In order to discuss effects of lithium iodide (LiI) doping on condensation structure of brown coals during heating, spectral changes were measured by using an in-situ FT-IR. It was found that the LiI doping accelerates weight reduction due to heating, and the doping effect is affected by coal structure. Both of Loy Yang (LY) coal and its LiI doped coal (DLY) had absorption intensity of the FT-IR spectra decreased with rising temperature, and the absorption center belonging to an OH group shows different shifts between the LY and DLY coals. This indicates that the LiI doping has affected the change in hydrogen bonding patterns associated with heating. Both of South Banko (SB) and LY coals had the absorption spectral intensity in the OH group decreased as the weight reduction (conversion) rate increased. Reduction in the OH groups associated with heating is caused by volatilization and condensation reaction in light-gravity fraction. However, in the case of equal conversion rate, the LiI doped coal shows higher spectral intensity than the original coal, with the LiI doping suppressing reduction in the OH groups. It appears that the doping suppresses the condensation reaction between the OH groups. 2 refs., 6 figs., 1 tab.

  4. International symposium on environmental impacts of advanced alternative to CFC; CFC shinki daitai busshitsu no kankyo eikyo ni kansuru kokusai symposium hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-07

    The international symposium on environmental effects of new CFC substitutes was held in Tsukuba City, Ibaraki Pref. on February 7-9, 1996, and 19 papers were made public. In Session 1 (Plenary lecture), reports were made on Global warming and climate change: a review of recent studies; Stratospheric ozone, CFCs, and CFC-substitutes: an update, etc. In Session 2, Measurements of OH rate constants for advanced refrigerants as well as HCFCs and HFCs; The reaction rate of CFC alternatives with OH radical; Experimental and estimated rate constants: reactions of hydroxyl radicals with several halocarbons, etc. In Session 3, Measurement of uptake coefficients of some acetyl halides and fluorinated ethers into water; Mass transfer at the air/water interface: removal processes of halocarbonyl compounds; Heterogeneous reactions of fluorinated ethers on allophane or titanium dioxide, etc. In Session 4, papers were reported on model calculations relating to the global warming.

  5. Effect of odors from coniferous woods on contingent negative variation (CNV); Shinyojuzai no nioi ga zuihansei insei hendo (CNV) ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Terauchi, F. [Chiba University, Chiba (Japan); Kubo, M.; Aoki, H. [Chiba University, Chiba (Japan). Faculty of Engineering; Ogama, T. [Chiba University, Chiba (Japan). Faculty of Education

    1996-04-15

    In order to clarify the effect of odors of seven coniferous woods on human, contingent negative variation (CNV) and electroencephalogram (EEG) were measured. Four of the species used, hinoki (Chamaecyparis obtuse), sugi (Cryptomeria japonica), akamatsu (Pinus densiflora), and hiba (Thujopsis dolabrata var.hondai), were grown in Japan, and three of them, Alaska cedar (Chamaecyparis nootkatensis), Douglas fir (Pseudotsuga menziesii), and western red cedar (Thuja plicata), were grown in the United States. The concentrations of their wood odors were analysed by gas-liquid chromatography. The total concentration of monoterpene hydrocarbon in the wood odors was held to less than 3ppb. The amplitudes of early components of CNV and the {alpha}/{beta} wave ratio of EEG at the frontal (Fz) and central (Cz) regions between in the presence and absence of wood odors were compared. 5 male and 5 female volunteers ranging in age from 20 to 26 were examined. The result obtained are summarized as follows: (1) In the presence of wood odors, the early CNV amplitudes at Fz decreased at a statistical level of significance of 5% or better. (2) The {alpha}/{beta} wave ratio of EEG increased significantly at Cz with bibs wood odor (p<0.01). (3) The decrease of the early CNV amplitude at Fz is related to the concentration of {alpha}-pinene in the wood odors. 19 refs., 7 figs., 5 tabs.

  6. Study on the performance improvement of multiblade fans. Effects of suction cones; Tayoku fan no seino kaizen ni kansuru kenkyu. Suction cone no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kuratani, F.; Ogawa, T. [Hyogo University of Teacher Education, Hyogo (Japan); Yamamoto, S.

    1999-07-25

    In order to improve the performance of a multiblade fan, the effects of three types of suction cones of the fan casing on the fan efficiency and noise are investigated experimentally. The first type of the suction cone is the insertion type, which is inserted into the inside of the fan impeller. The second type is the extrusion type, which extrudes outside from the casing surface. The third type is the combination type of two types. The results of those three types are compared with those of the commonly used suction cone. The followings are made clear: (1) The insertion type and the extrusion type are effective in improving the efficiency and reducing noise. (2) The optimal lengths of the insertion and the extrusion exist. (3) The combination type is more effective in improving the efficiency. (4) The combination type with the skewed cutoff of the fan casing shows the best effect. (author)

  7. Temperature effect on corrosion fatigue strength of coated ship structural steel; Zosen`yoko tosozai no fushoku hiro kyodo ni okeru ondo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Takanashi, M.; Fuji, A.; Kojima, M.; Kitagawa, M. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan); Kobayashi, Y. [Ship Research Inst., Tokyo (Japan); Kumakura, Y.

    1997-08-01

    The corrosion fatigue life was obtained using uncoated and tar epoxy resin specimens to clarify the temperature effect. The life curve for corrosion fatigue of machined and uncoated steel in the air and sea was obtained. The fatigue strength of uncoated steel largely decreases in the sea and breaks even in the nominal stress range of less than 1/2 of the fatigue limit in the air. The effect of temperature on the coated steel is represented by a corrosion coefficient. The steel coated at 25{degree}C is 1/1.03 to 1/1.13 at 40 to 60{degree}C. This showed that the fatigue strength decreases when the temperature exceeds 25{degree}C. However, it has not such tendency and significance that are represented quantitatively. There is a slight difference in the short-life area between the crack generation life and breaking life. However, the long-life area has no significance that influences the whole evaluation. In the long-life corrosion fatigue, the crack occurs from the corrosion pit due to the exposure below the coated film and progresses in the base material before the coated film is destroyed. The effect of the corrosion pit remarkably appears at a low-stress level. 14 refs., 14 figs., 4 tabs.

  8. Environmental endocrine disruptors and developmental abnormalities in wildlife; Kankyo horumon (gaiinsei naibunpi kakuran kagaku busshitsu) no kankyo seibutsu ni taisuru eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Iguchi, T. [Yokohama City Univ., Yokohama (Japan)

    1998-04-15

    The environmental endocrine disruptor, or the so-called environmental hormone, is outlined. Hormones are secreted from endocrine glands in trace amounts, transported by blood, and exert influence on the target organs and distal cells, this to sustain constancy in living organisms. There are two types: peptide hormones which are rows of amino acids and steroid hormones which are composed of cholesterol. Endocrine disruptors are chemical substances discharged into the environment which, once taken into human organisms, disrupt endocrine systems, some acting like female sex hormones and others resisting male sex hormones. Many a wild animal are found affected by them. They are accumulating in human organisms too. Synthesized chemical substances such as DDT, PCB, dioxins, and alkylphenols present in the water system affect a fish by disrupting its endocrine, immunity, nerve, growth, and regeneration. Embryos and larvae are quite susceptible, easy to turn abnormal. Voices are high across the world for the study of environmental endocrine disruptors. Introduced in this report are some animal experiments, typical cases of impact on the ecosystem, and systems for detecting environmental endocrine disruptors. 36 refs., 1 tab.

  9. Influence of smectites on resistivity of rocks and soils; Smectite nendo kobutsu ga ganseki dojo no hi teiko ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Takakura, S.; Nishizawa, O.; Aoki, M. [Geological Survey of Japan, Tsukuba (Japan); Kozake, K. [University of Tsukuba, Ibaraki (Japan)

    1996-10-01

    This paper illustrates the measurement results of resistivity for specimens including smectite clay minerals artificially synthesized, and also discusses the influence of smectites on resistivity. Three kinds of bentonites, i.e., KN-1, Kawasaki ore, and Kawasaki Sanhaku, were used for preparing smectites. The KN-1 is Na type smectite, the Kawasaki ore is Ca type smectite, and the Kawasaki Sanhaku is acid clay. It is well known that smectites lower the resistivity of rocks. However, the experimental results suggested that the degree of decreasing the resistivity depends on the kind of smectites. The effect of decreasing the resistivity by the KN-1 was much superior to the other smectites. For the KN-1, a thick electrical double layer was formed by Na ions in the interlayers, which resulted in the larger effect of decreasing the resistivity. Swelling capacity and cation exchange capacity (CEC) of the KN-1 were large, which agreed with the above mentioned consideration. Reversely, it was considered that smectites having larger effect of decreasing the resistivity exhibited larger swelling capacity and CEC. 4 refs., 3 figs.

  10. Effects of austempering heat treatment conditions on fracture toughness of austempered ductile cast iron; Kyujo kokuen chutetsu no hakai jinsei ni oyobosu austemper shori no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Y.; Arai, M. [Musashi Institute of Technology, Tokyo (Japan)

    1996-03-25

    Discussions were given in various manners to learn effects of treatment conditions with respect to fracture toughness of austempered ductile cast iron. Austenitizing temperature and isothermal transforming conditions that result in comprehensively most excellent fracture toughness including tensile strength were 1173 K and 648 K - 3.6 ks, respectively. The austenitizing temperature as low as 1123 K reduces quantity of residual austenite, resulting in residual inclusion of free ferrite in the structure. If as high as 1223 K, reduction in the fracture toughness is caused under any condition as a result of increase in unstable austenite and growth of austenite into coarse particles. With respect to the isothermal transforming conditions, high fracture toughness may be achieved at a relatively high temperature. However, a structure that has been transformed from austenite to bainite causes a secondary reaction in a short time, and deposits particulates of cementite and graphite, leading to a prediction of decrease in the fracture toughness. Therefore, it is preferable that the treatment time is decreased in order to suppress the secondary reaction. 9 refs., 10 figs., 7 tabs.

  11. Influence of slit depth on impact value of ferritic nodular graphite cast iron. Feraito kyujo kokuen chutetsu no shogekichi ni oyobosu suritto fukasa no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sunada, H. (Himegi Inst. of Technology, Hyogo (Japan). Faculty of Engineering)

    1992-10-15

    Impact experiment and fracture surface observations were carried out in order to study the effect of slit depth on the impact value during austempering of ferrite spheroidal graphite east iron. The tensile strength has been increased by austempering, however the impact value was not improved. The bending strength of slit bottom for each structure has been less influenced by slit depth, and it has been almost similar, The value obtained by the multiplication by binding coefficient has been higher than yield strength in case of ferrite structure, and it has been lower in case of bainitic structure. Cleavage facets along with the large dimples originating from graphites and small dimples from inclursions, have been observed on the impact fracture surface of ferrite structure, however in general, the fracture has been ductile. The deformation around the graphite has been small for bainitic structure, pseudo brittleness type fracture surface is formed, and has been less rough compared to ferrite structure. 9 refs., 8 figs., 1 tab.

  12. Effect of tempering treatment on toughness of austempered ductile iron; Austemper kyujo kokuen chutetsu no jinsei ni oyobosu yakimodoshi no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, S.; Kobayashi, T. [Toyohashi University of Technology, Aichi (Japan)

    1994-07-25

    Austempered ductile iron (ADI) is increasing its application to high strength members as a cast iron material that has both high strength and ductility. In order to investigate the effect of internal strain generated during austempering treatment, the present study investigates the effect of tempering on its toughness, and performs metal structural discussions. The result may be summarized as follows: the cause to bring about change in toughness given by the tempering is mainly the increase or decrease in the ductility, and the optimal tempering condition was found 723K {times} 10 min in the present study; the tempering process of ADI consists of two stages, whereas in the first stage the dislocation of high density introduced by the austempering treatment is reduced mainly in the ferrite, and the toughness improves as a result of increased ductility; in the second stage, deposition of carbide (Fe3C) is developed in association with decomposition of the residual austenite, when the toughness decreases. 18 refs., 11 figs., 1 tab.

  13. Effect of partial solution treatment on martensitic transformation of 12%Cr steels; 12% Cr ko no martensite hentai ni oyobosu bubun yotaika shori no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiyama, T.; Takai, S. [Kyushu University, Fukuoka (Japan)

    1996-12-01

    When high chromium martensitic steels are subjected to partial solution treatment in (austenite+M23C6, carbide) two -phase region, not only the coarsening of austenite grains is effectively suppressed by insoluble-carbide particles, but also martensitic structure, which has formed during cooling, is refined through the treatment. In this study, the mechanism of refining of martensitic structure was discussed in Fe-12%Cr-C ternary alloys by investigating the relation between Ms temperature and solution treatment conditions, and the effect of insoluble-carbide particles on the substructures such as martensite-lath or -block. The Ms temperature of steels with full solution treatment simply depends on the content of C and Cr, but that of steels with partial solution treatment is dependent on the effective chemical composition of matrix, which is evaluated by taking the amount of C and Cr in insoluble-carbide away from their total content. Refining of martensite-block structure within grains is not caused directly by insoluble-carbide particles, but done indirectly through the refining of austenite grain size. While, on the martensite-lath structure, insoluble-carbide particles supply nucleation sites for laths, and work also as obstacles for growing laths. As a result, martensite-laths in steels with partial solution treatment are divided finely by insoluble carbide particles, and the arrangement of laths is tend to be confused. 14 refs., 10 figs., 1 tab.

  14. Effect of low temperature plasma treatment on dimensional stability of wool fabrics. Yomo orimono no sunpo fuanteisei ni oyobosu teion plasma shori no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Goto, T.; Wakita, T. (Kyoto Institute of Technology, Kyoto (Japan). Faculty of Engineering and Design); Hosotani, T. (Unitika Research Laboratories Inc., Osaka (Japan))

    1991-07-10

    This report describes the effect of low temperature plasma treatment, which has been developed for fabric processing, on wool fabrics. In the experiment, wool fabrics were treated by low temperature plasma using O{sub 2}, Ar, CH{sub 4}, CHF{sub 3}, and CF{sub 4}. Low temperature plasma treatment did not influence moisture regain of wool fabrics, but influenced hygral expansion. There was no difference in the area of low humidity, however, dimensional change was restricted by half in the area of high humidity. Low temperature plasma treatment also improved felt shrinkage caused by home laundering. Moreover, it was found that friction coefficient of wool fabrics increased remarkably after low temperature plasma treatment. Therefore, the subsequent reactive silicone elastmer softening agent was used for finishing process after low temperature plasma treatment. As a result, wool fabrics hardened by low temperature plasma treatment regained their soft condition and washing resistant shrinkage percentage was also improved. Thus this treatment was proved to be used practically. 15 refs., 6 figs., 5 tabs.

  15. Effect of temperature on bending creep of wood during moisture adsorption; Mokuzai no kyushitsu katei no mage creep ni oyobosu ondo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Tokumoto, M.; Takeda, T.; Nakano, T. [Shinshu University, Nagano (Japan). Faculty of Agriculture

    1996-04-15

    The effect of temperature (20-80{degree}C) on the bending creep of wood during moisture adsorption (7 % {yields} 16 %) and desorption (16 % {yields} 7 %) was investigated by using small beams of buna (Fague crenata Blume) and hinoki (Chamaecyparis obtusa Endl.) wood. The test specimens were 120 men radially, 3 mm tangentially and 10 mm longitudinally. The span was 100 mm and the prescribed bending loads fitting to the test temperature were applied at the center of span. The final equilibrium moisture contents were attained in one step (fast) and in 7-8 steps (slow) by suitable humidity schedules in a testing chamber. Creep during moisture desorption was not dependent on temperature between 20{degree}C and 80{degree}C. On the other hand, creep during moisture adsorption was dependent not only on temperature but also on time and the range of moisture content. The difference in temperature dependence of creep between the adsorption and desorption period may be explained based on the behavior of the amorphous region composed of molecular network. Some possible explanations are given in terms of the response of the molecular network structure in the amorphous region during desorption and adsorption. 9 refs., 7 figs.

  16. Effect of fuel composition on poly aromatic hydrocarbons in particulate matter from DI diesel engine; Particulate chu no PAH ni oyobosu nenryo sosei no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, S.; Tatani, T.; Yoshida, H.; Takizawa, H.; Miyoshi, K.; Ikebe, H. [COSMO Research Institute, Tokyo (Japan)

    1997-10-01

    The effect of fuel composition on poly aromatic hydrocarbons (PAH) in particulate matter from DI diesel engine was investigated by using deeply desulfurized fuel and model fuel which properties are not interrelated. It was found that the deeply desulfurized fuel have effect on reducing PAH emissions. Furthermore, it was suggested that poly aromatics in the fuel affect PAH emissions and the influence of tri-aromatics in the fuel was promoted by the coexistence of mono-aromatics or naphthene. PAH formation scheme from each fuel component was proposed by chemical thermodynamic data. 4 refs., 8 figs., 3 tabs.

  17. Effects of gasoline properties on exhaust emission and photochemical reactivity; Gasoline seijo ga haiki gas sosei, kokagaku hannosei ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, R.; Usui, K.; Moriya, A.; Sato, M.; Nomura, T.; Sue, H. [Petroleum Energy Center, Advanced Technology and Research Institute, Tokyo (Japan)

    1997-10-01

    In order to investigate the effects of fuel properties on emissions, four passenger cars were tested under Japanese 11 and 10-15 modes using two series gasoline fuels. The test results suggest that the distillation property (T90) affects A/F ratio which in turn influences exhaust emissions. The results of regression analysis show that both ozone forming potential and air toxics are highly corrected with the composition of aromatic hydrocarbons in gasoline. 3 refs., 10 figs., 6 tabs.

  18. Effects of MTBE blended diesel fuel on diesel combustion and emissions; MTBE kongo keiyu ga diesel nensho haiki ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Shundo, S.; Yokota, H.; Kakegawa, T. [Hino Motors, Ltd., Tokyo (Japan)

    1997-10-01

    The effects of MTBE (Methyl-t-butyl ether) blended diesel fuel on diesel combustion and emissions were studied. In conventional diesel combustion, the testing mode was carried out in conformity with the Japanese 13 mode. Furthermore, this fuel was applied to a new combustion system (Homogeneous Charge Intelligent Multiple Injection). MTBE blended diesel fuel is more effective in the case of new combustion system and very low NOx, PM capability is suggested. 6 refs., 6 figs., 2 tabs.

  19. Effect of solute content on plasma nitriding behavior of Fe-Cr alloys; Fe-Cr gokin purazuma chikka kyodo ni oyobosu yoshitsu nodo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Weiyan; Okada, S. [Okayama Univ., Okayama (Japan). Graduate School; Takada, J. [Okayama Univ., Okayama (Japan). Faculty of Engineering; Kuwahara, H. [Research Inst. for Applied Science, Kyoto (Japan); Nishikawa, S.; Hama, T. [Kogi Ltd., Hyogo (Japan)

    1996-03-15

    It has been clarified by the present authors, based on the plasma nitriding of Fe-Cr alloys and Fe-Ti alloys carried out at the temperature under 550{degree}C hitherto, that an internal nitriding layer is formed due to the fine dispersion of the particles of Cr nitride and Ti nitride in {gamma}{prime} Fe4N layer on the specimen surface. In this study, the plasma nitriding of Fe-Cr alloys are carried out at 650{degree}C, and the effects of the solute (Cr) content on the structures, nitride and the thickness distribution are examined. The main results obtained therefrom are indicated hereafter. In accordance with the observation on the cross-sectional structure of the alloys, only the nitriding layer deduced as the dispersion and precipitation of the particles of Cr nitride from {alpha}-Fe of the mother phase is formed, while {gamma}{prime}-Fe4N layer, which is found at the temperature under 550{degree}C, is not formed. The nitride of Cr generated in the nitriding layer is CrN in all Fe-Cr alloys. The hardness in the nitriding layer is constant and increases with the increase of Cr content. 13 refs., 6 figs.

  20. Influence of hydrothermal flux on arsenic geochemical balance of seawater. Kaisuichu no hiso no chikyu kagaku balance ni taisuru nessui no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Shikazono, N. (Keio University, Tokyo (Japan). Faculty of Science and Technology)

    1993-11-05

    It was recently confirmed that a large quantity of hydrothermal solution has been gushing out at back-arc basins and ocean ridges. Therefore, effects of the hydrothermal solution on the seawater composition have been studied in many ways. In this report, balance of arsenic in seawater is investigated since arsenic has a higher concentration in hydrothermal solution than in seawater. Trial calculations are conducted based on the arsenic concentration in hydrothermal solution and the seawater/hydrothermal-solution circulation amount. As a result, it is assumed that the hydrothermal input flux from island-arc/back-arc basins into seawater is much higher than that from ocean ridges. The total hydrothermal input flux is (0.28-5.36) [times] 10[sup 11]g/year, which is equivalent to or higher than that of river flux. The total input flux of arsenic including input from volcanic gas is in the same order as the output flux of arsenic due to the pyrite formation within submarine sediment. It is estimated that the subduction flux into the depth of the crust is lower than the hydrothermal flux from island-arc/back-arc basins. Therefore, it is inferred that most of the arsenic subducted into the crust would be circulated in the ocean. 23 refs., 2 tabs.

  1. Effects of ultra-violet ray and aqueous environment on deformation behavior of spider threads; Kumoito no henkei kyodo ni oyobosu hikari oyobi mizu kankyo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kitagawa, M.; Katsumi, S. [Kanazawa University, Ishikawa (Japan). Faculty of Engineering; Wako, Y. [Hachinohe Institute of Technology, Aomori (Japan). Laboratory of Food Technology

    1998-01-15

    As a series of the studies on the mechanical properties of spider threads, the effects of ultra- violet rays (UV) and water was investigated using drag lines of Nephila clavata (Jorougumo) and capture threads of Argiope amoena (Koganegumo). It was shown for the effect of water that (1) the drag line was contracted as soon as immersed in water (super contraction), while the capture thread was not so contracted and the viscid droplets attached to it were dissolved in water, and (2) the super contracted drag fine behaved like a capture thread with a j shaped load-draw ratio curve. For the effect of UV, it was found that (1) the degradation due to UV irradiation with short wave length was accelerated more than that with long one and (2) the degree of degradation for each wave length was governed by the integrated irradiation energy of UV. 9 refs., 8 figs.

  2. Effects of ultraviolet rays and acid rain on strength of spider silk; Kumo ito no kyodo ni oyobosu shigaisen oyobi sanseiu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kitagawa, M.; Sasagawa, H. [Kanazawa Univ., Ishikawa (Japan). Faculty of engineering; Kawagoe, M. [Toyama Prefectural Univ., Toyama (Japan)

    1995-12-15

    Spider silk, differing to the synthetic fibers yarned at high temperature or using hazardous solvents, is a fiber in the body of animal and the process itself is safe. Again, the silk is made of up protein and is kind to the environment because does not cause pollution even after disposal. Also, it is a material of interest as a strong fiber having high tensile strength reaching to 2000 MPa. Accordingly, spider silk can be taken as an effective industrial material if the mass production of the fiber is possible by genetic engineering. In previous report, the mechanical properties of dragline silk spewed out from the same silk gland as the warp, a kind of silk spewed out by Nephila clavata, so called Jorogumo, were studied. In this report, the deformation behavior of circular net made by Jorogumo and applicability to environmental evaluation are under study, and effect of acid environment and ultraviolet rays on the mechanical properties of spider silk are studied. As a result, it was revealed that ultraviolet rays degraded the spider silk, and further, promoted the degradation when the acid rain acted at the same time. 16 refs., 11 figs.

  3. Influence of turbid waters of phytoplankton biomass and flora in reservoirs; Dakusui ryunyu ga dam ko no shokubutsu plankton ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, I.; Okugawa, K.; Takakura, M. [Toyama Prefectural University, Toyama (Japan). College of Technology

    1996-10-10

    The purpose of this study was to examine the influence of turbid waters on phytoplankton biomass and flora in reservoirs. We examined water quality and phytoplankton in Tedori and Konade Reservoirs. Phytoplankton biomass increased and its flora changed when the turbidity of the lake waters reached about 20mg{center_dot}l{sup -1} or above due to inflow of turbid waters or after that time. The flagellated chlorophytes, such as Pandorina, Carteria and Chlamydomonas, increased at that time. Concentration of T-P increased with the rise of turbidity (r{ne}0.8). From the relationship between T-P and D-P (dissolved T-P), it was considered that most of T-P was the insoluble type which was adsorbed on the mud particles in Tedori Reservoir. In Konade Reservoir, D-P was among the values from 0.004 to 0.012 mg{center_dot}l{sup -1} in spite of the concentration of T-P, and Anabaena of cyanophytes, other than Chlamydomonas of flagellated chlorophytes, increased in the case of turbidity above 20 mg{center_dot}l{sup -1}. It was presumed that the difference of flora at the turbidites above 20 mg{center_dot}l{sup -1} between the reservoirs might be due to that of D-P concentration. 20 refs., 12 figs., 3 tabs.

  4. Economical effect of introducing a photovoltaic system on future electric power system; Shorai no denryoku keito eno taiyoko hatsuden system donyu ni yoru keizaiteki eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Akata, N.; Kenmoku, Y.; Sakakibara, T. [Toyohashi University of Technology, Aichi (Japan); Kawamoto, T. [Shizuoka University, Shizuoka (Japan); Nakagawa, S. [Maizuru National College of Technology, Kyoto (Japan)

    1997-11-25

    Economic impact of introduction in the future of photovoltaic power generation (PV) systems into the commercial power system is discussed from the electric utilities` point of view. In the discussion, future demand for power is predicted from the demand for power in the base year, and the optimum power source configuration corresponding to the future demand and power generation curve are worked out by use of linear programming. Then, the fixed cost and variable cost are calculated for each of the power source components, and then the expected reduction in cost per unit of power generated is calculated. As the power sources, the hydroelectric, pumped storage, oil-fired, coal-fired, LNG-fired, combined cycle, and atomic technologies are considered. The conclusion is stated below. Upon introduction of PV power equivalent to 10% of the maximum demand power, the maximum power in the service area of Chubu Electric Power Co., Inc., will be reduced by 1.23GW in 2025, and the yearly demand power by 5472GWh. Since PV lowers the peak, an increased number of power sources low in variable cost will be used although such will be low in tracking capability. An increase in power demand will enhance the cost reducing effect of the PV system. 5 refs., 4 figs., 3 tabs.

  5. Effects of silicon contents on formation of abnormal structures of aluminum alloy die castings; Aruminiumu gokin daikasuto no ijo soshiki keisei ni oyobosu keisoryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Komazaki, T.; Maruyama, Y.; Nishi, N. [Ryobi Ltd., Hiroshima (Japan)

    1995-04-25

    In this study, Al-5-11mass%Si binary alloys and commercial alloys with equivalent amount of silicon contents (AC2A, ADC10, ADC12) were fabricated into die castings with changed shot-time-lag, and effects of alloy structures on formation of abnormal structures were investigated. The results show the following discoveries. With the increasing of silicon contents in Al-Si binary alloys from 5 mass% to 11 mass%, the abnormal structures caused by the cooling and solidification of the molten metal in the injection sleeve will change from mainly coarse {alpha} phase to mainly breaking chill crystals as the solidification state is changing form porridge state to solid surface forming state. The abnormal structure of the commercial alloy AC2A mainly consists of coarse {alpha} phases and that of ADC12 mainly consists of breaking chill crystals. The ADC10 alloy is an intermediate alloy between them. The amount of dispersion for values of tensile strength of ADC12 alloy is larger than that of AC2A and ADC10 alloys because ADC12 alloy contains many breaking chill crystals. 12 refs., 11 figs., 4 tabs.

  6. Effect of synthetic detergent and soap on the waste-water treatment. Gosei senzai oyobi sekken no haisui shori ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Inamori, Y. (national Institute for Environmental Studies, Tsukuba (Japan)); Takamatsu, Y. (University of Tsukuba, Tsukuba (Japan))

    1993-05-01

    This paper describes the effect of surfactants on purification capability and living life phases in the living life membrane method and the activated sludge method as biological waste water treatment methods. As a result of treating artificial waste water in an immersion hearth process of the living life membrane method, it was found that LAS added concentration at 50 mg/l or higher would not affect noticeably the quality of water treated under a steady-state operation, but that at 100 mg/l has aggravated the treated water quality by increasing COD. In the case of soaps, the COD in the treated water has aggravated when the added concentration is 70 mg/l or higher. The result of discussing the activated sludge process using urban sewage water indicated that COD in the treated water shows higher value for synthetic detergents than for soaps at the detergent added concentration of 140 mg/l or higher, having affected adversely the treated water quality. An activated sludge treatment process was operated to identify the effects of synthetic detergents and soaps on living life phases in the activated sludge and living life membranes. The result suggests that either the LAS added system or the soap added system presents no problems in a long-time aeration, while activated sludge aerated for the standard period of time has a possibility of abnormally proliferating filamentous microorganisms that can cause bulking in the soap system. 14 refs., 3 tabs.

  7. Simulation modeling of fluidized bed coal gasifier for new topping cycle system; Ryushi jutenso no bunri seino ni oyobosu ryushi juten kozo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sakaguchi, H.; Adachi, K.; Ishiki, Y.; Fukui, K.; Ma, J.; Chi Yun, M. Shinoda, E.; Yoshida, H. [Hiroshima Univ., Higashi-Hiroshima (Japan). Faculty of Engineering

    1998-01-01

    A new topping cycle coal power generation process has been developed as a Japanese national project for a high efficiency power generation process. This process consists of a pressurized bubbling fluidized-bed coal gasifier and a pressurized bubbling fluidized-bed combustor which combined in series. To evaluate the performance and to determine specification and operation parameters of this process, it is extremely important to analyze the behavior and the performance of the system by a reasonable simulation model. A simulation model of this new process is developed in this paper. It is demonstrated by calculating results from this model that the carbon conversion in the gasifier, the composition and the heating value of the produced gas are strongly dependent on operating conditions. Heat recovery by steam in the combustor is controlled by the coal feed rate. 7 refs., 9 figs.

  8. Effects rearing conditions on the ambicoloration by young Japanese flounder; Hirame chigyo no mugen sokukokuka ni taisuru shiiku kankyo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, N.; Kikuchi, K.; Furuta, T. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1995-06-01

    Investigations were carried out on effects of rearing environments such as light and bottom conditions on the ambicoloration of Japanese flounder. Young flounders were reared for 4 to 16 weeks in a water tank whose lid and bottom are made of colorless transparent plastic plates. Intensities of fluorescent lamps installed above and below the water tank were controlled. Sand and black resin plates were laid on the bottom of the rearing tank to discuss effects from change in the bottom properties. When the bottom of the rearing tank is made of a transparent plastic plate, ambicoloration has occurred to the flounders even if lights were irradiated from below at intensities of 1100 Lux and 7 Lux or even if the lights were cut off by a black resin plate. Even under a condition that a sandpaper is laid on the bottom to give fish feeling like contacting sand, the ambicoloration has progressed. When sandy transparent glass powder is scattered on the bottom, generation factor of individuals with ambicoloration has reduced to about a quarter. These results revealed that existence of a sandy material into which flounders can hide themselves is important for the effect on the ambicoloration of flounder, rather than existence of light irradiation or stimulation given something like sand. 18 refs., 4 figs., 5 tabs.

  9. Effect of PV module output power on module temperature; Taiyo denchi no shutsuryoku henka ga module hyomen ondo ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Hongo, T.; Kitamura, A. [Kansai Electric Power Co. Inc., Osaka (Japan); Igaki, K.; Mizumoto, T. [Kanden Kako Co. Inc., Osaka (Japan)

    1996-10-27

    Effect of the photovoltaic (PV) module output power variation on the module surface temperature has been investigated by field measurements. PV modules with capacity of 54 W were used for the temperature measurements. Three 2 kW-class PV systems were operated. T-type thermocouples were used for measuring temperatures. Measurement time intervals were 15 minutes, 30 minutes, 60 minutes, and 24 hours. Measurement period was between May 25, 1995 and June 25, 1996. The surface temperature increased during non-loaded PV output, and decreased during load-carrying PV output. Difference of the surface temperature between non-loaded PV output and load-carrying PV output was 3.5{degree}C at maximum through a year. The surface temperature was saturated within 30 minutes. When PV output was changed in 30 or 60 minutes interval, the variation of surface temperature was distinctly observed. When PV output was changed in 15 minutes interval, it was not observed distinctly. There was no difference of the surface temperatures during the time zones with less solar radiation, such as in the morning and evening, and at night. Except these time zones, difference of the surface temperatures was 3.5{degree}C at maximum. 4 figs.

  10. Preparation and physical properties of CuxWO3

    Science.gov (United States)

    Koriche, N.; Bessekhouad, Y.; Bouguelia, A.; Trari, M.

    2012-04-01

    We report on the study of WO3 doped with Cu using sol-gel (CuxWO3d) and impregnation (CuxWO3i) methods. All materials are well crystallized and exhibit single phases whose crystallite size ranges from 17 to 100 nm depending on Cu amount and the preparation technique. The conductivity dependence on temperature demonstrates semiconductor behavior and follows the Arrhenius model, with activation energies, Eσ, commonly in the range 0.4-0.6 eV. Moreover, the thermopower study shows that CuxWO3d is mainly of p-type conductivity, whereas CuxWO3i is n-type. The mechanism of conduction is attributed to a small polaron hopping. The doping process is found to decrease the interband transition down to 520 nm depending on the preparation conditions. The photoelectrochemical characterization confirms the conductivity type and demonstrates that the photocurrent Jph increases with Cu-doping. Taking into consideration the activation energy, the flat band potential and the band gap energy, the band positions of each material are proposed according to the preparation method and Cu amount.

  11. Absolute activity determination of CaWO{sub 4} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Muenster, Andrea; Ertl, Andreas; Guetlein, Achim; Lanfranchi, Jean-Come; Potzel, Walter; Roth, Sabine; Simon, Daniel; Scholl, Stephan; Sivers, Moritz von; Strauss, Raimund; Wawoczny, Stephan; Willers, Michael; Wuestrich, Marc; Zoeller, Andreas [TU Muenchen, Fakultaet fuer Physik, E15, Garching (Germany)

    2013-07-01

    The direct Dark Matter search experiment CRESST uses CaWO{sub 4} single crystals as targets for possible WIMP recoils. A particle interaction in the crystal produces phonons as well as scintillation light. As the light signal is dependent on the kind of interacting particle, a particle discrimination on an event-by-event basis is feasible. The observed background is mainly due to intrinsic radioactive impurities of the CaWO{sub 4} target. An activity of this intrinsic contamination can be determined with the investigation of α-decays in the crystal. Up to now, CaWO{sub 4} crystals were produced by suppliers in Russia and Ukraine. Since 2011 we are able to grow CaWO{sub 4} crystals in a Czochralski furnace installed in the crystal laboratory of TU Munich, which has the advantage to better meet the requirements of CRESST and to ensure the availability of CaWO{sub 4} crystals for the successive future multi-material experiment EURECA. To check the radiopurity, first self-grown crystals were investigated in test measurements. In this talk we will present the results for absolute α-activities of self-grown crystals and compare them to α-activities of the crystals installed in the last CRESST run (Run32).

  12. Hydrothermal synthesis and chromic properties of hexagonal WO3 nanowires

    Institute of Scientific and Technical Information of China (English)

    Yuan Hua-Jun; Chen Ya-Qi; Yu Fang; Peng Yue-Hua; He Xiong-Wu; Zhao Ding; Tang Dong-Sheng

    2011-01-01

    This paper reports that highly purified hexagonal WO3 nanowires are synthesized by a simple hydrothermal method. The as-synthesized WO3 nanowires are investigated in detail by ultraviolet-visible-near infrared spectroscopy and electrical transport measurements under different conditions. It finds that the optical band gap and the diffuse reflection coefficient in the wavelength region above 450 nm of WO3 nanowires decrease observably upon exposure to ultraviolet light or NH3 gas. It is also found that there are electrons being trapped or released in individual WO3 nanowires when scanning bias voltage in different directions upon exposure to ultraviolet and NH3 gas. The experimental results suggest that the chromic properties might be attributed to the injection/extraction of hydrogen ions induced by ultraviolet light irradiation in air or creation/annihilation of oxygen vacancies induced by NH3 gas exposure, which serve as colour centres and trap electrons as polarons. The experimental results also suggest that the hexagonal WO3 nanowires will be a good candidate for sensing reduced gas such as NH3.

  13. Radioactive contamination of ZnWO4 crystal scintillators

    CERN Document Server

    Belli, P; Cappella, F; Cerulli, R; Danevich, F A; Dubovik, A M; d'Angelo, S; Galashov, E N; Grinyov, B V; Incicchitti, A; Kobychev, V V; Laubenstein, M; Nagornaya, L L; Nozzoli, F; Poda, D V; Podviyanuk, R B; Polischuk, O G; Prosperi, D; Shlegel, V N; Tretyak, V I; Tupitsyna, I A; Vasiliev, Ya V; Vostretsov, Yu Ya

    2010-01-01

    The radioactive contamination of ZnWO4 crystal scintillators has been measured deep underground at the Gran Sasso National Laboratory (LNGS) of the INFN in Italy with a total exposure 3197 kg x h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO4 samples. One of the ZnWO4 crystals has also been tested by ultra-low background gamma spectrometry. The radioactive contaminations of the ZnWO4 samples do not exceed 0.002 – 0.8 mBq/kg (depending on the radionuclide), the total alpha activity is in the range: 0.2 - 2 mBq/kg. Particular radioactivity, beta active 65Zn and alpha active 180W, has been detected. The effect of the re-crystallization on the radiopurity of the ZnWO4 crystal has been studied. The radioactive contamination of samples of the ceramic details of the set-ups used in the crystals growth has been checked by low background gamma spectrometry. A project scheme on further improvement of the radiopur...

  14. Photocatalytic activity of Bi2WO6/Bi2S3 heterojunctions: the facilitation of exposed facets of Bi2WO6 substrate

    Science.gov (United States)

    Yan, Long; Wang, Yufei; Shen, Huidong; Zhang, Yu; Li, Jian; Wang, Danjun

    2017-01-01

    Bi2S3/Bi2WO6 hybrid architectures with exposed (020) Bi2WO6 facets have been synthesized via a controlled anion exchange approach. X-ray photoelectron spectroscopy (XPS) reveals that a small amount of Bi2S3 was formed on the surface of Bi2WO6 during the anion exchange process, thus leading to the transformation from the Bi2WO6 to Bi2S3/Bi2WO6. A rhodamine B (RhB) aqueous solution was chosen as model organic pollutants to evaluate the photocatalytic activities of the Bi2S3/Bi2WO6 catalysts. Under visible light irradiation, the Bi2S3/Bi2WO6-TAA displayed the excellent visible light photoactivities compared with pure Bi2S3, Bi2WO6 and other composite photocatalysts. The efficient photocatalytic activity of the Bi2S3/Bi2WO6-TAA composite microspheres was ascribed to the constructed heterojunctions and the inner electric field caused by the exposed (020) Bi2WO6 facets. Active species trapping experiments revealed that h+ and O2rad - are the main active species in the photocatalytic process. Furthermore, the as-obtained photocatalysts showed good photocatalytic activity after four recycles. The results presented in this study provide a new concept for the rational design and development of highly efficient photocatalysts.

  15. On the nature of WO stars: a quantitative analysis of the WO3 star DR1 in IC 1613

    CERN Document Server

    Tramper, F; Hartoog, O E; Sana, H; de Koter, A; Vink, J S; Ellerbroek, L E; Langer, N; Garcia, M; Kaper, L; de Mink, S E

    2013-01-01

    Context. Oxygen sequence Wolf-Rayet (WO) stars are thought to represent the final evolutionary stage of the most massive stars. The characteristic strong O vi emission possibly originates from an enhanced oxygen abundance in the stellar wind. Alternatively, the O vi emission can be caused by the high temperature of these stars, in which case the WO stars are the high-temperature extension of the more common carbon sequence Wolf-Rayet (WC) stars. Aims. By constraining the physical properties and evolutionary status of DR1, a WO star in the low-metallicity Local Group dwarf galaxy IC 1613 and one of only two objects of its class known in a SMC-like metallicity environment, we aim to investigate the nature of WO stars and their evolutionary connection with WC stars. Methods. We use the non-LTE atmosphere code cmfgen to model the observed spectrum of DR1 and to derive its stellar and wind parameters. We compare our values with other studies of WC and WO stars, as well as with the predictions of evolutionary model...

  16. The chemistry of ZnWO4 nanoparticle formation

    DEFF Research Database (Denmark)

    Bøjesen, Espen Drath; Jensen, Kirsten Marie Ørnsbjerg; Tyrsted, Christoffer

    2016-01-01

    The need for a change away from classical nucleation and growth models for the description of nanoparticle formation is highlighted. By the use of in situ total X-ray scattering experiments the transformation of an aqueous polyoxometalate precursor mixture to crystalline ZnWO4 nanoparticles under...... hydrothermal conditions was followed. The precursor solution is shown to consist of specific Tourné-type sandwich complexes. The formation of pristine ZnWO4 within seconds is understood on the basis of local restructuring and three-dimensional reordering preceding the emergence of long range order in ZnWO4...... nanoparticles. An observed temperature dependent trend in defect concentration can be rationalized based on the proposed formation mechanism. Following nucleation the individual crystallites were found to grow into prolate morphology with elongation along the unit cell c-direction. Extensive electron microscopy...

  17. Degradation of methylene blue using porous WO3, SiO2-WO3, and their Au-loaded analogs: adsorption and photocatalytic studies.

    Science.gov (United States)

    DePuccio, Daniel P; Botella, Pablo; O'Rourke, Bruce; Landry, Christopher C

    2015-01-28

    A facile sonochemical approach was used to deposit 3-5 nm monodisperse gold nanoparticles on porous SiO2-WO3 composite spheres, as confirmed by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). High-resolution TEM (HR-TEM) and energy dispersive X-ray spectroscopy (EDS) further characterized the supported Au nanoparticles within the Au-SiO2-WO3 composite. These analyses showed isolated Au nanoparticles within both SiO2- and WO3-containing regions. Selective etching of the SiO2 matrix from Au-SiO2-WO3 yielded a pure Au-WO3 material with well-dispersed 10 nm Au nanoparticles and moderate porosity. This combined sonochemical-nanocasting technique has not been previously used to synthesize Au-WO3 photocatalysts. Methylene blue (MB) served as a probe for the adsorption capacity and visible light photocatalytic activity of these WO3-containing catalysts. Extensive MB demethylation (azures A, B, C, and thionine) and polymerization of these products occurred over WO3 under dark conditions, as confirmed by electrospray ionization mass spectrometry (ESI-MS). Photoirradiation of these suspensions led to further degradation primarily through demethylation and polymerization pathways, regardless of the presence of Au nanoparticles. Ring-opening sulfur oxidation to the sulfone was a secondary photocatalytic pathway. According to UV-vis spectroscopy, pure WO3 materials showed superior MB adsorption compared to SiO2-WO3 composites. Compared to their respective nonloaded catalysts, Au-SiO2-WO3 and Au-WO3 catalysts exhibited enhanced visible light photocatalytic activity toward the degradation of MB. Specifically, the rates of MB degradation over Au-WO3 and Au-SiO2-WO3 during 300 min of irradiation were faster than those over their nonloaded counterparts (WO3 and SiO2-WO3). These studies highlight the ability of Au-WO3 to serve as an excellent adsorbant and photodegradation catalyst toward MB.

  18. Intrinsic Defects and H Doping in WO3

    Science.gov (United States)

    Zhu, Jiajie; Vasilopoulou, Maria; Davazoglou, Dimitris; Kennou, Stella; Chroneos, Alexander; Schwingenschlögl, Udo

    2017-01-01

    WO3 is widely used as industrial catalyst. Intrinsic and/or extrinsic defects can tune the electronic properties and extend applications to gas sensors and optoelectonics. However, H doping is a challenge to WO3, the relevant mechanisms being hardly understood. In this context, we investigate intrinsic defects and H doping by density functional theory and experiments. Formation energies are calculated to determine the lowest energy defect states. O vacancies turn out to be stable in O-poor environment, in agreement with X-ray photoelectron spectroscopy, and O-H bond formation of H interstitial defects is predicted and confirmed by Fourier transform infrared spectroscopy. PMID:28098210

  19. Intrinsic Defects and H Doping in WO3

    KAUST Repository

    Zhu, Jiajie

    2017-01-18

    WO3 is widely used as industrial catalyst. Intrinsic and/or extrinsic defects can tune the electronic properties and extend applications to gas sensors and optoelectonics. However, H doping is a challenge to WO3, the relevant mechanisms being hardly understood. In this context, we investigate intrinsic defects and H doping by density functional theory and experiments. Formation energies are calculated to determine the lowest energy defect states. O vacancies turn out to be stable in O-poor environment, in agreement with X-ray photoelectron spectroscopy, and O-H bond formation of H interstitial defects is predicted and confirmed by Fourier transform infrared spectroscopy.

  20. Intrinsic Defects and H Doping in WO3

    Science.gov (United States)

    Zhu, Jiajie; Vasilopoulou, Maria; Davazoglou, Dimitris; Kennou, Stella; Chroneos, Alexander; Schwingenschlögl, Udo

    2017-01-01

    WO3 is widely used as industrial catalyst. Intrinsic and/or extrinsic defects can tune the electronic properties and extend applications to gas sensors and optoelectonics. However, H doping is a challenge to WO3, the relevant mechanisms being hardly understood. In this context, we investigate intrinsic defects and H doping by density functional theory and experiments. Formation energies are calculated to determine the lowest energy defect states. O vacancies turn out to be stable in O-poor environment, in agreement with X-ray photoelectron spectroscopy, and O-H bond formation of H interstitial defects is predicted and confirmed by Fourier transform infrared spectroscopy.

  1. Facile Hydrogen Evolution Reaction on WO3Nanorods

    Directory of Open Access Journals (Sweden)

    Rajeswari Janarthanan

    2007-01-01

    Full Text Available AbstractTungsten trioxide nanorods have been generated by the thermal decomposition (450 °C of tetrabutylammonium decatungstate. The synthesized tungsten trioxide (WO3 nanorods have been characterized by XRD, Raman, SEM, TEM, HRTEM and cyclic voltammetry. High resolution transmission electron microscopy and X-ray diffraction analysis showed that the synthesized WO3nanorods are crystalline in nature with monoclinic structure. The electrochemical experiments showed that they constitute a better electrocatalytic system for hydrogen evolution reaction in acid medium compared to their bulk counterpart.

  2. Synthesis of Shape-Tailored WO3 Micro-/Nanocrystals and the Photocatalytic Activity of WO3/TiO2 Composites

    Directory of Open Access Journals (Sweden)

    István Székely

    2016-03-01

    Full Text Available A traditional semiconductor (WO3 was synthesized from different precursors via hydrothermal crystallization targeting the achievement of three different crystal shapes (nanoplates, nanorods and nanostars. The obtained WO3 microcrystals were analyzed by the means of X-ray diffraction (XRD, scanning electron microscopy (SEM and diffuse reflectance spectroscopy (DRS. These methods contributed to the detailed analysis of the crystal morphology and structural features. The synthesized bare WO3 photocatalysts were totally inactive, while the P25/WO3 composites were efficient under UV light radiation. Furthermore, the maximum achieved activity was even higher than the bare P25’s photocatalytic performance. A correlation was established between the shape of the WO3 crystallites and the observed photocatalytic activity registered during the degradation of different substrates by using P25/WO3 composites.

  3. Comparing WO$(\\omega^\\omega)$ with $\\Sigma^0_2$ induction

    OpenAIRE

    Simpson, Stephen G.

    2015-01-01

    Let WO$(\\omega^\\omega)$ be the statement that the ordinal number $\\omega^\\omega$ is well ordered. WO$(\\omega^\\omega)$ has occurred several times in the reverse-mathematical literature. The purpose of this expository note is to discuss the place of WO$(\\omega^\\omega)$ within the standard hierarchy of subsystems of second-order arithmetic. We prove that WO$(\\omega^\\omega)$ is implied by I$\\Sigma^0_2$ and independent of B$\\Sigma^0_2$. We also prove that WO$(\\omega^\\omega)$ and B$\\Sigma^0_2$ toge...

  4. Reactive Sputter Deposition of WO3/Ag/WO3 Film for Indium Tin Oxide (ITO)-Free Electrochromic Devices.

    Science.gov (United States)

    Yin, Yi; Lan, Changyong; Guo, Huayang; Li, Chun

    2016-02-17

    Functioning both as electrochromic (EC) and transparent-conductive (TC) coatings, WO3/Ag/WO3 (WAW) trilayer film shows promising potential application for ITO-free electrochromic devices. Reports on thermal-evaporated WAW films revealed that these bifunctional WAW films have distinct EC characteristics; however, their poor adhesive property leads to rapid degradation of coloring-bleaching cycling. Here, we show that WAW film with improved EC durability can be prepared by reactive sputtering using metal targets. We find that, by introducing an ultrathin tungsten (W) sacrificial layer before the deposition of external WO3, the oxidation of silver, which leads to film insulation and apparent optical haze, can be effectively avoided. We also find that the luminous transmittance and sheet resistance were sensitive to the thicknesses of tungsten and silver layers. The optimized structure for TC coating was obtained to be WO3 (45 nm)/Ag (10 nm)/W (2 nm)/WO3 (45 nm) with a sheet resistance of 16.3 Ω/□ and a luminous transmittance of 73.7%. Such film exhibits compelling EC performance with decent luminous transmittance modulation ΔTlum of 29.5%, fast switching time (6.6 s for coloring and 15.9 s for bleaching time), and long-term cycling stability (2000 cycles) with an applied potential of ±1.2 V. Thicker external WO3 layer (45/10/2/100 nm) leads to larger modulation with maximum ΔTlum of 46.4%, but at the cost of significantly increasing the sheet resistance. The strategy of introducing ultrathin metal sacrificial layer to avoid silver oxidation could be extended to fabricating other oxide-Ag-oxide transparent electrodes via low-cost reactive sputtering.

  5. Examining the Gas Sensing Properties of the Nanocrystalline Sm2O3-WO3

    Institute of Scientific and Technical Information of China (English)

    邓粲达; 林冠男; 林鸿明; 杨宗烨

    2004-01-01

    In this study, nanocrystalline (NC) WO3 and Sm2O3-WO3 gas sensors have been synthesized and deposited on Al2O3 substrate by gas condensation method, then sintering to 600℃. SEM is used to observe the morphology of the surface. TEM is used to measure the particle size. The resistance of sensor is measured in different temperatures and gas concentration to evaluate the sensing properties of NC WO3 and NC Sm2O3-WO3 sensor. The results indicate that WO3 is a usability gas sensor material. After Sm2O3 is doped in WO3, it does not obviously influence CO detection; it owns better sensitivity and stability. To UV irradiation on WO3, the sensitivity of WO3 is enhanced and it maintains WO3 recovery properties in NO2 detecting. UV irradiation on Sm2O3 doped WO3 does not show enhanced well properties as UV illuminate on WO3.

  6. 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.

  7. Tunable luminescence and enhanced photocatalytic activity for Eu(III) doped Bi2WO6 nanoparticles.

    Science.gov (United States)

    Gu, Haidong; Yu, Lei; Wang, Juan; Ni, Min; Liu, Tingting; Chen, Feng

    2017-04-15

    A series of Eu(III) doped Bi2WO6 nanoparticles were synthesized by a hydrothermal process. The obtained Bi2WO6:Eu(III) nanoparticles were characterized by XRD, SEM, luminescence spectrophotometer and DRS. The XRD and TEM results indicate that the Eu(III) doping concentration has no influence on the phase and morphology. However, the Eu(III) doping can tune the luminescence and enhance the photocatalytic activity of Bi2WO6. With the increases of Eu(3+) doping concentrations, the emission intensity of WO6(6-) group decreases nut the photocatalytic activity increases. The tunable luminescence of Bi2WO6:Eu(III) nanoparticles results from the energy transfer from WO6(6-) group to Eu(III) ion. The enhanced performance can be ascribed to efficient separation of electron and hole pairs after doping Eu(III) into the Bi2WO6 lattice.

  8. Charged particle response of PbWO4

    NARCIS (Netherlands)

    Hoek, M; Doring, W; Hejny, [No Value; Lohner, H; Metag, [No Value; Novotny, R; Wortche, H

    2002-01-01

    The response of PbWO4 to high-energy protons has been investigated in two test experiments at the proton facilities Cosy and AGOR. The determined energy resolution below 360 MeV of sigma/E = 1.44%/E-gamma(1/2) + 1.97% is comparable to the known photon response. Measured spectra of inelastically

  9. Charged particle detection with PbWO4

    NARCIS (Netherlands)

    Hoek, M; Doring, W; Hejny, [No Value; Lohner, H; Metag, [No Value; Novotny, R; Wortche, H

    The response of PbWO4 to high-energy protons has been investigated in two test experiments at the proton beam facilities COSY and AGOR. The determined energy resolution below 360 MeV of sigma/E = 0.97%/E-gamma(1/2) + 3.33% is comparable to the previously deduced photon response. Energy spectra of

  10. Enhanced photocatalytic properties in well-ordered mesoporous WO3

    KAUST Repository

    Li, Li

    2010-01-01

    We used polyisoprene-block-ethyleneoxide copolymers as structure-directing agents to synthesise well-ordered and highly-crystalline mesoporous WO 3 architectures that possess improved photocatalytic properties due to enhanced dye-adsorption in absence of diffusion limitation. © 2010 The Royal Society of Chemistry.

  11. Sintering temperature and impedance analysis of Mn{sub 0.9}Co{sub 1.2}Ni{sub 0.27}Mg{sub 0.15}Al{sub 0.03}Fe{sub 0.45}O{sub 4} NTC ceramic prepared by W/O microemulsion method

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Junbo [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, Qing, E-mail: zhaoq@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); Gao, Bo [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); Chang, Aimin, E-mail: changam@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); Zhang, Bo; Zhao, Pengjun; Ma, Renjun [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2014-12-25

    Highlights: • The ceramics are mainly in spinel phase and cubic cobalt oxide phase. • A perfect sintering temperature of 1450 °C for the Mn–Co–Ni–Mg–Al–Fe–O was proposed. • The NTC characteristic of the ceramics derive from grain boundary resistance R{sub gb}. - Abstract: The Mn{sub 0.9}Co{sub 1.2}Ni{sub 0.27}Mg{sub 0.5}Al{sub 0.03}Fe{sub 0.45}O{sub 4} negative temperature coefficient (NTC) ceramics derived from nano-particles were sintered at 1380 °C, 1450 °C and 1560 °C, respectively. X-ray diffraction (XRD) result showed that the ceramics sintered at 1380 °C and 1450 °C were mainly in the cubic spinel structure except for a little of tetragonal spinel, and that sintered at 1560 °C was consisted of cubic spinel and cubic cobalt oxide phase. Scanning electron microscopy (SEM) image indicated that the grain size of the ceramic increased sharply when the sintering temperature increased from 1380 °C to 1450 °C, and it changed little when the temperature further increased to 1560 °C, while the porosity was enlarged seriously. Thus a perfect sintering temperature of 1450 °C was proposed. Impedance analysis revealed that the grain resistance R{sub g} showed positive temperature coefficient thermistor characteristic, while the grain boundary resistance R{sub gb} possessed negative temperature coefficient characteristic. Because the grain boundary resistance R{sub gb} was two orders of magnitude larger than the grain resistance R{sub g}, the material thus showed negative temperature coefficient thermistor characteristic.

  12. Electroless deposition of NiWB alloy on p-type Si(1 0 0) for NiSi contact metallization

    Energy Technology Data Exchange (ETDEWEB)

    Duhin, A. [Department of Physical Electronics, Engineer Faculty, Tel-Aviv University, Ramat-Aviv 69978 (Israel)], E-mail: alla.douhin@gmail.com; Sverdlov, Y. [Department of Physical Electronics, Engineer Faculty, Tel-Aviv University, Ramat-Aviv 69978 (Israel); Feldman, Y. [Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100 (Israel); Shacham-Diamand, Y. [Department of Physical Electronics, Engineer Faculty, Tel-Aviv University, Ramat-Aviv 69978 (Israel)

    2009-10-30

    Recently, we have proposed a novel method to form NiSi contacts using electroless plating of Ni-alloys (NiP, NiWP, NiWB) on p-type Si(1 0 0) modified by aminopropyltriethoxysilane (APTS) activated with Pd-citrate [A. Duhin, Y. Sverdlov, Yishay Feldman, Y. Shacham-Diamand, Microelectron. Eng. 84 (2007) 2506]. In this work we focus on NiWB thin films that were formed by this method. Alkali metal free electroless plating was developed using dimethylamine-borane (DMAB) and tungstatic acid (H{sub 2}WO{sub 4}) as a reducing agent and a source of tungsten ions, respectively. Using this method we succeeded to receive relatively high tungsten concentration (maximum value of 19-21 at%) in the electroless deposited NiWB films with good adhesion to the Si-substrate. In this paper, the advantages of using the APTS activated with Pd-citrate for NiWB alloy deposition on the Si substrate is discussed. The chemically deposited NiWB samples were annealed for 1-2 h in vacuum (<10{sup -6} Torr) forming the silicide layer. The annealing temperatures were 650 deg. C for NiWB alloys. X-ray diffraction (XRD) measurement confirmed the presence of NiSi phase after annealing. In addition the WSi{sub 2} phase was formed. The results are reported and summarized.

  13. Electrodeposition, characterization and long term stability of NiW and NiWZn coatings on copper substrate in alkaline solution

    Science.gov (United States)

    Sürme, Yavuz; Gürten, A. Ali; Kayakırılmaz, Kadriye

    2013-07-01

    This paper describes the electrodeposition of Ni, NiW and NiWZn coatings onto copper surfaces from electrolyte solutions containing Na3C6H5O7, Na2WO4, NiSO4 and ZnSO4. The electrocatalytic effects of electrodeposited coatings were investigated for hydrogen evolution reactions in 1 M NaOH solution. Surface characterization studies were carried out by energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy and cross-section analysis. The effect of operating conditions on the chemical composition, microstructure and electrocatalytic properties of Ni-W coatings was studied. The Zn ions were used to improve the active surface area and catalytic activity of the electrodeposited surface. The electrocatalytic activity of NiW and NiWZn coated electrodes for the hydrogen evolution reaction in alkaline solution was compared with that of an electrodeposited Ni electrode and copper substrate by using cathodic polarization curves and electrochemical impedance spectroscopy techniques over 96 h of electrolysis. The results proved that the NiWZn coated electrode showed better electrocatalytic activity and durability than bare Cu, Ni and NiW coatings.

  14. Tungsten-based nanomaterials (WO3 & Bi2WO6): Modifications related to charge carrier transfer mechanisms and photocatalytic applications

    Science.gov (United States)

    Girish Kumar, S.; Koteswara Rao, K. S. R.

    2015-11-01

    Heterogeneous photocatalysis is an ideal green energy technology for the purification of wastewater. Although titania dominates as the reference photocatalyst, its wide band gap is a bottleneck for extended utility. Thus, search for non-TiO2 based nanomaterials has become an active area of research in recent years. In this regard, visible light absorbing polycrystalline WO3 (2.4-2.8 eV) and Bi2WO6 (2.8 eV) with versatile structure-electronic properties has gained considerable interest to promote the photocatalytic reactions. These materials are also explored in selective functional group transformation in organic reactions, because of low reduction and oxidation potential of WO3 CB and Bi2WO6 VB, respectively. In this focused review, various strategies such as foreign ion doping, noble metal deposition and heterostructuring with other semiconductors designed for efficient photocatalysis is discussed. These modifications not only extend the optical response to longer wavelengths, but also prolong the life-time of the charge carriers and strengthen the photocatalyst stability. The changes in the surface-bulk properties and the charge carrier transfer dynamics associated with each modification correlating to the high activity are emphasized. The presence of oxidizing agents, surface modification with Cu2+ ions and synthesis of exposed facets to promote the degradation rate is highlighted. In depth study on these nanomaterials is likely to sustain interest in wastewater remediation and envisaged to signify in various green energy applications.

