Exploiting strain to enhance the Bi incorporation in GaAs-based III/V semiconductors using MOVPE

Science.gov (United States)

Nattermann, L.; Ludewig, P.; Sterzer, E.; Volz, K.

2017-07-01

Bi containing III/V semiconductors are frequently mentioned for their importance as part of the next generation of optoelectronic devices. Bi containing ternary and quaternary materials like Ga(AsBi), Ga(NAsBi) or Ga(PAsBi) are promising candidates to meet the requirements for new laser structures for telecommunications and solar cell applications. However, in previous studies it was determined that the incorporation of sufficient amounts of Bi still poses a challenge, especially when using MOVPE (metalorganic vapour phase epitaxy) as the growth technique. In order to figure out which mechanisms are responsible for the limitation of Bi incorporation, this work deals with the question of whether there is a relationship between strain, induced by the large Bi atoms, and the saturation level of Bi incorporation in Ga(AsBi). Ga(NAsBi) structures were grown by MOVPE at a low temperature, 400 °C, and compared to Ga(PAsBi) as well as Ga(AsBi) growth. By using the two group V atoms P and N, which have a smaller covalent radius than Bi, the effect of local strain compensation was investigated systematically. The comparison of Bi incorporation in the two quaternary materials systems proved the importance of local strain for the limitation of Bi incorporation, in addition to other effects, like Bi surface coverage and hydrocarbon groups at the growth surface. This, of course, also opens up ways to strain-state-engineer the Bi incorporation in semiconductor alloys.

The highly enhanced visible light photocatalytic degradation of gaseous o-dichlorobenzene through fabricating like-flowers BiPO{sub 4}/BiOBr p-n heterojunction composites

Energy Technology Data Exchange (ETDEWEB)

Zou, Xuejun [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian, 116600 (China); Dong, Yuying, E-mail: dongy@dlnu.edu.cn [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian, 116600 (China); Zhang, Xiaodong, E-mail: fatzhxd@126.com [Environment and Low-Carbon Research Center, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, 200093 (China); Cui, Yubo; Ou, Xiaoxia [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian, 116600 (China); Qi, Xiaohui [College of Life Science, Dalian Nationalities University, Dalian, 116600 (China)

2017-01-01

Highlights: • Like-flowers BiPO{sub 4}/BiOBr was fabricated by mixing in solvent method. • o-Dichlorobenzene removal efficiency was 53.6% using BiPO{sub 4}/BiOBr. • The p–n junction improved o-dichlorobenzene degradation activity. - Abstract: In this paper, in order to enhance photo-induced electron-hole pairs separation of BiOBr, flowers-like BiPO{sub 4}/BiOBr p-n heterojunction composites was fabricated by a mixing in solvent method. The as-prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), UV–vis absorption spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and N{sub 2} adsorption-desorption. Meanwhile, their photocatalytic properties were investigated by the degradation of gaseous o-dichlorobenzene under visible light irradiation. Due to its strong adsorption capacity and the formation of p-n heterojunction, compared with BiPO{sub 4} and BiOBr, the BiPO{sub 4}/BiOBr composites showed higher photocatalytic activity in the degradation of gaseous o-DCB under visible light. Among them, 2% BiPO{sub 4}/BiOBr showed the maximum value of the activity, whose degradation rate was about 2.6 times as great as the pure BiOBr. Furthermore, the OH· was confirmed the main active species during the photocatalytic process by the trapping experiments. The outstanding performance indicated that the photocatalysts could be applied to air purification for chlorinated volatile organic compound.

Camera Coverage Estimation Based on Multistage Grid Subdivision

Directory of Open Access Journals (Sweden)

Meizhen Wang

2017-04-01

Full Text Available Visual coverage is one of the most important quality indexes for depicting the usability of an individual camera or camera network. It is the basis for camera network deployment, placement, coverage-enhancement, planning, etc. Precision and efficiency are critical influences on applications, especially those involving several cameras. This paper proposes a new method to efficiently estimate superior camera coverage. First, the geographic area that is covered by the camera and its minimum bounding rectangle (MBR without considering obstacles is computed using the camera parameters. Second, the MBR is divided into grids using the initial grid size. The status of the four corners of each grid is estimated by a line of sight (LOS algorithm. If the camera, considering obstacles, covers a corner, the status is represented by 1, otherwise by 0. Consequently, the status of a grid can be represented by a code that is a combination of 0s or 1s. If the code is not homogeneous (not four 0s or four 1s, the grid will be divided into four sub-grids until the sub-grids are divided into a specific maximum level or their codes are homogeneous. Finally, after performing the process above, total camera coverage is estimated according to the size and status of all grids. Experimental results illustrate that the proposed method’s accuracy is determined by the method that divided the coverage area into the smallest grids at the maximum level, while its efficacy is closer to the method that divided the coverage area into the initial grids. It considers both efficiency and accuracy. The initial grid size and maximum level are two critical influences on the proposed method, which can be determined by weighing efficiency and accuracy.

The effect of Bi composition on the properties of InP{sub 1−x}Bi{sub x} grown by liquid phase epitaxy

Energy Technology Data Exchange (ETDEWEB)

Das, T. D., E-mail: tddas@hotmail.com [Department of Electronic Science, University of Calcutta, 92, A. P. C. Road, Kolkata 700009 (India)

2014-05-07

InP{sub 1−x}Bi{sub x} epilayers (x ≥ 1.2%) on InP (001) are grown reproducibly by liquid phase epitaxy with conventional solution baking in a H{sub 2} environment. The Bi composition and surface morphology of the grown layers are studied by secondary ion mass spectroscopy and atomic force microscopy, respectively. High-resolution x-ray diffraction is used to characterize the lattice parameters and the crystalline quality of the layers. 10 K photoluminescence measurements indicate three clearly resolved peaks in undoped InP layers with band-to-band transition at 1.42 eV which is redshifted with Bi incorporation in the layer with a maximum band gap reduction of 50 meV/% Bi. The effect is attributed to the interaction between the valence band edge and Bi-related defect states as is explained here by valence-band anticrossing model. Room temperature Hall measurements indicate that the mobility of the layer is not significantly affected for Bi concentration up to 1.2%.

Bi-induced sub graphs and stability number

Directory of Open Access Journals (Sweden)

Zverovich I.E.

2004-01-01

Full Text Available We define a 2-parametric hierarchy CLAP (m, n of bi-hereditary classes of graphs, and show that a maximum stable set can be found in polynomial time within each class CLAP (m, n. The classes can be recognized in polynomial time.

On Training Bi-directional Neural Network Language Model with Noise Contrastive Estimation

OpenAIRE

He, Tianxing; Zhang, Yu; Droppo, Jasha; Yu, Kai

2016-01-01

We propose to train bi-directional neural network language model(NNLM) with noise contrastive estimation(NCE). Experiments are conducted on a rescore task on the PTB data set. It is shown that NCE-trained bi-directional NNLM outperformed the one trained by conventional maximum likelihood training. But still(regretfully), it did not out-perform the baseline uni-directional NNLM.

Local Seebeck coefficient near the boundary in touching Cu/Bi-Te/Cu composites

International Nuclear Information System (INIS)

Yamashita, O.; Odahara, H.

2007-01-01

The thermo-emf ΔV and temperature difference ΔT across the boundary were measured as a function of r for the touching p- and n-type Cu/Bi-Te/Cu composites composed of a combination of t Bi-Te =2.0 mm and t Cu =0.3 mm, where ΔT is produced by imposing a constant voltage of 1.7 V on two Peltier modules connected in series and r is the distance from the boundary that corresponds to the interval s between two thermocouples. The resultant Seebeck coefficient α across the boundary was obtained from the relation α=ΔV/ΔT. As a result, the resultant α of the touching p- and n-type composites have surprisingly great local maximum values of 1330 and -1140 μV/K at r∼0.03 mm, respectively, and decreased rapidly with an increase of r to approach the Seebeck coefficients of the intrinsic Bi-Te compounds. The resultant maximum α of the touching p- and n-type Cu/Bi-Te/Cu composites are approximately 5.4 and 5.5 times higher in absolute value than those of the intrinsic Bi-Te compounds, respectively. It was thus clarified for the first time that the local Seebeck coefficient is enhanced most strongly in the Bi-Te region where there is an approximately 30-μm distance from the boundary, not at the boundary between Bi-Te compounds and copper. (orig.)

[Quantification of acetabular coverage in normal adult].

Science.gov (United States)

Lin, R M; Yang, C Y; Yu, C Y; Yang, C R; Chang, G L; Chou, Y L

1991-03-01

Quantification of acetabular coverage is important and can be expressed by superimposition of cartilage tracings on the maximum cross-sectional area of the femoral head. A practical Autolisp program on PC AutoCAD has been developed by us to quantify the acetabular coverage through numerical expression of the images of computed tomography. Thirty adults (60 hips) with normal center-edge angle and acetabular index in plain X ray were randomly selected for serial drops. These slices were prepared with a fixed coordination and in continuous sections of 5 mm in thickness. The contours of the cartilage of each section were digitized into a PC computer and processed by AutoCAD programs to quantify and characterize the acetabular coverage of normal and dysplastic adult hips. We found that a total coverage ratio of greater than 80%, an anterior coverage ratio of greater than 75% and a posterior coverage ratio of greater than 80% can be categorized in a normal group. Polar edge distance is a good indicator for the evaluation of preoperative and postoperative coverage conditions. For standardization and evaluation of acetabular coverage, the most suitable parameters are the total coverage ratio, anterior coverage ratio, posterior coverage ratio and polar edge distance. However, medial coverage and lateral coverage ratios are indispensable in cases of dysplastic hip because variations between them are so great that acetabuloplasty may be impossible. This program can also be used to classify precisely the type of dysplastic hip.

Thermoelectric properties of Bi2Te3-Bi2Se3 solid solutions prepared by attrition milling and hot pressing

International Nuclear Information System (INIS)

Lee, Go-Eun; Kim, Il-Ho; Choi, Soon-Mok; Lim, Young-Soo; Seo, Won-Seon; Park, Jae-Soung; Yang, Seung-Ho

2014-01-01

Bi 2 Te 3-y Se y (y = 0.15 - 0.6) solid solutions were prepared by attrition milling and hot pressing. The lattice constants decreased with increasing Se content, indicating that the Se atoms were successfully substituted into the Te sites. All specimens exhibited n-type conduction, and their electrical resistivities increased slightly with increasing temperature. With increasing Se content, the Seebeck coefficients increased while the thermal conductivity decreased due to the increase in phonon scattering. The maximum figure of merit obtained was 0.63 at 440 K for the undoped Bi 2 Te 2.4 Se 0.6 solid solution.

Magnetic properties and thermal stability of MnBi/NdFeB hybrid bonded magnets

International Nuclear Information System (INIS)

Cao, S.; Yue, M.; Yang, Y. X.; Zhang, D. T.; Liu, W. Q.; Zhang, J. X.; Guo, Z. H.; Li, W.

2011-01-01

Magnetic properties and thermal stability were investigated for the MnBi/NdFeB (MnBi = 0, 20, 40, 60, 80, and 100 wt.%) bonded hybrid magnets prepared by spark plasma sintering (SPS) technique. Effect of MnBi content on the magnetic properties of the hybrid magnets was studied. With increasing MnBi content, the coercivity of the MnBi/NdFeB hybrid magnets increases rapidly, while the remanence and maximum energy product drops simultaneously. Thermal stability measurement on MnBi magnet, NdFeB magnet, and the hybrid magnet with 20 wt.% MnBi indicates that both the NdFeB magnet and the MnBi/NdFeB hybrid magnet have a negative temperature coefficient of coercivity, while the MnBi magnet has a positive one. The (BH) max of the MnBi/NdFeB magnet (MnBi = 20 wt.%) is 5.71 MGOe at 423 K, which is much higher than 3.67 MGOe of the NdFeB magnet, indicating a remarkable improvement of thermal stability.

Effect of surface treatment of thermoelectric materials on the properties of thermoelements made from solid solutions of Bi/sub 2/Te/sub 3/-Bi/sub 2/Se/sub 3/ and Bi/sub 2/Te/sub 3/-Sb/sub 2/Te/sub 3/ systems

Energy Technology Data Exchange (ETDEWEB)

Alieva, T.D.; Abdinov, D.Sh.; Salaev, Eh.Yu.

1981-10-01

Effect of surface treatment technology of samples of solid solutions of Ei/sub 2/Te/sub 3/-Bi/sub 2/Se/sub 3/ and Bi/sub 2/Te/sub 3/-Sb/sub 2/Te/sub 3/ systems on their thermoelectric efficiency is studied. Branches of thermoelements have been produced with the help of electroerosion or mechanical cutting of monocrystal ingots of semiconducting solid Bi/sub 2/Te/sub 3/-base solutions. It is shown that in case of the treatment of side surfaces of branches of thermoelements produced of monocrystals of Bi/sub 2/Te/sub 3/ base solid solutions their thermoelectrical efficiency grows considerably. Maximum growth of efficiency (approximately 20%) is observed during mechanical grinding of branches surfaces with diamond paste with the following chemical or electrochemical etching.

Resistance–temperature relation and atom cluster estimation of In–Bi system melts

International Nuclear Information System (INIS)

Geng, Haoran; Wang Zhiming; Zhou Yongzhi; Li Cancan

2012-01-01

Highlights: ► A testing device was adopted to measure the electrical resistivity of In–Bi system melts. ► A basically linear relation exists between the resistivity and temperature of In x Bi 100−x melts in measured temperature range. ► Based on Novakovic's assumption, the content of InBi atomic cluster in In x Bi 100−x melt is estimated with ρ ≈ ρ InBi x InBi + ρ m (1 − x InBi ) equation. - Abstract: A testing device for the resistivity of high-temperature melt was adopted to measure the l resistivity of In–Bi system melts at different temperatures. It can be concluded from the analysis and calculation of the experimental results that the resistivity of In x Bi 100−x (x = 0–100) melt is in linear relationship with temperature within the experiment temperature range. The resistivity of the melt decreases with the increasing content of In. The fair consistency of resistivity of In–Bi system melt is found in the heating and cooling processes. On the basis of Novakovic's assumption, we approximately estimated the content of InBi atom clusters in In x Bi 100−x melts with the resistivity data by equation ρ ≈ ρ InBi x InBi + ρ m (1 − x InBi ). In the whole components interval, the content corresponds well with the mole fraction of InBi clusters calculated by Novakovic in the thermodynamic approach. The mole fraction of InBi type atom clusters in the melts reaches the maximum at the point of stoichiometric composition In 50 Bi 50 .

Bi surfactant mediated growth for fabrication of Si/Ge nanostructures and investigation of Si/Ge intermixing by STM

Energy Technology Data Exchange (ETDEWEB)

Paul, N.

2007-10-26

In the thesis work presented here, we show that Bi is more promising surfactant material than Sb. We demonstrate that by using Bi as a terminating layer on Ge/Si surface, it is possible to distinguish between Si and Ge in Scanning tunnelling microscope (STM). Any attempt to utilize surfactant mediated growth must be preceded by a thorough study of its effect on the the system being investigated. Thus, the third chapter of this thesis deals with an extensive study of the Bi surfactant mediated growth of Ge on Si(111) surface as a function of Ge coverage. The growth is investigated from the single bilayer Ge coverage till the Ge coverage of about 15 BL when the further Ge deposition leads to two-dimensional growth. In the fourth chapter, the unique property of Bi terminating layer on Ge/Si surface to result in an STM height contrast between Si and Ge is explained with possible explanations given for the reason of this apparent height contrast. The controlled fabrication of Ge/Si nanostructures such as nanowires and nanorings is demonstrated. A study on Ge-Si diffusion in the surface layers by a direct method such as STM was impossible previously because of the similar electronic structure of Ge and Si. Since with the Bi terminating surface layer, one is able to distinguish between Ge and Si, the study of intermixing between them is also possible using STM. This method to distinguish between Si and Ge allows one to study intermixing on the nanoscale and to identify the fundamental diffusion processes giving rise to the intermixing. In Chapter 5 we discuss how this could prove useful especially as one could get a local probe over a very narrow Ge-Si interface. A new model is proposed to estimate change in the Ge concentration in the surface layer with time. The values of the activation energies of Ge/Si exchange and Si/Ge exchange are estimated by fitting the experimental data with the model. The Ge/Si intermixing has been studied on a surface having 1 ML Bi ({radical

Bi-liquid foams

International Nuclear Information System (INIS)

Sonneville, Odile

1997-01-01

Concentrated emulsions have structures similar to foams; for this reason they are also called 'bi-liquid foams'. For oil in water emulsions, they are made of polyhedral oil cells separated by aqueous surfactant films. The limited stability of these Systems is a major nuisance in their applications. In this work, we tried to understand and to control the mechanisms through which bi-liquid foams can loose their stability. In a first stage, we characterized the states of surfactant films in bi-liquid foams submitted to different pressures. We determined their hydration, the surfactant density at interfaces as well as their thicknesses. The bi-liquid foams were made by concentrating hexadecane-in-water emulsions through centrifugation. The initial emulsions contained submicron oil droplets that were completely covered with surfactant. We measured the resistance of the films to dehydration, and we represented it by pressure-film thickness curves or pressure-film hydration curves. We also obtained evidence that the interfacial surfactant density increases when the film thickness is decreased (SDS case). The Newton Black Film state is the most dehydrated metastable state that can be reached. In this state, the films can be described as surfactant bilayers that only contain the hydration water of the surfactant polar heads. Two different processes are involved the destabilization of bi-liquid foams: Ostwald ripening (oil transfer from small cells to large cells) and coalescence (films rupture). The first mechanism can be controlled by choosing oils that are very insoluble in water, avoiding ethoxylated nonionic surfactants of low molecular weight, and making emulsions that are not too fine. The second mechanism is responsible for the catastrophic destabilization of bi-liquid foams made of droplets above one micron or with a low coverage in surfactant. In these cases, destabilization occurs in the early stages of concentration, when the films are still thick. It is caused

Achieving Crossed Strong Barrier Coverage in Wireless Sensor Network.

Science.gov (United States)

Han, Ruisong; Yang, Wei; Zhang, Li

2018-02-10

Barrier coverage has been widely used to detect intrusions in wireless sensor networks (WSNs). It can fulfill the monitoring task while extending the lifetime of the network. Though barrier coverage in WSNs has been intensively studied in recent years, previous research failed to consider the problem of intrusion in transversal directions. If an intruder knows the deployment configuration of sensor nodes, then there is a high probability that it may traverse the whole target region from particular directions, without being detected. In this paper, we introduce the concept of crossed barrier coverage that can overcome this defect. We prove that the problem of finding the maximum number of crossed barriers is NP-hard and integer linear programming (ILP) is used to formulate the optimization problem. The branch-and-bound algorithm is adopted to determine the maximum number of crossed barriers. In addition, we also propose a multi-round shortest path algorithm (MSPA) to solve the optimization problem, which works heuristically to guarantee efficiency while maintaining near-optimal solutions. Several conventional algorithms for finding the maximum number of disjoint strong barriers are also modified to solve the crossed barrier problem and for the purpose of comparison. Extensive simulation studies demonstrate the effectiveness of MSPA.

Local electric field screening in bi-layer graphene devices

Directory of Open Access Journals (Sweden)

Vishal ePanchal

2014-02-01

Full Text Available We present experimental studies of both local and macroscopic electrical effects in uniform single- (1LG and bi-layer graphene (2LG devices as well as in devices with non-uniform graphene coverage, under ambient conditions. DC transport measurements on sub-micron scale Hall bar devices were used to show a linear rise in carrier density with increasing amounts of 2LG coverage. Electrical scanning gate microscopy was used to locally top gate uniform and non-uniform devices in order to observe the effect of local electrical gating. We experimentally show a significant level of electric field screening by 2LG. We demonstrate that SGM technique is an extremely useful research tool for studies of local screening effects, which provides a complementary view on phenomena that are usually considered only within a macroscopic experimental scheme.

Microwave synthesis and electrochemical characterization of mesoporous carbon@Bi{sub 2}O{sub 3} composites

Energy Technology Data Exchange (ETDEWEB)

Xia, Nannan [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); Yuan, Dingsheng, E-mail: tydsh@jnu.edu.cn [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); Zhou, Tianxiang; Chen, Jingxing; Mo, Shanshan; Liu, Yingliang [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China)

2011-05-15

Graphical abstract: An efficient and quick microwave method has been employed to prepare worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites for the first time. The electrochemical measurement shows the worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites exhibits excellent capacitance performance and the maximum specific capacitance is up to 386 F g{sup -1}. Research highlights: {yields} An efficient and quick microwave method has been employed. {yields} A worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites have been successfully prepared. {yields} This composite exhibits excellent capacitance performance. {yields} This composite could be a potential electrode material for the supercapacitors. -- Abstract: An efficient and quick microwave method has been employed to prepare worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites for the first time. As-prepared products have been characterized by X-ray diffraction, N{sub 2} adsorption-desorption, scanning electron microscopy, transmission electron microscopy and inductive coupled plasma atomic emission spectroscopy. The electrochemical measurement shows the worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites exhibits excellent capacitance performance and the maximum specific capacitance reaches 386 F g{sup -1}, three times more than the pure worm-like mesoporous carbon.

A Phase I Dose-Escalation Study of Antibody BI-505 in Relapsed/Refractory Multiple Myeloma

DEFF Research Database (Denmark)

Hansson, Markus; Gimsing, Peter; Badros, Ashraf

2015-01-01

PURPOSE: This multicenter, first-in-human study evaluated safety, tolerability, pharmacokinetics, and pharmacodynamics of BI-505, a human anti-ICAM-1 monoclonal antibody, in advanced relapsed/refractory multiple myeloma patients. EXPERIMENTAL DESIGN: BI-505 was given intravenously, every 2 weeks...... generally mild to moderate, and those attributed to study medication were mostly limited to the first dose and manageable with premedication and slower infusion. No maximum tolerated dose was identified. BI-505's half-life increased with dose while clearance decreased, suggesting target-mediated clearance...

On the effect of coverage-dependent adsorbate-adsorbate interactions for CO methanation on transition metal surfaces

DEFF Research Database (Denmark)

Lausche, Adam C.; Medford, Andrew J.; Khan, Tuhin Suvra

2013-01-01

with a high coverage of CO. At these high coverages, reaction intermediates experience interaction effects that typically reduce their adsorption energies. Herein, the effect of these interactions on the activities of transition metals for CO methanation is investigated. For transition metals that have low...... coverages of reactants, the effect is minimal. But for materials with high coverages under reaction conditions, rates can change by several orders of magnitude. Nevertheless, the position of the maximum of the activity volcano does not shift significantly, and the rates at the maximum are only slightly......Heterogeneously catalyzed reactions involving the dissociation of strongly bonded molecules typically need quite reactive catalysts with high coverages of intermediate molecules. Methanation of carbon monoxide is one example, where CO dissociation has been reported to take place on step sites...

Bi:Ge substitution - its effect on the structural and electrical properties of the Bi2212 superconductor

International Nuclear Information System (INIS)

Saligan, P.P.

1997-03-01

The critical temperature determined from dc resistance and ac magnetic susceptibility measurements, and the coherence length obtained from the of fluctuation conductivity of polycrystalline Bi 2-x Ge x Sr 2 CaCu 2 O 8 +δ were studied. The effect of sample quality was also studied by making two kinds of pellet samples: (1) by conventional sintering process and (2) by conventional sintering process followed annealing at high temperature. The rough phase diagram of Bi 2-x Ge x Sr 2 CaCu 2 O 8 +δ was constructed and it was found that from x=0 to x=0.3 a predominantly Bi2212 phase can be obtained. The critical temperature of the unsubstituted Bi 2 Sr 2 CaCu 2 O 8 +δ is sensitive to the cold press and anneal method. The resistive transition T c based on the maximum dR(T)dT of the as-sintered Bi 2 Sr 2 CaCu 2 O 8 +δ is about 74 K. The resistive T c of the cold-pressed-annealed samples either (1) remain near 74 K or (2) increase to approximately 85 K or (3) show two values at about 74 K and 85 K. A structural relaxation is observed in the Bi 2-x Ge x Sr 2 CaCu 2 O 8 +δ the c-axis decreases with increasing x and the a-axis increases at x=0.1 then settles back to its unsubstituted value at higher x. The as-sintered samples show an increasing resistive T c with x, 74 K for x=0 and 79 K for x>0. The resistive T c 's of the cold-pressed-annealed samples are almost independent of x, 85 K for x=0 and 87 K for x>0. The increase in the magnetic critical temperature induced by the cold press and anneal method is considerably larger compared to the increase in the resistive critical temperature, independent of the Bi:Ge substitution. An analysis of fluctuation conductivity just above T c using the Aslamasov-Larkin model for two-dimensional superconductors and the Lawrence-Doniach model for layered superconductors was done. The Aslamasov-Larkin model gives the thickness of the two dimensional superconductor to be ∼34 A also independent of the Bi:Ge substitution. The Lawrence

On the synthesis and microstructure analysis of high performance MnBi

Directory of Open Access Journals (Sweden)

Yu-Chun Chen

2016-12-01

Full Text Available Highly anisotropic MnBi powder with over 90 wt% low-temperature phase can be prepared using conventional arc-melting and 2 hour-low energy ball milling (BM followed by magnetic separation. After proper alignment, the purified Mn55Bi45(Mn45Bi55 powder show remarkable magnetic properties: mass remanence of 71(65 Am2/kg and coercivity of 1.23(1.18 T at 300 K. The nominal maximum energy product of 120 kJ/m3 is achieved in the purified 2h-BM Mn55Bi45 powder, close to theoretical value of 140.8 kJ/m3. The Mn55Bi45(Mn45Bi55 bulk magnets show the highest volume remanence of 0.68(0.57 T at 300 K, while they were consolidated at 573(523 K by a pressure of 200 MPa for 5 minutes using hot-compaction method. In addition to the observed grain size, the coercivity of the hot-compacted samples at 300 K was found to be strongly related to the amount of metallic Mn and Bi residue at the grain-boundary. Our study proves that the magnetic properties of the Mn45Bi55 bulk magnets are stable up to 500 K, and the nominal (BHmax values are still above 40 kJ/m3 at 500 K showing the potential ability for high-temperature applications.

