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Sample records for teitankadotan wo mochiita

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    1997-02-01

    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.

  2. 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

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

    1991-12-20

    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.

  3. Biodegradable polymeric foam with food waste; Shokumotsu zansa wo mochiita seibunkai kobunshi hahhotai

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, Kenji; Matsuyama, Kiyoshi; Yamauchi, Satoru; Takarabe, Shin' ichi

    1999-09-01

    A huge amount of food waste such as tea and beer dregs becomes a serious problem because of the lack of industrial waste space in Japan. On the other hand, the new polymeric foam is expected to be developed since the dangerous pollution of endorphin disrupters from industrial polymer foam is pointed out. In this work, we try to develop the biodegradable polymeric foam using the tea and beer dregs as secondary resources. And we examined the degradability of biodegradable polymer in the hydrothermal water for fundamental knowledge of polymeric foam production. We used an extruder equipped with a high pressure device to make the polymeric foam. And we examined the effect of the component ratio on the foam properties, foaming rate, strength, shrinkage rate, water-resistant. As a result, it was found that the amount of polymer is effective of quality of form and the biodegradability can be controlled by the amount of water and temperature. (author)

  4. Field tests of electric survey using capacitive electrodes; Kyapashita denkyoku wo mochiita denki tansarei

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    Miyazaki, I.; Iseki, S.; Kobayashi, T. [OYO Corp., Tokyo (Japan)

    1997-10-22

    This paper describes field test results of electric survey using capacitive electrodes. When two metal plates are approached without contacting with the ground and voltage is applied between the plates, current flows in the ground. The metal plates and the ground work as a capacitor. Charges are stored between them. These metal plates having insulation with the ground are called capacitive electrodes. When ac voltage is applied between a pair of capacitors, current flows continuously in the ground without saturating the capacitors. Resistivity of the ground can be determined by measuring the level of current flowing in the ground and the level of potential. As a result of the field tests, it was found that the present method is superior to the conventional method in around ten times. However, to obtain high quality data, water spraying, reduced towing speed at the low resistivity ground such as clay and soil, and grass mowing are required. 3 refs., 5 figs., 1 tab.

  5. Measurement of sea ice thickness using electromagnetic sounding; Denji tansaho wo mochiita kaihyoatsu no keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Kawauchi, K.; Suzuki, I.; Goto, N. [Muroran Institute of Technology, Hokkaido (Japan); Hoshiyama, K.

    1997-10-22

    Thickness of sea ice is measured by an electromagnetic method making use of the peculiarities of sea ice. Sea ice floats on the seawater (saline water), and the result is two horizontal layers greatly different from each other in conductivity, with seawater being highly conductive and ice being non-conductive. A study is conducted on Lake Kumatori, a saline lake in Abashiri City, in which effort a board of naturally frozen sea ice and a board of sea ice allowed to form on the sea surface at a spot from which ice has been removed are examined. A portable electromagnetic probe EM38 of GEONICS Company is employed to perform measurement in a horizontal dipole mode. To determine the relationship between the obtained conductivity measurements and sea ice thickness, holes are bored in the sea ice boards for the measurement of their thickness for the formulation of an experimental regression equation. Measurements along the traverse line 1 and traverse line 3 are converted into sea ice thickness by use of the experimental regression equation, and the result is that ice thickness is the greatest near the quay growing thinner away from the shore. The study shows that sea ice thickness may be measured accurately by electromagnetic probing. 3 refs., 10 figs.

  6. Soil surveying using electromagnetic methods; Denji tansaho wo mochiita jiban chosa

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, I.; Kawauchi, K.; Goto, N. [Muroran Institute of Technology, Hokkaido (Japan); Takahashi, N.; Yamada, T. [Zukohsya Co. Ltd., Hokkaido (Japan)

    1997-10-22

    Electromagnetic surveying method is applied in Muroran Institute of Technology`s site for power transmission steel towers for the locating of structures buried in the ground and for the study of obstruction to the application of the method. The devices employed are the EM31 and EM38 which are portable conductivity measuring instruments manufactured by GEONICS Company. With the probeable depth in the horizontal dipole mode being approximately half that in the vertical dipole mode, depths of 0.5m, 1m, 3m, and 6m may be explored using the two instruments. In the measurement test, the devices are used to determine a reinforced concrete-made multi-purpose duct that accommodates water pipes, sewers, various electric wires, and heating pipes and is buried at a depth of 2-3m in the ground. In the measurement for a 3m-deep level, a spot high in conductivity due to the reinforced concrete is detected, and the result roughly corresponds to the lay of the duct. In the measurement for a 6m-deep level, no high-conductivity spot is found, meaning there is no such structure at this depth. Although there are some other high conductivity values recorded, they are attributed to manhole covers or steel tower bases on the ground surface. 3 refs., 8 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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. Achievements of operator training using ABWR simulator; ABWR shiyumireta wo mochiita unten kunren no jisseki

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yasuhiro; Kondo, Shin' ichi; Watabe, Kazuyuki; Kobayashi, Akira

    1999-05-15

    BWR Operator Training Center Corporation (BTC) has been offering operator training for BWR utilities in Japan since 1974. In 1994, we started ABWR operator training using an ABWR full scope simulator. Numerous improvements that influence the methods of operator training, have been incorporated to the ABWR main control panel. This report describes the achievements of ABWR operator training in consideration of the control panel improvements. (author)

  11. Measurements on thermal expansion with strain gauge; yugami geji wo mochiita gokuteion netsubochoritsu no keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, T.; Sato, A. [National Research Inst. for Metals, Tokyo (Japan); Arai, O.; Okuda, Y. [Tokyo Inst. of Tech., Tokyo (Japan)

    1999-11-10

    As the part of very low temperature thermophysical property measurement technique standardization by the intelligent basis promotion system, very low temperature coefficient of thermal expansion measurement method using the strain gauge was examined. Here, DyVO4 that that it has the unique temperature dependency as a sample for the test at 20K or less was expected was taken up. The strain gauge, which constituted bridge circuit using strain sensor of 4 used by fatigue test of very low temperature, was produced, and the measurement of coefficient of thermal expansion was tried. (NEDO)

  12. Capacitive pressure transducer using flexible films. Junan film wo mochiita seiden yoryoshiki atsukaku transducer

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Y.; Tsuchida, N.; Imai, K. (Toyota Technological Institute, Aichi (Japan)); Fujita, K. (Nitto Denko Corp., Osaka (Japan)): Tsuboi, O. (Fujitsu Corp., Tokyo (Japan))

    1992-12-20

    This paper describes the design, manufacture, and evaluation of a capacitive pressure transducer made of polyimide films. The structure of a pressure transducer cell was first determined, and then, the deflection-stress and capacitance-load characteristics of the surface film were analyzed using finite element methods. For the practical stage of manufacture, a polyimide film was emboss processed and electrodes were deposited on the film to construct a pressure transducer cell to which a Schmidt-trigger detecting circuit was connected. As a consequence of the examination of operational characteristics of the cell, it was found that the actual relation between the deflection and load approximately agreed with the linear analyses, and that the capacitance depended with little hysteresis on the gap regardless of the native visco-elasticity of the film. Furthermore, small stick-slip vibration of a contact rubber surface was detected by the transducer to verify its high sensitivity. 17 refs., 18 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

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

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

    1996-10-01

    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.

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

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

    1996-10-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-20

    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.

  17. Toxicity testing using conchospores and their germlings of porphyra yezoensis; Susabinori no kara hoshi to hatsugatai wo mochiita dokusei shikenho

    Energy Technology Data Exchange (ETDEWEB)

    Takami, T. [Miyazaki Univ., Miyazaki (Japan). Graduate School; Maruyama, T.; Suzuki, Y. [Miyazaki Univ., Miyazaki (Japan). Faculty of Engineering; Miura, A. [Aomori Univ., Aomori (Japan). Faculty of Engineering

    1997-05-22

    In the development of a toxicity test for specimen of conchospores released from conchocelis, it is necessary to quantitate the influence on the step of adhering conchospores to substrata and the growing step of germlings after adhering. In this study, in order to develop a toxicity test using the germling step of conchocelis, the released number and a period from conchocelis, the adhering substrata and the adhering methods of conchospores were investigated, and the results were obtained as follows: As for conchospores, about 80% of the released number per day were released from mature conchocelis within 3 hours after a light was switched on. Release of conchospores took place after 4 days from when conchocelis were cultivated under the conditions of short day and low temperature, and lasted until at least 30 days. The natural sedimentation using a glass plate was the most adequate for the adhesion of conchospores. The high reappearance for the adhesion rate of conchospores from the glass plate and the survival rate of germlings after 7 days was shown even if the released date and the released number of conchospores were different. 27 refs., 8 figs., 1 tab.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-27

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-27

    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.

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

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

    1996-10-28

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-28

    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.

  2. Equivalent circuits of vibratory gyroscopes using a flexurally-vibrating resonator. Yokoshindo onhen wo mochiita shindo gyrosocpe no toka kairo

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, S.; Kondo, M.; Kudo, S. (Ishinomaki Senshu University, Miyagi (Japan))

    1991-09-20

    This paper describes an equivalent circuit condidered for analyzing the coordinate transformation between two orthogonal natural vibrating mode pairs of a flexurally-vibrating double-resonant vibrator having a square- or regular triangular cross-section. A comprehensive electromechanical equivalent circuit was presented in order to clarify the behaviour of a difference detection type resonator-vibrating gyroscope using a new drive system where the resonator is piezoelectrically driven and detected. As a result, the relation was clarified between the coordinate transformation between the orthogonal natural vibrating mode pairs of a resonator having a square cross-section and the equivalent circuit of the resonator. Further a resonator vibrating gyroscope of a square cross-section was constructed based on 'Murata system', and its comprehensive electric equivalent circuit was obtained and partially verified by experiment. Also for resonators of a regular triangular cross-section, a similar equivalent circuit in consideration with their coordinate transformation was derived and a comprehensive electromechanical equivalent circuit was presented for a piezoelectric resonator gyroscope. As a consequence, the relationship between coordinate transformation and equivalent circuit is clarified; the characteristics simulation and the design of a vibratory gyroscope was enabled by using the above comprehensive electromechanical equivalent circuit. 7 refs., 15 figs.

  3. Application of the seismic survey ahead of tunnel face; Danseiha wo mochiita kiriha zenpo tansa no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, S.; Nakajima, N. [JDC Corporation, Tokyo (Japan)

    1997-10-22

    Measurements have been made in a water channel tunnel having a small diameter and shallow earth covering, by using a tunnel seismic prediction (TSP) system to predict the nature of soil up to about 150 meters ahead of a face, which uses reflection method elastic waves. The water channel tunnel has a diameter of 2.8 m, and extends over a total distance of 706 m. The nature of soil at the face is composed of rocks, in which dark gray and hard striped phthanites are distributed and joint interval is about 20 cm. The measurements were performed on 24 vibration holes with hole interval of about 1.5 m using an explosive of 50 grams per hole. Diffraction stack processing method was used to execute the analysis. As a result of the discussions, a point changing from hard to soft soil was predicted at a point 18 m ahead of the face, and a point changing from soft to hard soil at a point 70 m ahead of the face. The changing point for the soil nature as observed by drilling showed a discrepancy of 10 m at the point changing from hard to soft soil as compared with the prediction derived by using the TSP exploration. No discrepancy was recognized in the point changing from soft to hard soil. The discrepancy is thought to have been caused from the geological change in the explored area being moderate and the lithofacies being free from change. 8 figs., 2 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

    1997-05-27

    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.

  6. Corrosion test of coated steel sheets using hem model. Hem model wo mochiita kakushu hyomen shori koban no fushoku shiken

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, S.; Sakai, H.; Iwai, M.; Arimura, M. (Kobe Steel, Ltd., Kobe (Japan))

    1993-10-01

    The outdoor exposure corrosion test results of the hem model attached inside an automotive door for two years (May, 1986 - May, 1988) were reported as well as the cyclic corrosion test results of the hem model including cyclic salt spray, drying and wetting repeated 200 times. The hem models were made of some kinds of surface treated steel sheets such as electrogalvanizing one, and coated by dipping phosphating and cation electrodeposition like practical automotive coating. As a result, the corrosion depth of the hem models showed the largest value around the top of lapped panel portions, and under-film corrosion conditions of the hem models and temperature/humidity measurement results suggested a cyclic dry/wet condition inside a door. In the exposure test, the corrosion depth decreased with an increase in Zn coating weight indicating the clear effect of a coating weight on a corrosion depth resistance, however, in the cyclic corrosion test, no clear protective effect of Zn coating was obtained. 5 refs., 10 figs.

  7. Resin composite for sealing and its use in a solar cell. Fushiyo jushi soseibutsu oyobi sore wo mochiita taiyo denchi

    Energy Technology Data Exchange (ETDEWEB)

    Toma, H.; Mimura, T.; Takehara, N.

    1994-01-28

    This invention presents resin composites for sealing of a solar cell composed of a hardening resin and a thermoplastic resin which has a number average molecular weight larger than that of the hardening resin and is soluble in the hardening resin, and the invention affords a solar cell to endure a long-term stable operation and to give a good performance. The hardening resin includes unsaturated polyester resin, phenolic resin, alkyd resin, unsaturated acrylic resin, epoxy resin, polyurethane resin, melamine resin, diallyl phthalate resin, their oligomers and their modifications. The thermoplastic resin includes saturated polyester resin, phenolic resin, acrylic resin, styrene resin, epoxy resin, polyurethane resin, polyvinyl acetate resin, polyvinyl chloride resin, polyvinyl alcohol resin, polyacetal resin, their modifications and their copolymer resin. 2 figs., 3 tabs.

  8. Measurements on thermal expansion with strain gauge 2; Yugami geji wo mochiita gokuteion netsu bochoritsu no keisoku 2

    Energy Technology Data Exchange (ETDEWEB)

    Arai, O.; Numazawa, T.; Sato, A. [National Research Inst. of Metals, Tokyo (Japan); Okuda, Y. [Tokyo Inst. of Tech., Tokyo (Japan)

    2000-05-29

    As the part of very low temperature thermophysical property measurement technique standardization by the intelligent basis promotion system, it examined very low temperature coefficient of linear expansion measurement method using the strain gauge. It produced the clip, which constituted the bridge circuit using strain sensor of 4 used by fatigue test of very low temperature, and it tried the measurement of convenient and quick coefficient of linear expansion from low temperature over high temperature. (NEDO)

  9. Basic properties of high strength concrete using admixture; Bifunmatsu konwazai wo mochiita chokokyodo concrete no kihon seijo

    Energy Technology Data Exchange (ETDEWEB)

    Kono, M.; Okihashi, T.; Uenishi, T. [Okumura Corp., Osaka (Japan)

    1997-07-31

    For high strength concrete of Fc=100N/mm{sup 2} class, the effect of fine powder admixtures on reduction of concrete viscosity and improvement of strengthening property was studied. The experiment was carried out under different kinds and displacement rates of admixtures, and different water/binder ratios using specific metakaolin and silica fume as admixtures. The test items are as follows: measurement of pore size profiles, adiabatic temperature rise test, and strength test of temperature follow-up cured specimens simulating structural members. As a result, the viscosity of fresh concrete largely decreased by adding silica fume, while increased by adding specific metakaolin. The compressive strength of concrete mixed with silica fume was equal to or higher than that of non-mixture concrete. On the contrary, concrete mixed with specific metakaolin was remarkably strong in the early stage, however, growth of the strength decreased with an increase in age, and the strength was lower than that of non-mixture concrete after 91 days. 3 refs., 12 figs., 6 tabs.

  10. Development of syndiotactic PP technology using metallocene catalyst. Metallocene shokubai wo mochiita syndiotactic PP no gijutsu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Uchikawa, N. (Mitsui Toatsu Chemicals, Inc., Tokyo (Japan))

    1993-09-01

    This paper introduces a metallocene catalyst and syndiotactic PP synthesized therefrom. The metallocene catalyst discovered in 1980 is a combination of metallocene compound of the IV-family transition metal with methyl aluminoxane (MAO) as a promoter. The metallocene catalyst has its active species homogeneous and soluble to solvents, hence it is called a homogeneous-system polymerized catalyst. Further, its active species concentration is said to account for 65% or higher of the transition metal at normal temperatures, and has high polymerization activity and superior random copolymerization performance. A syndiotactic PP having high stereoregularity and macromolecules sufficient in amount as molding resin was synthesized in 1988 by using a combination of the metallocene catalyst with MAO. It has properties of crystallinity from 30% to 40%, a melting point in a range from 140[degree]C to 150[degree]C, and a density of 0.88. It has high normal-temperature impact strength, low bending elastic modulus, and high transparency, and is expected to develop into foodstuff and medical material packaging materials. 4 figs., 3 tabs.

  11. New biological deodrization device using dried activated sludge. Kanso odei wo mochiita shinki seibutsu dasshu sochi no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Hatakeyama, S.; Nagayasu, K.; Suwa, T.; Hayashitani, M.; Ito, H.; Habata, K.; Kitakaze, T. (Kawasaki Heavy Industries, Ltd., Tokyo (Japan))

    1993-10-20

    The new biological deodorization device was developed using dried activated sludge as deodorant. Activated sludge obtained from a waste water treatment plant was dried at room temperature to protect from extinction of microorganisms in it before its charge into the device, and washed by water only as required. Offensive odor substances were oxidation-decomposed by microorganism after their adsorption into sludge surfaces, while microorganisms survived for a long time while getting such substances as nutritive sources. As basic deodorization characteristics were studied with the experimental device and artificial odor gases, more than 99% of 200 and 2,000 ppm H2S were removed at space velocities of 400/h and 33/h, respectively, together with nine typical offensive odor substances. As the result of demonstration tests with the small test device installed in a public waste water treatment plant, a high deodorizing efficiency was retained for 10 months or more, and its running cost was as low as 75% of that of current systems because of only one necessary washing every month. 3 refs., 14 figs., 12 tabs.

  12. Measurement of simple shear strain with a uniaxial speckle strain meter; Laser speckle yugamikei wo mochiita sendan yugami no keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Muto, H.; Sakai, M. [Toyohashi University of Technology, Aichi (Japan)

    1998-10-01

    Elastic and viscoelastic shear strains induced in test specimens with double-shear geometry are measured by extending the conventional uniaxial speckle extensometry. The test results for soda-lime glass give excellent agreements with the shear modulus G at room temperature and the shear viscosity {eta} reported in the literature at temperatures from 530 to 555degC. The G and {eta} values are also in agreement with those measured by a strain-gage foil and by an electro-optical extensometer, respectively. This agreement confirms that the proposed technique and analysis for the measurement of shear strain with a uniaxial laser speckle strain meter are not only applicable for characterizing the mechanical properties of brittle materials in a small scale deformation, but also provide a powerful tool for studying the high-temperature deformation and flow of engineering materials in a large scale deformation. The issue of affine transformation of polycrystalline materials with local heterogeneity and anisotropy is also discussed by comparing the test results of speckle and electro-optical extensometries. 11 refs., 6 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    A report is given about the application of a synchronizing system using clock signals from GPS satellites to a remote reference method which is a technique to reject noise from the MT method. This system uses the C/A code out of the L1 band waves from NAVSTAR/GPS satellites. The new system was operated in MT method-using investigations conducted at China Peninsula, Aichi Prefecture, and Izu Peninsula, Shizuoka Prefecture, with the reference points placed several 100km away in Iwate Prefecture on both occasions. It was found as the result that it is basically possible to catch signals from the GPS at any place, that the signals are accurate enough to be applied to time synchronization for the MT method, and that the signals assure a far remote reference method with a separation of several 100km between the sites involved. The referencing process at high frequencies whose feasibility had been doubted proved a success when highly correlated signals were exchanged between two stations over a distance of several 100km. 5 refs., 9 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-16

    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)

  19. Prediction of powerplant vibration using FRF data of FE model; Dentatsu kansu wo mochiita power plant shindo yosoku

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, T.; Tsukahara, M.; Sakaguchi, M.; Takahashi, Y. [Honda R and D Co. Ltd., Tokyo (Japan)

    1997-10-01

    For the purpose of shortening the development period, the estimation of powerplant vibration has become more important in the early design stage, and eigenvalue analysis by FEM is commonly used to solve this problem. Eigenvalue Analysis cannot directly predict vibration levels under running conditions that affect the durability of each component and the vibration of a car body. This paper presents a new approach using FRF data from FE models for accurate prediction of engine vibration under running conditions. By applying this approach to an in-line four cylinder engine, the predicted vibration is reasonably comparable with experimental results. 3 refs., 8 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-05

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    1996-10-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-25

    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.

  4. Basic consideration on identification of objects using chirped ultrasonic wave; Chirp choonpa wo mochiita keijo hanbetsu no kisoteki kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Jitsumori, A. [Mitsubishi Electric Corp., Tokyo (Japan)] Ando, S. [Tokyo Univ. (Japan)

    1998-11-30

    Regarding identification of geometrical features of objects using echoes of ultrasonic pulses, there are generally two ways. One is the way that a beam of ultrasonic waves having sharp directivity scan on a object, and the other is the way that ultrasonic waves, irradiating a object so as to cover the whole of it, capture the features of all the object at a time. In this paper, the theoretical basis about the latter were investigated. A mathematical model with which lumpiness of a object can be dealed as the sum of echoes from relatively small number of certain particular points (stationary points) was derived. The stationary points meaning local maximal points, saddle points, etc., it was investigated what is the optimum waveform that can separate and identify echoes from other portions. It being difficult to supply high energy in short time, if temporal width of a pulse is made larger, resolution of echoes come to fall. As a measure for solution, contraction of pulse width was attempted using chirped ultrasonic wave (modulated carrier frequency). The pulse of AM (amplitude modification) or LFM (linear frequency modulation) being selected, experimental results agreed fairly well the simulations. 10 refs., 13 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-25

    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.

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

    Directory of Open Access Journals (Sweden)

    Danping Wang

    2016-05-01

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

  7. Phase diagrams of KY(WO4)2-KEr(WO4)2, KGd(WO4)2-KEr(WO4)2 systems and single crystal growth for some tungstates

    International Nuclear Information System (INIS)

    Yudanova, L.I.; Pavlyuk, A.A.; Potapova, O.G.

    1992-01-01

    Phase diagrams of the KY(WO 4 ) 2 -KEr(WO 4 ) 2 , KGd(WO 4 ) 2 -KEr(WO 4 ) 2 systems were studied by differential thermal and X-ray diffraction analyses. Continuous variety of solid solutions are in the KY(WO 4 ) 2 -KEr(WO 4 ) 2 system. They occurred just as in the area of alphaso beta-modifications. Limited areas of the solid solutions based on components were in the KGd(WO 4 ) 2 -KEr(WO 4 ) 2 system. Monocrystals of potassium-yttrium and potassium-gadolinium tungstates activated by erbium were grown using modified low-gradient Czochralski method

  8. Cu3Sm(WO4)3-Sm2(WO4)3 system

    International Nuclear Information System (INIS)

    Arzumanyan, G.A.

    1982-01-01

    Vast regions (up to 25 mol%) of the existence of limited solid solutions with Dalton compositions Cu 3 Sm(WO 4 ) 3 , Cu 13 Sm 7 x(WO 4 ) 17 , Cu 9 Sm 11 (WO 4 ) 21 and Cu 3 Sm 17 (WO 4 ) 27 possessing the structures related to scheelite distorted monoclinic structure of Eu 2 (WO 4 ) 3 A-phase were revealed in the Cu 3 Sm(WO 4 ) 3 -Sm 2 (WO 4 ) 3 system at 500-1100 deg C temperatures and oxigen partial pressure of 0.9-1.3 Pa (total pressure of the noble gas - 102.1+-0.6 kPa)

  9. Geoelectric study in attempt to detect of deformation around slice gate in the embankment; Hiteiko eizoho wo mochiita himon shuhen no yurumi ryoiki no suitei

    Energy Technology Data Exchange (ETDEWEB)

    Natori, T.; Nakayama, Y. [Hokkaido Sapporo Public Works Office, Sapporo (Japan); Hashimoto, Y.; Matsuo, J. [OYO Corp., Tokyo (Japan)

    1997-10-22

    For the river structures, such as slice gates and slice pipes, constructed on the weak ground, structures often come out due to forced settlement of embankment, which results in the formation of cavity and loose ground. These deformations can cause disasters due to leakage by water channel and fracture of bank. It is significant to detect and grasp these situations in early stage. In this study, resistivity imaging was conducted around slice gate in several times, to estimate the loose region based on the difference in the obtained resistivity data. Resistivity was measured in two times with a certain interval using the same line. The loose region around the slice gate was estimated from the change of saturation condition and the saturation line by considering the difference. Even in the case when judgment was hard by a single measurement, it was possible to estimate the loose region based on the difference from multiple measurements. 3 refs., 6 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    1996-10-28

    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.

  11. 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

    Energy Technology Data Exchange (ETDEWEB)

    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

    1996-10-28

    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.

  12. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-28

    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.

  13. Model support system using an industrial robot in low-speed wind tunnel; Sangyoyo robot wo mochiita fudo mokei shiji system

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, T.; Iwasaki, A.; Fujieda, H.; Shigemi, M. [National Aerospace Laboratory, Tokyo (Japan); Nakayasu, H.; Sagisaka, M. [National Space Development Agency of Japan, Tokyo (Japan)

    1994-06-01

    A model support system that can set the attitude with an attack angle, sideslip angle, and rotation angle as required by using the mechanism and function of an industrial robot and that can be rapidly moved to the specified position was developed. This system consists of a host computer, robot controller, and robot. A sting for wind tunnel model support and a six-component balance are installed at the tip of a robot arm. The robot has fix freedom levels and can control the attitude of the wind tunnel model. A model with weight capacity of 1470N and precision of {plus_minus}0.5 mm was selected. An A/D input block and external communication function were installed in the robot controller, in consideration of the dynamic floating effect that the machine continuously approaches a ground plate in the wind tunnel test of an experimental machine. The function test of a robot installed in the wind tunnel, the wind tunnel test using a robot, the comparison of aerodynamic data based on the difference of a model support system were investigated. The result showed that this system is very effective.

  14. 3D-image theater system using TLP770J LCD data projector; Ekisho data projector wo mochiita rittai eizo theater system

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-02-01

    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)

  15. Imaging of in-tunnel horizontal seismic profile using three-component accelerometers; Sanseibun kaoskudokei wo mochiita tunnel HSP no imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, S. [Nippon Geophysical Prospecting Co. Ltd., Tokyo (Japan); Isahai, H. [Kumagai Gumi Co. Ltd., Tokyo (Japan); Inazaki, T.; Kurahashi, T. [Public Works Research Institute, Tsukuba (Japan); Hagiwara, I. [Suncoh Consultant Co. Ltd., Tokyo (Japan)

    1997-10-22

    Analysis was made on data of measurements using three-component accelerometers for horizontal seismic profile (HSP) exploration as a method to investigate tunnel front, under a limited condition of work to be done inside a tunnel shaft. The analysis was intended to discuss feasibility of determining the reflection face. In the experiment, courses of traverse for the exploration were set on side walls, and vibration receiving and transmitting points were arranged. The courses of traverse had 22 in-tunnel seismographs installed at an interval of 1.5 m. The HSP processing has used three-component measurement records derived from three vibration transmitting points. After giving a pre-treatment, only the outward wave and inward wave components were extracted by applying a velocity filter as a method to separate the wave motion fields. A migration treatment was given on the inward wave component by using the GRT method to have derived position, direction and inclination of the obliquely crossed reflection face. As a result of having performed a comparison with the result of tunnel wall observation, distribution of the direction and inclination of the reflection face derived from the reflection intensity was found consistent with the distribution of direction and inclination of fissures and bedding planes obtained from the tunnel wall observation. Thus, a unique decision was concluded possible. 5 refs., 8 figs., 1 tab.

  16. Relative amplitude preservation processing utilizing surface consistent amplitude correction. Part 4; Surface consistent amplitude correction wo mochiita sotai shinpuku hozon shori. 4

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-22

    Discussions were given on seismic exploration from the ground surface using the reflection method, for surface consistent amplitude correction from among effects imposed from the ground surface and a surface layer. Amplitude distribution on the reflection wave zone is complex. Therefore, items to be considered in making an analysis are multiple, such as estimation of spherical surface divergence effect and exponential attenuation effect, not only amplitude change through the surface layer. If all of these items are taken into consideration, burden of the work becomes excessive. As a method to solve this problem, utilization of amplitude in initial movement of a diffraction wave may be conceived. Distribution of the amplitude in initial movement of the diffraction wave shows a value relatively close to distribution of the vibration transmitting and receiving points. The reason for this is thought because characteristics of the vibration transmitting and receiving points related with waveline paths in the vicinity of the ground surface have no great difference both on the diffraction waves and on the reflection waves. The lecture described in this paper introduces an attempt of improving the efficiency of the surface consistent amplitude correction by utilizing the analysis of amplitude in initial movement of the diffraction wave. 4 refs., 2 figs.

  17. Resistivity tomography using borehole of 500m in depth at the seaside site; 500m shin boring wo mochiita kaigan fukin deno hiteiko tomography tansa

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K. [Central Research Institute of Electric Power Industry, Tokyo (Japan); Kono, T. [Radioactive Waste Management Center, Tokyo (Japan); Chiba, A. [Sumitomo Metal Industries, Ltd., Osaka (Japan)

    1997-10-22

    With an objective to verify exploration methods to identify geological structures to a depth of about 500 m and continuity of fissure zones, a case study was carried out on a resistivity tomography method using ground surface exploration by means of the resistivity method and boreholes of 500 m in depth. The investigated area is consisted of abyssal rocks of the Cretaceous period, where granodiorites of coarse grain and intrusive rocks of small scale are distributed. Fissures on the ground surface have gentle inclination, and are of opening type showing high water permeability. The data analysis has derived apparent resistivities in the Wenner electrode arrangement, the Eltran electrode arrangement and the pole-pole electrode arrangement. The resistivity tomography has derived apparent resistivity in the pole-dipole electrode arrangement which is relatively high in accuracy and strong against noise. As a result of inputting these resistivities and performing an analysis on a two-dimensional resistivity structure, a structure of 100-m scale was made clear, in which difference of the resistivity values is distinct. The result of the resistivity tomography may be thought to have identified the resistivity anomaly of a small scale, although the absolute values show some variation. 4 refs., 5 figs., 2 tabs.

  18. Wave fields simulation in difficult terrain using numerical grid method; Hyoko henka no aru chiiki deno suchi koshi wo mochiita hado simulation

    Energy Technology Data Exchange (ETDEWEB)

    Jung, W.; Ogawa, T. [Yokohama National University, Yokohama (Japan); Tamagawa, T.; Matsuoka, T. [Japan Petroleum Exploration Corp., Tokyo (Japan)

    1997-10-22

    This paper describes that a high-accuracy simulation can be made on seismic exploration by using the numerical grid method. When applying a wave field simulation using the difference calculus to an area subjected to seismic exploration, a problem occurs as to how a boundary of the velocity structure including the ground surface should be dealt with. Simply applying grids to a boundary changing continuously makes accuracy of the simulation worse. The difference calculus using a numerical grid is a method to solve the problem by imaging a certain region into a rectangular region through use of variable conversion, which can impose the boundary condition more accurately. The wave field simulation was carried out on a simple two-layer inclined structure and a two-layer waved structure. It was revealed that amplitudes of direct waves and reflection waves are disturbed in the case where no numerical grid method is applied, and the amplitudes are more disperse in the reflection waves than those obtained by using the numerical grid method. 7 refs., 10 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-27

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-27

    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.

  1. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    1997-05-27

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

  3. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

  5. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

  7. FY1995 research on nonlinear optical devices using super-lattice semiconductors; 1995 nendo chokoshi active hisenkei soshi wo mochiita chokosoku hikari seigyo gijutsu no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The purpose is to develop technologies on efficient generation and control of femtosecond optical pulses using a novel semiconductor optical devices. We studied a modelocked Cr:forsterite laser pumped by a diode pumped Nd:YVO4 laser. Both Kerr lens mode locking and semi-conductor saturable absorber initiated mode locking have been achieved. The minimum pulse width for pure Kerr lens mode locking is 26.4 fs, while for the semiconductor saturable absorber initiated mode locking, the pulse width is 36 fs. The latter is very resistant to the environment perturbations. We also present the measured dispersion data for the forsterite crystal and the SESAM, and discuss the dispersion compensation technique. (NEDO)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-10

    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.

  10. Development of the LIGA process using a superconducting compact synchrotron light source; Chodendo kogata synchrotron kogen wo mochiita LIGA process no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Takada, H.; Hirata, Y.; Okuyama, H.; Numazawa, T. [Sumitomo Electric Industries, Ltd., Osaka (Japan)

    1996-11-20

    This paper is devoted to the description of the LIGA process using a 60OMeV superconducting compact synchrotron light source. The realization of deep-etch x-ray lithography is based on a new resist and mask. The resist is made of a copolymer of methyl methacrylate (MMA) and methacryl acid (MAA). The main benefit is its high sensitivity, which is one order of magnitude greater than that of polymethyl methacrylate (PMMA) used in the LIGA process. The mask is composed of a 2{mu}m thick silicon nitride membrane with high transparency supporting tungsten absorber which is a at results about deep-etch x-ray lithography, electroforming and molding 5{mu}m-thick. Experiment techniques are presented. Micro-ultrasonic transmitter obtained with these techniques is also shown. The purpose of this study is the realization of low cost micro-components for a variety of industrial applications. 7 refs., 15 figs., 1 tab.

  11. Underground cavity detection using statistical variance of subsurface radar signal. Chichu radar jushin shingo no tokeiteki bunsan hyoka wo mochiita chika kudo no kenshutsu

    Energy Technology Data Exchange (ETDEWEB)

    Taketomi, K. (Gifu National College of Technology, Gifu (Japan)); Miyazaki, Y. (Toyohahsi Univ. of Technology, Aichi (Japan). Faculty of Engineering)

    1993-06-30

    Aiming at detecting nondestructively underground cavities, metal pipes or constructions that are buried underground deeper than meters, several kinds of subsurface radar are developed. But, as to targets with electric characteristics similar to surrounding materials, it is impossible to detect them simply by only using the method that compares the sizes of the amplitudes of the reflection waves so as to detect such materials as metal pipes. In the present paper, based on introducing statistical variance, it is clarified that such targets with electric characteristics similar to surrounding materials as underground cavity may be detected by the subsurface radar. The statistical variance is calculated by cell of the Log/CFAR processing, the size of the cells in question at that time may be selected according to times of length of the cells in depth direction and the number of the data in scan direction has no effects on it. The relation between the variance of the sample experiment data and the underground structures present is investigated and the connection to the underground structures is explained, based on the results of field experiments. 8 refs., 8 figs., 3 tabs.

  12. 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

    Energy Technology Data Exchange (ETDEWEB)

    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

    2000-07-25

    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)

  13. Application of soft heating method using temperature-sensitive ferrite rod for local hyperthermia. Kanon ferrite wo mochiita soft heating ho no hyperthermia eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Matsuki, H. (Tohoku University, Sendai (Japan)); Sato, T. (Fukushima Medical School, Fukushima (Japan)); Murakami, K. (Hachinohe Institute of Technology, Aomori (Japan))

    1991-09-20

    In soft heating method, a kind of hyperthermia, a temperature-sensitive magnetic material is implanted inside body and a deep heating is performed by an induced current using AC magnetic flux. A temperature-sensitive ferrite rod, inserted into a metallic ring (Cu), was prepared as a heating unit having 2mm in diameter and 10mm in length. This unit in the appropriate magnetic field can automatically control temperatures such that the flux is concentrated on the rod and an alternating flux develops heat of the metallic ring at temperatures less or equal to Curie point, the heat of the ring, however, is reduced at temperatures around the Curie point. If the temperature characteristic (saturation temperature is 44 {degree} C) was suitable, a carcinosarcoma was transplanted into the right femoral regions of rats, cultured to grow up to appropriate size. Seven heating operations were performed, for 30 minutes twice a week. The result led to the effect that tumors whose volume were less than 1 cm {sup 3} vanished completely. 19 refs., 12 figs.

  14. Optical fiber taste sensors using potential sensitive dye coatings. Makuden'i kanjusei shikisomaku wo mochiita hikari fiber mikaku sensor

    Energy Technology Data Exchange (ETDEWEB)

    Yamakawa, S.; Yamaguchi, A. (Toyama National College of Maritime Technology, Toyama (Japan))

    1992-12-20

    The present paper proposes a new taste recognition system using optical response patterns from multi-channel optical fiber sensors having potential sensitive dye coatings. It was found that the sensors give large changes in optical absorption spectra of the dyes when they are immersed in various taste solutions. Consequently, it was shown that the sensors can be used as a taste sensor. Six dyes, which give large changes in dye absorption, were selected from twenty dyes and used for six-channel optical fiber taste sensors array. The absorption spectra change data were processed by multiple discriminant analysis and neural networks using back-propagation algorithm. From the analytical results, it was demonstrated that salty (NaCl), bitter (quinidine), sweet (sucrose), sour (HCl), and umami (sodium glutamate) substances can be recognized from each other by using the optical taste sensor system. 11 refs., 8 figs., 2 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

  16. Sixteen dot/mm thermal printing head using polyimide heat-resistant layer; Polyimide chikunetsuso wo mochiita 16 dot/mm kannetsu kiroku head kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, T.; Watanabe, M. [Hitachi, Ltd., Tokyo (Japan)

    1995-05-25

    A high-efficiency thermal printing head with a resolution of 16 dot/mm has been developed. Print power efficiency was remarkably improved by using polyimide which has low thermal conductivity and high temperature stability, as a heat-resistant layer. The thickness of the polyamide layer was optimized to ensure both high efficiency and rapid cooling by temperature response analysis of the head using the finite-element method. Experiments show that the printing power for thermal paper decreased to half of that of conventional heads with glass glaze, and the pulse durability of the head exceeded 10{sup 8} pulses within an electric resistance change of 10%. 6 refs., 11 figs., 1 tab.

  17. Development of inspection system for vehicle interior transient noise using non-stationary signal analysis; Hiteijo shingo bunseki wo mochiita sharyo ion hantei system no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, H.; Ueda, K. [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    A method to inspect the rattle, one of the transient noises of car interior, is developed. In the method, the waveform data of overall noise are analyzed using Wigner distribution, and its rattle component is condensed and separated from the background excitation noise. Then the rattle component is classified into three levels: strong, middle and none, using the neural network. A fuzzy inference is also used to select regular waveform measurements. Experimental results show that the correct classification ratio of the method is more than 90%, which equals skilled inspection operators in accuracy. 11 refs., 8 figs.

  18. 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

    Energy Technology Data Exchange (ETDEWEB)

    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))

    1992-12-20

    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.

  19. Crossflow type silicon microchannel substrate monodispersion oil-in-water emulsion manufacture; Kurosufuro gata shirikon maikuro chaneru kiban wo mochiita tanbunsan suchuyu emarushon no sakusei

    Energy Technology Data Exchange (ETDEWEB)

    Kawakatsu, Takahiro [Tohoku University, Miyagi (Japan). Graduate School; Komori, Hideai; Najima, Mitsutashi; Kikuchi, Yuji; Yonemoto, Toshikuni

    1999-05-05

    The new technique, which continuously produced the monodispersion oil-in-water (0/W) emulsion using the crossflow type silicon microchannel substrate, was developed. On the silicon monocrystal substrate, the watercourse as the liquid of the continuous phase flowed was produced, and the column of the equal slit of the size in both walls of the watercourse was precisely processed. By closing the upper part in the slit by the clamp of the flat glass board in the microchannel substrate, the microchannel column was formed. Through the microchannel, the oil droplet in which the size was even was formed by sending out the oil (triolein) in the water (0.3wt% sodium lauryl sulfate aqueous solution) of continuous phase which is flowing in respect of the watercourse. The size of the oil droplet is greatly dependent on the structure of the microchannel regulated by microchannel width, microchannel height and terrace length (the even part of which the microchannel exit was equipped). Monodispersion emulsion of 16,20 and 48 {mu}m at the average droplet diameter was formed by using microchannel substrate of the three types of which the structure differs. Droplet diameter decreased, when the substrate which formed large droplet of 48 {mu}m in which the water current quantity is 1.4x10{sup -2}mLmin{sup -1} was used, when the flow rate increased. However, there was no a flow rate at droplet diameter, even if it was made to change from 1.4x10{sup -2} to 2.4mLmin{sup -1}, 16 {mu}m 20 {mu}m small change. In all cases, the droplet size distribution was narrow, and the geometry standard deviation was under 1.03. (translated by NEDO)

  20. Development of infrared point-source light emitting diodes (LED) with a distributed Bragg reflector (DBR); Bragg hanshakyo wo mochiita sekigai ten kogen LED no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kato, T.; Saka, T.; Hirotani, M.; Sone, H. [Daido Steel Co. Ltd., Nagoya (Japan)

    1997-05-20

    It has been required to develop LED with a small point-source for optical sensors and optical encoders. To fabricate a high efficiency point-source LED, the structure and fabrication process have been considered in which the current can be focused on a small light emitting region and the light can be obtained effectively from a small window. Thus, a high output point-source LED with a light emitting diameter 50{mu}m has been developed. A Bragg reflector with AlGaAs/AlAs multi-layer film was put on the n-GaAs substrate, and n-AlGaAs/p-GaAs/p-AlGaAs double hetero-structure layer and n-AlGaAs current block layer were put on the layer in the order. For making a small point-source LED, a part of the current block layer was opened by etching, and a current path was made by diffusing Zn from the surface. A structure was made in which the current can be concentrated only in a region immediately below the light collection part of p-AlGaAs light emitting layer. The LED was deposited by the epitaxial growth on the n-GaAs substrate using a vertical-type MOCVD apparatus under the atmospheric pressure. From the results of the continuous operation test, this system was considered to have sufficient reliability for the practical use. 7 refs., 7 figs., 1 tab.

  1. Spin-Prope Investigation og the Dynamic Behavior of Law Molecule Additive in Polyvinylchloride; Supinpurobu ho wo mochiita porienkabiniru naibu ni okeru teibunshitenkazei no douteki kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Sawada, Kouhei. [NOF Corp., Hyogo (Japan)]|[Ehime University, Ehime (Japan); Onodera, Shou.; Enomoto, Hiroyuki. [NOF Corp., Hyogo (Japan). Oleochemical Reserch Laboratory; Nagaoka, Shin`ichi.; Mukai, Kazuo. [Ehime University, Ehime (Japan). Faculty of Science

    1999-03-10

    The three kinds of TEMPO radical Derivattttives (TEMPO (-H), TEMPOL (-OH), TEMPOAM (-NH{sub 2})) having defferent substiturents in the molecule as the spin probe ware added to the poly-(vinyl chloride) (PVC) including dioctuly pgthalate (DOP) as plasticiczer, and the rotational correlation times {tau}{sub C(}m) of the radical derivatives were obtained in the temperature range of 90-180degreeC by the ESR measurement. The values of T{sub c(}m) for sech radical decreased by increasing the quantity of DOP added to PVC. Simailarly, the values of {tau}{sub c}{sup (}m) decreased by increasing the temperature. The decrease of {tau}{sub c}{sup (}m) may be explained by the decrease of the density of the PVC resin and, thus, the decrease of the viscosity of PVC resin, due to the addition of DOP and the temperature. It has been cleared that the value of {tau}{sub c}{sup (}m) varies depending on the functional groups (-H, -OH, -NH{sub 2}) in TEMPO radical derivatives, indicating the existence of the nteraction berween the PVC molecule and the functional groups (-H, -OH, -NH{sub 2}) in TEMPO derivatives. The energies of the adove interactions were claculated with the UHF-PM3 method by using the MOPAC 93 program. TEMPO derivatives and DOP increases in the order of TEMPO

  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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, Makoto [Oita University, Oita (Japan)

    1999-03-05

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-25

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-25

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

    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. Fatigue life prediction of CFRP using evolution of creep property; Hiro katei ni okeru creep tokusei no henka wo mochiita CFRP no hiro jumyo yosoku

    Energy Technology Data Exchange (ETDEWEB)

    Kanagawa, Y.; Fujii, T.; Sato, A. [Nagoya University, Nagoya (Japan). Faculty of Engineering

    1996-05-15

    A damage criterion on CFRP under fatigue loading defined in terms viscoelasticity is proposed. In order to elucidate the change in viscoelastic property of CFRP composites rider cyclic loadings this to matrix hardening, matrix crack, interface debonding and delamination a series of creep tests was incorporated during monotonic tensile fatigue test. A generalized Voigt model was applied to describe the creep behavior of the damaged composites. By use of the increment of creep strain induced by internal damage growth, a damage variable was proposed in the framework of Kachanov-Ravotnov`s classical damage theory. The evolution of the damage variable in relation to the maximum stress is discussed. Lemaitre-Chaboche`s damage evolution equation was employed to estimate the fatigue life of composites successfully. 8 refs., 8 figs.

  12. Prediction of tensile fatigue life for unidirectional CFRP by using hoop winding ring; Shumaki enkan wo mochiita ichihouko CFRP no incho hiro jumyo no suitei

    Energy Technology Data Exchange (ETDEWEB)

    Nakada, Masayuki.; Miyano, Yasushi.; Kudo, Hiroshi.; Muki, Rokuro. [Kanazawa Institute of Technology, Ishikawa (Japan)

    1999-01-15

    A prediction method of fatigue strength of polymer composites for an arbitrary frequency, stress ratio, and temperature has been already proposed. The method is based upon the four hypotheses, (A) failure mechanism for CSR (constant strain-rate), creep, and fatigue failure is the same, (B) the same time-temperature superposition principle is valid for all failure strengths, (C) linear cumulative damage law is applicable for specimen failure under monoatomic loading, and (D) fatigue strength shows linear dependence on stress ratio. In this paper, tensile CSR, creep, and fatigue strengths in the longitudinal direction of unidirectional CFRP at various loading rates and temperatures were measured by the NOL ring tests. The validity of hypotheses B, C, D, and the applicability of this prediction method were confirmed by creep tests and fatigue tests of different conditions of loading rate and temperature. It was also confirmed that the hypothesis A is not always necessarily for this prediction method through discussions. (author)

  13. Improved photoelectrochemical water oxidation by the WO3/CuWO4 composite with a manganese phosphate electrocatalyst.

    Science.gov (United States)

    Nam, Ki Min; Cheon, Eun Ah; Shin, Won Jung; Bard, Allen J

    2015-10-06

    We describe a composite of the n-type semiconductors for the photoelectrochemical oxygen evolution reaction (OER). A simple drop-casting technique of mixed precursors and a one-step annealing process were used in the synthesis of the WO3/CuWO4 composite. The composite showed improved photocurrent for water oxidation compared to either of the two compounds individually. We discuss possible electron-hole separation mechanisms in two semiconductors comprising a primary photon-absorbing semiconductor of CuWO4 with a secondary semiconductor of WO3. When the WO3/CuWO4 composite is simultaneously irradiated, the photogenerated hole from the WO3 valence band transfers to CuWO4, which results in an enhanced charge separation of CuWO4. Furthermore, the OER catalytic activity of manganese phosphate (MnPO) was compared to manganese oxide nanoparticles (Mn2O3) by electrochemical measurements, showing that the manganese phosphate was more efficient for the OER reaction. To investigate the effect of catalysts on semiconductors, manganese phosphate was deposited on the WO3/CuWO4 composite. The result demonstrates the promise of manganese phosphate for improving the photocurrent as well as the stability of the WO3/CuWO4 composite.

  14. Facile Synthesis of Highly Dispersed WO3·H2O and WO3 Nanoplates for Electrocatalytic Hydrogen Evolution

    Directory of Open Access Journals (Sweden)

    Wen-Hui Hu

    2015-01-01

    Full Text Available The highly dispersed WO3·H2O nanoplates have been synthesized by a facile hydrothermal reaction assisted by citrate acid. WO3 nanoplates have been prepared by the calcination of as-prepared WO3·H2O at 450°C. XRD data show that WO3·H2O and WO3 have good crystal structure and high purity. SEM images show that WO3·H2O and WO3 have the uniform nanoplates morphology with the edge length of about 100–150 nm. The selective absorbance of citrate acid with many OH groups onto [010] facet of tungsten oxide precursors can result in the controlled growth of WO3·H2O, thus leading to the good dispersion and small size of WO3·H2O nanoplates. The electrocatalytic activity of WO3·H2O and WO3 for hydrogen evolution reaction (HER has been investigated in detail. The good electrocatalytic activity for HER has been obtained, which may be attributed to the good dispersion and small size of nanoplates. And the growth mechanisms of WO3·H2O and WO3 nanoplates have been discussed.

  15. Hydrothermal synthesis of CdWO nanorods and their ...

    African Journals Online (AJOL)

    NICO

    reactors. In the beginning, the ion of WO4. 2– is mainly located in the inner surface of the micelle. After adding. CdCl2·2.5H2O solution to the mixture, the Cd2+ ions combine with WO4. 2– to form CdWO4 crystal. The micelle wrapping limit.

  16. Molecular subgrouping of Wolbachia and bacteriophage WO ...

    Indian Academy of Sciences (India)

    2011-12-16

    Dec 16, 2011 ... Kittayapong P. 2011 Infection incidence and relative density of the bacteriophage WO-B in Aedes albopictus mosquitoes from fields in Thailand. Curr. Microbiol. 62, 816–820. Baldo L. and Werren J. H. 2007 Revisiting Wolbachia supergroup typing based on WSP: spurious lineages and discordance with.

  17. Nonlinear current-voltage characteristics of WO3-x nano-/micro-rods

    Science.gov (United States)

    Shen, Zhenguang; Peng, Zhijian; Zhao, Zengying; Fu, Xiuli

    2018-04-01

    A series of crystalline tungsten oxide nano-/micro-rods with different compositions of WO3, WO2.90, W19O55 (WO2.89) and W18O49 (WO2.72) but identical morphology feature were first prepared. Then, various nanoscaled electrical devices were fabricated from them by micro-fabrication through a focused ion beam technique. Interestingly, the devices from the oxygen-deficient WO3-x display significantly nonlinear current-voltage characteristics. The calculated nonlinear coefficients of the WO2.90, WO2.83, and WO2.72 varistors are 2.52, 3.32 and 4.91, respectively. The breakdown voltage of the WO2.90, WO2.83, and WO2.72 varistors are 1.93, 1.28 and 0.93 V, respectively. Such WO3-x nano-varistors might be promising for low-voltage electrical/electronic devices.

  18. Tuning the pure monoclinic phase of WO3 and WO3-Ag nanostructures for non-enzymatic glucose sensing application with theoretical insight from electronic structure simulations

    Science.gov (United States)

    Ponnusamy, Rajeswari; Gangan, Abhijeet; Chakraborty, Brahmananda; Sekhar Rout, Chandra

    2018-01-01

    Here, we report the controlled hydrothermal synthesis and tuning of the pure monoclinic phase of WO3 and WO3-Ag nanostructures. Comparative electrochemical nonenzymatic glucose sensing properties of WO3 and WO3-Ag were investigated by cyclic voltammetry and chronoamperometric tests. We observed enhanced glucose sensing performance of WO3-Ag porous spheres as compared to bare WO3 nanoslabs. The sensitivity of the pure WO3 nanoslabs is 11.1 μA μM-1 cm-2 whereas WO3-Ag porous spheres exhibit sensitivity of 23.3 μA μM-1 cm-2. The WO3-Ag porous spheres exhibited a good linear range (5-375 μM) with excellent anti-interference property. Our experimental observations are qualitatively supported by density functional theory simulations through investigation of bonding and charge transfer mechanism of glucose on WO3 and Ag doped WO3. As the binding energy of glucose is more on the Ag doped WO3 (100) surface compared to the bare WO3 (100) surface and the Ag doped WO3 (100) surface becomes more conducting due to enhancement of density of states near the Fermi level, we can infer that Ag doped WO3 exhibits a better charge transfer media compared to bare WO3 resulting in enhanced glucose sensitivity in consistency with our experimental data.

  19. Transforming Anodized WO3 Films into Visible-Light-Active Bi2WO6 Photoelectrodes by Hydrothermal Treatment.

    Science.gov (United States)

    Ng, Charlene; Iwase, Akihide; Ng, Yun Hau; Amal, Rose

    2012-04-05

    We directly transformed anodized tungsten oxide film (WO3·2H2O) into bismuth tungstate (Bi2WO6) by substituting the intercalated water molecules with [Bi2O2](2+) in a hydrothermal treatment. The resultant Bi2WO6 was readily used as an electrode to produce anodic photocurrent in H2 evolution on the Pt counter electrode observed under visible light irradiation.

  20. Cs2Bi(PO4(WO4

    Directory of Open Access Journals (Sweden)

    Kateryna V. Terebilenko

    2009-09-01

    Full Text Available Dicaesium bismuth(III phosphate(V tungstate(VI, Cs2Bi(PO4(WO4, has been synthesized during complex investigation in a molten pseudo-quaternary Cs2O–Bi2O3–P2O5–WO3 system. It is isotypic with K2Bi(PO4(WO4. The three-dimensional framework is built up from [Bi(PO4(WO4] nets, which are organized by adhesion of [BiPO4] layers and [WO4] tetrahedra above and below of those layers. The interstitial space is occupied by Cs atoms. Bi, W and P atoms lie on crystallographic twofold axes.

  1. Li-driven electrochemical properties of WO3 nanorods

    International Nuclear Information System (INIS)

    Wang Qiang; Wen Zhenhai; Jeong, Yeonseok; Choi, Jiyoung; Lee, Kwangyeol; Li, Jinghong

    2006-01-01

    The Li-driven electrochemical properties of monoclinic WO 3 nanorods, which are prepared by a solution-based colloidal approach, have been studied, and the relationship between the properties and the nanostructures of the material has been established. The electrochemical reactions towards lithium involved in WO 3 nanorods were investigated by means of a galvanostatic method and an impedance technique, and superior characteristics associated with one-dimensional nanostructures were observed. WO 3 nanorods with a high aspect ratio were found to yield an intercalation capacity up to 1.12 Li per formula unit, much higher than the value of 0.78 Li per formula unit for bulk WO 3 . This can be explained on the basis of the unique rod-like structure that effectively enhanced structure stability. The evolution of Li-driven reaction kinetics further illustrated benefits of WO 3 nanorods owing to the increased edge and corner effects

  2. Visible-Near-Infrared-Light-Driven Oxygen Evolution Reaction with Noble-Metal-Free WO2-WO3 Hybrid Nanorods.

    Science.gov (United States)

    Wang, Song Ling; Mak, Yan Lin; Wang, Shijie; Chai, Jianwei; Pan, Feng; Foo, Maw Lin; Chen, Wei; Wu, Kai; Xu, Guo Qin

    2016-12-13

    Understanding and manipulating the one half-reaction of photoinduced hole-oxidation to oxygen are of fundamental importance to design and develop an efficient water-splitting process. To date, extensive studies on oxygen evolution from water splitting have focused on visible-light harvesting. However, capturing low-energy photons for oxygen evolution, such as near-infrared (NIR) light, is challenging and not well-understood. This report presents new insights into photocatalytic water oxidation using visible and NIR light. WO 2 -WO 3 hybrid nanorods were in situ fabricated using a wet-chemistry route. The presence of metallic WO 2 strengthens light absorption and promotes the charge-carrier separation of WO 3 . The efficiency of the oxygen evolution reaction over noble-metal-free WO 2 -WO 3 hybrids was found to be significantly promoted. More importantly, NIR light (≥700 nm) can be effectively trapped to cause the photocatalytic water oxidation reaction. The oxygen evolution rates are even up to around 220 (λ = 700 nm) and 200 (λ = 800 nm) mmol g -1 h -1 . These results demonstrate that the WO 2 -WO 3 material is highly active for water oxidation with low-energy photons and opens new opportunities for multichannel solar energy conversion.

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

    DEFF Research Database (Denmark)

    Ahmadi, Majid; Sahoo, Satyaprakash; Younesi, Reza

    2014-01-01

    Tungsten oxide (WO3) nano-ribbons (NRs) were obtained by annealing tungstite (WO3·H2O) NRs. The latter was synthesized below room temperature using a simple, environmentally benign, and low cost aging treatment of precursors made by adding hydrochloric acid to diluted sodium tungstate solutions (......2WO4·2H2O). WO3 generates significant interests and is being used in a growing variety of applications. It is therefore important to identify suitable methods of production and better understand its properties. The phase transformation was observed to be initiated between 200 and 300 °C......, and the crystallographic structure of the NRs changed from orthorhombic WO3·H2O to monoclinic WO3. It was rigorously studied by annealing a series of samples ex situ in ambient air up to 800 °C and characterizing them afterward. A temperature-dependent Raman spectroscopy study was performed on tungstite NRs between minus...... 180 and 700 °C. Also, in situ heating experiments in the transmission electron microscope allowed for the direct observation of the phase transformation. Powder X-ray diffraction, electron diffraction, electron energy-loss spectroscopy, and X-ray photoelectron spectroscopy were employed...