  15. Nano-WO3 film modified macro-porous silicon (MPS) gas sensor

    Institute of Scientific and Technical Information of China (English)

    Sun Peng; Hu Ming; Li Mingda; Ma Shuangyun

    2012-01-01

    We prepared macro-porous silicon (MPS) by electrochemical corrosion in a double-tank cell on the surface of single-crystalline P-type silicon.Then,nano-WO3 films were deposited on MPS layers by DC facing target reactive magnetron sputtering.The morphologies of the MPS and WOs/MPS samples were investigated by using a field emission scanning electron microscope.The crystallization of WO3 and the valence of the W in the WO3/MPS sample were characterized by X-ray diffraction and X-ray photoelectron spectroscopy,respectively.The gas sensing properties of MPS and WO3/MPS gas sensors were thoroughly measured at room temperature.It can be concluded that:the WO3/MPS gas sensor shows the gas sensing properties of a P-type semiconductor gas sensor.The WO3/MPS gas sensor exhibits good recovery characteristics and repeatability to l ppm NO2.The addition of WO3 can enhance the sensitivity of MPS to NO2.The long-term stability ofa WO3/MPS gas sensor is better than that of an MPS gas sensor.The sensitivity of the WO3/MPS gas sensor to NO2 is higher than that to NH3 and C2H5OH.The selectivity of the MPS to NO2 is modified by deposited nano-WO3 film.

  16. Synthesis of surface sulfated BiWO with enhanced photocatalytic performance

    Institute of Scientific and Technical Information of China (English)

    Yongming Ju; Jianming Hong; Xiuyu Zhang; Zhencheng Xu; Dongyang Wei; Yanhong Sang; Xiaohang Fang; Jiande Fang; Zhenxing Wang

    2012-01-01

    Sulfated BiWO (SBiWO) was synthesized by an impregnation method to enhance the visible-light-driven photoactivities of BiWO (BiWO).The characterization results verified that sulfate anion mainly anchored on the catalyst surface greatly extended the visible-light-responsive range without destroying the crystal lattice.Moreover,the SBiWO-based photoactivities were evaluated with the removal of Malachite Green (MG) under UV-Vis irradiation emitted from two microwave-powered electrodeless discharge lamps (MPEDL-2) and under visible light (λ > 420 nm).The results demonstrated that the kinetic constant was increased 2.25 times,varying from 0.1478 (BiWO) to 0.3328 min-1 (SBiWO-1).Similar results were also obtained for the visible light-driven reaction.Furthermore,radical scavengers such as t-butanol restricted the visible-light induced degradation of MG over BiWO and SBiWO-1.This indicated that the sulfating process increased the generation of reactive oxygen species,which was further verified by molecular probe with salicylic acid.Thus,more blue-shifting at λ =618 nm was observed over SBiWO.On the basis of the above results,the photocatalytic mechanism over the sulfated catalyst was also discussed.

  17. Photocatalysis of WO3 Nanoplates Synthesized by Conventional-Hydrothermal and Microwave-Hydrothermal Methods and of Commercial WO3 Nanorods

    Directory of Open Access Journals (Sweden)

    Jarupat Sungpanich

    2014-01-01

    Full Text Available The degradation of methylene blue (MB dye by tungsten oxide (WO3 photocatalyst synthesized by the 200°C conventional-hydrothermal (C-H and 270 W microwave-hydrothermal (M-H methods and commercial WO3 was studied under UV light irradiation for 360 min. The photocatalysts were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, Fourier transform infrared (FTIR spectroscopy, Raman spectrophotometry, and UV visible spectroscopy to determine phase, morphology, vibration mode, and optical property. The BET analysis revealed the specific surface area of 29.74, 37.25, and 33.56 m2/g for the C-H WO3 nanoplates, M-H WO3 nanoplates, and commercial WO3 nanorods, respectively. In this research, the M-H WO3 nanoplates have the highest photocatalytic efficiency of 90.07% within 360 min, comparing to the C-H WO3 nanoplates and even commercial WO3 nanorods.

  18. Facile synthesis of hierarchical double-shell WO3 microspheres with enhanced photocatalytic activity

    Science.gov (United States)

    Wang, Zhenfeng; Chu, Deqing; Wang, Limin; Wang, Lipeng; Hu, Wenhui; Chen, Xiangyu; Yang, Huifang; Sun, Jingjing

    2017-02-01

    Hierarchical double-shell WO3 microspheres (HDS-WO3) have been successfully obtained through the thermal decomposition of WO3·H2O formed by metal salts as the templates. The products were characterized by X-ray diffraction (XRD), and the morphology was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, the HDS-WO3 microspheres were analyzed by the Thermogravimetric (TG) and Brunauer-Emmett-Teller (BET) analysis. The synthetic mechanism of the products with hierarchical structures was proposed. The obtained HDS-WO3 exhibits excellent photocatalytic efficiency (84.9%), which is much higher than other WO3 sample under visible light illumination.

  19. Fungus mediated biosynthesis of WO3 nanoparticles using Fusarium solani extract

    Science.gov (United States)

    Kavitha, N. S.; Venkatesh, K. S.; Palani, N. S.; Ilangovan, R.

    2017-05-01

    Currently nanoparticles were synthesized by emphasis bioremediation process due to less hazardous, eco-friendly and imperative applications on biogenic process. Fungus mediated biosynthesis strategy has been developed to prepare tungsten oxide nanoflakes (WO3, NFs) using the plant pathogenic fungus F.solani. The powder XRD pattern revealed the monoclinic crystal structure with improved crystalline nature of the synthesized WO3 nanoparticles. FESEM images showed the flake-like morphology of WO3, with average thickness and length around 40 nm and 300 nm respectively. The Raman spectrum of WO3 NFs showed their characteristic vibration modes that revealed the defect free nature of the WO3 NFs. Further, the elemental analysis indicated the stoichiometric composition of WO3 phase.

  20. WO{sub 3} nanorods prepared by low-temperature seeded growth hydrothermal reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Chai Yan [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Abdul Razak, Khairunisak, E-mail: khairunisak@eng.usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); NanoBiotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lockman, Zainovia, E-mail: zainovia@eng.usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2014-03-05

    Highlights: • WO{sub 3} nanorods with 5–10 nm diameter were grown directly on seeded tungsten foil. • WO{sub 3} nanorods were successfully grown at low temperature of 80 °C. • WO{sub 3} nanorods were grown on the entire surface of the seed layer after 24 h. • Annealed nanorods showed better electrochromic properties than as-made nanorods. -- Abstract: This work describes the first tungsten oxide (WO{sub 3}) nanorods hydrothermally grown on W foil. WO{sub 3} nanorods were successfully grown at low hydrothermal temperature of 80 °C by seeded growth hydrothermal reaction. The seed layer was prepared by thermally oxidized the W foil at 400 °C for 0.5 h. This work discusses the effect of hydrothermal reaction and annealing period on the morphological, structural, and electrochromic properties of WO{sub 3} nanorods. Various hydrothermal reaction periods (8–24 h) were studied. Monoclinic WO{sub 3} nanorods with 5–10 nm diameter were obtained after hydrothermal reaction for 24 h. These 24 h WO{sub 3} nanorods were also annealed at 400 °C with varying dwelling periods (0.5–4 h). Electrochromic properties of WO{sub 3} nanorods in an acidic electrolyte were analyzed using cyclic voltammetry and UV–vis spectrophotometry. WO{sub 3} nanorods annealed at 400 °C for 1 h showed the highest charge capacity and the largest optical contrast among the 24 h WO{sub 3} films. The sample also showed good cycling stability without significant degradation. Based on the results, the reaction mechanism of WO{sub 3} nanorod formation on W foil was proposed.

  1. Obtaining of films of tungsten trioxide (WO3) by resistive heating of a tungsten filament

    OpenAIRE

    2008-01-01

    Thin film of tungsten oxide (WO3) has been studied extensively as an electrochromic material and has numerous applications in electrochromic devices, smart windows, gas sensors and optical windows. In order to explore the possibility of using it in electrochromic devices, thorough study the optical properties of the WO3 is an important step. The WO3 layers have been grown by hot-filament metal oxide deposition technique under atmospheric pressure and an oxygen atmosphere. By FTIR and Raman sc...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-08-15

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

  3. Fabrication of Pd Doped WO3 Nanofiber as Hydrogen Sensor

    Directory of Open Access Journals (Sweden)

    Alireza Nikfarjam

    2013-01-01

    Full Text Available Pd doped WO3 fibers were synthesized by electro-spinning. The sol gel method was employed to prepare peroxopolytungstic acid (P-PTA. Palladium chloride and Polyvinyl pyrrolidone (PVP was dissolved in the sol Pd:WO3 = 10% molar ratio. The prepared sol was loaded into a syringe connected to a high voltage of 18.3 kV and electrospun fibers were collected on the alumina substrates. Scanning electron microscope (SEM, X-ray powder diffraction (XRD and X-ray photoelectron spectroscopy (XPS techniques were used to analyze the crystal structure and chemical composition of the fibers after heat treatment at 500 °C. Resistance-sensing measurements exhibited a sensitivity of about 30 at 500 ppm hydrogen in air, and the response and recovery times were about 20 and 30 s, respectively, at 300 °C. Hydrogen gas sensing mechanism of the sensor was also studied.

  4. Surface oxygen vacancies on WO3 contributed to enhanced photothermo-synergistic effect

    Science.gov (United States)

    Li, Yingying; Wang, Changhua; Zheng, Han; Wan, Fangxu; Yu, Fei; Zhang, Xintong; Liu, Yichun

    2017-01-01

    Photothermooxidation has demonstrated a high efficiency in the removal of volatile organic compounds in air. Among photothermocatalysts, attention is presently focused on composites of noble metal/metal oxide or metal oxide/metal oxide. Instead, in this work, we present a case of single oxide WO3 subjected to hydrogen treatment as photothermocatalyst. With the increase of hydrogen treatment temperature, the color of WO3 changes from yellow to blue to dark blue and a phase transition from WO3 to WO2.72 to WO2 is accompanied, suggesting an increase of concentration of oxygen vacancy. Photothermocatalytic test against degradation of gaseous acetaldehyde at 60 °C under UV light shows that WO3-x sample with low concentration of oxygen vacancy displays the most significant synergetic effect between photocatalysis and thermocatalysis. Its photothermocatalytic activity in terms of CO2 evolution rate is 5.2 times higher than that of photocatalytic activity. However, WO3-WO2.72 and WO2 with high degree of oxygen deficiency show insignificant synergetic effect between photocatalysis and thermocatalysis. The reason for the different synergistic effect over above samples is believed to lie in balance between decreased activation energy of lattice oxygen and recombination of photogenerated electrons and holes induced by oxygen deficiency.

  5. Photocatalysis and photoinduced hydrophilicity of WO3 thin films with underlying Pt nanoparticles.

    Science.gov (United States)

    Miyauchi, Masahiro

    2008-11-07

    The photocatalytic oxidation and photoinduced hydrophilicity of thin tungsten trioxide (WO(3)) films coupled with platinum (Pt) nanoparticles were investigated. WO(3) films with underlying Pt nanoparticles (WO(3)/Pt/substrate) and those with overlying Pt nanoparticles (Pt/WO(3)/substrate) were synthesized by sputtering and sol-gel methods. Between these films, underlying Pt nanoparticles greatly enhanced the photocatalytic oxidation activity of WO(3) without decreasing the photoinduced hydrophilic conversion. However, overlying Pt nanoparticles deteriorated the hydrophilicity of WO(3) because the Pt nanoparticle surface was hydrophobic. The enhanced photocatalytic reaction by the Pt nanoparticles was attributed to the multi-electron reduction in Pt, which is caused by the injected electrons from the conduction band of WO(3). The relationship between photocatalytic activity and thin film structure, including the size of Pt nanoparticles, the thickness and porosity of the WO(3) layer, were investigated. Consequently, the optimum structure for high performance in both photocatalysis and photoinduced hydrophilicity was WO(3) (50 nm)/Pt(1.5 nm)/substrate, and this film exhibited a significant self-cleaning property even under visible light irradiation.

  6. Synthesis and photocatalytic properties of α-ZnWO4 nanocrystals in tungsten zinc borate glasses

    Directory of Open Access Journals (Sweden)

    Tatsuya Ida

    2014-09-01

    Full Text Available Tungsten oxide (WO3-containing glasses of WO3–ZnO–B2O3 were prepared using a conventional melt quenching method, and α-ZnWO4 nanocrystals were synthesized through the crystallization of glasses. A glass with the composition of 20WO3–50ZnO–30B2O3 showed the bulk crystallization of α-ZnWO4 nanocrystals with a diameter of ∼10 nm. Broad and asymmetric emission peaks were observed at the wavelength of λ ∼ 475 nm, i.e., blue emissions, in the photoluminescence spectra for the samples with α-ZnWO4 nanocrystals. From the degradation of the intensity of optical absorption under ultraviolet light (λ = 254 nm irradiations for the solution consisting of crystallized particles with α-ZnWO4 nanocrystals and methylene blue, it was clarified that α-ZnWO4 nanocrystals formed have photocatalytic activities. The formation of α-ZnWO4 nanocrystals is discussed from the viewpoint of the glass-forming tendency.

  7. Tailoring surface states in WO{sub 3} photoanodes for efficient photoelectrochemical water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Trilok; Müller, Ralf [Institute of Inorganic Chemistry, University of Cologne, Greinstrasse-6, D-50939 Cologne (Germany); Singh, Jai [Institute of Advanced Materials Engineering, Department of Nano Science and Technology, Sejong University, Seoul 143-747 (Korea, Republic of); Mathur, Sanjay, E-mail: sanjay.mathur@uni-koeln.de [Institute of Inorganic Chemistry, University of Cologne, Greinstrasse-6, D-50939 Cologne (Germany)

    2015-08-30

    Highlights: • WO{sub 3} thin films have been synthesized by reactive sputtering under oxygen atmosphere. • Surface treatment of WO{sub 3} influences the optical and photoelectrochemical properties. • Tailoring the surface properties by (i) hydrogen plasma treatment and (ii) anchoring plasmonic nanoparticles (Au and Ag) altered the light harvesting and charge separation/transport processes of WO{sub 3} photoanodes. - Abstract: The dynamics of photo-induced charge carriers are significantly influenced by the surface states of WO{sub 3} thin films, which were synthesized by reactive sputtering of tungsten substrates in oxygen plasma. Tailoring the surface properties by (i) hydrogen plasma treatment and (ii) anchoring plasmonic nanoparticles (Au and Ag) altered the light harvesting and charge separation/transport processes of WO{sub 3} photoanodes. Upon hydrogen plasma-treatment and coating of noble metal clusters, WO{sub 3} films showed enhanced visible light absorption and consequently higher photocurrent density (1.4 mA cm{sup −2}) compared to pristine WO{sub 3} (0.2 mA cm{sup −2}). Enhancement in hydrogen treated WO{sub 3} sample was found to be due to the reduction of W(VI) into W(V) centers, which produced substoichiometric WO{sub 3−x} phases, whereas noble metal particles contributed towards both resonant and non-resonant scattering of incident light thereby increasing photon-to-current conversion efficiency.

  8. Synthesis and ionic liquid gating of hexagonal WO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Phillip M., E-mail: philwu@stanford.edu, E-mail: beasley@stanford.edu; Munakata, Ko; Hammond, R. H.; Geballe, T. H.; Beasley, M. R., E-mail: philwu@stanford.edu, E-mail: beasley@stanford.edu [Department of Applied Physics, Stanford University, Stanford, California 94305, USA and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Ishii, Satoshi; Tanabe, Kenji; Tokiwa, Kazuyasu [Department of Applied Electronics, Tokyo University of Science, Katsushika-ku, Tokyo 125-8585 (Japan)

    2015-01-26

    Via thin film deposition techniques, the meta-stable in bulk crystal hexagonal phase of tungsten oxide (hex-WO{sub 3}) is stabilized as a thin film. The hex-WO{sub 3} structure is potentially promising for numerous applications and is related to the structure for superconducting compounds found in WO{sub 3}. Utilizing ionic liquid gating, carriers were electrostatically induced in the films and an insulator-to-metal transition is observed. These results show that ionic liquid gating is a viable technique to alter the electrical transport properties of WO{sub 3}.

  9. Eukaryotic association module in phage WO genomes from Wolbachia

    Science.gov (United States)

    Bordenstein, Sarah R.; Bordenstein, Seth R.

    2016-01-01

    Viruses are trifurcated into eukaryotic, archaeal and bacterial categories. This domain-specific ecology underscores why eukaryotic viruses typically co-opt eukaryotic genes and bacteriophages commonly harbour bacterial genes. However, the presence of bacteriophages in obligate intracellular bacteria of eukaryotes may promote DNA transfers between eukaryotes and bacteriophages. Here we report a metagenomic analysis of purified bacteriophage WO particles of Wolbachia and uncover a eukaryotic association module in the complete WO genome. It harbours predicted domains, such as the black widow latrotoxin C-terminal domain, that are uninterrupted in bacteriophage genomes, enriched with eukaryotic protease cleavage sites and combined with additional domains to forge one of the largest bacteriophage genes to date (14,256 bp). To the best of our knowledge, these eukaryotic-like domains have never before been reported in packaged bacteriophages and their phylogeny, distribution and sequence diversity imply lateral transfers between bacteriophage/prophage and animal genomes. Finally, the WO genome sequences and identification of attachment sites will potentially advance genetic manipulation of Wolbachia. PMID:27727237

  10. WO3 nanotubes prepared by a coaxial electrospinning method.

    Science.gov (United States)

    Cao, Xingxing; Zhang, Xuebin; Hu, Jixiang; Wang, Yang; Liu, Jia; Wu, Haijun; Feng, Yi

    2014-08-01

    In this paper, WO3 nanotubes were prepared by a coaxial electrospinning method. Firstly, core-shell structured composite fibers were fabricated via coaxial electrospinning under the optimal electro-spinning parameters to get the best composite fibers with uniform diameters and smooth surface, which pure PVA being the core solution and PVA/AMT/alcohol being the shell one, respectively. Secondly, the composite fibers were calcined in air at 600 °C for 4 h to wipe out the pure PVA, leading to the formation of nanotubes. After sintering, the obtained WO3 nanotubes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The XRD show that the resultant materials consist of pure tungsten trioxide (WO3) with good crystallinity, while FESEM and HRTEM images indicate that the materials are nanotubes with rough surface and consist of nanoparticles. The inner diameter and the wall thickness of nanotubes were calculated to be around 100 and 50 nm, respectively.

  11. Thermodynamic study of WO{sub 3} and WO{sub 3}:Li{sup +} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Avellaneda, Cesar O. [Laboratorio Interdisciplinar de Eletroquimica e Ceramica-LIEC, Departamento de Quimica, Universidade Federal de Sao Carlos, C.P. 676, CEP 13565-905 Sao Carlos, SP (Brazil)]. E-mail: avellane@dq.ufscar.br

    2007-03-25

    There is a considerable interest in the research and development of materials and devices that can be used for optical switching of large-scale glazings. Several potential switching technologies are available for glazings, including those based on electrochromic, thermochromic and photochromic phenomena. One of the most promising technologies for optical switching devices is the electrochromism (EC). In order to improve the electrochromic properties of tungsten oxide we have investigated the effect of lithium insertion on the electrochromic behavior of oxide films prepared by the sol-gel process. The kinetics and thermodynamics of electrochemical intercalation of lithium into Li {sub x}WO{sub 3} and Li {sub x}(WO{sub 3}:Li) films prepared by the sol-gel process were investigated. The standard Gibbs energy for lithium intercalation was calculated. The chemical diffusion coefficients, D, of lithium intercalation into oxide were measured by galvanostatic intermittent titration technique (GITT) as functions of the depth of lithium intercalation.

  12. Kinetics and thermodynamic behavior of WO{sub 3} and WO{sub 3}:P thin films

    Energy Technology Data Exchange (ETDEWEB)

    Avellaneda, Cesar O.; Bulhoes, Luis O.S. [Laboratorio Interdisciplinar de Eletroquimica e Ceramica-LIEC, Departamento de Quimica, Universidade Federal de Sao Carlos, C.P. 676, CEP 13565-905, Sao Carlos-SP (Brazil)

    2006-03-06

    There is a considerable interest in the research and development of materials and devices, that can be used for optical switching of large-scale glazings. Several potential switching technologies are available for glazings, including those based on electrochromic, thermochromic and photochromic phenomena. One of the most promising technologies for optical switching devices is electrochromism (EC). In order to improve the electrochromic properties of tungsten oxide, we have investigated the effect of phosphorous insertion on the electrochromic behavior of oxide films prepared by the sol-gel process. The kinetics and thermodynamics of electrochemical intercalation of lithium into Li{sub x}WO{sub 3} and Li{sub x}WO{sub 3}:P films prepared by the sol-gel process were investigated. The standard Gibbs energy for lithium intercalation was calculated. The chemical diffusion coefficients, D, of lithium intercalation into oxide, were measured by galvanostatic intermittent titration technique (GITT), as functions of the depth of lithium intercalation. (author)

  13. Improvement of radiopurity level of enriched $^{116}$CdWO$_4$ and ZnWO$_4$ crystal scintillators by recrystallization

    CERN Document Server

    Barabash, A S; Bernabei, R; Borovlev, Yu A; Cappella, F; Caracciolo, V; Cerulli, R; Danevich, F A; Incicchitti, A; Kobychev, V V; Konovalov, S I; Laubenstein, M; Mokina, V M; Polischuk, O G; Safonova, O E; Shlegel, V N; Tretyak, V I; Tupitsyna, I A; Umatov, V I; Zhdankov, V N

    2016-01-01

    As low as possible radioactive contamination of a detector plays a crucial role to improve sensitivity of a double beta decay experiment. The radioactive contamination of a sample of $^{116}$CdWO$_4$ crystal scintillator by thorium was reduced by a factor $\\approx 10$, down to the level 0.01 mBq/kg ($^{228}$Th), by exploiting the recrystallization procedure. The total alpha activity of uranium and thorium daughters was reduced by a factor $\\approx 3$, down to 1.6 mBq/kg. No change in the specific activity (the total $\\alpha$ activity and $^{228}$Th) was observed in a sample of ZnWO$_4$ crystal produced by recrystallization after removing $\\approx 0.4$ mm surface layer of the crystal.

  14. Improvement of radiopurity level of enriched 116CdWO4 and ZnWO4 crystal scintillators by recrystallization

    Science.gov (United States)

    Barabash, A. S.; Belli, P.; Bernabei, R.; Borovlev, Yu. A.; Cappella, F.; Caracciolo, V.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Kobychev, V. V.; Konovalov, S. I.; Laubenstein, M.; Mokina, V. M.; Polischuk, O. G.; Safonova, O. E.; Shlegel, V. N.; Tretyak, V. I.; Tupitsyna, I. A.; Umatov, V. I.; Zhdankov, V. N.

    2016-10-01

    As low as possible radioactive contamination of a detector plays a crucial role to improve sensitivity of a double beta decay experiment. The radioactive contamination of a sample of 116CdWO4 crystal scintillator by thorium was reduced by a factor ≈10, down to the level 0.01 mBq/kg (228Th), by exploiting the recrystallization procedure. The total alpha activity of uranium and thorium daughters was reduced by a factor ≈3, down to 1.6 mBq/kg. No change in the specific activity (the total α activity and 228Th) was observed in a sample of ZnWO4 crystal produced by recrystallization after removing ≈0.4 mm surface layer of the crystal.

  15. Electrochromic response of WO3 and WO3-TiO2 thin films prepared from water-soluble precursors and a block copolymer template

    Directory of Open Access Journals (Sweden)

    Takashi Kuroki

    2016-12-01

    Full Text Available Electrochromic tungsten trioxide (WO3 thin films are attracting renewed attention as transmittance-controllable windows for use in automobile, aircraft, and building applications. In order to achieve high electrochromic performance, high cycle stability, and high reliability, the microstructure and compositional homogeneity of WO3 thin films have to be optimized. In this study, non-doped WO3 and TiO2-doped WO3 thin films were fabricated from water-soluble precursors of tungsten and titanium, and their electrochromic response was investigated. Amorphous WO3 and TiO2-doped WO3 thin films were fabricated by calcining the spin-coated films at 573 K. The use of a PEO-PPO-PEO block copolymer as a porogen facilitated the redox reactions occurring on the thin film/electrolyte interface. Although the effect of TiO2-doping on the cycle stability of WO3 thin films has not been fully elucidated, this study demonstrated that TiO2 doping up to 15 mol% effectively enhanced the cycle stability.

  16. Room temperature synthesis of Ni-based alloy nanoparticles by radiolysis.

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina Maria; Berry, Donald T.; Lu, Ping; Leung, Kevin; Provencio, Paula Polyak; Stumpf, Roland Rudolph; Huang, Jian Yu; Zhang, Zhenyuan

    2009-09-01

    Room temperature radiolysis, density functional theory, and various nanoscale characterization methods were used to synthesize and fully describe Ni-based alloy nanoparticles (NPs) that were synthesized at room temperature. These complementary methods provide a strong basis in understanding and describing metastable phase regimes of alloy NPs whose reaction formation is determined by kinetic rather than thermodynamic reaction processes. Four series of NPs, (Ag-Ni, Pd-Ni, Co-Ni, and W-Ni) were analyzed and characterized by a variety of methods, including UV-vis, TEM/HRTEM, HAADF-STEM and EFTEM mapping. In the first focus of research, AgNi and PdNi were studied. Different ratios of Ag{sub x}- Ni{sub 1-x} alloy NPs and Pd{sub 0.5}- Ni{sub 0.5} alloy NP were prepared using a high dose rate from gamma irradiation. Images from high-angle annular dark-field (HAADF) show that the Ag-Ni NPs are not core-shell structure but are homogeneous alloys in composition. Energy filtered transmission electron microscopy (EFTEM) maps show the homogeneity of the metals in each alloy NP. Of particular interest are the normally immiscible Ag-Ni NPs. All evidence confirmed that homogeneous Ag-Ni and Pd-Ni alloy NPs presented here were successfully synthesized by high dose rate radiolytic methodology. A mechanism is provided to explain the homogeneous formation of the alloy NPs. Furthermore, studies of Pd-Ni NPs by in situ TEM (with heated stage) shows the ability to sinter these NPs at temperatures below 800 C. In the second set of work, CoNi and WNi superalloy NPs were attempted at 50/50 concentration ratios using high dose rates from gamma irradiation. Preliminary results on synthesis and characterization have been completed and are presented. As with the earlier alloy NPs, no evidence of core-shell NP formation occurs. Microscopy results seem to indicate alloying occurred with the CoNi alloys. However, there appears to be incomplete reduction of the Na{sub 2}WO{sub 4} to form the W

  17. Temperature and acidity effects on WO{sub 3} nanostructures and gas-sensing properties of WO{sub 3} nanoplates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Huili [School of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin 300384 (China); Liu, Zhifang; Yang, Jiaqin; Guo, Wei [Department of Materials Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (MOE), TKL of Metal and Molecule-based Material Chemistry, Synergetic Innovation Centre of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China); Zhu, Lianjie, E-mail: zhulj@tjut.edu.cn [School of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin 300384 (China); Zheng, Wenjun, E-mail: zhwj@nankai.edu.cn [Department of Materials Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (MOE), TKL of Metal and Molecule-based Material Chemistry, Synergetic Innovation Centre of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China)

    2014-09-15

    Graphical abstract: Generally, large acid quantity and high temperature are beneficial to the formation of anhydrous WO3, but the acidity effect on the crystal phase is weaker than that of temperature. Large acid quantity is found helpful to the oriented growth of tungsten oxides, forming a nanoplate-like product. - Highlights: • Large acid quantity is propitious to the oriented growth of a WO{sub 3} nanoplate. • Effect of acid quantity on crystal phases of products is weaker than that of temperature. • One step hydrothermal synthesis of WO{sub 3} is facile and can be easily scaled up. • A WO{sub 3} nanoplate shows a fast response and distinct sensing selectivity to acetone gas. - Abstract: WO{sub 3} nanostructures were successfully synthesized by a facile hydrothermal method using Na{sub 2}WO{sub 4}·2H{sub 2}O and HNO{sub 3} as raw materials. They are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The specific surface area was obtained from N{sub 2} adsorption–desorption isotherm. The effects of the amount of HNO{sub 3}, hydrothermal temperature and reaction time on the crystal phases and morphologies of the WO{sub 3} nanostructures were investigated in detail, and the reaction mechanism was discussed. Large amount of acid is found for the first time to be helpful to the oriented growth of tungsten oxides, forming nanoplate-like products, while hydrothermal temperature has more influence on the crystal phase of the product. Gas-sensing properties of the series of as-prepared WO{sub 3} nanoplates were tested by means of acetone, ethanol, formaldehyde and ammonia. One of the WO{sub 3} nanoplates with high specific surface area and high crystallinity displays high sensitivity, fast response and distinct sensing selectivity to acetone gas.

  18. Application of PbWO4 crystal scintillators in experiment to search for double beta decay of 116Cd

    CERN Document Server

    Danevich, F A; Kobychev, V V; Kropivyansky, B N; Nagorny, S S; Nikolaiko, A S; Poda, D V; Tretyak, V I; Yurchenko, S S; Grinyov, B V; Nagornaya, L L; Pirogov, E N; Ryzhikov, V D; Brudanin, V B; Fedorov, M; Korzhik, M; Lobko, A; Miussevitch, O; Solsky, I M

    2004-01-01

    PbWO4 crystal scintillators are discussed as an active shield and light-guides in 116Cd double beta decay experiment with CdWO4 scintillators. Scintillation properties and radioactive contamination of PbWO4 scintillators were investigated. Energy resolution of CdWO4 detector, coupled to PbWO4 crystal as a light-guide, was tested. Efficiency of PbWO4-based active shield to suppress background from the internal contamination of PbWO4 crystals was calculated. Using of lead tungstate crystal scintillators as high efficiency 4-pi active shield could allow to build sensitive double beta experiment with 116CdWO4 crystal scintillators.

  19. Photoreactive mesoporous carbon/Bi{sub 2}WO{sub 6} composites: Synthesis and reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Chen Suhua; Yin Zhen [Key Laboratory of Jiangxi Province for Ecological Diagnosis-Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China); Luo Shenglian, E-mail: sllou@hnu.edu.cn [Key Laboratory of Jiangxi Province for Ecological Diagnosis-Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China); Li Xuejun; Yang Lixia; Deng Fang [Key Laboratory of Jiangxi Province for Ecological Diagnosis-Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer We described the preparation and characterization of the mesoprous carbon/Bi{sub 2}WO{sub 6} composites. Black-Right-Pointing-Pointer The photocatalytic activities of the composites were also investigated. Black-Right-Pointing-Pointer With the combination of photocatalysts and mesoporous carbon, increased separation efficiency of photoinduced electron-hole pairs and larger specific surface areas can be achieved. Black-Right-Pointing-Pointer And to our knowledge, this is the first report concerning Bi{sub 2}WO{sub 6} nanoparticles loaded on a mesoprous carbon. - Abstract: In order to develop highly efficient visible-light induced photocatalysts, Bi{sub 2}WO{sub 6} powders and mesoporous carbon (MC)-modified Bi{sub 2}WO{sub 6} (MC/Bi{sub 2}WO{sub 6}) photocatalysts were synthesized via a simple hydrothermal process in this paper. The samples of Bi{sub 2}WO{sub 6} and MC/Bi{sub 2}WO{sub 6} were characterized by X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM) and BET surface area analysis, and their photocatalytic activity were evaluated by photocatalytic decoloration of rhodamine B (RhB) aqueous solution under visible light. It was found that the presence of MC could significantly improve the crystallization of Bi{sub 2}WO{sub 6} species and photoabsorption property of Bi{sub 2}WO{sub 6} in the visible region. The results also showed that the BET surface areas of MC/Bi{sub 2}WO{sub 6} composites were larger than that of the pure Bi{sub 2}WO{sub 6} and the photocatalytic activity of the MC/Bi{sub 2}WO{sub 6} is much higher than that of Bi{sub 2}WO{sub 6} with the optimum effect occurring at R{sub MC} = 0.10 (the weight ratio of MC to Bi{sub 2}WO{sub 6}). Close investigation revealed that the surface area, grain size and charge transfer of the as-prepared MC/Bi{sub 2}WO{sub 6} composites could improve the photocatalytic activities.

  20. Multiple horizontal transfers of bacteriophage WO and host Wolbachia in fig wasps in a closed community

    Directory of Open Access Journals (Sweden)

    Ningxin eWang

    2016-02-01

    Full Text Available Wolbachia-bacteriophage WO is a good model system for studying interactions between bacteria and viruses. Previous surveys of insect hosts have been conducted via sampling from open or semi-open communities; however, no studies have reported the infection patterns of phage WO of insects living in a closed community. Figs and fig wasps form a peculiar closed community in which the Ficus tree provides a compact syconium habitat for a variety of fig wasps. Therefore, in this study, we performed a thorough survey of Wolbachia and bacteriophage WO infection patterns in a total of 1406 individuals from 23 fig wasps species living on three different fig tree species. The infection rates of Wolbachia and phage WO were 82.6% (19/23 and 39.1% (9/23, respectively. Additionally, phage WO from fig wasps showed strong insect host specificity based on orf7 sequences from fig wasps and 21 other insect species. Probably due to the physical barrier of fig syconium, most phage WO from fig wasps form a special clade. Phylogenetic analysis showed the absence of congruence between WO and host Wolbachia, WO and insect host, as well as Wolbachia and fig wasps, suggesting that both Wolbachia and phage WO exchanged frequently and independently within the closed syconium. Thus, the infection pattern of bacteriophage WO from fig wasps appeared quite different from that in other insects living outside, although the effect and the transfer routes of phage WO are unclear, which need to be investigated in the future.

  1. Cómo la Web of Science (WoS de Thomson Reuters habría confundido dos revistas distintas con el mismo título durante años: el caso de “Journal of Public Relations Research”

    Directory of Open Access Journals (Sweden)

    Matilla, Kathy

    2016-06-01

    Full Text Available A description of how a conspicuous anomaly in the Web of Science (WoS database was detected. Beginning in 2002 the WoS randomly mistook and interspersed numerous articles from two different journals, one American and the other South Korean, both specialized in public relations and sharing the same title: Journal of Public Relations Research. The case is especially noteworthy since these are two publications written in very different languages (English and Korean, with different ISSN numbers and editorial outlooks, and whose respective volumes share neither authors nor content.Descripción del proceso mediante el cual se habría detectado una notable anomalía en la base de datos bibliográficos de la Web of Science (WoS. Concretamente, desde el año 2002 la WoS habría confundido y entremezclado aleatoriamente numerosos artículos de dos revistas distintas, ambas especializadas en relaciones públicas, una norteamericana y otra surcoreana, que comparten un mismo título: Journal of Public Relations Research. El caso es especialmente relevante al tratarse de dos publicaciones escritas en idiomas totalmente distintos (inglés y coreano, con diferentes números de ISSN y con distintas líneas editoriales, en cuyos respectivos volúmenes no coinciden ni autores, ni contenido.

  2. Development of a new electrolyte for deposition of Ni-W alloys

    DEFF Research Database (Denmark)

    Mizushima, Io; Tang, Peter Torben; Hansen, Hans Nørgaard

    2005-01-01

    content in the electrodeposits (by energy dispersive X-ray analysis), voltammetry studies and characterization of complex formation by UV-spectrometry. HighWcontent and current efficiency could be realized by using electrolytes containing all of the three complexing agents. The results show that small......In the present work, the effect of the complexing agents citrate, glycine and triethanolamine (TEA) on the electrodeposition of Ni-W layers from electrolytes based on NiSO4 and Na2WO4, is investigated. The investigations include measurement of the current efficiencies, determination of the tungsten...

  3. Effect of crystallization water on the structural and electrical properties of CuWO{sub 4} under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Li; Yan, Jiejuan; Liu, Cailong; Liu, Xizhe; Han, Yonghao, E-mail: hanyh@jlu.edu.cn, E-mail: cc060109@qq.com; Gao, Chunxiao, E-mail: hanyh@jlu.edu.cn, E-mail: cc060109@qq.com [State Key Lab for Superhard Materials, Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Ke, Feng; Wang, Qinglin [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 (China); Li, Yanchun [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Science, Beijing 100049 (China); Ma, Yanzhang [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 (China); Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

    2015-11-16

    The effect of crystallization water on the structural and electrical properties of CuWO{sub 4} under high pressure has been investigated by in situ X-ray diffraction and alternating current impedance spectra measurements. The crystallization water was found to be a key role in modulating the structural stability of CuWO{sub 4} at high pressures. The anhydrous CuWO{sub 4} undergoes two pressure-induced structural transitions at 8.8 and 18.5 GPa, respectively, while CuWO{sub 4}·2H{sub 2}O keeps its original structure up to 40.5 GPa. Besides, the crystallization water makes the electrical transport behavior of anhydrous CuWO{sub 4} and CuWO{sub 4}·2H{sub 2}O quite different. The charge carrier transportation is always isotropic in CuWO{sub 4}·2H{sub 2}O, but anisotropic in the triclinic and the third phase of anhydrous CuWO{sub 4}. The grain resistance of CuWO{sub 4}·2H{sub 2}O is always larger than that of anhydrous CuWO{sub 4} in the entire pressure range. By analyzing the relaxation response, we found that the large number of hydrogen bonds can soften the grain characteristic frequency of CuWO{sub 4}·2H{sub 2}O over CuWO{sub 4} by one order of magnitude.

  4. Hydrogen-treated commercial WO3 as an efficient electrocatalyst for triiodide reduction in dye-sensitized solar cells.

    Science.gov (United States)

    Cheng, Ling; Hou, Yu; Zhang, Bo; Yang, Shuang; Guo, Jian Wei; Wu, Long; Yang, Hua Gui

    2013-07-07

    The electrocatalytically inactive commercial WO3 can be transformed into an efficient counter electrode (CE) material for dye-sensitized solar cells (DSCs) via facile hydrogen treatment. The energy conversion efficiency of the DSCs with the hydrogen-treated WO3 CE was 5.43%, while the corresponding value for commercial WO3 with the stoichiometric surface was only 0.63%.

  5. Effect of nonmagnetic substituents Mg and Zn on the phase competition in the multiferroic antiferromagnet MnWO4

    OpenAIRE

    Meddar, Lynda; Josse, Michael; Deniard, Philippe; La, Carole; André, Gilles; Damay, Françoise; Petricek, Vaclav; Jobic, Stéphane; Whangbo, Myung-Hwan; Maglione, Mario; Payen, Christophe

    2010-01-01

    The effects of substituting nonmagnetic Mg2+ and Zn2+ ions for the Mn2+ (S = 5/2) ions on the structural, magnetic and dielectric properties of the multiferroic frustrated antiferromagnet MnWO4 were investigated. Polycrystalline samples of Mn1-xMgxWO4 and Mn1-xZnxWO4 (0

  6. Photocatalytic degradation of 2-propanol and phenol using Au loaded MnWO4 nanorod under visible light irradiation

    CSIR Research Space (South Africa)

    Chakraborty, AK

    2012-06-01

    Full Text Available Single crystalline MnWO4 nanorod has been prepared by low temperature hydrothermal reaction at 180 °C. The prepared MnWO4 possesses band gap of 2.63 eV. Photochemical decomposition method has been followed to disperse Au nanoparticles onto MnWO4...

  7. Visible-light photocatalytic activity of graphene oxide-wrapped Bi{sub 2}WO{sub 6} hierarchical microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Jiali; Yu, Hongwen, E-mail: yuhw@iga.ac.cn; Li, Haiyan; Sun, Lei; Zhang, Kexin; Yang, Hongjun

    2015-07-30

    Graphical abstract: - Highlights: • GO/Bi{sub 2}WO{sub 6} are readily fabricated by facile bubbling pretreatment and freeze drying. • GO/Bi{sub 2}WO{sub 6} possess excellent photocatalytic activity under visible light irradiation. • The visible light activity of GO/Bi{sub 2}WO{sub 6} is affected by the amount of GO. • The photostablity of GO is due to the photo-generated electrons transfer to Bi{sub 2}WO{sub 6}. - Abstract: A facile approach of fabricating homogeneous graphene oxide (GO)-wrapped Bi{sub 2}WO{sub 6} microspheres (GO/Bi{sub 2}WO{sub 6}) is developed. The transmission electron microscopy (TEM) results show that a heterojunction interface between GO and Bi{sub 2}WO{sub 6}. The UV–vis diffuse reflection spectra (DRS) reveal that the as-prepared GO/Bi{sub 2}WO{sub 6} composites own more intensive absorption in the visible light range compared with pure Bi{sub 2}WO{sub 6}. These characteristic structural and optical properties endow GO/Bi{sub 2}WO{sub 6} composites with enhanced photocatalytic activity. The enhanced photocatalytic activity of the GO/Bi{sub 2}WO{sub 6} is attributed predominantly to the synergetic effect between GO and Bi{sub 2}WO{sub 6}, causing rapid generation and separation of photo-generated charge carriers.

  8. Effect of heat generation from bone cement on bone tissue in total knee arthroplasty; Jinko kansetsu okikaeji no one cement no hatsunetsu ga seitai soshiki ni oyobosu eikyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, M.; Uchida, T. [Kobe University, Kobe (Japan); Iwatsubo, T. [Kobe University, Kobe (Japan). Faculty of Engineering; Kurosawa, M.; Hashimoto, Y. [Kobe University, Kobe (Japan). Faculty of Medicine; Fukushima, H.

    1998-01-25

    Bone cement is often applied to fix the components in a surgical operation, such as TKA (total knee arthroplasty). In this paper, we consider the effect of heat generation from bone cement on bone tissue in TKA by using numerical simulation. First, we applied an axisymmetric model of tibia to finite element method and analyzed heat generation of bone cement. To confirm the results of analysis by experiment, we measured the temperature determined by 6 points i.e., 2 points each in component-cement interface, cement and bone-cement interface. As a result, the temperature determined by analysis agrees with that determined by experiment. Next, we proposed the evaluation formula of the bone necrosis. We constructed a bone necrosis map from the simulation. From the map, we found that the bone necrosis region was about 2 mm from the bone-cement interface. In addition, the bone necrosis is severe at the base of the tibial component. 7 refs., 15 figs., 3 tabs.

  9. Study on the performances of handling and stability influenced by the differential terms in the state variables; Soansei ni okeru jotai hensunai no bibun yoso ga seino ni oyobosu eikyo no kento

    Energy Technology Data Exchange (ETDEWEB)

    Sugasawa, F. [Tamagawa University, Tokyo (Japan); Mori, H. [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    The analysis method using the system matrix for state variables can not be applied to the analysis for the system has Complex Cornering Stiffness. The reason is there are differential terms in the state variables. It is found that the differential terms m the state variables can be changed to the constant terms in another state variables. 4 refs., 9 figs.

  10. Effect of surface active compounds on growth and adhesion of anchorage-dependent animal cells at liquid/liquid interface; Eki/ekikaimen ni okeru fuchaku izonsei dobutsu saibo no zoshoku oyobi fuchaku ni taisuru kaimen kassei busshitsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, Y.; Oshima, T.; Sato, M. [Gunma Univ., Kiryu (Japan). Faculty of Technology

    1998-03-01

    A cell cultivation using a liquid/liquid (culture medium/fluorocarbon) interface has been practiced as a novel culturing method for anchorage-dependent animal cells, and it is known that cell adhesion at the interface is dependent on the contaminants contained in the hydrophobic liquid. Substances effective for the adhesion and growth of cells are investigated using various surfactants. As a result of comparison of ionic and nonionic surfactants, cell adhesion is observed when ionic surfactant is used, indicating the importance of the electric charge of surfactant. Cell growth is better when ionic surfactant is added to fluorocarbon than when surfactant is added to the culture medium. The cell growth using fluorocarbon added with pentafluorobenzoyl chloride and perfluorooctanoyl chloride is similar to that of culturing using polystyrene, and the importance of surfactant addition to fluorocarbon is indicated. 7 refs., 4 figs.

  11. Decomposition of yallourn coal by microwave plasma. Effect of Plasma source on the product distribution; Maikuroha purazuma ni yoru yarun tan no tenkan hanno. Purazumagasu shu ga seiseibutsu bunpu ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, Osamu; Marushima, Wataru; Kobayashi, Motoki; Onoe, Kaoru; Yamaguchi, Tatsuaki [Chiba Institute of Technology, Chiba (Japan). Department of Industrial Chemistry; Kawai, Satoshi; Ito, Yoichi [Mitsubishi Chemical Corp., Tokyo (Japan)

    1999-08-20

    This report described the experiments that used plasma reaction between plasma source gases and brown coal (Yallourn). The properties of the products were influenced by changes of the experimental conditions. The reaction experiments were carried out with 2.45 GHz microwave plasma by using hydrogen, helium and argon systems. Ratios of coal conversion (X{sub c}) were as follows; X{sub c} (H{sub 2}) was 33.2%, X{sub c} (He) was 13.7%, and X{sub c} (Ar) was 24.8% at reaction time 1 minute. No practical difference was detected after 3 minutes. Yields of benzene soluble oily fractions (Y{sub oil}) were as follows; Y{sub oil} (H{sub 2}) was 6.0%, Y{sub oil} (He) was 3.4% and Y{sub oil} (Ar) was 8.7% at 1 minute, while at 3 minutes Y{sub oil} (H{sub 2}) was 4.9%, Y{sub oil} (He) was 4.1% and Y{sub oil} (Ar) was 7.7%. In addition at 1 minute, no difference of molecular weight distribution measured by MALDI-TOFMS spectra and GC was observed, while the polymerization of oily products under argon or hydrogen system was occurred after 3 minutes. Yields of gaseous components (Y{sub gas}) were as follows; Y{sub gas} (H{sub 2}) was 48.1%, Y{sub gas} (He) was 50.9% and Y{sub gas} (Ar) was 46.6% at 3 minutes. Typical patterns of time change in molar fraction of gaseous components by GC were shown on each plasma source gas. (author)

  12. Effects of applied stress and plastic strain on. gamma. r reversible. epsilon. martensitic transformation in high Mn alloy polyctystals. Ko Mn tetsu gokin takessho ni okeru. gamma. r reversible. epsilon. martensite hentai ni oyobosu gairyoku to hizumi no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Tomota, Y.; Piao, M.; Hasunuma, T.; Kimura, Y. (Ibaraki Univ., Ibaraki (Japan))

    1990-06-20

    The influences of applied stress and plastic strain on a transformation austenite ({gamma}) to hcp martensite ({epsilon}) were studied on Fe-16wt%Mn, Fe-24wt%Mn, and Fe-24%Mn-6%Si alloy, and a transformation mechanism and a shape memory phenomenon were more deeply examined. As the quenching structure of three kinds of the alloys consists of two phases of {gamma} and {epsilon}, the specimens were cooled after heated above the A {sub f} temperature to keep {gamma} single phase, and then the tensile tests were carried out. Positive temperature dependence was found under the 0.2% proof stress due to stress-induced {gamma}{yields} {epsilon} transformation in each of Fe-Mn alloy and Fe-24%Mn-6%Si alloy. When {gamma} phase of Fe-24%Mn alloy stabilized due to cyclic transformation was stretched at room temperature, the yield stress was remarkably lowered by the stress-induced {gamma}{r arrow}{epsilon} transformation. When the specimens were stretched at 523K under stress which was larger than the yield strength and then cooled, the elongation along the applied stress direction due to martensitic tranformation was recognized. A shape recovery was remarkable in Si content alloys. 22 refs., 5 figs.

  13. Electrochemical impedance spectroscopy analysis on effect of steel fiber addition on corrosion of steel rod in mortar; Morutaruchu no tekkin no fushoku ni oyobosu suchiru fuaiba tenka no eikyo no denki kagaku inpidansu supekutorosukopi ni yoru kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Sakashita, S.; Nakayama, T.; Hamasaki, Y.; Sugii, K. [Kobe Steel Ltd., Kobe (Japan); Sugimoto, K. [Tohoku University, Miyagi (Japan). Department of Metallurgy

    1999-11-15

    The effect of steel fiber (SF) addition to concrete on the corrosion behavior of steel reinforcement was studied by immersion corrosion tests in a 3 mass % NaCl solution for 363 day. The tests were conducted on steel rod/mortar specimens with different SF content (0-2 vol %), and corrosion potentials and electrochemical impedance of the specimens were measured during the tests. Corrosion potentials of the specimens were not so changed by the SF content. Electrochemical impedance measured at corrosion potentials was analyzed to get charge transfer resistance (R{sub ct}) using an equivalent electrical circuit with the R{sub ct}, Warburg impedance and a constant-phase element. The corrosion rate of steel rod in mortar estimated from the reciprocal of the R{sub ct} decreased with increasing of SF content in mortar, and correlated well with the rust area of steel rod measured after immersion corrosion tests. This shows that the electrochemical impedance measurement is the useful diagnosis method of corrosion of steel in concrete. The corrosion inhibition of steel rod in mortar by the SF addition was thought to be attributed to the consumption of dissolved oxygen by the corrosion of SF in mortar. (author)

  14. Assessment of a Mega-Float on water quality and ecosystem in Tokyo bay; Choogata futaishiki kaiyo kozobutsu ga Tokyowan no suishitsu to seitaikei ni oyobosu eikyo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Kyozuka, Y.; Hu, C.; Hasemi, H. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Hikai, A.

    1997-08-01

    The effect on the marine environment in the bay when a Mega-Float is installed in a bay was investigated. The physical process such as a residual flow (including tidal currents, water temperature, salt, density, and density currents), and the ecosystem model for which floating organic matter and plankton are handled were incorporated to develop a program for water quality calculation in a bay. The program was used for Tokyo Bay and compared with the conventional calculation result and the oceanograhpic observation result. Simultaneously, the effect on the Mega-Float was considered. On the flow in Tokyo Bay in summer, the calculation result that comparatively coincided with the observation value in a residual flow level was obtained. The horizontal distribution of COD comparatively coincides with the existing observation result. The influence that the Mega-Float exerts on the flow, water temperature, water quality, and ecosystem in the ambient sea area was little and local in the calculation scale (L {times} B {times} d = 6 km {times} 3 km {times} 2 m) of this time. However, the difference occurring due to the design position must also be investigated in future. 12 refs., 8 figs., 5 tabs.

  15. Effects of dissolved oxygen concentration and flow velocity on corrosion of carbon steel in tap water; Suidosuichu ni okeru tansoko fushoku ni oyobosu yoson sanso nodo to ryusoku no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Murata, M.; Ouchi, M. [Miura Institute of Research and Development, Ehime (Japan); Fujii, T.; Shiraishi, H.; Kawahito, A. [Miura Co. Ltd., Ehime (Japan)

    1998-05-15

    Discussions were given on the effects of dissolved oxygen (DO) concentration and flow velocity on temporary corrosion of carbon steel in tap water by using a membrane-type deaerator which uses a hollow fiber membrane for air separation. In deaerated air with DO at 0.5 mg per liter, active corrosion took place, in which corrosion rate increases with flow velocity in a range from 0.5 to 2.0 m/s. The corrosion rate in a carbon steel in deaerated air with flow velocity of 0.5 m/s and DO of 0.5 mg per liter decreased to 1/4 to 1/5 of that in non-deaerated water, showing effectiveness in preventing corrosion and red water in pipings in buildings. The corrosion prevention effect is more excellent especially in low flow velocity regions, meaning it being suitable for corrosion prevention in building pipings for water supply which is low in flow velocity and often subjected to stagnation. It was found that, even at about the same flow velocity, the deaerated water is on the safer side than the non-deaerated water. With waters having DO of 2.0 and 4.0 mg per liter, the corrosion rate decreased when flow velocity is higher than 1 m/s, with appearance of passivation trend. There is a relation with high reproducibility between the corrosion rate in the carbon steel and oxygen supply amount, whereas the curve showed a maximum value. This maximum value is thought a transition point from active state corrosion to passive state corrosion. 9 refs., 6 figs., 2 tabs.

  16. Effects of passive control boundary layer around the throat on a transonic diffuser; Throat kinbo ni okeru kyokaiso no passive control ga sen`onsoku diffuser ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yaga, M.; Nagai, M.; Haga, T. [Univ. of the Ryukyus, Okinawa (Japan). College of Engineering; Miyara, T. [University of the Ryukyus, Okinawa (Japan). Faculty of Medicine; Tomita, n. [Hitachi, Ltd., Tokyo (Japan)

    1996-03-25

    The effects of a passive control boundary layer applied around the throat on a transonic diffuser were investigated experimentally by wall static pressure measurements and by schlieren optical observations. The experiments were conducted using three kinds of the diffuser walls, one was a solid wall and the other two were porous with a 30 mm or 50 mm-long cavity underneath enabling the flow around the shock wave to circulate through the porous wall. The results show that the Mach waves normal to the flow were observed when diffusers were almost choked and that the pressure fluctuations in a transonic diffuser were greatly reduced by passive control. According to the frequency analysis, the frequency range attenuated by passive control is between about 700 Hz and 1 kHz regardless of the length of the cavities. 15 refs., 7 figs.

  17. Optical spectroscopy of rare-earth ions doped KY(WO4)2 thin films

    NARCIS (Netherlands)

    García-Revilla, S.; Valiente, R.; Romanyuk, Y.E.; Utke, I.; Pollnau, Markus

    2004-01-01

    KY(WO4)2 thin films doped with Dy3+, Tb3+, Yb3+, were grown onto KY(WO4)2 substrates using liquid-phase epitaxy. Spectroscopic investigations of the grown layers were performed. Obtained results were compared with spectra given for bulk crystals. Upconversion experiments after direct Yb3+ excitation

  18. Charge carriers and dc polarization phenomena in solid Na2WO4

    NARCIS (Netherlands)

    Bottelberghs, P.H.; Everts, E.

    1975-01-01

    Ionic transport measurements based on the Tubandt method have been performed in all three solid phases of Na2WO4 at temperatures between 550 and 600°C in air. It is shown that tNa+ = 1.00 in all cases. Ag is oxidized anodically to Ag+ at Ag/Na2WO4 interfaces. Cathodically only (air) oxygen reduction

  19. Oxidative degradation of salicylic acid by sprayed WO{sub 3} photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Mohite, S.V.; Rajpure, K.Y., E-mail: rajpure@yahoo.com

    2015-10-15

    Highlights: • The photoactivity of sprayed WO{sub 3} thin film. • Photoelectrocatalytic degradation of salicylic acid. • Reaction kinetics and mineralization of pollutants by COD. - Abstract: The WO{sub 3} thin films were deposited using spray pyrolysis technique. The prepared WO{sub 3} thin films were characterized using photoelectrochemical (PEC), X-ray diffraction, atomic force microscopy (AFM), and UV–vis absorbance spectroscopy techniques. PEC measurements of WO{sub 3} films deposited at different deposition temperatures were carried out to study photoresponse. The maximum photocurrent (I{sub ph} = 261 μA/cm{sup 2}) was observed for the film deposited at the 225 °C. The monoclinic crystal structure of WO{sub 3} has been confirmed from X-ray diffraction studies. AFM studies were used to calculate particle size and average roughness of the films. Optical absorbance was studied to estimate the bandgap energy of WO{sub 3} thin film which was about 2.65 eV. The photoelectrocatalytic activity of WO{sub 3} film was studied by degradation of salicylic acid with reducing concentrations as function of reaction time. The WO{sub 3} photocatalyst degraded salicylic acid to about 67.14% with significant reduction in chemical oxygen demand (COD) value.

  20. Influence of disordered morphology on electrochromic stability of WO{sub 3}/PPy

    Energy Technology Data Exchange (ETDEWEB)

    Gaikwad, Digambar K. [D. Y. Patil College of Engineering & Technology, Kasaba Bawada, Kolhapur, 416006, Maharashtra (India); Mali, Sawanta S.; Hong, Chang K. [Polymer Energy Materials Laboratory, Department of Advanced Chemical Engineering, Chonnam National University, Gwangju, 500-757 (Korea, Republic of); Kadam, Anamika V., E-mail: anamikasonavane@rediff.com [D. Y. Patil College of Engineering & Technology, Kasaba Bawada, Kolhapur, 416006, Maharashtra (India); D.Y. Patil Medical University, Kasaba Bawada, Kolhapur, 416006, Maharashtra (India)

    2016-06-05

    Tungsten oxide (WO{sub 3}) films are critical for smart windows because of their capacity of varying the throughput of visible light and solar energy. This study highlights the evolution of structural and morphological changes of electrodeposited WO{sub 3} thin films coated with polypyrrole (PPy) by using chemical bath deposition. The structural and surface properties of WO{sub 3} thin films were studied using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electrochemical stability was inspected using repetitive cyclic voltammetry (CV) cycles for each sample in LiClO{sub 4}-PC electrolyte for prolonged periods. The results showed an improvement in the electrochemical stability after the CV study. - Graphical abstract: Mechanism: A schematic of the mechanism is proposed in above fig. The mechanism is based on three step process: (i) WO{sub 3} coated on ITO by electrodeposition followed by thermal treatment. It produces ordered nanoarrayed morphology. (ii) A second step involving deposition of PPy by chemical bath deposition on ITO. It possesses globular morphology. (iii) When PPy coated on WO{sub 3}, PPy applies shearing force on WO{sub 3} and produces disordered nanoarrayed morphology. - Highlights: • Nanoarrayed WO{sub 3}/PPy composite was synthesized. • Interplanar spacing enhances due to PPy coating. • PPy applies shearing force on WO{sub 3} produces disordered morphology. • Nanocomposite showed high stability in LiClO{sub 4}-PC.

  1. Photodegradation of Malachite Green by Nanostructured Bi2WO6 Visible Light-Induced Photocatalyst

    Directory of Open Access Journals (Sweden)

    Yijie Chen

    2012-01-01

    Full Text Available Bi2WO6 photocatalyst was first utilized to degrade malachite green. The effects of the concentration of malachite green, the pH value, and the concentration of Bi2WO6 on the photocatalytic efficiency were investigated. This study presents a strategy to eliminate highly toxic and persistent dyes such as malachite green.

  2. Enhanced visible light photocatalytic activity of Bi2WO6 via modification with polypyrrole

    Science.gov (United States)

    Duan, Fang; Zhang, Qianhong; Shi, Dongjian; Chen, Mingqing

    2013-03-01

    Enhanced visible light photocatalytic activity of Bi2WO6 photocatalyst modified with different amounts of polypyrrole (PPy) was synthesized by 'in situ' deposition oxidative polymerization of pyrrole. The as-prepared PPy/Bi2WO6 composites were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse absorption spectra. The photocatalytic activities of the PPy/Bi2WO6 samples were determined by photocatalytic degradation of rhodamine-B (RhB) and methylene blue (MB) in aqueous solution under visible light irradiation. The results indicated that the existence of PPy did not affect the crystal structure and the morphology of Bi2WO6 photocatalyst, but showed great influences on the photocatalytic activity of Bi2WO6. Besides, an optimal content of PPy on the surface of Bi2WO6 photocatalyst with the highest photocatalytic ability was discovered, and the obtained PPy/Bi2WO6 photocatalysts showed high stability and did not photocorrode during the photocatalytic process. The possible mechanism of enhanced photocatalytic activities of PPy/Bi2WO6 samples was also discussed in this work.

  3. Selective hydrothermal method to create patterned and photoelectrochemically effective Pt/WO3 Interfaces

    NARCIS (Netherlands)

    Zoontjes, Michel G.C.; Huijben, Mark; Baltrusaitis, Jonas; Wiel, van der Wilfred G.; Mul, Guido

    2013-01-01

    A hydrothermal method based on the use of hydrogen peroxide is described to grow a homogeneous layer of tungsten oxide (WO3) on a platinum (Pt) film supported on a silicon wafer. WO3 growth is highly selective for Pt when present on silicon in a patterned arrangement, demonstrating that Pt catalyzes

  4. A simple synthesis of MnWO{sub 4} nanoparticles as a novel energy storage material

    Energy Technology Data Exchange (ETDEWEB)

    Li, Feihui, E-mail: feihuili2012@163.com [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Xu, Xiaoyang, E-mail: xiaoyangxu2012@163.com [School of Science, Tianjin University (China); Huo, Jialei; Wang, Wei [School of Chemical Engineering, Tianjin 300072 (China)

    2015-11-01

    MnWO{sub 4} nanoparticles with the shuttle-like shape were prepared by a simple chemical co-precipitation method and analyzed by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The prepared MnWO{sub 4} was used as the electrode material of a supercapacitor, and its electrochemical performance was studied using cyclic voltammetry, galvanostatic charge/discharge cycles and electrochemical impedance spectroscopy. The MnWO{sub 4} exhibited good electrochemical performance. The MnWO{sub 4} nanoparticles had specific capacitances of 295 F/g at a scan rate of 5 mV/s and 219 F/g at a current density of 0.4 A/g. They also showed good cycle-life stability and low resistance. Therefore, MnWO{sub 4} is a promising electrode material for supercapacitors. - Highlights: • The shuttle-like MnWO{sub 4} nanoparticles have been prepared. • The prepared MnWO{sub 4} nanoparticles exhibit good electrochemical performances. • MnWO{sub 4} is a promising electrode material for supercapacitors.