Bi-Force

DEFF Research Database (Denmark)

Sun, Peng; Speicher, Nora K; Röttger, Richard

2014-01-01

of pairwise similarities. We first evaluated the power of Bi-Force to solve dedicated bicluster editing problems by comparing Bi-Force with two existing algorithms in the BiCluE software package. We then followed a biclustering evaluation protocol in a recent review paper from Eren et al. (2013) (A...... comparative analysis of biclustering algorithms for gene expressiondata. Brief. Bioinform., 14:279-292.) and compared Bi-Force against eight existing tools: FABIA, QUBIC, Cheng and Church, Plaid, BiMax, Spectral, xMOTIFs and ISA. To this end, a suite of synthetic datasets as well as nine large gene expression...

Effects of aging time on the mechanical properties of Sn–9Zn–1.5Ag–xBi lead-free solder alloys

International Nuclear Information System (INIS)

Liu, Chih-Yao; Hon, Min-Hsiung; Wang, Moo-Chin; Chen, Ying-Ru; Chang, Kuo-Ming; Li, Wang-Long

2014-01-01

Highlights: • The microstructure of these solder alloys are composed of Sn-rich phase and Ag 3 Sn. • The grain size of Sn–9Zn–1.5Ag–xBi solder alloys increases with rose aging time. • The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloys. • TEM observed that Bi appears as oblong shape fine particles. -- Abstract: The effects of aging time on the mechanical properties of the Sn–9Zn–1.5Ag–xBi lead-free solder alloys are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometry (EDS) and a universal testing machine. The experimental results show that the microstructure of Sn–9Zn–1.5Ag–xBi solder alloys is composed of Sn-rich phase and AgZn 3 . No other intermetallic compounds (IMCs) with Bi content was observed in the solder matrix for Sn–9Zn–1.5Ag solder alloys with various Bi contents before and after aging at 150 °C for different durations. The lattice parameter increases significantly with increasing aging time or Bi addition. The size of Sn-rich grain increased gradually with aging time increased, but decreases with Bi content increases. The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloy before aging

Effects of aging time on the mechanical properties of Sn–9Zn–1.5Ag–xBi lead-free solder alloys

Energy Technology Data Exchange (ETDEWEB)

Liu, Chih-Yao [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Hon, Min-Hsiung [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, Kaohsiung 80728, Taiwan (China); Chen, Ying-Ru; Chang, Kuo-Ming; Li, Wang-Long [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan (China)

2014-01-05

Highlights: • The microstructure of these solder alloys are composed of Sn-rich phase and Ag{sub 3}Sn. • The grain size of Sn–9Zn–1.5Ag–xBi solder alloys increases with rose aging time. • The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloys. • TEM observed that Bi appears as oblong shape fine particles. -- Abstract: The effects of aging time on the mechanical properties of the Sn–9Zn–1.5Ag–xBi lead-free solder alloys are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometry (EDS) and a universal testing machine. The experimental results show that the microstructure of Sn–9Zn–1.5Ag–xBi solder alloys is composed of Sn-rich phase and AgZn{sub 3}. No other intermetallic compounds (IMCs) with Bi content was observed in the solder matrix for Sn–9Zn–1.5Ag solder alloys with various Bi contents before and after aging at 150 °C for different durations. The lattice parameter increases significantly with increasing aging time or Bi addition. The size of Sn-rich grain increased gradually with aging time increased, but decreases with Bi content increases. The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloy before aging.

Pulsed Q-switched ruby laser annealing of Bi implanted Si crystals investigated by channeling

International Nuclear Information System (INIS)

Deutch, B.I.; Shih-Chang, T.; Shang-Hwai, L.; Zu-Yao, Z.; Jia-Zeng, H.; Ren-Zhi, D.; Te-Chang, C.; De-Xin, C.

1979-01-01

Channeling was used to investigate pulsed, Q switched ruby-laser annealed and thermally annealed Si single crystals implanted with 40-keV Bi ions to a dose of 10 15 atoms/cm 2 . After thermal annealing, residual damage decreased with increasing annealing temperature to a minimum value of 30% at 900 0 C. The Bi atoms in substitutional sites reached a maximum value (50%) after annealing at 750 0 C but decreased with increasing annealing temperature. Out diffusion of Bi atoms occurred at temperatures higher than 625 0 C. For comparison, the residual damage disappeared almost completely after pulsed-laser annealing (30 ns pulse width, Energy, E = 3J/cm 2 ). The concentration of Bi in Si exceeded its solid solubility by an order of magnitude; 95% of Bi atoms were annealed to substitutional sites. Laser pulses of different energies were used to investigate the efficiency of annealing. (author)

Magnetoelectric coupling effect in transition metal modified polycrystalline BiFeO3 thin films

International Nuclear Information System (INIS)

Sreenivas Puli, Venkata; Kumar Pradhan, Dhiren; Gollapudi, Sreenivasulu; Coondoo, Indrani; Panwar, Neeraj; Adireddy, Shiva; Chrisey, Douglas B.; Katiyar, Ram S.

2014-01-01

Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO 3 (BFO) thin films have been deposited on Pt/TiO 2 /SiO 2 /Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical “butterfly-shaped” loop were observed in BSFCO films with an effective piezoelectric constant (d 33 ) ∼94 pm/V at 0.6 MV/cm. High dielectric constant ∼900 and low dielectric loss ∼0.25 were observed at room temperature. M–H loops have shown relatively high saturation magnetization ∼35 emu/cm 3 at a maximum field of H ∼20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films. - Highlights: • Transition metal modified polycrystalline BiFeO 3 thin films prepared using PLD. • High ME-coupling response was observed in co-substituted BiFeO 3 thin films. • High magnetization ∼35 emu/cm 3 at a maximum field of H ∼20 kOe. • Low leakage current might be due to co-substitution in BiFeO 3 thin films. • A notable piezoelectric constant d 33 ∼94 pm/V was found in BiFeO 3 thin films

LA phonons scattering of surface electrons in Bi2Se3

International Nuclear Information System (INIS)

Huang, Lang-Tao; Zhu, Bang-Fen

2013-01-01

Within the Boltzmann equation formalism we evaluate the transport relaxation time of Dirac surface states (SSs) in the typical topological insulator(TI) Bi 2 Se 3 due to the phonon scattering. We find that although the back-scattering of the SSs in TIs is strictly forbidden, the in-plane scattering between SSs in 3-dimensional TIs is allowed, maximum around the right-angle scattering. Thus the topological property of the SSs only reduces the scattering rate to its one half approximately. Besides, the larger LA deformation potential and lower sound velocity of Bi 2 Se 3 enhance the scattering rate significantly. Compared with the Dirac electrons in graphene, we find the scattering rate of SSs in Bi 2 Se 3 are two orders of magnitudes larger, which agree with the recent transport experiments

Bi-induced band gap reduction in epitaxial InSbBi alloys

Energy Technology Data Exchange (ETDEWEB)

Rajpalke, M. K.; Linhart, W. M.; Birkett, M.; Alaria, J.; Veal, T. D., E-mail: T.Veal@liverpool.ac.uk [Stephenson Institute for Renewable Energy and Department of Physics, School of Physical Sciences, University of Liverpool, Liverpool L69 7ZF (United Kingdom); Yu, K. M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Bomphrey, J. J.; Jones, T. S.; Ashwin, M. J., E-mail: M.J.Ashwin@warwick.ac.uk [Department of Chemistry, University of Warwick, Coventry CV4 7AL (United Kingdom); Sallis, S.; Piper, L. F. J. [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

2014-11-24

The properties of molecular beam epitaxy-grown InSb{sub 1−x}Bi{sub x} alloys are investigated. Rutherford backscattering spectrometry shows that the Bi content increases from 0.6% for growth at 350 °C to 2.4% at 200 °C. X-ray diffraction indicates Bi-induced lattice dilation and suggests a zinc-blende InBi lattice parameter of 6.626 Å. Scanning electron microscopy reveals surface InSbBi nanostructures on the InSbBi films for the lowest growth temperatures, Bi droplets at intermediate temperatures, and smooth surfaces for the highest temperature. The room temperature optical absorption edge was found to change from 172 meV (7.2 μm) for InSb to ∼88 meV (14.1 μm) for InSb{sub 0.976}Bi{sub 0.024}, a reduction of ∼35 meV/%Bi.

Enhancement of thermoelectric properties of Mg2Si compounds with Bi doping through carrier concentration tuning

Science.gov (United States)

Lee, Ji Eun; Cho, Sang-Hum; Oh, Min-Wook; Ryu, Byungi; Joo, Sung-Jae; Kim, Bong-Seo; Min, Bok-Ki; Lee, Hee-Woong; Park, Su-Dong

2014-07-01

The Bi-doped Mg2Si powder was fabricated with solid state reaction method and consolidated with hot pressing method and then its thermoelectric properties were investigated. The n-type transport properties were measured in all samples and temperature dependence of the electrical properties shows a behavior of degenerate semiconductors for Bi-doped samples. The electrical resistivity and the Seebeck coefficient were greatly reduced with Bi, which was mainly due to the increment of the carrier concentration. The samples have maximum carrier concentration of 8.2 × 1018 cm-3. The largest ZT value of 0.61 was achieve at 873 K for Mg2.04SiBi0.02. The Bi-doping was found to be an effective n-type dopant to adjust carrier concentration. [Figure not available: see fulltext.

Anomalous magneto-structural behavior of MnBi explained: A path towards an improved permanent magnet

Energy Technology Data Exchange (ETDEWEB)

Zarkevich, N. A., E-mail: zarkev@ameslab.gov; Wang, L.-L. [The Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Johnson, D. D. [The Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2014-03-01

Low-temperature MnBi (hexagonal NiAs phase) exhibits anomalies in the lattice constants (a, c) and bulk elastic modulus (B) below 100 K, spin reorientation and magnetic susceptibility maximum near 90 K, and, importantly for high-temperature magnetic applications, an increasing coercivity (unique to MnBi) above 180  K. We calculate the total energy and magneto-anisotropy energy (MAE) versus (a, c) using DFT+U methods. We reproduce and explain all the above anomalies. We predict that coercivity and MAE increase due to increasing a, suggesting means to improve MnBi permanent magnets.

Anomalous magneto-structural behavior of MnBi explained: A path towards an improved permanent magnet

Energy Technology Data Exchange (ETDEWEB)

Zarkevich, NA; Wang, LL; Johnson, DD

2014-03-01

Low-temperature MnBi (hexagonal NiAs phase) exhibits anomalies in the lattice constants (a, c) and bulk elastic modulus (B) below 100 K, spin reorientation and magnetic susceptibility maximum near 90 K, and, importantly for high-temperature magnetic applications, an increasing coercivity (unique to MnBi) above 180 K. We calculate the total energy and magneto-anisotropy energy (MAE) versus (a, c) using DFT+U methods. We reproduce and explain all the above anomalies. We predict that coercivity and MAE increase due to increasing a, suggesting means to improve MnBi permanent magnets. (C) 2014 Author(s).

Adsorption-controlled growth of BiMnO3 films by molecular-beam epitaxy

International Nuclear Information System (INIS)

Lee, J. H.; Ke, X.; Misra, R.; Schiffer, P.; Ihlefeld, J. F.; Mei, Z. G.; Liu, Z. K.; Xu, X. S.; Musfeldt, J. L.; Heeg, T.; Schlom, D. G.; Roeckerath, M.; Schubert, J.

2010-01-01

We have developed the means to grow BiMnO 3 thin films with unparalleled structural perfection by reactive molecular-beam epitaxy and determined its band gap. Film growth occurs in an adsorption-controlled growth regime. Within this growth window bounded by oxygen pressure and substrate temperature at a fixed bismuth overpressure, single-phase films of the metastable perovskite BiMnO 3 may be grown by epitaxial stabilization. X-ray diffraction reveals phase-pure and epitaxial films with ω rocking curve full width at half maximum values as narrow as 11 arc sec (0.003 deg. ). Optical absorption measurements reveal that BiMnO 3 has a direct band gap of 1.1±0.1 eV.

Dispersion interactions between neighboring Bi atoms in (BiH3 )2 and Te(BiR2 )2.

Science.gov (United States)

Haack, Rebekka; Schulz, Stephan; Jansen, Georg

2018-03-13

Triggered by the observation of a short Bi⋯Bi distance and a BiTeBi bond angle of only 86.6° in the crystal structure of bis(diethylbismuthanyl)tellurane quantum chemical computations on interactions between neighboring Bi atoms in Te(BiR 2 ) 2 molecules (R = H, Me, Et) and in (BiH 3 ) 2 were undertaken. Bi⋯Bi distances atoms were found to significantly shorten upon inclusion of the d shells of the heavy metal atoms into the electron correlation treatment, and it was confirmed that interaction energies from spin component-scaled second-order Møller-Plesset theory (SCS-MP2) agree well with coupled-cluster singles and doubles theory including perturbative triples (CCSD(T)). Density functional theory-based symmetry-adapted perturbation theory (DFT-SAPT) was used to study the anisotropy of the interplay of dispersion attraction and steric repulsion between the Bi atoms. Finally, geometries and relative stabilities of syn-syn and syn-anti conformers of Te(BiR 2 ) 2 (R = H, Me, Et) and interconversion barriers between them were computed. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Liquid structure and temperature invariance of sound velocity in supercooled Bi melt

International Nuclear Information System (INIS)

Emuna, M.; Mayo, M.; Makov, G.; Greenberg, Y.; Caspi, E. N.; Yahel, E.; Beuneu, B.

2014-01-01

Structural rearrangement of liquid Bi in the vicinity of the melting point has been proposed due to the unique temperature invariant sound velocity observed above the melting temperature, the low symmetry of Bi in the solid phase and the necessity of overheating to achieve supercooling. The existence of this structural rearrangement is examined by measurements on supercooled Bi. The sound velocity of liquid Bi was measured into the supercooled region to high accuracy and it was found to be invariant over a temperature range of ∼60°, from 35° above the melting point to ∼25° into the supercooled region. The structural origin of this phenomenon was explored by neutron diffraction structural measurements in the supercooled temperature range. These measurements indicate a continuous modification of the short range order in the melt. The structure of the liquid is analyzed within a quasi-crystalline model and is found to evolve continuously, similar to other known liquid pnictide systems. The results are discussed in the context of two competing hypotheses proposed to explain properties of liquid Bi near the melting: (i) liquid bismuth undergoes a structural rearrangement slightly above melting and (ii) liquid Bi exhibits a broad maximum in the sound velocity located incidentally at the melting temperature

The role of the isolated 6s states in BiVO{sub 4} on the electronic and atomic structures

Energy Technology Data Exchange (ETDEWEB)

Ma, Jie; Wang, Lin-Wang [Joint Center for Artificial Photosynthesis and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2014-10-27

BiVO{sub 4} is one of the most promising photoanodes for water-splitting applications. Similar to many d{sup 10} materials, where the full-shell d electrons are not directly involved in the bonding, the Bi 6s electrons form isolated low-energy bands in BiVO{sub 4}. By systematically altering the energy of the Bi 6s states, we find direct evidences that the isolated s states, through the s-p coupling, affect the BiVO{sub 4} properties, including valence band maximum position, charge density, and atomic structural distortion. We find that many good properties of BiVO{sub 4} for water splitting are related to the s-p coupling due to the existence of Bi 6s states. Based on this understanding, we propose that alloying Bi with Sb can enhance these properties, and hence improve the water-splitting efficiency.

Facile synthesis of Bi/BiOCl composite with selective photocatalytic properties

International Nuclear Information System (INIS)

Chen, Dongling; Zhang, Min; Lu, Qiuju; Chen, Junfang; Liu, Bitao; Wang, Zhaofeng

2015-01-01

This paper presents a novel and facile method to fabricate Bi/BiOCl composites with dominant (001) facets in situ via a microwave reduction route. Different characterization techniques, including X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission scanning electron microscopy (TEM), UV–vis diffuse reflectance spectrometry (DRS), X-ray photoelectron spectroscopy (XPS), electron spin resonance spectroscopy (ESR), cathodoluminescence spectrum (CL), and lifetime, have been employed to investigate the structure, optical and electrical properties of the Bi/BiOCl composites. The experimental results show that the introduction of Bi particles can efficiently enhance the photocatalytic performance of BiOCl for the degradation of several dyes under ultraviolet (UV) light irradiation, especially for negative charged methyl orange (MO). Unlike the UV photocatalytic performance, such Bi/BiOCl composite shows higher degradation efficiency towards rhodamine B (RhB) than MO and methylene blue (MB) under visible light irradiation. This special photocatalytic performance can be ascribed to the synergistic effect between oxygen vacancies and Bi particles. This work provides new insights about the photodegradation mechanisms of MO, MB and RhB under UV and visible light irradiation, which would be helpful to guide the selection of an appropriate catalyst for other pollutants. - Highlights: • Bi/BiOCl composites were synthesized via a microwave reduction. • Tunable selectivity photocatalytic activity can be achieved. • Photodegradation mechanism under UV and visible light were proposed

Synthesis, crystal structure and optical properties of BiMgVO 5

Science.gov (United States)

Benmokhtar, S.; El Jazouli, A.; Chaminade, J. P.; Gravereau, P.; Guillen, F.; de Waal, D.

2004-11-01

The new vanadate BiMgVO 5 has been prepared and its structure has been determined by single crystal X-ray diffraction: space group P21/n, a=7.542(6) Å, b=11.615(5) Å, c=5.305(3) Å, β=107.38(5)°, wR2=0.0447, R=0.0255. The structure consists of [Mg 2O 10] and [Bi 2O 10] dimers sharing their corners with [VO 4] tetrahedra. The ranges of bond lengths are 2.129-2.814 Å for Bi-O; 2.035-2.167 Å for Mg-O and 1.684-1.745 Å for V-O. V-O bond lengths determined from Raman band wavenumbers are between 1.679 and 1.747 Å. An emission band overlapping the entire visible region with a maximum around 650 nm is observed.

Enhancement of superconductivity near the pressure-induced semiconductor-metal transition in the BiS₂-based superconductors LnO₀.₅F₀.₅BiS₂ (Ln = La, Ce, Pr, Nd).

Science.gov (United States)

Wolowiec, C T; White, B D; Jeon, I; Yazici, D; Huang, K; Maple, M B

2013-10-23

Measurements of electrical resistivity were performed between 3 and 300 K at various pressures up to 2.8 GPa on the BiS2-based superconductors LnO0.5F0.5BiS2 (Ln=Pr, Nd). At lower pressures, PrO0.5F0.5BiS2 and NdO0.5F0.5BiS2 exhibit superconductivity with critical temperatures Tc of 3.5 and 3.9 K, respectively. As pressure is increased, both compounds undergo a transition at a pressure Pt from a low Tc superconducting phase to a high Tc superconducting phase in which Tc reaches maximum values of 7.6 and 6.4 K for PrO0.5F0.5BiS2 and NdO0.5F0.5BiS2, respectively. The pressure-induced transition is characterized by a rapid increase in Tc within a small range in pressure of ∼0.3 GPa for both compounds. In the normal state of PrO0.5F0.5BiS2, the transition pressure Pt correlates with the pressure where the suppression of semiconducting behaviour saturates. In the normal state of NdO0.5F0.5BiS2, Pt is coincident with a semiconductor-metal transition. This behaviour is similar to the results recently reported for the LnO0.5F0.5BiS2 (Ln=La, Ce) compounds. We observe that Pt and the size of the jump in Tc between the two superconducting phases both scale with the lanthanide element in LnO0.5F0.5BiS2 (Ln=La, Ce, Pr, Nd).

Bismuth-boron multiple bonding in BiB_2O"- and Bi_2B"-

International Nuclear Information System (INIS)

Jian, Tian; Cheung, Ling Fung; Chen, Teng-Teng; Wang, Lai-Sheng

2017-01-01

Despite its electron deficiency, boron is versatile in forming multiple bonds. Transition-metal-boron double bonding is known, but boron-metal triple bonds have been elusive. Two bismuth boron cluster anions, BiB_2O"- and Bi_2B"-, containing triple and double B-Bi bonds are presented. The BiB_2O"- and Bi_2B"- clusters are produced by laser vaporization of a mixed B/Bi target and characterized by photoelectron spectroscopy and ab initio calculations. Well-resolved photoelectron spectra are obtained and interpreted with the help of ab initio calculations, which show that both species are linear. Chemical bonding analyses reveal that Bi forms triple and double bonds with boron in BiB_2O"- ([Bi≡B-B≡O]"-) and Bi_2B"- ([Bi=B=Bi]"-), respectively. The Bi-B double and triple bond strengths are calculated to be 3.21 and 4.70 eV, respectively. This is the first experimental observation of Bi-B double and triple bonds, opening the door to design main-group metal-boron complexes with multiple bonding. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

The modulation and reconstruction of a BiO layer of cuprate Bi2212

International Nuclear Information System (INIS)

Fan Wei; Zeng, Z

2011-01-01

Studies based on ab initio density functional theory show that the modulated structures of BiO surfaces of cuprate Bi2212 superconductors are spontaneously formed and closely related to the reconstructions of BiO surfaces. The reconstructions of BiO layers occur both on the surface and in the bulk, accompanied with the formations of BiO-zigzag chains and Bi 2 O 2 quadrilaterals. The structural modulations of the BiO surface are along the b axis, perpendicular to the BiO-zigzag chains along the a axis. Our calculations provide a unified understanding of the formation of modulating structures in Bi2212. Another interesting result is that electronic structures of BiO surfaces are significantly influenced by the CuO 2 layer beneath because of the structural modulations and reconstructions.

Magnetoelectric coupling effect in transition metal modified polycrystalline BiFeO{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Sreenivas Puli, Venkata, E-mail: pvsri123@gmail.com [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118 (United States); Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States); Kumar Pradhan, Dhiren [Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States); Gollapudi, Sreenivasulu [Department of Physics, Oakland University, Rochester, MI 48309-4401 (United States); Coondoo, Indrani [Department of Materials and Ceramic and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Panwar, Neeraj [Department of Physics, Central University of Rajasthan, Bandar Sindri, Kishangarh 305801, Rajasthan (India); Adireddy, Shiva; Chrisey, Douglas B. [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118 (United States); Katiyar, Ram S. [Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States)

2014-11-15

Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO{sub 3} (BFO) thin films have been deposited on Pt/TiO{sub 2}/SiO{sub 2}/Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical “butterfly-shaped” loop were observed in BSFCO films with an effective piezoelectric constant (d{sub 33}) ∼94 pm/V at 0.6 MV/cm. High dielectric constant ∼900 and low dielectric loss ∼0.25 were observed at room temperature. M–H loops have shown relatively high saturation magnetization ∼35 emu/cm{sup 3} at a maximum field of H ∼20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films. - Highlights: • Transition metal modified polycrystalline BiFeO{sub 3} thin films prepared using PLD. • High ME-coupling response was observed in co-substituted BiFeO{sub 3} thin films. • High magnetization ∼35 emu/cm{sup 3} at a maximum field of H ∼20 kOe. • Low leakage current might be due to co-substitution in BiFeO{sub 3} thin films. • A notable piezoelectric constant d{sub 33} ∼94 pm/V was found in BiFeO{sub 3} thin films.

Novel Bi/BiOBr/AgBr composite microspheres: Ion exchange synthesis and photocatalytic performance

Science.gov (United States)

Lyu, Jianchang; Li, Zhenlu; Ge, Ming

2018-06-01

Novel Bi/BiOBr/AgBr composite microspheres were prepared by a rational in situ ion exchange reaction between Bi/BiOBr microspheres and AgNO3. The characteristic of the as-obtained ternary microspheres was tested by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL). Under visible light irradiation, Bi/BiOBr/AgBr microspheres exhibited an excellent photocatalytic efficiency for rhodamine B (RhB) degradation, which was about 1.4 and 4.9 times as high as that of Bi/BiOBr and BiOBr/AgBr, demonstrating that the highest separation efficiency of charge carriers in the heterostructured Bi/BiOBr/AgBr. The photocatalytic activity of Bi/BiOBr/AgBr microspheres just exhibited a slight decrease after three consecutive cycles. The photocatalytic mechanism investigation confirmed that the superoxide radicals (O2•-) were the dominant reactive oxygen species for RhB degradation in Bi/BiOBr/AgBr suspension.

