Sample records for hakei wo mochiita

  1. Active SWD using monochromatic source wavelet; Tan`itsu shuhasu no shingen hakei wo mochiita active SWD

    Tsuru, T.; Kozawa, T. [Japan National Oil Corp., Tokyo (Japan); Taniguchi, R. [Mitsubishi Electric Corp., Tokyo (Japan); Nishikawa, N. [Fuji Research Institute Corp., Tokyo (Japan); Matsuhashi, K.


    As part of developing efforts for physical exploration technologies for oil reservoirs, this paper describes development of an active seismic while drilling (SWD). The SWD is a seismic exploration method to acquire records equivalent to VSP using seismic waves generated from a bit executing excavation, and is capable of detection and control on a real time basis during the excavation. However, the drawback is that it is subjected to a limitation in the bit. To eliminate this limitation, an artificial seismic source method was devised. In other words, this is an SWD utilizing an artificial seismic source. The contrivance is such that a shot sub containing a magnetic distortion oscillator is attached directly above a bit to generate vibration artificially, and try to utilize larger seismic energy by combining this vibration with that generated from the excavating bit. Frequency band in the seismic source is as narrow as nearly a single frequency waveform. Preparing a time-depth curve from the data and identifying position of a bit making excavation requires reading the initial travel time. A waveform recognition technology was applied, which utilizes a matching evaluation function used in pattern recognition. This made waveform recognition possible at high accuracy. 2 figs., 1 tab.

  2. Optimization of the ship type using waveform by means of Rankine source method; Rankine source ho ni yoru hakei wo mochiita funagata saitekika ni tsuite

    Hirayama, A.; Eguchi, T. [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)


    Among the numerical calculation methods for steady-state wave-making problems, the panel shift Rankine source (PSRS) method has the advantages of rather precise determination of wave pattern of practical ship types, and short calculation period. The wave pattern around the hull was calculated by means of the PSRS method. The waveform analysis was carried out for the wave, to obtain an amplitude function of the original ship type. Based on the amplitude function, a ship type improvement method aiming at the optimization of ship type was provided using a conditional calculus of variation. A Series 60 (Cb=0.6) ship type was selected for the ship type improvement, to apply this technique. It was suggested that optimum design can be made for reducing the wave making resistance by means of this method. For the improvement of Series 60 ship type using this method, a great degree of reduction in the wave making resistance was recognized from the results of numerical waveform analysis. It was suggested that the ship type improvement aiming at the reduction of wave-making resistance can be made in shorter period and by smaller labor compared with the method using a waveform analysis of cistern tests. 5 refs., 9 figs.

  3. Sensing of subsurface faults based on an imaging technique for teleseismic waveform data. 2. Feasibility study for application to oblique incidence, multi-event and noise data; Enchi jishin hakei data wo mochiita chika kozo imaging ni yoru chichu danso kenshutsu no kokoromi. 2. Naname nyusha, multi event, noise wo fukumu hakei eno tekiyo

    Murakoshi, T.; Takenaka, H.; Saita, T. [Kyushu University, Fukuoka (Japan). Faculty of Science; Suetsugu, D. [Building Research Institute, Tokyo (Japan); Furumura, T. [Hokkaido University of Education, Sapporo (Japan)


    An examination was made on the method in which imaging of subsurface was carried out with teleseismic waveform data for sensing of faults. In the examination, an experiment was done on the sensing of faults with higher precision, by applying oblique incidence as well as perpendicular upward incidence of SH plane waves, and thereby stacking the imaging in plural events. In numerical experiments, 28 observation points were arranged at 500m spaces apart on the surface, and the incident waves were made the SH plane waves having a bell-shaped time function, with incidence made at an angle varied as 0{degree}, +15{degree} and -15{degree} from the lowest layer of a model. In the calculation of the wave motion field, a difference calculus with secondary accuracy was used for both time and space. In addition, data was prepared with a random noise added to a synthesized waveform to be used as observation data. The calculated waveform data were likened to the observation waveform, to which the method for imaging faults was applied. Consequently, it was noted that satisfactory results were obtained compared with the case where faults were sensed by one event alone. 5 refs., 4 figs.

  4. Trial to active SWD using artificial energy source. Use of monochromatic source wavelet; Jinko shingen wo mochiita SWD eno kokoromi. Tan`itsu shuhasu no shingen hakei no riyo

    Tsuru, T.; Kozawa, T. [Japan National Oil Corp., Tokyo (Japan); Taniguchi, R. [Mitsubishi Electric Corp., Tokyo (Japan); Matsuhashi, K. [Matsuhashi Techno Research, Hiroshima (Japan); Nishikawa, N. [Fuji Research Institute Corp., Tokyo (Japan)


    Seismic while drilling (SWD) is an accurate and safe method for drilling, by which real-time information regarding bit location and bedding boundary below the bit can be predicted by using elastic wave during drilling of rocks in a borehole. However, the signal level is rather low compared with the noise generated from the rig during drilling, resulting in the deteriorated data quality. Since the impact resiliency is small in soft beds, it is difficult to obtain good data due to the small energy of seismic wave propagating along drilling pipe. In order to overcome these problems, active SWD method using artificial seismic source has been developed. This method provides stable low-frequency seismic wave with large energy by the artificial seismic source adopting spring-mass system resonance method. Although the seismic source wave is monochromatic, the direct wave can be sufficiently analyzed and the bit location can be detected on the time profile of seismic prospecting. Protection of borehole damage during dropping of the equipment, energy propagation efficiency in the beds, and analysis of reflected wave are future problems. 11 refs., 6 figs., 4 tabs.

  5. 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

    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


    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.

  6. Preparation of spherical fine particulate pigments within water-in-oil emulsions and their properties. (II). ; Formation mechanism and characteristic of spherical fine particulate pigment of tartrazine. W/O emulsion wo mochiita kyujo biryushi ganryo no chosei to seishitsu(dai 2 ho). ; Kiiro 4 go kyujo biryushi ganryo no seisei kiko to tokusei

    Imai, T.; Iwano, K.; Hotta, H.; Takano, S.; Tsutsumi, H. (Kao Corporation, Tokyo (Japan))


    The previous report explained that an excellent spherical particulate pigment with a grain size of 0.5 mm or less can be obtained by preparing multinuclear aluminum lakes from acidic dyes and multinuclear aluminum salt using water droplets in a W/O emulsion as reaction fields. This paper describes preparing pigments varying the charging concentrations of the pigments in a W/O emulsion and the droplet particle size to discuss the mechanism of forming the pigments. As a result, it was found that the particle sizes in the produced pigments have a clear correlation with the charging concentrations of the pigments and the droplet particle sizes in the W/O emulsion. A pigment produced in the W/O emulsion forms only in its own droplets, and reflects its particle sizes. Films dispersed with pigments having different particle sizes were prepared to discuss their tinting abilities, whereas it was clarified that the smaller the particle size, the higher the tinting ability and the higher saturation in colored paint films. 6 refs., 9 figs., 3 tabs.

  7. Peltier heat flux sensor for cryogenic use; Peruchie soshi wo mochiita teion netsuryusoku sensa

    Haruyama, T. [High Energy Accelerator Research Organization, Tsukuba (Japan)


    It was evaluated as cryogenic heat flux sensor, which could measure the Peltier element in In situ in thermal flux. The equipment which could proofread the thermal flux was manufactured, and on marketed several kinds general-purpose Peltier element of, the relationship between thermal flux and thermoelectromotive force at the liquid nitrogen temperature was examined. (NEDO)

  8. Inertia charging system with a rotary valve. Kaitenben wo mochiita kansei kakyu system

    Sakai, H.; Ji, D. (The University of Tokyo, Tokyo (Japan). Faculty of Engineering); Kanesaka, H.; Lee, D.


    An inertia charger which is used to raise the output of an internal combustion engine can raise the volumetric efficiency by using the dynamic effect of intake air vibration which takes place in the intake system during the intake process. This paper described the trial manufacturing of an inertia charging system aiming at the high volumetric efficiency by arranging the rotary valve in the intake passage and by adjusting the operating time of the rotary valve and the studied result to improve the effect of inertia charging over the wide range of engine rotational speed. The experimental equipment was a 399cc single cylinder gasoline engine for a bicycle to which intake port a rotary valve was fitted. The engine number of rotation, volumetric efficiency, crank angle and the pressure change near the rotary valve were studied. As a result, the aerofoil rotary valve could improve the volumetric efficiency over a wide range of engine number of rotation, compared with the conventional inertia charging system. The optimized calculation result by which the future expansion of this system was studied, was shown. 3 refs., 4 figs., 3 tabs.

  9. Measurement of sediments thickness by ground penetrating radar; Denjihaho wo mochiita kotei taisekibutsu soatsu no sokutei

    Nozawa, E. [Tokyo Electric Power Co. Inc., Tokyo (Japan); Inagaki, M.


    An attempt was made to measure thickness of a layer of reservoir bottom sediments by utilizing the electromagnetic reflection method. Because water is a substance difficult for electromagnetic waves to permeate, considerations were given on to suppress attenuation to a minimum, and improve receiving sensitivity. The test used monocycle pulses with a central frequency of 200 MHz. In order to generate stabilized pulses with little unnecessary reflection, an antenna as large as it can be fitted into a rubber boat was employed. In order to acquire referential data, the test was carried out by using simultaneously a sound wave exploration device. The lake at which the test was carried out is a regulating reservoir with a size of about 250 m {times} 150 m, with its bottom made of concrete slab. This means that the lake consists of a three-layer structure comprising water, soil deposits, and concrete bottom from the water surface. According to an example of acquired electromagnetic exploration records, boundary reflection of water and sediments was observed clearly at water depths of 2 to 3 m as a shallow portion and 5 to 6 m as a deep portion. Reflection between the sediments and the bottom plate was also observed sufficiently distinctly. 3 refs., 8 figs.

  10. High resolution resistivity profiling using STRATAGEM system; Stratagem wo mochiita kobunkainohi teiko kozo tansarei

    Yamane, K.; Inoue, J.; Takasugi, S. [GERD Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan); Inazaki, T. [Public Works Research Institute, Tsukuba (Japan)


    A tensor type CSMT method (STRATAGEM) was introduced for the purpose of investigating shallow subsurface, and a field test has been carried out thereon. This system consists of a transmission section, and a sensor section and a data acquisition and processing section to observe waveforms in a responsive electromagnetic field. The signal source is a semi-circular air loop with a radius of a little smaller than 2 m. The measuring points were selected at locations about 200 m apart from the signal source to measure two electric field components and two magnetic field components by using sensors installed on the ground surface. The field test was performed at the Yutsubo area in Oita Prefecture, Japan. The electric field dipole is basically 5 m long, while S and E lines are 10 m long. The measurement frequency ranges from 96 kHz to 1000 kHz. The measurement time was about five minutes, and the whole measurement work including apparatus set-up and withdrawal was completed in about 15 minutes to minimize interference with the field which is a meadow. The field test result revealed that resistivity profile in shallow subsurface can be obtained much more easily than with the conventional CSMT method. 2 refs., 10 figs.

  11. Estimation of fracture aperture using simulation technique; Simulation wo mochiita fracture kaiko haba no suitei

    Kikuchi, T. [Geological Survey of Japan, Tsukuba (Japan); Abe, M. [Tohoku University, Sendai (Japan). Faculty of Engineering


    Characteristics of amplitude variation around fractures have been investigated using simulation technique in the case changing the fracture aperture. Four models were used. The model-1 was a fracture model having a horizontal fracture at Z=0. For the model-2, the fracture was replaced by a group of small fractures. The model-3 had an extended borehole diameter at Z=0 in a shape of wedge. The model-4 had a low velocity layer at Z=0. The maximum amplitude was compared each other for each depth and for each model. For the model-1, the amplitude became larger at the depth of the fracture, and became smaller above the fracture. For the model-2, when the cross width D increased to 4 cm, the amplitude approached to that of the model-1. For the model-3 having extended borehole diameter, when the extension of borehole diameter ranged between 1 cm and 2 cm, the change of amplitude was hardly observed above and below the fracture. However, when the extension of borehole diameter was 4 cm, the amplitude became smaller above the extension part of borehole. 3 refs., 4 figs., 1 tab.

  12. Trial to active seismic while drilling; Jinko shingen wo mochiita SWD eno kokoromi

    Tsuru, T.; Kozawa, T. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center


    This paper describes the development of a more stable SWD system with larger energy by adding an artificial seismic source near the bit. SWD is a technique by which the seismic wave generated while drilling of rocks by bit can be observed on the ground surface and the records equivalent to the reverse VSP can be obtained. For this system, a shell with a vibrator was fixed immediately on the bit as a sub-generator, and total energy of usual impact by the bit and vibration by the vibrator was used as a seismic source for SWD. For the seismic wave generation mechanism of this vibrator, the shell was resonated by the magnetostrictive element, and vibration was given to the bit and drilling pipe. When this seismic source is used, only single frequency is obtained for each vibration due to the utilization of resonance of shell. Therefore, the generation patterns should be made, by which wide band energy can be obtained after the interaction. Since the survey was conducted using this bottom hole seismic source at the drilling depth more than 3,000 m, it was necessary to enhance the vibration energy. 2 refs., 2 figs.

  13. New seismic source `BLASTER` for seismic survey; Hasaiyaku wo shingen to shite mochiita danseiha tansa

    Koike, G.; Yoshikuni, Y. [OYO Corp., Tokyo (Japan)


    Built-up weight and vacuole have been conceived as seismic sources without using explosive. There have been problems that they have smaller energy to generate elastic wave than explosive, and that they have inferior working performance. Concrete crushing explosive is tried to use as a new seismic source. It is considered to possess rather large seismic generating energy, and it is easy to handle from the viewpoint of safety. Performance as seismic source and applicability to exploration works of this crushing explosive were compared with four kinds of seismic sources using dynamite, dropping weight, shot-pipe utilizing shot vacuole, and impact by wooden maul. When considered by the velocity amplitude, the seismic generating energy of the crushing explosive of 120 g is about one-fifth of dynamite of 100 g. Elastic wave generated includes less high frequency component than that by dynamite, and similar to that using seismic source without explosive, such as the weight dropping. The maximum seismic receiving distance obtained by the seismic generation was about 100 m. This was effective for the slope survey with the exploration depth between 20 m and 30 m. 1 ref., 9 figs., 2 tabs.

  14. Recent design example with prestressing techniques; Prestressing wo mochiita kozo sekkei 2 dai

    Kawaguchi, M. [Hosei University, Tokyo (Japan). Faculty of Engineering


    This paper describes two examples of non-concrete prestressing techniques. The first example is a soccer stadium. The system to support the roof consists of members (steel rods) that compress and stretch the roof. Premoulded prestressed concrete piles are used for columns. Prefabricated members are also used for other parts of the upper stand structure. The upper stand structure consists of 25 PHC pile columns and precast concrete. Vertical braces are arranged between the columns. The load of the stands are supported by cast-in-place concrete and PHC columns. In this structure, the axial force represents the main flow of force, allowing each member to be utilized with its highest sectional performance. The second example is a footbridge leading to a park. Natural granite stones are used for the top chord members of the imperfect truss. The stones are laid side by side, and are tied with five PC cables into a single stone. Prestress is applied to the stones to suppress tensile force. Thrust of the stones are offset by tensile force of the bottom chord members. 19 figs., 2 tabs.

  15. Biped locomotion control with compliance; Compliance wo mochiita nisoku soko robot no undo seigyo

    Kawaji, S.; Ogasawara, K.; Iimori, J. [Kumamoto University, Kumamoto (Japan)


    Realization of stable walking motion of biped locomotive robot is one of difficult control problems, but it is very interesting both theoretically and practically from the view point of motion control. The authors have already reported that the locomotion rhythm plays an important role in walking motions, and confirmed experimentally that the control method based on the locomotion rhythm is effective. But, many uncertainties, e.g., the changes of robot dynamics and the interaction between the robot and the floor, may make the locomotion rhythm irregular. In this paper, we introduce the compliance into the control system in order to modify the original reference locomotion rhythm for stable walking under the existence of the uncertainties. Concretely a compliance control system for the contact leg is designed to modify the rhythm by changing the posture of the leg corresponding to the force acting from the body so that the robot may keep the equilibrium state dynamically. Finally the simulation results are given to illustrate the effectiveness of the proposed compliance control system. 21 refs., 12 figs., 3 tabs.

  16. Shallow PS-logging by high frequency wave; Koshuha wo mochiita senbu PS kenso

    Nakajima, A.; Miyazawa, M.; Azuma, H. [OYO Corp., Tokyo (Japan)


    This paper describes the following matters on down-hole PS logging in shallow subsurface. Determining an elastic wave velocity structure in shallow subsurface with high accuracy by using down-hole PS logging requires reduction of errors in reading travel time. Therefore, a high-frequency vibration source was fabricated with an objective to raise frequencies of waves used for the measurement. Measurements were made on two holes, A and B, at a measurement interval of 0.5 m, whereas at the hole A a measurement was performed simultaneously by using a normal type (low-frequency) vibration source. A spectral analysis on the waveform record revealed that the frequencies with each vibration source were 127 Hz and 27 Hz for the hole A, 115 Hz for the hole B, and the S/N ratio was all the same for both holes. When the high-frequency vibration source was used, the velocity was determined at accuracy of 5% over the whole length of the shallow section. When the low-frequency vibration source was used, sections with the velocity determining error greater than 5% were found, and it was not possible to derive the velocity structure in the shallow subsurface in fine segments. 3 refs., 8 figs., 2 tabs.

  17. Reservoir characterization using artificial neural network; Neural network wo mochiita choryuso tokusei kaiseki

    Shimada, N.; Kozawa, T. [Japan National Oil Corp., Tokyo (Japan); Nishikawa, N.; Tani, A. [Fuji Research Institute Corp., Tokyo (Japan)


    Neural network is used for the prediction of porosity and permeability using logging data as reservoir characteristics, and the validity of this method is verified. For the prediction of reservoir characteristics by the use of seismic survey data, composite seismic survey records obtained by density logging and acoustic logging are used to experiment the prediction of porosity and permeability continuous along lines of wells. A 3-output back propagation network is used for analysis. There is a possibility that this technique when optimized will improve on prediction accuracy. Furthermore, in the case of characteristics mapping, 3-dimensional seismic data is applied to a carbonate rock reservoir for predicting spatial porosity and permeability. This technique facilitates the comprehensive analysis of core data, well data, and seismic survey data, enabling the derivation of a high-precision spatial distribution of reservoir characteristics. Efforts will continue for further improvement on prediction accuracy. 6 refs., 7 figs., 3 tabs.

  18. Lightning position detecting system using OPGW; OPGW wo mochiita rakurai ichi tanchi system

    Kurihara, M. [Central Research Institute of Electric Power Industry, Tokyo (Japan)


    Discussions were given to utilize an optical fiber composite aerial ground wire (OPGW) not only as an information transmission path, but also for lightning detection. Power transmission lines are installed with aerial ground wires for lightning shielding, into which optical fibers were assembled to make the system an OPGW. An optical loop is constructed, in which optical signals admitted to an incidence end is turned back at an OPGW end opposing the incidence end so that the optical signals return back to the incidence end. If an OPGW is hit by lightning, a lightning current flows through steel towers as the grounding path. This current flow generates a magnetic field inside the OPGW, causing simultaneously polarized rotation (a Faraday effect) in the same direction in the optical signals going back and forth in the optical loop. When this is observed at the incidence end, polarizing variation is observed twice with a certain time difference, which corresponds to two times of the distance between the lightning point and the turn-back point. Thus a distance to the lightning point can be derived. As compared with other identification systems, this method is characterized by capability of collecting lightning information along power transmission lines at one point, no necessity of a device to be connected to a transmission line, and no necessity of comparative information or clock synchronization. 4 refs.

  19. Control of mechatronic systems using electrorheological fluids; ER ryutai wo mochiita mekatoronikusu kiki no seigyo

    Furusho, J. [The Univ. of Electric Communications, Tokyo (Japan)


    ER fluids (electrorheological fluids) are fluids whose rheological properties vary due to an electric field, and at the present, its development is being vigorously carried forward with the objective of its application to various mechanical systems. The ER fluids which are the objects for its development are two kinds, namely ER suspensions and homogeneous fluids using liquid crystals. Concerning the ER suspensions, its study started from the latter half of 1940`s, but the history of studying the homogeneous ER fluids is short. In this article, comparison is made between the ER suspensions and the homogeneous ER fluids. Regarding the comparison in their application fields, several differences are enumerated including that the response time of the ER suspensions to the change of the electric field is considerably faster than the homogeneous fluids using liquid crystals. As examples of the application of the ER suspensions, ER valves, application to automobiles, ER dampers, vibration control of structures, and ER clutches are shown and likewise, as examples of the application of the homogeneous ER fluids, robot arm control, dampers, etc.. Also its application to robotics is described. 51 refs., 8 figs., 1 tab.

  20. Method to remove poisonous chlorine compounds using supercritical carbon dioxide. Chorinkai tansan gas wo mochiita yudoku enso kagobutsu no jokyoho

    Ikushima, Y. (Government Industrial Research Institute, Tohoku, Sendai (Japan))


    This paper describes a method to extract and remove selectively poisonous chlorine compounds from aqueous solution using supercritical CO2. This method is characterized in that it extracts and separates only chlorine compounds in short time under a moderate condition, and removes it without a need of whatever post-treatment. The supercritical CO2 pressure was 80 kg/cm[sup 2], and the extraction temperature was 40[degree]C. The supercritical CO2 extracted 70% to 80% by weight of trichloroethylene and tetrachloroethylene in 15 to 30 minutes, almost all of 1,2-dichloroethane and 1,1,1-trichloroethane in one hour, and about 70% by weight of benzil chloride after 90 minutes. When the supercritical CO2 extraction was carried out for a dilute chlorine compound at 1000 ppm for three hours, the concentrations of trichloroethylene and tetrachloroethylene in the aqueous solution decreased down to several ppm, with no other substances than chlorine compounds detected in the extracts. This proves that no water has been extracted at all. 5 figs., 1 tab.

  1. Preparation of ion-exchange thin film using plasma processes. Plasma process wo mochiita ion kokansei usumaku no sakusei

    Ogumi, Z.; Uchimoto, Y. (Kyoto University, Kyoto (Japan). Faculty of Engineering)


    The present report describes a study which aims at preparation of a new functional film by plasma polymerization. For this purpose, 4-vinylpyridine monomer is plasma-polymerized to obtain a thin film, which is quaternarized with 1-bromopropane to produce an anion exchange thin film, which is laminated on the surface of a cation-exchange film to make a mono-valent cation perm-selective film. In plasma-polymerization, the relations of polymerizing pressure, as parameter, to the deposition rate of the polymerizerd film and the characteristics of compound were clarified. In preparing the anion-exchange thin film, the preparation of uniform ultrathin films with no pinhole was attempted. For this purpose, the transference number of Cl[sup -] was measured so as to confirm that Cl[sup -] is uniformly distributed and fixed cation groups are distributed uniformly in the film. The perm-selective film exhibited a high mono-valent cation perm-selectivity while its film resistance was increased. This increase is found to be broken down to the resistance of the plasma-polymerization film layer and the resistance of the film interface. The latter arises from the implantation of nitrogen-cointaining species in the plasma onto the surface of the cation exchange film. 26 refs., 10 figs., 2 tabs.

  2. Batch process. Flexible paint production system using movable tanks; Idoso wo mochiita toryo no flexible seisan system

    Yamashita, S. [Kansai Paint Co. Ltd., Hiratsuka, Kanagawa (Japan). Central Lab.


    In the paint manufacturing industry, there are many kinds of product depending on the use, and there are few kinds of paint which can be manufactured by a large facility capable of producing several tens of kL of paint. An average working ratio of facility in this industry is limited to between 60 to 70%, and the ratio of the personnel expense to the cost has recently increased. The changing to an FMS (Flexible Manufacturing System) for increasing the working ratio of the facility and the changing of the system to greatly improve the operation efficiency have been demanded. The concrete means for these requirements include changing the facility to a pipeless one. The paint manufacturing facility comprises four sections, i.e. a premixing section, dispersing section, mixing section and canning section. If the mixing tank is made movable and the equipment on the preceding and succeeding stages of the mixing tank is made pipeless, the facility can be changed to the one not substantially restricted by the quality of products from the dispersing section to the filtration section which can be formed. However, the drawbacks of this system include the following: a failure, if it occurs, influences the whole production line; learning the system operating method requires much time, causing many initial failure occur; and great expansion of the facility is difficult. 2 refs., 2 figs., 2 tabs.

  3. Index of powered support performance in terms of global stiffness matrix. Gosei matrix wo mochiita jiso shiho no seino hyoji

    Sato, K.; Itakura, K.; Hirose, K. (Muroran Institute of Technology, Hokkaido (Japan))


    Powered supports were tentatively analyzed to establish a new index for evaluation of their performance. The new index was deduced by comparing the deformation characteristics of various powered supports mutually. The deformation characteristics of a powered support was able to be indicated in terms of a (2 {times} 2) global stiffness matrix. The global stiffness matrix depended on the mining height of powered support. The stiffness of hydraulic legs mainly determined the convergence component of the global stiffness, whereas the stiffness of caving shield determined its shear component. The convergence performance tended to sacrifice the shear deformation one, and vice versa. The principal direction of the global stiffness matrix allowed to select well-balanced deformation characteristics. To assure deformation performance as properly as possible, it was shown that the principal axis of the global matrix should be tilted by 15 to 25 degrees of the angle from the vertical towards the canopy tip. 4 refs., 13 figs., 2 tabs.

  4. Evaluation of paramagnetic species in coals with iodine doping technique; Yoso tenkaho wo mochiita sekitanchu no jojiseishu no hyoka

    Aizawa, S.; Kumagai, H.; Chiba, T. [Hokkaido University, Sapporo (Japan). Center for Advanced Research of Energy Technology


    Electron paramagnetic resonance (EPR) of coals was considered by using iodine doping technique. Sub-bituminous coal (WA) and bituminous coal (UF) were used to observe EPR spectra using microwaves. With the UF coal, strength of the narrow component of the spectra was found constant regardless of amount of the doped iodine, wherein radicals without interaction with iodine were detected. Strength of the broad component increased with the iodine doping amount, where in deviation of {pi} electrons was detected, which have been generated as a result of interaction between aromatic rings and iodine in the coals. Spin concentration of the WA coal with low coalification degree is constant regardless of the iodine doping amount, and the interaction of the iodine with the aromatic rings was found small. The higher the coalification degree, the more the aromatic ring structure grows, and electron donor capability for the iodine increases. In a system with the entire spin being uniform, the spectrum height shows a saturation phenomenon against increase in microwave output. A non-uniform system, in which the oriented spin forms small groups and is in local thermal equilibrium, does not show saturation, but increases monotonously. 2 refs., 5 figs.

  5. Evaluation of column flotation results with a film flotation method; Film fusenho wo mochiita column fusen kekkan no hyoka

    Fujimoto, H.; Matsukata, M.; Ueyama, K. [Osaka University, Osaka (Japan). Faculty of Engineering Science


    Change in wettability of coal particle surfaces due to kerosene adsorption was studied by using a film flotation method. The applicability of a film flotation method to coals modified by kerosene adsorption was first confirmed. In experiment, film flotation was applied to Illinois coal modified by aqueous methanol solution and kerosene adsorption, and the weight percent of residual particles on a gas-liquid interface and kerosene in aqueous methanol solution were analyzed to verify the applicability of a film flotation method. Film flotation was applied to Datong and Illinois coals modified by kerosene adsorption, and the weight percent of residual particles on a gas-liquid interface was plotted to surface tension of liquid. As a result, the weight percent of hydrophobic particles within 50mN/m in surface tension slightly increased in Datong coal and remarkably increased in Illinois coal with kerosene addition. It was thus suggested that in addition to surface tension, the distributions of hydrophilic and hydrophobic strengths on the surface of each coal particle should be considered to understand attachment of coal particles and bubbles. 6 refs., 4 figs.

  6. DC servo motor control using digital signal processors; Digital keisoku seigyo. 6. DSP wo mochiita DC servo motor seigyo

    Sato, T. [Max Co. Ltd., Tokyo (Japan)


    A digital control development effort is introduced, citing a case of DSP (digital signal processor)-aided DC servo motor control for the flat head type pen plotter. In a real plotter, a complicated nonlinear problem will arise because the natural frequency varies dependent upon the pen position. For the inhibition of such vibration which occurs during acceleration and deceleration, nonlinear elements have to be taken into consideration at the designing stage. In this report, the effort is focused on motor axis control only, and the DC servo control problem is solved as a linear problem. A DSP board type DS1102 of the dSPACE Corporation is named for this work. Using this board, the C code is automatically generated out of a control block constructed through SIMULINK, and a real-time test is conducted after downloading the code to the DSP processor. Since the quantity of DC servo motor rotation is quantized in an encoder, the result would contain much error and cause instability in the control if the quantity as obtained was subjected to differential calculus. Such being the case, velocity data for the control in this report are acquired by use of an observer. (NEDO)

  7. Delivery of antisense oligonucleotide into cells using synthetic peptide; Gosei pepuchido wo mochiita anchisensu origonukureochido no saibounai donyu

    Niidome, Takuro [Nagasaki University, Nagasaki (Japan). Dept. of Applied Chemistry


    Much attention has been attracted to the antisense oligonucleotide as a novel nucleic acid medicine. However, many problems to be solved such as delivery system in vivo and permeation through cell membrane are pointed out. In this study, we found out that some cationic peptides were useful as an oligonucleotide-carrier molecule into cells. Furthermore, to develop a cell specific gene delivery system using the cationic peptide, we modified the peptides with several galactose residues. As a result, the modified peptides showed high transfer efficiencies into hepatoma cells, and then, it was clear that the internalization into cells was mediated by asialoglycoprotein receptor on hepatoma cell. (author)

  8. Experiment of exploration using the active-faults exploration system; Katsudanso tansa system wo mochiita chika tansa jikken

    Mikada, H.; Sato, H.; Iwasaki, T.; Hirata, N. [The University of Tokyo, Tokyo (Japan). Earthquake Research Institute; Ikeda, Y. [The University of Tokyo, Tokyo (Japan). Faculty of Science; Ikawa, T.; Kawabe, Y.; Aoki, Y. [JAPEX Geoscience Institute, Tokyo (Japan)


    A system for exploration of active-faults by seismic reflection profiling method was introduced at Earthquake Research Institute, University of Tokyo. A test-run was conducted to check the performance of this system at Ranzan, Saitama Prefecture. This paper describes the confirmed performance of mini-VIB as a wide band frequency seismic source, the quality of data obtained using a digital data acquisition system, and problems for data processing of fault exploration in the future. For the test-run at Ranzan, two-dimensional exploration was conducted by the quasi-three-dimensional data acquisition method using three geophones of 8 Hz, 28 Hz, and 40 Hz, simply arranged in parallel on the measurement line. Using an active seismic vibrator, mini-VIB, data acquisition of faults in the wide band frequency was achieved, which would result in the highly accurate imaging. Operation of data acquisition and processing systems is easy, and the system can be also used as a kind of black box. The existing methods are to be used sufficiently as a tool for imaging of faults. Further research for accumulating experience may become necessary toward the extension of the system expected in the future. 5 refs., 6 figs.