  5. MnWO{sub 4} nanocapsules: Synthesis, characterization and its electrochemical sensing property

    Energy Technology Data Exchange (ETDEWEB)

    Muthamizh, Selvamani; Suresh, Ranganathan; Giribabu, Krishnamoorthy; Manigandan, Ramadoss; Praveen Kumar, Sivakumar; Munusamy, Settu; Narayanan, Vengidusamy, E-mail: vnnara@yahoo.co.in

    2015-01-15

    Highlights: • Synthesis of MnWO{sub 4} nanocapsules without use of any other external reagent. • High crystalline MnWO{sub 4} was obtained with phase purity. • Electrochemical sensing platform based on MnWO{sub 4} for sensing quercetin. • Micromolar detection ability of MnWO{sub 4} modified GCE. - Abstract: Manganese tungstate (MnWO{sub 4}) was synthesized by surfactant free precipitation method. MnWO{sub 4} was characterized by using various spectroscopic techniques. The phase, crystalline nature and the morphological analysis were carried out using XRD, scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HR-TEM). Further, FT-IR, Raman, and DRS-UV–Vis spectral analysis were carried out in order to ascertain the optical property and the presence of functional groups. From the analysis, the morphology of the MnWO{sub 4} was observed to be in capsules with breadth and thickness were in nm range. The oxidation state of tungsten (W), and manganese (Mn) were investigated using X-ray photo electron spectroscopy (XPS) and electron paramagnetic resonance spectroscopy (EPR). The synthesized MnWO{sub 4} nanocapsules were used to modify glassy carbon electrode (GCE) to detect quercetin.

  6. Conductivity-Type Sensor Based on CNT-WO3 Composite for NO2Detection

    Directory of Open Access Journals (Sweden)

    Takeshi Hashishin

    2008-01-01

    Full Text Available The CNTs with 20–50 nm in diameter were directly grown on Au microgap electrode by means of thermal CVD at 700∘C for 60 minutes under EtOH-Ar-H2 atmosphere (6 kPa. The CNTs with entangled shape formed the network structure with contacting each other. In the CNTs-WO3 composite, WO3 grains with disk shape (50–200 nm were independently trapped. The CNTs-WO3 composite sensor showed the fairly good sensor response (Ra/Rg = 3.8 at 200∘C. The sensor response was greatly improved with CNTs-WO3 composite, comparing with that of CNT sensor (Ra/Rg = 1.05. This phenomenon can be explained by formation of p-n junction, between CNT(p and WO3(n, and thus improvement of NO2 adsorption. The sensor response was decreased with increasing the WO3 amount in CNTs-WO3 composite, suggesting the electronic conduction due to WO3 connection.

  7. Detecting hydrogen using graphene quantum dots/WO3 thin films

    Science.gov (United States)

    Fardindoost, Somayeh; Iraji zad, Azam; Sadat Hosseini, Zahra; Hatamie, Shadie

    2016-11-01

    In the present work we report an approach to resistive hydrogen sensing based on graphene quantum dots (GQDs)/WO3 thin films that work reproducibly at low temperatures. GQDs were chemically synthesized and evenly dispersed in WO3 solution with 1:1 molar ratio. The structural evaluation and crystallization of the prepared films was studied by x-ray diffraction, Raman and scanning electron microscopy (SEM) techniques. The SEM images showed uniform distribution of the GQDs in WO3 films with sizes around 50 nm. Raman experiment showed the GQDs are partially reduced with high edge defects as hydroxyl and carboxyl groups which involve both in bridging between WO3 grains via bindings as well as interacting with target gas molecules. GQDs can develop an electron conductive network and shorten the current transport paths inside the sensitive films. As a result, they improved the poor electrical properties and charge transfer of pure WO3. Resistive hydrogen sensing showed significant decrease in the working temperature for GQDs/WO3 films compared to pure WO3 films. The working temperature of about 150 °C with 15 and 40 s response and recovery times are significant characteristics of the introduced sensing structure. Then palladium (Pd) was added as a catalyst in GQDs/WO3 film to make the sensing materials selective to hydrogen. Pd doped film worked at temperature of 120 °C with high selectivity and improved response magnitude to hydrogen gas.

  8. Optical spectroscopy of rare-earth ions doped KY(WO4)2 thin films

    NARCIS (Netherlands)

    García-Revilla, S.; Valiente, R.; Romanyuk, Y.E.; Utke, I.; Pollnau, M.

    2004-01-01

    KY(WO4)2 thin films doped with Dy3+, Tb3+, Yb3+, were grown onto KY(WO4)2 substrates using liquid-phase epitaxy. Spectroscopic investigations of the grown layers were performed. Obtained results were compared with spectra given for bulk crystals. Upconversion experiments after direct Yb3+ excitation

  9. It sells the fuse business to Buddha Co.; Huzujigyo wo butsusha ni baikyaku

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-09-01

    The Japan energy was announced with that it agreed by selling fuse business unit of U.S.A. Corporation GA-TEC of the full amount fund in major electronic component manufacturer and Carbonrolein of France on eighth. The sale amount is about 1 hundred million 4300 It is (about 170000000 yen) ten thousand dollar, and the business is transferred by the end August. GA-TEC allocates the most part of the sale income for the payback of the debt, and the finance constitution is strengthened. (translated by NEDO)

  10. Bioprocessing of coal. 1. Sekitan no seibutsu kako. 1. ; Sekitan wo datsuryusuru biseibutsu ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, K.; Omura, N.; Saiki, H.; Kono, Y.

    1989-11-01

    In the bioprocessing of coal using biotechnology, desulfurizing microorgaisms were examined. 30-70% of total sulfur in coal is occupied by inorganic sulfur, almost of that is a form of FeS {sub 2}. Using some acidophilic sulfur oxidizing bacteria such as Thiobacillus ferrooxidans and Thermophilic-acidophilic bacterial such as Sulfolobus acidocaldarius, about 90% of inorganic sulfur in coal can be removed in 1 or 2 weeks in pulverized coal-water slurry, a high possibility in practical use is shown. Organic sulfur (total sulfur {minus} inorganic sulfur) is difficult to be removed, since it is combined with carbon in a from of covalent bond. Sulfolobus acidocaldarius can remove both inorganic and organic sulfur simultaneously. One mutant strain of Pseudomonas is excellent at the rate of desulfurization. These organisms must be superior to others, but their desulfurization ratios are generally low. Some bacteria can degrade some kinds of low-rank coals into water soluble liquid fuel, and the ash content is decreased. Bioconversion of low-rank coals to methane gas applying methane enzyme principle, has been proposed, however, still an idea. 81 refs., 5 figs., 15 tabs.

  11. Grasping bed rock geological structures more concretely; Ganban no chishitsu kozo wo yori gutaiteki ni haaku

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Y. [Newjec Inc., Osaka (Japan)

    1997-08-10

    Reported herein is an investigatory analysis system capable of combining the results of plural geophysical explorations (locations of fault, fracture zone, and aquifer, and the identification of geological structures such as the classification of natural ground) and of converting them rationally into ground properties that are required for designing. Also, this conversion technique is verified by use of geological data observed during the tunneling of a water channel at an S point. The elastic wave velocity determined by elastic wave exploration and the resistivity determined by electric/electromagnetic exploration are different physical quantities. However, there are formulas proposed for both of them in which the base rock gap rate {phi} and saturation rate S are the parameters. The rate {phi} and rate S may be determined by solving the formulas as simultaneous equations. As for the quantitative evaluation of ground properties which are necessary for designing underground structures, the rock classification may be estimated from the rate {phi} and the location of gushing water from the deposit moisture content ({phi}timesS). These may be effectively utilized for the examination of timbering and measures against gushing water. Work records for a 500m section in the S point water channel tunnel are compared with the results of conversion, and it is found that there is rough agreement between the two. 8 figs., 1 tab.

  12. Strain Accommodation By Facile WO6 Octahedral Distortion and Tilting During WO3 Heteroepitaxy on SrTiO3(001)

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yingge; Gu, Meng; Varga, Tamas; Wang, Chong M.; Bowden, Mark E.; Chambers, Scott A.

    2014-08-27

    In this paper, we show that compared to other BO6 octahedra in ABO3 structured perovskite oxides, the WO6 octahedra in tungsten trioxide (WO3) can withstand a much larger degree of distortion and tilting to accommodate interfacial strain, which in turn strongly impact the nucleation, structure, and defect formation during the epitaxial growth of WO3 on SrTiO3(001). A meta-stable tetragonal phase can be stabilized by epitaxy and a thickness dependent phase transition (tetragonal to monoclinic) is observed. In contrast to misfit dislocations to accommodate the interfacial stain, the facial WO6 octahedral distortion and tilting give rise to three types of planar defects that affect more than 15 monolayers from the interface. These atomically resolved, unusual interfacial defects may significantly alter the electronic, electrochromic, and mechanical properties of the epitaxial films.

  13. Characterization of MAPLE deposited WO3 thin films for electrochromic applications

    Science.gov (United States)

    Boyadjiev, S. I.; Stefan, N.; Szilágyi, I. M.; Mihailescu, N.; Visan, A.; Mihailescu, I. N.; Stan, G. E.; Besleaga, C.; Iliev, M. T.; Gesheva, K. A.

    2017-01-01

    Tungsten trioxide (WO3) is a widely studied material for electrochromic applications. The structure, morphology and optical properties of WO3 thin films, grown by matrix assisted pulsed laser evaporation (MAPLE) from monoclinic WO3 nano-sized particles, were investigated for their possible application as electrochromic layers. A KrF* excimer (λ=248 nm, ζFWHM=25 ns) laser source was used in all experiments. The MAPLE deposited WO3 thin films were studied by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD) and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetry measurements were also performed, and the coloring and bleaching were observed. The morpho-structural investigations disclosed the synthesis of single-phase monoclinic WO3 films consisting of crystalline nano-grains embedded in an amorphous matrix. All thin films showed good electrochromic properties, thus validating application of the MAPLE deposition technique for the further development of electrochromic devices.

  14. WO3-reduced graphene oxide composites with enhanced charge transfer for photoelectrochemical conversion.

    Science.gov (United States)

    Wu, Haoyu; Xu, Ming; Da, Peimei; Li, Wenjie; Jia, Dingsi; Zheng, Gengfeng

    2013-10-14

    Hybrid structures between semiconducting metal oxides and carbon with rational synthesis represent unique device building blocks to optimize the light absorption and charge transfer process for the photoelectrochemical conversion. Here we demonstrate the realization of a WO3-reduced graphene oxide (RGO) nanocomposite via hydrothermal growth of ultrathin WO3 nanoplates directly on fluorine-doped tin oxide (FTO) substrates, followed by in situ photo-reduction to deposit RGO layers on WO3 nanoplate surface. Photoanodes made of the WO3-RGO nanocomposites have achieved a photocurrent density of 2.0 mA cm(-2) at 1.23 V vs. reversible hydrogen electrode (RHE), which is among the highest reported values for photoanodes based on hydrothermally grown WO3. Electrochemical impedance spectroscopy reveals that the increase of photoactivity is attributed to the enhanced charge transfer by the incorporation of RGO, thus suggesting a general approach for designing other metal oxide-RGO hybrid architectures.

  15. Optical Properties of LiIn(1−Tm(WO42 Blue Phosphor

    Directory of Open Access Journals (Sweden)

    Mourad Derbal

    2009-01-01

    Full Text Available LiIn1−Tm(WO42 (=0, 0.5, 1, 5, and 10 at.% polycrystalline powders blue phosphors were prepared via the classical solid-state reaction method. X-ray diffraction (XRD, scanning electron microscope (SEM, photoluminescence excitation, and emission spectra were used to characterize LiIn1−Tm(WO42 phosphors. By analyzing the excitation and emission spectra of LiIn1−Tm(WO42 samples, the result indicates that there exists the energy transfer only from the WO42− group to the 1G4 energy level of Tm3+ ion. On the other hand, the influence of the thulium concentration on the blue emission transition 1D2→3F4 and 1G4→3H6 and the emission of WO42− group are investigated.

  16. Hydrothermal Synthesis of WO3 Nanowires in the Presence of Guanidine Sulfate and Its Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    MU Wanjun; YU Qianhong; LI Xingliang; WEI Hongyuan; JIAN Yuan

    2016-01-01

    WO3 nanowires were fabricated by a hydrothermal method, which proceeded at 170℃ for 48 h in a solution containing C2H10N6H2SO4 as a dispersant and Na2WO4 as a starting material. The nanowires exhibit a well crystallized one-dimensional structure with 20 nm in diameter and several microns in length. The physicochemical properties of WO3 were compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and UV-vis spectroscopy (UV-Vis). The photoactivity of the as-perpared WO3 nanowires was evaluated through the photodegradation of methylene blue (MB) in aqueous solution. The experimental results demonstrate that addition of C2H10N6H2SO4 salt in the WO3 nanowires synthesis process can enhance its photocatalytic activity obviously.

  17. MWCNT/WO{sub 3} nanocomposite photoanode for visible light induced water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Yousefzadeh, Samira [Physics Department, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Reyhani, Ali [Physics Department, Faculty of Science, Imam Khomeini International University, P.O. Box 34149-16818, Qazvin (Iran, Islamic Republic of); Naseri, Naimeh [Physics Department, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Moshfegh, Alireza Z., E-mail: moshfegh@sharif.edu [Physics Department, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran (Iran, Islamic Republic of)

    2013-08-15

    The Multi-walled carbon nanotube (MWCNT)/WO{sub 3} nanocomposite thin films with different MWCNT’s weight percentages were prepared by sol–gel method as visible light induced photoanode in water splitting reaction. Weight percentage of MWCNT in the all nanocomposite thin films was confirmed by TGA/DSC analysis. According to XPS analysis, oxygenated groups at the surface of the MWCNT and stoichiometric formation of WO{sub 3} thin films were determined, while the crystalline structure of the nanocomposite samples was studied by XRD indicating (0 0 2) peak of MWCNT in the monoclinic phase of WO{sub 3}. The influence of different weight percentage (wt%) of MWCNT on WO{sub 3} photoactivity showed that the electron conductivity, charge transfer and electron life time had improved as compared with the pure WO{sub 3}. Based on linear sweep voltammetry and chronoamperometry measurements, the (1 wt%) MWCNT/WO{sub 3} nanocomposite thin films photoanode has a maximum photocurrent density of ∼4.5 A/m{sup 2} and electron life time of about 57 s. - Graphical abstract: Photocurrent density versus time at constant potential (0.7 V) for the WO{sub 3} films containing different MWCNT weight percentages annealed at 400 °C under 1000 Wm{sup −2} visible photo-illumination. Display Omitted - Highlights: • MWCNT/ WO{sub 3} nanocomposite thin films were synthesized using sol–gel derived method. • TGA/DSC confirmed the weight percentage of MWCNT in the all nanocomposite thin films. • XPS analysis revealed that WO{sub 3} was attached on the oxygenated group of MWCNT surface. • The Highest Photoelectrochemical activity is achieved for (1 wt%)MWCNT/WO{sub 3} thin film.

  18. Charged particle response of PbWO sub 4

    CERN Document Server

    Hoek, M; Hejny, V; Löhner, H; Metag, V; Novotny, R; Wörtche, H J

    2002-01-01

    The response of PbWO sub 4 to high-energy protons has been investigated in two test experiments at the proton facilities COSY and AGOR. The determined energy resolution below 360 MeV of sigma/E=1.44%/E subgamma sup 1 sup / sup 2 +1.97% is comparable to the known photon response. Measured spectra of inelastically scattered protons below 85 MeV are even compared to similar distributions obtained for BaF sub 2 - and CeF sub 3 -detectors.

  19. Photoinduced (WO4)3--La3+ center in PbWO4: Electron spin resonance and thermally stimulated luminescence study

    Science.gov (United States)

    Laguta, V. V.; Martini, M.; Meinardi, F.; Vedda, A.; Hofstaetter, A.; Meyer, B. K.; Nikl, M.; Mihóková, E.; Rosa, J.; Usuki, Y.

    2000-10-01

    The localization of electrons at W6+ sites perturbed by lanthanum in PbWO4 is studied by electron spin resonance (ESR) and thermally stimulated luminescence (TSL) measurements. The (WO4)3--La3+ centers are created at the W6+ sites close to La3+ in two different ways: (i) direct trapping of electrons from the conduction band under ultraviolet or x-ray irradiation at T=60 K (ii) retrapping of electrons freed from unperturbed (WO4)3- centers after irradiation at Teffect, which gives rise to a rhombic distortion of (WO4)3- complex. At T~95-98 K the (WO4)3--La3+ centers are thermally ionized giving rise to a TSL glow peak due to the recombination of detrapped electrons with localized holes. The emission spectrum of the TSL features one band peaking at 2.8 eV. The temperature dependence of both TSL and ESR intensity is analyzed in the frame of a general order recombination model. The thermal ionization energy of (WO4)3--La3+ centers has been calculated to be approximately 0.27 eV.

  20. Hydrothermal synthesis of FeWO{sub 4}-graphene composites and their photocatalytic activities under visible light

    Energy Technology Data Exchange (ETDEWEB)

    He, Gang-Ling; Chen, Ming-Jie; Liu, You-Qin; Li, Xin; Liu, Ying-Ju; Xu, Yue-Hua, E-mail: xuyuehua@scau.edu.cn

    2015-10-01

    Graphical abstract: - Highlights: • FeWO{sub 4}-RGO composites were hydrothermally fabricated by facile one-step method. • FeWO{sub 4}-RGO and FeWO{sub 4} had a similar particle size, in the range of 30–50 nm. • High efficiency for photocatalytic degradation of RhB was exhibited by FeWO{sub 4}-RGO. • FeWO{sub 4}-xRGO showed higher photocatalytic activities than pure FeWO{sub 4}. • The electron–hole pairs can be effectively separated due to RGO coupling. - Abstract: Monoclinic ferberite FeWO{sub 4}-reduced graphene oxide (FeWO{sub 4}-RGO) composites were hydrothermally fabricated by facile one-pot method in situ reduction of graphene oxide. As-prepared FeWO{sub 4}-RGO photocatalysts were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and diffuse reflectance spectra (DRS). The FeWO{sub 4}-RGO photocatalysts and pure FeWO{sub 4} photocatalyst had a similar particle size, which was in the range of 30–50 nm. FeWO{sub 4} and FeWO{sub 4}-RGO photocatalysts showed absorption in the visible region, and the band gap energy of FeWO{sub 4} decreased slightly after RGO coupling. FeWO{sub 4}-RGO photocatalysts exhibited high efficiencies in photocatalytic degradation of dye pollutant Rhodamine B (RhB) in solution under visible light irradiation (a 4 W Light Emitting Diode lamp). All FeWO{sub 4}-RGO photocatalysts under visible light showed higher photocatalytic activities than pure FeWO{sub 4} photocatalyst, and FeWO{sub 4}-0.3RGO showed the best photocatalytic activity. The FeWO{sub 4}-RGO composites were formed through the chemical contact between nanometer FeWO{sub 4} particles and RGO, and RGO could act as a good electron acceptor. The enhancement in visible-light photocatalytic performance may be mainly attributed to the effective separation of the photogenerated electron–hole pairs.

  1. Hydrothermal synthesis and studies on photochromic properties of Al doped WO{sub 3} powder

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yi, E-mail: sysy7373@163.com; Yan, Peng; Yang, Yali; Hu, Fengping; Xiao, Yilin; Pan, Li; Li, Zhen

    2015-04-25

    Graphical abstract: Pure and aluminum (Al) doped WO{sub 3} were synthesized via a facile hydrothermal process. The XPS peaks indicated that the powders contained W, Al, O, means the Al ions as the dopant were successfully incorporated into the crystal lattice of WO{sub 3} even though it had a great different valence state with W{sup 6+}. Compared with pure WO{sub 3}, the binding energies of W4f of Al-doped WO{sub 3} was much lower, suggesting the presence of W{sup 5+} species, which induced a transition band to decrease the band gap of WO{sub 3}. Urchin-like morphology WO{sub 3} had a special microstructure and large specific surface area of the powder. The result that Al-doped WO{sub 3} exhibited superior photochromic performance might own to the narrower band gap of WO{sub 3} and urchin-like morphology. - Highlights: • All of the WO{sub 3} powder were synthesized by a facile hydrothermal deposition process. • Al ions as the dopant were successfully incorporated into the crystal lattice of WO{sub 3}. • The Al doping made the powder had an outstanding photochromic properties. • The mechanism for the improved photochromic performances of the powder was proposed. - Abstract: A series of pure and aluminum (Al) doped WO{sub 3} powders were synthesized at low temperature. The as synthesized materials have been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–VIS) spectroscopy and color difference meter, respectively. A relation was found between the color difference and the UV–VIS photochromic activity. Moreover, the optical band gap of the as-prepared powder narrowed due to the appearance of impurity levels as the Al{sup 3+} ions migrated into the WO{sub 3} crystal lattice. Some rod-like particles have been found to decrease with the increase of Al concentration. An optimum Al concentration was found to be 0.25% to present the best UV-light induced photochromic activity. The mechanism of

  2. Subsolidus Phase Relations of the CaO-WO3-CuO System at 800 °C in Air

    DEFF Research Database (Denmark)

    Grivel, J. -C.

    2012-01-01

    The subsolidus phase relations of the CaO-WO3-CuO system were investigated in air. The samples were equilibrated at 800 degrees C. Under these conditions, five binary oxide phases are stable: Ca2CuO3, Cu3WO6, CuWO4, CaWO4 and Ca3WO6. The pseudo-ternary section is characterised by 6 three-phase re......The subsolidus phase relations of the CaO-WO3-CuO system were investigated in air. The samples were equilibrated at 800 degrees C. Under these conditions, five binary oxide phases are stable: Ca2CuO3, Cu3WO6, CuWO4, CaWO4 and Ca3WO6. The pseudo-ternary section is characterised by 6 three...

  3. Mixed conductor anodes: Ni as electrocatalyst for hydrogen conversion

    DEFF Research Database (Denmark)

    Primdahl, S.; Mogensen, Mogens Bjerg

    2002-01-01

    Five types of anodes for solid oxide fuel cells (SOFC) are examined on an yttria-stabilised zirconia (YSZ) electrolyte by impedance spectroscopy at 850 degreesC in hydrogen. The examined porous anodes are a Ni/Zr(0.92)Y(0.16)O(2.08) (Ni/YSZ) cermet, a Ni/Ce(0.9)Gd(0.1)O(1.95) (Ni/CGI) cermet, a Ce......(0.6)Gd(0.4)O(1.8) (CG4) ceramic, a La(0.75)Sr(0.25)Cr(0.97)V(0.03)O(3) (LSCV) ceramic and a Ti(0.22) Y(0.16)Zr(0.92)O(2.52) (TiYSZ) ceramic, Addition of small amounts ( approximate to I w/o) of Ni to the electrode surface is found to improve electrode performance on mixed electronic and ionic...... conductors (MIEC's), distinctly in the low-frequency part of the impedance spectra. An effect of isotope exchange (H(2)/H(2)O to D(2)/D(2)O) is observed for all anodes. The low-frequency limitation is suggested to be hydrogen adsorption and/or dissociation on the surface of MIEC electrodes, (C) 2002 Elsevier...

  4. Electrochromic Characterization of Electrodeposited WO3 Thin Films

    Science.gov (United States)

    Vijayalakshmi, R.; Jayachandran, M.; Sanjeeviraja, C.

    2002-12-01

    The electrochromic properties of certain transition metal oxides have been studied for several years resulting in commercial films are deposited as thin layers (0.1 to 0.4 microns) onto a transparent conductive automotive mirror and sun-glass products. The largest potential application of electrochromics is in window to regulate heat and light flow. Fabrication cost is one of the greatest barriers for large area development of the smart windows. Tungsten trioxide (WO3) can be colored deeply in with an optical irradiation of appropriate energy (photochromism) or with an applied electric field (electrochromism). These processes have received considerable attention because of their potential application in electrochromic windows, display devices, sensors, and so on. For these purposes, tungsten trioxide films prepared by various physical methods such as molecular beam epitaxy, CVD, etc have been reported. These methods are generally expensive and it is difficult to form large area films. However electrodeposition method is probably most economical method for making the films in addition to its relative ease in forming in large area films. In this paper, tungsten trioxide (WO3) films are prepared through the electrodeposition route and these films are used to study the electrochromic behavior in the various electrolytes by changing the concentrations. When coloration, the film attains deep blue color and in reduced state it becomes colorless. After the ion intercalation, the optical properties are also studied in the UV-Vis-NIR region.

  5. The growth of Nd:CaWO4 single crystals

    Directory of Open Access Journals (Sweden)

    ALEKSANDAR GOLUBOVIC

    2003-12-01

    Full Text Available CaWO4 doped with 0.8 % at. Nd (Nd:CaWO4 single crystals were grown from the melt in air by the Czochralski technique. The critical diameter dc = 1.0 cm and the critical rate of rotation wc = 30 rpm were calculated from hydrodynamic equations for buoyancy-driven and forced convection. The rate of crystal growth was experimentally obtained to be 6.7 mm/h. For chemical polishing, a solution of 1 part saturated chromic acid (CrO3 in water and 3 parts conc. H3PO4 (85 % at 433 K with an exposure time of 2 h was found to be adequate. A mixture of 1 part concentrated HF and 2 parts chromic acid at room temperature after exposure for 30 min was found to be a suitable etching solution. The lattice parameters a = 0.52404 (6 nm, c = 1.1362 (6 nm and V0 = 0.312 (2 nm3 were determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.

  6. Preparation, structures and photoluminescent enhancement of CdWO 4-TiO 2 composite nanofilms

    Science.gov (United States)

    Jia, Runping; Zhang, Guoxin; Wu, Qingsheng; Ding, Yaping

    2006-12-01

    For the first time, Cadmium tungstate (CdWO4)-TiO2 composite nanofilms on a glass substrate were prepared by means of the dip-coating technique, in which collodion was used as a dispersant and film-forming agent. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo gravimetric and thermal analyses (TG/DTA), FTIR and photoluminescence (PL) methods, respectively. SEM and XRD characterization of these films indicated that CdWO4 particles crystallized in a monoclinic wolframite-type structure whereas TiO2 particles were Anatase phase; and both of them were well distributed in the nanofilms. FTIR spectra proved the presence of CdWO4 on the nanofilms. Photoluminescent results showed that the emitting peak of CdWO4 films blue shifted slightly relative to that of CdWO4 crystal. Moreover, the PL intensity of CdWO4-TiO2 composite nanofilm was much higher than that of CdWO4 nanofilm. We ascribed that the introduction of TiO2 should be responsible for the PL enhancement.

  7. High-Tc superconductivity in nanostructured NaxWO3-y: Sol-gel route

    Science.gov (United States)

    Aliev, Ali

    2009-03-01

    Tungsten trioxide, WO3-y infiltrated into various nanoporous matrix structures such as carbon inverse opal, carbon nanotubes paper, or platinum sponge and then intercalated with alkaline ions (Li^+, Na^+) exhibits a pronounced diamagnetic onset in ZFC magnetization in a wide range of temperatures, 125-132 K. Resistivity measurements show non zero jump and intensive fluctuations of electrical resistance below observed transition points. The observed magnetic and electrical anomalies in nanostructured tungsten bronzes (LixWO3-y, NaxWO3-y) suggest the possibility of localized non-percolated superconductivity. The direct evidence of polaron formation from temperature dependence of EPR and photoemission spectra and formation of bipolarons in weakly reduced to WO3-y, with 3-y typically in the order of 2.95 suggest bipolarons mechanism of a Bose-Einstein condensation of trapped electron pairs in doped WO3-y. On the other hand the strong lattice instabilities in 2D systems like layered cuprates and tungsten bronzes place the upper limit on Tc. Than, the percolative self-organized mechanism on the metal/insulator interface like Na/WO3 and NaWO3/nanostructured matrix can facilitate the high Tc obtained in sodium bronzes infiltrated into inverted carbon opal or carbon nanotube matricies.

  8. Synthesis of WO{sub 3} flower-like hierarchical architectures and their sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Dan; Wang, Guosheng; San, Xiaoguang [College of Chemical Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); Song, Yinmin [College of Chemical Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Shen, Yanbai, E-mail: shenyanbai@mail.neu.edu.cn [College of Resources and Civil Engineering, Northeastern University, Shenyang 110819 (China); Zhang, Yajing; Wang, Kangjun [College of Chemical Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); Meng, Fanli, E-mail: flmeng@iim.ac.cn [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China)

    2015-11-15

    WO{sub 3} flower-like hierarchical architectures were synthesized by hydrothermal process using sodium tungstate (Na{sub 2}WO{sub 4}·2H{sub 2}O) as tungsten source and citric acid (CA) as an assistant agent. The morphology and crystal structure were investigated using scanning electron microscope and X-ray diffractometer. It is found that CA played a significant role in governing morphologies of product during hydrothermal process. The obtained products were identified as triclinic crystal WO{sub 3} structure. The ethanol gas sensing measurements showed that well-defined WO{sub 3} flower-like structures synthesized at CA/W molar ratio of 1 with large specific surface area exhibited the higher responses compared with others at all operating temperatures. Moreover, the reversible and fast response to ethanol gas at various gas concentrations and good selectivity were obtained. The results indicated that the WO{sub 3} flower-like hierarchical architectures are promising materials for gas sensors. - Highlights: • WO{sub 3} flower-like structures were successfully synthesized by hydrothermal method. • The effect of citric acid amount on morphologies was investigated. • Good ethanol gas sensing properties of WO{sub 3} flower-like structures were obtained.

  9. Gas sensing properties of graphene–WO{sub 3} composites prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Xiangfeng, E-mail: xfchu99@ahut.edu.cn [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002 (China); Hu, Tao [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002 (China); Gao, Feng [Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Dong, Yongping; Sun, Wenqi; Bai, Linshan [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002 (China)

    2015-03-15

    Graphical abstract: - Highlights: • The amount of graphene had an effect on the morphology of graphene–WO{sub 3} composites. • The optimum temperature of 0.1 wt% graphene–WO{sub 3} sensor to acetaldehyde was 100 °C. • 0.1 wt% graphene–WO{sub 3} sensor exhibited good selectivity to acetaldehyde at 100 °C. - Abstract: Graphene–WO{sub 3} composites mixed with different amounts of graphene (0, 0.1, 0.5, 1 and 3 wt%) were prepared by hydrothermal method at 180 °C for 24 h. The as-prepared graphite oxide, graphene and graphene–WO{sub 3} composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR) and Raman spectroscopy, respectively. The effect of the amount of graphene in the composites on the gas-sensing responses and the gas-sensing selectivity of the materials was investigated. The experimental results revealed that the sensor based on 0.1 wt% graphene–WO{sub 3} composite exhibited high response and good selectivity to acetaldehyde vapor at 100 °C, the optimum operating temperature of this sensor to 1000 ppm acetaldehyde vapor decreased from 180 °C to 100 °C comparing with that of pure WO{sub 3}. The response time and the recovery time for 100 ppm acetaldehyde vapor were 250 s and 225 s, respectively.

  10. WO3 nanorolls self-assembled as thin films by hydrothermal synthesis

    Science.gov (United States)

    Vankova, S.; Zanarini, S.; Amici, J.; Cámara, F.; Arletti, R.; Bodoardo, S.; Penazzi, N.

    2015-04-01

    We report a novel type of WO3 nanostructure, i.e. nanorolls obtained as a self-assembled thin film on a transparent conductive substrate. The mild conditions of preparation, avoiding the use of HCl, result in an eco-friendly hydrothermal method with reduced crystallization time. FESEM and HR-TEM show that WO3 nanocrystals are made of rolled nanoflakes with a telescope-like appearance at their tip. For their nano-porosity, electrochemical accessibility, good adhesion to substrates and the envisaged presence of nanocavities between the WO3 layers, these materials hold tremendous promise in nano-electronics, electrochromic devices, water photo-splitting cells, Li-ion batteries and nano-templated filters for UV radiation.We report a novel type of WO3 nanostructure, i.e. nanorolls obtained as a self-assembled thin film on a transparent conductive substrate. The mild conditions of preparation, avoiding the use of HCl, result in an eco-friendly hydrothermal method with reduced crystallization time. FESEM and HR-TEM show that WO3 nanocrystals are made of rolled nanoflakes with a telescope-like appearance at their tip. For their nano-porosity, electrochemical accessibility, good adhesion to substrates and the envisaged presence of nanocavities between the WO3 layers, these materials hold tremendous promise in nano-electronics, electrochromic devices, water photo-splitting cells, Li-ion batteries and nano-templated filters for UV radiation. Electronic supplementary information (ESI) available: Characterization techniques; additional FESEM micrographs; typical XRD pattern of WO3 nanoroll thin film; typical Nyquist plots at ambient temperature; indicative diameter and length of WO3 NR by varying the PVA chain length; effect of 2000 cycles of electrochemical switching on the STB, STC and ΔT% coloration efficiency of the WO3 NR. See DOI: 10.1039/c4nr07290a

  11. Dual preparation of hydrophobic and hydrophilic BaWO{sub 4}:Eu phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young-Sik; Huh, Young-Duk, E-mail: ydhuh@dankook.ac.kr

    2016-06-15

    Highlights: • Red-emitting BaWO{sub 4}:Eu phosphors were prepared in hexane-water bilayer system. • The hydrophobic nanometer-sized BaWO{sub 4}:Eu phosphors were obtained in hexane. • The hydrophilic micrometer-sized BaWO{sub 4}:Eu dendrites were obtained in water. - Abstract: BaWO{sub 4}:Eu phosphors were prepared by performing a solvothermal reaction in a water–hexane bilayer system. A barium oleate (and europium oleate) complex was obtained in hexane via a phase transfer reaction involving Ba{sup 2+} (and Eu{sup 3+}) ions in an aqueous solution of sodium oleate. The outer surfaces of the nanometer-sized BaWO{sub 4}:Eu phosphors were capped by the long alkyl chain of oleate; therefore, the hydrophobic nanometer-sized BaWO{sub 4}:Eu phosphors preferentially dissolved in the hexane layer. The micrometer-sized BaWO{sub 4}:Eu phosphors were obtained in the water layer. The BaWO{sub 4}:Eu phosphors prepared in hexane and water yielded sharp strong absorption and emission peaks at 464 and 615 nm, respectively, due to the {sup 7}F{sub 0} → {sup 5}D{sub 2} and the {sup 5}D{sub 0} →{sup 7} F{sub 2} transitions of the Eu{sup 3+} ions. The BaWO{sub 4}:Eu phosphors are good candidate red-emitting phosphors for use in InGaN blue-emitting diodes, which have an emission wavelength of 465 nm.

  12. 负载金属对WO3-TiO2光催化剂结构与催化性能的影响%Effects of Loaded Metal on Structure and Photocatalytic Performance of Photocatalyst for Synthesis of MAA from Propylene with Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    梅长松; 钟顺和

    2005-01-01

    用溶胶-凝胶和浸渍-还原相结合的方法制得M/WO3-TiO2(M=Pd,Cu,Ni,Ag)光催化剂.利用X射线衍射(XRD)、程序升温还原(TPR)、红外(IR)、程序升温脱附(TPD)、紫外-可见漫反射光谱(UV-Vis-DRS)和光反应器等技术研究了复合半导体负载金属的物相结构、光吸收性能和光催化反应性能.结果表明:金属负载在复合半导体上延迟了TiO2由锐钛矿向金红石相转化,增强W与载体TiO2的相互作用,使TiO2光吸收限发生蓝移,对可见光部分的吸收明显增加;固体材料吸光性能强弱顺序Pd/WO3-TiO2 Cu/WO3-TiO2>Ag/WO3-TiO2>Ni/WO3-TiO2;金属Pd对CO2吸附能力过强,卧式吸附态脱附温度高,光催化效率不高;金属Cu对CO2吸附能力适中,CO2与C3H6脱附温度较接近,实现了"光-表面-热"协同作用,光量子效率最高,达到19.7%.

  13. High efficiency tandem organic light-emitting devices with Al/WO3/Au interconnecting layer

    OpenAIRE

    2007-01-01

    An interconnecting layer of Al (2 nm)/WO3 (3 nm)/Au (16 nm) was studied for application in tandem organic light-emitting devices. It can be seen that the Al/WO3/Au structure plays the role of an excellent interconnecting layer. The introduction of WO3 in the connection unit significantly improves the device efficiency as compared to the case of Al/Au. Thus, the current efficiency of the two-unit tandem devices is enhanced by two factors with respect to the one-unit devices. The green two-u...

  14. CTAB-assisted ultrasonic synthesis, characterization and photocatalytic properties of WO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Martínez, D., E-mail: dansanm@gmail.com; Gomez-Solis, C.; Torres-Martinez, Leticia M.

    2015-01-15

    Highlights: • WO{sub 3} 2D nanostructures were synthesized by ultrasound method assisted with CTAB. • WO{sub 3} morphology was mainly of rectangular nanoplates with a thickness of ∼50 nm. • The highest surface area value of WO{sub 3} was obtained to lowest concentration of CTAB. • WO{sub 3} activity was attributed to morphology, surface area and the addition of CTAB. • WO{sub 3} nanoplates were able to causing almost complete mineralization of rhB and IC. - Abstract: WO{sub 3} 2D nanostructures have been prepared by ultrasound synthesis method assisted with CTAB using different molar ratios. The formation of monoclinic crystal structure of WO{sub 3} was confirmed by X-ray powder diffraction (XRD). The characterization of the WO{sub 3} samples was complemented by analysis of scanning electron microscopy (SEM), which revealed morphology mainly of rectangular nanoplates with a thickness of around 50 nm and length of 100–500 nm. Infrared spectroscopy (FT-IR) was used to confirm the elimination of the CTAB in the synthesized samples. The specific surface area was determinate by the BET method and by means of diffuse reflectance spectroscopy (DRS) it was determinate the band-gap energy (E{sub g}) of the WO{sub 3} samples. The photocatalytic activity of the WO{sub 3} oxide was evaluated in the degradation reactions of rhodamine B (rhB) and indigo carmine (IC) under Xenon lamp irradiation. The highest photocatalytic activity was observed in the samples containing low concentration of CTAB with morphology of rectangular nanoplates and with higher surface area value than commercial WO{sub 3}. Photodegradation of rhB and IC were followed by means of UV–vis absorption spectra. The mineralization degree of organic dyes by WO{sub 3} photocatalyst was determined by total organic carbon analysis (TOC) reaching percentages of mineralization of 92% for rhB and 50% for IC after 96 h of lamp irradiation.

  15. Ab-initio density functional theory study of a WO3 NH3-sensing mechanism

    Institute of Scientific and Technical Information of China (English)

    Hu Ming; Zhang Jie; Wang Wei-Dan; Qin Yu-Xiang

    2011-01-01

    WO3 bulk and various surfaces are studied by an ab-initio density functional theory technique.The band structures and electronic density states of WO3 bulk are investigated.The surface energies of different WO3 surfaces are compared and then the(002)surface with minimum energy is computed for its NH3 sensing mechanism which explains the results in the experiments.Three adsorption sites are considered.According to the comparisons of the energy and the charge change between before and after adsorption in the optimal adsorption site O1c,the NH3 sensing mechanism is obtained.

  16. Synthesis of WC powder through microwave heating of WO3-C mixture

    Science.gov (United States)

    Behnami, Amir Karimzadeh; Hoseinpur, Arman; Sakaki, Masoud; Bafghi, Mohammad Sh.; Yanagisawa, Kazumichi

    2017-02-01

    A simple, easy, and low-cost process for the fabrication of tungsten carbide (WC) powder through microwave heating of WO3-C mixtures was developed. Thermodynamic calculations and experimental investigations were carried out for WO3-C and W-C systems, and a formation mechanism was proposed. In the results, for the synthesis of WC, the use of over stoichiometric amount of C together with a specially assembled experimental setup (which effectively retains heat in the system) is necessary. The WC powder is successfully obtained by heating WO3:5C mixture for 900 s in a domestic microwave oven.

  17. Electrodeposition of WO3 nanoparticles into surface mounted metal-organic framework HKUST-1 thin films

    Science.gov (United States)

    Yoo, Hyeonseok; Welle, Alexander; Guo, Wei; Choi, Jinsub; Redel, Engelbert

    2017-03-01

    We describe a novel procedure to fabricate WO3@surface-mounted metal-organic framework (SURMOF) hybrid materials by electrodeposition of WO3 nanoparticles into HKUST-1, also termed Cu3(BTC)2 SURMOFs. These materials have been characterized using x-ray diffraction, time-of-flight secondary ion mass spectrometry, scanning electron microscopy, x-ray photoelectron spectroscopy as well as linear sweep voltammetry. The WO3 semiconductor/SURMOF heterostructures were further tested as hybrid electrodes in their performance for hydrogen evolution reaction from water.

  18. Ethanol vapour sensing properties of screen printed WO3 thick films

    Indian Academy of Sciences (India)

    R S Khadayate; R B Waghulde; M G Wankhede; J V Sali; P P Patil

    2007-04-01

    This paper presents ethanol vapour sensing properties of WO3 thick films. In this work, the WO3 thick films were prepared by standard screen-printing method. These films were characterized by X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM). The ethanol vapour sensing properties of these thick films were investigated at different operating temperatures and ethanol vapour concentrations. The WO3 thick films exhibit excellent ethanol vapour sensing properties with a maximum sensitivity of ∼1424.6% at 400°C in air atmosphere with fast response and recovery time.

  19. Nd3+:KGd(WO4)2激光晶体的研究%Study on Laser Crystal Nd3+:KGd(WO4)2

    Institute of Scientific and Technical Information of China (English)

    涂朝阳; J.J.ROmero; 等

    2001-01-01

    A series of KGd(WO4)2 powder samples with different Nd3+ doping concentrations were made and their fluorescent intensities at 1.06μm were measured.The optimal Nd3+ doping concentration has been determined.The liquid temperature curve for the system of Nd3+:KGd(WO4)2-K2WO4 was determined by means of differential thermal analysis(DTA),and large crystals of Nd3+:KGd(WO4)2 with dimensions of up to 50mm have been grown from a K2WO4 flux.From the grown crystal boule,a high-quality laser bulk crystal with dimensions of 5mm×5mm×6mm was cut out,and it's absorption spectrum has been measured.A laser output of 260mW at 1.06μm with a slope efficiency higher than 66% and a laser output of 135mW at 1.3μm with a slope efficiency up to 34.3% were obtained when this crystal was pumped by a Ti-sapphire laser.%合成了一系列不同Nd3+浓度掺杂的Nd3+:KGd(WO4)2粉末样品,进行了荧光光谱测试,初步确定了Nd3+的最佳掺杂浓度;测定了Nd3+:KGd(WO4)2-K2WO4生长体系的生长温度曲线,生长出尺寸达50mm的Nd3+:KGd(WO4)2优质激光晶体,切割出尺寸为5mm×5mm×6mm的优质激光器件,采用钛宝石模拟LD泵浦,在1.06μm处得到260mW的激光输出,斜率效率达到66%;在1.03μm处得到135mW激光输出,斜率效率达到34.3%。

  20. Photoreduction of non-noble metal Bi on the surface of Bi2WO6 for enhanced visible light photocatalysis

    Science.gov (United States)

    Zhang, Xiaojing; Yu, Shan; Liu, Yang; Zhang, Qian; Zhou, Ying

    2017-02-01

    In this report, Bi2WO6-Bi composite was prepared through an in situ photoreduction method and was characterized systematically by X-Ray diffraction, transmission electron microscopy, X-Ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The as-prepared Bi2WO6-Bi maintains the same crystal structure with the pristine Bi2WO6 regardless of some surface defects. Nevertheless, these surface defects result in the change of surface oxygen adsorption mode from hydroxyl to molecular oxygen on Bi2WO6. Photocatalytic activity over Bi2WO6-Bi is 2.4 times higher than that of Bi2WO6 towards the degradation of organic dye Rhodamine B (RhB) under visible light irradiation (λ > 420 nm). A deep study shows that cleavage of benzene ring is the main pathway for RhB degradation over Bi2WO6, but both the benzene cleavage and de-ethylation pathway coexist for RhB decomposition in the presence of Bi2WO6-Bi as the photocatalyst. Photoelectrochemical study including transient photocurrent tests and electrochemical impedance spectroscopy measurements shows that Bi2WO6-Bi could facilitate the charge transfer process compared to Bi2WO6. These data above has indicated a new insight into the promotion mechanism based on Bi related heterostructures.

  1. Preparation of WO3/g-C3N4 composites and their application in oxidative desulfurization

    Science.gov (United States)

    Zhao, Rongxiang; Li, Xiuping; Su, Jianxun; Gao, Xiaohan

    2017-01-01

    WO3/graphitic carbon nitride (g-C3N4) composites were successfully synthesized through direct calcining of a mixture of WO3 and g-C3N4 at 400 °C for 2 h. The WO3 was prepared by calcination of phosphotungstic acid at 550 °C for 4 h, and the g-C3N4 was obtained by calcination of melamine at 520 °C for 4 h. The WO3/g-C3N4 composites were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and Brunner-Emmett-Teller analysis (BET). The WO3/g-C3N4 composites exhibited stronger XRD peaks of WO3 and g-C3N4 than the WO3 and pure g-C3N4. In addition, two WO3 peaks at 25.7° and 26.6° emerged for the 36% -WO3/g-C3N4 composite. This finding indicated that WO3 was highly dispersed on the surface of the g-C3N4 nanosheets and interacted with the nanosheets, which resulted in the appearance of (012) and (022) planes of WO3. The WO3/g-C3N4 composite also exhibited a larger specific surface area and higher degree of crystallization than WO3 or pure g-C3N4, which resulted in high catalytic activity of the catalyst. Desulfurization experiments demonstrated that the desulfurization rate of dibenzothiophene (DBT) in model oil reached 91.2% under optimal conditions. Moreover, the activity of the catalyst was not significantly decreased after five recycles.

  2. Piezo-optic coefficients of CaWO4 crystals

    Science.gov (United States)

    Mytsyk, B. G.; Kost', Ya. P.; Demyanyshyn, N. M.; Andrushchak, A. S.; Solskii, I. M.

    2015-01-01

    All components of the piezo-optic coefficient matrix of calcium tungstate crystals, belonging to the 4/ m symmetry class, are determined. The reliability of the piezo-optic effect measurements in CaWO4 crystals is achieved by determining each piezo-optic coefficient from several experimental geometries and is also based on the correlation of the absolute piezo-electric coefficients and the path-difference coefficients. The rotation-shear diagonal coefficients π44 and π66 and three principal piezo-optic coefficients π11, π13, and π31 are refined by the polarization-optical method. It is confirmed that both the interferometric and polarization-optical methods should be used to study the piezo-optic effect with high accuracy. The results show that calcium tungstate is a promising material for acousto-optical and photoelastic modulation.

  3. Scheelite CaWO{sub 4} at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Grzechnik, Andrzej [Laboratory of Crystallography, University of Bayreuth, D-95440 Bayreuth (Germany); Crichton, Wilson A [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble cedex (France); Hanfland, Michael [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble cedex (France); Smaalen, Sander van [Laboratory of Crystallography, University of Bayreuth, D-95440 Bayreuth (Germany)

    2003-11-05

    The high-pressure room-temperature behaviour of scheelite CaWO{sub 4} (I4{sub 1}/a,Z = 4) is studied using high-resolution synchrotron angle-dispersive x-ray powder diffraction in diamond anvil cells loaded with helium or a mixture of methanol and ethanol as the pressure-transmitting media. At about 10 GPa, there occurs a phase transition to the fergusonite type (I 2/a,Z = 4) without any discontinuity in the pressure dependence of the unit cell volumes. These observations are discussed in relation to the high-pressure-high-temperature systematics of the AMX{sub 4} and AX{sub 2} type compounds.

  4. Effect of TiO2 Nanoparticles on Photochromism of WO3 Colloids

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    WO3 and TiO2 colloids were synthesized by the hydrolysis technique and part of the TiO2 colloid was treated by means of the hydrothermal method. The photochromic performances of the resulting materials obtained via combining the WO3 colloid with the treated TiO2 colloid and the non-treated TiO2 colloid, respectively, are very different. The TiO2 colloid without hydrothermal treatment can effectively improve the photochromic performance of the WO3 colloid. The TiO2 nanoparticles were investigated in detail by XRD, TEM, surface photovoltage spectra(SPS) and field-induced surface photovoltage spectrometry(FISPS). The photochromism mechanism of WO3 colloid is discussed.

  5. Hydrothermal Fabrication of WO3 Hierarchical Architectures: Structure, Growth and Response

    Directory of Open Access Journals (Sweden)

    Chuan-Sheng Wu

    2015-07-01

    Full Text Available Recently hierarchical architectures, consisting of two-dimensional (2D nanostructures, are of great interest for potential applications in energy and environmental. Here, novel rose-like WO3 hierarchical architectures were successfully synthesized via a facile hydrothermal method. The as-prepared WO3 hierarchical architectures were in fact assembled by numerous nanosheets with an average thickness of ~30 nm. We found that the oxalic acid played a significant role in governing morphologies of WO3 during hydrothermal process. Based on comparative studies, a possible formation mechanism was also proposed in detail. Furthermore, gas-sensing measurement showed that the well-defined 3D WO3 hierarchical architectures exhibited the excellent gas sensing properties towards CO.

  6. Synthesis of Bi2WO6 Microspheres with Visible-Light Photocatalytic Properties

    Science.gov (United States)

    Wan, Gengping; Wang, Guizhen

    2013-12-01

    Bi2WO6 microspheres constructed from nanosheets have been synthesized by a controllable solvothermal route in a large scale. The structure characterizations of the microspheres were investigated in detail by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). On the basis of XRD analysis and SEM observation of the products at different reaction time periods, a growth mechanism of Bi2WO6 microspheres was proposed. UV-Visible diffuse reflectance (DR) spectrum of the prepared Bi2WO6 microspheres demonstrates that they have absorption in the visible light region. The photocatalytic activity of Bi2WO6 microspheres toward Rhodamine-B (RhB) degradation was investigated and the as-prepared products exhibited good photocatalytic activity in degradation of RhB under 300 W Xe lamp light irradiation.

  7. Hydrothermal synthesis of Bi2WO6 hierarchical flowers with their photonic and photocatalytic properties

    Science.gov (United States)

    Dumrongrojthanath, Phattharanit; Thongtem, Titipun; Phuruangrat, Anukorn; Thongtem, Somchai

    2013-02-01

    Bi2WO6 hierarchical multi-layered flower-like assemblies were synthesized by a hydrothermal method at 180 °C for 24 h. XRD patterns were specified as pure orthorhombic well-crystallized Bi2WO6 phase. Their FTIR spectra show main absorption bands at 400-1000 cm-1, assigned as the stretching modes of the Bi-O and W-O, and W-O-W bridging stretching modes. SEM analysis shows that the product was 3D hierarchical flower-like assemblies, constructed by orderly arranged 2D layers of nanoplates. The UV-visible absorption shows an absorbance in the ultraviolet region with 3.4 eV band gap. Photocatalytic activity of Bi2WO6 hierarchical flowers was determined from the degradation of rhodamine-B by Xe light at 88% for 360 min irradiation.

  8. Photocatalytic Activity of Nanosized ZnWO4 Prepared by the Sol-gel Method

    Institute of Scientific and Technical Information of China (English)

    WU Yan; ZHANG Shi-cheng; ZHANG Li-wu; ZHU Yong-fa

    2007-01-01

    Nanosized ZnWO4 photocatalysts were successfully synthesized via the sol-gel process in a temperature range of 450-800 ℃. The grain size, crystal size, and crystallinity of ZnWO4 particles increased with the increase of calcination temperature and prolonging calcination time. The photocatalytic activity was measured for the degradation of an aqueous Rhodamine-B(RhB) solution and gaseous formaldehyde(FAD). With the increase of calcination temperature and time, the activities increased to a maximum and then decreased. ZnWO4 photocatalyst prepared at 550 ℃ for 10 h showed the highest activity, which is similar to the photocatalytic activity of P25TiO2 for the degradation of gaseous FAD. High crystallinity, large surface area, and good dispersion are responsible for the high photocatalytic performance of the prepared ZnWO4.

  9. Analysis of Publication Trends for DOE National Laboratories Comparisons using WoS and Scopus

    Energy Technology Data Exchange (ETDEWEB)

    Springer, Everett P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Milligan, Shelby [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-02

    This report describes: 1) how various laboratories compare in terms of peer-reviewed publications; how the numbers and trends compare between WoS and Scopus; and what research areas have grown or decreased.

  10. AOT-microemulsions-based formation and evolution of PbWO$_{4}$ crystals

    CERN Document Server

    Chen, D; Tang Kai Bin; Liang Zhen Hua; Zheng Hua Gui

    2004-01-01

    Anionic surfactant-AOT-microemulsions-assisted formation and evolution of PbWO//4 nanostructures with bundles rodlike, ellipsoidlike, and spherelike prepared at different media conditions were studied by powder X-ray diffraction pattern, field emission scanning electron microscopy, and transmission electron microscopy. The possible mechanisms for the formation of PbWO//4 samples in series of microemulsion systems were discussed. Various comparison experiments show that several experimental parameters, such as the AOT concentration, the water content, and reaction temperature play important roles in the morphological control of PbWO//4 nanostructures. Room-temperature photoluminescence of PbWO//4 samples with different morphologies has also been investigated and the results reveal that all these samples showed similar features with emissions at 480 similar to 510 nm but different luminescence intensity. 40 Refs.

  11. Bacteriophage WO Can Mediate Horizontal Gene Transfer in Endosymbiotic Wolbachia Genomes

    Science.gov (United States)

    Wang, Guan H.; Sun, Bao F.; Xiong, Tuan L.; Wang, Yan K.; Murfin, Kristen E.; Xiao, Jin H.; Huang, Da W.

    2016-01-01

    Phage-mediated horizontal gene transfer (HGT) is common in free-living bacteria, and many transferred genes can play a significant role in their new bacterial hosts. However, there are few reports concerning phage-mediated HGT in endosymbionts (obligate intracellular bacteria within animal or plant hosts), such as Wolbachia. The Wolbachia-infecting temperate phage WO can actively shift among Wolbachia genomes and has the potential to mediate HGT between Wolbachia strains. In the present study, we extend previous findings by validating that the phage WO can mediate transfer of non-phage genes. To do so, we utilized bioinformatic, phylogenetic, and molecular analyses based on all sequenced Wolbachia and phage WO genomes. Our results show that the phage WO can mediate HGT between Wolbachia strains, regardless of whether the transferred genes originate from Wolbachia or other unrelated bacteria. PMID:27965627

  12. [Doctor's degree thesis of Tomasz Adolf Wołkowiński "Carditidis rheumaticae historia"].

    Science.gov (United States)

    Stembrowicz, W

    2001-01-01

    In 1817 on the University of Vilnius Faculty of Medicine, T. A. Wołkowiński, a student of the eminent clinician Józef Frank, defended his doctor's degree thesis about a direct relation between rheumatic disease and cardiomegaly. It was probably the first paper in Poland describing with details the rheumatic heart disease. Unfortunately we don't know much about T. A. Wołkowiński's life.

  13. Facile and controlled synthesis of aligned WO3 nanorods and nanosheets as an efficient photocatalyst material

    Science.gov (United States)

    Ahmed, Bilal; Kumar, Sumeet; Ojha, Animesh K.; Donfack, P.; Materny, A.

    2017-03-01

    In this work, we have performed a facile and controlled synthesis of WO3 nanorods and sheets in different crystal phases (triclinic, orthorhombic and monoclinic) of WO3 using the sol-gel method. The detailed structures of the synthesized materials were examined by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy measurements. The shapes and crystal phases of the WO3 nanostructures were found to be highly dependent on the calcination temperature. The variation in crystalline phases and shapes is modified the electronic structure of the samples, which causes a variation in the value of optical band gap. The value of the Raman line intensity ratio I264/I320 has been successfully used to identify the structural transition from the triclinic to the orthorhombic phase of WO3. The PL spectra of the synthesized products excited at wavelengths 380, 400, and 420 nm exhibit intense emission peaks that cover the complete visible range (blue-green-red). The emission peaks at 460 and 486 nm were caused by the near band-edge and band to band transition, respectively. The peaks in spectral range 500-600 nm might be originated from the presence of oxygen vacancies lying within the energy band gap. The synthesized WO3 nanostructures showed improved photocatalytic activity for the photodegradation of MB dye. The enhanced photocatalytic activity of WO3 nanosheets compared to WO3 nanorods for photodegradation of methylene blue (MB) dye could be due to the shape of the nanostructured WO3. The sheet type of structure provides more active surface for the interaction of dye molecules compared to the rods, which results in a more efficient degradation of the dye molecules.

  14. Synthesis and evaluation of α-Ag2WO4 as novel antifungal agent

    Science.gov (United States)

    Foggi, Camila C.; Fabbro, Maria T.; Santos, Luís P. S.; de Santana, Yuri V. B.; Vergani, Carlos E.; Machado, Ana L.; Cordoncillo, Eloisa; Andrés, Juan; Longo, Elson

    2017-04-01

    Because of the need for new antifungal materials with greater potency, microcrystals of α-Ag2WO4, a complex metal oxide, have been synthetized by a simple co-precipitation method, and their antifungal activity against Candida albicans has been investigated. A theoretical model based on clusters that are building blocks of α-Ag2WO4 has been proposed to explain the experimental results.

  15. Photoelectrochemical solar cells based on Bi{sub 2}WO{sub 6}; Celdas solares fotoelectroquimicas basadas en Bi{sub 2}WO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Madriz, Lorean; Tata, Jose; Cuartas, Veronica; Cuellar, Alejandra; Vargas, Ronald, E-mail: lmadriz@usb.ve [Departamento de Quimica, Universidad Simon Bolivar, Caracas (Venezuela, Bolivarian Republic of)

    2014-04-15

    In this study, photoelectrochemical solar cells based on bismuth tungstate electrodes were evaluated. Bi{sub 2}WO{sub 6} was synthesized by a hydrothermal method and characterized by scanning electron microscopy, UV-Vis reflectance spectroscopy, and X-ray powder diffraction. For comparison, solar cells based on TiO{sub 2} semiconductor electrodes were evaluated. Photoelectrochemical response of Grätzel-type solar cells based on these semiconductors and their corresponding sensitization with two inexpensive phthalocyanines dyes were determined. Bi{sub 2}WO{sub 6}-based solar cells presented higher values of photocurrent and efficiency than those obtained with TiO{sub 2} electrodes, even without sensitization. These results portray solar cells based on Bi{sub 2}WO{sub 6} as promising devices for solar energy conversion owing to lower cost of production and ease of acquisition. (author)

  16. Effect of processed oils and fats on cholesterol metabolism. III. ; Comparison of the effects of palm oil, hardened soybean oil and cacao butter. Kako yushi no cholesterol taisha ni oyobosu eikyo. (3). ; Palm yu to koka daizuyu oyobi cacao abura tono eikyo no hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, C.; Chimi, K.; Kanematsu, H.; Niiya, I. (Japan Institute of Oils and Fats, Other Foods Inspection, Foundation, Tokyo (Japan)); Shimura, M. (Japan Margaruibe, Shortening and Lard Industries Association, Tokyo (Japan)); Mizutani, H. (Ueda Oils and Manufacturing Co. Ltd., Kobe (Japan)); Hirai, C. (Nihon University, Tokyo (Japan). College of Industrial Technology)

    1991-09-20

    Effects on cholesterol contained in serum lipids, levers and feces of rats and the metabolism were compared between palm oil, hardened soybean oil and cacao butter. In addition, the relations to the physical and chemical properties of these oils were also studied. In the case of cacao butter, saturated triglyceride of high fusing point was not contained at all and the main component is 2-oleo-1,3-disaturated glycerides. This component was the main cause for cacao butter to show the unique behavior. Concerning the cholesterol concentrations in lever, the hardened soybean oil group tended to be lower than other 3 groups and this tendency agreed approximately with that in serum. Cholesterol in the feces was also analyzed. Cholesteol content in the case of cacao butter was higher than those for the hardened soybean oil group and palm oil group, and much higher than that of the soybean oil group. But the lathosterol content did not show any significant difference compared with that of palm oil group, and the coprostanol content showed the lower value, which had the significant difference. 14 refs., 1 figs., 7 tabs.