Photocatalytic activity of Bi_2WO_6/Bi_2S_3 heterojunctions: the facilitation of exposed facets of Bi_2WO_6 substrate

International Nuclear Information System (INIS)

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

2017-01-01

Highlights: • Bi_2S_3/Bi_2WO_6 hybrids with exposed (020) Bi_2WO_6 facets have been synthesized. • X-ray photoelectron spectroscopy reveals that a small amount of Bi_2S_3 was formed. • The enhanced photoactivity of hybrids is due to heterojunction and (020) facets. • A possible photocatalytic degradation mechanism is proposed. - Abstract: Bi_2S_3/Bi_2WO_6 hybrid architectures with exposed (020) Bi_2WO_6 facets have been synthesized via a controlled anion exchange approach. X-ray photoelectron spectroscopy (XPS) reveals that a small amount of Bi_2S_3 was formed on the surface of Bi_2WO_6 during the anion exchange process, thus leading to the transformation from the Bi_2WO_6 to Bi_2S_3/Bi_2WO_6. A rhodamine B (RhB) aqueous solution was chosen as model organic pollutants to evaluate the photocatalytic activities of the Bi_2S_3/Bi_2WO_6 catalysts. Under visible light irradiation, the Bi_2S_3/Bi_2WO_6-TAA displayed the excellent visible light photoactivities compared with pure Bi_2S_3, Bi_2WO_6 and other composite photocatalysts. The efficient photocatalytic activity of the Bi_2S_3/Bi_2WO_6-TAA composite microspheres was ascribed to the constructed heterojunctions and the inner electric field caused by the exposed (020) Bi_2WO_6 facets. Active species trapping experiments revealed that h"+ and O_2·"− are the main active species in the photocatalytic process. Furthermore, the as-obtained photocatalysts showed good photocatalytic activity after four recycles. The results presented in this study provide a new concept for the rational design and development of highly efficient photocatalysts.

Sequential electro-deposition of Bi{sub 2}S{sub 3}/CdS films as co-sensitizer photoanodes for liquid junction solar cell

Energy Technology Data Exchange (ETDEWEB)

Jana, Atanu; Hazra, Prasenjit; Hazra, Mukul; Datta, Jayati, E-mail: jayati_datta@rediffmail.com

2016-11-01

In this investigation multilayered conjugate films are formulated with Bi{sub 2}S{sub 3} and CdS nanoparticles (NPs) on FTO glass substrate. Thin layer Bi{sub 2}S{sub 3} was deposited and subsequently covered with various levels of CdS coating. Optical properties and XRD analysis of the films show existence of both the compound phases. The morphology of the films studied through electron microscopy reveals coverage of spherical CdS NPs on the network of Bi{sub 2}S{sub 3} NPs. The electrochemical impedance records and performances output characteristics of the n-type films show that the most efficient co-sensitizer matrix is produced with deep coating of CdS on thin layer of Bi{sub 2}S{sub 3}. - Highlights: • Multilayered Bi{sub 2}S{sub 3}/CdS conjugate films are formulated on FTO glass substrate. • Photo-degradation of Bi{sub 2}S{sub 3} is restricted by the coating of CdS layer. • High level of Cd coating on thin layer of Bi{sub 2}S{sub 3} have shown appreciable photocurrent output. • Photo-conversion efficiency of 0.93% is observed for the best conjugate film.

Heterojunction BiOI/Bi2MoO6 nanocomposite with much enhanced photocatalytic activity

International Nuclear Information System (INIS)

Li, Wen Ting; Zheng, Yi Fan; Yin, Hao Yong; Song, Xu Chun

2015-01-01

BiOI/Bi 2 MoO 6 heterostructures with different amounts of BiOI were successfully prepared via a facile deposition method. The obtained BiOI/Bi 2 MoO 6 photocatalysts exhibited much higher visible light (λ > 420 nm) induced photocatalytic activity compared with single Bi 2 MoO 6 and BiOI photocatalysts. 20 % BiOI/Bi 2 MoO 6 nanocomposite exhibited the highest photocatalytic activity with almost all RhB decomposed within 70 min. However, excess BiOI covering on the surface of Bi 2 MoO 6 can inversely reduce the photocatalytic activity. The enhanced photocatalytic activities could be resulted from the function of the novel p–n heterojunction interface between Bi 2 MoO 6 and BiOI, which could separate photoinduced carriers efficiently. Possible mechanisms on the basis of the relative band positions were also discussed

Multiferroic BiFeO3-BiMnO3 Nanocheckerboard From First Principles

OpenAIRE

Palova, L.; Chandra, P.; Rabe, K. M.

2010-01-01

We present a first principles study of an unusual heterostructure, an atomic-scale checkerboard of BiFeO3-BiMnO3, and compare its properties to the two bulk constituent materials, BiFeO3 and BiMnO3. The "nanocheckerboard" is found to have a multiferroic ground state with the desired properties of each constituent: polar and ferrimagnetic due to BiFeO3 and BiMnO3, respectively. The effect of B-site cation ordering on magnetic ordering in the BiFeO3-BiMnO3 system is studied. The checkerboard ge...

Preparation and magnetic properties of anisotropic bulk MnBi/NdFeB hybrid magnets

Science.gov (United States)

Ma, Y. L.; Liu, X. B.; Nguyen, V. V.; Poudyal, N.; Yue, M.; Liu, J. P.

2016-08-01

Anisotropic hybrid bulk magnets of MnBi/NdFeB with different composition ratio have been prepared with starting MnBi and Nd2Fe14B powders as well as epoxy resin as a binder in case it is needed to form bulk samples. It has been found that the ratio between the two phases in content has a remarkable influence on the magnetic properties, the thermal stability and the density of the bulk magnets. With increasing MnBi content the binder addition can be reduced. When the MnBi content is larger than 30 wt%, no binder is needed. On the other hand, the coercivity and saturation magnetization were increased significantly with increasing NdFeB content. When the NdFeB content was increased from 0% to 50%, the maximum energy product was enhanced from 4.7 to 10.0 MGOe, respectively. The energy product then decreased gradually with the NdFeB content due to the reduced density of the hybrid magnet. The thermal stability measurements showed that the temperature coefficient of coercivity grew with the MnBi content and became positive with MnBi=80 wt%.

In-situ synthesis of nanofibers with various ratios of BiOCl{sub x}/BiOBr{sub y}/BiOI{sub z} for effective trichloroethylene photocatalytic degradation

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yifan [Department of Chemistry, Inha University, 100 Inharo, Incheon 402-751 (Korea, Republic of); Park, Mira [Department of Organic Materials and Fiber Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Kim, Hak Yong [Department of BIN Convergence Technology, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Ding, Bin [College of Textiles, Donghua University, Shanghai 201620 (China); Park, Soo-Jin, E-mail: sjpark@inha.ac.kr [Department of Chemistry, Inha University, 100 Inharo, Incheon 402-751 (Korea, Republic of)

2016-10-30

Highlights: • BiOCl{sub x}/BiOBr{sub y}/BiOI{sub z}/PAN fibers were synthesized by in-situ method. • Photodegradation behavior of BiOCl{sub x}/BiOBr{sub y}/BiOI{sub z}/PAN fibers was measured under solar light irradiation. • BiOCl{sub 0.3}/BiOBr{sub 0.3}/BiOI{sub 0.4}/PAN fibers exhibited the highest photocatalytic activity. • Photocatalytic mechanism was discussed in detail. - Abstract: In this work, BiOCl{sub x}/BiOBr{sub y}/BiOI{sub z} (x + y + z = 1) composite nanofibers were prepared through electrospinning and the sol-gel methods. Photocatalytic degradation of trichloroethylene (TCE) by BiOCl{sub x}/BiOBr{sub y}/BiOI{sub z}/PAN nanofibers was systematically investigated via gas chromatography (GC). Optimum photocatalytic activity was achieved with BiOCl{sub 0.3}/BiOBr{sub 0.3}/BiOI{sub 0.4} fibers under solar light irradiation. X-ray photoelectron spectroscopy (XPS) peaks due to C−O and C=O were observed at 286.0 and 288.3 eV, respectively, it indicated that the BiOCl{sub x}/BiOBr{sub y}/BiOI{sub z} mixture had been successfully doped on the polyacrylonitrile (PAN) fibers. Furthermore, X-ray diffraction (XRD) results also confirmed that we had synthesized the as-prepared composite nanofibers successfully. Photocatalytic activities of BiOCl{sub 0.3}/BiOBr{sub 0.3}/BiOI{sub 0.4} were up to 3 times higher than the pure BiOCl, BiOBr and BiOI samples, respectively.

Rapid adsorption properties of flower-like BiOI nanoplates synthesized via a simple EG-assisted solvothermal process

Energy Technology Data Exchange (ETDEWEB)

Zhang, Bin; Ji, Guangbin, E-mail: gbji@nuaa.edu.cn [Nanjing University of Aeronautics and Astronautics, College of Materials Science and Technology (China); Gondal, M. A. [King Fahd University of Petroleum and Minerals, Physics Department (Saudi Arabia); Liu, Yousong; Zhang, Xingmiao; Chang, Xiaofeng; Li, Nianwu [Nanjing University of Aeronautics and Astronautics, College of Materials Science and Technology (China)

2013-07-15

Uniform well-crystallized flower-like BiOI nanoplates contained 3.7 nm mesopores, which may be attributed to the internanosheet spaces of BiOI with maximum pore diameters of about 30 nm, were successfully synthesized via a simple ethylene glycol-assisted solvothermal method. The as-prepared porous BiOI nanoplates exhibited excellent adsorption ability, and the saturated extent of adsorption of BiOI over an RhB solution was as high as 197 mg/g, which is much higher than those for BiOCl and BiOBr prepared via the same method and with a similar surface area. The probable adsorption mechanism could have originated from the interaction between the I atom in BiOI and a proton in RhB at different pH values and temperatures. With visible light irradiation ({lambda} > 420 nm), 80 % of the RhB was degraded in 4 h, while BiOI still demonstrated reasonably outstanding photocatalytic ability under green light ({lambda} = 550 {+-} 15 nm) because of its low-energy gap (1.72 eV). The degradation test for BiOI under irradiation at {lambda} = 550 {+-} 15 nm is an excellent achievement for field applications because the catalyst can be applied in solar irradiation to remove organic pollutants, which may be of great value BiOI complex.

Bi-directional magnetic resonance based wireless power transfer for electronic devices

International Nuclear Information System (INIS)

Kar, Durga P.; Nayak, Praveen P.; Bhuyan, Satyanarayan; Mishra, Debasish

2015-01-01

In order to power or charge electronic devices wirelessly, a bi-directional wireless power transfer method has been proposed and experimentally investigated. In the proposed design, two receiving coils are used on both sides of a transmitting coil along its central axis to receive the power wirelessly from the generated magnetic fields through strongly coupled magnetic resonance. It has been observed experimentally that the maximum power transfer occurs at the operating resonant frequency for optimum electric load connected across the receiving coils on both side. The optimum wireless power transfer efficiency is 88% for the bi-directional power transfer technique compared 84% in the one side receiver system. By adopting the developed bi-directional power transfer method, two electronic devices can be powered up or charged simultaneously instead of a single device through usual one side receiver system without affecting the optimum power transfer efficiency

Bi-directional magnetic resonance based wireless power transfer for electronic devices

Energy Technology Data Exchange (ETDEWEB)

Kar, Durga P.; Nayak, Praveen P.; Bhuyan, Satyanarayan; Mishra, Debasish [Department of Electronics and Instrumentation Engineering, Institute of Technical Education and Research, Siksha ‘O’ Anushandhan University, Bhubaneswar 751030 (India)

2015-09-28

In order to power or charge electronic devices wirelessly, a bi-directional wireless power transfer method has been proposed and experimentally investigated. In the proposed design, two receiving coils are used on both sides of a transmitting coil along its central axis to receive the power wirelessly from the generated magnetic fields through strongly coupled magnetic resonance. It has been observed experimentally that the maximum power transfer occurs at the operating resonant frequency for optimum electric load connected across the receiving coils on both side. The optimum wireless power transfer efficiency is 88% for the bi-directional power transfer technique compared 84% in the one side receiver system. By adopting the developed bi-directional power transfer method, two electronic devices can be powered up or charged simultaneously instead of a single device through usual one side receiver system without affecting the optimum power transfer efficiency.

Piezoelectric properties enhanced of Sr0.6(BiNa)0.2Bi2Nb2O9 ceramic by (LiCe) modification with charge neutrality

International Nuclear Information System (INIS)

Fang, Pinyang; Xi, Zengzhe; Long, Wei; Li, Xiaojuan; Li, Jin

2013-01-01

Graphical abstract: The oxygen vacancies were confirmed by the left figure. The role of oxygen vacancy on piezoelectric activities was obtained by comparing to the varieties of oxygen vacancy concentration and piezoelectric coefficient with (LiCe) modification. -- Highlights: • The Sr 0.6 (BiNa) 0.2 Bi 2 Nb 2 O 9 ceramic by (LiCe) modification with the charge neutrality was synthesized by the solid state reaction method. • The Curie temperature and piezoelectric coefficient were found to be T c ∼590 °C and d 33 ∼32 pC/N, respectively. • The mechanism of piezoelectric activities improved by (LiCe) modification was discussed. -- Abstract: Aurivillius-type ceramics, Sr 0.6−x (LiCe) x/2.5 (BiNa) 0.2 Bi 2 Nb 2 O 9 (SLCBNBNO) with the charge neutrality, were synthesized by using conventional solid-state processing. Phase analysis was performed by X-ray diffraction analyses (XRD) and Raman spectroscopy. Microstructural morphology was assessed by the scanning electron microscopy (SEM). Structural, dielectric, piezoelectric, ferroelectric, and electromechanical properties of the SLCBNBNO ceramics were investigated. Piezoelectric properties were significantly enhanced compared to Sr 0.6 (BiNa) 0.2 Bi 2 Nb 2 O 9 (SBNBN) ceramic and the maximum of piezoelectric coefficient d 33 of the SBNBN-LC6 ceramic was 32 pC/N with higher Curie temperature (T c ∼590 °C). In addition, mechanisms for the piezoelectric properties enhanced of the SBNBN-based ceramics were discussed

Thermal expansion properties of Bi-2212 in Ag or an Ag-alloy matrix

International Nuclear Information System (INIS)

Tenbrink, J.; Krauth, H.

1994-01-01

The thermal expansion properties of polycrystalline Bi 2 Sr 2 Ca 1 Cu 2 O 8+x melt-processed bulk specimens, and Bi 2 Sr 2 Ca 1 Cu 2 O 8+x monocore as well as multifilamentary round wires in Ag or Ag-alloy matrix have been investigated over the temperature range from -150 to 800 degrees C. Although the thermal expansion of Bi 2 Sr 2 Ca 1 Cu 2 O 8+x is distinctly lower compared with Ag, the thermal expansion properties of the Bi 2 Sr 2 Ca 1 Cu 2 O 8+x -Ag or AgNiMg-alloy composite conductors are essentially governed by the matrix material. The thermal expansion of the encountered oxide-dispersion-strengthened AgNiMg alloys is only slightly lower compared with that of pure Ag. Therefore the thermal expansion of all investigated Bi 2 Sr 2 Ca 1 Cu 2 O 8+x -Ag or Ag-alloy composite wires was found to be close to that of pure Ag. The reason for this striking behaviour is shown to be related to a surprisingly low elastic modulus of the polycrystalline Bi-2212 wire cores of the order of 10 to a maximum 40 GPa. (author)

1D chain formation by coadsorption of Pb and Bi on Cu(001): Determination using low energy electron diffraction

Science.gov (United States)

Kabiruzzaman, Md; Ahmed, Rezwan; Nakagawa, Takeshi; Mizuno, Seigi

2017-10-01

Coadsorption of two heavy metals, Pb and Bi, on Cu(001) at room temperature has been studied using low energy electron diffraction (LEED). c(4 × 4), c(2 × 2), and c(9√{ 2}×√{ 2}) phases are obtained at different coverages; here, we have determined the best-fit structure of c(4 × 4) phase. This structure can be described as a 1D substitutional chain arrangement of Pb and Bi atoms between the Cu rows along the [110] direction. The unit cell in the two-dimensional (2D) surface consists of one Bi atom, two Pb atoms, and four Cu atoms with one vacancy at the center. The optimal structure parameters demonstrate that Bi atoms are located at fourfold-hollow sites and that Pb atoms are laterally displaced by 0.78 Å from the fourfold-hollow site toward the vacancy. The reasons for the formation of the c(4 × 4) structure upon deposition of Pb and Bi on Cu(001) are discussed in comparison with a similar structure formed by the individual adsorption of Pb on the same substrate.

Facile Fabrication of BiOI/BiOCl Immobilized Films With Improved Visible Light Photocatalytic Performance

Directory of Open Access Journals (Sweden)

Yingxian Zhong

2018-03-01

Full Text Available HIGHLIGHTSA facial method was used to fabricate BiOI/BiOCl film at room temperature.30% BiOI/BiOCl showed an excellent photocatalytic activity and stability.Improvement of photocatalytic activity was owed to expanded visible light absorption and high separation efficiency of charge.Photocatalysis has been considered to be one of the most promising ways to photodegrade organic pollutants. Herein, a series of BiOI/BiOCl films coating on FTO were fabricated through a simple method at room temperature. The photocatalytic efficiency of 30%BiOI/BiOCl could reach more than 99% aiming to degrading RhB and MB after 90 and 120 min, respectively. Compared with BiOCl, 30%BiOI/BiOCl showed 12 times higher efficiency when degrading RhB. In comparison with BiOI, 30%BiOI/BiOCl showed 5 and 6 times higher efficiency when degrading RhB and MB, respectively. These obvious enhancements were attributed to expanded visible light absorption and high separation performance of photoinduced charge. Moreover, the photocatalytic activity of 30%BiOI/BiOCl had no obvious decrease after five recycles, suggesting that it was a promising photocatalyst for the removal of MB and RhB pollutants. Finally, the possible growth process for the BiOI/BiOCl thin films and photocatalysis mechanism were investigated in details. This work would provide insight to the reasonable construction of BiOX heterojunction and the photocatalytic mechanism in degrading organic pollutants.

Influence of photoinduced Bi-related self-doping on the photocatalytic activity of BiOBr nanosheets

Energy Technology Data Exchange (ETDEWEB)

Wu, Dan [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR (China); Yue, Songtao; Wang, Wei [College of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); An, Tiacheng, E-mail: antc99@gig.ac.cn [Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Li, Guiying [Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Ye, Liqun [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR (China); College of Chemistry and Pharmaceutical Engineering, Nanyang Normal University, Nanyang 473061 (China); Yip, Ho Yin [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR (China); Wong, Po Keung, E-mail: pkwong@cuhk.edu.hk [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR (China)

2017-01-01

Highlights: • Bi{sup 5+} self-doped BiOBr nanosheets are achieved under UV irradiation. • Bi{sup 5+} is formed due to the oxidation of surface Bi{sup 3+} by photoexcited h{sup +} of BiOBr. • Two photoinduced h{sup +} mediated oxidation processes happen simultaneously. • Self-doped BiOBr is superior in phenol degradation and bacterial inactivation. • Bi{sup 5+} electron trapping induced photocatalytic enhancement mechanism is proposed. - Abstract: Under UV irradiation, self-doped Bi{sup 5+} is evidenced to be generated on the surface of BiOBr nanosheets, but with well-preserved crystal structure and morphology compared with pure counterpart. Bi{sup 5+} self-doping BiOBr (BiOBr-4) exhibits distinct photocatalytic mode for dyes degradation, as compared with pure BiOBr nanosheets. These photodegradation distinctions are mainly due to the simultaneous occurrence of two photoinduced hole (h{sup +}) mediated oxidation processes on the BiOBr surfaces: (1) a portion of photoexcited h{sup +} participates in the photocatalytic oxidation of dyes, and (2) partial h{sup +} involves the oxidation of Bi{sup 3+} to Bi{sup 5+}. Notably, BiOBr-4 nanosheets comparatively show superior photocatalytic activity for the phenol decomposition as well as the bacterial inactivation. Besides Bi{sup 5+} induced narrowed bandgap and enhanced light adsorption capacity, significantly, the oxidative Bi{sup 5+} acts as electron traps to promote the photoexcited electron-hole separation and accelerate h{sup +} migration, resulting in the considerable photocatalytic enhancement of BiOBr-4 nanosheets. These novel findings will not only give new insights into the photocatalytic mechanism but also explore new route to enhance photocatalytic performance of Bi-based materials.

Anomalous Anisotropic Magnetoresistance And Magnetization In Mn3.69Bi95.69Fe0.62

Directory of Open Access Journals (Sweden)

A. V. Terekhov

2017-12-01

Full Text Available It was found that the Mn3.69Bi95.69Fe0.62 consists of two phases, namely of a bismuth matrix and BiMn inclusions. It is shown that the samples have a crystalline texture. Independently on the applied field orientation, maximum on the temperature dependence of magnetization is detected at Tmax ≈ 85 K, which is associated with the reorientation transition of the magnetic moments of Mn for αBiMn phase. In turn, the electrical resistivity ρ(T also demonstrates maximum at Tmax ≈58 K in a magnetic field of 800 kA/m when H⊥I. It is established that the maximum of ρ(T increases and is shifted toward higher temperature Tmax≈94 K when field increasing up to 2400 kA/m. At the same time no clear maximum on ρ(T is observed for H||I. It is shown that the relative magnetoresistance, Δρ/ρ0, is increased both with decreasing temperature and with increase of the magnetic field. The measured enhancement reaches Δρ/ρ0≈250% for H||I and Δρ/ρ0≈2400% for H⊥I in magnetic field of 2400 kA/m. Thus, the strong anisotropy of ρ(T and Δρ/ρ0(T is established both for H⊥I and H||I. Possible explanation of observed anomalous behavior of the temperature dependences of the electrical resistivity in magnetic fields has been proposed.

Enhancing Coverage in Narrow Band-IoT Using Machine Learning

OpenAIRE

Chafii , Marwa; Bader , Faouzi; Palicot , Jacques

2018-01-01

International audience; —Narrow Band-Internet of Thing (NB-IoT) is a recently proposed technology by 3GPP in Release-13. It provides low energy consumption and wide coverage in order to meet the requirements of its diverse applications that span social, industrial and environmental aspects. Increasing the number of repetitions of the transmission has been selected as a promising approach to enhance the coverage in NB-IoT up to 164 dB in terms of maximum coupling loss for uplink transmissions,...

TbxBi1-xFeO3 nanoparticulate multiferroics fabricated by micro-emulsion technique: Structural elucidation and magnetic behavior evaluation

KAUST Repository

Anwar, Zobia

2014-04-01

Tb-doped BiFeO3 multiferroics nanoparticles fabricated via micro-emulsion route were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The fully characterized TbxBi1-xFeO3 nanoparticles were then subjected to magnetic behavior evaluation for various technological applications. The thermogravimetric analysis (TGA) conducted in the range 25-1000 C predicted the temperature (~960 C) for phase formation. XRD estimated the crystallite size 30-47 nm, while the particles size estimated by SEM was found (80-120 nm). The XRD data confirmed the rhombohedral (space group R3c) phase with average cell volume 182.66 Å3 (for BiFeO 3). Various other physical parameters like bulk density, X-ray density and porosity were also determined from the XRD data and found in agreement with theoretical predictions. The magnetic studies showed that as Bi3+ was substituted by Tb3+, all magnetic parameters were altered. The maximum saturation magnetization (Ms) (0.6691 emug -1) was exhibited by Tb0.02Bi0.98FeO 3 while the Tb0.00Bi1.00Fe1.00O 3 showed the maximum (549 Oe) coercivity. The evaluated magnetic behavior categorized these materials as soft magnetic materials that may be useful for fabricating advanced technological applications. © 2013 Elsevier B.V.

Bi3+–Pr3+ energy transfer processes and luminescent properties of LuAG:Bi,Pr and YAG:Bi,Pr single crystalline films

International Nuclear Information System (INIS)

Zorenko, Y.; Gorbenko, V.; Savchyn, V.; Zorenko, T.; Nikl, M.; Mares, J.A.; Beitlerova, A.; Jary, V.

2013-01-01

Absorption, cathodoluminescence, excitation spectra of photoluminescence (PL) and PL decay kinetics were studied at 300 K for the double doped with Bi 3+ –Pr 3+ and separately doped with Bi 3+ and Pr 3+ Lu 3 Al 5 O 12 (LuAG) and Y 3 Al 5 O 12 (YAG) single crystalline film (SCF) phosphors grown by the liquid phase epitaxy method. The emission bands in the UV range arising from the intrinsic radiative transitions of Bi 3+ based centers, and emission bands in the visible range, related to the luminescence of excitons localized around Bi 3+ based centers, were identified both in Bi–Pr and Bi-doped LuAG and YAG SCFs. The energy transfer processes from the host lattice simultaneously to Bi 3+ and Pr 3+ ions and from Bi 3+ to Pr 3+ ions were investigated. Competition between Pr 3+ and Bi 3+ ions in the energy transfer processes from the LuAG and YAG hosts was evidenced. The strong decrease of the intensity of Pr 3+ luminescence both in LuAG:Pr and YAG:Pr SCFs phosphors, grown from Bi 2 O 3 flux, is observed due to the quenching influence of Bi 3+ flux related impurity. Due to overlap of the UV emission band of Bi 3+ centers with the f–d absorption bands of Pr 3+ ions in the UV range and the luminescence of excitons localized around Bi ions with the f–f absorption bands of Pr 3+ ions in the visible range, an effective energy transfer from Bi 3+ ions to Pr 3+ ions takes place in LuAG:Bi,Pr and YAG:Bi,Pr SCFs, resulting in the appearance of slower component in the decay kinetics of the Pr 3+ d–f luminescence. -- Highlights: • Bi and Pr doped film phosphor grown by liquid phase epitaxy method. • Energy transfer from Bi 3+ to Pr 3+ ions. • Strong quenching of the Pr 3+ luminescence by Bi 3+ co-dopant

Facile Fabrication of BiOI/BiOCl Immobilized Films with Improved Visible Light Photocatalytic Performance

Science.gov (United States)

Zhong, Yingxian; Liu, Yuehua; Wu, Shuang; Zhu, Yi; Chen, Hongbin; Yu, Xiang; Zhang, Yuanming

2018-03-01

Photocatalysis has been considered to be one of the most promising ways to photodegrade organic pollutants. Herein, a series of BiOI/BiOCl films coating on FTO were fabricated through a simple method at room temperature. The photocatalytic efficiency of 30%BiOI/BiOCl could reach more than 99% aiming to degrading RhB and MB after 90 and 120 min, respectively. Compared with BiOCl, 30%BiOI/BiOCl showed 12 times higher efficiency when degrading RhB. In comparison with BiOI, 30%BiOI/BiOCl showed 5 and 6 times higher efficiency when degrading RhB and MB, respectively. These obvious enhancements were attributed to expanded visible light absorption and high separation performance of photoinduced charge. Moreover, the photocatalytic activity of 30%BiOI/BiOCl had no obvious decrease after 5 recycles, suggesting that it was a promising photocatalyst for the removal of MB and RhB pollutants. Finally, the possible growth process for the BiOI/BiOCl thin films and photocatalysis mechanism were investigated in details. This work would provide insight to the reasonable construction of BiOX heterojunction and the photocatalytic mechanism in degrading organic pollutants.