  9. Temperature measurement of geothermal wells by optical fiber sensor; Hikari fiber sensor wo mochiita chinetsusei no ondo bunpu keisoku

    Matsushima, N.; Sakaguchi, K. [Geological Survey of Japan, Tsukuba (Japan)


    Experiments of temperature measurement were conducted in high temperature and high pressure geothermal wells using optical fiber sensor. A temperature measurement system using optical fiber sensor was applied to geothermal wells. Working availability was confirmed under the condition up to the depth of 1,750 m and the temperature of 240 centigrade. Observed values agreed well with those observed by the conventional temperature logging. Durability of the optical fiber sensor was also sufficient. The maximum standard deviations of measured values were 1.3 centigrade at the depth of 1,750 m at 195 centigrade for the loop-type sensor, and 3.7 centigrade at the depth of 365 m at about 200 centigrade for the single-end sensor. Although the accuracy was inferior to the conventional measurement using a thermo couple, it was enough to be applied to usual temperature logging. Furthermore, for this system, the temperature profile in the whole well can be monitored, simultaneously. Through the experiments, the detailed successive change of temperature profile accompanied with the water injection can be clearly illustrated. 3 refs., 7 figs.

  10. Development of economical and high efficient desulfurization process using low rank coal; Teitankadotan wo mochiita ankana kokoritsu datsuryuho no kaihatsu

    Takarada, Y.; Kato, K.; Kuroda, M.; Nakagawa, N. [Gunma University, Gunma (Japan). Faculty of Engineering; Roman, M. [New Energy and Industrial Technology Development Organization, Tokyo, (Japan)


    Experiment reveals the characteristics of low rank coal serving as a desulfurizing material in fluidized coal bed reactor with oxygen-containing functional groups exchanged with Ca ions. This effort aims at identifying inexpensive Ca materials and determining the desulfurizing characteristics of Ca-carrying brown coal. A slurry of cement sludge serving as a Ca source and low rank coal is agitated for the exchange of functional groups and Ca ions, and the desulfurizing characteristics of the Ca-carrying brown coal is determined. The Ca-carrying brown coal and high-sulfur coal char is mixed and incinerated in a fluidized bed reactor, and it is found that a desulfurization rate of 75% is achieved when the Ca/S ratio is 1 in the desulfurization of SO2. This rate is far higher than the rate obtained when limestone or cement sludge without preliminary treatment is used as a desulfurizer. Next, Ca-carrying brown coal and H2S are caused to react upon each other in a fixed bed reactor, and then it is found that desulfurization characteristics are not dependent on the diameter of the Ca-carrying brown coal grain, that the coal is different from limestone in that it stays quite active against H2S for long 40 minutes after the start of the reaction, and that CaO small in crystal diameter is dispersed in quantities into the char upon thermal disintegration of Ca-carrying brown coal to cause the coal to say quite active. 5 figs.

  11. Interferometric SAR and land deformation. Analysis using the dislocation model; Interferometric SAR to chikaku hendo. Dislocation model wo mochiita kaiseki

    Matsushima, J.; Otaki, T.; Tanaka, A.; Miyazaki, Y. [Geological Survey of Japan, Tsukuba (Japan)


    The diastrophism by the earthquake-induced dislocation is investigated by interferometry (INSAR) which represents the diastrophism by the interference fringes of equiphase difference lines. A joint research group at Geographical Survey Institute and National Space Development Agency showed the diastrophism in the vicinity of the ground surfaces before and after the Hyogoken Nanbu Earthquake by the INSAR interference images in 1995. This paper discusses the effects of observation in the vision line direction from the satellite and dislocation parameters on the interference images. The dislocation model uses a slanted rectangular model in a semi-infinite medium, to calculate static displacements and strain distributions at the ground surface, when dislocation changes. It is found that the INSAR interference images, detecting displacements in the vision line direction from the satellite, significantly change as the vision line direction changes, and that the actual displacement cannot be given by the images alone. This paper also shows sensitivity of the interference images to the dislocation parameters. 3 refs., 9 figs., 1 tab.

  12. Mine train control system by H{infinity} control; H{infinity} seigyo wo mochiita tanko makiage seigyo system

    Ouchi, s. [Tokai University, Tokyo (Japan). Faculty of Engineering; Liu, K. [Chiba University, Chiba (Japan). Faculty of Engineering; Sato, S. [Fuji Electric Corporate Research and Development, Ltd., Kanagawa (Japan); Mita, T. [Tokyo Institute of Technology, Tokyo (Japan). Faculty of Engineering


    Mine train control system is consisted of a winder, a train which transports many people to minebottom, and a long wire rope which connects a winder and a train. The mine train control system reported in this paper is the system with the longest rope of about 6700m in the world. This system often generate a rolling of train when the train stops at the station when using conventional control. In conventional systems, two mine train control systems of the length of 1/2 of all mining galleries were used in order to ristrict the rolling. In these systems, change time was necessary. However, this change time become unnecessary by using a system with the length of 6700m. When using this system, it is the main subject how to control the bigger rolling . We solved the problem on the rolling control of this system by using H{infinity} control, and got the result that the travel time of the train made 2/3 compared with that of the conventional systems using two mine train control systems, and the train speed of 420m/min which is the maximum speed in the world was achieved. 7 refs., 8 figs.

  13. Geotechnology for groundwater and salinisation soil using geophysical prospecting; Butsuri tansa wo mochiita chikasui enrui dojo no tansa gijutsu

    Chiba, A. [Sumitomo Metal Industries, Ltd., Osaka (Japan); Imaizumi, M.; Takeuchi, M. [National Research Institute of Agricultural Engineering, Tsukuba (Japan)


    This paper takes a general view of geophysical prospecting on groundwater and salinisation soil. It also explains the following examples of prospecting: an example of pursuing movement of saline water lump charged with a tracer by using a specific resistance monitor, as a monitoring survey being a representative example of `visualization of movement` expected as a direction to which physical prospecting should proceed in the future, an example of elucidating distribution of soil salts vertically and two-dimensionally by using the electromagnetic exploration method, and an example of surveying distribution of three-dimensional water permeation coefficients by utilizing geophysical prospecting systems, as an example of estimating property values from geophysical prospecting. Electrical prospecting has been used as an exploration method related to groundwater, whereas its method has been increasing the diversity, such as from vertical exploration to high-density horizontal exploration and tomography. Noticeable progress can also be seen in electromagnetic exploration and logging techniques. In addition, what is demanded in application of physical prospecting to groundwater field may include visualization of ground water flow, more precise estimation of hydraulic constants, and complement of their distribution. 22 refs., 21 figs., 3 tabs.

  14. Forced-circulation solar water heater using a solar battery; Taiyo denchi wo mochiita kyosei junkahshiki taiyonetsu onsuiki

    Asai, S.; Mizuno, T. [Yazaki Corp., Tokyo (Japan)


    Optimal operation control was discussed on a forced-circulation solar water heater using solar cells not only as the power supply of a heat collecting pump, but also for controlling operation of the heat collecting pump. With this system, when the amount of power generated by solar cells reaches a sufficient level for operating the heat collecting pump, the heat collecting pump starts operation, wherein the heat collecting medium circulates in the system. The discussion was given by using simulation based on experimental expressions such as the relation expression between insolation and heat collecting medium flow rate as derived from the result of the system`s heat collecting performance test. As a result, the following conclusions were obtained: optimal insolation for activating the discussed system is from 50 to 100 W/m {sup 2}, and the heat collected within this range is within -1.5% of the collected heat amount at an optimum value; optimal activating insolation for the case of 1000 to 2000 W/m {sup 2} with low daily cumulative insolation is from 0 to 50 W/m {sup 2}, whereas the optimal activating insolation amount increases as the daily cumulative insolation amount increases; and the optimal activating insolation amount increases as water to be supplied requires higher temperature. 1 ref., 17 figs., 2 tabs.

  15. Suppression of numerical dispersion using FD modified operators; Atarashii sabunho no enzanshi wo mochiita suchi bunsan no yokusei

    Takeuchi, N.; Geller, R. [The University of Tokyo, Tokyo (Japan). Faculty of Science


    The author, et al., have developed a formal evaluation theory for errors in numerical solutions and derived on the basis of this theory the conditions that a modified error minimizing operator should satisfy. A modified operator was derived for a calculus of finite difference in the time domain making use of this error evaluation theory. In this study, a modified operator was derived for O (2, 2) in the calculus of finite difference in time, and the operator was used in the calculation for the old and new methods about 1-dimension inhomogeneous media, and the two were quantitatively compared in CPU time and calculation accuracy. The calculation used 500 space grids and 5000 time grids. With the ratio of the time grid gap and space grid gap are kept constant, both CPU time and calculation accuracy were in proportion to the square of the number of grids. It was found in view of the result that the new method, as compared with the old method, needs only approximately 1/20 of CPU time in performing calculations of the same precision and that it maintains calculation accuracy that is approximately 20 times higher in the said CPU time. 4 refs., 2 figs., 1 tab.

  16. Reexamining results of Iwatoyama tumulus by means of directive antenna; Shikosei antenna wo mochiita Iwatoyama kofun no saijikken

    Okamoto, K. [Osaka Institute of Technology, Osaka (Japan); Kobayashi, Y. [Kyoto University, Kyoto (Japan); Yoda, M. [Shiga Prefecture Board of Education, Shiga (Japan)


    Investigation was conducted into the Iwatoyama tumulus located at Oaza Yoshida, Yame City, Fukuoka Prefecture, in January 1995, when a directional antenna was used. For the verification of the reliability of the result, another investigation was conducted in the same way. As in the previous effort, a traverse line of 18.8m was provided, and a sub-traverse line of the same length was provided 1m south of the traverse line. Reflection amplitude obtained during this investigation was smaller than that in the previous investigation, which was attributed to it that the contrast in dielectric constants between the rock constituting the main body in the cave and the cavity inside is high in winter and low in summer. In the second investigation, probably because the sub-traverse line was nearer to the southern end of the stone chamber, it became possible to evaluate the area of the stone chamber in the east-west direction, which confirms the conclusion of the first investigation that `it has to be inferred that the tumulus has its stone chamber ceiling at the depth of approximately 3.7m at a spot approximately 9.5-15.0m distant from the survey base for the round foot of the Iwatoyama tumulus and that therefore there exists a cave-type stone chamber with its ceiling 2.5-3.0m high.` 3 refs., 6 figs.

  17. Remote reference processing in MT survey using GPS clock; MT ho ni okeru GPS wo mochiita jikoku doki system

    Yamane, K.; Inoue, J.; Takasugi, S. [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan); Kosuge, S. [DRICO Co. Ltd., Tokyo (Japan)


    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.

  18. Improvement of two-dimensional gravity analysis by using logarithmic functions; Taisu kansu wo mochiita nijigen juryoku kaiseki no kairyo

    Makino, M.; Murata, Y. [Geological Survey of Japan, Tsukuba (Japan)


    An examination was made, in the two dimensional tectonic analysis by gravity exploration, on a method that was applicable from a deep underground part to a shallow geological structure by using logarithmic functions. In the examination, a case was considered in which an underground structure was divided into a basement and a covering formation and in which the boundary part had undulations. An equation to calculate a basement structure from a gravity anomaly was derived so that, taking into consideration the effect from the height of an observation point, it might be applicable to the shallow distribution of the basement depth. In the test calculation, a model was assumed reaching the depth near the surface with the basement being a step structure. Density difference was set as 0.4g/cm{sup 3}. An analysis using an equation two-dimensionally modified from Ogihara`s (1987) method produced a fairly reasonable result, showing, however, a deformed basement around the boundary of the step structure, with the appearance of a small pulse-shaped structure. The analysis using logarithmic functions revealed that the original basement structure was faithfully restored. 3 refs., 5 figs.

  19. Refrigerator cooled magnet using Ag-sheathed Bi-2212 tape; Bi-2212 kin fukugoka senzai wo mochiita reitoki reikyaku magunetto

    Okura, K.; Kaneko, T.; Hayashi, K.; Takei, H. [Sumitomo Electric Industries Corp., Osaka (Japan); Kasu, O. [Engineering Research Association for Superconductive Genertion Equipment and Materials, Osaka (Japan)


    The application to the coil in the 20K vicinity can be expected by the improvement in the refrigerating machine performance Bi2212 oxide superconductor. It is compared it in 20K in case of the superconducting coil at the conventional 4.2K, and the specific heat increases, and the coil becomes difficult to quench it, and there is the merit in which the stable energization becomes possible. Then, the result is reported, because the coil trial manufacture was carried out using Bi-2212 silver combination long length wire rod this time, and because the coil operation was carried out. (NEDO)

  20. Forced-circulation solar water heater using a solar battery; Taiyo denchi wo mochiita kyosei junkanshiki taiyonetsu onsuiki

    Asai, S.; Mizuno, T. [Yazaki Resources Co. Ltd., Shizuoka (Japan)


    For the purpose of satisfying demands for qualitative improvement on tapwater temperature and pressure, an indirect-type solar water heater using solar cells, in which a closed type hot water storage tank connected directly to the water supply is integrated with a solar collector, was examined for its characteristics and performance. The heat collecting medium is a water solution of polypropylene glycol, which circulates through the solar collector pump, cistern, solar collector, and heat exchanger (hot water storage tank). The results of the test are summarized below. When comparison is made between the two solar collector pump control methods, the solar cells direct connection method and the differential thermo method utilizing temperature difference between the solar collector and the hot water storage tank, they are alike in collecting heat on clear days, but on cloudy days the latter collects 5% more than the former. In winter, when the heat exchanger heat transfer area is 0.4m{sup 2} large, a further increase in the area improves but a little the heat collecting efficiency. An increase in the medium flow rate and temperature, or in the Reynolds number, enhances the heat collecting efficiency. 13 figs., 6 tabs.

  1. Performance analysis of dish solar stirling power system; Stirling engine wo mochiita taiyonetsu hatsuden system no seino yosoku

    Tsuchiya, K.; Yamaguchi, I. [Meiji University, Tokyo (Japan); Naito, Y.; Momose, Y. [Aisin Seiki Co. Ltd., Aichi (Japan)


    In order to estimate the performance of the dish solar Stirling power system, matching and control of each component system were studied, and the performance of the 25kWe class power system was estimated on the basis of direct solar radiation measured in Miyako island, Okinawa. Application of a Stirling engine to solar heat power generation is highly effective in spite of its small scale. The total system is composed of a converging system, heat receiver, engine/generator system and control system. As the simulation result, the generator output is nearly proportional to direct solar radiation, and the system efficiency approaches to a certain constant value with an increase in direct solar radiation. As accumulated solar radiation is large, the influence of slope error of the converging mirror is comparatively small. The optimum aperture opening ratio of the heat receiver determined on the basis of mean direct solar radiation (accumulated solar radiation/{Delta}t (simulated operation time of the system)), corresponds to the primary approximation of the opening ratio for a maximum total generated output under variable direct solar radiation. 6 refs., 6 figs., 1 tab.

  2. Magnetic sensor with silicon on insulator structure for high temperature applications; SOI kozo wo mochiita koon`yo jiki sensor

    Matsumoto, Y.; Kawai, H.; Terada, T.; Kawahito, S.; Ishida, M.; Nakamura, T. [Toyohashi University of Technology, Aichi (Japan)


    To enable stable magnetic measurement in high temperature surroundings, a Hall cell of the SOI structure (with a single-crystal Si layer formed on an insulating film) was experimentally fabricated, and its characteristics as a magnetic sensor were examined. This element can be mass-produced by use of the current semiconductor manufacturing technology. In the conventional method of element isolation using the pn-junction, backward leak currents across the pn-junction grow large at high temperatures, reducing sensitivity and increasing offset voltage (the Hall voltage at zero magnetic field) to disable the elements. Under the circumstances, an SOI structure in which elements are isolated by an SiO2 film were studied. Sensitivity and temperature characteristics are dependent on donor concentration. But there is a relationship of trade-off between sensitivity and the usable temperature range, and this means that a donor concentration fit for the given purpose needs be chosen. To inhibit the generation of the offset voltage, Hall element shapes and chip bonding methods were studied, and a magnetic sensor with an offset variation not more than {plus_minus}3mV was obtained. In an SOI magnetic sensor, the temperature range in which sensitivity remains constant expands as donor concentration is enhanced, and this permits the use of the SOI magnetic sensor in higher-temperature operations. 6 refs., 13 figs., 1 tab.

  3. Application of VSP to geological investigation; P ha oyobi S ha VSP wo mochiita shinso chishitsu chosa

    Kinugasa, Y. [Geological Survey of Japan, Tsukuba (Japan); Feng, S.; Sugiyama, T.; Ishikawa, K. [Chuoh Kaihatsu Corp., Tokyo (Japan)


    Discussed in this paper are the P-wave and S-wave zero-offset VSPs carried out utilizing boreholes located in Nada Ward, Kobe City, and Hokudan-cho, Hyogo Prefecture, as part of the deep layer boring survey following Hanshin Earthquake Disaster. This effort aims at the elucidation of P-wave and S-wave velocity structures, high-precision identification of data obtained by the surface reflection method, and collection of basic data for active faults investigation in the future. Among the velocity structures obtained for various layers, the S-wave velocity structures in particular agree with the stratigraphy excellently and may be utilized in seismic analyses to be conducted in the future. Reflection from geological boundaries is received with precision, providing accurate information about correlation between reflection and geological cross sections. The records will be useful in formulating plans for reflection surveys for instance of the boundary between the Osaka group and Kobe group. Generally speaking, reflection coefficients are large when the reflection is from a boundary where difference is great in elastic wave impedance (mainly difference in velocity). In the case of the boundary between the Kobe group and granite in Awaji Island, however, no strong reflection is found despite the great difference in velocity. This is attributed to the complicated, sharp inclination of the basement rock and to its weathering. 4 refs., 8 figs.

  4. Simulation model of a solar collector with a heat capacitance on TRNSYS; TRNSYS wo mochiita netsuyoryo wo motsu heibangata shunetsuki no model ka

    Yoshinaga, M. [Nagoya City University, Nagoya (Japan); Okumiya, M. [Nagoya University, Nagoya (Japan)


    A flat plate type heat collector considering a heat capacitance was structured; assembled into a solar system simulation program, TRNSYS; correction was made on this model for permeation and absorption rates as a result of incident angles onto the heat collecting surface on which sunlight reaches directly; and effectiveness of the proposed model was verified from comparing the heat collection amount with that of conventional systems and measured values. The heat collection amount decreased when incident angles of insolation are taken into consideration, and the amount approached the measured value in the case of the system with a heat capacitance. Variation in temperature at the heat collector exit decreased when the heat capacitance was taken into account. With the case of having no heat capacitance, heat collecting amount greater than the actually collected amount was calculated for days with great insolation, and less amount was calculate for smaller insolation. However, the value as a whole has become close to the measured value, though slightly greater. A value still closer to the measurements was obtained when the incident angle is considered. As seen in a seven-day average, a model having no heat capacitance and not considering the incident angle had an error from the measured value of 38.6%, while a model having a heat capacitance and considering the incident angle had an error of 9.9%. 5 refs., 7 figs.

  5. Aliasing characteristics of tau-P transform and is application to signal and noise separation; Tau-P henkan no aliasing tokusei to hakei iji wo koryoshita S/N bunri

    Kawabuchi, H.; Rokugawa, S.; Matsushima, J.; Ichie, Y. [The University of Tokyo, Tokyo (Japan); Minegishi, M.; Tsuburaya, Y. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center


    With respect to the tau-P transform method as a signal and noise (S/N) separation technology used in seismic exploration using the reflection method, a discussion has been given on conditions for the post S/N separation by the tau-P transform to function more effectively. Averaging the energy in performing the tau-P transform makes the wave energy scatter to a certain range. As a result, an aliasing phenomenon appears, in which noise is superimposed on the post-processing record. As a result of the discussion, it was verified that satisfying the two equations of G. Turner is effective in order to reduce the aliasing and maintain the relative amplitude. However, in actual calculation accuracy, waveform change was recognized to some extent, particularly amplification of events in low frequencies, and low restorability in higher frequencies. It was also observed that a method to give the tau-P region a two-dimensional Fourier transform and perform the same processing as an f-k filter can remove aliasing more simply and effectively than the HVF, and improve the S/N ratio maintaining the amplitude at the current level. 5 refs., 13 figs.

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

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


    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.

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

    Danping Wang


    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.

  8. Advanced arc-welding robot with laser sensor technology and its application field; Laser sensor wo mochiita yosetsu robot no seigyo gijutsu no kaihatsu to tekiyo

    Kugai, K.; Izawa, A. [Daihen Corporation, Osaka (Japan); Muto, S.; Mori, T. [NTT Fanet Systems Corp., Tokyo (Japan)


    A welding robot with a laser vision sensor was developed. The sensor used in this welding robot consists of a sensor head, a sensor controller, and a profile control board. The sensor controller calculates shapes of welding lines in the reference coordinates of a robot by processing different measurements, and the control board calculates them by using two-dimensional cross section information measured by the sensor. Distance from the sensor to the measurement point is measured as a result of the spot light injected from the sensor head being diffused and reflected on groove surface, part of which is collected to form an image. In addition, cross section shape of the groove is measured by giving the mirror a reciprocal arc movement in a direction perpendicular to the groove to move the mirror over the measurements points while making measurement. Influence of the arc light can be reduced by making the laser light flash sufficiently quicker than the changing speed of flashing of the arc light, and by removing information available when the light is cancelled from information available when it is lit. Extraction of points from an image as the sensor`s technological feature is performed by using the relationship between edge points and intersecting points in partial curve approximation. 10 figs., 1 tab.

  9. Fission track dating using sphene. ; Example of the Hanawa pluton. Sphene wo mochiita fission track ho ni yoru nendai sokutei. ; Hanawa shinsei gantai no rei

    Ohira, H. (Niigata University, Niigata (Japan)); Honda, T. (Musashi Institute of Technology, Tokyo (Japan). Atomic Energy Research Laboratory)


    As for the Hanawa pluton which distributes near the boundary between Fukushima and Ibaraki Prefectures, the fission track (FT) dating was conducted by using sphene. The inside surfaces of the polished samples of sphene crystal were stuck by outside detectors and the grain-by-grain method was used to determine the age by the calibration method where a Mount Dromedary Complex sphene was used as the age standard sample. The spontaneous track density differed greatly from a sample to another sample, and even in the same sample the number of crystal grains which could be the measuring subject was limited. The FT ages determined on 5 samples were 67.4Ma for mylonite-like subfacies, 91.9 Ma and 92.5Ma for large shpene bearing subfacies, and 92.5 Ma and 93.1 Ma for fine grained quartz diorite-tonalite. Furthermore, the effect of ratio of Th content to U content on the measured age was also studied. 24 refs., 5 figs., 3 tabs.

  10. Calculation of wave resistance by using Kochin function in the Rankine source method; Rankinsosuho ni okeru kochin kansu wo mochiita zoha teiko keisan

    Yasukawa, H. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)


    In order to avoid negative wave resistance (which is physically incomprehensible) generated in calculating wave resistance by using the Rankine source method, a proposal was made on a wave resistance calculation method using the Kochin function which describes behavior of speed potential in regions far apart from a hull. The Baba`s condition was used as a free surface condition for the speed potential which expresses wave motions around a hull. This has allowed a new Kochin function which uses as unknown the speed potential on the hull surface and the free surface near the hull to be defined and combined with the Rankine source method. A comparison was made between the calculated values for wave resistance, hull subsidence and trim change of an ore transporting vessel (SR107 type of ship) in a fully loaded condition and the result of water tank tests. The wave resistance values derived from pressure integration have all become negative when the Froude number is from 0.1 to 0.2, while no negative resistance has appeared in the calculations by using the Kochin function, but the result has agreed with that of the water tank tests. Accuracy of the calculations at low speeds was improved. The trim change in the calculations was slightly smaller than that in the water tank tests. The subsidence showed a good agreement. 7 refs., 1 fig.

  11. 3D-image theater system using TLP770J LCD data projector; Ekisho data projector wo mochiita rittai eizo theater system

    Kawasato, H. [Toshiba Corp., Tokyo (Japan)


    In today's multimedia era, visual systems are widely used not only for two-dimensional images but also for the depiction of virtual reality and for simulated three-dimensional images. At the same time, the projection technology used in large-screen projectors is shifting from the cathode ray tube (CRT) to the liquid crystal display (LCD). Toshiba has developed a simplified 3D-image theater system using the TLP770J LCD data projector, which offers easy maintenance and lower costs. (author)

  12. Development of new peptide synthetic method of enzyme using the extraction reactivity; Chushutsu hanno wo mochiita shiki pepuchido koso goseiho no kaihatsu

    Hirata, Makoto [Oita University, Oita (Japan)


    Recently, taste and bioactivation of large number of oligopeptide become clear, and the development of the efficient synthetic method becomes the urgency. In the production process by conventional enzyme reaction which combined the crystallization, because the solubility of the product to the water which is reaction solvent is low, the yield remained at about 60%, and the problem of reaction inhibition of the product by the crystal had also been indicated. In the enzyme synthesis of the aspartame in which he is the representative oligopeptide, it aimed at the establishment of the new synthesis method which can improve yield and reaction rate, while the segregation enzyme was continuously utilized. In this synthetic method, supply of organic solvent which dissolved the substrate, extraction of the substrate from organic solvent to water phase, synthesis reaction by the segregation enzyme in water phase, extraction of the aspartame which is a product from water phase to organic solvent progress, and they continuously progress by one complete mixing reactor. The process which controlled these speeds and yields was quantitatively analyzed, and material balance style considering substrate, enzyme and mass transfer of the product and enzyme reaction speed was deduced. The optimum operating condition for improving yield and productivity of the purpose product using this solution was examined, and optimum supply concentration and agitation speed of aspartic acid which was a substrate were started, and the optimum operating condition which realizes the improvement in high yield and productivity over 90% of the aspartame was clarified. Like this, it is that this research adopts features of liquid Citrus nobilis two-phase partition for the enzyme synthesis of the aspartame, and it is considered that there is a value, because it is the creative research which verified that the productivity can be greatly improved by the utilization of the chemical-engineering technique, and because the industrial contribution is also big. (translated by NEDO)

  13. Application of thermoelectric generator for automobile. Application of thermoelectric generation technology using Seebeck effect; Jidosha haikinetsu hatsuden. Seebeck soshi wo mochiita netsuden hatsuden gijutsu no oyo

    Shinohara, K.; Kobayashi, M.; Kushibiki, K.; Furuya, K. [Nissan Motor Co. Ltd., Tokyo (Japan)


    Study was made on energy saving by waste heat power generation for automobiles. In a waste heat generation system for automobiles, exhaust gas is converted into electric energy by a thermoelectric generator through an exhaust pipe and catalyst, and supplied to a battery or electric devices through a voltage control system. The thermoelectric generator is composed of a generating module using a Seebeck element, a heat sink and a radiator. Although an Si-Ge system Peltier element is poor in generation efficiency, it is rich in high-temperature reliability, durability and safety. However, the maximum generation efficiency of the system is as low as 5% in a normal temperature region of exhaust gas around 500degC, and further improvement of its performance is essential. For the thermoelectric module, junction of thermoelectric material and electrodes is one of the issues. Because of high- temperature use, superior solder capable of resisting the peak temperature of the system, and diffusion pressure welding and plasma flame coating techniques are necessary. At present, fuel saving of nearly 5% is possible. 11 refs., 8 figs.

  14. Rapid production of metallurgical coke by use of a simulated moving bed reactor. Mogi idoso wo mochiita kyusoku shoon ni yoru cokes no jinsoku seizo

    Miura, K.; Hayashi, J.; Sano, N. (Kyoto University, Kyoto (Japan). Research Laboratory of CArbonaceous Resources Conversion); Hashimoto, K. (Kyoto University, Kyoto (Japan). Faculty of Engineering); Iwakiri, H. (Kobe Steel, Ltd., Kobe (Japan))


    An experiment to manufacture coke with rapid temperature raising was carried out using an equipment simulating a vertical moving bed coke oven. Two kinds of trial manufacturing patterns were tested: Pattern A to raise coal temperature rapidly to about 450[degree]C, which is held for about 20 minutes, and then raised again to 800[degree]C at a rate of about 5[degree]C/min, and pattern B to raise the temperature from about 300[degree]C to 800[degree]C at a rate of about 5[degree]C/min. An experiment on test samples from heavy caking coal (PDH coal) and light caking coal (OP coal) revealed the following results: The PDH coal applied with the pattern A produced in about two hours a coke with quality equivalent to or better than practically used coke; the temperature raising pattern B resulted in no full lump formation even with the PDH coal; according to the temperature raising pattern A, manufacturing coke from the OP coal is impossible; however, if the PDH coal or pitch is mixed with the OP coal, coke may be manufactured. 6 refs., 11 figs., 2 tabs.

  15. High resolution seismic refraction method with multichannel digital data acquisition system; Digital ta channel sokutei system wo mochiita koseido kussetsuho jishin tansa

    Hayashi, K. [Oyo Corp., Tokyo (Japan)


    This paper introduces a multichannel digital data acquisition system and examples of measurements with the system in seismic exploration using the high resolution seismic refraction method. The high resolution seismic refraction system performs analyses nearly automatically by using a computer after initial travel time has been read. Therefore, the system requires high-accuracy travel time data, for which a multichannel digital measuring instrument developed recently for seismic exploration using the refraction method has been used for the measurement. The specification specifies the number of channels at 144 as a maximum, a sampling time of 62.5 {mu}sec to 4 m sec, the maximum number of sampling of 80,000 samples, and gain accuracy of {plus_minus} 1%. The system was used for surveying a tunnel having a maximum soil cover of about 800 m. The traverse line length is about 6 km, the distance between vibration receiving points is 50 m, and the number of vibration receiving points is 194. Executing measurements of single point system using GPS can derive accurate velocity in the vicinity of the basic face of the tunnel construction. Results were obtained from the investigation, which can serve more for actual construction work. 10 refs., 6 figs., 1 tab.

  16. Laboratory study on streaming potential for exploring underground water flow; Shitsunai jikken ni yoru ryudo den`i wo mochiita mizu michi tansa no kanosei no kento

    Sato, H.; Shima, H. [Oyo Corp., Tokyo (Japan)


    To investigate a possibility of exploration of underground water flow as well as to grasp the underground fluid flow by measuring streaming potential at the ground surface, some experiments were conducted using a model unit by considering the difference of permeability. For this experimental unit, water is driven by adding head difference between the polyethylene vessel filled with water and the experimental water tank. The size of water tank is 350{times}160 mm with a height of 160 mm. Twenty platinum electrodes are set on the cover of water tank. Toyoura standard sand and Kanto loam were used for the experiments. For the experiments, fluid was injected in various combined models by considering the permeability, to measure the streaming potential. As a result, it was explained by the streaming potential that the fluid flows in a form of laminar flow in the experimental water tank, and that the movement of fluid in the Kanto loam is quite slow. It was also confirmed that the streaming potential method is an effective technique for grasping the movement of fluid. 3 refs., 8 figs.