  17. Report on the survey made under the research contract with NEDO, `The International Work Division/Energy Demand Effect Survey.`. Influence of the economic growth in Asia on the energy demand; 1996 nendo `kokusai suihei bungyo energy juyo eikyo chosa` itaku chosa kekka hokokusho. Asia no keizai hatten ga energy juyo ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This report includes surveys on the following: (1) the progress situation of the Asian information society, (2) changes of corporate network, business flow, material flow and money flow in association with the information society, (3) the present situation of the industry-accumulated region in Asia and inter-region network, (4) impacts of the above-mentioned changes on the trade and investment structure in Japan, (5) how to tackle the energy issue in Asia in the future. First, effects of the advance of the information society on energy supply/demand were studied. Next, an analysis was made of effects of the progress of the high-grade information society in Asia on economy, industry and corporate action. The degree of the progress of the information society in Asian countries was made clear from the infrastructure arrangement and the developmental status of application. Contribution of the financial network to the economic growth in Asia and the development were clarified. The organization of corporate networks in Asia where paradigms are converting was made clear to consider industrial clusters in Asia. Last, in the light of the economic relationship between Japan and Asia, a study was made on the future policy of Japan for Asia. 238 refs., 77 figs., 89 tabs.

  18. Modulating memristive performance of hexagonal WO3 nanowire by water-oxidized hydrogen ion implantation

    Science.gov (United States)

    Zhou, Yong; Peng, Yuehua; Yin, Yanling; Zhou, Fang; Liu, Chang; Ling, Jing; Lei, Le; Zhou, Weichang; Tang, Dongsheng

    2016-09-01

    In a two-terminal Au/hexagonal WO3 nanowire/Au device, ions drifting or carriers self-trapping under external electrical field will modulate the Schottky barriers between the nanowire and electrodes, and then result in memristive effect. When there are water molecules adsorbed on the surface of WO3 nanowire, hydrogen ions will generate near the positively-charged electrode and transport in the condensed water film, which will enhance the memristive performance characterized by analogic resistive switching remarkably. When the bias voltage is swept repeatedly under high relative humidity level, hydrogen ions will accumulate on the surface and then implant into the lattice of the WO3 nanowire, which leads to a transition from semiconducting WO3 nanowire to metallic HxWO3 nanowire. This insulator-metal transition can be realized more easily after enough electron-hole pairs being excited by laser illumination. The concentration of hydrogen ions in HxWO3 nanowire will decrease when the device is exposed to oxygen atmosphere or the bias voltage is swept in atmosphere with low relative humidity. By modulating the concentration of hydrogen ions, conductive hydrogen tungsten bronze filament might form or rupture near electrodes when the polarity of applied voltage changes, which will endow the device with memristive performance characterized by digital resistive switching.

  19. WO3/TiO2 nanotube photoanodes for solar water splitting with simultaneous wastewater treatment.

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, Karla Rosa; Robinson, David B.

    2013-05-01

    Nanostructured WO3/TiO2 nanotubes with properties that enhance solar photoconversion reactions were developed, characterized and tested. The TiO2 nanotubes were prepared by anodization of Ti foil, and WO3 was electrodeposited on top of the nanotubes. SEM images show that these materials have the same ordered structure as TiO2 nanotubes, with an external nanostructured WO3 layer. Diffuse reflectance spectra showed an increase in the visible absorption relative to bare TiO2 nanotubes, and in the UV absorption relative to bare WO3 films. Incident simulated solar photon-to-current efficiency increased from 30% (for bare WO3) to 50% (for WO3/TiO2 composites). With the addition of diverse organic pollutants, the photocurrent densities exhibited more than a 5-fold increase. Chemical oxygen demand measurements showed the simultaneous photodegradation of organic pollutants. The results of this work indicate that the unique structure and composition of these composite materials enhance the charge carrier transport and optical properties compared with the parent materials.

  20. Photoactivity enhancement of Zn-doped CdWO{sub 4} prepared with a hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Song, Xu Chun, E-mail: songxuchunfj@163.com [Department of Chemistry, Fujian Normal University, Fuzhou 350007 (China); Cui, Xia [Department of Chemistry, Fujian Normal University, Fuzhou 350007 (China); Huang, Wan Zhen [Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310014 (China); Zhang, Yong [Hangzhou Area Military Representative Office, Hangzhou, 310011 (China); Yin, Hao Yong [Institute of Environmental Science and Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Zheng, Yi Fan [Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310014 (China)

    2015-07-15

    Graphical abstract: - Highlights: • The zinc-doped CdWO{sub 4} photocatalyst was synthesized by a hydrothermal process. • The Zn-doped CdWO{sub 4} exhibited excellent photocatalytic efficiency. • Zinc effect on photocatalytic activity and photodegradation mechanism were investigated. - Abstract: The zinc-doped CdWO{sub 4} photocatalyst was successfully synthesized by a hydrothermal process. The influences of zinc doping on the phase structures, optical properties, morphologies and photocatalytic activities of the CdWO{sub 4} catalyst were investigated. The results showed that the zinc-doping can enhance the photocatalytic efficiency of CdWO{sub 4} with the highest activity obtained on the Zn-doped CdWO{sub 4} (Zn/Cd ratio of 0.1) for degradation of rhodamine B(RhB) under simulated solar light irradiation. The enhancement of photocatalytic activity may be attributed to the zinc doping which can change the band gap of the catalyst and subsequently inhibit the recombination of photogenerated electrons and holes.

  1. The Effect of Binarity and Metallicity in the Spectra of WC and WO Stars

    Directory of Open Access Journals (Sweden)

    L. Norci

    2002-01-01

    Full Text Available Se presenta el estudio estadístico de la intensidad (W, la relación y el ancho de algunas bandas de emisión de estrellas WC y WO, basado en un vasto conjunto de datos espectróscopicos. Se han obtenido valores medianos para cada tipo espectral. Se evidencia que en las estrellasWO yWC4 de la Galaxia, W(C IV 581 nm resulta ser menor que en estrellas extragalácticas. A su vez, el valor de W(O V 559 nm aumenta regularmente deWCL aWCE yWO, en las estrellas galácticas como en las extragalácticas. Suponemos que la variación de la estructura del viento estelar y de la metalicidad ambiental podrán ser la causa de las anomalías. El perfil de la banda a 465 nm evidencia, asimismo, que He II 468 nm es un componente importante en las clases WCE y WO. Se comenta también sobre las abundancias de carbono y el estado evolutivo de las estrellas WC y WO. De igual manera, se estima la relación de las intensidades del continuo OB/WR en estrellas binarias.

  2. Hydrogen sensing performance of WO3 thin film by using multi - wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    R. Ghasempour

    2014-04-01

    Full Text Available The WO3/MWNTs hybrid gas sensitive films were prepared by spin-coating on alumina substrate. The structure, morphology and chemical composition of the functionalized MWNTs and WO3/MWNTs hybrid films were studied by SEM, TEM, XRD, Raman, DLS and XPS methods. The MWCNT were initially functionalized (f-MWNTs. Dispersion and surface reactivity of MWNTs was improved because of oxygenate groups on MWNTs surface. Results showed WO3 nanoparticles were nucleated on oxygenated group on surface of f-MWNTs in hybrid suspension. After coating and annealing the films at 350 , the response of hybrid WO3/MWNTs films was measured. In addition, adding a little amount of MWNTs (the ratio of MWNTs/W less than 5/1000 wt% increased the hydrogen sensitivity so that the hybrid films showed an increase of 50 times compared to pure tungsten oxide layer in response to the 10000 ppm hydrogen concentration. Considering the results, the identification of these structures appear tobe 10 ppm hydrogen gas. With the addition of carbon nanotubes, the working temperature of pure tungsten oxide layers (400 reduced to 200 in hybrid layer. The gas sensitivity is suggested to have risendue to mainly the increase in the surface area as well as development of two types of depletion layers, one at the WO3/ MWNTs hetero junction and the other at WO3 grain boundaries.

  3. Highly sensitive and selective trimethylamine sensors based on WO3 nanorods decorated with Au nanoparticles

    Science.gov (United States)

    Liu, Lu; Song, Peng; Yang, Zhongxi; Wang, Qi

    2017-06-01

    One-dimensional tungsten oxide (WO3) gas sensing materials have been widely used for the detection of trimethylamine (TMA) gas. Furthermore, it is believed that an effective method to improve the gas sensing performance is to introduce noble metals into sensing materials. In this work, a novel gas sensing material was prepared by decorating Au nanoparticles on WO3 nanorods. Based on field emission scanning electron microscopy (FESEM/EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM), the morphology and microstructure of as-prepared samples were characterized. Results show that Au nanoparticles with diameter of 13-15 nm are loaded on the surface of WO3 nanorods with length of about 1-2 μm and width of 50-80 nm. Gas sensing tests reveal that the Au@WO3 sensor has remarkably enhanced response to TMA gas compared with pure WO3 nanorods. In addition, and the gas sensing mechanism has been investigated based on the experimental results. The superior sensing features indicate the present Au@WO3 nanocomposites are promising for gas sensors, which can be used in the detection of the trimethylamine gas and this work provides insights and strategies for the fabrication of sensing materials.

  4. Tungsten-based nanomaterials (WO{sub 3} & Bi{sub 2}WO{sub 6}): Modifications related to charge carrier transfer mechanisms and photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Girish Kumar, S., E-mail: girichem@yahoo.co.in; Koteswara Rao, K.S.R., E-mail: raoksrk@gmail.com

    2015-11-15

    Graphical abstract: - Highlights: • Photocatalytic applications of WO{sub 3} and Bi{sub 2}WO{sub 6} based nanomaterial are reviewed. • Modifications to improve their performance are highlighted. • Charge carrier generation–separation–recombination is discussed. • Challenges and future prospects in this area are addressed. - Abstract: Heterogeneous photocatalysis is an ideal green energy technology for the purification of wastewater. Although titania dominates as the reference photocatalyst, its wide band gap is a bottleneck for extended utility. Thus, search for non-TiO{sub 2} based nanomaterials has become an active area of research in recent years. In this regard, visible light absorbing polycrystalline WO{sub 3} (2.4–2.8 eV) and Bi{sub 2}WO{sub 6} (2.8 eV) with versatile structure-electronic properties has gained considerable interest to promote the photocatalytic reactions. These materials are also explored in selective functional group transformation in organic reactions, because of low reduction and oxidation potential of WO{sub 3} CB and Bi{sub 2}WO{sub 6} VB, respectively. In this focused review, various strategies such as foreign ion doping, noble metal deposition and heterostructuring with other semiconductors designed for efficient photocatalysis is discussed. These modifications not only extend the optical response to longer wavelengths, but also prolong the life-time of the charge carriers and strengthen the photocatalyst stability. The changes in the surface-bulk properties and the charge carrier transfer dynamics associated with each modification correlating to the high activity are emphasized. The presence of oxidizing agents, surface modification with Cu{sup 2+} ions and synthesis of exposed facets to promote the degradation rate is highlighted. In depth study on these nanomaterials is likely to sustain interest in wastewater remediation and envisaged to signify in various green energy applications.

  5. Preparation, characterization and photocatalytic behavior of WO3-TiO2/Nb2O5 catalysts

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    TiO2/Nb2O5 photocatalyst loaded with WO3 (WO3-TiO2/Nb2O5) was prepared by a modified hydrolysis process, and characterized by X-ray diffractometry, transmission electron microscopy, Raman spectra and UV-Vis diffuse refraction spectroscopy.The photocatalytic activity of WO3-TiO2/Nb2O5 was investigated by employing splitting of water for O2 evolution. The results indicate that WO3 loading can pronouncedly improve the photocatalytic activity of TiO2/Nb2O5 by using Fe3+ as an electron acceptor under UV irradiation. The optimum molar fraction of the loaded WO3 is 2%, and the largest speed of O2 evolution for 2%WO3-TiO2/Nb2O5 catalyst is 151.8 μmol/(L·h).

  6. Improvement on the Luminescence Property of Y, Sb Co-doped PbWO4 Single Crystal

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of Y and Sb co-doping on the luminescence property of PbWO4 crystals has been investigated. Compared with undoped PbWO4, the transmittance and emission peak intensity of Y∶Sb∶PbWO4 crystals were obviously improved. In addition, its transmittance cutoff wavelength and emission peak shifted to the shorter one. The mechanism of effect of Y and Sb on the transmittance spectra was briefly discussed. The light yield of Y∶Sb∶PbWO4 crystals was 25p.e./MeV, which was two times of that of undoped PbWO4. Our experiments showed that Y and Sb co-doping was a selectable method to improve the luminescence property of PbWO4.

  7. 纳米WO3-ZnS系H2S气敏元件的研究%Study on H2S gas sensor of WO3-ZnS nanosized material

    Institute of Scientific and Technical Information of China (English)

    黄世震; 林伟; 陈伟; 陈知前

    2001-01-01

    The H2S gas sensor is made by nanosized WO3 doped with SnO2, ZnS. It shows that ZnS-WO3 gas sensor to H2S has high sensitivity and good selectivity.%以纳米WO3材料,分别掺入SnO2、ZnS,制备成H2S气敏元件。实验表明,当WO3掺入适量ZnS,元件对H2S气体具有较高的灵敏度及选择性。

  8. Effects of electrolyte concentration and current density on the properties of electro-deposited NiFeW alloy coatings

    Indian Academy of Sciences (India)

    J K YU; H SUN; L L ZHAO; Y H WANG; M Q YU; H L LUO; Z F XU; KAZUHIRO MATSUGI

    2017-06-01

    NiWP alloy coatings were prepared by electrodeposition, and the effects of ferrous chloride (FeCl$_2$), sodium tungstate (Na$_2$WO$_4$) and current density ($D_K$) on the properties of the coatings were studied. The results show that upon increasing the concentration of FeCl$_2$, initially the Fe content of the coating increased and then tended to be stable; the deposition rate and microhardness of coating decreased when the cathodic current efficiency ($\\eta$) initially increased and then decreased; and for a FeCl$_2$ concentration of 3.6 gl$^{−1}, the cathodic current efficiency reached its maximum of 74.23%. Upon increasing the concentration of Na$_2$WO$_4$, the W content and microhardness of the coatings increased; the deposition rate andthe cathode current efficiency initially increased and then decreased. The cathodic current efficiency reached the maximum value of 70.33% with a Na$_2$WO$_4$ concentration of 50 gl$^{−1}$, whereas the deposition rate is maximum at 8.67 $\\mu$mh$^{−1}$ with a Na$_2$WO$_4$ concentration of 40 gl$^{−1}$. Upon increasing the $D_K$, the deposition rate, microhardness, Fe and W content of the coatings increased, the cathodic current efficiency increases first increased and then decreased. When $D_K$ was 4 A dm$^{−2}$,the current efficiency reached the maximum of 73.64%.

  9. Aiming at development of a technology that is welcomed by customers and that sees one step ahead; Okyakusama ni yorokobareru ipposaki wo mita gijutsu kaihatsu wo mezashite

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, K. [Kansai Electric Power Co. Inc., Osaka (Japan)

    1998-11-10

    This paper describes technological development at the Kansai Cable Service Company. A momentary voltage drop monitoring system detects momentary power failure at substations in the load system, transmits and aggregates the information at branch offices via control stations. Data are processed into readily identifiable information, and displayed quickly on branch office terminals or at sales offices. In a TV wave reception disturbance survey, the disturbance can be surveyed by utilizing the image quality evaluation characteristics of MPEG2 that can store animated images of good quality in digital data. The SS wireless system consists of a wireless transmission device intended for remote monitoring and image information transmission. The communications distribution frame control system puts terminal information (the number of terminals exceed several hundred thousand depending a case) into a database, and structures a system by using a low-cost general purpose personal computer which can perform information retrieval and terminal table preparation easily in a short time. The system improved the efficiency and accuracy of the control operation. A PHS quasi animated image transmitting system was also developed. A CATV telephone system and a CATV Internet system were investigated and studied as an experimental study on wide-area multi-media service. (NEDO)

  10. Feasibility of hydrogen production from seaweeds by fermentation; Kaiso wo kishitsu ni riyoshita hakoho ni yoru suiso seisan no kanosei ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Tanisho, Shigeharu; Suganuma, Takeshi [Yokohama National University, Kanagawa (Japan)

    1999-06-01

    To use kelps as a substrate for fermentative hydrogen production by Enterobacter aerogenes strain E.82005, hydrogen evolution rates and yields from mannitol were measured under various salt-concentration cultures. Under non-salt condition, they were 13 mmol per litter culture per hour and 1.6 mol H{sub 2} per mol mannitol, as compared with these, under salt condition 1%, 2%, and 3%, they were 9.9 and 1.5, 4.3 and 1.2, and 3.0 and 0.9, respectively. From these results, we concluded that the production of hydrogen is suitable under non-salt condition, but lower salt condition than seawater especially around 1% is allowable for practical production of hydrogen. The higher yield of H{sub 2} from mannitol than from glucose was clearly shown from the mass balance between evolved H{sub 2} and calculated H2 from metabolite. (author)

  11. For diffusion of environment-friendly products. Environment-friendly shopping campaign; Kankyo ni yasashii shohin no fukyu wo mezashite. Kankyo ni yasashii kaimono undo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Kitano, M.

    1996-05-05

    This paper presents the activity of a consumers` organization in Hyogo-ken for diffusion of environment-friendly products. The product evaluation committee lists the concept of such products as follows: less consumption of resources and energy, possible cyclic reuses, reasonable and appropriate package, and less refuse and possible reuse as resource. This committee determines the products to be recommended, based on selection of products and producers, questionnaire answers, and survey results by consumer monitors and specialist group. The current number of recommended products is 24 in group or 312 in brand, and a half of such products are composed of recycled paper, aluminum and plastic products. The recommended products are renewed every two years. Although the recommended products have steadily increased during the activity for 5 years, the kinds of products are insufficient because of high price, less kinds of products, and insufficient PR. Education, wide information supply (symbol mark), and promotion activity for purchase (joint purchase, model shop) are important in the future. 1 fig., 1 tab.

  12. Template-Free Fabrication of Bi2WO6 Hierarchical Hollow Microspheres with Visible-Light-Driven Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Yuxue Zhou

    2016-09-01

    Full Text Available Highly hierarchical hollow bismuth tungstate (Bi2WO6 microspheres self-assembled by thin nanoplates have been fabricated via a facile template-free solvothermal route. The possible growth pattern and formation mechanism of hierarchical hollow Bi2WO6 microspheres was investigated. The excellent visible-light-driven photocatalytic performance on rhodamine B (RhB degradation was displayed by hierarchical hollow Bi2WO6 microspheres. Such well-organized hierarchical hollow Bi2WO6 microspheres show potential application in water treatment fields by full use of solar energy.

  13. Inductive effect of poly(vinyl pyrrolidone) on morphology and photocatalytic performance of Bi2WO6

    Science.gov (United States)

    Zhang, Qiang; Chen, Jinxing; Xie, Yunyun; Wang, Mozhen; Ge, Xuewu

    2016-04-01

    Bi2WO6 has great potential applications in the field of photocatalyst due to its excellent visible-light photocatalytic performance. This work studied the detailed morphological evolution of Bi2WO6 particles synthesized in a simple hydrothermal system induced by the stabilizer poly(vinyl pyrrolidone) (PVP). The XRD and HRTEM results show PVP would not change the crystal structure of Bi2WO6, but the distribution of PVP on the initially formed Bi2WO6 nanosheets will induce the crystal growth, resulting in a distinct morphology evolution of Bi2WO6 with the increase of the concentration of PVP. At the same time, with the increase of the molecular weight of PVP, the morphology of Bi2WO6 varied from simple sheet-like (S-BWO) to some complicated morphology, such as flower-like (F-BWO), red blood cell-like (B-BWO), and square-pillar-like (SP-BWO). The photocatalytic performances of Bi2WO6 with various morphologies on the decomposition of RhB under visible light irradiation reveal that S-BWO has the best photocatalytic performance, while SP-BWO has the worst. This work not only gives the explanation of the inductive effect of PVP molecular chains on the morphological formation of Bi2WO6 particles, but also provides the controllable way to the preparation of Bi2WO6 with various morphologies taking advantage of the stabilizer PVP.

  14. Synthesis of WO 3 nanoparticles for superthermites by the template method from silica spheres

    Science.gov (United States)

    Gibot, Pierre; Comet, Marc; Vidal, Loic; Moitrier, Florence; Lacroix, Fabrice; Suma, Yves; Schnell, Fabien; Spitzer, Denis

    2011-05-01

    Nanosized WO 3 tungsten trioxide was prepared by calcination of H 3P 4W 12O 40· xH 2O phosphotungstic acid, previously dissolved in a silica colloidal solution. The influence of the silica spheres/tungsten precursor weight ratio ( x) was investigated. The pristine oxide powders were characterized by XRD, nitrogen adsorption, SEM and TEM techniques. A specific surface area and a pore volume of 64.2 m 2 g -1 and 0.33 cm 3 g -1, respectively, were obtained for the well-crystallized WO 3 powder prepared with x = 2/3 and after the removal of the silica template. The WO 3 particles exhibit a sphere-shaped morphology with a particle size of 13 and 320 nm as function of the x ratio. The performance and the sensitivity levels of the thermites prepared from aluminium nanoparticles mixed with (i) the smallest tungsten (VI) oxide material and (ii) the microscale WO 3 were compared. The combustion of these energetic composites was investigated by time resolved cinematography (TRC). This unconventional experimental technique consists to ignite the dried compressed composites by using a CO 2 laser beam, in order to determine their ignition delay time (IDT) and their combustion rate. The downsizing WO 3 particles improves, without ambiguity, the energetic performances of the WO 3/Al thermite. For instance, the ignition delay time was greatly shortened from 54 ± 10 ms to 5.7 ± 0.2 ms and the combustion velocity was increased by a factor 50 to reach a value of 4.1 ± 0.3 m/s. In addition, the use of WO 3 nanoparticles sensitizes the mixture to mechanical stimuli but decreases the sensitivity to electrostatic discharge.

  15. Structural evolution, growth mechanism and photoluminescence properties of CuWO4 nanocrystals.

    Science.gov (United States)

    Souza, E L S; Sczancoski, J C; Nogueira, I C; Almeida, M A P; Orlandi, M O; Li, M S; Luz, R A S; Filho, M G R; Longo, E; Cavalcante, L S

    2017-09-01

    Copper tungstate (CuWO4) crystals were synthesized by the sonochemistry (SC) method, and then, heat treated in a conventional furnace at different temperatures for 1h. The structural evolution, growth mechanism and photoluminescence (PL) properties of these crystals were thoroughly investigated. X-ray diffraction patterns, micro-Raman spectra and Fourier transformed infrared spectra indicated that crystals heat treated and 100°C and 200°C have water molecules in their lattice (copper tungstate dihydrate (CuWO4·2H2O) with monoclinic structure), when the crystals are calcinated at 300°C have the presence of two phase (CuWO4·2H2O and CuWO4), while the others heat treated at 400°C and 500°C have a single CuWO4 triclinic structure. Field emission scanning electron microscopy revealed a change in the morphological features of these crystals with the increase of the heat treatment temperature. Transmission electron microscopy (TEM), high resolution-TEM images and selected area electron diffraction were employed to examine the shape, size and structure of these crystals. Ultraviolet-Visible spectra evidenced a decrease of band gap values with the increase of the temperature, which were correlated with the reduction of intermediary energy levels within the band gap. The intense photoluminescence (PL) emission was detected for the sample heat treat at 300°C for 1h, which have a mixture of CuWO4·2H2O and CuWO4 phases. Therefore, there is a synergic effect between the intermediary energy levels arising from these two phases during the electronic transitions responsible for PL emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Structural, vibrational and luminescence properties of the (1−x)CaWO{sub 4}−xCdWO{sub 4} system

    Energy Technology Data Exchange (ETDEWEB)

    Taoufyq, A. [Institut Matériaux Microélectronique et Nanosciences de Provence, Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 83957, La Garde (France); Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir, Maroc (Morocco); CEA/DEN, Département d’Études des Réacteurs, Laboratoire Dosimétrie Capteurs Instrumentation, CEA Cadarache, 13108, Saint-Paul-lez-Durance (France); Société CESIGMA, Signals and Systems, 1576 Chemin de La Planquette, 83130 La Garde (France); Guinneton, F.; Valmalette, J-C.; Arab, M. [Institut Matériaux Microélectronique et Nanosciences de Provence, Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 83957, La Garde (France); Benlhachemi, A.; Bakiz, B. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir, Maroc (Morocco); Villain, S. [Institut Matériaux Microélectronique et Nanosciences de Provence, Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 83957, La Garde (France); and others

    2014-11-15

    In the present work, we investigate the structural, microstructural, vibrational and luminescence properties of the system (1−x)CaWO{sub 4}−xCdWO{sub 4} with x ranging between 0 and 1. Polycrystalline samples were elaborated using a coprecipitation technique followed by thermal treatment at 1000 °C. The samples were then characterized using X-ray diffraction, scanning electron microscopy, Raman spectroscopy and luminescence analyses. X-ray diffraction profile analyses using Rietveld method showed that two kinds of solid solutions Ca{sub 1−x}Cd{sub x}WO{sub 4} having scheelite and wolframite structures, with respectively tetragonal and monoclinic crystal cells, were observed, with a biphasic system for compositions x=0.6 and 0.7. The scanning electron microscopy experiments showed a complex evolution of morphologies and crystallite sizes as x increased. The vibration modes of Raman spectra were characteristic of composition-dependent disordered solid solutions with decreasing wavenumbers as x increased. Luminescence experiments were performed under UV-laser light irradiation. The energies of emission bands increased linearly with cadmium composition x. The integrated intensity of luminescence reached a maximum value for the substituted wolframite phase with composition x=0.8. - Graphical abstract: Luminescence on UV excitation (364.5 nm) of (1−x)CaWO{sub 4−x}CdWO{sub 4} system, elaborated from coprecipitation technique at 1000 °C, with 0WO{sub 4} polycrystalline phases with 0≤x≤0.5. (b) Maximum of luminescence intensity for the composition x=0.8. - Highlights: • Solid solutions Ca{sub 1−x}Cd{sub x}WO{sub 4} are elaborated from coprecipitation technique. • The structures of two types of solid solutions are refined using Rietveld method. • A maximum of luminescence is obtained for an intermediate composition x=0.8.

  17. Synthesis and characterization of MnWO4 nanoparticles encapsulated in mesoporous silica SBA-15 by fast microwave-assisted method

    Science.gov (United States)

    Hoang, Luc Huy; Hanh, Pham Van; Phu, Nguyen Dang; Chen, Xiang-Bai; Chou, Wu Ching

    2015-02-01

    The MnWO4 nanoparticles encapsulated in mesoporous silica (MnWO4/SBA-15) was successfully synthesized by a fast microwave-assisted method. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen absorption-desorption isotherm, and Fourier transform infrared spectroscopy (FTIR). Our results showed that the MnWO4/SBA-15 nanocomposites have the ordered hexagonal meso-structure of SBA-15, indicating MnWO4 nanoparticles were successfully distributed into the channels of SBA-15. The size of MnWO4 nanoparticles in SBA-15 is significantly smaller than the size of MnWO4 nanoparticles prepared without SBA-15, indicating that the MnWO4/SBA15 nanocomposites would be very promising for improving photocatalytic activity of MnWO4 nanoparticles.

  18. Ethylene Separation via Hydrate Formation in W/O Emulsions

    Directory of Open Access Journals (Sweden)

    Yong Pan

    2015-05-01

    Full Text Available An hybrid absorption-hydration method was adopted to recover C2H4 from C2H4/CH4 binary gas mixtures and the hydrate formation conditions of C2H4/CH4 mixtures was studied experimentally in diesel in water (w/o emulsions. Span 20 at a concentration of 1.0 wt% in the aqueous phase was added to form water in diesel emulsions before hydrate formation and then hydrate in diesel slurry was separated after hydrate formation. The influences of initial gas-liquid volume ratio (53–142, pressure (3.4–5.4 MPa, temperature (274.15–278.15 K, water cuts (10–30 vol%, and the mole fraction of C2H4 in feed gas (13.19–80.44 mol% upon the C2H4 separation efficiency were systematically investigated. The experimental results show that ethylene can be enriched in hydrate slurry phase with high separation factor (S and recovery ratio (R. Most hydrate formation finished in 20 min, after that, the hydrate formation rate became very slow. The conclusion is useful for determining the suitable operation conditions when adopting an absorption-hydration method to separate C2H4/CH4.

  19. CdWO4 bolometers for Double Beta Decay search

    CERN Document Server

    Gironi, L; Capelli, S; Cremonesi, O; Pavan, M; Pessina, G; Pirro, S

    2008-01-01

    In the field of Double Beta Decay (DBD) searches the possibility to have high resolution detectors in which background can be discriminated is very appealing. This very interesting possibility can be largely fulfilled in the case of a scintillating bolometer containing a Double Beta Decay emitter whose transition energy exceeds the one of the natural gamma line of 208Tl. We present the latest results obtained in the development of such a kind of scintillating bolometer. For the first time an array of five CdWO4 (116Cd has a Double Beta Decay transition energy of 2805 keV) crystals is tested. The array consists of a plane of four 3x3x3 cm3 crystals and a second plane consisting of a single 3x3x6 cm3 crystal. This setup is mounted in hall C of the National Laboratory of Gran Sasso inside a lead shielding in order to reduce as far as possible the environmental background. The aim of this test is to demonstrate the technical feasibility of this technique through an array of detectors and perform a long background...

  20. Chromic mechanism in amorphous WO{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J G; Benson, D K; Tracy, C E; Deb, S K; Czanderna, A W [National Renewable Energy Lab., Golden, CO (United States); Bechinger, C [Universitaet Konstanz (Germany)

    1996-11-01

    The authors propose a new model for the chromic mechanism in amorphous tungsten oxide films (WO{sub 3{minus}y}{center_dot}nH{sub 2}O). This model not only explains a variety of seemingly conflicting experimental results reported in the literature that cannot be explained by existing models, it also has practical implications with respect to improving the coloring efficiency and durability of electrochromic devices. According to this model, a typical as-deposited tungsten oxide film has tungsten mainly in W{sup 6+} and W{sup 4+} states and can be represented as W{sub 1{minus}y}{sup 6+} W{sub y}{sup 4+}O{sub 3{minus}y}{center_dot}nH{sub 2}O. The proposed chromic mechanism is based on the small polaron transition between the charge-induced W{sup 5+} state and the original W{sup 4+} state instead of the W{sup 5+} and W{sup 6+} states as suggested in previous models. The correlation between the electrochromic and photochromic behavior in amorphous tungsten oxide films is also discussed.

  1. TiO2(B) nanoparticle-functionalized WO3 nanorods with enhanced gas sensing properties.

    Science.gov (United States)

    Zhang, Hongxin; Wang, Shurong; Wang, Yanshuang; Yang, Jiedi; Gao, Xueling; Wang, Liwei

    2014-06-14

    In this work, TiO2(B) nanoparticle (NP)-functionalized WO3 nanorods (NRs) were synthesized by a two-step solution strategy, with a hydrothermal process for WO3 NRs and hydrolyzation of Ti(OBu)4 for the functionalization of TiO2(B) NPs. Various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), were employed to investigate the morphology, microstructure, crystalline nature and chemical composition of the prepared TiO2(B) NP-functionalized WO3 NRs. SEM and TEM results revealed that the TiO2(B)-WO3 composite showed a rod-like nanostructure with a diameter in the range from 93 to 154 nm and a rough surface, which could increase the accessible surface area and the amount of surface active sites, thus improving the properties or performance of the as-prepared composite NRs. XRD and XPS analysis clearly verified that monoclinic TiO2(B) NPs, a metastable polymorph of TiO2, were successfully supported on the WO3 NRs. Gas sensing measurement results for several common reductive organic gases such as acetone, ethanol, ether, methanol and formaldehyde demonstrated that the sensor based on the as-obtained TiO2(B) NP-functionalized WO3 NRs exhibited obviously enhanced responses compared with a pure WO3 NR based sensor, as well as fast response-recovery speeds, good reproducibility and good stability, indicating their promising application in gas sensors. The excellent gas sensing performance could be attributed to the unique 1D rod-like nanostructure with a rough surface, the existence of TiO2-WO3 heterojunctions and the catalytic effect of the TiO2(B) NPs. The as-prepared TiO2(B) NP-functionalized WO3 NRs will also have very good prospects in electrochromic devices and catalysis applications.

  2. Study on Preparation and Photochromism of WO3-TiO2-ZnO Colloid%WO3-TiO2-ZnO溶胶的制备及其光致变色性能研究

    Institute of Scientific and Technical Information of China (English)

    陈伟龙; 沈鸿烈; 王威; 李金泽

    2014-01-01

    采用溶胶-凝胶法分别制备了WO3,TiO2和ZnO溶胶,在此基础上以一定比例混合后形成WO3-TiO2-ZnO和WO3-TiO2溶胶.利用透射电镜和紫外-可见分光光度计对其进行了表征.结果表明,WO3-TiO2-ZnO溶胶粒子尺寸分布在10~25 nm范围,WO3-TiO2-ZnO溶胶比WO3溶胶和WO3-TiO2溶胶具有更好的光致变色性能.用500 w汞灯照射80s后,WO3-TiO2-ZnO溶胶由无色变为蓝色,变色后的溶胶在无光照6h左右后由蓝色恢复到无色,具有很好的光致变色行为的可逆性.

  3. Gold clusters on WO{sub 3} nanoneedles grown via AACVD: XPS and TEM studies

    Energy Technology Data Exchange (ETDEWEB)

    Navio, Cristina [Laboratory of Interaction Chemistry on Plasma Surfaces, University of Mons (Belgium); Vallejos, Stella [MINOS, EMaS, Departament d' Enginyeria Electronica, Universitat Rovira i Virgili, Tarragona (Spain); Department of Chemistry, University College London, London, WC1H 0AJ (United Kingdom); Stoycheva, Toni; Llobet, Eduard; Correig, Xavier [MINOS, EMaS, Departament d' Enginyeria Electronica, Universitat Rovira i Virgili, Tarragona (Spain); Snyders, Rony [Laboratory of Interaction Chemistry on Plasma Surfaces, University of Mons (Belgium); Blackman, Christopher [Department of Chemistry, University College London, London, WC1H 0AJ (United Kingdom); Umek, Polona [Solid State Physcis Department Jozef Stefan Institute, Jamov cesta 39, 1000 Ljubljana (Slovenia); Ke Xiaoxing; Van Tendeloo, Gustaaf [Electron Microscopy for Material Science, University of Antwerp, Antwerp (Belgium); Bittencourt, Carla, E-mail: carla.bittencourt@umons.ac.be [Electron Microscopy for Material Science, University of Antwerp, Antwerp (Belgium)

    2012-06-15

    We have prepared tungsten oxide films decorated with gold particles on Si substrates by aerosol assisted chemical vapor deposition (AACVD) and characterized them using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). SEM shows that the films are composed of needle-like structures and TEM shows that both the needles and the gold particles are crystalline. XPS indicates the presence of oxygen vacancies, i.e. the films are WO{sub 3-x}, and hence the deposited material is composed of semiconducting nanostructures and that the interaction between the gold particles and the WO{sub 3} needles surface is weak. The synthesis of semiconducting tungsten oxide nanostructures decorated with metal particles represents an important step towards the development of sensing devices with optimal properties. - Highlights: Black-Right-Pointing-Pointer Characterization of WO{sub 3} needle-like structures decorated with gold nanoparticles. Black-Right-Pointing-Pointer WO{sub 3} needle-like structures are crystalline. Black-Right-Pointing-Pointer WO{sub 3} needle-like structures are semiconducting.

  4. Preparation and physical properties of Cu{sub x}WO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Koriche, N. [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry, U.S.T.H.B., BP 32, 16111 El-Alia, Algiers (Algeria); Bessekhouad, Y., E-mail: ybessekhouad@yahoo.fr [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry, U.S.T.H.B., BP 32, 16111 El-Alia, Algiers (Algeria); National Veterinary School, BP 161-El Harrach, Algiers (Algeria); Bouguelia, A.; Trari, M. [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry, U.S.T.H.B., BP 32, 16111 El-Alia, Algiers (Algeria)

    2012-04-01

    We report on the study of WO{sub 3} doped with Cu using sol-gel (Cu{sub x}WO{sub 3}{sup d}) and impregnation (Cu{sub x}WO{sub 3}{sup i}) methods. All materials are well crystallized and exhibit single phases whose crystallite size ranges from 17 to 100 nm depending on Cu amount and the preparation technique. The conductivity dependence on temperature demonstrates semiconductor behavior and follows the Arrhenius model, with activation energies, E{sub {sigma}}, commonly in the range 0.4-0.6 eV. Moreover, the thermopower study shows that Cu{sub x}WO{sub 3}{sup d} is mainly of p-type conductivity, whereas Cu{sub x}WO{sub 3}{sup i} is n-type. The mechanism of conduction is attributed to a small polaron hopping. The doping process is found to decrease the interband transition down to 520 nm depending on the preparation conditions. The photoelectrochemical characterization confirms the conductivity type and demonstrates that the photocurrent J{sub ph} increases with Cu-doping. Taking into consideration the activation energy, the flat band potential and the band gap energy, the band positions of each material are proposed according to the preparation method and Cu amount.

  5. Non-stoichiometry Defects and Radiation Hardness of Lead Tungstate Crystals PbWO4

    CERN Document Server

    Devitsin, E G; Kozlov, V A; Nefedov, L; Polyansky, E V; Potashov, S Yu; Terkulov, A R; Zadneprovski, B I

    2001-01-01

    It has been stated many times that the formation of radiation infringements in PbWO4 is to big extent stipulated by non-stoichiometry defects of the crystals, arising in the process of their growth and annealing. To refine the idea of characteristics of non-stoichiometry defects and their effect on the radiation hardness of PbWO4 the current study is aimed at the melt composition infringements during its evaporation and at optical transmission of crystals obtained in these conditions after their irradiation (137Cs source). In the optical transmission measurements along with traditional techniques a method "in situ" was used, which provided the measurements in fixed points of the spectrum (380, 470 and 535 nm) directly in the process of the irradiation. X-ray phase and fluorescence analysis of condensation products of vapours over PbWO4 melt has found PbWO4 phase in their content as well as compounds rich in lead, PbO, Pb2WO5, with overall ratio Pb/W = 3.2. Correspondingly the lack of lead and variations in th...

  6. Production of CaWO{sub 4} crystals for direct dark matter search with CRESST

    Energy Technology Data Exchange (ETDEWEB)

    Muenster, Andrea [Physik-Department and Excellence Cluster Universe, Technische Universitaet Muenchen, D-85748 Garching (Germany); Collaboration: CRESST-Collaboration

    2016-07-01

    The direct dark matter search experiment CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) uses scintillating CaWO{sub 4} single crystals as targets for possible recoils of dark matter particles. Since several years these CaWO{sub 4} crystals are produced directly at the Technische Universitaet Muenchen (TUM) including the CaWO{sub 4} powder production from the raw materials CaCO{sub 3} and WO{sub 3}, the CaWO{sub 4} crystal growth via the Czochralski method as well as the after-growth treatment of the crystals. In the recently finished CRESST-II Phase 2 (2013-2015), 4 TUM-grown crystals were installed in the main cryostat for the first time. Showing one of the best radiopurities of all installed crystals combined with an excellent detector performance the analysis of the crystal TUM40 resulted in the best sensitivity for low-mass dark matter particles in 2014. For the upcoming CRESST-III phase 2 we aim for a further improvement in radiopurity by a factor of 100. First results of a chemical purification of the raw materials as well as future plans to reduce the intrinsic background via recrystallization are presented.

  7. The Facile Hydrothermal Preparation of Orthorhombic WO3 With (001) Facet and Its Photocatalytic Performance.

    Science.gov (United States)

    Deng, Xiaoyan; Dou, Jinbiao; Li, Fenfen; Gao, Hongtao; Liu, Guangjun

    2015-12-01

    The orthorhombic WO3 nanoplates with (001) facet were fabricated via a facile hydrothermal process, using HBF4 as the acid source. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis diffused reflectance spectroscopy (DRS), respectively. It indicated that the obtained product was orthorhombic WO3 (JCPDS No. 20-1324). And the energy gap was estimated to be 2.52 eV by the intersection point of the tangent of the absorption edge and the baseline. It was affirmed that WO3 crystalline grew along the (001) direction, indicating the product was exposed with (001) facet. The photocatalytic activity of (001) WO3 nanoplates was investigated on the degradation of Rhodamine B (RhB). It demonstrated that photocatalysts exhibited obvious photocatalytic performance under visible light irradiation. The degradation rate of RhB with the typical product reached 95% after being irradiated for 5 h. It indicated that the photocatalytic efficiency of WO3 could be improved by controlling the crystal growth and its morphology.

  8. Synthesis of ZnWO4 Electrode with tailored facets: Deactivating the Microorganisms through Photoelectrocatalytic methods

    Science.gov (United States)

    Zhan, Su; Zhou, Feng; Huang, Naibao; Liu, Yujun; He, Qiuchen; Tian, Yu; Yang, Yifan; Ye, Fei

    2017-01-01

    The exotic invasive species from the ballast water in the ship will bring about serious damages to ecosystem. Photocatalyst films have been widely studied for sterilization. In this study, ZnWO4 with different exposed facets was synthesized by hydrothermal method, and ZnWO4 film electrodes have been applied in ballast water treatment through the electro-assisted photocatalytic system. Then the samples were investigated by X-ray diffraction (XRD), X-ray photo-electron spectroscopy (XPS), Field emission on scanning electron microcopy (FE-SEM), Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), BET specific surface area analysis, Fourier transform infrared (FT-IR) and Electrochemical impedance spectra (EIS). ZnWO4 with an appropriate exposure of (0 1 1) facets ratio exhibited the best photocatalytic and photoelectrocatalytic activities. The microorganisms deactivated completely in 10 min by ZnWO4 films with 3 V bias. The mechanisms of (0 1 1) facets enhanced the photocatalytic and photoelectrocatalytic activities which were deduced based on the calculated result from the first principles. Simultaneously, appropriate exposed facets and applied bias could reduce the recombination of the photogenerated electron-hole pairs, and improve the photocatalytic activities of ZnWO4.

  9. Fabrication of ZnWO{sub 4} nanofibers by a high direct voltage electrospinning process

    Energy Technology Data Exchange (ETDEWEB)

    Keereeta, Yanee [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun, E-mail: ttpthongtem@yahoo.com [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Somchai [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2011-06-09

    Highlights: > ZnWO{sub 4} nanofibers as one of semiconducting materials. > A lab-made electrospinning equipment enables to form fibrous precursors. > Upon calcination the precursors above 500 deg. C, ZnWO{sub 4} nanofibers are produced. > The promising nanofibers for photoluminescence devices and solar cells. - Abstract: Mixtures of zinc acetate dihydrate, ammonium metatungstate hydrate, and 5 wt%, 6 wt%, and 7 wt% of poly (vinyl alcohol) (PVA) were electrospun by a +15 kV direct voltage to produce fibers. In the present research, the electrospun fibers of 6 wt% PVA were further calcined at 400-600 deg. C for 3 h. The sanmartinite monoclinic structured ZnWO{sub 4} was detected by X-ray diffractometer (XRD) and selected area electron diffraction (SAED), weight loss by thermogravimetric analyser (TGA), morphology and particle size by scanning and transmission electron microscopes (SEM, TEM) and atomic force microscope (AFM), including their vibration modes by Fourier transform infrared spectrometer (FTIR) and Raman spectrometer. The 4.42 eV direct energy gap (E{sub g}) and 460 nm emission wavelength, caused by the electronic transition of (WO{sub 6}){sup 2-} octahedrons, were determined by UV-visible absorption and photoluminescence (PL) spectrometers. A possible formation mechanism of ZnWO{sub 4} nanofibers was also proposed according to the experimental results.

  10. Non-stoichiometry defects and radiation hardness of lead tungstate crystals PbWO sub 4

    CERN Document Server

    Devitsin, E G; Potashov, S Yu; Terkulov, A R; Nefedov, V A; Polyansky, E V; Zadneprovski, B I; Kjellberg, P; Korbel, V

    2002-01-01

    It has been stated many times that the formation of radiation infringements in PbWO sub 4 is to a big extent stipulated by the non-stoichiometry defects of the crystals, arising in the process of their growth and annealing. To refine the idea of characteristics of the non-stoichiometry defects and their effect on the radiation hardness of PbWO sub 4 , the current study is aimed at the melt composition infringements during its evaporation and at optical transmission of crystals obtained in these conditions after their irradiation ( sup 1 sup 3 sup 7 Cs source). In the optical transmission measurements along with traditional techniques a method 'in situ' was used, which provided the measurements in fixed points of the spectrum (380, 470 and 535 nm) directly in the process of the irradiation. X-ray phase and fluorescence analysis of condensation products of vapours over PbWO sub 4 melt has found PbWO sub 4 phase in their content as well as compounds rich in lead PbO, Pb sub 2 WO sub 5 with overall ratio Pb/W (3....

  11. Facile synthesis of decorated graphene oxide sheets with WO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Adineh, Ensieh; Rasuli, Reza [University of Zanjan, Department of Physics, Faculty of Science, P.O. Box 45371-38791, Zanjan (Iran, Islamic Republic of)

    2015-09-15

    Potential applications of graphene oxide (GO) nanocomposites have attracted remarkable attention to modify its properties by functionalizing and decorating with nanoparticles. In this work, after synthesis of GO sheets by oxidation and exfoliation of natural graphite, they were decorated with tungsten oxide nanoparticles using arc discharge in GO solution. Transmission electron microscopy shows that the chain of WO{sub 3} nanoparticles decorates the GO sheets. Fourier transform infrared spectroscopy and Raman spectroscopy show that WO{sub 3} nanoparticles are attached to GO sheets by bond formation between the tungsten and oxygen of functional groups, especially with epoxides on the GO sheets. Nanocomposite production in different arc currents shows that the greater the electrical current, the stronger the bond is formed between WO{sub 3} and GO. X-ray diffraction confirms that the WO{sub 3} nanoparticles on the GO are highly crystalline in monoclinic phase. Moreover, by increasing the arc current from 20 to 40 A, the band gap energy of GO + WO{sub 3} decreases to ∝2.6 eV. (orig.)

  12. Synthesis of chemically bonded BiOCl@Bi{sub 2}WO{sub 6} microspheres with exposed (0 2 0) Bi{sub 2}WO{sub 6} facets and their enhanced photocatalytic activities under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yongchao [Qingdao Agricultural University, Qingdao 266109 (China); Chen, Zhiwei [School of Life Sciences, Shandong University of Technology, Zibo 255049 (China); Qu, Dan [Qingdao Agricultural University, Qingdao 266109 (China); Shi, Jinsheng, E-mail: jsshiqn@aliyun.com [Qingdao Agricultural University, Qingdao 266109 (China)

    2016-01-15

    Graphical abstract: - Highlights: • BiOCl@Bi{sub 2}WO{sub 6} composites were prepared via a controlled anion exchange method. • The shell of composites was composed of Bi{sub 2}WO{sub 6} sheets with exposed (0 2 0) facets. • The BiOCl@Bi{sub 2}WO{sub 6} composites showed efficient photocatalytic activity. • A possible photocatalytic degradation mechanism is proposed. - Abstract: Bi{sub 2}WO{sub 6} photocatalysts has been extensively studied for its photocatalytic activity. However, few works have been conducted on hierarchical Bi{sub 2}WO{sub 6} composite photocatalysts with specifically exposed facets. In this work, we report a facile method to synthesize BiOCl@Bi{sub 2}WO{sub 6} hierarchical composite microspheres. Bi{sub 2}WO{sub 6} nanosheets with specifically exposed (0 2 0) facet were directly formed on the surface of BiOCl precursor microspheres via a controlled anion exchange route between BiOCl and Na{sub 2}WO{sub 4}. The visible-light photocatalytic activity of the BiOCl@Bi{sub 2}WO{sub 6} heterojunction with exposed (0 2 0) facets (denoted as BiOCl@Bi{sub 2}WO{sub 6}) was investigated by degradation of Rhodamine B (RhB) and ciprofloxacin (CIP) aqueous solution under visible light irradiation. The experimental results indicated that the BiOCl@Bi{sub 2}WO{sub 6} composite microsphere with intimate interfacial contacts exhibited improved efficiency for RhB photodegradation in comparison with pure BiOCl and Bi{sub 2}WO{sub 6}. The BiOCl@Bi{sub 2}WO{sub 6} composite microsphere also shows high photocatalytic activity for degradation of CIP under visible light irradiation. The enhanced photocatalytic performance of BiOCl@Bi{sub 2}WO{sub 6}-020 hierarchical microspheres can be ascribed to the improved visible light harvesting ability, high charge separation and transfer. This work will make significant contributions toward the exploration of novel heterostructures with high potential in photocatalytic applications.

  13. Fabrication and Characterization of Tailored TiO2and WO3/MWCNT Composites for Methylene Blue Decomposition%Fabrication and Characterization of Tailored TiO2 and WO3/MWCNT Composites for Methylene Blue Decomposition

    Institute of Scientific and Technical Information of China (English)

    ZHU Lei; MENG Zeda; OH Won-Chun

    2011-01-01

    A sol-gel method was used to prepare WO3/MWCNT-TiO2 composites. Their photocatalytic activities were evaluated by the degradation of methylene blue (MB) solution under UV light. The catalysts were characterized by X-ray diffraction, specific surface area measurement, energy-dispersive X-ray analysis, transmission and scanning electron microscopy. Aqueous MB solutions of 100 ml were photode graded by a small amount of the WO3/MWCNT-TiO2 composite under UV light irradiation. The photocatalytic data showed that the WO3/MWCNT-TiO2 composite achieved a high rate of MB photodegradation. This was attributed to the use of MWCNT which can absorb UV light to create photo-induced electrons, strong adsorption of dye molecules on the photocatalyst, and reduced recombination rate of electron-holes in the WO3/MWCNT-TiO2 composite due to the introduction of the WO3 semiconductor.

  14. Rare-earth-ion doped KY(WO4)2 optical waveguides grown by liquid-phase epitaxy

    NARCIS (Netherlands)

    Romanyuk, Y.E.; Apostolopoulos, V.; Utke, U.; Pollnau, Markus

    2004-01-01

    High-quality KY(WO4)2 thin layers doped with rare-earth-ions were grown using liquid-phase epitaxy. A low-temperature mixture of chlorides was used as the flux and undoped KY(WO4)2 crystals as substrates. The crystalline layers possessed thicknesses up to 10 µm. Passive and active planar waveguiding

  15. Enhancement of photoelectric response of bacteriorhodopsin by multilayered WO3 x H2O nanocrystals/PVA membrane.

    Science.gov (United States)

    Li, Rui; Hu, Fengping; Bao, Qiaoliang; Bao, Shujuan; Qiao, Yan; Yu, Shucong; Guo, Jun; Li, Chang Ming

    2010-02-01

    For the first time, a multilayered WO(3) x H(2)O/PVA membrane on bacteriorhodopsin (bR) is constructed to significantly enhance the photoelectric response of bR by the spillover effect of WO(3) x H(2)O nanocrystals, providing great potential in its important applications in bioelectronics and proton exchange membrane fuel cells.

  16. Synthesis, characterization and electrochemical studies of nanostructured CaWO{sub 4} as platinum support for oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Farsi, Hossein [Department of Chemistry, University of Birjand, 97175-615 Birjand (Iran, Islamic Republic of); Solar Energy Research Department, University of Birjand, Birjand (Iran, Islamic Republic of); Barzgari, Zahra, E-mail: zbarzgari@birjand.ac.ir [Department of Chemistry, University of Birjand, 97175-615 Birjand (Iran, Islamic Republic of)

    2014-11-15

    Highlights: • Nanostructured CaWO{sub 4} was fabricated by co-precipitation method. • Platinum was electrodeposited onto the surface prepared nanostructured CaWO{sub 4}. • Pt/CaWO{sub 4}-graphite demonstrate good oxygen reduction reaction activity. - Abstract: In the present work, we employed nanostructured calcium tungstate as a supporting material for platinum, a well-known electrocatalyst for oxygen reduction. The co-precipitation method has been utilized to synthesize nanostructured calcium tungstate from aqueous solution. The structure and morphology of the obtained CaWO{sub 4} were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Preparation of the Pt/CaWO{sub 4}-graphite catalyst was carried out by electrodeposition of Pt onto the surface of CaWO{sub 4}/graphite electrode. The physical properties of the catalyst were determined by scanning electron microscopy analysis and energy dispersive X-ray (SEM/EDX). The electrochemical activity of the Pt/CaWO{sub 4}-graphite for the oxygen reduction reaction (ORR) was investigated in acid solution by cyclic voltammetry measurements, linear sweep voltammetry, and electrochemical impedance spectroscopy. The results revealed that the Pt/CaWO{sub 4}-graphite has higher electrocatalytic activity for oxygen reduction in comparison with Pt/graphite catalyst.

  17. H.sub.2O doped WO.sub.3, ultra-fast, high-sensitivity hydrogen sensors

    Science.gov (United States)

    Liu, Ping; Tracy, C. Edwin; Pitts, J. Roland; Lee, Se-Hee

    2011-03-22

    An ultra-fast response, high sensitivity structure for optical detection of low concentrations of hydrogen gas, comprising: a substrate; a water-doped WO.sub.3 layer coated on the substrate; and a palladium layer coated on the water-doped WO.sub.3 layer.

  18. Photoelectrocatalytic degradation of phthalic acid using spray deposited stratified WO3/ZnO thin films under sunlight illumination

    Science.gov (United States)

    Hunge, Y. M.; Mahadik, M. A.; Moholkar, A. V.; Bhosale, C. H.

    2017-10-01

    In the present work, stratified WO3/ZnO thin films have been prepared by simple chemical spray pyrolysis technique. The structural, morphological, compositional and photoelectrocatalytic properties of the stratified WO3/ZnO thin films are studied. The photoelectrochemical (PEC) study shows that, both short circuit current (Isc) and open circuit voltage (Voc) are (Isc = 1.023 mA and Voc = 0.980 V) relatively high at 40 ml spraying quantity of ZnO solution on pre-deposited WO3 thin films. XRD analysis reveals that stratified WO3/ZnO thin films are polycrystalline with monoclinic and hexagonal crystal structures for WO3 and ZnO respectively. The specific surface area of the stratified WO3/ZnO thin film is found to be 48.12 m2 g-1. The enhanced photoelectrocatalytic activity of stratified WO3/ZnO is mainly due to the suppressing the recombination of photo generated electron-hole pairs. The end result shows that the degradation percentage of phthalic acid (PA) using stratified WO3/ZnO photo electrode has reached 63.63% after 320 min. under sunlight illumination. The amount of mineralization of phthalic acid is studied with the help of chemical oxygen demand (COD) measurement.

  19. Efficient room temperature oxidation of cyclohexane over highly active hetero-mixed WO3/V2O5 oxide catalyst

    CSIR Research Space (South Africa)

    Makgwane, PR

    2014-09-01

    Full Text Available An efficient room temperature catalyzed oxidation of cyclohexane to cyclohexanone (K) and cyclohexanol (A) was achieved over hetero-mixed tungsten–vanadia (WO(sub3)/V(sub2)O(sub5)) using H(sub2)O(sub2) oxidant. WO(sub3)/V(sub2)O(sub5) exhibited high...

  20. High activity of Pd-WO3/C catalyst as anodic catalyst for direct formic acid fuel cell

    Science.gov (United States)

    Feng, Ligang; Yan, Liang; Cui, Zhiming; Liu, Changpeng; Xing, Wei

    2011-03-01

    Pd nanoparticles supported on the WO3/C hybrid are prepared by a two-step procedure and the catalysts are studied for the electrooxidation of formic acid. For the purpose of comparison, phosphotungstic acid (PWA) and sodium tungstate are used as the precursor of WO3. Both the Pd-WO3/C catalysts have much higher catalytic activity for the electrooxidation of formic acid than the Pd/C catalyst. The Pd-WO3/C catalyst prepared from PWA shows the best catalytic activity and stability for formic acid oxidation; it also shows the maximum power density of approximately 7.6 mW cm-2 when tested with a small single passive fuel cell. The increase of electrocatalytic activity and stability is ascribed to the interaction between the Pd and WO3, which promotes the oxidation of formic acid in the direct pathway. The precursors used for the preparation of the WO3/C hybrid support have a great effect on the performance of the Pd-WO3/C catalyst. The WO3/C hybrid support prepared from PWA is beneficial to the dispersion of Pd nanoparticles, and the catalyst has potential application for direct formic acid fuel cell.

  1. Exfoliated thin Bi2MoO6 nanosheets supported on WO3 electrode for enhanced photoelectrochemical water splitting

    Science.gov (United States)

    Ma, Ying; Jia, Yulong; Wang, Lina; Yang, Min; Bi, Yingpu; Qi, Yanxing

    2016-12-01

    Thin Bi2MoO6 nanosheets are obtained by a microwave-assisted ultrasonic separation process. After exfoliation, the thinner and uniform nanosheets with a thickness of about 10 nm were obtained. The exfoliated nanosheets would provide many amazing functionalities such as high electron mobility and quantum Hall effects. Therefore, thin Bi2MoO6 supported on WO3 electrode (WO3/thin Bi2MoO6) exhibits facilitated charge separation than pure WO3 film and the un-exfoliated Bi2MoO6 nanosheets supported on WO3 electrode (WO3/Bi2MoO6). As a result, WO3/thin Bi2MoO6 shows remarkably stable photocurrent density of 2.2 mA/cm2 at 0.8 VSCE in 0.1 M Na2SO4 which is higher than that of that of WO3 (1.1 mA/cm2) and WO3/Bi2MoO6 (1.5 mA/cm2).

  2. Structural properties of WO{sub 3} dependent of the annealing temperature deposited by hot-filament metal oxide deposition

    Energy Technology Data Exchange (ETDEWEB)

    Flores M, J. E. [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias de la Electronica, Av. San Claudio y 18 Sur, Ciudad Universitaria, Col. Jardines de San Manuel, 72570 Puebla (Mexico); Diaz R, J. [IPN, Centro de Investigacion en Biotecnologia Aplicada, Ex-Hacienda de San Molino Km 1.5 Tepetitla, 90700 Tlaxcala (Mexico); Balderas L, J. A., E-mail: eflores@ece.buap.mx [IPN, Unidad Profesional Interdisciplinaria de Biotecnologia, Av. Acueducto s/n, Col. Barrio la Laguna, 07340 Mexico D. F. (Mexico)

    2012-07-01

    In this work presents a study of the effect of the annealing temperature on structural and optical properties of WO{sub 3} that has been grown by hot-filament metal oxide deposition. The chemical stoichiometry was determined by X-ray photoelectron spectroscopy. By X-ray diffraction obtained that the as-deposited WO{sub 3} films present mainly monoclinic crystalline phase. WO{sub 3} optical band gap energy can be varied from 2.92 to 3.15 eV obtained by transmittance measurements by annealing WO{sub 3} from 100 to 500 C. The Raman spectrum of the as-deposited WO{sub 3} film shows four intense peaks that are typical Raman peaks of crystalline WO{sub 3} (m-phase) that corresponds to the stretching vibrations of the bridging oxygen that are assigned to W-O stretching ({upsilon}) and W-O bending ({delta}) modes, respectively, which enhanced and increased their intensity with the annealing temperature. (Author)

  3. Preparation and characterization of WO3/Bi3O4Cl nanocomposite and its photocatalytic behavior under visible light irradiation

    CSIR Research Space (South Africa)

    Chakraborty, AK

    2012-01-01

    Full Text Available The highly efficient and visible light ( = 420 nm) responsive composite photocatalyst WO3/Bi3O4Cl was prepared by the simple incipient wetness method. The heterojunction structure WO3/Bi3O4Cl demonstrated notably higher photocatalytic activity than...

  4. Plasmodium falciparum parasites expressing pregnancy-specific variant surface antigens adhere strongly to the choriocarcinoma cell line BeWo

    DEFF Research Database (Denmark)

    Haase, Rikke N; Megnekou, Rosette; Lundquist, Maja;

    2006-01-01

    Placenta-sequestering Plasmodium falciparum parasites causing pregnancy-associated malaria express pregnancy-specific variant surface antigens (VSA(PAM)). We report here that VSA(PAM)-expressing patient isolates adhere strongly to the choriocarcinoma cell line BeWo and that the BeWo line can...

  5. Facile hydrothermal synthesis of TiO2-Bi2WO6 hollow superstructures with excellent photocatalysis and recycle properties.