Optimized electrode coverage of membrane actuators based on epitaxial PZT thin films

International Nuclear Information System (INIS)

Nguyen, M D; Dekkers, M; Blank, D H A; Rijnders, G; Nazeer, H

2013-01-01

This research presents an optimization of piezoelectric membrane actuators by maximizing the actuator displacement. Membrane actuators based on epitaxial Pb(Zr,Ti)O 3 thin films grown on all-oxide electrodes and buffer layers using silicon technology were fabricated. Electrode coverage was found to be an important factor in the actuation displacement of the piezoelectric membranes. The optimum electrode coverage for maximum displacement was theoretically determined to be 39%, which is in good agreement with the experimental results. Dependences of membrane displacement and optimum electrode coverage on membrane diameter and PZT-film/Si-device-layer thickness ratio have also been investigated. (paper)

Synthesis and magnetic properties of the thin film exchange spring system of MnBi/FeCo

Science.gov (United States)

Sabet, S.; Hildebrandt, E.; Alff, L.

2017-10-01

Manganese bismuth thin films with a nominal thickness of ∼40 nm were grown at room temperature onto quartz glass substrate in a DC magnetron sputtering unit. In contrast to the usual multilayer approach, the MnBi films were deposited using a single sputtering target with a stoichiometry of Mn55Bi45 (at. %). A subsequent in-situ annealing step was performed in vacuum in order to form the ferromagnetic LTP of MnBi. X-ray diffraction confirmed the formation of a textured LTP MnBi hard phase after annealing at 330 °C. This film shows a maximum saturation magnetization of 530 emu/cm3, high out-of-plane coercivity of 15 kOe induced by unreacted bismuth. The exchange coupling effect was investigated by deposition of a second layer of FeCo with 1 nm and 2 nm thickness onto the LTP MnBi films. The MnBi/FeCo double layer showed as expected higher saturation magnetization with increasing thickness of the FeCo layer while the coercive field remained constant. The fabrication of the MnBi/FeCo double layer for an exchange spring magnet was facilitated by deposition from a single stoichiometric target.

On the electronic structure and thermoelectric properties of BiTeBr and BiTeI single crystals and of BiTeI with the addition of BiI3 and CuI

International Nuclear Information System (INIS)

Kulbachinskii, Vladimir A.; Kytin, Vladimir G.; Kudryashov, Alexey A.; Kuznetsov, Alexei N.; Shevelkov, Andrei V.

2012-01-01

The electronic structures were calculated for BiTeBr and BiTeI using the density-functional theory approach and accounting for the strong spin–orbital interaction. Qualitatively, the band structures for two compounds are similar, showing strong mixing of the p states of all elements in vicinity of the Fermi level, with the band gaps of 0.595 and 0.478 eV for BiTeBr and BiTeI, respectively. The optimized crystal structures show a tendency for the Bi–X (X=Br, I) bond elongation compared to the Bi–Te one. Both compounds are intrinsic n-type semiconductors but display a metallic-like conductivity coupled to rather large thermopower, which is rationalized within the frames of the acoustic phonons scattering model. Because of larger thermopower BiTeBr exhibits a twice higher thermoelectric figure-of-merit near room temperature, ZT=0.17, compared to BiTeI. The addition of 1 mass% of BiI 3 or CuI to BiTeI decreases the mobility of electrons by two orders of magnitude, leading to significantly lower electrical conductivity, but at the same time effectively reduces the thermal conductivity. The prospects of further enhancing the thermoelectric efficiency are briefly discussed. - Graphical abstract: View of the crystal structure of BiTeBr is shown in the figure The optimized crystal structures show a tendency for the Bi–X (X=Br, I) bond elongation compared to the Bi–Te one. The electronic structures were calculated for BiTeBr and BiTeI using the density-functional theory approach and accounting for the strong spin–orbital interaction. Qualitatively, the band structures for two compounds are similar, showing strong mixing of the p states of all elements in vicinity of the Fermi level, with the band gaps of 0.595 and 0.478 eV for BiTeBr and BiTeI, respectively. Both compounds are intrinsic n-type semiconductors but display a metallic-like conductivity coupled to rather large thermopower, which is rationalized within the frames of the acoustic phonons scattering

Preparation and magnetic properties of anisotropic bulk MnBi/NdFeB hybrid magnets

International Nuclear Information System (INIS)

Ma, Y.L.; Liu, X.B.; Nguyen, V.V.; Poudyal, N.; Yue, M.; Liu, J.P.

2016-01-01

Anisotropic hybrid bulk magnets of MnBi/NdFeB with different composition ratio have been prepared with starting MnBi and Nd 2 Fe 14 B powders as well as epoxy resin as a binder in case it is needed to form bulk samples. It has been found that the ratio between the two phases in content has a remarkable influence on the magnetic properties, the thermal stability and the density of the bulk magnets. With increasing MnBi content the binder addition can be reduced. When the MnBi content is larger than 30 wt%, no binder is needed. On the other hand, the coercivity and saturation magnetization were increased significantly with increasing NdFeB content. When the NdFeB content was increased from 0% to 50%, the maximum energy product was enhanced from 4.7 to 10.0 MGOe, respectively. The energy product then decreased gradually with the NdFeB content due to the reduced density of the hybrid magnet. The thermal stability measurements showed that the temperature coefficient of coercivity grew with the MnBi content and became positive with MnBi=80 wt%. - Highlights: • Anisotropic bulk hybrid MnBi/NdFeB magnets were prepared. • MnBi content affected the density and coercivity temperature coefficient positively. • An energy product (BH) max of 10 MGOe was obtained at NdFeB content of 50 wt%.

Preparation and magnetic properties of anisotropic bulk MnBi/NdFeB hybrid magnets

Energy Technology Data Exchange (ETDEWEB)

Ma, Y.L. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); College of Metallurgical and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Liu, X.B.; Nguyen, V.V.; Poudyal, N. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); Yue, M. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Liu, J.P., E-mail: pliu@uta.edu [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

2016-08-01

Anisotropic hybrid bulk magnets of MnBi/NdFeB with different composition ratio have been prepared with starting MnBi and Nd{sub 2}Fe{sub 14}B powders as well as epoxy resin as a binder in case it is needed to form bulk samples. It has been found that the ratio between the two phases in content has a remarkable influence on the magnetic properties, the thermal stability and the density of the bulk magnets. With increasing MnBi content the binder addition can be reduced. When the MnBi content is larger than 30 wt%, no binder is needed. On the other hand, the coercivity and saturation magnetization were increased significantly with increasing NdFeB content. When the NdFeB content was increased from 0% to 50%, the maximum energy product was enhanced from 4.7 to 10.0 MGOe, respectively. The energy product then decreased gradually with the NdFeB content due to the reduced density of the hybrid magnet. The thermal stability measurements showed that the temperature coefficient of coercivity grew with the MnBi content and became positive with MnBi=80 wt%. - Highlights: • Anisotropic bulk hybrid MnBi/NdFeB magnets were prepared. • MnBi content affected the density and coercivity temperature coefficient positively. • An energy product (BH){sub max} of 10 MGOe was obtained at NdFeB content of 50 wt%.

Preparation, characterization and enhanced visible-light photocatalytic activities of BiPO4/BiVO4 composites

International Nuclear Information System (INIS)

Wu, Siyuan; Zheng, Hong; Lian, Youwei; Wu, Yiying

2013-01-01

Graphical abstract: - Highlights: • BiPO 4 /BiVO 4 composites were successfully prepared by the hydrothermal method. • BiPO 4 /BiVO 4 composites exhibited broad absorption in the visible region. • Visible-light photocatalytic activities of BiPO 4 /BiVO 4 composites were enhanced. • P/V molar ratio and pH value of the reaction affect photocatalytic activity. • The mechanism of enhanced visible-light photocatalytic activities was discussed. - Abstract: BiPO 4 /BiVO 4 composites with different P/V molar ratios were prepared by the hydrothermal method and the effect of pH values of hydrothermal reaction on photocatalytic activity of BiPO 4 /BiVO 4 composite was investigated. The photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance spectroscopy. The photocatalytic property of BiPO 4 /BiVO 4 was evaluated by photocatalytic degradation of Methylene blue under visible light irradiation. The results showed that the photocatalytic activity of the composites was much higher than that of pure BiPO 4 and BiVO 4 . The rate constant of Methylene blue degradation over BiPO 4 /BiVO 4 (P/V molar ratio of 5:1 and hydrothermal reaction pH value of 1.5) is 1.7 times that of pure BiVO 4 . The photocatalytic activity enhancement of BiPO 4 /BiVO 4 composite is closely related to the BiVO 4 functioning as a sensitizer to adsorb visible light and the heterojunction of BiPO 4 /BiVO 4 acting as an active center for hindering the rapid recombination of electron–hole pairs during the photocatalytic reaction

Spatial profile of thermoelectric effects during Peltier pulsing in Bi and Bi/MnBi eutectic

Science.gov (United States)

Silberstein, R. P.; Larson, D. J., Jr.

1987-01-01

The spatial profile of the thermal transients that occur during and following the current pulsing associated with Peltier Interface Demarcation during directional solidification is studied. Results for pure Bi are presented in detail and compared with corresponding results for the Bi/MnBi eutectic. Significant thermal transients occur throughout the sample that can be accounted for by the Peltier effect, the Thomson effect, and Joule heating. These effects are separated and their behavior is studied as a function of time, current density, and position with respect to the solid/liquid interface.

State diagram of Pr-Bi system

International Nuclear Information System (INIS)

Abulkhaev, V.L.; Ganiev, I.N.

1994-01-01

By means of thermal differential analysis, X-ray and microstructural analysis the state diagram of Pr-Bi system was studied. Following intermetallic compounds were defined in the system: Pr 2 Bi, Pr 5 Bi 3 , Pr 4 Bi 3 , Pr Bi, PrBi 2 , Pr 2 Bi, Pr 5 Bi 3 , Pr 4 Bi 3 and PrBi 2 . The data analysis on Ln-Bi diagram allowed to determine the regularity of change of properties of intermetallic compounds in the line of rare earth elements of cerium subgroup.

Investigation of bi-enzymatic reactor based on hybrid monolith with nanoparticles embedded and its proteolytic characteristics.

Science.gov (United States)

Shangguan, Lulu; Zhang, Lingyi; Xiong, Zhichao; Ren, Jun; Zhang, Runsheng; Gao, Fangyuan; Zhang, Weibing

2015-04-03

The bottom-up strategy of proteomic profiling study based on mass spectrometer (MS) has drawn high attention. However, conventional solution-based digestion could not satisfy the demands of highly efficient and complete high throughput proteolysis of complex samples. We proposed a novel bi-enzymatic reactor by immobilizing two different enzymes (trypsin/chymotrypsin) onto a mixed support of hybrid organic-inorganic monolith with SBA-15 nanoparticles embedded. Typsin and chymotrypsin were crossly immobilized onto the mixed support by covalent bonding onto the monolith with glutaraldehyde as bridge reagent and chelation via copper ion onto the nanoparticles, respectively. Compared with single enzymatic reactors, the bi-enzymatic reactor improved the overall functional analysis of membrane proteins of rat liver by doubling the number of identified peptides (from 1184/1010 with trypsin/chymotrypsin enzymatic reactors to 2891 with bi-enzymatic reactor), which led to more proteins identified with deep coverage (from 452/336 to 620); the efficiency of the bi-enzymatic reactor is also better than that of solution-based tandem digestion, greatly shorting the digestion time from 24h to 50s. Moreover, more transmembrane proteins were identified by bi-enzymatic reactor (106) compared with solution-based tandem digestion (95) with the same two enzymes and enzymatic reactors with single enzyme immobilized (75 with trypsin and 66 with chymotrypsin). The proteolytic characteristics of the bi-enzymatic reactors were evaluated by applying them to digestion of rat liver proteins. The reactors showed good digestion capability for proteins with different hydrophobicity and molecular weight. Copyright © 2015 Elsevier B.V. All rights reserved.

Fabrication of Ba-K-Bi-O thick film artefacts with improved critical currents

International Nuclear Information System (INIS)

Moore, J.C.; Salter, C.J.; Jenkins, R.J.; Grovenor, C.R.M.; Jones, H.

1993-01-01

The Ba-K-Bi-O system has a maximum T c of around 30K for a composition of Ba 0.6 K 0.4 BiO 3 . Fabrication of good quality single phase samples is extremely difficult and requires careful control of the fabrication conditions. Successful synthesis procedures for Ba-K-Bi-O powder and melt cast material which allow some control of the potassium content of the product were established by Hinks et al. The process is based on a melt and sinter step in an inert atmosphere which creates oxygen vacancies and allows potassium to enter the lattice. The oxygen vacancies are then filled by a subsequent oxygen anneal to obtain superconductivity. Ba-K-Bi-O is, therefore, metastable and consequently difficult to synthesise. There have been few reports of transport measurements and even fewer reports of transport critical currents for bulk material. It is often accepted that Ba-K-Bi-O has an intrinsically low critical current, and extremely poor critical current densities of 0.05 Acm -2 have been quoted for melt cast material. It has been suggested that the presence of weak links is the cause. However, there has been little research into the relationship between process conditions and superconducting properties for melt processed Ba-K-Bi-O to confirm this. (orig.)

LA phonons scattering of surface electrons in Bi{sub 2}Se{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Huang, Lang-Tao [State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084 (China); Zhu, Bang-Fen [State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China and Institute of Advanced Study, Tsinghua University, Beijing 100084 (China)

2013-12-04

Within the Boltzmann equation formalism we evaluate the transport relaxation time of Dirac surface states (SSs) in the typical topological insulator(TI) Bi{sub 2}Se{sub 3} due to the phonon scattering. We find that although the back-scattering of the SSs in TIs is strictly forbidden, the in-plane scattering between SSs in 3-dimensional TIs is allowed, maximum around the right-angle scattering. Thus the topological property of the SSs only reduces the scattering rate to its one half approximately. Besides, the larger LA deformation potential and lower sound velocity of Bi{sub 2}Se{sub 3} enhance the scattering rate significantly. Compared with the Dirac electrons in graphene, we find the scattering rate of SSs in Bi{sub 2}Se{sub 3} are two orders of magnitudes larger, which agree with the recent transport experiments.

Enhanced Photoluminescence of Sm3+/Bi3+ Co-Doped La2O3 Nanophosphors by Combustion Synthesis

Science.gov (United States)

Zhang, Ying; Wu, Muying; Zhang, W. F.

Nanosized La2O3:Sm3+ and La2O3:Sm3+, Bi3+ phosphor powders were prepared via combustion synthesis. The structures and morphology were examined using powder X-ray diffraction and transmission electron microscope, respectively. The photoluminescence spectra were investigated at different doping concentrations of Sm3+ and Bi3+ ions. The results indicate that La2O3:Sm3+ (Bi3+) exhibited good crystallinity and spherical-like particles. All phosphors give emission bands centered at 564, 608 and 650 nm corresponding to 4G5/2→6HJ (J=5/2, 7/2 and 9/2) transitions of Sm3+ ions, respectively. Interestingly, the emission intensity of Sm3+ ions is significantly enhanced with the addition of Bi3+ ions to La2O3:Sm3+ and the maximum occurs at a Bi3+ concentration of 0.8 mol%. The La2O3:Sm3+, Bi3+ phosphor with highly enhanced luminescence is very encouraging for applications in display and tunable solid lasers.

One-step growth of nanosheet-assembled BiOCl/BiOBr microspheres for highly efficient visible photocatalytic performance

Science.gov (United States)

Zhang, Jinfeng; Lv, Jiali; Dai, Kai; Liang, Changhao; Liu, Qi

2018-02-01

In this work, we have developed a simple synthetic approach of nanosheet-assembled BiOCl/BiOBr microspheres by an ethylene glycol (EG)-assisted hydrothermal method. The crystalline form, morphology, chemical composition, optical performance and surface area of BiOCl/BiOBr microspheres were identified using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy spectra (EDX), UV-vis diffuse reflectance spectroscopy (DRS) analysis, high resolution X-ray photoelectron spectra (XPS) and N2 adsorption-desorption isotherms. BiOCl/BiOBr microspheres were nanosheet-assembled particles, which possessed visible light absorption under LED light irridation. Additionally, the methylene blue (MB) photodegradation performance of different BiOCl/BiOBr microspheres irradiated under 410 nm LED light arrays were investigated, the results exhibited that as-prepared BiOCl/BiOBr products showed higher catalytic effiency than pure BiOCl or BiOBr. By optimizing the composition ration of the BiOCl and BiOBr, up to 93% degradation rate can be obtained in the 40%BiOCl/BiOBr microspheres. Finally, the photocatalytic mechanism of BiOCl/BiOBr microspheres had been proposed.

Off-Center Rotation of CuPc Molecular Rotor on a Bi(111) Surface and the Chiral Feature.

Science.gov (United States)

Sun, Kai; Tao, Min-Long; Tu, Yu-Bing; Wang, Jun-Zhong

2017-05-04

Molecular rotors with an off-center axis and the chiral feature of achiral CuPc molecules on a semi-metallic Bi(111) surface have been investigated by means of a scanning tunneling microscopy (STM) at liquid nitrogen (LN₂) temperature. The rotation axis of each CuPc molecular rotor is located at the end of a phthalocyanine group. As molecular coverage increases, the CuPc molecules are self-assembled into various nanoclusters and finally into two-dimensional (2D) domains, in which each CuPc molecule exhibits an apparent chiral feature. Such chiral features of the CuPc molecules can be attributed to the combined effect of asymmetric charge transfer between the CuPc and Bi(111) substrate, and the intermolecular van der Waals interactions.

In situ crystallization for fabrication of a core-satellite structured BiOBr-CdS heterostructure with excellent visible-light-responsive photoreactivity.

Science.gov (United States)

Guo, Yuxi; Huang, Hongwei; He, Ying; Tian, Na; Zhang, Tierui; Chu, Paul K; An, Qi; Zhang, Yihe

2015-07-21

We demonstrate the fabrication of a core-satellite structured BiOBr-CdS photocatalyst with highly efficient photocatalytic reactivity via a facile in situ crystallization approach at room temperature. The transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HR-TEM) results reveal that the BiOBr flakes are surrounded by CdS particles. The coverage of the satellites on the surface of the BiOBr nanosheets could be controlled by changing the content of the CdS, which contributes to the enhanced level of photocatalytic performance. The UV-vis diffuse reflection spectra demonstrate that the visible light absorption of the BiOBr-CdS photocatalyst is also enhanced by the CdS loaded. The excellent structural and spectral properties endow the BiOBr-CdS heterojunctions with improved photocatalytic performance pertaining to bisphenol A (BPA) degradation and photocurrent generation. Under visible light irradiation, the optimum photocatalytic activity of BiOBr-CdS at a molar ratio of 1 : 5 (CdS/BiOBr) is almost 2.8 times and 24.6 times as high as that of pure BiOBr and CdS. The remarkably enhanced photoreactivity should be attributed to the match in the energy levels and close core-satellite structural coupling between the CdS and BiOBr, which greatly facilitates the separation and transfer of photoinduced electron-hole pairs, as confirmed by photoluminescence (PL) and electrochemical impedance spectra (EIS). The present work sheds new light on the construction of highly efficient core-satellite heterojunctional photocatalysts for practical applications.

Thermoelectric properties and thermal stability of Bi-doped PbTe single crystal

Science.gov (United States)

Chen, Zhong; Li, Decong; Deng, Shuping; Tang, Yu; Sun, Luqi; Liu, Wenting; Shen, Lanxian; Yang, Peizhi; Deng, Shukang

2018-06-01

In this study, n-type Bi-doped single-crystal PbTe thermoelectric materials were prepared by melting and slow cooling method according to the stoichiometric ratio of Pb:Bi:Te = 1-x:x:1 (x = 0, 0.1, 0.15, 0.2, 0.25). The X-ray diffraction patterns of Pb1-xBixTe samples show that all main diffraction peaks are well matched with the PbTe matrix, which has a face-centered cubic structure with the space group Fm 3 bar m . Electron probe microanalysis reveals that Pb content decreases gradually, and Te content remains invariant basically with the increase of Bi content, indicating that Bi atoms are more likely to replace Pb atoms. Thermal analysis shows that the prepared samples possess relatively high thermal stability. Simultaneously, transmission electron microscopy and selected area electron diffraction pattern indicate that the prepared samples have typical single-crystal structures with good mechanical properties. Moreover, the electrical conductivity of the prepared samples improved significantly compared with that of the pure sample, and the maximum ZT value of 0.84 was obtained at 600 K by the sample with x = 0.2.

A Max-Flow Based Algorithm for Connected Target Coverage with Probabilistic Sensors

Directory of Open Access Journals (Sweden)

Anxing Shan

2017-05-01

Full Text Available Coverage is a fundamental issue in the research field of wireless sensor networks (WSNs. Connected target coverage discusses the sensor placement to guarantee the needs of both coverage and connectivity. Existing works largely leverage on the Boolean disk model, which is only a coarse approximation to the practical sensing model. In this paper, we focus on the connected target coverage issue based on the probabilistic sensing model, which can characterize the quality of coverage more accurately. In the probabilistic sensing model, sensors are only be able to detect a target with certain probability. We study the collaborative detection probability of target under multiple sensors. Armed with the analysis of collaborative detection probability, we further formulate the minimum ϵ-connected target coverage problem, aiming to minimize the number of sensors satisfying the requirements of both coverage and connectivity. We map it into a flow graph and present an approximation algorithm called the minimum vertices maximum flow algorithm (MVMFA with provable time complex and approximation ratios. To evaluate our design, we analyze the performance of MVMFA theoretically and also conduct extensive simulation studies to demonstrate the effectiveness of our proposed algorithm.

Modelling the implications of moving towards universal coverage in Tanzania.

Science.gov (United States)

Borghi, Josephine; Mtei, Gemini; Ally, Mariam

2012-03-01

A model was developed to assess the impact of possible moves towards universal coverage in Tanzania over a 15-year time frame. Three scenarios were considered: maintaining the current situation ('the status quo'); expanded health insurance coverage (the estimated maximum achievable coverage in the absence of premium subsidies, coverage restricted to those who can pay); universal coverage to all (government revenues used to pay the premiums for the poor). The model estimated the costs of delivering public health services and all health services to the population as a proportion of Gross Domestic Product (GDP), and forecast revenue from user fees and insurance premiums. Under the status quo, financial protection is provided to 10% of the population through health insurance schemes, with the remaining population benefiting from subsidized user charges in public facilities. Seventy-six per cent of the population would benefit from financial protection through health insurance under the expanded coverage scenario, and 100% of the population would receive such protection through a mix of insurance cover and government funding under the universal coverage scenario. The expanded and universal coverage scenarios have a significant effect on utilization levels, especially for public outpatient care. Universal coverage would require an initial doubling in the proportion of GDP going to the public health system. Government health expenditure would increase to 18% of total government expenditure. The results are sensitive to the cost of health system strengthening, the level of real GDP growth, provider reimbursement rates and administrative costs. Promoting greater cross-subsidization between insurance schemes would provide sufficient resources to finance universal coverage. Alternately, greater tax funding for health could be generated through an increase in the rate of Value-Added Tax (VAT) or expanding the income tax base. The feasibility and sustainability of efforts to

Inter-Layer Energy Transfer through Wetting-Layer States in Bi-layer InGaAs/GaAs Quantum-Dot Structures with Thick Barriers

DEFF Research Database (Denmark)

Xu, Zhang-Cheng; Zhang, Ya-Ting; Hvam, Jørn Märcher

2009-01-01

The inter-layer energy transfer in a bi-layer InGaAs/GaAs quantum dot structure with a thick GaAs barrier is studied using temperature-dependent photoluminescence. The abnormal enhancement of the photoluminescence of the QDs in the layer with a larger amount of coverage at 110K is observed, which...

Development of MnBi permanent magnet: Neutron diffraction of MnBi powder

Energy Technology Data Exchange (ETDEWEB)

Cui, J., E-mail: jun.cui@pnnl.gov; Choi, J. P.; Li, G.; Polikarpov, E.; Darsell, J. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354 (United States); Kramer, M. J.; Zarkevich, N. A.; Wang, L. L.; Johnson, D. D. [Materials Sciences and Engineering Division, Ames Laboratory, Ames, Iowa 50011 (United States); Marinescu, M. [Electron Energy Corporation, Landisville, Pennsylvania 17538 (United States); Huang, Q. Z.; Wu, H. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102 (United States); Vuong, N. V.; Liu, J. P. [Department of Physics, University of Texas at Arlington, Arlington, Texas 76019 (United States)

2014-05-07

MnBi attracts great attention in recent years for its great potential as permanent magnet materials. MnBi phase is difficult to obtain because of the rather drastic peritectic reaction between Mn and Bi. In this paper, we report our effort on synthesizing high purity MnBi compound using conventional powder metallurgical approaches. Neutron diffraction was carried out to investigate the crystal and nuclear structure of the obtained powder. The result shows that the purity of the obtained powder is about 91 wt. % at 300 K, and the magnetic moment of the Mn atom in MnBi lattice is 4.424 and 4.013 μ{sub B} at 50 K and 300 K, respectively.