  17. Static shift correction of MT data in Tohoku district using TEM soundings; TEM ho data wo mochiita Tohoku chiho MT ho data no statistic shift hosei

    Kawakami, N.; Kumekawa, Y.; Miura, Y.; Takasugi, S. [GERD Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan); Fujinawa, Y. [National Research Institute for Disaster Prevention, Tsukuba (Japan)


    There is a possibility that the wide-band MT observation data obtained in the central part of Tohoku district include the static shift effect. To grasp the static shift effect in the MT data, the TEM soundings were conducted at all the site where the MT data were measured. The TEM sounding system was developed for the shallow survey depth ranging from 5 m to 150 m. When showing the measured results on the histogram, it was found that the static shifts were concentrated in the vicinity of zero. About 70% of the data was below 0.2 decade. Only a slight static shift effect was observed. This means that the results obtained by the two-dimensional analysis are plausible. Especially, the static shift around plain was small. Therefore, the current results around the plain were trustful. On the other hand, the static shift in the mountainous area was rather large. Accordingly, the results around the mountainous area should be carefully treated. 7 refs., 10 figs.

  18. Fundamental study of interpretation technique for 3-D magnetotelluric data using neural networks; Neural network wo mochiita sanjigen MT ho data kaishaku gijutsu no kisoteki kenkyu

    Kobayashi, T.; Fukuoka, K.; Shima, H. [Oyo Corp., Tokyo (Japan); Mogi, T. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Spichak, V.


    The research and development have been conducted to apply neural networks to interpretation technique for 3-D MT data. In this study, a data base of various data was made from the numerical modeling of 3-D fault model, and the data base management system was constructed. In addition, an unsupervised neural network for treating noise and a supervised neural network for estimating fault parameters such as dip, strike and specific resistance were made, and a basic neural network system was constructed. As a result of the application to the various data, basically sufficient performance for estimating the fault parameters was confirmed. Thus, the optimum MT data for this system were selected. In future, it is necessary to investigate the optimum model and the number of models for learning these neural networks. 3 refs., 5 figs., 2 tabs.

  19. Analogue experiment of the crustal deformation by X-ray CT; X sen CT wo mochiita chikaku no henkei no analogue jikken

    Nakajima, Y.; Shi, B; Murakami, Y. [Geological Survey of Japan, Tsukuba (Japan)


    This paper reports a predictive result on a deformation experiment on sand beds using an X-ray computerized tomography (CT) equipment. The X-ray CT is a method to perform the following processes: X-rays are irradiated on a sample; decayed intensity data are measured along ray paths of the permeated X-rays; the data are inverted by using the Fourier transform; and spatial distribution of the coefficient of X-ray absorption inside the sample is acquired as a gray scale image. The deformation experiment was carried by putting sand into an acrylic container to a depth of 2 cm and manually pressing a plate in the horizontal direction. Sand blocks make a relative motion along a specific plane when they are deformed, but it was not possible to recognize faults clearly by naked eyes. Upon completion of the deformation, the experimental device was placed on the CT equipment to acquire images of the two-dimensional cross section. The higher the X-ray absorption coefficient, the brighter the picture elements. It can be seen that three inversed faults have been imaged clearly. Therefore, this equipment was verified usable as an effective observation equipment for an analogue deformation experiment. 4 refs., 2 figs.

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

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


    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.

  1. Development of spherical fine powders by high-pressure water atomization using swirl water jet; Senkaisui jet wo mochiita koatsusui atomize ni yoru kyujo bifun no kaihatsu

    Kikukawa, M.; Matsumoto, S.; Inaba, T.; Iwatsu, O.; Takeda, T. [Fukuda Metal Foil and Powder Co. Ltd., Kyoto (Japan)


    In order to obtain spherical fine powders, a new high-pressure water atomization method using swirl water jet was developed. In this paper the effects of jet swirl angle ({omega}) upon the properties of powders were investigated. Cu-10 mass%Sn alloy was atomized by this method at the constant water pressure of 83.3 MPa and constant metal orifice diameter of 4mm, while {omega} was varied from 0 to 0.18 rad. Median diameter of the powder by the laser diffraction method (D{sub 50}) decreased from 12.5 {mu}m to 7.5{mu}m with increasing {omega}, and this corresponded to Fisher average diameter (D{sub FS}) at about w=0.18 rad. The apparent and tap density of the powder increased about 1 and 1.5 Mg/m{sup 3} respectively, and the particle shape observed by SEM became spherical with increasing {omega}. (author)

  2. Model construction for quality of beer and brewing process using FNN; FNN wo mochiita biru hinshitsu to jozo kotei no moderuka

    Noguchi, H.; Hanai, T.; Takahashi, W.; Honda, H.; Kobayashi, T. [Nagoya Univ., Nagoya (Japan). Dept. of Biotechnology; Ichii, T.; Tanikawa, M.; Masuoka, S. [KIRIN Brewery Corp., Tokyo (Japan). Research Laboratory for New Product


    Models for sensory evaluation of beer and the beer brewing process were constructed using a fuzzy neural network (FNN). A new method for optimal model selection using a genetic algorithm and a SWEEP operator method was compared with a conventional method using the parameter increasing method. As the result, the new method was useful for the optimal model selection by simplifying the model structure, improving the reliability of fuzzy rules, and accelerating the calculation speed (about 10 times as fast as conventional method) for constructing the model with high accuracy. The percentage of correct answers of the sensory evaluation model is 92 %. The important variables are selected as the input variables, and the obtained fuzzy rules in modeling coincide well with knowledge data bases acquired by process operators, and it is proven that the obtained FNN models are adequate. (author)

  3. Solubilization of lignite and behavior of oxygen containing functional groups in coal with superacid; Chokyosan wo mochiita kattan no kayoka oyobi sanso kannoki no kyodo

    Shimizu, K.; Saito, I. [National Institute for Resources and Environment, Tsukuba (Japan); Sasaki, S.; Suganuma, A. [Science University of Tokyo, Tokyo (Japan). Faculty of Science and Technology


    Solubilization of lignite including a large amount of oxygen containing functional groups was attempted using HF/BF3, and the behavior of oxygen containing functional group, one of the important factors for coal liquefaction, was studied. In experiment, the cooled slurry of Yallourn coal specimen and solvent (toluene, isopentane) was filled into a vacuum autoclave together with HF/BF3. Reaction was performed under spontaneous pressure at 50, 100 or 150{degree}C for 3 hours. The distribution of oxygen containing functional groups in each coal specimen was determined by quantification of carboxyl group, hydroxyl group and carbonyl group. As the experimental result, the superacid mixture of HF and BF3 considerably improved the solubility of coal specimens into solvent as compared with individual HF and BF3. The solubility was 68wt% into benzene, 96% into THF and 99% (nearly 100%) into pyridine. It was suggested that production of Broensted acid with strong acidity causes strong catalysis. 6 refs., 2 figs., 1 tab.

  4. Estimation of hydrogen bondings in coal utilizing FTir and differential scanning calorimetry (DSC); FTir to DSC wo mochiita sekitannai suiso ketsugo no teiryoteki hyoka no kokoromi

    Mae, K.; Miura, K. [Kyoto University, Kyoto (Japan). Faculty of Engineering


    With an objective to know coal condensation structure which has influence on coal conversion reaction, an attempt was made on quantitative evaluation of hydrogen bonding in coal. Using as test samples the VDC made from Taiheiyo coal swollen by tetralin and vacuum-dried, and its pyrolyzed char, DSC measurement and Fourier transform infrared spectroscopy (FT) were performed. An FT spectrum comparison revealed that the VDC swollen at 220{degree}C has the hydrogen bonding relaxed partly from the original coal. However, since the change is in a huge coal molecular structure restraining space, it has stopped at relaxation of the bonding energy without causing separation as far as free radicals. On the other hand, the DSC curve shows that the VDC has slower endothermic velocity than the original coal. In other words, the difference in heat absorption amounts in both materials is equivalent to the difference of enthalpy ({Delta} H) of both materials, which corresponds to the relaxation of the hydrogen bonding. Therefore, the {Delta} H was related to wavenumber shift of the FT spectra (which corresponds to change in the hydrogen bonding condition). By using this relationship, a method for evaluating hydrogen bonding distribution was proposed from an O-H contracting vibration change that can be measured by using the FT spectra and a thermal change that can be measured by using the DSC. 3 refs., 7 figs.

  5. Development of liquefaction process of coal and biomass in supercritical water; Chorinkaisui wo mochiita sekitan biomass doji ekika process no kaihatsu

    Nonaka, H.; Matsumura, Y.; Tsutsumi, A.; Yoshida, K. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Masuno, Y.; Inaba, A. [National Institute for Resources and Environment, Tsukuba (Japan)


    Liquefaction of coal and biomass in supercritical water has been investigated, in which strong solubilization force of supercritical water against hydrocarbons is utilized. Free radicals are formed through the cleavage of covalent bonds in coal under the heating condition at around 400{degree}C during coal liquefaction. It is important to stabilize these unstable intermediate products by hydrogen transfer. On the other hand, hydrogen is not required for the liquefaction of biomass having higher H/C atomic ratio and oxygen content than those of coal. Co-liquefaction of coal and biomass was conducted using supercritical water, in which excess hydrogen from the liquefaction of biomass would be transferred to coal, resulting in the effective liquefaction of coal. Mixture of coal and cellulose was liquefied in supercritical water at 390{degree}C under the pressure of 25 MPa using a semi-continuous reactor, and the results were compared with those from the separate liquefaction of them. The co-liquefaction of coal and cellulose did not show any difference in the residue yield from the separate liquefaction of these, but led to the increased production of compounds with lower molecular weight. The liquefaction was completed in 15 minutes. 5 refs., 3 figs., 3 tabs.

  6. H{infinity} control with exact linearization for AC drive system with CSI; Genmitsuna senkeika wo mochiita denryugata inverter kudo yudo dendokikei no H{infinity} seigyo

    Bai, Z.; Ide, K.; Yong, Z.; Tsuji, T. [Kyushu Institute of Technology, Kitakyushu (Japan)


    This paper reports the following method for controlling the vector of a current system inverter driven induction motor. The method deals with parameter variation in the control object and modeling error by using the H{infinity} control on its approximated linear model (in the vicinity of the equilibrium point), and handles disturbances including load variation by broadening the effective region in the linear model via close linearization of the state space. The paper explains specifically a design of a speed controller through modeling the control system of the induction motor including the current system inverter (connected to a converter), close linearization of the resultant nonlinear model (using rotation angle speed of the induction motor and DC link current as the state vectors, and using the output voltage of the converter as a scaler input), and application of the H{infinity} theory. In addition, the paper presents the result of an experiment that verified good control performance of the designed controller. 11 refs., 8 figs., 1 tab.

  7. Numerical analysis of the flow in a poppet valve using a streamline coordinate system; Ryusen zahyo wo mochiita pet bennai no nagare no suchi kaiseki

    Yu, K.; Takahashi, K.; Nonoshita, T.; Ikeo, S. [Sophia Univ., Tokyo (Japan)


    The present paper describes the numerical analysis of the flow through a poppet valve by a streamline-coordinate system. Using this system, poppet valves with various shapes can easily be analysed, because a streamline along a solid wall or a free surface can be chosen as a coordinate. Parameters used in this analysis are poppet shape (cone angle for conical type and radius for spherical type), seat chamfer width, seat chamfer angle, valve lift and flow rate. Discharge coefficients and flow forces acting on poppets were analysed in detail, The computed results were in good agreement with the experimental ones. The conclusions are as follows: The flow forces on the poppet decrease with an increase in valve lift; The flow force on the conical poppet with a sharp edge seat is larger than that with a chamfered seat; The flow force is almost independent of flow rate for sharp edge seat, but strongly dependent for chamfered seat. (author)

  8. Real-time realization of scale detection based on comb filters using DSPs; Kushigata filter ni motozuku DSP wo mochiita real time onkai kenshutsu

    Saito, T.; Matsui, T. [Toyota National College of Technology, Aichi (Japan); Honda, H.; Tadokoro, Y. [Toyohashi Univ. of Technology (Japan)


    Transcription is an operation to collect a music from tones played by a music instrument. It is not easy for a person to collect the music correctly as special knowledge and experience are necessary. Therefore, studies on an automatic transcription by a computer are being conducted now. In this paper, a scale detection method eliminating multiple frequencies by a comb filter is proposed. The characteristics of this system are as follows. It samples corresponding to the music scale, using the differences of sampling points to estimate the music scale. And, owing to use of the comb filter, it is a scale detection method without influences of multiple frequencies composed in the tones played by a music instrument. This paper describes the realization of the comb filter by over sampling and its application onto a harmony detection. Based on this scale detection method, a real time scale detection method using DSPs may be realized and scale detection applicable to real scale of a key board may be possible. 10 refs., 14 figs., 1 tab.

  9. Evaluation of the force rum flotation result by the ion exchange using the rubidium; Rubijiumu wo mochiita ion kokan ni yoru karamu fusen kekka no hyoka

    Kamiyama, Jun' ichi [Osaka University, Osaka (Japan); Fujimoto, Hidekazu; Matsukata, Masahiko


    The following are contained: Hydroxyl group and carbonyl, functional oxygen group and mineral like the carboxyl group in which the coal is the hydrophilic component. The column flotation result is greatly different, since existence proportion of these components is different by the coal type. We regarded it as whether it could not simply evaluate the force rum flotation result of the coal at area proportion of the syneresis site on the coal particle exterior. In this study, the force rum flotation was carried out using balance wheel (bituminous coal), mountain west (anthracite), bituminous coal, and Illinois (lignit) charcoal it is almost same (bituminous coal). The ladder of carbon material recovery rate was the balance wheel > Kawanishi > almost same > Illinois charcoal. Next, area proportion ({alpha}{sub ex-OH}, {alpha}{sub in-OH} respectively) of the hydrophilic site in coal particle exterior and particle inside {alpha}{sub ex-OH} was obtained. In case of the almost same charcoal, was bigger than {alpha}{sub in-OH}. It seems to slightly oxidize the particle surface the almost same charcoal. In 3 kinds of bituminous coal, the ladder of carbon material recovery rate and {alpha}{sub in-OH} agreed. However, it is necessary to consider not only area proportion but also wettability of the hydrophobic site of the hydrophilic site for the planktonic of mountain west charcoal which is the anthracite. (translated by NEDO)

  10. Toxicity evaluation of chlorinated organic compounds using immortalized rat hepatocytes; Fushika rat kansaibo wo mochiita yuki enso kagobutsu no dokusei hyoka no kokoromi

    Sone, H.; Nakajima, M.; Yonemoto, J. [National Institute for Environmental Studies, Tsukuba (Japan)


    Chlorinated organic compounds has high priority for toxicity screening among environmental hazardous chemicals. In the present study, we used immortalized rat hepatocytes as a liver model in vitro to evaluate the toxicity of nine chlorinated organic compounds. Toxicity of nine chlorinated organic compounds were evaluated to cellular viability of immortalized rat hapatocytes. The potency of the toxicity based on 50% inhibitory concentration (IC50) value was in the following order: triclocalban>triclosan>3,4-dichloroaniline>2,5-diclorophenol> 2,5-dichloroanisole>p-dichlorobenzene> p-chloroaniline>o-dichlorobenzene=tris (2-chloroethyl) phosphate. The rank order of cytotoxic potency of nine chemicals was compared with toxicity information using animals. The rank order of cytotoxic potency did not relative to the order referenced mean lethal dose (LD50) as an index of acute toxicity of rats or mice. However, the rank order of cytotoxic potency relatively correlated non-observed adverse effect level (NOAEL) under the exposure duration adjusted for chronic toxicity in vivo. These data suggests that the origin of testing cell had better to make match target organ of toxic chemicals for extrapolation from data of bioassay in vitro to in vivo. 16 refs., 2 figs., 3 tabs.

  11. Improvement of combustion in a direct injection diesel engine by micro-hole nozzle; Micro hole nozzle wo mochiita chokusetsu funshashiki diesel kikan no nensho kaizen

    Murata, M. [Keio University, Tokyo (Japan); Kobori, S. [Tokyo Institute of Technology, Tokyo (Japan); Iida, N. [Keio University, Tokyo (Japan). Faculty of Science and Technology


    In an attempt to promote the atomization of fuel spray and the mixing of fuel and air in diesel engines, a micro-hole nozzle which has orifices with a diameter smaller than 0.10mm was developed. In this study, the combustion tests were carried out using a single cylinder diesel engine equipped with a micro-hole nozzle and a common rail type high-pressure fuel injection system. A comparison with the results of a conventional nozzle experiment showed that the peak of initial premixed combustion increased, but the peak of diffusion combustion decreased. As a result, when nozzle orifice diameter become small from {phi} 0.15 mm to {phi} 0.10 mm, the combustion was accompanied by smokeless with the same levels of NO{sub x} emission and fuel economy. And results of a comparison the toroidal type chamber with the shallow dish type chamber revealed that the optimization of combustion chamber is necessary for the increase of the injection stage with increasing of the number of nozzle orifice. If an orifice diameter becomes {phi} 0.06 mm, the diffusion combustion can not be observed and the combustion is formed of only premixed combustion. The combustion in the case of {phi} 0.06 mm was accompanied with the drastic deterioration of fuel economy, smoke and HC with all over load. But the micro-hole nozzle has a potential for the formation of the lean and homogeneous premixed mixture until the fuel-air mixture ignites. (author)

  12. Emission behavior of OH radical in internal EGR using a 2-cycle engine; 2 cycle engine wo mochiita naibu EGR no OH radical no hakko kyodo

    Hashimoto, S.; Amino, Y.; Yoshida, K.; Shoji, H.; Saima, A. [Nihon University, Tokyo (Japan)


    The purpose of this study was to examine and consider the influence, which the remained gas exercised on combustion. 2-cycle engine was Used as the test engine. Internal EGR was run. The means was that the test engine was fitted the back pressure control plate on the exhaust port. The conditions, which were run with internal EGR and without internal EGR, were compared. The OH radical, which plays important role in combustion of hydrocarbon fuels, was measured with emission spectroscopy. In internal EGR, the unburned end gas on exhaust port side was susceptible to the remained gas. 6 refs., 8 figs., 1 tab.

  13. Power system stabilizing control by superconducting magnetic energy storage using neural network; Newral network wo mochiita chodendo energy chozo sochi ni yoru keito anteika seigyo

    Osawa, Y.; Kanemitsu, T.; Kawakami, T.; Shintaku, M.; Arai, K. [Kobe University, Kobe (Japan)


    In order to solve the difficulty of realizing power system stabilization using non-linear optimal control, this paper discusses a power system stabilization control by superconducting magnetic energy storage (SMES) using a neural network. This system consists of a kind of feedback control system that derives an optimal stabilizing control on various initial system operating conditions and failure conditions applied with the maximum principles, and learns the best stabilization using the control as tutorial signals and using the neural network. The object model system is a one-unit infinite busbar system, whose generator terminal is installed with the SMES. With respect to the system learning using the neural network, the network output to the learned failure patterns has agreed with the tutorial signals nearly completely. As a result of simulating example systems, it was confirmed that the operating conditions within a reasonable range and failure conditions were learned well, control effects close to the optimal control were shown, and the oscillation suppressing effect of the SMES can be utilized effectively. 11 refs., 13 figs., 4 tabs.

  14. Three-dimensional mise-a-la-masse modeling using horizontal well; Suihei kosei wo mochiita ryuden den`iho no sanjigen modeling

    Mizunaga, H.; Ushijima, K.; Hashimoto, K.; Masuda, K. [Kyushu University, Fukuoka (Japan). Faculty of Engineering


    The 3-D model program was developed to apply a mise-a-la-masse method to linear current sources with optional shapes. Mise-a-la-masse method is a bipolar mapping survey method using current sources installed in wells, and recently has been widely used for direct exploration of geothermal reservoirs. This method is also used for monitoring underground fluid as electrode arrangement of fluid flow tomography for surveying underground fluid (geothermal fluid, underground water, petroleum). In the geothermal reservoir exploration, the casing pipes of wells are used as linear current sources, and measured data are processed as those based on vertical current source. In the largely inclined well, the inclination of current sources should be considered. The 3-D modeling program was developed by difference calculus using the theoretical potential equation and apparent resistivity based on linear current sources with optional 3-D shapes. The numerical model experiment result clarified that the previous theoretical equation for vertical wells is inapplicable to inclined linear current sources because of clear asymmetric apparent resistivity distribution. 6 refs., 6 figs.

  15. Study of seismic data acquisition using physical modeling system; Butsuri model jikken sochi wo mochiita data shutoku gijutsu ni kansuru kento

    Tsukui, R.; Tsuru, T. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center; Matsuoka, T [Japan Petroleum Exploration Corp., Tokyo (Japan)


    For the physical modeling system of Technology Research Center, Japan National Oil Corporation, data acquisition on the ocean and ground can be simulated using models. This system can provide data for verification of the data processing and elastic wave simulation algorithm. This can also provide data for decision of experiment specifications by making a model simulating the underground structure of the given test field. The model used for the physical modeling system is a gradient multilayer model with six-layer structure. Depth migration before stacking was conducted using data obtained through two acquisition methods, i.e., up-dip acquisition and down-dip acquisition. The depth migration before stacking was performed for data obtained by up-dip acquisition in addition to the records obtained by down-dip acquisition. Consequently, a definite reflection surface was observed, which has not been observed from the processing results of down-dip acquisition data. 9 figs.

  16. Relative amplitude preservation processing utilizing surface consistent amplitude correction. Part 3; Surface consistent amplitude correction wo mochiita sotai shinpuku hozon shori. 3

    Saeki, T. [Japan National Oil Corporation, Tokyo (Japan). Technology Research Center


    For the seismic reflection method conducted on the ground surface, generator and geophone are set on the surface. The observed waveforms are affected by the ground surface and surface layer. Therefore, it is required for discussing physical properties of the deep underground to remove the influence of surface layer, preliminarily. For the surface consistent amplitude correction, properties of the generator and geophone were removed by assuming that the observed waveforms can be expressed by equations of convolution. This is a correction method to obtain records without affected by the surface conditions. In response to analysis and correction of waveforms, wavelet conversion was examined. Using the amplitude patterns after correction, the significant signal region, noise dominant region, and surface wave dominant region would be separated each other. Since the amplitude values after correction of values in the significant signal region have only small variation, a representative value can be given. This can be used for analyzing the surface consistent amplitude correction. Efficiency of the process can be enhanced by considering the change of frequency. 3 refs., 5 figs.

  17. Study of 1D complex resistivity inversion using digital linear filter technique; Linear filter ho wo mochiita fukusohi teiko no gyakukaisekiho no kento

    Sakurai, K.; Shima, H. [OYO Corp., Tokyo (Japan)


    This paper proposes a modeling method of one-dimensional complex resistivity using linear filter technique which has been extended to the complex resistivity. In addition, a numerical test of inversion was conducted using the monitoring results, to discuss the measured frequency band. Linear filter technique is a method by which theoretical potential can be calculated for stratified structures, and it is widely used for the one-dimensional analysis of dc electrical exploration. The modeling can be carried out only using values of complex resistivity without using values of potential. In this study, a bipolar method was employed as a configuration of electrodes. The numerical test of one-dimensional complex resistivity inversion was conducted using the formulated modeling. A three-layered structure model was used as a numerical model. A multi-layer structure with a thickness of 5 m was analyzed on the basis of apparent complex resistivity calculated from the model. From the results of numerical test, it was found that both the chargeability and the time constant agreed well with those of the original model. A trade-off was observed between the chargeability and the time constant at the stage of convergence. 3 refs., 9 figs., 1 tab.

  18. Imaging of lateral heterogeneity by using reflected surface waves. Hansha hyomenha wo mochiita suihei hoko no chika kozo fukinshitsusei no kenshutsu

    Shiba, Y. (Central Research Institute of Electric Power Industry, Tokyo (Japan)); Kobayashi, Y. (Kyoto Univ., Kyoto (Japan). Faculty of Science)


    Surface wave holography was applied to the reflected surface waves obtained on the Uji ground, Kyoto University. Clear reflected surface waves were confirmed in the records of waves and it was found possible to detect the surface waves generated by an artificial hypocenter. The reflected waves consisted of two groups having different frequency zones, which were the reflected waves from two different reflectors. It is clear from this result that in the case of the reflected wave groups due to the multiple scatterers, the surface wave holography enables to determine the corresponding locations of respective scatterers. The combination of the back projection method using the reflected wave envelopes and the other method such as incident angles to the array is most effective as the analyzing method. The surface wave holography can be used sufficiently to detect the lateral heterogeneity. 17 refs., 12 figs., 4 tabs.

  19. Interactive steering of supercomputing simulation for aerodynamic noise radiated from square cylinder; Supercomputer wo mochiita steering system ni yoru kakuchu kara hoshasareru kurikion no suchi kaiseki

    Yokono, Y. [Toshiba Corp., Tokyo (Japan); Fujita, H. [Tokyo Inst. of Technology, Tokyo (Japan). Precision Engineering Lab.


    This paper describes extensive computer simulation for aerodynamic noise radiated from a square cylinder using an interactive steering supercomputing simulation system. The unsteady incompressible three-dimensional Navier-Stokes equations are solved by the finite volume method using a steering system which can visualize the numerical process during calculation and alter the numerical parameter. Using the fluctuating surface pressure of the square cylinder, the farfield sound pressure is calculated based on Lighthill-Curle`s equation. The results are compared with those of low noise wind tunnel experiments, and good agreement is observed for the peak spectrum frequency of the sound pressure level. 14 refs., 10 figs.

  20. Solar cells and thin film LED using amorphous SiC. Amorphous SiC wo mochiita taiyou denchi oyobi usumaku LED

    Hamakawa, Y. (Osaka Univ., Osaka (Japan). Faculty of Engineering Science)


    This paper introduced the photoelectric properties of amorphous SiC (a-SiC), application to highly efficient solar cells, application to wide area emitting elements such as LED (light emitting diode) and application to OEIC (optoelectronic integrated circuit) which is expected in near future. The light sensitizing effect in which photoconductivity of a-SiC:H film increases 2-3 figures by B dopping, was found. Flexible and wide area thin film LED has been able to manufacture by this discovery. In addition, highly efficient conversion rate has been able to get by the technical development such as solar cells made of a-SiC/ a-Si hetrojunction. Further, wide area sollar cells has been able to manufacture on any substrate by the development of TFLED (thin film light emitting diode). The application of TFLED made of SiC to OEIC is also investigated. 18 refs., 15 figs., 2 tabs.

  1. Thermal and aqua-reserve characteristics of an aqua-reserver using a super-absorbent polymer gel; Kokyusuisei jushi wo mochiita hosuizai no hosui netsutokusei

    Jin, Z. [Tokyo Metropolitan Univ., Tokyo (Japan); Asako, Y.; Yamaguchi, Y.; Yoshida, H. [Tokyo Metropolitan Univ., Tokyo (Japan). Faculty of Technology


    This paper describes thermal and aqua-reserve characteristics of a super-absorbent polymer gel which absorbs an aqueous solution of calcium chloride as a heat absorbent in a firewall during fire. Only gels which absorbed 10 to 40 mass% of the solutions were tested. The absorbency of the polymer and latent heat of the gel were measured using a thermal analyzer of TG/DTA. To obtain the aqua-reserve characteristics, changes in weight of the gel which was left in a room under controlled temperature was measured. Also, an equilibrium concentration of the calcium chloride solution in the gel was obtained. 8 refs., 12 figs., 3 tabs.

  2. Analysis of the pollutant in the environment using supercritical fluid chromatography (SFC); Chorinkai ryutai kuromatogurafui (SFC) wo mochiita kankyo chu no osen busshitsu no bunseki

    Kakuchi, T.; Miura, Y. [Hokkaido Univ., Hokkaido (Japan)


    The analysis of the organic pollutant in the environment is carried out as the following procedure; the organic substance is extracted by using the organic solvent from a collected sample, an instrument analysis such as gas chromatography (GC) or high performance liquid chromatography (HPLC) are done after the clean up the sample by column chromatography. The analysis using supercritical fluid instead of the organic solvent in each stage is supercritical fluid extraction (SFE) or supercritical fluid chromatography (SFC). The supercritical fluid has a density and viscosity coefficient between gas and liquid, and the control of the dissolving power is possible by the change of temperature and pressure. Therefore, it has the advantage as follows: The material mobile speed is high and separation and extraction are rapid; It is easy to adjust the dissolving power and possible to carry out selective separation and extraction; The removal of solvent can be easily carried out since supercritical CO{sub 2} used is a gas in the normal pressure. In this paper, the analytical instrument in which the extraction is carried out in organic solvent and clean up was done in SFC was introduced. (NEDO)

  3. Measurement of local strain-induced martensitic phase transformation by micro-hardness; Bisho kodo wo mochiita kyokusho hizumi yuki martensite hentai tokusei no sokutei

    Shibutani, Y.; Taniyama, A.; Tomita, Y.; Adachi, T. [Kobe University, Kobe (Japan). Faculty of Engineering


    By the duplex effect produced by two kinds of phases of austenite and martensite, the transformation-induced plasticity (TRIP) steel is improved in ductility and fracture toughness. The strain-induced martensitic phase transformation could be associated with the strain localization behavior. Accordingly, the measurement of the amount of local transformation is necessary in order to construct a more physical evolution model in the constitutive equation. In this study, a new measurement system using a micro-hardness tester is proposed to obtain a volume fraction map of the martensitic phase expanding in the neighbor of strain localization. Then the system is applied to investigate the inhomogenous transformation behavior around the notch root of SUS 304 stainless steel bar under uniaxial tension. 27 refs., 11 figs., 1 tab.

  4. Improvement of prediction accuracy of large eddy simulation on colocated grids; Colocation koshi wo mochiita LES no keisan seido kaizen ni kansuru ichikosatsu

    Inagaki, M.; Abe, K. [Toyota Central Research and Development Labs., Inc., Aichi (Japan)


    With the recent advances in computers, large eddy simulation (LES) has become applicable to engineering prediction. However, most cases of the engineering applications need to use the nonorthgonal curvilimear coordinate systems. The staggered grids, usually used in LES in the orthgonal coordinates, don`t keep conservative properties in the nonorthgonal curvilinear coordinates. On the other hand, the colocated grids can be applied in the nonorthgonal curvilinear coordinates without losing its conservative properties, although its prediction accuracy isn`t so high as the staggered grid`s in the orthgonal coordinates especially with the coarse grids. In this research, the discretization method of the colocated grids is modified to improve its prediction accuracy. Plane channel flows are simulated on four grids of different resolution using the modified colocated grids and the original colocated grids. The results show that the modified colocated grids have higher accuracy than the original colocated grids. 17 refs., 13 figs., 1 tab.

  5. Batch process. Batch plant scheduling using an intelligent system developing tool (G2); Interijento system kaihatsu tsuru ( G2 ) wo mochiita bacchi puranto sukejuringu

    Fukuoka, H. [Itochu Technology Science Co. Ltd. (Japan)


    G2 is used in many industrial fields as a tool capable of forming in a comparatively short period of time various kinds of high-degree intelligent system including a scheduling system. This paper introduces G2, and then describes a batch scheduling system. The software techniques provided by G2 include the techniques concerning a real time system, an expert system, a graphic user interface, and object-oriented security network. G2 has a striking feature that it is a developing tool adapted to enable these software techniques to be utilized in a united environment. A program developed by G2 has a feature that it can be operated as it is without changing the source program at all even when the program is used in a machine of another OS. The paper introduces a beer production scheduling system as an actual example. 3 figs.