    Science.gov (United States)

    Hou, Ya-Fei; Liu, Shu-Juan; Zhang, Jing-huai; Cheng, Xiao; Wang, You

    2014-01-21

    One-dimensional mesoporous TiO2-Bi2WO6 hollow superstructures are prepared using a hydrothermal method and their photocatalysis and recycle properties are investigated. Experimental results indicate that anatase TiO2 nanoparticles are coupled with hierarchical Bi2WO6 hollow tubes on their surfaces. The TiO2-Bi2WO6 structure has a mesoporous wall and the pores in the wall are on average 21 nm. The hierarchical TiO2-Bi2WO6 heterostructures exhibit the highest photocatalytic activity in comparison with P25, pure Bi2WO6 hollow tube and mechanical mixture of Bi2WO6 tube and TiO2 nanoparticle in the degradation of rhodamine B (RhB) under simulated sunlight irradiation. The as-prepared TiO2-Bi2WO6 heterostructures can be easily recycled through sedimentation and they retains their high photocatalytic activity during the cycling use in the simulated sunlight-driving photodegradation process of RhB. The prepared mesoporous TiO2-Bi2WO6 with hollow superstructure is therefore a promising candidate material for water decontamination use.

  6. Physical properties characterization of WO{sub 3} films grown by hot-filament metal oxide deposition

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Reyes, J., E-mail: jdiazr2001@yahoo.com [Centro de Investigacion en Biotecnologia Aplicada del Instituto Politecnico Nacional, Ex-Hacienda de San Juan Molino, Km. 1.5, Tepetitla, Tlaxcala, 90700 (Mexico); Delgado-Macuil, R.J. [Centro de Investigacion en Biotecnologia Aplicada del Instituto Politecnico Nacional, Ex-Hacienda de San Juan Molino, Km. 1.5, Tepetitla, Tlaxcala, 90700 (Mexico); Dorantes-Garcia, V. [Preparatoria ' Simon Bolivar' de la Benemerita Universidad Autonoma de Puebla, 4 Oriente 408, Col. Centro, Atlixco, Puebla, C. P. 74200 (Mexico); Perez-Benitez, A. [Facultad de Ciencias Quimicas de la Benemerita Universidad Autonoma Puebla, 14 Sur y Av. San Claudio, Col. San Manuel, Puebla, Puebla, C. P. 72570 (Mexico); Balderas-Lopez, J.A. [Unidad Profesional Interdisciplinaria de Biotecnologia del Instituto Politecnico Nacional, Avenida Acueducto S/N, Col. Barrio la Laguna, Ticoman, Del. Gustavo A. Madero, Mexico, D.F. 07340 (Mexico); Ariza-Ortega, J.A. [Centro de Investigacion en Biotecnologia Aplicada del Instituto Politecnico Nacional, Ex-Hacienda de San Juan Molino, Km. 1.5, Tepetitla, Tlaxcala, 90700 (Mexico)

    2010-10-25

    WO{sub 3} is grown by hot-filament metal oxide deposition (HFMOD) technique under atmospheric pressure and an oxygen atmosphere. By X-ray diffraction obtains that WO{sub 3} presents mainly monoclinic crystalline phase. The chemical stoichiometry is obtained by X-ray Photoelectron Spectroscopy (XPS). The IR spectrum of the as-grown WO{sub 3} presents broad peaks in the range of 1100 to 3600 cm{sup -1}. A broad band in the 2200 to 3600 cm{sup -1} region and the peaks sited at 1645 and 1432 cm{sup -1} are well resolved, which are originated from moisture and are assigned to {nu}(OH) and {delta}(OH) modes of adsorbed water and the corresponding tungsten oxide vibrations are in infrared region from 400 to 1453 cm{sup -1} and around 3492 cm{sup -1}, which correspond to tungsten-oxygen (W-O) stretching, bending and lattice modes. The Raman spectrum shows intense peaks at 801, 710, 262 and 61 cm{sup -1} that are typical Raman peaks of crystalline WO{sub 3} (m-phase) that correspond to stretching vibrations of the bridging oxygen, which are assigned to W-O stretching ({nu}) and W-O bending ({delta}) modes, respectively. By transmittance measurements obtains that the WO{sub 3} band gap can be varied from 2.92 to 3.13 eV in the investigated annealing temperature range.

  7. The band structure of WO3 and non-rigid-band behaviour in Na0.67WO3 derived from soft x-ray spectroscopy and density functional theory.

    Science.gov (United States)

    Chen, B; Laverock, J; Piper, L F J; Preston, A R H; Cho, S W; DeMasi, A; Smith, K E; Scanlon, D O; Watson, G W; Egdell, R G; Glans, P-A; Guo, J-H

    2013-04-24

    The electronic structure of single-crystal WO3 and Na0.67WO3 (a sodium-tungsten bronze) has been measured using soft x-ray absorption and resonant soft x-ray emission oxygen K-edge spectroscopies. The spectral features show clear differences in energy and intensity between WO3 and Na0.67WO3. The x-ray emission spectrum of metallic Na0.67WO3 terminates in a distinct Fermi edge. The rigid-band model fails to explain the electronic structure of Na0.67WO3 in terms of a simple addition of electrons to the conduction band of WO3. Instead, Na bonding and Na 3s-O 2p hybridization need to be considered for the sodium-tungsten bronze, along with occupation of the bottom of the conduction band. Furthermore, the anisotropy in the band structure of monoclinic γ-WO3 revealed by the experimental spectra with orbital-resolved geometry is explained via density functional theory calculations. For γ-WO3 itself, good agreement is found between the experimental O K-edge spectra and the theoretical partial density of states of O 2p orbitals. Indirect and direct bandgaps of insulating WO3 are determined from extrapolating separations between spectral leading edges and accounting for the core-hole energy shift in the absorption process. The O 2p non-bonding states show upward band dispersion as a function of incident photon energy for both compounds, which is explained using the calculated band structure and experimental geometry.

  8. Preparation, structures and photoluminescent enhancement effect of PbWO4-TiO2 composite nanofilms

    Science.gov (United States)

    Run-Ping, Jia; Guo-Xin, Zhang; Qing-Sheng, Wu

    2006-12-01

    A novel route for preparing PbWO4-TiO2 nanofilms on a glass substrate is firstly proposed. The collodion is used as a dispersant and film-forming agent. The nanofilms are characterized through SEM, XRD, TG/DTA, PL and IR, respectively. The results of XRD indicate PbWO4 particles with tetragonal scheelite structure and TiO2 particles with Anatase phase, and SEM shows they are well dispersed in the substrate. Compared with nanoparticles, when TiO2 nanoparticles are added in 5% ratio, the PL intensities at 395 nm of PbWO4 nanofilms are enhanced obviously. IR spectrum reveals a large absorption band between 750 and 870 cm-1, which is the W-O stretching vibration in WO4 tetrahedron.

  9. Magnetic properties of KRE(WO{sub 4}){sub 2} (RE=Gd, Yb, Tm) single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Borowiec, M.T., E-mail: borow@ifpan.edu.p [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL 02-668 Warsaw (Poland); Zayarnyuk, T. [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL 02-668 Warsaw (Poland); Pujol, M.C.; Aguilo, M.; Diaz, F. [Fisica i Cristal.lografia de Materials i Nanomaterials (FiCMA-FICNA), Departament de Quimica Fisica i Inorganica, Universitat Rovira i Virgili (URV), Campus Sescelades, C/Marcel.li Domingo, s/n, E-43007 Tarragona, Catalunya (Spain); Zubov, E.E.; Prokhorov, A.D. [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL 02-668 Warsaw (Poland); Donetsk Institute for Physics and Engineering, National Academy of Sciences of Ukraine, R. Luxemburg Street 72, 83114 Donetsk (Ukraine); Berkowski, M.; Domuchowski, W.; Wisniewski, A.; Puzniak, R.; Pietosa, J. [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL 02-668 Warsaw (Poland); Dyakonov, V.P. [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL 02-668 Warsaw (Poland); Donetsk Institute for Physics and Engineering, National Academy of Sciences of Ukraine, R. Luxemburg Street 72, 83114 Donetsk (Ukraine); Baranski, M.; Szymczak, H. [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL 02-668 Warsaw (Poland)

    2010-12-01

    Magnetic properties of KGd(WO{sub 4}){sub 2}, KYb(WO{sub 4}){sub 2} and KTm(WO{sub 4}){sub 2} single crystals have been studied. Temperature and field dependences of the magnetization along the main magnetic axes and angular dependence of the magnetization in the planes settled on the magnetic axes were recorded in the temperature range from 2 up to 100 K and in magnetic field up to 9 T. Paramagnetic Curie temperatures, g-factors and exchange interaction parameters were determined. Different theoretical models were used to describe magnetic properties of KGd(WO{sub 4}){sub 2} and KYb(WO{sub 4}){sub 2} crystals.

  10. Facile Preparation of Efficient WO3 Photocatalysts Based on Surface Modification

    Directory of Open Access Journals (Sweden)

    Min Liu

    2015-01-01

    Full Text Available Tungsten trioxide (WO3 was surface modified with Cu(II nanoclusters and titanium dioxide (TiO2 nanopowders by using a simple impregnation method followed by a physical combining method. The obtained nanocomposites were studied by scanning electron microscope, X-ray photoelectron spectroscopy spectra, UV-visible light spectra, and photoluminescence, respectively. Although the photocatalytic activity of WO3 was negligible under visible light irradiation, the visible light photocatalytic activity of WO3 was drastically enhanced by surface modification of Cu(II nanoclusters and TiO2 nanopowders. The enhanced photocatalytic activity is due to the efficient charge separation by TiO2 and Cu(II nanoclusters functioning as cocatalysts on the surface. Thus, this simple strategy provides a facile route to prepare efficient visible-light-active photocatalysts for practical application.

  11. Celdas solares fotoelectroquímicas basadas en Bi2WO6

    Directory of Open Access Journals (Sweden)

    Lorean Madriz

    2014-04-01

    Full Text Available In this study, photoelectrochemical solar cells based on bismuth tungstate electrodes were evaluated. Bi2WO6 was synthesized by a hydrothermal method and characterized by scanning electron microscopy, UV-Vis reflectance spectroscopy, and X-ray powder diffraction. For comparison, solar cells based on TiO2 semiconductor electrodes were evaluated. Photoelectrochemical response of Grätzel-type solar cells based on these semiconductors and their corresponding sensitization with two inexpensive phthalocyanines dyes were determined. Bi2WO6-based solar cells presented higher values of photocurrent and efficiency than those obtained with TiO2 electrodes, even without sensitization. These results portray solar cells based on Bi2WO6 as promising devices for solar energy conversion owing to lower cost of production and ease of acquisition.

  12. Understanding the Potential of WO3 Based Sensors for Breath Analysis

    Science.gov (United States)

    Staerz, Anna; Weimar, Udo; Barsan, Nicolae

    2016-01-01

    Tungsten trioxide is the second most commonly used semiconducting metal oxide in gas sensors. Semiconducting metal oxide (SMOX)-based sensors are small, robust, inexpensive and sensitive, making them highly attractive for handheld portable medical diagnostic detectors. WO3 is reported to show high sensor responses to several biomarkers found in breath, e.g., acetone, ammonia, carbon monoxide, hydrogen sulfide, toluene, and nitric oxide. Modern material science allows WO3 samples to be tailored to address certain sensing needs. Utilizing recent advances in breath sampling it will be possible in the future to test WO3-based sensors in application conditions and to compare the sensing results to those obtained using more expensive analytical methods. PMID:27801881

  13. Anomalous spin state of Fe in double perovskite oxide Sr 2FeWO 6

    Science.gov (United States)

    Kawanaka, H.; Hase, I.; Toyama, S.; Nishihara, Y.

    2000-07-01

    In the series of Sr 2FeTO 6 (T=4d or 5d), the valence of Fe is 3+ in most of the compounds. However, recently we have found that the Sr 2FeWO 6 has Fe 2+ state. Sr 2FeWO 6 is an insulator with an antiferromagnetic transition temperature of 37 K. From the Mössbauer experiment, below ∼20 K, a center shift of +1.2 mm/ s relative to metallic iron and a quadrupole splitting of 1.9 mm/ s are obtained. The quadrupole splitting has strong temperature dependence. The hyperfine field is ∼110 kOe which seems to be quite small. We concluded that the iron ground state of Sr 2FeWO 6 is Fe 2+ high-spin ( S=2) state.

  14. ZnWO_4 crystals as detectors for double beta decay and dark matter experiments

    CERN Document Server

    Danevich, F A; Nagorny, S S; Poda, D V; Tretyak, V I; Yurchenko, S S; Zdesenko, Y G; Zdesenko, Yu.G.

    2004-01-01

    Energy resolution, alpha/beta ratio, and the pulse shape discrimination ability of the ZnWO_4 crystal scintillators were studied. The radioactive contamination of a ZnWO_4 crystal was investigated in the Solotvina Underground Laboratory. Possibilities to apply ZnWO_4 crystals for the dark matter and double beta decay searches are discussed. New improved half-life limits on double beta decay in zinc isotopes were established, in particular, for EC\\beta^+ decay of 64-Zn as: T_1/2^2nu > 8.9 10^18 yr and T_1/2^0nu > 3.6 10^18 yr, both at 68% CL.

  15. ZnWO{sub 4} crystals as detectors for 2{beta} decay and dark matter experiments

    Energy Technology Data Exchange (ETDEWEB)

    Danevich, F.A. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine)]. E-mail: danevich@kinr.kiev.ua; Kobychev, V.V. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Nagorny, S.S. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Poda, D.V. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Tretyak, V.I. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Yurchenko, S.S. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Zdesenko, Yu.G. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine)

    2005-06-01

    Energy resolution, {alpha}/{beta} ratio, and the pulse shape discrimination ability of the ZnWO{sub 4} crystal scintillators were studied. The radioactive contamination of a ZnWO{sub 4} crystal was investigated in the Solotvina Underground Laboratory. Possibilities to apply ZnWO{sub 4} crystals for the dark matter and double beta decay searches are discussed. New improved half-life limits on double beta decay in zinc isotopes were established, in particular, for -bar {beta}{sup +} decay of {sup 64}Zn as: T{sub 1/2}{sup 2{nu}}>=8.9x10{sup 18} years and T{sub 1/2}{sup 0{nu}}>=3.6x10{sup 18} years, both at 68% CL.

  16. Metal-insulator transition in Na{sub x}WO{sub 3}: Photoemission spectromicroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Sanhita, E-mail: raj@iiserkol.ac.in; Ghosh, Anirudha, E-mail: raj@iiserkol.ac.in; Raj, Satyabrata, E-mail: raj@iiserkol.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research - Kolkata, Mohanpur Campus, Nadia -741252, West Bengal (India)

    2014-04-24

    We have investigated the validity of percolation model, which is quite often invoked to explain the metal-insulator transition in sodium tungsten bronzes, Na{sub x}WO{sub 3} by photoelectron spectromicroscopy. The spatially resolved direct spectromicroscopic probing on both the insulating and metallic phases of high quality single crystals of Na{sub x}WO{sub 3} reveals the absence of any microscopic inhomogeneities embedded in the system within the experimental limit. Neither any metallic domains in the insulating host nor any insulating domains in the metallic host have been found to support the validity of percolation model to explain the metal-insulator transition in Na{sub x}WO{sub 3}.

  17. Radiation-induced color centers in La-doped PbWO sub 4 crystals

    CERN Document Server

    Deng, Q; Zhu, R Y

    1999-01-01

    This report presents the result of a study on radiation-induced color center densities in La-doped lead tungstate (PbWO sub 4) crystals. The creation and annihilation constants of radiation-induced color centers were determined by using transmittance data measured for a PbWO sub 4 sample before and during sup 6 sup 0 Co gamma-ray irradiation at a dose rate of 15 rad/h. Following a model of color center kinetics, these constants were used to calculate color center densities under irradiations at 100 rad/h. The result was found to be in good agreement with experimental data, indicating that the behaviour of PbWO sub 4 crystals under irradiation can be predicted according to this model.

  18. Sunlight driven photocatalytic water splitting using nanostructured bismuth tungstate (Bi2WO6)

    Science.gov (United States)

    Radha, R.; Sakar, M.; Bharathkumar, S.; Balakumar, S.

    2017-05-01

    Sunlight driven photocatalytic water splitting properties of nanosized Bi2WO6 have been demonstrated. Upon the structural confirmation using XRD and Raman studies, the band edge offset deduced from UV-DRS spectra showed that the energy band structure of Bi2WO6 is manifested due to electronic transition in the hybridized orbital of Bi6s and O2p to the W5d orbital. The observed Bi2WO6 nanoparticulates-assisted H2 generation from glycerol-water mixture may be attributed to the following two competitive phenomena: (i) the photocatalytic degradation of glycerol and (ii) photocatalytic splitting of water molecules, where glycerol acts as a sacrificial agent. This study sheds lights on the photocatalytic reformation of contaminated aqueous ecosystems as a green resource to produce hydrogen energy.

  19. Luminescence spectroscopy of K3WO3F3 oxyfluoride crystals

    Science.gov (United States)

    Kozlov, A. V.; Pustovarov, V. A.

    2016-09-01

    Spectra of photoluminescence (PL) in region of 1.5-5.5 eV, PL excitation spectra (3-22 eV), PL decay kinetics, the temperature dependence of the PL were measured for single crystals and ceramics K3WO3F3 as well as irradiate ceramics K3WO3F3. Synchrotron radiation was used for low temperature PL experiments with time resolution. Single crystals are transparent in microwave, visible and near UV range, inter-band transition energy is Eg = 4.3 eV. The intrinsic luminescence of tungstates is usually ascribed to the radiative relaxation of exciton-like excitations localized on WO6 octahedra or WO4 tetrahedra. In K3WO3F3 the wide band luminescence in the region of 2.5 eV with the Stokes shift of 1.5 eV with the microsecond decay kinetics is connected with luminescence of triplet self-trapped excitons (STE). This luminescence is formed by electronic transitions in [WO3F3] octahedron. Different distortion of KWOF crystal lattice is manifested in the change of the Stokes shift of STE luminescence band. The 3.2 eV emission band in low-temperature PL spectrum with decay times of 1.8 ns and 11 ns corresponds to singlet STE luminescence. A new 2.9 eV emission band is discovered in low-temperature PL spectrum in the samples irradiated by fast electrons (E = 10 MeV, D = 160 kGy). This emission band is excited not intracenter mechanism, and through the creation of excitons bound on the defects. It is suggested that it is F-like centers of anionic sublattice induced by the mechanism of elastic collision.

  20. The choriocarcinoma cell line BeWo: syncytial fusion and expression of syncytium-specific proteins.

    Science.gov (United States)

    Orendi, Kristina; Gauster, Martin; Moser, Gerit; Meiri, Hamutal; Huppertz, Berthold

    2010-11-01

    Fusion of the trophoblast-derived choriocarcinoma cell line BeWo can be triggered by forskolin. BeWo cells are regularly used as a cell culture model to mimic in vivo syncytialisation of placental villous trophoblast. The β subunit of human chorionic gonadotropin (CGB), placental alkaline phosphatase as well as placental protein 13 (PP13, LGALS13) are exclusively expressed in the syncytiotrophoblast of the human placenta, and CGB is commonly used as a marker of syncytial differentiation. Here we tested the hypothesis that syncytial fusion precedes CGB and LGALS13 expression in trophoblast-derived BeWo cells. BeWo cells were cultured for 48 h in the presence or absence of forskolin and varying concentrations of H-89, a protein kinase A inhibitor that interferes with the forskolin-mediated pathway of syncytial fusion. LGALS13 and CGB expression were quantified by DELFIA and real-time PCR. Cell fusion was determined by morphological analysis and cell counting after immunofluorescence staining. In forskolin-stimulated BeWo cells that were hindered to fuse by treatment with H-89, levels of CGB protein expression were not altered, while LGALS13 protein and mRNA expression decreased significantly to control levels without forskolin. The LGALS13 protein expression data coincided with a significant decrease in syncytial fusion, while CGB protein expression was unaffected by rates of cell fusion and proliferation. We postulate that CGB protein expression is not necessarily linked to syncytial fusion, and thus CGB should be used with great caution as a marker of BeWo cell fusion.

  1. Humidity sensing properties of WO{sub 3} thick film resistor prepared by screen printing technique

    Energy Technology Data Exchange (ETDEWEB)

    Garde, Arun S, E-mail: arungarde@yahoo.co.in

    2014-12-25

    Highlights: • Polycrystalline WO{sub 3} Thick films are fabricated by screen printing technique. • Monoclinic phases were the majority in formation of films. • The peak at 1643 cm{sup −1} shows stretching vibrations attributed to W-OH of adsorbed H{sub 2}O. • Absorption peaks in the range 879–650 cm{sup −1} are attributed to the stretching W-O-W bonds. • Increase in resistance with decrease in RH when exposed to 20–100% RH. - Abstract: Thick films of tungsten oxide based were prepared using standard screen printing technique. To study the effect of temperature on the thick films were fired at different temperature for 30 min in air atmosphere. The WO{sub 3} thick films were characterized with X-ray diffraction, scanning electron microscopy and EDAX for elemental analysis. The formation of mixed phases of the film together with majority of monoclinic phase was observed. IR spectra confirm the peak at 1643 cm{sup −1} clearly shows stretching vibrations attributed to the W-OH bending vibration mode of the adsorbed water molecules. The absorption peaks in the range 879–650 cm{sup −1} are attributed to the stretching W-O-W bonds (i.e. ν [W-O{sub inter}-W]). The peak located at 983 cm{sup −1} belong to W=O terminal of cluster boundaries. A change in the resistance was observed with respect to the relative humidity when the WO{sub 3} thick films were exposed to a wide humidity range of 20–100%. An increasing firing temperature of WO{sub 3} film increases with the sensitivity. The parameters such as sensitivity and hysteresis of the WO{sub 3} film sensors have been evaluated.

  2. Hot-wire chemical vapor deposition of WO{sub 3−x} thin films of various oxygen contents

    Energy Technology Data Exchange (ETDEWEB)

    Houweling, Z. Silvester, E-mail: Silvester.Houweling@asml.com [Section Nanophotonics – Physics of Devices, Debye Institute for Nanomaterials Science, Utrecht University, Princetonlaan 4, 3584 CC Utrecht (Netherlands); Geus, John W. [Inorganic Chemistry and Catalysis, Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Schropp, Ruud E.I. [Section Nanophotonics – Physics of Devices, Debye Institute for Nanomaterials Science, Utrecht University, Princetonlaan 4, 3584 CC Utrecht (Netherlands)

    2013-06-15

    We present the synthesis of tungsten oxide (WO{sub 3−x}) thin films consisting of layers of varying oxygen content. Configurations of layered thin films comprised of W, W/WO{sub 3−x}, WO{sub 3}/W and WO{sub 3}/W/WO{sub 3−x} are obtained in a single continuous hot-wire chemical vapor deposition process using only ambient air and hydrogen. The air oxidizes resistively heated tungsten filaments and produces the tungsten oxide species, which deposit on a substrate and are subsequently reduced by the hydrogen. The reduction of tungsten oxides to oxides of lower oxygen content (suboxides) depends on the local water vapor pressure and temperature. In this work, the substrate temperature is either below 250 °C or is kept at 750 °C. A number of films are synthesized using a combined air/hydrogen flow at various total process pressures. Rutherford backscattering spectrometry is employed to measure the number of tungsten and oxygen atoms deposited, revealing the average atomic compositions and the oxygen profiles of the films. High-resolution scanning electron microscopy is performed to measure the physical thicknesses and display the internal morphologies of the films. The chemical structure and crystallinity are investigated with Raman spectroscopy and X-ray diffraction, respectively. - Highlights: • Synthesis of tungsten oxide thin films of controllable oxygen content. • Partial reduction of WO{sub 3−x} thin films during deposition. • Deposition of layered films with configurations of W, W/WO{sub 3−x}, WO{sub 3}/W/WO{sub 3−x}. • Synthesis of WO{sub 3−x} films with atomic oxygen-to-tungsten ratios between 0.3 and 3.

  3. End pumped yellow laser performance of Dy3+:ZnWO4

    Science.gov (United States)

    Xia, Zhongchao; Yang, Fugui; Qiao, Liang; Yan, Fengpo

    2017-03-01

    We report an end pumped single transverse-mode (TEM00) yellow laser based on Dy3+:ZnWO4 crystal. The pump light is InGaN blue laser diode at 450 nm with the maximum power of 1.5 W. A 3 cm length Dy3+:ZnWO4 crystal served as the gain medium. By way of the square filter, we discuss the TEM00 properties. In continuous-wave operation and single transverse-mode, a maximum output power of 0.110 W and a slope efficiency of 13.0% are achieved at an emission wavelength of 575 nm.

  4. Development of W/O Microemulsion for Transdermal Delivery of Iodide Ions

    OpenAIRE

    Lou, Hao; Qiu, Ni; Crill, Catherine; Helms, Richard; Almoazen, Hassan

    2012-01-01

    The objective of this study was to develop a water-in-oil (w/o) microemulsion which can be utilized as a transdermal delivery for iodide ions. Several w/o microemulsion formulations were prepared utilizing Span 20, ethanol, Capryol 90®, and water. The selected formulations had 5%, 10%, 15%, 20%, and a maximum of 23% w/w water content. Potassium iodide (KI) was incorporated in all formulations at 5% w/v. Physicochemical characterizations were conducted to evaluate the structure and stability. ...

  5. An ab initio study of WO sub 3 under pressure up to 30 GPa

    CERN Document Server

    Pagnier, T

    2003-01-01

    High-pressure polymorphs of WO sub 3 have been studied with a first-principles pseudopotential method. The medium-range (0.01-20 GPa) and high-range (20-30 GPa) polymorphs have been characterized and are compared with recent experimental results. The main new feature is the appearance of a sevenfold coordinated tungsten in the high-pressure polymorph. The subtle phase transitions that were induced from Raman spectra evolutions have not been confirmed. However, changes in the W-O distances and O-W-O and W-O-W angles may explain the changes in Raman spectra.

  6. Study on defects associated with interstitial oxygen in PbWO4 crystal

    Institute of Scientific and Technical Information of China (English)

    Liu Feng-song; Gu Mu; Zhang Rui

    2004-01-01

    The defects associated with interstitial oxygen in lead tungstate crystals (PbWO4) are investigated by the relativistic self-consistent discrete variational embedded cluster method. The research work is focused on the density of states of interstitial oxygen defects and relational Frankel defects. The transition state method is used to calculate excitation energy of different electron orbits. Simulation results show that the existence of defects related to interstitial oxygen can diminish the bandwidth of the WO2-4 group, and it might produce the green luminescence. Frankel defects associated with interstitial oxygen could result in the absorption at 420nm.

  7. Exposure of WO3 Photoanodes to Ultraviolet Light Enhances Photoelectrochemical Water Oxidation.

    Science.gov (United States)

    Li, Tengfei; He, Jingfu; Peña, Bruno; Berlinguette, Curtis P

    2016-09-28

    Exposure of WO3 photoanodes to sustained irradiation by ultraviolet (UV) light induces a morphology change that enhances the photoelectrochemical (PEC) activity towards the oxygen evolution reaction (OER). A 30% enhancement in photocurrent density at 1.23 V vs RHE was measured despite a nominal change in onset potential. A structural and electrochemical analysis of the films before and after exposure to UV irradiation indicates that a higher film porosity and correspondingly higher specific surface area is responsible for the enhancement in PEC activity. The effect of prolonged UV irradiation on the WO3 films is fundamentally different to that which was previously observed for BiVO4 films.

  8. Structure and morphology of laser-ablated WO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, O.M.; Swapnasmitha, A.S. [Sri Venkateswara University, Department of Physics, Tirupati (India); John, J.; Pinto, R. [Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai (India)

    2005-11-01

    The structure and surface morphology of WO{sub 3} thin films deposited by a laser-ablation technique have been found to be strongly dependent on the deposition conditions and the nature of the substrate. By precisely controlling the substrate temperature and the oxygen partial pressure, amorphous, polycrystalline, nano-crystalline and iso-epitaxial WO{sub 3} thin films were successfully grown. The structure and surface morphological features of the films from X-ray diffraction and atomic force microscopy data are described in relation to the deposition conditions. (orig.)

  9. Hydrothermal preparation of WO3 nanorod arrays and their photocatalytic properties%水热法制备WO3纳米棒阵列及其光催化性能

    Institute of Scientific and Technical Information of China (English)

    郑锋; 郭敏; 张梅

    2014-01-01

    采用水热法,以 Na2 WO4·2H2 O 为原料,NaCl 为添加剂,直接在氧化铟锡透明导电基底上制备了有序 WO3纳米棒阵列。利用 X 射线衍射、扫描电子显微镜、透射电子显微镜和高分辨透射电子显微镜等手段对制备的纳米棒进行了表征,考察了pH 值对产物形貌、尺寸和取向性的影响。结果表明:单根 WO3纳米棒具有六方单晶结构,随着前驱液 pH 值的增大,平行于基底生长的 WO3纳米棒捆逐渐转变为垂直于基底生长的纳米棒阵列。另外,对制备得到的两种不同取向的 WO3纳米棒结构进行了光催化降解甲基蓝溶液的研究,发现相比于 WO3纳米棒捆结构,纳米棒阵列的光催化性能更高。%WO3 nanorod arrays were prepared on indium tin oxide ( ITO ) substrates by hydrothermal synthesis with Na2 WO4·2H2 O as a raw material and NaCl as an additive. The nanorods were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The effects of pH values on the morphology, size, and orientation of products were studied. The results show that the single crystalline WO3 nanorod is hexagonal. When the pH value of the precursor solution increases, WO3 nanorod bundles parallel to the substrate turn into nanorod arrays vertical to the substrate. In addition, two different orientation WO3 nanorod structures were investigated by photocatalytic degradation of methyl blue solutions. It is found that the photocatalytic property of WO3 nanorod arrays is better than that of WO3 nanorod bundles.

  10. Wall effect in deactivation of excited molecular oxygen {sup 1}{delta}g; Reiki sanso bunshi {sup 1}{delta}g no shikkatsu ni oyobosu hyomen hanno no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, S.; Hasegawa, Y.; Yamashita, I. [Mechanical Engineering Laboratory, Tsukuba (Japan)

    1993-10-25

    This paper discusses effects of surface reaction on deactivation of excited molecular oxygen in {sup 1}{Delta}g condition. Gaseous oxygen containing excited oxygen generated by microwave discharge at a concentration of less than 1% is flown into several kinds of tubes to be measured such as quartz tubes (with an inner diameter of about 10 mm), and the light emitting intensity of the excited oxygen was measured upstream and downstream of the tubes to be measured (with in-tube pressure of 1 Torr or 2 Torr) to derive its concentration change. The surface reaction on the tube wall was regarded as a primary reaction, and the concentration change of the excited oxygen in flows in the round tube (attributable to the surface reaction) was analyzed. With respect to effects of tube wall materials on deactivation of the excited molecular oxygen, the surface deactivation probability in the case of using low-activity materials has decreased in the order of Pyrex, PVC, quartz, PFA and PTFE. The surface deactivation probability in the case of using a metallic material, SUS316L, was about 1000 times larger than that in the quartz. 14 refs., 7 figs., 1 tab.

  11. Film condensation of HCFC-123 on in-line bundles of horizontal finned tubes. Effect of fin geometry. Suihei fin tsuki kan no gobanme kangun ni okeru HCFC-123 no gyoshuku. Fin keijo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takada, N. (Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study); Kim, K. (Kyushu University, Fukuoka (Japan)); Ishikawa, Y. (Otsuka Pharmaceutical Co. Ltd., Tokyo (Japan))

    1994-06-25

    Theoretical analysis and experiments were carried out in regard to the condensation of HCFC-123 vapor on a horizontal finned tube. The previous paper described the theoretical analysis on the film condensation in a tube nest with low-fins. In this study, approximate expressions of heat transfer coefficient for a newly proposed high-performance finned tubes are suggested and compared with the experimental results. In the test, HCFC-123 vapor was flowed from the upper part of the tube nest arranged in squares of 3 rows and 15 layers (tube pitch: 22mm), and was condensed on the tube surface. The liquid film formation was observed, and the heat transfer properties were measured. Two kinds of conventional low-fin tubes and two kinds of finned tubes of which shape is similar to the newly proposed ones were tested. One of the new finned tubes showed the highest heat transfer performance, which was about 85% higher than that of the conventional low-fin (26 fpi) tube. The theoretical model for condensation in the previous paper was correspondent with the experimental data at low vapor speed and low condensate inundation rate. 14 refs., 14 figs., 4 tabs.

  12. Film condensation of HCFC-123 on staggered bundles of horizontal finned tubes. Effect of fin geometry; Suihei fintsukikan no chidori kanbun ni okeru HCFC-123 no gyoshuku. Fin keijo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takada, N. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study; Makishi, O. [Kyushu University, Fukuoka (Japan); Sejimo, H. [NKK Corp., Tokyo (Japan)

    1995-03-25

    Experiments were conducted to obtain row-by-row heat transfer data during condensation of downward flowing HCFC-123 vapor in staggered bundles of horizontal two-dimensional fin tubes. Two conventional low fin tubes and two finned tubes with fin shapes close to that of a new high-performance fin proposed by Zhu and Honda were tested. The latter tubes had fin dimensions that were optimized by theoretical analysis. The heat transfer characteristics were compared with previous results for in-line bundles of the same test tubes and with theoretical predictions for stagnant vapor. The decrease in heat transfer due to condensate inundation was less significant for the staggered tube bundle. The highest heat transfer coefficient was provided by the staggered bundle of one of the new finned tubes. The theoretical predictions compared well with experimental data at a low vapor velocity and a low to medium condensate inundation rate. 15 refs., 10 figs., 2 tabs.

  13. Reduction of artificial source effect in the high-resolution aeromagnetic survey in the Hanshin region; Hanshin chiiki no komitsudo kuchu jiki tansa ni okeru jinko noise source no eikyo no jokyo

    Energy Technology Data Exchange (ETDEWEB)

    Nakatsuka, T.; Makino, M.; Morijiri, R.; Okuma, S. [Geological Survey of Japan, Tsukuba (Japan)

    1997-05-27

    A high-resolution aeromagnetic survey was carried out in December 1995 on areas from Kobe City to Kyoto City in relation to the Hyogoken-nanbu Earthquake in 1995. It was found in the survey that effects of electric trains driven by direct current and man-made structures cannot be avoided, working as a large noise factor in extraction and analysis of geological information. This paper describes a quantitative analysis on magnetic anomaly suspected to have been caused from artificial sources seen in the magnetic map of the Hanshin area obtained from the above exploration data. The paper also gives considerations on methods to remove the effects therefrom. It then describes a quantitative analysis and the result of attempts on removal of the anomaly, taking up the following factors: (1) distribution of specific and remarkable magnetic anomalies which correspond to railroad positions of the Hanshin Railways running through the Nishinomiya-Toyonaka area, (2) the magnetic anomaly trend in positive and negative pair seen in the seafront area of Kobe City, and (3) typical bipolar isolated type magnetic anomaly in the north-west part of Kobe City. The cause for (1) was loop current flown for the railway operation, that for (2) was man-made structures in the improved seafront area, and that for (3) was a provisionally built metal waste storage yard. 9 figs.

  14. Studies of initial stage in coal liquefaction. Effect of decomposition of oxygen-functional groups on coal liquefaction; Ekika hanno no shoki katei ni kansuru kenkyu. 3. Gansanso kannoki no bunkai kyodo to ekika hanno eno eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Komeiji, A.; Kaneko, T.; Shimazaki, K. [Nippon Brown Coal Liquefaction Co. Ltd., Tokyo (Japan)

    1996-10-28

    Pretreatment of brown coal in oil was conducted using 1-methyl naphthalene or mixture of tetralin and 1-methyl naphthalene as solvent at temperatures ranging from 300 to 430{degree}C under nitrogen atmosphere. Effects of the solvent properties on the structural change of oxygen-functional groups (OFG) and coal liquefaction were investigated by means of quantitative analysis of OFG and solid state {sup 13}C-NMR measurement. When hydrogen transfer from solvent was insufficient, it was suggested that brown coal molecules loose their hydrogen to be aromatized. While, at lower temperatures ranging from 300 to 350{degree}C, hydrogen contained in brown coal molecules was consumed for the stabilization of pyrolytic radicals, and the deterioration of liquefaction was not observed. When hydrogen transfer from solvent was insufficient at higher temperatures above 400{degree}C in nitrogen atmosphere during pretreatment in oil, crosslinking like benzofuran type was formed by dehydration condensation of hydroxyl group in brown coal, to deteriorate the liquefaction, remarkably. The addition of donor solvent like tetralin decreased the formation of crosslinking like benzofuran type, which suppressed the deterioration of liquefaction. 8 refs., 5 figs.

  15. Coliquefaction of coal, tar sand bitumen and plastic (interaction among coal, bitumen and plastic); Sekitan/tar sand bitumen/plastic no kyoekika ni okeru kyozon busshitsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H.; Okuyama, Y.; Matsubara, K. [NKK Corp., Tokyo (Japan); Kamo, T.; Sato, Y. [National Institute for Resources and Environment, Tsukuba (Japan)

    1996-10-28

    For the improvement of economy, coliquefaction of coal, tar sand bitumen and plastic was performed under low hydrogen pressure, to investigate the influence of interaction among these on the liquefaction characteristics. For comparison, coliquefaction was also performed under the hydrogen pressure same as the NEDOL process. In addition, for clarifying its reaction mechanism, coliquefaction of dibenzyl and plastic was performed as a model experiment, to illustrate the distribution of products and composition of oil, and to discuss the interaction between dibenzyl and various plastics, and between various plastics. Under direct coal liquefaction conditions, coprocessing of Tanito Harum coal, Athabasca tar sand and plastic was carried out under low hydrogen pressure with an autoclave. The observed value of oil yield was higher than the calculated value based on the values from separate liquefaction of coal and plastic, which suggested the interaction between coal and the mixed plastic. The results of coliquefaction of coal, tar sand bitumen and plastic could be explained from the obtained oil yield and its composition by the coliquefaction of dibenzyl and plastic. 2 refs., 3 tabs.

  16. Effect of coal rank and mineral matter on gasification reactivity of coal char treated at high temperature; Netsushorishita sekitan char no gas ka tokusei ni taisuru tanshu oyobi kobutsushitsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, K.; Takei, H.; Harano, A.; Takarada, T. [Gunma University, Gunma (Japan). Faculty of Engineering

    1996-10-28

    In the wide range from brown coal to anthracite, an investigation was made of effects of heat treatment on physical/chemical properties and of coal rank dependence. For the experiment, 12 kinds of coal samples were used, and for heat treatment, the fluidized bed heated by the electric furnace and the infrared-ray gold image furnace were used. To examine characteristics of the heat-treated coal char, conducted were oxygen gasification, TPD measurement, XRD measurement, alkali metal measurement, and pore distribution measurement. The following were obtained from the experiment. The gasification reaction rate of the char heat-treated in the temperature range between 900{degree}C to 1700{degree}C decreases with a rise of the temperature of heat treatment, and the degree of decrease in the rate depends on coal rank. The order of gasification rate between coal ranks depends on the temperature of heat treatment, and the lower the heat treatment temperature is, the more largely the gasification rate is influenced by catalysis of mineral matters included in the coal. As causes of the decrease in gasification rate associated with the rise in temperature of heat treatment, indicated were release of alkali metal having catalysis and decrease of active sites by carbonaceous crystallinity. 6 figs.

  17. Effect of air pollution on annual ring width of Pinus densiflora Sieb. et Zucc. and Cryptomeria Japonica D. Don, in Kitakyushu city. Kitakyushu shi deno Sugi, Akamatsu no nenrinhaba ni oyobosu taiki osen no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Y.; Yamashita, T.; Kido, K. (The Kitakyushu Municipal Inst. of Environmental Health Sciences, Kitakyushu (Japan))

    1993-05-10

    There is a little of examples to have numerically evaluated an influence of the air pollution in the field for the long period. By using the conifer species growing in the Kitakyushu city and its periphery, in this report, a relation between the annual ring width and the air pollution has been investigated. Two tree species of Pinus densiflora Sieb. et Zucc. and Cryptomeria japonica D.Don were selected as the tree species. The individuals, with a breast height diameter of about 50cm, more than 10 pieces for each were selected, and then the annual ring specimens for about 50 years upto 1990 were obtained by using the increment borer. The annual ring width was normalized by converting to the annual ring indices. It was found that there is a significant relation between the annual ring indices obtained from the trees in the city and the air pollution, and that the annual ring growth in the 1990's has recovered to a same degree of the growth in the 1940's. As a result of comparing the multiple regression in 3 cases using the air pollution statistics, meteorological statistics and both of them, in addition, it was found that, while both of the air pollution and climatic factors influence on the growth of annual ring, the influence of air pollution is greater than the climate at the stand in the city. 23 refs., 2 figs., 4 tabs.

  18. Development of environmental assessment by tree ring (1). Characteristics of tree ring width in pine tree. Jumoku nenrin ni yoru kankyo eikyo hyoka shuho no kaihatsu (1). Matsu no nenrin haba no jittai to kiso tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Shinada, Yasushi; Nashimoto, Makoto; Kobayashi, Toshimitsu.

    1988-12-01

    In order to investigate the causal relation of change in vegetation status with the power station after starting the operation, pine trees in the surrounding area were studied in tree ring characteristics. The sampling was made at six stands ranged from the Tohhoku district to the Chugoku district. Pinus densiflora and P. Thunbergii were 0.1 to 16.2mm and 0.05 to 9.05mm, respectively, in tree ring width. They were, in frequency distribution, both a logarithmic normal distribution with 1.05 to 1.50mm in mode. Their frequency distribution being a logarithmic normal distribution, along with advance in years thereafter it transfers to a normal distribution, then to a logarithmic normal distribution, then to an L-shaped distribution. Pinus densiflora and P. Thunbergii were 6.5+-3.5mm and 6.5+-2.5mm, respectively, in maximum tree ring width, of which the appearance ratio was high in trees, 4 to 12 years old. While the minimum tree ring width appears, when the tree is very young in age and in specific calendar years during its second half of life. As for the time series of tree ring width, it, small when one year old, continues to enlarge along with advance in years until about ten years old, attains the maximum and, after then, diminishes along with advance in years. 6 refs., 7 figs., 3 tabs.

  19. Influence of using plural household air coolers on the air cooling demand. Actual state survey of air coolers in use. Kateiyo eakon no fukusu hoyuka ga reibo juyo ni oyobosu eikyo. Eakon shiyo jittai chosa kara

    Energy Technology Data Exchange (ETDEWEB)

    Higashida, R. (The Institute of Energy Economics, Tokyo (Japan))

    1994-07-01

    The present rise in power peak is judged mainly attributable to the increase in household and business use energy demand particularly for air cooling. In the present investigation, the actual state of air coolers domestically used was surveyed in the afternoon (from 1200 to 1600 hours) during the last ten days of August, which survey was followed by a study of relation between the number of air coolers domestically installed and used, and their operational state. Explanation is made of the present status of household air cooling demand, questionnaire survey and sampling, actual state analysis of air coolers in use, and the trend of household air cooling demand. As a result of the survey, about 10% of the homes use simultaneously plural units of air cooler in the afternoon, while about 50% do only one unit. With an increase in number of air coolers installed, their operation rate rises. It is concluded that the room-by-room trend and potentiality of air coolers will depend upon the operation rate of household air coolers. In the long tern outlook, it is indispensable to uninterruptedly watch the future change in power peak due to that in life style such as the family composition and home structure in the society with ages advanced. 18 figs., 9 tabs.

  20. Effects of pH of the aqueous solutions on the growth of hydroxyapatite whiskers; Suisan apatite whisker no seicho ni oyobosu suiyoeki no pH no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Iizuka, T.; Nozuma, A. [NICHIAS Corporation, Shizuoka (Japan)

    1998-08-01

    In this study, the synthesis of hydroxyapatite whiskers at 90degC using solution method is carried out, and the effects of pH, mole ration of blended Ca/P and solution concentration on the growth of the whiskers are examined thus obtaining the following findings. Hydroxyapatite whisker aggregates are synthesized by adjusting a mixed solution of calcium chloride dissolved in hydrochloride acid and dipotassium hydrogenphosphate to have a pH vale of 4.4. To 5.00 and heating the same at 90degC for 24 hours. But meanwhile, monetite crystal precipitates slightly. The form of the synthesized whisker aggregate changes from spherical form to arborescent form and cone-like form with the adjustment of pH to higher values. When P concentration is 0.012M and the ratio of blended Ca/P is increased from 1.67 to 5, the initial pH of the precipitation reaction becomes lower whereas the form of the precipitate and the precipitation amount are scarcely influenced by the mole ratio of blended Ca/P. 24 refs., 5 figs.

  1. Study on turning performance of four-track steering vehicles. Effect of traction force and track speed distribution control; Sodashiki sokisha no senkai seino ni kansuru kenkyu. Kudoryoku haibun to sokudo haibun no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, M.; Watanabe, K.; Kitano, M. [National Defense Academy, Kanagawa (Japan)

    1997-10-01

    The four-track steering vehicles (4TS) is a new type of off-road vehicle which can replace four wheels with track units to improve the mobility on soft terrains. In this paper, the numerical simulations, under the various types of differential and track velocity control systems, are conducted to predict the turning performance and steer ability of the 4TS vehicles. The results of the numerical analysis demonstrate that the differential systems with realistic combined distribution control systems of the track speed is efficient at a small turning radius. 4 refs., 13 figs.

  2. Stabilizing control of continuous DTB crystallizer. Influence of undissolved fine crystals in external heater; DTB gata renzoku shosekiki no anteika seigyo. Gaibu kanetsuki ni okeru bisho kessho tokenokori no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Naito, Kiyoshi; Sotowa, Ken' ichi; Kano, Manabu; Hasebe, Shinji; Hashimoto, Iori [Kyoto University, Kyoto (Japan). Dept. of Chemical Engineering

    1999-01-10

    In the study of modeling and control of continuous DTB crystallizers, it has been common practice to assume complete dissolution of fine crystals in an external heater (fines dissolver). However, complete dissolution of fine crystals is not always guaranteed because the dissolution rate is finite. In this work, a model of an external heater is developed by taking account of the finite dissolution rate of the crystals. The model is used to study the influence of incomplete dissolution of fine crystals on the stabilizing control of the crystal size distribution (CSD). It is found to be difficult to suppress the sustained oscillation of CSD by using the conventional SISO controllers, which regulate the amount of fines crystals by manipulating the fines flow rate. This is because when the fines flow rate is very large, an increase in the fines flow rate can reduce the amount of crystal dissolution in the external heater. It is demonstrated that instability can be avoided by imposing an upper limit on the fines flow rate. Furthermore, it is shown that the upper limit can be predicted by using the results of open-loop simulation. (author)

  3. Fiscal 1998 research report on the basic study on the effect of microgravity on living individuals; Bisho juryoku no seibutsu kotai ni taisuru eikyo no kiso kenkyu 1998 nendo chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    In order to clarify the effect of microgravity on vital functions and organisms at a cell level, this research studies the molecular biological response function of higher animals, the gravity acceptable mechanism of single-cell organisms, the effect of gravity on geotaxis of insects, measurement of monoamine system neurotransmitters of rat hippocampus by dialysis in a brain and the effect of microgravity on it, the effect of microgravity on water and bone metabolism functions and immunity function, and the analysis of BZ reaction as a simple model of vital reaction. The themes of the research are as follows: the effect of microgravity environment on cell fusion, the analysis of gravity acceptable mechanisms of single-cell organisms, the effect of oriental medical treatment on bone metabolism anomaly of mouses under microgravity environment, the effect of oriental medical treatment on change in physiological function under microgravity environment, the effect of microgravity environment on immunity systems, the effect of gravity on cell activities, the effect of a gravity field on chemical oscillation reaction, and the effect of gravity on geotaxis of insects. (NEDO)

  4. Effects of inhalation of and exposure to gaseous substances to genital organs, and sexual difference. (6). Gas jo busshitsu kyunyu bakuro ni yoru seishokuki eno eikyo oyobi seisa. (6)

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, N.; Mori, K.; Fujishiro, K.; Hori, H. (Univ. of Occupational and Environmental Health, Kitakyushu (Japan). Institute of Industrial Ecological Science)

    1991-01-01

    Results of studies and knowledges therefrom are reported on intermediate materials used in the chemical industry and ethylene oxide used as a sterilizer for medical devices as to how their toxicity affects the different sexes and feminine genital organs. Male and female rats were subjected to inhalation of and exposure to ethylene oxide at a concentration of 250 ppm 6 hours a day, 5 days a week for 17 weeks (some of them for 10 weeks), and chronic toxicity of ethylene oxide was investigated on sexual difference and female genital organs. The female rats showed their estrous cycle extended, and an increase in ratio of the estrous periods accounting for in the entire cycles was idenfified. While no sexual difference was identified in the degree of disorders in peripheral nervous system, strong macrocytic normochromia anemia was observed in female rats. Activity of glutathione reductase in ovaries has decreased, and an increase in glutathione-S-transferase activity was observed. It was made clear from these facts that ethylene oxide affected also female genital organs. 15 refs., 7 figs., 10 tabs.

  5. Effect of curing by products coating on localized heat generation and dielectric breakdown in low-density polyethylene film; Teimitsudo poriechiren firumu no kyokusho hatsunetsu to zetsuen hakai ni oyobosu kakyozai bunkai zansa tofu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Tsurimoto, T.; Nagao, M.; Kosaki, M. [Toyohashi Univ. of Technology, Aici (Japan); Mizuno, Y. [Nagoya Inst. of Technology, Nagoya (Japan)

    1996-08-20

    Polyethylene is used widely as electrical insulating materials for electric power cables, while the heat-resistance and mechanical properties of low-density polyethylene are problematic since the crystal melting point thereof is around 105 to 110{degree}C. In this paper, curing by-products such as acetophenone are coated on the surface of low-density polyethylene film specimens to make the same diffusing into said specimen, and the effects thereof on localized heat generation and dielectric breakdown are examined. The following matters are clarified by the results of this study. Under dc voltage application, the increasing of temperature is observable in lower electrical field and more remarkable localized heat generation can be found simultaneously with the decrease of breakdown strength in said specimens compared with an un-coated specimen. Especially in acetophenone-coated specimen, dielectric breakdown strength is decreased to about half. Under ac voltage application, localized heat generation is increased and breakdown strength is decreased somewhat. 14 refs., 10 figs., 1 tab.

  6. Effect of graphite nodule count and Mn content on successive austempering process of austempered ductile iron; ADI no chikuji austemper ho ni oyobosu kokuen tsubusu to Mn ryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Oide, T.; Ahmadabadi, M.; Saito, M. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1995-02-25

    Shock test was executed for a test piece where the combination of a wide range of austempering conditions was selected and the effective graphite nodule count in the successive austempering process method, the range of Mn amount, etc. were discussed. The low and high graphite nodule counts of sample were 82 - 114 and 229 - 364 piece/mm{sup 2}, respectively. The low and high Mn were 0.26 - 0.65 % and 0.96 - 1.05 %, respectively. The heat treatment cycle was retained to be 1173K, 648K, and 588K in argon gas atmosphere. The Sharpy shock test and organization observation were performed for each test piece, thus revealing that a higher toughness value than that obtained by normal treatment could be obtained by the HLAT method; the better the graphite nodulation count was, the higher the toughness was; it was effective that the Mn was approximately 0.6 %; the influence given to the shock energy value was extremely larger by residual austenite volume than the untransformed austenite module. 7 refs., 12 figs., 2 tabs.

  7. Effect of leisure orientation on fuel consumption of cars. Survey of the actual state of travel of privately owned cars; Reja shiko ga joyosha no nenryo shohi ni oyobosu eikyo. Jikayo joyosha no soko jittai chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    The actual state of car travel was surveyed to know an effect of leisure orientation on fuel consumption of cars. An questionnaire survey was conducted in Chiba city where the number of cars privately owned is close to the national average. The average annual travel distance per car used at leisure is 4200km, 43% of the total travel distance. The travel distance at leisure of a recreational vehicle (RV), especially, is about 1800km/year longer than that of the other cars. In a single household, 58% of the total travel distance are for leisure. In a household including a couple and preschoolers or a couple and school children, dependence on the car use at leisure is large, but the travel distance itself is short. In a household including a couple and college students or a couple and working members of society, children become drivers, and the distance at leisure gets as long as in a single household. Cars of the head of household are much used at leisure and those of children are used sometimes. The travel distance at leisure of cars of spouses is short. In the enhancing leisure orientation, the rate of travel for leisure will increase in the background of convenience of cars. 68 figs., 10 tabs.

  8. Effects of the pre-transformation microstructures on the grain refining of medium-carbon 5Cr-Mo-V steels; Chutanso 5Cr-Mo-V ko no gyaku hentai sairyuka ni oyobosu zenhentai soshiki no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Mukauda, Y.; Shibata, T.; Ono, S.; Ishiguro, T. [Nippon Steel Works, Ltd., Tokyo (Japan)

    2000-07-01

    For the purpose of obtaining refined grains over full cross section for improved ductility in heavy-gage products of a medium carbon 5Cr- Mo-V steel, the effects of pre-transformation microstructures on the grain refining during austenitizing were investigated. Samples were prepared to possess either one of three different microstructures , pearlite, bainite and martensite. These samples were heated slowly to the desired austenitizing temperature followed by rapid cooling, and the formation of new austenite grains was examined. Though austenite grains were not refined in cases of martensite and bainite microstructures, these were remarkably refined in case of pearlite. Portions of pearlite were enriched with carbon, where the transformation temperature into austenite was lower, and this is considered to be the reason that finer austenite grains were formed.Above results show that arranging pearlite microstructure before quenching heat treatment is effective for obtaining refined grains over full cross section in heavy-gage products. (author)

  9. Effect of VN precipitates on formation of grain boundary and intragranular ferrite in a high N-V bearing steel; V-N tenkako no ryukai oyobi ryunai ferrite hentai ni oyobosu austenite chu no VN sekishutsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Omori, A.; Oi, K.; Kawabata, F.; Amano, K. [Kawasaki Steel Corp., Tokyo (Japan)

    1998-11-01

    The enhancement of ferrite nucleation owing to vanadium nitride (VN) precipitated in the austenite phase was studied for a 0.14%C- 1.45%Mn-0.06%V-0.009%N steel and the isothermal ferrite transformation behavior associated with VN precipitation was also quantitatively discussed. Vanadium nitrides precipitate on the austenite grain boundary in preference to the grain interior and increase the density of grain boundary ferrites. On the other hand, VN precipitates in austenite grain interior are less effective to intragranular ferrite nucleation. The calculation based on the classical nucleation theory shows that the activation energy of VN precipitates for a critical ferrite nucleus formation is one-fifth lower than that in case of no precipitate. The ferrite nucleation potency of VN precipitates is kept high even in higher temperature range above 700degreeC. (author)

  10. Effect of NbC particles on {gamma}{yields}{epsilon} Martensitic transformation in Fe-22mass%Mn alloys; Fe-22 mass % Mn gokin no {gamma}{yields}{epsilon} marutensaito hentai ni oyobosu NbC ryushi no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Y.; Nakatsu, E.; Takaki, S. [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering

    1997-07-20

    The yield and transformation of epsilon ({epsilon}) martensite which is expected to be utilized as reinforcing texture of high Mn non-magnetic steel, are alternated greatly by the fining of crystal particles since said epsilon martensite is effected obviously by austenite ({gamma}) grain during the deformation in cooling process. In this study, in respect of Fe-22mass%Mn-Nb-C alloys wherein Nb and C are added to make the maximum volume rate of NbC being 1 vol%, samples wherein the size of {gamma} grains is fined to 10{mu}m or less by recrystalization are prepared, and the effect of the size of {gamma} grains and the effect of NbC particles dispersed in {gamma} grains on {epsilon} transformation are investigated. The following points are clarified by the results of said investigation. {gamma}{yields}{epsilon} transformation is suppressed remarkably by the existence of NbC particles dispersed homogeneously and finely in {gamma} grains. A large elastic stress field causing conformity deviation is formed around NbC particles by NbC particles themselves. 25 refs., 10 figs., 1 tab.

  11. Effect of strain on ferrite transformation from super-cooled austenite in Fe-0. 5%C alloy. Fe-0. 5%C gokin no karei osutenaito/feraito hentai ni oyobosu kako no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Matsuura, K.; Ito, Y.; Narita, T. (Hokkaido Univ., Sapporo (Japan). Faculty of Engineering)

    1993-08-01

    During the cooling of a steel, when austenite is applied by strain, the temperature of ferrite transformation would increase accompanied with decrease of its given temperature and increase of strain. In this study, the isothermal transformation behaviour from austenite to ferrite applied by strain in the super-cooled state was investigated, effect of strain on size of ferrite particles and increase of volume rate during transformation were explained by using the velocity theory. That is, concerning to the alloy of two-elemental system Fe-0.51%C cooled at 0.3[degree]C/s and applied by strain at 710[degree]C, at which austenite was super-cooled by 55[degree]C, its isothermal transformation behaviour was investigated. As a result, the following conclusions were obtained. Time required for the transformation remarkably decreased and the size of ferrite particles became ultra-fine subjected to strain. The nucleation rate of ferrite particles remarkably increased with increasing strain. 14 refs., 11 figs., 1 tab.

  12. Effect of austenite grain size in Fe-Mn alloys on {epsilon} martensitic transformation and their mechanical properties; Fe-Mn gokin no {epsilon} marutensaito hentai oyobi kikaiteki seishitsu ni oyobosu kessho ryukei no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Nakatsu, H. [Kyushu Univ., Fukuoka (Japan). Graduate School; Takaki, S. [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering

    1996-02-20

    The Fe-Mn two-components alloy samples varied with Mn content of 12 to 31 mass% were prepared by charging {gamma}-crystalline grain size using its recrystallization, and were surveyed on effects of the {gamma}-crystalline grain size on athermal {epsilon}-martensitic ({epsilon})-transformation and machining- induced {epsilon}-transformation. As a result of examining the relationship between the {gamma}-crystalline grain size or the {epsilon}-transformation and their mechanical properties, conclusion shown as follows is obtained. The athermal {epsilon} was formed at the alloy containing more than 10 mass% of Mn, maximum {epsilon} was shown at the composition containing about 17 mass% of Mn and the {epsilon} was almost not formed at the steel containing more than 27 mass% of Mn. When crushing the {gamma}-crystalline grain to fine powder, the {epsilon} martensitic transformation beginning temperature tended to reduce somewhat and production amount of the {epsilon} decreased extremely. On the steel containing Mn ranged 15 to 31 mass%, the fine powdering affected scarcely its durability but improved its elongation and its tensile strength. 26 refs., 11 figs., 1 tab.

  13. Effects of heating and cooling rate on transformation behaviors in weld heat affected zone of low carbon steel; Teitanso koban no yosetsu netsu eikyobu no hentai kyodo ni oyobosu kanetsu reikyaku sokudo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kanetsuki, Y.; Katsumata, M. [Kobe Steel, Ltd., Kobe (Japan)

    1998-01-25

    Discussions were given on effects of welding heat cycles on transformation behaviors in a weld heat affected zone (HAZ). Test pieces are low-carbon fine ferrite pearlite organization steel sheets, which have been treated with a thermomechanical control process (TMCP). The heat cycling was experimented at a maximum temperature of 1350 degC by using a high-frequency heating coil, heating rates from 0.15 to 200 degC/s, cooling rates from 10 to 80 degC/s at an elevated temperature region (higher than 900 degC), and transformation regions (lower than 900 degC) from 0.5 to 6 degC. A transformation curve in actual welding heat cycling was interpreted from these results. Shear-type inverse transformation (from ferrite to austenite) occurs in a rate region corresponding to the heating rate realized during welding. Austenite containing internal stress and a lower structure formed by this inverse transformation accelerates transformation into grain boundary ferrite (GBF) and acerous ferrite (AF). On the other hand, slow cooling in the elevated temperature region releases the internal stress, restores the lower structure, and suppresses the GBF and AF transformation. The GBF tends to precipitate pearlite in adjacent regions and deteriorates the HAZ tenacity. 17 refs., 8 figs., 1 tab.

  14. Effects of bainitic transformation temperature on microstructure and tensile properties of 0.6C-Si-Mn steel; 0.6C-Si-Mn ko no bisai soshiki to hippari tokusei ni oyobosu benaito hentai ondo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Y. [University of Osaka Prefecture, Osaka (Japan). Faculty of Engineering

    1995-06-15

    To acquire excellent mechanical properties of Si-Mn steel by using an austempering treatment to have the steel undergo a bainitic transformation, it is important to identify the effect of its transformation temperature. This paper describes a transformation of 0.6% C-Si-Mn steel at temperatures ranging from 593 K to 673 K, and discussions on the effect of the transformation temperature on the microstructure and tensile properties. The following results were obtained: bainitic ferrite containing very little carbon is produced in layers at any transformation temperature, but a trend was shown that the bainitic ferrite is produced with its width grown larger and denser as the transformation temperature rises; the {gamma}R amount increases remarkably with increasing transformation temperature, and at the same time massive {gamma}R begins to remain in addition to thin film {gamma}R that exists between individual bainitic ferrites; and the result of this experiment revealed that when the transformation temperature is sufficiently high, the fracture elongation increases notably because of the transformation induced plasticity (TRIP) effect of the {gamma}R that occurs effectively during the transformation. 12 refs., 7 figs., 4 tabs.