Development of MnBi permanent magnet: Neutron diffraction of MnBi powder

Energy Technology Data Exchange (ETDEWEB)

Cui, J; Choi, JP; Li, G; Polikarpov, E; Darsell, J; Kramer, MJ; Zarkevich, NA; Wang, LL; Johnson, DD; Marinescu, M; Huang, QZ; Wu, H; Vuong, NV; Liu, JP

2014-05-07

MnBi attracts great attention in recent years for its great potential as permanent magnet materials. MnBi phase is difficult to obtain because of the rather drastic peritectic reaction between Mn and Bi. In this paper, we report our effort on synthesizing high purity MnBi compound using conventional powder metallurgical approaches. Neutron diffraction was carried out to investigate the crystal and nuclear structure of the obtained powder. The result shows that the purity of the obtained powder is about 91 wt. % at 300 K, and the magnetic moment of the Mn atom in MnBi lattice is 4.424 and 4.013 mu(B) at 50 K and 300 K, respectively. (C) 2014 AIP Publishing LLC.

Synthesis of Volumetric Ring Antenna Array for Terrestrial Coverage Pattern

Directory of Open Access Journals (Sweden)

Alberto Reyna

2014-01-01

Full Text Available This paper presents a synthesis of a volumetric ring antenna array for a terrestrial coverage pattern. This synthesis regards the spacing among the rings on the planes X-Y, the positions of the rings on the plane X-Z, and uniform and concentric excitations. The optimization is carried out by implementing the particle swarm optimization. The synthesis is compared with previous designs by resulting with proper performance of this geometry to provide an accurate coverage to be applied in satellite applications with a maximum reduction of the antenna hardware as well as the side lobe level reduction.

Synthesis of Volumetric Ring Antenna Array for Terrestrial Coverage Pattern

Science.gov (United States)

Reyna, Alberto; Panduro, Marco A.; Del Rio Bocio, Carlos

2014-01-01

This paper presents a synthesis of a volumetric ring antenna array for a terrestrial coverage pattern. This synthesis regards the spacing among the rings on the planes X-Y, the positions of the rings on the plane X-Z, and uniform and concentric excitations. The optimization is carried out by implementing the particle swarm optimization. The synthesis is compared with previous designs by resulting with proper performance of this geometry to provide an accurate coverage to be applied in satellite applications with a maximum reduction of the antenna hardware as well as the side lobe level reduction. PMID:24701150

Use of a preconditioned Bi-conjugate gradient method for hybrid plasma stability analysis

International Nuclear Information System (INIS)

Mikic, Z.; Morse, E.C.

1985-01-01

The numerical stability analysis of compact toroidal plasmas using implicit time differencing requires the solution of a set of coupled, 2-dimensional, elliptic partial differential equations for the field quantities at every timestep. When the equations are spatially finite-differenced and written in matrix form, the resulting matrix is large, sparse, complex, non-Hermitian, and indefinite. The use of the preconditioned bi-conjugate gradient method for solving these equations is discussed. The effect of block-diagonal preconditioning and incomplete block-LU preconditionig on the convergence of the method is investigated. For typical matrices arising in our studies, the eigenvalue spectra of the original and preconditioned matrices are calculated as an illustration of the effectiveness of the preconditioning. We show that the preconditioned bi-conjugate gradient method coverages more rapidly than the conjugate gradient method applied to the normal equations, and that it is an effective iterative method for the class of non-Hermitian, indefinite problems of interest

Global EiBI-monopole

Directory of Open Access Journals (Sweden)

JIN Xinghua

2014-04-01

Full Text Available A global EiBI-monopole problem is studied under EiBI gravitational theory.The equations of global EiBI-monopole are derived in the curved spacetime and the relation between the spacetime metric and auxiliary metric is found.In the case of a very small parameter,an asymptotic form of equations is given.The series solutions of global EiBI-monopole at infinity are found.

Tunable blue–violet Cr3+:LiCAF + BiBO compact laser

International Nuclear Information System (INIS)

Maestre, H; Torregrosa, A J; Capmany, J

2015-01-01

We present a compact continuous wave (CW) external-cavity tunable Cr 3+ :LiCaAlF 6 (Cr:LiCAF) laser which is intracavity frequency doubled using a BiB 3 O 6 (BiBO) nonlinear crystal to obtain tunable blue–violet radiation. The generated second harmonic (SH) can be tuned by means of either angular or temperature variation of the nonlinear crystal. We have obtained SH radiation between 390–415 nm and a maximum output power of 34 mW at 400 nm. Future improvements on the SH tuning range and output power are addressed in the text. Our results may be applied in the design of compact tunable composite external-cavity solid-state lasers. (paper)

78 FR 691 - Maximum Loan Amount for Business and Industry Guaranteed Loans in Fiscal Year 2013

Science.gov (United States)

2013-01-04

... DEPARTMENT OF AGRICULTURE Rural Business-Cooperative Service Maximum Loan Amount for Business and Industry Guaranteed Loans in Fiscal Year 2013 AGENCY: Rural Business-Cooperative Service, USDA. ACTION... and Industry (B&I) guaranteed loans of $25 million or less under certain circumstances. Due to the...

Novel ultrathin Bi2O3 nanowires for supercapacitor electrode materials with high performance

Science.gov (United States)

Qiu, Yongfu; Fan, Hongbo; Chang, Xueyi; Dang, Haifeng; Luo, Qun; Cheng, Zhiyu

2018-03-01

In this paper, the ultrathin Bi2O3 nanowires are synthesized by an oxidative metal vapor transport deposition technique. Their diameters and length are about 10 nm and several tens of micrometers, the growth direction is along [101] and the specific surface area is about 7.34 m2 g-1. The galvanostatic charge-discharge measurement results show that the specific capacitances of the Bi2O3 nanowires-based electrodes increase with the decrease of the current densities. The maximum capacitance is 691.3 F g-1 at the current density of 2.0 A g-1. The Ragone plot shows that the Bi2O3 nanowires has excellent supercapacitive performance. Moreover, the cyclic stability is measured by the galvanostatic charge/discharge technique at a constant current density of 10.0 A g-1 in 6.0 M KOH electrolyte. The results show the excellent capacitance retention of 75.5% over 3000 cycles. In a word, the Bi2O3 nanowires should be the ideal potential electrode materials for low-costing and effective electrochemical supercapacitors.

Positron-annihilation studies on the Bi-Sr-Ca-Cu-O superconductor

International Nuclear Information System (INIS)

Sundar, C.S.; Bharathi, A.; Ching, W.Y.; Jean, Y.C.; Hor, P.H.; Meng, R.L.; Huang, Z.J.; Chu, C.W.

1991-01-01

The results of positron-lifetime measurements as a function of temperature, across T c , and as a function of heat treatment are presented. The lifetime in Bi-Sr-Ca-Cu-O does not show any variation with temperature in the range of 10 to 300 K, a result that is in contrast with other cuprate superconductors. The absence of lifetime variation across T c is understood in terms of the calculated positron-density distribution, which indicates that the maximum of the positron density is in the region between the Bi-O layers with no significant density in the superconducting CuO 2 layers. Positron-lifetime measurements as a function of heat treatment indicate a decrease in lifetime as the annealing temperature is lowered from 800 degree C to 100 degree C. The decrease in lifetime, which is correlated with the increase in the weight of the sample, is explained in terms of the intercalation of the excess oxygen in the region between the Bi-O layers, which is the region probed by the positron

Tolerance of topological surface state towards adsorbed magnetic moments: Fe on Bi{sub 2}Te{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Scholz, Markus; Marchenko, Dmitry; Sanchez-Barriga, Jaime; Varykhalov, Andrei; Rader, Oliver [Helmholtz-Zentrum fuer Materialien und Energie, Berlin (Germany); Volykhov, Andrei; Yashina, Lada [Moscow State University, Moskau, Russland (Russian Federation)

2011-07-01

Topological surface states on Bi{sub 2}Se{sub 3} and Bi{sub 2}Te{sub 3} are protected by time reversal symmetry. Magnetic fields break time-reversal symmetry, and they have been used in two-dimensional spin quantum-Hall systems to destroy the topological edge states. Another possibility is to introduce magnetic moments. This has been done by substitution of Mn and Fe into the bulk. For Fe a small gap of 44meV was created, however, at very large amounts (12%). In this work, we deposit Fe directly onto the surface where the topological surface state is localized. We show for coverages of 0.25 and 1 ML Fe that the Dirac point remains intact and no gap appears. Core level spectroscopy of Bi and Te states gives insight into the interaction between substrate and adatoms. In addition, extra surface states appear at the Fermi energy which show a large Rashba-type spin-orbit splitting. The orientation of the spin of both, the topological as well as the Rashba-type split surface states is analysed.

Effective visible light-active nitrogen and samarium co-doped BiVO4 for the degradation of organic pollutants

International Nuclear Information System (INIS)

Wang, Min; Niu, Chao; Liu, Jun; Wang, Qianwu; Yang, Changxiu; Zheng, Haoyan

2015-01-01

Nitrogen and samarium co-doped BiVO 4 (N–xSm–BiVO 4 ) nanoparticles were synthesized using a sol–gel method with a corn stem template. The physicochemical properties of the resultant N–xSm–BiVO 4 particles were characterized using various methods: XPS, XRD, SEM, BET, and UV–Vis DRS analyses. The visible-light photocatalytic activity was successfully demonstrated by degrading a model dye, namely, methyl orange. The dopant content was optimized, and the nitrogen and samarium co-doped BiVO 4 extended the light absorption spectrum toward the visible region, significantly enhancing the photodegradation of the model dye. The Sm and N co-doped BiVO 4 exhibited the highest photocatalytic activity compared to materials with a single dopant or no dopant. The significantly enhanced photocatalytic activity of the N–Sm co-doped BiVO 4 under visible-light irradiation can be attributed to the synergistic effects of the nitrogen and samarium. - Highlights: • The N–Sm codoped BiVO 4 were synthesized using a sol–gel method with a corn stem template. • The N and Sm codoped BiVO 4 has excellent photocatalytic activity of methyl orange degradation. • The maximum activity was observed when the molar ratio of Sm/Bi was 1.0. • The high photocatalytic activity was caused by the synergistic effects between N doping and Sm doping

High photocatalytic performance of BiOI/Bi{sub 2}WO{sub 6} toward toluene and Reactive Brilliant Red

Energy Technology Data Exchange (ETDEWEB)

Li Huiquan [School of Chemistry and Chemical Engineering, Fuyang Normal College, Fuyang 236041 (China); Key Laboratory of Mesoscopic Chemistry of MOE, Jiangsu Provincial Key Laboratory of Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Cui Yumin, E-mail: cuiyumin0908@163.com [School of Chemistry and Chemical Engineering, Fuyang Normal College, Fuyang 236041 (China); Hong Wenshan [School of Chemistry and Chemical Engineering, Fuyang Normal College, Fuyang 236041 (China)

2013-01-01

Graphical abstract: When BiOI/Bi{sub 2}WO{sub 6} catalyst was exposed to UV or visible light, the electrons in the valence band of Bi{sub 2}WO{sub 6} would be excited into the conduction band and then injected into the more positive conduction band of BiOI. Therefore, the photoelectrons were generated from Bi{sub 2}WO{sub 6} and transferred across the interface between BiOI and Bi{sub 2}WO{sub 6} to the surface of BiOI, leaving the photogenerated holes in the valence band of Bi{sub 2}WO{sub 6}. In this way, the photoinduced electron-hole pairs were effectively separated. Highlights: Black-Right-Pointing-Pointer BiOI sensitized Bi{sub 2}WO{sub 6} catalysts were successfully prepared by a facile method. Black-Right-Pointing-Pointer The 13.2% BiOI/Bi{sub 2}WO{sub 6} catalyst exhibits higher photoactivities than P25. Black-Right-Pointing-Pointer A possible transfer process of photogenerated carriers was proposed. - Abstract: BiOI sensitized nano-Bi{sub 2}WO{sub 6} photocatalysts with different BiOI contents were successfully synthesized by a facile deposition method at room temperature, and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) high-resolution transmission electron microscopy (HR-TEM), photoluminescence (PL) spectra, UV-vis diffuse reflection spectroscopy (UV-vis DRS) and Brunauer-Emmett-Teller (BET) surface area measurements. The photocatalytic activity of BiOI/Bi{sub 2}WO{sub 6} was evaluated by the photo-degradation of Reactive Brilliant Red (X-3B) in suspended solution and toluene in gas phase. It has been shown that the BiOI/Bi{sub 2}WO{sub 6} catalysts exhibit a coexistence of both tetragonal BiOI and orthorhombic Bi{sub 2}WO{sub 6} phases. With increasing BiOI content, the absorption intensity of BiOI/Bi{sub 2}WO{sub 6} catalysts increases in the 380-600 nm region and the absorption edge shifts significantly to longer wavelengths as compared to pure Bi{sub 2}WO{sub 6}. The 13.2% BiOI/Bi{sub 2}WO{sub 6} catalyst exhibits

MLED_BI: a new BI Design Approach to Support Multilingualism in Business Intelligence

Directory of Open Access Journals (Sweden)

Nedim Dedić

2017-11-01

Full Text Available Existing approaches to support Multilingualism (ML in Business Intelligence (BI create problems for business users, present a number of challenges from the technical perspective, and lead to issues with logical dependence in the star schema. In this paper, we propose MLED_BI (Multilingual Enabled Design for Business Intelligence, a novel BI design approach to support the application of ML in BI Environment, which overcomes the issues and problems found with existing approaches. The approach is based on a revision of the data warehouse dimensional modelling approach and treats the Star Schema as a higher level entity. This paper describes MLED_BI and the validation and evaluation approach used.

Ga-Bi-Te system

International Nuclear Information System (INIS)

Rustamov, P.G.; Seidova, N.A.; Shakhbazov, M.G.; AN Azerbajdzhanskoj SSR, Baku. Inst. Neorganicheskoj i Fizicheskoj Khimii)

1976-01-01

To elucidate the nature of interaction in the system Ga-Bi-Te, a study has been made of sections GaTe-Bi 2 Te 3 , Ga 2 Te 3 -Bi, GaTe-Bi and Bi 2 Te 3 -Ga. The alloys have been prepared by direct melting of the components or their alloys with subsequent homogenizin.o annealing at 400 deg C. The study has been made by the methods of differential thermal, microstructural analysis and by microhardness measurements. On the basis of literature data and data obtained a projection of the liquidus surface of the phase diagram for the system Ga-Bi-Te has been constructed. In the ternary system there are 17 curves of monovariant equilibrium dividing the liquidus into 10 fields of primary crystallization of phases, 9 points of non-variant equilibrium of which 4 points are triple eutectics and 5 points are triple peritectics

Electronic structures and stability of Ni/Bi2Te3 and Co/Bi2Te3 interfaces

International Nuclear Information System (INIS)

Xiong Ka; Wang Weichao; Alshareef, Husam N; Gupta, Rahul P; Gnade, Bruce E; Cho, Kyeongjae; White, John B

2010-01-01

We investigate the electronic structures and stability for Ni/Bi 2 Te 3 , NiTe/Bi 2 Te 3 , Co/Bi 2 Te 3 and CoTe 2 /Bi 2 Te 3 interfaces by first-principles calculations. It is found that the surface termination strongly affects the band alignment. Ni and Co are found to form Ohmic contacts to Bi 2 Te 3 . The interface formation energy for Co/Bi 2 Te 3 interfaces is much lower than that of Ni/Bi 2 Te 3 interfaces. Furthermore, we found that NiTe on Bi 2 Te 3 is more stable than Ni, while the formation energies for Co and CoTe 2 on Bi 2 Te 3 are comparable.

Developments of high strength Bi-containing Sn0.7Cu lead-free solder alloys prepared by directional solidification

Energy Technology Data Exchange (ETDEWEB)

Hu, Xiaowu, E-mail: xwhmaterials@aliyun.com [School of Mechanical Electrical Engineering, Nanchang University, Nanchang 330031 (China); Li, Yulong [School of Mechanical Electrical Engineering, Nanchang University, Nanchang 330031 (China); Liu, Yi [School of Materials Science and Engineering, Nanchang University, Nanchang 330031 (China); Min, Zhixian [China Electronics Technology Group Corporation No. 38 Research Institute, Hefei 230088 (China)

2015-03-15

Highlights: • The Sn0.7Cu–xBi solder alloys were directionally solidified. • Both spacing and diameter of fibers decreased with increasing solidification rate. • The UTS and YS first increased with increased solidification rate, then decreased. • The UTS and YS of Sn0.7Cu–xBi first increased with increased Bi content. - Abstract: Bi-containing Sn0.7Cu (SC) eutectic solder alloys were prepared and subjected to directional solidification, through which new types of fiber reinforced eutectic composites were generated. The influences of Bi addition on the microstructures and tensile properties of directionally solidified (DS) Bi-containing eutectic SC lead-free solder alloys have been investigated by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and a tensile testing machine. The experimental results showed that addition of Bi could effectively reduce both the melting temperature and undercooling of SC solder alloy. The microstructures of DS SC–xBi solder alloys were composed of Sn-rich phase (β) and Cu{sub 6}Sn{sub 5} fiber. No other intermetallic compounds (IMCs) with Bi content were observed in the solder matrix for SC solder alloys with various Bi contents. Both fiber spacing and diameter all decreased gradually with increasing growth rate and/or Bi content. Besides, the regularity of Cu{sub 6}Sn{sub 5} fibers alignment also decreased with increasing growth rate, too. The tensile strengths of the SC–xBi eutectic solder alloys varied parabolically with growth rate (R). When R was 60 μm/s, maximum tensile strengths of 43.8, 55.2 and 56.37 MPa were reached for SC, SC0.7Bi and SC1.3Bi solder alloys. A comparison of tensile strength of SC, SC0.7Bi and SC1.3Bi with the same R indicated that the tensile strength increased with increasing Bi content, which was attributed to the presence of Bi and its role in refining microstructure and solid solution strengthening.

Electronic structures and stability of Ni/Bi2Te3 and Co/Bi2Te3 interfaces

KAUST Repository

Xiong, Ka; Wang, Weichao; Alshareef, Husam N.; Gupta, Rahul P.; White, John B.; Gnade, Bruce E.; Cho, Kyeongjae

2010-01-01

We investigate the electronic structures and stability for Ni/Bi 2Te3, NiTe/Bi2Te3, Co/Bi 2Te3 and CoTe2/Bi2Te3 interfaces by first-principles calculations. It is found that the surface termination strongly affects the band alignment. Ni and Co are found to form Ohmic contacts to Bi2Te3. The interface formation energy for Co/Bi2Te3 interfaces is much lower than that of Ni/Bi2Te3 interfaces. Furthermore, we found that NiTe on Bi2Te3 is more stable than Ni, while the formation energies for Co and CoTe2 on Bi2Te3 are comparable. © 2010 IOP Publishing Ltd.

Electronic structures and stability of Ni/Bi2Te3 and Co/Bi2Te3 interfaces

KAUST Repository

Xiong, Ka

2010-03-04

We investigate the electronic structures and stability for Ni/Bi 2Te3, NiTe/Bi2Te3, Co/Bi 2Te3 and CoTe2/Bi2Te3 interfaces by first-principles calculations. It is found that the surface termination strongly affects the band alignment. Ni and Co are found to form Ohmic contacts to Bi2Te3. The interface formation energy for Co/Bi2Te3 interfaces is much lower than that of Ni/Bi2Te3 interfaces. Furthermore, we found that NiTe on Bi2Te3 is more stable than Ni, while the formation energies for Co and CoTe2 on Bi2Te3 are comparable. © 2010 IOP Publishing Ltd.

Bismuth-boron multiple bonding in BiB{sub 2}O{sup -} and Bi{sub 2}B{sup -}

Energy Technology Data Exchange (ETDEWEB)

Jian, Tian; Cheung, Ling Fung; Chen, Teng-Teng; Wang, Lai-Sheng [Department of Chemistry, Brown University, Providence, RI (United States)

2017-08-01

Despite its electron deficiency, boron is versatile in forming multiple bonds. Transition-metal-boron double bonding is known, but boron-metal triple bonds have been elusive. Two bismuth boron cluster anions, BiB{sub 2}O{sup -} and Bi{sub 2}B{sup -}, containing triple and double B-Bi bonds are presented. The BiB{sub 2}O{sup -} and Bi{sub 2}B{sup -} clusters are produced by laser vaporization of a mixed B/Bi target and characterized by photoelectron spectroscopy and ab initio calculations. Well-resolved photoelectron spectra are obtained and interpreted with the help of ab initio calculations, which show that both species are linear. Chemical bonding analyses reveal that Bi forms triple and double bonds with boron in BiB{sub 2}O{sup -} ([Bi≡B-B≡O]{sup -}) and Bi{sub 2}B{sup -} ([Bi=B=Bi]{sup -}), respectively. The Bi-B double and triple bond strengths are calculated to be 3.21 and 4.70 eV, respectively. This is the first experimental observation of Bi-B double and triple bonds, opening the door to design main-group metal-boron complexes with multiple bonding. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Microstructure Of MnBi/Bi Eutectic Alloy

Science.gov (United States)

Wilcox, William R.; Eisa, G. F.; Baskaran, B.; Richardson, Donald C.

1988-01-01

Collection of three reports describes studies of directional solidification of MnBi/Bi eutectic alloy. Two of the reports, "Influence of Convection on Lamellar Spacing of Eutectics" and "Influence of Convection on Eutectic Microstructure," establish theoretical foundation for remaining document. Reports seek to quantify effect of convection on concentration field of growing lamellar eutectic. Remaining report, "Study of Eutectic Formation," begins by continuing theoretical developments. New technique under development by one of the authors helps to reveal three-dimensional microstructures of alloys.

Photocatalytic activity of Bi{sub 2}WO{sub 6}/Bi{sub 2}S{sub 3} heterojunctions: the facilitation of exposed facets of Bi{sub 2}WO{sub 6} substrate

Energy Technology Data Exchange (ETDEWEB)

Yan, Long [School of Chemistry and Chemical Engineering, Yulin University, Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization, Yulin 71900 (China); School of Chemistry and Chemical Engineering, Yan’an University, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan’an 716000 (China); Wang, Yufei [School of Chemistry and Chemical Engineering, Yulin University, Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization, Yulin 71900 (China); Shen, Huidong; Zhang, Yu [School of Chemistry and Chemical Engineering, Yan’an University, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan’an 716000 (China); Li, Jian [School of Chemistry and Chemical Engineering, Yulin University, Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization, Yulin 71900 (China); Wang, Danjun, E-mail: yulyanlong@aliyun.com [School of Chemistry and Chemical Engineering, Yan’an University, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan’an 716000 (China)

2017-01-30

Highlights: • Bi{sub 2}S{sub 3}/Bi{sub 2}WO{sub 6} hybrids with exposed (020) Bi{sub 2}WO{sub 6} facets have been synthesized. • X-ray photoelectron spectroscopy reveals that a small amount of Bi{sub 2}S{sub 3} was formed. • The enhanced photoactivity of hybrids is due to heterojunction and (020) facets. • A possible photocatalytic degradation mechanism is proposed. - Abstract: Bi{sub 2}S{sub 3}/Bi{sub 2}WO{sub 6} hybrid architectures with exposed (020) Bi{sub 2}WO{sub 6} facets have been synthesized via a controlled anion exchange approach. X-ray photoelectron spectroscopy (XPS) reveals that a small amount of Bi{sub 2}S{sub 3} was formed on the surface of Bi{sub 2}WO{sub 6} during the anion exchange process, thus leading to the transformation from the Bi{sub 2}WO{sub 6} to Bi{sub 2}S{sub 3}/Bi{sub 2}WO{sub 6}. A rhodamine B (RhB) aqueous solution was chosen as model organic pollutants to evaluate the photocatalytic activities of the Bi{sub 2}S{sub 3}/Bi{sub 2}WO{sub 6} catalysts. Under visible light irradiation, the Bi{sub 2}S{sub 3}/Bi{sub 2}WO{sub 6}-TAA displayed the excellent visible light photoactivities compared with pure Bi{sub 2}S{sub 3}, Bi{sub 2}WO{sub 6} and other composite photocatalysts. The efficient photocatalytic activity of the Bi{sub 2}S{sub 3}/Bi{sub 2}WO{sub 6}-TAA composite microspheres was ascribed to the constructed heterojunctions and the inner electric field caused by the exposed (020) Bi{sub 2}WO{sub 6} facets. Active species trapping experiments revealed that h{sup +} and O{sub 2}·{sup −} are the main active species in the photocatalytic process. Furthermore, the as-obtained photocatalysts showed good photocatalytic activity after four recycles. The results presented in this study provide a new concept for the rational design and development of highly efficient photocatalysts.

Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO3 thin film

International Nuclear Information System (INIS)

Gupta, Surbhi; Gupta, Vinay; Tomar, Monika; James, A. R.; Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar

2014-01-01

Multiferroic Bismuth Ferrite (BiFeO 3 ) thin films with varying excess bismuth (Bi) concentration were grown by chemical solution deposition technique. Room temperature multiferroic properties (ferromagnetism, ferroelectricity, and piezoelectricity) of the deposited BiFeO 3 thin films have been studied. High resolution X-ray diffraction and Raman spectroscopy studies reveal that the dominant phases formed in the prepared samples change continuously from a mixture of BiFeO 3 and Fe 2 O 3 to pure BiFeO 3 phase and, subsequently, to a mixture of BiFeO 3 and Bi 2 O 3 with increase in the concentration of excess Bi from 0% to 15%. BiFeO 3 thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (γ-Fe 2 O 3 ). Deterioration in ferroic properties of BiFeO 3 thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO 3 thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 μC/cm 2 and saturation magnetization 11.66 emu/g. The switching of fine spontaneous domains with applied dc bias has been observed using piezoresponse force microscopy in BiFeO 3 thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO 3 thin films exhibiting the improved multiferroic properties.