  6. Study of seismic data acquisition using physical modeling system; Butsuri model jikken sochi wo mochiita data shutoku gijutsu ni kansuru kento

    Tsukui, R.; Tsuru, T. [Tech. Research Center, Japan National Oil Corp., Tokyo (Japan); Matsuoka, T. [Japan Petroleum Exploration Corp., Tokyo (Japan)


    The Physical Modeling System introduced into the Technology Research Center, Japan National Oil Corporation, and data collected by use of the system are presented. The Physical Modeling System is 10,000 times smaller than the real one, comprising a water tub section, measuring device section, and control section, etc. The water tub section comprises a tub for housing the model, transducers for transmitting and receiving vibration, controllers, etc. The water tub measures 1.8{times}1.2{times}0.9m. The model used in the experiment is an `inclined multilayer model` with each of its six layers pinching out toward the top, and is usable for the comparison of various migration methods. In one case in the records, reception was made at 184 reception points deployed at intervals of 3mm, when the minimum offset was 15mm and the maximum offset 564mm. Nothing very obvious was observed when the ordinary overlapping of DMO and CDP was applied to this record, which suggests that pre-overlapping migration treatment is required. 5 figs.

  7. Proposal and study of a long-span composite cable-stayed bridge with new hybrid girder; Atarashii gosei kozo shuketa wo mochiita chodai fukugo shachokyo no kenkyu

    Yoshida, K.; Hishiki, Y.; Furuichi, K. [Kajima Corp., Tokyo (Japan)


    A hybrid or mixed structure (composite structures) are a matter of increasing concern which takes in each advantage of steel and concrete. A field of bridges is no exception, with the plan and construction carried out for the new type of composite bridge, such as a composite cable-stayed bridge and a composite extra dose bridge as a long span bridge, and a composite truss bridge and a corrugated steel plate web bridge as a medium-span bridge, with technological development becoming active in this field. In such a technological trend, a hybrid two-girder structure was devised, a structure consisting of a concrete filled steel pipe for a girder and a precast (PC) floor plate for a floor board, as the girder structure of a long-span cable-stayed bridge in the subject research; also, applicability was examined using, as an example, the composite cable-stayed bridge with hybrid girders employed for the span. This paper reports the result of the analysis of the entire system, the analysis made for the purpose of examining the characteristic and the feasibility of this hybrid girder. The analysis revealed the structural feasibility of the long-span composite cable-stayed bridge using two hybrid girders of concrete-filled steel pipes thus devised. (NEDO)

  8. Analysis of signal transduction in brain cells using molecular signal microscope; Bunshi jiho kenbikyo wo mochiita nousaibou no joho henkan kiko no kaiseki

    Kawato, Suguru [The University of Tokyo, Tokyo (Japan). Dept. of Biophysics and Life Sciences


    We analyzed the signal transduction in brain neurons by real-time imaging of Ca/NO signals using the Molecular Signal Microscope. We also analyzed synthesis and action of neurosteroids in the hippocampus. We discovered steroid synthesis machinery containing cytochrome P 450 scc in hippocampal neurons. We found that pregnenolone sulfate acutely potentiated NMDA receptor-mediated Ca conductivity in hippocampal neurons. We also found that stress steroid corticosterone acutely prolonged NMDA receptor-mediated Ca{sup 2+} influx, resulting in Ca-induced neuro-toxicity. (author)

  9. Investigation on chemical heat pump using calcium-chloride; Enka calcium no suiwa dassui hanno wo mochiita solar chemical heat pump ni kansuru kenkyu

    Fujii, I.; Arai, T.; Saito, Y. [Meiji University, Tokyo (Japan)


    With an objective of developing a room heating system utilizing a solar chemical heat pump, an experimental system was fabricated to evaluate its performance. Steam was employed as a working gas, and for a reaction material, calcium-chloride was used, which has a reaction temperature zone permitting safe use and fitting the purpose among other hydrate systems and has high standard enthalpy in hydration. Water was used as a solar heat transferring medium. The system operates under the following principle: a container I is filled with hydrated salt and a container II with water, the two containers being linked with a pipe interposed with a valve; heat is inputted and outputted by performing charging and discharging alternately; and the role of a heat pump is played by deriving from environment the heat of water evaporation in the container II during discharging. The COP must take into account the electric power consumption of the water circulation pump to transfer solar heat. A COP of 0.256 was derived as a result of the experiment. 3 refs., 5 figs.

  10. Investigation of the simulation for the solar DHW system by TRNSYS; TRNSYS ni yoru kaihogata tank wo mochiita solar kyuto system no simulation chosa

    Oishi, M.; Noguchi, T. [Japan Quality Assurance Organization, Tokyo (Japan); Okumiya, M. [Nagoya University, Nagoya (Japan)


    With an objective of establishing a method for evaluating performance of a photovoltaic hot water supply system, a discussion was given on utilization of the simulation program, TRANSYS. The discussion was addressed on a photovoltaic hot water supply system of forcible circulation type using commercially available open-type heat storage tanks. An experiment was performed as an indoor test using an artificial solar light source. The TRANSYS makes available a type 04 which handles each node as a complete mixture by fixing and dividing the heat storage tank, and a type 38 which expresses heat transfer between temperature layers by means of piston flow as a heat transfer coefficient. Both types were subjected to calculation. The result of the discussion may be summarized as follows: both types provided values close to the experimental values of quantity of heat derived by utilizing solar heat; however, with the type 04, heat transfer cannot be modeled if the system is left still with temperature difference in the heat storage tank being large; and with the type 38, modeling is possible when the system is left still with temperature difference in the heat storage tank being large, but temperature gradient is difficult to be modeled during heat collection and when hot water is supplied. 1 ref., 7 figs., 5 tabs.

  11. On-line monitoring system of lactic acid fermentation by using integrated enzyme sons ors; Shusekika koso sensa wo mochiita nyusan hakko keisokuyo onrain monitaringu shisutemu

    Suzuki, Masayasu; Kumagi, Takeshi; Nakashima, Yuuichi [Kyushu University, Fukuoka (Japan). Dept. of Biochemical Engineering and Science


    An on-line monitoring system for lactic acid fermentation is developed by using integrated micro enzyme sensors, a flow injection analysis system, and a micro dialysis system. The calibration curves of micro glucose, lactose and lactate sensors show good linearity in the concentration range below 70 mM. By combination with the micro dialysis system, the enzyme sensors can measure the whole concentration range of lactic acid fermentation, and interference by the medium can not be observed. The on-line sensor system is then applied to lactic acid fermentation of Lactobacillus delbrueckii. The sensor system can monitor the glucose and lactate concentrations simultaneously during 24-h fermentation, and the measurements show good agreement with those of the conventional colorimetric method. The sensor system can also be applied to on-line monitoring of lactose and lactate during Lactobacillus lactis fermentation. (author)

  12. Monitoring on-line system for the lactic fermentation measurement using the integration enzyme sensor; Shusekika koso sensa wo mochiita nyusan hakko keisokuyo onrain monitringu shisutemu

    Suzuki, Masayasu; Kumagaya, Tsuyoshi; Nakajima, Yoichi [Kyushu Institute of Technology, Fukuoka (Japan)


    The monitoring on-line system for the lactic fermentation measurement in which the simultaneous measurement of the substrate. Generation was possible was constructed without consuming the culture medium by using soliciting small enzyme sensor and flow injection analysis system integrate. There was the linearity that anyway was also range of concentration of 70mM or less and that it is good on the calibration curve of minute glucose, lactose, and lactic acid sensor. It became clear that it proved that all range of concentration of the substrate of these three which combining with the micro diary system, breaks in the lactic fermentation measurement with the necessity can be measured and not observe the interference by medium components, etc. either. Constructed monitoring on-line system is Lactobacillus delbrueckii and, it was applied to the lactic fermentation process of Lactobacillus lactis. Through the fermentation process for 24 hours, simultaneous measurement of glucose (or lactose) and lactic acid is possible. The measured value agreed well with the result of colorimetric method using the enzyme. (translated by NEDO)

  13. Suspension bridge with floor slab using precast PC slab; Yukaban ni purekyasuto PC burokku wo mochiita tsuribashi {center_dot} shinonome sakurabashi/tochigiken mibumachi



    As part of park improvement project of across of Kuro River flowing through Mibu Town of Tochigi Prefecture, a suspension bridge with floor plate using precast PC slab was erected. The size of floor block used is 5.5-7.5m in width, 2.5m in length, 14cm in thickness. 38 of these blocks were linked, resin was poured into joint, and stress was applied in bridge axis direction after hardening of resin. By prestressing, these floor slab had performance as reinforcing beam in normal loading condition, high rigidity of floor slab demonstrated excellent vibration stability. and enabled emergency vehicle traffic while this bridge is exclusively pedestrian use in normal time. Erection work was carried out in low water period of the river. Since the river can be reclaimed in low water period, most of erection work was carried out on land. Furthermore, utilizing advantages of precast slab, construction from erection of main tower to bridge completion was finished in only 3 months. (translated by NEDO)

  14. Study on detecting method of rail corrugation by using wavelet analysis; Wavelet kaiseki wo mochiita rail hajo mamo kenshutsu shuho ni kansuru kenkyu

    Suda, Y.; Okumura, M.; Komine, H.; Iwasa, T.; Terumichi, Y. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science; Qian, B. [The University of Tokyo, Tokyo (Japan)


    This paper reports the development of a method that detects the corrugation of a rail. A measurement test in which the track inspection car provided with an axle box accelerometer and irregular rail top face measurement equipment runs over the range of a specific section at the setting rate was conducted. A wavelet analysis is applied to the obtained acceleration data of vertical axle box vibration. The position of the generated corrugation was detected in a time base as the high position of a wavelet coefficient. Moreover, the dominant frequency range of corrugation was detected for each frequency by adding the wavelet coefficients in the whole position. This result was verified using the measurement data of an irregular rail top face. The wave height of corrugation can be estimated from the amplitude of the vertical vibration acceleration measured during low-speed traveling when the calculation result of a frequency response using the vertical vibration model in simplified wheel and rail systems is compared with the test result described above. 2 refs., 8 figs., 1 tab.

  15. Construction of educational application system for calligraphy master based on virtual reality; Virtual reality wo mochiita shodo shutoku no tame no kyoikuteki oyo system no kochiku

    Yoshida, T.; Muranaka, N.; Imanishi, S. [Kansai University, Osaka (Japan)


    Technique of virtual reality has been becoming popular in various fields including education because of its remarkable technique progress. There are the three useful elements of `presence`, `interaction` and `autonomy` in realizing the virtual reality. Here, we are focusing on the `presence` in constructing a simple supporting system for calligraphy education. We take advantage of the virtual image with reality to use as an educational interface because the virtual image and the real image are overlapped by showing the visual scene in the system. It is general that the unity of the virtual image and the real image has been processed as the stationary pictures by using `See-through HMD` and so on. In this paper, by using half mirror in stead of using the HMD with restraint, we are released from its restrainable sense. The virtual image and the real image are laid to overlap as the mobile pictures. The virtual hand replays the character inputted on the tablet by the excellent calligrapher. A calligraphic trainee is practicing overlapping the virtual hand which is reflected at the half mirror, while the trainee is doing the character on the tablet in the handwriting. The trainee is repeatedly practicing with feedback and is getting better in handwriting the character. It is shown in the good expermental results that the system has a proven effectiveness. 9 refs., 12 figs., 2 tabs.

  16. Digital data storage of core image using high resolution full color core scanner; Kokaizodo full color scanner wo mochiita core image no digital ka

    Takahashi, W.; Ujo, S.; Osato, K.; Takasugi, S. [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan)


    This paper reports on digitization of core images by using a new type core scanner system. This system consists of a core scanner unit (equipped with a CCD camera), a personal computer and ancillary devices. This is a modification of the old type system, with measurable core length made to 100 cm/3 scans, and resolution enhanced to 5100 pixels/m (1024 pixels/m in the old type). The camera was changed to that of a color specification, and the A/D conversion was improved to 24-bit full color. As a result of carrying out a detail reproduction test on digital images of this core scanner, it was found that objects can be identified at a level of about the size of pixels constituting the image in the case when the best contrast is obtained between the objects and the background, and that in an evaluation test on visibility of concaves and convexes on core surface, reproducibility is not very good in large concaves and convexes. 2 refs., 6 figs.

  17. Fabrication of band-pass filter using YBCO film at Ka-band frequency; YBCO hakumaku wo mochiita Ka-band taiiki tsuka fuiruta no sakusei

    Yoshitake, T.; Hattori, W.; Murakami, S.; Suzuki, S. [NEC Corp., Tokyo (Japan)


    In this report, Ka band microstrip band pass filter was produced experimentally using an YBCO system high temperature superconductivity thin film as examination initial stage high temperature superconductivity a thin film superscription communication element. With it, the following were examined: Evaluation method and frequency characteristics of the filter. Especially, the examination on structure of the package and system of measurement using refrigerating machine becomes important in order to evaluate the filter with the high frequency. (NEDO)

  18. Development of cryocooler-cooled solenoid magnet fabricated with Bi-2212 ROSAT wire; Bi-2212 ROSAT wire wo mochiita reitoki dendo reikyaku sorenoido magunetto no kaihatsu

    Azuma, K.; Morita, H.; Hara, N.; Okada, M. [Hitachi Ltd., Tokyo (Japan); Sato, J. [Hitachi Cable Ltd., Tokyo (Japan); Kitaguchi, H.; Kumakura, H.; Togano, K. [National Research Inst. for Metals, Tokyo (Japan)


    The asymmetry for external magnetic field is a small wire rod, while Bi-2212 ROSATwire keeps the transport current characteristics which tape wire rod is excellent. And, the wind ability becomes good by choosing the round cross section, and it is a wire rod, which is suitable for solenoidal coil. At present, refrigerating machine conduction cooling type solenoid magnet, which can generate central magnetic field 8T using this wire rod is developed. This time, the internal layer coil was manufactured, and the excitation test was carried out by the cooling system for the test. (NEDO)

  19. Development of superconducting magnets fabricated with PAIR processed Bi-2212/Ag multilayer tapes; PAIR purosesu Bi-2212/Ag taso senzai wo mochiita chodedo magunetto no kaihatsu

    Otani, N.; Koizumi, T.; Hasegawa, T. [Showa Electric Wire and Cable Co., Ltd., Kanagawa (Japan); Kitaguchi, H.; Kumakura, H.; Togano, K. [National Research Inst. for Metals, Tokyo (Japan); Miao, H. [Japan Science and Tech. Corp., Tsukuba (Japan)


    Bi2212 oxide superconducting wire rod has large critical current density at 20K or less. It is expected as practical conductors such as high magnetic field insert magnet and refrigerating machine cryogenic magnet. PAIR process, which we developed, introduced spare baking and intermediate preforming into the fabrication process of Bi2212/Ag wire rod. The superconductivity of the multilayer tape wire rod was more and more greatly improved, and it brought it close to the use conductor of the practical magnet. This time, in the coil using this wire rod, in order to examine electromagnetic force countermeasure in the high magnetic field application, the CuAg tape of which tensile strength was often high was used as reinforcing agent, and 2 kinds of double pancake coil were produced thermal conductivity. The coil was energized and was tested in 4.2K, in the external magnetic field. (NEDO)

  20. Development of cryocooler-cooled solenoid magnet fabricated with Bi-2212 ROSAT wire (2); Bi-2212 ROSAT wire wo mochiita reitoki dendo reikyaku sorenoido magunetto no kaihatsu (2)

    Morita, H.; Tanaka, K.; Hara, N. [Hitachi Ltd., Tokyo (JP)] [and others


    The asymmetry for external magnetic field is a small wire rod, while Bi-2212ROSATwire keeps the transport current characteristics which tape wire rod is excellent. And, the windability becomes good by choosing the round cross section, and it is goodwill wire rod in the solenoidal coil. At present, it develops refrigerating machine conduction cooling type solenoid magnet system using this wire rod. This time, it produced refrigerating machine conduction cooling system, which could install new internal layer coil using the wire rod improved and magnet of 3 layers. (NEDO)

  1. Development of resistive type superconducting fault current limiter using oxide superconductor; Sankabutsu chodendotai wo mochiita teikogata chodendo genryuki no kaihatsu -muyudo sorenoido koiru no shisaku shiken kekka

    Yoneda, E.; Shimada, M.; Nomura, S. [Toshiba Corp., Tokyo (Japan); Okuma, T.; Sato, Y.; Iwata, Y. [Tokyo Electric Power Co., Inc., Tokyo (Japan)


    We have advanced the development of resistive superconductivity current limiter using the normal transition of the superconductor until now, and it has produced and tested 6.6kV/1kA single-phase current limiter using the metal system superconductor experimentally. As a result of these evaluations, in turning to the practical application of that the oxide superconductor was used from the metal system superconductor from the viewpoint of wire rod performance, refrigerating machine, insulation performance, it reached the advantageous conclusion. Here, it reports the result that it produced the mischievous prank non-induction coil model experimentally in the mind and tested coil resistance type current-limiting element using the oxide superconductor. (NEDO)

  2. Development of new finite element by source method. 2nd Report. Plate bending element; Source wo mochiita atarashii yugen yoso no kaihatsu. 2. Itamage yoso

    Neki, I.; Tada, T. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)


    This paper reports a method to develop a new finite element by source (FES) for a two-dimensional plane problem and a three-dimensional solid problem as a method to analyze ship body structures. The paper describes development of a plate bending element by using a similar method, and the fundamental principle thereof. The present method can prepare a finite element of an arbitrary shape by simply providing a contact point only on a boundary. It can also derive good calculation accuracy with less number of contact points and elements. These facts are shown by examples of analyses on a square plate, a triangle plate and a semi-circular plate. Particularly, since a plate bending problem has a large order of differential calculus in a governing equation, this method being a semi-analytical method derives a result with very good accuracy even with less number of contact points. A hypothetical boundary method or a hypothetical electric charge method presents not a very high accuracy even if a large number of contact points are provided. This is because the method hypothesizes only a bending moment vertical to the boundary, but does not consider a source of the moment relative to the boundary. In contrast, the present method hypothesizes both of bending and twisting as the sources, hence its accuracy is better than with the above two methods. 5 refs., 11 figs., 7 tabs.

  3. Co-generation system with a linear concentrator and thermoelectric elements; Senkei shukokei to netsuden henkan soshi wo mochiita netsuden heikyu system

    Kachi, E.; Suzuki, A.; Fujibayashi, K. [Tokyo University of Agriculture and Technology, Tokyo (Japan)


    The co-generation system using a solar cell has the disadvantage that the performance of a cell element deteriorates when the temperature rises. Therefore, the co-generation system in which a BiTe thermoelectric element and linear Fresnel lens are used was constructed. Moreover, the basic characteristics were confirmed and the characteristics of a system model were analyzed. A thermoelectric element area must be reduced to improve the generating efficiency. The generating efficiency depends on the temperature difference between thermoelectric elements rather than the thermoelectric element area. As the thermoelectric area gets lower, the generating efficiency will get higher. This inclination is advantageous on the economic side. The generating efficiency becomes low during operation at high temperature. As a result, the temperature supplied to the thermal load is set to the lower position (100 to 200{degree}C) so as to advance the validity of the system. Even if the co-generation temperature is low, a heat supply capability of 150{degree}C is sufficient for an industrial heat supply system because it holds a large majority of the consumption demand for the whole industry. 3 refs., 8 figs., 3 tabs.

  4. Indirect solar-pumped laser diode using a solar cell; Taiyo denchi wo mochiita taiyoko kansetsu reikigata handotai laser no kaihatsu

    Kanamori, Y.; Yugami, H.; Naito, H.; Arashi, H. [Tohoku University, Sendai (Japan). Faculty of Engineering


    This paper describes the operating characteristics of a stabilizing circuit using commercial electricity, those of a stabilizing circuit using solar cells, relation between the quantity of solar radiation and the maximum output of a semiconductor laser diode (LD), and simulation results of annual LD output in Sendai City. The stabilizing circuit for the solar-cell driven LD was structured such that the output of the solar cell panels was guided to a DC/DC converter, that the voltage was set at a prescribed value and that the current was stabilized with the use of power MOSFET. The solar cells used in the experiment were monocrystal silicone solar cells with the maximum output of 53W each. In the experiment, the LD was protected by stabilizing the current at a set value when an excess current was supplied to the stabilizing circuit. As a result of the simulation of the annual LD output from the meteorological data of Sendai City, it was predicted that a solar cell of approximately 1kW was able to provide an annual output of 102MJ and that the efficiency was highest with four sheets of the solar cell. Consequently, consistency proved to be essential between the LD and the solar cell output. 3 refs., 7 figs.

  5. Simulation study using 3-D wavefield modeling for oil and gas exploration; Sanjigen hadoba modeling wo mochiita sekiyu tanko no simulation study

    Sato, T.; Matsuoka, T. [Japan Petroleum Exploration Corp., Tokyo (Japan); Saeki, T. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center


    As the surroundings of objects of oil exploration grow more complicated, seismic survey methods have turned 3-dimensional and, in this report, several models are examined using the 3-dimensional simulation technology. The result obtained by the conventional wave tracking method is different from actual wavefields, and is unrealistic. The difference method among the fullwave modelling methods demands an exorbitantly long computation time and high cost. A pseudospectral method has been developed which is superior to the difference method, and has been put to practical use thanks to the advent of parallel computers. It is found that a 3-dimensional survey is mandatory in describing faults. After examining the SEG/EAGE Salt model, it is learned that the salt is well-developed and that 3-dimensional depth migration is required for sub-salt exploration. It is also found through simulation of the EAGE/S Overthrust model, which is an elastic model, that no quality records are available on thrust zones in complicated terrains. The records are poor in quality since the actually measured wavefield is regarded as an acoustic wavefield when it is an elastic wavefield. 1 refs., 18 figs., 2 tabs.

  6. Density Measurements of Na2WO4-WO3-ZnO Melts


    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.

  7. Electrochemical Preparation of WO_3 Nanowire Arrays


    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...

  8. Synthesis and characterization of WO3 nanomaterials.

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


    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.

  9. New ion generation method with SF{sub 6} plasma. Direct ionization of refractory materials; SF{sub 6} purazuma wo mochiita atarashii ion seiseiho. koyuten busshitsu wo chokusetsu ion ka

    Okoshi, K.; Saito, Y.; Tajima, S. [Japan Atomic Energy Research Institute, Tokyo (Japan)


    For many refractory materials, vapor pressures rise due to fluoridation. For example, a vapor pressure of B is almost zero at room temperature, whereas a vapor pressure of BF{sub 3} is 10{sup 5}Pa or greater. A SF{sub 6} plasma method is capable of directly generating a solid fluoride in an ion source and obtaining its plasma. In order to ionize refractory materials such as niobium, boron, silicon and the like, the present authors have developed a new ion generation method using a stable solid sample and SF{sub 6} gas. Further, the present method was employed to successfully and greatly extending the filament life of the ion source. The plasma method can be used widely not only for a Freeman ion source but also for an ion source using plasma such as electron cyclotron resonance (ECR) ion source. Since the refractory material ions can be stably supplied at a great intensity for a long time, they are expected to be used in corrosion-resistant materials or materials having new functions such as optical switching materials. (NEDO)

  10. Wide stop-band filters consisted of optical directional coupler type multi resonators; Hikari hokosei ketsugoki wo mochiita fukugo kyoshinki ni yoru kososhiiki wo yusuru koha fuiruta no kento

    Furuta, Hirosuke; Nishikawa, Kenji; Miyamoto, Tokuo


    It is important that pass-band and stop-band of the optical filter used for optical wavelength division multiplexing systems can be set up according to systems requirements. In this paper, we presented expanding of stop-band using multi-resonator consisted of optical directional coupler. In this resonator, addition to interferences by resonation, the path length difference between two different path from input-port to output-port cause intensity changes. To use these interferences, we considerated expanding of stop-band and suppressing of resonate peak in stop-band. 30GHz passband and 60GHz cut-off frequency at 20dB point are calculated. If expanding the stop-band up to 10THz, the loss in the stop-band coms down to 24dB. (author)

  11. Reaction mechanism of active carbon manufactured by chemicals activation method using potassium carbonate from a raw material of tofu refuse; Okara wo genryo toshi tansankariumu wo mochiita yakuhinfukatsuho niyoru kasseitan seizo niokeru hannokiko

    Hayashi, Jun' ichi; Muroyama, Katsuhiko; Furukawa, Akira; Takemoto, Shin [Kasai University, Osaka (Japan)


    The authors attempted to manufacture active carbon using potassium carbonate as an activator from a raw material of tofu refuse. As the results, the active carbon having a large specific surface area of 2,656 m{sup 2}/g at a carbide and an activation temperature of 800 degrees C could be manufactured. It was clarified as follows after investigating the activation mechanism: potassium carbonate changed to potassium peroxide and potassium sulfate in the reaction of tofu refuse and potassium carbonate in the impregnation and dry process. The tofu refuse was changed into a low molecular weight component and a water soluble organic constituent increased. As the results, the weight loss behavior of he tofu refuse changed up to the carbonization - activation temperature of 500 degrees C and then the carbide having a large specific surface area which had a different pore structure of carbide made independently from the tofu refuse was generated. With further increasing the temperature up to 700 degrees C, it was considered that carbon consumed due to a reduction of potassium carbonate by carbon of carbide, the specific surface area was greatly increased, and active carbon having a high specific surface area was manufactured. (translated by NEDO)

  12. The Preparation of CoWO4/WO3 Nanocomposite Powder

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


    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.

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

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


    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.

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

    Ahmadi, Majid; Sahoo, Satyaprakash; Younesi, Reza


    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...

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

    Muerk, V; Mihoková, E; Nitsch, K


    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)

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

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


    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.

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

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


    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.

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

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


    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.

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

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


    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.

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

    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)


    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.

  1. Kinetics and mechanism of dye adsorption on WO3 nanoparticles

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


    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.

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

    Markasagayam Visagamani Arularasu


    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.

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

    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: [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Hu, Chenguo, E-mail: [Department of Applied Physics, Chongqing University, Chongqing 400044 (China)


    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.

  4. WO3 Nanoplates Film: Formation and Photocatalytic Oxidation Studies

    Chin Wei Lai


    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.

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

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


    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.

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


    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.

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

    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)


    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)

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

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


    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.

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

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


    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.

  10. Structure and photocatalytic performance of layered HNbWO6 nanosheet aggregation

    Hu, Li-Fang


    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.

  11. Preparation and physical properties of CuxWO3

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


    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.

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

    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)


    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).

  13. Hydrothermal synthesis and chromic properties of hexagonal WO3 nanowires

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


    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.

  14. Radioactive contamination of ZnWO4 crystal scintillators

    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


    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...

  15. On the dynamic behavior of a wind turbine-generator system with a Darrieus-Savonius hybrid wind turbine; Hybrid furyoku turbine wo mochiita furyoku hatsuden system no kyodo ni tsuite

    Wakui, T.; Tanzawa, Y.; Hashizume, T.; Ota, E. [Waseda University, Tokyo (Japan). School of Science and Engineering; Terashima, Y.; Machiyama, T. [Nippon Institute of Technology, Saitama (Japan)


    In order to clarify the dynamic characteristics of a self-controlled Darrieus-Savonius hybrid wind turbine system, a system consisting of a hybrid wind turbine and an AC generator was tested under various wind conditions in the wind tunnel. We took up four types of wind blowing change for the test; ramp, sinusoidal and square wind velocity changes and a similar wind velocity change to the field wind. A series of tests substantiated the effectiveness of our operating scheme wherein the tip speed ratio is maintained at a constant value. On the other hand, theoretical studies have been carried out on the characteristics of the system. A simulation model is presented in order to describe the system characteristics not only for the steady-state behavior but also for the dynamic behavior. In spite of its simplicity, the model can predict both characteristics of the system well. The appropriateness of the simulation model is confirmed by comparing with the experimental results. -In addition, the field test data are discussed. As a result, it is confirmed that the system is operated and controlled satisfactorily in the field. 14 refs., 19 figs., 3 tabs.

  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

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


    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. Estimation of real ship propelling performance by the surface velocity lattice method using model ship flow field data; Mokeisen ryujo data wo mochiita hyomen uzu koshiho ni yoru jissen suishin seino no suitei

    Kai, H.; Ikehata, M.; Sakai, S. [Yokohama National University, Yokohama (Japan). Faculty of Engineering


    This is basically a technique wherein the wing element method is replaced by a surface vortex lattice method. A horseshoe vortex of unknown intensity and source surface of known intensity are distributed on the wing surface and, under conditions that the fluid will not cross the boundary, the intensity of horseshoe vortex circulation is calculated for the solution of the fluid field. For the simulation of a real ship in navigation, the required propeller revolution thrust is determined using the real ship resistance value and real ship thrust reduction factor estimated from a model ship resistance test by extrapolation. The calculation of propeller performance is conducted in the quasi-steady condition using the force of fluid working on one wing for each wing angle (with the wing rotated at the increment of 6 degrees), and the thrust and torque are determined using the averages of values obtained in one cycle. It is found that the torque value is overestimated in a considerable degree in the wing element theory. In the surface vortex lattice method, both thrust and torque values agree with experimental values mostly, and this method is found to be accurate enough as a navigation element calculation tool when many panels are considered. 4 refs., 5 figs., 1 tab.

  18. Development of movie caption translation lecture site using MobileMotion{sub TM}; MobileMotion{sub TM} wo mochiita jimaku hon'yaku koza site no kaihatsu



    The site of Internet that performs the correspondence education for bringing up a movie caption translator was developed. Correspondence education that fully deepens understanding was obtained by distributing a motion picture using MPEG-4 distribution software (MobileMotion{sub TM}) and performing the learning based on bi-directional communication. HTML distribution and E-mail transmission and reception are done from Gaga Communications, and a MobileMotion{sub TM} file is distributed from the OnDemand Server of Toshiba. This reduces the communication traffic of heavy motion picture data. (translated by NEDO)

  19. Positron lifetime measurements and positron-annihilation induced auger electron spectroscpy using slow positron beams; Teisoku yodenshi bimu wo mochiita yodenshi jumyo sokutei oyobi yodenshi shometsu reiki oje denshi bunko

    Suzuki, R. [Electrotechnical Lab., Tsukuba (Japan)


    Slow positron beam with less than several eV can be controlled freely such as accelerating, throttling the beam size, shortening the pulse or making pulse with short time width and so forth. These low positron beams are applied to various measurements like Doppler broadening measurement of annihilation {gamma} rays or lifetime measurement of positron, and secondary particle measurements using positron microscope, positron electron ray diffraction, flight time method and so forth. In particular, these recent years, high intensity slow positron beams were possible using accelerators like electron linac and its application is increasing. In this report, pulse shortening method for high intensity slow positron beam, and incidence energy variable positron lifetime measurement method using this slow pulsed beam and flight time type positron-annihilation-induced auger electron spectroscopy are outlined. In future, these measurements can be possible to carry out with high resolution and also with high counting rate if higher intensity monochromatic excellent positron beam than present one is produced. 31 refs., 5 figs.

  20. 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

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


    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.