  4. Magnetic and structural properties of NaLnMnWO6 and NaLnMgWO6 perovskites

    International Nuclear Information System (INIS)

    King, Graham; Wayman, Lora M.; Woodward, Patrick M.

    2009-01-01

    We have prepared 14 new AA'BB'O 6 perovskites which possess a rock salt ordering of the B-site cations and a layered ordering of the A-site cations. The compositions obtained are NaLnMnWO 6 (Ln=Ce, Pr, Sm, Gd, Dy, and Ho) and NaLnMgWO 6 (Ln=Ce, Pr, Sm, Eu, Gd, Tb, Dy, and Ho). The samples were structurally characterized by powder X-ray diffraction which has revealed metrically tetragonal lattice parameters for compositions with Ln=Ce, Pr and monoclinic symmetry for compositions with smaller lanthanides. Magnetic susceptibility vs. temperature measurements have found that all six NaLnMnWO 6 compounds undergo antiferromagnetic ordering at temperatures between 10 and 13 K. Several compounds show signs of a second magnetic phase transition. One sample, NaPrMnWO 6 , appears to pass through at least three magnetic phase transitions within a narrow temperature range. All eight NaLnMgWO 6 compounds remain paramagnetic down to 2 K revealing that the ordering of the Ln 3+ cations in the NaLnMnWO 6 compounds is induced by the ordering of the Mn 2+ sub-lattice. - Graphical abstract: Evidence for multiple magnetic phase transitions in the A and B-site ordered perovskite NaPrMnWO 6 .

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-01

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

  6. WO3 Nanoplates Film: Formation and Photocatalytic Oxidation Studies

    Directory of Open Access Journals (Sweden)

    Chin Wei Lai

    2015-01-01

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

  7. In-situ transmission electron microscopy imaging of formation and evolution of LixWO3 during lithiation of WO3 nanowires

    International Nuclear Information System (INIS)

    Qi, Kuo; Li, Xiaomin; Sun, Muhua; Huang, Qianming; Wei, Jiake; Xu, Zhi; Wang, Wenlong; Bai, Xuedong; Wang, Enge

    2016-01-01

    The phase transition from monoclinic WO 3 to cubic Li x WO 3 during lithiation of WO 3 is one of the key features for tungsten oxide as the most used electrochromic material. Conventionally, the lithium intercalation of WO 3 has been studied by building generic layered electrochromic device combining with structural characterization and electrochemistry measurement at macro scale. In-situ transmission electron microscopy (in-situ TEM) has been proposed as a method for revealing the detailed mechanism of structural, physical, and chemical properties. Here, we use in-situ TEM method to investigate the formation and evolution of Li x WO 3 in real-time during the electrochemical lithiation of WO 3 nanowires. The dynamic lithiation process is recorded by TEM imaging, diffraction, and electron energy loss spectroscopy. The WO 3 -Li x WO 3 phase boundary of reaction front has been observed at high resolution. The timeliness of crystallinity of Li x WO 3 and the intercalation channels for Li ions are also identified. Moreover, the co-existence of both polycrystalline Li-poor area and amorphous Li-rich phases of Li x WO 3 was found. Our results provide an insight into the basic lithiation process of WO 3 , which is significantly important for understanding the electrochromic mechanism of tungsten oxide.

  8. Structure and photocatalytic performance of layered HNbWO6 nanosheet aggregation

    KAUST Repository

    Hu, Li-Fang

    2015-12-10

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

  9. Quartz roughness affect on WO3 coated QCM

    International Nuclear Information System (INIS)

    Georgieva, V; Raicheva, Z; Grechnikov, A; Gadjanova, V; Atanassov, M; Lazarov, J; Manolov, E

    2010-01-01

    The influence of the initial quartz roughness on the WO 3 -QCM (Quartz Crystal Microbalance) parameters and sorption properties was investigated. Experiments were carried out using AT-cut quartz crystal with different surface roughness obtained after treatment with SiC abrasive having grain size of 3 μm, 7 μm, 14 μm and 20 μm respectively. The QCMs were covered with thin WO 3 films. The equivalent dynamic parameters of the WO 3 - QCM were measured and a correlation with the surface roughness was determined. The equivalent dynamic resistance of the as-created QCM increases from 15.42 Ω to 117 Ω and the quality factor decreases as a result of the roughness changes. The surface morphology was observed by a Scanning Electron Microscopy (SEM), which showed higher increase of the WO 3 surface roughness compared to those of the initial quartz surface. The cross-section profiles of the investigated structures show different overlay of Au-electrodes. The sorption properties of WO 3 -QCM system to NH 3 were studied in the range from 10 ppm to 1000 ppm. The response and recovering times were determined. The experimental results show an increase of the sorption ability with the increase of the initial quartz roughness. By increasing the roughness the mass-loading is improved.

  10. Correlations among structure, composition and electrochemical performances of WO3 anode materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Li, Pu; Li, Xing; Zhao, Ziyan; Wang, Mingshan; Fox, Thomas; Zhang, Qian; Zhou, Ying

    2016-01-01

    Highlights: • The residual precursor ions affect the charge/discharge performances of WO 3 . • Lithiated monoclinic WO 3 reveals the best discharge capacity. • Lithiation can enhance the conductivity of WO 3 . - Abstract: Suitable host structure for lithium insertion and extraction is crucial for lithium-ion batteries. Tungsten trioxides (WO 3 ) are particularly interesting materials for this purpose. In this work, the influences of structure and composition of WO 3 on the charge/discharge performances of Li-ion batteries are systematically investigated. Firstly, lithiated tungsten trioxides (Li-WO 3 ) are successfully synthesized by a hydrothermal method followed by annealing at different temperatures (200–600 °C). It is found that the hexagonal framework collapses and gradually transforms to the monoclinic phase due to the release of NH 4 + and NH 3 molecules. Unexpectedly, monoclinic WO 3 reveals better performances than that of hexagonal WO 3 . Among all the investigated samples, the lithiated WO 3 annealed at 500 °C exhibits the highest discharge capacity and cycle performance (703 mAh g −1 after 10 cycles). We believe that the Li + remained in the solid structure of WO 3 can lead to a more stable structure. In addition, Li + could inhibit the oxidation of W 5+ during the heat treatment process, which increases the electron conductivity of WO 3 . Our results indicate that the electrochemical properties of WO 3 are strongly related to the residual precursor and crystal structure.

  11. The chemistry of ZnWO4 nanoparticle formation

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  12. Reflectivity modulation with LixWO3 thin films

    International Nuclear Information System (INIS)

    Arntz, F.O.; Berera, G.; Goldner, R.B; Haas, T.E.; Moprel, B.

    1990-01-01

    One potentially improtant application for electrochromic (and other solid-state ionic)thin films is as the electrochemically-controlled reflectivity-modulated layer in smart window glass (or smart windows). In principle, smart windows can be operated in either of two modes: absorptivity modulation or reflectivity modulation. The feasibility of utilizing polycrystalline (pc) tungsten bronze films, M x WO 3 (M = H, Li), to obtain spectrally selective reflectivity modulation has been previously demonstrated. The question addressed in this paper is to determine the upper bound for the near infrared reflectivity modulation of pc-Li x WO 3 films

  13. Facile Hydrogen Evolution Reaction on WO3Nanorods

    Directory of Open Access Journals (Sweden)

    Rajeswari Janarthanan

    2007-01-01

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

  14. Intrinsic Defects and H Doping in WO3

    KAUST Repository

    Zhu, Jiajie

    2017-01-18

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

  15. Surface oxygen vacancies on WO{sub 3} contributed to enhanced photothermo-synergistic effect

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yingying; Wang, Changhua; Zheng, Han; Wan, Fangxu; Yu, Fei; Zhang, Xintong, E-mail: xtzhang@nenu.edu.cn; Liu, Yichun

    2017-01-01

    Graphical abstract: WO{sub 3−x} acts as efficient and stable photothermocatalyst for detoxification of gaseous acetaldehyde. - Highlights: • WO{sub 3} was annealed under air and hydrogen atomsphere. • Phase transition from WO{sub 3} to WO{sub 2.72} to WO{sub 2} was observed after hydrogen treatment. • WO{sub 3−x} with optimized degree of oxygen deficiency displayed significant photothermocatalytic activity against degradation of acetaldehyde. • Mechanism operating in photocatalytic and thermal effects is discussed. - Abstract: 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 WO{sub 3} subjected to hydrogen treatment as photothermocatalyst. With the increase of hydrogen treatment temperature, the color of WO{sub 3} changes from yellow to blue to dark blue and a phase transition from WO{sub 3} to WO{sub 2.72} to WO{sub 2} 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 WO{sub 3−x} sample with low concentration of oxygen vacancy displays the most significant synergetic effect between photocatalysis and thermocatalysis. Its photothermocatalytic activity in terms of CO{sub 2} evolution rate is 5.2 times higher than that of photocatalytic activity. However, WO{sub 3}–WO{sub 2.72} and WO{sub 2} 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.

  16. Experimental study of seismic retrofit technique. Pt. 2. Using hysteretic steel dampers for existing RC buildings; Dansosei damper wo mochiita kison RC tatemono no seishin hokyo koho ni kansuru jikken kenkyu. 2. Kisonbu tono setsugoho wo kanryakukashita koho to ryosoku kaiko wo yusuru kanchu koho no kozo seino

    Energy Technology Data Exchange (ETDEWEB)

    Tagami, J.; Ishii, K.; Koshika, N.; Kurokawa, Y.; Kunisue, A.; Shimizu, K. [Kajima Corp., Tokyo (Japan)

    1999-09-30

    The writers have proposed a seismic retrofit technique using honeycomb dampers as a method for securing high safety with less reinforcing planes compared with conventional anti-earthquake reinforcements. As reported previously, in grasping the reinforcing effect of the two typical methods, a structural experiment was implemented using frame specimens through a scale-down to 1/2 size, confirming the effect for improving the bearing force of existing frames and the absorbing capacity of hysteresis energy, in the new reinforcing method of newly installing steel reinforcing frames with dampers. In this paper, possibility was investigated of simplifying a joining method in connection with the new technique, by carrying out an additional experiment which enabled the resulting effect to be grasped in the simplification of joining an existing part with steel reinforcing frames. In addition, a similar experiment was conducted on the new construction method using intermediate posts, on an assumption that an opening on both sides is secured inside a reinforcing retrofit plane, while a comparison was made with other methods in performance. As a result of the examination, concerning the method of newly installing vibration control frames, it became evident that these specimens with the joining method simplified can demonstrate a reinforcing effect comparable to the structural performance of the old specimens which used a conventional joining detail in anti-earthquake reinforcement. Concerning the balloon frame construction method, a fairly satisfactory reinforcing effect was also confirmed despite problems left on the details. (translated by NEDO)

  17. Research on the preparation of highly functional ceramics aiming at fusing together with living cells. Pt. 1. Application for biomaterial; Seitai saibo tono yugo ka wo mezashitaa kokinosei ceramics sosei gijutsu ni kansuru kenkyu. 1. Seibutesugakuteki shuho wo mochiita zairyo kaihatsu wo mezashit

    Energy Technology Data Exchange (ETDEWEB)

    Inagaki, H.; Maeda, S.; Kato, K.; Saito, T. [National Industrial Research Institute of Nagoya, Nagoya (Japan)

    2000-03-06

    We isolated the gene of Bone Morphogenic Proteins-1 (BMP-1) by RT-PCR (Reverse Transcriptase Polymerase Chain Reaction), and produced BMP-1 protein for the industrial application. We clarified theroles of BMP-2 and BMP-4, which are other members of BMPs, in cardiovascular formation at an early stage of embryo. In addition, we isolated a novel gene from bone mRNA and termed it rDLG-6. From the sequence comparisons by the BLASTX program, we found that rDLG 6 is a member of MAGUK (Membrane Associated Guanylate Kinase) family. (author)

  18. Transparency and radiation hardness of Cherenkov crystals NaBi(WO4)2:Sc

    International Nuclear Information System (INIS)

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

    2001-01-01

    The effects of doping the Cherenkov crystal NaBi(WO 4 ) 2 with Sc ions on the optical properties and radiation hardness of this crystal have been studied. The radiation hardness of NaBi(WO 4 ) 2 :Sc is about 3 times higher than that of undoped NaBi(WO 4 ) 2 . Analytical estimations give the increase of the number of Cherenkov photons by a factor of 1.3, which leads to an improvement of the energy resolution of a calorimeter based on NaBi(WO 4 ) 2 :Sc crystals compared with undoped NaBi(WO 4 ) 2 of approximately 15%

  19. HRTEM Microstructural Characterization of ?-WO3 Thin Films Deposited by Reactive RF Magnetron Sputtering

    OpenAIRE

    Faudoa-Arzate, A.; Arteaga-Dur?n, A.; Saenz-Hern?ndez, R.J.; Botello-Zubiate, M.E.; Realyvazquez-Guevara, P.R.; Matutes-Aquino, J.A.

    2017-01-01

    Though tungsten trioxide (WO3) in bulk, nanosphere, and thin film samples has been extensively studied, few studies have been dedicated to the crystallographic structure of WO3 thin films. In this work, the evolution from amorphous WO3 thin films to crystalline WO3 thin films is discussed. WO3 thin films were fabricated on silicon substrates (Si/SiO2) by RF reactive magnetron sputtering. Once a thin film was deposited, two successive annealing treatments were made: an initial annealing at 400...

  20. Cr2O3 nanoparticle-functionalized WO3 nanorods for ethanol gas sensors

    Science.gov (United States)

    Choi, Seungbok; Bonyani, Maryam; Sun, Gun-Joo; Lee, Jae Kyung; Hyun, Soong Keun; Lee, Chongmu

    2018-02-01

    Pristine WO3 nanorods and Cr2O3-functionalized WO3 nanorods were synthesized by the thermal evaporation of WO3 powder in an oxidizing atmosphere, followed by spin-coating of the nanowires with Cr2O3 nanoparticles and thermal annealing in an oxidizing atmosphere. Scanning electron microscopy was used to examine the morphological features and X-ray diffraction was used to study the crystallinity and phase formation of the synthesized nanorods. Gas sensing tests were performed at different temperatures in the presence of test gases (ethanol, acetone, CO, benzene and toluene). The Cr2O3-functionalized WO3 nanorods sensor showed a stronger response to these gases relative to the pristine WO3 nanorod sensor. In particular, the response of the Cr2O3-functionalized WO3 nanorods sensor to 200 ppm ethanol gas was 5.58, which is approximately 4.4 times higher that of the pristine WO3 nanorods sensor. Furthermore, the Cr2O3-functionalized WO3 nanorods sensor had a shorter response and recovery time. The pristine WO3 nanorods had no selectivity toward ethanol gas, whereas the Cr2O3-functionalized WO3 nanorods sensor showed good selectivity toward ethanol. The gas sensing mechanism of the Cr2O3-functionalized WO3 nanorods sensor toward ethanol is discussed in detail.

  1. Investigation of W/O microemulsion droplets by contrast variation ...

    Indian Academy of Sciences (India)

    Dynamic and static light scattering experiments have been performed at various molar ratios () of water to AOT and temperatures on water-in-oil (W/O) microemulsions dispersed in n-heptane, n-octane, and n-nonane. Size and shape fluctuations of microemulsion droplets are determined with very high precision because ...

  2. Characterisation and application of WO3 films for electrochromic devices

    Science.gov (United States)

    Stapinski, Thomas; Marszalek, Konstanty; Swatowska, Barbara; Stanco, Agnieszka

    2013-07-01

    Electrochromic system is the one of the most popular devices using color memory effect under the influence of an applied voltage. The electrochromic system was produced based on the thin WO3 electrochromic films. Films were prepared by RF magnetron sputtering from tungsten targets in a reactive Ar+O2 gas atmosphere of various Ar/O2 ratios. The technological gas mixture pressure was 3 Pa and process temperature 30°C. Structural and optical properties of WO3 films were investigated for as-deposited and heat treated samples at temperature range from 350°C to 450°C in air. The material revealed the dependence of properties on preparation conditions and on post-deposition heat treatment. Main parameters of thin WO3 films: thickness d, refractive index n, extinction coefficient k and energy gap Eg were determined and optimized for application in electrochromic system. The main components of the system were glass plate with transparent conducting oxides, electrolyte, and glass plate with transparent conducting oxides and WO3 layer. The optical properties of the system were investigated when a voltage was applied across it. The electrochromic cell revealed the controllable transmittance depended on the operation voltage.

  3. Enhanced photocatalytic properties in well-ordered mesoporous WO3

    KAUST Repository

    Li, Li

    2010-01-01

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

  4. Electrochromic properties of electrodeposited tungsten oxide (WO3) thin film

    Science.gov (United States)

    Dalavi, D. S.; Kalagi, S. S.; Mali, S. S.; More, A. J.; Patil, R. S.; Patil, P. S.

    2012-06-01

    In this work, we report on a potentiostatic electrochemical procedure employing an ethanolic solution of peroxotungstic acid yielded tungsten oxide (WO3) films specifically for transmissive electrochromic devices (ECDs) such as "smart windows". WO3 film was confirmed from the binding energy determination by X-ray photoelectron spectroscopic studies. The diffusion coefficient during intercalation and deintercalation was found to be 2.59×10-10 and 2.40×10-10 cm2/C. Electrodeposited WO3 produce high color/bleach transmittance difference up to 74% at 630 nm. On reduction of WO3, the CIELAB 1931 2% color space coordinates show the transition from colorless to the deep blue state (L=95.18, a=2.12, b=0.3138, and L=57.78, a=-21.79, b=0.244) with steady decrease in relative luminance. The highest coloration efficiency (CE) of 92 cm2/C and good response time of 10.28 for coloration (reduction) and 3.2 s for bleaching (oxidation) was observed with an excellent reversibility of 89%.

  5. WO/sub 3/ thin films for practical electrochromic windows

    International Nuclear Information System (INIS)

    Goldner, R.B.; Wong, K.; Foley, G.; Norton, P.; Wamboldt, L.; Seward, G.; Haas, T.; Chapman, R.

    1986-01-01

    This paper shows that practical spectrally-selective transmittance modulation can be achieved with thin (50-100nm) WO/sub 3/ films, and therefore such films should be useful for fabricating electrochromic windows. The transmittance and reflectance modulation results are compared with theoretical predictions. The results indicate an excess intraband absorptance, which is attributed to free electron scattering arising from extended defects

  6. Investigation of W/O microemulsion droplets by contrast variation ...

    Indian Academy of Sciences (India)

    various molar ratios (µ) of water to AOT and temperatures on water-in-oil (W/O) mi- croemulsions dispersed in n-heptane, ... tures composed of surfactant, water, and oil have attracted much interest since they form thermodynamically stable phases .... filter into dust-free sample cells. The cylindrical sample cells are made of ...

  7. Estimation of site effects in Higashinada Ward, Kobe City using aftershock records of the 1995 Hyogo-Ken Nanbu Earthquake; Hyogoken nanbu jishin no yoshin kiroku wo mochiita Kobeshihigashinadaku no jiban zofuku tokusei no hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, K.; Yamanaka, H.; Seo, K. [Tokyo Inst. of Tech. (Japan)

    1998-07-30

    Source spectra and site effects are separated using the aftershock records, and the characteristics of short period earthquake motion in Higashinada Ward, Kobe City including the area to the south of seismic intensity 7 area are investigated placing emphasis on how far the site effects can be explained by 1-D ground structure. The shape and amplitude of the site effect of KNN and KYC located outside the seismic intensity 7 area can be explained fairly well by 1-D multiple reflection theory of S wave. However, peaks near 3 to 4Hz of KNN and UOZ in seismic intensity 7 area can not be explained. This suggests that the site effects of seismic intensity 7 area obtained by the aftershock records might include 2-D effects of underground structure. Inversion is performed using site effects as the objective functions to determine S wave velocity structure and Qs in the sedimentary layer. S wave velocity structure shows no systematical difference from those of the past models. 22 refs., 13 figs., 2 tabs.

  8. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-02-01

    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.

  9. Synthetic focused array of electrical prospecting using pole-pole array potential data; Sanjigen denki tansaho ni okeru nikyokuho den`i data wo mochiita denryu shusoku haichi no goseiho

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1997-10-22

    Various methods have been put into practice for the conventional two-dimensional pole configuration using a single line in three-dimensional electrical prospecting. Pole configuration effective for the three-dimensional exploration has not been investigated. This paper describes synthetic focused array using four pairs of guarded poles based on pole-pole array potential data in the case of arrangement of measuring points on a grid. Results of the numerical simulation are also described. For the focused array, laterolog of electrical logging is applied to the surface prospecting. Directivity can be given to the current from the main pole by controlling the current from guarded pole. It was found from the simulation that the resistivity anomaly is concentrated directly on the embedded ball for the focused array rather than for the pole-pole array. It was also found that two conductive balls can be clearly separated for the focused array rather than for the dipole-dipole array. Accordingly, it was considered that results approximating the original structures can be obtained by analyzing using the both arrays. 5 refs., 6 figs.

  10. Study on deep crustal resistivity structure using wideband magnetotellurics. In the case of eastern part of Hokkaido, Japan; Kotaiiki MT ho wo mochiita shinbu chikakuhi teiko kozo no kenkyu. Hokkaido Tobu chiiki ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Sato, H.; Tanimoto, K.; Maeda, T.; Nishida, Y. [Hokkaido University, Sapporo (Japan); Takada, M.; Tamura, M. [Hokkaido University, Sapporo (Japan). Research Center of Earthquake Prediction; Ogawa, Y. [Geological Survey of Japan, Tsukuba (Japan); Nagao, T. [Tokai Univ., Tokyo (Japan)

    1997-10-22

    Wide-range MT (magnetotelluric) observation is conducted to collect knowledge of the middle and lower parts of the crust of the above-named region, about which but a little information is available, for comparison with information about Kurile islands arc tectonics. Three traverse lines crossing the Kurile islands roughly in the north-south direction and two lines running from east to west are used, with the observation stations totalling 48. The distance between observation stations is 7-8km on the Nijibetsu line, and approximately 15km on the Nakashibetsu and Akan lines. A very wide frequency range of 320-0.0005Hz is used for measuring, and these results in detection with success of resistivity structure details from shallow to deep layers in the crust. The collected data are analyzed, and it is estimated that the northern and central parts have a high-low-high three-layer structure while the southern part has a low-high two-layer structure. Since the data obtained at observation stations at the middle of the lines, in particular, have an extremely low apparent value of several ohm/m at about 1Kz in the absence of splits in the TM (transverse magnetic) and TE (transverse electric) modes, it is inferred that the low-resistivity layer is considerably thick and is distributed rather uniformly. 13 refs., 5 figs.

  11. Fundamental study on the interpretation technique for 3-D MT data using neural networks. 2; Neural network wo mochiita sanjigen MT ho data kaishaku gijutsu ni kansuru kisoteki kenkyu. 2

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-22

    Behavior of neural networks relative to noise and the constitution of an optimum network are studied for the construction of a 3-D MT data interpretation system using neural networks. In the study, the relationship is examined between the noise level of educational data and the noise level of the neural network to be constructed. After examination it is found that the neural network is effective in interpreting data whose noise level is the same as that of educational data; it cannot correctly interpret data that it has not met in the educational stage even if such data is free of noise; that the optimum number of neurons in a hidden layer is approximately 40 in a network architecture using the current system; and that the neuron gain function enhances recognition capability when a logistic function is used in the hidden layer and a linear function is used in the output layer. 2 refs., 7 figs., 2 tabs.

  12. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-27

    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.

  13. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-27

    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.

  14. Study on solar chemical heat pump system. Basic experiment on dehydrogenation of 2-propanol using heteropoly-acid photo catalyst; Solar chemical heat pump no kenkyu. Heteropoly sankei hikari shokubai wo mochiita 2-propanol no dassuiso hanno

    Energy Technology Data Exchange (ETDEWEB)

    Doi, T. [Electrochemical Laboratory, Tsukuba (Japan); T-Raissi, A.; Muradov, N. [Florida Solar Energy Center, FL (United States)

    1996-10-27

    With the purpose of converting solar heat energy to an industrial heat energy, an examination was carried out empirically on the case of using a heteropoly-acid photo catalyst for the decomposition reaction process of 2-propanol. The experiment was performed in Florida Solar Energy Center, in the U.S.A.. The device for the experiment was constituted of a reaction part, distribution manifold for feeding from the lower part of the reaction part a 2-propanol solution for which a photo catalyst was suspended, storage tank served also as a gas-liquid separating container, and circulating pump. Silica-tangstic acid was used as the photo catalyst. In an outdoor experiment using solar radiation, the quantity of inclined global solar radiation was 530-950W/m{sup 2} in clear days and 100-600W/m{sup 2} in cloudy days, with temperatures between 17 and 26{degree}C throughout the experiment period. In addition, an indoor experiment was also conducted using an artificial light source (UV light). As a result of the experiment, the energy conversion efficiency was at most about 1% of incident UV light, a low figure compared to a heat utilization ratio of approximately 15% with a thermal catalyst. 6 refs., 8 figs.

  15. Palladium-catalyzed [3+2] cycloaddition of trimethylenemethane with p-benzoquinones; Parajiumu shokubai wo mochiita torimechiren metan to p-benzokinon rui tono [3+2] fukakanka hanno

    Energy Technology Data Exchange (ETDEWEB)

    Mukawa, T.; Shiraishi, S. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

    2000-01-10

    The reaction of trimethylenemethane with various alkyl-substituted p-benzoquinones was investigated. The reaction of 2,5-di-tert-butyl-p-benzoquinone with 2-(trimethylsilylmethyl) allyl acetate (1) was conducted with palladium (0) as a catalyst to afford 1 : 1-C=C-cycloadduct 2 in good yield. Similarly, 1 : -C=C-cycloadducts 3, 4, 5 and 6 were obtained with 2,6-di-tert-butyl-p-benzoquinone, 2,3,5,6-tetramethyl-p-benzoquinone, 2,3,5-trimethyl-p-benzoquinone and 2-methyl-1,4-naphthoquinone, respectively. On the other hand, the reaction with methyl-p-benzoquinone afforded the complicated mixture. As is the case with Diels-Alder reactions, the cycloaddition of trimethylenemethane with p-benzoquinones occurred towards C-C double bond. So, the reaction of trimethylenemethane with substituted p-benzoquinones is effective in the synthesis of methylenecyclopentane-fused cyclohexenediones having various substituents. (author)

  16. Solubility of triolein in supercritical carbon dioxide by using continuous flow system and correlation with pressure, temperature and density; Ryutsushiki sochi wo mochiita chorinkai nisanka tanso chu no toriorein no yokaido no sokutei to atsuryoku, ondo, mitsudo joken tono sokan

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, K.; Tao, K.; Imai, M.; Suzuki, I. [Nihon Univ., Tokyo (Japan). Dept. of Food Science and Tech.

    2000-11-10

    The Solubility of triolein in supercritical carbon dioxide (SCCO{sub 2}) was measured by a continuous flow system at various temperatures (313, 323, 333 and 343 K) and pressures (15, 20 and 25 MPa). The solubility of triolein increases with experimental pressure. The obtained data were compared with previous investigations. At 15 MPa, the solubility is considerably governed by temperature (343-313 K), i. e. 10{sup 2} - fold change of solubility. On the other hand, at 25 MPa, which is fully mature supercritical conditions, the influence of temperature on the solubility become weaker. Under constant pressure conditions, solubility of triolein decreases gradually with increasing temperature. Solubility is correlated well with the estimated density according to Bender (1970). (author)

  17. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-28

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    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. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

  20. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-27

    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.

  1. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-20

    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.

  2. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-10

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-28

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

  4. Evaluation of aerodynamic stability and a trial study of construction-accuracy control by daytime measurement of Meiko West Bridge; Meiko Nishi Ohashi no taifusei kento to chukan keisoku kekka wo mochiita kasetsu seido kanri no shiko

    Energy Technology Data Exchange (ETDEWEB)

    Morimoto, C.; Shimodoi, H.; Isoe, A.; Sakai, Y.; Ochiai, M.; Watabe, T.; Ebihara, R. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1998-12-20

    The new Meiko West Bridge was constructed very closely to the phase I line bridge which have been already in a service from 1985, and the distance of this world unique parallel cable-stayed bridges is 50m. The length, span and pylon height of these bridges are identical. By conducting wind tunnel experiments considering the aerodynamic interference of the close parallel bridges, the aerodynamic stability of the bridge had been confirmed during construction as well as complete state. After the construction was completed, the important wind characteristics of the parallel cable-stayed bridges were obtained from the site observation. Regarding cable vibrations, a common problem with cable-stayed bridges, a suitable vibration suppression method was applied based on the site observation. In general, the construction-accuracy control is performed by doing measurement at night However, to study the possibility of the accuracy-control by daytime measurement the measurement was conducted not only at night but also in the daytime. (author)

  5. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-10

    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.

  6. 3-D eddy current analysis of RF magnetic induction type hyperthermia using a large ferrite core in troidal shape. Kanjo ferrite core wo mochiita yudo kaongata hyperthermia no sanjigen uzu denryu kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Y.; Yamazaki, K.; Ishiyama, A. (Waseda Univ., Tokyo (Japan))

    1991-09-20

    In non-invasive hyperthermia, it is difficult to heat only deep and selected region with carcinosarcoma. To solve the problem, an RF inductive heating method was so designed to use a large ferrite core in troidal shape and bolus. This method can cause the eddy current concentrated on the deep region. A characteristics of the heating method was analyzed by a finite element method to study a possibility of deep and selective heating with experiments. The body is inserted through the ferrite core in troidal shape and the core is surrounded by the bolus, filled with a saline solution. The eddy current, generated around the core by AC, partially passes from the bolus to the body and is cut to avoid heating of the undesired location by an insulating film or by cutting away a part of the bolus. An effect of selective heating can be expected with appropriate adjustment of the current path. The result is based on the comparison between the experiment using phantom for axially symmetric model and the 3-D analysis, the result analyzed by a simple human body model. 9 refs., 11 figs., 2 tabs.

  7. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

  8. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

  9. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

  10. Report on achievements in fiscal 1998. Development of foaming eco-material using magazine waste papers. (The first fiscal year); 1998 nendo zasshi koshi wo mochiita happo seikei eko material no kaihatsu seika hokokusho (dai 1 nendo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Such foaming materials as styro-foam, urethane and polyethylene greatly increase load on the environment when discarded, and are a problem as harmful rubbish. On the other hand, magazine waste papers have limitation as regenerated paper because their pulp fibers are cut off and deteriorated during use and regeneration. They are left unused without a prospect of re-use even if recovered. Under such a background, the present research and development is intended to develop magazine waste papers as a reusable cushioning material, commercialize the cushioning material as a low environment load type material, and promote reutilization of magazine waste papers. Specifically, development is performed on a manufacturing technology and a manufacturing equipment for a cushioning material having excellent biodegradation performance manufactured by mixing magazine waste papers with gelatin as a binder, and further by foaming and forming. The research and development items include: (1) development of a manufacturing technology for a foaming eco-material using magazine waste papers, (2) development of manufacturing equipment for the foaming eco-material, and (3) the market research thereon. This paper reports the achievements in the research and development of each item in fiscal 1998. (NEDO)

  11. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

    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.

  12. Experimental consideration on the contact resistance caused by the distribution of contact spots with the contact model using electrolyte bath; Denkai yokuso wo mochiita sesshoku model ni yoru sesshokuten no bunpu to sesshoku teiko tokusei ni kansuru jikkenteki kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Aichi, H. [Daido Institute of Technology, Aichi (Japan); Miyachi, I. [Aichi Institute of Technology, Aichi (Japan)

    1996-09-20

    Electric contact members are classified by the form such as a point, a line, and a plane. Particularly, the point contact member which makes a small circular contact spot is basis of the contact form. Also, the plane contact member will make many contact spots which are different in size and distributing over the contacting portion. Authors have been developing the contact model to measure the contact resistance. In this model, it is available to select the size, the number, and the arrangement of contact spots by the macroscopical contact spots which are formed with some metal electrodes arranged in electrolyte solution of dilute sulfuric acid. In this paper, the fundamental characteristics of the contact resistance caused by the construction of current are investigated with 1 to 3 contact spot models. Then the relations between the contact resistance and the distribution of the contact spots are examined with 2 to 9 multi-contact spot models. As the results, it is cleared that the proposed contact model presents the successful experimental method for the analysis of the contact resistance. 9 refs., 8 tabs.

  13. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-05-10

    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)

  14. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

    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.

  15. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    1997-05-20

    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.

  16. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-16

    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)

  17. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-25

    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.

  18. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-25

    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.

  19. Consideration of the reservoir by the temperature history at the Hijiori HDR (hot dry rock) wells; Hijiori koon gantai no kokukosei ni okeru ondo rireki wo mochiita choryuso no kosatsu

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-22

    Hot dry rock (HDR) power generation has been promoted by NEDO since 1984 at Hijiori, Okura village, Mogami-gun, Yamagata Prefecture. Hydraulic fracture tests and circulation tests have been conducted using four wells named as SKG-2, HDR-1, HDR-2 and HDR-3. Based on these test results, flow models of Hijiori shallow and deep reservoirs have been proposed. Conventional circulation tests have been analyzed only using temperature profile data. In this paper, circulation tests are analyzed by numerical simulation, to discuss individual characteristics of the shallow and deep reservoirs. Injection flow, production flow and circulation days were inputted as past circulation test data, to discuss the characteristics of geological layers, especially the permeability data, by which the features of temperature profiles in each well can be explained. As a result, it was found that the extension of permeable zone affecting the temperature in the SKG-2 well equivalent to the shallow reservoir was larger than that in the HDR-1 well. It was also found that there was a large difference in the permeability between the HDR-2a and HDR-3 wells. 5 refs., 8 figs., 2 tabs.

  20. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

    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.

  1. Study of a wave power generator system using an air turbine having improved J-shaped blades; Kairyo J gatayoku kuki turbine wo mochiita haryoku hatsuden sochi no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Honma, T.; Omata, K.; Kojima, N. [Meiji University, Tokyo (Japan)

    1997-11-25

    An improved J-shaped blade, in which a J-shaped blade is combined with a small-size Savonius blade, has been developed, to further improve efficiency of an air turbine for wave power generator systems. A prototype model of stationary wave power generator has been developed using the improved blade, to confirm its power generation characteristics by tests in a water tank and small-scale ocean tests. The results are compared with the characteristics of the units with conventional blades. The air turbine unit with the improved blade shows an efficiency of 13 to 35%, which is higher by 10 to 20% than that of the turbine with a J-shaped blade and by 20 to 70% than that of the one with a Savonius blade, more noted at low speed of rotation. It is therefore considered that the turbine with the improved blade is suited for sea areas having a relatively low wave height. It is also considered that efficiency can be further enhanced, when one or more guide vanes are provided around the blade. 2 refs., 12 figs.

  2. Development of reverse osmosis seawater desalination system utilizing static pressure of deep sea and employing spiral-type membrane module; Supairarugata maku mojuru wo mochiita shinkai seiatsuto riyo gyakushintoho kaisui tansuika shisutemu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Noda, H. [Hachinohe Inst. of Tech., Aomori (Japan). Dept. of Mechanical Engineering; Tagawa, K.; TOkunaga, Y.; Miyatake, O. [Kyushu Univ., Fukuoka (Japan). Dept. of Chemical Systems and Engineering; Sasaki, M. [Kyushu Univ., Fukuoka (Japan). Dept. of Chemical Systems and Engineering; Ebara Corp., Tokyo (Japan)

    1999-09-10

    The reverse osmosis (RO) technique employed in desalination systems requires the pumping up of seawater above its osmosis pressure mechanically. Development of a desalination system utilizing the high static pressure of the deep sea is investigated. Experiments of seawater desalination were carried out in the East-China-sea using a device in which a spiral-type RO membrane module was installed. It is proven that fresh drinking water can be obtained from seawater utilizing the static pressure of the deep sea, without the use of electric power. A numerical analysis was conducted to predict the amount of fresh water produced. Analytical results show sufficient agreement with experimental results. (author)

  3. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-02-20

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  5. Comparison of the toxicity of wastewater disinfected with the alternatives to chlorination by bioassay using seaweed (Porphyra yezoensis conchospores); Kaiso (susabinori gai hoshi) wo mochiita seibutsu kentei ni yoru toshi gesui no enso daitai shodoku shorisui no dokusei hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Takami, T.; Maruyama, T.; Suzuki, Y. [Miyazaki University, Miyazaki (Japan). Faculty of Engineering; Kaiga, N. [Toshiba Corp., Tokyo (Japan); Miura, A. [Aomori University, Aomori (Japan). Faculty of Engineering

    1998-11-10

    The technique now in use for disinfecting municipal sewerage is the free chlorine method, and the free chlorine reacts with ammonia in the treated water for the formation of NH4Cl. The resultant compound is strongly toxic and harms aquatic organisms, this creating a knotty problem to solve. In this report, a bioassay utilizing Porphyra yezoensis conchospores is performed, and the toxicity reducing effect is discussed of the seaweed on water specimens disinfected by free chlorine, chlorine dioxide, ozone, and ultraviolet rays. Porphyra yezoensis is easy to acquire, and the bioassay evaluates the toxicity of the water specimens by evaluating the survival rate of conchospores discharged by free-living conchoceles and the rate of inhibited sprouting. The outcome is summarized below. The injection dose required for inactivating 99.9% of the groups of coli bacteria in the treated water and the trend of fluctuations in the concentration level are obtained. No inhibition of conchospore sprouting occurs even with the addition of 100% of treated water in the chlorine-disinfected specimen or chlorine dioxide-disinfected specimen. 19 refs., 8 figs., 2 tabs.

  6. Morphological and structural modulation of PbWO{sub 4} crystals directed by dextrans

    Energy Technology Data Exchange (ETDEWEB)

    Yang Jinhu; Lu Conghua; Su Hong; Ma Jiming; Cheng Humin; Qi Limin [Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Stable and Unstable Species, College of Chemistry, Peking University, Beijing 100871 (China)

    2008-01-23

    A facile, dextran-directed solution route for the morphology- and structure-controlled synthesis of PbWO{sub 4} crystals, such as monoclinic raspite PbWO{sub 4} nanobelts and tetragonal stolzite PbWO{sub 4} crystals with penniform and wheat-ear-like morphologies, has been demonstrated. Three differently charged dextrans were employed for the PbWO{sub 4} crystallization and they turned out to be very effective in the morphological and structural modulation of PbWO{sub 4} crystals, as evidenced by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD) and Raman spectroscopy characterizations. In particular, novel monoclinic raspite PbWO{sub 4} nanobelts were produced under the direction of anionic dextran with a suitable concentration, probably due to the specific interactions between SO{sub 4}{sup 2-} groups from anionic dextran molecules and Pb{sup 2+} ions from PbWO{sub 4} crystals. To the best of our knowledge, this is the first synthesis of monoclinic raspite PbWO{sub 4} in the laboratory, which usually exists as a natural crystal. In addition, the photoluminescence properties of the obtained PbWO{sub 4} crystals with different morphologies and crystal structures have been characterized and discussed, which provides useful information for the fundamental investigation and potential application of PbWO{sub 4} crystals.

  7. Acetone sensing of multi-networked WO3-NiO core-shell nanorod sensors

    Science.gov (United States)

    Choi, Seungbok; Lee, Jae Kyung; Lee, Woo Seok; Lee, Chongmu; Lee, Wan In

    2017-10-01

    WO3-NiO core-shell nanorods were synthesized by thermal evaporation of a mixture of WO3 and graphite powders and immersion of the synthesized WO3 nanorods in an 20 mM of nickel(II) acetate tetrahydrate (Ni(OCOCH3)2·4H2O) solution followed by UV irradiation and annealing. Subsequently, multi-networked nanorod sensors were fabricated by connecting these nanostructures with electrodes. The sensing properties of pristine WO3 nanorod and WO3-NiO core-shell nanorod sensors toward acetone were examined. Subsequently, multi-networked nanorod sensors were fabricated by connecting these nanostructures with electrodes. The WO3-NiO core-shell nanorod sensor exhibited a stronger response to acetone gas and shorter response/recovery times than the pristine WO3 nanorod sensor. The pristine WO3 nanorods showed responses of approximately 1.36 to 200 ppm of CH3COCH3 at 300 °C. On the other hand, the WO3-NiO core-shell nanorods showed responses of 4.4 to the same concentration of CH3COCH3 at the same temperature. The core-shell nanorods exhibited response and recovery times of 51 s and 59 s, respectively for 200 ppm of CH3COCH3. On the other hand, the pristine WO3 nanorods exhibited response and recovery times of 51 s and 59 s, respectively, for the same concentration of CH3COCH3. NiO coating enhanced the selectivity of the WO3 nanorods for acetone as well as the sensitivity of the WO3 nanorods. The underlying mechanism of the enhanced response of the WO3-NiO core-shell nanorod sensor is also discussed in detail.

  8. Chemical purification of CaCO{sub 3} and CaWO{sub 4} powders used for CaWO{sub 4} crystal production for the CRESST experiment

    Energy Technology Data Exchange (ETDEWEB)

    Trinh Thi, H.H.; Defay, X.; Erb, A.; Hampf, R.; Lanfranchi, J.C.; Langenkaemper, A.; Morgalyuk, V.; Muenster, A.; Mondragon, E.; Oppenheimer, C.; Potzel, W.; Schoenert, S.; Steiger, H.; Ulrich, A.; Wawoczny, S.; Willers, M.; Zoeller, A. [Physik-Department and Excellence Cluster Universe, Technische Universitaet Muenchen, Garching (Germany)

    2016-07-01

    CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) uses CaWO{sub 4} single crystals as targets for the direct search for dark matter particles. Since several years these CaWO{sub 4} crystals are grown at the Technische Universitaet Muenchen. Thereby, commercially available CaCO{sub 3} and WO{sub 3} powders are used for the synthesis of CaWO{sub 4} powder. For the experiment low intrinsic contaminations of the crystals play a crucial role. In order to improve the radiopurity of the crystals it is necessary to reduce potential sources for radioactive backgrounds such as U and Th. In this poster we will present our studies of the chemical purification of the CaCO{sub 3} and CaWO{sub 4} powders.

  9. Preparation and characterization of WO{sub 3} nanoparticles, WO{sub 3}/TiO{sub 2} core/shell nanocomposites and PEDOT:PSS/WO{sub 3} composite thin films for photocatalytic and electrochromic applications

    Energy Technology Data Exchange (ETDEWEB)

    Boyadjiev, Stefan I., E-mail: boiajiev@gmail.com [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Santos, Gustavo dos Lopes; Szűcs, Júlia [Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Szilágyi, Imre M., E-mail: imre.szilagyi@mail.bme.hu [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Szent Gellért tér 4, Budapest, H-1111 (Hungary)

    2016-03-25

    In this study, monoclinic WO{sub 3} nanoparticles were obtained by thermal decomposition of (NH{sub 4}){sub x}WO{sub 3} in air at 600 °C. On them by atomic layer deposition (ALD) TiO{sub 2} films were deposited, and thus core/shell WO{sub 3}/TiO{sub 2} nanocomposites were prepared. We prepared composites of WO{sub 3} nanoparticles with conductive polymer as PEDOT:PSS, and deposited thin films of them on glass and ITO substrates by spin coating. The formation, morphology, composition and structure of the as-prepared pure and composite nanoparticles, as well thin films, were studied by TEM, SEM-EDX and XRD. The photocatalytic activity of both the WO{sub 3} and core/shell WO{sub 3}/TiO{sub 2} nanoparticles was studied by decomposing methyl orange in aqueous solution under UV light irradiation. Cyclic voltammetry measurements were performed on the composite PEDOT:PSS/WO{sub 3} thin films, and the coloring and bleaching states were studied.

  10. Poly(methacrylic acid)-mediated morphosynthesis of PbWO4 micro-crystals

    International Nuclear Information System (INIS)

    Yu, J.G.; Zhao, X.F.; Liu, S.W.; Li, M.; Mann, S.; Ng, D.H.L.

    2007-01-01

    PbWO 4 crystals with various morphologies were fabricated via a facile poly(methacrylic acid)-mediated hydrothermal route. Novel microsized PbWO 4 single crystals with a needle-like shape as well as other morphologies, such as a fishbone, dendrite, sphere, spindle, ellipsoid, rod, and dumbbell with two dandelion-like heads, could be produced. The presence of PMAA, [Pb 2+ ]/[WO 4 2- ] molar ratio (R), and aging temperature played key roles in the formation of the PbWO 4 needle-like structures. Between temperatures of 60 to 150 C, the length and photoluminescence intensities of the PbWO 4 micro needles significantly increased with aging temperature, while the diameter did not change remarkably. Time-dependent experiments revealed that the formation of PbWO 4 microneedles involved an unusual growth process, involving nucleation, oriented assembly and controlled mesoscale restructuring of nanoparticle building blocks. (orig.)

  11. NixWO2.72 nanorods as an efficient electrocatalyst for oxygen evolution reaction

    OpenAIRE

    Zheng Xi; Adriana Mendoza-Garcia; Huiyuan Zhu; MiaoFang Chi; Dong Su; Daniel P. Erdosy; Junrui Li; Shouheng Sun

    2017-01-01

    NixWO2.72 nanorods (NRs) are synthesized by a one-pot reaction of Ni(acac)2 and WCl4. In the rod structure, Ni(II) intercalates in the defective perovskite-type WO2.72 and is stabilized. The NixWO2.72 NRs show the x-dependent electrocatalysis for the oxygen evolution reaction (OER) in 0.1 M KOH with Ni0.78WO2.72 being the most efficient, even outperforming the commercial Ir-catalyst. The synthesis is not limited to NixWO2.72 but can be extended to MxWO2.72 (M = Co, Fe) as well, providing a ne...

  12. Photocatalytic Removal of Microcystin-LR by Advanced WO3-Based Nanoparticles under Simulated Solar Light

    Science.gov (United States)

    Zhao, Chao; Li, Dawei; Feng, Chuanping; Zhang, Zhenya; Sugiura, Norio; Yang, Yingnan

    2015-01-01

    A series of advanced WO3-based photocatalysts including CuO/WO3, Pd/WO3, and Pt/WO3 were synthesized for the photocatalytic removal of microcystin-LR (MC-LR) under simulated solar light. In the present study, Pt/WO3 exhibited the best performance for the photocatalytic degradation of MC-LR. The MC-LR degradation can be described by pseudo-first-order kinetic model. Chloride ion (Cl−) with proper concentration could enhance the MC-LR degradation. The presence of metal cations (Cu2+ and Fe3+) improved the photocatalytic degradation of MC-LR. This study suggests that Pt/WO3 photocatalytic oxidation under solar light is a promising option for the purification of water containing MC-LR. PMID:25884038

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

    Science.gov (United States)

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

    2017-05-01

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

  14. HRTEM Microstructural Characterization of β-WO3 Thin Films Deposited by Reactive RF Magnetron Sputtering.

    Science.gov (United States)

    Faudoa-Arzate, A; Arteaga-Durán, A; Saenz-Hernández, R J; Botello-Zubiate, M E; Realyvazquez-Guevara, P R; Matutes-Aquino, J A

    2017-02-17

    Though tungsten trioxide (WO3) in bulk, nanosphere, and thin film samples has been extensively studied, few studies have been dedicated to the crystallographic structure of WO3 thin films. In this work, the evolution from amorphous WO3 thin films to crystalline WO3 thin films is discussed. WO3 thin films were fabricated on silicon substrates (Si/SiO2) by RF reactive magnetron sputtering. Once a thin film was deposited, two successive annealing treatments were made: an initial annealing at 400 °C for 6 h was followed by a second annealing at 350 °C for 1 h. Film characterization was carried out by X-ray diffraction (XRD), high-resolution electron transmission microscopy (HRTEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques. The β-WO3 final phase grew in form of columnar crystals and its growth plane was determined by HRTEM.

  15. HRTEM Microstructural Characterization of β-WO3 Thin Films Deposited by Reactive RF Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    A. Faudoa-Arzate

    2017-02-01

    Full Text Available Though tungsten trioxide (WO3 in bulk, nanosphere, and thin film samples has been extensively studied, few studies have been dedicated to the crystallographic structure of WO3 thin films. In this work, the evolution from amorphous WO3 thin films to crystalline WO3 thin films is discussed. WO3 thin films were fabricated on silicon substrates (Si/SiO2 by RF reactive magnetron sputtering. Once a thin film was deposited, two successive annealing treatments were made: an initial annealing at 400 °C for 6 h was followed by a second annealing at 350 °C for 1 h. Film characterization was carried out by X-ray diffraction (XRD, high-resolution electron transmission microscopy (HRTEM, scanning electron microscopy (SEM, and atomic force microscopy (AFM techniques. The β-WO3 final phase grew in form of columnar crystals and its growth plane was determined by HRTEM.

  16. Preparation of WO3 Nanoparticles Using Cetyl Trimethyl Ammonium Bromide Supermolecular Template

    OpenAIRE

    Nilofar Asim; S. Radiman; M. A.B. Yarmo

    2009-01-01

    Problem statement: WO3 is one of the most interested metal oxides because of its application as catalysts, sensors, electrochromic devices, ceramic, solar cell, pigments and so on. More investigation is needed to find the good and low cost method for preparation of WO3 nanoparticles with uniform morphology and narrow distribution using a surfactant mediated method. Approach: In this study, the synthesis of WO3 nanoparticles was accomplished using a cationic surfactant (cetyl trimethyl ammoniu...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-05

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-08-15

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

  19. CTAB-assisted ultrasonic synthesis, characterization and photocatalytic properties of WO3

    International Nuclear Information System (INIS)

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

    2015-01-01

    Highlights: • WO 3 2D nanostructures were synthesized by ultrasound method assisted with CTAB. • WO 3 morphology was mainly of rectangular nanoplates with a thickness of ∼50 nm. • The highest surface area value of WO 3 was obtained to lowest concentration of CTAB. • WO 3 activity was attributed to morphology, surface area and the addition of CTAB. • WO 3 nanoplates were able to causing almost complete mineralization of rhB and IC. - Abstract: WO 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 3 was confirmed by X-ray powder diffraction (XRD). The characterization of the WO 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 g ) of the WO 3 samples. The photocatalytic activity of the WO 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 3 . Photodegradation of rhB and IC were followed by means of UV–vis absorption spectra. The mineralization degree of organic dyes by WO 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

  20. Acoustic properties of monocrystals Na Bi(WO4)2

    International Nuclear Information System (INIS)

    Khusravbekov, L.; Rakhimov, I.K.; Salakhutdinov, M.I.; Kholov, A.

    2001-01-01

    Present article is devoted to acoustic properties of monocrystals Na Bi(WO 4 ) 2 . The method of growing of large, homogeneous, defect-free monocrystals of Na Bi(WO 4 ) 2 compound was elaborated. The measurement of propagation velocity and ultrasound absorption coefficient in Na Bi(WO 4 ) 2 at temperature range 30-100 deg C on operating frequency 35 MHz was conducted by means of phase-interference method.

  1. Progress in PbWO4 scintillating crystal

    International Nuclear Information System (INIS)

    Fyodorov, A.; Korzhik, M.; Missevitch, O.; Pavlenko, V.; Kachanov, V.; Singovsky, A.; Annenkov, A.N.; Ligun, V.A.; Peigneux, J.P.; Vialle, J.P.

    1994-12-01

    Lead tungstate PbWO 4 (PWO) has recently been shown to be a promising scintillating material for precise electromagnetic calorimetry. Modifications of PWO technology were made to improve the uniformity of the crystal properties. A model of the scintillation mechanism for PWO was developed and served to guide the improvement. The complex spectroscopic analysis of the crystal after improvement is presented, as well as the new crystal properties achieved. (K.A.). 14 refs., 14 figs., 4 tabs

  2. Phase diagram of NaFe(WO{sub 4}){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Yvonne; Orbe, Stephanie; Heyer, Oliver; Lorenz, Thomas [II. Physikalisches Institut, University of Cologne (Germany); Jodlauk, Sven; Albiez, Sebastian; Becker, Petra; Bohaty, Ladislav [Institut fuer Kristallographie, University of Cologne (Germany)

    2011-07-01

    Multiferroic materials show simultaneous ferroelectric and magnetic order, which are strongly coupled to each other. A well-known model system is MnWO{sub 4} with only one kind of magnetic ions and three magnetically ordered phases below {proportional_to}13 K. Here, the multiferroic behavior of one of these phases arises from an incommensurate spin spiral structure. Much less is known about the double tungstate NaFe(WO{sub 4}){sub 2}, which has a structure closely related to MnWO{sub 4}. While in MnWO{sub 4} sheets parallel (100) of MnO{sub 6} zig-zag chains alternate with similar sheets of WO{sub 6}, in NaFe(WO{sub 4}){sub 2} an alternating sheet sequence FeO{sub 6}-WO{sub 6}-NaO{sub 6}-WO{sub 6} - is found. Consequently, the a lattice parameter is doubled and the magnetic subsystem is diluted. The ordering temperature in NaFe(WO{sub 4}){sub 2} is reduced to T{sub N}{approx} 4 K. The magnetic structure in zero magnetic field is reported to be collinear antiferromagnetic, but the H-T phase diagram has not been published so far. Here, we present a detailed study of this phase diagram obtained by high-resolution thermal expansion and magnetostriction measurements. We find pronounced hysteresis effects, which resemble those observed in other multiferroic materials.

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

    Directory of Open Access Journals (Sweden)

    Tatsuya Ida

    2014-09-01

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

  4. Preparation of WO3 thin film by successive dip coating for electrochromic and photoelectrochromic devices

    International Nuclear Information System (INIS)

    Park, Jae Hyuk; Kang, Jin Soo; Kim, Jin; Lee, Kyung Jae; Sung, Yung Eun; Cha, In Young

    2015-01-01

    Here we report the superiority of WO 3 thin films prepared by successive dip coating in electrochromic devices. Dip coatings were done on transparent conducting oxide substrates in the WO 3 precursor solution a number of times without drying in between the coating steps. This process enabled the fabrication of WO 3 films with optimum thickness and large roughness, which led to enhanced performance when they were employed as the electrode in electrochromic devices. We made a further observation by applying these electrodes in photoelectrochromic devices and verified the excellent properties of the successively dip-coated WO 3 films

  5. Phase relations and chemical vapor transport of hexagonal indium tungsten bronze InxWO3

    International Nuclear Information System (INIS)

    Steiner, Udo

    2014-01-01

    Highlights: • Phase relations of hexagonal bronze In x WO 3 with neighboring phases. • Chemical vapor transport experiments using NH 4 Cl as transport agent. • Single crystals of In x WO 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 x WO 3 (x = 0.25–0.35) were synthesized by solid state reaction at 1173 K. The phase relations of In x WO 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 4 X (X = Cl, Br, I) as transport agent. Crystals of hexagonal indium tungsten bronze were deposited beside In 2 W 3 O 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 x WO 3 /In 2 W 3 O 12 /In 0.02 WO 3 . Sole deposition of In x WO 3 single crystals with composition x ≈ 0.33 was observed from ternary mixtures In x WO 3 /W 18 O 49 /WO 2 with a migration rate of about 0.5 mg/h (transport agent NH 4 Cl)

  6. Tungsten oxides. I. Effects of oxygen vacancies and doping on electronic and optical properties of different phases of WO3

    Science.gov (United States)

    Migas, D. B.; Shaposhnikov, V. L.; Rodin, V. N.; Borisenko, V. E.

    2010-11-01

    In this part we present results of our ab initio calculations indicating that dispersion of the bands near the gap region for different phases of WO3 (namely, ɛ-WO3, δ-WO3, γ-WO3, β-WO3, orth-WO3, α-WO3, and hex-WO3) is rather close. The rapid increase in the absorption coefficient starts at the lower energy range for α-WO3 and hex-WO3 than for the other phases in accordance with the calculated band gaps. An oxygen vacancy has turned out to decrease the gap by 0.50 eV and to shift the absorption coefficient to the lower energy range in the room temperature γ-WO3 phase. We have also traced changes caused by molybdenum and sulfur doping of γ-WO3. Only sulfur doped γ-WO3 has been revealed to display the formation of the impurity band along with a sizable reduction in the gap and the shift in the absorption coefficient to the lower energy range.

  7. CONTINUOUS-WAVE MICROCHIP LASER GENERATION OF Tm:KLu(WO42 AND Tm:KY(WO42 CRYSTALS

    Directory of Open Access Journals (Sweden)

    O. P. Dernovich

    2016-01-01

    Full Text Available Diode-pumped solid-state lasers are attractive for a variety of practical applications in many fields of human activity due to their high efficiency, compactness, and long durability. For applications in remote sensing lasers emitting in the spectral range of about 2 microns are required. Materials doped with trivalent thulium ions are promising active media emitting in this spectral range. Potassium rare-earth tungstates are attractive materials among Tm-doped crystals due to their suitable characteristics, such as high values of absorption and stimulated emission cross sections, incignificant concentration quenching of luminescence, well-proven technology of the high quality crystals growth. The purpose of this paper was to compare lasing properties of lasers based on potassium lutetium and potassium yttrium tungstate crystals doped with thulium ions in continuous-wave regime. Experiments were carried out with a diode pumping in microchip cavity configuration. The maximum power of laser radiation at 1947 nm of 1010 mW was obtained with Tm:KY(WO42 crystal with the slope efficiency with respect to the absorbed pump power of 51 %. When Tm:KLu(WO42 crystal was utilized an output power of 910 mW at 1968 nm wavelength with the slope efficiency of 38 % was obtained. With Tm:KLu(WO42 laser a tuning range over 160 nm range was realized with a prism inserted into the laser cavity. 