  15. Hydroelastic responses of pontoon type very large floating offshore structures. 2nd Report. Effect of the water depth and the drift forces; Pontoon gata choogata futaishiki kaiyo kozobutsu no harochu chosei oto ni kansuru kenkyu. 2. Senkai eikyo to hyoryuryoku

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, H.; Miyajima, S. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science; Masuda, K.; Ikoma, T. [Nihon University, Tokyo (Japan). College of Science and Technology

    1996-12-31

    Steady-state drift force in regular waves is theoretically analyzed. It is also studied under combined external force experimentally using a two-dimensional water tank. The fluid forces are analyzed by the pressure distribution method based on the potential theory, in which the effects of water depth are taken into account to discuss the effects of elastic deformation of the floating structure on the drift characteristics of steady-state waves. The tests were carried out using a wave-making circulating water tank equipped with a wind duct to create wind, waves and tidal flow. Drift force under a combined external force by wind, wave and/or tidal flow cannot be accurately predicted by arithmetically adding these components. For predicting drift force by tidal flow, it is necessary to take into account drag force in current at the floating structure bottom as well as that in wind at the front face. Drift force by tidal flow is affected by shallowness of water, which should be taken into account for drag forces. The floating structure will be deformed along the wave face as its stiffness decreases, basically decreasing steady-state drift force. 9 refs., 14 figs.

  16. Effect of bacteria combined with diatom on ennoblement of electrode potential for stainless in natural sea water; Shizen kaishu shu sutenresu no sizen denikika ni oyobosu bakuteria no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Yasuko.; Tsujikawa, Shigeo. [The University of Tokyo, Tokyo (Japan). School of Engineering

    1999-08-15

    When stainless steels samples are immersed in natural sea water, an ennoblement of the electrode potential (E{sub sp}) up to approximately 400 m V vs. SCE can occur, due to the development of biofilm on the samples. The main organisms in the biofilm include bacteria and deatom. In this paper it was invesigated the relationship between the ennoblement of E{sub sp} and bacteria species in the biofilm, and the interaction between bacteria and diatom in the E{sub sp} ennoblement. To study effect of various becteria species in the biofilm n the ennoblement of E{sub sp}, type 316 stainless steel samples were immersed in 0.4 {mu}m filtered natural sea water, where the filtering was expected to restrict bacteria as the only organisms in the water. Under this condition, ennoblement of E{sub sp} up to 400 m V vs. SCE could not be attained, and the need of other organisms in biofilm, becteria, to promote ennoblement was shown. The enalysis of biofilm, foemed in natural sea water, on sample with ennobled E{sub sp}, detected the presence of sulfate-reducing bacteria, acidic and neutral sulfur-oxidizing bacteria (A-SOB and N-SOB, respectively). It was also observed that the E{sub sp}, type 304 stainless steel was immersed in solutions containing Thiobacillus thioparus (as N-SOB) and T. thiooxidans (as A-SOB).Remarkable E{sub sp} ennoblement was induced by N-SOB, but not by A-SOB. However, as the density of attached N-SOB on the ennobled sample was too much higher than the density to be attained under immersion in unfiltered natural sea water, the ennoblement of E{sub sp} was concluded not to occur by that single bacteria. When samples were transferred to diatom containing solution, after immersion in natural sea water for a few days, to promote attachment of bacteria on the samples, the E{sub sp} of the samples presented high values, similar to the values observed for samples immersed in natural sea water in summer. After immersion in diatom containing solution, the effect of the density of attached bacteria and diatom on E{sub sp} was investigated. For E{sub sp} ennoblement up to 200 mV vs. SCE, the density of attached bacteria increased up to about 3.5x10{sup 4} pg/cm{sup 2}, with increasing density of diatom. For E{sub sp} ennoblement higher than 200mV vs. SCE, it is suggested that the attachment of diatom on the sample plays a more important role. (author)

  17. Effect of aluminum on the growth and nutrient uptake in cryptomeria japonica D.Don and Chamaecyparis obtusa Sieb. et Zucc.; Sugi oyobi hinoki no ikusei to yobun kyushu ni oyobosu aluminium no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kono, Y.; Matsumura, H.; Kobayashi, T. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1995-09-10

    Two-year-old seedlings of Sugi (Japanese cedar: Cryptomeria japonica D. Don) and Hinoki (Japanese cypress: Chamaecyparis obtusa Sieb. et Zucc.) were grown for 4 months in 1/5 Hoagland`s No.2 nutrient culture solution containing aluminum chloride in the concentration range of 0.5 to 20 mM within the pH range of 3.5 to 4.0. Aluminium supplied at or below 1 mM of Al had no effect on the mortality of these species. However, the increase Al concentration higher than 2 mM increased the mortality. While they showed significant growth reduction at or higher Al concentration of 5 mM, there were no difference in growth response to Al between the two species in this experiment. While Al contents in leaf and root significantly increased with increasing Al concentration in the solution, contents of Ca, Mg and P in leaf decreased. Roof p content in Sugi increased with the increase of Al concentration in the solution, while no such change was observed in Hinoki root. This result suggests that Al might make phosphate immobile or inviolable form in Sugi root and this might lead to the reduced translocation of P into the leaf. In contrast, Al did not interfere with the uptake of phosphate in the root, however, it might interrupt phosphate transport into leaf from root system in Hinoki. The Al concentration such as 5 mM in the root sphere induced growth reductions in Sugi and Hinoki, with no significant difference in the response between the two species. This concentration was much higher than those reported in the field crops, vegetables and/or herbs. Thus, if soil acidification will be induced by acidic deposition in future, these herbaceous plants will be influenced faster than the conifer trees. This also means that ground vegetation change will be observed earlier than the conifer decline by the soil acidification stress. 23 refs., 5 figs., 3 tabs.

  18. Effect of solution pH on the growth of Cryptomeria japonica and Chamaecyparis obtusa grown in nutrient solution culture; Sugi to hinoki no seiiku ni oyobosu baiyoeki pH no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kono, Y.; Matsumura, H.; Kobayashi, T. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1997-01-10

    When wet deposition including acid rain, mist and fog, and dry deposition including gaseous and particulate SOx and NOx are added to soil, the soil acidification occurs. The purpose of this study is to evaluate the soil acidification stress, which may contribute to the conifer decline. Two-year-old seedlings of Cryptomeria japonica and Chamaecyparis obtusa were cultivated to examine the effect of root sphere acidity on the plant growth in the nutrient solution culture. Acidity of one fifth Hoagland`s nutrient culture solution was adjusted to the pH in five levels, i.e., 3.5 to 4.0, 4.0 to 4.5, 4.5 to 5.0, 5.0 to 5.5, and 5.5 to 6.0. Cultivation period was for 15 weeks. The growth performance of both Cryptomeria japonica and Chamaecyparis obtusa was best under the lowest pH level of 3.5 to 4.0. Both species, however, decreased plant dry weight at high pH level. Total cation contents in the leaves and roots of both species cultivated at pH 3.5 to 4.0 were highest. These results suggested that both species have a characteristic adaptability to such a low pH condition. 13 refs., 2 figs., 3 tabs.

  19. Effects of electrode properties on transition limit to big-arcs in combustion gas plasma boundary layer. Nensho gas plasma kyokaisonai deno daidenryu kyodai arc hassei genkai ni oyobosu denkyoku bussei no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, K.; Okumura, Y. (Tokyo Institute of Technology, Tokyo (Japan)); Kokumai, M.; Yoshikawa, N. (Toyohashi University of Technology, Aichi (Japan))

    1994-05-25

    The effect of physical properties of electrode on the transition from micro-arc to big-arc in the boundary layer of combustion gas plasma such as MHD power generation, the method for preventing the occurrence of big-arc at the electrode surface side, and the possibility of small dispersion of micro-arc are experimentally investigated. The critical current for transition from micro-arc to big-arc is mainly determined by the main part temperature. It is also affected by the electrode properties. This is due to the change in arc shape caused by the heat transfer to the electrode surface and the melting and evaporation of the electrode. In the case of electrode which is likely to give rise to the abrupt gushing of metal vapor, the transition from micro-arc to big-arc is likely to occur because the boundary layer is easily broken as the momentum of the gushing vapor directed rectangularly to the electrode surface which is generating the micro-arc is large. For the prevention of transition from micro-arc to big-arc even at a large current density, it is important to select the electrode material which is characterized by high thermal conductivity, high boiling point, and high latent heat of evaporation. 17 refs., 15 figs., 1 tab.

  20. Effects of density distribution of scattering media on radiation transfer. Case of growing frost layer; Fukusha denpa ni ataeru sanransei baitai no mitsudo bunpu no eikyo. Seicho kateini aru shimoso no baai

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, A.; Washio, S. [Okayama University, Okayama (Japan); Haida, T. [NGK Insulators, Ltd., Nagoya (Japan); Matsumoto, E. [Oji Paper Co. Ltd., Tokyo (Japan)

    1999-09-25

    The main interest was taken in the effects of the density distribution on the radiation transfer in the scattering media. The frost layer in the early growth stage under the control of diffusion was chosen as the media. Numerical analysis of the radiation transfer was carried out by using a modified Monte Carlo method on the basis of the geometrical optics. A diffusion limited aggregation theory was introduced to simulate the growth of frost layer with treelike structure. The relation between the density distribution and the transmittance of the simulated model was made clear by the numerical analysis. On the basis of its result, the optical measurements in the visible wavelength region were utilized to evaluate the density distribution in the frost layer, which varied with the cooling condition, from the transmittance values. (author)

  1. Effects of free stream turbulence on turbulent boundary layer on a flat plate with zero pressure gradient. 4th Report. Calculation of flow field; Seiatsu ittei no heiban ranryu kyokaiso ni oyobosu shuryubu midare no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Hori, M.; Yata, J. [Kyoto Inst. of Technology, Kyoto (Japan); Minamiyama, T. [Fukuyama University, Hiroshima (Japan)

    1996-04-25

    The effects of free stream turbulence on turbulent boundary layer were calculated using a {kappa}-{epsilon} two-equation model. The calculations were performed with respect to velocity profiles on a flat plate wall shear stress turbulence energy integral length scales of turbulence and decay of free stream turbulence and the results were compared with experimental results. The energy of free stream turbulence and the dissipation values at the leading edge of flat plate were used, as the initial conditions for calculation. These initial values of dissipation were determined from the integral length scales of free stream turbulence at the leading edge. The calculated wall shear stress increased with the free stream turbulence and integral length scales of turbulence. The velocity profiles and turbulence energy agreed well with the experimental results and the effects of free stream turbulence on the wall shear stress agreed fairly well with those observed in experiments. 15 refs., 10 figs.

  2. Influence of shape change of impeller and scroll in the axial direction on performance and noise for multiblade blower; Tayoku sofuki no haneguruma oyobi scroll keijo no jiku hoko henka ga seino to soon ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yanazaki, S.; Hashimoto, K.; Fukasaku, Y. [Hitachi, Ltd., Tokyo (Japan)

    1997-10-25

    In this paper, the influence of shape change of the impeller and scroll in the axial direction on performance and noise are investigated. It is shown that a 14% increase in the hub-side diameter of the impeller over that of the shroud side leads to a 4% increase in the efficiency {eta}t, and a 2dB reduction in the specific sound level SLs. It is also shown that an increase in the diffusion angle of the hub side of the scroll to that of the shroud side raises the efficiency by 2%. 8 refs., 10 figs.

  3. Influence of the helical impeller and the silencer within the scroll on performance and noise for multiblade blower; Tayoku sofuki no hane herikaruka oyobi shoon kiko naizoka ga seino to soon ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, S.; Hashimoto, K.; Fukasaku, Y. [Hitachi, Ltd., Tokyo (Japan)

    1996-10-25

    In this paper, the velocity distributions around the impeller of a multiblade blower and noise reduction by the silencer within the scroll are investigated. It is shown that the region of small meridian velocity Cm2 at the outlet of the impeller is about 40% of the blade width b2 due to the inclination of the main sow to the hub. It is also shown that the velocity fluctuations at the trailing edge of a blade are about 30% of the maximum velocity and that a silencer composed of sound-absorbing fiber and an air chamber within the scroll can reduce the specific sound level SLs by 2.5 dB. 10 refs., 14 figs.

  4. Hydroelastic responses of pontoon type very large floating offshore structures. 2nd Report. Effect of the water depth and the drift forces; Pontoon gata choogata futaishiki kaiyo kozobutsu no harochu chosei oto ni kansuru kenkyu. 2. Senkai eikyo to hyoryuryoku

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, H.; Miyajima, S. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science; Masuda, K.; Ikoma, T. [Nihon University, Tokyo (Japan). College of Science and Technology

    1996-12-31

    Steady-state drift force in regular waves is theoretically analyzed. It is also studied under combined external force experimentally using a two-dimensional water tank. The fluid forces are analyzed by the pressure distribution method based on the potential theory, in which the effects of water depth are taken into account to discuss the effects of elastic deformation of the floating structure on the drift characteristics of steady-state waves. The tests were carried out using a wave-making circulating water tank equipped with a wind duct to create wind, waves and tidal flow. Drift force under a combined external force by wind, wave and/or tidal flow cannot be accurately predicted by arithmetically adding these components. For predicting drift force by tidal flow, it is necessary to take into account drag force in current at the floating structure bottom as well as that in wind at the front face. Drift force by tidal flow is affected by shallowness of water, which should be taken into account for drag forces. The floating structure will be deformed along the wave face as its stiffness decreases, basically decreasing steady-state drift force. 9 refs., 14 figs.

  5. Groundwater pollution by arsenic and its effect on health. Present state of groundwater pollution by arsenic and its environmental quality standard; Hiso ni yoru chikasui osen to kenko eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, N.

    1997-07-10

    Resorted the official data of groundwater inspections in Japan for fiscal 1995 in accordance with the new environmental quality standard (revised in 1997), the largest number of samples that exceeded the standard values among 23 inspection items of substances was of arsenic (As: standard 0.01mg/l). In this case, 49 samples out of total 2720 samples exceeded the standard values due to As (excess ratio 1.8%). The next substances having high excess ratio were four organic chlorine compounds which are widely used as detergent (excess ratio 0.6-0.1%), and next to these was lead (0.1%). About the other substances, excess was not found. The birthplaces of the above 48 samples were as follows: Fukuoka prefecture (12 samples), Chiba (19), Saitama (7), Gunma (4), Miyagi (4), Niigata (3), Hokkaido (2), Yamagata (1, the followings were also the same), Tokyo, Aichi, Osaka, Hyogo, Tottori. Recently, arsenic poisoning in Bangladesh has been reported, and the cause of it is estimated as excessive pumping up of irrigation water. In Japan, future strengthening of surveillance is expected. 2 figs., 5 tabs.

  6. Influence of carbon content on superplastic behaviour in Ti and B doped Cr-Mo steels; Ti, B tenka kuromu moribudenko no chososei ni oyobosu tanso gan`yuryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Aramaki, M.; Nakai, O.; Onodera, R.; Higashida, K. [Kyushu University, Fukuoka (Japan). Faculty of Engineering

    1997-12-01

    Superplasticity has been investigated in various ferrous alloys and steels. However, in these materials, especially in the hypoeutectoid steel bellow A1 temperature, the relationship between the content of carbon and elongation to failure is not obvious. In the present investigation, the influence of carbon content on superplastic behaviour is studied using carbon steels based on Cr-Mo steel. In order to obtain the fine grain structure, a small amount of Ti and B were added and the content of carbon was controlled to be in the range of 0.24% to 0.83%. The largest value of elongation to failure was 644% which was obtained by the tensile test of the specimen containing 0.58% carbon. The temperature and strain rate at which the maximum value was obtained were 710degC and 5 times 10{sup -4}s{sup -1}, respectively. Of all the specimens, this. specimen had the minimum grain size. Moreover, the area fraction of carbide took the maximum value at the temperature where the largest elongation value was obtained. These results show that the addition of carbon has an effect on grain refinement by formation of carbide, but excess amounts of carbons (>0.6%) bring about premature failure because of coarse microstructure and larger carbide. 17 refs., 9 figs., 1 tab.

  7. Effects on annual cost of solar/air-heat utilization system of carbon tax and interest rate for a residential house; Jutakuyo taiyo/taikinetsu riyo system no nenkan keihi ni oyobosu tansozei kinri no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Q.; Kenmoku, Y.; Sakakibara, T. [Toyohashi University of Technology, Aichi (Japan); Nakagawa, S. [Maizuru National College of Technology, Kyoto (Japan); Kawamoto, T. [Shizuoka University, Shizuoka (Japan). Faculty of Engineering

    1996-10-27

    In recent years, a system has been proposed that utilizes river heat, air-heat, exhaust heat from a cooler, etc., in addition to natural energy for the heat pump. With the introduction of such system, the amount of energy used and that of CO2 exhaust will be greatly reduced, but annual expenses will be increased as it stands. In order to improve the cost efficiency of the system, a proposal has been made for the introduction of an economic policy such as the carbon tax and a low interest financing system. With these matters in the background, the subject study predicts the production of solar cells in the future and, on the basis of this production, determines the price, conversion efficiency and equipment energy of solar cells in the future. Using these values and taking into consideration the introduction of the carbon tax and the low interest financing system, the optimum area was determined for solar cells and heat concentrators in a future residential solar/air-heat energy system. The carbon tax, being imposed on all CO2 discharges, had a large effect. Moreover, as the tax increased, annual expenses decreased for the solar/air-heat system. 3 refs., 6 figs.

  8. Effect of insolation forecasting error on reduction of electricity charges for solar hot water system; Taiyonetsu kyuto system no denki ryokin sakugen koka ni oyobosu nissharyo yosoku gosa no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, S. [Maizuru National College of Technology, Kyoto (Japan); Kenmoku, Y.; Sakakibara, T. [Toyohashi University of Technology, Aichi (Japan); Kawamoto, T. [Shizuoka University, Shizuoka (Japan)

    1996-10-27

    A solar hot water system can be economically operated if inexpensive midnight power is purchased to cover the shortage of solar energy predicted for the following day. Investigations were conducted because error in insolation prediction affects the system operation and electric charge reduction effect. The target temperature of the heat accumulation tank at every predetermined time point is calculated on the previous evening in consideration of predicted insolation so that the water will be as hot as prescribed at the feeding time on the following day. Midnight power is used for uniform heating to attain the target temperature for 7 o`clock on the following morning. The uniform heating continues from 8 o`clock to the feeding time, this time using solar energy and daytime power to attain the target temperature. Accordingly, the division between the midnight power and daytime power is determined in view of the target temperature for 7 o`clock on the following morning, which target temperature is so set that the charge will be the minimum by optimizing the allocation of the above-said two. When the insolation prediction error rate is beyond 30%, the electric charge grows higher as the rate rises. But, when the rate is not higher than 30%, the charge is little affected by a rise in the rate. 5 refs., 10 figs., 1 tab.

  9. Study of coherent optical fiber communication in electromagnetic field. 2. Optical polarization transient by impulse current in OPGW; Coherent hikaritsushin eno denjikai no eikyo to taisaku. 2. Impulse denryu ni yoru OPGW denpako no henpa hendo

    Energy Technology Data Exchange (ETDEWEB)

    Kurono, M.; Isawa, K.; Kuribara, M. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1995-03-01

    A coherent optical fiber communication method has possibility of large capacity transmission for future, but it needs a control of polarization state of optical signal. So it is important to clear the optical polarization characteristics of OPGW because the polarization state may change rapidly by alternative current or lightning. This report describes the experimental results of transient states of optical polarization and coherent transmission characteristics by large impulsive current in OPGW (200m length). The impulse current is maximum 16kA at peak and 1{times}10 us rise and tail time. Polarization states are measured by a real time stokes analyzer with 10 MHz band width. As a result, the maximum shift of polarization state on Poincare sphere is about 70 degree and the rise time is about 12us, which is much longer than current use time 1us. We found the reason that the polarization rise time is caused by the inductance of spiral current along twisted conductors of OPGW, which makes magnetic field along the fiber in OPGW so as to occur Faraday effect. The coherent optical FSK transmission characteristics in transient state of optical polarization by impulse current is also described. In the case of single detection, bit errors are caused when the polarization states of optical signal on Poincare sphere move about 150 degree from the polarization state of local optical source. And in the case of polarization diversity detection, bit error is not caused by any change of polarization. 7 refs., 31 figs., 2 tabs.

  10. TiO{sub 2} nanotubes supported NiW hydrodesulphurization catalysts: Characterization and activity

    Energy Technology Data Exchange (ETDEWEB)

    Palcheva, R., E-mail: palcheva@gmail.com [Institute of Catalysis, Bulgarian Academy of Sciences, G. Bonchev Str., Bldg. 11, 1113 Sofia (Bulgaria); Dimitrov, L. [Institute of Mineralogy and Crystallography Acad. I. Kostov, G. Bonchev Str., Bldg. 107, 1113 Sofia (Bulgaria); Tyuliev, G.; Spojakina, A. [Institute of Catalysis, Bulgarian Academy of Sciences, G. Bonchev Str., Bldg. 11, 1113 Sofia (Bulgaria); Jiratova, K. [Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, 165 02 Prague 6 (Czech Republic)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer NiW catalysts supported on TiO{sub 2} nanotubes, titania and alumina. Black-Right-Pointing-Pointer The best results are obtained with NiW/TiO{sub 2} nanotubes in hydrodesulfurization (HDS) of thiophene. Black-Right-Pointing-Pointer Active phase is Ni-WO{sub x}S{sub y}. Black-Right-Pointing-Pointer Electronic promotion of W by Ti. - Abstract: High surface area TiO{sub 2} nanotubes (Ti-NT) synthesized by alkali hydrothermal method were used as a support for NiW hydrodesulphurization catalyst. Nickel salt of 12-tungstophosphoric acid - Ni{sub 3/2}PW{sub 12}O{sub 40} was applied as oxide precursor of the active components. The catalyst was characterized by S{sub BET}, XRD, UV-vis DRS, Raman spectroscopy, XPS, TPR and HRTEM. The results obtained were compared with those for the NiW catalysts prepared over high surface area titania and alumina supports. A polytungstate phase evidenced by Raman spectroscopy was observed indicating the destruction of the initial heteropolyanion. The catalytic experiments revealed two times higher thiophene conversion on NiW catalyst supported on Ti-NT than those of catalysts supported on alumina and titania. Increased HDS activity of the NiW catalyst supported on Ti-NT could be related to a higher amount of W oxysulfide entities interacting with Ni sulfide particles as consequence of the electronic effects of the Ti-NT observed with XPS analysis.

  11. Numerical simulation and experimental study of PbWO4/EPDM and Bi2WO6/EPDM for the shielding of {\\gamma}rays

    CERN Document Server

    Song, Chi; Zhang, Quanping; Li, Yintao; Li, Yingjun; Zhou, Yuanlin

    2016-01-01

    The MCNP5 code was employed to simulate the {\\gamma}ray shielding capacity of tungstate composites. The experimental results were applied to verify the applicability of the Monte Carlo program. PbWO4 and Bi2WO6 were prepared and added into ethylene propylene diene monomer (EPDM) to obtain the composites, which were tested in the {\\gamma}ray shielding. Both the theoretical simulation and experiments were carefully chosen and well designed. The results of the two methods were found to be highly consistent. In addition, the conditions during the numerical simulation were optimized and double-layer {\\gamma}ray shielding systems were studied. It was found that the {\\gamma}-ray shielding performance can be influenced not only by the material thickness ratio but also by the arrangement of the composites.

  12. Cu/WO3-TiO2光催化剂的结构与吸光性能研究%Structure and Photo Absorption Performance of Cu/WO3-TiO2 Photocatalyst

    Institute of Scientific and Technical Information of China (English)

    梅长松; 钟顺和

    2005-01-01

    用溶胶-凝胶法制得复合半导体WO3-TiO2,用浸渍法制得Cu/WO3-TiO2光催化剂.利用XRD、Raman、TPR、IR、TEM、XPS和UV-Vis等技术研究了Cu/WO3-TiO2的物相结构、微粒尺寸和吸光性能.结果表明:含量为10wt%的WO3单分子层分散在TiO2表面,粉体平均粒径15nm.WO3的引入使TiO2吸收限发生明显蓝移,WO3负载量超过单分子层分散(>10wt%),有晶相WO3生成,光吸收性能下降.W-O-Ti键的形成加强了半导体之间的相互作用,有利于光生载流子在半导体间的输送.负载金属Cu促进四面体配位W向八面体配位W转化.

  13. Morphology-controlled Synthesis of CdWO4 Nanocrystals%CdWO4纳米晶形貌可控合成

    Institute of Scientific and Technical Information of China (English)

    杨琳琳; 王永刚; 魏超; 王玉江; 王晓峰; 徐刚; 韩高荣

    2013-01-01

    分别以氯化镉、草酸镉、碳酸镉、柠檬酸镉和钨酸钠为原料,在没有采用模板和表面活性剂的条件下,采用水热法可控制备出了钨酸镉纳米颗粒、纳米棒、纳米束和纳米线.利用X射线衍射(XRD)、透射电镜(TEM)、高分辨透射电子显微镜(HRTEM)和选区电子衍射(SAED)对样品进行了表征.结果表明:[WO42-]/[Cd2+]摩尔比、反应时间及先驱体的类型对产物的形貌和尺寸有着重要的影响.%CdWO4 nanoparticles,nanorods,nanobundles,and nanowires were controllably synthesized via a hydrothermal method without any templates and surfactants using CdCl2,CdC2O4,CdCO3,(C6H5O7)2Cd3,and Na2WO4 as raw materials.The as-prepared powders were characterized by XRD,TEM,HRTEM,and SAED.The results showed that the molar ratio of [WO42-]/[Cd2+],reaction time,and the type of precursors had a crucial effect on the morphology and size of the products.

  14. Novel coupled structures of FeWO4/TiO2 and FeWO4/TiO2/CdS designed for highly efficient visible-light photocatalysis.

    Science.gov (United States)

    Bera, Sandipan; Rawal, Sher Bahadur; Kim, Hark Jin; Lee, Wan In

    2014-06-25

    A quadrilateral disk-shaped FeWO4 nanocrystal (NC) with an average size of ∼35 nm was prepared via hydrothermal reaction. The obtained dark brown FeWO4 NC with a bandgap (Eg) of 1.98 eV was then coupled with TiO2 to form FeWO4/TiO2 composites. The valence band (VB) of FeWO4 (+2.8 eV vs NHE) was more positive than that of TiO2 (+2.7 eV); thus this system could be classified as a Type-B heterojunction. Under visible-light irradiation, 5/95 FeWO4/TiO2 (by wt %) exhibited remarkable photocatalytic activity: the amount of CO2 evolved from gaseous 2-propanol (IP) and the decomposition rate of aqueous salicylic acid (SA) were, respectively, 1.7 and 2.5 times greater than those of typical nitrogen-doped TiO2 (N-TiO2). This unique catalytic property was deduced to arise from the intersemiconductor hole transfer between the VBs of FeWO4 and TiO2. Herein, several experimental evidence were also provided to confirm the hole-transfer mechanism. To further enhance the catalytic efficiency, double-heterojunctioned FeWO4/TiO2/CdS composites were prepared by loading CdS quantum dots (QDs) onto the FeWO4/TiO2 surface. Surprisingly, the catalytic activity for evolving CO2 from IP was 2.6 times greater than that of bare FeWO4/TiO2 and 4.4 times greater than that of N-TiO2, suggesting that both holes and electrons were essential species in decomposing organic compounds.

  15. Bifunctional MoO3-WO3/Ag/MoO3-WO3 Films for Efficient ITO-Free Electrochromic Devices.

    Science.gov (United States)

    Dong, Wenjie; Lv, Ying; Xiao, Lili; Fan, Yi; Zhang, Nan; Liu, Xingyuan

    2016-12-14

    Dielectric-metal-dielectric (DMD) trilayer films, served as both electrochromic (EC) film and transparent conductor (TC), have exhibited great potential application in low-cost, ITO-free electrochromic devices (ECDs). However, recent reports on the DMD-based ECDs revealed that the response time and the optical modulation properties were not very satisfactory. Here, the mixed MoO3-WO3 materials were first introduced as the dielectric layer to construct an EC-TC bifunctional MoO3-WO3/Ag/MoO3-WO3 (MWAMW) film, which demonstrates strong and broad-band optical modulation in the visible light region, fast color-switching time (2.7 s for coloration and 4.1 s for bleaching), along with high coloration efficiency (70 cm(2) C(-1)). The electrical structure and electrochemical reaction kinetics analysis revealed that the improved EC performances are associated with the increased electron intervalence transition together with the fast charge-transfer and ion-diffusion dynamics.

  16. Electrochromic properties and performance of NiOx films and their corresponding all-thin-film flexible devices preparedby reactive DC magnetron sputtering

    Science.gov (United States)

    Dong, Dongmei; Wang, Wenwen; Dong, Guobo; Zhang, Fan; He, Yingchun; Yu, Hang; Liu, Famin; Wang, Mei; Diao, Xungang

    2016-10-01

    Nickel oxide (NiOx) thin films were deposited by direct current magnetron sputtering technique onto flexible substrates with various oxygen (O2) partial pressures. The influence of O2 contents during deposition process on film structure, morphology, composition, optical and electrochromic (EC) characteristics of the films were investigated. The EC response for nonstoichiometric NiOx films shows a strong dependence on grain size variations and surface morphology. Finally, the multiple-layer stacks ITO/NiOx/Ta2O5:H/WO3/ITO were sequentially vacuum deposited over flexible polyethylene terephthalate plates based on the optimization of NiOx single layers. A large optical contrast up to 60% and a good durability are obtained for full device. To perform preliminary research on the mechanical properties within flexible devices, we introduced nontrivial changes to the interfacial properties by replacing the glass with flexible polymers. The effects were studied through static bending and the nano-scratch test.

  17. A study of the effects on the composition of the electrodeposited Ni-TiO{sub 2} composite with the ultrasonic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myongjin; Kim, Joung Soo; Kim, Dong Jin; Kimm, Hong Pyo; Hwang, Seong Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-04-15

    In the present study, Ni-TiO{sub 2} composite coatings were electrodeposited in a sulfamate bath containing TiO{sub 2} particles. The influence of the ultrasonic treatment on the co-deposition of TiO{sub 2} particles in the coating and the hardness of the electrodeposited Ni-TiO{sub 2} composite has been investigated. Three different ultrasonic treatments (pretreatment before the electrodeposition (pre-UT), pretreatment + applied during the electrodeposition (UT), and the electrodeposition without the ultrasonic treatment (w/o UT)) were performed. The Ni-TiO{sub 2} composite coatings are characterized using scanning electron microscopy (SEM), image analyzer, and hardness tester. Comparison of results indicates that the volume fraction is more important factor than the agglomerated particle size in terms of the strength improvement, and the strength of the electrodeposited Ni-TiO{sub 2} composite coatings is enhanced with pre-UT condition.

  18. Enhanced structural and optical properties of the polyaniline-calcium tungstate (PANI-CaWO4 nanocomposite for electronics applications

    Science.gov (United States)

    Sabu, N. Aloysius; Francis, Xavier; Anjaly, Jose; Sankararaman, S.; Varghese, Thomas

    2017-06-01

    In this article, we report the synthesis and characterization of polyaniline-calcium tungstate nanocomposite, a novel material for potential applications. The PANI-CaWO4 nanocomposite was prepared by in situ oxidative polymerization of aniline in the presence of CaWO4 nanoparticles dispersed in ethanol. Investigations using X-ray diffraction, Fourier-transformed infrared spectroscopy, UV-visible, photoluminescence and Raman spectroscopy confirmed the formation of the nanocomposite of PANI with CaWO4 nanoparticles. Scanning electron microscopy revealed almost uniform distribution of CaWO4 nanoparticles in the polyaniline matrix. These studies also confirmed electronic structure modification as a result of incorporating CaWO4 nanoparticles in PANI. Composite formation resulted in large decrease in the optical band gap and enhanced photoluminescence. The augmented structural, optical and photoluminescence properties of the PANI-CaWO4 nanocomposite can be used to explore potential applications in micro- and optoelectronics. This is the first report presenting synthesis and characterization of the PANI-CaWO4 nanocomposite.

  19. Sensing performance of palladium-functionalized WO{sub 3} nanowires by a drop-casting method

    Energy Technology Data Exchange (ETDEWEB)

    Chávez, F., E-mail: f_perez_s@hotmail.com [Department of Physical-Chemical Materials, ICUAP-BUAP, 72000, Puebla (Mexico); Pérez-Sánchez, G.F. [Department of Physical-Chemical Materials, ICUAP-BUAP, 72000, Puebla (Mexico); Goiz, O. [Department of Electrical Engineering, CINVESTAV-IPN, 07360, México, D.F (Mexico); Zaca-Morán, P. [Department of Physical-Chemical Materials, ICUAP-BUAP, 72000, Puebla (Mexico); Peña-Sierra, R.; Morales-Acevedo, A. [Department of Electrical Engineering, CINVESTAV-IPN, 07360, México, D.F (Mexico); Felipe, C. [Department of Biosciences and Engineering, CIIEMAD-IPN, 07340, México, D.F (Mexico); Soledad-Priego, M. [Faculty of Electronics Sciences, FCE, 72000, Puebla (Mexico)

    2013-06-15

    In this work, we show a simple way to functionalize tungsten oxide nanowires (WO{sub 3}-NWs) using a saturated palladium chloride (PdCl{sub 2}) solution deposited by a drop-casting method. WO{sub 3}-NWs were synthesized by close-spaced chemical vapor deposition (CSVT). The morphological and structural characterizations showed that the diameters of WO{sub 3}-NWs are in the range from 50 to 200 nm with lengths above 10 μm, and correspond to the orthorhombic phase of WO{sub 3}, respectively. The sensor was fabricated using the WO{sub 3}-NWs and tested with hydrogen and volatile organic compounds (VCO's). A comparative study was done on the sensing performance, before and after the Palladium functionalization of the WO{sub 3}-NWs, considering a wide range of gas concentrations and moderate operating temperatures (100–400 °C). The results show that this simple functionalization process significantly increases the sensor sensitivity and reduces the time constants. In addition, it has been shown that at 300 °C the decorated sensor becomes more selective to hydrogen and xylene for all concentrations considered in this research. Finally, the mechanisms involved in improving the gas sensing properties of WO{sub 3}-NWs functionalized with Palladium are discussed.

  20. Hierarchical Bi2WO6 architectures decorated with Pd nanoparticles for enhanced visible-light-driven photocatalytic activities

    Science.gov (United States)

    Zhang, Jinniu; Chen, Tianhua; Lu, Hongbing; Yang, Zhibo; Yin, Feng; Gao, Jianzhi; Liu, Qianru; Tu, Yafang

    2017-05-01

    A new kind of hierarchical Pd-Bi2WO6 architecture decorated with different molar ratios of Pd to Bi, has been fabricated by a hydrothermal process, followed by a chemical deposition method. The photocatalytic activities of the pure Bi2WO6 and Pd-Bi2WO6 nanocatalyst were examined in the degradation of Rhodamine B (RhB) dyes and phenol under visible light. The photocatalytic results showed that the Pd-Bi2WO6 nanocomposites possessed observably enhanced photocatalytic activities. Particularly, the 2.0% Pd loaded Bi2WO6 had the highest photocatalytic activity, exhibiting a nearly complete degradation of 30 mg/L RhB and 10 mg/L phenol within only 50 and 60 min, respectively. In addition, the trapping experiment results indicated that the photo-generated holes (h+) and rad O2- played a crucial role in the degradation of RhB. According to the experimental results, the photocatalytic degradation mechanism of Pd-Bi2WO6 was also proposed. The enhanced photocatalytic activities were ascribed to the combined effects of the highly efficient separation of electrons and holes, improved visible light utilization and increased BET specific surface areas of the Pd-Bi2WO6 nanocomposites.

  1. ZnWO_4 nanocrystals/reduced graphene oxide hybrids:Synthesis and their application for Li ion batteries

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao; LI BoLong; LIU DaPeng; XIONG HuanMing

    2014-01-01

    ZnWO4,as an environment-friendly and economic material,has the potential for Li ion batteries(LIB)application.In this paper,a facile method has been developed to synthesize ZnWO4supported on the reduced graphene oxide(RGO)to improve its LIB performance.The cuboid-like ZnWO4nanocrystals are prepared by directly adding Na2WO4 powders into the graphene oxide/Zn aqueous solution followed by a hydrothermal treatment.The high-resolution TEM,XRD and XPS characterizations were employed to demonstrate structural information of the as-prepared ZnWO4/RGO hybrids carefully.Besides,we also discussed the LIB properties of the hybrids based on the detailed galvanostatic charge-discharge cycling tests.As a result,the specific capacity of the as-prepared ZnWO4/RGO hybrids reached more than 477.3 mA h g 1after 40 cycles at a current density of 100 mA g 1(only less than 159 mA g 1for bare ZnWO4).During the whole cyclic process,the coulombic efficiency steadily kept the values higher than 90%.

  2. Modification of TiO{sub 2} nanotubes by WO{sub 3} species for improving their photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hui, E-mail: sunhuichn@hotmail.com; Dong, Bohua, E-mail: dongbohua@ouc.edu.cn; Su, Ge, E-mail: gesu@ouc.edu.cn; Gao, Rongjie, E-mail: dmh206@ouc.edu.cn; Liu, Wei, E-mail: weiliu@ouc.edu.cn; Song, Liang, E-mail: songliang@qibebt.ac.cn; Cao, Lixin, E-mail: caolixin@mail.ouc.edu.cn

    2015-07-15

    Highlights: • WO{sub 3}/titania nanotubes are synthesized at low temperature (383 K) by a novel approach. • WO{sub 3}/titania nanotubes present enhanced photocatalytic activity. • The substitution of Ti{sup 4+} by W{sup 6+} does not occur in nanocomposites at 383 K. • Diffuse reflectance spectra of WO{sub 3}/TNTs exhibit a red shift due to WO{sub 3} connection. • The optimal degradation rate of MO could reach 95% within 2 h irradiation. - Abstract: WO{sub 3}/TiO{sub 2} nanotubular composite was synthesized at low temperature (383 K) by a novel approach. WO{sub 3} nanoparticles were loaded on anatase TiO{sub 2} nanotubes through the reaction between (NH{sub 4}){sub 6}W{sub 7}O{sub 24}·6H{sub 2}O and aqueous solution of HCl. The obtained products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV–vis diffuse reflectance spectroscopy (UV-DRS). Degradation of methyl orange was employed to investigate the photocatalytic activity of the products. Results show that, among the samples with different concentrations of WO{sub 3}, W{sub 10}T with the atomic ratio W/Ti of 10% presents optimal degradation rate. This degradation rate is about 95% within 2 h under UV light irradiation, which is much higher than that of pure TiO{sub 2} nanotubes.

  3. Reduced graphene oxide wrapped Bi2WO6 hybrid with ultrafast charge separation and improved photoelectrocatalytic performance

    Science.gov (United States)

    Wang, Huan; Liang, Yinghua; Liu, Li; Hu, Jinshan; Cui, Wenquan

    2017-01-01

    A reduced graphene oxide (rGO) wrapped Bi2WO6 (Bi2WO6@rGO) hybrid as photoelectrode for enhanced photoelectrocatalytic (PEC) degradation of organic pollutants is reported, which exhibited excellent charge separation and photoconversion efficiency. The core@shell structured Bi2WO6@rGO photoelectrode yielded a pronounced 1.56-fold and 23.8-fold photocurrent density at 1.0 V vs. saturated calomel electrode (SCE), than that of loading structured Bi2WO6-rGO and pure Bi2WO6. The Bi2WO6@rGO hybrid exhibited enhanced photoelectrocatalytic efficiency for degradation of Rhodamine B (RhB), which was 43.0% and 65.6% higher than that of photocatalytic (PC) and electrocatalytic (EC) processes, respectively. The enhancement in PEC degradation of RhB benefited from: (1) a strong interaction and a wide range of conjugation were formed in the core@shell system; (2) a 0.26 V of flat band potential was negatively shifted in case of Bi2WO6@rGO composite; (3) the photogenerated electrons and holes could be spatially separated by external electric potentials.

  4. Improved WO3 photocatalytic efficiency using ZrO2 and Ru for the degradation of carbofuran and ampicillin.

    Science.gov (United States)

    Gar Alalm, Mohamed; Ookawara, Shinichi; Fukushi, Daisuke; Sato, Akira; Tawfik, Ahmed

    2016-01-25

    The photocatalytic degradation of carbofuran (pesticide) and ampicillin (pharmaceutical) using synthesized WO3/ZrO2 nanoparticles under simulated solar light was investigated. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectra analyses were used to characterize the prepared catalysts. The optimum ratio of WO3 to ZrO2 was determined to be 1:1 for the degradation of both contaminants. The degradation of carbofuran and ampicillin by WO3/ZrO2 after 240 min of irradiation was 100% and 96%, respectively. Ruthenium (Ru) was employed as an additive to WO3/ZrO2 to enhance the photocatalytic degradation rate. Ru/WO3/ZrO2 exhibited faster degradation rates than WO3/ZrO2. Furthermore, 100% and 97% degradation of carbofuran and ampicillin, respectively, was achieved using Ru/WO3/ZrO2 after 180 min of irradiation. The durability of the catalyst was investigated by reusing the same suspended catalyst, which achieved 92% of its initial efficiency. The photocatalytic degradation of ampicillin and carbofuran followed pseudo-first order kinetics according to the Langmuir-Hinshelwood model.

  5. Nanocrystalline Pd:NiFe2O4 thin films: A selective ethanol gas sensor

    Science.gov (United States)

    Rao, Pratibha; Godbole, R. V.; Bhagwat, Sunita

    2016-10-01

    In this work, Pd:NiFe2O4 thin films were investigated for the detection of reducing gases. These films were fabricated using spray pyrolysis technique and characterized using X-ray diffraction (XRD) to confirm the crystal structure. The surface morphology was studied using scanning electron microscopy (SEM). Magnetization measurements were carried out using SQUID VSM, which shows ferrimagnetic behavior of the samples. These thin film sensors were tested against methanol, ethanol, hydrogen sulfide and liquid petroleum gas, where they were found to be more selective to ethanol. The fabricated thin film sensors exhibited linear response signal for all the gases with concentrations up to 5 w/o Pd. Reduction in optimum operating temperature and enhancement in response was also observed. Pd:NiFe2O4 thin films exhibited faster response and recovery characteristic. These sensors have potential for industrial applications because of their long-term stability, low power requirement and low production cost.

  6. Diversity of minor elements in olivines from mantle xenoliths (Wołek Hill, SW Poland) - PIXE measurements

    Science.gov (United States)

    Nowak, Monika; Munnik, Frans; Michalak, Przemysław P.; Renno, Axel

    2016-04-01

    Wołek Hill is one of the best examined exposures of Cenozoic volcanic rocks from SW Poland (Nowak, 2012). This is related with two facts: a great amount of mantle xenoliths were collected from that outcrop and this is one of two occurrences in Poland were modal metasomatism (related with amphibole crystals presence) was recognized. Wołek Hill is a relatively small exposure and belongs to the Złotoryja Volcanic Field, which is one of the volcanic concentrations in the Polish part of the Central European Volcanic Province (Ladenberger et al. 2006). Based on previous observations olivine crystals from the inside part of xenoliths occasionally display internal inhomogeneity visible on a BSE image. Such inhomogeneity has been related to olivine "sub-grains" with slightly shifted crystal axis. Those "sub-grains" are visible in optical microscope as transitional lamellae (Nowak, Stawikowski 2009). Besides the mentioned visible inhomogeneity olivine crystals also show diversity in Ca content inside single crystals (sometimes even more than 200 ppm). EPMA standard measurements (15 kV, 20 nA, time: 40 seconds) were limited to beam size and detection limits of the microprobe (most of the obtained results oscillate close to the detection limits - or even below it). Special conditions EPMA analyses (15 kV, 100nA, time: 100s) confirmed the differences in Ca content in the studied olivines, but did not provide any idea on how to interpret the results (Nowak, 2012). In this short summary we present preliminary data of olivine minor element composition (Ca, Zn, Cr, Ti, Co, K and also Mn, Ni, Fe) obtained with Particle Induced X-ray Emission(PIXE) measurements performed at the HZDR in Dresden using a 3 MeV proton beam, 1-1.5 nA current and an acquisition time of 3 hrs for each scan. The size of individual scans varied from ca. 30 μm up to 60-65 μm, with 8 x 8 measurement points - min. 4 μm in diameter. The measurements have been analysed with the GeoPIXE software (Ryan, 2001

  7. Structural phototransformation of WO{sub 3} thin films detected by photoacoustic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Argelia Perez, E-mail: ekargy@hotmail.com [Universidad Nacional Autonoma de Mexico, Laboratorio de Fotofisica y Peliculas Delgadas-CCADET, Ciudad Universitaria, Coyoacan, A.P. 70-186, C.P. 04510, Mexico, D.F. (Mexico); Montes de Oca, C. Oliva; Castaneda-Guzman, R.; Garcia, A. Esparza [Universidad Nacional Autonoma de Mexico, Laboratorio de Fotofisica y Peliculas Delgadas-CCADET, Ciudad Universitaria, Coyoacan, A.P. 70-186, C.P. 04510, Mexico, D.F. (Mexico)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The phototransformation of WO{sub 3} thin films were studied by photoacoustic technique. Black-Right-Pointing-Pointer The phase transition in WO{sub 3} thin films was induced by laser irradiation fluence. Black-Right-Pointing-Pointer The onset and end of the phototransformation in the thin films was identified. Black-Right-Pointing-Pointer The ablation threshold for each sample was identified. - Abstract: The photoacoustic technique (PA) was used to detect the phase transformation from amorphous to crystalline state of tungsten oxide (WO{sub 3}) thin films induced by UV pulsed laser radiation at low energy (<1.5 mJ). The evolution of photoacoustic signal was studied by a correlation analysis, comparing successive signals at fluences ranging from 0 to 20 mJ/cm{sup 2}. In this interval, it was possible to observe structural changes and the ablation threshold in films due to incident laser fluence effect. Thin films of WO{sub 3} were deposited by DC reactive magnetron sputtering over glass substrates at different deposition times. The results obtained by correlation analysis were compared with Raman spectroscopy data.

  8. Hydrothermal synthesis of hierarchical WO{sub 3} nanostructures for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rashad, M.M. [Central Metallurgical Research and Development Institute (CMRDI), Helwan, P.O. Box 87, Cairo (Egypt); Shalan, A.E. [Central Metallurgical Research and Development Institute (CMRDI), Helwan, P.O. Box 87, Cairo (Egypt); Friedrich-Alexander-University of Erlangen-Nuremberg, Institute of Materials for Electronics and Energy Technology (i-MEET), Erlangen (Germany)

    2014-08-15

    Hierarchical architectures consisting of one-dimensional (1D) nanostructures are of great interest for potential use in energy and environmental applications in recent years. In this work, hierarchical tungsten oxide (WO{sub 3}) has been synthesized via a facile hydrothermal route from ammonium metatungstate hydrate and implemented as photoelectrode for dye-sensitized solar cells. The urchin-like WO{sub 3} micro-patterns are constructed by self-organized nanoscale length 1D building blocks, which are single crystalline in nature, grown along (001) direction and confirm an orthorhombic crystal phase. The obtained powders were investigated by XRD, SEM, TEM and UV-Vis Spectroscopy. The photovoltaic performance of dye-sensitized solar cells based on WO{sub 3} photoanodes was investigated. With increasing the calcination temperature of the prepared nanopowders, the light-electricity conversion efficiency (η) was increased. The results were attributed to increase the crystallinity of the particles and ease of electron movement. The DSSC based on hierarchical WO{sub 3} showed a short-circuit current, an open-circuit voltage, a fill factor, and a conversion efficiency of 4.241 mA/cm{sup 2}, 0.656 V, 66.74, and 1.85 %, respectively. (orig.)

  9. WoSIS: providing standardised soil profile data for the world

    Science.gov (United States)

    Batjes, Niels H.; Ribeiro, Eloi; van Oostrum, Ad; Leenaars, Johan; Hengl, Tom; Mendes de Jesus, Jorge

    2017-01-01

    The aim of the World Soil Information Service (WoSIS) is to serve quality-assessed, georeferenced soil data (point, polygon, and grid) to the international community upon their standardisation and harmonisation. So far, the focus has been on developing procedures for legacy point data with special attention to the selection of soil analytical and physical properties considered in the GlobalSoilMap specifications (e.g. organic carbon, soil pH, soil texture (sand, silt, and clay), coarse fragments ( definitions, soil property values, and soil analytical method descriptions. At the time of writing, the full WoSIS database contained some 118 400 unique shared soil profiles, of which some 96 000 are georeferenced within defined limits. In total, this corresponds with over 31 million soil records, of which some 20 % have so far been quality-assessed and standardised using the sequential procedure discussed in this paper. The number of measured data for each property varies between profiles and with depth, generally depending on the purpose of the initial studies. Overall, the data lineage strongly determined which data could be standardised with acceptable confidence in accord with WoSIS procedures, corresponding to over 4 million records for 94 441 profiles. The publicly available data - WoSIS snapshot of July 2016 - are persistently accessible from ISRIC WDC-Soils through doi:10.17027/isric-wdcsoils.20160003.

  10. Novel rib structures in Yb-doped KY(WO4)2 for laser applications

    NARCIS (Netherlands)

    Gardillou, F.; Borca, C.N.; Romanyuk, Y.E.; Hibert, C.; Salathé, R.P.; Pollnau, Markus

    2006-01-01

    We report for the first time, on the fabrication of flexible refractive-index-contrast rib waveguides based on Yb-doped $KY(WO_4)_2$ epilayers. These results pave the way for integrated optical circuits in this promising material.

  11. Phase modification and surface plasmon resonance of Au/WO{sub 3} system

    Energy Technology Data Exchange (ETDEWEB)

    Bose, R. Jolly; Kavitha, V.S. [Department of Optoelectronics, University of Kerala, Kariyavattom, Thiruvananthapuram 691574, Kerala (India); Sudarsanakumar, C. [School of Pure and Applied Physics, Mahatma Gandhi University, Priyadarshini Hills, Kottayam 686560, Kerala (India); Pillai, V.P. Mahadevan, E-mail: vpmpillai9@gmail.com [Department of Optoelectronics, University of Kerala, Kariyavattom, Thiruvananthapuram 691574, Kerala (India)

    2016-08-30

    Highlights: • We have investigated the role of gold as catalyst and nucleation centers, for the crystallization and phase modification of tungsten oxide, in Au/WO{sub 3} matrix. • The phase change from triclinic WO{sub 3} to monoclinic W{sub 18}O{sub 49} is found to enhance with gold incorporation. • The surface plasmon resonance is observed in gold/tungsten oxide system with the appearance of an absorption band near the wavelength 604 nm. - Abstract: We report the action of gold as catalyst for the modification of phase from triclinic WO{sub 3} to monoclinic W{sub 18}O{sub 49} and nucleation centre for the formation of W{sub 18}O{sub 49} phase, in gold incorporated tungsten oxide films prepared by RF magnetron sputtering technique. A new band is observed near 925 cm{sup −1} in the Raman spectra of gold incorporated tungsten oxide films which is not observed in the pure tungsten oxide film. The intensity of this band enhances with gold content. A localized surface plasmon resonance (LSPR) band is observed near the wavelength 604 nm in gold incorporated tungsten oxide films. The integrated intensities of LSPR band and Raman band (∼925 cm{sup −1}) can be used for sensing the quantity of gold in the Au/WO{sub 3} matrix.

  12. Fabrication and capacitive characteristics of conjugated polymer composite p-polyaniline/n-WO{sub 3} heterojunction

    Energy Technology Data Exchange (ETDEWEB)

    Amaechi, C.I.; Asogwa, P.U.; Ekwealor, A.B.C. [University of Nigeria, Department of Physics and Astronomy, Nsukka, Enugu State (Nigeria); Osuji, R.U.; Ezema, F.I. [University of Nigeria, Department of Physics and Astronomy, Nsukka, Enugu State (Nigeria); iThemba LABS-National Research Foundation, Nanosciences African Network (NANOAFNET), Somerset West, Western Cape Province (South Africa); University of South Africa (UNISA), UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, Pretoria (South Africa); Maaza, M. [iThemba LABS-National Research Foundation, Nanosciences African Network (NANOAFNET), Somerset West, Western Cape Province (South Africa); University of South Africa (UNISA), UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, Pretoria (South Africa)

    2014-11-15

    A nanocrystalline and porous p-polyaniline/n-WO{sub 3} dissimilar heterojunction at ambient temperature is reported. The high-quality and well-reproducible conjugated polymer composite films have been fabricated by oxidative polymerization of anilinium ion on predeposited WO{sub 3} thin film by chemical bath deposition followed by thermal annealing at 573 K for 1 h. Atomic force microscopy (AFM) analyses reveal a homogenous but irregular cluster of faceted spherically shaped grains with pores. The scanning electron microscopy confirms the porous network of grains, which is in good agreement with the AFM result. The optical absorption analysis of polyaniline/WO{sub 3} hybrid films showed that direct optical transition exist in the photon energy range 3.50-4.00 eV with bandgap of 3.70 eV. The refractive index developed peak at 445 nm in the dispersion region while the high-frequency dielectric constant, ε {sub ∞}, and the carrier concentration to effective mass ratio, N/m{sup *}, was found to be 1.58 and 1.10 x 10{sup 39} cm{sup -3}, respectively. The temperature dependence of electrical resistivity of the deposited films follows the semiconductor behavior while the C-V characteristics (Mott-Schottky plots) show that the flat band potential was -791 and 830 meV/SCE for WO{sub 3} and polyaniline. (orig.)

  13. Characterization of CaWO{sub 4} scintillator at room and liquid nitrogen temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Moszynski, M. [Soltan Institute for Nuclear Studies, PL 05-400 Otwock-Swierk (Poland)]. E-mail: marek@ipj.gov.pl; Balcerzyk, M. [Soltan Institute for Nuclear Studies, PL 05-400 Otwock-Swierk (Poland); Czarnacki, W. [Soltan Institute for Nuclear Studies, PL 05-400 Otwock-Swierk (Poland); Nassalski, A. [Soltan Institute for Nuclear Studies, PL 05-400 Otwock-Swierk (Poland); Szczesniak, T. [Soltan Institute for Nuclear Studies, PL 05-400 Otwock-Swierk (Poland); Kraus, H. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Mikhailik, V.B. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Solskii, I.M. [Institute of Materials SRC ' Carat' , Lviv 790031 (Ukraine)

    2005-11-21

    The properties of CaWO{sub 4} (CaWO) crystals in {gamma}-spectrometry were studied at room and liquid nitrogen(LN{sub 2}) temperatures. Two small samples of 10x10x4 mm{sup 3} and 10x10x8 mm{sup 3} size were tested, coupled to a Photonis XP3212 photomultiplier at room temperature and a large area avalanche photodiode at LN{sub 2} temperature. Light pulse shape and light output at room and LN{sub 2} temperatures were measured. Energy resolution and non-proportionality of the CaWO response versus {gamma}-ray energy were studied and compared with those of small BGO and CdWO{sub 4} crystals to discuss further the origin of the intrinsic resolution of undoped scintillating crystals. A high light output of 4800{+-}200 phe/MeV and a good energy resolution of 6.6{+-}0.2% for 662 keV {gamma}-rays from a {sup 137}Cs source were measured for the small samples coupled to the XP3212 photomultiplier.

  14. Enhanced photocatalytic activity in anodized WO3-loaded TiO2 nanotubes

    Science.gov (United States)

    Nazari, M.; Golestani-Fard, F.; Bayati, R.; Eftekhari-Yekta, B.

    2015-04-01

    In this work, TiO2 and WO3-grafted TiO2 nanotubes were grown via anodizing of titanium substrates in tungstate containing electrolytes. The samples were characterized in detail by XRD, XPS, SEM, EDX, and UV-Vis spectrophotometry techniques. Besides, photocatalytic characteristics were evaluated through measuring the degradation rate of 4-chlorophenol to establish a correlation between structure and photochemical properties. We were able to control morphology and growth mode of nanotubes from a tubular to a worm-like structure by changing the electrolyte composition. The samples possessed an anatase-rutile matrix where the anatase/rutile ratio was found to increase with the concentration of tungstate in the electrolyte. We attributed this observation to change in electrical conductivity of the electrolyte and the heat generated on the substrates. It was unambiguously revealed that a composite of WO3 and TiO2 forms and, in parallel, tungsten is doped into the crystalline lattice of TiO2. The maximum photocatalytic reaction rate constant for TiO2 and WO3-TiO2 samples was determined to be 0.0131 and 0.0174 min-1 respectively. The grafting TiO2 nanotubes with WO3 enhances the photocatalytic activity mainly due to the hindrance of charge carrier recombination and the formation of a more acidic surface. We established a correlation between structure, stoichiometry, and photocatalytic characteristics of nanotubes.

  15. On the nature of the WO3 star DR1 in IC 1613

    CERN Document Server

    Tramper, F; Hartoog, O E; Sana, H; de Koter, A; Vink, J S; Ellerbroek, L E; Langer, N; Garcia, M; Kaper, L; de Mink, S E

    2013-01-01

    We present the results of a quantitative spectroscopic analysis of the oxygen-sequence Wolf- Rayet star DR1 in the low-metallicity galaxy IC 1613. Our models suggest that the strong oxygen emission lines are the result of the high temperature of this WO3 star and do not necessarily reflect a more advanced evolutionary stage than WC stars.

  16. Alkali-Phosphate Glasses Containing WO3 and Nb2O5

    Directory of Open Access Journals (Sweden)

    L. Bih

    2013-01-01

    Full Text Available New phosphate glasses in the quaternary system (50-x A2O-x WO3-10 Nb2O5-40 P2O5, with x = 0; 30 and A = Li or Na were prepared by the melt quenching method. The effect on the crystallization behaviour of the glass due to the introduction of WO3 into the glass composition and, consequently, the diminishing of the molar amount of the alkaline oxide and the decreasing of the molar ratio between network modifiers and network formers (M/F was studied. The prepared glasses were heat-treated in air, at 550°C, 600°C, and 650°C for 4 hours. The structure, of the obtained samples, was studied by differential thermal analysis (DTA, X-ray powder diffraction (XRD, and Raman spectroscopy and the morphology by scanning electron microscopy (SEM. It was found that the replacement of Li2O or Na2O by WO3 reduces the number of the crystallised phases. In the lithium-niobiophosphate glasses, the presence of WO3 promotes the formation of NbOPO4 instead of the LiNbO3 phase and reduces the formation of ortho- and pyro-phosphate phases. The thermal treatments affect the arrangements of the network structure of the AW40-glasses.

  17. Electrochemical Performance of Morphologically Different Bi2WO6 Nanostructures Synthesized via a Hydrothermal Route

    Science.gov (United States)

    Wang, Fei; Yang, Hua; Zhang, Haimin; Su, Junyan; Wang, Xiangxian

    2017-01-01

    Morphologically different Bi2WO6 nanostructures have been synthesized via a hydrothermal route, where the morphology was tailored by varying the pH value of the precursor solution. The samples prepared at pH 1, 7, and 11 consisted of flower-like hierarchical structures with average diameter of 7 μm, irregular flake-like structures with average thickness of 90 nm, and uniform spherical structures with average size of 85 nm, respectively. The electrochemical performance of the as-prepared Bi2WO6 samples was investigated by cyclic voltammetry, galvanostatic charge-discharge measurements, and electrochemical impedance spectroscopy. In 1 M KOH electrolyte at current density of 0.5 mA cm-2, the specific capacitance of the Bi2WO6 with flower-like hierarchical, flake-like, and spherical structure was measured to be 255 F g-1, 214 F g-1, and 412 F g-1, respectively. After 850 charge-discharge cycles at current density of 3 mA cm-2, the capacitance of the three samples remained at 87%, 78%, and 95% of the initial value, respectively. Among the three types of Bi2WO6 morphology, the spherical structure delivered the best electrochemical performance.