  1. Magnetic properties of Nd-Fe-B magnets sintered using granulated powders by spray drying method. 3; Spray zoryufun wo mochiita Nd-Fe-B shoketsu jishaku no jiki tokusei. 3

    Kishimoto, Y. [Sumitomo Metal Industries Ltd., Osaka (Japan); Yamashita, O. [Sumitomo Special Metals Co. Ltd., Osaka (Japan)


    Using two kinds of polymers with different tensile strengths and plasticizer as binders for the spray drying method of Nd2Fe14B rare earth system alloy powder, the relation between binder composition and powder characteristics or sintered magnet characteristics was studied. The binder polymers with high tensile strength improved the binding strength between alloy powders, and formed the secondary grain powder with a flowability superior in granulation. An increase in residual carbon was controlled to 200-300ppm by decarbonization at 673K for 0.5h. Reduction of an oxygen content in granulated powders was important for improving magnet characteristics. Magnet characteristics of sintered bodies were largely dependent on the amount of added plasticizer. The higher flexibility of binders due to addition of more amount of plasticizer reduced the binding strength between alloy powders and slightly reduced the flowability, however, improved magnet characteristics. The binder composed of PVA of 0.2wt% and plasticizer (glycerine) of 0.09wt% was most suitable. 4 refs., 7 figs., 1 tab.

  2. Evaluation of the autonomic neuropathy function immediately after a change to upright posture using the impulse response function; Impulse oto kansu wo mochiita shisei henkan katoki ni okeru jiritsu shinkei kino hyoka

    Yokoyama, K. [Nagoya City University, Nagoya (Japan); Moyoshi, M.; Takata, K. [Daido Institute of Technology, Nagoya (Japan); Watanabe, Y. [Toyota College of Technology, Aichi (Japan)


    Autonomic neuropathy function immediately after a change to upright posture has been evaluated by applying transient response function of the system to the blood regulation system. The impulse response function was determined from the change in heart rate before postural change to the upright posture, and was compared with the transient change immediately after a change to the upright posture. The time series of R-R interval of electrocardiogram was used as the time series of the change in heart rate. To determine the impulse response function, an autoregressive model was applied to the R-R interval time series. The impulse response function at the steady state is a transient reaction at the impulse stimulation added to the blood regulation system. The R-R interval decreases rapidly by the autonomic neuropathy reaction in which the blood is rapidly transferred into the legs immediately after a change to upright posture. There is a close correlation between the initial temporary decrease in R-R interval and the impulse response function derived from the change in heart rate immediately after a change to the upright posture. Accordingly, the blood regulation and autonomic neuropathy functions can be evaluated by the impulse response function without actual standing test and load of tested persons. 9 refs., 3 figs., 1 tab.

  3. Resolution of digital servo control system using single-bit digital signal processing; 1 bit digital shingo shori wo mochiita seigyo no bunkaino to johoryo ni tsuite no simulation

    Tojo, K.; Kurosawa, M.; Oka, K.; Higuchi, T. [The University of Tokyo, Tokyo (Japan)


    The application of single-bit digital signal processing to mechanical control system has already been proposed by the authors. Multi-bit A/D converter has been improved to the high level. But it is difficult to make more high resolution A/D by latest semiconductor technologies. There is single-bit digital signal which is generated by a delta-sigma modulator. Single-bit digital signal has small quantized error around low frequency. Then with this single-bit digital signal processing, high resolution on controlling such a narrow band width mechanical system will be realized. In this paper, resolution of analog, multi-bit and single-bit control systems are estimated with simulation. According to simulations` results, single-bit control system has higher resolution than multi-bit system in the condition of equal bit rate. 5 refs., 17 figs., 1 tab.

  4. Modified spatial autocorrelation method using autoregressive model for estimating underground velocity structure from microtremor array observation; Bido array tansa ni okeru kukan jiko sokanho no jiko kaiki model wo mochiita kairyo

    Yamamoto, H.; Saito, T. [Iwate University, Iwate (Japan). Faculty of Engineering; Obuchi, T. [Kawasaki Geological Engineering Co. Ltd., Tokyo (Japan)


    Spatial autocorrelation method (SAC) is an effective analysis for estimating underground S-wave velocity structure from microtremor phase velocity dispersion relation because it has larger detectable range of microtremor wavelength than frequency-wavenumber analysis. However, phase velocities estimated by conventional SAC methods such as band-pass filtered method or Fast Fourier Transform method were not precise if suitable band width was not selected for analysis. We proposed a new technique for SAC using autoregressive model which estimated spectra with high resolution because the best fitting model can be selected using AIC. We apply the new method to calculate phase velocities of microtremors which were observed at a ground of Morioka Technical High School with arrays. As a result, phase velocities calculated by the new method were continuous with frequency although those calculated by the conventional methods were scattered. This indicates that SAC functions calculated by the new method are estimated better than those by conventional SAC methods. 13 refs., 7 figs.

  5. Advanced mineral and lithological mapping using high spectral resolution TIR data from the active CO2 remote sensing system; CO2 laser wo mochiita kosupekutoru bunkaino netsusekigai remote sensing data no ganseki kobutsu shikibetsu eno oyo

    Okada, K. [Sumitomo Metal Mining Co. Ltd., Osaka (Japan); Hato, M. [Earth Remote Sensing Data Analysis Center, Tokyo (Japan); Cudahy, T.; Tapley, I.


    A study was conducted on rock/mineral mapping technology for the metal ore deposit survey using MIRACO2LAS, an active type thermal infrared ray remote sensing system which was developed by CSIRO of Australia and is now the highest in spectral resolution in the world, and TIMS of NASA which is a passive type system. The area for the survey is the area of Olary/Broken Hill and Mt. Fitton of Australia. A good correlation is seen between the ground reflectance measured by MIRACO2LAS and the value measured by the chamber CO2 laser of rocks sampled at the above-mentioned area. In case that the width of spectral characteristics is below 300nm, the inspection ability by MIRACO2LAS`s high spectral resolution is more determined in mineral mapping as compared with TIMS which is large in band width. Minerals mapped using MIRACO2LAS are quartz, talc, amphibole, hornblende, garnet, supessartine, dolomite, magnesite, etc. 4 refs., 3 figs.

  6. Study of signal transduction mechanism of angiotensin 2 receptor by means of site-directed mutagenesis; Bui totsuzen hen'iho wo mochiita anjiotenshin 2 reseputa no joho dentatsu kiko no kaimei

    Yamano, Yoshiaki [Tottori University, Tottori (Japan). Faculty of Agriculture


    The renin-angiotensin system (RAS) plays an important role in the regulation of blood pressure. In order to clarify the signaling mechanism mediated by angiotensin 2 receptor, Gq-protein binding amino acid residues of this receptor were clarified by site-directed mutagenesis study. Amino acid residues in the carboxyl tail region were changed by alanines, individually. These mutated receptors were expressed stably in CHO cells, and GTP effect and second messenger molecules were determined, and three residues (Y 312, F313 and L 314) in this region were determined to be concerned for the binding of Gq protein. The other signaling systems, Gi, MAP kinase, JAK-STAT mediated, were reported to be concerned for this receptor. Novel drags for high blood pressure therapy would be explored by clarifying these signaling mechanisms. (author)

  7. Magnetic field distributions on Ag-Bi2223 tape by the magnetic optical and scanning hall sensor measurements; Jiki kogakuho oyobi sosagata horu soshiho wo mochiita Ag-Bi2223 tepu hyomen deno jiba bunpu

    Otake, A.; Ota, A. [Toyohashi Univ. of Tech., Aichi (Japan); Kawano, K.; Abell, S.


    We have measured the magnetic field distribution of silver sheath Bi2223 wire rod in the surface until now using the scanning Hall element method. In magnetic field distribution measuring method, there is magneto-optic method using the Faraday effect of a magnetism network film except for the Hall element method. We measured the magnetic field distribution of silver sheath Bi2223 wire rod using two techniques of the Hall element and magneto-optics method in order to understand magnetic field distribution further, and both results were compared and were examined. (NEDO)

  8. Measurement of trapped magnetic fields on Ag-sheathed Bi-2223 monofilamentary tapes using scanning Hall sensor; Sosagata hall soshi wo mochiita gin sheath Bi2223 chodendo tanshin tape hyomen deno jisoku mitsudo sokutei

    Kawano, K.; Ota, A. [Toyohashi University of Technology, Aichi (Japan). Faculty of Engineering


    Two-dimensional self-field distribution was measured on the surface of Ag-sheathed Bi-2223 superconducting monofilamentary tapes using a scanning Hall sensor, to obtain the current distributions within the specimens. Based on the electromagnetic consideration, path of current flow within superconducting cores under the critical condition was modeled. Magnetic field profiles were calculated in the case of strong links of grain boundaries where high critical current density (Jc) can be expected due to the intergranular current transport, and in the case of weak links of grain boundaries where high Jc can not be expected due to local intragranular current transport. When assuming the intergranular current, calculated Jc was lower than the measured one. Distribution of Jc in the superconducting cores was suggested. When the weak link was artificially introduced in the specimens, residual magnetic field changed remarkably at the ends of superconducting cores, but it did not change at the center of cores. Such behaviors of magnetic field could be explained from the results calculated by assuming the intragranular current. This was found to be caused by the presence of intergranular weak links. 15 refs., 11 figs., 2 tabs.

  9. Ethanol production by high cell-density culture with periodic reversion of circulating flow in cross-flow filtration. Ryudo hoko henkan cross flow rokaho wo mochiita komitsudo baiyoho ni okeru ethanol seisan

    Asakura, T.; Toda, K. (The University of Tokyo, Tokyo (Japan). Institute of Applied Microbiology)


    For the purpose of effective production of ethanol, high cell-density culture was examined using a bioreactor with a flat-membrane filtlation module for three kinds of ethanol production microorganism, and the productivity of ethanol fermentation was investigated. The flow direction of the culture broth circulating along a flat membrane in the filtration module was changed periodically, at intervals of 4 minutes and 1 minute, as a result of which, the filtration flux was stabilized to some degree and increased five-fold over that of the control experiment. When the cell concentration in the reactor was maintained at a constant by draining broth at a proper rate, the filtration flux was stabilized further and increased twenty-fold over that of the control experiment. The productivity and exit concentration of ethanol in this cell recycle culture when the cell concentration was 200 gl{sup {minus}1} of Bakers yeast, were 83.7 gl{sup {minus}1}h{sup {minus}1} and 30.2 gl{sup {minus}1}, respectively. For the other two kinds of yeast, high ethanol concentration and productivity were confirmed, concluding that this production method was effective. 25 refs., 9 figs., 1 tab.

  10. Coal demineralization with Ca(OH)2. Hydrothermal reaction between Ca(OH)2 and quartz; Ca(OH)2 wo mochiita sekitan no kagakuteki dakkai. Ca(OH)2 to sekitan no suinetsu hanno

    Wang, J.; Tomita, A. [Tohoku University, Sendai (Japan). Institute for Chemical Reaction Science


    Coal demineralization mechanism and its optimum condition were studied by hydrothermal reaction between Ca(OH)2 and quartz as a coal demineralization model. In experiment, the mixture of powder quartz and Ca(OH)2 water slurry was subjected to reaction in an autoclave under spontaneous pressure at 175-340{degree}C. After dried in N2 gas atmosphere at 105{degree}C, the reaction product was analyzed by X-ray diffraction, thermo-balance and differential thermal analysis. In measurement of quartz conversion, the specimen was analyzed by X-ray diffraction after removal of bound water by heat treatment at 850{degree}C. The mixture of clean coal deashed by NaOH and a fixed amount of quartz was also used as specimen for experiment. As the experimental result, dicalcium silicate hydrate was mainly produced at 175{degree}C, and the product changed into xonotlite through tobermorite by longer treatment at higher temperature. For complete reaction of quartz, heat treatments for 7 and 5 hours at 300 and 400{degree}C were necessary, respectively. 2 refs., 2 figs., 2 tabs.

  11. 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

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


    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.

  12. Toxicity assessment of organochlorine compounds detected in water environment using cultured human cell lines; Hito yurai saibo baiyokei wo mochiita suikankyo shiryochu no yuki enso kagobutsu no dokusei hyoka

    Kunimoto, M.; Yonemoto, J.; Soma, Y.; Nakasugi, O. [National Institute for Environmental Studies, Tsukuba (Japan)


    As part of validation processes of in vitro toxicity assays for the risk assessment of environmental hazards, we applied an in vitro toxicity test using two human cell lines, neuroblastoma NB-1 cells and glioblastoma U-87 MG cells, to the assessment of organochlorine compounds detected in the water environment. The in vitro toxicity assay using NB-1 cells was calibrated by testing reference chemicals proposed by MEIC (Multicenter Evaluation of In Vitro Cytotoxicity), an international program for the validation of in vitro cytotoxicity assays. Beforehand, an assay using cells in frozen stock without subcultivation was examined by comparing IC50 values with the ordinary assay using subcultured cells. IC50 values for MEIC reference chemicals from the former assay showed good correlation with those from the latter assay, suggesting that the assay using cells in frozen stock can be used at least for the assessment of basal cytotoxicity. IC50 values for ten organochlorine compounds frequently detected in the sediment samples from contaminated rivers, p-chloroaniline, 3,4-dichloroaniline, p-dichlorobenzene, o-dichlorobenzene, Tris (2-chloroethyl)-phosphate, 2,5-dichlorophenol, 2,5-dichloroanisol, Triclosan and Triclocarban, were obtained with the in vitro assays and compared with their LD50 values in rats. No significant correlation, however, was seen between the IC50 and LD50 values, indicating that further improvement of in vitro toxicity assays is necessary for the application to the risk assessment of environmental hazards. 7 refs., 4 figs., 1 tab.

  13. Experiment for detecting metallic-bars in concrete using new 1.5 GHz antenna; Shingata no 1.5 GHz antena wo mochiita konkureto nai no tekkin tansa jikken

    Nakabayashi, Yuko; Toshioka, Tetsuma; Goebuchi, Toru [Oyo Corp., Tokyo (Japan)


    In recent years, maintenance was increasingly needed with the aging of the concrete structures. It has been paid attention to the underground radar detection as a non-destructive detection methods in order to confirm the bar arrangement situation inside concrete. However, in the metallic bar detection using the common underground radar, it was difficult to identify the metallic bar position and concrete cover thickness when an interval of metallic bars was dense or arrangement of metallic bars was overlapped, in a case of which the metallic bars were buried in extremely shallow areas such as metallic bar concrete wall. In the application experiments of this time, it was confirmed by using the new and high frequency antenna with central frequency of 1.5 GHz that the metallic bar position and concrete cover thickness could be identified which position and concrete cover thickness were difficultly identified by the common methods by the underground radar detection in arrangement of metallic bars. (translated by NEDO)

  14. Practical use of technology for exploring obstacles and soil collapse state around shield machine using underground radar; Chichu reda wo mochiita shirudo ki shuhen no shogaibutsu to dosha hokai jotai tansa gijutsu no jitsuyoka

    Tanimoto, K. [Mitsubishi Heavy Industries Ltd., Tokyo (Japan)


    A report is made on the outline and the used result of a newly developed `underground radar.` The objects for underground exploration in shield tunneling methods are divided broadly into obstacles, state of the peripheral ground, and geological change in the working place. Electromagnetic method is employed for the exploration method of this system which can explore the ground conditions very accurately and in real time although the explorable distance is a little limited. As to antennas, there are two types, i.e. the separate transmitter and receiver antenna and the integrated transceiver antenna. The antennas are mounted at the side of cutter face, at the shield machine fixed side, and at the front of the cutter face. The system configuration varies according to the type of antenna and the displaying location of the explored result. The system introduced in this report consists of a radar antenna, antenna control device, slip ring, measurement control computer, and monitoring computer. A report is made on the condition of an existing buried pipe found accidentally during drilling with a shield machine. 12 figs., 1 tab.

  15. Synthesis of (E)-9-Oxo-2-decenoic acid (the queen substance of honeybee) from methyl 3-formylpropionate; 3-horumiruporopion san mechiru wo mochiita (E)-9-okiso-2-desen san (Mitsubachi joo busshitsu) no gosei

    Tsukasa, H. [Toyotama Koryo Co. Ltd., Tokyo (Japan)


    The queen substance, (E)-9-oxo-2-decenoic acid (1) is a pheromone secreted by queen honeybee (Apis mellifera) and inhibits reproductive ability of worker bees. Several synthesese have been reported. It was synthesized starting from methyl-3-formylpropionate this time. Methyl 7,7-ethylenedioxy-4-oxooctanoate was prepared by radical addition reaction from (2) and 2-methyl-2-vinyl-1,3-dioxolane and reduced to an ethyelenedioxy carboxylic acid with hydrazine and KOH. This compound was converted to an alcohol by reduction with sodium bis(2-methoxyethoxy)aluminum hydride, followed by oxidation with pyridinium chlorochromate to an acetal aldehyde, which was condensed with malonic acid and (1) was obtained after the hydrolysis with hydrochloric acid. 7 refs., 1 tab.

  16. Relation between front suspension layout and handling performance. Analysis depending on the Taguchi method and ADAMS; Front suspension layout to soda tokusei no kankei ni tsuite. Kiko kaiseki gengo wo mochiita hinshitsu kogaku ni yoru kaiseki

    Okada, K. [Daihatsu Motor Co. Ltd., Osaka (Japan)


    A variation of suspension layout gives an influence to the vehicle dynamics. Examined the suspension layout variation to make the handling performance change small. Analyzed the effect of suspension layout variation about steering response delay and gain besides the tire wear effect and movable load. 3 refs., 12 figs., 4 tabs.

  17. Heat release characteristics of middle temperature latent heat storage vessel by means of direct contact heat exchange method; Chokusetsu sesshoku netsu kokanho wo mochiita chuondo sennetsu chikunetsuso no honetsu tokusei

    Inaba, H.; Horibe, A.; Ozaki, K. [Okayama University, Okayama (Japan). Faculty of Engineering; Emoto, K. [Okayama University, Okayama (Japan); Kakiuchi, H. [Mitsubishi Chemical Corp., Tokyo (Japan)


    Experiment has been performed of heat transfer characteristics of the middle temperature latent heat storage system of the direct-contact heat transfer by using m-E (meso-Erythritol, melting point of 119 degree C, latent heat of 375 kJ/kg) droplets as a latent heat storage material and silicone oil as a heat transfer medium. In the present study the liquid m-E was injected into the heat transfer medium through a circular nozzle. The m-E droplets changed from liquid to solid phase during falling in the heat transfer medium at low temperature. From the measuring results of m-E droplet diameter, falling velocity, and solidification rate, the nondimensional empirical equations of the arithmetic mean diameter of the droplets and falling velocity, the solidification rate and the overall heat transfer coefficient were derived as a function of the characteristic arithmetic mean diameter, the terminal velocity, temperature and physical properties. (author)

  18. Robust stabilization control of power system based on the direct control of generator power by series variable impedance unit; Chokuretsu kahen inpidansu wo mochiita hatsudenki denryoku no chokusetsu seigyo ni yoru robasuto keito anteika seigyo

    Hojo, M.; Mitani, Y.; Tuji, K. [Osaka University, Osaka (Japan)


    Advanced control system design method (whose application is believed to be difficult in practical use) with the advancement of technologies of power system stabilization controllers has received much attention. In particular, demand of stabilizing control system with high robustness is pointed out. Construction of linearization control system is proposed based on direct operating volume of electric output power`s generator using the series variable impedance unit in this paper. The results are summarized as follows. Based on direct control aim of a generator power out of system of controllers with reference to the swing characteristics of power generator under specification, a linearized control is manufactured. Proposed control based on simple construction using variable impedance unit which is connected continuously with transmission line is realized. Linear system which keeps eigen values pointed out by designers who predicts based on the use of proposed controller is obtained. 6 refs., 11 figs., 2 tabs.

  19. System identification of a high-rise building applying multi-input-multi-output ARX model of modal analysis; Mode kaisekigata tanyuryoku tashutsuryoku ARX model wo mochiita koso kenbutsu no system dotei

    Saito, T. [Shimizu Construction Co. Ltd., Tokyo (Japan)


    Recently, with the increase of high-rise building construction, better precision is in demand in case of building model used for analyzing seismic, wind responses in the design. Particularly, the decay constant has been given uniformly for each type of structures, however, application of estimated value from practically measured results of real high-rise building in the design is preferred. In this report, purpose is to estimate the model parameters of multi-input-multi-output system by making optimum use of benefits of system identification using ARX model. Further, multi-input-multi-output ARX model based on the idea of mode analysis was established by revealing in common the self-regression coefficient for each output and algorithm for estimating its model constant was developed. Further, system identification was carried out by applying this proposed model in real seismic response record of high-rise building, effectiveness of the model was verified and seismic vibration characteristics of the building was evaluated. 27 refs.,10 figs., 2 tabs.

  20. Fiscal 2000 achievement report. Development of foaming eco-material utilizing magazine wastepaper (3rd fiscal year); 2000 nendo zasshi koshi wo mochiita happo seikei eco material no kaihatsu seika hokokusho (dai 3 nendo)



    Efforts are exerted to develop cushioning material (packing material) manufacturing technologies making use of low-grade wastepaper, to commercialize a low environmental impact type cushioning material, and to promote wastepaper recycling. Activities are conducted in the three domains of (1) the development of a technology for manufacturing a foaming eco-material out of magazine wastepaper, (2) the development of manufacturing equipment, and (3) a market survey. Crushed wastepaper in a gelatinous water solution is vigorously stirred for the gelatine to go into a crosslinking reaction, and is dried for the manufacture of a cushioning material (foaming material). In domain (1), technologies for controlling crosslinking reaction and physical properties are developed, and raw materials and target material manufacturing conditions are selected so that the product price will be not higher than the price of expanded polystyrene. In fiscal 2000, studies were made on wastepaper fiber composition, characteristics of a binder to use, and plant operating conditions, and a technology was developed that stabilizes the specific weight of the foam product at 0.10 or less. Foam products were manufactured by way of trial for use with domestic appliances and optical equipment. (NEDO)

  1. Reduction of industrial waste by the employment of simultaneous desulfurization/graphite spheroidization method using magnesium; Maguneshiumu wo mochiita datsuryu/kokuen kyujoka doji shoriho no saiyo ni yoru sangyo haikibutsu no teigen

    Toriyama, T.; Yamamuro, S.; Yoshida, A.; Ono, S. [Kurimoto Ltd., Osaka (Japan)


    The Sakai Factory of KURIMOTO LTD. employed a continuous porous plug desulfurization method in 1992. In this desulfurization method, the molten iron from a cupola is desulfurized with a desulfurizing agent in which calcium carbide and lime are mixed. This paper reports the details of the development of a simultaneous desulfurization/graphite spheroidization method using Mg, which aims at disusing the operation in a high-temperature environment and reducing the quantity of slag which is an industrial waste. The main results obtained are as follows. The quantity of desulfurized slag in a porous plug ladle could be reduced to zero. A total quantity of slag produced was reduced by about 70%, which was better than the target reduction. Owing to the employment of this simultaneous desulfurization/graphite spheroidization method using Mg, the operations of mixing the desulfurizing agent and removing desulfurized slag in a high-temperature environment were omitted. The S-value after the simultaneous desulfurization/graphite spheroidization became lower than 0.010%. It could be ascertained that the graphite spheroidization rate and mechanical properties of the product did not differ from those of the product obtained by a conventional desulfurization and fully satisfied the standard values of the product. 8 figs., 4 tabs.

  2. Evaluation of geological conditions by ''drilling logging system''. Yuatsu drill ni yoru sakuko data wo mochiita ganban hyoka oyobi kiriha zenpo chishitsu no yosoku gijutsu ni tsuite

    Aoki, K.; Inaba, T.; Shiogama, Y.; Tezuka, Y. (KajimaCorp., Tokyo (Japan))


    In order to predict precisely geological conditions ahead of a face changing with the progress of excavation work of rock caverns such as a tunnel, the drilling logging system was developed which allows to measure, store and analyze drilling data during drilling by hydraulic rotary percussion drilling machines, and the quantitative prediction of geological conditions ahead of a face was tested applying the system to a granite site. As a result, by adopting the drilling energy rate (workload per rock volume of a drilling machine during drilling) as an analytical parameter, the good correlation was found between the drilling energy rate and geological condition (rock property classification) such as a hardness of rocks and quantity of cracks. In addition, the geological condition ahead of a face was probably predictable by estimating the distribution of the drilling energy rate in a wide area by geostatistics mehtod. 5 refs., 9 figs.

  3. Noise and vibration reduction of diesel engine vehicle making use of the active control engine mount (ACM) system; Active control engine mount (ACM) wo mochiita diesel engine tosaisha no seishukusei kojo

    Aoki, K.; Hirade, T.; Hyodo, Y.; Aihara, T.; Shikata, T. [Nissan Motor Co. Ltd., Tokyo (Japan)


    An active control engine mount (ACM) system is described, which aims at reducing noise and vibration of diesel engine vehicles. ACM systems are arranged on the front and rear mounts, and reduce the noise by lowering the spring constant. The main body of an ACM system is a hydraulic mount, and is provided with a hydraulic pressure amplifier that makes use of liquid resonance, an electromagnetic actuator that converts hydraulic pressure into force, and a load sensor that detects the force that is transmitted to the vehicle body. The controller of an ACM control system feeds electric currents as needed to an actuator so as to keep the transmission of force to the minimum so that load sensor signals will be zero. The actuator employed in this report can augment the force generated there. All the parameters for the calculation model are optimized so that controllable input amplitude will increase. In the diesel engine vehicle into which ACM systems are incorporated, vibration during the idling operation is damped by approximately 10dB, the resultant vibration level as low as that of a gasoline engine vehicle. Harmonic components are also lowered in addition the second-order component. The same is true for the booming noise that is generated by a vehicle that is running, which is again damped by approximately 10dB. 2 refs., 14 figs.

  4. Solvent extraction bis (the 2- ethylhexyl) phosphoric acid catecholamine structural property quantitative correlation; Bisu (2-echiruhekishiru) rinsan wo mochiita katekoru amin rui no yobai chushutsu to teiryoteki kozo bussho sokan

    Yoshizuka, Kazuharu [Saga University, Saga (Japan); Fujimoto, Yuko; Owatari, Keisuke; Inoue, Katsutoshi


    As a basic research of separation and refinement of catecholamine (CA) by solvent extraction method which is chemical messenger of central neuron in the internal, it was extracted from dopamine (DA), adrenalin (Ad) and in hydrochloric acid aqueous solution of noradrenaline (NA). Then, each solution of chloroform. Hexane and toluene of bis (the 2 - ethylhexyl) phosphoric acid (D2EHPA) was used in respect of the stripping. All CA is CA by D2EHPA in mechanism of ion exchange: It was clarified that it was extracted as D2EHPA=1:4 complex and the extraction equilibrium constant was obtained. In addition, the consideration by molecule modeling considering the solvent effect of continuous medium types using semi-experience molecular orbital method by quantitative structural property correlation (QSPR) was carried out on got extraction equilibrium constant. (translated by NEDO)

  5. Effect of deep structure and surface layer (a) simulation study on the heavy damage belt of the 1995 Hyogoken Nanbu earthquake; Hado simulation wo mochiita `shinsai no obi` ni tsuite no kento

    Feng, S.; Ishikawa, K.; Kaji, Y. [Chuokaihatsu Corp., Tokyo (Japan)


    A simulation study was done to identify the causes for the so-called heavy damage belt observed as a result of the Hyogoken Nanbu Earthquake. This study determines distributions of the maximum amplitudes on the ground surfaces, and discusses the effects of deep structures and low-velocity surface layers, based on the simulation by the wave equation with the underground model of Higashinada-ku and its vicinity in the north-south direction, observed seismic records and artificial waves. The two-dimensional scalar wave equation is used for the analysis. The velocity structure model used for the simulation is established, based on the elastic wave seismic survey results. The focus function is drawn by expanding or contracting the time scale, using the seismic records at Kobe Port Island and artificial waves. The analysis results show that the damage belt coincides with the areas at which the focusing zone of the deep structure overlap the amplification zone in the low-velocity ground surfaces, where relative density is amplified 1.5 to 2 times. It is also observed that large peaks repeat 2 to 3 times on the time scale. 5 refs., 8 figs., 1 tab.

  6. Creation of new molecules containing threading intercalator, which can bind strongly to unusual nucleic acid structures; Nuikomigata intakareta wo mochiita tokushu RNA kozo eno tokuiteki ketsugo bunshi no shoshutsu

    Takenaka, Shigeori [Kyushu University, Fukuoka (Japan). Dept. of Chemical Systems and Engineering


    We have been studying the naphthalene diimide derivatives which can recognize the unusual nucleic acid structures due to the peculiar character of threading intercalator. Firstly, we synthesized the naphthalene diimide derivative carrying thymine moieties at the imide termini. This molecule was expected to have the preference for the non-alternating adenine sequence of single stranded nucleic acid. Circular dichroism and fluorescence energy transfer studies involving acridine orange, naphthalene diimide ligand, and d (GCGAAACGC) oligonucleotide showed that the ligand can prefer bulge form of the nucleic acid to hairpin structure. Secondly, we designed and synthesized the cyclic ligand linked between naphthalene diimide and ferrocene moieties. Cyclic ligand can strongly bind to nucleic acid base projecting out from double stranded nucleic acid such as mismatch base and this can be detected using electrochemical signal of the ligand. These ligands are not only suspected of anti-virus activity but also they are promising new probe of genetic polymorphism. (author)

  7. Method of image recognition for mixed reality. Three-dimensional position and rotation measurements using phase only correlation; Fukugo genjitsu no tame no gazo ninshiki gijutsu. Iso gentei sokan wo mochiita sanjigen buttai no ichi shisei suitei hoho

    Ito, N.


    In order to fuse a real space and a virtual space to make a mixed reality, 3-D information of object in the real space is needed. Especially, it is essential to measure the position and rotation angle of a 3-D object. There is a pattern matching algorithm called Phase Only Correlation (POC) which is able to measure the rotation angle and the position between two images. However, it is impossible to measure the rotation angle of 3-D object using POC directly, because the axis of 3-D rotation is variable. In this report, we describe the position and rotation angle measurements between two 3-D objects using POC. (author)

  8. Degradation characteristics of toxic microcystis viridis by mastigophora, monas guttula using aquatic large scale microcosm; Ogata tansui microcosm wo mochiita benmochurui monas guttula ni yoru yudoku microcystis viridis no bunkai tokusei

    Iwami, N.; Matsumura, M. [University of Tsukuba, Ibaraki (Japan); Inamori, Y. [National Inst. for Environmental Studies, Tsukuba (Japan); Sugiura, N. [Ibaraki Prefectural Waterworks, Ibaraki (Japan)


    Mastigophora, monas guttula, is able to propagate even by using large aquatic microcosm. This mastigophora efficiently predated and degraded microcystis viridis producing toxic substance, microcystin, almost in the whole quantity in the wide water temperature range from 20{degree}C to 30{degree}C at which microcystis propagates and disappears in natural lakes. As a result of evaluating perdition and degradation effects of momas guttula by chlorophyll-a and COD, any of chlorophyll-a indicated a removal rate of more than 90% almost in a week, and microcystis-origin particle COD more than 80%. It was also found that three kinds of microcystin YR, LR, and RR which microcystis viridis produces are almost completely degraded. From these results, it was thought that perdation and degradation of microfauna like m. guttula can greatly contribute to degrading and disappearing toxic microcystis even in natural lakes. 21 refs., 9 figs., 2 tabs.