A model of knock-out of oxygen by charged particle irradiation of Bi-2212

International Nuclear Information System (INIS)

Bandyopadhyay, S.K.; Sen, Pintu; Barat, P.; Mukherjee, P.; Das, S.K.; Ghosh, B.

1996-01-01

A model of knock-out of oxygen by charged particle (α and proton) irradiation of Bi 2 Sr 2 CaCu 2 O 8+x (Bi-2212) is proposed on the basis of Monte Carlo TRIM calculations. In Bi-2212, the loosely bound excess oxygen is vulnerable to be displaced by particle irradiation. Binding energy and hence, displacement energy of this loosely bound excess oxygen is less compared to that of stoichiometric lattice bound oxygen and other atoms. The displaced or knocked out oxygen goes to pores or intergranular region and generates large pressure inside the sample. Because of porosity of the material, this displaced oxygen diffuses out and there is a net reduction of oxygen content of the sample. The irradiation induced oxygen knock-out is dominant in the bulk where nonionizing energy loss is maximum. (author). 29 refs., 1 fig., 3 tabs

OXIDACIÓN ELECTROQUÍMICA DE LAMBDACIALOTRINA SOBRE ELECTRODOS DE PBO2-BI

Directory of Open Access Journals (Sweden)

Leonardo Cifuentes

2015-09-01

Full Text Available The electrochemical oxidation of lambdacyhalotrin in a triton X-100 water solution on a PbO2-Bi electrode has been studied. It was discovered that electrocatalytic degradation proceeded through the Langmuir-Hinshelwood (L-H mechanism. The Langmuir adsorption equilibrium constant of the organic compound on the PbO2-Bi surface (0.67 (±0.02 mg-1L and the L-H maximum reaction rate for lambdacyhalotrin oxidation (0.040 (±0.002 mg L-1 min-1 was also determined on the basis of kinetic data. Oxidation/mineralization was tested at electrode potential higher than 2.3 V vs. Ag/AgCl, in this conditions the higher degradation percent of 85 (±4 % has been obtained.

Topotactic synthesis of a new BiS2-based superconductor Bi2(O,F)S2

OpenAIRE

Okada, Tomoyuki; Ogino, Hiraku; Shimoyama, Jun-ichi; Kishio, Kohji

2015-01-01

A new BiS2-based superconductor Bi2(O,F)S2 was discovered. This is a layered compound consisting of alternate stacking structure of rock-salt-type BiS2 superconducting layer and fluorite-type Bi(O,F) blocking layer. Bi2(O,F)S2 was obtained as the main phase by topotactic fluorination of undoped Bi2OS2 using XeF2, which is the first topotactic synthesis of an electron-doped superconductor via reductive fluorination. With increasing F-content, a- and c-axis length increased and decreased, respe...

One step synthesis of Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon spheres with enhanced photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Qu, Lingling [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Luo, Zhijun, E-mail: lzj@ujs.edu.cn [School of the Environment, Jiangsu University, Zhenjiang 212013 (China); State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093 (China); Tang, Chao [Maple Leaf International High School, Zhenjiang 212013 (China)

2013-11-15

Graphical abstract: Functional groups of sodium gluconate play synergetic roles in the formation of Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon core–shell nanosturctures (Bi@Bi{sub 2}O{sub 3}@CRCSs). Bi@Bi{sub 2}O{sub 3}@CRCSs exhibits significant enhanced photocatalytic activity under visible light irradiation. - Highlights: • One step synthesis of Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon spheres. • Functional groups of sodium gluconate play synergetic roles in the formation of Bi@Bi{sub 2}O{sub 3}@CRCSs. • Bi@Bi{sub 2}O{sub 3}@CRCSs exhibits enhanced photocatalytic activity under visible light irradiation. - Abstract: Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon core-shell nanosturctures (Bi@Bi{sub 2}O{sub 3}@CRCSs) have been synthesized via a one-step method. The core–shell nanosturctures of the as-prepared samples were confirmed by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Raman spectroscopy. The formation of Bi@Bi{sub 2}O{sub 3}@CRCSs core–shell nanosturctures should attribute to the synergetic roles of different functional groups of sodium gluconate. Bi@Bi{sub 2}O{sub 3}@CRCSs exhibits significant enhanced photocatalytic activity under visible light irradiation (λ > 420 nm) and shows an O{sub 2}-dependent feature. According to trapping experiments of radicals and holes, hydroxyl radicals were not the main active oxidative species in the photocatalytic degradation of MB, but O{sub 2}·{sup −} are the main active oxidative species.

An Advanced Semimetal-Organic Bi Spheres-g-C3N4 Nanohybrid with SPR-Enhanced Visible-Light Photocatalytic Performance for NO Purification.

Science.gov (United States)

Dong, Fan; Zhao, Zaiwang; Sun, Yanjuan; Zhang, Yuxin; Yan, Shuai; Wu, Zhongbiao

2015-10-20

To achieve efficient photocatalytic air purification, we constructed an advanced semimetal-organic Bi spheres-g-C3N4 nanohybrid through the in-situ growth of Bi nanospheres on g-C3N4 nanosheets. This Bi-g-C3N4 compound exhibited an exceptionally high and stable visible-light photocatalytic performance for NO removal due to the surface plasmon resonance (SPR) endowed by Bi metal. The SPR property of Bi could conspicuously enhance the visible-light harvesting and the charge separation. The electromagnetic field distribution of Bi spheres involving SPR effect was simulated and reaches its maximum in close proximity to the Bi particle surface. When the Bi metal content was controlled at 25%, the corresponding Bi-g-C3N4 displayed outstanding photocatalytic capability and transcended those of other visible-light photocatalysts. The Bi-g-C3N4 exhibited a high structural stability under repeated photocatalytic runs. A new visible-light-induced SPR-based photocatalysis mechanism with Bi-g-C3N4 was proposed on the basis of the DMPO-ESR spin-trapping. The photoinduced electrons could transfer from g-C3N4 to the Bi metal, as revealed with time-resolved fluorescence spectra. The function of Bi semimetal as a plasmonic cocatalyst for boosting visible light photocatalysis was similar to that of noble metals, which demonstrated a great potential of utilizing the economically feasible Bi element as a substitute for noble metals for the advancement of photocatalysis efficiency.

CT following US for possible appendicitis: anatomic coverage

Energy Technology Data Exchange (ETDEWEB)

O' Malley, Martin E. [University of Toronto, Princess Margaret Hospital, 3-920, Joint Department of Medical Imaging, Toronto, Ontario (Canada); Alharbi, Fawaz [University of Toronto, Toronto General Hospital, NCSB 1C572, Joint Department of Medical Imaging, Toronto, Ontario (Canada); Qassim University, Department of Medical Imaging, Buraydah, Qassim (Saudi Arabia); Chawla, Tanya P. [University of Toronto, Mount Sinai Hospital, Room 567, Joint Department of Medical Imaging, Toronto, Ontario (Canada); Moshonov, Hadas [University of Toronto, Joint Department of Medical Imaging, Toronto, Ontario (Canada)

2016-02-15

To determine superior-inferior anatomic borders for CT following inconclusive/nondiagnostic US for possible appendicitis. Ninety-nine patients with possible appendicitis and inconclusive/nondiagnostic US followed by CT were included in this retrospective study. Two radiologists reviewed CT images and determined superior-inferior anatomic borders required to diagnose or exclude appendicitis and diagnose alternative causes. This ''targeted'' coverage was used to estimate potential reduction in anatomic coverage compared to standard abdominal/pelvic CT. The study group included 83 women and 16 men; mean age 32 (median, 29; range 18-73) years. Final diagnoses were: nonspecific abdominal pain 50/99 (51 %), appendicitis 26/99 (26 %), gynaecological 12/99 (12 %), gastrointestinal 9/99 (10 %), and musculoskeletal 2/99 (2 %). Median dose-length product for standard CT was 890.0 (range, 306.3 - 2493.9) mGy.cm. To confidently diagnose/exclude appendicitis or identify alternative diagnoses, maximum superior-inferior anatomic CT coverage was the superior border of L2-superior border of pubic symphysis, for both reviewers. Targeted CT would reduce anatomic coverage by 30-55 % (mean 39 %, median 40 %) compared to standard CT. When CT is performed for appendicitis following inconclusive/nondiagnostic US, targeted CT from the superior border of L2-superior border of pubic symphysis can be used resulting in significant reduction in exposure to ionizing radiation compared to standard CT. (orig.)

CT following US for possible appendicitis: anatomic coverage

International Nuclear Information System (INIS)

O'Malley, Martin E.; Alharbi, Fawaz; Chawla, Tanya P.; Moshonov, Hadas

2016-01-01

To determine superior-inferior anatomic borders for CT following inconclusive/nondiagnostic US for possible appendicitis. Ninety-nine patients with possible appendicitis and inconclusive/nondiagnostic US followed by CT were included in this retrospective study. Two radiologists reviewed CT images and determined superior-inferior anatomic borders required to diagnose or exclude appendicitis and diagnose alternative causes. This ''targeted'' coverage was used to estimate potential reduction in anatomic coverage compared to standard abdominal/pelvic CT. The study group included 83 women and 16 men; mean age 32 (median, 29; range 18-73) years. Final diagnoses were: nonspecific abdominal pain 50/99 (51 %), appendicitis 26/99 (26 %), gynaecological 12/99 (12 %), gastrointestinal 9/99 (10 %), and musculoskeletal 2/99 (2 %). Median dose-length product for standard CT was 890.0 (range, 306.3 - 2493.9) mGy.cm. To confidently diagnose/exclude appendicitis or identify alternative diagnoses, maximum superior-inferior anatomic CT coverage was the superior border of L2-superior border of pubic symphysis, for both reviewers. Targeted CT would reduce anatomic coverage by 30-55 % (mean 39 %, median 40 %) compared to standard CT. When CT is performed for appendicitis following inconclusive/nondiagnostic US, targeted CT from the superior border of L2-superior border of pubic symphysis can be used resulting in significant reduction in exposure to ionizing radiation compared to standard CT. (orig.)

Topotactic synthesis of a new BiS2-based superconductor Bi2(O,F)S2

Science.gov (United States)

Okada, Tomoyuki; Ogino, Hiraku; Shimoyama, Jun-ichi; Kishio, Kohji

2015-02-01

A new BiS2-based superconductor, Bi2(O,F)S2, was discovered. It is a layered compound consisting of alternately stacked structure of rock-salt-type BiS2 superconducting layers and fluorite-type Bi(O,F) blocking layers. Bi2(O,F)S2 was obtained as the main phase by topotactic fluorination of undoped Bi2OS2 using XeF2. This is the first topotactic synthesis of an electron-doped superconductor via reductive fluorination. With increasing F-content, a- and c-axis lengths increased and decreased, respectively, and Tc increased to 5.1 K.

Sodium citrate-assisted anion exchange strategy for construction of Bi2O2CO3/BiOI photocatalysts

International Nuclear Information System (INIS)

Song, Peng-Yuan; Xu, Ming; Zhang, Wei-De

2015-01-01

Highlights: • Heterostructured Bi 2 O 2 CO 3 /BiOI microspheres were prepared via anion exchange. • Sodium citrate-assisted anion exchange for construction of composite photocatalysts. • Bi 2 O 2 CO 3 /BiOI composites show high visible light photocatalytic activity. - Abstract: Bi 2 O 2 CO 3 /BiOI heterojuncted photocatalysts were constructed through a facile partial anion exchange strategy starting from BiOI microspheres and urea with the assistance of sodium citrate. The content of Bi 2 O 2 CO 3 in the catalysts was regulated by modulating the amount of urea as a precursor, which was decomposed to generate CO 3 2− in the hydrothermal process. Citrate anion plays a key role in controlling the morphology and composition of the products. The Bi 2 O 2 CO 3 /BiOI catalysts display much higher photocatalytic activity than pure BiOI and Bi 2 O 2 CO 3 towards the degradation of rhodamine B (RhB) and bisphenol A (BPA). The enhancement of photocatalytic activity of the heterojuncted catalysts is attributed to the formation of p–n junction between p-BiOI and n-Bi 2 O 2 CO 3 , which is favorable for retarding the recombination of photoinduced electron-hole pairs. Moreover, the holes are demonstrated to be the main active species for the degradation of RhB and BPA

Piezoelectric properties enhanced of Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} ceramic by (LiCe) modification with charge neutrality

Energy Technology Data Exchange (ETDEWEB)

Fang, Pinyang, E-mail: fpy_2000@163.com [Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); Xi, Zengzhe; Long, Wei; Li, Xiaojuan [Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); Li, Jin [Northwest Institute For Non-ferrous Metal Research, Xi’an 710016 (China)

2013-09-01

Graphical abstract: The oxygen vacancies were confirmed by the left figure. The role of oxygen vacancy on piezoelectric activities was obtained by comparing to the varieties of oxygen vacancy concentration and piezoelectric coefficient with (LiCe) modification. -- Highlights: • The Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} ceramic by (LiCe) modification with the charge neutrality was synthesized by the solid state reaction method. • The Curie temperature and piezoelectric coefficient were found to be T{sub c} ∼590 °C and d{sub 33} ∼32 pC/N, respectively. • The mechanism of piezoelectric activities improved by (LiCe) modification was discussed. -- Abstract: Aurivillius-type ceramics, Sr{sub 0.6−x}(LiCe){sub x/2.5}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9}(SLCBNBNO) with the charge neutrality, were synthesized by using conventional solid-state processing. Phase analysis was performed by X-ray diffraction analyses (XRD) and Raman spectroscopy. Microstructural morphology was assessed by the scanning electron microscopy (SEM). Structural, dielectric, piezoelectric, ferroelectric, and electromechanical properties of the SLCBNBNO ceramics were investigated. Piezoelectric properties were significantly enhanced compared to Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} (SBNBN) ceramic and the maximum of piezoelectric coefficient d{sub 33} of the SBNBN-LC6 ceramic was 32 pC/N with higher Curie temperature (T{sub c} ∼590 °C). In addition, mechanisms for the piezoelectric properties enhanced of the SBNBN-based ceramics were discussed.

Like Fun Quantitative and Qualitative Analysis of the Entertainment Programs in BiH

Directory of Open Access Journals (Sweden)

Sanja Dokić Mrša

2015-09-01

Full Text Available According to the data from the Communications Regulatory Agency of Bosnia and Herzegovina, entertaining programme constitutes a quarter of all TV stations broadcast (24.9% and more than half of radio stations broadcast (53.66%. The content analysis of television programmes of three public broadcasters (BHT 1, RTRS, FTV as well as two commercial TV stations with nationwide coverage (TV Hayat and TV BN in prime time (from 17 to 23 hours on weekly base, based on the review of the programmes, showed that entertainment is one of the most important segments of television programmes, on both commercial TV stations, as well as public service in BiH. Qualitative analysis of Grand Show, that stands for the one of the most popular music and entertainment shows, not only in BiH, but wider, for almost two decades, indicates that this show belongs to kitsch culture. Furthermore, certain similarities between reality show programs like Big Brother or Farm and french Theatre of the absurd were found.

Bi2212 HTS Tubular Bulk with Conical Shape for Current Lead

International Nuclear Information System (INIS)

Tamura, H; Mito, T; Yamada, Y; Watanabe, M; Ohkubo, J; Heller, R

2006-01-01

Current leads using HTS material have been developed for application in a large scale superconducting magnet system. Tokai University and NIFS have developed Bi2212 tubular bulk which was prepared by a diffusion process. 8 kA of maximum transport current was achieved by a tubular bulk with a cylindrical shape. The maximum current was estimated to be 2 kA at 50 K for this tubular bulk. A current lead can be designed with this bulk the warm end of the HTS part being at 50 K and the cold end at 4.2 K. Under this condition, the cross section of the cold end of the bulk can be reduced. This type of HTS bulk has a great potential for flexible design since the Bi2212 layer can be reacted on the surface of any shapes of substrate. If a conical shaped HTS bulk was made, it could be an advantage for heat leakage to the cold end. To confirm this effect, we have made two types of conical bulk. The transport current of the specimen exceeds 7 kA at 4.2 K and 4 kA of stable current flow was achieved with a warm end temperature of 50 K

Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO{sub 3} thin film

Energy Technology Data Exchange (ETDEWEB)

Gupta, Surbhi; Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi (India); Tomar, Monika [Department of Physics, Miranda Housea, University of Delhi, Delhi (India); James, A. R. [Defence Metallurgical Research Laboratory, Hyderabad (India); Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar [Department of Electrical and Computer Engineering, College of Engineering, University of Texas at SanAntonio, San Antonio 78249 (United States)

2014-06-21

Multiferroic Bismuth Ferrite (BiFeO{sub 3}) thin films with varying excess bismuth (Bi) concentration were grown by chemical solution deposition technique. Room temperature multiferroic properties (ferromagnetism, ferroelectricity, and piezoelectricity) of the deposited BiFeO{sub 3} thin films have been studied. High resolution X-ray diffraction and Raman spectroscopy studies reveal that the dominant phases formed in the prepared samples change continuously from a mixture of BiFeO{sub 3} and Fe{sub 2}O{sub 3} to pure BiFeO{sub 3} phase and, subsequently, to a mixture of BiFeO{sub 3} and Bi{sub 2}O{sub 3} with increase in the concentration of excess Bi from 0% to 15%. BiFeO{sub 3} thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (γ-Fe{sub 2}O{sub 3}). Deterioration in ferroic properties of BiFeO{sub 3} thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO{sub 3} thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 μC/cm{sup 2} and saturation magnetization 11.66 emu/g. The switching of fine spontaneous domains with applied dc bias has been observed using piezoresponse force microscopy in BiFeO{sub 3} thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO{sub 3} thin films exhibiting the improved multiferroic properties.

Investigating the Statistical Distribution of Learning Coverage in MOOCs

Directory of Open Access Journals (Sweden)

Xiu Li

2017-11-01

Full Text Available Learners participating in Massive Open Online Courses (MOOC have a wide range of backgrounds and motivations. Many MOOC learners enroll in the courses to take a brief look; only a few go through the entire content, and even fewer are able to eventually obtain a certificate. We discovered this phenomenon after having examined 92 courses on both xuetangX and edX platforms. More specifically, we found that the learning coverage in many courses—one of the metrics used to estimate the learners’ active engagement with the online courses—observes a Zipf distribution. We apply the maximum likelihood estimation method to fit the Zipf’s law and test our hypothesis using a chi-square test. In the xuetangX dataset, the learning coverage in 53 of 76 courses fits Zipf’s law, but in all of 16 courses on the edX platform, the learning coverage rejects the Zipf’s law. The result from our study is expected to bring insight to the unique learning behavior on MOOC.

Investigation of the electronic structure of the BiSBr and BiSeBr clusters by density functional method

International Nuclear Information System (INIS)

Audzijonis, A.; Gaigalas, G.; Zigas, L.; Pauliukas, A.; Zaltauskas, R.; Kvedaravicius, A.; Cerskus, A.

2008-01-01

The energy levels of valence bands (VB) of the BiSBr and BiSeBr crystals have been calculated for investigation of the photoelectron emission spectra of BiSBr, BiSeBr and BiSI crystals. The molecular model of this crystal has been used for the calculation of VB by the Density Functional Theory (DFT) method. The molecular cluster, consisting of 20 molecules of BiSBr, BiSeBr, has been used for calculations of averaged total density of states, including atom vibrations. The spectra of the averaged total density of states from VB of BiSBr and BiSeBr clusters have been compared with the experimental photoelectron emission spectra from VB of BiSI crystals. The results clarify that the atomic vibrations in A 5 B 6 C 7 type crystals with chain structure create a smoother appearance of the averaged total density of state spectrum and the experimental X-ray photoemission spectra (XPS)

Effective visible light-active nitrogen and samarium co-doped BiVO{sub 4} for the degradation of organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Wang, Min; Niu, Chao [College of Environmental and Chemical Engineering, Shenyang Ligong University, Shenyang 110165 (China); Liu, Jun, E-mail: minwang62@msn.com [Shenyang Military General Hospital, Shenyang 110016 (China); Wang, Qianwu; Yang, Changxiu; Zheng, Haoyan [College of Environmental and Chemical Engineering, Shenyang Ligong University, Shenyang 110165 (China)

2015-11-05

Nitrogen and samarium co-doped BiVO{sub 4} (N–xSm–BiVO{sub 4}) nanoparticles were synthesized using a sol–gel method with a corn stem template. The physicochemical properties of the resultant N–xSm–BiVO{sub 4} particles were characterized using various methods: XPS, XRD, SEM, BET, and UV–Vis DRS analyses. The visible-light photocatalytic activity was successfully demonstrated by degrading a model dye, namely, methyl orange. The dopant content was optimized, and the nitrogen and samarium co-doped BiVO{sub 4} extended the light absorption spectrum toward the visible region, significantly enhancing the photodegradation of the model dye. The Sm and N co-doped BiVO{sub 4} exhibited the highest photocatalytic activity compared to materials with a single dopant or no dopant. The significantly enhanced photocatalytic activity of the N–Sm co-doped BiVO{sub 4} under visible-light irradiation can be attributed to the synergistic effects of the nitrogen and samarium. - Highlights: • The N–Sm codoped BiVO{sub 4} were synthesized using a sol–gel method with a corn stem template. • The N and Sm codoped BiVO{sub 4} has excellent photocatalytic activity of methyl orange degradation. • The maximum activity was observed when the molar ratio of Sm/Bi was 1.0. • The high photocatalytic activity was caused by the synergistic effects between N doping and Sm doping.

The thermal stability of magnetically exchange coupled MnBi/FeCo composites at electric motor working temperature

Science.gov (United States)

Cheng, Ye; Wang, Hongying; Li, Zhigang; Liu, Wanhui; Bao, Ilian

2018-04-01

The magnetically exchange coupled MnBi/FeCo composites were synthesized through a magnetic self-assembly process. The MnBi/FeCo composites were then hot pressed in a magnetic field to form magnets. The thermal stability of the magnets were tested by annealing at electric motor working temperature of 200 °C for 20, 40 and 60 h, respectively. It was found that after heating for 20 h, there was negligible change in its hysteresis loop. However, when the heating time was increased 40 and 60 h, the magnetic hysteresis loops presented two-phase magnetic behaviors, and the maximum energy products of the magnet were decreased. This research showed that the magnetically exchange coupled MnBi/FeCo composites had low thermal stability at electric motor working temperature.

The preparation and characterization of Bi-2212 film on Ag substrate by dip-coating method

International Nuclear Information System (INIS)

Song Yang; Zhao Liang; Li Pei; Qu Timing; Huang Yong; Han Zhenghe

2006-01-01

In this paper we report on the processing parameters and resulting critical current densities of Bi 2 Sr 2 Ca 1 Cu 2 O x thick films on Ag substrate. Bi-2212 tapes and wires are prepared by dip-coating method. It is found that parameters during partial melting (maximum process temperature T max and solidification temperature T s ) have strong influences on the transition temperature T c . The 0.5 mm diameter dip-coated wire can carry 4000 A/cm 2 critical current in 77 K, self field. Post-annealing on different temperatures and atmospheres are studied as well to obtain varied T c samples

Disparities in Private Health Insurance Coverage of Skilled Care

Directory of Open Access Journals (Sweden)

Stacey A. Tovino

2017-10-01

Full Text Available This article compares and contrasts public and private health insurance coverage of skilled medical rehabilitation, including cognitive rehabilitation, physical therapy, occupational therapy, speech-language pathology, and skilled nursing services (collectively, skilled care. As background, prior scholars writing in this area have focused on Medicare coverage of skilled care and have challenged coverage determinations limiting Medicare coverage to beneficiaries who are able to demonstrate improvement in their conditions within a specific period of time (the Improvement Standard. By and large, these scholars have applauded the settlement agreement approved on 24 January 2013, by the U.S. District Court for the District of Vermont in Jimmo v. Sebelius (Jimmo, as well as related motions, rulings, orders, government fact sheets, and Medicare program manual statements clarifying that Medicare covers skilled care that is necessary to prevent or slow a beneficiary’s deterioration or to maintain a beneficiary at his or her maximum practicable level of function even though no further improvement in the beneficiary’s condition is expected. Scholars who have focused on beneficiaries who have suffered severe brain injuries, in particular, have framed public insurance coverage of skilled brain rehabilitation as an important civil, disability, and educational right. Given that approximately two-thirds of Americans with health insurance are covered by private health insurance and that many private health plans continue to require their insureds to demonstrate improvement within a short period of time to obtain coverage of skilled care, scholarship assessing private health insurance coverage of skilled care is important but noticeably absent from the literature. This article responds to this gap by highlighting state benchmark plans’ and other private health plans’ continued use of the Improvement Standard in skilled care coverage decisions and

Phase equilibria and homogeneity range of the high temperature superconducting compound (Bi,Pb)2+xSr2Ca2Cu3O10+δ

International Nuclear Information System (INIS)

Kaesche, S.