  8. Preparation and emission properties of NaBi(WO4)2 and NaBi(WO4)2:Ce single crystals

    International Nuclear Information System (INIS)

    Nitsch, K.; Nikl, M.; Barta, C.; Triska, A.

    1990-01-01

    The preparation of pure and Ce 3+ -doped NaBi(WO 4 ) 2 single crystals (NBW) and the determination of their basic transmission and emission properties including time-resolved measurements are described. The decay of NBW emission is obviously non-exponential. It can be concluded that emission arises at regular sites of the crystal lattice and is connected with electronic transitions from Bi 3+ to the WO 4 2- group and/or excitation of the WO 4 2- group itself. It is not possible to excite Ce 3+ ions directly

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-30

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

  10. WoPeD - A "Proof-of-Concept" Platform for Experimental BPM Research Projects

    DEFF Research Database (Denmark)

    Freytag, Thomas; Allgaier, Philip; Burattin, Andrea

    2017-01-01

    WoPeD (Workflow Petrinet Designer) is an open-source, Java-based software product supporting the creation, simulation and analysis of business process models. Over the years, WoPeD has become a widely-used tool in the academic sector, primarily known and used for teaching purposes. To some extent...

  11. Facile synthesis of layered MnWO{sub 4}/reduced graphene oxide for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jianhua; Shen, Jianfeng, E-mail: jfshen@fudan.edu.cn; Li, Na; Ye, Mingxin, E-mail: mxye@fudan.edu.cn

    2016-05-05

    The layered MnWO{sub 4}/reduced graphene oxide (MnWO{sub 4}/RGO) was prepared through a facile one-pot low-temperature hydrothermal route without using any templates. The structure and morphology of MnWO{sub 4}/RGO nanocomposite were characterized through X-ray diffraction, Raman spectra, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption/desorption and thermo-gravimetric analysis. While its electrochemical behaviors were investigated using cyclic voltammograms, galvanostatic charge/discharge and electrochemical impedance spectroscopy. In the case of three electrode cells, MnWO{sub 4}/RGO with 7.28 wt% RGO content fulfilled a maximum specific capacitance of 288 F g{sup −1} at 5 mV s{sup −1} with the potential range from −0.35–0.55 V. While in the two electrode cell, it obtained a maximum specific capacitance of 109 F g{sup −1} at 5 mV s{sup −1} and displayed the cycle life of 14.9% capacitance decline after 6000 cycles. - Highlights: • The MnWO{sub 4}/RGO was first prepared through a facile hydrothermal route. • MnWO{sub 4}/RGO composite show much higher specific capacitances than pure MnWO{sub 4}. • The electrochemical properties of MnWO{sub 4}/RGO arise from the synergistic effect.

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

    Indian Academy of Sciences (India)

    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 ...

  13. Optical properties of WO{sub 3} thin films using surface plasmon resonance technique

    Energy Technology Data Exchange (ETDEWEB)

    Paliwal, Ayushi; Sharma, Anjali; Gupta, Vinay, E-mail: drguptavinay@gmail.com, E-mail: vgupta@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Tomar, Monika [Department of Physics, Miranda House, University of Delhi, Delhi 110007 (India)

    2014-01-28

    Indigenously assembled surface plasmon resonance (SPR) technique has been exploited to study the thickness dependent dielectric properties of WO{sub 3} thin films. WO{sub 3} thin films (80 nm to 200 nm) have been deposited onto gold (Au) coated glass prism by sputtering technique. The structural, optical properties and surface morphology of the deposited WO{sub 3} thin films were studied using X-ray diffraction, UV-visible spectrophotometer, Raman spectroscopy, and Scanning electron microscopy (SEM). XRD analysis shows that all the deposited WO{sub 3} thin films are exhibiting preferred (020) orientation and Raman data indicates that the films possess single phase monoclinic structure. SEM images reveal the variation in grain size with increase in thickness. The SPR reflectance curves of the WO{sub 3}/Au/prism structure were utilized to estimate the dielectric properties of WO{sub 3} thin films at optical frequency (λ = 633 nm). As the thickness of WO{sub 3} thin film increases from 80 nm to 200 nm, the dielectric constant is seen to be decreasing from 5.76 to 3.42, while the dielectric loss reduces from 0.098 to 0.01. The estimated value of refractive index of WO{sub 3} film is in agreement to that obtained from UV-visible spectroscopy studies. The strong dispersion in refractive index is observed with wavelength of incident laser light.

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

    NARCIS (Netherlands)

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

    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

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    Indian Academy of Sciences (India)

    TECS

    Abstract. 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 pro-.

  17. Electrical and optical properties of ZnO–WO3 nanocomposite and its ...

    Indian Academy of Sciences (India)

    Abstract. This study reports the humidity sensing characteristics of ZnO–WO3 nanocomposite. Pellet samples of. 0–5 weight% ZnO in WO3 were sintered from 300 to 600◦C. When exposed to humidity, the resistance of the sensing samples was found to decrease with increase in relative humidity (RH). Five percent ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-06-05

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

  19. Physical properties characterization of WO3 films grown by hot-filament metal oxide deposition

    International Nuclear Information System (INIS)

    Diaz-Reyes, J.; Delgado-Macuil, R.J.; Dorantes-Garcia, V.; Perez-Benitez, A.; Balderas-Lopez, J.A.; Ariza-Ortega, J.A.

    2010-01-01

    WO 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 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 3 presents broad peaks in the range of 1100 to 3600 cm -1 . A broad band in the 2200 to 3600 cm -1 region and the peaks sited at 1645 and 1432 cm -1 are well resolved, which are originated from moisture and are assigned to ν(OH) and δ(OH) modes of adsorbed water and the corresponding tungsten oxide vibrations are in infrared region from 400 to 1453 cm -1 and around 3492 cm -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 -1 that are typical Raman peaks of crystalline WO 3 (m-phase) that correspond to stretching vibrations of the bridging oxygen, which are assigned to W-O stretching (ν) and W-O bending (δ) modes, respectively. By transmittance measurements obtains that the WO 3 band gap can be varied from 2.92 to 3.13 eV in the investigated annealing temperature range.

  20. Tribological Behaviour of OA-Capped WO3 Nanoparticles as an Additive to Base Oils

    International Nuclear Information System (INIS)

    Siti Fazlili Abdullah

    2008-01-01

    Oleic acid (OA) capped wolfram (VI) oxide, WO 3 nanoparticles were chemically synthesized and characterized by means of Fourier Transform-Infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The tribological properties of the capped WO 3 nanoparticles as an additive in base oils were investigated using a four-ball machine. Results show that OA-capped WO 3 nanoparticles are able to prevent water adsorption and capable of being dispersed stable in organic solvents which is base oils. The as-prepared capped WO 3 nanoparticles have an average size of 15 nm. In addition, OA-capped WO 3 nanoparticles as an additive in base oils perform good anti-wear (AW) and anti-friction (AF) properties owing to the formation of a boundary film. (author)

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

    Science.gov (United States)

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

    2017-01-01

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

  2. The enhanced alcohol-sensing response of ultrathin WO3 nanoplates

    International Nuclear Information System (INIS)

    Chen Deliang; Hou Xianxiang; Wen Hejing; Wang Yu; Wang Hailong; Zhang Rui; Lu Hongxia; Xu Hongliang; Guan Shaokang; Li Xinjian; Sun Jing; Gao Lian

    2010-01-01

    Chemical sensors based on semiconducting metal oxide nanocrystals are of academic and practical significance in industrial processing and environment-related applications. Novel alcohol response sensors using two-dimensional WO 3 nanoplates as active elements have been investigated in this paper. Single-crystalline WO 3 nanoplates were synthesized through a topochemical approach on the basis of intercalation chemistry (Chen et al 2008 Small 4 1813). The as-obtained WO 3 nanoplate pastes were coated on the surface of an Al 2 O 3 ceramic microtube with four Pt electrodes to measure their alcohol-sensing properties. The results show that the WO 3 nanoplate sensors are highly sensitive to alcohols (e.g., methanol, ethanol, isopropanol and butanol) at moderate operating temperatures (260-360 deg. C). For butanol, the WO 3 nanoplate sensors have a sensitivity of 31 at 2 ppm and 161 at 100 ppm, operating at 300 deg. C. For other alcohols, WO 3 nanoplate sensors also show high sensitivities: 33 for methanol at 300 ppm, 70 for ethanol at 200 ppm, and 75 for isopropanol at 200 ppm. The response and recovery times of the WO 3 nanoplate sensors are less than 15 s for all the test alcohols. A good linear relationship between the sensitivity and alcohol concentrations has been observed in the range of 2-300 ppm, whereas the WO 3 nanoparticle sensors have not shown such a linear relationship. The sensitivities of the WO 3 nanoplate sensors decrease and their response times become short when the operating temperatures increase. The enhanced alcohol-sensing performance could be attributed to the ultrathin platelike morphology, the high crystallinity and the loosely assembling structure of the WO 3 nanoplates, due to the advantages of the effective adsorption and rapid diffusion of the alcohol molecules.

  3. The enhanced alcohol-sensing response of ultrathin WO3 nanoplates

    Science.gov (United States)

    Chen, Deliang; Hou, Xianxiang; Wen, Hejing; Wang, Yu; Wang, Hailong; Li, Xinjian; Zhang, Rui; Lu, Hongxia; Xu, Hongliang; Guan, Shaokang; Sun, Jing; Gao, Lian

    2010-01-01

    Chemical sensors based on semiconducting metal oxide nanocrystals are of academic and practical significance in industrial processing and environment-related applications. Novel alcohol response sensors using two-dimensional WO3 nanoplates as active elements have been investigated in this paper. Single-crystalline WO3 nanoplates were synthesized through a topochemical approach on the basis of intercalation chemistry (Chen et al 2008 Small 4 1813). The as-obtained WO3 nanoplate pastes were coated on the surface of an Al2O3 ceramic microtube with four Pt electrodes to measure their alcohol-sensing properties. The results show that the WO3 nanoplate sensors are highly sensitive to alcohols (e.g., methanol, ethanol, isopropanol and butanol) at moderate operating temperatures (260-360 °C). For butanol, the WO3 nanoplate sensors have a sensitivity of 31 at 2 ppm and 161 at 100 ppm, operating at 300 °C. For other alcohols, WO3 nanoplate sensors also show high sensitivities: 33 for methanol at 300 ppm, 70 for ethanol at 200 ppm, and 75 for isopropanol at 200 ppm. The response and recovery times of the WO3 nanoplate sensors are less than 15 s for all the test alcohols. A good linear relationship between the sensitivity and alcohol concentrations has been observed in the range of 2-300 ppm, whereas the WO3 nanoparticle sensors have not shown such a linear relationship. The sensitivities of the WO3 nanoplate sensors decrease and their response times become short when the operating temperatures increase. The enhanced alcohol-sensing performance could be attributed to the ultrathin platelike morphology, the high crystallinity and the loosely assembling structure of the WO3 nanoplates, due to the advantages of the effective adsorption and rapid diffusion of the alcohol molecules.

  4. Photoactivity and stability of Ag2WO4 for organic degradation in aqueous suspensions

    International Nuclear Information System (INIS)

    Chen, Haihang; Xu, Yiming

    2014-01-01

    Graphical abstract: Both α- and β-Ag 2 WO 4 are photoactive for organic degradation in aqueous solutions, and β-Ag 2 WO 4 is more active than α-Ag 2 WO 4 under UV light, but both the catalysts are not stable against photodecomposition to form metallic silver particles. - Highlights: • Two catalysts are photoactive, but not stable for organic degradation in water under UV light. • Comparatively, β-Ag 2 WO 4 is more photoactive but less stable than α-Ag 2 WO 4 . • Metallic silver particles are formed during organic degradation under UV light. - Abstract: Silver tungstate as photocatalyst for water splitting and dye degradation has been reported, but the catalyst stability is not known. In this work, we find that both α- and β-Ag 2 WO 4 are not stable under UV light for the photocatalytic degradation of phenol and azo-dye X3B in aqueous solutions. Comparatively, β-Ag 2 WO 4 was more photoactive, but less stable than α-Ag 2 WO 4 . Solid characterization with X-ray diffraction and scanning electron microscope showed that metallic silver particles were produced with the two catalysts, consequently resulting into decrease in the activity for organic degradation. Measurement of photoluminescence revealed that β-Ag 2 WO 4 had a weaker band gap emission and higher portion of structural defects than α-Ag 2 WO 4 . A possible mechanism responsible for the observed difference in photoactivity and stability between the two tungstates is proposed

  5. The enhanced alcohol-sensing response of ultrathin WO{sub 3} nanoplates

    Energy Technology Data Exchange (ETDEWEB)

    Chen Deliang; Hou Xianxiang; Wen Hejing; Wang Yu; Wang Hailong; Zhang Rui; Lu Hongxia; Xu Hongliang; Guan Shaokang [School of Materials Science and Engineering, Zhengzhou University, 100 Science Road, Zhengzhou 450001 (China); Li Xinjian [School of Physics and Engineering, Zhengzhou University, 100 Science Road, Zhengzhou 450001 (China); Sun Jing; Gao Lian, E-mail: dlchen@zzu.edu.cn, E-mail: dlchennano@hotmail.com [The State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2010-01-22

    Chemical sensors based on semiconducting metal oxide nanocrystals are of academic and practical significance in industrial processing and environment-related applications. Novel alcohol response sensors using two-dimensional WO{sub 3} nanoplates as active elements have been investigated in this paper. Single-crystalline WO{sub 3} nanoplates were synthesized through a topochemical approach on the basis of intercalation chemistry (Chen et al 2008 Small 4 1813). The as-obtained WO{sub 3} nanoplate pastes were coated on the surface of an Al{sub 2}O{sub 3} ceramic microtube with four Pt electrodes to measure their alcohol-sensing properties. The results show that the WO{sub 3} nanoplate sensors are highly sensitive to alcohols (e.g., methanol, ethanol, isopropanol and butanol) at moderate operating temperatures (260-360 deg. C). For butanol, the WO{sub 3} nanoplate sensors have a sensitivity of 31 at 2 ppm and 161 at 100 ppm, operating at 300 deg. C. For other alcohols, WO{sub 3} nanoplate sensors also show high sensitivities: 33 for methanol at 300 ppm, 70 for ethanol at 200 ppm, and 75 for isopropanol at 200 ppm. The response and recovery times of the WO{sub 3} nanoplate sensors are less than 15 s for all the test alcohols. A good linear relationship between the sensitivity and alcohol concentrations has been observed in the range of 2-300 ppm, whereas the WO{sub 3} nanoparticle sensors have not shown such a linear relationship. The sensitivities of the WO{sub 3} nanoplate sensors decrease and their response times become short when the operating temperatures increase. The enhanced alcohol-sensing performance could be attributed to the ultrathin platelike morphology, the high crystallinity and the loosely assembling structure of the WO{sub 3} nanoplates, due to the advantages of the effective adsorption and rapid diffusion of the alcohol molecules.

  6. Enhancement of visible-light photocatalytic activity of silver and mesoporous carbon co-modified Bi2WO6

    International Nuclear Information System (INIS)

    Zhao, Qian; Gong, Ming; Liu, Wangping; Mao, Yulin; Le, Shukun; Ju, Shang; Long, Fei; Liu, Xiufang; Liu, Kai; Jiang, Tingshun

    2015-01-01

    Graphical abstract: - Highlights: • Silver and mesoporous carbon co-modified Bi 2 WO 6 (Ag/Bi 2 WO 6 /CMK-3) composite was prepared. • Photocatalytic activity of Bi 2 WO 6 was remarkably enhanced by co-modification of silver and mesoporous carbon. • The degradation rate of MB can reach ca. 95.1% under visible light irradiation. • The Ag/Bi 2 WO 6 /CMK-3 composite has good stability and potential application prospects. - Abstract: Ordered mesoporous carbon CMK-3 was prepared by hard template method using SBA-15 as template, sucrose as carbon source. Flower/sphere-like Bi 2 WO 6 and CMK-3/Bi 2 WO 6 photocatalysts were synthesized by hydrothermal method, and then Ag/Bi 2 WO 6 and Ag/Bi 2 WO 6 /CMK-3 composite photocatalysts were prepared via a photoreduction process. The samples were characterized by XRD, UV–vis, TEM (HR-TEM), SEM, N 2 physical adsorption and PL and their photocatalytic activities were evaluated by the photocatalytic degradation of methylene blue (MB) under visible light irradiation. The results show that both incorporating of CMK-3 and Ag loading greatly improved the photocatalytic activity of Bi 2 WO 6 , and the content of CMK-3 and silver have an impact on the photocatalytic activity of Bi 2 WO 6 . The photocatalytic activity of Ag/Bi 2 WO 6 /CMK-3 photocatalyst is superior to the activities of CMK-3/Bi 2 WO 6 and Ag/Bi 2 WO 6 under comparable conditions, and Ag/Bi 2 WO 6 /CMK-3 photocatalyst has high stability and is easy to be recycled. Also, the mechanism for the enhancement of the photocatalytic activity of CMK-3 and Ag co-modified Bi 2 WO 6 was also investigated

  7. Optical spectroscopy on multiferroic MnWO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Thomas; Hemberger, Joachim; Grueninger, Markus [2. Physikalisches Institut, Universitaet zu Koeln (Germany); Pimenov, Andrei; Shuvaev, Alexey [Experimentelle Physik 4, Universitaet Wuerzburg (Germany); Becker-Bohaty, Petra; Bohaty, Ladislav [Institut fuer Kristallographie, Universitaet zu Koeln (Germany)

    2008-07-01

    MnWO{sub 4} (Huebnerite) crystallizes in a monoclinic crystal structure composed of alternating layers of Mn{sup 2+} and W{sup 6+} ions which are octahedrally coordinated by oxygen ions. The partially frustrated spin system exhibits a negative Curie-Weiss temperature T{sub CW}{approx}-75 K in the paramagnetic regime and undergoes a sequence of transitions into complex antiferromagnetic phases below T{sub N}{approx}13.5 K, including transitions from commensurate to incommensurate and collinear to non-collinear magnetic order, which are connected to the onset or decay of ferroelectric polarization. Thus MnWO{sub 4} belongs to the class of multiferroics. We present a detailed study of the phonon modes of this compound based on polarized reflectivity measurements in the FIR and MIR regime. In addition, polarized transmission measurements in the sub-mm regime below the phonon frequencies have been carried out in order to investigate the low-energy magnetoelectric excitations, so-called electro-magnons.

  8. Combustion synthesis and characterization of nanocrystalline WO3.

    Science.gov (United States)

    Morales, Walter; Cason, Michael; Aina, Olawunmi; de Tacconi, Norma R; Rajeshwar, Krishnan

    2008-05-21

    The energy payback time associated with the semiconductor active material is an important parameter in a photovoltaic solar cell device. Thus lowering the energy requirements for the semiconductor synthesis step or making it more energy-efficient is critical toward making the overall device economics more competitive relative to other nonpolluting energy options. In this communication, combustion synthesis is demonstrated to be a versatile and energy-efficient method for preparing inorganic oxide semiconductors such as tungsten trioxide (WO3) for photovoltaic or photocatalytic solar energy conversion. The energy efficiency of combustion synthesis accrues from the fact that high process temperatures are self-sustained by the exothermicity of the combustion process, and the only external thermal energy input needed is for dehydration of the fuel/oxidizer precursor mixture and bringing it to ignition. Importantly, we show that, in this approach, it is also possible to tune the optical characteristics of the oxide semiconductor (i.e., shift its response toward the visible range of the electromagnetic spectrum) in situ by doping the host semiconductor during the formative stage itself. As a bonus, the resultant material shows enhanced surface properties such as markedly improved organic dye uptake relative to benchmark samples obtained from commercial sources. Finally, this synthesis approach requires only very simple equipment, a feature that it shares with other "mild" inorganic semiconductor synthesis routes such as sol-gel chemistry, chemical bath deposition, and electrodeposition. The present study constitutes the first use of combustion synthesis for preparing WO3 powder comprising nanosized particles.

  9. Negative thermal expansion in Sc2(WO4)3

    International Nuclear Information System (INIS)

    Evans, J.S.O.; Mary, T.A.; Sleight, A.W.

    1998-01-01

    Sc 2 (WO 4 ) 3 has been found to show the highly unusual property of negative thermal expansion over a temperature range of 10 to 1,073 K. Powder neutron diffraction data from 10 to 450 K shows an essentially linear decrease in cell volume as a function of temperature. The intrinsic linear coefficient of thermal expansion from this data is -2.2 x 10 -6 K -1 . The linear coefficient of thermal expansion measured on a ceramic bar of Sc 2 (WO 4 ) 3 can be as negative as -11 x 10 -6 K -1 due to microstructure changes as a function of temperature. Rietveld refinement as a function of temperature suggests that the intrinsic negative thermal expansion can be related to transverse vibrations of bridging oxygen atoms in the structure. The anharmonic nature of these vibrations leads to a coupled tilting of the quasi-rigid framework polyhedra. This tilting in turn causes the structure to become more dense with increasing temperature

  10. Porous three-dimensional reduced graphene oxide merged with WO3 for efficient removal of radioactive strontium

    Science.gov (United States)

    Mu, Wanjun; Yu, Qianghong; Hu, rui; Li, Xingliang; Wei, Hongyuan; Jian, Yuan

    2017-11-01

    A simple hydrothermal method was used to prepare 3D nanostructured composite adsorbents of reduced graphene oxide (RGO) and WO3 (RGO/WO3). The analysis results suggest that it possesses a mesoporous 3D structure, in which WO3 nanorods are uniformly loaded on the surface of the RGO. Combining the benefits of GO and WO3, the composites exhibit a higher adsorption capacity for removing Sr2+ from aqueous solutions over a wide pH range (4-11). Adsorption isotherms show that the data fit the Langmuir isotherms well (R > 0.99), and the maximum adsorption capacity of 149.56 mg g-1 was achieved, much higher than that for GO, WO3 and other similar adsorbents. Sr2+ adsorption on RGO/WO3 reached equilibrium within 200 min. The fast adsorption and high adsorption rate of RGO/WO3 are mostly attributable to the plentiful adsorption sites provided by the dispersed WO3 nanoparticles on the RGO surface. Furthermore, the existence of Na+ ions has no obvious effect on the removal of Sr2+ ions by RGO/WO3, and RGO/WO3 adsorbent can be repeated at least 5 times without significant loss of adsorption capacity by adsorption-desorption experiment. Thus, RGO/WO3 shows the potential ability for removal of 90Sr from radioactive wastewater.

  11. Sensing performance of palladium-functionalized WO3 nanowires by a drop-casting method

    International Nuclear Information System (INIS)

    Chávez, F.; Pérez-Sánchez, G.F.; Goiz, O.; Zaca-Morán, P.; Peña-Sierra, R.; Morales-Acevedo, A.; Felipe, C.; Soledad-Priego, M.

    2013-01-01

    In this work, we show a simple way to functionalize tungsten oxide nanowires (WO 3 -NWs) using a saturated palladium chloride (PdCl 2 ) solution deposited by a drop-casting method. WO 3 -NWs were synthesized by close-spaced chemical vapor deposition (CSVT). The morphological and structural characterizations showed that the diameters of WO 3 -NWs are in the range from 50 to 200 nm with lengths above 10 μm, and correspond to the orthorhombic phase of WO 3 , respectively. The sensor was fabricated using the WO 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 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 3 -NWs functionalized with Palladium are discussed.

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

    DEFF Research Database (Denmark)

    Grivel, J. -C.

    2012-01-01

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

  13. Structure, morphology and electrocatalytic properties of WO x thin films prepared by reactive pulsed laser deposition

    Science.gov (United States)

    Fominski, V. Y.; Grigoriev, S. N.; Romanov, R. I.; Volosova, M. A.; Fominski, D. V.; Irzhak, A. V.

    2017-12-01

    Nanostructured WO xheated substrate resulted in the formation of nanoneedles and nanosheets. Fairly good catalytic properties in hydrogen evolution reaction (HER) and in electrolytic Pt deposition were revealed for the WO x films that consisted of loosely packed ball-like nanocrystals possessing a size of ∼20 nm. The catalytic activity of the films consisted of nanoneedles and nanosheets was not good enough. Adjustable electrolytic deposition of Pt on the nanostructured WO x support film allowed to prepare effective hybrid HER catalyst containing only ∼7 μg/cm2 of Pt.

  14. Neuromorphic transistor achieved by redox reaction of WO3 thin film

    Science.gov (United States)

    Tsuchiya, Takashi; Jayabalan, Manikandan; Kawamura, Kinya; Takayanagi, Makoto; Higuchi, Tohru; Jayavel, Ramasamy; Terabe, Kazuya

    2018-04-01

    An all-solid-state neuromorphic transistor composed of a WO3 thin film and a proton-conducting electrolyte was fabricated for application to next-generation information and communication technology including artificial neural networks. The drain current exhibited a 4-order-of-magnitude increment by redox reaction of the WO3 thin film owing to proton migration. Learning and forgetting characteristics were well tuned by the gate control of WO3 redox reactions owing to the separation of the current reading path and pulse application path in the transistor structure. This technique should lead to the development of versatile and low-power-consumption neuromorphic devices.

  15. The enhanced photoactivity of nanosized Bi2WO6 catalyst for the degradation of 4-chlorophenol

    International Nuclear Information System (INIS)

    Fu Hongbo; Yao Wenqing; Zhang Liwu; Zhu Yongfa

    2008-01-01

    Nanosized Bi 2 WO 6 catalyst exhibited the enhanced photoactivity for the degradation of 4-chlorophenol (4-CP) under visible irradiation compared to the sample prepared by high-temperature solid reaction. The photoactivity of the catalyst was sensitive to pH variation of the suspension. Nanosized Bi 2 WO 6 catalyst showed the highest activity at pH 7.2. The photodegradation of 4-CP by nanosized Bi 2 WO 6 catalyst followed a pseudo-first-order reaction. After three recycling runs for the photodegradation of 4-CP, the activity of the catalyst did not show any significant loss, suggesting that the catalyst was stable under visible irradiation

  16. Magnetic properties of the strongly correlated chain antiferromagnet KTb(WO4)2

    International Nuclear Information System (INIS)

    Khatsko, E.; Loginov, A.; Cherny, A.; Rykova, A.

    2006-01-01

    The susceptibility and magnetization of a single crystal of KTb(WO 4 ) 2 has been measured in the temperature range 0.5-80 K in magnetic fields up to 6 T. It is shown that KTb(WO 4 ) 2 is an Ising magnet with only one component of the magnetic moment. The three-dimensional phase transition to the antiferromagnetically ordered state has been found below 0.7 K. This transition can be described in the molecular field two-level approximation. The principal exchange constant has been estimated. By using experimental data the magnetic structure of KTb(WO 4 ) 2 is proposed

  17. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    1996-05-01

    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.

  18. Tungsten oxide-graphene oxide (WO3-GO) nanocomposite as an efficient photocatalyst, antibacterial and anticancer agent

    Science.gov (United States)

    Jeevitha, G.; Abhinayaa, R.; Mangalaraj, D.; Ponpandian, N.

    2018-05-01

    Functioning of ultrasonically prepared tungsten oxide-graphene oxide (WO3-GO) nanocomposite as a photocatalyst, antibacterial and anticancer system was investigated and the obtained results were compared with that of pure WO3 nanoparticles. Structural, morphological, compositional and optical properties of the prepared WO3 nanoparticles and WO3-GO nanocomposite were studied. Photocatalytic efficiency of the system on organic dyes such as methylene blue (MB, cationic) and indigo carmine (IC, anionic) was investigated. The enhanced efficiency of the WO3-GO nanocomposite system was evaluated under sunlight and compared with that of pure WO3. The degradation efficiency values for MB and IC were found to be 97.03% and 95.43% at 180 and 120 min respectively. Antibacterial activity of the WO3-GO nanocomposite under visible light was tested and improved inhibition results were observed for Escherichia coli and Bacillus subtilis after 6 h of light exposure. The photocatalytic degradation efficiency and antibacterial activity of the WO3-GO nanocomposite are attributed to the improved electron-hole pair separation rate. Investigation on anticancer activity of WO3-GO nanocomposite was tested on human lung cancer (A-549) cell line and the IC50 value was found to be 139.6 ± 4.53 μg/mL. The results obtained in this study may be used as a platform for the development of photocatalysis applications based on WO3-GO nanocomposite.

  19. Experimental and theoretical investigation on photocatalytic activities of 1D Ag/Ag2WO4 nanostructures

    Science.gov (United States)

    Liu, Danqing; Huang, Weicheng; Li, Long; Liu, Lu; Sun, Xiaojun; Liu, Bo; Yang, Bin; Guo, Chongshen

    2017-09-01

    Ag2WO4 is a significant photocatalyst that responds to UV light irradiation only, which greatly hinders it for further practical application for solar light. To address this problem, herein, 1D plasmonic Ag/Ag2WO4 photocatalysts have been fabricated by a successive process including hydrothermal synthesis to obtain Ag2WO4 followed by an additional in situ chemical-reduction process for Ag decoration. Then, the structural features, optical properties, and electronic structures of Ag2WO4 and Ag/Ag2WO4 nanowires were systematically investigated via a combination of theoretical calculations and experimental evidence. The plasmon-enhanced Ag/Ag2WO4 nanowires exhibited higher visible-light-driven photocatalytic activity, which performed a desired photodestruction ratio of 91.2% on methylene blue within 60 min and good stability in five cycles. The Ag decoration greatly facilitates visible-light harvesting and thus promotes photogenerated radical oxidation to dye, which is evidenced by the higher hydroxyl radical level of Ag/Ag2WO4 detected in the ESR test during the photocatalytic process. The theoretical calculation based on density functional theory indicates that Ag nanoparticles formed on the surface of Ag2WO4 could narrow the band gap of Ag2WO4. In addition, the surface plasmon resonance absorption effect and fast charge transfer effect in the metal-semiconductor system contribute to the photocatalytic performance of Ag/Ag2WO4.

  20. Visible-light-induced WO3/g-C3N4 composites with enhanced photocatalytic activity.

    Science.gov (United States)

    Huang, Liying; Xu, Hui; Li, Yeping; Li, Huaming; Cheng, Xiaonong; Xia, Jixiang; Xu, Yuanguo; Cai, Guobin

    2013-06-28

    Novel WO3/g-C3N4 composite photocatalysts were prepared by a calcination process with different mass contents of WO3. The photocatalysts were characterized by thermogravimetric analysis (TG), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the photocatalysts was evaluated by degradation of methylene blue (MB) dye and 4-chlorophenol (4-CP) under visible light. The results indicated that the WO3/g-C3N4 composite photocatalysts showed higher photocatalytic activity than both the pure WO3 and pure g-C3N4. The optimum photocatalytic activity of WO3/g-C3N4 at a WO3 mass content of 9.7% under visible light irradiation was up to 4.2 times and 2.9 times as high as that of the pure WO3 and pure g-C3N4, respectively. The remarkably increased performance of WO3/g-C3N4 was mainly attributed to the synergistic effect between the interface of WO3 and g-C3N4, including enhanced optical absorption in the visible region, enlarged specific surface areas and the suitable band positions of WO3/g-C3N4 composites.

  1. WO3 nanorods-modified carbon electrode for sustained electron uptake from Shewanella oneidensis MR-1 with suppressed biofilm formation

    International Nuclear Information System (INIS)

    Zhang, Feng; Yuan, Shi-Jie; Li, Wen-Wei; Chen, Jie-Jie; Ko, Chi-Chiu; Yu, Han-Qing

    2015-01-01

    Highlights: • WO 3 nanorods-modified carbon paper was used as the anode of MFC. • WO 3 nanorods suppressed biofilm growth on the electrode surface. • Sustained electron transfer from cells to electrode via riboflavin was achieved. • C–WO 3 nanorods enable stable and efficient EET process in long-time operation. - Abstract: Carbon materials are widely used as electrodes for bioelectrochemical systems (BES). However, a thick biofilm tends to grow on the electrode surface during continuous operation, resulting in constrained transport of electrons and nutrients at the cell-electrode interface. In this work, we tackled this problem by adopting a WO 3 -nanorods modified carbon electrode (C–WO 3 nanorods), which completely suppressed the biofilm growth of Shewanella Oneidensis MR-1. Moreover, the C–WO 3 nanorods exhibited high electric conductivity and strong response to riboflavin. These two factors together make it possible for the C–WO 3 nanorods to maintain a sustained, efficient process of electron transfer from the MR-1 planktonic cells. As a consequence, the microbial fuel cells with C–WO 3 nanorods anode showed more stable performance than the pure carbon paper and WO 3 -nanoparticles systems in prolonged operation. This work suggests that WO 3 nanorods have the potential to be used as a robust and biofouling-resistant electrode material for practical bioelectrochemical applications

  2. Thermal expansion and pressure effect in MnWO4

    International Nuclear Information System (INIS)

    Chaudhury, R.P.; Yen, F.; Cruz, C.R. de la; Lorenz, B.; Wang, Y.Q.; Sun, Y.Y.; Chu, C.W.

    2008-01-01

    MnWO 4 has attracted attention because of its ferroelectric property induced by frustrated helical spin order. Strong spin-lattice interaction is necessary to explain ferroelectricity associated with this type of magnetic order. We have conducted thermal expansion measurements along the a, b, c axes revealing the existence of strong anisotropic lattice anomalies at T 1 =7.8 K, the temperature of the magnetic lock-in transition into a commensurate low-temperature (reentrant paraelectric) phase. The effect of hydrostatic pressure up to 1.8 GPa on the FE phase is investigated by measuring the dielectric constant and the FE polarization. The low-temperature commensurate and paraelectric phase is stabilized and the stability range of the ferroelectric phase is diminished under pressure

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

    Directory of Open Access Journals (Sweden)

    Chuan-Sheng Wu

    2015-07-01

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

  4. Solid-State Electrochromic Device Consisting of Amorphous WO3 and Various Thin Oxide Layers

    Science.gov (United States)

    Shizukuishi, Makoto; Shimizu, Isamu; Inoue, Eiichi

    1980-11-01

    A mixed oxide containing Cr2O3 was introduced into an amorphous WO3 solid-state electrochromic device (ECD) in order to improve its colour memory effect. The electrochromic characteristics were greatly affected by the chemical constituents of a dielectric layer on the a-WO3 layer. Particularly, long memory effect and low power dissipation were attained in a solid-state ECD consisting of a-WO3 and Cr2O3\\cdotV2O5(50 wt.%). Some electrochromic characteristics of the a-WO3/Cr2O3\\cdotV2O5 ECD and the role of V2O5 were investigated.

  5. A comparative study of heterostructured CuO/CuWO4 nanowires and thin films

    Science.gov (United States)

    Polyakov, Boris; Kuzmin, Alexei; Vlassov, Sergei; Butanovs, Edgars; Zideluns, Janis; Butikova, Jelena; Kalendarev, Robert; Zubkins, Martins

    2017-12-01

    A comparative study of heterostructured CuO/CuWO4 core/shell nanowires and double-layer thin films was performed through X-ray diffraction, confocal micro-Raman spectroscopy and electron (SEM and TEM) microscopies. The heterostructures were produced using a two-step process, starting from a deposition of amorphous WO3 layer on top of CuO nanowires and thin films by reactive DC magnetron sputtering and followed by annealing at 650 °C in air. The second step induced a solid-state reaction between CuO and WO3 oxides through a thermal diffusion process, revealed by SEM-EDX analysis. Morphology evolution of core/shell nanowires and double-layer thin films upon heating was studied by electron (SEM and TEM) microscopies. A formation of CuWO4 phase was confirmed by X-ray diffraction and confocal micro-Raman spectroscopy.

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

    CERN Document Server

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

    2004-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-08-02

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

  8. Characterization of WO3 Thin Films Grown on Silicon by HFMOD

    Directory of Open Access Journals (Sweden)

    Joel Díaz-Reyes

    2013-01-01

    modes of as-deposited WO3 and annealed at 500°C present clearly differences. WO3 band gap energy can be varied from 2.92 to 3.15 eV by annealing WO3 from 0 to 500°C as was obtained by transmittance measurements. The photoluminescence response of the as-deposited film presents three radiative transitions observed at 2.85, 2.41, and 2.04 eV that could be associated with oxygen vacancies; the first one is shifted to higher energies as the annealing temperature is increased due to the change of crystalline phase of the WO3.

  9. Structural and optical properties of WO{sub 3} films deposited by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Y.S., E-mail: yshzou75@gmail.com; Zhang, Y.C.; Lou, D.; Wang, H.P.; Gu, L.; Dong, Y.H.; Dou, K.; Song, X.F.; Zeng, H.B.

    2014-01-15

    Highlights: • Monoclinic WO{sub 3} films were prepared by pulsed laser deposition. • The WO{sub 3} films exhibited preferred (0 0 2) orientation at elevated temperature. • The structure and optical properties of WO{sub 3} films depended on substrate temperature. • The optical band gap of WO{sub 3} films decreased as substrate temperature increased. -- Abstract: Tungsten oxide (WO{sub 3}) films were prepared on Si (1 0 0) and fused silica substrates by pulsed laser deposition (PLD). The effects of substrate temperature on the morphology, microstructure and optical properties of WO{sub 3} films were investigated by scanning electron microscopy, atomic force microscopy, X-ray diffraction, Raman spectra and UV–visible spectrophotometer. It was found that the microstructure, morphology and optical properties strongly depend on the substrate temperature. The X-ray diffraction and Raman results indicate that the amorphous WO{sub 3} films are obtained at substrate temperatures below 200 °C whereas the films grown above 300 °C exhibit predominantly (0 0 2) plane orientation, representing the monoclinic structure. The surface roughness, film crystallinity and grain size of the films increase with increasing substrate temperature. The films prepared at substrate temperatures ranging from 300 to 600 °C exhibit high averaged transparency over 60% in the visible region. The optical band gaps of the films are found to decrease monotonically from 3.22 to 3.05 eV as the substrate temperature increases from 200 to 600 °C due to the crystallization of deposited WO{sub 3} film.

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

    Science.gov (United States)

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

    2017-03-01

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

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

    Science.gov (United States)

    Stembrowicz, W

    2001-01-01

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

  12. The novel phase transition of NaBi(WO4)2 under high pressure

    International Nuclear Information System (INIS)

    Ma, Chunli; Cui, Hang; Li, Fangfei; Wang, Jingshu; Wu, Xiaoxin; Zhang, Jian; Zhou, Qiang; Liu, Jinghe; Cui, Qiliang

    2013-01-01

    The Raman and synchrotron angle-dispersive X-ray diffraction studies have been performed on NaBi(WO 4 ) 2 under high pressure up to 30.7 and 36.2 GPa, respectively, at room temperature. With pressure increases to ∼7.0 GPa, the structure of NaBi(WO 4 ) 2 begins to transform from tetragonal (I4 1 /a) into monoclinic (P2/m), and the phase transition completes around 13 GPa. With pressure higher than 29.0 GPa, the NaBi(WO 4 ) 2 turns into amorphous state. The random arrangement of Na + and Bi 3+ in short-range ordered scheelite NaBi(WO 4 ) 2 results in the tetragonal to monoclinic phase transition, which is different from that observed in AWO 4 tungstates and AMoO 4 molybdates (A=Ca, Sr, Ba, Pb, Eu, Cd). - Graphical abstract: The NaBi(WO 4 ) 2 transforms from tetragonal into monoclinic, which starts around 7 GPa and completes at about 13 GPa. With pressure higher than 29 GPa, the NaBi(WO 4 ) 2 turns into amorphous state. Highlights: ► Raman and X-ray diffraction studies performed on NaBi(WO 4 ) 2 up to 30.7 and 36.2 GPa, respectively. ► The tetragonal (I4 1 /a) into monoclinic (P2/m) phase transition is determined. ► With pressure higher than 29 GPa, the NaBi(WO 4 ) 2 ultimately turns into amorphous state. ► The ambient pressure bulk modulus and volume of tetragonal and monoclinic phases are obtained

  13. UV-VUV synchrotron radiation spectroscopy of NiWO4

    Science.gov (United States)

    Kuzmin, A.; Pankratov, V.; Kalinko, A.; Kotlov, A.; Shirmane, L.; Popov, A. I.

    2016-07-01

    Photoluminescence and excitation spectra of microcrystalline and nanocrystalline nickel tungstate (NiWO4) were measured using UV-VUV synchrotron radiation source. The origin of the bands is interpreted using comparative analysis with isostructural ZnWO4 tungstate and based on the results of recent first-principles band structure calculations. The influence of the local atomic structure relaxation and of Ni2+ intra-ion d-d transitions on the photoluminescence band intensity are discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-15

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

  16. WO3 Nanowires on Graphene Sheets as Negative Electrode for Supercapacitors

    Directory of Open Access Journals (Sweden)

    Bo Liu

    2017-01-01

    Full Text Available WO3 nanowires directly grown on graphene sheets have been fabricated by using a seed-mediated hydrothermal method. The morphologies and electrochemical performance of WO3 films prepared by different process were studied. The results show that the precoated nanoseeds and graphene sheets on graphite electrode provide more reactive centers for the nucleation and formation of uniform WO3 nanowires. The WO3 nanowires electrode exhibits a high area specific capacitance of 800 mF cm−2 over negative potential range from −1.0 V to 0 V versus SCE in 1 M Li2SO4 solution. A high performance electrochemical supercapacitor assembled with WO3 nanowires as negative electrode and PANI/MnO2 as positive electrodes over voltage range of 1.6 V displays a high volumetric capacitance of 2.5 F cm−3, which indicate great potential applications of WO3 nanowires on graphene sheets as negative electrode for energy storage devices.

  17. A Resistive Humidity Sensor Based on Nanostructured WO3-ZnO Composites

    Directory of Open Access Journals (Sweden)

    Karunesh Tiwari

    2011-11-01

    Full Text Available Paper reports morphological and humidity sensing studies of WO3 and WO3-ZnO composite pellets prepared in the weight % ratio of 10:1, 4:1 and 2:1 by solid-state reaction route. The pellets have been annealed at temperatures of 300-500 °C. XRD pattern shows peaks of ZnWO4 formed due to solid state reaction between WO3 and ZnO. SEM micrographs show that the sensing elements manifest porous structure. Granulation and tendency to agglomerate seen in the SEM micrograph are due to the presence of zinc ions in ZnWO4. Nanoparticles are having their sizes in the range 37-182 nm. The average Kelvin radius at 20˚C room temperature is 27 Ả. Humidity sensing application of the pellets has been studied in a humidity control cabinet. It is observed that as relative humidity increases, there is decrease in the resistance of pellets in the range 10-85 % RH. Sensing element of WO3-ZnO in 2:1 weight % ratio shows best results in 10-85 % relative humidity range. The average sensitivity of this sample is 1.25 MΩ/%RH. This sensing element shows good reproducibility, low hysteresis and less effect of aging.

  18. Epitaxial NiWO4 films on Ni(110): Experimental and theoretical study of surface stability

    Science.gov (United States)

    Doudin, N.; Pomp, S.; Blatnik, M.; Resel, R.; Vorokhta, M.; Goniakowski, J.; Noguera, C.; Netzer, F. P.; Surnev, S.

    2017-05-01

    Despite the application potential of nickel tungstate (NiWO4) in heterogeneous catalysis, humidity and gas sensing, etc, its surfaces have essentially remained unexplored. In this work, NiWO4 nanoparticles and films with the wolframite structure have been grown via a solid-state reaction of (WO3)3 clusters and a NiO(100) film on a Ni(110) crystal surface and characterized by a variety of experimental techniques, including x-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM) and x-ray diffraction (XRD), combined with ab-initio density functional theory (DFT) calculations. NiWO4 grows initially as three-dimensional (3D) crystalline nanoparticles displaying mainly two crystalline facets vicinal to the (100) surface, which merge with increasing the (WO3)3 coverage into a quasi-continuous epitaxial film. The DFT results provide an account of the energetics of NiWO4 low index surfaces and highlight the role of faceting in the stabilization of extended polar (100) terraces. These combined experimental and theoretical results show that interaction with a metal substrate and vertical confinement may stabilize oxide nano-objects with high energy facets, able to enhance their reactivity.

  19. Morphology-controlled synthesis of CdWO4 nanorods and nanoparticles via a molten salt method

    International Nuclear Information System (INIS)

    Wang Yonggang; Ma Junfeng; Tao Jiantao; Zhu Xiaoyi; Zhou Jun; Zhao Zhongqiang; Xie Lijin; Tian Hua

    2006-01-01

    Cadmium tungstate (CdWO 4 ) nanoparticles and nanorods have been successfully synthesized by a molten salt method at 270 deg. C, and the morphology of the nanocrystals can be controlled by adjusting such reaction conditions as the calcined time and the weight ratio of the salt to the CdWO 4 precursor. The resultant sample is a pure phase of CdWO 4 without any other impurities

  20. Thermal effects associated with the Raman spectroscopy of WO3 gas-sensor materials.

    Science.gov (United States)

    Garcia-Sanchez, Raul F; Ahmido, Tariq; Casimir, Daniel; Baliga, Shankar; Misra, Prabhakar

    2013-12-19

    Metal oxides are suitable for detecting, through conductive measurements, a variety of reducing and oxidizing gases in environmental and sensing applications. Metal-oxide gas sensors can be developed with the goal of sensing gases under specific conditions and, as a whole, are heavily dependent on the manufacturing process. Tungsten oxide (WO3) is a promising metal-oxide material for gas-sensing applications. The purpose of this paper is to determine the existence of a correlation between thermal effects and the changes in the Raman spectra for multiple WO3 structures. We have obtained results utilizing Raman spectroscopy for three different structures of WO3 (monoclinic WO3 on Si substrate, nanopowder, and nanowires) that have been subjected to temperatures in the range of 30-160 °C. The major vibrational modes of the WO3:Si and the nanopowder samples, located at ~807, ~716, and ~271 cm(-1), correspond to the stretching of O-W-O bonds, the stretching of W-O, and the bending of O-W-O, respectively; these are consistent with a monoclinic WO3 structure. However in the nanowires sample only asymmetric stretching of the W-O bonds occurs, resulting in a 750 cm(-1) band, and the bending of the O-W-O mode (271 cm(-1)) is a stretching mode (239 cm(-1)) instead, suggesting the nanowires are not strictly monoclinic. The most notable effect of increasing the temperature of the samples is the appearance of the bending mode of W-OH bonds in the approximate range of 1550-1150 cm(-1), which is related to O-H bonding caused by humidity effects. In addition, features such as those at 750 cm(-1) for nanowires and at 492 and 670 cm(-1) for WO3:Si disappear as the temperature increases. A deeper understanding of the effect that temperature has on the Raman spectral characteristics of a metal oxide such as WO3 has helped to extend our knowledge regarding the behavior of metal oxide-gas interactions for sensing applications. This, in turn, will help to develop theoretical models for

  1. Degradation of organic dyes using spray deposited nanocrystalline stratified WO3/TiO2 photoelectrodes under sunlight illumination

    Science.gov (United States)

    Hunge, Y. M.; Yadav, A. A.; Mahadik, M. A.; Bulakhe, R. N.; Shim, J. J.; Mathe, V. L.; Bhosale, C. H.

    2018-02-01

    The need to utilize TiO2 based metal oxide hetero nanostructures for the degradation of environmental pollutants like Rhodamine B and reactive red 152 from the wastewater using stratified WO3/TiO2 catalyst under sunlight illumination. WO3, TiO2 and stratified WO3/TiO2 catalysts were prepared by a spray pyrolysis method. It was found that the stratified WO3/TiO2 heterostructure has high crystallinity, no mixed phase formation occurs, strong optical absorption in the visible region of the solar spectrum, and large surface area. The photocatalytic activity was tested for degradation of Rhodamine B (Rh B) and reactive red 152 in an aqueous medium. TiO2 layer in stratified WO3/TiO2 catalyst helps to extend its absorption spectrum in the solar light region. Rh B and Reactive red 152is eliminated up to 98 and 94% within the 30 and 40 min respectively at optimum experimental condition by stratified WO3/TiO2. Moreover, stratified WO3/TiO2 photoelectrode has good stability and reusability than individual TiO2 and WO3 thin film in the degradation of Rh B and reactive red 152. The photoelectrocatalytic experimental results indicate that stratified WO3/TiO2 photoelectrode is a promising material for dye removal.

  2. Synthesis and photoluminescence of Tb3+ Activated NaY(WO4)2 phosphors

    International Nuclear Information System (INIS)

    Liu, Xiaohua; Xiang, Wendou; Chen, Fengming; Zhang, Wei; Hu, Zhengfa

    2012-01-01

    Graphical abstract: The phosphor powders of NaY(WO 4 ) 2 :Tb 3+ were prepared by solid state reaction. The dependence of luminescence intensity on the Tb 3+ concentration was investigated. Highlights: ► We synthesize NaY(WO 4 ) 2 :Tb 3+ phosphors by the solid-state reaction technique. ► We observe and explain the blue shifting of excitation peak positions of CTBs. ► The PL from 5 D 3 level become less probable with increasing the Tb 3+ content. ► The PL intensity increases with Tb 3+ content without concentration quenching. ► NaY(WO 4 ) 2 :Tb 3+ has potential application as a green emitting phosphor in lamps. -- Abstract: The novel yellowish green phosphor powders of NaY(WO 4 ) 2 doped with Tb 3+ were prepared by solid-state reaction. The powder samples were characterized by X-ray diffraction and photoluminescence. X-ray diffraction analysis showed that the phosphors sintered at 900 °C for 6 h were a pure NaY(WO 4 ) 2 phase for all the Tb 3+ doping concentrations. The room temperature excitation spectra vary with the Tb 3+ concentration and consist of an intense charge transfer band of WO 4 2− group and weak intra-4f 8 transition absorption peaks of Tb 3+ ions. The photoluminescence spectra, excited at the peak wavelengths of charge transfer bands, consist of the characteristic Tb 3+ emission transitions from 5 D 3 and 5 D 4 excited levels to 7 F J (J = 3–6) levels. The dependence of luminescence intensity on the Tb 3+ concentration in NaY(WO 4 ) 2 :Tb phosphors was investigated.

  3. Evaluate humidity sensing properties of novel TiO2–WO3 composite material

    International Nuclear Information System (INIS)

    Lin, Wang-De; Lai, De-Sheng; Chen, Min-Hung; Wu, Ren-Jang; Chen, Fu-Chou

    2013-01-01

    Graphical abstract: TiO 2 –WO 3 (1:1) showed better humidity sensing properties than others within the range of 12–90% relative humidity (RH), the response and recovery time were about 20 s and 160 s, respectively. Compared to the previous studies, the prepared sensor exhibits higher sensitivity (S = 451) and the low hysteresis value was around 0.13% at 32% RH. - Highlights: • Novel TiO 2 –WO 3 composite material was prepared for humidity sensor. • The sensor exhibits higher sensitivity (S = 451). • Low hysteresis value was around 0.13% at 32% RH. - Abstract: A novel TiO 2 –WO 3 composite material was prepared using a different proportion of TiO 2 and WO 3 to that investigated in previous studies. The obtained mesoporous material was characterized using X-ray diffraction, Fourier transform infrared spectrometry, transmission electron microscopy, energy dispersive X-ray spectroscopy, and N 2 adsorption-desorption techniques. The humidity-sensing properties were measured using an inductance, capacitance and resistance analyzer. The results demonstrated that the TiO 2 –WO 3 sample with a ratio of 1:1 showed better humidity sensing properties. Compared to previous studies, the prepared sensor exhibited higher sensitivity (S = 451) and the lower hysteresis value was around 0.13% at 32% RH. Complex impedance analysis indicated that the enhanced humidity sensitivity was probably due to spherical Brunauer–Emmett–Teller surface area and the hetero-junction between TiO 2 –WO 3 thin films, while the impedance varied about three orders of magnitude. Our results demonstrated the potential application of TiO 2 –WO 3 composite for fabricating high performance humidity sensors

  4. On tungstates of divalent cations (II). Polymorphy of Pb{sub 2}WO{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Jantz, Stephan G.; Dialer, Marwin; Hoeppe, Henning A. [Lehrstuhl fuer Festkoerperchemie, Universitaet Augsburg (Germany); Pielnhofer, Florian [Abteilung Nanochemie, Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)

    2017-12-13

    The phase transition from the low temperature form Pb{sub 2}[WO{sub 5}] to its high temperature form Pb{sub 2}O[WO{sub 4}] was monitored by means of temperature dependent powder XRD. Single-crystals of Pb{sub 2}[WO{sub 5}], suitable for a structure determination by single-crystal X-ray diffraction, were obtained by quenching a sample from 500 C to room temperature. The low-temperature phase Pb{sub 2}[WO{sub 5}] comprises the structural motive of infinite zigzag chains built by cornersharing WO{sub 6} octahedra, known from the tungstates M{sub 2}[WO{sub 5}] (M = Sr, Ba), but crystallizes in a new structure type [C2/c, a = 14.0996(4) Aa, b = 5.8579(2) Aa, c = 12.6877(4) Aa, β = 114.3569(13) , Z = 8, R{sub int} = 0.042, R{sub 1} = 0.040, wR{sub 2} = 0.068]. The crystal structure of the high-temperature phase Pb{sub 2}O[WO{sub 4}] [C2/m, a = 14.2126(4) Aa, b = 5.80150(10) Aa, c = 7.3477(2) Aa, β = 113.9402(7) , Z = 4, R{sub 1} = 0.035, wR{sub 2} = 0.055] is revised, based on single-crystal XRD data. Furthermore spectroscopic data (IR, Raman and UV/Vis spectra) are presented. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Structural evolution, growth mechanism and photoluminescence properties of CuWO4nanocrystals.

    Science.gov (United States)

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

    2017-09-01

    Copper tungstate (CuWO 4 ) 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 (CuWO 4 ·2H 2 O) with monoclinic structure), when the crystals are calcinated at 300°C have the presence of two phase (CuWO 4 ·2H 2 O and CuWO 4 ), while the others heat treated at 400°C and 500°C have a single CuWO 4 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 CuWO 4 ·2H 2 O and CuWO 4 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.

  6. Preparation of tungsten coatings on graphite by electro-deposition via Na2WO4–WO3 molten salt system

    International Nuclear Information System (INIS)

    Sun, Ning-bo; Zhang, Ying-chun; Jiang, Fan; Lang, Shao-ting; Xia, Min

    2014-01-01

    Highlights: • Tungsten coatings on graphite were firstly obtained by electro-deposition method via Na 2 WO 4 –WO 3 molten salt system. • Uniform and dense tungsten coatings could be easily prepared in each face of the sample, especially the complex components. • The obtained tungsten coatings are with high purity, ultra-low oxygen content (about 0.022 wt%). • Modulate pulse parameters can get tungsten coatings with different thickness and hardness. - Abstract: Tungsten coating on graphite substrate is one of the most promising candidate materials as the ITER plasma facing components. In this paper, tungsten coatings on graphite substrates were fabricated by electro-deposition from Na 2 WO 4 –WO 3 molten salt system at 1173 K in atmosphere. Tungsten coatings with no impurities were successfully deposited on graphite substrates under various pulsed current densities in an hour. By increasing the current density from 60 mA cm −2 to 120 mA cm −2 an increase of the average size of tungsten grains, the thickness and the hardness of tungsten coatings occurs. The average size of tungsten grains can reach 7.13 μm, the thickness of tungsten coating was in the range of 28.8–51 μm, and the hardness of coating was higher than 400 HV. No cracks or voids were observed between tungsten coating and graphite substrate. The oxygen content of tungsten coating is about 0.022 wt%

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-15

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

  8. Multiferroic hysteresis in MnWO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Finger, Thomas; Komarek, Alexander; Senff, Daniel; Braden, Markus [II. Physikalisches Institut, Universitaet zu Koeln (Germany); Becker-Bohaty, Petra; Bohaty, Ladislav [Institut fuer Kristallographie, Universitaet zu Koeln (Germany); Regnault, Louis-Pierre [CNG-Grenoble / ILL, Grenoble (France); Schmalzl, Karin; Schmidt, Wolfgang [JCNS / ILL, Grenoble (France)

    2009-07-01

    Multiferroic materials or compounds with a strong magnetoelectric effect posses a large application potential in data storage techniques: one would like to replace the common magnetic writing by an electric process, as the generation of the magnetic fields is energy expensive. Quite recently, systems with a peculiar spiral magnetic order were shown to directly induce a spontaneous electric polarization and to exhibit giant magnetoelectric and magnetocapacitance effects, among them MnWO{sub 4}, which crystallizes in a monoclinic structure and undergoes several magnetic phase transitions as a function of temperature. From these phases only the incommensurate non-collinear ordering in the AF2-phase induces an electric polarization and large magnetoelectric effects, fully consistent with recent theories. We have succeeded for the first time to observe a chirality hysteresis curve driven by the electric field. These data can give important information about the pinning of the multiferroic order, which is relevant in view of future applications. We present our temperature dependent studies on the multiferroic hysteresis as well as a characterization of the second harmonics of the spiral.