  9. Injection and spray characteristics of a variable orifice nozzle applied the jerk type fuel injection pump for DI diesel engine; Jerk shiki nenryo funsha pump wo mochiita kahen funko nozzle no funsha funmu tokusei

    Hasegawa, T.; Matsui, K.; Iwasaki, T.; Kobayashi, T. [Zexel Corp., Tokyo (Japan); Matsumoto, Y. [The University of Tokyo, Tokyo (Japan)


    A Variable Orifice Nozzle (VON) by changing a cross-sectional area of the nozzle injection hole, for improving a rate of injection and injection duration, has been developed to study its injection and spray characteristics. The nozzle geometry was optimized to analyze a nozzle internal flow by computational method. Results show that, injection and spray pattern responded to the nozzle orifice cross-sectional area which is changing larger to smaller in the part load range. This results suggest to contribute a combustion improvement which decreasing NOx and soot. 14 refs., 10 figs.

  10. Estimation of water-coal surface interaction during heat treatment of coal by use of FTir and DSC; FTir to DSC wo mochiita sekitan-mizu kan sogo sayo no teiryoteki hyoka

    Miura, K.; Mae, K.; Morozumi, F.; Kusakawa, T. [Kyoto University, Kyoto (Japan)


    The authors have recently presented a method to estimate the strength distribution of hydrogen bondings in coal using FTir and DSC. The method was applied to estimate the strength of coal-water interaction in two different coals and to estimate the enthalpy change deriving from the change in hydrogen bondings during the desorption of water. The estimated enthalpy change was compared with the total enthalpy change estimated by DSC measurement to examine the importance of hydrogen bondings during the desertion of water. 1 ref., 6 figs.

  11. Earth retaining system by means of cylindrical slurry wall of high strength and high flowability concrete; Kokyodo / koryudo concrete wo mochiita enkei haku gata renzoku chichu heki ni yoru yamadome

    Nakano, M.; Tsutsumi, Y. [Tokyo Gas Co. Ltd. (Japan); Moriya, M. [Taisei Construction Co. Ltd., Tokyo (Japan)


    A LPG underground tank (60,000 cu.m, 48m in dia.) was constructed at Tsurumi ward of Yokohama city by Tokyo Gas Ltd. In advance of evacuation work, RC elements which have the highest strength in Japan were applied as connected wall for earth self-retaining. One stage of the wall (1.0m in thickness) was composed of 28 elements. In order to prevent the lifting force by the underground water against the tank bottom (design level (DL) is -32.8m), amount of permeable water from outside must be as small as possible. Owing to driving the wall into the soft bedrock by 10m, the lower end of the wall came to be DL-66m. For the purpose of estimation of permeabilities of the clay layer and the soft bedrock, simulation applying the non-stationary effective stress analysis was carried out at the time of inside draining and of excavation at intervals of 8m. Results of simulation showed that the permeabilities of the connected wall and the soft bedrock belonged to the smallest class. It is considered that the satisfactory achievement has been obtained because actual amount of gushing water has been almost constant at 6 cu.m/day. 4 refs., 8 figs., 6 tabs.

  12. Measurements of ultrasonic waves by means of laser Doppler velocimeter and an experimental study of elastic wave propagation in inhomogeneous media; Laser doppler sokudokei ni yoru choonpa keisoku to ganseki wo mochiita fukinshitsu baishitsu no hado denpa model jikken

    Nishizawa, O.; Sato, T. [Geological Survey of Japan, Tsukuba (Japan); Lei, X. [Dia Consultants Company, Tokyo (Japan)


    In the study of seismic wave propagation, a model experimenting technique has been developed using a laser Doppler velocimeter (LDV) as the sensor. This technique, not dependent on conventional piezoelectric devices, only irradiates the specimen with laser to measure the velocity amplitude on the target surface, eliminating the need for close contact between the specimen and sensor. In the experiment, elastic penetration waves with their noise levels approximately 0.05mm/s were observed upon application of vibration of 10{sup 6}-10{sup 5}Hz. The specimen was stainless steel or rock, and waveforms caught by the LDV and piezoelectric device were compared. As the result, it was found that the LDV is a powerful tool for effectively explaining elastic wave propagation in inhomogeneous media. The piezoelectric device fails to reproduce accurately the waves to follow the initial one while the LDV detect the velocity amplitude on the specimen surface in a wide frequency range encouraging the discussion over the quantification of observed waveforms. 10 refs., 7 figs.

  13. Design and construction of radiant panel for cooling and heating with photovoltaic and thermoelectric element modules; Taiyo denchi to netsuden soshi module wo mochiita fukusha reidanbo panel no sekkei oyobi shisaku

    Sato, M.; Tani, T. [Science University of Tokyo, Tokyo (Japan); Kadotani, K.; Imaizumi, H. [Komatsu Ltd., Tokyo (Japan)


    Utilizing cooling properties and current voltage characteristics of a small cooling panel using thermoelectric elements which had been fabricated previously on a trial basis, design and prototype production were executed on a large radiant cooling and heating panel driven by photovoltaic cell modules. The panel design set the cooling area to about 0.5 m {sup 2} and the number of elements to 70 pieces, and optimum number of elements in series and parallel connection was derived. As a result of the analysis, it was made clear that the optimum number of thermoelectric module arrays in series and parallel connection varies depending on insolation intensity. It was found preferable that the number of parallel connection array be set to one to two in a region or time period in which low insolation intensity is distributed in greater amount. In the case where high insolation intensity is distributed in a greater amount, setting it to two to three is preferable. By using the structured design method and the HASP Tokyo data, thermoelectric element modules were interconnected with 35 modules in series and two in parallel on a cooling panel installed on the roof of the Science University of Tokyo. A simulation result revealed that the average temperature difference on the cooled surface in summer is 4.37 degC, and the solar cell utilization rate is 0.67. It is necessary in the future to improve heat dissipation efficiency and area ratio. 1 ref., 12 figs., 5 tabs.

  14. Fundamental study on hydrogen storage with hydrogen absorbing alloys. Operating characteristics of storage tank; Suiso kyuzo gokin wo mochiita suiso chozo ni kansuru kiso kenkyu. Chozo yoki no dosa tokusei

    Sekiguchi, S.; Sekiguchi, N.; Tani, T. [Science University of Tokyo, Tokyo (Japan)


    Hydrogen absorption by a hydrogen storage (MH storage) is investigated for static characteristics, with a constant current applied to the hydrogen generator, and dynamic characteristics, with a fluctuating current applied to the same simulating actual insolation. In the experiment, alloy temperature (MH temperature) in the storage and a current for the generator are preset, and then automatic measurement is allowed to proceed at 10-second intervals of the differential pressure, hydrogen temperature in the piping, absolute pressure, MH temperature, room temperature, and water tank temperature. It is found as the result of the experiment that absorption performance is improved when the MH storage is cooled; that the mean absorption rate which is 1 without cooling increases to 1.62 at 7degC; that the mean absorption rate changes in proportion to the applied current (introduced hydrogen flow rate); that the rate which is 1 at 32A decreases to 0.53 that at 16A; that the absorption rate is dependent more on the current applied to the storage than the temperature of the heat exchanging medium; and that, even in the presence of fluctuation halfway in the applied current, the total absorption will be equal to a case of constant current application if the total amount of applied current is equal. 2 refs., 7 figs., 5 tabs.

  15. Development of emergency backup power system using photovoltaic/wind hybrid power source in unmanned relay broadcasting station; Mujin chukei hosojo ni okeru taihoko/furyoku hybrid dengen wo mochiita hijo yobi dengen system no kaihatsu. 1

    Nishikawa, S.; Takanaga, T. [Kandenko Co. Ltd., Tokyo (Japan); Sugimoto, T.; Fujiwara, S. [Japan Broadcasting Corp., Tokyo (Japan)


    An examination was made on the application of photovoltaic and wind power generation as an emergency backup power source. In this connection, the designing/manufacturing was carried out for a field demonstration test system, and also a simulation was carried out concerning the system performance. In the structure of the hybrid power source, a wind power generator is parallelly connected to a solar cell through a DC/DC converter for adjusting output voltage. It is further parallelly connected to an existing power system through a switch, supplying power to storage batteries or a broadcasting equipment. The result of the simulation revealed that, in the static characteristics, there was an output from the wind power generation if the wind velocity was 2.4m/s or above, but that a discharge from storage batteries was necessary even in the maximum performance of the wind power generation if the intensity of solar radiation was less than approximately 0.5kW/m{sup 2}. In the dynamic characteristics, an evaluation was made on the length of time of the on-load power supply after a power failure of the system in comparison with the conventional length, depending on the conditions of the wind. 2 refs., 7 figs., 1 tab.

  16. Improvement of sound qualities using simulated car interior noise. Part 2. ; Estimation by semantic differentials. Jinko AM on wo mochiita joyosha shanaion no onshitsu kaizen ni kansuru kenkyu. 2. ; SD ho ni yoru onshitsu hyoka

    Hashimoto, T.; Hatano, S. (Seikei Univ., Tokyo (Japan). Faculty of Engineering); Takao, H. (Maruyasu Industries Ltd., Aichi (Japan))


    In the present report, a method to quantitatively evaluate the roughness was proposed by using artificially prepared sound and multi-dimensionally investigating the influence of roughness, as felt, generated from amplitude-modulated sound components, on the sound quality. While evaluation method was also studied of loudness of sound, having many vectorial components in the low region, like that, used in the present experiment. The existence of amplitude-modulated sound components in the complex sound is connected to subjective feeling of uncomfort. Even without change in physical sound energy, the roughness can be lowered if amplitude-modulated sounds in two band zones are made antiphasic in phase to be synthesized. In order to measure, with a good correspondence to the loudness, complicated sound, like that, inside the car, in sound pressure level, simulation head is effectively utilized. As a physical quantity, good in correspondence to the roughness, as felt, of timewise fluctuant sound, the total of components, read in value, is so regarded in 5 to 50Hz upon a 1/3 octave analysis of effective sound pressure in timewise fluctuant component. 10 refs., 10 figs., 2 tabs.

  17. Construction of the curtain wall made of carbon fiber reinforced concrete. Sangenjaya Carrot Tower; Tanso sen`i hokyo konkurito wo mochiita katen uoru no seko - sangenjaya kyarotto tawa -

    Hara, H.; Sasaki, M.; Honda, Y. [Tokyu Construction Co. Ltd., Tokyo (Japan)


    The characteristics of the carbon fiber reinforced concrete (CFRC) for the construction of the above-titled curtain walled tower, its full-size property test and the result of building work are reported. In the beginning, the composition of CFRC materials and their blending are described and the relationship between the mixing time with a mixer destined for that purpose and the mortar flow and the quality control on the CFRC control specimens are explained, followed by a description on the CFRC weight, water content, the use of stainless reinforcement bars to suppress corrosion, dry shrinkage, the relationship between bending strength and Young coefficient, durability, the bonding state obtained by traction test and so forth, together with an outline of the test result, It is also clarified that an ultimate strength taken in member design is assumed to be the one at the moment of bending crack at a high-wind occurring once during 150 years, and the safety is assured by the reinforcement of deformed stainless bars. Further, the working steps from the form construction to the fluorocarbon resin painting are indicated enumerating requirements for the curtain wall properties in terms of water-tightness, windresisting, aseismicity and so on. Lastly, some improvements made through the experiments and the state of construction work are noted. 5 refs., 14 figs., 4 tabs.

  18. Preparation of activate carbon with high specific surface area from beer lees by chemical activation with KOH; Suisankakariumu wo mochiita yakuhin fukatsuho ni yoru birukasu karano kohihyoumenseki kasseitan no seizo

    Hayashi, J.; Kubo, A.; Furukawa, A.; Muroyama, K. [Kansai University, Osaka (Japan). Dept. of Chemical Engineering


    Activated carbons with high specific surface area were prepared from beer lees by chemical activation with KOH. We examined the influence of the preparation conditions, such as temperature and impregnation ratio, on the pore structure of the prepared activated carbon. The specific surface area increased with an increase in carbonization temperature up to 800 degree C and decreased at 900 degree C because of excess activation. It reached a maximum value at the impregnation ratio of 2.0. The activated carbon, which was prepared at the carbonization temperature of 800 degree C and at the impregnation ratio of 2.0, had very high specific surface area of 2,440 m{sup 2}/g. It was found that KOH worked effectively as the activating reagent in two temperature ranges, below 500 degree C and above 600 degree C. The amount of benzene and acetone adsorbed on the prepared activated carbon were much larger than that on the commercial activated carbons. (author)

  19. On-site processing systems for determination of the phase velocity of Rayleigh waves in microtremors using the spatial autocorrelation method; Kukan jiko sokanho wo mochiita bidochu no Rayleigh ha iso sokudo no genba kettei system

    Matsuoka, T.; Umezawa, N. [Saitama Institute of Environmental Pollution, Saitama (Japan)


    To render the spatial autocorrelation (SAC) method easier to use, a system has been constructed that can be used with ease on the site for the calculation of phase velocities. This system can perform two observation methods of the same frequency characteristics, that is, the simultaneous multi-point observation and one-point independent observation. The pickup is a velocity type seismograph of a natural period of 1 second that has been so electrically adjusted as to work on an apparent natural period of 7 seconds. Among the frequency characteristics, those related to phase are regarded as important because the SAC method is based on the measurement of coherence between two points. The analysis software runs on a waveform processing software DADiSP/WIN designed for personal computers. To know the operability of this system on the site and to accumulate records using the SAC method, observations were made at the depth of 100-500m at 6 locations in Saitama Prefecture where the underground structure was known thanks to prior PS logging. As the result, a dispersion curve was obtained by use of an array of appropriate dimensions at every location agreeing with the underground structure. 9 refs., 10 figs.

  20. Development of constructed wetland using hydroponic biofilter method for purification of hyper-eutrophic lake water; Fueiyoka kosui no joka no tameno suiko seibutsu rokaho wo mochiita jinko shicchi no kaihatsu

    Aizaki, M. [Shimane Univ., Matsue (Japan)] Nakasato, H. [Top Ecology Co. Ltd., Tokyo (Japan)


    Applying the hydroponic biofilter method as a direct purification method for a hyper-eutrophic lake water, an experiment was carried out at the Tsuchiura Port on Lake Kasumigaura to obtain data for constructing a hydrophilic artificial wetland. Purification of hyper-eutrophic lake water containing a large amount of water blooms in summer was attempted applying the hydroponic biofilter method for which hydrophyte is used. As a result, it was clarified, by applying the hydroponic biofilter method, that capturing effect of suspended substances can be achieved in the rooting zone, captured suspended substances are decomposed at high rate, and the revolved nutrient salt can be absorbed and assimilated by the use of plants having high growth rates. Ipomoea aquatica had the highest removal activity, followed by nasturtium officinal, menthe spicata, and oenanthe javanica. As a result, it became clear that a constructed wetland made with the hydroponic biofilter method can be applied as a direct purifying method for hyper-eutrophic lake water by selecting appropriate plants in accordance with season. 18 refs., 1 fig., 4 tabs.

  1. Ultimate strength analysis of thin plated structures using eigen-functions. 3rd Report. Application to reliability analysis; Koyu kansu wo mochiita usuita kozobutsu no dansosei kaisekiho. 3. Shinraisei kaiseki eno oyo

    Ueda, Y. [Osaka University, Osaka (Japan). Welding Research Institute; Masaoka, K.; Okada, H. [University of Osaka Prefecture, Osaka (Japan). Faculty of Engineering


    A reliability analysis was performed on ultimate strength of a hull by introducing reliability engineerings into the idealized structural unit method. Elements developed under the present study were applied to a model of an actual structure to indicate that even an analysis requiring much time under the finite element method can be performed in a short time and at high accuracy when this method is used. Analysis acted with bending moment and shear force simultaneously was performed on a model used as a structure in experiments carried out by Nishihara, assuming pure bending moment and longitudinal strength during slamming. Then, a reliability analysis was conducted on the same model based on this analysis method to investigate the ultimate strength. In an analysis of an ultimate strength when bending and shearing that assume slamming act upon simultaneously, axial force in the hull side decreases as loading increases, wherein how the shearing force increases can be identified clearly. Although existence of initial bends reduces the strength, the effect of variance in the vicinity of the average value on the reliability is rather small, while the effect due to variance in yield stress is greater. 27 refs., 14 figs., 4 tabs.

  2. Selective production of ricinoleic acid by hydrolysis of castor oil using lipase immobilized in N-polyisopropylacrylamide gel; Ripaze koteika N-poriisopuropiruakuriruamidogeru wo mochiita himashiyu no kasuibunaki ni yoru rishinorusan no sentakuteki seisei

    Goto, M.; Hatanaka, C.; Haraguchi, T. [Kitakyushu National College of Technology, Fukuoka (Japan)


    Lipase from Candida cylindracea or Rhizopus was immobilized in gel beads prepared by copolymerization of N-isopropylacrylamide, N-N'-methylenebisacrylamide, and acrylamide. The hydrolysis reaction of castor oil was carried out at 37 degree C by using immobilized lipase or free lipase. The optimal condition of immobilization of lipase and the productivity of ricinoleic acid is investigated. It is found that thermal inactivation of enzyme was suppressed and the formation of by-products such as estolide decreases by immobilization into the gel compared with free lipase. (author)

  3. Hybrid utilization of solar energy. Part 2. Performance analyses of heating system with air hybrid collector; Taiyo energy no hybrid riyo ni kansuru kenkyu. 2. Kuki shunetsu hybrid collector wo mochiita danbo system no seino hyoka

    Yoshinaga, M.; Okumiya, M. [Nagoya University, Nagoya (Japan)


    For the effective utilization of solar energy at houses, a heating system using an air hybrid collector (capable of simultaneously performing heat collection and photovoltaic power generation). As the specimen house, a wooden house of a total floor area of 120m{sup 2} was simulated. Collected air is fanned into a crushed stone heat accumulator (capable of storing one day`s collection) or into a living room. The output of solar cell arrays is put into a heat pump (capable of handling a maximum hourly load of 36,327kJ/h) via an inverter so as to drive the fan (corresponding to average insolation on the heat collecting plate of 10.7MJ/hm{sup 2} and heat collecting efficiency of 40%), and shortage in power if any is supplied from the system interconnection. A hybrid collector, as compared with the conventional air collector, is lower in thermal efficiency but the merit that it exhibits with respect to power generation is far greater than what is needed to counterbalance the demerit. When the hybrid system is in heating operation, there is an ideal heat cycle of collection, accumulation, and radiation when the load is light, but the balance between accumulation and radiation is disturbed when the load is heavy. 4 refs., 8 figs., 3 tabs.

  4. Study on wave power generation of electricity using torsion arc blade type horizontal axis wind turbine; Nejire enko yokugata suihei jiku fusha wo mochiita haryoku hatsuden ni kansuru kenkyu

    Kojima, N.; Kishimura, K. [Meiji University, Tokyo (Japan)


    Windmilling characteristics of a combination of a torsion arc blade type (TABT) horizontal axis wind turbine and a reverse torsion arc blade type (RTABT) horizontal axis wind turbine were evaluated in a wave activated power generation experiment. The TABT wind turbine had six blades, and the front and rear parts of the blade were twisted in the same direction, which caused the direction of rotor rotation to change as the direction of wind along the shaft changed. The RTABT wind turbine had twelve blades, and the front and rear parts of the blade were twisted reverse to each other, which allowed the direction of rotor rotation to stay constant even in the presence of wind direction reversal. To keep the direction of rotor rotation unchanged in the presence of flow direction reversal along the power generating turbine shaft, a single-stage type RTABT wind turbine and a double-stage type were used, the double-stage type being a series connection of a first-stage RTABT (for blowout and suction) and second-stage TABT (for blowout only). Both single-type and double-type rotated in the same direction irrespective of the direction of air flow. The output of the double type was obtained by adding up the values obtained from the individual turbines. The double type was two to three times higher in efficiency than the single type in turbine revolution and power output. 2 refs., 13 figs.

  5. Fault-related-folding structure and reflection seismic sections. Construction of earth model using balanced cross section; Danso ga kaizaisuru shukyoku kozo no keitai to jishin tansa danmen. 1. Balanced cross section wo mochiita chika model no kochiku

    Matsuoka, T.; Tamagawa, T. [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsukui, R. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center


    Pre-stacking depth migration treatment is studied for the estimation of the fold configuration from seismic survey cross sections. The estimation of a velocity structure is necessary for the execution of such treatment, and the utilization of structural-geological knowledge is required for its interpretation. The concept of balanced cross section in relation to the fault-bend fold constructs a stratum structure model under conditions that the deformation during fold and fault formation is a planar strain, that there is no change in volume due to deformation, and that a fold is a parallel fold. In addition to the above geometric and kinetic approach, there is another fold formation process simulation model using a Newtonian fluid for study from the viewpoint of dynamics. This simulation stands on the presumption that the boundary contains a ramp that had been in presence before fold formation and that an incompressible viscous matter is mounted on the top surface. The viscous matter flows and deforms for the formation of an anticline on the ramp. Such enables the reproduction of a fault-bend fold formation process, and helpful discussion may be furthered on the dynamic aspect of this simulation. 5 refs., 4 figs.

  6. Experimental study of lightning protection effects to a overhead ground wire by a lightning rod and projection rods; Yuraishin oyobi dosshi wo mochiita kakuchisen no raigai boshi ni kansuru jikkenteki kento

    Katsuragi, Y. [Chubu Electric Power Co. Inc., Nagoya (Japan); Aihara, Y. [Central Research Institute of Electric Power Industry, Tokyo (Japan)


    The overhead ground wire is generally used on transmission lines as one of the lightning protection devices for the power conductors. In recent years, the ground wire with an optical fiber cable in it (OPGW) has been employed on the transmission systems. The strands of the ground wire are, however, frequently melted down because of lightning strokes to them not only in summer but also in winter. For this reason, it is necessary to devise the new lightning protection method for the ground wire. As the protection method, lightning rods installed on the transmission tower arms and projection rods wound around a ground wire are proposed by authors. Lightning protection effects of these methods are shown by model experiments which simulate summer and winter lightning strokes. It has been made clear that these methods are useful as one of the lightning protection methods for transmission lines, and application conditions of them for practical use are also shown. 4 refs., 12 figs., 2 tabs.

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

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


    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.

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

    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


    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...

  9. The chemistry of ZnWO4 nanoparticle formation

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


    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...

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

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


    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.

  11. Intrinsic Defects and H Doping in WO3

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


    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

  12. Intrinsic Defects and H Doping in WO3

    Zhu, Jiajie


    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.

  13. Intrinsic Defects and H Doping in WO3

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


    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.

  14. Facile Hydrogen Evolution Reaction on WO3Nanorods

    Rajeswari Janarthanan


    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.

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

    István Székely


    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.

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

    Simpson, Stephen G.


    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...

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

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


    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.

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

    邓粲达; 林冠男; 林鸿明; 杨宗烨


    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.

  19. Electrochemical Behavior of TiO2 Nanoparticle Doped WO3 Thin Films

    Suvarna R. Bathe


    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.

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

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


    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.

  1. Charged particle response of PbWO4

    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 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

  2. Charged particle detection with PbWO4

    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

  3. Enhanced photocatalytic properties in well-ordered mesoporous WO3

    Li, Li


    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.

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

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


    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.

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

    Sun Peng; Hu Ming; Li Mingda; Ma Shuangyun


    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.

  6. Synthesis of surface sulfated BiWO with enhanced photocatalytic performance

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


    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.

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

    Jarupat Sungpanich


    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.

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

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


    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.

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

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


    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.

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

    Ng, Chai Yan [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Abdul Razak, Khairunisak, E-mail: [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: [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)


    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.

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


    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...

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

    Yin, Chao; Zhu, Shenmin, E-mail:; 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: [Shanghai Jiao Tong University, State Key Laboratory of Metal Matrix Composites (China)


    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}.

  13. Fabrication of Pd Doped WO3 Nanofiber as Hydrogen Sensor

    Alireza Nikfarjam


    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.

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

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


    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.

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

    Miyauchi, Masahiro


    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.

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

    Tatsuya Ida


    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.

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

    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: [Institute of Inorganic Chemistry, University of Cologne, Greinstrasse-6, D-50939 Cologne (Germany)


    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.

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

    Wu, Phillip M., E-mail:, E-mail:; Munakata, Ko; Hammond, R. H.; Geballe, T. H.; Beasley, M. R., E-mail:, E-mail: [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)


    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}.

  19. Eukaryotic association module in phage WO genomes from Wolbachia

    Bordenstein, Sarah R.; Bordenstein, Seth R.


    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

  20. WO3 nanotubes prepared by a coaxial electrospinning method.

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


    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.

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

    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:


    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.

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

    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)


    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)

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

    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


    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.

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

    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.


    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.

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

    Takashi Kuroki


    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.

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

    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: [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: [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)


    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.

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

    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


    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.

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

    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: [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)


    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.

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

    Ningxin eWang


    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.

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

    Wang, Li; Yan, Jiejuan; Liu, Cailong; Liu, Xizhe; Han, Yonghao, E-mail:, E-mail:; Gao, Chunxiao, E-mail:, E-mail: [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)


    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.

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

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


    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%.

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

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


    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

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

    Chakraborty, AK


    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...

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

    Zhai, Jiali; Yu, Hongwen, E-mail:; Li, Haiyan; Sun, Lei; Zhang, Kexin; Yang, Hongjun


    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.

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

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


    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

  16. Charge carriers and dc polarization phenomena in solid Na2WO4

    Bottelberghs, P.H.; Everts, E.


    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

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

    Mohite, S.V.; Rajpure, K.Y., E-mail:


    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.

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

    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: [D. Y. Patil College of Engineering & Technology, Kasaba Bawada, Kolhapur, 416006, Maharashtra (India); D.Y. Patil Medical University, Kasaba Bawada, Kolhapur, 416006, Maharashtra (India)


    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.

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

    Yijie Chen


    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.

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

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


    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.

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

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


    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

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

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


    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.

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

    Muthamizh, Selvamani; Suresh, Ranganathan; Giribabu, Krishnamoorthy; Manigandan, Ramadoss; Praveen Kumar, Sivakumar; Munusamy, Settu; Narayanan, Vengidusamy, E-mail:


    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.

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

    Takeshi Hashishin


    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.

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

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


    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.

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

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


    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

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

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


    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.

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

    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.


    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.

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

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


    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.

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

    Mourad Derbal


    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.

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

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


    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.

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

    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: [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)


    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.

  13. Charged particle response of PbWO sub 4

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


    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.

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

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


    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.

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

    He, Gang-Ling; Chen, Ming-Jie; Liu, You-Qin; Li, Xin; Liu, Ying-Ju; Xu, Yue-Hua, E-mail:


    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.

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

    Shen, Yi, E-mail:; Yan, Peng; Yang, Yali; Hu, Fengping; Xiao, Yilin; Pan, Li; Li, Zhen


    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

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

    Grivel, J. -C.


    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...

  18. Electrochromic Characterization of Electrodeposited WO3 Thin Films

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


    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.

  19. The growth of Nd:CaWO4 single crystals



    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.

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

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


    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.

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

    Aliev, Ali


    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.

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

    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: [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: [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China)


    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.

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

    Chu, Xiangfeng, E-mail: [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)


    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.

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

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


    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

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

    Cho, Young-Sik; Huh, Young-Duk, E-mail:


    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.

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


    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...

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

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


    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.

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

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


    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.

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

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


    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.

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

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


    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.

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

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


    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.

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

    涂朝阳; J.J.ROmero; 等


    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%。

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

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


    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.

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

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


    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.

  15. Piezo-optic coefficients of CaWO4 crystals

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


    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.

  16. Scheelite CaWO{sub 4} at high pressures

    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)


    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.

  17. Effect of TiO2 Nanoparticles on Photochromism of WO3 Colloids


    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.

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

    Chuan-Sheng Wu


    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.

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

    Wan, Gengping; Wang, Guizhen


    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.

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

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


    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.

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

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


    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.

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

    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)


    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.

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

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


    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.

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

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


    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

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

    Stembrowicz, W


    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.

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

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


    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.

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

    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


    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.

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

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


    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)

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

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


    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.

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

    Reyes, Karla Rosa; Robinson, David B.


    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.

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

    Song, Xu Chun, E-mail: [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)


    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.

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

    L. Norci


    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.

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

    R. Ghasempour


    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.

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

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


    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.

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

    Girish Kumar, S., E-mail:; Koteswara Rao, K.S.R., E-mail:


    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.

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


    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).

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


    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.

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

    黄世震; 林伟; 陈伟; 陈知前


    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。

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

    Yuxue Zhou


    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.

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

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


    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.

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

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


    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.

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

    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


    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.

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

    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


    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.

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

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


    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.

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

    Yong Pan


    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.

  6. CdWO4 bolometers for Double Beta Decay search

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


    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...

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

    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)


    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.

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

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


    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.

  9. 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

    陈伟龙; 沈鸿烈; 王威; 李金泽


    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.

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

    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: [Electron Microscopy for Material Science, University of Antwerp, Antwerp (Belgium)


    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.

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

    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: [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)


    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.

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

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


    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...

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

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


    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.

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

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


    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.

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

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


    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.

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

    Keereeta, Yanee [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun, E-mail: [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)


    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.

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

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


    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....

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

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


    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.)

  19. 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

    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: [Qingdao Agricultural University, Qingdao 266109 (China)


    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.

  20. 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

    ZHU Lei; MENG Zeda; OH Won-Chun


    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.

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

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


    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

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

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


    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.

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

    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: [Department of Chemistry, University of Birjand, 97175-615 Birjand (Iran, Islamic Republic of)


    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.

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

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


    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.

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

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


    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.

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

    Makgwane, PR


    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...

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

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


    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.

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

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


    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).

  9. Structural properties of WO{sub 3} dependent of the annealing temperature deposited by hot-filament metal oxide deposition

    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: [IPN, Unidad Profesional Interdisciplinaria de Biotecnologia, Av. Acueducto s/n, Col. Barrio la Laguna, 07340 Mexico D. F. (Mexico)


    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)

  10. Preparation and characterization of WO3/Bi3O4Cl nanocomposite and its photocatalytic behavior under visible light irradiation

    Chakraborty, AK


    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...

  11. Plasmodium falciparum parasites expressing pregnancy-specific variant surface antigens adhere strongly to the choriocarcinoma cell line BeWo

    Haase, Rikke N; Megnekou, Rosette; Lundquist, Maja;


    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...

  12. Facile hydrothermal synthesis of TiO2-Bi2WO6 hollow superstructures with excellent photocatalysis and recycle properties.

    Hou, Ya-Fei; Liu, Shu-Juan; Zhang, Jing-huai; Cheng, Xiao; Wang, You


    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.

  13. Physical properties characterization of WO{sub 3} films grown by hot-filament metal oxide deposition

    Diaz-Reyes, J., E-mail: [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)


    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.

  14. The band structure of WO3 and non-rigid-band behaviour in Na0.67WO3 derived from soft x-ray spectroscopy and density functional theory.

    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


    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.

  15. Preparation, structures and photoluminescent enhancement effect of PbWO4-TiO2 composite nanofilms

    Run-Ping, Jia; Guo-Xin, Zhang; Qing-Sheng, Wu


    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.

  16. Magnetic properties of KRE(WO{sub 4}){sub 2} (RE=Gd, Yb, Tm) single crystals

    Borowiec, M.T., E-mail: [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/ 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)


    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.

  17. Facile Preparation of Efficient WO3 Photocatalysts Based on Surface Modification

    Min Liu


    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.

  18. Celdas solares fotoelectroquímicas basadas en Bi2WO6

    Lorean Madriz


    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.