  18. Hydrothermal Synthesis and Ammonia Sensing Properties of WO3/Fe2O3 Nanorod Composites

    Science.gov (United States)

    Dien, Nguyen Dac; Phuoc, Luong Huu; Hien, Vu Xuan; Vuong, Dang Duc; Chien, Nguyen Duc

    2017-01-01

    WO3 nanorods (NRs) and α-Fe2O3 NRs were fabricated by hydrothermal treatment. Composites of these materials were created by mixing with ratios of 1:2, 1:1 and 2:1 in weight. Morphology, structure and composition characteristics of the WO3/Fe2O3 NRs composites were characterized by scanning electron microscopy, x-ray diffraction and energy dispersive x-ray spectroscopy analyses. The results of sensing measurements indicated that the sensor based on WO3:Fe2O3 with the ratio of 2:1 exhibited fairly good sensitivity toward NH3 at 300°C and the sensor based on WO3:Fe2O3 with the ratio of 1:1 can be used as a NH3 sensor with an operating temperature of 350°C. Selectivity and response-recovery times are suitable for practical applications. Finally, the mechanism for the improvement in the gas-sensing property was discussed.

  19. Electrical conductivity and defect chemistry of PbMoO4 and PbWO4

    NARCIS (Netherlands)

    Groenink, J.A.; Binsma, H.

    1979-01-01

    The ionic and electronic conductivities of Czochralski-grown single crystals of PbMoO4 and PbWO4 are reported and discussed. Nominally pure crystals, as well as crystals with various aliovalent dopants, were used. From the electrical measurements it is concluded that oxygen vacancies are responsible

  20. Ultrasmall Biocompatible WO3- x Nanodots for Multi-Modality Imaging and Combined Therapy of Cancers.

    Science.gov (United States)

    Wen, Ling; Chen, Ling; Zheng, Shimin; Zeng, Jianfeng; Duan, Guangxin; Wang, Yong; Wang, Guanglin; Chai, Zhifang; Li, Zhen; Gao, Mingyuan

    2016-07-01

    Ultrasmall biocompatible WO3 - x nanodots with an outstanding X-ray radiation sensitization effect are prepared, and demonstrated to be applicable for multi-modality tumor imaging through computed tomography and photoacoustic imaging (PAI), and effective cancer treatment combining both photothermal therapy and radiation therapy.

  1. Characterization of MeWO 4 (Me = Ba, Sr and Ca) nanocrystallines prepared by sonochemical method

    Science.gov (United States)

    Thongtem, Titipun; Phuruangrat, Anukorn; Thongtem, Somchai

    2008-09-01

    Metal tungstates (MeWO 4, Me = Ba, Sr and Ca) were successfully prepared using the corresponding Me(NO 3) 2·2H 2O and Na 2WO 4·2H 2O in ethylene glycol by the 5 h sonochemical process. The tungstate phases with scheelite structure were detected with X-ray diffraction (XRD) and selected area electron diffraction (SAED). Their calculated lattice parameters are in accord with those of the JCPDS cards. Transmission electron microscopy (TEM) revealed the presence of nanoparticles composing the products. Their average sizes are 42.0 ± 10.4, 18.5 ± 5.1 and 13.1 ± 3.3 nm for Me = Ba, Sr and Ca, respectively. Interplanar spaces of the crystals were also characterized with high-resolution TEM (HRTEM). Their crystallographic planes are aligned in systematic array. Six different vibration wavenumbers were detected using Raman spectrometer and are specified as ν1(A g), ν3(B g), ν3(E g), ν4(B g), ν2(A g) and free rotation. Fourier transform infrared (FTIR) spectra provided the evidence of scheelite structure with W-O anti-symmetric stretching vibration of [WO 4] 2- tetrahedrons at 786-883 cm -1. Photoluminescence emission of the products was detected over the range of 384-416 nm.

  2. Raman signatures of charge ordering in K0.3WO3

    NARCIS (Netherlands)

    Sagar, D. M.; Fausti, D.; van Smaalen, S.; van Loosdrecht, P. H. M.

    2010-01-01

    We present polarization- and temperature-dependent Raman spectroscopic study of hexagonal tungsten bronze, K0.3WO3. The observed asymmetry in phonon line shapes indicate the presence of strong lattice anharmonicity arising due to the nonstoichiometry of the material. We observed a broad multipeak Ra

  3. Synthesis of wo3 nanogranular thin films by hot-wire CVD

    NARCIS (Netherlands)

    Houweling, Z.S.; Geus, J.W.; Schropp, R.E.I.

    2010-01-01

    By resistively heating tungsten filaments in a constant air flow under a reduced pressure, nanogranular amorphous WO3 thin films are deposited on glassy carbon substrates. The substrate surface temperature is monitored by a thermocouple. For deposition times of 15 min and longer, the films show crys

  4. BIBLIOMETRIC ANALYSIS OF PUBLICATIONS ON WINE TOURISM IN THE DATABASES Scopus and WoS

    Directory of Open Access Journals (Sweden)

    Durán Sánchez, Amador

    2017-01-01

    on the results of the comparative study, we conclude that WoS and Scopus databases differ in scope, data volume and coverage policies with a high degree of unique sources and articles, resulting both of them complementary and not mutually exclusive. Scopus covers the area of wine tourism better, by including a greater number of journals, papers and signatures."

  5. Thermally induced evolution of sol–gel grown WO3 films on ITO/glass substrates

    NARCIS (Netherlands)

    Caruso, T.; Castriota, M.; Policicchio, A.; Fasanella, A.; Santo, M.P. De; Ciuchi, F.; Desiderio, G.; Rosa, S. La; Rudolf, P.; Agostino, R.G.; Cazzanelli, E.

    2014-01-01

    The electronic, morphological and structural properties of WO3 thin films, synthesized via a sol-gel route and deposited on ITO/glass substrates by spin-coating, were analyzed as a function of annealing temperature (100-700 degrees C range) by Scanning Electron Microscopy, Atomic Force Microscopy, m

  6. Growth of NaBi(WO4)2 Dendrite and Mechanism

    Institute of Scientific and Technical Information of China (English)

    HONG Yong; AI Fei; PAN Xiu-Hong; JIN Wei-Qing; ZHONG Wei-Zhuo; SHINICHI Yoda

    2006-01-01

    @@ The solid-liquid interface motion of NaBi(WO4)2 (NBWO) melt crystal growth is observed in an in situ system,in which the whole processes of interface transition from flat interface and cellular to dendrite are visualized.

  7. A MEMS-based Benzene Gas Sensor with a Self-heating WO3 Sensing Layer

    Directory of Open Access Journals (Sweden)

    Lung-Ming Fu

    2009-04-01

    Full Text Available In the study, a MEMS-based benzene gas sensor is presented, consisting of a quartz substrate, a thin-film WO3 sensing layer, an integrated Pt micro-heater, and Pt interdigitated electrodes (IDEs. When benzene is present in the atmosphere, oxidation occurs on the heated WO3 sensing layer. This causes a change in the electrical conductivity of the WO3 film, and hence changes the resistance between the IDEs. The benzene concentration is then computed from the change in the measured resistance. A specific orientation of the WO3 layer is obtained by optimizing the sputtering process parameters. It is found that the sensitivity of the gas sensor is optimized at a working temperature of 300 °C. At the optimal working temperature, the experimental results show that the sensor has a high degree of sensitivity (1.0 KΩ ppm-1, a low detection limit (0.2 ppm and a rapid response time (35 s.

  8. Microstructural and Mechanical Studies of PVA Doped with ZnO and WO3 Composites Films

    Directory of Open Access Journals (Sweden)

    N. B. Rithin Kumar

    2014-01-01

    Full Text Available Polymer composites of ZnO and WO3 nanoparticles doped polyvinyl alcohol (PVA matrix have been prepared using solvent casting method. The microstructural properties of prepared films were studied using FTIR, XRD, SEM, and EDAX techniques. In the doped PVA, many irregular shifts in the FTIR spectra have been observed and these shifts in bands can be understood on the basis of intra/intermolecular hydrogen bonding with the adjacent OH group of PVA. The chemical composition, phase homogeneity, and morphology of the polymer composites of the polymer film were studied using EDAX and SEM. These data indicate that the distribution of nanosized ZnO and WO3 dopants is uniform and confirm the presence of ZnO and WO3 in the film. The crystal structure and crystallinity of polymer composites were studied by XRD. It was found that the change in structural repositioning and crystallinity of the composites takes place due to the interaction of dopants and also due to complex formation. The mechanical studies of doped polymer films were carried out using universal testing machine (UTM at room temperature, indicating that the addition of the ZnO and WO3 with weight percentage concentration equal to 14% increases the tensile strength and Young’s modulus.

  9. Nanostructure and Formation Mechanism of PtWO3/C Nanocatalyst by Ethylene Glycol Method

    Institute of Scientific and Technical Information of China (English)

    WU Feng; LIU Yanhong; WU Chuan

    2011-01-01

    Pt-WO3 nanoparticles uniformly dispersed on Vulcan XC-72R carbon black were prepared by an ethylene glycol method. The morphology, composition, nanosturcture, electrochemical characteristics and electrocatalytic activity were characterized, and the formation mechanism was investigated. The average particle size was 2.3 nm, the same as that of Pt/C catalyst. The W/Pt atomic ratio was 1/20, much lower than the design of 1/3. The deposition of WO3·xH2O nanoparticles on Vulcan XC-72R carbon black was found to be very difficult by TEM. From XPS and XRD, the Pt nanoparticles were formed in the colloidal solution of Na2WO4,the EG insoluble Na2WO4 resulted in the decreased relative crystallinity and increased crystalline lattice constant compared with those of Pt/C catalyst and, subsequently, the higher specific electrocatalytic activity as determined by CV. The Pt-mass and Pt-electrochemically-active-specific-surface-area based anodic peak current densities for ethanol oxidation were 422.2 mA·mg-1Pt and 0.43 mA·cm-2Pt, 1.2 and 1.1 times higher than those of Pt/C catalyst, respectively.

  10. Synthesis, characterization and photocatalytic activity of porous WO{sub 3}/TiO{sub 2} hollow microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Liuyang [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Si, Zhichun, E-mail: emsztsinghua@126.com [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Weng, Duan [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); State Key Laboratory of New Ceramics and Fine Process, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Yao, Youwei [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2014-09-15

    Porous WO{sub 3}/TiO{sub 2} hollow microspheres were prepared by a spray drying method for photodegradation of methylene blue and phenol. The catalysts were characterized by X-ray diffraction, Field Emission Scanning Electron Microscope, High Resolution Transmission Electron Microscope, N{sub 2} adsorption–desorption measurements, Raman spectrometer, UV–Vis Diffuse Reflectance Spectroscopy and Zeta-Meter measurements. The results showed that the tungsten oxides mainly existed in highly dispersed amorphous form on anatase when the loading amount of tungsten oxide was below 3 mol%. The improved photocatalytic activity under UV light irradiation of the WO{sub 3}/TiO{sub 2} catalyst mainly arises from the enhanced charge separation efficiency rather than the improved light absorbance by highly dispersed amorphous tungsten oxides. Highly dispersed amorphous WO{sub x} can form a shallowly trapped site due to its similar band structure with TiO{sub 2}. The strongly electron-withdrawing of tungsten oxide in highly dispersed state facilitates the electron transition between titanium and WO{sub x}, and consequently improves the charge separation. The enhanced acidity of catalyst by WO{sub x} in reactant environment also improved the charge separation efficiency due to the timely transition of holes and electrons accumulated on TiO{sub 2} and WO{sub x}, respectively. However, the improved photocatalytic activity under visible light irradiation of the WO{sub 3}/TiO{sub 2} catalyst mainly arises from light harvest. TiO{sub 2} containing 3 mol% WO{sub 3} displayed the highest photocatalytic activity under UV light irradiation while that containing 4 mol% WO{sub 3} present highest activity under visible light irradiation.

  11. Phase relations and chemical vapor transport of hexagonal indium tungsten bronze In{sub x}WO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, Udo, E-mail: steiner@mw.htw-dresden.de

    2014-08-25

    Highlights: • Phase relations of hexagonal bronze In{sub x}WO{sub 3} with neighboring phases. • Chemical vapor transport experiments using NH{sub 4}Cl as transport agent. • Single crystals of In{sub x}WO{sub 3} up to a few mm in size were prepared. • Selective synthesis of crystals of the indium poor and indium rich phase boundary. - Abstract: Phase pure powder samples of hexagonal indium tungsten bronze In{sub x}WO{sub 3} (x = 0.25–0.35) were synthesized by solid state reaction at 1173 K. The phase relations of In{sub x}WO{sub 3} with neighboring binary and ternary phases were determined in the phase diagram In–W–O. Systematic chemical vapor transport experiments were carried out on source materials with compositions corresponding to miscellaneous two-phase and three-phase regions using NH{sub 4}X (X = Cl, Br, I) as transport agent. Crystals of hexagonal indium tungsten bronze were deposited beside In{sub 2}W{sub 3}O{sub 12} with composition corresponding to the indium poor phase boundary and dimensions up to a few mm in a temperature gradient 1173 K → 1073 K starting from ternary mixtures In{sub x}WO{sub 3}/In{sub 2}W{sub 3}O{sub 12}/In{sub 0.02}WO{sub 3}. Sole deposition of In{sub x}WO{sub 3} single crystals with composition x ≈ 0.33 was observed from ternary mixtures In{sub x}WO{sub 3}/W{sub 18}O{sub 49}/WO{sub 2} with a migration rate of about 0.5 mg/h (transport agent NH{sub 4}Cl)

  12. Preparation of three dimensional graphene foam–WO{sub 3} nanocomposite with enhanced visible light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Azimirad, R., E-mail: azimirad@yahoo.com; Safa, S.

    2015-07-15

    Three dimensional graphene foam (3D GF) was synthesized by chemical vapor deposition (CVD) on a nickel foam skeleton. After dissolving the nickel foam, the obtaining 3D GF was used as a highly porous conductive substrate for nucleation and growth of WO{sub 3} particles. Scanning electron microscopy (SEM) and Raman spectroscopy was employed to ensure the quality of the prepared GFs and to judge about the 3D GF–WO{sub 3} chemical structure. The WO{sub 3} characteristic Raman peaks centered at 726, and 809 cm{sup −1} are slightly broadened and displaced to lower wavelength in the 3D GF–WO{sub 3} nanocomposite, as compared to the corresponding peaks of the bare tungsten oxide. This phenomenon confirms the formation of W–C and W–O–C bonds in composite material which is important for faster transferring the photoexcited electrons to graphene 3D network as an exceptional electron acceptor. The 3D GF−WO{sub 3} composite material was applied in photocatalytic degradation of Rhodamine B dye. It was observed that the annealed samples show an excellent photocatalytic performance relative to the as-prepared 3D GF−WO{sub 3} samples and bare WO{sub 3}, which is ascribed to the lower electron/hole recombination through the formation of W–C and W–O–C bonds. - Highlights: • 3D GF synthesized by CVD on a nickel foam as a highly porous conductive substrate. • WO{sub 3} nanoparticles coated on 3D GF by dip-coating. • 3D GF−WO{sub 3} shows an excellent photocatalytic degradation of Rhodamine B dye. • Better photocatalytic properties assigned to the formation of W–C and W–O–C bonds.

  13. Electrospun TiO2-WO3 Nanofibers for Photocatalytic Removal of Mercury%静电纺丝法制备TiO2-WO3纳米纤维及光催化脱汞的研究

    Institute of Scientific and Technical Information of China (English)

    袁媛; 张军营; 樊国祥; 赵永椿; 郑楚光

    2012-01-01

    TiO2 and TiO2-WO3 nanofibers were successfully prepared by electrospinning method. The nanofibers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) as well as Brunauer-Emmett-Teller (BET). TiO2-WO3 nanofibers were used to remove Hg° from simulated flue gas in the dark, under visible light and UV light respectively. The mercury removal efficiency under different light conditions, the optimum doping content of WO3 as well as the capability to oxidize Hg° for 8 cycles were tested. The results show that TiO2-WO3 nanofibers exhibit an anatase phase structure with average diameter of 200 nm. The UV-Vis absorption intensity of TiO2-WO3 significantly increases with increasing WO3 doping content. In addition, when the doping content of WO3 is 7%, the Hg° removal efficiency under UV irradiation could reach 100%. After the eighth cycles, the Hg° removal efficiency over TiO2-WO3 remains at 100%, which indicate that it is stable with prolonged use of the catalysts. The increased photocatalytic activity is attributed to the surface acidity and better photoelectron-hole separation.%采用静电纺丝法成功制备了TiO2-WO3纳米纤维,利用X-射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscopy,SEM)、紫外可见吸收光谱(ultraviolet-visible,UV-Vis)及比表面积及孔径分析仪(Brunauer-Emmett-Teller,BET)对其进行表征.使用制备的纤维脱除模拟烟气中的元素汞,研究了TiO2-WO3分别在无光、紫外光和可见光下的脱汞率;考察了WO3的最佳掺杂比;并分析了TiO2-WO3光催化脱汞的机制.结果表明TiO2-WO3纤维中TiO2以锐钛矿相形态存在,纤维的直径约为200nm;当WO3的掺杂含量为7%时,TiO2-WO3在紫外光下的汞脱除率可达到100%; TiO2-WO3脱汞效率的稳定性好,在420 min时紫外光下的脱汞率仍保持在100%.表面酸性和有效的电荷转移是TiO2-WO3纳米纤维光催化活性提高的主要原因.

  14. WO3薄膜的电致变色与响应时间机理研究%Response Time and Electrochromic Mechanism of WO3 Films

    Institute of Scientific and Technical Information of China (English)

    杨海刚; 宋桂林; 张基东; 王天兴; 常方高

    2011-01-01

    Nanoscaled tungsten oxide films were fabricated by reactive DC magnetron sputtering. The influence of deposition gas pressure on surface morphology and microstructure of tungsten oxides was studied. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to characterize the micro-structural of the prepared thin films. Electrochromic and response time properties were researched by simultaneous spectrophotometric and cyclic voltametric measurements of tungsten oxides. The investigation results showed that micro-porous nanostructure has strong effects on the electrochemical and chromogenic properties, which depending on the specific surface area. For deposition gas pressure being 4 Pa, the modulating range of the visible optical transmittance can reach 71. 6% , the colored response time is 5 s, and the bleached response time is 16 s.%采用直流反应磁控溅射方法制备了纳米WO3薄膜,研究了溅射气压对WO3薄膜的表面形貌和微结构的影响.利用X射线衍射仪和扫描电子显微镜对WO3的微结构进行了表征.采用紫外-可见分光光度计和循环伏安测试系统对样品的电致变色及响应时间性能进行了研究.结果表明,纳米WO3薄膜的微孔结构特征具有较大的比表面积,有利于改善其电致变色性能.当溅射气压为4Pa时,WO3薄膜在可见光区的电致变色平均调色范围达到了71.6%,并且其着色响应时间为5 s,漂白响应时间为16 s.

  15. The exchange bias effect in Ni/NiO and NiO nanoparticles

    Science.gov (United States)

    Kou, Angela; Feygenson, Mikhail; Kreno, Lauren; Patete, Jonathan; Tiano, Amanda; Zhang, Fen; Wong, Stanislaus; Aronson, Meigan

    2009-03-01

    We used magnetic measurements, X-ray diffraction, and HRTEM to study the exchange bias field in Ni/NiO and NiO nanoparticles made by a modified wet chemistry method. We oxidized re-dispersed powders of bare Ni nanoparticles in air at 400^oC and 900^oC. HRTEM showed that annealing at 900^oC of bare Ni nanoparticles led to the formation of exceptionally high quality NiO nanoparticles, resembling perfect bulk-like crystalline order. To our knowledge, there are no reports of NiO particles of such quality in the literature. The loop shift was 1000 Oe at 300K for the NiO nanoparticles, while it was only 120 Oe at 10K for the Ni/NiO nanoparticles. The difference is explained by the different origins of the loop shift in Ni/NiO and NiO nanoparticles. In Ni/NiO nanoparticles, the loop shift is associated with exchange interactions between ferromagnetic Ni and antiferromagnetic NiO. In NiO nanoparticles, however, the origin of the shift is an uneven number of ferromagnetic sublattices present in NiO nanoparticles, which interact differently with an applied magnetic field (Kodama, 1999).

  16. Quantum dots as mediators in gas sensing: A case study of CdS sensitized WO3 sensing composites

    Science.gov (United States)

    Concina, Isabella; Comini, Elisabetta; Kaciulis, Saulius; Sberveglieri, Giorgio

    2014-01-01

    In this study the proof of principle of the use of naked semiconductor directly generated on metal oxide surface as mediators in gas sensing is provided. Successive ionic layer absorption and reaction (SILAR) technique has been applied to sensitize a WO3 thin film with CdS quantum dots. Response to gases of bare WO3 is deeply modified: quantum dots dramatically increase the metal oxide conductance, otherwise rather poor, and modify the capability of detecting environmental pollutants, such as CO and NO2. A modified sensing mechanism is proposed to rationalize the mediation exerted by the semiconducting active layer on the interaction between gaseous species and WO3 surface.

  17. On the low-lying states of WO - A comparison with CrO and MoO

    Science.gov (United States)

    Nelin, C. J.; Bauschlicher, C. W., Jr.

    1985-01-01

    The four low-lying states of WO were investigated and compared with similar states of CrO and MoO. For all these systems the ground state is 5 Pi, but the ordering of the upper states is different between WO and either CrO or MoO. The difference in the state ordering arises in part from the fact that in WO all of the states are formed from W(+) in a d4S1 configuration, whereas in both CrO and MoO some states are formed from the d5 configuration and others from the d4S1 configuration.

  18. Growth,structural,thermal properties and spectroscopic characteristics of KTb(WO4)2 single crystal

    Institute of Scientific and Technical Information of China (English)

    LI Jing; WANG Jiyang; HAN Shujuan; GUO Yongjie; WANG Yongzheng

    2012-01-01

    KTb(WO4)2(KTW) single crystal with dimensions up to 30 mm×30 mm×10 mm was grown by the top-seeded solution growth (TSSG) method for the first time.The crystal structure was refined at room temperature by using single crystal X-ray diffraction data.Absorption and fluorescence spectra were measured at room temperature.The fluorescence lifetime of KTb(WO4)2 was 114 μs.The specific heat of the KTb(WO4)2 crystal was also measured at room temperature.

  19. Electrochemical and electrochromic properties of layer-by-layer films from WO(3) and chitosan.

    Science.gov (United States)

    Huguenin, Fritz; Gonzalez, Ernesto R; Oliveira, Osvaldo N

    2005-07-07

    The design of improved materials for electrochromic applications now involves extensive use of novel composites, thus requiring an investigation of the mechanisms responsible for electrochromism in these structures. Using films of WO(3) and chitosan produced with the layer-by-layer (LBL) technique, we demonstrate that characteristics such as the number of electrochemical active sites (K), the molar absorption coefficient (epsilon), and the electrochromic efficiency (eta) can be obtained using the quadratic logistic equation (QLE). The complexation ability between chitosan and WO(3) allowed the growth of visually uniform multilayers of the composite, with the same amount of material adsorbed in each deposition cycle. By fitting the absorbance changes (DeltaA) resulting from the electronic intervalence transfer from W(V) to W(VI) sites in four-bilayer LBL films of WO(3)/chitosan and WO(3)/chitosan with ethanol in the precursor dispersion, K was estimated to be ca. 5.5 x 10(-8) mol cm(-2) and 3.6 x 10(-8) mol cm(-2), respectively. The molar absorption coefficient and electrochromic efficiency vary with the charge injected because of the saturation of W(V) sites and the dissipation and feedback effects implicit in the QLE associated with ion-network interactions, such as the proton trapping effect. The LBL film of WO(3)/chitosan showed a smaller molar absorption coefficient and electrochromic efficiency than that containing ethanol because of a greater proton trapping effect for the LBL film with no ethanol. This enhanced trapping effect was seen as a decrease in the electronic flux involved in intervalence transfer in electrochemical impedance spectroscopy experiments.

  20. Study of Hydrogen Adsorption on Pt/WO3-ZrO2 through Pt Sites

    Institute of Scientific and Technical Information of China (English)

    Sugeng Triwahyono; Aishah Abdul Jalil; Hideshi Hattori

    2007-01-01

    The rate determining step and the energy barrier involved in hydrogen adsorption on Pt/WO3ZrO2 were studied based on the assumption that the hydrogen adsorption occurs only through Pt sites.The rate of hydrogen adsorption on Pt/WO3-ZrO2 Was measured in the adsorption temperature range of 323-573 K and an initial hydrogen pressure of 50 Torr.The rates of hydrogen uptake were very high for the initial few minutes and the adsorption continued for more than 5 h below 523 K.The hydrogen uptake far exceeded the H/Pt ratio of unity for all adsorption temperatures,indicating that the adsorption of hydrogen involved the dissociative adsorption of hydrogen on Pt sites to form hydrogen atoms.the spillover of hydrogen atoms onto the surface of the WO3-ZrO2 catalyst.the diffusion of spiltover hydrogen atom over the surface of the WO3-ZrO2 catalyst,and the formation of protonic acid site originated from hydrogen atom by releasing an electron in which the electron may react with a second hydrogen atom to form a hydride near the Lewis acid site.The rate determining step was the spillover with the activation energy of 12.3 kJ/mol.The rate of hydrogen adsorption cannot be expressed by the rate equation based on the assumption that the rate determining step is the surface diffusion.The activity of Pt/WO3-ZrO2 Was examined on n-heptane isomerization in which the increase of hydrogen partial pressure provided positive-effect on the conversion of n-heptane and negative-effect on the selectivity towards iso-heptane.

  1. Preparation of ultra-thin and high-quality WO3 compact layers and comparision of WO3 and TiO2 compact layer thickness in planar perovskite solar cells

    Science.gov (United States)

    Zhang, Jincheng; Shi, Chengwu; Chen, Junjun; Wang, Yanqing; Li, Mingqian

    2016-06-01

    In this paper, the ultra-thin and high-quality WO3 compact layers were successfully prepared by spin-coating-pyrolysis method using the tungsten isopropoxide solution in isopropanol. The influence of WO3 and TiO2 compact layer thickness on the photovoltaic performance of planar perovskite solar cells was systematically compared, and the interface charge transfer and recombination in planar perovskite solar cells with TiO2 compact layer was analyzed by electrochemical impedance spectroscopy. The results revealed that the optimum thickness of WO3 and TiO2 compact layer was 15 nm and 60 nm. The planar perovskite solar cell with 15 nm WO3 compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO2 compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency.

  2. 直流磁控溅射沉积WO3薄膜电致变色性能研究%THE ELECTROCHROMIC PROPERTIES OF WO3 THIN FILMS BY DC MAGNETRON SPUTTERING

    Institute of Scientific and Technical Information of China (English)

    何延春; 邱家稳

    2007-01-01

    以金属钨为靶材,采用直流反应磁控溅射方法,在玻璃上制备电致变色WO3薄膜.利用X射线衍射(XRD)方法对薄膜的结构进行了分析,得出了WO3薄膜的沉积工艺.制备了WO3/TTO/Glass电致变色器件,并对其性能进行了研究.结果表明:在Li+注入前后,薄膜的透射率平均变化约50%,具有较好的可逆变色特性;Li+注入后,WO3薄膜中的一部分W6+变为W5+,转化比例约为25%.

  3. l376wo.m77t - MGD77 data file for Geophysical data from field activity L-3-76-WO in Washington to Vancouver Island, British Columbia from 06/11/1976 to 06/20/1976

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-3-76-WO in Washington to Vancouver...

  4. Synthesis and characterization of F-doped Cs0.33WO3-xFx particles with improved near infrared shielding ability

    Science.gov (United States)

    Liu, Jingxiao; Luo, Jiayu; Shi, Fei; Liu, Suhua; Fan, Chuanyan; Xu, Qiang; Shao, Guolin

    2015-01-01

    F-doped Cs0.33WO3-xFx particles were successfully synthesized by the hydrothermal method with hydrofluoric acid as fluorine source, and a new kind of heat insulating films were prepared from dispersion of Cs0.33WO3-xFx nanoparticles in polyvinyl alcohol (PVA) aqueous solution. The effects of F doping on the crystal structure and morphology of Cs0.33WO3-xFx particles as well as the near-infrared (NIR) shielding ability and heat insulation properties of Cs0.33WO3-xFx films were investigated. The results indicated that HF acid addition could promote the formation of rod-like Cs0.33WO3-xFx particles during hydrothermal synthesis and increase the yield of Cs0.33WO3-xFx powders. Moreover, the as-prepared films from dispersion solution of Cs0.33WO3-xFx particles exhibited higher near-infrared (NIR) shielding ability and heat insulating properties than that of the undoped Cs0.33WO3 film. Particularly, the as-prepared Cs0.33WO3-xFx sample with F/W (molar ratio)=0.45 showed best NIR shielding ability and transparent heat insulating performance. The formation mechanism of nanorod-like particles and the effects of F doping on the properties of Cs0.33WO3-xFx products were discussed.

  5. Forskolin-induced differentiation of BeWo cells stimulates increased tumor growth in the chorioallantoic membrane (CAM) of the turkey (Meleagris gallopavo) egg.

    Science.gov (United States)

    Schneider, Ralf; Borges, Marcus; Kadyrov, Mamed

    2011-05-01

    Invasiveness of BeWo cells has been assessed in a variety of assay systems including matrigel and mouse. At the same time BeWo cells are mostly used as model system for trophoblast fusion. Here we aimed to test the properties of BeWo cells in a combined approach. We forced BeWo cells to differentiate by culturing the cells in the presence of forskolin and then used these cells for invasion assays on the chorioallantoic membrane (CAM) of the turkey. The chorioallantoic membranes of turkey eggs were incubated with medium containing forskolin, BeWo cells cultured in medium alone, BeWo cells cultured in forskolin and washed, and BeWo cells cultured in forskolin and used directly for application. Suspensions were applied onto ten CAM per condition. For local tumor formation eggs were checked for tumor development every 24h macroscopically for up to 12 days and immunohistochemistry for cytokeratin 18 and Ki-67 were used for further analysis. Forskolin alone did not have any deleterious effect on the CAM. When the CAM was incubated with BeWo cells cultured in medium 40% of the eggs developed a macroscopically visible tumor. BeWo cells stimulated with forskolin and washed induced tumor growth in 50% of the eggs, while forskolin stimulated BeWo cells applied directly onto the CAM induced tumor growth in 70% of the eggs. Forced differentiation of BeWo cells by forskolin may lead to syncytial fusion in a plastic culture dish. Under the conditions used here, i.e. in direct contact to a living tissue, forskolin-induced differentiation of BeWo cells leads to an increase in tumor formation in the CAM. Thus BeWo cells may use signaling pathways to decide for both differentiation pathways similar to primary trophoblast depending on the environment.

  6. Preparation of Ag/Bi2 WO6 and Photocatalysis Oxidation Property%Ag/Bi2 WO6的制备及光催化氧化性能

    Institute of Scientific and Technical Information of China (English)

    杨芬; 朱勋乐

    2014-01-01

    以Bi(NO3)3·5H2O、 Na2WO4·2H2O、 AgNO3为原料,利用液相沉淀法制备Bi2WO6及Ag掺杂Bi2WO6光催化剂,以亚甲基蓝溶液为目标降解物,对其降解效率进行研究。研究结果表明,当亚甲基蓝溶液的浓度为15 mg/L,体积为50 mL,降解时间3.5 h, Bi2 WO6降解率仅为55%;当Ag/Bi摩尔比为0.4%时, Ag/Bi2 WO6表现出较好的催化性能,相同时间降解率达到97%。%Ag/Bi2 WO6 with highly efficient photocatalytic activity under visible light irradition were synthesized using Bi(NO3)3·5H2O, Na2WO4·2H2O, and AgNO3 as starting materials. The degradation efficiency of methylene blue was studied. The results showed that Ag/Bi2 WO6 with 0. 4% mole ratio had a higher photocatalytic activity, the 97%degradation of methylene blue (15 mg/L) was obtained after visible light irradiation for 3. 5 h.

  7. Bridging exchange bias effect in NiO and Ni(core)@NiO(shell) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rinaldi-Montes, Natalia, E-mail: nataliarin@gmail.com [Departamento de Física, Universidad de Oviedo, E-33007 Oviedo (Spain); Gorria, Pedro [Departamento de Física & IUTA, EPI, Universidad de Oviedo, E-33203 Gijón (Spain); Martínez-Blanco, David [Servicios Científico-Técnicos, Universidad de Oviedo, E-33006 Oviedo (Spain); Fuertes, Antonio B. [Instituto Nacional del Carbón, CSIC, E-33080 Oviedo (Spain); Fernández Barquín, Luis [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, E-39005 Santander (Spain); Puente-Orench, Inés [Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza and Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France); Blanco, Jesús A. [Departamento de Física, Universidad de Oviedo, E-33007 Oviedo (Spain)

    2016-02-15

    Among all bi-magnetic core(transition metal)@shell(transition metal oxide) nanoparticles (NPs), Ni@NiO ones show an onset temperature for the exchange bias (EB) effect far below the Néel temperature of bulk antiferromagnetic NiO. In this framework, the role played by the magnetism of NiO at the nanoscale is investigated by comparing the microstructure and magnetic properties of NiO and Ni@NiO NPs. With the aim of bridging the two systems, the diameter of the NiO NPs (~4 nm) is chosen to be comparable to the shell thickness of Ni@NiO ones (~2 nm). The EB effect in Ni@NiO NPs is attributed to the exchange coupling between the core and the shell, with an interfacial exchange energy of ΔE~0.06 erg cm{sup −2}, thus comparable to previous reports on Ni/NiO interfaces both in thin film and NP morphologies. In contrast, the EB detected in NiO NPs is explained in a picture where uncompensated spins located on a magnetically disordered surface shell are exchange coupled to the antiferromagnetic core. In all the studied NPs, the variation of the EB field as a function of temperature is described according to a negative exponential law with a similar decay constant, yielding a vanishing EB effect around T~40–50 K. In addition, the onset temperature for the EB effect in both NiO and Ni@NiO NPs seems to follow a universal dependence with the NiO crystallite size. - Highlights: • Comparison of the exchange bias effect in NiO and Ni(core)@NiO(shell) nanoparticles. • Universal temperature dependence of the exchange bias effect. • Suggested similar physical origin of the effect in both systems. • Size and crystallinity of the NiO shell hold the key for exchange bias properties.

  8. Pd Nanoparticles Coupled to WO 2.72 Nanorods for Enhanced Electrochemical Oxidation of Formic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Zheng; Erdosy, Daniel P.; Mendoza-Garcia, Adriana; Duchesne, Paul N.; Li, Junrui; Muzzio, Michelle; Li, Qing; Zhang, Peng; Sun, Shouheng (Brown); (Dalhousie U.); (Huazhong)

    2017-03-02

    We synthesize a new type of hybrid Pd/WO2.72 structure with 5 nm Pd nanoparticles (NPs) anchored on 50 × 5 nm WO2.72 nanorods. The strong Pd/WO2.72 coupling results in the lattice expansion of Pd from 0.23 to 0.27 nm and the decrease of Pd surface electron density. As a result, the Pd/WO2.72 shows much enhanced catalysis toward electrochemical oxidation of formic acid in 0.1 M HClO4; it has a mass activity of ~1600 mA/mgPd in a broad potential range of 0.4–0.85 V (vs RHE) and shows no obvious activity loss after a 12 h chronoamperometry test at 0.4 V. Our work demonstrates an important strategy to enhance Pd NP catalyst efficiency for energy conversion reactions.

  9. Enhanced Colouration Efficiency of Pulsed DC Magnetron Sputtered WO3 Films Cycled in H2SO4 Electrolyte Solution

    Directory of Open Access Journals (Sweden)

    K. Punitha

    2014-01-01

    Full Text Available In the present investigation, we report on DC power and pulsing frequency induced changes in electrochromic properties of pulsed DC magnetron sputtered WO3 films by intercalating/deintercalating H+ ions from 0.1 M H2SO4 electrolyte solution. The observed efficient colouration ↔ bleaching mechanism of WO3 films confirms the effective electrochromic nature of the films associated with the electrochemical intercalation/deintercalation of H+ ions and electrons into WO3 lattice. The higher optical modulation was observed in the visible region of the optical transmittance spectra of colored and bleached WO3 films. The maximum coloration efficiency of 79 cm2/C was observed the first time for the film deposited at a DC power of 150 W and a pulsing frequency of 25 kHz.

  10. One-dimensional Z-scheme TiO2/WO3/Pt heterostructures for enhanced hydrogen generation

    Science.gov (United States)

    Gao, Hongqing; Zhang, Peng; Hu, Junhua; Pan, Jimin; Fan, Jiajie; Shao, Guosheng

    2017-01-01

    One-dimensional Z-scheme TiO2/WO3/Pt heterostructures were fabricated by integrating a facile electrospinning technique and subsequent annealing in air. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy, were used to characterize the as-fabricated samples. The results showed that the H2-generation of the as-fabricated one-dimensional Z-scheme TiO2/WO3/Pt heterostructures (S2) was greatly enhanced compared with pure TiO2 nanofibers (S0) and TiO2/WO3 nanofibers (S1). The enhanced photocatalyst activities were mainly attributed to the solid-state Z-scheme photosynthetic heterojunction system with Pt nanoparticle as an electron collector and WO3 as a hole collector, leading to effective charge separation on these semiconductors, which were evidenced by electrochemical impedance spectroscopy (EIS) and photocurrent analysis.

  11. CTAB-Assisted Hydrothermal Synthesis of WO3 Hierarchical Porous Structures and Investigation of Their Sensing Properties

    Directory of Open Access Journals (Sweden)

    Dan Meng

    2015-01-01

    Full Text Available WO3 hierarchical porous structures were successfully synthesized via cetyltrimethylammonium bromide- (CTAB- assisted hydrothermal method. The structure and morphology were investigated using scanning electron microscope, X-ray diffractometer, transmission electron microscopy, X-ray photoelectron spectra, Brunauer-Emmett-Teller nitrogen adsorption-desorption, and thermogravimetry and differential thermal analysis. The result demonstrated that WO3 hierarchical porous structures with an orthorhombic structure were constructed by a number of nanoparticles about 50–100 nm in diameters. The H2 gas sensing measurements showed that well-defined WO3 hierarchical porous structures with a large specific surface area exhibited the higher sensitivity compared with products without CTAB at all operating temperatures. Moreover, the reversible and fast response to H2 gas and good selectivity were obtained. The results indicated that the WO3 hierarchical porous structures are promising materials for gas sensors.

  12. Electrosprayed heterojunction WO3/BiVO4 films with nanotextured pillar structure for enhanced photoelectrochemical water splitting

    Science.gov (United States)

    Mali, Mukund G.; Yoon, Hyun; Kim, Min-woo; Swihart, Mark T.; Al-Deyab, Salem S.; Yoon, Sam S.

    2015-04-01

    We demonstrate that the addition of a tungsten oxide (WO3) layer beneath a bismuth vanadate (BiVO4) photocatalyst layer with a nanotextured pillar morphology significantly increases the photocurrent density in photoelectrochemical water splitting. The WO3-BiVO4 bilayer films produced a photocurrent of up to 3.3 mA/cm2 under illumination at 100 mW/cm2 (AM1.5 spectrum). The bilayer film was characterized by scanning electron microscopy, X-ray diffraction, and photoelectrochemical methods, which confirmed the superiority of the bilayer film in terms of its morphology and charge separation and transport ability. Both WO3 and BiVO4 were deposited by electrostatic spraying under open-air conditions, which resulted in nanotextured pillars of BiVO4 atop a smooth WO3 film. The optimal coating conditions are also reported.

  13. Structural and optical modifications of the Ag2WO4/CoPc nanocomposite for potential applications

    Science.gov (United States)

    Sreedevi, A.; Priyanka, K. P.; Babitha, K. K.; Jaseentha, O. P.; Varghese, Thomas

    2016-01-01

    The silver tungstate/cobalt phthalocyanine nanocomposite (Ag2WO4/CoPc was prepared by the simple solvent evaporation method. The as-synthesized nanocomposite was characterized by thermo gravimetric and differential thermal analysis, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, photoluminescence spectroscopy and Raman spectroscopy. The structural characterization confirms the formation of the Ag2WO4/CoPc nanocomposite. The ultraviolet-visible spectrum for the Ag2WO4/CoPc nanocomposite shows extended visible absorption in the wavelength range 670-735nm. Photoluminescence spectrum of the nanocomposite shows large intensity and violet-blue emission when excited with near-ultraviolet light. The present study suggests that the synthesized Ag2WO4/CoPc nanocomposite can be a promising material for constructing light emitting diodes, solar cells and optoelectronic devices.

  14. Saucer-and Rod-like WO_3 3-D Microstructures:Synthesis,Characterization,and Optical Properties

    Institute of Scientific and Technical Information of China (English)

    CHEN Lin; YAN Ting-Jiang; ZHENG Jing; LI Li-Ping

    2011-01-01

    Three-dimensional(3-D)saucer-and rod-like WO3 microstructures have been synthesized by a simple hydrothermal route using tartaric acid as the assistant agent.X-ray powder diffraction(XRD)patterns indicate that the as-prepared samples are the pure hexagonal phase WO3.The morphologies are characterized by scanning electron microscope(SEM)and are found to be highly sensitized to the reaction temperature.A probable formation mechanism of the WO3 microstructures from saucer-like at low temperatures to rod-like at high temperatures is proposed.The optical properties of the novel WO3 microstructures are studied by UV-vis diffuse reflectance spectroscopy(DRS).The mechanism of strong absorption at visible region and red shift of calcined sample is also discussed.

  15. Convenient synthesis of twin-Christmas tree-like PbWO4 microcrystals and their photocatalytic properties

    Science.gov (United States)

    Zhang, Jin; Peng, Li-Li; Tang, Ying; Wu, Huijie

    2017-06-01

    Novel twin-Christmas tree-like PbWO4 microcrystals have been prepared via a convenient aqueous solution route at room temperature under the assistance of β-cyclodextrin (β-CD). The product was characterized by XRD, EDX, SEM, TEM, UV-vis and PL and BET techniques. It was found that β-CD plays an important role in the forming of twin-Christmas tree-like PbWO4 microcrystals. A five-step growth mechanism was proposed to explain the formation of such twin-Christmas tree-like structures. The photocatalytic performance of PbWO4 microcrystals was evaluated by measuring the decomposition rate of methylene blue (MB) and malachite green (MG) solution under the UV irradiation, and the photocatalytic results indicated that as-prepared PbWO4 microcrystals exhibit good and versatile photocatalytic activity as well as excellent recyclability.

  16. Correction: Iron-doping-enhanced photoelectrochemical water splitting performance of nanostructured WO3: a combined experimental and theoretical study.

    Science.gov (United States)

    Zhang, Teng; Zhu, Zonglong; Chen, Haining; Bai, Yang; Xiao, Shuang; Zheng, Xiaoli; Xue, Qingzhong; Yang, Shihe

    2015-09-07

    Correction for 'Iron-doping-enhanced photoelectrochemical water splitting performance of nanostructured WO3: a combined experimental and theoretical study' by Teng Zhang et al., Nanoscale, 2015, 7, 2933-2940.

  17. Effect of Oral Administration of Tungsten Trioxide (WO3) Particles on Hispathological Feature of liver and kidney in Rat

    Science.gov (United States)

    Munawaroh, H. S. H.; Nandiyanto, A. B. D.; Gumilar, G. G.; Widi, A.; Subangkit, M.

    2017-03-01

    This study aims to investigate the toxicity and histopathology of tungsten trioxide (WO3) administration on rat’s liver and kidney. The LD50 of WO3 was determined and the sub acute toxicity was evaluated by orally administration of 5000 mg kg-1 of WO3 to rat for 14 consecutive days. Parameter of blood cells, ALT, creatinine, and BUN were experimentally measured. The toxicological evaluation showed that WO3 is a non toxic compound with the LD50 higher that 5000 mg kg-1. No biochemical change was observed for creatinine and Blood Urea Nitrogen parameter. In contrast, ALT parameter shows higher value in the experiment than that in the control group. Histopathological changes on rat’s liver and kidney were also studied. Small defects in rat’s liver and kidney were found, which may interfere the functional of related enzymes.

  18. OpenNI cookbook

    CERN Document Server

    Falahati, Soroush

    2013-01-01

    This is a Cookbook with plenty of practical recipes enriched with explained code and relevant screenshots to ease your learning curve. If you are a beginner or a professional in NIUI and want to write serious applications or games, then this book is for you. Even OpenNI 1 and OpenNI 1.x programmers who want to move to new versions of OpenNI can use this book as a starting point. This book uses C++ as the primary language but there are some examples in C# and Java too, so you need to have about a basic working knowledge of C or C++ for most cases.

  19. Magnetic Properties of Ni Nanoparticles and Ni(C) Nanocapsules

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Structure and magnetic properties of Ni nanoparticles and Ni(C) nanocapsules were studied. The carbon atoms hardly affect the lattice of Ni to form Ni-C solid solution or nickel carbides. The large thermal irreversibility in zerofield-cooled and zero-field magnetization curves indicates magnetic blocking with a wide energy barrier. Saturation magnetization, remanent magnetization and coercivity of Ni(C) nanocapsules decrease with increasing temperature.

  20. Hollow Sodium Tungsten Bronze (Na0.15WO3) Nanospheres: Preparation, Characterization, and Their Adsorption Properties

    OpenAIRE

    Zuo Guanke; Guo He; Liu Hui; Zhang Jingyan; Hou Jing; Shen Guangxia; Cheng Ping; Guo Shouwu

    2009-01-01

    Abstract We report herein a facile method for the preparation of sodium tungsten bronzes hollow nanospheres using hydrogen gas bubbles as reactant for chemical reduction of tungstate to tungsten and as template for the formation of hollow nanospheres at the same time. The chemical composition and the crystalline state of the as-prepared hollow Na0.15WO3nanospheres were characterized complementarily, and the hollow structure formation mechanism was proposed. The hollow Na0.15WO3nanospheres sho...

  1. Search for 2{\\beta} decay of 116Cd with the help of enriched 116CdWO4 crystal scintillators

    CERN Document Server

    Poda, D V; Belli, P; Bernabei, R; Cappella, F; Caracciolo, V; Castellano, S; Chernyak, D M; Cerulli, R; Danevich, F A; d'Angelo, S; Incicchitti, A; Kobychev, V V; Konovalov, S I; Laubenstein, M; Podviyanuk, R B; Polischuk, O G; Shlegel, V N; Tretyak, V I; Umatov, V I; Vasiliev, Ya V

    2014-01-01

    Cadmium tungstate crystal scintillators enriched in $^{116}$Cd to 82% ($^{116}$CdWO$_4$, total mass of $\\approx$1.2 kg) are used to search for 2$\\beta$ decay of $^{116}$Cd deep underground at the Gran Sasso National Laboratory of the INFN (Italy). The radioactive contamination of the $^{116}$CdWO$_4$ crystals has been studied carefully to reconstruct the background of the detector. The measured half-life of $^{116}$Cd relatively to 2$\

  2. Optical properties of hydrated tungsten trioxide 3WO{sub 3}·H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Valyukh, I. [Laboratory of Applied Optics, Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping (Sweden); Jiao, Z. [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Arwin, H. [Laboratory of Applied Optics, Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping (Sweden); Sun, X.W. [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)

    2014-11-28

    Spectroscopic ellipsometry was used to determine the optical properties of plate-like hydrated tungsten trioxide (3WO{sub 3}·H{sub 2}O) films in the energy range 300–4000 cm{sup −1}. Films with different thicknesses were deposited on glass substrates pre-coated with fluorine-doped tin oxide via an efficient and simple hydrothermal method. Parametric models were used to extract thicknesses and optical constants of the thin films. The WO{sub 3} was found to be more hydrated for thicker films. Moreover, the nano-plates are larger in thicker films, which leads to a decrease of the transmission due to an increase of the scattering. Features in the obtained dielectric functions of the 3WO{sub 3}·H{sub 2}O thin films were compared with the earlier published optical spectra of WO{sub 3} and its hydrates ½WO{sub 3}·H{sub 2}O and WO{sub 3}·H{sub 2}O. - Highlights: • 3WO{sub 3}·H{sub 2}O films with different thickness grown on FTO glass by hydrothermal deposition. • The optical properties in infrared were studied by spectroscopic ellipsometry. • The presence of ½WO{sub 3}·H{sub 2}O compounds in the films is observed. • Films retain a great amount of water. • Thicker films scatter more light due to the larger size of the nano-plates.

  3. Thermochemical methane reforming using WO{sub 3} as an oxidant below 1173 K by a solar furnace simulator

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, T.; Shimizu, K. [Niigata Univ., Graduate School of Science and Technology, Niigata (Japan); Kitayama, Y.; Kodama, T. [Niigata Univ., Dept. of Chemistry and Chemical Engineering, Niigata (Japan)

    2001-07-01

    Thermochemical methane reforming by a reactive redox system of WO{sub 3} was demonstrated under direct irradiation of the metal oxide by a concentrated, solar-simulated Xe-lamp beam below 1173 K, for the purpose of converting solar high-temperature heat to chemical fuels. In the proposed cycling redox process, the metal oxide is expected to react with methane as an oxidant to produce syngas with a H{sub 2}/CO ratio of two, which is suitable for the production of methanol, and the reduced metal oxide which is oxidised back with steam in a separate step to generate hydrogen uncontaminated with carbon oxide. The ZrO{sub 2}-supported WO{sub 3} gave about 45% of CO yield and 55% of H{sub 2} yield with a H{sub 2}/CO ratio of about 2.4 in a temperature range of 1080-1160 K at a W/F ratio of 0.167 g min Ncm {sup -3} (W is the weight of WO{sub 3} phase and F is the flow rate of CH{sub 4}). The activity data under the solar simulation were compared to those for the WO{sub 3}/ZrO{sub 2} heated by irradiation of an infrared light. This comparison indicated that the CO selectivity was much improved to 76-85% in the solar-simulated methane reforming, probably by photochemical effect due to WO{sub 3} phase. The main solid product of WO{sub 2} in the reduced WO{sub 3}/ZrO{sub 2} was reoxidised to WO{sub 3} with steam to generate hydrogen below 1173 K. (Author)

  4. Luminescent properties of red-light-emitting phosphors CaWO4 : Eu3+, Li+ for near UV LED

    Indian Academy of Sciences (India)

    F B Xiong; H F Lin; L J Wang; H X Shen; Y P Wang; W Z Zhu

    2015-12-01

    A series of red phosphors Ca1−2WO4 : Eu3+, Li+ ( = 0.01, 0.02, 0.04, 0.06, 0.12, 0.20 and 0.30) in pure phase were synthesized via high-temperature solid-state reaction and their luminescent properties were investigated. For comparison, the 6 mol% Eu3+-doped CaWO4 was also obtained and investigated. The crystal structures of these phosphors were characterized by powder X-ray diffraction, and the luminescent properties of Eu3+-, Li+-codoped CaWO4 were investigated by diffuse reflectance spectra, photoluminescence emission spectra, photoluminescence excitation spectra, and the Commission International de L' Eclairage (CIE) chromaticity indexes. These spectra illustrated that Eu3+-, Li+-codoped CaWO4 phosphors could effectively be excited by a 270 nm ultraviolet (UV) or 394 nm near UV chip, and exhibit red emission originated from the 5D0 $\\rightarrow$ 7F ( = 1 and 2) transitions of Eu3+. The fluorescent intensities of red emission band centred at 610 nm of 6 mol% Eu3+-, Li+-codoped CaWO4 were about 1.27 times stronger than that of 6 mol% Eu3+-doped CaWO4 under 394 nm excitation. The 12 mol% doping concentration of Eu3+ ions in CaWO4 is optimum when excited at 394 nm, while excited at 270 nm the sample with 6 mol% was the best one. The concentration quenching mechanism could be attributed to the dipole–dipole interaction between the Eu3+ ions. The CIE colour coordinates can be tuned from yellowish red to deep red with varying concentrations of Eu3+. The present work suggests that Eu3+-, Li+-codoped CaWO4 as red phosphors exhibit great potential application in the near UV excited white-light-emitting diode.

  5. Highly Sensitive Rayleigh Wave Hydrogen Sensors with WO3 Sensing Layers at Room Temperature

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng; FAN Li; ZHANG Shu-Yi; YANG Yue-Tao; ZHOU Ding-Mao; SHUI Xiu-Ji

    2011-01-01

    Rayleigh wave hydrogen sensors based on 128° YX-LiNbO3 substrates with WO3 sensing layers operating at room temperature are studied.The experimental results indicate that the WO3 layers obtained by a sol-gel method have much higher sensitivities because the sensing layers produced by the sol-gel method have small grains and high roughness and porosity.It is also confirmed that in the sol-gel method,keeping WO3 solutions at low temperature and/or decreasing the viscosity of the solutions can decrease the grain sizes and increase the hydrogen-absorbability of the sensing layer.Under the optimized preparation conditions,the high sensitivity of the hydrogen sensors at room temperature is obtained,in which 1% hydrogen in natural air induces the frequency shift of 72 kHz at the operating frequency of 124.2 MHz.Surface acoustic wave (SAW) hydrogen sensors have attracted a great deal of attention so far,in which the sensors have achieved high sensitivity as the sensors were often operated at high temperature,such as higher than 100℃.[1-4] However,in these experiments,a heater and a thermostat were required,which induced the sensors to be more complicated and unfavorable for miniaturization,and limited their application at room temperature.Furthermore,the heater can induce extra power loss and risks of fire and explosion.%Rayleigh wave hydrogen sensors based on 128° YX-LiNbO3 substrates with WO3 sensing layers operating at room temperature are studied. The experimental results indicate that the WO3 layers obtained by a sol-gel method have much higher sensitivities because the sensing layers produced by the sol-gel method have small grains and high roughness and porosity. It is also confirmed that in the sol-gel method, keeping WO3 solutions at low temperature and/or decreasing the viscosity of the solutions can decrease the grain sizes and increase the hydrogen-absorbability of the sensing layer. Under the optimized preparation conditions, the high sensitivity of the

  6. Experimental studies on a Savonius rotor with casing; Casing wo motsu Savonius gata turbine no tokusei ni kansuru jikkenteki kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Tan, S. [Tsuruoka National College of Technology, Yamagata (Japan); Shimizu, Y. [Mie University, Mie (Japan). Faculty of Engineering; Kikuyama, K. [Nagoya University, Nagoya (Japan). Faculty of Engineering

    1997-07-25

    The Savonius turbine, which works at low rotatory speeds and gives a high degree of torque, has been used for a wind turbines. In order to examine the feasibility of applying the turbine as a wave energy conversion system, a Savonius rotor was installed in a casing and its performance was studied experimentally to examine the various geometrical configurations of the rotor and casing. When optimally configured, the turbine exhibits higher efficiency than a wind turbine without a casing during steady flow conditions. 6 refs., 17 figs., 1 tab.

  7. Lightning arrester models enabling highly accurate lightning surge analysis; Koseidona kaminari surge kaiseki wo kano ni suru hiraiki model

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, T. [Chubu Electric Power Co. Inc., Nagoya (Japan); Funabashi, T.; Hagiwara, T.; Watanabe, H. [Meidensha Corp., Tokyo (Japan)

    1998-12-28

    Introduced herein are a dynamic behavior model for lightning arresters designed for power stations and substations and a flashover model for a lightning arresting device designed for transmission, both developed by the author et al. The author et al base their zinc oxide type lightning arrester model on the conventional static V-I characteristics, and supplement them with difference in voltage between static and dynamic characteristics. The model is easily simulated using EMTP (Electromagnetic Transients Program) etc. There is good agreement between the results of calculation performed using this model and actually measured values. Lightning arresting devices for transmission have come into practical use, and their effectiveness is introduced on various occasions. For the proper application of such devices, an analysis model capable of faithfully describing the flashover characteristics of arcing horns installed in great numbers along transmission lines, and of lightning arresting devices for transmission, are required. The author et al have newly developed a flashover model for the devices and uses the model for the analysis of lightning surges. It is found that the actually measured values of discharge characteristics of lightning arresting devices for transmission agree well with the values calculated by use of the model. (NEDO)

  8. On the purifying chamber which makes organic substance into the bio gasification; Yukibutsu wo baiogasuka suru jokaso ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Tanba, Fumio [Nagoya University, Aichi (Japan); Oseki, Hiroaki; Sakurai, Yoshimasa

    1999-03-31

    The total energy which the mankind uses is taken in as an energy for being effective by eating agricultural products got through the photosynthesis called 1/15000 of solar energy which falls on the earth, and the process must be to use this solar energy which produces excretory substance by collecting. It will be important that this process does not put on the failure in the earth either and that it closes it as possible keeping system. Various excreted organic substances are contained in the source excreted, and it can be simply made bio gasification they all and the maintenance also describe the easy purifying chamber. (NEDO)

  9. Discharge coefficient of poppet intake valve with rotating flow. Senkai kuki wo tomonau popetto kyukiben no ryuryo keisu ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, S.; Kashiwada, Y.; Waka, R. (Tottori Univ., Tottori (Japan). Faculty of Engineering); Liu, Guobang (Okayama Univ., Okayama (Japan). Graduate School)

    1994-04-25

    In recent years, there are many cases of usage of the intake system aiming at formation of swirls because of the demand for improvement of combustion of internal combustion engines. This study has the objective to examine experimentally the effect of the rotating strength on the discharge coefficient of an intake valve in the stationary flow by changing the strength of intake rotation around the valve axis in case when the air is running into the cylinder while rotating around the intake valve axis. The information obtained as a result is as follows; at a part where the valve head is small, the effect of the rotation in the upper flow of the valve on the discharge coefficient is small, but as the valve head becomes bigger, the effect of rotation increases, and as the rotation is stronger, the flow coefficient becomes less. In case when the valve head angle is 0[degree], the discharge coefficient at the low valve head becomes bigger than the case when the valve head angle is 20[degree]. Concerning the discharge coefficient obtained from the difference between the pressure in the cylinder and the atmospheric pressure, in case when the valve head is small, the discharge coefficient becomes big since the theoretical air capacity is estimated less due to the pressure recovery. 7 refs., 13 figs.

  10. Prediction of strong acceleration motion depended on focal mechanism; Shingen mechanism wo koryoshita jishindo yosoku ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Kaneda, Y.; Ejiri, J. [Obayashi Corp., Tokyo (Japan)

    1996-10-01

    This paper describes simulation results of strong acceleration motion with varying uncertain fault parameters mainly for a fault model of Hyogo-ken Nanbu earthquake. For the analysis, based on the fault parameters, the strong acceleration motion was simulated using the radiation patterns and the breaking time difference of composite faults as parameters. A statistic waveform composition method was used for the simulation. For the theoretical radiation patterns, directivity was emphasized which depended on the strike of faults, and the maximum acceleration was more than 220 gal. While, for the homogeneous radiation patterns, the maximum accelerations were isotopically distributed around the fault as a center. For variations in the maximum acceleration and the predominant frequency due to the breaking time difference of three faults, the response spectral value of maximum/minimum was about 1.7 times. From the viewpoint of seismic disaster prevention, underground structures including potential faults and non-arranging properties can be grasped using this simulation. Significance of the prediction of strong acceleration motion was also provided through this simulation using uncertain factors, such as breaking time of composite faults, as parameters. 4 refs., 4 figs., 1 tab.

  11. Acquisition of useful and high ability genes for acidophilic bacteria; Kosansei saikin ni takai noryoku wo fuyosuru idenshi no kakutoku

    Energy Technology Data Exchange (ETDEWEB)

    Senda, T.; Inoue, C.; Shinbori, Y. [Tohoku University, Sendai (Japan)

    1997-02-01

    This effort aims at the development of high-performance bacteria usable in bio-leaching in metal smelting by acquiring genes capable of realizing such. A method is used of choosing some isolated strains exhibiting high-performance traits and acquiring target genes therefrom by use of genetic engineering. Approximately 200 kinds in the aggregate of acidophilic bacteria are currently available for the study, including isolated iron-oxidizing and sulfur-oxidizing bacteria, standard species acquired for the study, and strains previously isolated by the laboratory. The bacteria are tested with respect to their Fe{sup 2+}-oxidizing rates, sulfur-oxidizing capabilities, and strength to withstand inhibiting substances (Ag{sup +}, Cl{sup -}, Mo{sup 6+}, etc.), which results in the nomination of 8 strains. The study planned to follow includes processes involving the extraction of chromosome DNAs from the 8 strains and their refinement, gene cloning by the Southern hybridization method, determination of their base sequences, determination of the difference between the strains in point of gene expression, and investigations of the relations that the results of these processes bear toward the said high-performance traits. Also under way is a study about the infuence-exerting factors revealed during the evaluation of the abilities of acidphlic bacteria. 2 refs., 2 tabs.