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

    Directory of Open Access Journals (Sweden)

    Yong Pan

    2015-05-01

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

  10. Nest-like structures of Sr doped Bi2WO6: Synthesis and enhanced photocatalytic properties

    International Nuclear Information System (INIS)

    Liu Ying; Wang Weimin; Fu Zhengyi; Wang Hao; Wang Yucheng; Zhang Jinyong

    2011-01-01

    Highlights: → Bi 2 WO 6 with 3D nest-like structures was obtained without the presence of templates but after Sr-doping, which represents a marked improvement over previous reports. → The products showed enhanced photocatalytic properties over pure Bi 2 WO 6 . → Samples subsequently thermal treated at 500 deg. C show better photocatalytic activities. - Abstract: A series of Sr-doped Bi 2 WO 6 with three-dimensional (3D) nest-like structures were synthesized through simple hydrothermal route and characterized by XRD, FESEM, TEM, XPS, UV-vis DRS, etc. Morphology observation revealed that the as-synthesized Bi 2 WO 6 were self-assembled three-dimensional (3D) nest-like structures, which were constructed from nanoplates. UV-vis diffuse reflectance spectra indicated that the samples had absorption in both UV and visible light areas. Their photocatalytic activities were evaluated by photodegradation of rhodamine B (RhB) under UV and visible light irradiation (λ > 420 nm). The photocatalytic properties were enhanced after Sr doping. Samples subsequently thermal treated at 500 deg. C showed higher photocatalytic activities. The reasons for the differences in the photocatalytic activities of these nest-like Bi 2 WO 6 microstructures were further investigated.

  11. Direct solar water splitting cell using water, WO3, Pt, and polymer electrolyte membrane

    International Nuclear Information System (INIS)

    He Xiaoming; Boehm, Robert F.

    2009-01-01

    A solar water splitting cell composed of WO 3 , Polymer Electrolyte Membrane (PEM) and Pt was constructed for producing hydrogen from deionized water in sunlight. Spectral responsivity measurements under various temperatures and bias voltages were conducted for the cell using the Incident Photon to Current Efficiency (IPCE) method. For comparison, a known WO 3 Photo Electro Chemical (PEC) cell containing H 3 PO 4 electrolyte, WO 3 /H 3 PO 4 /Pt, was tested using the same test method. The WO 3 /PEM-H 2 O/Pt cell showed better Quantum Efficiency (QE) performance compared to that obtained from the cell with the chemical electrolyte. For the first time, spectral responsivity of photo water splitting process without bias power was unveiled in the new WO 3 cell, demonstrating the self-sustained photo electrolysis capability. Bias voltage effect on Solar to Hydrogen (STH) conversion efficiency was dramatic in the range from 0.2 V to 1.2 V and suppressions of STH were observed when high bias voltages were applied. In addition, a strong temperature effect on the energy conversion efficiency at high bias voltage was observed in the cell containing PEM-H 2 O, revealing that the STH at 54 °C is nearly five times that at 14 °C.

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

    CERN Document Server

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

    2001-01-01

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

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

    CERN Document Server

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

    2002-01-01

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

  14. Cycloidal magnetism driven ferroelectricity in double tungstate LiFe (WO4)2

    Science.gov (United States)

    Liu, Meifeng; Lin, Lingfang; Zhang, Yang; Li, Shaozhen; Huang, Qingzhen; Garlea, V. Ovidiu; Zou, Tao; Xie, Yunlong; Wang, Yu; Lu, Chengliang; Yang, Lin; Yan, Zhibo; Wang, Xiuzhang; Dong, Shuai; Liu, Jun-Ming

    2017-05-01

    Tungstates A WO4 with the wolframite structure characterized by the A O6 octahedral zigzag chains along the c axis can be magnetic if A =Mn , Fe, Co, Cu, Ni. Among them, MnWO4 is a unique member with a cycloid Mn2 + spin order developed at low temperature, leading to an interesting type-II multiferroic behavior. However, so far no other multiferroic material in the tungstate family has been found. In this work, we present the synthesis and the systematic study of the double tungstate LiFe (WO4)2 . Experimental characterizations including structural, thermodynamic, magnetic, neutron powder diffraction, and pyroelectric measurements unambiguously confirm that LiFe (WO4)2 is the secondly found multiferroic system in the tungstate family. The cycloidal magnetism driven ferroelectricity is also verified by density functional theory calculations. Although here the magnetic couplings between Fe ions are indirect, namely via the so-called super-super-exchanges, the temperatures of magnetic and ferroelectric transitions are surprisingly much higher than those of MnWO4.

  15. Photocatalytic decomposition of N2O over g-C3N4/WO3photocatalysts.

    Science.gov (United States)

    Reli, Martin; Svoboda, Ladislav; Šihor, Marcel; Troppová, Ivana; Pavlovský, Jiří; Praus, Petr; Kočí, Kamila

    2017-11-24

    Although the nitrous oxide belongs among three of the most contributing greenhouse gases to global warming, it is quite neglected by photocatalytic society. The g-C 3 N 4 and WO 3 composites were therefore tested for the photocatalytic decomposition of N 2 O for the first time. The pure photocatalysts were prepared by simple calcination of precursors, and the composites were prepared by mixing of suspension of pure components in water followed by calcination. The structural (X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy), textural (N 2 physisorption), and optical properties (diffuse reflectance spectroscopy, photoluminescence spectroscopy, photoelectrochemical measurements) of all composites were correlated with photocatalytic activity. The experimental results and results from characterization techniques confirmed creation of Z-scheme in the WO 3 /g-C 3 N 4 composites, which was confirmed by hydroxyl radicals' trapping measurements. The photocatalytic decomposition of N 2 O was carried out in the presence of UVA light (peak intensity at 365 nm) and the 1:2 WO 3 /g-C 3 N 4 composite was the most active one, but the photocatalytic activity was just negligibly higher than that of pure WO 3 . This is caused by relatively weak interaction between WO 3 and g-C 3 N 4 which was revealed from XPS.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  17. Characterization of PLD grown WO3 thin films for gas sensing

    Science.gov (United States)

    Boyadjiev, Stefan I.; Georgieva, Velichka; Stefan, Nicolaie; Stan, George E.; Mihailescu, Natalia; Visan, Anita; Mihailescu, Ion N.; Besleaga, Cristina; Szilágyi, Imre M.

    2017-09-01

    Tungsten trioxide (WO3) thin films were grown by pulsed laser deposition (PLD) with the aim to be applied in gas sensors. The films were studied by atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and profilometry. To study the gas sensing behavior of these WO3 films, they were deposited on quartz resonators and the quartz crystal microbalance (QCM) method was applied to analyze their gas sensitivity. Synthesis of tetragonal-WO3 films starting from a target with predominantly monoclinic WO3 phase was observed. The films deposited at 300 °C presented a surface topology favorable for the sorption properties, consisting of a film matrix with protruding craters/cavities. QCM prototype sensors with such films were tested for NO2 sensing. The PLD grown WO3 thin films show good sensitivity and fast reaction at room temperature, even in as-deposited state. With the presented technology, the manufacturing of QCM gas sensors is simple, fast and cost-effective, and it is also suitable for energy-effective portable equipment for on-line monitoring of environmental changes.

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

    Science.gov (United States)

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

    2017-01-01

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

  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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-15

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

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

    CSIR Research Space (South Africa)

    Makgwane, PR

    2014-09-01

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

  1. Comparative studies of monoclinic and orthorhombic WO3 films used for hydrogen sensor fabrication on SiC crystal

    International Nuclear Information System (INIS)

    Zuev, V V; Romanov, R I; Fominski, V Y; Grigoriev, S N; Volosova, M A; Demin, M V

    2016-01-01

    Amorphous WO x films were prepared on the SiC crystal by using two different methods, namely, reactive pulsed laser deposition (RPLD) and reactive deposition by ion sputtering (RDIS). After deposition, the WO x films were annealed in an air. The RISD film possessed a m-WO 3 structure and consisted of closely packed microcrystals. Localized swelling of the films and micro-hills growth did not destroy dense crystal packing. RPLD film had layered β-WO 3 structure with relatively smooth surface. Smoothness of the films were destroyed by localized swelling and the micro-openings formation was observed. Comparative study of m-WO 3 /SiC, Pt/m-WO 3 /SiC, and P-WO 3 /SiC samples shows that structural characteristics of the WO 3 films strongly influence on the voltage/current response as well as on the rate of current growth during H 2 detection at elevated temperatures. (paper)

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

    CSIR Research Space (South Africa)

    Chakraborty, AK

    2012-06-01

    Full Text Available nanorod. The prepared Au loaded MnWO4 nanorod demonstrated greatly enhanced photocatalytic activity in decomposing 2-propanol and evolving CO2 in gas phase and phenol in aqueous phase compared to bare MnWO4 and commercial TiO2 nanoparticles (Degussa P25...

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

    NARCIS (Netherlands)

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

    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

  4. Light-induced spatial separation of charges toward different crystal facets of square-like WO3.

    Science.gov (United States)

    Gong, Huihua; Ma, Ruirui; Mao, Fang; Liu, Kewei; Cao, Hongmei; Yan, Hongjian

    2016-09-29

    Light-induced preferential migration of electrons and holes to the minor (200) and (020) facets and the dominant (002) facets of square-like WO 3 , respectively, resulted in the square-like WO 3 nanoplates with Pt loaded mainly on dominant (002) facets shows higher photocatalytic activity than that Pt loaded on the minor facets.

  5. Optical characterization of the coloration process in electrochromic amorphous and crystalline WO3 films by spectroscopic ellipsometry

    Science.gov (United States)

    Yuan, Guangzhong; Hua, Chenzheng; Huang, Li; Defranoux, Christophe; Basa, Peter; Liu, Yong; Song, Chenlu; Han, Gaorong

    2017-11-01

    Amorphous and crystalline electrochromic WO3 films exhibit quite different optical properties during coloration process. In the present work, amorphous and crystalline electrochromic WO3 films prepared by a solution method were characterized using X-ray diffraction, scanning electron microscope, and transmission electron microscope techniques. A double-layer model with sharp interfaces was established for the fitting of the ellipsometry parameters. The results show that the proton favors amorphous films more than crystalline WO3 films. The refractive indices of both amorphous and polycrystalline WO3 films decrease while extinction coefficients increase with the inserting of H+ during the coloration process. But the optical parameters of the latter are much more sensitive to the H+ ions injected compared to the amorphous WO3 during the coloration process. That is the refractive index modulation of the crystalline WO3 films is about 53% at 633 nm while that of the amorphous films about 15% at the same wavelength. The Drude-like free electron model for crystalline WO3 and hopping mechanism of small polaron for amorphous WO3 are used to explain the difference in detail. These results are very helpful for the better understanding of the coloration process and for the design of electrochromic devices.

  6. Study of phase equilibria and glass formation in the CaO-WO3-P2O5 system

    International Nuclear Information System (INIS)

    Bielis, I.Ya.

    1980-01-01

    The method of quenching has been used to investigate the liquidus surface of a portion of the CaO-WO 3 -P 2 O 5 system limited by the Ca(PO 3 ) 2 -W 2 O 3 (PO 4 ) 2 and CaWO 4 -Ca 2 P 2 O 7 cross-sections. The primary crystallization fields on the compounds: WO 3 , W 2 O 3 (PO 4 ) 2 , CaWO 4 , Ca 2 P 7 O 7 , Ca(PO 3 ) 2 are separated. The liquidus surface isotherms at 900, 1000, 1100 and 1200 deg C have been plotted on the concentration triangle plane. It has been found that the cross-sections of W 2 O 3 (PO 4 ) 2 -Ca(PO 3 ) 2 , WO 3 -Ca(PO 3 ) 2 , WO 3 -Ca 2 P 2 O 7 and CaWO 4 -Ca 2 P 2 O 7 are eutectic-type quasi-binary systems. The position of the glass transition region in the CaO-WO 3 -P 2 O 5 system has been determined for the treatment temperatures of 1100, 1200 and 1300 deg C and a correlation between the configuration of the glass transition region and the phase diagram of the system has been demonstrated [ru

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

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Reyes, J., E-mail: jdiazr2001@yahoo.com [Centro de Investigacion en Biotecnologia Aplicada del Instituto Politecnico Nacional, Ex-Hacienda de San Juan Molino, Km. 1.5, Tepetitla, Tlaxcala, 90700 (Mexico); Delgado-Macuil, R.J. [Centro de Investigacion en Biotecnologia Aplicada del Instituto Politecnico Nacional, Ex-Hacienda de San Juan Molino, Km. 1.5, Tepetitla, Tlaxcala, 90700 (Mexico); Dorantes-Garcia, V. [Preparatoria ' Simon Bolivar' de la Benemerita Universidad Autonoma de Puebla, 4 Oriente 408, Col. Centro, Atlixco, Puebla, C. P. 74200 (Mexico); Perez-Benitez, A. [Facultad de Ciencias Quimicas de la Benemerita Universidad Autonoma Puebla, 14 Sur y Av. San Claudio, Col. San Manuel, Puebla, Puebla, C. P. 72570 (Mexico); Balderas-Lopez, J.A. [Unidad Profesional Interdisciplinaria de Biotecnologia del Instituto Politecnico Nacional, Avenida Acueducto S/N, Col. Barrio la Laguna, Ticoman, Del. Gustavo A. Madero, Mexico, D.F. 07340 (Mexico); Ariza-Ortega, J.A. [Centro de Investigacion en Biotecnologia Aplicada del Instituto Politecnico Nacional, Ex-Hacienda de San Juan Molino, Km. 1.5, Tepetitla, Tlaxcala, 90700 (Mexico)

    2010-10-25

    WO{sub 3} is grown by hot-filament metal oxide deposition (HFMOD) technique under atmospheric pressure and an oxygen atmosphere. By X-ray diffraction obtains that WO{sub 3} presents mainly monoclinic crystalline phase. The chemical stoichiometry is obtained by X-ray Photoelectron Spectroscopy (XPS). The IR spectrum of the as-grown WO{sub 3} presents broad peaks in the range of 1100 to 3600 cm{sup -1}. A broad band in the 2200 to 3600 cm{sup -1} region and the peaks sited at 1645 and 1432 cm{sup -1} are well resolved, which are originated from moisture and are assigned to {nu}(OH) and {delta}(OH) modes of adsorbed water and the corresponding tungsten oxide vibrations are in infrared region from 400 to 1453 cm{sup -1} and around 3492 cm{sup -1}, which correspond to tungsten-oxygen (W-O) stretching, bending and lattice modes. The Raman spectrum shows intense peaks at 801, 710, 262 and 61 cm{sup -1} that are typical Raman peaks of crystalline WO{sub 3} (m-phase) that correspond to stretching vibrations of the bridging oxygen, which are assigned to W-O stretching ({nu}) and W-O bending ({delta}) modes, respectively. By transmittance measurements obtains that the WO{sub 3} band gap can be varied from 2.92 to 3.13 eV in the investigated annealing temperature range.

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

    Energy Technology Data Exchange (ETDEWEB)

    Flores M, J. E. [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias de la Electronica, Av. San Claudio y 18 Sur, Ciudad Universitaria, Col. Jardines de San Manuel, 72570 Puebla (Mexico); Diaz R, J. [IPN, Centro de Investigacion en Biotecnologia Aplicada, Ex-Hacienda de San Molino Km 1.5 Tepetitla, 90700 Tlaxcala (Mexico); Balderas L, J. A., E-mail: eflores@ece.buap.mx [IPN, Unidad Profesional Interdisciplinaria de Biotecnologia, Av. Acueducto s/n, Col. Barrio la Laguna, 07340 Mexico D. F. (Mexico)

    2012-07-01

    In this work presents a study of the effect of the annealing temperature on structural and optical properties of WO{sub 3} that has been grown by hot-filament metal oxide deposition. The chemical stoichiometry was determined by X-ray photoelectron spectroscopy. By X-ray diffraction obtained that the as-deposited WO{sub 3} films present mainly monoclinic crystalline phase. WO{sub 3} optical band gap energy can be varied from 2.92 to 3.15 eV obtained by transmittance measurements by annealing WO{sub 3} from 100 to 500 C. The Raman spectrum of the as-deposited WO{sub 3} film shows four intense peaks that are typical Raman peaks of crystalline WO{sub 3} (m-phase) that corresponds to the stretching vibrations of the bridging oxygen that are assigned to W-O stretching ({upsilon}) and W-O bending ({delta}) modes, respectively, which enhanced and increased their intensity with the annealing temperature. (Author)

  9. Bibliometric analysis of publications on wine tourism in the databases Scopus and WoS

    Directory of Open Access Journals (Sweden)

    Amador Durán Sánchez

    2017-01-01

    Full Text Available The aim of this study was to show the current state of scientific research regarding wine tourism, by comparing the platforms of scientific information WoS and Scopus and applying quantitative methods. For this purpose, a bibliometric study of the publications indexed in WoS and Scopus was conducted, analyzing the correlation between increases, coverage, overlap, dispersion and concentration of documents. During the search process, a set of 238 articles and 122 different journals were obtained. Based 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.

  10. Preparation and magnetic properties of CoWO{sub 4} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Jiwei; Zhang, Endi; Ma, Jianmin; Wang, Taihong [Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, State Key Laboratory for Chemo/Biosensing and Chemometrics, Hunan University, Changsha (China); Chang, Liao [National Oceanography Centre, University of Southampton, European Way, Southampton (United Kingdom); Wang, Ping [Department of Biology and Chemistry, City University of Hong Kong, Hong Kong (China)

    2012-09-15

    Cobalt tungstate (CoWO{sub 4}) nanocrystals with an average size of 20-50 nm were synthesized via a template- or surfactant-free hydrothermal route. The crystal structure and morphology of the as-synthesized CoWO{sub 4} sample were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Magnetic measurements on the as-synthesized CoWO{sub 4} nanocrystals indicate a Neel temperature (T{sub N}) of {proportional_to}40 K. This lower T{sub N} may be a result of the nanostructured particles that reduce the exchange coupling. The new synthetic route presented in this paper has potential applications to fabricate other metal tungstates (MWO{sub 4}) materials. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. High-pressure Raman study and lattice dynamical calculations for SrWO4

    International Nuclear Information System (INIS)

    Christofilos, D; Papagelis, K; Ves, S; Kourouklis, G A; Raptis, C

    2002-01-01

    A high-pressure Raman study of SrWO 4 reveals a pressure induced phase transition starting at 11.5 GPa. Several Raman lines exhibit a nonlinear behaviour in the pressure range of 11.5-15 GPa, which can be attributed to either stabilization of the high-pressure phase or an intermediate phase. Using a theoretical lattice dynamical calculation, based on an empirical potential model, we have obtained the Raman active mode eigenvectors giving us an insight into the phase transition mechanism. The lowest-frequency mode exhibits a negative pressure slope in the scheelite phase and involves a motion of the WO 4 tetrahedron as a whole according to the theoretical results. The experimental evidence suggests that the structure of the high-pressure phase is closely related to the scheelite structure, being formed by closely lying distorted WO 4 tetrahedra rather than involving an octahedrally coordinated W ion

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

    CERN Document Server

    Deng, Q; Zhu, R Y

    1999-01-01

    This report presents the result of a study on radiation-induced color center densities in La-doped lead tungstate (PbWO sub 4) crystals. The creation and annihilation constants of radiation-induced color centers were determined by using transmittance data measured for a PbWO sub 4 sample before and during sup 6 sup 0 Co gamma-ray irradiation at a dose rate of 15 rad/h. Following a model of color center kinetics, these constants were used to calculate color center densities under irradiations at 100 rad/h. The result was found to be in good agreement with experimental data, indicating that the behaviour of PbWO sub 4 crystals under irradiation can be predicted according to this model.

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

    Directory of Open Access Journals (Sweden)

    Anna Staerz

    2016-10-01

    Full Text Available 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.

  14. Giant Persistent Photoconductivity of the WO3 Nanowires in Vacuum Condition

    Directory of Open Access Journals (Sweden)

    Huang Kai

    2011-01-01

    Full Text Available Abstract A giant persistent photoconductivity (PPC phenomenon has been observed in vacuum condition based on a single WO3 nanowire and presents some interesting results in the experiments. With the decay time lasting for 1 × 104 s, no obvious current change can be found in vacuum, and a decreasing current can be only observed in air condition. When the WO3 nanowires were coated with 200 nm SiO2 layer, the photoresponse almost disappeared. And the high bias and high electric field effect could not reduce the current in vacuum condition. These results show that the photoconductivity of WO3 nanowires is mainly related to the oxygen adsorption and desorption, and the semiconductor photoconductivity properties are very weak. The giant PPC effect in vacuum condition was caused by the absence of oxygen molecular. And the thermal effect combining with oxygen re-adsorption can reduce the intensity of PPC.

  15. Ag induced modifications on WO3 films studied by AFM, Raman and x-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Bittencourt, C; Llobet, E; Ivanov, P; Vilanova, X; Correig, X; Silva, M A P; Nunes, L A O; Pireaux, J J

    2004-01-01

    In this paper, the morphology, vibrational spectra and electronic properties of WO 3 films loaded with different levels of Ag, prepared by screen printing onto Si substrates and annealed in air at 600 deg. C were investigated. AFM micrography showed that the films are grain-like, and the grain size increases with an increase in the Ag loading level. Raman spectroscopy results showed the formation of a AgWO 3 bronze structure that results in a more stable film. X-ray photoelectron spectroscopy results showed that the Ag concentration is 1.8 times higher than the nominal concentration indicating that Ag diffuses to the WO 3 grain surface. No strong electronic interaction between the Ag clusters and the WO 3 grains was found. Sensors fabricated with the WO 3 : Ag films exhibited a significant increase in their sensitivity and selectivity towards NO 2 detection

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

    Energy Technology Data Exchange (ETDEWEB)

    Garde, Arun S, E-mail: arungarde@yahoo.co.in

    2014-12-25

    Highlights: • Polycrystalline WO{sub 3} Thick films are fabricated by screen printing technique. • Monoclinic phases were the majority in formation of films. • The peak at 1643 cm{sup −1} shows stretching vibrations attributed to W-OH of adsorbed H{sub 2}O. • Absorption peaks in the range 879–650 cm{sup −1} are attributed to the stretching W-O-W bonds. • Increase in resistance with decrease in RH when exposed to 20–100% RH. - Abstract: Thick films of tungsten oxide based were prepared using standard screen printing technique. To study the effect of temperature on the thick films were fired at different temperature for 30 min in air atmosphere. The WO{sub 3} thick films were characterized with X-ray diffraction, scanning electron microscopy and EDAX for elemental analysis. The formation of mixed phases of the film together with majority of monoclinic phase was observed. IR spectra confirm the peak at 1643 cm{sup −1} clearly shows stretching vibrations attributed to the W-OH bending vibration mode of the adsorbed water molecules. The absorption peaks in the range 879–650 cm{sup −1} are attributed to the stretching W-O-W bonds (i.e. ν [W-O{sub inter}-W]). The peak located at 983 cm{sup −1} belong to W=O terminal of cluster boundaries. A change in the resistance was observed with respect to the relative humidity when the WO{sub 3} thick films were exposed to a wide humidity range of 20–100%. An increasing firing temperature of WO{sub 3} film increases with the sensitivity. The parameters such as sensitivity and hysteresis of the WO{sub 3} film sensors have been evaluated.

  17. Conductive surface modification of cauliflower-like WO{sub 3} and its electrochemical properties for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sukeun, E-mail: skyoon@kongju.ac.kr [Division of Advanced Materials Engineering, Kongju National University, Chungnam 330-717 (Korea, Republic of); Woo, Sang-Gil [Advanced Batteries Research Center, Korea Electronics Technology Institute, Gyeonggi 463-816 (Korea, Republic of); Jung, Kyu-Nam [Energy Efficiency and Materials Research Division, Korea Institute of Energy Research, Daejeon 305-343 (Korea, Republic of); Song, Huesup, E-mail: hssong@kongju.ac.kr [Division of Advanced Materials Engineering, Kongju National University, Chungnam 330-717 (Korea, Republic of)

    2014-11-15

    Highlights: • Synthesis of cauliflower-like carbon-decorated WO{sub 3}. • Superior cyclability and rate capability for cauliflower-like carbon-decorated WO{sub 3}. • Electrochemical reaction behavior of cauliflower-like carbon-decorated WO{sub 3} with lithium. • In-situ XRD analysis during the first discharge–charge shows a complex reaction of intercalation and conversion of WO{sub 3}. - Abstract: Cauliflower-like WO{sub 3} was synthesized by a hydrothermal reaction without a surfactant, followed by firing, and was investigated as an anode material for lithium-ion battery applications. The scanning electron microscope (SEM) and transmission electron microscope (TEM) characterization indicated that WO{sub 3} nanorods had an aggregation framework and built a cauliflower morphology. With the objective of understanding the charge–discharge process within a voltage range of 0–3 V vs. Li{sup +}/Li, in situ X-ray diffraction was used and a complex reaction of intercalation and conversion of WO{sub 3} was revealed for the first time. The cauliflower-like WO{sub 3} after being decorated with carbon provides a high gravimetric capacity of >635 mA h/g (Li{sub 5.5}WO{sub 3}) with good cycling and a high rate capability when used as an anode in lithium-ion batteries. Based on our studies, we attribute the high electrochemical performance to the nanoscopic WO{sub 3} particles and a conductive carbon layer, which makes them a potential candidate for lithium-ion batteries.

  18. Polarized spectroscopic properties of Nd3+-doped KGd(WO4)2 single crystal

    International Nuclear Information System (INIS)

    Chen Yujin; Lin Yanfu; Gong Xinghong; Tan Qiguang; Zhuang Jian; Luo Zundu; Huang Yidong

    2007-01-01

    The polarized absorption spectra, infrared fluorescence spectra, upconversion visible fluorescence spectra, and fluorescence decay curve of orientated Nd 3+ :KGd(WO 4 ) 2 crystal were measured at room-temperature. Some important spectroscopic parameters were investigated in detail in the framework of the Judd-Ofelt theory and the Fuchtbauer-Ladenburg formula. The effect of the crystal structure on the spectroscopic properties of the Nd 3+ ions was analyzed. The relation among the spectroscopic parameters and the laser performances of the Nd 3+ :KGd(WO 4 ) 2 crystal was discussed

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

    CERN Document Server

    Pagnier, T

    2003-01-01

    High-pressure polymorphs of WO sub 3 have been studied with a first-principles pseudopotential method. The medium-range (0.01-20 GPa) and high-range (20-30 GPa) polymorphs have been characterized and are compared with recent experimental results. The main new feature is the appearance of a sevenfold coordinated tungsten in the high-pressure polymorph. The subtle phase transitions that were induced from Raman spectra evolutions have not been confirmed. However, changes in the W-O distances and O-W-O and W-O-W angles may explain the changes in Raman spectra.

  20. Cellulose-Based WO3 Nanocomposites Prepared by a Sol–Gel Method at Low Temperature

    Science.gov (United States)

    Zhang, Bin; Liu, Rongzhan; Pan, Ying; Wang, Quanquan; Liu, Baojiang

    2018-01-01

    A facile method was developed to prepare cellulose-based WO3 nanocomposites. The preparation was carried out by a sol-gel method by involving treatment of tungsten hexachloride and tri-block nonionic polymer at the temperature as low as 100 °C. The morphology, surface chemical composition, functional groups, and crystal phase of the as- prepared cellulose-based WO3 nanocomposites were investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction, respectively.

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

    OpenAIRE

    Chen, Chien Chon

    2013-01-01

    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 col...

  2. NaBi(WO4)2 - new scintillation monocrystals for electromagnetic calorimeters

    International Nuclear Information System (INIS)

    Baryshevskij, V.G.; Zadneprovskij, B.A.; Korzhik, M.V.

    1992-01-01

    Selection of materials for complete absorption electromagnetic calorimeters is one of the most actual problems related to the development and constuction of colliders. It is established that NaBi(WO 4 ) 2 crystals are promising in terms of their application in electromagnetic calorimeters and can successfully replace lead glass. NaBi(WO 4 ) 2 crystals, 20x20x110(11X 0 ) mm, were tested at the Serpukhov accelerator when recording 26 GeV electrons. Energy resolution was 1.4 %

  3. Improvement of radiopurity level of enriched {sup 116}CdWO{sub 4} and ZnWO{sub 4} crystal scintillators by recrystallization

    Energy Technology Data Exchange (ETDEWEB)

    Barabash, A.S. [National Research Centre “Kurchatov Institute”, Institute of Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Belli, P. [INFN, sezione di Roma “Tor Vergata”, I-00133 Rome (Italy); Bernabei, R., E-mail: rita.bernabei@roma2.infn.it [INFN, sezione di Roma “Tor Vergata”, I-00133 Rome (Italy); Dipartimento di Fisica, Università di Roma “Tor Vergata”, I-00133 Rome (Italy); Borovlev, Yu.A. [Nikolaev Institute of Inorganic Chemistry, 630090 Novosibirsk (Russian Federation); Cappella, F.; Caracciolo, V.; Cerulli, R. [INFN, Laboratori Nazionali del Gran Sasso, I-67100 Assergi (AQ) (Italy); Danevich, F.A. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Incicchitti, A. [INFN, sezione di Roma, I-00185 Rome (Italy); Dipartimento di Fisica, Università di Roma “La Sapienza”, I-00185 Rome (Italy); Kobychev, V.V. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Konovalov, S.I. [National Research Centre “Kurchatov Institute”, Institute of Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Laubenstein, M. [INFN, Laboratori Nazionali del Gran Sasso, I-67100 Assergi (AQ) (Italy); Mokina, V.M. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); INFN, sezione di Roma, I-00185 Rome (Italy); Polischuk, O.G. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Safonova, O.E. [V.S. Sobolev Institute of Geology and Mineralogy of the Siberian Branch of the RAS, 630090 Novosibirsk (Russian Federation); Shlegel, V.N. [Nikolaev Institute of Inorganic Chemistry, 630090 Novosibirsk (Russian Federation); and others

    2016-10-11

    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 {sup 116}CdWO{sub 4} crystal scintillator by thorium was reduced by a factor ≈10, down to the level 0.01 mBq/kg ({sup 228}Th), 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 {sup 228}Th) was observed in a sample of ZnWO{sub 4} crystal produced by recrystallization after removing ≈0.4 mm surface layer of the crystal.

  4. Osmotic-induced phase inversion of multiple W/O/W into a W/O emulsion: rheological study of an inverted W/O emulsion

    International Nuclear Information System (INIS)

    Fredro-Kumbaradzi, Emilija; Simov, Angel; Popovska-Pavlovska, Frederika

    1995-01-01

    Osmotic induced phase inversion of a W/O/W emulsion due to the presence of NaCl in the internal aqueous phase is discussed in this paper. Visco metric measurements of the obtained W/O emulsion were also carried out in order to determine its rheological properties as well as its stability during storage. Pseudo plastic flow and negative thixotropy behavior were observed under different shearing conditions. Negative thixotropy behavior, which is most likely a result of emulsion dispersion status changes, increased with increased program time, holding time at the maximum shear rate, and max. shear rate, but decreased with repeated time of shear. Changes in the flow curves under different shear conditions were not very significant. Also, no significant changes in the rheological behavior were noticed during four weeks storage of the inverted emulsion samples at room temperature. Thus, the inverted emulsion of a W/O type is a relatively stable system. (Author)

  5. Numerical model of the catchments of the oziąbel and wołczyński strumień rivers - Wołczyn municipality

    Science.gov (United States)

    Olichwer, Tomasz; Wcisło, Marek; Staśko, Stanisław; Buczyński, Sebastian; Modelska, Magdalena; Tarka, Robert

    2012-10-01

    The article presents a numerical model designed for determining groundwater dynamics and water balance of the catchments of the Oziąbel (Czarna Woda) river and the Wołczyński Strumień river in Wołczyn region. Hydrogeological mapping and modelling research covered the area of 238.9 km2. As a result of measurements performed in 2008-2009, flows were determined in major rivers and water table positions were measured at 26 points. In the major part of the area described, the water table, lying at the depth of 1.5-18.7 m, has unconfined character, and the aquifer is built of Neogene (Quaternary) sands and gravels. In the area under study, groundwaters are drawn from 6 wells with total withdrawal of 6133 m3/d. The numerical modelling was performed with the use of Visual Modflow 3.1.0 software. The area was partitioned by a discretization grid with a step size l = 250 m. The conceptual model of the hydrogeological system is based on hydrological data gathered over a period of one year, data from HYDRO bank database, cross-sections and maps. The boundaries of the modelled hydrogeological system were established on the watersheds of the Wołczyński Strumień river and the Oziąbel river, apart from the areas where they run together. The modelled area was extended (271.5 km2) around the Wołczyński Strumień river catchment to achieve a more effective mapping of the anthropogenic impact on its balance and the hydrodynamic system of the catchment area. The structure is characterised by the occurrence of one or rarely two aquifers separated by a pack of Quaternary clays. The investigation produced a detailed water balance and its components.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chávez, F., E-mail: f_perez_s@hotmail.com [Department of Physical-Chemical Materials, ICUAP-BUAP, 72000, Puebla (Mexico); Pérez-Sánchez, G.F. [Department of Physical-Chemical Materials, ICUAP-BUAP, 72000, Puebla (Mexico); Goiz, O. [Department of Electrical Engineering, CINVESTAV-IPN, 07360, México, D.F (Mexico); Zaca-Morán, P. [Department of Physical-Chemical Materials, ICUAP-BUAP, 72000, Puebla (Mexico); Peña-Sierra, R.; Morales-Acevedo, A. [Department of Electrical Engineering, CINVESTAV-IPN, 07360, México, D.F (Mexico); Felipe, C. [Department of Biosciences and Engineering, CIIEMAD-IPN, 07340, México, D.F (Mexico); Soledad-Priego, M. [Faculty of Electronics Sciences, FCE, 72000, Puebla (Mexico)

    2013-06-15

    In this work, we show a simple way to functionalize tungsten oxide nanowires (WO{sub 3}-NWs) using a saturated palladium chloride (PdCl{sub 2}) solution deposited by a drop-casting method. WO{sub 3}-NWs were synthesized by close-spaced chemical vapor deposition (CSVT). The morphological and structural characterizations showed that the diameters of WO{sub 3}-NWs are in the range from 50 to 200 nm with lengths above 10 μm, and correspond to the orthorhombic phase of WO{sub 3}, respectively. The sensor was fabricated using the WO{sub 3}-NWs and tested with hydrogen and volatile organic compounds (VCO's). A comparative study was done on the sensing performance, before and after the Palladium functionalization of the WO{sub 3}-NWs, considering a wide range of gas concentrations and moderate operating temperatures (100–400 °C). The results show that this simple functionalization process significantly increases the sensor sensitivity and reduces the time constants. In addition, it has been shown that at 300 °C the decorated sensor becomes more selective to hydrogen and xylene for all concentrations considered in this research. Finally, the mechanisms involved in improving the gas sensing properties of WO{sub 3}-NWs functionalized with Palladium are discussed.

  7. Microwave selective heating for size effect of water droplet in W/O emulsion with sorbitan fatty acid monostearate surfactant

    International Nuclear Information System (INIS)

    Sumi, Takuya; Horikoshi, Satoshi

    2015-01-01

    A stable water/oil (W/O) emulsion was prepared by adjustment with sorbitan fatty acid monoester surfactants. The prepared W/O emulsion was stable for 60 min in the atmosphere; however, the formation of non-uniform water droplets in the height of the emulsion in the quartz tube reactor were observed by the backscattering measurements with an infrared laser at 850 nm. The increase of temperature under microwave irradiation was influenced sensitively by the position of those water droplets. Those results were caused from the size and concentration of water droplets in the W/O emulsion. On the other hand, selective heating of the water droplets caused heating of the entire W/O emulsion, although the temperature difference between the water droplets and the oil phase was 20 °C. - Graphical abstract: The feature of a selective heating phenomenon in a W/O emulsion under microwave irradiation was investigated both practically and theoretically. Temperature profiles of emulsions stabilized with different sorbitan fatty acid monoester surfactants indicated that a smaller size distribution of water droplets leads to a higher heating rate. Moreover, computational studies suggested that water droplets in oil are 20 °C higher than the organic phase. - Highlights: • The microscopic heating features of microwaves in a W/O emulsion were examined. • The microwave heating behaviors reflected the properties of water droplets. • The heat convection process in a W/O emulsion was studied by a theoretical approach

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

    Science.gov (United States)

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

    2017-05-01

    A new kind of hierarchical Pd-Bi2WO6 architecture decorated with different molar ratios of Pd to Bi, has been fabricated by a hydrothermal process, followed by a chemical deposition method. The photocatalytic activities of the pure Bi2WO6 and Pd-Bi2WO6 nanocatalyst were examined in the degradation of Rhodamine B (RhB) dyes and phenol under visible light. The photocatalytic results showed that the Pd-Bi2WO6 nanocomposites possessed observably enhanced photocatalytic activities. Particularly, the 2.0% Pd loaded Bi2WO6 had the highest photocatalytic activity, exhibiting a nearly complete degradation of 30 mg/L RhB and 10 mg/L phenol within only 50 and 60 min, respectively. In addition, the trapping experiment results indicated that the photo-generated holes (h+) and rad O2- played a crucial role in the degradation of RhB. According to the experimental results, the photocatalytic degradation mechanism of Pd-Bi2WO6 was also proposed. The enhanced photocatalytic activities were ascribed to the combined effects of the highly efficient separation of electrons and holes, improved visible light utilization and increased BET specific surface areas of the Pd-Bi2WO6 nanocomposites.

  9. Ag loaded WO{sub 3} nanoplates for efficient photocatalytic degradation of sulfanilamide and their bactericidal effect under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wenyu [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141 (Singapore); Liu, Jincheng, E-mail: JCLIU@ntu.edu.sg [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Current address: Faculty of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510009 (China); Yu, Shuyan; Zhou, Yan [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141 (Singapore); Yan, Xiaoli, E-mail: XLYAN@ntu.edu.sg [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Current address: Environmental and Water Technology Centre of Innovation, Ngee Ann Polytechnic, 535 Clementi Road, Singapore 599489 (Singapore)

    2016-11-15

    Highlights: • WO{sub 3}/Ag heterogeneous composites were fabricated with simply photo-reduction method. • Property changes due to Ag loading were systematically studied. • WO{sub 3}/Ag composites efficiently degraded sulfanilamide under visible light irradiation. • WO{sub 3}/Ag composites exhibited bactericidal effectS under visible light irradiation. - Abstract: Sulfonamides (SAs) are extensively used antibiotics and their residues in the water bodies propose potential threat to the public. In this study, degradation efficiency of sulfanilamide (SAM), which is the precursor of SAs, using WO{sub 3} nanoplates and their Ag heterogeneous as photocatalysts was investigated. WO{sub 3} nanoplates with uniform size were synthesized by a facile one step hydrothermal method. Different amount of Ag nanoparticles (Ag NPs) were loaded onto WO{sub 3} nanoplates using a photo-reduction method to generate WO{sub 3}/Ag composites. The physio-chemical properties of synthesized nanomaterials were systematically characterized. Photodegradation of SAM by WO{sub 3} and WO{sub 3}/Ag composites was conducted under visible light irradiation. The results show that WO{sub 3}/Ag composites performed much better than pure WO{sub 3} where the highest removal rate was 96.2% in 5 h. Ag as excellent antibacterial agent also endows certain antibacterial efficiency to WO{sub 3}, and 100% removal efficiency against Escherichia Coli and Bacillus subtilis could be achieved in 2 h under visible light irradiation for all three WO{sub 3}/Ag composites synthesized. The improved performance in terms of SAM degradation and antibacterial activity of WO{sub 3}/Ag can be attributed to the improved electron-hole pair separation rate where Ag NPs act as effective electron trapper during the photocatalytic process.

  10. WO3/Conducting Polymer Heterojunction Photoanodes for Efficient and Stable Photoelectrochemical Water Splitting.

    Science.gov (United States)

    Jeon, Dasom; Kim, Nayeong; Bae, Sanghyun; Han, Yujin; Ryu, Jungki

    2018-02-26

    An efficient and stable heterojunction photoanode for solar water oxidation was fabricated by hybridization of WO 3 and conducting polymers (CPs). Organic/inorganic hybrid photoanodes were readily prepared by the electropolymerization of various CPs and the codeposition of tetraruthenium polyoxometalate (Ru 4 POM) water-oxidation catalysts (WOCs) on the surface of WO 3 . The deposition of CPs, especially polypyrrole (PPy) doped with Ru 4 POM (PPy:Ru 4 POM), resulted in a remarkably improved photoelectrochemical performance by the formation of a WO 3 /PPy p-n heterojunction and the incorporation of efficient Ru 4 POM WOCs. In addition, there was also a significant improvement in the photostability of the WO 3 -based photoanode after the deposition of the PPy:Ru 4 POM layer due to the suppression of the formation of hydrogen peroxide, which was responsible for corrosion. This study provides insight into the design and fabrication of novel photosynthetic and photocatalytic systems with excellent performance and stability through the hybridization of organic and inorganic materials.

  11. Highly Yb-doped KGd(WO4)2 thin-film amplifier

    NARCIS (Netherlands)

    Yong, Yean Sheng; Aravazhi, S.; Vázquez-Córdova, Sergio Andrés; García Blanco, Sonia Maria; Pollnau, Markus

    We report record-high small-signal gain of 1050 dB/cm at 981 nm wavelength in a KGd0.425Yb0.575(WO4)2 thin film. The sensitivity of gain to the shift of beam-focus position, which is critical under non-waveguiding conditions, is investigated.

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

    NARCIS (Netherlands)

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

    2010-01-01

    By resistively heating tungsten filaments in a constant air flow under a reduced pressure, nanogranular amorphous WO3 thin films are deposited on glassy carbon substrates. The substrate surface temperature is monitored by a thermocouple. For deposition times of 15 min and longer, the films show

  13. Structural and functional properties of nanocomposite Au–WO3 coatings

    NARCIS (Netherlands)

    Figueiredo, N.M.; Pei, Yutao T.; De Hosson, J.T.M.; Cavaleiro, A.

    2015-01-01

    In this study several Au–WO3 nanocomposite coatings were deposited by reactive magnetron co-sputtering and characterized with respect to their chemical composition, structure, microstructure and mechanical and optical properties. The nanocomposites consist of a dual phase system of Au nanoparticles

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

    Energy Technology Data Exchange (ETDEWEB)

    Amaechi, C.I.; Asogwa, P.U.; Ekwealor, A.B.C. [University of Nigeria, Department of Physics and Astronomy, Nsukka, Enugu State (Nigeria); Osuji, R.U.; Ezema, F.I. [University of Nigeria, Department of Physics and Astronomy, Nsukka, Enugu State (Nigeria); iThemba LABS-National Research Foundation, Nanosciences African Network (NANOAFNET), Somerset West, Western Cape Province (South Africa); University of South Africa (UNISA), UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, Pretoria (South Africa); Maaza, M. [iThemba LABS-National Research Foundation, Nanosciences African Network (NANOAFNET), Somerset West, Western Cape Province (South Africa); University of South Africa (UNISA), UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, Pretoria (South Africa)

    2014-11-15

    A nanocrystalline and porous p-polyaniline/n-WO{sub 3} dissimilar heterojunction at ambient temperature is reported. The high-quality and well-reproducible conjugated polymer composite films have been fabricated by oxidative polymerization of anilinium ion on predeposited WO{sub 3} thin film by chemical bath deposition followed by thermal annealing at 573 K for 1 h. Atomic force microscopy (AFM) analyses reveal a homogenous but irregular cluster of faceted spherically shaped grains with pores. The scanning electron microscopy confirms the porous network of grains, which is in good agreement with the AFM result. The optical absorption analysis of polyaniline/WO{sub 3} hybrid films showed that direct optical transition exist in the photon energy range 3.50-4.00 eV with bandgap of 3.70 eV. The refractive index developed peak at 445 nm in the dispersion region while the high-frequency dielectric constant, ε {sub ∞}, and the carrier concentration to effective mass ratio, N/m{sup *}, was found to be 1.58 and 1.10 x 10{sup 39} cm{sup -3}, respectively. The temperature dependence of electrical resistivity of the deposited films follows the semiconductor behavior while the C-V characteristics (Mott-Schottky plots) show that the flat band potential was -791 and 830 meV/SCE for WO{sub 3} and polyaniline. (orig.)

  15. Luminescent properties of red-light-emitting phosphors CaWO4: Eu ...

    Indian Academy of Sciences (India)

    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' ...

  16. Luminescent properties of red-light-emitting phosphors CaWO 4

    Indian Academy of Sciences (India)

    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' ...

  17. An UV photochromic memory effect in proton-based WO3 electrochromic devices

    International Nuclear Information System (INIS)

    Zhang Yong; Lee, S.-H.; Mascarenhas, A.; Deb, S. K.

    2008-01-01

    We report an UV photochromic memory effect on a standard proton-based WO 3 electrochromic device. It exhibits two memory states, associated with the colored and bleached states of the device, respectively. Such an effect can be used to enhance device performance (increasing the dynamic range), re-energize commercial electrochromic devices, and develop memory devices

  18. An UV photochromic memory effect in proton-based WO3 electrochromic devices

    Science.gov (United States)

    Zhang, Yong; Lee, S.-H.; Mascarenhas, A.; Deb, S. K.

    2008-11-01

    We report an UV photochromic memory effect on a standard proton-based WO3 electrochromic device. It exhibits two memory states, associated with the colored and bleached states of the device, respectively. Such an effect can be used to enhance device performance (increasing the dynamic range), re-energize commercial electrochromic devices, and develop memory devices.

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

    NARCIS (Netherlands)

    Caruso, T.; Castriota, M.; Policicchio, A.; Fasanella, A.; Santo, M.P. De; Ciuchi, F.; Desiderio, G.; Rosa, S. La; Rudolf, P.; Agostino, R.G.; Cazzanelli, E.

    2014-01-01

    The electronic, morphological and structural properties of WO3 thin films, synthesized via a sol-gel route and deposited on ITO/glass substrates by spin-coating, were analyzed as a function of annealing temperature (100-700 degrees C range) by Scanning Electron Microscopy, Atomic Force Microscopy,

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

    Directory of Open Access Journals (Sweden)

    Chien Chon Chen

    2013-01-01

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

  1. Ethanol vapour sensing properties of screen printed WO 3 thick films

    Indian Academy of Sciences (India)

    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 ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Argelia Perez, E-mail: ekargy@hotmail.com [Universidad Nacional Autonoma de Mexico, Laboratorio de Fotofisica y Peliculas Delgadas-CCADET, Ciudad Universitaria, Coyoacan, A.P. 70-186, C.P. 04510, Mexico, D.F. (Mexico); Montes de Oca, C. Oliva; Castaneda-Guzman, R.; Garcia, A. Esparza [Universidad Nacional Autonoma de Mexico, Laboratorio de Fotofisica y Peliculas Delgadas-CCADET, Ciudad Universitaria, Coyoacan, A.P. 70-186, C.P. 04510, Mexico, D.F. (Mexico)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The phototransformation of WO{sub 3} thin films were studied by photoacoustic technique. Black-Right-Pointing-Pointer The phase transition in WO{sub 3} thin films was induced by laser irradiation fluence. Black-Right-Pointing-Pointer The onset and end of the phototransformation in the thin films was identified. Black-Right-Pointing-Pointer The ablation threshold for each sample was identified. - Abstract: The photoacoustic technique (PA) was used to detect the phase transformation from amorphous to crystalline state of tungsten oxide (WO{sub 3}) thin films induced by UV pulsed laser radiation at low energy (<1.5 mJ). The evolution of photoacoustic signal was studied by a correlation analysis, comparing successive signals at fluences ranging from 0 to 20 mJ/cm{sup 2}. In this interval, it was possible to observe structural changes and the ablation threshold in films due to incident laser fluence effect. Thin films of WO{sub 3} were deposited by DC reactive magnetron sputtering over glass substrates at different deposition times. The results obtained by correlation analysis were compared with Raman spectroscopy data.

  3. Synthesis and characterization of MoO3–WO3 composite thin films ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 36; Issue 1. Synthesis and characterization of MoO3–WO3 composite thin films by liquid phase deposition technique: Investigation of its photochromic properties. H M Farveez Ahmed Noor Shahina Begum. Volume 36 Issue 1 February 2013 pp 45-49 ...

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

    NARCIS (Netherlands)

    Batjes, N.H.; Carvalho Ribeiro, E.D.; Oostrum, van A.J.M.; Leenaars, J.G.B.; Hengl, T.; Mendes de Jesus, J.S.

    2017-01-01

    The aim of the World Soil Information Service (WoSIS) is to serve quality-assessed, georeferenced soil data (point, polygon, and grid) to the international community upon their standardisation and harmonisation. So far, the focus has been on developing procedures for legacy point data with special

  5. Alkali-Phosphate Glasses Containing WO3 and Nb2O5

    Directory of Open Access Journals (Sweden)

    L. Bih

    2013-01-01

    Full Text Available New phosphate glasses in the quaternary system (50-x A2O-x WO3-10 Nb2O5-40 P2O5, with x = 0; 30 and A = Li or Na were prepared by the melt quenching method. The effect on the crystallization behaviour of the glass due to the introduction of WO3 into the glass composition and, consequently, the diminishing of the molar amount of the alkaline oxide and the decreasing of the molar ratio between network modifiers and network formers (M/F was studied. The prepared glasses were heat-treated in air, at 550°C, 600°C, and 650°C for 4 hours. The structure, of the obtained samples, was studied by differential thermal analysis (DTA, X-ray powder diffraction (XRD, and Raman spectroscopy and the morphology by scanning electron microscopy (SEM. It was found that the replacement of Li2O or Na2O by WO3 reduces the number of the crystallised phases. In the lithium-niobiophosphate glasses, the presence of WO3 promotes the formation of NbOPO4 instead of the LiNbO3 phase and reduces the formation of ortho- and pyro-phosphate phases. The thermal treatments affect the arrangements of the network structure of the AW40-glasses.

  6. Characteristics of W/O emulsions containing polymeric emulsifier PEG 30-dipolyhydroxystearate

    Directory of Open Access Journals (Sweden)

    Milinković Jelena R.

    2016-01-01

    Full Text Available Water-in-oil (W/O emulsions are dispersed systems which are often used in the pharmaceutical, cosmetic and food industries as products, or as carriers of active substances. It is well known that they are very unstable, so that selection of the emulsifier and properties of the oil and water phase are main factors affecting their stability. The aim of this paper was to examine the possibility of application of a lipophilic, polymeric emulsifier, PEG 30-dipolyhydroxystearate (CithrolTM DPHS, for stabilization of W/O emulsions. Behaviour of the emulsifier at W/O interfaces was determined by means of tensiometry. A series of emulsions were prepared with 20% (w/w of water and different types of oil. Droplet size, droplet size distribution, viscosity, and sedimentation stability during 30 days of storage at room temperature of the emulsions prepared with paraffin oil, olive oil, grape seed oil, and medium-chain triglycerides, stabilized with 1% CithrolTM DPHS, were determined. All investigated emulsions were stable for 30 days, except the one prepared with paraffin oil. The results of this study confirmed that PEG 30-dipolyhydroxylstearate is a good emulsifier and stabilizer of W/O emulsions which contain different types of oil. [Projekat Ministarstva nauke Republike Srbije, br. III46010

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

    Science.gov (United States)

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

    2016-07-01

    Ultrasmall biocompatible WO3 - x nanodots with an outstanding X-ray radiation sensitization effect are prepared, and demonstrated to be applicable for multi-modality tumor imaging through computed tomography and photoacoustic imaging (PAI), and effective cancer treatment combining both photothermal therapy and radiation therapy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Electrical and optical properties of ZnO–WO3 nanocomposite and its ...

    Indian Academy of Sciences (India)

    DOI 10.1007/s12034-017-1373-5. Electrical and optical properties of ZnO–WO3 nanocomposite and its application as a solid-state humidity sensor. VANDNA SHAKYA. ∗. , N K PANDEY, SUNEET KUMAR MISRA and AKASH ROY. Sensors and Materials Research Laboratory, Department of Physics, University of Lucknow, ...

  9. Electrochromism and photocatalysis in dendrite structured Ti:WO3 thin films grown by sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Karuppasamy, A., E-mail: karuppasamy@psnacet.edu.in

    2015-12-30

    Graphical abstract: - Highlights: • Dendrite structured Ti doped WO{sub 3} (WTO) thin films are grown by co-sputtering. • Sputtering condition influences structure and surface morphology of WTO films. • Titanium doping and annealing lead to dendritic surface structures in WTO films. • Structural, optical, electrochromic and photocatalytic properties of WTO films. • Enhanced electrochromism and photocatalysis in dendrite structured WTO thin films. - Abstract: Titanium doped tungsten oxide (Ti:WO{sub 3}) thin films with dendrite surface structures were grown by co-sputtering titanium and tungsten in Ar + O{sub 2} atmosphere. Ti:WO{sub 3} thin films were deposited at oxygen flow rates corresponding to pressures in the range 1.0 × 10{sup −3}–5.0 × 10{sup −3} mbar. Argon flow rate and sputtering power densities for titanium (2 W/cm{sup 2}) and tungsten (3 W/cm{sup 2}) were kept constant. Ti:WO{sub 3} films deposited at an oxygen pressure of 5 × 10{sup −3} mbar are found to be better electrochromic and photocatalytic. They have high optical modulation (80% at λ = 550 nm), coloration efficiency (60 cm{sup 2}/C at λ = 550 nm), electron/ion storage and removal capacity (Qc: −22.01 mC/cm{sup 2}, Qa: 17.72 mC/cm{sup 2}), reversibility (80%) and methylene blue decomposition rate (−1.38 μmol/l d). The combined effects of titanium doping, dendrite surface structures and porosity leads to significant enhancement in the electrochromic and photocatalytic properties of Ti:WO{sub 3} films.

  10. Electrochromism and photocatalysis in dendrite structured Ti:WO3 thin films grown by sputtering

    International Nuclear Information System (INIS)

    Karuppasamy, A.

    2015-01-01

    Graphical abstract: - Highlights: • Dendrite structured Ti doped WO 3 (WTO) thin films are grown by co-sputtering. • Sputtering condition influences structure and surface morphology of WTO films. • Titanium doping and annealing lead to dendritic surface structures in WTO films. • Structural, optical, electrochromic and photocatalytic properties of WTO films. • Enhanced electrochromism and photocatalysis in dendrite structured WTO thin films. - Abstract: Titanium doped tungsten oxide (Ti:WO 3 ) thin films with dendrite surface structures were grown by co-sputtering titanium and tungsten in Ar + O 2 atmosphere. Ti:WO 3 thin films were deposited at oxygen flow rates corresponding to pressures in the range 1.0 × 10 −3 –5.0 × 10 −3 mbar. Argon flow rate and sputtering power densities for titanium (2 W/cm 2 ) and tungsten (3 W/cm 2 ) were kept constant. Ti:WO 3 films deposited at an oxygen pressure of 5 × 10 −3 mbar are found to be better electrochromic and photocatalytic. They have high optical modulation (80% at λ = 550 nm), coloration efficiency (60 cm 2 /C at λ = 550 nm), electron/ion storage and removal capacity (Qc: −22.01 mC/cm 2 , Qa: 17.72 mC/cm 2 ), reversibility (80%) and methylene blue decomposition rate (−1.38 μmol/l d). The combined effects of titanium doping, dendrite surface structures and porosity leads to significant enhancement in the electrochromic and photocatalytic properties of Ti:WO 3 films.

  11. CTAB-Assisted Hydrothermal Synthesis of WO3 Hierarchical Porous Structures and Investigation of Their Sensing Properties

    Directory of Open Access Journals (Sweden)

    Dan Meng

    2015-01-01

    Full Text Available WO3 hierarchical porous structures were successfully synthesized via cetyltrimethylammonium bromide- (CTAB- assisted hydrothermal method. The structure and morphology were investigated using scanning electron microscope, X-ray diffractometer, transmission electron microscopy, X-ray photoelectron spectra, Brunauer-Emmett-Teller nitrogen adsorption-desorption, and thermogravimetry and differential thermal analysis. The result demonstrated that WO3 hierarchical porous structures with an orthorhombic structure were constructed by a number of nanoparticles about 50–100 nm in diameters. The H2 gas sensing measurements showed that well-defined WO3 hierarchical porous structures with a large specific surface area exhibited the higher sensitivity compared with products without CTAB at all operating temperatures. Moreover, the reversible and fast response to H2 gas and good selectivity were obtained. The results indicated that the WO3 hierarchical porous structures are promising materials for gas sensors.