  19. Understanding the Potential of WO3 Based Sensors for Breath Analysis

    Staerz, Anna; Weimar, Udo; Barsan, Nicolae


    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

  20. Anomalous spin state of Fe in double perovskite oxide Sr 2FeWO 6

    Kawanaka, H.; Hase, I.; Toyama, S.; Nishihara, Y.


    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.

  1. ZnWO_4 crystals as detectors for double beta decay and dark matter experiments

    Danevich, F A; Nagorny, S S; Poda, D V; Tretyak, V I; Yurchenko, S S; Zdesenko, Y G; Zdesenko, Yu.G.


    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.

  2. ZnWO{sub 4} crystals as detectors for 2{beta} decay and dark matter experiments

    Danevich, F.A. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine)]. E-mail:; 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)


    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.

  3. Metal-insulator transition in Na{sub x}WO{sub 3}: Photoemission spectromicroscopy study

    Paul, Sanhita, E-mail:; Ghosh, Anirudha, E-mail:; Raj, Satyabrata, E-mail: [Department of Physical Sciences, Indian Institute of Science Education and Research - Kolkata, Mohanpur Campus, Nadia -741252, West Bengal (India)


    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}.

  4. Radiation-induced color centers in La-doped PbWO sub 4 crystals

    Deng, Q; Zhu, R Y


    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.

  5. Sunlight driven photocatalytic water splitting using nanostructured bismuth tungstate (Bi2WO6)

    Radha, R.; Sakar, M.; Bharathkumar, S.; Balakumar, S.


    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.

  6. Luminescence spectroscopy of K3WO3F3 oxyfluoride crystals

    Kozlov, A. V.; Pustovarov, V. A.


    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.

  7. The choriocarcinoma cell line BeWo: syncytial fusion and expression of syncytium-specific proteins.

    Orendi, Kristina; Gauster, Martin; Moser, Gerit; Meiri, Hamutal; Huppertz, Berthold


    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.

  8. Humidity sensing properties of WO{sub 3} thick film resistor prepared by screen printing technique

    Garde, Arun S, E-mail:


    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.

  9. Hot-wire chemical vapor deposition of WO{sub 3−x} thin films of various oxygen contents

    Houweling, Z. Silvester, E-mail: [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)


    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.

  10. End pumped yellow laser performance of Dy3+:ZnWO4

    Xia, Zhongchao; Yang, Fugui; Qiao, Liang; Yan, Fengpo


    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.

  11. Development of W/O Microemulsion for Transdermal Delivery of Iodide Ions

    Lou, Hao; Qiu, Ni; Crill, Catherine; Helms, Richard; Almoazen, Hassan


    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. ...

  12. An ab initio study of WO sub 3 under pressure up to 30 GPa

    Pagnier, T


    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.

  13. Study on defects associated with interstitial oxygen in PbWO4 crystal

    Liu Feng-song; Gu Mu; Zhang Rui


    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.

  14. Exposure of WO3 Photoanodes to Ultraviolet Light Enhances Photoelectrochemical Water Oxidation.

    Li, Tengfei; He, Jingfu; Peña, Bruno; Berlinguette, Curtis P


    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.

  15. Structure and morphology of laser-ablated WO{sub 3} thin films

    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)


    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.)

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

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


    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

  17. 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

    郑锋; 郭敏; 张梅


    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.

  18. Numerical simulation and experimental study of PbWO4/EPDM and Bi2WO6/EPDM for the shielding of {\\gamma}rays

    Song, Chi; Zhang, Quanping; Li, Yintao; Li, Yingjun; Zhou, Yuanlin


    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.

  19. 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

    梅长松; 钟顺和



  20. Morphology-controlled Synthesis of CdWO4 Nanocrystals%CdWO4纳米晶形貌可控合成

    杨琳琳; 王永刚; 魏超; 王玉江; 王晓峰; 徐刚; 韩高荣


    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.

  1. Novel coupled structures of FeWO4/TiO2 and FeWO4/TiO2/CdS designed for highly efficient visible-light photocatalysis.

    Bera, Sandipan; Rawal, Sher Bahadur; Kim, Hark Jin; Lee, Wan In


    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.

  2. Bifunctional MoO3-WO3/Ag/MoO3-WO3 Films for Efficient ITO-Free Electrochromic Devices.

    Dong, Wenjie; Lv, Ying; Xiao, Lili; Fan, Yi; Zhang, Nan; Liu, Xingyuan


    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.

  3. Enhanced structural and optical properties of the polyaniline-calcium tungstate (PANI-CaWO4 nanocomposite for electronics applications

    Sabu, N. Aloysius; Francis, Xavier; Anjaly, Jose; Sankararaman, S.; Varghese, Thomas


    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.

  4. Sensing performance of palladium-functionalized WO{sub 3} nanowires by a drop-casting method

    Chávez, F., E-mail: [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)


    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.

  5. Hierarchical Bi2WO6 architectures decorated with Pd nanoparticles for enhanced visible-light-driven photocatalytic activities

    Zhang, Jinniu; Chen, Tianhua; Lu, Hongbing; Yang, Zhibo; Yin, Feng; Gao, Jianzhi; Liu, Qianru; Tu, Yafang


    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.

  6. ZnWO_4 nanocrystals/reduced graphene oxide hybrids:Synthesis and their application for Li ion batteries

    WANG Xiao; LI BoLong; LIU DaPeng; XIONG HuanMing


    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%.

  7. Modification of TiO{sub 2} nanotubes by WO{sub 3} species for improving their photocatalytic activity

    Sun, Hui, E-mail:; Dong, Bohua, E-mail:; Su, Ge, E-mail:; Gao, Rongjie, E-mail:; Liu, Wei, E-mail:; Song, Liang, E-mail:; Cao, Lixin, E-mail:


    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.

  8. Reduced graphene oxide wrapped Bi2WO6 hybrid with ultrafast charge separation and improved photoelectrocatalytic performance

    Wang, Huan; Liang, Yinghua; Liu, Li; Hu, Jinshan; Cui, Wenquan


    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.

  9. Improved WO3 photocatalytic efficiency using ZrO2 and Ru for the degradation of carbofuran and ampicillin.

    Gar Alalm, Mohamed; Ookawara, Shinichi; Fukushi, Daisuke; Sato, Akira; Tawfik, Ahmed


    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.

  10. Structural phototransformation of WO{sub 3} thin films detected by photoacoustic analysis

    Pacheco, Argelia Perez, E-mail: [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)


    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.

  11. Hydrothermal synthesis of hierarchical WO{sub 3} nanostructures for dye-sensitized solar cells

    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)


    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.)

  12. WoSIS: providing standardised soil profile data for the world

    Batjes, Niels H.; Ribeiro, Eloi; van Oostrum, Ad; Leenaars, Johan; Hengl, Tom; Mendes de Jesus, Jorge


    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.

  13. Novel rib structures in Yb-doped KY(WO4)2 for laser applications

    Gardillou, F.; Borca, C.N.; Romanyuk, Y.E.; Hibert, C.; Salathé, R.P.; Pollnau, Markus


    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.

  14. Phase modification and surface plasmon resonance of Au/WO{sub 3} system

    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: [Department of Optoelectronics, University of Kerala, Kariyavattom, Thiruvananthapuram 691574, Kerala (India)


    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.

  15. Fabrication and capacitive characteristics of conjugated polymer composite p-polyaniline/n-WO{sub 3} heterojunction

    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)


    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.)

  16. Characterization of CaWO{sub 4} scintillator at room and liquid nitrogen temperatures

    Moszynski, M. [Soltan Institute for Nuclear Studies, PL 05-400 Otwock-Swierk (Poland)]. E-mail:; 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)


    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.

  17. Enhanced photocatalytic activity in anodized WO3-loaded TiO2 nanotubes

    Nazari, M.; Golestani-Fard, F.; Bayati, R.; Eftekhari-Yekta, B.


    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.

  18. On the nature of the WO3 star DR1 in IC 1613

    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


    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.

  19. Alkali-Phosphate Glasses Containing WO3 and Nb2O5

    L. Bih


    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.

  20. Electrochemical Performance of Morphologically Different Bi2WO6 Nanostructures Synthesized via a Hydrothermal Route

    Wang, Fei; Yang, Hua; Zhang, Haimin; Su, Junyan; Wang, Xiangxian


    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.

  1. Hydrothermal Synthesis and Ammonia Sensing Properties of WO3/Fe2O3 Nanorod Composites

    Dien, Nguyen Dac; Phuoc, Luong Huu; Hien, Vu Xuan; Vuong, Dang Duc; Chien, Nguyen Duc


    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.

  2. Electrical conductivity and defect chemistry of PbMoO4 and PbWO4

    Groenink, J.A.; Binsma, H.


    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

  3. Ultrasmall Biocompatible WO3- x Nanodots for Multi-Modality Imaging and Combined Therapy of Cancers.

    Wen, Ling; Chen, Ling; Zheng, Shimin; Zeng, Jianfeng; Duan, Guangxin; Wang, Yong; Wang, Guanglin; Chai, Zhifang; Li, Zhen; Gao, Mingyuan


    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.

  4. Characterization of MeWO 4 (Me = Ba, Sr and Ca) nanocrystallines prepared by sonochemical method

    Thongtem, Titipun; Phuruangrat, Anukorn; Thongtem, Somchai


    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.

  5. Raman signatures of charge ordering in K0.3WO3

    Sagar, D. M.; Fausti, D.; van Smaalen, S.; van Loosdrecht, P. H. M.


    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

  6. Synthesis of wo3 nanogranular thin films by hot-wire CVD

    Houweling, Z.S.; Geus, J.W.; Schropp, R.E.I.


    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


    Durán Sánchez, Amador


    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."

  8. Thermally induced evolution of sol–gel grown WO3 films on ITO/glass substrates

    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.


    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

  9. Growth of NaBi(WO4)2 Dendrite and Mechanism

    HONG Yong; AI Fei; PAN Xiu-Hong; JIN Wei-Qing; ZHONG Wei-Zhuo; SHINICHI Yoda


    @@ 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.

  10. A MEMS-based Benzene Gas Sensor with a Self-heating WO3 Sensing Layer

    Lung-Ming Fu


    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.

  11. Microstructural and Mechanical Studies of PVA Doped with ZnO and WO3 Composites Films

    N. B. Rithin Kumar


    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.

  12. Nanostructure and Formation Mechanism of PtWO3/C Nanocatalyst by Ethylene Glycol Method

    WU Feng; LIU Yanhong; WU Chuan


    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.

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

    Chien Chon Chen


    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.

  14. Synthesis, characterization and photocatalytic activity of porous WO{sub 3}/TiO{sub 2} hollow microspheres

    Yang, Liuyang [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Si, Zhichun, E-mail: [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)


    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.

  15. Phase relations and chemical vapor transport of hexagonal indium tungsten bronze In{sub x}WO{sub 3}

    Steiner, Udo, E-mail:


    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)

  16. Preparation of three dimensional graphene foam–WO{sub 3} nanocomposite with enhanced visible light photocatalytic activity

    Azimirad, R., E-mail:; Safa, S.


    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.

  17. 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

    袁媛; 张军营; 樊国祥; 赵永椿; 郑楚光


    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.

  18. 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

    杨海刚; 宋桂林; 张基东; 王天兴; 常方高


    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.

  19. Quantum dots as mediators in gas sensing: A case study of CdS sensitized WO3 sensing composites

    Concina, Isabella; Comini, Elisabetta; Kaciulis, Saulius; Sberveglieri, Giorgio


    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.

  20. On the low-lying states of WO - A comparison with CrO and MoO

    Nelin, C. J.; Bauschlicher, C. W., Jr.


    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.

  1. Growth,structural,thermal properties and spectroscopic characteristics of KTb(WO4)2 single crystal

    LI Jing; WANG Jiyang; HAN Shujuan; GUO Yongjie; WANG Yongzheng


    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.

  2. Electrochemical and electrochromic properties of layer-by-layer films from WO(3) and chitosan.

    Huguenin, Fritz; Gonzalez, Ernesto R; Oliveira, Osvaldo N


    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.

  3. Study of Hydrogen Adsorption on Pt/WO3-ZrO2 through Pt Sites

    Sugeng Triwahyono; Aishah Abdul Jalil; Hideshi Hattori


    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.

  4. Preparation of ultra-thin and high-quality WO3 compact layers and comparision of WO3 and TiO2 compact layer thickness in planar perovskite solar cells

    Zhang, Jincheng; Shi, Chengwu; Chen, Junjun; Wang, Yanqing; Li, Mingqian


    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.


    何延春; 邱家稳



  6. 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

    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...

  7. Synthesis and characterization of F-doped Cs0.33WO3-xFx particles with improved near infrared shielding ability

    Liu, Jingxiao; Luo, Jiayu; Shi, Fei; Liu, Suhua; Fan, Chuanyan; Xu, Qiang; Shao, Guolin


    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.

  8. Forskolin-induced differentiation of BeWo cells stimulates increased tumor growth in the chorioallantoic membrane (CAM) of the turkey (Meleagris gallopavo) egg.

    Schneider, Ralf; Borges, Marcus; Kadyrov, Mamed


    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.

  9. Preparation of Ag/Bi2 WO6 and Photocatalysis Oxidation Property%Ag/Bi2 WO6的制备及光催化氧化性能

    杨芬; 朱勋乐


    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.

  10. Pd Nanoparticles Coupled to WO 2.72 Nanorods for Enhanced Electrochemical Oxidation of Formic Acid

    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)


    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.

  11. Enhanced Colouration Efficiency of Pulsed DC Magnetron Sputtered WO3 Films Cycled in H2SO4 Electrolyte Solution

    K. Punitha


    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.

  12. One-dimensional Z-scheme TiO2/WO3/Pt heterostructures for enhanced hydrogen generation

    Gao, Hongqing; Zhang, Peng; Hu, Junhua; Pan, Jimin; Fan, Jiajie; Shao, Guosheng


    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.

  13. CTAB-Assisted Hydrothermal Synthesis of WO3 Hierarchical Porous Structures and Investigation of Their Sensing Properties

    Dan Meng


    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.

  14. Electrosprayed heterojunction WO3/BiVO4 films with nanotextured pillar structure for enhanced photoelectrochemical water splitting

    Mali, Mukund G.; Yoon, Hyun; Kim, Min-woo; Swihart, Mark T.; Al-Deyab, Salem S.; Yoon, Sam S.


    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.

  15. Structural and optical modifications of the Ag2WO4/CoPc nanocomposite for potential applications

    Sreedevi, A.; Priyanka, K. P.; Babitha, K. K.; Jaseentha, O. P.; Varghese, Thomas


    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.

  16. Saucer-and Rod-like WO_3 3-D Microstructures:Synthesis,Characterization,and Optical Properties

    CHEN Lin; YAN Ting-Jiang; ZHENG Jing; LI Li-Ping


    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.

  17. Convenient synthesis of twin-Christmas tree-like PbWO4 microcrystals and their photocatalytic properties

    Zhang, Jin; Peng, Li-Li; Tang, Ying; Wu, Huijie


    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.

  18. Correction: Iron-doping-enhanced photoelectrochemical water splitting performance of nanostructured WO3: a combined experimental and theoretical study.

    Zhang, Teng; Zhu, Zonglong; Chen, Haining; Bai, Yang; Xiao, Shuang; Zheng, Xiaoli; Xue, Qingzhong; Yang, Shihe


    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.

  19. Effect of Oral Administration of Tungsten Trioxide (WO3) Particles on Hispathological Feature of liver and kidney in Rat

    Munawaroh, H. S. H.; Nandiyanto, A. B. D.; Gumilar, G. G.; Widi, A.; Subangkit, M.


    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.

  20. Hollow Sodium Tungsten Bronze (Na0.15WO3) Nanospheres: Preparation, Characterization, and Their Adsorption Properties

    Zuo Guanke; Guo He; Liu Hui; Zhang Jingyan; Hou Jing; Shen Guangxia; Cheng Ping; Guo Shouwu


    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

    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


    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

    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)


    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

    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)


    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

    F B Xiong; H F Lin; L J Wang; H X Shen; Y P Wang; W Z Zhu


    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

    WANG Cheng; FAN Li; ZHANG Shu-Yi; YANG Yue-Tao; ZHOU Ding-Mao; SHUI Xiu-Ji


    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. Hydrothermal deposition and photochromic performances of three kinds of hierarchical structure arrays of WO{sub 3} thin films

    Ding, Defang; Shen, Yi, E-mail:; Ouyang, Yali; Li, Zhen


    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.

  7. CdWO{sub 4}-on-MEH-PPV:PS as a candidate for real-time dosimeters

    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: [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil)


    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.

  8. Hydrothermal synthesis of a novel BiErWO{sub 6} photocatalyst with wide spectral responsive property

    Zhang, Zhijie, E-mail: [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)


    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.

  9. Graphitic g-C{sub 3}N{sub 4}-WO{sub 3} Composite: Synthesis and Photocatalytic Properties

    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)


    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.

  10. Nanospherical composite of WO3 wrapped NaTaO3: Improved photodegradation of tetracycline under visible light irradiation

    Qu, Lingnan; Lang, Junyu; Wang, Shuwei; Chai, Zhanli; Su, Yiguo; Wang, Xiaojing


    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.

  11. Atomic layer deposition of diisopropylaminosilane on WO3(001) and W(110): a density functional theory study.

    Lee, Kyungtae; Lee, Woojin; Lee, Hyo Sug; Shin, Jaikwang; Park, Jieun; Lee, Seongsuk; Choi, Samjong; Kim, Sueryeon; Kim, Jinseong; Shim, Youngseon


    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.

  12. Facile synthesis of 2-D Cu doped WO3 nanoplates with structural, optical and differential anti cancer characteristics

    Mehmood, Faisal; Iqbal, Javed; Gul, Asma; Ahmed, Waqqar; Ismail, M.


    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.

  13. Photocatalytic activity of Pt-modified Bi{sub 2}WO{sub 6} nanoporous wall under sunlight

    Yu, Ya-Nan; Lu, Shi-Yu; Bao, Shu-Juan, E-mail: [Southwest University, Faculty of Material & Energy, Institute for Clean Energy & Advanced Materials (China)


    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.

  14. Enhanced photocatalytic degradation of methyl orange by CdS quantum dots sensitized platelike WO3 photoelectrodes

    文瑾; 刘灿军; 杜勇; 胡传跃; 田修营


    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.

  15. WO3 Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates.

    Choi, Seon-Jin; Kim, Sang-Joon; Cho, Hee-Jin; Jang, Ji-Soo; Lin, Yi-Min; Tuller, Harry L; Rutledge, Gregory C; Kim, Il-Doo


    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.

  16. Synthesis of bismuth tungstate (Bi{sub 2}WO{sub 6}) nanoflakes and their field emission investigation

    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: [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)


    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.

  17. 纳米WO_3/玻璃薄膜光催化性能研究%Photocatalysis Performance of Nano-WO_3/Glass Thin Film

    吴永健; 张果龙


    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.

  18. Synthesis of TiO2/WO3 nanoparticles via sonochemical approach for the photocatalytic degradation of methylene blue under visible light illumination.

    Anandan, Sambandam; Sivasankar, Thirugnanasambandam; Lana-Villarreal, Teresa


    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.

  19. A significant cathodic shift in the onset potential and enhanced photoelectrochemical water splitting using Au nanoparticles decorated WO3 nanorod array.

    Xu, Fang; Yao, Yanwen; Bai, Dandan; Xu, Ruishu; Mei, Jingjing; Wu, Dapeng; Gao, Zhiyong; Jiang, Kai


    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.

  20. HT-solution growth and characterisation of InxNaxMn1-2xWO4 (0

    Gattermann, U.; Park, S.-H.; Paulmann, C.; Benka, G.; Pfleiderer, C.


    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.

  1. Synthesis of multiple-shell WO3 hollow spheres by a binary carbonaceous template route and their applications in visible-light photocatalysis.

    Xi, Guangcheng; Yan, Yan; Ma, Qiang; Li, Junfang; Yang, Haifeng; Lu, Xiaojing; Wang, Chao


    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.

  2. Fiscal 1998 achievement report on regional consortium research and development project. Venture business raising type regional consortium - small business creating base type (Research and development of Peltier actuating device-aided advanced medical and welfare systems - 2nd year); 1998 nendo Peltier undo soshi wo mochiita kodo iryo fukushi system no kenkyu kaihatsu seika hokokusho. 2



    Efforts are made to develop a new Peltier actuating device by amalgamating a Peltier device and shape memory alloy and to apply the product to medical and welfare activities. In the development of active movement control for a Peltier actuating device, a multiaxial control system is developed, and a success is attained in high-speed and high-precision control of temperature and in current- and voltage-aided control of the behavior. In the development of an active actuator for catheters, an active catheter is developed for the first time, capable of performing twisting and bending simultaneously. In the development of an artificial heart catheter, an approximately 10cm-long Peltier actuating device is manufactured to serve as an artificial heart module, and a controller is developed to drive the module at the frequency of approximately 0.5Hz. In the development of shape memory alloys and Peltier devices for normal temperature actuation, the impact is examined of the addition of a third element on the transformation temperature and shape memory characteristics. Research and development is also carried out for element technologies for using a Peltier actuating device as an artificial muscle. (NEDO)

  3. In situ observation of surface reactions with synchrotron radiation induced semiconductor processes by infrared reflection absorption spectroscopy using buried metal layer substrates; Umekomi kinzokuso kiban wo mochiita sekigai hansha kyushu supekutoruho ni yoru hoshako reiki handotai process hanno no sonoba kansatsu

    Yoshigoe, A.; Hirano, S. [The Graduate University for Advanced Studies, Yokohama (Japan); Mase, K.; Urisu, T. [Institute for Molecular Science, Aichi (Japan)


    It is known that infrared reflection absorption spectroscopy (IRAS) on semiconductor or insulator surfaces becomes practicable by using buried metal layer (BML) substrates, in which the metal thin film is buried order semiconductor or insulator films. In this work, IRAS has been measured for Langmuir-Blodgett films deposited on the BML substrate with SiO2/Al/Si(100) structure and the observed spectrum intensity has been quantitatively compared with the calculation assuming the ideal multilayer structure for the BML substrate. The BML-IRAS using CoSi2 has been adopted to the detection of SiHn on the Si (100) substrate during synchrotron radiation (SR) stimulated Si2H6 gas source molecular beam epitaxy. It has been found that SiH2 and SiH3 on the Si (100) surface are easily decomposed by SR, but SiH can`t be decomposed. From these experiments, it has been concluded that the BML-IRAS is an useful in situ observation technique for the photo-stimulated surface reactions. 26 refs., 9 figs.

  4. Theoretical study on instability mechanism of jet-induced sloshing. Model development using Orr-Sommerfeld equation generalized for non-parallel flow; Funryu reiki sloshing gensho no hassei kiko ni kansuru rironteki kenkyu. Hiheiko nagare ni ippankashita Orr-Sommerfeld hoteishiki wo mochiita model ka

    Eguchi, Y. [Central Research Institute of Electric Power Industry, Tokyo (Japan)


    A theoretical model was developed to study the mechanism of free surface sloshing in a vessel induced by a steady vertical jet flow. In the model, jet deflection is calculated with eigen values of the generalized Orr-Sommerfeld equation which is applicable to slightly non-parallel jet. Instability criteria employed in the model are (1) resonace condition between sloshing and jet frequencies and (2) {pi} phase relation between jet displacement at an inlet and global jet deflection. Numerical results of the mathematical model have shown good agreement with experimental ones, which justifies that the inherent instability of free jet itself and edge tone feedback are the main causes of the self-excited sloshing. 9 refs., 10 figs.

  5. Development of base isolation system for earthquakes and micro-vibrations using laminated thick rubber bearings part 1. ; Characteristics tests for laminated thick rubber bearings. Atsuniku sekiso gomu wo mochiita menshinter dot joshin system no kaihatsu 1. ; Atsuniku sekiso gomu no tokusei shiken

    Nakamura, T.; Okada, H.; Seki, m.; Sugiyama, K.; Teramura, A.; Uchida, H. (Obayashi Corp., Tokyo (Japan))


    Natural rubber type thick laminated rubber bearings being dynamically investigated in order to be adopted to the base isolation system from the traffic and seismic vibrations, experiment was made to contribute to the design. Used were two test models, about 5Hz in natural frequency in the vertical direction. One was designed to support 35t and the other was done to do 200t. As a result, the thick laminated rubber bearing, differently from the conventional thin one, is comparative large in influence of input force vibration frequency, deformation amplitude, axial load, etc. on the dynamic characteristics in both the horizontal and vertical directions, and its dynamic horizontal rigidity varies in a range, 0.6 to 1.45 times as high as the static one, as standardized under the designed axial load condition. The dynamic vertical rigidity of thick laminated rubber bearing at the natural frequency in the vertical direction under the designed axial load condition was also confirmed to be about 30 to 40% higher than the static one, as standardized under the same load condition. Both the thick and thin bearingsare equally assured of about 1 to 2% in equivalent viscosity damping constant. The alteration in characteristics, corresponding to a secularity for 60 years, as investigated by heating deterioration test showed a heightening by about 15 to 20% in both horizontal and vertical rigidities. 5 refs., 29 figs., 3 tabs.

  6. Development of base isolation system for earthquakes and micro-vibrations using laminated thick rubber bearing Part 2. ; Vertical damper device and its dynamic characteristics. Atsuniku seiso gomu wo mochiita menshinter dot joshin system no kaihatsu 2. ; Jogeyo damper no kaihatsu to sono dotokusei

    Teramura, A.; Yoshihara, J.; Nakamura, M.; Nakamura, T.; Yasui, Y. (Obayashi Corp., tokyo (Japan))


    In case of adopting thick laminated rubber bearing to the base isolation system to reduce earthquake forces, it is necessary to equip it with a vertical damper system in order to supplement the low damping characteristics. A damper system was then developed to be structured of plural cylindrical steel pipes, different in diameter, and high viscosity silicon material injected thereinto. Together with introducing that damper system in summary and simultaneously showing it in method to calculate the damping force, the present report further explained result of verification test, performed by an installed base-isolated building. As a result of analyzing test result, upon calculating/deriving the damper in damping force with the frequency and deformation dependency, taken into consideration as proper to viscous fluid material, correspondence was confirmed to almost cover a vibration range of micronm to mm. Also by horizontal input force test, it was confirmed for the moving joint of damper to follow the large horizontal deformation. As a result of enforced vibration test on a 140t weight base-isolated building, equiped with thick laminated rubber bearings and installed with a vibrator, damping performance was shown to almost correspond to its designed initial value. 11 figs., 2 tabs.

  7. Development of base isolation system for earthquakes and micro-vibrations using laminated thick rubber bearings. Part 3. ; Application to a medical facility building subjected to railway-induced vibration. Atusniku sekiso gum wo mochiita senshinter dot joshin system no kaihatsu. 3. ; Densha shindo ni taisuru sentan iryo shisetsu no joshin

    Teramura, A.; Yoshihara, J.; Nakamura, M.; Ishikawa, R.; Yasui, Y.; Suzuki, T.; Okada, H (Obayashi Corp., Tokyo (Japan))


    A base isolation system using laminated thick rubber bearings was developed aiming for isolation of not only earthquake vibrations, but also railway-induced micro-vibrations. This system was applied to a medical facility building in which several sets of high-technology equipment, such as a medical small cyclotron and a position emitting computed tomography, were installed. The building was constructed at a site adjacent to a railway. In the design of the base isolation system for earthquakes, the dynamic-response analysis was done for recorded and simulated vibrations of earthquakes. For the micro-vibrations, effects of the railway-induced vibration on the base of the site were surveyed beforehand, and then the extensive base isolation system including foundation was investigated, in which an application of laminated thick rubber bearings and development of effective dampers to vertical vibrations were important subjects. Measurements done for the railway-induced micro-vibrations when the building frame was completed, showed that the ground surface vibration at a level from 40 to 50 gal was reduced toa level less than 1 gal on the building floor, and the appropriateness of the design technique and the effectiveness of the system against micro-vibrations were confirmed. 5 refs., 20 figs., 3 tabs.

  8. Improvement of the bonding strength of Al/Cu transition joint made by single-shot explosive welding technique using Cu intermediate plate. Cu chukanzai wo mochiita doji bakusetsuho ni yoru Al/Cu izai tsugite no setsugo kyodo no kaizen

    Izuma, T.; Niwatsukino, T. (Asahi Chemical Industry Co. Ltd., Tokyo (Japan)); Hokamoto, K.; Fujita, M. (Kumamoto University, Kumamoto (Japan))


    Improvement of the bonding strength of Al/Cu transition joints was tried by single-shot explosive welding technique using a Cu intermediate plate (Cu-IP). As the preliminary experiment, a relatively thin Al alloy plate (4 mm in thickness) and Cu plate (2.5 mm) were bonded by explosive welding to study the effect of bonding conditions on interfacial zone (IZ) structure and bonding strength. As a result, the thickness of IZs increased with an explosive mass involving reduction of bonding strengths, and the use of Cu-IP was effective in reducing the energy applied to IZ because the energy contributed to formation of IZ. As the fabrication experiment of practical Al/Cu transition joints, a pure Al plate and pure Cu plate of 20 mm in thickness and Cu-IPs of 1.0 and 1.5 mm were bonded by explosive welding. As a result, the IZ thickness was 20-70 [mu]m and 5 [mu]m without/with Cu-IP, respectively, and the joint showed the same tensile strength as the base Al plate, suggesting possible production of practical Al/Cu electrical transition joints. 8 refs., 12 figs., 3 tabs.

  9. Estimation of underground structure using phase velocities of Love-and Rayleigh-waves from three-component microtremor array observation at Morioka city; Moriokashi ni okeru sanseibun are bido kansoku ni yoru reiri-ha rabu-ha no ryoiso sokudo wo mochiita chika kozo suitei

    Yamamoto, Hidekazu; Saito, Tokumi; Ohashi, Hiromasa [Iwate University, Iwate (Japan)


    In conventional microtremor prospecting methods, underground structure is estimated using the phase velocity of Rayleigh-wave only. However, it is considered that the underground structure can be estimated at a higher accuracy by using two phase velocities of Rayleigh-wave and Love-wave that directly reflects S-wave velocity structure. Therefore, three-component microtremor array observation of a circle (equilateral triangle) with the maximum radius of 40 to 250 m was carried out at the center of Morioka city. Analysis was carried out by means of extended space with autocorrelation to obtain phase velocities of Love- and Rayleigh-waves. The frequency zone of the obtained Rayleigh-wave phase velocity is 1.5 Hz to 8.6 Hz, and the phase velocity is 2670 m/s to 733 m/s. The frequency zone of the obtained Love-wave phase velocity is 3 Hz to 8.6 Hz, and the phase velocity is 2100 m/s to 412 m/s. The underground structure obtained by using two observed phase velocities is clarified under a depth of 116 m. A stratum deemed to be the basement exists from a depth of 21 m (Vs=1100 m). As a result, the underground structure can be estimated at a higher accuracy if two phase velocities of Love-and Rayleigh-waves are used. (translated by NEDO)

  10. Evaluation of dynamic properties of soft ground using an S-wave vibrator and seismic cones. Part 2. Vs change during the vibration; S ha vibrator oyobi seismic cone wo mochiita gen`ichi jiban no doteki bussei hyoka. 2. Kashinchu no Vs no henka

    Inazaki, T. [Public Works Research Institute, Tsukuba (Japan)


    With an objective to measure a behavior of the surface ground during a strong earthquake directly on the actual ground and make evaluation thereon, a proposal was made on an original location measuring and analyzing method using an S-wave vibrator and seismic cones. This system consists of an S-wave vibrator and a static cone penetrating machine, and different types of measuring cones. A large number of measuring cones are inserted initially in the object bed of the ground, and variation in the vibration generated by the vibrator is measured. This method can derive decrease in rigidity rate of the actual ground according to dynamic strain levels, or in other words, the dynamic nonlinearity. The strain levels can be controlled with a range from 10 {sup -5} to 10 {sup -3} by varying the distance from the S-wave vibrator. Furthermore, the decrease in the rigidity rate can be derived by measuring variations in the S-wave velocity by using the plank hammering method during the vibration. Field measurement is as easy as it can be completed in about half a day including preparatory works, and the data analysis is also simple. The method is superior in mobility and workability. 9 figs.