1995-01-01

For the superconducting cuprates (Bi,Pb) 2+x Sr 2 Ca 2 Cu 3 O 10+y phase equilibria, the homogeneity region, and the phase formation has been studied in the temperture range 800 to 890 C. Sintered samples were prepared by a solid state reaction starting from Bi 2 O 3 , PbO, CuO and carbonates CaCO 3 and SrCO 3 in a three-stage calcination process. For the phase identification polarization microscopy, X-ray diffraction and susceptibility measurements have been applied. Multi-phase regions were determined in the cross section of the quasi-ternary system (Bi,Pb) 2 O 3 -SrO-CaO-CuO with constant Bi/(Bi+Pb) ratio 0.84 taking into account the 2223-phase. The homogeneity region was determined as function of Sr, Ca, Bi and Pb concentration. Its maximum size was found at 850 C

Luminescence of Bi3+ ions in Y3Al5O12:Bi single crystalline films

International Nuclear Information System (INIS)

Zorenko, Yu.; Gorbenko, V.; Voznyak, T.; Vistovsky, V.; Nedilko, S.; Nikl, M.

2007-01-01

The absorption and cathodoluminescence spectra of single crystalline films (SCF) of Y 3 Al 5 O 12 :Bi garnet depending on Bi concentration were analyzed. For consideration of the nature of the UV and visible Bi-related emission bands the time-resolved luminescence of Bi 3+ (ns 2 ) ions in YAG:Bi SCF was studied at 10 K under excitation by synchrotron radiation. The difference in the excitation spectra and emission decay of the UV and visible bands has been explained via radiative relaxation from the 3 P 1,0 excited states to the 1 S 0 ground state of the isolated and pair/clustered Bi 3+ emission centers in the garnet lattice, respectively

Diode-pumped CW frequency-doubled Nd:CNGG-BiBO blue laser at 468 nm

International Nuclear Information System (INIS)

Lü, Y F; Xia, J; Lin, J Q; Gao, X; Dong, Y; Xu, L J; Sun, G C; Zhao, Z M; Tan, Y; Chen, J F; Liu, Z X; Li, C L; Cai, H X; Liu, Z T; Ma, Z Y; Ning, G B

2011-01-01

Efficient and compact blue laser output at 468 nm is generated by intracavity frequency doubling of a continuous-wave (CW) diode-pumped Nd:CNGG laser at 935 nm. With 17.8 W of diode pump power and the frequency-doubling crystal BiB 3 O 6 (BiBO), a maximum output power of 490 mW in the blue spectral range at 468 nm has been achieved, corresponding to an optical-to-optical conversion efficiency of 2.8%; the output power stability over 4 h is better than 2.6%. To the best of our knowledge, this is first work on intracavity frequency doubling of a diode pumped Nd:CNGG laser at 935 nm

Response of MnBi-Bi eutectic to freezing rate changes

Science.gov (United States)

Nair, M.; Fu, T.-W.; Wilcox, W. R.; Doddi, K.; Ravishankar, P. S.; Larson, D.

1982-01-01

Reference is made to a study by Fu and Wilcox (1981), which treated theoretically the influence on freezing rate of sudden changes in translation rate in the Bridgman-Stockbarger technique. This treatment is extended here to a linear ramped translation rate and an oscillatory freezing rate. It is found that oscillations above a few hertz are highly damped in small-diameter apparatus. An experimental test is carried out of the theoretical predictions for a sudden change of translation rate. The MnBi-Bi eutectic is solidified with current-induced interface demarcation. The experimental results accord reasonably well with theory if the silica ampoule wall is assumed to either (1) contribute only a resistance to heat exchange between the sample and the furnace wall or (2) transmit heat effectively in the axial direction by radiation. In an attempt to explain the fact that a finer microstructure is obtained in space, MnBi-Bi microstructure is determined when the freezing rate is increased or decreased rapidly. Preliminary results suggest that fiber branching does not occur as readily as fiber termination.

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.

Medicare Coverage Database

Data.gov (United States)

U.S. Department of Health & Human Services — The Medicare Coverage Database (MCD) contains all National Coverage Determinations (NCDs) and Local Coverage Determinations (LCDs), local articles, and proposed NCD...

Adsorption-controlled growth of BiFeO3 by MBE and integration with wide band gap semiconductors.

Science.gov (United States)

Ihlefeld, Jon F; Tian, Wei; Liu, Zi-Kui; Doolittle, W Alan; Bernhagen, Margitta; Reiche, Peter; Uecker, Reinhard; Ramesh, Ramamoorthy; Schlom, Darrell G

2009-08-01

BiFeO3 thin films have been deposited on (001) SrTiO3, (101) DyScO3, (011) DyScO3, (0001) AlGaN/GaN, and (0001) 6H-SiC single crystal substrates by reactive molecular beam epitaxy in an adsorption-controlled growth regime. This is achieved by supplying a bismuth over-pressure and utilizing the differential vapor pressures between bismuth oxides and BiFeO3 to control stoichiometry in accordance with thermodynamic calculations. Four-circle x-ray diffraction and transmission electron microscopy reveal phase-pure, epitaxial films with rocking curve full width at half maximum values as narrow as 7.2 arc seconds (0.002 degrees). Epitaxial growth of (0001)-oriented BiFeO3 thin films on (0001) GaN, including AlGaN HEMT structures, and (0001) SiC has been realized using intervening epitaxial (111) SrTiO3 / (100) TiO2 buffer layers. The epitaxial BiFeO3 thin films have 2 in-plane orientations: [1120] BiFeO3 || [1120] GaN (SiC) plus a twin variant related by a 180 degrees in-plane rotation. This epitaxial integration of the ferroelectric with the highest known polarization, BiFeO3, with high bandgap semiconductors is an important step toward novel field-effect devices.

DFT study on the interfacial properties of vertical and in-plane BiOI/BiOIO3 hetero-structures.

Science.gov (United States)

Dai, Wen-Wu; Zhao, Zong-Yan

2017-04-12

Composite photocatalysts with hetero-structures usually favor the effective separation of photo-generated carriers. In this study, BiOIO 3 was chosen to form a hetero-structure with BiOI, due to its internal polar field and good lattice matching with BiOI. The interfacial properties and band offsets were focused on and analyzed in detail by DFT calculations. The results show that the charge depletion and accumulation mainly occur in the region near the interface. This effect leads to an interfacial electric field and thus, the photo-generated electron-hole pairs can be easily separated and transferred along opposite directions at the interface, which is significant for the enhancement of the photocatalytic activity. Moreover, according to the analysis of band offsets, the vertical BiOI/BiOIO 3 belongs to the type-II hetero-structure, while the in-plane BiOI/BiOIO 3 belongs to the type-I hetero-structure. The former type of hetero-structure has more favorable effects to enhance the photocatalytic activity of BiOI than that of the latter type of hetero-structure. In the case of the vertical BiOI/BiOIO 3 hetero-structure, photo-generated electrons can move from the conduction band of BiOI to that of BiOIO 3 , while holes can move from the valence band of BiOIO 3 to that of BiOI under solar radiation. In addition, the introduced internal electric field functions as a selector that can promote the separation of photo-generated carriers, resulting in the higher photocatalytic quantum efficiency. These findings illustrate the underlying mechanism for the reported experiments, and can be used as a basis for the design of novel highly efficient composite photocatalysts with hetero-structures.

Insight into the epitaxial growth of high optical quality GaAs{sub 1–x}Bi{sub x}

Energy Technology Data Exchange (ETDEWEB)

Beaton, D. A., E-mail: daniel.beaton@nrel.gov; Mascarenhas, A.; Alberi, K. [National Renewable Energy Laboratory (NREL), Golden, Colorado 80401 (United States)

2015-12-21

The ternary alloy GaAs{sub 1–x}Bi{sub x} is a potentially important material for infrared light emitting devices, but its use has been limited by poor optical quality. We report on the synthesis of GaAs{sub 1–x}Bi{sub x} epi-layers that exhibit narrow, band edge photoluminescence similar to other ternary GaAs based alloys, e.g., In{sub y}Ga{sub 1–y}As. The measured spectral linewidths are as low as 14 meV and 37 meV at low temperature (6 K) and room temperature, respectively, and are less than half of previously reported values. The improved optical quality is attributed to the use of incident UV irradiation of the epitaxial surface and the presence of a partial surface coverage of bismuth in a surfactant layer during epitaxy. Comparisons of samples grown under illuminated and dark conditions provide insight into possible surface processes that may be altered by the incident UV light. The improved optical quality now opens up possibilities for the practical use of GaAs{sub 1–x}Bi{sub x} in optoelectronic devices.

Strongly compressed Bi (111) bilayer films on Bi{sub 2}Se{sub 3} studied by scanning tunneling microscopy

Energy Technology Data Exchange (ETDEWEB)

Zhang, K. F.; Yang, Fang; Song, Y. R. [Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Liu, Canhua; Qian, Dong; Gao, C. L.; Jia, Jin-Feng [Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093 (China)

2015-09-21

Ultra-thin Bi films show exotic electronic structure and novel quantum effects, especially the widely studied Bi (111) film. Using reflection high-energy electron diffraction and scanning tunneling microscopy, we studied the structure and morphology evolution of Bi (111) thin films grown on Bi{sub 2}Se{sub 3}. A strongly compressed, but quickly released in-plane lattice of Bi (111) is found in the first three bilayers. The first bilayer of Bi shows a fractal growth mode with flat surface, while the second and third bilayer show a periodic buckling due to the strong compression of the in-plane lattice. The lattice slowly changes to its bulk value with further deposition of Bi.

An ion exchange strategy to BiOI/CH{sub 3}COO(BiO) heterojunction with enhanced visible-light photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Han, Qiaofeng, E-mail: hanqiaofeng@njust.edu.cn; Yang, Zhen; Wang, Li; Shen, Zichen; Wang, Xin; Zhu, Junwu; Jiang, Xiaohong

2017-05-01

Highlights: • BiOI/BiOAc heterojunction was firstly synthesized by an ion exchange route. • BiOI/BiOAc exhibited enhanced visible-light-driven photoreactivity for the dyes degradation in comparison with individuals. • Photocatalytic activity of the as-prepared BiOI/BiOAc is better than that prepared by precipitation-deposition method. • Photosensitization effect of BiOI to BiOAc was superior to that of Bi{sub 2}S{sub 3} due to suitable solubility constant. - Abstract: It is very significant to develop CH{sub 3}COO(BiO) (denoted as BiOAc) based photocatalysts for the removal of pollutants due to its non-toxicity and availability. We previously reported that BiOAc exhibited excellent photocatalytic activity for rhodamine B (RhB) degradation under UV light irradiation. Herein, by an ion exchange approach, BiOI/BiOAc heterojunction could be easily obtained. The as-prepared heterojunction possessed enhanced photodegradation activity for multiple dyes including RhB and methyl orange (MO) under visible light illumination in comparison with individual materials. Good visible-light photocatalytic activity of the heterojunction could be attributed to the increased visible light response, effective charge transfer from the modified band position and close interfacial contact due to partial ion exchange method.

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.

Local variation in Bi crystal sites of epitaxial GaAsBi studied by photoelectron spectroscopy and first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Laukkanen, P., E-mail: pekka.laukkanen@utu.fi [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Punkkinen, M.P.J., E-mail: marko.punkkinen@utu.fi [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Lahti, A. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Puustinen, J. [Optoelectronics Research Centre, Tampere University of Technology, FI-33101 Tampere (Finland); Tuominen, M. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Hilska, J. [Optoelectronics Research Centre, Tampere University of Technology, FI-33101 Tampere (Finland); Mäkelä, J.; Dahl, J.; Yasir, M. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Kuzmin, M. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021, Russian Federation (Russian Federation); Osiecki, J.R.; Schulte, K. [The MAX IV laboratory, P. O. Box 118, Lund University, SE-221 00 Lund (Sweden); Guina, M. [Optoelectronics Research Centre, Tampere University of Technology, FI-33101 Tampere (Finland); Kokko, K. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland)

2017-02-28

Highlights: • XPS is used to study bulk-like properties of GaAsBi crystals. • Surface effects are removed from XPS signal by an epitaxial AlAs cap film. • Local variation of Bi composition is found. • The result is consistent with photoluminescence and theoretical results. • Ga vacancies and Bi crystallites are suggested to be dominating defects. - Abstract: Epitaxial Bi-containing III–V crystals (III-V{sub 1-x}Bi{sub x}) have attracted increasing interest due to their potential in infrared applications. Atomic-scale characterization and engineering of bulk-like III-V{sub 1-x}Bi{sub x} properties (e.g., Bi incorporation and defect formation) are challenging but relevant to develop applications. Toward that target, we report here that the traditional surface-science measurement of photoelectron spectroscopy (PES) is a potential, non-destructive method to be combined in the studies of bulk-like properties, when surface effects are properly removed. We have investigated epitaxial GaAs{sub 1-x}Bi{sub x} films, capped by epitaxial AlAs layers, with high-resolution photoelectron spectroscopy. The Bi5d core-level spectra of GaAs{sub 1-x}Bi{sub x} together with ab-initio calculations give direct evidence of variation of Bi bonding environment in the lattice sites. The result agrees with photoluminescence (PL) measurement which shows that the studied GaAs{sub 1-x}Bi{sub x} films include local areas with higher Bi content, which contribute to PL but do not readily appear in x-ray diffraction (XRD). The measured and calculated Bi core-level shifts show also that Ga vacancies and Bi clusters are dominant defects.

Effect of diamagnetic barium substitution on magnetic and photovoltaic properties in multiferroic BiFeO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Hung, C.-M. [Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China); Tu, C. S., E-mail: 039611@mail.fju.edu.tw [Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China); Department of Physics, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China); Xu, Z.-R.; Chang, L.-Y. [Department of Physics, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China); Schmidt, V. H.; Chien, R. R. [Department of Physics, Montana State University, Bozeman, Montana 59717 (United States); Chang, W. C. [Department of Physics, National Chung Cheng University, Chia-Yi 621, Taiwan (China)

2014-05-07

Spontaneous magnetization and photovoltaic (PV) effects have been measured in (Bi{sub 1-x}Ba{sub x})FeO{sub 3-δ} ceramics for x = 0.05, 0.10, and 0.15. The substitution of Ba{sup 2+} ion in the A site of the perovskite unit cell can effectively enhance the ferromagnetic magnetization. The heterostructure of indium tin oxide (ITO) film/(Bi{sub 1-x}Ba{sub x})FeO{sub 3-δ} ceramic/Au film exhibits significant PV effects under illumination of λ = 405 nm. The PV responses decrease with increasing Ba concentration. The maximum power-conversion efficiency in the ITO/(Bi{sub 0.95}Ba{sub 0.5})FeO{sub 2.95}/Au can reach 0.006%. A theoretical model based on optically excited current in the depletion region between ITO film and (Bi{sub 1-x}Ba{sub x})FeO{sub 3-δ} ceramics is used to describe the I-V characteristic, open-circuit voltage (V{sub oc}), and short-circuit current density (J{sub sc}) as a function of light intensity.

Analysis of Bi-directional Effects on the Response of a Seismic Base Isolation System

International Nuclear Information System (INIS)

Park, Hyung-Kui; Kim, Jung-Han; Kim, Min Kyu; Choi, In-Kil

2014-01-01

The floor response spectrum depends on the height of the floor of the structure. Also FRS depends on the characteristics of the seismic base isolation system such as the natural frequency, damping ratio. In the previous study, the floor response spectrum of the base isolated structure was calculated for each axis without considering bi-directional effect. However, the shear behavior of the seismic base isolation system of two horizontal directions are correlated each other by the bi-directional effects. If the shear behavior of the seismic isolation system changes, it can influence the floor response spectrum and displacement response of isolators. In this study, the analysis of a bi-directional effect on the floor response spectrum was performed. In this study, the response of the seismic base isolation system based on the bi-directional effects was analyzed. By analyzing the time history result, while there is no alteration in the maximum shear force of seismic base isolation system, it is confirmed that the shear force is generally more decreased in a one-directional that in a two-directional in most parts. Due to the overall decreased shear force, the floor response spectrum is more reduced in a two-directional than in a one-directional

Thermoelectric properties of Co4Sb12 with Bi2Te3 nanoinclusions.

Science.gov (United States)

Ghosh, Sanyukta; Bisht, Anuj; Karati, Anirudha; Rogl, Gerda; Rogl, Peter; Murty, B S; Suwas, Satyam; Mallik, Ramesh Chandra

2018-02-12

The figure of merit (zT) of a thermoelectric material can be enhanced by incorporation of nanoinclusions into bulk material. The presence of bismuth telluride (Bi 2 Te 3 ) nanoinclusions in Co 4 Sb 12 leads to lower phonon thermal conductivity by introducing interfaces and defects; it enhances the average zT between 300-700 K. In the current study, Bi 2 Te 3 nanoparticles were dispersed into bulk Co 4 Sb 12 by ball-milling. The bulk was fabricated by spark plasma sintering. The presence of Bi 2 Te 3 dispersion in Co 4 Sb 12 was confirmed by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and electron back scattered diffraction technique. Energy dispersive spectroscopy showed antimony (Sb) as an impurity phase for higher contents of Bi 2 Te 3 in the sample. The Seebeck coefficient (S) and electrical conductivity (σ) were measured in the temperature range of 350-673 K. The negative value of S indicates that most of the charge carriers were electrons. A decrease in S and increase in σ with Bi 2 Te 3 content are due to the increased carrier concentration, as confirmed by Hall measurement. The thermal conductivity, measured between 423-673 K, decreased due to the increased phonon scattering at interfaces. A maximum zT of 0.17 was achieved at 523 K and it did not vary much throughout the temperature range. The experimental results of composites were compared by using effective medium theories.

Thermoelectric properties of Co4Sb12 with Bi2Te3 nanoinclusions.

Science.gov (United States)

Ghosh, Sanyukta; Bisht, Anuj; Karati, Anirudha; Rogl, Gerda; Rogl, Peter F; Murty, B S; Suwas, Satyam; Mallik, Ramesh Chandra

2018-01-08

The figure of merit (zT) of a thermoelectric material can be enhanced by incorporation of nanoinclusions into bulk material. The presence of bismuth telluride (Bi2Te3) nanoinclusions in Co4Sb12 leads to lower phonon thermal conductivity by introducing interfaces and defects; it enhances the average zT between 300-700 K. In the current study, Bi2Te3 nanoparticles were dispersed into bulk Co4Sb12 by ball-milling. The bulk was fabricated by spark plasma sintering (SPS). The presence of Bi2Te3 dispersion in Co4Sb12 was confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron back scattered diffraction (EBSD) technique. Energy dispersive spectroscopy (EDS) showed antimony (Sb) as an impurity phase for higher contents of Bi2Te3 in the sample. The Seebeck coefficient (S) and electrical conductivity () were measured in the temperature range of 350 - 673 K. The negative value of S indicates that most of the charge carriers were electrons. A decrease in S and increase in with Bi2Te3 content are due to the increased carrier concentration, as confirmed by Hall measurement. The thermal conductivity, measured between 423 - 673 K, decreased due to the increased phonon scattering at interfaces. A maximum zT of 0.17 was achieved at 523 K and it did not vary much throughout the temperature range. The experimental results of composites were compared by using effective medium theories. © 2018 IOP Publishing Ltd.

Does it matter which Life Cycle Assessment (LCA) tool you choose? - a comparative assessment of SimaPro and GaBi

DEFF Research Database (Denmark)

Herrmann, Ivan Tengbjerg; Moltesen, Andreas

2015-01-01

SimaPro and GaBi are the leading software tools used for life cycle assessments. Assessing product systems applying the exact same unit process foundation would be expected to yield comparable result sets with either tool. The software performances are compared based on a random sample of 100 unit...... of these differences are so large that they could influence the conclusions. For some of the 100 unit processes, six elementary flows were inventoried differently in SimaPro and GaBi, with an extreme maximum comparative ratio of 109. The implementation of the impact assessment methodologies shows notable differences...... processes. The research question investigated here is; can there be a difference between SimaPro and GaBi influencing the results and the decisions based on them? In many cases the results are identical between SimaPro and GaBi or nearly so, but in other cases the results reveal differences. Some...

Calorimetric investigations of U-Bi system

International Nuclear Information System (INIS)

Agarwal, Renu; Joshi, A.R.

2013-01-01

U 0.333 Bi 0.667 is a compound that may form on breach of clad during reactor operation with metallic fuel and lead-bismuth coolant. Therefore, enthalpy of mixing of U-Bi liquid solution in limited composition range and enthalpy of formation of U 0.333 Bi 0.667 compound were measured by high temperature calorimetry. The enthalpy of mixing follows subregular solution model and enthalpy of formation U 0.333 Bi 0.667 from U(l) and Bi(l) at 843 K was -52.5 kJ/mol and -40.8 kJ/mol from U(s) and Bi(s) at 298.15 K. Both enthalpy of mixing and enthalpy of formation of intermetallic compound obtained experimentally were compared with Miedema model values. (author)

Exploratory Bi-factor Analysis: The Oblique Case

OpenAIRE

Jennrich, Robert L.; Bentler, Peter M.

2011-01-01

Bi-factor analysis is a form of confirmatory factor analysis originally introduced by Holzinger and Swineford (1937). The bi-factor model has a general factor, a number of group factors, and an explicit bi-factor structure. Jennrich and Bentler (2011) introduced an exploratory form of bi-factor analysis that does not require one to provide an explicit bi-factor structure a priori. They use exploratory factor analysis and a bi-factor rotation criterion designed to produce a rotated loading mat...

Unusual Concentration Induced Antithermal Quenching of the Bi(2+) Emission from Sr2P2O7:Bi(2.).

Science.gov (United States)

Li, Liyi; Peng, Mingying; Viana, Bruno; Wang, Jing; Lei, Bingfu; Liu, Yingliang; Zhang, Qinyuan; Qiu, Jianrong

2015-06-15

The resistance of a luminescent material to thermal quenching is essential for the application in high power LEDs. Usually, thermal luminescence quenching becomes more and more serious as the activator concentration increases. Conversely, we found here that a red phosphor Sr2P2O7:Bi(2+) is one of the exceptions to this as we studied the luminescence properties at low (10-300 K) and high (300-500 K) temperatures. As Bi(2+) ions are incorporated into Sr2P2O7, they exhibit the emissions at ∼660 and ∼698 nm at room temperature and are encoded, hereafter, as Bi(1) and Bi(2) due to the substitutions for two different crystallographic sites Sr(1) and Sr(2), respectively, in the compound. However, they will not substitute for these sites equally. At lower dopant concentration, they will occupy preferentially Sr(2) sites partially due to size match. As the concentration increases, more Bi(2+) ions start to occupy the Sr(1) sites. This can be verified by the distinct changes of emission intensity ratio of Bi(2) to Bi(1). As environment temperature increases, the thermal quenching happens, but it can be suppressed by the Bi(2+) concentration increase. This becomes even more pronounced in Bi(2+) heavily doped sample as we decompose the broad emission band into separated Bi(1) and Bi(2) Gaussian peaks. For the sample, the Bi(1) emission at ∼660 nm even shows antithermal-quenching particularly at higher temperatures. This phenomenon is accompanied by the blue shift of the overall emission band and almost no changes of lifetimes. A mechanism is proposed due to volume expansion of the unit cell, the increase of Bi(1) content, and temperature dependent energy transfer between Bi(2) and Bi(1). This work helps us better understand the complex luminescent behavior of Bi(2+) doped materials, and it will be helpful to design in the future the heavily doped phosphor for WLEDs with even better resistance to thermal quenching.

DeBi: Discovering Differentially Expressed Biclusters using a Frequent Itemset Approach

Directory of Open Access Journals (Sweden)

Vingron Martin

2011-06-01

Full Text Available Abstract Background The analysis of massive high throughput data via clustering algorithms is very important for elucidating gene functions in biological systems. However, traditional clustering methods have several drawbacks. Biclustering overcomes these limitations by grouping genes and samples simultaneously. It discovers subsets of genes that are co-expressed in certain samples. Recent studies showed that biclustering has a great potential in detecting marker genes that are associated with certain tissues or diseases. Several biclustering algorithms have been proposed. However, it is still a challenge to find biclusters that are significant based on biological validation measures. Besides that, there is a need for a biclustering algorithm that is capable of analyzing very large datasets in reasonable time. Results Here we present a fast biclustering algorithm called DeBi (Differentially Expressed BIclusters. The algorithm is based on a well known data mining approach called frequent itemset. It discovers maximum size homogeneous biclusters in which each gene is strongly associated with a subset of samples. We evaluate the performance of DeBi on a yeast dataset, on synthetic datasets and on human datasets. Conclusions We demonstrate that the DeBi algorithm provides functionally more coherent gene sets compared to standard clustering or biclustering algorithms using biological validation measures such as Gene Ontology term and Transcription Factor Binding Site enrichment. We show that DeBi is a computationally efficient and powerful tool in analyzing large datasets. The method is also applicable on multiple gene expression datasets coming from different labs or platforms.

EXTREMUS - the German solution for act of terrorism - non-nuclear risks coverage

International Nuclear Information System (INIS)

Harbrucker, D.