  12. Mesoporous nanoplate multi-directional assembled Bi2WO6for high efficient photocatalytic oxidation of NO.

    Science.gov (United States)

    Wan, Jun; Du, Xiao; Wang, Ruimiao; Liu, Enzhou; Jia, Jia; Bai, Xue; Hu, Xiaoyun; Fan, Jun

    2018-02-01

    Herein, a mesoporous nanoplate multi-directional assembled Bi 2 WO 6 architecture was successfully prepared and applied for the photocatalytic removal of NOx pollutants at low concentrations under visible light and simulated solar light irradiation. Bi 2 WO 6 -180-C synthesized at a hydrothermal temperature of 180 °C with calcination exhibited an excellent conversion efficiency in the photocatalytic oxidation of gaseous NO. The crystallinity, morphology, specific surface area, pore environment, light absorption, and separation of photogenerated electrons and holes were investigated by various techniques; the excellent photocatalytic performance of Bi 2 WO 6 -180-C was attributed to its special hierarchical mesoporous structure with an appropriate pore size and interconnected porous network, which imparted good gas permeability and fast mass transfer of reaction intermediates and final products of NO oxidation. Furthermore, hierarchical mesoporous Bi 2 WO 6 showed excellent photocatalytic durability and reusability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Pronounced effects of the nominal concentrations of WO3 and Ag: WO3 nano-plates (obtained by a co-precipitation method) on their structural, morphological and optical properties

    Science.gov (United States)

    Rajendran, V.; Deepa, B.

    2018-03-01

    Tungsten oxide and different concentration of silver (Ag)-doped tungsten oxide nano material were synthesized by co-precipitation technique. The functional vibrations, structure, and morphology of as-prepared nano material were studied by Fourier transmission infrared spectroscopy, X-ray diffraction, scanning electron microscopy (SEM) and High-resolution transmission electron microscopy (HR-TEM) techniques. The SEM and HR-TEM analysis revealed the formation of nano-plate/nano rods with an average diameter of 40-80 nm diameter and 1-1.5 mm length. Fluorescence (PL) and UV-visible absorption techniques have been used to study the optical properties of the prepared nanoparticles. The observed red shift in the visible absorption spectra confirmed the promoted electron-phonon interaction in WO3 and Ag: WO3 nanoparticles compared to bulk structures. The photoluminescence of nanocrystalline Ag2+ doped WO3 exhibited a strong violet-blue, blue-green emission. Concentration dependence of the emission intensity of Ag2+ in WO3 was studied, and the significant concentration was found to be 0.5% of Ag: WO3. The effluent dye degradation executed for the 0.5% of Ag: WO3 sample under the visible light which reveals the highest degradation efficiency in appropriate time.

  14. Solar photocatalytic activity of TiO2 modified with WO3 on the degradation of an organophosphorus pesticide

    International Nuclear Information System (INIS)

    Ramos-Delgado, N.A.; Gracia-Pinilla, M.A.; Maya-Treviño, L.; Hinojosa-Reyes, L.; Guzman-Mar, J.L.; Hernández-Ramírez, A.

    2013-01-01

    Highlights: • TiO 2 and WO 3 /TiO 2 (2 and 5%) were tested in the photocatalytic malathion degradation. • The use of solar radiation in the photocatalytic degradation process was evaluated. • Modified catalyst showed greater photocatalytic activity than pure TiO 2 . • The mineralization rate was improved when WO 3 content on TiO 2 was 2%. -- Abstract: In this study, the solar photocatalytic activity (SPA) of WO 3 /TiO 2 photocatalysts synthesized by the sol–gel method with two different percentages of WO 3 (2 and 5%wt) was evaluated using malathion as a model contaminant. For comparative purpose bare TiO 2 was also prepared by sol–gel process. The powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, diffuse reflectance UV–vis spectroscopy (DRUV–vis), specific surface area by the BET method (SSA BET ), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy with a high annular angle dark field detector (STEM-HAADF). The XRD, Raman, HRTEM and STEM-HAADF analyses indicated that WO 3 was present as a monoclinic crystalline phase with nanometric cluster sizes (1.1 ± 0.1 nm for 2% WO 3 /TiO 2 and 1.35 ± 0.3 nm for 5% WO 3 /TiO 2 ) and uniformly dispersed on the surface of TiO 2 . The particle size of the materials was 19.4 ± 3.3 nm and 25.6 ± 3 nm for 2% and 5% WO 3 /TiO 2 , respectively. The SPA was evaluated on the degradation of commercial malathion pesticide using natural solar light. The 2% WO 3 /TiO 2 photocatalyst exhibited the best photocatalytic activity achieving 76% of total organic carbon (TOC) abatement after 300 min compared to the 5% WO 3 /TiO 2 and bare TiO 2 photocatalysts, which achieved 28 and 47% mineralization, respectively. Finally, experiments were performed to assess 2% WO 3 /TiO 2 catalyst activity on repeated uses; after several successive cycles its photocatalytic activity was retained showing long-term stability

  15. Mesoporous WN/WO3-Composite Nanosheets for the Chemiresistive Detection of NO2 at Room Temperature

    OpenAIRE

    Fengdong Qu; Bo He; Rohiverth Guarecuco; Minghui Yang

    2016-01-01

    Composite materials, which can optimally use the advantages of different materials, have been studied extensively. Herein, hybrid tungsten nitride and oxide (WN/WO3) composites were prepared through a simple aqueous solution route followed by nitriding in NH3, for application as novel sensing materials. We found that the introduction of WN can improve the electrical properties of the composites, thus improving the gas sensing properties of the composites when compared with bare WO3. The highe...

  16. Enhanced photocatalytic activity of Bi2WO6/TiO2 composite coated polyester fabric under visible light irradiation

    Science.gov (United States)

    Du, Zoufei; Cheng, Cheng; Tan, Lin; Lan, Jianwu; Jiang, Shouxiang; Zhao, Ludan; Guo, Ronghui

    2018-03-01

    In this study, a visible-light-driven photocatalyst Bi2WO6/TiO2 composite was reported using one-step hydrothermal method and then coated on the polyester fabric. The samples were systematically characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, UV-vis diffuse reflection spectroscopy and photoluminescence spectroscopy (PL). The photocatalytic activity of Bi2WO6/TiO2 coated polyester fabric was evaluated by degradation of Rhodamine B (RhB) and Methylene blue (MB) under visible light irradiation. The self-cleaning property of the fabrics was assessed through removing red wine stain. The results reveal that the Bi2WO6/TiO2 composites with irregular shape are coated on the polyester fabric successfully. The UV-vis absorption spectra show a broad absorption band in the visible region, which extends the scope of absorption spectrum and helps to improve the photocatalytic degradation efficiency. Photocatalytic activities of the Bi2WO6/TiO2 composite polyester fabric are associated with the content of TiO2. Bi2WO6/15%TiO2 coated polyester fabric exhibits the degradation efficiency for RhB and MB up to 98% and 95.1%, respectively, which is much higher than that of pure Bi2WO6 and TiO2 coated polyester fabric. Moreover, Bi2WO6/15%TiO2 coated polyester fabric shows good cycle stability toward continuous three cycles of photocatalytic experiment for dyes degradation. In addition, the Bi2WO6/TiO2 coated polyester fabric shows good self-cleaning property. This work could be extended to design of other composite photocatalyst coating on the fabric for enhancing activity by coupling suitable wide and narrow band-gap semiconductors.

  17. Synthesis of WO3 nanoparticles by citric acid-assisted precipitation and evaluation of their photocatalytic properties

    International Nuclear Information System (INIS)

    Sánchez-Martínez, D.; Martínez-de la Cruz, A.; López-Cuéllar, E.

    2013-01-01

    Graphical abstract: Display Omitted Highlights: ► WO 3 nanoparticles were synthesized by a simple citric acid-assisted precipitation. ► WO 3 photocatalyst was able to the partial mineralization of rhB, IC and MO. ► WO 3 can be considered as a photocatalyst active under visible light irradiation. -- Abstract: WO 3 nanoparticles were synthesized by citric acid-assisted precipitation method using a 1:1.5 molar ratio of ammonium paratungstate hydrate (H 42 N 10 O 42 W 12 ·xH 2 O):citric acid (C 6 H 8 O 7 ). The formation of monoclinic crystal structure of WO 3 at different temperatures was confirmed by X-ray powder diffraction (XRD). The characterization of the samples synthesized was complemented by transmission electron microscopy (TEM), Brunauer–Emmitt–Teller surface area (BET) and diffuse reflectance spectroscopy (DRS). According to the thermal treatment followed during the synthesis of WO 3 , the morphology of the nanoparticles formed was characterized by rectangular and ovoid shapes. The photocatalytic activity of WO 3 obtained under different experimental conditions was evaluated in the degradation of rhodamine B (rhB), indigo carmine (IC), methyl orange (MO), and Congo red (CR) in aqueous solution under UV and UV–vis radiation. The highest photocatalytic activity was observed in the sample obtained by thermal treatment at 700 °C. In general, the sequence of degradation of the organic dyes was: indigo carmine (IC) > rhodamine B (rhB) > methyl orange (MO) > Congo red (CR). The mineralization degree of organic dyes by WO 3 photocatalysts was determined by total organic carbon analysis (TOC) reaching percentages of mineralization of 82% (rhB), 85% (IC), 28% (MO), and 7% (CR) for 96 h of lamp irradiation.

  18. Synthesis of WO{sub 3} nanoparticles by citric acid-assisted precipitation and evaluation of their photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Martínez, D. [Departamento de Ecomateriales y Energía, Facultad de Ingeniería Civil (UANL), Ciudad Universitaria, C.P. 66451, San Nicolás de los Garza, N.L. (Mexico); Martínez-de la Cruz, A., E-mail: azael70@yahoo.com.mx [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451, San Nicolás de los Garza, N.L. (Mexico); López-Cuéllar, E. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451, San Nicolás de los Garza, N.L. (Mexico)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► WO{sub 3} nanoparticles were synthesized by a simple citric acid-assisted precipitation. ► WO{sub 3} photocatalyst was able to the partial mineralization of rhB, IC and MO. ► WO{sub 3} can be considered as a photocatalyst active under visible light irradiation. -- Abstract: WO{sub 3} nanoparticles were synthesized by citric acid-assisted precipitation method using a 1:1.5 molar ratio of ammonium paratungstate hydrate (H{sub 42}N{sub 10}O{sub 42}W{sub 12}·xH{sub 2}O):citric acid (C{sub 6}H{sub 8}O{sub 7}). The formation of monoclinic crystal structure of WO{sub 3} at different temperatures was confirmed by X-ray powder diffraction (XRD). The characterization of the samples synthesized was complemented by transmission electron microscopy (TEM), Brunauer–Emmitt–Teller surface area (BET) and diffuse reflectance spectroscopy (DRS). According to the thermal treatment followed during the synthesis of WO{sub 3}, the morphology of the nanoparticles formed was characterized by rectangular and ovoid shapes. The photocatalytic activity of WO{sub 3} obtained under different experimental conditions was evaluated in the degradation of rhodamine B (rhB), indigo carmine (IC), methyl orange (MO), and Congo red (CR) in aqueous solution under UV and UV–vis radiation. The highest photocatalytic activity was observed in the sample obtained by thermal treatment at 700 °C. In general, the sequence of degradation of the organic dyes was: indigo carmine (IC) > rhodamine B (rhB) > methyl orange (MO) > Congo red (CR). The mineralization degree of organic dyes by WO{sub 3} photocatalysts was determined by total organic carbon analysis (TOC) reaching percentages of mineralization of 82% (rhB), 85% (IC), 28% (MO), and 7% (CR) for 96 h of lamp irradiation.

  19. Radiation Damage Mechanism in PbWO4 Crystal and Radiation Hardness Quality Control of PWO Scintillators for CMS

    CERN Document Server

    Baccaro, Stefania; Borgia, Bruno; Cavallari, Francesca; Cecilia, Angelica; Dafinei, Ioan; Diemoz, Marcella; Lecoq, Paul; Longo, Egidio; Montecchi, Marco; Organtini, Giovanni; Salvatori, S

    1997-01-01

    The optical damage induced by UV light in PbWO4 crystals is found to be similar to that induced by g radiation. Due to the peculiarities of optical absorption in PbWO4, the damage induced by UV light is a bulk process. This fact has important consequences for the approach to be adopted both for the use of the crystal as scintillator and for the qualification methods foreseen in the Regional Centres of the ECAL CMS Collaboration.

  20. Photoreduction of non-noble metal Bi on the surface of Bi{sub 2}WO{sub 6} for enhanced visible light photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaojing [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, No. 8, Xindu Road, Xindu District, Chengdu 610500 (China); The Center of New Energy Materials and Technology, School of Materials Science and Engineering, Southwest Petroleum University, No. 8, Xindu Road, Xindu District, Chengdu 610500 (China); Yu, Shan; Liu, Yang; Zhang, Qian [The Center of New Energy Materials and Technology, School of Materials Science and Engineering, Southwest Petroleum University, No. 8, Xindu Road, Xindu District, Chengdu 610500 (China); Zhou, Ying, E-mail: yzhou@swpu.edu.cn [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, No. 8, Xindu Road, Xindu District, Chengdu 610500 (China); The Center of New Energy Materials and Technology, School of Materials Science and Engineering, Southwest Petroleum University, No. 8, Xindu Road, Xindu District, Chengdu 610500 (China)

    2017-02-28

    Highlights: • Bi{sub 2}WO{sub 6}-Bi composite was synthesized by in situ photoreduction of Bi{sub 2}WO{sub 6}. • Bi{sub 2}WO{sub 6}-Bi exhibits improved photocatalytic efficiency towards degradation of Rhodamine B. • The generation of elemental Bi in Bi{sub 2}WO{sub 6}-Bi induces vacancy and structure distortion of Bi{sub 2}WO{sub 6}. • The surface oxygen adsorption mode changes from hydroxyl group on Bi{sub 2}WO{sub 6} to molecular oxygen on Bi{sub 2}WO{sub 6}-Bi. - Abstract: In this report, Bi{sub 2}WO{sub 6}-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 Bi{sub 2}WO{sub 6}-Bi maintains the same crystal structure with the pristine Bi{sub 2}WO{sub 6} regardless of some surface defects. Nevertheless, these surface defects result in the change of surface oxygen adsorption mode from hydroxyl to molecular oxygen on Bi{sub 2}WO{sub 6}. Photocatalytic activity over Bi{sub 2}WO{sub 6}-Bi is 2.4 times higher than that of Bi{sub 2}WO{sub 6} 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 Bi{sub 2}WO{sub 6}, but both the benzene cleavage and de-ethylation pathway coexist for RhB decomposition in the presence of Bi{sub 2}WO{sub 6}-Bi as the photocatalyst. Photoelectrochemical study including transient photocurrent tests and electrochemical impedance spectroscopy measurements shows that Bi{sub 2}WO{sub 6}-Bi could facilitate the charge transfer process compared to Bi{sub 2}WO{sub 6}. These data above has indicated a new insight into the promotion mechanism based on Bi related heterostructures.

  1. Effect of Post-annealing on the Electrochromic Properties of Layer-by-Layer Arrangement FTO-WO3-Ag-WO3-Ag

    Science.gov (United States)

    Hoseinzadeh, S.; Ghasemiasl, R.; Bahari, A.; Ramezani, A. H.

    2018-03-01

    In the current study, composites of tungsten trioxide (W03) and silver (Ag) are deposited in a layer-by-layer electrochromic (EC) arrangement onto a fluorine-doped tin oxide coated glass substrate. Tungsten oxide nanoparticles are an n-type semiconductor that can be used as EC cathode material. Nano-sized silver is a metal that can serve as an electron trap center that facilitates charge departure. In this method, the WO3 and Ag nanoparticle powder were deposited by physical vapor deposition onto the glass substrate. The fabricated electrochromic devices (ECD) were post-annealed to examine the effect of temperature on their EC properties. The morphology of the thin film was characterized by scanning electron microscopy and atomic force microscopy. Structural analysis showed that the addition of silver dopant increased the size of the aggregation of the film. The film had an average approximate roughness of about 17.8 nm. The electro-optical properties of the thin film were investigated using cyclic voltammetry and UV-visible spectroscopy to compare the effects of different post-annealing temperatures. The ECD showed that annealing at 200°C provided better conductivity (maximum current of about 90 mA in the oxidation state) and change of transmittance (ΔT = 90% at the continuous switching step) than did the other thin films. The optical band gaps of the thin film showed that it allowed direct transition at 3.85 eV. The EC properties of these combinations of coloration efficiency and response time indicate that the WO3-Ag-WO3-Ag arrangement is a promising candidate for use in such ECDs.

  2. Graphitic g-C{sub 3}N{sub 4}-WO{sub 3} Composite: Synthesis and Photocatalytic Properties

    Energy Technology Data Exchange (ETDEWEB)

    Doan, An Tran; Thi, Xuan Dieu Nguyen; Nguyen, Phi Hung; Thi, Viet Nga Nguyen; Vo, Vien [Quy Nhon Univ., Quy Nhon (Viet Nam); Kim, Sung Jin [Ewha Womans Univ., Seoul (Korea, Republic of)

    2014-06-15

    Graphitic g-C{sub 3}N{sub 4}-WO{sub 3} composite was synthesized simply by decomposing melamine in the presence of WO{sub 3} at 500 .deg. C. The obtained material was characterized by XRD, SEM, IR and XPS. The results showed that the as-prepared composite exhibits orthorhombic WO{sub 3} phase coated by g-C{sub 3}N{sub 4} and the g-C{sub 3}N{sub 4} decomposed completely with N-doped WO{sub 3} remaining at elevated calcination temperatures. The photocatalytic activity of the composite was evaluated by the photodegradation of methylene blue under visible light. An enhancement in photocatalytic activity for the graphitic g-C{sub 3}N{sub 4}-WO{sub 3} composite compared to the conventional nitrogen-doped WO{sub 3} was observed, which can be attributed to the presence of g-C{sub 3}N{sub 4} in the material.

  3. Subsolidus phase relations in the ZnO-WO{sub 3}-Bi{sub 2}O{sub 3} system

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yandi [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Chen Dagui, E-mail: chendg@fjirsm.ac.cn [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Pan Danmei; Tang Yuhuan; Liu Weizhen [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Huang Feng, E-mail: fhuang@fjirsm.ac.cn [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2011-01-12

    Research highlights: In order to search for suitable flux to grow ZnO single crystals, the subsolidus phase relations of the ternary system ZnO-WO{sub 3}-Bi{sub 2}O{sub 3} and the phase diagram of ZnO-Bi{sub 2}WO{sub 6} pseudo-binary system were investigated. The results reveal that the Bi{sub 2}WO{sub 6} might not be the suitable flux for ZnO crystal growth below 1250 deg. C. - Abstract: The subsolidus phase relations of the ternary system ZnO-WO{sub 3}-Bi{sub 2}O{sub 3} were investigated by means of X-ray diffraction (XRD). Six binary compounds and seven 3-phase regions were determined, and no ternary compounds were found in this ternary system. The phase diagram of pseudobinary system ZnO-Bi{sub 2}WO{sub 6} was also constructed through XRD and differential thermal analysis (DTA) methods, which forms eutectic system with eutectic temperature about 945 deg. C, the corresponding eutectic component is 35 mol% ZnO and 65 mol% Bi{sub 2}WO{sub 6}.

  4. Synthesis of ZnWO{sub 4} Electrode with tailored facets: Deactivating the Microorganisms through Photoelectrocatalytic methods

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, Su [Department of Materials Science and Engineering, Dalian Maritime University, Dalian 116026 (China); Zhou, Feng, E-mail: zhoufeng99@mails.tsinghua.edu.cn [Department of Materials Science and Engineering, Dalian Maritime University, Dalian 116026 (China); Huang, Naibao; Liu, Yujun; He, Qiuchen; Tian, Yu; Yang, Yifan [Department of Materials Science and Engineering, Dalian Maritime University, Dalian 116026 (China); Ye, Fei [Department of Materials Science and Engineering, Dalian University of Technology, Dalian 116026 (China)

    2017-01-01

    Highlights: • ZnWO{sub 4} with different exposed facets was synthesized by the hydrothermal method. • The reactive facets were tailored by varying the solution pH. • The photoelectrocatalysis was more efficient in deactivating the microorganism. - Abstract: 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, ZnWO{sub 4} with different exposed facets was synthesized by hydrothermal method, and ZnWO{sub 4} 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). ZnWO{sub 4} 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 ZnWO{sub 4} 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 ZnWO{sub 4}.

  5. Structural studies of WO3-TeO2 glasses by high-Q-neutron diffraction and Raman spectroscopy

    International Nuclear Information System (INIS)

    Khanna, A.; Kaur, A.; Krishna, P.S.R.; Shinde, A.B.

    2013-01-01

    Glasses from the system: xWO 3 -(100-x)TeO 2 (x=15, 20 and 25 mol %) were prepared by melt quenching technique and characterized by density, UV-visible absorption spectroscopy, Differential Scanning Calorimetry (DSC), Raman spectroscopy and high-Q neutron diffraction measurements. Glass density and glass transition temperature increased with increase in WO 3 concentration, Raman spectroscopy indicated the conversion of TeO 4 units into TeO 3 units with increase in WO 3 content. The increase in glass transition temperature with the incorporation of WO 3 was attributed to the increase in average bond strength of the glass network since the bond dissociation energy of W-O bonds (672 kJ/mol) is significantly higher than that of Te-O bonds (376 kJ/mol). UV-visible studies found a very strong optical absorption band due to W 6+ ions, just below the absorption edge. High-Q neutron diffraction measurements were performed on glasses and radial distribution function analyses revealed changes in W-O and Te-O correlations in the glass network. The findings about changes in glass structure from neutron diffraction studies were consistent with structural information obtained from Raman spectroscopy and structure-property correlations were made. (author)

  6. Facile synthesis of 2-D Cu doped WO3 nanoplates with structural, optical and differential anti cancer characteristics

    Science.gov (United States)

    Mehmood, Faisal; Iqbal, Javed; Gul, Asma; Ahmed, Waqqar; Ismail, M.

    2017-04-01

    Simple chemical co-precipitation method has been employed to synthesize two dimensional copper (Cu) doped tungsten oxide (WO3) nanoplates. A numbers of characterization techniques have been used to investigate their structural, optical and biocompatible anti cancer properties. The XRD results have confirmed the monoclinic crystal structure of WO3 nanoplates, and also successful doping of Cu ions into the WO3 crystal lattice. The presence of functional groups and chemical bonding have been verified through FTIR and Raman spectroscopy. The SEM images demonstrate that both undoped and Cu doped WO3 samples have squares plate like morphology. The EDX spectra confirm the presence of Cu, W and O ions. Diffuse reflectance spectroscopy (DRS) analysis has revealed a substantial red-shift in the absorption edge and a decrease in the band gap energy of nanoplates with Cu doping. Photoluminescence spectroscopy has been used to study the presence of defects like oxygen vacancies. Furthermore, the differential cytotoxic properties of Cu doped WO3 samples have been evaluated against human breast (MCF-7) and liver (Hep-2) cancer cells with ectocervical epithelial (HECE) healthy cells. The present findings confirm that the Cu doped WO3 nanoplates can be used as an efficient biocompatible anti cancer agent.

  7. Origin of TSL peaks located at 200-250 K in UV-irradiated PbWO4 crystals

    International Nuclear Information System (INIS)

    Fabeni, P.; Krasnikov, A.; Laguta, V.V.; Nikl, M.; Pazzi, G.P.; Susini, C.; Zazubovich, S.

    2007-01-01

    Thermally stimulated luminescence (TSL) was studied for many PbWO 4 crystals after their selective irradiation at 80-220 K in the 3.4-5.0 eV energy range to clarify the origin of the defects responsible for the TSL peaks located in the 200-250 K range. The conclusion is made that both in PbWO 4 and PbWO 4 :Mo crystals the total TSL intensity and the intensity ratio of various TSL peaks are mainly determined by the concentration and type of oxygen and lead vacancies which depend on the crystal preparation and annealing conditions and on the concentration of trivalent rare-earth impurity ions. The TSL peak near 200 K is ascribed to {Pb + -WO 3 } centers and the peak in the 210-230 K range, to the electron centers, containing oxygen vacancies of the type of WO 2 and WO. Only the 250 K peak arises from electron MoO 4 3- centers. Thermally stimulated processes are accompanied with the green G(II) emission

  8. Preparation and photoelectric properties of p-CaFe2O4/n-WO3 composites

    International Nuclear Information System (INIS)

    Wan, Ruiqin; Jia, Caihong; Zhang, Weifeng

    2012-01-01

    Highlights: ► Surface photovoltage spectroscopy investigation on p-CaFe 2 O 4 /n-WO 3 composites. ► The photovoltaic response is enhanced in p-CaFe 2 O 4 /n-WO 3 composites. ► The multielectron process and high rate of carrier migration in WO 3 . - Abstract: Composites of p-CaFe 2 O 4 /n-WO 3 are prepared via a sol–gel technique. Their structures and optical properties are characterized with X-ray diffraction, scanning electron microscopy and UV–vis absorption spectroscopy. The photoelectric characteristics are investigated by surface photovoltage spectroscopy combined with electric field induced surface photovoltage spectroscopy. The results indicate that CaFe 2 O 4 can well form a p–n type composite with WO 3 , and the intensity and spectral region of surface photovoltaic response for the composites are strongly dependent on the molar ratio of two components. The enhancement in photoelectric properties and the effective separation of photogenerated carriers could be attributed to the energy level matching between the two components, multielectron process and the high migration rate in WO 3 .

  9. Judd–Ofelt analysis of spectroscopic properties of Eu3+:KLu(WO4)2 crystal

    International Nuclear Information System (INIS)

    Loiko, P.A.; Dashkevich, V.I.; Bagaev, S.N.; Orlovich, V.A.; Mateos, X.; Serres, J.M.; Vilejshikova, E.V.; Yasukevich, A.S.; Yumashev, K.V.; Kuleshov, N.V.; Dunina, E.B.; Kornienko, A.A.; Vatnik, S.M.; Pavlyuk, A.A.

    2015-01-01

    We report on a comprehensive spectroscopic study of monoclinic Eu:KLu(WO 4 ) 2 crystal concerning its potential applications in red lasers. Optical absorption and stimulated-emission cross-section spectra are determined for this crystal for the principal light polarizations, E || N p , N m and N g . The maximum σ SE corresponding to the 5 D 0 → 7 F 4 transition is 1.78×10 −20 cm 2 at 703.5 nm (for E || N m ). Spectroscopic properties of Eu:KLu(WO 4 ) 2 are modeled within the conventional Judd–Ofelt theory, as well as its modification for systems with an anomalously strong configuration interaction (ASCI), yielding absorption oscillator strengths, luminescence branching ratios for 5 D J → 7 F J' transitions and radiative lifetimes of the 5 D J states. Photoluminescent properties of Eu:KLu(WO 4 ) 2 are studied under UV/visible excitation. Polarized Raman spectra are measured for Eu:KLu(WO 4 ) 2 . - Highlights: • Top-seeded solution growth of Eu:KLu(WO 4 ) 2 monoclinic crystal. • Modeling of spectroscopic parameters with modified Judd–Ofelt theory. • Polarization-resolved absorption and stimulated-emission cross-section spectra. • Maximum stimulated-emission cross-section is 1.78×10 −20 cm 2 at 703.5 nm. • Polarized Raman spectroscopy of Eu:KLu(WO 4 ) 2 crystal.

  10. High-performance complementary electrochromic device based on WO3·0.33H2O/PEDOT and prussian blue electrodes

    Science.gov (United States)

    Yue, Yanfang; Li, Haizeng; Li, Kerui; Wang, Jinmin; Wang, Hongzhi; Zhang, Qinghong; Li, Yaogang; Chen, Pei

    2017-11-01

    The device assembly plays an important role in affecting the electrochromic (EC) performance of an electrochromic device (ECD). Here, WO3·0.33H2O films are fabricated by a hydrothermal method and then PEDOT:PSS are spin-coated on the surface of WO3·0.33H2O films. Finally, the WO3·0.33H2O/PEDOT films are assembled with electrodeposited prussian blue (PB) to fabricate the WO3·0.33H2O/PEDOT-PB complementary electrochromic devices (ECDs). Compared with pure WO3·0.33H2O and WO3·0.33H2O/PEDOT single-active-layer structure ECDs, the complementary ECD exhibits higher optical modulation, higher coloration efficiency and faster response time, which would provide a promising platform for energy-saving smart (ESS) window.

  11. Investigation of multiferroic properties in MnWO{sub 4} by SHG-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Maringer, Michael; Meier, Dennis; Lottermoser, Thomas; Yuan, Gouliang; Fiebig, Manfred [HISKP, Universitaet Bonn (Germany); Becker, Petra; Bohaty, Ladislav [Institut fuer Kristallographie, Universitaet zu Koeln (Germany)

    2008-07-01

    Magnetoelectric multiferroics, i.e. compounds displaying magnetic and ferroelectric order in the same phase, attract considerable attention from the point of view of potential device application as well as fundamental physics. In the so-called spin-spiral compounds the interaction is particularly pronounced. Here we introduce optical second harmonic generation (SHG) as a powerful tool for the study of magnetic and eletronic properties and their magnetoelectric interaction in spin-spiral compounds, taking MnWO{sub 4} as an example. SHG gives detailed information about the symmetry of crystalline phases and about symmetry changes caused by phase transitions. In particular, in MnWO{sub 4} the (anti)ferromagnetic incommensurate phase and the magnetically induced ferroelectric, state are investigated. Although the magnetically induced spontaneous polarization is about four orders of magnitude weaker than in a conventional ferroelectric, a pronounced SHG signal is obtained.

  12. Time resolved measurements of the multiferroic switching in MnWO4

    Energy Technology Data Exchange (ETDEWEB)

    Baum, Max; Finger, Thomas; Braden, Markus [II. Physikalisches Institut, Universitaet Koeln (Germany); Leist, Jeannis [Institut fuer Physikalische Chemie, Georg-August-Universitaet Goettingen (Germany); Schmalzl, Karin [Juelich Centre for Neutron Science (JCNS), ILL, Grenoble (France); Regnault, Louis-Pierre [Institut Nanosciences et Cryogenie, CEA-Grenoble (France); Becker, Petra; Bohaty, Ladislav [Institut fuer Kristallographie, Universitaet Koeln (Germany)

    2011-07-01

    Multiferroic materials or compounds with a strong magnetoelectric effect posses a large application potential in data storage techniques. Quite recently, systems with a peculiar spiral magnetic order were shown to directly induce a spontaneous electric polarisation and to exhibit giant magnetoelectric and magnetocapacitance effects, among them MnWO4. Neutron scattering with spherical polarisation analysis gives direct access to the chiral component of the magnetic structure which is directly linked to the electric polarisation and thus may be tunable by an electric field. In MnWO4 it is possible to drive multiferroic hysteresis loops at constant temperature as a function of the electric field. We broadened our investigations in this topic and present time resolved measurements of magnetoelectric switching. We applied stroboscopic techniques in order to investigate how fast the chiral component of the magnetic structure adapts to an instantaneously switched electric field. The time scale of the response is remarkable slow, in the range of 3 - 20 ms.

  13. Polarization-dependent X-ray absorption spectroscopy of MnWO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Hollmann, Nils; Hu, Zhiwei; Tjeng, Liu Hao [II. Physikalisches Institut, Universitaet zu Koeln (Germany); Bohaty, Ladislav; Becker-Bohaty, Petra [Kristallographisches Institut, Universitaet zu Koeln (Germany); Tanaka, Arata [Department of Quantum Matter, Hiroshima University (Japan)

    2008-07-01

    Multiferroic materials which combine magnetism and ferroelectricity currently attract considerable attention. One of the recently discovered multiferroic materials is MnWO{sub 4} (Huebnerite). It belongs to the group of multiferroics where a spontaneous electric polarization is caused by a spiral magnetic structure with a spin rotation axis not coinciding with the propagation vector. To investigate the details of this astonishing combination of electronic and magnetic properties, we look at the electronic structure with the use of polarization-dependent X-ray absorption spectroscopy on single crystals of MnWO{sub 4}. The analysis of the experimental data on the L-edge of Mn is done by a configuration interaction calculation and is discussed.

  14. Coexistence of ferroelectric and long-wavelength magnetic ordering in MnWO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Meier, Dennis; Maringer, Michael; Lottermoser, Thomas; Yuan, Gouliang; Fiebig, Manfred [HISKP, Universitaet Bonn (Germany); Becker, Petra; Bohaty, Ladislav [Institut fuer Kristallographie, Universitaet zu Koeln (Germany)

    2008-07-01

    The strong interest in magnetoelectric multiferroics is due to their potential concerning the design of novel multifunctional devices, as well as to their unusual physical properties. Among these, TbMnO{sub 3}, Ni{sub 3}V{sub 2}O{sub 8}, and MnWO{sub 4} form a particularly challenging group: The key factor for ferroelectricity lies in the long-wavelength magnetic order. However, the nature of the ferroelectric (FE) state in such a spiral magnet and its relation to the magnetic ordering is largely unclear. Here we report about the spatial distribution of FE domains in MnWO{sub 4}, revealed by optical second harmonic generation (SHG). Although the spontaneous polarization in this ferroelectric is magnetically induced, 180 domains as in a conventional ferroelectric are observed.

  15. Synthesis and characterization of WO{sub 3} nanostructures prepared by an aged-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Huirache-Acuna, R., E-mail: rafael_huirache@yahoo.it [CFATA-UNAM, Boulevard Juriquilla 3001, Juriquilla Queretaro, 76230 (Mexico); Universidad La Salle Morelia, Av. Universidad 500, Mpio. Tarimbaro Mich., 58880 (Mexico); Paraguay-Delgado, F. [Centro de Investigacion en Materiales Avanzados, S.C. CIMAV, Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chih., 31109 (Mexico); Albiter, M.A.; Lara-Romero, J. [Facultad de Ingenieria Quimica, Universidad Michoacana de San Nicolas de Hidalgo, Morelia Mich., 58000 (Mexico); Martinez-Sanchez, R. [Centro de Investigacion en Materiales Avanzados, S.C. CIMAV, Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chih., 31109 (Mexico)

    2009-09-15

    Nanostructures of tungsten trioxide (WO{sub 3}) have been successfully synthesized by using an aged route at low temperature (60 deg. C) followed by a hydrothermal method at 200 deg. C for 48 h under well controlled conditions. The material was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Specific Surface Area (S{sub BET}) were measured by using the BET method. The lengths of the WO{sub 3} nanostructures obtained are between 30 and 200 nm and their diameters are from 20 to 70 nm. The growth direction of the tungsten oxide nanostructures was determined along [010] axis with an inter-planar distance of 0.38 nm.

  16. Synthesis and characterization of WO3 nanostructures prepared by an aged-hydrothermal method

    International Nuclear Information System (INIS)

    Huirache-Acuna, R.; Paraguay-Delgado, F.; Albiter, M.A.; Lara-Romero, J.; Martinez-Sanchez, R.

    2009-01-01

    Nanostructures of tungsten trioxide (WO 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 BET ) were measured by using the BET method. The lengths of the WO 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.

  17. Study of vibrational spectra of beta-LiYb(WO4)2

    International Nuclear Information System (INIS)

    Kondratov, O.I.; Efremov, V.A.; Petrov, K.I.; Fomichev, V.V.

    1978-01-01

    The Raman and infrared absorption spectra (up to 30 cm -1 ) of β-Li Yb(WO 4 ) 29 and a spectrum of an isotope-substituted, with respect to lithium, sample have been measured. Frequencies and shapes of normal vibration of two non-equivalent crystal directions have been calculated in a polymer approximation. The system of force constants has been determined. The frequency branches of the vibrations have been calculated when a phase vector changes from S=1 to 100 and atoms displacements. The calculation results have shown that a considerable contribution to the vibrations of end W-O bonds (the region of 900-930 cm -1 ) is made by the coordinates of the n-O bonds (where M is Li or Yb) elongation and by deformation of the WOM and OMO angles

  18. In situ microscopy of rapidly heated nano-Al and nano-Al/WO3 thermites

    International Nuclear Information System (INIS)

    Sullivan, Kyle T.; Zachariah, Michael R.; Chiou, Wen-An; Fiore, Richard

    2010-01-01

    The initiation and reaction mechanism of nano-Al and nano-Al thermites in rapid heating environments is investigated in this work. A semiconductor-based grid/stage was used, capable of in situ heating of a sample from room temperature to 1473 K, and at a rate of 10 6 K/s, inside an electron microscope. Nano-Al was rapidly heated in a transmission electron microscope, and before and after images indicate that the aluminum migrates through the shell, consistent with a diffusion-based mechanism. A nano-Al/WO 3 composite was then heated in a scanning electron microscope. The results indicate that a reactive sintering mechanism is occurring for the nano-Al/WO 3 thermite, as the products are found to be in surface contact and significantly deformed after the heating pulse.

  19. Formation of W/O microemulsion based on natural glycolipid biosurfactant, mannosylerythritol lipid-a.

    Science.gov (United States)

    Worakitkanchanakul, Wannasiri; Imura, Tomohiro; Morita, Tomotake; Fukuoka, Tokuma; Sakai, Hideki; Abe, Masahiko; Rujiravanit, Ratana; Chavadej, Sumaeth; Kitamoto, Dai

    2008-01-01

    Mannosylerythritol lipid-A (MEL-A) is a glycolipid biosurfactant abundantly produced from soybean oil by microorganisms at a yield of up to 100 g/L. In this study, the formation of water-in-oil (W/O) microemulsion based on the single component of MEL-A was confirmed using dynamic light scattering (DLS) and freeze fracture electron microscopy (FF-EM). DLS and FF-EM measurements revealed that the diameter of the microemulsion increases with an increase in water-to-surfactant mole ratio (W(0)) ranging from 20 to 60 nm, and the maximum W(0) value was found to be 20, which is as high as that of soybean lecithin. Glycolipid biosurfactant has a great potential for the formation of W/O microemulsion without using any cosurfactants.

  20. A New Hydrogen Sensor Based on SNS Fiber Interferometer with Pd/WO3 Coating

    Directory of Open Access Journals (Sweden)

    Jinxin Shao

    2017-09-01

    Full Text Available This paper presents a new hydrogen sensor based on a single mode–no core–single mode (SNS fiber interferometer structure. The surface of the no core fiber (NCF was coated by Pd/WO3 film to detect the variation of hydrogen concentration. If the hydrogen concentration changes, the refractive index of the Pd/WO3 film as well as the boundary condition for light propagating in the NCF will all be changed, which will then cause a shift into the resonant wavelength of interferometer. Therefore, the hydrogen concentration can be deduced by measuring the shift of the resonant wavelength. Experimental results demonstrated that this proposed sensor had a high detection sensitivity of 1.26857 nm/%, with good linearity and high accuracy (maximum 0.0055% hydrogen volume error. Besides, it also possessed the advantages of simple structure, low cost, good stability, and repeatability.

  1. Red Eu,Yb:KY(WO4)2 laser at ∼702 nm

    International Nuclear Information System (INIS)

    Dashkevich, V I; Orlovich, V A; Bui, A A; Bagayev, S N; Vatnik, S M; Loiko, P A; Yumashev, K V; Yasukevich, A S; Kuleshov, N V; Pavlyuk, A A

    2015-01-01

    In this letter, laser operation is demonstrated with a Eu,Yb: KY(WO 4 ) 2 crystal on the 5 D 0   →   7 F 4 transition of the Eu 3+ ion. When pumping into the 7 F 1   →   5 D 1 absorption band by a diode-pumped Nd 3+ :KGd(WO 4 ) 2 /KTP laser power-scaled at 533.6 nm up to a watt-level, we achieved 2.5 mW of the continuous wave (CW) red output at ∼702.1 nm. At quasi-CW pumping with a duty cycle of 10%, the peak power of the ms-long pulses arrived at ∼19 mW, corresponding to a green-to-red conversion efficiency of 0.8%. (letter)

  2. A hierarchically porous anatase TiO2 coated-WO3 2D IO bilayer film and its photochromic properties.

    Science.gov (United States)

    Li, Hua; Wu, Huazhong; Xiao, Jiajia; Su, Yanli; Robichaud, Jacques; Brüning, Ralf; Djaoued, Yahia

    2016-01-18

    A hierarchically porous anatase TiO2 coated-WO3 2D inverse opal (IO) bilayer film was fabricated on ITO glass using a layer by layer route with a hierarchically porous TiO2 top layer and an ordered super-macroporous WO3 2D IO bottom layer. This novel TiO2 coated-WO3 2D IO bilayer film was evaluated for photochromic applications.

  3. Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter

    CERN Document Server

    Adzic, P.; Andelin, D.; Anicin, I.; Antunovic, Z.; Arcidiacono, R.; Arenton, M.W.; Auffray, E.; Argiro, S.; Askew, A.; Baccaro, S.; Baffioni, S.; Balazs, M.; Bandurin, D.; Barney, D.; Barone, L.M.; Bartoloni, A.; Baty, C.; Beauceron, S.; Bell, K.W.; Bernet, C.; Besancon, M.; Betev, B.; Beuselinck, R.; Biino, C.; Blaha, J.; Bloch, P.; Borisevitch, A.; Bornheim, A.; Bourotte, J.; Brown, R.M.; Buehler, M.; Busson, P.; Camanzi, B.; Camporesi, T.; Cartiglia, N.; Cavallari, F.; Cecilia, A.; Chang, P.; Chang, Y.H.; Charlot, C.; Chen, E.A.; Chen, W.T.; Chen, Z.; Chipaux, R.; Choudhary, B.C.; Choudhury, R.K.; Cockerill, D.J.A.; Conetti, S.; Cooper, S.I.; 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.; Cornell U., LNS.; 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.; Malcles, 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.; Mine, 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, D.G.; Piroue, 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.; Stockli, F.; Swain, J.; Tabarelli de Fatis, T.; Takahashi, M.; Tancini, V.; Teller, O.; Theofilatos, K.; Thiebaux, C.; Timciuc, V.; Timlin, C.; Titov, Maxim P.; Topkar, A.; Triantis, F.A.; Troshin, S.; Tyurin, N.; Ueno, K.; Uzunian, A.; Varela, J.; Verrecchia, P.; Veverka, J.; Virdee, T.; Wang, M.; Wardrope, D.; Weber, M.; Weng, J.; Williams, J.H.; Yang, Y.; Yaselli, I.; Yohay, R.; Zabi, A.; Zelepoukine, S.; Zhang, J.; Zhang, L.Y.; Zhu, K.; Zhu, R.Y.

    2010-01-01

    Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered.

  4. Synthesis and characterization of MoO3–WO3 composite thin films ...

    Indian Academy of Sciences (India)

    H M Farveez Ahmed and Noor Shahina Begum technique. The precursor solution for deposition of MoO3–. WO3 was prepared by dissolving Mo (99·9% pure, Fluka chemicals) and W (99·9%, Aldrich chemicals) powder sepa- rately in 30% ice-cold solution of H2O2 and acetic acid. The reaction mixtures were kept overnight ...

  5. Growth of ultra radiation hard NaBi(WO4)2 single crystal

    International Nuclear Information System (INIS)

    Govind Singh, S.; Tyagi, Mohit; Singh, Awadh K.; Sangeeta

    2009-01-01

    Single crystals of undoped NaBi(WO 4 ) 2 were grown under different condition by Czochralski technique. Radiation hardness of the crystals was studied by irradiating them up to 10''5 and 10''6 Gy dose at a fast rate (2 Gy/sec) using 60 Co as a gamma source. Transmission spectra of the crystal samples were recorded and analyzed. It is found that crystal grown from recrystalized charge shows very good optical quality and excellent radiation hardness. (author)

  6. Effect of SiO2 Overlayer on WO3 Sensitivity to Ammonia

    Directory of Open Access Journals (Sweden)

    Vibha Srivastava

    2010-06-01

    Full Text Available Ammonia gas sensing properties of tungsten trioxide thick film sensor was investigated. The doping of noble catalysts such as Pt, Pd, Au enhanced the gas sensitivity. Platinum doping was found to result in highest sensitivity. Remarkable sensitivity enhancement was realized by coating WO3 thick film sensors with SiO2 overlayer. Sol gel process derived silica overlayer increased ammonia gas sensitivity for doped as well as undoped sensor.

  7. Controlled synthesis and structure characterization of nanostructured MnWO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Hu, W.B., E-mail: w.hu@tom.com [Hubei Institute for Nationalities, Enshi 445000 (China); Nie, X.L.; Mi, Y.Zh. [Hubei Institute for Nationalities, Enshi 445000 (China)

    2010-01-15

    Using Mn to partly substitute the W in W{sub 18}O{sub 49} nanowires, the synthesis of MnWO{sub 4} hubnerite nano-cocoons is described in this paper, by using mixed MnCl{sub 2} and WCl{sub 6} as the precursors and cyclohexanol as the solvent, in a simple solvothermal process. Detailed characterization of the resulting products, using electron microscopy and spectroscopy, has shown that the gradual increase of MnCl{sub 2} concentration changes the long W{sub 18}O{sub 49} nanowires to cocoon-like nanomaterials of stable MnWO{sub 4} phase. The driving force for such transformations is attributed to the Mn{sup 2+} inclusion within the W{sub 18}O{sub 49}. At low Mn{sup 2+} concentration, internal stresses would be introduced to the W{sub 18}O{sub 49} nanowires; whilst at high Mn{sup 2+} concentration close to the stoichiometric composition of MnWO{sub 4}, the formation of the nano-cocoons is triggered by the intrinsic crystalline feature of the hubnerite. It is believed that a combination of the initial nanowire nucleation and competing growth, and of self-assembly of neighboring parallel nanowires, leads to the final structure.

  8. Controlled synthesis and structure characterization of nanostructured MnWO4

    International Nuclear Information System (INIS)

    Hu, W.B.; Nie, X.L.; Mi, Y.Zh.

    2010-01-01

    Using Mn to partly substitute the W in W 18 O 49 nanowires, the synthesis of MnWO 4 hubnerite nano-cocoons is described in this paper, by using mixed MnCl 2 and WCl 6 as the precursors and cyclohexanol as the solvent, in a simple solvothermal process. Detailed characterization of the resulting products, using electron microscopy and spectroscopy, has shown that the gradual increase of MnCl 2 concentration changes the long W 18 O 49 nanowires to cocoon-like nanomaterials of stable MnWO 4 phase. The driving force for such transformations is attributed to the Mn 2+ inclusion within the W 18 O 49 . At low Mn 2+ concentration, internal stresses would be introduced to the W 18 O 49 nanowires; whilst at high Mn 2+ concentration close to the stoichiometric composition of MnWO 4 , the formation of the nano-cocoons is triggered by the intrinsic crystalline feature of the hubnerite. It is believed that a combination of the initial nanowire nucleation and competing growth, and of self-assembly of neighboring parallel nanowires, leads to the final structure.

  9. Composite WO3/TiO2 nanostructures for high electrochromic activity.

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, Karla Rosa; Stephens, Zachary Dan.; Robinson, David B.

    2013-05-01

    A composite material consisting of TiO2 nanotubes (NTs) with WO3 electrodeposited homogeneously on its surface has been fabricated, detached from its substrate, and attached to a fluorine-doped tin oxide film on glass for application to electrochromic (EC) reactions. A paste of TiO2 made from commercially available TiO2 nanoparticles creates an interface for the TiO2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length on the current density and the EC contrast of the material were studied. The EC redox reaction seen in this material is diffusion- limited, having relatively fast reaction rates at the electrode surface. The composite WO3/TiO2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast and longer memory time compared with the pure WO3 and TiO2.

  10. Visualization of X-ray Beam Using CdWO4 Crystal for Macromolecular Crystallography

    Directory of Open Access Journals (Sweden)

    Kazimierz J. Gofron

    2011-12-01

    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.

  11. Spin orbit torques in W(O) based three terminal magnetic memory devices

    Science.gov (United States)

    Zhang, Jie; Phung, Timothy; Garg, Chirag; Rettner, Charles; Hughes, Brian. P.; Yang, See-Hun; Parkin, Stuart. S. P.

    Recently, there has been a large interest in using spin orbit torques to controllably manipulate the magnetic order parameter in several promising magnetic memory devices such as racetrack memory and spin transfer torque MRAM. The efficient operation of such devices necessitates the finding of materials which exhibit efficient conversion of charge currents to spin orbit torques. This is typically quantified by the so-called spin Hall angle. The most efficient spin orbit torque generator to date based on the use of conventional metallic materials is W(O), wherein the effective spin hall angle is found to be -0.5. Here, we explore the use of W(O) to manipulate magnetization in three terminal magnetic memory devices. We find, consistent with the large spin orbit torques, observed in W(O), that the critical current required for switching a magnetic element is significantly smaller than compared to other metallic systems such as Pt, β-W, and Ta. Lastly, we shall discuss the technologically important high speed ( ns time scale) switching dynamics in these devices and the role of complex micromagnetic states upon the switching process.

  12. Carbon materials as additives to WO3 for an enhanced conversion of simulated solar light

    Directory of Open Access Journals (Sweden)

    Rocío Jiménez Carmona

    2016-02-01

    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.

  13. A beam test of PbWO sub 4 Cherenkov radiators

    CERN Document Server

    Kobayashi, M; Yoshimura, Y; Komatsubara, T K; Mimori, K; Omata, K; Sekiguchi, T; Tsunemi, T; Yoshioka, T; Tamagawa, Y; Shirasaka, H; Fujiwara, T; Usuki, Y; Ishii, M

    2002-01-01

    PbWO sub 4 heavily doped with trivalent rare-earth ions like La sup 3 sup + , Gd sup 3 sup + , Y sup 3 sup + , etc. has recently been proposed as an excellent new, heavy and radiation-hard Cherenkov radiator, and the upper limit of the remaining scintillation light yield (LY) was obtained from measurement of radioisotope gamma-rays. Since then, we have made a quantitative study of the remaining scintillation LY using a 0.5-1 GeV/c pi sup + /p/d beam. Compared with a standard PbWO sub 4 : Gd(80 at ppm) scintillator, the scintillation LY is quenched to 4.8%, 6.0%, and 11.6% for La sup 3 sup + concentration of 8 at%, La sup 3 sup + of 5 at% and Gd sup 3 sup + of 3 at%, respectively. The scintillation LY remaining in PbWO sub 4 : La(8 at%) was as weak as 15% of the Cherenkov LY for relativistic charged particles.

  14. Synthesis and Characterization of WO3/Graphene Nanocomposites for Enhanced Photocatalytic Activities by One-Step In-Situ Hydrothermal Reaction

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Hu

    2018-01-01

    Full Text Available Tungsten trioxide (WO3 nanorods are synthesized on the surface of graphene (GR sheets by using a one-step in-situ hydrothermal method employing sodium tungstate (Na2WO4·2H2O and graphene oxide (GO as precursors. The resulting WO3/GR nanocomposites are characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The results confirm that the interface between WO3 nanorod and graphene contains chemical bonds. The enhanced optical absorption properties are measured by UV-vis diffuse reflectance spectra. The photocatalytic activity of the WO3/GR nanocomposites under visible light is evaluated by the photodegradation of methylene blue, where the degradation rate of WO3/GR nanocomposites is shown to be double that of pure WO3. This is attributed to the synergistic effect of graphene and the WO3 nanorod, which greatly enhances the photocatalytic performance of the prepared sample, reduces the recombination of the photogenerated electron-hole pairs and increases the visible light absorption efficiency. Finally, the photocatalytic mechanism of the WO3/GR nanocomposites is presented. The synthesis of the prepared sample is convenient, direct and environmentally friendly. The study reports a highly efficient composite photocatalyst for the degradation of contaminants that can be applied to cleaning up the environment.

  15. Controllable topological transformation from BiOCl hierarchical microspheres to Bi{sub 2}WO{sub 6} superstructures in the Bi–W–Cl–O system

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Jiao [National Engineering Research Center for Manufacturing Equipment Digitization, Department of Mechanical Science and Engineering, Huazhong University of Science and Technology (HUST), No. 1037, Luoyu Road, Wuhan 430074 (China); State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Shi, Songxin, E-mail: shisx@hust.edu.cn [National Engineering Research Center for Manufacturing Equipment Digitization, Department of Mechanical Science and Engineering, Huazhong University of Science and Technology (HUST), No. 1037, Luoyu Road, Wuhan 430074 (China); Tang, Tengteng [State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Tian, Shouqin [State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Yang, Wenjuan [State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Zeng, Dawen [Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China)

    2015-09-15

    Graphical abstract: The three-dimensional (3D) Bi{sub 2}WO{sub 6} superstructures assembled by nanosheets were directly transformed topologically from BiOCl hierarchical microspheres via a facile one-pot solvothermal method. Furthermore, the crystal growth of Bi{sub 2}WO{sub 6} superstructure was confirmed to occur at the exposed plane (0 0 1) of BiOCl nanosheets with WO{sub 6}{sup 6−} units replacing the interlaminar Cl atoms. Their similar layered structures favored the controllable transformation of BiOCl to Bi{sub 2}WO{sub 6} through the substitution process. And this topological transformation may provide a new prospective to the synthesis of other 3D compounds. - Highlights: • Bi{sub 2}WO{sub 6} superstructures were prepared by topological transformation of BiOCl assembly. • Transformation process experienced three stages of BiOCl, BiOCl/Bi{sub 2}WO{sub 6} and Bi{sub 2}WO{sub 6}. • Bi{sub 2}WO{sub 6} superstructures grew at the exposed (0 0 1) facets of BiOCl nanosheets. • The growth mechanism was revealed from thermodynamic and kinetic dynamic aspects. - Abstract: In this work, three-dimensional (3D) Bi{sub 2}WO{sub 6} superstructures assembled by nanosheets were prepared using the topological transformation of BiOCl hierarchical microspheres via a facile one-pot solvothermal method. Interestingly, it was found that the transformation process experienced three stages including BiOCl, BiOCl/Bi{sub 2}WO{sub 6} composites and Bi{sub 2}WO{sub 6} with increasing solvothermal time at 150 °C, which was confirmed by X-Ray Diffraction (XRD), Raman spectrometer and Transmission Electron Microscopy (TEM) results. Importantly, the crystal growth of Bi{sub 2}WO{sub 6} superstructures occurred at the exposed (0 0 1) facets of BiOCl nanosheets with WO{sub 6}{sup 6−} units replacing the interlaminar Cl atoms. Also, the growth mechanism was revealed and discussed in the thermodynamic and kinetic dynamic aspects. Compared with BiOCl superstructures, the Bi

  16. Preparation of ultra-thin and high-quality WO{sub 3} compact layers and comparision of WO{sub 3} and TiO{sub 2} compact layer thickness in planar perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jincheng; Shi, Chengwu, E-mail: shicw506@foxmail.com; Chen, Junjun; Wang, Yanqing; Li, Mingqian

    2016-06-15

    In this paper, the ultra-thin and high-quality WO{sub 3} compact layers were successfully prepared by spin-coating-pyrolysis method using the tungsten isopropoxide solution in isopropanol. The influence of WO{sub 3} and TiO{sub 2} 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 TiO{sub 2} compact layer was analyzed by electrochemical impedance spectroscopy. The results revealed that the optimum thickness of WO{sub 3} and TiO{sub 2} compact layer was 15 nm and 60 nm. The planar perovskite solar cell with 15 nm WO{sub 3} compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO{sub 2} compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency. - Graphical abstract: The planar perovskite solar cell with 15 nm WO{sub 3} compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO{sub 2} compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency. Display Omitted - Highlights: • Preparation of ultra-thin and high-quality WO{sub 3} compact layers. • Perovskite solar cell with 15 nm-thick WO{sub 3} compact layer achieved PCE of 10.14%. • Perovskite solar cell with 60 nm-thick TiO{sub 2} compact layer achieved PCE of 12.64%.

  17. Electro-deposition metallic tungsten coatings in a Na{sub 2}WO{sub 4}-WO{sub 3} melt on copper based alloy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.H., E-mail: dreamerhong77@126.com [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Zhang, Y.C.; Liu, Q.Z.; Li, X.L.; Jiang, F. [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The tungsten coating (>1 mm) was obtained by electro-deposition method in molten salt. Black-Right-Pointing-Pointer Different thickness tungsten coatings were obtained by using different durations. Black-Right-Pointing-Pointer Good performance of coating was obtained when pulse parameters were modulated. - Abstract: The tungsten coating was prepared by electro-deposition technique on copper alloy substrate in a Na{sub 2}WO{sub 4}-WO{sub 3} melt. The coating's surface and cross-section morphologies as well as its impurities were investigated by XPS, SEM and line analysis. Various plating durations were investigated in order to obtain an optimal coating's thickness. The results demonstrated that the electro-deposited coating was compact, voidless, crackless and free from impurities. The tungsten coating's maximum Vickers hardness was measured to be 520 HV. The tungsten coating's minimum oxygen content was determined to be 0.018 wt%. Its maximum thickness was measured to be 1043.67 {mu}m when the duration of electrolysis was set to 100 h. The result of this study has demonstrated the feasibility of having thicker tungsten coatings on copper alloy substrates. These electrodeposited tungsten coatings can be potentially implemented as reliable armour for the medium heat flux plasma facing component (PFC).