  11. Elucidation of hydrogen mobility in tetralin under coal liquefaction conditions using a tritium tracer method. Effects of the addition of H2S and H2O; Tritium tracer ho wo mochiita sekitan ekika hanno jokenka deno tetralin no suiso idosei hyoka. Ryuka suiso oyobi mizu no tenka koka

    Kanbe, M.; Saito, M.; Ishihara, A.; Kabe, T. [Tokyo University of Agriculture and Technology, Tokyo (Japan)


    It was previously reported that the tritium tracer method is useful for the quantitative consideration of hydrogen behavior in coal during coal liquefaction reaction. Tetralin is excellent hydrogen donating solvent, and is considered as one of the model compounds of coal. In this study, effects of H2S and H2O on the hydrogen exchange reaction between tetralin and gaseous hydrogen labeled by tritium were investigated. It was suggested that the conversion of tetralin and the hydrogen exchange reaction between gaseous hydrogen and tetralin proceed through the radical reaction mechanism with a tetralyl radical as an intermediate product. When H2S existed in this reaction, the hydrogen exchange yield increased drastically without changing the conversion yield. This suggested that the hydrogen exchange reaction proceeds even in the reaction where radical does not give any effect. In the case of H2O addition, the conversion yield and hydrogen exchange rate decreased into a half or one-third. It was suggested that H2O inhibited the formation process of tetralyl radical. 6 refs., 4 figs.

  12. Achievement report for fiscal 1998 on area consortium research and development business, 1st year. Area consortium energy research and development (molding material processing eco-system using powder lubricant); 1998 nendo chiiki consortium energy kenkyu kaihatsu bun'ya. Funtai rikei junkatsuzai wo mochiita sokeizai kako eko system no kenkyu kaihatsu (dai 1 nendo)



    A material processing technology demanding but low energy and cost and causing low environmental impact was developed using a powder lubricant in a closed metal die system. An inorganic powder excellent in adhesiveness as lubricant was discovered. Powder lubricants for die casting and new carbon lubricants for metal die forging were also developed. In a test in an eco-die casting system, it was found that power was better than water solution in terms of finish and energy efficiency. In the development of a metal forging system using a powder lubricant, existing graphite lubricants and new powder lubricants containing fullerene were subjected to evaluation (ring tests). Two types of graphite solutions now in use and two powder lubricants were evaluated by the ring tests, and this enabled the comprehension of powder lubricant characteristics. For the development of a die casting system requiring no lubricant, a metal die surface treatment method was found that produces a surface excellent in resisting erosion by the application of the aluminizing ion nitriding composite treatment method. In addition, wettability was compared between a PVD (physical vapor deposition)-formed nitride film and the powder lubricant constituents. The report also refers to surveys conducted for commercialization. (NEDO)

  13. Prediction of capacity of heat exchanger by thermal network method. Prediction of a capacity of a condenser with effective specific heat model; Netsukairomoho ni yoru kuki chowayo netsukokanki seino no yosoku. Yukohi netsu model wo mochiita gyosukukuki seino no o yosoku

    Kaga, K.; Yamada, K.; Koto, S.; Ogushi, T. [Mitsubishi Electric Corp. Tokyo (Japan)


    In this paper, thermal network method using effective specific heat model of refrigerant with phase change is proposed for predicting the capacity of a plate fin and tube type heat exchanger. Effective specific heat model suits for obtaining an accurate result of a heat exchanging capacity of a condenser with small number of elements. By comparing calculated results with experiment, it is clarified that an error of calculated capacity of condenser is less than 1% in case that the range of sub-cool degree is from 15K to 22K at outlet of refrigerant flow. (author)

  14. Push-pull type of high-frequency inverter with voltage controllability by using short-circuit mode and its application to high-frequency lighting circuit of electric-discharge lamp. Tanraku modo wo mochiita kaseigyo push pull koshuha inverter to hoden ranpu koshuha tento kairo eno oyo

    Funabiki, S.; Komatsubara, H. (Okayama Univ., Okayama (Japan)); Kanbara, T.; Tanigawa, K. (Matsushita Electric Works Ltd., Osaka (Japan))


    In recent years, in order to compact the inverter and to make high-function of the inverter used in electric-discharge lamp, the electronic-inverter with high-frequency is improved. There are some problems in the high-frequency inverter that surge and noise occur when switch loss increases and voltage is intermitted abruptly that is caused by the over-voltage at the time of turn-on and turn-off. In this paper, as for voltage resonant type of push-pull high-frequency inverter circuit, a control method using a short-circuit mode actively that turns 2 switches on at the same time in power output control is proposed and the theoretical analysis and practical experiments are carried out. Then, the application of the control method to electric-discharge lamp is studied. As for the comparison of the steady-state characteristics of theoretical analysis with the experiment data, the result shows the both agrees well with each other even though there are some errors caused by the parasitic capacity of the MOSFET being a switch of the circuit. And, a stable output control in a wide range is achieved based on the experiments of the lighting circuit of the electric-discharge lamp. 7 refs., 7 figs., 3 tabs.

  15. Enhancement of evaporation of droplet using EHD effect. 2nd Report. ; Onset of instability of gas-liquid interface under electric field. EHD koka wo mochiita ekiteki no johatsu sokushin. 2. ; Denba no moto deno kieki kaimen no fuantei gensho ni tsuite

    Takano, K.; Tanasawa, I.; Nishio, S. (tokyo University, Tokyo (Japan). Institute of Industrial Science)


    Evaporation is accelerated when an electric field is applied to droplets evaporating in a spheroid condition. To identify the correlation with an liquid column generated at the bottom of the droplet in the accelerated evaporation, experiments and analyses were carried out by applying electric fields onto horizontal free surfaces of several kinds of liquid. The minimum voltage (critical voltage) at which a turbulence occurs on the free liquid surface can be analyzed as a stability problem on the interface turbulence when pressure, gravitational force, surface tension and electrical power act upon the two-dimensional horizontal free liquid surfaces. From the fact that the critical voltage analytic values on the unstable generation agree well with the experimental results, this analytic method was expanded and calculated to predict the upper limit of the evaporation accelerating temperature (the heat transfer face temperature at which the unstable turbulence wavelength becomes equal to the droplet's bottom diameter) when an electric field is applied to droplets generating in the spheroid condition. The analysis agreed with the experimental result qualitatively. Therefore, the solid-liquid contact in a liquid column that is generated when an electric field is applied to droplets evaporating in a spheroid condition suggests a close correlation with the interface instability. 15 refs., 13 figs., 1 tab.

  16. Development of a new numerical method for visco-elastic flows using the GSMAC-method and the MUSCL-TVD method. Flows of Maxwell fluid through planer abrupt contraction; Kosei hoteishiki ni TVD gata MUSCL ho wo mochiita GSMAC ho ni yoru nendansei ryutai no kaiseki ni tekishita scheme kaihatsu. Maxwell ryutai no kyushuku shoheibannai nagare ni yoru kensho

    Fujieda, T.; Tanahashi, T.; Okada, A. [Keio University, Tokyo (Japan). Faculty of Science and Technology; Kato, Y. [Asahi Glass Co. Ltd., Tokyo (Japan)


    In this paper, we propose a new GSMAC-FEM (generalized simplified marker and cell-finite element method) which is suited to the numerical analysis of visco-elastic fluids. The equation of continuity and the equation of momentum are solved by the GSMAC-FEM algorithm and the constitutive equation is solved by the finite volume method. This scheme employs the third order MUSCL (Monotone Upstream-centered Schemes for Conservation Law) in order to guarantee the absence of spurious oscillation near the steep gradients of the variable. This method uses a minmod limiter in order to satisfy the TVD (Total Variation Diminishing) condition. The present method employs the simultaneous relaxation of velocity and pressure for the incompressible condition. The flows of Maxwell fluid through two-dimensional planer abrupt contraction are calculated by the present method and the effects the Weissenberg number and the Reynolds number are discussed. 13 refs., 12 figs.

  17. FY 1998 results of the regional consortium R and D project/the venture promotion type regional consortium R and D (small-/medium-size venture creation type). Development of a new X-ray wavelength-modulated diffraction system; 1998 nendo hacho henco kaisetsuho wo mochiita shin x sen kaisetsu hochi no kaihatsu seika hokokusho



    In the wavelength-modulated X-ray diffraction method, noting that synchrotron radiation (SR) is a high luminance white light with the continuous wavelength distribution, the Blagg refection from crystals is recorded by continuously changing the wavelength. The paper described the results of the development. The camera distance/diameter were made variable in connection with the wavelength modulation. By expanding the area (enlargement of screen) of imaging plate (IP) by Weissenberg camera method, the number of diffraction dots increased, and the data on wavelength gradient were made exact. The camera was completed as designed by introducing X-ray beams, adjusting collimator, specimens, and position of IP. The concentrating mirror device is integrated into the beam line of the SR center, and mirror effects were confirmed through the actual synchrotron radiation. The function of wavelength modulation of double crystal spectrometer was also confirmed. Two kinds of ferrocene derivatives were synthesized of which the wavelength modulation effect is expected as specimen for functional test. Monocrystals were successfully raised, and measured by wavelength-modulated X-ray diffraction device. The validity of phase determination function of the developmental device was confirmed with the results of the existing structure analysis as reference. (NEDO)

  18. In-situ testing of the liquefaction potential of soft ground using an s-wave vibrator and seismic cones. Part 1. System, concept and preliminary test result; S ha vibrator oyobi seismic cone wo mochiita gen`ichi jiban ekijoka potential no hyoka. 1. System kosei oyobi genchi yosatsu keisoku kekka

    Inazaki, T. [Public Works Research Institute, Tsukuba (Japan)


    For the purpose of evaluating liquefaction in situ, it was proposed that an S-wave vibrator designed to serve as a source in a reflection exploration method be utilized as a strong vibration generating source, and measurement was conducted in this connection. Equipment used in this test included an S-wave vibrator, static cone penetration machine, and various measuring cones. A multiplicity of measuring cones had been inserted beforehand into the target layers and comparison layers, and changes upon vibrator activation were measured. On a dry bed of the Tonegawa river, a 40m{sup 2} field was set up, and 41 cone penetration tests were conducted, with the cones positioned zigzag at 5m intervals. In this way, the ground structure was disclosed from the surface to the 10m-deep level. For the measurement, 3-component cones and seismic cones were placed at prescribed depths, and fluctuations and waveforms presented by pore water pressure at each level were determined with the vibration source changing its place. It was found that the changes in the pore water pressure exposed to vibration assume characteristic patterns corresponding to the conditions of vibration application. 5 figs., 1 tab.

  19. Fiscal 1999 achievement report. Venture seed pickup type international cooperative research project (Development of multi-beam semiconductor laser-aided preparation system for photogravure printing using water-based ink); 1999 nendo venture seeds hakkutsugata kokusai kyodo kenkyu jigyo seika hokokusho - venture seeds No.8. Suisei ink wo mochiita gurabia (oban) insatsuyo multi beam handotai laser seihan system no kaihatsu



    For the prevention of environmental contamination due to oil-based ink used in the photogravure printing process, efforts were exerted to develop a technique of laser-aided photogravure printing using a water-based ink. It was learned that the laser optical system technology of CR Corporation of Canada was practical and high in quality, and a delay occurred in the development of an evaporation type resin for use under this project. Then the initially planned design was abandoned for a type using a new optical system manufactured by CR Corporation. In the development of plate making materials, it was found that resin evaporation was incomplete in a 1-layer structure design. A 2-layer structure design was then employed instead, and the evaporation goal was achieved. Now that the optical system was changed, the resin was also replaced with a thermosensitive type, which enhanced work efficiency. The CR Corporation-manufactured laser optical system was installed on a mount, the processor system was controlled and adjusted, and a printing test was conducted using a water-based ink of German make. It was found that the product of the new system was higher in quality than that printed by the conventional mechanical perforation type printer using an oil-based ink. (NEDO)

  20. Improvement of the efficiency characteristics on the photovoltaic generation system based on a generation control circuit. Part 3. Research on architectural systematization of energy conversion devices; Dosaten seigyo kairo wo mochiita taiyo denchi hatsuden koritsu no kaizen. 3. Energy henkan no kenchiku system ka ni kansuru kenkyu

    Shimizu, T.; Ito, N.; Kimura, G.; Fukao, S.; Sunaga, N.; Tsunoda, M.; Muro, K. [Tokyo Metropolitan University, Tokyo (Japan)


    In introducing a photovoltaic power generation system to urban homes, the general practice is to install a large number of solar cell panels on the roof. However, as is often the case, a part of the solar cell panels is in the shadows (partial shadows) of neighboring homes, electric poles, cables and trees. Under the circumstances, studies were made on the numerous changes in the lowered generating capacity of individual solar cells by the partial shadows. Developed by the authors were the generation point control principle, in which the generation point was individually controlled on serially connected plural solar cell modules, and a practical circuit system based on that principle with the effects verified in a field test. In the test, the generated power of the system was 476W without partial shadows, and was 323W with partial shadows and without the operation of the generation point control circuit, increasing to 406W with partial shadows and with the operation of the circuit. As a result, compared with the case where no generation point control circuit was employed, the effectiveness of the proposed circuit was evident. 3 refs., 10 figs., 1 tab.

  1. Defect engineering of two-dimensional WO3 nanosheets for enhanced electrochromism and photoeletrochemical performance

    Zhou, Xiaofang; Zheng, Xiaoli; Yan, Bo; Xu, Tao; Xu, Qun


    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.

  2. AC conductivity and dielectric properties of bulk tungsten trioxide (WO{sub 3})

    El-Nahass, M.M. [Department of Physics, Faculty of Education, Ain Shams University, Roxy 11757, Cairo (Egypt); Ali, H.A.M., E-mail: [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)


    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.

  3. Investigation of multiferroic properties in MnWO{sub 4} by SHG-spectroscopy

    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)


    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.

  4. Recognizing Amino Acid Chirality with Surface-Imprinted Polymers Prepared in W/O Emulsions

    Min Jae Shin


    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.

  5. Effects of high pressure on the optical absorption spectrum of scintillating PbWO4 crystals

    Errandonea, D.; Martinez-Garcia, D.; Lacomba-Perales, R.; Ruiz-Fuertes, J.; Segura, A


    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...

  6. Systematical investigation on the luminescence enhancement of PbWO4 crystals by doping and annealing

    Huang, Yanlin


    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.

  7. A New Hydrogen Sensor Based on SNS Fiber Interferometer with Pd/WO3 Coating

    Jinxin Shao


    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.

  8. Graphene Q-switched Tm:KY(WO4)2 waveguide laser

    Kifle, E.; Mateos, X.; Loiko, P.; Yumashev, K.; Yasukevich, A.; Petrov, V.; Griebner, U.; Aguiló, M.; Díaz, F.


    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.

  9. Solvothermal synthesis, characterization and photocatalytic performance of Zn-rich ZnWO4 nanocrystals

    Wang, Yunjian; Liping, Li; Li, Guangshe


    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.

  10. Synthesis and characterization of WO{sub 3} nanostructures prepared by an aged-hydrothermal method

    Huirache-Acuna, R., E-mail: [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)


    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.

  11. Pulse-shape discrimination with PbWO$_4$ crystal scintillators

    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


    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.

  12. Pulse-shape discrimination with PbWO{sub 4} crystal scintillators

    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:; 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)


    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.

  13. Precipitation Synthesis, Characterization, Morphological Control, and Photocatalyst Application of ZnWO4 Nanoparticles

    Hosseinpour-Mashkani, S. Mostafa; Maddahfar, Mahnaz; Sobhani-Nasab, Ali


    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.

  14. Propane oxidation on Pt-WO3/g -AL2O3 catalytic systems

    Silva M.A.Pereira da


    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.

  15. Oxidative Desulfurization of Diesel Fuel with Hydrogen Peroxide Using Na2WO4 s Catalyst

    Sun Xin; Long Jun; Xu Benjing; Xie Chaogang


    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.

  16. Hydrothermal synthesis of TiO2/WO3 compositions and their photocatalytic activity

    Pyachin, Sergey A.; Karpovich, Natalia F.; Zaitsev, Alexey V.; Makarevich, Konstantin S.; Burkov, Alexander A.; Ustinov, Alexander Yu.


    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.

  17. Characterization of MnWO4 with flower-like clusters produced using spray pyrolysis

    Somchai THONGTEM; Surangkana WANNAPOP; Titipun THONGTEM


    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.

  18. The growth units and hydrothermal preparation of lead tungstate (PbWO4) crystallites

    元如林; 施尔畏; 李汶军; 郑燕青; 吴南春; 仲维卓


    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.

  19. Electronic Structures of PbWO4 Crystals Containing F-Type Colour Centres

    YI Zhi-Jun; LIU Ting-Yu; ZHANG Qi-Ren; SUN Yuan-Yuan


    @@ 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.

  20. The growth units and hydrothermal preparation of lead tungstate (PbWO4) crystallites


    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.

  1. Preparation of CuCrO2-WO3 and its photocatalytic performance for hydrogen production%CuCrO2-WO3的制备及光催化产氢性能

    王桂赟; 刘先平; 赵茜; 王延吉; 林瑞榕


    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

  2. Development of w/o microemulsion for transdermal delivery of iodide ions.

    Lou, Hao; Qiu, Ni; Crill, Catherine; Helms, Richard; Almoazen, Hassan


    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.

  3. Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter

    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


    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.

  4. Structural, microstructural and vibrational analyses of the monoclinic tungstate BiLuWO{sub 6}

    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: [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France)


    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.

  5. High efficiency, hybrid electrochromic device on polycarbonate substrates with neon sputtered WO3-x thin films


    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...

  6. Synthesis, Analysis, and Testing of BiOBr-Bi2WO6 Photocatalytic Heterojunction Semiconductors

    Xiangchao Meng; Zisheng Zhang


    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...

  7. Direct observation of photoinduced charge redistribution of WO3-TiO2 double layer nanocomposite films by photoassisted Kelvin force microscopy

    Wang, S. J.; Cheng, G.; Jiang, X. H.; Li, Y. C.; Huang, Y. B.; Du, Z. L.


    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.

  8. Fabrication and photocatalytic activity enhanced mechanism of direct Z-scheme g-C3N4/Ag2WO4 photocatalyst

    Zhu, Bicheng; Xia, Pengfei; Li, Yao; Ho, Wingkei; Yu, Jiaguo


    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.

  9. Room-temperature deposition of nanocrystalline PbWO 4 thin films by pulsed laser ablation

    Ryu, J. H.; Yoon, J.-W.; Shim, K. B.; Koshizaki, N.


    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.

  10. Spectroscopy of tetragonal Eu:NaGd(WO4)2 crystal

    Loiko, P. A.; Vilejshikova, E. V.; Mateos, X.; Serres, J. M.; Dashkevich, V. I.; Orlovich, V. A.; Yasukevich, A. S.; Kuleshov, N. V.; Yumashev, K. V.; Grigoriev, S. V.; Vatnik, S. M.; Bagaev, S. N.; Pavlyuk, A. A.


    We report on growth and detailed spectroscopic study of Eu3+-doped tetragonal sodium gadolinium double tungstate, Eu:NaGd(WO4)2, a new promising crystal for deep-red lasers. Large-volume crystal doped with 4.9 at.% Eu is grown by Czochralski method along the [001] crystallographic direction. Absorption of Eu3+ ions is studied at room temperature (RT) and at 6 K. For the absorption band related to the 7F1 → 5D1 transition suitable for pumping of Eu:NaGd(WO4)2, the maximum cross-section is σabs = 1.2 × 10-21 cm2 at 535.5 nm with the full width at half maximum (FWHM) of 3.1 nm (at RT, for E || a polarization). For the 5D0 → 7F4 transition, the maximum stimulated-emission cross-section is σSE = 1.6 × 10-21 cm2 at 698.3 nm (RT, E || c polarization). Lifetime of the 5D0 state is 490 ± 10 μs (at RT). Under UV excitation, Eu:NaGd(WO4)2 provides intense red emission with CIE coordinates (x = 0.671, y = 0.329).

  11. Photocatalytic degradation of MO by complex nanometer particles WO3/TiO2

    CUI Yumin


    Complex nanometer particles WO3/TiO2 were prepared using a sol-gel process and characterized using XRD spectra. The photocatalytic activity of TiO2 can be increased by doping W6+ with TiO2 because the doped W6+ that entered into the crystal lattices of TiO2 led to the formation of defects in the crystal lattices of TiO2 and thereby improved the photocatalytic activity of TiO2.When WO3 doped in TiO2 exceeded 3%, the excess W6+ did not enter into the crystal lattices of TiO2 but were uniformly dispersed in TiO2 or they covered the surface of TiO2, which reduced the effective illumination area of TiO2 and thereby lowered the photocatalytic activity of TiO2.The relationship among the composition of the catalyst,the amount of photocatalyst, the illumination time, and the decolorizing rate of methyl orange (MO) were discussed. The results show that the decolorizing rate of MO can reach 82.3% using WO3/TiO2 as the photocatalyst, with the composition tion time = 7 h.

  12. TiO2/WO3 photoactive bilayers in the UV-Vis light region

    Vasilaki, E.; Vernardou, D.; Kenanakis, G.; Vamvakaki, M.; Katsarakis, N.


    In this work, photoactive bilayered films consisting of anatase TiO2 and monoclinic WO3 were synthesized by a sol-gel route. Titanium isopropoxide and tungsten hexachloride were used as metal precursors and deposition was achieved by spin-coating on Corning glass substrates. The samples were characterized by X-ray diffraction, photoluminescence, UV-Vis, and Raman spectroscopy, as well as field emission scanning electron microscopy. The prepared immobilized catalysts were tested for their photocatalytic performance by the decolorization of methylene blue in aqueous matrices, under UV-Vis light irradiation. The annealing process influenced the crystallinity of the bilayered films, while the concentration of the tungsten precursor solution and the position of the tungsten trioxide layer further affected their photocatalytic performance. In particular, the photocatalytic performance of the bilayered films was optimized at a concentration of 0.1 M of the WO3 precursor solution, when deposited as an overlying layer on TiO2 by two annealing steps ( 76% methylene blue decolorization in 300 min of irradiation versus 59% in the case of a bare TiO2 film). In general, the coupled layer catalysts exhibited superior photoactivity compared to that of bare TiO2 films with WO3 acting as an electron trap, resulting, therefore, in a more efficient electron-hole separation and inhibiting their recombination.

  13. Visualization of X-ray Beam Using CdWO4 Crystal for Macromolecular Crystallography

    Kazimierz J. Gofron


    Full Text Available In synchrotron diffraction experiments, it is typically assumed that the X-ray beam at the sample position is uniform, stable and has dimensions that are controlled by the focus and slits settings. As might be expected, this process is much more complex. We present here an investigation of the properties of a synchrotron X-ray beam at the sample position. The X-ray beam is visualized with a single crystal scintillator that converts X-ray photons into visible light photons, which can be imaged using Structure Biology Center (SBC on-axis and off-axis microscope optics. The X-ray penetration is dependent on the composition of the scintillator (especially the effective Z, and X-ray energy. Several scintillators have been used to visualize X-ray beams. Here we compare CdWO4, PbWO4, Bi4Ge3O12, Y3Al5O12:Ce (YAG:Ce, and Gd2O2S:Tb (phosphor. We determined that scintillator crystals made of CdWO4 and similar high-Z materials are best suited for the energy range (7–20 keV and are most suitable for beam visualization for macromolecular crystallography applications. These scintillators show excellent absorption, optical, and mechanical properties.

  14. Visualization of X-ray Beam Using CdWO4 Crystal for Macromolecular Crystallography

    Kazimierz J. Gofron


    Full Text Available In synchrotron diffraction experiments, it is typically assumed that the X-ray beam at the sample position is uniform, stable and has dimensions that are controlled by the focus and slits settings. As might be expected, this process is much more complex. We present here an investigation of the properties of a synchrotron X-ray beam at the sample position. The X-ray beam is visualized with a single crystal scintillator that converts X-ray photons into visible light photons, which can be imaged using Structure Biology Center (SBC on-axis and off-axis microscope optics. The X-ray penetration is dependent on the composition of the scintillator (especially the effective Z, and X-ray energy. Several scintillators have been used to visualize X-ray beams. Here we compare CdWO4, PbWO4, Bi4Ge3O12, Y3Al5O12:Ce (YAG:Ce, and Gd2O2S:Tb (phosphor. We determined that scintillator crystals made of CdWO4 and similar high-Z materials are best suited for the energy range (7–20 keV and are most suitable for beam visualization for macromolecular crystallography applications. These scintillators show excellent absorption, optical, and mechanical properties.

  15. WO3/Pt nanoparticles promote light-induced lipid peroxidation and lysosomal instability within tumor cells

    Clark, Andrea J.; Petty, Howard R.


    Although metal-metal oxide nanoparticles have attracted considerable interest as catalysts, they have attracted little interest in nanomedicine. This is likely due to the fact that metal oxide semiconductors generally require biologically harmful ultraviolet excitation. In contrast, this study focuses upon WO3/Pt nanoparticles, which can be excited by visible light. To optimize the nanoparticles’ catalytic performance, platinization was performed at alkaline pH. These nanoparticles destroyed organic dyes, consumed dissolved oxygen and produced hydroxyl radicals. 4T1 breast cancer cells internalized WO3/Pt nanoparticles within the membrane-bound endo-lysosomal compartment as shown by electron and fluorescence microscopy. During visible light exposure, but not in darkness, WO3/Pt nanoparticles manufacture reactive oxygen species, promote lipid peroxidation, and trigger lysosomal membrane disruption. As cells of the immune system degrade organic molecules, produce reactive oxygen species, and activate the lipid peroxidation pathway within target cells, these nanoparticles mimic the chemical attributes of immune effector cells. These biomimetic nanoparticles should become useful in managing certain cancers, especially ocular cancer.

  16. Hydrothermal Synthesis, Characterization, and Visible Light-Driven Photocatalytic Properties of Bi2WO6 Nanoplates

    Anukorn Phuruangrat


    Full Text Available In this research, the effects on reaction temperature and length of time on Bi2WO6 nanoplates by hydrothermal synthesis on morphologies and photocatalytic properties were studied. The products obtained at different reaction temperature and reaction time were characterized by XRD, Raman, FTIR, SEM, and TEM techniques. The photocatalytic properties of the samples were measured by decomposing the rhodamine-B organic dye. XRD pattern was specified as pure orthorhombic well-crystallized Bi2WO6 phase for the 180°C and 20 h synthesis. Its FTIR spectrum shows main absorption bands at 400–1000 cm−1, assigned to Bi–O stretching, W–O stretching, and W–O–W bridging stretching modes. SEM and TEM analyses show that the product was composed of nanoplates. Photocatalytic activity of Bi2WO6 nanoplates shows the 98.24% degradation of rhodamine-B under the Xe light irradiation within 100 min.

  17. Photoelectrochemical behavior of nanostructured WO3 thin-film electrodes: The oxidation of formic acid.

    Monllor-Satoca, Damián; Borja, Luis; Rodes, Antonio; Gómez, Roberto; Salvador, Pedro


    Nanostructured tungsten trioxide thin-film electrodes are prepared on conducting glass substrates by either potentiostatic electrodeposition from aqueous solutions of peroxotungstic acid or direct deposition of WO3 slurries. Once treated thermally in air at 450 degrees C, the electrodes are found to be composed of monoclinic WO3 grains with a particle size around 30-40 nm. The photoelectrochemical behavior of these electrodes in 1 M HClO4 apparently reveals a low degree of electron-hole recombination. Upon addition of formic acid, the electrode showed the current multiplication phenomenon together with a shift of the photocurrent onset potential toward less positive values. Photoelectrochemical experiments devised on the basis of a kinetic model reported recently [I. Mora-Seró, T. Lana-Villarreal, J. Bisquert, A. Pitarch, R. Gómez, P. Salvador, J. Phys. Chem. B 2005, 109, 3371] showed that an interfacial mechanism of inelastic, direct hole transfer takes place in the photooxidation of formic acid. This behavior is attributed to the tendency of formic acid molecules to be specifically adsorbed on the WO3 nanoparticles, as evidenced by attenuated total reflection infrared spectroscopy.

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

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


    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.

  19. Carbon materials as additives to WO3 for an enhanced conversion of simulated solar light

    Rocío Jiménez Carmona


    Full Text Available We have explored the impact of the incorporation of nanoporous carbons as additives to tungsten oxide on the photocatalytic degradation of two recalcitrant pollutants: rhodamine B and phenol, under simulated solar light. For this purpose, WO3/carbon mixtures were prepared using three carbon materials with different properties (in terms of porosity, structural order and surface chemistry. Despite the low carbon content used (2 wt. %, a significant increase in the photocatalytic performance of the semiconductor was observed for all the catalysts. Moreover, the influence of the carbon additive on the performance of the photocatalysts was found to be very different for the two pollutants. Carbon additives of hydrophobic nature increased the photodegradation yield of phenol compared to bare WO3, likely due to the higher affinity and stronger interactions of phenol molecules towards basic nanoporous carbons. Oppositely, the use of acidic carbon additives led to higher rhodamine B conversions due to increased acidity of the WO3/carbon mixtures and the stronger affinity of the pollutant for acidic catalyst’s surfaces. As a result, the photooxidation of rhodamine B is favored by means of a coupled (photosensitized and photocatalytic degradation mechanism. All these results highlight the importance of favoring the interactions of the pollutant with the catalyst’s surface through a detailed design of the features of the photocatalyst.

  20. BiVO(4)/CuWO(4) heterojunction photoanodes for efficient solar driven water oxidation.

    Pilli, Satyananda Kishore; Deutsch, Todd G; Furtak, Thomas E; Brown, Logan D; Turner, John A; Herring, Andrew M


    BiVO(4)/CuWO(4) heterojunction electrodes were prepared using spray deposition of a highly porous bismuth vanadate film onto the surface of an electrodeposited three dimensional network connected copper tungstate. Bilayer BiVO(4)/CuWO(4)/fluorine doped tin oxide glass (FTO) electrodes demonstrated higher photocurrent magnitudes than either with BiVO(4)/FTO or CuWO(4)/FTO electrodes in 1.0 M Na(2)SO(4) electrolyte buffered at pH 7. The photocurrent is enhanced by the formation of the heterojunction that aids charge carrier collection brought about by the band edge offsets. When the pH 7 buffered electrolytes contained 1.0 M bicarbonate is employed instead of 1.0 M sulfate, the charge transfer resistance was decreased. This led to nearly 1.8 times the photocurrent density at 1.0 V vs. Ag/AgCl. The photocurrent was stable over 24 hours in bicarbonate electrolyte.