  12. Hydrogen production from garbage by the bacterium enterobacter aerogenes; Daidokoro no namagomi wo riyoshita bakuteria ni yoru suiso seisan

    Energy Technology Data Exchange (ETDEWEB)

    Tanisho, S.; Fujii, Y. [Yokohama National Univ. (Japan). Faculty of Engineering

    1995-09-01

    This writer, aiming at hydrogen production by fermentation using biomass, has studied production from various carbohydrates, organic acids and alcohols by using Enterobacter aerogenes strain E.82005 which bacterium was picked from leaves of four-o`clock and has high ability of hydrogen production. This bacterium being facultative anaerobic, it need not intercept O2, and the gas generated from its common culture solution which contains inorganic ingredients (YNOB3), peptone and glucose was composed of only H2 and CO2. As the tests for kitchen garbage, from each garbage of apples, oranges, bananas and spinage, H2 were obtained at the rate of 0.51, 0.27, 0.09 and 0.15 m mol/g respectively. Guts of fishes, tofu, tofu-refuse and eggs were alternative nitrogen sources of peptone. Especially, miso, soy sauce and soybean flour were very good substrates for hydrogen production as well as good nitrogen sources. 7 refs., 6 figs., 3 tabs.

  13. ICEP provides information of oil exploitation and developments; Sekiyu no tanko kaihatsu ni ICEP no isso no katsuyo wo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    Described herein are organization and activities of Information Center for Petroleum Exploitation and Production (ICEP), a foundation established in April 1992, in the form of interview with the president as the interviewee. It consists of departments of general affairs, researches and business, having some 20 staff members loaned from Petroleum Corporation and Petroleum Development Corporation. A larger number of loanees from private enterprises are working for Research Department, a central section of the organization, responsible for surveys and researches of oil exploitation and development techniques, information collection, and analyses of world oil policies and economics which serve as the backgrounds for oil projects. ICEP supplies a variety of databases, of which PEPD/IRIS21 is used most frequently. It provides world oil exploitation, development and production data, which can be marked on the map. The foundation is also supported by Agency of Natural Resources and Energy to promote cooperation activities with oil producing countries. 1 fig., 1 tab.

  14. On practicality of a hybrid car with solar cells; Taiyo denchi wo tosaishita hybrid car no jitsuyosei ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, K.; Nagayoshi, H.; Kamisako, K. [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1997-11-25

    The paper stated a development of a hybrid car which is a parallel type with gasoline engine and electric motor as driving source (connecting each according to the situation) and is also equipped with solar cells. Specifications are gasoline engine of 1200cc, induction motor of 5.5kW, lead battery of 288V and 7.2kWh, monocrystal silicon solar cells of 180W maximum output, and body weight of 1100kg. The rear wheel is driven by electric motor, and the front wheel by gasoline engine. The car is loaded with battery charge use solar cells on hood and roof. To enhance cleaning degree, 1.6kW solar cells are installed as an installed power system and used for battery charge. Even by an electric motor with output less than that of the usual electric car, harmful exhaust gas emitted in start-up can be controlled. This is because the electric motor can be used in accelerating. It was confirmed that the power required for it could be supplied by solar cells installed on the car. The hybrid car is practically useful for prevention of local air pollution. 5 refs., 4 figs., 2 tabs.

  15. Remote reference processing in MT survey using GPS clock; MT ho ni okeru GPS wo mochiita jikoku doki system

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, K.; Inoue, J.; Takasugi, S. [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan); Kosuge, S. [DRICO Co. Ltd., Tokyo (Japan)

    1996-05-01

    A report is given about the application of a synchronizing system using clock signals from GPS satellites to a remote reference method which is a technique to reject noise from the MT method. This system uses the C/A code out of the L1 band waves from NAVSTAR/GPS satellites. The new system was operated in MT method-using investigations conducted at China Peninsula, Aichi Prefecture, and Izu Peninsula, Shizuoka Prefecture, with the reference points placed several 100km away in Iwate Prefecture on both occasions. It was found as the result that it is basically possible to catch signals from the GPS at any place, that the signals are accurate enough to be applied to time synchronization for the MT method, and that the signals assure a far remote reference method with a separation of several 100km between the sites involved. The referencing process at high frequencies whose feasibility had been doubted proved a success when highly correlated signals were exchanged between two stations over a distance of several 100km. 5 refs., 9 figs.

  16. Hydrothermal deposition and photochromic performances of three kinds of hierarchical structure arrays of WO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Defang; Shen, Yi, E-mail: sysy7373@163.com; Ouyang, Yali; Li, Zhen

    2012-10-01

    Three kinds of tungsten oxide (WO{sub 3}) thin films have been fabricated by a simple hydrothermal deposition method. Scanning electron microscopy images of the products revealed that the capping agents did impact the microstructure of WO{sub 3} films. Films prepared without capping agents were ordered nanorod arrays, while the ones obtained with ethanol and oxalic acid revealed peeled-orange-like and cauliflower-like hierarchical structure arrays, respectively. Both of the two hierarchical structures were composed of much thinner nanorods compared with the one obtained without capping agents. All the WO{sub 3} films exhibited good photochromic properties and the two with inducers performed even better, which could be due to the changes in the microstructure that increased the amount of photogenerated electron-hole pairs and the proton diffusion rates. - Highlights: Black-Right-Pointing-Pointer Ordered WO{sub 3} nanorod arrays were prepared by hydrothermal deposition process. Black-Right-Pointing-Pointer Two hierarchical WO{sub 3} structure arrays were obtained with ethanol and oxalic acid. Black-Right-Pointing-Pointer Mechanism for the improved photochromic performances of WO{sub 3} films is proposed.

  17. CdWO{sub 4}-on-MEH-PPV:PS as a candidate for real-time dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.M. [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil); Novais, S.M.V.; Silva, E.S.S. [Group of Advanced Ceramic Materials, UFS, 49100-000 (Brazil); Schimitberger, T. [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil); Macedo, Z.S. [Group of Advanced Ceramic Materials, UFS, 49100-000 (Brazil); Bianchi, R.F., E-mail: bianchi@iceb.ufop.br [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil)

    2012-10-15

    We report on the investigations about the modification of optical properties induced by X-rays onto film detectors of cadmium tungstate (CdWO{sub 4}), poly[2-methoxy-5(2 Prime -ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) and polystyrene (PS) This device takes advantage of reduction of spectral overlap between the radioluminescence (RL) of CdWO{sub 4} and the absorption of MEH-PPV as it is exposed to radiation, forming the basis of a new dosimeter that is capable of converting the orange-red radioluminescence of PS:MEH-PPV:CdWO{sub 4} into green. We propose an explanation of the optical processes occurring in MEH-PPV:CdWO{sub 4} in terms of the radiation hardness of CdWO{sub 4} combined to the RL-induced degradation of MEH-PPV. Highlights: Black-Right-Pointing-Pointer Thin composite film dosimeters using a combination of a scintillator crystal and a light-emitting polymer. Black-Right-Pointing-Pointer A X-ray dose detector based on MEH-PPV/CdWO{sub 4} materials which are rarely seen together. Black-Right-Pointing-Pointer A new smart, disposable and easy-to-read organic-inorganic radiation detector.

  18. Hydrothermal synthesis of a novel BiErWO{sub 6} photocatalyst with wide spectral responsive property

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhijie, E-mail: zjzhang@sit.edu.cn [Department of Materials Science and Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Wang, Wenzhong [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Zhou, Yu [Department of Materials Science and Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China)

    2014-11-15

    Highlights: • A novel BiErWO{sub 6} photocatalyst was synthesized by a hydrothermal method. • The BiErWO{sub 6} showed good photocatalytic performance under simulated solar light. • The BiErWO{sub 6} also exhibited high photo-activity under a green LED irradiation. - Abstract: To overcome the drawback of low solar energy utilization rate brought by general photocatalysts, a novel BiErWO{sub 6} photocatalyst with wide spectral responsive property was designed and synthesized by a hydrothermal method. The effects of hydrothermal temperature on the phase structure and the photocatalytic activities of the products were investigated. Due to the wide spectral absorption range, the as-prepared BiErWO{sub 6} photocatalyst showed good photocatalytic performance in degradation of rhodamine B (RhB) under simulated solar light. Moreover, the BiErWO{sub 6} photocatalyst also exhibited high photocatalytic activity under a green LED (λ = 520 nm) irradiation. This work provided a new concept for rational design and development of high-performance photocatalysts.

  19. Graphitic g-C{sub 3}N{sub 4}-WO{sub 3} Composite: Synthesis and Photocatalytic Properties

    Energy Technology Data Exchange (ETDEWEB)

    Doan, An Tran; Thi, Xuan Dieu Nguyen; Nguyen, Phi Hung; Thi, Viet Nga Nguyen; Vo, Vien [Quy Nhon Univ., Quy Nhon (Viet Nam); Kim, Sung Jin [Ewha Womans Univ., Seoul (Korea, Republic of)

    2014-06-15

    Graphitic g-C{sub 3}N{sub 4}-WO{sub 3} composite was synthesized simply by decomposing melamine in the presence of WO{sub 3} at 500 .deg. C. The obtained material was characterized by XRD, SEM, IR and XPS. The results showed that the as-prepared composite exhibits orthorhombic WO{sub 3} phase coated by g-C{sub 3}N{sub 4} and the g-C{sub 3}N{sub 4} decomposed completely with N-doped WO{sub 3} remaining at elevated calcination temperatures. The photocatalytic activity of the composite was evaluated by the photodegradation of methylene blue under visible light. An enhancement in photocatalytic activity for the graphitic g-C{sub 3}N{sub 4}-WO{sub 3} composite compared to the conventional nitrogen-doped WO{sub 3} was observed, which can be attributed to the presence of g-C{sub 3}N{sub 4} in the material.

  20. Nanospherical composite of WO3 wrapped NaTaO3: Improved photodegradation of tetracycline under visible light irradiation

    Science.gov (United States)

    Qu, Lingnan; Lang, Junyu; Wang, Shuwei; Chai, Zhanli; Su, Yiguo; Wang, Xiaojing

    2016-12-01

    In this paper, WO3-wrapped NaTaO3 nanospheres photocatalysts with different W/Ta molar ratios were successfully prepared via a facile hydrothermal method. The samples were characterized by X-ray diffraction, transmission and scan electron microscopy, X-ray photoelectron spectroscopy, FT-IR spectrum, UV-vis diffuse reflectance spectroscopy, and Barrett-Emmett-Teller technique. The photocatalytic activities for degrading tetracycline hydrochloride under visible light irradiation were examined. The results indicated that the as-prepared NaTaO3@WO3 photocatalysts showed the obvious enhancement in the tetracycline hydrochloride degradation ratio, compared with the pure NaTaO3 and WO3 under visible light irradiation. The optimum percentage of NaTaO3@WO3 composites with a 60.88% degradation rate was W:Ta = 0.3:1 in mole, which was mainly attributed to the effective separation of the photo-generated electron and hole as well as the expanding of the absorption edge to the visible region due to the spherical heterojunction by wrapping WO3 on the surface of NaTaO3. The radicals trapping experiments demonstrated that there were multiple active species during the degrading process of TC. The possible mechanism of tetracycline hydrochloride degradation by NaTaO3@WO3 composite was also proposed.

  1. Atomic layer deposition of diisopropylaminosilane on WO3(001) and W(110): a density functional theory study.

    Science.gov (United States)

    Lee, Kyungtae; Lee, Woojin; Lee, Hyo Sug; Shin, Jaikwang; Park, Jieun; Lee, Seongsuk; Choi, Samjong; Kim, Sueryeon; Kim, Jinseong; Shim, Youngseon

    2016-10-26

    The decomposition reactions of the Si precursor, diisopropylaminosilane (DIPAS), on W(110) and hydroxylated WO3(001) surfaces are investigated to elucidate the initial reaction mechanism of the atomic layer deposition (ALD) process using density functional theory (DFT) calculations combined with ab initio molecular dynamics (AIMD) simulations. The decomposition reaction of DIPAS on WO3(001) consists of two steps: Si-N dissociative chemisorption and decomposition of SiH3*. It is found that the Si-N bond cleavage of DIPAS is facile on WO3(001) due to hydrogen bonding between the surface OH group and the N atom of DIPAS. The rate-determining step of DIPAS decomposition on WO3(001) is found to be the Si-H dissociation reaction of the SiH3* reaction intermediate which has an activation barrier of 1.19 eV. On the contrary, sequential Si-H dissociation reactions first occur on W(110) and then the Si-N dissociation reaction of the C5H7NSi* reaction intermediate is found to be the rate-determining step, which has an activation barrier of 1.06 eV. As a result, the final products in the DIPAS decomposition reaction on WO3(001) are Si* and SiH*, whereas Si* atoms remain with carbon impurities on W(110), which imply that the hydroxylated WO3 surface is more efficient for the ALD process.

  2. Facile synthesis of 2-D Cu doped WO3 nanoplates with structural, optical and differential anti cancer characteristics

    Science.gov (United States)

    Mehmood, Faisal; Iqbal, Javed; Gul, Asma; Ahmed, Waqqar; Ismail, M.

    2017-04-01

    Simple chemical co-precipitation method has been employed to synthesize two dimensional copper (Cu) doped tungsten oxide (WO3) nanoplates. A numbers of characterization techniques have been used to investigate their structural, optical and biocompatible anti cancer properties. The XRD results have confirmed the monoclinic crystal structure of WO3 nanoplates, and also successful doping of Cu ions into the WO3 crystal lattice. The presence of functional groups and chemical bonding have been verified through FTIR and Raman spectroscopy. The SEM images demonstrate that both undoped and Cu doped WO3 samples have squares plate like morphology. The EDX spectra confirm the presence of Cu, W and O ions. Diffuse reflectance spectroscopy (DRS) analysis has revealed a substantial red-shift in the absorption edge and a decrease in the band gap energy of nanoplates with Cu doping. Photoluminescence spectroscopy has been used to study the presence of defects like oxygen vacancies. Furthermore, the differential cytotoxic properties of Cu doped WO3 samples have been evaluated against human breast (MCF-7) and liver (Hep-2) cancer cells with ectocervical epithelial (HECE) healthy cells. The present findings confirm that the Cu doped WO3 nanoplates can be used as an efficient biocompatible anti cancer agent.

  3. Photocatalytic activity of Pt-modified Bi{sub 2}WO{sub 6} nanoporous wall under sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ya-Nan; Lu, Shi-Yu; Bao, Shu-Juan, E-mail: baoshj@swu.edu.cn [Southwest University, Faculty of Material & Energy, Institute for Clean Energy & Advanced Materials (China)

    2015-07-15

    In this work, Bi{sub 2}WO{sub 6} nanoporous wall was synthesized by using Bi{sub 2}O{sub 3} as template and Bi source. Pt nanoparticles whose average size is about 8 nm were further immobilized on the Bi{sub 2}WO{sub 6} nanoporous wall via a simple chemical reduction process. Their photocatalytic activity and the effect of Pt modification were studied by analyzing the degradation of an organic dye, rhodamine 6G (Rh6G), under simulated sunlight. It was found that the photocatalytic ability of Bi{sub 2}WO{sub 6} nanoporous wall was enhanced by introducing Pt nanoparticles. Bare Bi{sub 2}WO{sub 6} shows a degradation efficiency of 78 % after 1 h, while the degradation efficiency of 5 wt% Pt-modified Bi{sub 2}WO{sub 6} was 99 %, and on further increasing the Pt content in the as-prepared Pt-modified Bi{sub 2}WO{sub 6} catalysts, their photocatalytic ability will decrease. The optimal catalyst could be reused without any decrease for five cycles, which may due to Pt be able to help trap the conduction band electrons in the absence of Rh6G. A possible photocatalytic mechanism was proposed and further proved by transient photocurrent response experiment.

  4. Enhanced photocatalytic degradation of methyl orange by CdS quantum dots sensitized platelike WO3 photoelectrodes

    Institute of Scientific and Technical Information of China (English)

    文瑾; 刘灿军; 杜勇; 胡传跃; 田修营

    2015-01-01

    CdS quantum dots sensitized platelike WO3 photoelectrodes were successfully synthesized by a facile hydrothermal method and a modified chemical bath deposition (CBD) technique. To further improve the stability of the photoelectrodes in alkaline environment, the platelike WO3 films were treated with TiCl4 to form a nano-TiO2 buffer layer on the WO3 plate surface before loading CdS QDs. The resulting electrodes were characterized by using XRD, SEM, HR-TEM and UV-vis spectrum. The photocatalytic activity of the resulting electrodes was investigated by degradation of methyl orange (MO) in aqueous solution. The photoelectrochemical (PEC) property of the resulting electrodes was also characterized by the linear sweep voltammetry. The results of both the degradation of MO and photocurrent tests indicated that the as-prepared CdS QDs sensitized WO3 platelike photoelectrodes exhibit a significant improvement in photocatalytic degradation and PEC activity under visible light irradiation, compared with unsupported CdS QDs electrodes. Significantly, coating the WO3 plates with nano-TiO2 obviously facilitate the charge separation and retards the charge-pair recombination, and results in a highest activity for QDs CdS/TiO2/WO3photoelectrodes.

  5. WO3 Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates.

    Science.gov (United States)

    Choi, Seon-Jin; Kim, Sang-Joon; Cho, Hee-Jin; Jang, Ji-Soo; Lin, Yi-Min; Tuller, Harry L; Rutledge, Gregory C; Kim, Il-Doo

    2016-02-17

    A novel catalyst functionalization method, based on protein-encapsulated metallic nanoparticles (NPs) and their self-assembly on polystyrene (PS) colloid templates, is used to form catalyst-loaded porous WO3 nanofibers (NFs). The metallic NPs, composed of Au, Pd, or Pt, are encapsulated within a protein cage, i.e., apoferritin, to form unagglomerated monodispersed particles with diameters of less than 5 nm. The catalytic NPs maintain their nanoscale size, even following high-temperature heat-treatment during synthesis, which is attributed to the discrete self-assembly of NPs on PS colloid templates. In addition, the PS templates generate open pores on the electrospun WO3 NFs, facilitating gas molecule transport into the sensing layers and promoting active surface reactions. As a result, the Au and Pd NP-loaded porous WO3 NFs show superior sensitivity toward hydrogen sulfide, as evidenced by responses (R(air)/R(gas)) of 11.1 and 43.5 at 350 °C, respectively. These responses represent 1.8- and 7.1-fold improvements compared to that of dense WO3 NFs (R(air)/R(gas) = 6.1). Moreover, Pt NP-loaded porous WO3 NFs exhibit high acetone sensitivity with response of 28.9. These results demonstrate a novel catalyst loading method, in which small NPs are well-dispersed within the pores of WO3 NFs, that is applicable to high sensitivity breath sensors.

  6. Synthesis of bismuth tungstate (Bi{sub 2}WO{sub 6}) nanoflakes and their field emission investigation

    Energy Technology Data Exchange (ETDEWEB)

    Kolhe, P. S.; Sonawane, K. M. [Department of Physics, Fergusson College, Pune 411 004 (India); Bankar, P. K.; Gavhane, D. S.; More, M. A., E-mail: mam@physics.unipune.ac.in [Center for Advanced Studies in materials Science and Condensed Matter Physics, Department of Physics, Savitribai Phule Pune University, Pune-411 00.7 (India); Maiti, N. [Laser & Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2016-05-23

    The nanoflakes of Bismuth Tungstate (Bi{sub 2}WO{sub 6}) were successfully synthesized by a one-step facile hydrothermal route without using any templates or surfactants and field emission investigations of the Bi{sub 2}WO{sub 6} nanoflakes emitter are reported. Structural and morphological analysis of as-synthesized Bi{sub 2}WO{sub 6} nanoflakes has been carried out using X-ray diffraction (XRD) and scanning electron microscope (SEM). Moreover, the field emission characteristics of the Bi{sub 2}WO{sub 6} nanoflakes are found to be superior to the other semiconductor emitters. The synthesized Bi{sub 2}WO{sub 6} nanoflakes emitter delivers current density of ~222.35 μA/cm{sup 2} at an applied electric field of ~7.2 V/μm. The emission current stability investigated at pre-set value of ~2 μA is observed to be fairly good. These observed results demonstrate potential candidate of the Bi{sub 2}WO{sub 6} cathode as an electron source for practical applications in vacuum microelectronic device.

  7. 纳米WO_3/玻璃薄膜光催化性能研究%Photocatalysis Performance of Nano-WO_3/Glass Thin Film

    Institute of Scientific and Technical Information of China (English)

    吴永健; 张果龙

    2011-01-01

    以溶胶-凝胶法制备纳米WO3/玻璃薄膜,并用UV-Vis法,IR法和XRD方法进行了表征。以10 mg/L罗丹明B为降解对象,考察其光催化性能。结果表明:经500℃灼烧2 h以上制备的厚度为278 nm的两层涂膜,在pH=3.0、鼓入空气、光强为1.81×1016光子/s等条件下薄膜具有最佳光催化活性,对罗丹明B的光催化降解效率在60 min内达到90%以上。%The nano-tungsten oxide(WO3)/glass thin film prepared by sol-gel method was investigated.The structure and photocatalytic behavior of the tungsten oxide(WO3) thin films was assessed by UV-Vis,XRD and IR.10 mg/L Rhodamine B solution was degradated on the thin film as an object of investigation.The removal ratio of Rhodamine B can reach 90% in 60 min under the condition that the media acidity was pH=3.0,air was plumped to the reactor through a gas pipe,and light intensity of 1.81×1016 photon/s.The two coating layer thin films were calcined at 500 ℃ for 2 h.

  8. Synthesis of TiO2/WO3 nanoparticles via sonochemical approach for the photocatalytic degradation of methylene blue under visible light illumination.

    Science.gov (United States)

    Anandan, Sambandam; Sivasankar, Thirugnanasambandam; Lana-Villarreal, Teresa

    2014-11-01

    Through an ultrasound assisted method, TiO2/WO3 nanoparticles were synthesized at room temperature. The XRD pattern of as-prepared TiO2/WO3 nanoparticles matches well with that of pure monoclinic WO3 and rutile TiO2 nanoparticles. TEM images show that the prepared TiO2/WO3 nanoparticles consist of mixed square and hexagonal shape particles about 8-12nm in diameter. The photocatalytic activity of TiO2/WO3 nanoparticles was tested for the degradation of a wastewater containing methylene blue (MB) under visible light illumination. The TiO2/WO3 nanoparticles exhibits a higher degradation rate constant (6.72×10(-4)s(-1)) than bare TiO2 nanoparticles (1.72×10(-4)s(-1)) under similar experimental conditions.

  9. A significant cathodic shift in the onset potential and enhanced photoelectrochemical water splitting using Au nanoparticles decorated WO3 nanorod array.

    Science.gov (United States)

    Xu, Fang; Yao, Yanwen; Bai, Dandan; Xu, Ruishu; Mei, Jingjing; Wu, Dapeng; Gao, Zhiyong; Jiang, Kai

    2015-11-15

    Au nanoparticles decorated WO3 nanorod array was prepared and applied for solar water oxidation. Scanning electron microscopy and transmission electron microscop images showed that Au distributed on the surface of WO3 nanorod array. The surface plasmon resonance effect of Au nanoparticles contributed to the enhancement of photoelectrochemical performance of Au-WO3 photoanode, such as enhanced photocurrent density of 1.17mA/cm(2) at 1.0V vs Ag/AgCl, a cathodic shift of onset of ∼0.2V and higher stability. UV-vis absorption, electrochemical impedance and Mott-Schottky measurements proved that Au-WO3 photoanode has enhanced light absorption, lower transfer resistance, increased photogenerated carriers density and higher hole injection yield. Therefore, Au-WO3 photoanode exhibited higher photoelectrochemical performance than WO3 photoanode.

  10. HT-solution growth and characterisation of InxNaxMn1-2xWO4 (0

    Science.gov (United States)

    Gattermann, U.; Park, S.-H.; Paulmann, C.; Benka, G.; Pfleiderer, C.

    2016-12-01

    A new solid solution system, InxNaxMn1-2xWO4 (0Specific heat and magnetisation measurements showed a paramagnetic dilution effect from (In3+/Na+)-doping while lowering the transition temperature for the multiferroic phase AF2 of InxNaxMn1-2xWO4 with respect to the prototype MnWO4.

  11. Synthesis of multiple-shell WO3 hollow spheres by a binary carbonaceous template route and their applications in visible-light photocatalysis.

    Science.gov (United States)

    Xi, Guangcheng; Yan, Yan; Ma, Qiang; Li, Junfang; Yang, Haifeng; Lu, Xiaojing; Wang, Chao

    2012-10-29

    Hollow go lightly: well-defined multiple-shell WO(3) hollow spheres were synthesized by a facile binary carbonaceous spheres template route. Compared with single-shell WO(3) hollow spheres, the unusual porous multiple-shell structure of the WO(3) hollow spheres proves to greatly enhance photocatalytic activity toward degradation of organic pollutants under visible-light irradiation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Defect engineering of two-dimensional WO3 nanosheets for enhanced electrochromism and photoeletrochemical performance

    Science.gov (United States)

    Zhou, Xiaofang; Zheng, Xiaoli; Yan, Bo; Xu, Tao; Xu, Qun

    2017-04-01

    The capability of introduction of oxygen vacancies in a controlled way has emerged as the heart of modern transition metal oxide semiconductor chemistry. As chemical defects, the oxygen vacancies have been proposed as electron donors, which are prone to increase carrier density and promote charge carrier separation. Herein, we have successfully prepared 2D WO3 ultrathin nanosheets with abundant surface oxygen vacancies by a combination of facile solvothermal reaction and hydrogenation method. The resultant hydrogenated WO3 ultrathin nanosheets exhibit remarkable electrochromism and photocatalytic performances compared with the non-hydrogenated samples, mainly due to their increased oxygen vacancies, narrowed band gap coupled with fast charge transfer and enhanced adsorption of visible light.

  13. AC conductivity and dielectric properties of bulk tungsten trioxide (WO{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    El-Nahass, M.M. [Department of Physics, Faculty of Education, Ain Shams University, Roxy 11757, Cairo (Egypt); Ali, H.A.M., E-mail: hend2061@yahoo.com [Department of Physics, Faculty of Education, Ain Shams University, Roxy 11757, Cairo (Egypt); Saadeldin, M.; Zaghllol, M. [Physics Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)

    2012-11-15

    AC conductivity and dielectric properties of tungsten trioxide (WO{sub 3}) in a pellet form were studied in the frequency range from 42 Hz to 5 MHz with a variation of temperature in the range from 303 K to 463 K. AC conductivity, {sigma}{sub ac}({omega}) was found to be a function of {omega}{sup s} where {omega} is the angular frequency and s is the frequency exponent. The values of s were found to be less than unity and decrease with increasing temperature, which supports the correlated barrier hopping mechanism (CBH) as the dominant mechanism for the conduction in WO{sub 3}. The dielectric constant ({epsilon} Prime ) and dielectric loss ({epsilon} Double-Prime ) were measured. The Cole-Cole diagram determined complex impedance for different temperatures.

  14. Investigation of multiferroic properties in MnWO{sub 4} by SHG-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Maringer, Michael; Meier, Dennis; Lottermoser, Thomas; Yuan, Gouliang; Fiebig, Manfred [HISKP, Universitaet Bonn (Germany); Becker, Petra; Bohaty, Ladislav [Institut fuer Kristallographie, Universitaet zu Koeln (Germany)

    2008-07-01

    Magnetoelectric multiferroics, i.e. compounds displaying magnetic and ferroelectric order in the same phase, attract considerable attention from the point of view of potential device application as well as fundamental physics. In the so-called spin-spiral compounds the interaction is particularly pronounced. Here we introduce optical second harmonic generation (SHG) as a powerful tool for the study of magnetic and eletronic properties and their magnetoelectric interaction in spin-spiral compounds, taking MnWO{sub 4} as an example. SHG gives detailed information about the symmetry of crystalline phases and about symmetry changes caused by phase transitions. In particular, in MnWO{sub 4} the (anti)ferromagnetic incommensurate phase and the magnetically induced ferroelectric, state are investigated. Although the magnetically induced spontaneous polarization is about four orders of magnitude weaker than in a conventional ferroelectric, a pronounced SHG signal is obtained.

  15. Recognizing Amino Acid Chirality with Surface-Imprinted Polymers Prepared in W/O Emulsions

    Directory of Open Access Journals (Sweden)

    Min Jae Shin

    2013-01-01

    Full Text Available A molecularly imprinted polymer was prepared by a surface molecular imprinting technique in water-in-oil (W/O emulsion. In this technique, the solid polymer, which is molecularly imprinted at the internal cavity surface, is prepared by polymerizing W/O emulsions consisting of a water-soluble imprinted molecule, a functional host molecule, an emulsion stabilizer, and a crosslinking agent. Dioleoyl phosphate was used as an emulsion stabilizer, and this compound also acted as a monomer and a host functional group in the imprinted cavity. Divinylbenzene was used as a crosslinker. Tryptophan methyl ester and phenylalanine methyl ester were used as the target template materials. These imprinted polymers exhibited enantiomeric selectivity in absorption experiments, and the maximum separation factor was 1.58. The enantiomeric selectivity with tryptophan methyl ester was higher than that with phenylalanine methyl ester.

  16. Effects of high pressure on the optical absorption spectrum of scintillating PbWO4 crystals

    OpenAIRE

    Errandonea, D.; Martinez-Garcia, D.; Lacomba-Perales, R.; Ruiz-Fuertes, J.; Segura, A

    2006-01-01

    The pressure behavior of the absorption edge of PbWO4 was studied up to 15.3 GPa. It red-shifts at -71 meV/GPa below 6.1 GPa, but at 6.3 GPa the band-gap collapses from 3.5 eV to 2.75 eV. From 6.3 GPa to 11.1 GPa, the absorption edge moves with a pressure coefficient of -98 meV/GPa, undergoing additional changes at 12.2 GPa. The results are discussed in terms of the electronic structure of PbWO4 which attribute the behavior of the band-gap to changes in the local atomic structure. The changes...

  17. Systematical investigation on the luminescence enhancement of PbWO4 crystals by doping and annealing

    CERN Document Server

    Huang, Yanlin

    2004-01-01

    PbWO4 crystal has been chosen for a scintillating detector at the Large Hadron Collider (LHC) in CERN due to its high density, short radiation length and fast decay time. Extensive investigations have been done around the world to improve the scintillation performance by annealing treatment and aliavalent ion doping in the crystals. The works in this report are focused on the enhancement of light yield in PbWO4 crystals by doping and annealing, and excellent scintillation performance still are kept for this material. The doping ions in the crystal include monovalent ions, trivalent ions and co-doping between different aliavalent ions. Many results were first report in the material. Meanwhile, the annealing mechanism and aliavalent ion doping mechanism from viewpoint of microstructure were also discussed. Besides, these results reveal also that PWO might have potential use in the PET material, even in the optoelectronic application.

  18. A New Hydrogen Sensor Based on SNS Fiber Interferometer with Pd/WO3 Coating

    Directory of Open Access Journals (Sweden)

    Jinxin Shao

    2017-09-01

    Full Text Available This paper presents a new hydrogen sensor based on a single mode–no core–single mode (SNS fiber interferometer structure. The surface of the no core fiber (NCF was coated by Pd/WO3 film to detect the variation of hydrogen concentration. If the hydrogen concentration changes, the refractive index of the Pd/WO3 film as well as the boundary condition for light propagating in the NCF will all be changed, which will then cause a shift into the resonant wavelength of interferometer. Therefore, the hydrogen concentration can be deduced by measuring the shift of the resonant wavelength. Experimental results demonstrated that this proposed sensor had a high detection sensitivity of 1.26857 nm/%, with good linearity and high accuracy (maximum 0.0055% hydrogen volume error. Besides, it also possessed the advantages of simple structure, low cost, good stability, and repeatability.

  19. Graphene Q-switched Tm:KY(WO4)2 waveguide laser

    Science.gov (United States)

    Kifle, E.; Mateos, X.; Loiko, P.; Yumashev, K.; Yasukevich, A.; Petrov, V.; Griebner, U.; Aguiló, M.; Díaz, F.

    2017-04-01

    We report on the first Tm3+-doped double tungstate waveguide laser passively Q-switched by a graphene saturable absorber using a 12.4 µm-thick 3 at.% Tm:KY0.58Gd0.22Lu0.17(WO4)2 epitaxial layer grown on a (0 1 0)-oriented pure KY(WO4)2 substrate. This laser generated 5.8 nJ/195 ns pulses at 1831.8 nm corresponding to a pulse repetition frequency of 1.13 MHz. These are the shortest pulses achieved in passively Q-switched Tm waveguide lasers. The laser slope efficiency was 9% and the Q-switching conversion efficiency reached 45%. Graphene is promising for the generation of ns pulses at ~2 µm in Tm3+-doped double tungstate waveguide lasers operating in the MHz-range.

  20. Solvothermal synthesis, characterization and photocatalytic performance of Zn-rich ZnWO4 nanocrystals

    Science.gov (United States)

    Wang, Yunjian; Liping, Li; Li, Guangshe

    2017-01-01

    Present work focuses on the surface composition disorder, its origin and relevance to photoluminescent and photocatalytic properties of ZnWO4 nanocrystals. ZnWO4 nanoparticles were synthesized under solvothermal conditions, in which formic acid was employed for both the nonstoichiometry and kinetic size control. Nonstoichiometry ranging from 1.05 to 1.18 was originated from the surface Zn-rich disorder layer, as reflected by an excess of cation Zn2+ in the X-ray photoelectron spectroscopy and a new Raman vibration mode at about 930 cm-1 and HR-TEM images. Surface Zn-rich disorder layer has shown a great impact on the structure and properties, including lattice expansion, band-gap narrowing, luminescence enhancement, as well as photocatalytic weakening effect. The investigation on surface composition disorder of multi-component oxides is helpful to deeply understand their formation process and further to find a new functionality optimizing approach.

  1. Synthesis and characterization of WO{sub 3} nanostructures prepared by an aged-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Huirache-Acuna, R., E-mail: rafael_huirache@yahoo.it [CFATA-UNAM, Boulevard Juriquilla 3001, Juriquilla Queretaro, 76230 (Mexico); Universidad La Salle Morelia, Av. Universidad 500, Mpio. Tarimbaro Mich., 58880 (Mexico); Paraguay-Delgado, F. [Centro de Investigacion en Materiales Avanzados, S.C. CIMAV, Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chih., 31109 (Mexico); Albiter, M.A.; Lara-Romero, J. [Facultad de Ingenieria Quimica, Universidad Michoacana de San Nicolas de Hidalgo, Morelia Mich., 58000 (Mexico); Martinez-Sanchez, R. [Centro de Investigacion en Materiales Avanzados, S.C. CIMAV, Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chih., 31109 (Mexico)

    2009-09-15

    Nanostructures of tungsten trioxide (WO{sub 3}) have been successfully synthesized by using an aged route at low temperature (60 deg. C) followed by a hydrothermal method at 200 deg. C for 48 h under well controlled conditions. The material was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Specific Surface Area (S{sub BET}) were measured by using the BET method. The lengths of the WO{sub 3} nanostructures obtained are between 30 and 200 nm and their diameters are from 20 to 70 nm. The growth direction of the tungsten oxide nanostructures was determined along [010] axis with an inter-planar distance of 0.38 nm.

  2. Pulse-shape discrimination with PbWO$_4$ crystal scintillators

    CERN Document Server

    Bardelli, L; Bizzeti, P G; Danevich, F A; Fazzini, T F; Kobychev, V V; Krutyak, N; Maurenzig, P R; Mokina, V M; Nagorny, S S; Pashkovskii, M; Poda, D V; Tretyak, V I; Yurchenko, S S

    2007-01-01

    The light output, $\\alpha/\\beta$ ratio, and pulse shape have been investigated at $-25^\\circ$ C with PbWO$_4$ crystal scintillators undoped, and doped by F, Eu, Mo, Gd and S. The fast $0.01-0.06 \\mu$s and middle $0.1-0.5 \\mu$s components of scintillation decay were observed for all the samples. Slow components of scintillation signal with the decay times $1-3 \\mu$s and $13-28 \\mu$s with the total intensity up to $\\approx50%$ have been recognized for several samples doped by Molybdenum. We found some indications of a pulse-shape discrimination between $\\alpha$ particles and $\\gamma$ quanta with PbWO$_4$ (Mo doped) crystal scintillators.

  3. Pulse-shape discrimination with PbWO{sub 4} crystal scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Bardelli, L.; Bini, M.; Bizzeti, P.G. [Dipartimento di Fisica, Universita di Firenze and INFN, 50019 Florence (Italy); Danevich, F.A. [Institute for Nuclear Research, Prospect Nauki 47, MSP 03680 Kyiv (Ukraine)], E-mail: danevich@kinr.kiev.ua; Fazzini, T.F. [Dipartimento di Fisica, Universita di Firenze and INFN, 50019 Florence (Italy); Krutyak, N. [Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Vorob' evy Gory, 119992 Moscow (Russian Federation); Kobychev, V.V. [Institute for Nuclear Research, Prospect Nauki 47, MSP 03680 Kyiv (Ukraine); Maurenzig, P.R. [Dipartimento di Fisica, Universita di Firenze and INFN, 50019 Florence (Italy); Mokina, V.M.; Nagorny, S.S. [Institute for Nuclear Research, Prospect Nauki 47, MSP 03680 Kyiv (Ukraine); Pashkovskii, M. [Department of Semiconductors Physics, Ivan Franko National University, UA-79005 Lviv (Ukraine); Poda, D.V.; Tretyak, V.I.; Yurchenko, S.S. [Institute for Nuclear Research, Prospect Nauki 47, MSP 03680 Kyiv (Ukraine)

    2008-01-01

    Light output, {alpha}/{beta} ratio, and pulse shape have been investigated at -25 deg. C with PbWO{sub 4} crystal scintillators undoped, and doped by F, Eu, Mo, Gd and S. The fast 0.01-0.06{mu}s and middle 0.1-0.5{mu}s components of scintillation decay were observed for all the samples. Slow components of scintillation signal with decay times 1-3 and 13-28{mu}s with total intensity up to {approx}50% have been recognized for several samples doped by Molybdenum. We found some indications of a pulse-shape discrimination between {alpha} particles and {gamma} quanta with PbWO{sub 4} (Mo doped) crystal scintillators.

  4. Precipitation Synthesis, Characterization, Morphological Control, and Photocatalyst Application of ZnWO4 Nanoparticles

    Science.gov (United States)

    Hosseinpour-Mashkani, S. Mostafa; Maddahfar, Mahnaz; Sobhani-Nasab, Ali

    2016-07-01

    Zinc tungstate nanoparticles have been successfully synthesized by a precipitation method in the presence of different polymeric surfactants. This study aimed to investigate the effect of different solvents and polymeric surfactants such as carboxymethyl cellulose, polyethylene glycol, and polyvinyl alcohol on the morphology, particle size, and crystal structure of the final product. The as-synthesized products were characterized by powder x-ray diffraction analysis, scanning electron microscopy, ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, transmission electron microscopy, and energy-dispersive x-ray spectroscopy techniques. Furthermore, the hysteresis loop of the zinc tungstate nanoparticles at room temperature revealed paramagnetic behavior. Photocatalysis results revealed that maximum methyl orange decolorization of 85% was achieved with ZnWO4 nanoparticles in 240 min under visible-light irradiation. The saturation magnetization, remanent magnetization, and coercivity of the ZnWO4 nanoparticles were 0.003 emu/g, 0.0005 emu/g, and 110 Oe, respectively.

  5. Propane oxidation on Pt-WO3/g -AL2O3 catalytic systems

    Directory of Open Access Journals (Sweden)

    Silva M.A.Pereira da

    2003-01-01

    Full Text Available The oxidation of propane on was studied with Pt-xWO3/Al2O3 catalysts was studied ,by varying the concentration of tungsten sublayer. Thermal analysis and XRD in situ showed that the enrichment of tungsten at the surface is associated with the formation of HxWO3 bronze. FTIR results with C3H8 and O2 indicated that the catalyst surface properties and the interaction between W and Pt were modified. These modified surface complexes prevented the formation of acetates and formate species. The addition of W increased the activity of Pt/Al2O3 towards in C3H8 oxidation. Tungsten was the main responsible for the stability of the bimetallic catalysts in the presence of water.

  6. Oxidative Desulfurization of Diesel Fuel with Hydrogen Peroxide Using Na2WO4 s Catalyst

    Institute of Scientific and Technical Information of China (English)

    Sun Xin; Long Jun; Xu Benjing; Xie Chaogang

    2009-01-01

    Oxidative desulfurization was performed on Na2WO4 catalyst in the presence of hydrogen peroxide and acetic acid under mild reaction conditions (atmospheric pressure and temperature range of 293-343 K). Different organic com-pounds including benzothiophene (BT), dibenzothiophene (DBT), 4, 6-dimethyl dibenzothiophene (4, 6-DMDBT) were used to investigate the reactivity of this catalyst, and the effect of various parameters, such as temperature, solvents and the amount of oxidant reagent used in oxidative desulfurization reaction, was also examined. The results showed that the Na2WO4-H2O2 system was very effective for oxidative desulfurization, and the oxidation of BT, DBT and 4, 6-DMDBT was influ-enced by different parameters.

  7. Hydrothermal synthesis of TiO2/WO3 compositions and their photocatalytic activity

    Science.gov (United States)

    Pyachin, Sergey A.; Karpovich, Natalia F.; Zaitsev, Alexey V.; Makarevich, Konstantin S.; Burkov, Alexander A.; Ustinov, Alexander Yu.

    2016-11-01

    Photocatalytic activity, optical properties, thermal stability, phase patterns and morphology of nano-size TiO2/WO3 compositions obtained from organic precursors through hydrothermal synthesis have been studied. It has been shown that doping of anatase nanoparticles with tungsten W+6 results in particle diameter reduction from 35 to 10 nm; decrease in width of the band gap from 3.15 eV to 2.91 eV and increase in temperature of phase transition of anatase to rutile up to 980oC. Catalytic activity of TiO2/WO3 (4 mol.%) composition under photochemical methylene blue (MB) oxidation by simulated solar light exceeds that of undoped anatase (obtained in the same way) 6-fold.

  8. Characterization of MnWO4 with flower-like clusters produced using spray pyrolysis

    Institute of Scientific and Technical Information of China (English)

    Somchai THONGTEM; Surangkana WANNAPOP; Titipun THONGTEM

    2009-01-01

    MnWO4 (huebnerite) with flower-like clusters of nano-plates was produced from the solutions containing MnCl2·4H2O and Na2WO4·2H2O by the 300℃ spray pyrolysis. The phase was detected by X-ray diffraction (XRD) and selected area electron diffraction (SAED), and is in accordance with the results characterized using energy dispersive X-ray (EDX) analysis. The flower-like clusters of nano-plates were characterized using scanning and transmission electron microscopes (SEM and TEM), and their parallel lattice planes using a high resolution transmission electron microscope (HRTEM). Vibration spectra of the huebnerite structured products were characterized using Raman and Fourier transform infrared (FTIR) spectrometers. Their photoluminescence (PL) emissions are in the same spectral region at 405-412 nm.

  9. The growth units and hydrothermal preparation of lead tungstate (PbWO4) crystallites

    Institute of Scientific and Technical Information of China (English)

    元如林; 施尔畏; 李汶军; 郑燕青; 吴南春; 仲维卓

    2000-01-01

    The crystal structure of lead tungstate (PbWO4) can be regarded as ordered combination of the tungsten oxide tetrahedrons (WO4) and lead ions (Pb2+). According to the growth unit model, the growth units of lead tungstate are the aggregations of the tungsten oxide tetrahedrons and lead cations with various geometry configurations. It is suggested that the favorable growth units of lead tungstate crystal are pyramidal, tetragonal prism and quadrangular units corresponding to geometric orientations of the simple forms of the crystal. Under low restricted growth conditions, the growth form of lead tungstate crystallites is the aggregation of the geometric configurations of these favorable growth units. The above conclusions are completely confirmed by the experiment on hydrothermal preparation of lead tungstate crystallites.

  10. Electronic Structures of PbWO4 Crystals Containing F-Type Colour Centres

    Institute of Scientific and Technical Information of China (English)

    YI Zhi-Jun; LIU Ting-Yu; ZHANG Qi-Ren; SUN Yuan-Yuan

    2005-01-01

    @@ Electronic structures of PbWO4 crystals containing F-type colour centres with the lattice structure optimized are studied within the framework of the fully relativistic selF-consistent Dirac-Slater theory, using a numerically discrete variational (DV-Xα) method. The calculated results show that F and F+ centres have donor energy levels in the forbidden bands. Their optical transition energies are 1.84 eV and 2.21 eV, respectively, which correspond to the 680nm and 550nm absorption bands. It is predicted that the 680nm and 550nm absorption banas originate from the F and F+ centres in PbWO4 crystals.

  11. The growth units and hydrothermal preparation of lead tungstate (PbWO4) crystallites

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The crystal structure of lead tungstate (PbWO4) can be regarded as ordered combination of the tungsten oxide tetrahedrons (WO4) and lead ions (Pb2+). According to the growth unit model, the growth units of lead tungstate are the aggregations of the tungsten oxide tetrahedrons and lead cations with various geometry configurations. It is suggested that the favorable growth units of lead tungstate crystal are pyramidal, tetragonal prism and quadrangular units corresponding to geometric orientations of the simple forms of the crystal. Under low restricted growth conditions, the growth form of lead tungstate crystallites is the aggregation of the geometric configurations of these favorable growth units. The above conclusions are completely confirmed by the experiment on hydrothermal preparation of lead tungstate crystallites.

  12. Preparation of CuCrO2-WO3 and its photocatalytic performance for hydrogen production%CuCrO2-WO3的制备及光催化产氢性能

    Institute of Scientific and Technical Information of China (English)

    王桂赟; 刘先平; 赵茜; 王延吉; 林瑞榕

    2014-01-01

    The principle of p-n type semiconductor composite photocatalysts is discussed as a strategy to develop efficient photocatalysts for water splitting. Composite of p-type and n-type semiconductor has an advantage in taking full use of each semiconductor’s function of oxidation and reduction, which could facilitate the photo-induced electron/hole pairs’ separation by the inner electric field, enhancing the photocatalytic efficiency of the system. CuCrO2 was synthesized by a novel combustion reaction method with glycerin as fuel, and WO3 was prepared by the tungsten acid decomposition method. The configurations CuCrO2-WO3 and Ru/(CuCrO2-WO3) were successfully prepared by mechanical grinding and heat-treatment. The prepared samples were characterized by using X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance (UV-vis DR), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of CuCrO2, WO3, CuCrO2-WO3 and Ru/(CuCrO2-WO3) were evaluated under xenon lamp irradiation. The factors including pH of grinding media and Ru loading were also investigated. When glycerin was used as the sacrificial reagent under xenon lamp irradiation, CuCrO2 or WO3 powders alone was not able to catalyze H2 generation from water splitting, while coupled photocatalysts of CuCrO2-WO3 displayed remarkable photocatalytic activity. The improvement of photocatalytic activity was attributed to the formation of p-n junctures at the interface of CuCrO2-WO3. When grinding media was at pH 8, dispersion of WO3 was particularly better, which contributed to more efficient compounding of the two powders and better activity of the composite as a consequence. Ru loading as cocatalyst also remarkably enhanced photocatalytic hydrogen production. The 0.5% (mass) Ru/(CuCrO2-WO3) exhibited better photocatalytic activity for splitting pure water into hydrogen under 300W xenon lamp irradiation, on which H2 production was about 10μmol for 3 h.%作

  13. Development of w/o microemulsion for transdermal delivery of iodide ions.

    Science.gov (United States)

    Lou, Hao; Qiu, Ni; Crill, Catherine; Helms, Richard; Almoazen, Hassan

    2013-03-01

    The objective of this study was to develop a water-in-oil (w/o) microemulsion which can be utilized as a transdermal delivery for iodide ions. Several w/o microemulsion formulations were prepared utilizing Span 20, ethanol, Capryol 90®, and water. The selected formulations had 5%, 10%, 15%, 20%, and a maximum of 23% w/w water content. Potassium iodide (KI) was incorporated in all formulations at 5% w/v. Physicochemical characterizations were conducted to evaluate the structure and stability. These studies included: mean droplet size, pH, viscosity, conductivity, and chemical stability tests. In vitro human skin permeation studies were conducted to evaluate the diffusion of the iodide ion through human skin. The w/o microemulsion formulations were stable and compatible with iodide ions with water content ranging from 5% to 23% w/w. The addition of KI influenced the physicochemical properties of microemulsion as compared to blank microemulsion formulations. In vitro human skin permeation studies indicated that selected formulations improved iodide ion diffusion significantly as compared to control (KI solution; P valueIodide ions were entrapped within the aqueous core of w/o microemulsion. Span 20, ethanol and Capryol 90 protected the iodide ions against oxidation and formed a stable microemulsion. It is worth to note that according to Hofmeister series, iodide ions tend to lower the interfacial tension between water and oil and consequently enhance overall stability. This work illustrates that microemulsion system can be utilized as a vehicle for the transdermal administration of iodide.

  14. Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter

    CERN Document Server

    Adzic, P; Andelin, D; Anicin, I; Antunovic, Z; Arcidiacono, R; Arenton, M W; Auffray, E; Argiro, S; Askew, A; Baccaro, S; Baffioni, S; Balazs, M; Bandurin, D; Barney, D; Barone, L M; Bartoloni, A; Baty, C; Beauceron, S; Bell, K W; Bernet, C; Besancon, M; Betev, B; Beuselinck, R; Biino, C; Blaha, J; Bloch, P; Borisevitch, A; Bornheim, A; Bourotte, J; Brown, R M; Buehler, M; Busson, P; Camanzi, B; Camporesi, T; Cartiglia, N; Cavallari, F; Cecilia, A; Chang, P; Chang, Y H; Charlot, C; Chen, E A; Chen, W T; Chen, Z; Chipaux, R; Choudhary, B C; Choudhury, R K; Cockerill, D J A; Conetti, S; Cooper, S; Cossutti, F; Cox, B; Cussans, D G; Dafinei, I; Da Silva Di Calafiori, D R; Daskalakis, G; David, A; Deiters, K; Dejardin, M; De Benedetti, A; Della Ricca, G; Del Re, D; Denegri, D; Depasse, P; Descamps, J; Diemoz, M; Di Marco, E; Dissertori, G; Dittmar, M; Djambazov, L; Djordjevic, M; Dobrzynski, L; Dolgopolov, A; Drndarevic, S; Drobychev, G; Dutta, D; Dzelalija, M; Elliott-Peisert, A; El Mamouni, H; Evangelou, I; Fabbro, B; Faure, J L; Fay, J; Fedorov, A; Ferri, F; Franci, D; Franzoni, G; Freudenreich, K; Funk, W; Ganjour, S; Gascon, S; Gataullin, M; Gentit, F X; Ghezzi, A; Givernaud, A; Gninenko, S; Go, A; Gobbo, B; Godinovic, N; Golubev, N; Govoni, P; Grant, N; Gras, P; Haguenauer, M; Hamel de Monchenault, G; Hansen, M; Haupt, J; Heath, H F; Heltsley, B; Hintz, W; Hirosky, R; Hobson, P R; Honma, A; Hou, G W S; Hsiung, Y; Huhtinen, M; Ille, B; Ingram, Q; Inyakin, A; Jarry, P; Jessop, C; Jovanovic, D; Kaadze, K; Kachanov, V; Kailas, S; Kataria, S K; Kennedy, B W; Kokkas, P; Kolberg, T; Korjik, M; Krasnikov, N; Krpic, D; Kubota, Y; Kuo, C M; Kyberd, P; Kyriakis, A; Lebeau, M; Lecomte, P; Lecoq, P; Ledovskoy, A; Lethuillier, M; Lin, S W; Lin, W; Litvine, V; Locci, E; Longo, E; Loukas, D; Luckey, P D; Lustermann, W; Ma, Y; Malberti, M; Malclès, J; Maletic, D; Manthos, N; Maravin, Y; Marchica, C; Marinelli, N; Markou, A; Markou, C; Marone, M; Matveev, V; Mavrommatis, C; Meridiani, P; Milenovic, P; Miné, P; Missevitch, O; Mohanty, A K; Moortgat, F; Musella, P; Musienko, Y; Nardulli, A; Nash, J; Nedelec, P; Negri, P; Newman, H B; Nikitenko, A; Nessi-Tedaldi, F; Obertino, M M; Organtini, G; Orimoto, T; Paganoni, M; Paganini, P; Palma, A; Pant, L; Papadakis, A; Papadakis, I; Papadopoulos, I; Paramatti, R; Parracho, P; Pastrone, N; Patterson, J R; Pauss, F; Peigneux, J-P; Petrakou, E; Phillips II, D G; Piroué, P; Ptochos, F; Puljak, I; Pullia, A; Punz, T; Puzovic, J; Ragazzi, S; Rahatlou, S; Rander, J; Razis, P A; Redaelli, N; Renker, D; Reucroft, S; Ribeiro, P; Rogan, C; Ronquest, M; Rosowsky, A; Rovelli, C; Rumerio, P; Rusack, R; Rusakov, S V; Ryan, M J; Sala, L; Salerno, R; Schneegans, M; Seez, C; Sharp, P; Shepherd-Themistocleous, C H; Shiu, J G; Shivpuri, R K; Shukla, P; Siamitros, C; Sillou, D; Silva, J; Silva, P; Singovsky, A; Sirois, Y; Sirunyan, A; Smith, V J; Stöckli, F; Swain, J; Tabarelli de Fatis, T; Takahashi, M; Tancini, V; Teller, O; Theofilatos, K; Thiebaux, C; Timciuc, V; Timlin, C; Titov, M; Topkar, A; Triantis, F A; Troshin, S; Tyurin, N; Ueno, K; Uzunian, A; Varela, J; Verrecchia, P; Veverka, J; Virdee, T; Wang, M; Wardrope, D; Weber, M; Weng, J; Williams, J H; Yang, Y; Yaselli, I; Yohay, R; Zabi, A; Zelepoukine, S; Zhang, J; Zhang, L Y; Zhu, K; Zhu, R Y

    2010-01-01

    Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered.

  15. Structural, microstructural and vibrational analyses of the monoclinic tungstate BiLuWO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Ait Ahsaine, H. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106 Cité Dakhla, Agadir (Morocco); Taoufyq, A. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106 Cité Dakhla, Agadir (Morocco); Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France); Patout, L. [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France); Ezahri, M.; Benlhachemi, A.; Bakiz, B. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106 Cité Dakhla, Agadir (Morocco); Villain, S.; Guinneton, F. [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France); Gavarri, J.-R., E-mail: gavarri.jr@univ-tln.fr [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France)

    2014-10-15

    The bismuth lutetium tungstate phase BiLuWO{sub 6} has been prepared using a solid state route with stoichiometric mixtures of oxide precursors. The obtained polycrystalline phase has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. In the first step, the crystal structure has been refined using Rietveld method: the crystal cell was resolved using monoclinic system (parameters a, b, c, β) with space group A2/m. SEM images showed the presence of large crystallites with a constant local nominal composition (BiLuW). TEM analyses showed that the actual local structure could be better represented by a superlattice (a, 2b, c, β) associated with space groups P2 or P2/m. The Raman spectroscopy showed the presence of vibrational bands similar to those observed in the compounds BiREWO{sub 6} with RE=Y, Gd, Nd. However, these vibrational bands were characterized by large full width at half maximum, probably resulting from the long range Bi/Lu disorder and local WO{sub 6} octahedron distortions in the structure. - Graphical abstract: The average structure of BiLuWO{sub 6} determined from X-ray diffraction data can be represented by A2/m space group. Experimental Electron Diffraction patterns along the [0vw] zone axes of the monoclinic structure and associated simulated patterns show the existence of a monoclinic superstructure with space group P2 or P2/m. - Highlights: • A new monoclinic BiLuWO{sub 6} phase has been elaborated from solid-state reaction. • The space group of the monoclinic disordered average structure should be A2/m. • Transmission electron microscopy leads to a superlattice with P2/m space group. • Raman spectroscopy suggests existence of local disorder.

  16. High efficiency, hybrid electrochromic device on polycarbonate substrates with neon sputtered WO3-x thin films

    OpenAIRE

    2016-01-01

    Electrochromic materials change color reversibly by applying an external DC voltage. One among the many emerging application of electro-chromics is the smart windows. The coloration efficiency, the optical colour modulation and the cyclability are the factors that bench mark the device. Tungsten oxide (WO3-x) is versatile material and reactive DC magnetron sputtering (with argon as sputter gas) technique is common for electro-chromics. In the present communication we have prepared tungsten ox...

  17. Synthesis, Analysis, and Testing of BiOBr-Bi2WO6 Photocatalytic Heterojunction Semiconductors

    OpenAIRE

    Xiangchao Meng; Zisheng Zhang

    2015-01-01

    In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6 photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantl...

  18. Direct observation of photoinduced charge redistribution of WO3-TiO2 double layer nanocomposite films by photoassisted Kelvin force microscopy

    Science.gov (United States)

    Wang, S. J.; Cheng, G.; Jiang, X. H.; Li, Y. C.; Huang, Y. B.; Du, Z. L.

    2006-05-01

    The microscopic photoinduced charge redistribution between heterogeneous semiconductor nanofilms of WO3 and TiO2 double layers (written as WO3-TiO2 nanocomposite films) was directly observed using Kelvin probe force microscopy (KFM) coupled with an UV light source. Under illumination the surface potential morphologies of WO3-TiO2 nanocomposite films changed from 162to592mV, which was associated with the photoinduced charge transfer between WO3 and TiO2 nanoparticles due to the energy level alignment between them. This improved technique of photoassisted KFM was presented to visualize the photoinduced charge transfer between different semiconductor nanoparticles on microscopic scale.

  19. Fabrication and photocatalytic activity enhanced mechanism of direct Z-scheme g-C3N4/Ag2WO4 photocatalyst

    Science.gov (United States)

    Zhu, Bicheng; Xia, Pengfei; Li, Yao; Ho, Wingkei; Yu, Jiaguo

    2017-01-01

    Herein, a direct Z-scheme graphitic carbon nitride (g-C3N4)/silver tungstate (Ag2WO4) photocatalyst was prepared by a facile in situ precipitation method using g-C3N4 as a support and silver nitrate as a precursor. X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and elemental mapping demonstrated that β-Ag2WO4 nanoparticles were evenly distributed on the surface of g-C3N4 nanosheets, which acted as a support for the nucleation and growth of β-Ag2WO4 and inhibited the phase transformation of metastable β-Ag2WO4 to stable α-Ag2WO4. Photocatalytic experiments indicated that the g-C3N4/Ag2WO4 nanocomposite photocatalyst displayed a better photocatalytic activity than pure g-C3N4 and Ag2WO4 toward the degradation of methyl orange. The enhanced photocatalytic performance of g-C3N4/Ag2WO4 could be well explained by a direct Z-scheme photocatalytic mechanism. This mechanism was related to the efficient space separation of photogenerated electron-hole pairs and the great oxidation and reduction capabilities of the g-C3N4/Ag2WO4 system. This work provided new insights into the design and fabrication of g-C3N4-based direct Z-scheme photocatalysts.

  20. Room-temperature deposition of nanocrystalline PbWO 4 thin films by pulsed laser ablation

    Science.gov (United States)

    Ryu, J. H.; Yoon, J.-W.; Shim, K. B.; Koshizaki, N.

    2006-07-01

    Pulsed laser ablation (PLA) was applied to synthesize nanocrystalline PbWO4 thin films onto glass substrates. The effects of Ar background gas pressure on phase evolution, microstructures and optical characteristics of PbWO4 thin films were investigated in detail. The PLA processes were carried out at room temperature without substrate heating or post-annealing treatment. XRD and HR-TEM results revealed that the PbWO4 thin films are composed of nanocrystalline and amorphous phases. Moreover, the films contained a high density of lattice defects such as twin boundaries and edge dislocations. The crystallite size and crystallinity increased, which were associated with a change in surface morphology as the Ar pressure increased. Reduced tungsten states W5+ or W4+ induced by oxygen vacancies were observed at 10 Pa and the atomic concentration of all constituent element was almost stoichiometric, especially the [Pb]/[W] ratio, which was nearly unity above 50 Pa. The optical energy band-gap was 3.03 eV at 50 Pa and increased to 3.35 eV at 100 Pa, which are narrower than the reported value (4.20 eV). This optical band-gap narrowing could be attributed to localized band-tail states and new energy levels induced by the amorphous structure and inherent lattice defects.