  18. Preparation and characterization of zinc and copper co-doped WO3 nanoparticles: Application in photocatalysis and photobiology.

    Science.gov (United States)

    Mohammadi, Sanaz; Sohrabi, Maryam; Golikand, Ahmad Nozad; Fakhri, Ali

    2016-08-01

    In this study, pure, Zn, Cu, Zn,Cu co-doped WO3 nanoparticles samples were prepared by precipitation and co-precipitation methods. These nanoparticles were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDX), Dynamic light scattering (DLS), UV-visible and photoluminescence (PL) spectroscopy. The synthesized pure, Zn, Cu, Zn,Cu co-doped WO3 nanoparticles have smart optical properties and average sizes with 3.2, 3.12, 3.08 and 2.97eV of band-gap, 18.1, 23.2, 25.7 and 30.2nm, respectively. Photocatalytic activity of four nanoparticles was studying towards degradation of gentamicin antibiotic under ultraviolet and visible light irradiation. The result showed that Zn,Cu co-doped WO3 possessed high photocatalytic activity. The photocatalytic activity of WO3 nanoparticles could be remarkably increased by doping the Zn and Cu impurity. This can be attributed to the fact that the red shift of absorption edge and the trapping effect of the mono and co-doped WO3 nanoparticles. The research result presents a general and effective way to prepare different photocatalysts with enhanced visible and UV light-driven photocatalytic performance. Antibacterial activity of four different WO3 nanoparticles against Escherichia coli bacterium has been assessed by the agar disc method under light irradiation and dark medium. It is concluded from the present findings that WO3 nanoparticles can be used as an efficient antibacterial agent. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Advanced nanostructured photocatalysts based on reduced graphene oxide-flower-like Bi{sub 2}WO{sub 6} composites for an augmented simulated solar photoactivity activity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yukun [Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes, Ministry of Education, Hohai University, 1st Xikang Road, Nanjing 210098 (China); Chen, Lin [Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes, Ministry of Education, Hohai University, 1st Xikang Road, Nanjing 210098 (China); College of Environment, Hohai University, 1st Xikang Road, Nanjing 210098 (China); Wang, Yue [Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes, Ministry of Education, Hohai University, 1st Xikang Road, Nanjing 210098 (China); Zhu, Liang, E-mail: liangzhu_hh@163.com [Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes, Ministry of Education, Hohai University, 1st Xikang Road, Nanjing 210098 (China); College of Environment, Hohai University, 1st Xikang Road, Nanjing 210098 (China)

    2016-08-15

    Highlights: • A simple route was proposed to prepare flower-like Bi{sub 2}WO{sub 6} and RGO/Bi{sub 2}WO{sub 6}. • Cipro HCl was degraded firstly by RGO/Bi{sub 2}WO{sub 6} under the visible-light. • 2% RGO/Bi{sub 2}WO{sub 6} exhibited the best removal efficiency. - Abstract: A simple hydrothermal process was proposed to prepare the flower-like Bi{sub 2}WO{sub 6} architectures, and the as-synthesized Bi{sub 2}WO{sub 6} photocatalysts were further processed with the prepared graphene oxide (GO) to form novel reduced graphene oxide (RGO)/Bi{sub 2}WO{sub 6} composites. The nano-materials were characterized with the help of XRD, XPS, SEM, FTIR, UV-DRS, PL techniques to investigate their morphological, physical, optical, and photochemical properties. Photocatalytic performances of the pure flower-like Bi{sub 2}WO{sub 6} architectures and RGO/Bi{sub 2}WO{sub 6} composites were compared and evaluated through the degradation of ciprofloxacin hydrochloride (Cipro HCl) wastewater under the simulated visible light. It was found that the RGO/Bi{sub 2}WO{sub 6} composites displayed enhanced visible light-driven photocatalytic activities. It might be that the RGO loading not only effectively suppressed the electron–hole recombination, but also increased the light absorption ability. The effects of operating condition involved in the photocatalytic process were further examined, and the cycle-stability experiment demonstrated that as-obtained 2% RGO/Bi{sub 2}WO{sub 6} photocatalysts had good photocatalytic repeatability.

  20. Dispersion of Cs0.33WO3 particles for preparing its coatings with higher near infrared shielding properties

    Science.gov (United States)

    Liu, Jingxiao; Xu, Qiang; Shi, Fei; Liu, Suhua; Luo, Jiayu; Bao, Lei; Feng, Xiang

    2014-08-01

    In order to achieve good dispersion of Cs0.33WO3 particles and improve their near-infrared (NIR) shielding efficiency, the influences of ball-milling and dispersant on the dispersion stability of Cs0.33WO3 particles and its near infrared shielding properties were investigated. The microstructure, morphology, particle size distribution and Zeta potential of the particle samples were characterized by XRD, SEM and laser particle size analyzer. The results indicate that adding appropriate dispersant after ball-milling is conducive to dispersion of Cs0.33WO3 powders. Polyvinyl alcohol and titanate coupling agent have better effects on the dispersion of Cs0.33WO3 colloidal solution than poly-carboxylic salt dispersant. Particularly, the as-prepared Cs0.33WO3 coatings prepared from colloidal dispersion solution using titanate coupling agent at pH = 7 showed best visible light transmittance and near-infrared shielding properties, and have great potential applications as thermal insulation coatings for building and automotive glasses.

  1. Performance analysis of CRF-based learning for processing WoT application requests expressed in natural language.

    Science.gov (United States)

    Yoon, Young

    2016-01-01

    In this paper, we investigate the effectiveness of a CRF-based learning method for identifying necessary Web of Things (WoT) application components that would satisfy the users' requests issued in natural language. For instance, a user request such as "archive all sports breaking news" can be satisfied by composing a WoT application that consists of ESPN breaking news service and Dropbox as a storage service. We built an engine that can identify the necessary application components by recognizing a main act (MA) or named entities (NEs) from a given request. We trained this engine with the descriptions of WoT applications (called recipes) that were collected from IFTTT WoT platform. IFTTT hosts over 300 WoT entities that offer thousands of functions referred to as triggers and actions. There are more than 270,000 publicly-available recipes composed with those functions by real users. Therefore, the set of these recipes is well-qualified for the training of our MA and NE recognition engine. We share our unique experience of generating the training and test set from these recipe descriptions and assess the performance of the CRF-based language method. Based on the performance evaluation, we introduce further research directions.

  2. Efficient visible-light photocatalytic and enhanced photocorrosion inhibition of Ag2WO4 decorated MoS2 nanosheets

    Science.gov (United States)

    Thangavel, Sakthivel; Thangavel, Srinivas; Raghavan, Nivea; Alagu, Raja; Venugopal, Gunasekaran

    2017-11-01

    The use of two-dimensional nanomaterials as co-catalysts in the photodegradation of toxic compounds using light irradiation is an attractive ecofriendly process. In this study, we prepared a novel MoS2/Ag2WO4 nanohybrid via a one-step hydrothermal approach and the photocatalytic properties were investigated by the degradation of methyl-orange under stimulated irradiation. The nanohybrid exhibits enhanced efficiency in dye degradation compared to the bare Ag2WO4 nanorods; the same has been evidently confirmed with UV-visible spectra and total organic carbon removal analysis. The pseudo-first order rate constant of the nanohybrid is nearly 1.8 fold higher than that of the bare Ag2WO4 nanorods. With the aid of classical radical quenching and photoluminescence spectral analysis, a reasonable mechanism has been derived for the addition of MoS2 to nanohybrids to enhance the photocatalytic efficiency. MoS2 prevents photocorrosion of Ag2WO4 and also diminishes the number of photogenerated electron-hole recombination. Our findings could provide new insights in understanding the mechanism of the MoS2/Ag2WO4 nanohybrid as an efficient photocatalyst suitable for waste-water treatment and remedial applications.

  3. Response of the ABCG2 promoter in T47D cells and BeWo cells to sex hormone treatment.

    Science.gov (United States)

    Yasuda, Satoru; Kobayashi, Masaki; Itagaki, Shirou; Hirano, Takeshi; Iseki, Ken

    2009-09-01

    The aim of this study was to elucidate the effects of sex hormones on activity of the ABCG2 promoter in different cell lines. T47D cells and BeWo cells were used as models for ABCG2-expressing cell lines, and luciferase assays using ABCG2 promoter-luciferase constructs were performed. It was shown that progesterone increased the response of the ABCG2 promoter in T47D cells but not in BeWo cells. On the other hand, estradiol had no effect on response of the ABCG2 promoter in either cell line. However, response of the ABCG2 promoter was enhanced by overexpression of ERalpha in both T47D cells and BeWo cells. T47D cells had higher sensitivity to ERalpha than did BeWo cells. Furthermore, it was shown that the inductive effect of progesterone on the ABCG2 promoter was inhibited by addition of RU486 or mithramycin A. Therefore, it was thought that the ABCG2 promoter responded to stimulation of the progesterone receptor (PR)-Sp1 pathway in T47D cells. Furthermore, progesterone suppressed the response of the ABCG2 promoter by changing the expression levels of PR-A and PR-B in BeWo cells. These findings suggested that there are differences between cell lines in the regulation mechanism of ABCG2 expression by sex hormone treatment.

  4. Immobilized WO3 nanoparticles on graphene oxide as a photo-induced antibacterial agent against UV-resistant Bacillus pumilus

    Science.gov (United States)

    Hosseini, Farshad; Rasuli, Reza; Jafarian, Vahab

    2018-04-01

    We present the antibacterial and photo-catalytic activity of immobilized WO3 nanoparticles on graphene oxide sheets. WO3 nanoparticles were immobilized on graphene oxide using the arc discharge method in arc currents of 5, 20, 40 and 60 A. Tauc plots of the UV-visible spectra show that the band gap of the prepared samples decreases (to ~2.7 eV) with respect to the WO3 nanoparticles. Photo-catalytic activity was examined by the degradation of rhodamine B under ultra-violet irradiation and the results show that the photo-catalytic activity of WO3 nanoparticles is increased by immobilizing them on graphene oxide sheets. In addition, the photo-degradation yield of the samples prepared by the 5 A arc current is 84% in 120 min, which is more than that of the other samples. The antibacterial activity of the prepared samples was studied against Bacillus pumilus (B. pumilus) bacteria, showing high resistance to ultra-violet exposure. Our results show that the bare and immobilized WO3 nanoparticles become more active under UV irradiation and their antibacterial properties are comparable with Ag nanoparticles. Besides this, the results show that although the photo-catalytic activity of the post-annealed samples at 500 °C is less than the as-prepared samples, it is, however, more active against B. pumilus bacteria under UV irradiation.

  5. Preparation and optimization of CdWO{sub 4}-polymer nano-composite film as an alpha particle counter

    Energy Technology Data Exchange (ETDEWEB)

    Ziluei, Hossein [Nuclear Science and Technology Research Institute, AEOI, Tehran (Iran, Islamic Republic of); Azimirad, Rouhollah [Malek-Ashtar University of Technology, Tehran (Iran, Islamic Republic of); Mojtahedzadeh Larijani, Majid, E-mail: mmojtahedfr@yahoo.com [Nuclear Science and Technology Research Institute, AEOI, Tehran (Iran, Islamic Republic of); Ziaie, Farhoud [Nuclear Science and Technology Research Institute, AEOI, Tehran (Iran, Islamic Republic of)

    2017-04-21

    In this research work, CdWO{sub 4}/polymer composite films with different thicknesses were prepared using Poly-methyl acrylate polymer and synthesized CdWO{sub 4} powder. The CdWO{sub 4} powder was synthesized by a simple co-precipitation method in the laboratory. X-ray diffraction, photoluminescence, Fourier transformed infrared spectroscopy and energy-dispersive X-ray spectroscopy proved that the CdWO{sub 4} powder was successfully prepared. Moreover, photoluminescence analysis showed that adding polymer does not change the emission peak of CdWO{sub 4}. Also, the responses of all samples were measured using an {sup 241}Am alpha source with 1860 Bq activity. Results showed that the sample having thickness of 177 mg/cm{sup 2} has the best counting efficiency (over 2π geometry) among the others. The efficiency measurement was further evaluated using a {sup 230}Th source whose activity is 190.7 Bq. It revealed that the counting efficiency of this sample for both {sup 241}Am and {sup 230}Th was nearly equal.

  6. Per-service supervised learning for identifying desired WoT apps from user requests in natural language.

    Science.gov (United States)

    Yoon, Young

    2017-01-01

    Web of Things (WoT) platforms are growing fast so as the needs for composing WoT apps more easily and efficiently. We have recently commenced the campaign to develop an interface where users can issue requests for WoT apps entirely in natural language. This requires an effort to build a system that can learn to identify relevant WoT functions that fulfill user's requests. In our preceding work, we trained a supervised learning system with thousands of publicly-available IFTTT app recipes based on conditional random fields (CRF). However, the sub-par accuracy and excessive training time motivated us to devise a better approach. In this paper, we present a novel solution that creates a separate learning engine for each trigger service. With this approach, parallel and incremental learning becomes possible. For inference, our system first identifies the most relevant trigger service for a given user request by using an information retrieval technique. Then, the learning engine associated with the trigger service predicts the most likely pair of trigger and action functions. We expect that such two-phase inference method given parallel learning engines would improve the accuracy of identifying related WoT functions. We verify our new solution through the empirical evaluation with training and test sets sampled from a pool of refined IFTTT app recipes. We also meticulously analyze the characteristics of the recipes to find future research directions.

  7. Synthesis and characterizations of isolated WO{sub 4} anchored on mesoporous TiTUD-1 support

    Energy Technology Data Exchange (ETDEWEB)

    Pachamuthu, Muthusamy P. [Department of Chemistry, Bannari Amman Institute of Technology, Sathyamangalam, Erode, 638401 (India); Maheswari, Rajamanickam [Center for Environmentally Beneficial Catalysis (CEBC), The University of Kansas, Lawrence, KS, 66047 (United States); Ramanathan, Anand, E-mail: anand@ku.edu [Center for Environmentally Beneficial Catalysis (CEBC), The University of Kansas, Lawrence, KS, 66047 (United States)

    2017-04-30

    Highlights: • Incorporation of (WO{sub 4}{sup 2−}) species into amorphous mesoporous silicate TiTUD-1. • Typical TUD-1 structure with dispersed Ti{sup 4+} and WO{sub 4}{sup 2−} species. • FT Raman and XPS results evidenced the WO{sub 4}{sup 2−} species dispersion. • Catalyst with 20% W loading yields higher conversion in esterification reaction. - Abstract: The titanium incorporated mesoporous silicate TUD-1 (Si/Ti ratio 40) was synthesized by non-surfactant route, and utilized as a support for tungstate (WO{sub 4}{sup 2−}) species with variable loading (5–30 wt%). The structural and textural properties of these samples were evaluated from X-ray diffraction (XRD) and N{sub 2} physisorption studies. Diffuse reflectance UV–vis (DR UV–vis), Fourier transform infrared (FTIR), Fourier transform Raman (FT Raman) spectra evidenced the Ti{sup 4+} coordination and the formation of WO{sub 4}{sup 2−} species, further supported by X-ray photoelectron spectroscopy (XPS) studies. Scanning electron microscope–energy dispersive X-ray analysis (SEM-EDAX), High resolution transmission electron microscope (HRTEM) further support the materials morphology corroborating other characterizations. The catalytic activities of these materials were tested in the liquid phase, solvent free esterification of acetic acid with n-butanol. About 95% of acetic acid conversion resulted by these catalysts with 8 h of reaction time.

  8. Novel synthesis of WO{sub 3} nanocrystals through pyrolytic decomposition of tungstate-based inorganic-organic hybrid nanobelts

    Energy Technology Data Exchange (ETDEWEB)

    Chen Deliang, E-mail: dlchen@zzu.edu.cn [School of Materials Science and Engineering, Zhengzhou University, 100 Science Road, Zhengzhou 450001 (China); Wen Hejing; Chen Huimin; Wang Hailong; Zhang Rui; Xu Hongliang; Yang Daoyuan; Lu Hongxia [School of Materials Science and Engineering, Zhengzhou University, 100 Science Road, Zhengzhou 450001 (China)

    2009-08-15

    The paper described a novel approach toward WO{sub 3} nanocrystals by pyrolytically decomposing tungstate-based inorganic-organic hybrid nanobelts in air at 500-600 deg. C for 2 h. The above-mentioned hybrid nanobelts were derived via a reaction of layered H{sub 2}W{sub 2}O{sub 7}.xH{sub 2}O and n-octylamine in a reverse-micelle-like medium (H{sub 2}W{sub 2}O{sub 7}.xH{sub 2}O/n-octylamine/heptane). The as-obtained WO{sub 3} nanocrystals and their intermediate products were characterized by the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM and FE-SEM), thermoanalysis (TG-DSC), Fourier-transform infrared spectra (FT/IR), UV-vis absorption and X-ray photoelectron spectroscopy (XPS). The as-obtained WO{sub 3} nanocrystals had an apparent size of 20-50 nm, and took on a loose-aggregate-like morphology. The WO{sub 3} nanocrystals derived via the pyrolytic decomposition process were almost separated from each other and could be redispersed readily, while the WO{sub 3} nanocrystals obtained by the conventional acid-precipitation process tightly agglomerated into large particles with apparent sizes of several micrometers, without redispersibility even under an intense sonication treatment.

  9. Photoluminescence and photoconductivity studies on NaBi(WO4)2 single crystals: A promising Cherenkov radiator

    International Nuclear Information System (INIS)

    Tyagi, Mohit; Singh, S.G.; Sen, Shashwati; Singh, A.K.; Gadkari, S.C.

    2012-01-01

    Results of photoluminescence in conjunction with photoconductivity properties of NaBi(WO 4 ) 2 crystal are presented and explained with the help of calculated electronic and optical properties. Crystals were annealed in air/vacuum to change the local environment near (WO 4 ) 2- complex and consequently two emission bands near 470 and 520 nm could be separated for excitation at different energies. The activation energy for thermal quenching of emission was calculated to be 160 meV. The role of excitons and localization of charge carriers is explained on the basis of photoconductivity of these crystals that has been observed only intrinsically in contrast to iso-structurally PbWO 4 . - Highlights: → Results on photoluminescence and photoconductivity of NaBi(WO 4 ) 2 are reported. → These are explained with the help of calculated electronic and optical properties. → Crystals were annealed in air/vacuum to change the local environment near (WO 4 ) 2- . → Emission bands near 470 and 520 nm could be separated for different excitation. → The activation energy for thermal quenching of emission was found to be 160 meV.

  10. Synthesis and Visible-Light Photocatalytic Property of Bi2WO6Hierarchical Octahedron-Like Structures

    Directory of Open Access Journals (Sweden)

    Li Yuanyuan

    2008-01-01

    Full Text Available Abstract A novel octahedron-like hierarchical structure of Bi2WO6has been fabricated by a facile hydrothermal method in high quantity. XRD, SEM, TEM, and HRTEM were used to characterize the product. The results indicated that this kind of Bi2WO6crystals had an average size of ~4 μm, constructed by quasi-square single-crystal nanosheets assembled in a special fashion. The formation of octahedron-like hierarchical structure of Bi2WO6depended crucially on the pH value of the precursor suspensions. The photocatalytic activity of the hierarchical Bi2WO6structures toward RhB degradation under visible light was investigated, and it was found to be significantly better than that of the sample fabricated by SSR. The better photocatalytic property should be strongly associated with the high specific surface area and the abundant pore structure of the hierarchical octahedron-like Bi2WO6.

  11. Raman spectroscopy of WO3 nano-wires and thermo-chromism study of VO2 belts produced by ultrasonic spray and laser pyrolysis techniques

    CSIR Research Space (South Africa)

    Mwakikunga, BW

    2008-01-01

    Full Text Available Novel optical and electrical properties of newly synthesized nano-wires of monoclinic WO3 and nano-belts of rutile VO2 have been investigated by Raman spectroscopy and thermochromism studies respectively. Phonon confinement is observed in the WO3...

  12. Subsolidus phase relations of the SrO–WO3–CuO system at 800 °C in air

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Norby, Poul

    2012-01-01

    The subsolidus phase relations of the SrO–WO3–CuO system were investigated in air. The samples were equilibrated at 800 °C. Under these conditions, eight binary oxides are stable. The pseudo-ternary section contains two ternary oxide phases: the previously described Sr2CuWO6 phase as well as a new...

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

    DEFF Research Database (Denmark)

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

    2006-01-01

    Placenta-sequestering Plasmodium falciparum parasites causing pregnancy-associated malaria express pregnancy-specific variant surface antigens (VSA(PAM)). We report here that VSA(PAM)-expressing patient isolates adhere strongly to the choriocarcinoma cell line BeWo and that the BeWo line can...... be used to efficiently select for VSA(PAM) expression in vitro....

  14. A comparative study of humidity sensing and photocatalytic applications of pure and nickel (Ni)-doped WO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ramkumar, S. [Bannari Amman Institute of Technology, Department of Physics, Erode, Tamilnadu (India); Rajarajan, G. [Vidhya Mandhir Institute of Technology, Department of Physics, Erode, Tamilnadu (India)

    2017-06-15

    Nanocrystalline of pristine and nickel (Ni)-doped tungsten trioxide (WO{sub 3}) thin films was deposited by chemical bath deposition method. The concentrations of Ni ions were varied from 0 to 10 wt%. In order to improve the crystallinity of the films were annealed at 600 C for 2 h in the ambient atmosphere. X-ray diffraction results reveal that the WO{sub 3} doped with nickel crystallizes in monoclinic structure and the results are in good agreement with the standard JCPDS data (card no: 83-0951). AFM micrographs reveal that average grain size of about 27-39 nm for pure and Ni-doped WO{sub 3} thin films. In addition, the band gap of the Ni-doped WO{sub 3} nanostructures is facilely tunable by controlling the Ni contents. The humidity sensor setup was fabricated and measured for pure and Ni-doped WO{sub 3} thin film sensor with various level of RH (10-90%). The Ni-doped WO{sub 3} sensor showed fast response and high sensitivity than pure WO{sub 3}. The photocatalytic activities of the films were evaluated by degradation of methyl orange, methylene blue and phenol in an aqueous solution under visible light irradiation. The photocatalytic activity of WO{sub 3} nanostructures could be remarkably enhanced by doping the Ni impurity. (orig.)

  15. Effect of WO3 nanoparticle loading on the microstructural, mechanical and corrosion resistance of Zn matrix/TiO2-WO3 nanocomposite coatings for marine application

    Science.gov (United States)

    Popoola, A. P. I.; Daniyan, A. A.; Umoru, L. E.; Fayomi, O. S. I.

    2017-03-01

    In this study, for marine application purposes, we evaluated the effect of process parameter and particle loading on the microstructure, mechanical reinforcement and corrosion resistance properties of a Zn-TiO2-WO3 nanocomposite produced via electrodeposition. We characterized the morphological properties of the composite coatings with a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS). We carried out mechanical examination using a Dura Scan hardness tester and a CERT UMT-2 multi-functional tribological tester. We evaluated the corrosion properties by linear polarization in 3.5% NaCl. The results show that the coatings exhibited good stability and the quantitative particle loading greatly enhanced the structural and morphological properties, hardness behavior and corrosion resistance of the coatings. We observed the precipitation of this alloy on steel is greatly influenced by the composite characteristics.

  16. Synthesis, energy transfer and luminescence properties of Ca{sub 2}MgWO{sub 6}:Sm{sup 3+}, Bi{sup 3+} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Renping, E-mail: jxcrp@163.com [College of Mathematics and Physics, Jinggangshan University, Ji’an 343009 (China); Xu, Haidong; Luo, Wenjie [College of Mathematics and Physics, Jinggangshan University, Ji’an 343009 (China); Luo, Zhiyang [College of Mechanical Manufacture and Automation, Jinggangshan University, Ji’an 343009 (China); Guo, Siling [College of Mathematics and Physics, Jinggangshan University, Ji’an 343009 (China); Xiao, Fen [College of Mechanical Manufacture and Automation, Jinggangshan University, Ji’an 343009 (China); Ao, Hui [College of Mathematics and Physics, Jinggangshan University, Ji’an 343009 (China)

    2016-09-15

    Graphical abstract: PL spectra of Ca{sub 2}MgWO{sub 6}:Sm{sup 3+} and Ca{sub 2}MgWO{sub 6}:Sm{sup 3+}, Bi{sup 3+} phosphors with excitation at 407 nm, and the corresponding CIE chromaticity diagram and chromaticity coordinates. - Highlights: • Novel Ca{sub 2}MgWO{sub 6}:Sm{sup 3+}, Bi{sup 3+} phosphor is synthesized by solid-state reaction method in air. • Emission intensity of Ca{sub 2}MgWO{sub 6}:Sm{sup 3+} phosphor is enhanced ∼2 times after co-doped Bi{sup 3+} ion. • Charge compensation and energy transfer may be explained via luminescence properties. • Luminous mechanism is analyzed by energy level diagrams of WO{sub 6}{sup 6−} group, Sm{sup 3+} and Bi{sup 3+} ions. - Abstract: Novel Ca{sub 2}MgWO{sub 6}:Sm{sup 3+}, Bi{sup 3+} phosphor is synthesized by solid-state reaction method in air. Host Ca{sub 2}MgWO{sub 6} with excitation 300 nm emits blue light. Ca{sub 2}MgWO{sub 6}:Bi{sup 3+} phosphor with excitation 300 and 338 nm emits yellow light. Ca{sub 2}MgWO{sub 6}:Sm{sup 3+} phosphor with excitation 300 nm exhibits tunable emission from blue to red light by increasing Sm{sup 3+} doping concentration from 0 to 8 mol%, however, only emits red light with excitation 407 nm. Ca{sub 2}MgWO{sub 6}:Sm{sup 3+}, Bi{sup 3+} phosphor with excitation 300 and 338 nm emits red light. The optimal Sm{sup 3+} doping concentration is ∼5 mol% in Ca{sub 2}MgWO{sub 6}:Sm{sup 3+} phosphor. After Bi{sup 3+} ion is co-doped, luminescence properties of Ca{sub 2}MgWO{sub 6}:Sm{sup 3+} phosphor can be improved obviously because of Bi{sub 2}O{sub 3} as fluxing agent role and energy transfer from Bi{sup 3+} to Sm{sup 3+} ions. The possible luminous mechanism of Ca{sub 2}MgWO{sub 6}:Sm{sup 3+}, Bi{sup 3+} phosphor is analyzed and explained by simplified energy level diagrams of WO{sub 6}{sup 6−} group, Bi{sup 3+} and Sm{sup 3+} ions.

  17. WO3/Pt nanoparticles are NADPH oxidase biomimetics that mimic effector cells in vitro and in vivo

    Science.gov (United States)

    Clark, Andrea J.; Coury, Emma L.; Meilhac, Alexandra M.; Petty, Howard R.

    2016-02-01

    To provide a means of delivering an artificial immune effector cell-like attack on tumor cells, we report the tumoricidal ability of inorganic WO3/Pt nanoparticles that mimic a leukocyte’s functional abilities. These nanoparticles route electrons from organic structures and electron carriers to form hydroxyl radicals within tumor cells. During visible light exposure, WO3/Pt nanoparticles manufacture hydroxyl radicals, degrade organic compounds, use NADPH, trigger lipid peroxidation, promote lysosomal membrane disruption, promote the loss of reduced glutathione, and activate apoptosis. In a model of advanced breast cancer metastasis to the eye’s anterior chamber, we show that WO3/Pt nanoparticles prolong the survival of 4T1 tumor-bearing Balb/c mice. This new generation of inorganic photosensitizers do not photobleach, and therefore should provide an important therapeutic advance in photodynamic therapy. As biomimetic nanoparticles destroy targeted cells, they may be useful in treating ocular and other forms of cancer.

  18. Subsolidus phase relations in the ZnO-P{sub 2}O{sub 5}-WO{sub 3} system

    Energy Technology Data Exchange (ETDEWEB)

    Yin Shungao [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002 (China); Chen Dagui, E-mail: chendg@fjirsm.ac.c [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002 (China); Liu Weizhen; Wang Yongjing; Lin Zhang; Hong Yangping; Zhan Zhibing [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002 (China); Huang Feng, E-mail: fhuang@fjirsm.ac.c [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002 (China); Liang Jingkui [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002 (China)

    2010-04-30

    The subsolidus phase relations of the ZnO-P{sub 2}O{sub 5}-WO{sub 3} ternary system were investigated by means of X-ray diffraction (XRD). No ternary compound was found in this ternary system, while five binary compounds were obtained and six compatibility triangles were determined. The phase diagram of pseudobinary system Zn{sub 3}(PO{sub 4}){sub 2}-ZnWO{sub 4} was also constructed through XRD and differential thermal analysis (DTA) methods, which forms eutectic system with eutectic temperature about 990 {sup o}C. The corresponding eutectic component is 30 mol% ZnWO{sub 4} and 70 mol% Zn{sub 3}(PO{sub 4}){sub 2}.

  19. IR spectra and structure of glasses in the BaO-WO3-P2O5 system

    International Nuclear Information System (INIS)

    Miroshnichenko, O.Ya.; Mombelli, V.V.

    1979-01-01

    Studied are IR absorption spectra and determined are the main structural characteristics of tungstophosphate glasses of the BaO-WO 3 -P 2 O 5 system in all the area of glass formation. It is shown that the main structural components of their anion network are phosphate chains consisting of PO 4 tetrahedrons and tungstate chains consisting of WO 4 tetrahedrons and of WO 6 octahedrons. These chains are connected by P-O-W bridges into three-dimentional tungstophosphate network, where the ratio of phosphate and tungstate structural units and their polymerization degree change without limits depending on the glass composition. Analysis of concentration frequency dependence and spectral band intensity permit to clarify the effect of each component on the glass structure in all the area of glass formation of the triple system

  20. Synthesis and Characterization of Graphene Oxide-Modified Bi2WO6 and Its Use as Photocatalyst

    Directory of Open Access Journals (Sweden)

    Xiaoyue Hu

    2016-01-01

    Full Text Available A Bi2WO6 photocatalyst modified with graphene was synthesized in a two-step template-free hydrothermal process. The prepared samples were characterized to explore their properties. The photocatalytic activities of the prepared samples were investigated by degrading dye model, Rhodamine B (RhB, under visible light irradiation. This showed that the modified Bi2WO6 photocatalyst with 1.2 wt% of graphene greatly improved photocatalytic activity during the degradation of dye pollutants, compared to pure Bi2WO6. The enhancement can be interpreted as the integrated effects of ultrahigh charge carriers’ mobility and high adsorption of RhB on graphene. Additionally, effects including catalysts dosage amount, pH of RhB solution, and temperature of reactor on the photocatalytically degrading RhB were also studied and discussed.

  1. Surfactant Effect on Formation of CaWO4:Eu3+ Crystals with Distinguished Morphologies in Hydrothermal Ambient.

    Science.gov (United States)

    Chen, Ye-Qing; Yang, Guo-Tao; Luo, Jian-Yi; Yang, Ying-Shu; Zeng, Qing-Guang; Jeong, Jung Hyun

    2016-04-01

    Metal tungstates, expressed by the general formula of MWO4, have important properties and applications in photoluminescence, microwave applications, optical fibers, scintillator materials, humidity sensors, magnetic properties, and catalysts. In this paper, we report a successful synthesis of CaWO4:Eul+ crystals with various morphologies in mild hydrothermal conditions with surfacntant including sodium citrate, CTAB, PEG and citrate acid (CA). The formation of the crystals are strongly dependent on the employment of surfactant. The surfactant concentration has been found significant influence in the resulting morphologies due to different properties of each one. Extensive characterization have been performed by using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) in search of the formation mechanism of multi-morphological CaWO4:Eu3+ crystals. The growth mechanism of monodispersed CaWO4:EuS+ crystal are proposed. And the photoluminescence properties were investigated.

  2. Cross-cultural adaptation of the Work Disability Diagnosis Interview (WoDDI) for the Brazilian context.

    Science.gov (United States)

    Mininel, Vivian Aline; Felli, Vanda Elisa Andres; Loisel, Patrick; Marziale, Maria Helena Palucci

    2012-01-01

    The Work Disability Diagnosis Interview (WoDDI) is a structured interview guide developed by the University of Sherbrooke, Canada to help clinicians detect the most important work-related disability predictors and to identify one or more causes of prolonged absenteeism. This methodological study aims for the cross-cultural adaptation of the WoDDI for the Brazilian context. The method followed international guidelines for studies of this kind, including the following steps: initial translation, synthesis of translations, back translation, evaluation by an expert committee and testing of the penultimate version. These steps allowed obtaining conceptual, semantic, idiomatic, experiential and operational equivalences, in addition to content validity. The results showed that the translated WoDDI is adapted to the Brazilian context and can be used after training.

  3. WO3/Pt nanoparticles are NADPH oxidase biomimetics that mimic effector cells in vitro and in vivo

    International Nuclear Information System (INIS)

    Clark, Andrea J; Coury, Emma L; Meilhac, Alexandra M; Petty, Howard R

    2016-01-01

    To provide a means of delivering an artificial immune effector cell-like attack on tumor cells, we report the tumoricidal ability of inorganic WO 3 /Pt nanoparticles that mimic a leukocyte’s functional abilities. These nanoparticles route electrons from organic structures and electron carriers to form hydroxyl radicals within tumor cells. During visible light exposure, WO 3 /Pt nanoparticles manufacture hydroxyl radicals, degrade organic compounds, use NADPH, trigger lipid peroxidation, promote lysosomal membrane disruption, promote the loss of reduced glutathione, and activate apoptosis. In a model of advanced breast cancer metastasis to the eye’s anterior chamber, we show that WO 3 /Pt nanoparticles prolong the survival of 4T1 tumor-bearing Balb/c mice. This new generation of inorganic photosensitizers do not photobleach, and therefore should provide an important therapeutic advance in photodynamic therapy. As biomimetic nanoparticles destroy targeted cells, they may be useful in treating ocular and other forms of cancer. (paper)

  4. The effect of precursor aging on optical and electrochromic properties of WO3 thin films for making smart windows

    Directory of Open Access Journals (Sweden)

    A Abareshi

    2015-01-01

    Full Text Available This paper proposes a suitable method for increasing effective surface area of electrodeposited WO3 thin films. This is done because effective surface area improves optical and electrochromic properties in smart windows. Therefore, we investigated precursor aging atperoxytungstate precursor (0, 24, 48 and 72 h. Experiments showed by increasing aging time of the precursor solution, larger aggregates were formed. Their morphology, optical and cyclic voltammogram characterization showed that increasing aging time improves optical and electrochromic properties of WO3 thin films in 1M LiClO4-PC electrolyte. The WO3 films with aging time of 72 h exhibited a noticeable EC performance with variation of transmittance up to 72% at 633nm. The result indicated that using two electrochromic materials with complementary properties could improve the function of the device

  5. Development of Practical inventory analysis using an input-output table. Allocation problem by multi-prices of a commodity and procedure for combining process with input-output analyses; Sangyo renkanhyo wo mochiita jitsuyotekina inbentori bunseki shuho no kakuritsu. Ichizai taka ni yoru haibun mondai oyobi tsumiageho tono yugo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Hondo, H.; Uchiyama, Y. [Central Research Inst. of Electric Power Industry, Tokyo (Japan). Socio-economic Research Center

    1999-11-20

    This paper discusses two main problems to develop practical inventory analysis using an input-output (I-O) table. The first is the allocation problem caused by use of an actual I-O table, which indicates transaction among sectors on monetary unit. When direct and indirect emissions at the production of commodities are calculated using conventional I-O analysis method, the values are underestimated or overestimated due to the assumption that a commodity is sold at a uniform price to all consumers. In this paper, modified method is presented, reflecting the fact that a commodity is sold at different prices to each consumer. It is found that CO{sub 2} emission factors of commodities estimated using the modified method are different fro those using the conventional method. The second is the way to combine process analysis with I-O analysis for reasonable and practical inventory analysis. The merit of process analysis is precise estimation reflecting actual processes. On the other hand, I-O analysis theoretically enables consistent estimation taking account of all processes in society. This paper describes an inventory analysis method that makes the best use of merits of both. CO{sub 2} emission factor of a boiler is calculated using the method and the result proves the method to be available. (author)

  6. Steel beam to reinforced concrete column joints using steel plate connections. Pt. 2. Structural behavior of joints under cyclic loading; Koban setsugobu wo mochiita tekkin concrete chu to tekkotsu hari tono setsugobu ni kansuru kenkyu. 2. Churyo jujigata honegumi no suihei karyoku jikken

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K.; Tomitas, A.; Honma, K.; Ueno, M. [Kajima Corp., Tokyo (Japan)

    1999-09-30

    A column/beam structure having reinforced concrete columns and steel beams (RC column/S beam structure) enables the assemblies to be manufactured in a plant by using PCa for the column including joints, and allows the assembling work at a job site to be performed by a dry/stacking construction method consisting mostly of the assembly operation. The writers developed a steel plate joint, a steel plate with an opening in the center, which is fixed inside a column by merely penetrating the joint with main reinforcements of the column, as a new joining method in the RC column/S beam construction that facilitates the PCa column. As a result of a previously implemented experiment of drawing out the joint, it was confirmed that the joint fixed by penetrating with the main reinforcements showed a sufficient fixing performance without special reinforcement, and that no damage was caused locally to the main reinforcements by drawing out the steel plate for example. In the subject research, for the purpose of grasping the basic dynamical properties of a bridge using the joint, a framework test was conducted on the six specimens with a reinforcing method varied for the joint. As a result of the test, the joint, having the opening in the center and penetration with the column main reinforcements, demonstrated a full fixing performance, ensuring a stable load/deformation relation up to a layer deforming angle of R={+-}25rad. In particular, no surface separation was recognized between the joint and the column concrete, and no local fall-off or the like of the joint was confirmed. (translated by NEDO)

  7. 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

    Energy Technology Data Exchange (ETDEWEB)

    Kanbe, M.; Saito, M.; Ishihara, A.; Kabe, T. [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1996-10-28

    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.

  8. 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

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, T.; Ito, N.; Kimura, G.; Fukao, S.; Sunaga, N.; Tsunoda, M.; Muro, K. [Tokyo Metropolitan University, Tokyo (Japan)

    1996-10-27

    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.

  9. 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)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    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)

  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

    Energy Technology Data Exchange (ETDEWEB)

    Inazaki, T. [Public Works Research Institute, Tsukuba (Japan)

    1997-05-27

    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. 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

    Energy Technology Data Exchange (ETDEWEB)

    Inazaki, T. [Public Works Research Institute, Tsukuba (Japan)

    1996-05-01

    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.

  12. Achievement report for fiscal 1998. Development of an industrial rinsing equipment of environmentally harmonizing type using an ultra critical fluid (the second year); 1998 nendo seika hokokusho. Chorinkai ryutai wo mochiita kankyo chowagata kogyo senjo sochi no kaihatsu (dai 2 nendo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    This project is intended for environment friendly and pollution-free rinsing by using an ultra critical fluid of CO2 being an atmospheric constituent. It also has a purpose of establishing a new rinsing method implemented by an ultra precision component machine and device using such features possessed by the ultra critical fluid as high permeability and disinfecting activities. It is further intended of developing, fabricating, and practically using a rinsing equipment that makes possible precision rinsing of mechanical, electronic, optical and aeronautical components. Using the results of experiments performed in the previous year as the base, discussions were given on the relationship between the two aspects of the hardware aspect such as equipment configuration and piping of the rinsing equipment and the software aspect such as operating conditions and procedures and the rising effect. As a result, a new rinsing equipment of solvent circulation type was proposed. The basic design software for the specific equipment was completed, and an experimental equipment was designed and fabricated under the clean specifications. The performance evaluation and verification experiments were finished in the end of fiscal 1998, and collection of fundamental data has begun. With regard to the rinsing evaluation method, qualitative and quantitative analyses were performed on the rinsing by using a surface shape measuring microscope and the infrared spectroscopy. (NEDO)

  13. 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). 2nd year. Development of moisture respiration comfortable knitted fabrics using plasma processing; 1998 nendo plasma shori wo mochiita suibun kokyusei kaiteki oriamimono no kaihatsu seika hokokusho. 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    For the purpose of producing new textiles such as highly comfortable underwear of which sweaty/sticky/chilly feelings were controlled, study was conducted for the development of moisture respiration materials with durability by directly giving plasma-processing to knitted fabrics. In the study, project teams consisting of companies/universities/public testing institutes set their individual study targets. As to the optimization of the sizing agent for giving it the moisture respiration function, a method was found out in which plasma/graft polymerization processing to one side is made possible even without sizing agent coating. In relation to the optimization of materials, it was successful to give it the functional gradient by fabricating materials different in thickness by polyester fiber and by plasma/graft polymerization. Concerning the design/trial manufacture of large-area radiation use continuous atmospheric pressure glow discharge plasma processing device, it was confirmed that the processing can be made at almost uniform processing speed, 2cm/min. As to the design/trial manufacture of graft polymerization processing device, it was confirmed that the graft polymerization reaction progresses only on one side. (NEDO)

  14. 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

    Energy Technology Data Exchange (ETDEWEB)

    Yoshigoe, A.; Hirano, S. [The Graduate University for Advanced Studies, Yokohama (Japan); Mase, K.; Urisu, T. [Institute for Molecular Science, Aichi (Japan)

    1996-11-20

    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.

  15. 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

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, Y. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1998-07-25

    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.

  16. FY 1996 report on the results of the R and D of an implantable mechanical heart system using continuous flow pump; 1996 nendo tainai umekomigata shinzo system (rinshomae mansei dobutsu jikken) seika hokokusho gaiyoban. Renzokuryu pump wo mochiita tainai umekomigata shinzo system no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    As to a prototype polycarbonate miniature centrifugal pump (Gyro PI-601) of the primary trial fabrication, evaluation could be made on the efficiency, durability, anti-hemolyticity and anti-thrombogenicity also including animal experiments. Namely, as preliminary test on the efficiency and anti-thrombogenicity of Gyro PI-601, Gyro PI-601 as left ventricular assist was implanted into four calves for two weeks, and screening tests were conducted for the efficiency and anti-thrombogenicity. In all the examples, there were seen no thrombo-embolic symptoms during the term of implantation. Under the evaluation of the primary trial fabrication, the secondary trial pump fabrication (Gyro PI-701) was started using Ti alloys which is excellent in biological adaptability as materials of long-term implantable pump. The long-term implantable drive device which is corespondent to the implantable pump was evaluated also including animal experiments. Moreover, the primary trial fabrication was improved, and the secondary one could be obtained which is long-term implantable by efficiency improvement. The development could be commenced of the periphery technology of a totally implantable mechanical heart such as a data accumulation/analysis system and an extravascular passive mechanical emergency clamp, and the primary trial fabrication with high quality was achieved. (NEDO)

  17. Enhanced photoelectric conversion efficiency of dye sensitized solar cells via the incorporation of one dimensional luminescent BaWO4:Eu(3+) nanowires.

    Science.gov (United States)

    Wang, Yuping; Qu, Yang; Pan, Kai; Wang, Guofeng; Li, Yadong

    2016-09-25

    One dimensional hierarchical BaWO4:Eu(3+) nanowires have been prepared via a hydrothermal method for the first time. The obtained BaWO4:Eu(3+) nanowires are not only a promising down-conversion luminescence material, but also can be used to improve the efficiency of dye sensitized solar cells, resulting an efficiency of 7.66%, which is a noticeable enhancement of 15% compared to the cell without BaWO4:Eu(3+) nanowires. We suggest that the enhancement of the efficiencies of the TiO2-BaWO4:Eu(3+) composite cells was mainly related to the light scattering of BaWO4:Eu(3+).

  18. Electron microscopy analyses and electrical properties of the layered Bi{sub 2}WO{sub 6} phase

    Energy Technology Data Exchange (ETDEWEB)

    Taoufyq, A. [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université du Sud Toulon-Var, BP 20132, 83957, La Garde Cedex (France); Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir, Maroc (Morocco); Département d‘Études des Réacteurs, Laboratoire Dosimétrie Capteurs Instrumentation, CEA Cadarache (France); Société CESIGMA—Signals and Systems, 1576 Chemin de La Planquette, F 83 130 LA GARDE (France); Ait Ahsaine, H. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir, Maroc (Morocco); Patout, L. [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université du Sud Toulon-Var, BP 20132, 83957, La Garde Cedex (France); Benlhachemi, A.; Ezahri, M. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir, Maroc (Morocco); and others

    2013-07-15

    The bismuth tungstate Bi{sub 2}WO{sub 6} was synthesized using a classical coprecipitation method followed by a calcination process at different temperatures. The samples were characterized by X-ray diffraction, simultaneous thermogravimetry and differential thermal analysis (TGA/DTA), scanning and transmission electron microscopy (SEM, TEM) analyses. The Rietveld analysis and electron diffraction clearly confirmed the Pca2{sub 1} non centrosymmetric space group previously proposed for this phase. The layers Bi{sub 2}O{sub 2}{sup 2+} and WO{sub 4}{sup 2−} have been directly evidenced from the HRTEM images. The electrical properties of Bi{sub 2}WO{sub 6} compacted pellets systems were determined from electrical impedance spectrometry (EIS) and direct current (DC) analyses, under air and argon, between 350 and 700 °C. The direct current analyses showed that the conduction observed from EIS analyses was mainly ionic in this temperature range, with a small electronic contribution. Electrical change above the transition temperature of 660 °C is observed under air and argon atmospheres. The strong conductivity increase observed under argon is interpreted in terms of formation of additional oxygen vacancies coupled with electron conduction. - Graphical abstract: High resolution transmission electron microscopy: inverse fast Fourier transform giving the layered structure of the Bi{sub 2}WO{sub 6} phase, with a representation of the cell dimensions (b and c vectors). The Bi{sub 2}O{sub 2}{sup 2+} and WO{sub 4}{sup 2−} sandwiches are visible in the IFFT image. - Highlights: • Using transmission electron microscopy, we visualize the layered structure of Bi{sub 2}WO{sub 6}. • Electrical analyses under argon gas show some increase in conductivity. • The phase transition at 660 °C is evidenced from electrical modification.

  19. Influence of Morphology and Common Oxidants on the Photocatalytic Property of β-SnWO4 Nanoparticles.

    Science.gov (United States)

    Raj, Arguine Tes; Thangavel, Sakthivel; Rose, Aleena; Jipsa, C V; Jose, Meera; Nallamuthu, Gouthami; Kim, Sang-Jae; Venugopal, Gunasekaran

    2016-03-01

    In this paper, we report a simple, cost effective and surfactant-free method for synthesizing different morphology of β-SnWO4 with irregular, spherical, flake-like and leaf-like structures by using sonochemical method followed by calcination. A well dispersed and highly crystalline β-SnWO4 crystallites with various sizes have been prepared. The samples were characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM), UV-vis spectroscopy, particle size and Zeta potential analyser. The SEM images reveal the successful preparation of an irregular, spherical, flake-like and leaf-like structure of β-SnWO4. The absorption maximum of as-prepared different structures of β-SnWO4 was observed in visible region. The degradation efficiency was found to be increased in leaf-like structures compared to irregular, spherical and flake-like structures of β-SnWO4. Further, an enhanced photocatalytic effect was observed in leaf-like β-SnWO4 nanoparticles while the common oxidants such as peroxomonosulphate (PMS), peroxodisulphate (PDS) and hydrogen peroxide (H2O2) were added. The degradation efficiency of these oxidants was found in the order of PMS > H2O2 > PDS. Generally these oxidants act as electron scavengers. From our experimental results, it is found that maximum efficiency of 93% was achieved when PMS was added. This shows the vital role of common oxidants in photocatalytic characteristics and their future applications in waste-water treatment.

  20. Judd–Ofelt analysis of spectroscopic properties of Eu{sup 3+}:KLu(WO{sub 4}){sub 2} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Loiko, P.A. [Center for Optical Materials and Technologies, Belarusian National Technical University, 65/17 Nezavisimosti Ave., Minsk 220013 (Belarus); Dashkevich, V.I. [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68 Nezavisimosti Ave., Minsk 220072 (Belarus); Bagaev, S.N. [Institute of Laser Physics, Siberian Branch of Russian Academy of Sciences, 13/3 Lavrentyev Ave., Novosibirsk 630090 (Russian Federation); Orlovich, V.A. [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68 Nezavisimosti Ave., Minsk 220072 (Belarus); Mateos, X.; Serres, J.M. [Física i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcellí Domingo, s/n., Tarragona E-43007 (Spain); Vilejshikova, E.V.; Yasukevich, A.S. [Center for Optical Materials and Technologies, Belarusian National Technical University, 65/17 Nezavisimosti Ave., Minsk 220013 (Belarus); Yumashev, K.V., E-mail: k.yumashev@tut.by [Center for Optical Materials and Technologies, Belarusian National Technical University, 65/17 Nezavisimosti Ave., Minsk 220013 (Belarus); Kuleshov, N.V. [Center for Optical Materials and Technologies, Belarusian National Technical University, 65/17 Nezavisimosti Ave., Minsk 220013 (Belarus); Dunina, E.B.; Kornienko, A.A. [Vitebsk State Technological University, 72 Moskovskaya Ave., Vitebsk 210035 (Belarus); Vatnik, S.M. [Institute of Laser Physics, Siberian Branch of Russian Academy of Sciences, 13/3 Lavrentyev Ave., Novosibirsk 630090 (Russian Federation); Pavlyuk, A.A. [A.V. Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3 Lavrentyev Ave., Novosibirsk 630090 (Russian Federation)

    2015-12-15

    We report on a comprehensive spectroscopic study of monoclinic Eu:KLu(WO{sub 4}){sub 2} crystal concerning its potential applications in red lasers. Optical absorption and stimulated-emission cross-section spectra are determined for this crystal for the principal light polarizations, E || N{sub p}, N{sub m} and N{sub g}. The maximum σ{sub SE} corresponding to the {sup 5}D{sub 0}→{sup 7}F{sub 4} transition is 1.78×10{sup −20} cm{sup 2} at 703.5 nm (for E || N{sub m}). Spectroscopic properties of Eu:KLu(WO{sub 4}){sub 2} are modeled within the conventional Judd–Ofelt theory, as well as its modification for systems with an anomalously strong configuration interaction (ASCI), yielding absorption oscillator strengths, luminescence branching ratios for {sup 5}D{sub J}→{sup 7}F{sub J'} transitions and radiative lifetimes of the {sup 5}D{sub J} states. Photoluminescent properties of Eu:KLu(WO{sub 4}){sub 2} are studied under UV/visible excitation. Polarized Raman spectra are measured for Eu:KLu(WO{sub 4}){sub 2}. - Highlights: • Top-seeded solution growth of Eu:KLu(WO{sub 4}){sub 2} monoclinic crystal. • Modeling of spectroscopic parameters with modified Judd–Ofelt theory. • Polarization-resolved absorption and stimulated-emission cross-section spectra. • Maximum stimulated-emission cross-section is 1.78×10{sup −20} cm{sup 2} at 703.5 nm. • Polarized Raman spectroscopy of Eu:KLu(WO{sub 4}){sub 2} crystal.

  1. World Register of marine Cave Species (WoRCS: a new Thematic Species Database for marine and anchialine cave biodiversity

    Directory of Open Access Journals (Sweden)

    Vasilis Gerovasileiou

    2016-09-01

    Full Text Available Scientific exploration of marine cave environments and anchialine ecosystems over recent decades has led to outstanding discoveries of novel taxa, increasing our knowledge of biodiversity. However, biological research on underwater caves has taken place only in a few areas of the world and relevant information remains fragmented in isolated publications and databases. This fragmentation makes assessing the conservation status of marine cave species especially problematic, and this issue should be addressed urgently given the stresses resulting from planned and rampant development in the coastal zone worldwide. The goal of the World Register of marine Cave Species (WoRCS initiative is to create a comprehensive taxonomic and ecological database of known species from marine caves and anchialine systems worldwide and to present this as a Thematic Species Database (TSD of the World Register of marine Species (WoRMS. WoRCS will incorporate ecological data (e.g., type of environment, salinity regimes, and cave zone as well as geographical information on the distribution of species in cave and anchialine environments. Biodiversity data will be progressively assembled from individual database sources at regional, national or local levels, as well as from literature sources (estimate: >20,000 existing records of cave-dwelling species scattered in several databases. Information will be organized in the WoRCS database following a standard glossary based on existing terminology. Cave-related information will be managed by the WoRCS thematic editors with all data dynamically linked to WoRMS and its team of taxonomic editors. In order to mobilize data into global biogeographic databases, a Gazetteer of the Marine and Anchialine Caves of the World will be established. The presence records of species could be eventually georeferenced for submission to the Ocean Biogeographic Information System (OBIS and constitute an important dataset for biogeographical and

  2. WO.sub.3./sub. thin films prepared by sedimentation and plasma sputtering

    Czech Academy of Sciences Publication Activity Database

    Olejníček, Jiří; Brunclíková, Michaela; Kment, Š.; Hubička, Zdeněk; Kmentová, N.; Kšírová, Petra; Čada, Martin; Zlámal, M.; Krýsa, J.

    2017-01-01

    Roč. 318, Jun (2017), s. 281-288 ISSN 1385-8947 R&D Projects: GA TA ČR(CZ) TF01000084; GA ČR(CZ) GA15-00863S; GA TA ČR TA03010743; GA ČR GAP108/12/2104 Institutional support: RVO:68378271 Keywords : WO 3 * thin films * water splitting * pulsed magnetron sputtering * sedimentation * photo-electro-chemistry Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 6.216, year: 2016

  3. The system NaVO3-Na2WO4-Na2W2O7

    International Nuclear Information System (INIS)

    Kazanbekov, V.R.; Gasanaliev, A.M.; Kazanbekov, R.G.

    1994-01-01

    Phase diagrams of sodium metavanadate-sodium ditungstate, sodium metavanadate-sodium tungstate systems and surface of primary crystallization of sodium metavabadate-sodium tungstate-sodium ditungstate system were studied. The system sodium metavanadate-sodium ditungstate is eutectic one. Compound NaVO 3 x2Na 2 WO 4 is formed in solid state in sodium metavanadate-sodium tungstate system. Liquidus surface of sodium metavanadate-sodium tungstate-sodium ditungstate is presented by three crystallization fields of initial components. Composition and melting point of ternary eutectics are determined

  4. Write-once optical recording using WO2 films prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Aoki, Takanori; Matsushita, Tatsuhiko; Suzuki, Akio; Tanabe, Kenji; Okuda, Masahiro

    2006-01-01

    WO 2 films were deposited onto the glass substrates (Corning 7059 with an area of 26 x 38 mm) by the pulsed laser deposition method using an ArF excimer laser. It was found that after annealing at 500 deg. C for 10 min, the film thickness became 1.9 times compared with that (approximately 40 nm) in the as-deposited state. At that time, the difference in the transmittance, ΔT, between the annealed state and the as-deposited state was about 70% at the wavelength of 405 nm. From the XRD and XPS spectra, it was considered that oxygen was absorbed into the tungsten oxide films through the annealing process, accelerating the formation of WO 2 or WO 3 structure which caused the incremental effect in the transmittance and the expansion effect in the film thickness. For the revolution-test of the sample without the protection layer in which the WO 2 films were deposited upon the digital versatile disk (DVD-R) substrate, a write peak power dependence of CNR (at λ = 405 nm, NA = 0.65) of 3T signal (58.5 MHz) was measured at a linear velocity of 5 m/s and a read power of 0.6 mW. The values of CNR of 35 ∼ 40 dB were obtained at the peak power of 5 ∼ 7 mW, and increased largely up to 60 dB at 8 mW, and then reached a maximum of 62 dB at 8.5 mW. After that, the values of the CNR suffered some deterioration at more than 9 mW because of too much expansion of the written dot by which the portion between the dot and neighbor dots became to be invaded. For the dots formed in the writing performance on the DVD-R disk, the expansion effect in direction along the groove or over the neighboring lands was recognized by SEM images. It was found that bits of 0.18 ∼ 0.30 μm size, corresponding to the maximal storage capacity of 25 GB in the 'Blu-ray disk' specification, were made

  5. New self-frequency converted Nd3+:KGd(WO4)2 Raman lasers

    International Nuclear Information System (INIS)

    Ustimenko, N S; Gulin, A V

    2002-01-01

    The spatial orientation of the optical indicatrix axes in a nonlinear neodymium-doped potassium - gadolinium tungstate Nd 3+ :KGd (WO 4 ) 2 crystal is determined more exactly in experiments. Miniature Raman lasers of two types emitting at 1538 nm are built based on this crystal. The laser of the first type has an output energy of 5 - 7 mJ and a pulse repetition rate of up to 1 Hz, while the laser of the second type has an output energy of about 20 mJ and a pulse repetition rate of up to 20 Hz.

  6. New self-frequency converted Nd3+:KGd(WO4)2 Raman lasers

    Science.gov (United States)

    Ustimenko, N. S.; Gulin, A. V.

    2002-03-01

    The spatial orientation of the optical indicatrix axes in a nonlinear neodymium-doped potassium — gadolinium tungstate Nd3+:KGd (WO4)2 crystal is determined more exactly in experiments. Miniature Raman lasers of two types emitting at 1538 nm are built based on this crystal. The laser of the first type has an output energy of 5 — 7 mJ and a pulse repetition rate of up to 1 Hz, while the laser of the second type has an output energy of about 20 mJ and a pulse repetition rate of up to 20 Hz.

  7. PULSED KGd(WO42 RAMAN LASER: TOWARDS EMISSION LINEWIDTH NARROWING

    Directory of Open Access Journals (Sweden)

    V. G. Savitski

    2015-01-01

    Full Text Available The linewidth of a KGd(WO42 pulsed Raman laser is analysed experimentally for different configurations of the Raman and pump resonators: with narrow and broadband pump emission profiles, with and without linewidth narrowing elements in the Raman laser resonator, with and without injection seeding into the Raman cavity. The benefits of a narrow linewidth pump source in combination with linewidth narrowing elements in the Raman laser cavity for the efficient linewidth narrowing of the Raman emission are explained. 20 kW peak-power pulses at 1156 nm with 0,43 cm -1 emission linewidth are demonstrated from an injection seeded KGW Raman laser. 

  8. Comparative analysis of crystal-field parameters for rare-earth ions at monoclinic sites in AB(WO4)2 crystals: I. Tm3+ in KGd(WO4)2 and KLu(WO4)2, and Ho3+ and Er3+ ions in KGd(WO4)2

    International Nuclear Information System (INIS)

    Rudowicz, Czeslaw; Gnutek, Pawel

    2010-01-01

    The crystal-field (CF) parameters determined by various authors for rare-earth ions at monoclinic sites in AB(WO 4 ) 2 crystals are reanalyzed using a methodology incorporating several approaches, namely standardization, multiple-correlated fitting technique and closeness of CFP sets. In Part I recent spectroscopic data for Tm 3+ ions in KGd(WO 4 ) 2 (KGdW) and KLu(WO 4 ) 2 (KLuW), and Ho 3+ and Er 3+ ions in KGdW, which were interpreted using the free-ion (FI) and CF parameter (CFP) sets, are thoroughly revisited. Our reanalysis enables clarification of several doubtful aspects involved in the previous studies. The initial CFPs for fitting, calculated using the simple overlap model (SOM), differ markedly from the fitted CFPs for Tm 3+ ions in KGdW and KLuW. An inspection of the pertinent CFP sets reveals deeper intrinsic differences between the model and fitted CFPs. The model CFPs and the fitted CFPs for RE 3+ ions in both KGdW and KLuW crystals turn out to be non-standard. Importantly, the model and fitted CFP sets for Tm-KLuW belong to disparate regions of the CFP space and thus are intrinsically incompatible, i.e. such sets should not be directly compared. Thus the CFP sets reported in the literature require reconsideration in view of the intrinsic properties of monoclinic CF Hamiltonians previously not taken into account. Standardization of the originally non-standard CFP sets is carried out to ensure direct comparability of the CFP sets in question with other literature data. The correlated alternative CFP sets are calculated for each original set to facilitate future applications of the multiple correlated fitting technique, which enables improving overall reliability of the fitted CFPs. The closeness of the standardized CFP sets is assessed in a quantitative way. Our considerations indicate also the importance of proper definitions of the axis system used in the CFP model calculations and provide arguments for the nominal meaning of the axis systems

  9. The radiation induced colour centers in the NaBi(WO4)2 crystal

    International Nuclear Information System (INIS)

    Shi Hongsheng; Qin Laishun; Chai Wenxiang; Shu Kangying

    2009-01-01

    The radiation induced colour centers in the NaBi(WO 4 ) 2 crystals are investigated. The NBW crystals are irradiated by the Co 60 . The radiation doses are respectively the 10 4 , 10 5 and 10 6 rad and the corresponding dose rate respectively the 40, 2000 and 7000 rad/h. The maximum absorption wavelength of the radiation induced colour centers are identified at 460-470 nm. The mechanism of the formation of the colour centers is discussed. It is assumed that those colour centers are the F colour centers.

  10. Study of temperature dependence of light yield from NaBi(WO4)2 crystals

    International Nuclear Information System (INIS)

    Amosov, C.Yu.; Kalinin, B.N.; Krechetov, Yu.F.; Moiseenko, A.V.; Naumenko, G.A.; Potylitsin, A.P.; Sarytchev, V.P.; Shuvalov, Ye.N.; Vznuzdaev, Ye.A.; Samsonov, V.M.; Solodov, J.P.

    1994-01-01

    The scintillation time structure and the temperature dependence of the light yield from NaBi(WO 4 ) 2 crystals bombarded by 500 MeV electrons have been measured experimentally. These crystals showed a tendency to exhibit scintillator properties when the temperature of the samples was decreased. The light yield increased by more than an order of magnitude with the temperature falling from the room level to that of liquid nitrogen. The scintillation time structure was of a complex pattern, and a slow luminescent component (τ=30 ns) was present in the spectrum. ((orig.))

  11. Wpływ rozszerzenia Unii Europejskiej na stan rynku wołowiny w Polsce

    OpenAIRE

    Bąk-Filipek, Ewa

    2009-01-01

    The aim of this paper was to show the impact of the European Union’s enlargement on the status of beef market in Poland. The analysis was performed on the basis of data on cattle population and production of cattle live weight for years 2004-2008, changes in the retail trade sector in years 1991-2008 and prices for the period of 2004-2008. / Synopsis. Celem opracowania było wskazanie wpływu integracji z Unią Europejską na stan rynku wołowiny w Polsce. Analizę przeprowadzono w oparciu o dane d...

  12. Semiconducting WO.sub.3./sub. thin films prepared by pulsed reactive magnetron sputtering

    Czech Academy of Sciences Publication Activity Database

    Brunclíková, M.; Hubička, Zdeněk; Kment, Štěpán; Olejníček, Jiří; Čada, Martin; Kšírová, Petra; Krýsa, J.

    2015-01-01

    Roč. 41, č. 12 (2015), s. 9259-9266 ISSN 0922-6168. [Pannonian Symposium on Catalysis /12./. Třešť, 16.09.2014-20.09.2014] R&D Projects: GA ČR GAP108/12/2104; GA MŠk LH12043 Grant - others:AVČR(CZ) M100101215 Institutional support: RVO:68378271 Keywords : WO 3 * water splitting * HIPIMS * photoanodes Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.833, year: 2015

  13. Exfoliated thin Bi{sub 2}MoO{sub 6} nanosheets supported on WO{sub 3} electrode for enhanced photoelectrochemical water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ying; Jia, Yulong; Wang, Lina [State Key Laboratory for Oxo Synthesis & Selective Oxidation, and National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Min [State Key Laboratory for Oxo Synthesis & Selective Oxidation, and National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, CAS, Lanzhou 730000 (China); Bi, Yingpu, E-mail: yingpubi@licp.cas.cn [State Key Laboratory for Oxo Synthesis & Selective Oxidation, and National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, CAS, Lanzhou 730000 (China); Qi, Yanxing, E-mail: qiyx@licp.cas.cn [State Key Laboratory for Oxo Synthesis & Selective Oxidation, and National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, CAS, Lanzhou 730000 (China)

    2016-12-30

    Highlights: • Thin Bi{sub 2}MoO{sub 6} nanosheets were prepared by microwave assisted ultrasonic separation. • The thin Bi{sub 2}MoO{sub 6} nanosheets could be more favorable to charge shift and separation. • The WO{sub 3}/thin Bi{sub 2}MoO{sub 6} exhibits superior photoelectric activity than WO{sub 3}/Bi{sub 2}MoO{sub 6} film. • The efficient photoelectric property results from facilitated charge separation. - Abstract: Thin Bi{sub 2}MoO{sub 6} 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 Bi{sub 2}MoO{sub 6} supported on WO{sub 3} electrode (WO{sub 3}/thin Bi{sub 2}MoO{sub 6}) exhibits facilitated charge separation than pure WO{sub 3} film and the un-exfoliated Bi{sub 2}MoO{sub 6} nanosheets supported on WO{sub 3} electrode (WO{sub 3}/Bi{sub 2}MoO{sub 6}). As a result, WO{sub 3}/thin Bi{sub 2}MoO{sub 6} shows remarkably stable photocurrent density of 2.2 mA/cm{sup 2} at 0.8 V{sub SCE} in 0.1 M Na{sub 2}SO{sub 4} which is higher than that of that of WO{sub 3} (1.1 mA/cm{sup 2}) and WO{sub 3}/Bi{sub 2}MoO{sub 6} (1.5 mA/cm{sup 2}).

  14. Hierarchical Bi{sub 2}WO{sub 6} architectures decorated with Pd nanoparticles for enhanced visible-light-driven photocatalytic activities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinniu; Chen, Tianhua [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Lu, Hongbing, E-mail: hblu@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Yang, Zhibo; Yin, Feng; Gao, Jianzhi; Liu, Qianru [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Tu, Yafang [Department of Physics, Institute for Interdisciplinary Research, Jianghan University, Wuhan, 430056 (China)

    2017-05-15

    Highlights: • A new kind of Pd decorated Bi{sub 2}WO{sub 6} hierarchical microarchitecture was synthesized. • Pd nanoparticles remarkably improved the photocatalytic activity of Bi{sub 2}WO{sub 6}. • The photo-generated holes and ·O{sub 2}{sup −} played a crucial role in the degradation of RhB. • The photocatalytic enhancement mechanism of the Pd-Bi{sub 2}WO{sub 6} composites was proposed. - Abstract: A new kind of hierarchical Pd-Bi{sub 2}WO{sub 6} 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 Bi{sub 2}WO{sub 6} and Pd-Bi{sub 2}WO{sub 6} nanocatalyst were examined in the degradation of Rhodamine B (RhB) dyes and phenol under visible light. The photocatalytic results showed that the Pd-Bi{sub 2}WO{sub 6} nanocomposites possessed observably enhanced photocatalytic activities. Particularly, the 2.0% Pd loaded Bi{sub 2}WO{sub 6} 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{sup +}) and ·O{sub 2}{sup −} played a crucial role in the degradation of RhB. According to the experimental results, the photocatalytic degradation mechanism of Pd-Bi{sub 2}WO{sub 6} 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-Bi{sub 2}WO{sub 6} nanocomposites.

  15. Enhanced performance of direct Z-scheme CuS-WO 3 system towards photocatalytic decomposition of organic pollutants under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Song, Chundong; Wang, Xiang; Zhang, Jing; Chen, Xuebing; Li, Can

    2017-12-01

    CuS-WO3 composites were synthesized by an in situ solution method at low temperature. The crystalline phase, morphology, particle size, and the optical properties of CuS-WO3 samples were characterized by XRD, SEM, XPS, and UV–vis diffuse reflectance spectra. CuS-WO3 composites showed much higher activity for photocatalytic degradation of RhB as compared with WO3 and CuS. The degradation rate constant over 1 wt% CuS-WO3 catalyst was 4.4 times and 9.2 times higher than that of WO3 and CuS, respectively. It is found that holes (h+) and superoxide radical anions (O2-) are the dominant reactive species by using methanol, disodium ethylenediaminetetraacetate (EDTA) and ascorbic acid as scavengers. Band structure analysis shows that bottom of CB of WO3 is very similar with and higher (ca. 0.01 eV) than the top of VB of CuS. The results of PL showed that the similarity renders the recombination between photogenerated holes on the VB of CuS and photogenerated electrons on the CB of WO3 possible and easy, forming a direct Z-scheme in CuS-WO3. This result in that more electrons in the CB of CuS and holes in the VB of WO3 survived, and then participated in the photocatalytic degradation of RhB, showing an increased activity.

  16. UV-Vis optoelectronic properties of α-SnWO4: A comparative experimental and density functional theory based study

    KAUST Repository

    Ziani, Ahmed

    2015-09-03

    We report a combined experimental and theoretical study on the optoelectronic properties of α-SnWO4 for UV-Vis excitation. The experimentally measured values for thin films were systematically compared with high-accuracy density functional theory and density functional perturbation theory using the HSE06 functional. The α-SnWO4 material shows an indirect bandgap of 1.52 eV with high absorption coefficient in the visible-light range (>2 × 105 cm−1). The results show relatively high dielectric constant (>30) and weak diffusion properties (large effective masses) of excited carriers.

  17. Radioactive transitions in NaBi(MoO4)2x(WO4)2(1-x)

    International Nuclear Information System (INIS)

    Ehfendiev, Sh.M.; Darvishov, N.G.; Bobrova, E.Yu.

    1994-01-01

    Photoluminescence in new crystals with scheelite structure and their solid solutions NaBi(MoO 4 ) 2x (WO 4 ) 2(1-x) was studied. The spectra showed two luminescence bands- the blue and green ones in NaBi(WO 4 ) 2 , whereas in NaBi(MoO 4 ) 2 soley a green band was observed. In the solid solutions with an increase in component x the intensity of blue radiation excitation decreased, while the intensity of green radiation excitation did not change. 7 refs., 2 figs

  18. Photothermal ablation cancer therapy using homogeneous CsxWO3 nanorods with broad near-infra-red absorption

    Science.gov (United States)

    Guo, Chongshen; Yin, Shu; Yu, Haijun; Liu, Shaoqin; Dong, Qiang; Goto, Takehiro; Zhang, Zhiwen; Li, Yaping; Sato, Tsugio

    2013-06-01

    Recently, photothermal ablation therapy (PTA) employing near-infrared radiation (NIR) has been extensively investigated as an emerging modality for cancer management. However, the clinical translation of this promising approach is limited by the lack of PTA agents with broad NIR absorption, low cost and high photothermal conversion efficiency. Herein, we have developed PEGylated homogeneous CsxWO3 nanorods (a mean size ~69.3 nm × 12.8 nm) with broad photo-absorption (780-2500 nm) as a novel NIR absorbent for PTA treatment of human cancer. The prepared CsxWO3 nanocrystals displayed strong near-infrared optical absorption with a high molar extinction coefficient (e.g. 4.8 × 1010 M-1 cm-1 at 980 nm), thus generated significant amounts of heat upon excitation with near-infrared light. The PTA study in two human carcinoma cell lines (i.e. A549 lung cancer cells and HeLa ovarian cancer cells) demonstrated that CsxWO3 nanorods can efficiently cause cell death via hyperthermia induced lysosome destruction, cytoskeleton protein degradation, DNA damage and thereafter cellular necrosis or apoptosis. Our study also confirmed the migration of healthy cells migrated from unirradiated areas to dead cell cycle, which is essential for tissue reconstruction and wound healing after photodestruction of tumor tissue. The prompted results reported in the current study imply the promising potential of CsxWO3 nanorods for application in PTA cancer therapy.Recently, photothermal ablation therapy (PTA) employing near-infrared radiation (NIR) has been extensively investigated as an emerging modality for cancer management. However, the clinical translation of this promising approach is limited by the lack of PTA agents with broad NIR absorption, low cost and high photothermal conversion efficiency. Herein, we have developed PEGylated homogeneous CsxWO3 nanorods (a mean size ~69.3 nm × 12.8 nm) with broad photo-absorption (780-2500 nm) as a novel NIR absorbent for PTA treatment of human

  19. Renewable energy production by photoelectrochemical oxidation of organic wastes using WO{sub 3} photoanodes

    Energy Technology Data Exchange (ETDEWEB)

    Raptis, Dimitrios [Department of Chemical Engineering, University of Patras, 26500 Patras (Greece); Dracopoulos, Vassilios [FORTH/ICE-HT, P.O. Box 1414, 26504 Patras (Greece); Lianos, Panagiotis, E-mail: lianos@upatras.gr [Department of Chemical Engineering, University of Patras, 26500 Patras (Greece)

    2017-07-05

    Highlights: • Efficient nanoparticulate WO{sub 3} photoanodes. • Photoelectrocatalytic hydrogen production by consumption of organic wastes. • Photoelectrocatalytic oxidation of ethanol, glycerol or sorbitol. • Recording of hydrogen production and calculation of efficiencies. - Abstract: The present work has studied renewable hydrogen production by photoelectrocatalytic degradation of model organic substances representing biomass derived organic wastes. Its purpose was to show that renewable energy can be produced by consuming wastes. The study has been carried out by employing nanoparticulate WO{sub 3} photoanodes in the presence of ethanol, glycerol or sorbitol, i.e. three substances which are among typical biomass products. In these substances, the molecular weight and the number of hydroxyl groups increases from ethanol to sorbitol. The photocurrent produced by the cell was the highest in the presence of ethanol, smaller in the case of glycerol and further decreased in the presence of sorbitol. The photocurrent was roughly the double of that produced in the absence of an organic additive thus demonstrating current doubling phenomena. Hydrogen was produced only under illumination and was monitored at two forward bias, 0.8 and 1.6 V vs Ag/AgCl. Hydrogen production rates followed the same order as the photocurrent thus indicating that hydrogen production by reduction of protons mainly depends on the current flowing through the external circuit connecting photoanode with cathode. The maximum solar-to-hydrogen efficiency reached by the present system was 2.35%.

  20. Analysis of ferroelectric and magnetic chiral order in MnWO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Leo, Naemi; Meier, Dennis; Lottermoser, Thomas; Maringer, Michael; Fiebig, Manfred [HISKP, Universitaet Bonn (Germany); Becker, Petra; Bohaty, Ladislav [Institut fuer Kristallographie, Universitaet Koeln (Germany)

    2009-07-01

    Spin spiral systems form a particularly interesting subgroup of magnetoelectric multiferroics since violation of inversion symmetry by long-wavelength magnetic order is responsible for the spontaneous electric polarisation. Such intrinsic coupling of magnetism and ferroelectricity is not only promising with respect to future spintronic applications. It also enables fascinating physical effects like the magnetic-field-induced polarisation flop in TbMnO{sub 3} or MnWO{sub 4}. In our studies we focus on MnWO{sub 4}, which is a remarkable example of a spin-spiral multiferroic because a single transition-metal ion is responsible for the coexistence of magnetic and electric order. We present a spectral analysis of its multiferroic phase by means of optical second harmonic generation (SHG). With respect to symmetry dependent selection rules we distinguish between crystallographic, antiferromagnetic (AFM) and ferroelectric (FE) SHG contributions of different multipole order. Characteristic temperature dependencies of the associated FE and AFM order parameters further support the attribution.

  1. Topological magnetoelectric memory effect in the spin-spiral multiferroic MnWO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Meier, Dennis; Leo, Naemi; Lottermoser, Thomas; Fiebig, Manfred [HISKP, Universitaet Bonn (Germany); Becker, Petra; Bohaty, Ladislav [Institut fuer Kristallographie, Universitaet zu Koeln (Germany)

    2010-07-01

    Within the field of multiferroics, i.e. compounds with coexisting magnetic and electric order, so-called spin-spiral ferroelectrics attract tremendous attention. In these systems magnetic long-range order violates the inversion symmetry and induces a spontaneous electric polarization. Magnetic and electric domains are thus rigidly coupled so that ''giant'' magnetoelectric effects are obtained. However, up to now nearly nothing is know about the topology of the domain state in these systems. We report spatially-resolved measurements of the multiferroic domain topology in MnWO{sub 4}. For the first time, the full three-dimensional domain structure in a spin-spiral system is imaged. Our study reveals that the multiferroic domains in magnetically-induced ferroelectrics unify features that are associated to a magnetic domain state and others that point unambiguously to ferroelectric domains. Hence, a description in terms of ferroelectric or antiferromagnetic domains is incomplete and no longer appropriate. The novel concept of ''multiferroic hybrid domains'' is introduced. Annealing cycles reveal a topological memory effect: Due to phase coexistence at one phase boundary limiting the multiferroic state in MnWO{sub 4}, the entire multiferroic multidomain state can be reconstructed subsequent to quenching it.

  2. Neutron Powder Diffraction Studies of Ca2-xSrxCoWO6 Double Perovskites

    International Nuclear Information System (INIS)

    Zhou, Qingdi; Kennedy, Brendan; Elcombe, Margaret

    2005-01-01

    Full text: A series of double perovskite compounds of A 2-x Sr x CoWO 6 (A = Ca, Ba) were synthesized and the room- and variable-temperature structural phase transitions have been studied by synchrotron and neutron powder diffraction techniques. These studies demonstrated that the symmetry increases as the average size of the A-site cation increases. These transitions are associated with the gradual reduction and ultimately removal of the octahedral tiles of the BO 6 octahedra. Temperature dependent structural studies have been undertaken for selected samples. The transition to cubic is continuous in the three Ca doped samples studied as a function of temperature, Ca 2-x Sr x CoWO 6 x = 1.8, 1.7, 1.6, however in each case analysis of the spontaneous strain shows the transition to be tricritical rather than second order in nature. Where observed the temperature induced P2 1 /n to I4/m transition is first order as required by symmetry. (authors)>>>>

  3. Interfacing Photosynthetic Membrane Protein with Mesoporous WO3 Photoelectrode for Solar Water Oxidation.

    Science.gov (United States)

    Pang, Hong; Zhao, Guixia; Liu, Guigao; Zhang, Huabin; Hai, Xiao; Wang, Shengyao; Song, Hui; Ye, Jinhua

    2018-04-10

    Photosynthetic biocatalysts are emerging as a new class of materials, with their sophisticated and intricate structure, which promise improved remarkable quantum efficiency compared to conventional inorganic materials in artificial photosynthesis. To break the limitation of efficiency, the construction of bioconjugated photo-electrochemical conversion devices has garnered substantial interest and stood at the frontier of the multidisciplinary research between biology and chemistry. Herein, a biohybrid photoanode of a photosynthetic membrane protein (Photosystem II (PS II)), extracted from fresh spinach entrapped on mesoporous WO 3 film, is fabricated on fluorine-doped tin oxide. The PS II membrane proteins are observed to communicate with the WO 3 electrode in the absence of any soluble redox mediators and sacrificial reagents under the visible light of the solar spectrum, even to 700 nm. The biohybrid electrode undergoes electron transfer and generates a significantly enhanced photocurrent compared to previously reported PS II-based photoanodes with carbon nanostructures or other semiconductor substrates for solar water oxidation. The maximum incident photon-to-current conversion efficiency reaches 15.24% at 400 nm in the visible light region. This work provides some insights and possibilities into the efficient assembly of a future solar energy conversion system based on visible-light-responsive semiconductors and photosynthetic proteins. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Thickness control in electrophoretic deposition of WO3 nanofiber thin films for solar water splitting

    International Nuclear Information System (INIS)

    Fang, Yuanxing; Lee, Wei Cheat; Canciani, Giacomo E.; Draper, Thomas C.; Al-Bawi, Zainab F.; Bedi, Jasbir S.; Perry, Christopher C.; Chen, Qiao

    2015-01-01

    Graphical abstract: - Highlights: • A novel method combining electrospinning and electrophoretic deposition was established for the creation of nanostructured semiconductor thin films. • The created thin films displayed a high chemical stability with a controllable thickness. • The PEC water splitting performance of the thin films was optimized by fine-tuning the thickness of the films. • A maximum photoconversion efficiency was achieved by 18 μm nanofibrous thin films. - Abstract: Electrophoretic deposition (EPD) of ground electrospun WO 3 nanofibers was applied to create photoanodes with controlled morphology for the application of photoelectrochemical (PEC) water splitting. The correlations between deposition parameters and film thicknesses were investigated with theoretical models to precisely control the morphology of the nanostructured porous thin film. The photoconversion efficiency was further optimized as a function of film thickness. A maximum photoconversion efficiency of 0.924% from electrospun WO 3 nanofibers that EPD deposited on a substrate was achieved at a film thickness of 18 μm.

  5. Monolayered Bi2WO6 nanosheets mimicking heterojunction interface with open surfaces for photocatalysis

    Science.gov (United States)

    Zhou, Yangen; Zhang, Yongfan; Lin, Mousheng; Long, Jinlin; Zhang, Zizhong; Lin, Huaxiang; Wu, Jeffrey C.-S.; Wang, Xuxu

    2015-01-01

    Two-dimensional-layered heterojunctions have attracted extensive interest recently due to their exciting behaviours in electronic/optoelectronic devices as well as solar energy conversion systems. However, layered heterojunction materials, especially those made by stacking different monolayers together by strong chemical bonds rather than by weak van der Waal interactions, are still challenging to fabricate. Here the monolayer Bi2WO6 with a sandwich substructure of [BiO]+–[WO4]2−–[BiO]+ is reported. This material may be characterized as a layered heterojunction with different monolayer oxides held together by chemical bonds. Coordinatively unsaturated Bi atoms are present as active sites on the surface. On irradiation, holes are generated directly on the active surface layer and electrons in the middle layer, which leads to the outstanding performances of the monolayer material in solar energy conversion. Our work provides a general bottom-up route for designing and preparing novel monolayer materials with ultrafast charge separation and active surface. PMID:26359212

  6. Synthesis, Analysis, and Testing of BiOBr-Bi2WO6 Photocatalytic Heterojunction Semiconductors

    Directory of Open Access Journals (Sweden)

    Xiangchao Meng

    2015-01-01

    Full Text Available 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 significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%-Bi2WO6 composites were prepared under optimum synthesis conditions (120°C for 6 h and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation of Rhodamine B (RhB under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity.

  7. Photoluminescence and excited states dynamics in PbWO4:Pr3+ crystals

    CERN Document Server

    Auffray, E; Shalapska, T; Zazubovich, S

    2014-01-01

    Luminescence and photo-thermally stimulated defects creation processes are studied for a Pr3+-doped PbWO4 crystal at 4.2-400 K under excitation in the band-to-band, exciton, and charge-transfer transitions regions, as well as in the Pr3+-related absorption bands. Emission spectra of Pr3+ centers depend on the excitation energy, indicating the presence of Pr3+ centers of two types. The origin of these centers is discussed. The 2.03-2.06 eV emission, arising from the D-1(2) -> H-3(4) transitions of Pr3+ ions, is found to be effectively excited in a broad intense absorption band peaking at 4.2 K at 3.92 eV. By analogy with some other Pe(3+)-doped compounds, this band is suggested to arise from an electron transfer from an impurity Pr3+ ion to the crystal lattice W6+ or Pb2+ ions. The dynamics of the Pr3+-related excited states is clarified. In the PbWO4:Pr crystal studied, the concentration of single oxygen and lead vacancies as traps for electrons and holes is found to be negligible.

  8. Models of WO x films growth during pulsed laser deposition at elevated pressures of reactive gas

    Science.gov (United States)

    Gnedovets, A. G.; Fominski, V. Y.; Nevolin, V. N.; Romanov, R. I.; Fominski, D. V.; Soloviev, A. A.

    2017-12-01

    The films of tungsten oxides were prepared by pulsed laser ablation of W target in a reactive gas atmosphere (air of laboratory humidity). Optical analysis and ion signal measurements for the laser plume allowed to recognise a threshold gas pressure that suppresses the deposition of non-scattered atomic flux from the plume. When the pressure exceeds about 40 Pa, the films grow due to the deposition of species that could be formed in collisions of W atoms with reactive molecules (e.g., O2). Kinetic Monte Carlo method was used for modelling film growth. Comparison of the model structures with the experimentally prepared films has shown that the growth mechanism of ballistic deposition at a pressure of 40 Pa could be changed on the diffusion limited aggregation at a pressure of ~100 Pa. Thus, a cauliflower structure of the film transformed to a web-like structure. For good correlation of experimental and model structures of WO x , a dimension of structural elements in the model should coincide with W-O cluster size.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-09-01

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

  10. Formulation and evaluation of antisebum secretion effects of sea buckthorn w/o emulsion

    Directory of Open Access Journals (Sweden)

    Naveed Akhtar

    2010-01-01

    Full Text Available Purpose : This study was designed to formulate and evaluate the anti-sebum secretion effects of a topical skin-care cream (w/o emulsion of sea buckthorn versus its vehicle (Base as control. Materials and Methods : Concentrated sea buckthorn (H.rhamnoides fruit extract was entrapped in the inner aqueous phase of w/o emulsion. Base containing no extract and a Formulation containing 1% concentrated extract of H.rhamnoides was formulated. Lemon oil was incorporated to the odor. Both the Base and the Formulation were stored at different storage conditions for a period of 4 weeks to predict their stability. Different stability parameters i.e.; physical stability, centrifugation, and pH were monitored at different time intervals. Both the Base and the Formulation were applied to the cheeks of 10 healthy human volunteers (n=10 for a period of 8 weeks. Result : The expected organoleptic stability of creams was achieved from 4 weeks in-vitro study period. Odor disappeared with the passage of time due to volatilization of lemon oil. The pH of the Formulation showed significant ( P = 0.0002 decline due to high concentration of organic acids present in sea buckthorn. Similarly the Formulation showed statistically significant ( P < 0.05 effects on skin sebum secretion. Conclusion : The in vitro results showed a good stability over 4 weeks of observation period of both the Base and Formulation and the Formulation has anti sebum secretion effects over 8 weeks of observation period.

  11. Superior acidic catalytic activity and stability of Fe-doped HTaWO6 nanotubes

    KAUST Repository

    Liu, He

    2017-07-26

    Fe-doped HTaWO6 (H1-3xFexTaWO6, x = 0.23) nanotubes as highly active solid acid catalysts were prepared via an exfoliation-scrolling-exchange process. The specific surface area and pore volume of undoped nanotubes (20.8 m2 g-1, 0.057 cm3 g-1) were remarkably enhanced through Fe3+ ion-exchange (>100 m2 g-1, 0.547 cm3 g-1). Doping Fe ions into the nanotubes endowed them with improved thermal stability due to the stronger interaction between the intercalated Fe3+ ions and the host layers. This interaction also facilitated the preservation of effective Brønsted acid sites and the generation of new acid sites. The integration of these functional roles resulted in Fe-doped nanotubes with high acidic catalytic activities in the Friedel-Crafts alkylation of anisole and the esterification of acetic acid. Facile accessibility to active sites, generation of effective Brønsted acid sites, high stability of the tubular structure and strong acid sites were found to synergistically contribute to the excellent acidic catalytic efficiency. Additionally, the activity of cycled nanocatalysts can be easily recovered through annealing treatment.

  12. Hadron calorimeter performance with a PbWO4 EM compartment

    Energy Technology Data Exchange (ETDEWEB)

    Green, D.

    1996-01-01

    The CMS detector[1] at the LHC has chosen PbWO4 in order to achieve the superior photon energy resolution which is crucial in searching for the 2 photon decay of low mass Higgs bosons. The hadronic compartment is thought to be Cu absorber, since one is immersed in a 4 T magnetic field, read out by scintillator tiles coupled to wavelength shifter (WLS) fibers. The combined performance of this calorimeter is of interest in the study of jets and missing transverse energy (neutrino, SUSY signatures). For this reason, a test was made of the electromagnetic (EM) compartment combined with a reasonable approximation to the baseline HCAL ``barrel`` calorimeter. Data was taken in the H4 CERN beamline. The EM compartment was a 7 {times} 7 square array of PbWO4 crystals, which for the purposes of this study are considered as a single readout in depth (or ``compartment``) [2]. The HCAL module consisted of large scintillator plates with 24 individual longitudinal readout channels. The EM compartment was followed by 10 Cu plates each 3 cm thick, followed by 9 Cu plates each 6 cm thick. This set of absorber plates represented the HCAL compartments inside the coil. The coil itself [1] was approximated as Al and Fe plates, of a total thickness of about 1.4 absorption lengths. The coil mockup was sampled and then followed by 4 plates of 8 cm thick Cu, each with an individual readout which represented a test of the ``Tailcatcher`` concept.

  13. Recent developments in crystal calorimeters (featuring the CMS PbWO4 electromagnetic calorimeter)

    International Nuclear Information System (INIS)

    Gascon-Shotkin, S.

    2003-01-01

    In the mass range of 110-150 GeV the favored process for Higgs boson detection via p-p collisions is via its decay into two photons, which demands a very high-resolution electromagnetic calorimeter. This physics goal plus the Large Hadron Calorimeter (LHC)-imposed design constraints of 25ns bunch spacing and a hostile radiation environment have led the Compact Muon Solenoid (CMS) collaboration to the choice of lead tungstate (PbWO 4 ) crystals. These factors plus the presence of a 4T magnetic field and the relatively low room-temperature scintillation photon yield of PbWO 4 make photo detection a real challenge, which CMS has met via the choice of devices providing gain amplification: Avalanche photodiodes (APD) in the central barrel region and vacuum phototriodes (VPT) in the forward and backward endcap regions. In the past year the CMS electromagnetic calorimeter has entered the construction phase. We review progress in the areas of crystals, barrel and endcap photo detection devices, plans for detector calibration as well as the status of assembly and quality control. We also invoke relevant developments in other crystal calorimeters currently in operation or under development. Crystal calorimeters remain the medium of choice for precision energy and position measurements in high energy physics

  14. Construction and Nanoscale Detection of Interfacial Charge Transfer of Elegant Z-Scheme WO3/Au/In2S3 Nanowire Arrays.

    Science.gov (United States)

    Li, Haijin; Gao, Yuying; Zhou, Yong; Fan, Fengtao; Han, Qiutong; Xu, Qinfeng; Wang, Xiaoyong; Xiao, Min; Li, Can; Zou, Zhigang

    2016-09-14

    Elegant Z-scheme WO3/Au/In2S3 nanowire arrays were precisely constructed through a facile step-by-step route. Surface potential change on pristine or In2S3-Au coated WO3 single nanowire under dark and illumination detected through a Kelvin probe force microscopy (KPFM) technique indicates that the vectorial holes transfer of In2S3 → Au → WO3 should occur upon the excitation of both WO3 and In2S3. In such charge transfer processes, the embedded Au nanoparticles in the heterojunction systems act as a charge mediator for electrons in the conduction band of WO3 and holes in the valence band of In2S3. The strong charge carrier separation ability of this structure will finally enhance the oxidation ability of WO3 with high concertation of photogenerated holes and, further, leave the free electrons in the In2S3 with long surviving time. Therefore, the unique Z-scheme WO3/Au/In2S3 heterostructure shows great visible-light activity toward photocatalytic reduction of CO2 in the presence of water vapor into renewable hydrocarbon fuel (methane: CH4).

  15. Photocatalytic removal of gaseous nitrogen oxides using WO3/TiO2 particles under visible light irradiation: Effect of surface modification.

    Science.gov (United States)

    Mendoza, Joseph Albert; Lee, Dong Hoon; Kang, Joo-Hyon

    2017-09-01

    Photocatalytic nanoparticles have been receiving considerable attention for their potential use in many environmental management applications, including urban air quality control. This paper investigates the performance of surface modified WO 3 /TiO 2 composite particles in removing gaseous nitrogen oxides (NO x ) under visible light irradiation. The WO 3 /TiO 2 composite particles were synthesized using a modified wet chemical method with different concentrations of NaOH solution used as a surface modification agent for the host TiO 2 particles. The NO x removal efficiency of the WO 3 /TiO 2 particles was evaluated using a lab-scale continuous gas flow photo-reactor with a gas contact time of 1 min. Results showed that surface modification using NaOH can enhance the photocatalytic activity of the WO 3 /TiO 2 particles. The NO x removal efficiency of the surface modified WO 3 /TiO 2 was greater than 90%, while that of WO 3 /TiO 2 particles prepared by the conventional wet chemical method was ∼75%. The enhanced removal efficiency might be attributed to the formation of oxygen vacancies on the TiO 2 surface, providing sites for WO 3 particles to effectively bind with TiO 2 . However, excess amount of NaOH >3 M deteriorated the photocatalytic performance due to the increased agglomeration of the host TiO 2 particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Facile formation of Ag2WO4/AgX (X = Cl, Br, I) hybrid nanorods with enhanced visible-light-driven photoelectrochemical properties

    International Nuclear Information System (INIS)

    Li, Jingjing; Yu, Caiyun; Zheng, Changcheng; Etogo, Atangana; Xie, Yunlong; Zhong, Yijun; Hu, Yong

    2015-01-01

    Highlights: • Ag 2 WO 4 /AgX hybrid nanorods were prepared by a facile in-situ anion exchange reaction. • Ag 2 WO 4 nanorods and different X − ions were reacted in water at room temperature. • The hybrids possess significantly enhanced photoelectrochemical properties. • Ag 2 WO 4 /AgBr hybrids exhibit the highest photocatalytic activity among three samples. • The active species tests were also investigated to confirm photocatalytic mechanism. - Abstract: In this work, we demonstrated a general strategy for the preparation of a series of uniform Ag 2 WO 4 /AgX (X = Cl, Br, I) hybrid nanorods by a facile in-situ anion exchange reaction occurring at room temperature between pregrown Ag 2 WO 4 nanorods and different X − ions in water. Compared with Ag 2 WO 4 nanorods, further investigation has revealed that the as-prepared hybrid nanorods possess significantly enhanced photocurrent response and photocatalytic activity in degrading methyl orange (MO) under visible-light irradiation. In particular, the Ag 2 WO 4 /AgBr hybrid nanorods exhibit the highest photocatalytic activity among the three kinds of samples. The active species tests indicate that superoxide anion radicals and photogenerated holes are responsible for the enhanced photocatalytic performance

  17. CeO2/Bi2WO6Heterostructured Microsphere with Excellent Visible-light-driven Photocatalytic Performance for Degradation of Tetracycline Hydrochloride.

    Science.gov (United States)

    Zhang, Fengjun; Zou, Shuang; Wang, Tianye; Shi, Yuxi; Liu, Peng

    2017-10-01

    CeO 2 /Bi 2 WO 6 heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines was successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO 2 /Bi 2 WO 6 heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi 2 WO 6 in both the degradation of tetracycline hydrochloride (TCH) and rhodamine B (RhB) under visible-light irradiation. The 1CeO 2 /2Bi 2 WO 6 exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60 min reaction. The results suggested that the particular morphological conformation of the microspheres resulted in smaller size and more uniform morphology so as to increase the specific surface area. Meanwhile, the heterojunction was formed by coupling CeO 2 and Bi 2 WO 6 in the as-prepared microspheres, so that the separation efficiency of photogenerated electrons and holes was dramatically improved and the lifetimes of charge carriers were prolonged. Hence, introduction of CeO 2 could significantly enhance the photocatalytic activity of CeO 2 /Bi 2 WO 6 heterostructured microspheres and facilitate the degradation of TCH. This work provided not only a principle method to synthesize CeO 2 /Bi 2 WO 6 with the excellent photocatalytic performance for actual produce, but also a excellent property of the photocatalyst for potential application in photocatalytic treatment of tetracyclines wastewater from pharmaceutical factory. © 2017 The American Society of Photobiology.

  18. Fabrication of the heterostructured CsTaWO6/Au/g-C3N4 hybrid photocatalyst with enhanced performance of photocatalytic hydrogen production from water

    Science.gov (United States)

    Lang, Junyu; Liu, Mengqing; Su, Yiguo; Yan, Lijuan; Wang, Xiaojing

    2015-12-01

    In this work, a novel CsTaWO6/Au/g-C3N4 hybrid photocatalyst is successfully fabricated. The photocatalytic performance of the heterostructured CsTaWO6/Au/g-C3N4 composite was investigated. Au nanoparticles were photo-deposited as the interlayer between g-C3N4 and the surface of CsTaWO6, which can facilitate the photoinduced electrons migration as an electron-conduction bridge as well as increase visible-light absorption via the surface plasmon resonance. This heterostructured interface bridging by Au particles may significantly retard the recombination of electron-holes, which is beneficial to promote the photocatalytic activity under visible-light irradiation. It is found the CsTaWO6/Au/g-C3N4 sample showed excellent photocatalytic activity of water splitting, even higher than the sum of g-C3N4 and Au/CsTaWO6 samples, or the sum of CsTaWO6 and Au/g-C3N4 samples. It indicates that the heterostructured combination of g-C3N4 and CsTaWO6 bridging by Au particles provided the synergistic photocatalytic activity driving by solar light through an efficient electron transfer process.

  19. Controllable synthesis of Bi2WO6 nanoplate self-assembled hierarchical erythrocyte microspheres via a one-pot hydrothermal reaction with enhanced visible light photocatalytic activity

    Science.gov (United States)

    Yang, Zhenya; Huang, Lin; Xie, Yanyu; Lin, Zheguan; Fan, Yunyan; Liu, Dan; Chen, Lu; Zhang, Zizhong; Wang, Xuxu

    2017-05-01

    This work provides a simple approach of the F--assisted one-pot hydrothermal reaction to successfully synthesize Bi2WO6 hierarchical erythrocyte microspheres. The importance role of F- was systematically investigated by comparing different type of halogen ions, hydrothermal temperature and time. The possible growth mechanism of Bi2WO6 hierarchical structures was proposed. The hierarchical erythrocytes were formed through the well-ordered and oriented self-assembly of thin Bi2WO6 nanoplate primary subunits. F- ions were absorbed on Bi2WO6 nanoplate surface to suppress the nanoplate stack but to induce a self-assembly through the edge interaction of Bi2WO6 nanoplates into erythrocyte-like hierarchical microspheres superstructures. This erythrocyte structure narrowed the band gap energy and enhanced the visible-light photocatalytic activity of Bi2WO6. Moreover, superoxide radical anions and h+ were revealed as the main active species responding for the RhB degradation on Bi2WO6 under visible light irradiation.

  20. Abnormal network flow detection based on application execution patterns from Web of Things (WoT) platforms.

    Science.gov (United States)

    Yoon, Young; Jung, Hyunwoo; Lee, Hana

    2018-01-01

    In this paper, we present a research work on a novel methodology of identifying abnormal behaviors at the underlying network monitor layer during runtime based on the execution patterns of Web of Things (WoT) applications. An execution pattern of a WoT application is a sequence of profiled time delays between the invocations of involved Web services, and it can be obtained from WoT platforms. We convert the execution pattern to a time sequence of network flows that are generated when the WoT applications are executed. We consider such time sequences as a whitelist. This whitelist reflects the valid application execution patterns. At the network monitor layer, our applied RETE algorithm examines whether any given runtime sequence of network flow instances does not conform to the whitelist. Through this approach, it is possible to interpret a sequence of network flows with regard to application logic. Given such contextual information, we believe that the administrators can detect and reason about any abnormal behaviors more effectively. Our empirical evaluation shows that our RETE-based algorithm outperforms the baseline algorithm in terms of memory usage.

  1. Physical characteristic and irritation index of Syzigium aromaticum essential oil in O/W and W/O creams

    Science.gov (United States)

    Safriani, R.; Sugihartini, N.; Yuliani, S.

    2017-11-01

    Essential oil of Syzigium aromaticum has been formulated in O/W and W/O creams as anti-inflammatory dosage form. The purpose of this study was to evaluate the physical characteristic and irritation index of S. aromaticum essential oil in O/W and W/O creams. The creams were made by fusion method. The creams then were evaluated the physical characteristic including pH, viscosity, spreadability and adhesivity. The irritation index was obtained by irritation skin test in male rabbit. The results showed that the W/O and O/W creams have the value of pH: 6.3 and 6.27; spreadability: 3,18 and 4.17 cm2; adhesivity: 5.59 and 0.07 minutes; viscosity: 4.43 and 2.88 Pa.S, respectively. The irritation test showed that the control enhancer caused mild irritation in both of W/O and O/W creams. These findings indicated that type of cream might influence the physical characteristic and irritation index of S. aromaticum essential oil cream.

  2. Surface Structure and Photocatalytic Properties of Bi2WO6 Nanolatelets Modified by Molybdena Islands from Chemical Vapor Deposition

    NARCIS (Netherlands)

    Dittmer, A.; Menze, J.; Mei, Bastian Timo; Strunk, J.; Luftman, H.S.; Gutkowski, R.; Wachs, I.E.; Schuhmann, W.; Muhler, M.

    2016-01-01

    We report on a novel route of preparing molybdena-modified bismuth tungstates and their successful application in the photocatalytic oxygen evolution reaction and the oxidation of glycerol. Hierarchically assembled monocrystalline Bi2WO6 nanoplatelets with a specific surface area of 10 m2/g were

  3. The ternary system Na{sub 2}O-ZnO-WO{sub 3}: Compounds and phase relationships

    Energy Technology Data Exchange (ETDEWEB)

    Yan Fengbo; Chen Dagui; Li Wei; Lin Zhang; Zhao Zhenguo; Xue Liping [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Huang Feng [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)], E-mail: fhuang@fjirsm.ac.cn; Liang Jingkui [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080 (China); International Centre for Materials Physics, Chinese Academia Sinica, Shenyang 110016 (China)], E-mail: jkliang@aphy.iphy.ac.cn

    2008-06-30

    The subsolidus phase relationships of ternary system Na{sub 2}O-ZnO-WO{sub 3} have been investigated by X-ray diffraction (XRD) and differential thermal analyzer (DTA). All the samples were synthesized in the temperature range from 530 to 850 deg. C in air. There are one ternary compound and five binary compounds in the Na{sub 2}O-ZnO-WO{sub 3} system, which can be divided into eight three-phase regions. The crystal structure of the ternary compound Na{sub 3.6}Zn{sub 1.2}(WO{sub 4}){sub 3} is determined by single-crystal structure analysis method. It belongs to triclinic system with space group P1-bar and lattice constants a = 7.237 (5) A, b = 9.172 (6) A, c = 9.339 (6) A and {alpha} = 94.920 (4){sup o}, {beta} = 105.772 (9){sup o}, {gamma} = 103.531 (8){sup o}, Z = 2. DTA analyses indicate that the compound Na{sub 2}WO{sub 4} is not suitable to be the flux for ZnO crystal growth below 1250 deg. C, since no liquidus was observed in the system before 1250 deg. C.

  4. Alginate submicron beads prepared through w/o emulsification and gelation with CaCl2 nanoparticles

    NARCIS (Netherlands)

    Paques, J.P.; Linden, van der E.; Rijn, van C.J.M.; Sagis, L.M.C.

    2013-01-01

    A simple method for preparing gelled alginate beads with a diameter smaller than 5 µm is described. A 1% alginate solution and a medium chain triglyceride (MCT) oil are used to prepare a water-in-oil (w/o) emulsion, stabilized by polyglycerol polyricinoleate. CaCl2 nanoparticles with dimensions in

  5. Iron metabolism in BeWo chorion carcinoma cells. Transferrin-mediated uptake and release of iron

    NARCIS (Netherlands)

    van der Ende, A.; du Maine, A.; Simmons, C. F.; Schwartz, A. L.; Strous, G. J.

    1987-01-01

    Growing human choriocarcinoma BeWo b24 cells contain 1.5 X 10(6) functional cell surface transferrin binding sites and 2.0 X 10(6) intracellular binding sites. These cells rapidly accumulate iron at a rate of 360,000 iron atoms/min/cell. During iron uptake the transferrin and its receptor recycle at

  6. Electronic structure and magnetic properties of FeWO{sub 4} nanocrystals synthesized by the microwave-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, M.A.P. [INCTMN-DQ-Universidade Federal de Sao Carlos, Sao Carlos, P.O. Box 676, 13565-905, SP (Brazil); Cavalcante, L.S., E-mail: laeciosc@bol.com.br [INCTMN-Universidade Estadual, Paulista, P.O. Box 355, 14801-907, Araraquara, SP (Brazil); Morilla-Santos, C.; Filho, P.N. Lisboa [MAv-Universidade Estadual, Paulista, P.O. Box 473, 17033-360, Bauru, SP (Brazil); Beltran, A.; Andres, J.; Gracia, L. [Department de Quimica Fisica i Analitica, Universitat Jaume I, E-12071 Castello (Spain); Longo, E. [INCTMN-DQ-Universidade Federal de Sao Carlos, Sao Carlos, P.O. Box 676, 13565-905, SP (Brazil); INCTMN-Universidade Estadual, Paulista, P.O. Box 355, 14801-907, Araraquara, SP (Brazil)

    2012-11-15

    This communication reports that FeWO{sub 4} nanocrystals were successfully synthesized by the microwave-hydrothermal method at 443 K for 1 h. The structure and shape of these nanocrystals were characterized by X-ray diffraction, Rietveld refinement, and transmission electron microscopy. The experimental results and first principles calculations were combined to explain the electronic structure and magnetic properties. Experimental data were obtained by magnetization measurements for different applied magnetic fields. Theoretical calculations revealed that magnetic properties of FeWO{sub 4} nanocrystals can be assigned to two magnetic orderings with parallel or antiparallel spins in adjacent chains. These factors are crucial to understanding of competition between ferro- and antiferromagnetic behavior. Highlights: Black-Right-Pointing-Pointer Monophasic FeWO{sub 4} nanocrystals were synthesized by the microwave-hydrothermal method. Black-Right-Pointing-Pointer Rietveld refinement and clusters model for monoclinic structure Black-Right-Pointing-Pointer Magnetic properties of FeWO{sub 4} nanocrystals at different temperatures.

  7. Ag/AgCl Loaded Bi2WO6 Composite: A Plasmonic Z-Scheme Visible Light-Responsive Photocatalyst

    Directory of Open Access Journals (Sweden)

    Xiangchao Meng

    2016-01-01

    Full Text Available Hierarchical flower-like Bi2WO6 was successfully synthesized by facile hydrothermal method at low pH. And Ag/AgCl was loaded by photoreduction on its surface. As-prepared photocatalysts were characterized by various techniques. Bi2WO6 was successfully synthesized at a size of 2-3 μm. Depositing Ag/AgCl did not destroy the crystal structure, and both Ag+ and metallic Ag0 were found. The band gap of the composite was 2.57 eV, which indicates that visible light could be the activating irradiation. In the photocatalytic activity test, the composite with 10 wt% Ag/AgCl boasted the highest removal efficiency (almost 100% in 45 min. The significant enhancement can be attributed to the surface plasmon resonance (SPR effect and the establishment of heterostructures between Ag/AgCl and Bi2WO6. A possible mechanism of photocatalytic oxidation in the presence of Ag/AgCl-Bi2WO6 was proposed. This work sheds light on the potential applications of plasmonic metals in photocatalysis to enhance their activities.

  8. Fabrication of optical planar waveguides in KY(WO4)2 by He-ion implantation

    NARCIS (Netherlands)

    Borca, C.N.; Zäh, F.; Schnider, C.; Salathé, R.P.; Pollnau, Markus; Moretti, P.

    In this paper, planar waveguides produced by He-ion implantation have been demonstrated in undoped and Yb-doped KY(WO/sub 4/)/sub 2/ crystals. The effective refractive indices of guided modes in surface planar waveguides were measured by dark m-line spectroscopy and the refractive index profiles

  9. Photocatalytic ability of Bi6Ti3WO18 nanoparticles with a mix-layered Aurivillius structure

    Science.gov (United States)

    Mi, Longqing; Feng, Yongyi; Cao, Lei; Xue, Mingqiang; Qin, Chuanxiang; Huang, Yanlin; Qin, Lin; Seo, Hyo Jin

    2018-01-01

    Aurivillius phase layered perovskites Bi6Ti3WO18 was prepared by the sol-gel citrate-complexation synthesis. The sample developed into the plate-like nanoparticles with the exposed (001) facets. The phase formation and structure have been verified via X-ray polycrystalline powder diffraction (XRD) Rietveld refinements. The nanoparticles were investigated via the measurements such as FE-SEM, TEM, EDS, and the surface analyses. UV-Vis absorption data revealed that the Aurivillius compound has a direct band characteristic with the band energy of 2.214 eV. The band structure of Bi6Ti3WO18 nanoparticles was discussed on the base of the experiments and theoretical calculation. Bi3+-containing Aurivillius Bi6Ti3WO18 shows efficient photocatalytic degradation for rhodamine B dye (RhB) with the visible light irradiation ( λ > 420 nm). Dynamic characteristic of the light-created excitons was measured by the luminescence and decay lifetime. The multivalent properties of W and Ti ions in the Aurivillius-like lattices of Bi6Ti3WO18 photocatalyst were discussed.

  10. Low-temperature liquid phase epitaxy of rare-earth-ion doped KY(WO4)2 thin layers

    NARCIS (Netherlands)

    Romanyuk, Y.E.; Utke, I.; Ehrentraut, D.; Pollnau, Markus; Garcia-Revilla, S.; Valiente, R.; Kuleshov, N.V.

    2004-01-01

    Rare-earth-ion doped KY(WO4)2 (hereafter KYW) is a promising material for novel solid-state lasers. Low laser threshold, high efficiency, high output powers, and third-order nonlinear effects have stimulated research towards miniaturized thin-film waveguide lasers and amplifiers for future photonic

  11. Growth of Yb3+, Lu3+, Gd3+ co-doped KY(WO4)2 thin layers

    NARCIS (Netherlands)

    Aravazhi, S.; Geskus, D.; Pollnau, Markus; Worhoff, Kerstin; Agazzi, L.; Ismail, N.; Leijtens, X

    2008-01-01

    Rare-earth-ion-doped $KY(WO_4)_2 (KYW)$ is an important candidate for solid-state lasers. Its high refractive indices of the order of 2.0 make it attractive also for applications as integrated optical devices. Liquid phase epitaxy was employed for growing mono-crystalline KYW thin films co-doped

  12. Microwave assisted hydrothermal synthesis of Ag/AgCl/WO3 photocatalyst and its photocatalytic activity under simulated solar light

    International Nuclear Information System (INIS)

    Adhikari, Rajesh; Gyawali, Gobinda; Sekino, Tohru; Wohn Lee, Soo

    2013-01-01

    Simulated solar light responsive Ag/AgCl/WO 3 composite photocatalyst was synthesized by microwave assisted hydrothermal process. The synthesized powders were characterized by X-Ray Diffraction (XRD) spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), Diffuse Reflectance Spectroscopy (UV–Vis DRS), and BET surface area analyzer to investigate the crystal structure, morphology, chemical composition, optical properties and surface area of the composite photocatalyst. This photocatalyst exhibited higher photocatalytic activity for the degradation of rhodamine B under simulated solar light irradiation. Dye degradation efficiency of composite photocatalyst was found to be increased significantly as compared to that of the commercial WO 3 nanopowder. Increase in photocatalytic activity of the photocatalyst was explained on the basis of surface plasmon resonance (SPR) effect caused by the silver nanoparticles present in the composite photocatalyst. Highlights: ► Successful synthesis of Ag/AgCl/WO 3 nanocomposite. ► Photocatalytic experiment was performed under simulated solar light. ► Nanocomposite photocatalyst was very active as compared to WO 3 commercial powder. ► SPR effect due to Ag nanoparticles enhanced the photocatalytic activity.

  13. A mesoporous WO3−X/graphene composite as a high-performance Li-ion battery anode

    International Nuclear Information System (INIS)

    Liu, Fei; Kim, Jong Gu; Lee, Chul Wee; Im, Ji Sun

    2014-01-01

    Graphical abstract: The highly flexible and conductive graphene layer can enhance electron transfer, protect metal oxides against disintegration and aggregation and buffer the strain induced by volume expansion during cycles. The mesoporous surface layer provides an open network for Li+ diffusion. - Highlights: • Novel cocktail effects of 2D mesoporous WO 3−X /graphene for lithium ion battery. • New approach for lithium ion battery by easy and unique synthesis method. • Mechanism study with proper data for understanding a reaction on anode surface. - Abstract: A novel mesoporous WO 3−X /graphene composite was developed. This material allowed rapid electron and Li + ion diffusion when used as a Li-ion battery (LIB) anode material. Remarkably, the graphene support protected WO 3−X from changing volume during the electrochemical cycling process; this process generally induces capacity loss. The current work describes a high-performance anode material for LIB that has highly dense WO 3−X , as well as high capacity, rate capability and stability

  14. Thermal oxidation of seeds for the hydrothermal growth of WO{sub 3} nanorods on ITO glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Chai Yan [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Department of Mechanical and Material Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Abdul Razak, Khairunisak, E-mail: khairunisak@usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); NanoBiotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lockman, Zainovia, E-mail: zainovia@usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2015-11-30

    This work reports a simple seed formation method for the hydrothermal growth of tungsten oxide (WO{sub 3}) nanorods. A WO{sub 3} seed layer was prepared by thermal oxidation, where a W-sputtered substrate was heated and oxidized in a furnace. Oxidation temperatures and periods were varied at 400–550 °C and 5–60 min, respectively, to determine an appropriate seed layer for nanorod growth. Thermal oxidation at 500 °C for 15 min was found to produce a seed layer with sufficient crystallinity and good adhesion to the substrate. These properties prevented the seed from peeling off during the hydrothermal process, thereby allowing nanorod growth on the seed. The nanorod film showed better electrochromic behavior (higher current density of − 1.11 and + 0.65 mA cm{sup −2}) than compact film (lower current density of − 0.54 and + 0.28 mA cm{sup −2}). - Highlights: • A simple seed formation method (thermal oxidation) on sputtered W film is reported. • Crystalline seed with good adhesion to substrate is required for nanorod growth. • The appropriate temperature and period for seed formation were 500 °C and 15 min. • WO{sub 3} nanorods exhibited higher electrochromic current density than WO{sub 3} compact film.

  15. Resolution Properties of a Calcium Tungstate (CaWO4) Screen Coupled to a CMOS Imaging Detector

    Science.gov (United States)

    Koukou, Vaia; Martini, Niki; Valais, Ioannis; Bakas, Athanasios; Kalyvas, Nektarios; Lavdas, Eleftherios; Fountos, George; Kandarakis, Ioannis; Michail, Christos

    2017-11-01

    The aim of the current work was to assess the resolution properties of a calcium tungstate (CaWO4) screen (screen coating thickness: 50.09 mg/cm2, actual thickness: 167.2 μm) coupled to a high resolution complementary metal oxide semiconductor (CMOS) digital imaging sensor. A 2.7x3.6 cm2 CaWO4 sample was extracted from an Agfa Curix universal screen and was coupled directly with the active area of the active pixel sensor (APS) CMOS sensor. Experiments were performed following the new IEC 62220-1-1:2015 International Standard, using an RQA-5 beam quality. Resolution was assessed in terms of the Modulation Transfer Function (MTF), using the slanted-edge method. The CaWO4/CMOS detector configuration was found with linear response, in the exposure range under investigation. The final MTF was obtained through averaging the oversampled edge spread function (ESF), using a custom-made software developed by our team, according to the IEC 62220-1-1:2015. Considering the renewed interest in calcium tungstate for various applications, along with the resolution results of this work, CaWO4 could be also considered for use in X-ray imaging devices such as charged-coupled devices (CCD) and CMOS.

  16. Focused-ion-beam nano-structured rib channel waveguides in KY(WO4)2 for laser applications

    NARCIS (Netherlands)

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

    2006-01-01

    Bulk $KY(WO_4)_2$ (hereafter KYW) laser crystals doped with rare-earth ions are recognized to be among the most promising host materials for obtaining novel solid-state lasers. The rare-earth ions $RE^{3+}$ are easily incorporated in the KYW structure by replacing the $Y{3+}$ ions, resulting in a

  17. Growth, structural, electrical and optical properties of the thermally evaporated tungsten trioxide (WO{sub 3}) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Patel, K.J. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001, Gujarat (India); Panchal, C.J. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001, Gujarat (India)], E-mail: cjpanchal_msu@yahoo.com; Kheraj, V.A.; Desai, M.S. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001, Gujarat (India)

    2009-03-15

    Tungsten trioxide (WO{sub 3}) thin films are of great interest due to their enormous and promising applications in various opto-electronic thin-film devices. We have investigated the structural, electrical, and optical properties of the WO{sub 3} thin films grown by thermal evaporation of WO{sub 3} powder and their dependence on growth condition. The WO{sub 3} thin films were grown on glass substrates at different substrate temperature varying from room temperature to 510 deg. C. The structural characterization and surface morphology were carried out using X-ray diffraction and atomic force microscopy, respectively. The amorphous films were obtained at substrate temperatures below 450 deg. C whereas films grown above 450 deg. C were crystalline. The surface roughness and the grain size of the films increase on increasing the substrate temperature. The electrical characterization has been carried out using four-point-probe methods. The resistivity of the films decreases significantly while the carrier concentration and mobility increase with the substrate temperature. The transparency and optical energy band-gap, E{sub g}, of the films are found to decrease monotonically as the substrate temperature increases.

  18. Transdermal delivery of hydrophobic and hydrophilic local anesthetics from o/w and w/o Brij 97-based microemulsions

    DEFF Research Database (Denmark)

    Junyaprasert, Varaporn Buraphacheep; Boonme, Prapaporn; Songkro, Sarunyoo

    2007-01-01

    To characterize the physicochemical properties of drug-loaded oil-in-water (o/w) and water-in-oil (w/o) Brij 97-based microemulsions in comparison to their blank counterparts and to investigate the influence of microemulsion type on in vitro skin permeation of model hydrophobic drugs and their hy...

  19. Structural and photoluminescence behavior of thermally stable Eu3+activated CaWO4 nanophosphors via Li+ incorporation

    Science.gov (United States)

    Ramakrishna, P. V.; Lakshmana Rao, T.; Singh, Arvind; Benarji, B.; Dash, S.

    2017-12-01

    We have studied the structural and photo physical analogue of Eu3+ activated CaWO4 nanophosphors via Lithium (Li+ = 2, 5 7 and 10 at.%) ion incorporation. As-prepared (APS) samples were annealed at 900 °C to eliminate unwanted organic moieties present in the sample and to improve crystallinity. The samples are characterized employing X-ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), UV-VIS spectroscopy, photoluminescence studies and lifetime decay studies. FTIR features an absorption band at ∼832 cm-1, which correspond to its antisymmetric vibrations into Osbnd Wsbnd O band in the WO42- tetrahedron. CaWO4 having the scheelite type structure with C4h point group and I41/a space group. The surface morphology of the samples are studied with Scanning Electron Microscopy (SEM). Lithium Co-doped CaWO4:Eu3+ nanoparticles show red luminescence because of strong host contribution and different energy transfer rates from host to Eu3+ ions under 266 nm excitations. Lithium ion enhances the crystallinity and radiative transition rate thus results in higher emissive property. Calculated CIE co-ordinates of these Li+ doped 900 °C annealed samples under 266 nm excitation is x = 0.65 & y = 0.34, which are closer to the standard of NTSC (x = 0.67 & y = 0.33). This material may be potential candidates for white light emitting diodes.

  20. Scitillation characteristics of PbWO.sub.4./sub. single crystals doped with Th, Zr, Ce, Sb and Mn ions

    Czech Academy of Sciences Publication Activity Database

    Kobayashi, M.; Usuki, Y.; Ishii, M.; Senguttuvan, N.; Tanji, K.; Chiba, M.; Hara, K.; Nikl, Martin; Boháček, Pavel; Boccaro, S.

    2001-01-01

    Roč. 465, - (2001), s. 428-439 ISSN 0168-9002 R&D Projects: GA MŠk ME 159 Institutional research plan: CEZ:AV0Z1010914 Keywords : PbWO 4 * tetravalent-ion (Th 4 ) doping Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.026, year: 2001

  1. Photo- and thermally stimulated luminescence of non-stoichiometric undoped PbWO.sub.4./sub. crystals

    Czech Academy of Sciences Publication Activity Database

    Zazubovich, S.; Nikl, Martin

    2010-01-01

    Roč. 247, č. 2 (2010), s. 385-392 ISSN 0370-1972 Institutional research plan: CEZ:AV0Z10100521 Keywords : PbWO 4 * single crystal * nonstoichiometric * luminescence * defects Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.344, year: 2010

  2. Synthesis and characterization of WO 3 nanoparticles prepared by the precipitation method: Evaluation of photocatalytic activity under vis-irradiation

    Science.gov (United States)

    Martínez-de la Cruz, A.; Martínez, D. Sánchez; Cuéllar, E. López

    2010-01-01

    WO 3 nanoparticles were synthesized by the precipitation method varying the time employed in the formation of their precursor in aqueous media and the calcination temperature. The WO 3 crystallization process and morphology of the synthesized samples were followed by the XRD, TEM and SEM techniques. The effects of the calcination temperature on the surface area and optical properties of the WO 3 nanoparticles were also investigated. Nanoparticles with morphologies such as square and rectangular plates and ovoid forms were observed for the different experimental conditions. WO 3 nanoparticles with different morphologies were tested for the photocatalytic degradation of organic dyes. In general, the photocatalysts showed a capacity to bleach the dye solution in the following sequence: indigo carmine (IC) > rhodamine B (rhB) > congo red (CR). The extent of mineralization was determined by means of total organic carbon (TOC) measurements, which showed a satisfactory TOC reduction (93%, within 75 h) only for IC. This value was even better than the one concerning the P-25 Degussa reference.

  3. Improvement of optical properties and radiation hardness of NaBi(WO4)2 Cherenkov crystals

    International Nuclear Information System (INIS)

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

    2002-01-01

    On the basis of the data on melt evaporation while growing NaBi(WO 4 ) 2 Cherenkov crystals, the formation of nonstoichiometry and most probable types of dot defects of the crystals have been considered. The influence of melt nonstoichiometry and doping with Sc on optical transmission and radiation hardness of the crystals has been experimentally investigated. The surplus of WO 3 has been established to increase optical transmission and radiation hardness and lack of Bi 2 O 3 in the melt to reduce radiation hardness. Sc doping is shifting the absorption edge to UV region by 30-35 nm and is increasing radiation hardness of the crystals about three-fold. Analytical estimations give the increase of the number of Cherenkov photons by a factor of 1.3, which leads to an improvement of the energy resolution of a calorimeter based on NaBi(WO 4 ) 2 :Sc crystals compared with undoped NaBi(WO 4 ) 2 of approximately 15%

  4. Improvement of optical properties and radiation hardness of NaBi(WO sub 4) sub 2 Cherenkov crystals

    CERN Document Server

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

    2002-01-01

    On the basis of the data on melt evaporation while growing NaBi(WO sub 4) sub 2 Cherenkov crystals, the formation of nonstoichiometry and most probable types of dot defects of the crystals have been considered. The influence of melt nonstoichiometry and doping with Sc on optical transmission and radiation hardness of the crystals has been experimentally investigated. The surplus of WO sub 3 has been established to increase optical transmission and radiation hardness and lack of Bi sub 2 O sub 3 in the melt to reduce radiation hardness. Sc doping is shifting the absorption edge to UV region by 30-35 nm and is increasing radiation hardness of the crystals about three-fold. Analytical estimations give the increase of the number of Cherenkov photons by a factor of 1.3, which leads to an improvement of the energy resolution of a calorimeter based on NaBi(WO sub 4) sub 2 :Sc crystals compared with undoped NaBi(WO sub 4) sub 2 of approximately 15%.

  5. The effects of solvent on photocatalytic properties of Bi2WO6/TiO2 heterojunction under visible light irradiation

    Science.gov (United States)

    Guo, Qiyao; Huang, Yunfang; Xu, Hui; Luo, Dan; Huang, Feiyue; Gu, Lin; Wei, Yuelin; Zhao, Huang; Fan, Leqing; Wu, Jihuai

    2018-04-01

    Bi2WO6/TiO2 heterojunction photocatalysts with two different microstructures were controllably fabricated via a facile two-step synthetic route. XRD, XPS, SEM, TEM, BET-surface, DRS, PL spectra, photoelectrochemical measurement (Mott-Schottky), and zeta-potential analyzer were employed to clarify structural and morphological characteristics of the obtained products. The results showed that Bi2WO6 nanoparticles/nanosheets grew on the primary TiO2 nanorods. The TiO2 nanorods used as a synthetic template inhibit the growth of Bi2WO6 crystals along the c-axis, resulting in Bi2WO6/TiO2 heterostructure with one-dimensional (1D) morphology. The photocatalytic properties of Bi2WO6/TiO2 heterojunction photocatalysts were strongly dependent on their shapes and structures. Compared with bare Bi2WO6 and TiO2, Bi2WO6/TiO2 composite have stronger adsorption ability and better visible light photocatalytic activities towards organic dyes. The Bi2WO6/TiO2 composite prepared in EG solvent with optimal Bi:Ti ratio of 2:12 (S-TB2) showed the highest photocatalytic activity, which could totally decompose Rhodamine B within 10 min upon irradiation with visible light (λ > 422 nm), and retained the high photocatalytic performance after five recycles, confirming its stability and practical usability. The results of PL indicated that Bi2WO6 and TiO2 could combine well to form a heterojunction structure which facilitated electron-hole separation, and lead to the increasing photocatalytic activity.

  6. Global coordination and standardisation in marine biodiversity through the World Register of Marine Species (WoRMS and related databases.

    Directory of Open Access Journals (Sweden)

    Mark J Costello

    Full Text Available The World Register of Marine Species is an over 90% complete open-access inventory of all marine species names. Here we illustrate the scale of the problems with species names, synonyms, and their classification, and describe how WoRMS publishes online quality assured information on marine species. Within WoRMS, over 100 global, 12 regional and 4 thematic species databases are integrated with a common taxonomy. Over 240 editors from 133 institutions and 31 countries manage the content. To avoid duplication of effort, content is exchanged with 10 external databases. At present WoRMS contains 460,000 taxonomic names (from Kingdom to subspecies, 368,000 species level combinations of which 215,000 are currently accepted marine species names, and 26,000 related but non-marine species. Associated information includes 150,000 literature sources, 20,000 images, and locations of 44,000 specimens. Usage has grown linearly since its launch in 2007, with about 600,000 unique visitors to the website in 2011, and at least 90 organisations from 12 countries using WoRMS for their data management. By providing easy access to expert-validated content, WoRMS improves quality control in the use of species names, with consequent benefits to taxonomy, ecology, conservation and marine biodiversity research and management. The service manages information on species names that would otherwise be overly costly for individuals, and thus minimises errors in the application of nomenclature standards. WoRMS' content is expanding to include host-parasite relationships, additional literature sources, locations of specimens, images, distribution range, ecological, and biological data. Species are being categorised as introduced (alien, invasive, of conservation importance, and on other attributes. These developments have a multiplier effect on its potential as a resource for biodiversity research and management. As a consequence of WoRMS, we are witnessing improved

  7. Global Coordination and Standardisation in Marine Biodiversity through the World Register of Marine Species (WoRMS) and Related Databases

    Science.gov (United States)

    Bouchet, Philippe; Boxshall, Geoff; Fauchald, Kristian; Gordon, Dennis; Hoeksema, Bert W.; Poore, Gary C. B.; van Soest, Rob W. M.; Stöhr, Sabine; Walter, T. Chad; Vanhoorne, Bart; Decock, Wim

    2013-01-01

    The World Register of Marine Species is an over 90% complete open-access inventory of all marine species names. Here we illustrate the scale of the problems with species names, synonyms, and their classification, and describe how WoRMS publishes online quality assured information on marine species. Within WoRMS, over 100 global, 12 regional and 4 thematic species databases are integrated with a common taxonomy. Over 240 editors from 133 institutions and 31 countries manage the content. To avoid duplication of effort, content is exchanged with 10 external databases. At present WoRMS contains 460,000 taxonomic names (from Kingdom to subspecies), 368,000 species level combinations of which 215,000 are currently accepted marine species names, and 26,000 related but non-marine species. Associated information includes 150,000 literature sources, 20,000 images, and locations of 44,000 specimens. Usage has grown linearly since its launch in 2007, with about 600,000 unique visitors to the website in 2011, and at least 90 organisations from 12 countries using WoRMS for their data management. By providing easy access to expert-validated content, WoRMS improves quality control in the use of species names, with consequent benefits to taxonomy, ecology, conservation and marine biodiversity research and management. The service manages information on species names that would otherwise be overly costly for individuals, and thus minimises errors in the application of nomenclature standards. WoRMS' content is expanding to include host-parasite relationships, additional literature sources, locations of specimens, images, distribution range, ecological, and biological data. Species are being categorised as introduced (alien, invasive), of conservation importance, and on other attributes. These developments have a multiplier effect on its potential as a resource for biodiversity research and management. As a consequence of WoRMS, we are witnessing improved communication within the

  8. Anomalous ionic conductivity of Sc sub 2 (WO sub 4) sub 3 mediated by structural changes at high pressures and temperatures

    CERN Document Server

    Secco, R A; Imanaka, N; Adachi, G

    2002-01-01

    The ionic conductivity of Sc sub 2 (WO sub 4) sub 3 at 400 deg. C shows a normal decrease with increase in pressure up to 2.9 GPa but then increases anomalously at pressures up to 4.3 GPa. Synchrotron in situ x-ray diffraction results show that Sc sub 2 (WO sub 4) sub 3 undergoes pressure-induced amorphization at pressures coincident with the reversal in conductivity behaviour. The loss of crystal structure at high pressure may be associated with the property of negative thermal expansion in Sc sub 2 (WO sub 4) sub 3.

  9. Novel Bi2WO6-coupled Fe3O4Magnetic Photocatalysts: Preparation, Characterization and Photodegradation of Tetracycline Hydrochloride.

    Science.gov (United States)

    Wang, Tianye; Zhong, Shuang; Zou, Shuang; Jiang, Fuhuan; Feng, Limin; Su, Xiaosi

    2017-07-01

    Novel Bi 2 WO 6 -coupled Fe 3 O 4 magnetic photocatalysts with excellent and stable photocatalytic activity for degrading tetracycline hydrochloride and RhB were successfully synthesized via a facile solvothermal route. Through the characterization of the as-prepared magnetic photocatalysts by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra, it was found that the as-prepared magnetic photocatalysts were synthesized by the coupling of Bi 2 WO 6 and Fe 3 O 4 , and introduction of appropriated Fe 3 O 4 can improve nanospheres morphology and visible-light response. Among them, BFe2 (0.16% Fe 3 O 4 ) exhibited the best photocatalytic activity for degradation of tetracycline hydrochloride (TCH), reaching 81.53% after 90 min. Meanwhile, the as-prepared magnetic photocatalysts showed great separation and recycle property. Moreover, the results of electrochemical impedance spectroscopy demonstrated that the well conductivity of Fe 3 O 4 can promote photogenerated charge carriers transfer and inhibit recombination of electron-hole pairs, so that Bi 2 WO 6 /Fe 3 O 4 exhibited enhanced photocatalytic activity on degradation of TCH and RhB. Hence, this work provides a principle method to synthesize Bi 2 WO 6 /Fe 3 O 4 with excellent photocatalytic performance for actual application, in addition, it showed that introduction of Fe 3 O 4 not only can provide magnetism, but also can enhance photocatalytic activity of Bi 2 WO 6 /Fe 3 O 4 magnetic photocatalysts. © 2017 The American Society of Photobiology.

  10. Preparation of WO{sub 3}/g-C{sub 3}N{sub 4} composites and their application in oxidative desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Rongxiang, E-mail: zylhzrx@126.com; Li, Xiuping, E-mail: lilili_171717@126.com; Su, Jianxun; Gao, Xiaohan

    2017-01-15

    Highlights: • The WO{sub 3}/g-C{sub 3}N{sub 4} was successfully synthesized through simple calcination. • The process is simple and the cost raw materials is cheap. • The WO{sub 3}/g-C{sub 3}N{sub 4} firstly applied to ODS. • The desulpurization rate of WO{sub 3}/g-C{sub 3}N{sub 4} may attach to 91.2%. • Five recycles of WO{sub 3}/g-C{sub 3}N{sub 4} still attach to 89.5% due to heterogeneous catalysis. - Abstract: WO{sub 3}/graphitic carbon nitride (g-C{sub 3}N{sub 4}) composites were successfully synthesized through direct calcining of a mixture of WO{sub 3} and g-C{sub 3}N{sub 4} at 400 °C for 2 h. The WO{sub 3} was prepared by calcination of phosphotungstic acid at 550 °C for 4 h, and the g-C{sub 3}N{sub 4} was obtained by calcination of melamine at 520 °C for 4 h. The WO{sub 3}/g-C{sub 3}N{sub 4} 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 WO{sub 3}/g-C{sub 3}N{sub 4} composites exhibited stronger XRD peaks of WO{sub 3} and g-C{sub 3}N{sub 4} than the WO{sub 3} and pure g-C{sub 3}N{sub 4}. In addition, two WO{sub 3} peaks at 25.7° and 26.6° emerged for the 36% −WO{sub 3}/g-C{sub 3}N{sub 4} composite. This finding indicated that WO{sub 3} was highly dispersed on the surface of the g-C{sub 3}N{sub 4} nanosheets and interacted with the nanosheets, which resulted in the appearance of (012) and (022) planes of WO{sub 3}. The WO{sub 3}/g-C{sub 3}N{sub 4} composite also exhibited a larger specific surface area and higher degree of crystallization than WO{sub 3} or pure g-C{sub 3}N{sub 4}, 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.

  11. Structure and properties of TeO2-WO3 system glasses

    International Nuclear Information System (INIS)

    Kolobkov, V.P.; Ovcharenko, N.V.; Morozova, I.N.; Chebotarev, S.A.; Chikovskij, A.N.; Arkatova, T.G.

    1987-01-01

    Study of TeO 2 -WO 3 system is of interest for production of high-refractive-glasses with comparatively low crystallizability. Results of investigating some properties and structural features of this system glasses are presented. Composition and properties of studied glasses are presented. The properties were studied using the following techniques: the density was measured by hydrostatic weighing in toluene; thermal expansion coefficient was measured in quartz dilatometer DKV-5A; dilatometric temperature of glass softening (T g ) was defined as an intersection point of linear and curved parts of the plot of thermal expansion coefficient; refractive index (RI) - by immersion method; dielectric properties are measured. Consideration of vibronic spectra permits to conclude that in tungsten-tellurium glasses rare earth activator ions are arranged near tellurite and tungstate groupings proportional to glass-forming component content

  12. Neutron and X-ray difraction studies on the Bi2O3-WO3 system

    International Nuclear Information System (INIS)

    Zelada Silva, G.

    1984-01-01

    Different crystallographic phases of the (1-X) (Bi2O3) x (WO3) system were studied, with X in the range 0.12 0 C and then quenched on liquid nitrogen to freeze the high temperature structure. Another set of identical sampoes were slowly cooled to room temperature in order to abtain the equilibrium phase at this temperatutre. The X-ray data show good agreement whit published resiults, with the exception of a new phase appearting at room temperature instead of the σ phase, showing that the last is stable only at high temperatures. Neiutron diffraction refinements lead to an structural model with catins situated at ideal distributed between two different crystallographic sites: a) oxygen atoms shifted from the ideal site toward the direction, and b) interstitial oxygen atoms apart from the (1/2 1/2 1/2) intertice following the axis. (Author)

  13. TEM and AFM study of WO3 nanosize growth on α-Al2O3

    International Nuclear Information System (INIS)

    Al-Mohammad, A.

    2007-07-01

    WO 3 thin films have been deposited by thermal evaporation on (0001) and (1012 ) planes of alumina oxide single crystal and annealed either in Oxygen or in air atmosphere. The morphology and crystallographic structure of films (as-deposited and annealed films) have been characterized by Atomic Force Microscope (AFM), transmission electron microscope (TEM), and transmission electron diffraction (TED). During annealing, the films undergo important morphological and structural changes. The annealed films exhibit large grains. These grains have the monoclinic structure in epitaxial orientations. The grains are made of twinned microdomains elongated in the [100] direction resulting of a preferential growth. The microdomains are along the three different directions on the (0001) α-Al 2 O 3 surface and only one direction on the (1012 ) α-Al 2 O 3 one.(author)

  14. Preparation and characterisation of radiation hard PbWO4 crystal scintillator

    International Nuclear Information System (INIS)

    Sabharwal, S.C.; Desai, D.G.; Sangeeta; Karandikar, S.C.; Chauhan, A.K.; Sangiri, A.K.; Keshwani, K.S.; Ahuja, M.N.

    1996-01-01

    The selective loss of one of the crystal constituents is found to be responsible for the yellowish coloration of PbWO 4 crystals. However, using the already pulled crystals as the starting charge for the subsequent growth, colorless crystals can be grown. The crystals exhibiting excellent transmission characteristics have been grown employing a low temperature gradient, a moderate rotation rate of 15 rpm and a pull speed of 1 mm/h. The colored crystals show some radiation damage on gamma irradiation, while the colorless ones remain unaffected even for irradiation doses as high as 10 Mrad. Both the types of crystals show the presence of weak thermoluminescence (TL) emission when high irradiation doses (similar 10 Mrad) are given. Only one TL glow peak is obtained in both the cases but the peak temperatures are different. The emission centers responsible for the TL emission are found to be the ones which give rise to the scintillation emission in the crystal. (orig.)

  15. Gas Sensing Properties of Pure and Cr Activated WO3 Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    V. B. GAIKWAD

    2010-09-01

    Full Text Available Thick films of WO3 (Tungsten Oxide were prepared by screen-printing techniques. The surfaces of the films were modified by dipping them into an aqueous solution of Chromium Oxide (CrO3 for different intervals of time, followed by firing at 550 oC for 30 min. The gas sensing performance of the pure and Cr2O3-modified films was tested for various gases at different temperatures. The unmodified films showed response to H2S, ethanol and cigar smoke. However Cr2O3- modified films suppresses gas sensing response to all gases except H2S. The surface modification, using dipping process, altered the adsorbate-adsorbent interactions, which gave the specific selectivity and enhanced sensitivity to H2S gas. The gas response, selectivity, thermal stability and recovery time of the sensor were measured and presented. The role played by surface chromium species to improve gas sensing performance is discussed.

  16. Investigation the physicochemical properties and stability of w/o emulsion

    International Nuclear Information System (INIS)

    Iqbal, S.; Baloch, M.K.; Hameed, G.

    2014-01-01

    The study aims to investigate the stability of W/O emulsions with respect to coalescence time. The various concentrations of water were dispersed in oil phase (soybean oil). The compositions of organic and aqueous phases were varied by adding emulsifier (Monoglyceride), sodium chloride and thickening agent (mango's pulp). The technique employed for the mixing of two phases was homogenization. The Emulsion Stability Index (ESI), Viscosity changes, separation of organic and aqueous phases as a function of storage time have been studied. It has been found that monoglyceride increases the stability and decreases the emulsion stability index (ESI) and also decreases the viscosity changes with storage time while electrolytes and mango's pulp encourage the coalescence process and enhance the instability of the system. On the other hand the system that contained all the organic and aqueous ingredients showed high stability. (author)

  17. A pulsed single-frequency Nd:GGG/BaWO4 Raman laser

    Science.gov (United States)

    Liu, Zhaojun; Men, Shaojie; Cong, Zhenhua; Qin, Zengguang; Zhang, Xingyu; Zhang, Huaijin

    2018-04-01

    A single-frequency pulsed laser at 1178.3 nm was demonstrated in a crystalline Raman laser. A crystal combination of Nd:GGG and BaWO4 was selected to realize Raman conversion from a 1062.5 nm fundamental wave to a 1178.3 nm Stokes wave. An entangled cavity was specially designed to form an intracavity Raman configuration. Single-longitudinal-mode operation was realized by introducing two Fabry–Perot etalons into the Raman laser cavity. This laser operated at a pulse repetition rate of 50 Hz with 2 ms long envelopes containing micro pulses at a 30 kHz repetition rate. The highest output power was 41 mW with the micro pulse duration of 15 ns. The linewidth was measured to be less than 130 MHz.

  18. Synthesis and characterization of LnAg(WO{sub 4})(MoO{sub 4})

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Martinez, F. [Universidad Politecnica de Madrid, E.U.I.T. Industrial, Ronda de Valencia 3, 28012 Madrid (Spain)], E-mail: francisco.fernandezm@upm.es; Colon, C.; Montero, J.L.; Atanes, E. [Universidad Politecnica de Madrid, E.U.I.T. Industrial, Ronda de Valencia 3, 28012 Madrid (Spain); Rivero, C. [Universidad Politecnica de Madrid, E.T.S.I. Telecomunicaciones, Avda. Complutense s/n, Ciudad Universitaria, 28040 Madrid (Spain)

    2008-02-28

    Polycrystalline LnAg(WO{sub 4})(MoO{sub 4}) powders, with Ln = La to Lu and Y, have been obtained by ceramic method. Rietveld refinement for all compounds reveals that they present tetragonal symmetry, space group I4{sub 1}/a (No. 88), where the Ln{sup 3+}/Ag{sup +} ions are located in the 4a atomic positions, since the W/Mo are randomly distributed into 4b crystal sites. In these compounds, a and b lattice parameters take values between those corresponding to tungstate and molybdate compounds. A progressive decrease in the lattice parameters is observed in going from La to Lu derivatives as a consequence of the well-known lanthanide contraction.

  19. Further understanding of PbWO4 Scintillator characteristics and their optimisation. LUMEN activity in 1998

    CERN Document Server

    Baccaro, Stefania; Borgia, Bruno; Cecilia, Angelica; Dafinei, Ioan; Diemoz, Marcella; Fabeni, P; Festinesi, Armando; Longo, Egidio; Martini, M; Meinardi, F; Mihoková, E; Montecchi, Marco; Nikl, M; Pazzi, G P; Rosa, J; Sulc, Miroslav

    2000-01-01

    The aim of LUMEN collaboration was the investigation on single crystals of PbWO4 ( PWO): the results performed up to now provide the evidence of the possibility to optimise the optical properties of an intrinsic scintillator such as PWO. The control of essential requirements in the crystal preparation ( raw material purity, growing methods and post-growth annealing) as well as the introduction of selected dopants at suitable concentrations ( particularly trivalent and pentavalent ions) were found to be very successful in lowering the concentration of point defects in the lattice which strongly affect scintillation properties and radiation hardness. The systematic investigation effort to better understand the scintillation characteristics and to improve the quality of PWO crystals is due to their use for the CMS electromagnetic calorimeter.

  20. Cosmic ray calibration of the PbWO4 crystal electromagnetic calorimeter of CMS

    International Nuclear Information System (INIS)

    Franzoni, G.

    2006-01-01

    The Compact Muon Solenoid experiment at the CERN LHC features a high precision PbWO4 crystal electromagnetic calorimeter. Each crystal is first precalibrated with a radioactive source and by means of optical measurements. After the assembly, each supermodule (1700 crystals) is exposed to comics rays.The comparison between intercalibration obtained from cosmic muons and electrons from test beam was performed at the end of 2004 for an initial set of 130 channels and showed that a precalibration with a statistical precision of 1 to 2% can be achieved within approximately one week. An important aspect of the comics muons analysis is that it is entirely based on the calorimeter data, without using any external tracking device.We will present the setup and results from the 2004 test as well as recent data recorded on many supermodule

  1. Temperature dependence of structural parameters in the perovskite Na0.74WO3

    International Nuclear Information System (INIS)

    Darlington, C.N.W.; Hriljac, J.A.; Knight, K.S.

    2005-01-01

    Na x WO 3 undergoes three phase transitions involving tilting of the oxygen octahedra about left angle 100 right angle pseudocubic directions. We have measured the temperature dependence of the lattice parameters between 200 and 750 K - a temperature range that spans the three transitions - and determined the evolution of the structure within each phase as temperature changes. The experiments were performed on the high-resolution powder diffractometer HRPD, Rutherford Appleton Laboratory, UK, using time-of-flight neutron diffraction. The critical exponent that describes the temperature dependence of the total tilt angle has been evaluated. An unexpected change in the thermal expansion coefficient in the cubic phase is not understood: an argument based on Landau's theory of phase transitions is used to demonstrate that the change is not the result of co-existence of two phases. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Mapping residual stresses in PbWO$_{4}$ crystals using photo-elastic analysis

    CERN Document Server

    Lebeau, Michel; Majni, G; Paone, N; Pietroni, P; Rinaldi, D

    2005-01-01

    Large scintillating crystals are affected by internal stresses induced by the crystal growth temperature gradient remanence. Cutting boules (ingots) into finished crystal shapes allows for a partial tension relaxation but residual stresses remain the main cause of breaking. Quality control of residual stresses is essential in the application of Scintillating Crystals to high-energy physics calorimeters (e.g. CMS ECAL at CERN LHC). In this context the industrial process optimisation towards stress reduction is mandatory. We propose a fast technique for testing samples during the production process in order to evaluate the residual stress distribution after the first phases of mechanical processing. We mapped the stress distribution in PbWO/sub 4/slabs cut from the same production boule. The analysis technique is based on the stress intensity determination using the photo-elastic properties of the samples. The stress distribution is mapped in each sample. The analysis shows that there are regions of high residu...

  3. Separation of PbWO4 and BGO signals into Čerenkov and scintillation components

    Science.gov (United States)

    Voena, C.; DREAM Collaboration

    2009-04-01

    We present results from beam tests performed in 2007 on PbWO4 and BGO crystals in the context of the DREAM project. Signals from high energy electrons and pions are analyzed and the possibility of separating the contributions from Čerenkov (C) and scintillation (S) light for individual events is investigated. Different methods exploiting the difference in timing, in the spectra and in the directionality of the two types of light have been developed to determine the contribution of the two components. In the BGO crystal, Čerenkov signals have been enhanced with the use of optical filters and the ratio Č/S is measured with good precision (~20-30% for energy deposits less than 1 GeV).

  4. Study of the NaBi(WO4)2 Cerenkov calorimeter

    International Nuclear Information System (INIS)

    Mizuhashi, T.; Watanabe, H.; Ishibashi, S.

    2004-01-01

    A NaBi(WO 4 ) 2 crystal (NBW) is a most promising Cerenkov calorimeter as a photon detector due to its radiation-resistant property. We intend to adopt it as a photon-veto detector in beam-core region for the future rare Kaon decay experiment. However, there is no detail report regarding light yield, which is crucial parameter for our application. Then, a test-beam experiment using electrons and charged pions with momenta from 0.5 to 4.0 GeV/c in the π2 beam line at the 12-GeV PS of KEK was carried out. The light yield was measured to be 286 photoelectrons/GeV-deposition, which meets our requirement. In this report, properties of the NBW, a method and results of the test-beam experiment are presented. (author)

  5. Phase transition in sodium bismuth tungstate NaBi(WO4)2 - acoustic studies

    International Nuclear Information System (INIS)

    Khusravbekov, L.; Charnaya, E.V.; Tien, Cheng; Rakhimov, I.K.; Salakhutdinov, M.I.; Ulfatshoev, M.M.; Borisov, B.F.

    2008-01-01

    Acoustic studies of sodium bismuth tungstate, NaBi(WO 4 ) 2 , single crystal were carried out in the temperature range from 290 K to 340 K. Strong anomalies in ultrasound velocity and attenuation were observed above room temperature for both longitudinal and transverse waves. The results obtained suggested a phase transition at 319.2 K. The order parameter responsible for the phase transition was found to be coupled linearly with strains in transverse acoustic waves and nonlinearly with those in longitudinal waves. It was suggested that the phase transition is related with substitutional ordering of the Na + and Bi 3+ ions at the cation sites. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Polar Order and Frustrated Antiferromagnetism in Perovskite Pb2MnWO6 Single Crystals.

    Science.gov (United States)

    Ivanov, Sergey A; Bush, Alexander A; Stash, Adam I; Kamentsev, Konstantin E; Shkuratov, Valerii Ya; Kvashnin, Yaroslav O; Autieri, Carmine; Di Marco, Igor; Sanyal, Biplab; Eriksson, Olle; Nordblad, Per; Mathieu, Roland

    2016-03-21

    Single crystals of the multiferroic double-perovskite Pb2MnWO6 have been synthesized and their structural, thermal, magnetic and dielectric properties studied in detail. Pure perovskite-phase formation and stoichiometric chemical composition of the as-grown crystals are confirmed by X-ray single-crystal and powder diffraction techniques as well as energy-dispersive X-ray and inductively coupled plasma mass spectrometry. Detailed structural analyses reveal that the crystals experience a structural phase transition from the cubic space group (s.g.) Fm3̅m to an orthorhombic structure in s.g. Pn21a at about 460 K. Dielectric data suggest that a ferrielectric phase transition takes place at that same temperature, in contrast to earlier results on polycrystalline samples, which reported a transition to s.g. Pnma and an antiferroelectric low-temperature phase. Magnetic susceptibility measurements indicate that a frustrated antiferromagnetic phase emerges below 8 K. Density functional theory based calculations confirm that the cationic order between Mn and W is favorable. The lowest total energy was found for an antiferromagnetically ordered state. However, analyses of the calculated exchange parameters revealed strongly competing antiferromagnetic interactions. The large distance between the magnetic atoms, together with magnetic frustration, is shown to be the main reason for the low value of the ordering temperature observed experimentally. We discuss the structure-property relationships in Pb2MnWO6 and compare these observations to reported results on related Pb2BWO6 perovskites with different B cations.

  7. Solar photocatalytic activity of TiO{sub 2} modified with WO{sub 3} on the degradation of an organophosphorus pesticide

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Delgado, N.A. [Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, San Nicolás de los Garza, N.L. (Mexico); Gracia-Pinilla, M.A. [Universidad Autónoma de Nuevo León, Facultad de Ciencias Físico-Matemáticas, Av. Universidad, Cd. Universitaria, San Nicolás de los Garza, N.L. (Mexico); Universidad Autónoma de Nuevo León, Centro de Investigación e Innovación en Desarrollo de Ingeniería y Tecnología, PIIT Km 6, Carretera al Aeropuerto, Apodaca, N.L. (Mexico); Maya-Treviño, L.; Hinojosa-Reyes, L.; Guzman-Mar, J.L. [Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, San Nicolás de los Garza, N.L. (Mexico); Hernández-Ramírez, A., E-mail: aracely.hernandezrm@uanl.edu.mx [Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, San Nicolás de los Garza, N.L. (Mexico)

    2013-12-15

    Highlights: • TiO{sub 2} and WO{sub 3}/TiO{sub 2} (2 and 5%) were tested in the photocatalytic malathion degradation. • The use of solar radiation in the photocatalytic degradation process was evaluated. • Modified catalyst showed greater photocatalytic activity than pure TiO{sub 2}. • The mineralization rate was improved when WO{sub 3} content on TiO{sub 2} was 2%. -- Abstract: In this study, the solar photocatalytic activity (SPA) of WO{sub 3}/TiO{sub 2} photocatalysts synthesized by the sol–gel method with two different percentages of WO{sub 3} (2 and 5%wt) was evaluated using malathion as a model contaminant. For comparative purpose bare TiO{sub 2} was also prepared by sol–gel process. The powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, diffuse reflectance UV–vis spectroscopy (DRUV–vis), specific surface area by the BET method (SSA{sub BET}), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy with a high annular angle dark field detector (STEM-HAADF). The XRD, Raman, HRTEM and STEM-HAADF analyses indicated that WO{sub 3} was present as a monoclinic crystalline phase with nanometric cluster sizes (1.1 ± 0.1 nm for 2% WO{sub 3}/TiO{sub 2} and 1.35 ± 0.3 nm for 5% WO{sub 3}/TiO{sub 2}) and uniformly dispersed on the surface of TiO{sub 2}. The particle size of the materials was 19.4 ± 3.3 nm and 25.6 ± 3 nm for 2% and 5% WO{sub 3}/TiO{sub 2}, respectively. The SPA was evaluated on the degradation of commercial malathion pesticide using natural solar light. The 2% WO{sub 3}/TiO{sub 2} photocatalyst exhibited the best photocatalytic activity achieving 76% of total organic carbon (TOC) abatement after 300 min compared to the 5% WO{sub 3}/TiO{sub 2} and bare TiO{sub 2} photocatalysts, which achieved 28 and 47% mineralization, respectively. Finally, experiments were performed to assess 2% WO{sub 3}/TiO{sub 2} catalyst activity on

  8. Facile preparation of Z-scheme WO{sub 3}/g-C{sub 3}N{sub 4} composite photocatalyst with enhanced photocatalytic performance under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Lifeng, E-mail: lifeng.cui@gmail.com [School of Chemistry and Environmental Engineering, Dongguan University of Technology, Guangdong 523808 (China); Ding, Xiang; Wang, Yangang; Shi, Huancong; Huang, Lihua; Zuo, Yuanhui [Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Kang, Shifei, E-mail: sfkang@usst.edu.cn [Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China)

    2017-01-01

    Highlights: • WO{sub 3}/g-C{sub 3}N{sub 4} composites were synthesized through a facile mixing-and-heating method. • The composite showed improved visible light response. • The composite showed high activity for MB degradation. • Z-scheme charge carrier transfer pathways in the composite are proposed. - Abstract: Visible-light-driven WO{sub 3}/g-C{sub 3}N{sub 4} composites photocatalysts were synthesized via a facile one-step simultaneously heating procedure with urea as the main precursor. These prepared catalyst samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG), transmission electron microscopy (TEM), N{sub 2} adsorption, ultraviolet-visible diffuse reflection spectroscopy (UV–vis), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the WO{sub 3}/g-C{sub 3}N{sub 4} composites was evaluated by the photo-degradation of Rhodamine B (RhB) under visible light irradiation. The results indicated that the composites with 25 wt.% WO{sub 3} content exhibited highest photocatalytic activity compared to pure WO{sub 3}, bare g-C{sub 3}N{sub 4} and other WO{sub 3}/g-C{sub 3}N{sub 4} composites. The favorable photocatalytic activity of WO{sub 3}/g-C{sub 3}N{sub 4} composites was mainly attributed to the excellent surface properties, enhanced visible-light absorption and the desirable band positions. A possible Z-scheme photocatalytic mechanism was proposed based on structure and electrochemical characterizations results, which can well explain the enhanced migration rate of photogenerated electrons and holes in WO{sub 3}/g-C{sub 3}N{sub 4} heterojunctions.

  9. Low-temperature liquid-phase epitaxy and optical waveguiding of rare-earth-ion-doped KY(WO4)2 thin layers

    NARCIS (Netherlands)

    Romanyuk, Y.E.; Utke, I.; Ehrentraut, D.; Apostolopoulos, V.; Pollnau, Markus; Garcia-Revilla, S.; Valiente, B.

    2004-01-01

    Crystalline $KY(WO_{4})_{2}$ thin layers doped with different rare-earth ions were grown on b-oriented, undoped $KY(WO_{4})_{2}$ substrates by liquid-phase epitaxy employing a low-temperature flux. The ternary chloride mixture of NaCl, KCl, and CsCl with a melting point of 480°C was used as a

  10. A Preliminary Study on WO3‐Infiltrated W–Cu–ScYSZ Anodes for Low Temperature Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain; Reddy Sudireddy, Bhaskar; Høgh, Jens Valdemar Thorvald

    2012-01-01

    of symmetric cells were prepared by screen printing of WO3–CuO–ScYSZ ink and subsequent sintering at 1,300 °C for 1 h in 9% H2/N2. Analysis of the sintered backbone by X‐ray diffraction showed the metallic W and Cu phases. Precursor solutions of WO3 or CuO were infiltrated into porous WCS backbones to form...

  11. A novel nitrite biosensor based on the direct electron transfer hemoglobin immobilized in the WO{sub 3} nanowires with high length–diameter ratio

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui, E-mail: liuhui@sust.edu.cn; Duan, Congyue; Yang, Chenhui; Chen, Xianjin; Shen, Wanqiu; Zhu, Zhenfeng

    2015-08-01

    WO{sub 3} nanowires (WO{sub 3}NWs) with high length–diameter ratio have been synthesized through a simple synthetic route without any additive and then used to immobilize hemoglobin (Hb) to fabricate a mediator-free biosensor. The morphology and structure of WO{sub 3}NWs were characterized by scanning electron microscopy, transmission electronic microscopy and X-ray diffraction. Spectroscopic and electrochemical results revealed that WO{sub 3}NWs are an excellent immobilization matrix with biocompatibility for redox protein, affording good protein bioactivity and stability. Meanwhile, due to unique morphology and property of the WO{sub 3} nanowires, the direct electron transfer of Hb is facilitated and the prepared biosensors displayed good performance for the detection of nitrite with a wide linear range of 1 to 4200 μM, as well as an extremely low detection limit of 0.28 μM. The WO{sub 3} nanowires with high length–diameter ratio could be a promising matrix for the fabrication of mediator-free biosensors, and may find wide potential applications in environmental analysis and biomedical detection. - Highlights: • The WO{sub 3}NWs with high length–diameter ratio have been synthesized. • The WO{sub 3}NWs were used to immobilize Hb to fabricate a mediator-free biosensor. • The biosensor displays a wide linear range of 1–4200 μM for nitrite. • The biosensor exhibits an extremely low detection limit of 0.28 μM for nitrite.

  12. Cross-cultural adaptation of the Work Disability Diagnosis Interview (WoDDI for the Brazilian context Adaptación transcultural del Work Disability Diagnosis Interview (WoDDI para el contexto brasileño Adaptação transcultural do Work Disability Diagnosis Interview (WoDDI para o contexto brasileiro

    Directory of Open Access Journals (Sweden)

    Vivian Aline Mininel

    2012-02-01

    Full Text Available The Work Disability Diagnosis Interview (WoDDI is a structured interview guide developed by the University of Sherbrooke, Canada to help clinicians detect the most important work-related disability predictors and to identify one or more causes of prolonged absenteeism. This methodological study aims for the cross-cultural adaptation of the WoDDI for the Brazilian context. The method followed international guidelines for studies of this kind, including the following steps: initial translation, synthesis of translations, back translation, evaluation by an expert committee and testing of the penultimate version. These steps allowed obtaining conceptual, semantic, idiomatic, experiential and operational equivalences, in addition to content validity. The results showed that the translated WoDDI is adapted to the Brazilian context and can be used after training.El Work Disability Diagnosis Interview (WoDDI es una guía de entrevista estructurada desarrollada por la Universidad de Sherbrooke (Canadá, para ayudar a los profesionales de la salud a detectar los predictores de mayor importancia para personas con trastornos relacionados con el trabajo y para identificar una o más causas de ausentismo prolongado del trabajo. Este estudio metodológico se dirige a la adaptación transcultural (WoDDI para el contexto brasileño. El método siguió las recomendaciones internacionales para este tipo de estudio, el que comprende las siguientes etapas: traducción inicial, síntesis de las traducciones, retraducción, revisión del comité de expertos y prueba de la versión pre-final. Estas medidas permitieron obtener la equivalencia conceptual, semántica, idiomática y la experiencia operacional, además de la validación del contenido. Los resultados mostraron que el WoDDI traducido se adapta a la realidad brasileña e puede ser utilizado, después de la capacitación previa.O Work Disability Diagnosis Interview (WoDDI é um guia de entrevista estruturada

  13. Fabrication of WO3@g-C3N4 with core@shell nanostructure for enhanced photocatalytic degradation activity under visible light

    Science.gov (United States)

    Wang, Pu; Lu, Na; Su, Yan; Liu, Ning; Yu, Hongtao; Li, Jie; Wu, Yan

    2017-11-01

    WO3@g-C3N4 composite photocatalysts with core@shell nanostructure were fabricated via a self-assembly method. A large heterojunction interfacial area of WO3@g-C3N4 can be provided in the nanoscale heterostructure. Furthermore, the electron mobility of the composite photocatalysts was improved with the introduction of WO3. These are favorable for increasing the separation efficiency of photoinduced electron-hole pairs and improving the photocatalytic efficiency of WO3@g-C3N4, which was confirmed by the measurements of photocurrent and electrochemical impedance spectroscopy. The results of the photocatalytic degradation of Rh B showed dramatic photocatalytic performance of this composite photocatalyst. The kinetic constant of Rh B degradation on the WO3@g-C3N4 was 0.95 h-1, which was 7.7-fold and 3.5-fold higher than those on pure WO3 and g-C3N4 nanosheets, respectively. In addition, the stability of the composite photocatalyst was also satisfactory according to the result of the three-cycle experiment.

  14. Sonochemical degradation of methyl orange in the presence of Bi2WO6: Effect of operating parameters and the generated reactive oxygen species.

    Science.gov (United States)

    He, Ling-Ling; Liu, Xian-Ping; Wang, Yong-Xia; Wang, Zhi-Xin; Yang, Yan-Jie; Gao, Yan-Ping; Liu, Bin; Wang, Xin

    2016-11-01

    The Bi2WO6 was prepared by the hydrothermal method and its sonocatalytic activity was studied in the degradation of methyl orange (MO) solutions. The effects of catalytic activity of Bi2WO6 on dye were inspected by the change in absorbance of dye with UV-vis spectrometer. The influences of operational parameters such as the addition amount of Bi2WO6, pH, the initial concentration of dyes, ultrasonic power and irradiation time on the degradation ratio were investigated. In addition, the obtained results indicated that the kinetics of sonochemical reactions of MO were consistent with the pseudo first-order kinetics and Bi2WO6 had excellent reusability and stability during the sonochemical degradation processes. The generation and kinds of reactive oxygen species (ROS) and their influence on the sonochemical degradation of MO were determined by the methods of oxidation-extraction spectrophotometry and ROS scavengers. The results indicate that the degradation of MO in the presence of Bi2WO6 under ultrasonic irradiation is related to the generation of ROS, in which both singlet molecular oxygen ((1)O2) and hydroxyl radical (OH) play important roles in the sonochemical degradation of MO. These experimental results provide a sound foundation for the further development of Bi2WO6 as a sonocatalyst in wastewater treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Synthesis of γ-WO{sub 3} thin films by hot wire-CVD and investigation of its humidity sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Jadkar, Vijaya; Waykar, Ravindra; Jadhavar, Ashok [School of Energy Studies, Savitribai Phule Pune University, Pune 411 007 (India); Pawbake, Amit [School of Energy Studies, Savitribai Phule Pune University, Pune 411 007 (India); Physical and Material Chemistry Division, National Chemical Laboratory, Pune 411 008 (India); Date, Abhijit [School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Plenty Road, Bundoora, Melbourne VIC 3083 (Australia); Late, Dattatray [Physical and Material Chemistry Division, National Chemical Laboratory, Pune 411 008 (India); Pathan, Habib; Gosavi, Suresh; Jadkar, Sandesh [Department of Physics, Savitribai Phule Pune University, Pune 411 007 (India)

    2017-05-15

    In this study, monoclinic tungsten oxide (γ-WO{sub 3}) have been grown in a single step using HW-CVD method by resistively heating W filaments in a constant O{sub 2} pressure. The formation of γ-WO{sub 3} was confirmed using low angle-XRD and Raman spectroscopy analysis. Low angle-XRD analysis revealed that as-deposited WO{sub 3} film are highly crystalline and the crystallites have preferred orientation along the (002) direction. HRTEM analysis and SAED pattern also show the highly crystalline nature of WO{sub 3} with d spacing of ∝ 0.38 nm, having an orientation along the (002) direction. Surface topography investigated by SEM analysis shows the formation of a uniform and homogeneous cauliflower like morphology throughout the substrate surface without flaws and cracks. A humidity sensing device incorporating WO{sub 3} is also fabricated, which shows a maximum humidity sensitivity factor of ∝ 3954% along with a response time of ∝14 s and a recovery time of ∝25 s. The obtained results demonstrate that it is possible to synthesize WO{sub 3} in a single step by HW-CVD method and to fabricate a humidity sensor by using it. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Structural, vibrational, and gasochromic properties of porous WO sub 3 films templated with a sol-gel organic-inorganic hybrid

    CERN Document Server

    Opara-Krasovec, U; Orel, B; Grdadolnik, J; Drazic, G

    2002-01-01

    The structure and the gasochromic properties of sol-gel-derived WO sub 3 films with a monoclinic structure (m-WO sub 3) were studied by focusing attention on the size of the monoclinic grains. The size of the m-WO sub 3 grains is modified by the addition of an organic-inorganic hybrid to the initial peroxopolytungstic acid (W-PTA) sols which are based on chemically bonded poly-(propylene glycol) to triethoxysilane end-capping groups (ICS-PPG). The results obtained with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that the heat treatment (500 sup o C) of WO sub 3 /ICS- IPG (0.5, 1, 2, 5, and 10 mol%) composite films results in a change of their morphology, and nanodimensional pores are formed between the grains. High-resolution TEM (HRTEM) analysis revealed the presence of an amorphous phase on the outside of the m-WO sub 3 grains, whereas energy-dispersive x-ray spectra (EDXS) showed that this amorphous phase contained W and Si. Impregnation of the WO sub 3 /ICS-PPG film ...

  17. Synthesis, characterization and photocatalytic activity of WO{sub 3}/TiO{sub 2} for NO removal under UV and visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Luévano-Hipólito, E. [CIIDIT, Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Martínez-de la Cruz, A., E-mail: azael.martinezdl@uanl.edu.mx [CIIDIT, Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); López-Cuellar, E. [CIIDIT, Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Yu, Q.L.; Brouwers, H.J.H. [Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2014-11-14

    Samples with different proportions WO{sub 3}/TiO{sub 2} were prepared by co-precipitation method followed by a heat treatment. The samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), and adsorption–desorption N{sub 2} isotherms (BET). The photocatalytic properties of WO{sub 3}/TiO{sub 2} samples were evaluated in the photo-oxidation reaction of nitric oxide (NO) under UV and visible light irradiation. The highest photocatalytic activity was observed in the WO{sub 3}/TiO{sub 2} sample with a composition of 80% mole of TiO{sub 2}. Among the different substrates used for supporting the photocatalyst, the best results were reached over concrete and glass when it was exposed to UV and visible light irradiation, respectively. In overall, the photocatalytic efficiency of the synthesized materials was higher under UV than visible light irradiation. - Highlights: • WO{sub 3}/TiO{sub 2} prepared in simple way show high photocatalytic activity for NO removal. • The concrete was the best substrate to the performance of WO{sub 3}/TiO{sub 2} with UV radiation. • The glass was the best substrate to the performance of WO{sub 3}/TiO{sub 2} with visible radiation.

  18. Highly Efficient Electronic Sensitization of Non-oxidized Graphene Flakes on Controlled Pore-loaded WO3 Nanofibers for Selective Detection of H2S Molecules

    Science.gov (United States)

    Choi, Seon–Jin; Choi, Chanyong; Kim, Sang-Joon; Cho, Hee-Jin; Hakim, Meggie; Jeon, Seokwoo; Kim, Il–Doo

    2015-01-01

    Tailoring of semiconducting metal oxide nanostructures, which possess controlled pore size and concentration, is of great value to accurately detect various volatile organic compounds in exhaled breath, which act as potential biomarkers for many health conditions. In this work, we have developed a very simple and robust route for controlling both the size and distribution of spherical pores in electrospun WO3 nanofibers (NFs) via a sacrificial templating route using polystyrene colloids with different diameters (200 nm and 500 nm). A tentacle-like structure with randomly distributed pores on the surface of electrospun WO3 NFs were achieved, which exhibited improved surface area as well as porosity. Porous WO3 NFs with enhanced surface area exhibited high gas response (Rair/Rgas = 43.1 at 5 ppm) towards small and light H2S molecules. In contrast, porous WO3 NFs with maximized pore diameter showed a high response (Rair/Rgas = 2.8 at 5 ppm) towards large and heavy acetone molecules. Further enhanced sensing performance (Rair/Rgas = 65.6 at 5 ppm H2S) was achieved by functionalizing porous WO3 NFs with 0.1 wt% non-oxidized graphene (NOGR) flakes by forming a Schottky barrier (ΔΦ = 0.11) at the junction between the WO3 NFs (Φ = 4.56 eV) and NOGR flakes (Φ = 4.67 eV), which showed high potential for the diagnosis of halitosis.

  19. Highly efficient perovskite solar cells based on a nanostructured WO3-TiO2 core-shell electron transporting material

    KAUST Repository

    Mahmood, Khalid

    2015-01-01

    Until recently, only mesoporous TiO2 and ZnO were successfully demonstrated as electron transport layers (ETL) alongside the reports of ZrO2 and Al2O3 as scaffold materials in organometal halide perovskite solar cells, largely owing to ease of processing and to high power conversion efficiency. In this article, we explore tungsten trioxide (WO3)-based nanostructured and porous ETL materials directly grown hydrothermally with different morphologies such as nanoparticles, nanorods and nanosheet arrays. The nanostructure morphology strongly influences the photocurrent and efficiency in organometal halide perovskite solar cells. We find that the perovskite solar cells based on WO3 nanosheet arrays yield significantly enhanced photovoltaic performance as compared to nanoparticles and nanorod arrays due to good perovskite absorber infiltration in the porous scaffold and more rapid carrier transport. We further demonstrate that treating the WO3 nanostructures with an aqueous solution of TiCl4 reduces charge recombination at the perovskite/WO3 interface, resulting in the highest power conversion efficiency of 11.24% for devices based on WO3 nanosheet arrays. The successful demonstration of alternative ETL materials and nanostructures based on WO3 will open up new opportunities in the development of highly efficient perovskite solar cells. This journal is © The Royal Society of Chemistry 2015.

  20. Investigation of the La2O3-Nb2O5-WO3 ternary phase diagram: Isolation and crystal structure determination of the original La3NbWO10 material

    KAUST Repository

    Vu, T.D.

    2015-05-23

    In the course of the exploration of the La2O3-WO3-Nb2O5 ternary phase diagram, a new compound with the formula La3NbWO10 was discovered. Its structure was determined from a combination of powder X-ray and neutron diffraction data. It crystallizes in the tetragonal space group P42/nmc (no. 137) with the lattice parameters: a=10.0807(1) Å; c=12.5540(1) Å. The structure is built up from infinite ribbons of octahedra (W/Nb)O5 which are perpendicular to each other, lanthanum ions being distributed around these ribbons. The electrical properties of this compound were investigated on sintered pellets by means of complex impedance spectroscopy. © 2015 Elsevier Inc. All rights reserved.