2004-01-01

As a consequence of the terrorist attacks of September 11, 2001 and the withdraw of reinsurance capacity worldwide for terrorism coverage under material damage policies EXTREMUS was founded on September 2nd, 2002 by the German insurance industry (shareholders are 16 (re) insurance groups operating in the country). EXTREMUS offers a maximum limit per insured of Euro 1,5 bn. and enjoys a warranty of the German Government to cover accumulation losses in xs of Euro 2.0 bn. up to Euro 10 bn. EXTREMUS only intervenes for policies exceeding Euro 25 mio. due to a self obligation of the primary market to maintain full coverage for smaller risks. Due to the demand of reinsurers losses caused by a b c weapons are excluded. Coverage is not available for nuclear power plants. The paper aims to deals with these issues in more details.(author)

High pressure synthesis of BiS2

DEFF Research Database (Denmark)

Søndergaard-Pedersen, Simone; Nielsen, Morten Bormann; Bremholm, Martin

crystal structures and electrical properties.1,2 Up until now, the most sulfur rich phase in the Bi-S phase diagram was Bi2S3.3 For BiS2 the Bi atoms have anisotropic charge distribution and more complex structures are expected when comparing the layered structures of transition metal dichalcogenides....... The possibilities of using high pressure synthesis to discover new phases in the Bi-S binary system were investigated as early as the 1960’s.4 The research led to discovery of a compound with BiS2 stoichiometry, but no structure solution of BiS2 was reported. A reason behind making this new phase is to study...... the physical properties since the related compound Bi2S3 is known to be a thermoelectric material.5 In this research the BiS2 compound was synthesized by a high pressure and high temperature method using a multi-anvil large volume press and the structure was solved by single crystal diffraction. The structure...

Internal friction behavior of liquid Bi-Sn alloys

International Nuclear Information System (INIS)

Wu Aiqing; Guo Lijun; Liu Changsong; Jia Erguang; Zhu Zhengang

2005-01-01

Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480 - bar Cand another at about 830 - bar C. Only a single internal-friction peak at about 830 - bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids

Internal friction behavior of liquid Bi-Sn alloys

Energy Technology Data Exchange (ETDEWEB)

Wu Aiqing [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Guo Lijun [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Liu Changsong [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Jia Erguang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Zhu Zhengang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China)]. E-mail: zgzhu@issp.ac.cn

2005-12-01

Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480{sup -}bar Cand another at about 830{sup -}bar C. Only a single internal-friction peak at about 830{sup -}bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids.

Solvothermal modification of BiOCl nanosheets with Bi nanoparticles using ascorbic acid as reductant and the superoxide radicals dominated photocatalytic performance

Science.gov (United States)

Cui, Zhankui; Gao, Keke; Ge, Suxiang; Fa, Wenjun

2017-11-01

BiOCl nanosheets were solvothermally modified with Bi nanoparticles (NPs) using ascorbic acid as the reductant. The structures of Bi/BiOCl composites were characterized by XRD, Raman spectroscopy, FTIR spectroscopy and SEM. The light absorption properties were measured by UV-vis-NIR spectroscopy. The photocatalytic performances were evaluated by photodegrading methyl orange (MO) and the photocatalytic mechanism was investigated using trapping experiments and a fluorescent probe method. The results show that Bi NPs are uniformly distributed on the surfaces of BiOCl nanosheets and the modification amount of Bi NPs could be well controlled because of the mild property of ascorbic acid as reducing agent. The photocatalytic activities for the composites are improved obviously and the best photocatalytic performance is obtained when the weight ratio of Bi and BiOCl is1:10 and the photochemical reaction rate is 3.5 times that of pure BiOCl nanosheets and 19.7 times of Bi powders. The enhanced photocatalytic efficiency is ascribed to the favorable formation of dominant \\cdot O2- radicals caused by the increased photoinduced electrons from both Bi NPs and BiOCl nanosheets.

Roles of Cu in the Enhanced Thermoelectric Properties in Bi0.5Sb1.5Te₃.

Science.gov (United States)

Hao, Feng; Qiu, Pengfei; Song, Qingfeng; Chen, Hongyi; Lu, Ping; Ren, Dudi; Shi, Xun; Chen, Lidong

2017-03-01

Recently, Cu-containing p-type Bi 0.5 Sb 1.5 Te₃ materials have shown high thermoelectric performances and promising prospects for practical application in low-grade waste heat recovery. However, the position of Cu in Bi 0.5 Sb 1.5 Te₃ is controversial, and the roles of Cu in the enhancement of thermoelectric performance are still not clear. In this study, via defects analysis and stability test, the possibility of Cu intercalation in p-type Bi 0.5 Sb 1.5 Te₃ materials has been excluded, and the position of Cu is identified as doping at the Sb sites. Additionally, the effects of Cu dopants on the electrical and thermal transport properties have been systematically investigated. Besides introducing additional holes, Cu dopants can also significantly enhance the carrier mobility by decreasing the Debye screen length and weakening the interaction between carriers and phonons. Meanwhile, the Cu dopants interrupt the periodicity of lattice vibration and bring stronger anharmonicity, leading to extremely low lattice thermal conductivity. Combining the suppression on the intrinsic excitation, a high thermoelectric performance-with a maximum thermoelectric figure of merit of around 1.4 at 430 K-has been achieved in Cu 0.005 Bi 0.5 Sb 1.495 Te₃, which is 70% higher than the Bi 0.5 Sb 1.5 Te₃ matrix.

Investigation of phases developed in Bi/sub 4/Ti/sub 3/O/sub 12/ system by thermal and analytical techniques

International Nuclear Information System (INIS)

Naz, S.; Shazad, S.; Qureshi, A.H.; Waqas, H.; Hussain, N.; Ahmed, N.; Saeed, K.; Ali, L.

2012-01-01

Bismuth titanate (Bi/sub 4/Ti/sub 3/O/sub 12/) powders were prepared by conventional mixed oxide method using oxide mixture i.e. bismuth oxide (Bi/sub 2/O/sub 3/) and titanium oxide (TiO/sub 3). The mixed powders were ball milled for different times (8, 16, and 24 hours). The phase formation was investigated by X-ray diffraction (XRD) and the results revealed that milled powder mainly consisted of Bi/sub 2/O/sub 3/ and TiO/sub 2 /phases and a small amount corresponded to Bi/sub 4/Ti/sub 3/O/sub 12/. However, after calcination at 700 deg. C, Bi/sub 4/Ti/sub 3/O/sub 12/ phase was mainly observed. Thermal decomposition (Differential Scanning Calorimetry (DSC)-Thermal Gravimetric Analysis (TGA)-Differential Thermometric Analysis (DTA)) and XRD results showed that the formation of desired phase Bi/sub 4/Ti/sub 3/O/sub 12/ was only possible above 600 deg. C. Single phase Bi/sub 4/Ti/sub 3/O/sub 12/ ceramic was obtained with the orthorhombic structure in three pellets by sintering at 800 deg. C. XRD patterns of sintered pellets are shown. Maximum density (8.61 g/cm/sup 3/) was achieved in the sample milled for 24 hours due to reduction in particle size which ultimately enhanced the diffusion process during sintering. (Orig./A.B.)

Enhanced photoluminescence of Sm{sup 3+}/Bi{sup 3+} co-doped Gd{sub 2}O{sub 3} phosphors by combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Liu Guangsheng; Zhang Ying [Institute of Micro-system Physics, School of Physics and Electronics, Henan University, Kaifeng 475001 (China); Yin Jiang [Department of Physics, Nanjing University, Nanjing 210093 (China); Zhang, W.F. [Institute of Micro-system Physics, School of Physics and Electronics, Henan University, Kaifeng 475001 (China)], E-mail: wfzhang@henu.edu.cn

2008-12-15

Gd{sub 2}O{sub 3}:Sm{sup 3+} and Gd{sub 2}O{sub 3}:Sm{sup 3+},Bi{sup 3+} powders were prepared by a combustion method. Their structures were determined using X-ray diffraction. UV-visible absorption and photoluminescence spectra were investigated for Gd{sub 2}O{sub 3}:Sm{sup 3+} and Gd{sub 2}O{sub 3}:Sm{sup 3+},Bi{sup 3+} at different annealing temperatures and different doping concentrations. The emission spectra of all samples presented the characteristic emission narrow lines arising from the {sup 4}G{sub 5/2}{yields}{sup 6}H{sub J} transitions (J=5/2, 7/2, and 9/2) of Sm{sup 3+} ions upon excitation with UV irradiation. The emission intensity of Sm{sup 3+} ions was largely enhanced with introducing Bi{sup 3+} ions into Gd{sub 2}O{sub 3}:Sm{sup 3+} and the maximum occurred at a Bi{sup 3+} concentration of 0.5 mol%. The relevant mechanisms were discussed with the sensitization theory by Dexter and the aggregation behavior of Bi{sup 3+} ions.

Phonons of single quintuple Bi 2 Te 3 and Bi 2 Se 3 films and bulk materials

KAUST Repository

Cheng, Wei; Ren, Shang-Fen

2011-01-01

Phonons of single quintuple films of Bi2Te3 and Bi2Se3 and corresponding bulk materials are calculated in detail by MedeA (a trademark of Materials Design) and Vienna ab initio simulation package (VASP). The calculated results with and without spin-orbit couplings are compared, and the important roles that the spin-orbit coupling plays in these materials are discussed. A symmetry breaking caused by the anharmonic potentials around Bi atoms in the single quintuple films is identified and discussed. The observed Raman intensity features in Bi 2Te3 and Bi2Se3 quintuple films are explained. © 2011 American Physical Society.

Phonons of single quintuple Bi 2 Te 3 and Bi 2 Se 3 films and bulk materials

KAUST Repository

Cheng, Wei

2011-03-10

Phonons of single quintuple films of Bi2Te3 and Bi2Se3 and corresponding bulk materials are calculated in detail by MedeA (a trademark of Materials Design) and Vienna ab initio simulation package (VASP). The calculated results with and without spin-orbit couplings are compared, and the important roles that the spin-orbit coupling plays in these materials are discussed. A symmetry breaking caused by the anharmonic potentials around Bi atoms in the single quintuple films is identified and discussed. The observed Raman intensity features in Bi 2Te3 and Bi2Se3 quintuple films are explained. © 2011 American Physical Society.

Demonstration of surface transport in a hybrid Bi2Se3/Bi2Te3 heterostructure

OpenAIRE

Zhao, Yanfei; Chang, Cui-Zu; Jiang, Ying; DaSilva, Ashley; Sun, Yi; Wang, Huichao; Xing, Ying; Wang, Yong; He, Ke; Ma, Xucun; Xue, Qi-Kun; Wang, Jian

2013-01-01

In spite of much work on topological insulators (TIs), systematic experiments for TI/TI heterostructures remain absent. We grow a high quality heterostructure containing single quintuple layer (QL) of Bi2Se3 on 19 QLs of Bi2Te3 and compare its transport properties with 20 QLs Bi2Se3 and 20 QLs Bi2Te3. All three films are grown on insulating sapphire (0001) substrates by molecular beam epitaxy (MBE). In situ angle-resolved photoemission spectroscopy (ARPES) provides direct evidence that the su...

Effect of oxidant on resputtering of Bi from Bi--Sr--Ca--Cu--O films

International Nuclear Information System (INIS)

Grace, J.M.; McDonald, D.B.; Reiten, M.T.; Olson, J.; Kampwirth, R.T.; Gray, K.E.

1992-01-01

The type and partial pressure of oxidant mixed with argon can affect the selective sputtering of Bi in composite-target, magnetron-sputtered Bi--Sr--Ca--Cu--O films. Comparative studies using oxygen and ozone show that ozone is a more potent oxidant, as well as a more potent source of resputterers than is oxygen. Severe resputtering from ozone is significantly reduced by a -40 V potential on the sample block. We suggest that oxygen causes resputtering by forming O + 2 , which interacts with the target to produce energetic O - . In contrast, ozone may form lower-energy O - by electron impact in the dark space. Negative oxygen ions from the target itself may be responsible for a background resputtering effect. Our results and those found for Y--Ba--Cu--O by others are comparable. Bi in Bi--Sr--Ca--Cu--O behaves as Ba in Y--Ba--Cu--O, with regard to selective resputtering; furthermore, the response of Sr, Ca, and Cu to oxygen in sputtered Bi--Sr--Ca--Cu--O is similar to what is observed for Cu in Y--Ba--Cu--O

Access to Medicines by Seguro Popular Beneficiaries: Pending Tasks towards Universal Health Coverage.

Directory of Open Access Journals (Sweden)

Edson Servan-Mori

Full Text Available In the context of aiming to achieve universal health coverage in Mexico, this study compares access to prescribed medicines (ATPM between Seguro Popular (SP and non-SP affiliated outpatient health service users.ATPM by 6,123 users of outpatient services was analyzed using the National Health and Nutrition Survey 2012. Adjusted bi-probit models were performed incorporating instrumental variables.17.3% of SP and 10.1% of the non-SP population lacked ATPM. Two-thirds of all outpatient SP and 18.5% of all outpatient non-SP received health services at Ministry of Health facilities, among whom, 64.6 and 53.6% of the SP and non-SP population respectively reported ATPM at these facilities. Lack of medicines in health units, chronic health problems (compared to acute conditions and prescription ≥3 medicines were risk factors for non-ATPM. Adjusted models suggest that when using Ministry of Health services, the SP population has a higher probability of ATMP compared to the non-SP population.Given the aspirations of achieving universal health coverage in Mexico, it is important to increase ATPM in Ministry of Health facilities thereby ensuring basic rights to health care are met.

Access to Medicines by Seguro Popular Beneficiaries: Pending Tasks towards Universal Health Coverage.

Science.gov (United States)

Servan-Mori, Edson; Heredia-Pi, Ileana; Montañez-Hernandez, Julio; Avila-Burgos, Leticia; Wirtz, Veronika J

2015-01-01

In the context of aiming to achieve universal health coverage in Mexico, this study compares access to prescribed medicines (ATPM) between Seguro Popular (SP) and non-SP affiliated outpatient health service users. ATPM by 6,123 users of outpatient services was analyzed using the National Health and Nutrition Survey 2012. Adjusted bi-probit models were performed incorporating instrumental variables. 17.3% of SP and 10.1% of the non-SP population lacked ATPM. Two-thirds of all outpatient SP and 18.5% of all outpatient non-SP received health services at Ministry of Health facilities, among whom, 64.6 and 53.6% of the SP and non-SP population respectively reported ATPM at these facilities. Lack of medicines in health units, chronic health problems (compared to acute conditions) and prescription ≥3 medicines were risk factors for non-ATPM. Adjusted models suggest that when using Ministry of Health services, the SP population has a higher probability of ATMP compared to the non-SP population. Given the aspirations of achieving universal health coverage in Mexico, it is important to increase ATPM in Ministry of Health facilities thereby ensuring basic rights to health care are met.

Comparative study of phase structure and dielectric properties for K0.5Bi0.5TiO3-BiAlO3 and LaAlO3-BiAlO3

International Nuclear Information System (INIS)

Hou, Yudong; Zheng, Mupeng; Si, Meiju; Cui, Lei; Zhu, Mankang; Yan, Hui

2013-01-01

In this work, two perovskite-type compounds, K 0.5 Bi 0.5 TiO 3 and LaAlO 3 , have been selected as host material to incorporate with BiAlO 3 using a solid-state reaction route. The phase evolution and dielectric properties for both systems have been investigated in detail. For the K 0.5 Bi 0.5 TiO 3 -BiAlO 3 system, it is interesting to find that when using Bi 2 O 3 , Al 2 O 3 , K 2 CO 3 , and TiO 2 as starting materials, the formed compounds are K 0.5 Bi 0.5 TiO 3 -K 0.5 Bi 4.5 Ti 4 O 15 and Al 2 O 3 only plays a dopant role. There are two distinct dielectric peaks appearing in the patterns of temperature dependence of dielectric constant, corresponding to the phase-transition points of perovskite-type K 0.5 Bi 0.5 TiO 3 and Aurivillius-type K 0.5 Bi 4.5 Ti 4 O 15 , independently. In comparison, using Bi 2 O 3 , Al 2 O 3 , and La 2 O 3 as starting materials, the pure perovskite phase LaAlO 3 -BiAlO 3 can be obtained. Compared to the inherent paraelectric behavior in LaAlO 3 , the diffuse phase-transition phenomena can be observed in the LaAlO 3 -BiAlO 3 binary system, which corresponds well to the Vogel-Fulcher (VF) relationship. Moreover, compared to pure LaAlO 3 , the synthesized LaAlO 3 -BiAlO 3 compound shows enhanced dielectric properties, which are promising in application as gate dielectric materials. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Preparation of (Bi, Pb)-2223/Ag tapes by high temperature sintering and post-annealing process

DEFF Research Database (Denmark)

Hua, L.; Grivel, Jean-Claude; Andersen, L.G.

2002-01-01

A novel heat treatment process was developed to fabricate (Bi, Pb)-2223/Ag tapes with high critical current density (J(c)). The process can be divided into two parts: reformation and post-annealing. Tapes were first heated to the maximum temperature (830-860 degreesC) followed by slow cooling...... (reformation). Then, tape, were annealed between 760 and 820 degreesC (post-annealing). Reformation is expected to produce a large amount of liquid phase which may heat microcracks, decrease porosity, and improve grain growth. However, since the sintering temperature is beyond the Bi-2223 single-phase region......-energy synchrotron XRD and SEM/EDX. Some process parameters e.g. sintering temperature. cooling rate. and post-annealing time were optimised. (C) 2002 Elsevier Science B.V. All rights reserved....

Crystalline structure and XMCD studies of Co40Fe40B20 grown on Bi2Te3, BiTeI and Bi2Se3

OpenAIRE

Kaveev, A. K.; Sokolov, N. S.; Suturin, S. M.; Zhiltsov, N. S.; Golyashov, V. A.; Tereshchenko, O. E.; Prosvirin, I. P.; Kokh, K. A.; Sawada, M.

2018-01-01

Epitaxial films of Co40Fe40B20 (further - CoFeB) were grown on Bi2Te3(001) and Bi2Se3(001) substrates by laser molecular beam epitaxy (LMBE) technique at 200-400C. Bcc-type crystalline structure of CoFeB with (111) plane parallel to (001) plane of Bi2Te3 was observed, in contrast to polycrystalline CoFeB film formed on Bi2Se3(001) at RT using high-temperature seeding layer. Therefore, structurally ordered ferromagnetic thin films were obtained on the topological insulator surface for the firs...

Thermal analysis and phase diagrams of the LiF BiF{sub 3} e NaF BiF{sub 3} systems; Analise termica e diagramas de fase dos sistemas LiF-BiF{sub 3} e NaF-BiF{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Gerson Hiroshi de Godoy

2013-07-01

Investigations of the binary systems LiF-BiF{sub 3} and NaF-BiF{sub 3} were performed with the objective of clarifying the thermal behavior and phase equilibria of these systems and their intermediary phases, an important requisite for high-quality crystal growth. Several samples in the entire range of compositions (0 to 100 mol% BiF{sub 3}) of both systems were subjected to experiments of differential thermal analysis (DTA) and thermogravimetry (TG), and also of differential scanning calorimetry (DSC). A few specific compositions were selected for X-ray diffraction to supplement the experimental data. Due to the high vulnerability of BiF{sub 3} to oxygen contamination, its volatility and propensity to destroy metal parts upon heating, it was necessary to determine the optimal conditions for thermal analysis before investigating the systems themselves. Phase relations in the system LiF-BiF{sub 3} were completely clarified and a phase diagram was calculated and evaluated via the commercial software Factsage. The diagram itself consists in a simple peritectic system in which the only intermediary compound, LiBiF{sub 4}, decomposes into LiF and a liquid phase. The NaF-BiF{sub 3} system could not be completely elucidated and the phase relations in the NaF poor side (> 50% BiF{sub 3}) are still unknown. In the NaF rich side, however, the possible peritectoid decomposition of the compound NaBiF{sub 4} was identified. In both systems X-ray diffraction yielded crystal structures discrepant with the literature for the intermediary phases, LiBiF{sub 4}, NaBiF{sub 4} and a solid solution of NaF and BiF{sub 3} called {sup I.} The observed structures remain unknown and explanations for the discrepancies were proposed. (author)

Highly efficient visible-light-induced photocatalytic activity of Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts

Energy Technology Data Exchange (ETDEWEB)

Chaiwichian, Saranyoo [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai50200 (Thailand); Inceesungvorn, Burapat [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wetchakun, Khatcharin [Program of Physics, Faculty of Science, Ubon Ratchathani Rajabhat University, Ubon Ratchathani 34000 (Thailand); Phanichphant, Sukon [Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Kangwansupamonkon, Wiyong [National Nanotechnology Center, Thailand Science Park, Phahonyotin Road, Klong 1, Klong Luang, Phathumthani 12120 (Thailand); Wetchakun, Natda, E-mail: natda_we@yahoo.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai50200 (Thailand)

2014-06-01

Highlights: • Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts were obtained using hydrothermal method. • Physicochemical properties played a significant role on photocatalytic efficiency. • Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterogeneous structures were greatly enhanced for degradation of MB. • A tentative mechanism of charge transfer process in MB degradation was proposed. - Abstract: The Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts were synthesized by hydrothermal method. Physical properties of the heterojunction photocatalyst samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The XRD results indicated that BiVO{sub 4} retain monoclinic and tetragonal structures, while Bi{sub 2}WO{sub 6} presented as orthorhombic structure. The Brunauer, Emmett and Teller (BET) adsorption–desorption of nitrogen gas for specific surface area determination at the temperature of liquid nitrogen was performed on all samples. UV–vis diffuse reflectance spectra (UV–vis DRS) were used to identify the absorption range and band gap energy of the heterojunction photocatalysts. The photocatalytic performance of Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts was studied via the photodegradation of methylene blue (MB) under visible light irradiation. The results indicated that the heterojunction photocatalyst at 0.5:0.5 mole ratio of Bi{sub 2}WO{sub 6}:BiVO{sub 4} shows the highest photocatalytic activity.

Exploratory Bi-Factor Analysis: The Oblique Case

Science.gov (United States)

Jennrich, Robert I.; Bentler, Peter M.

2012-01-01

Bi-factor analysis is a form of confirmatory factor analysis originally introduced by Holzinger and Swineford ("Psychometrika" 47:41-54, 1937). The bi-factor model has a general factor, a number of group factors, and an explicit bi-factor structure. Jennrich and Bentler ("Psychometrika" 76:537-549, 2011) introduced an exploratory form of bi-factor…

In-Situ Hydrothermal Synthesis of Bi-Bi2O2CO3 Heterojunction Photocatalyst with Enhanced Visible Light Photocatalytic Activity

Science.gov (United States)

Kar, Prasenjit; Maji, Tuhin Kumar; Nandi, Ramesh; Lemmens, Peter; Pal, Samir Kumar

2017-04-01

Bismuth containing nanomaterials recently received increasing attention with respect to environmental applications because of their low cost, high stability and nontoxicity. In this work, Bi-Bi2O2CO3 heterojunctions were fabricated by in-situ decoration of Bi nanoparticles on Bi2O2CO3 nanosheets via a simple hydrothermal synthesis approach. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) were used to confirm the morphology of the nanosheet-like heterostructure of the Bi-Bi2O2CO3 composite. Detailed ultrafast electronic spectroscopy reveals that the in-situ decoration of Bi nanoparticles on Bi2O2CO3 nanosheets exhibit a dramatically enhanced electron-hole pair separation rate, which results in an extraordinarily high photocatalytic activity for the degradation of a model organic dye, methylene blue (MB) under visible light illumination. Cycling experiments revealed a good photochemical stability of the Bi-Bi2O2CO3 heterojunction under repeated irradiation. Photocurrent measurements further indicated that the heterojunction incredibly enhanced the charge generation and suppressed the charge recombination of photogenerated electron-hole pairs.

Facile synthesis of BiOF/Bi{sub 2}O{sub 3}/reduced graphene oxide photocatalyst with highly efficient and stable natural sunlight photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Hu, Limin; Dong, Shuying; Li, Qilu; Feng, Jinglan; Pi, Yunqing; Liu, Menglin [School of Environment, Henan Normal University, Key Laboratory for Yellow River and Huai River Water Environmental and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Xinxiang, Henan 453007 (China); Sun, Jingyu, E-mail: sunjy-cnc@pku.edu.cn [Center for Nanochemistry (CNC), College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Sun, Jianhui, E-mail: sunjh@htu.cn [School of Environment, Henan Normal University, Key Laboratory for Yellow River and Huai River Water Environmental and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Xinxiang, Henan 453007 (China)

2015-06-05

Highlights: • A dual Bi-based ball-shaped material BiOF/Bi{sub 2}O{sub 3} were facilely synthesized. • The composition effect of BiOF/Bi{sub 2}O{sub 3}/RGO hybrid were probed for the first time. • The photocatalytic performances were evaluated upon natural sunlight irradiation. • The composites showed a twofold augmentation in the degradation efficiency. • The hybrid photocatalyst can be easily recycled for three times. - Abstract: A facile and efficient route for the controllable synthesis of BiOF/Bi{sub 2}O{sub 3} nanostructures by hydrolysis method was reported, where the as-prepared BiOF/Bi{sub 2}O{sub 3} was subsequently incorporated with reduced graphene oxide (RGO) sheets to form BiOF/Bi{sub 2}O{sub 3}/RGO composites. The obtained BiOF/Bi{sub 2}O{sub 3} and BiOF/Bi{sub 2}O{sub 3}/RGO composites were well characterized with the aid of various techniques to probe their crystallographic, morphological, chemical and optical properties. Photocatalytic capacities of the pure BiOF/Bi{sub 2}O{sub 3} and BiOF/Bi{sub 2}O{sub 3}/RGO composites have been investigated by the degradation of Rhodamine B (RhB)-contained wastewater under natural sunlight irradiation. A twofold augmentation of degradation efficiency was in turn observed for BiOF/Bi{sub 2}O{sub 3}/RGO composites compared with that of pure BiOF/Bi{sub 2}O{sub 3} under the natural sunlight irradiation. The optimum conditions, the effects of the active species and stabilities in photocatalytic performances of the BiOF/Bi{sub 2}O{sub 3}/RGO composites have also been probed.

Considerations about using OLAP Cubes and Self-Service BI Tools for BI Systems’ Development

Directory of Open Access Journals (Sweden)

Gianina MIHAI

2017-12-01

Full Text Available Nowadays, the decision-making process must be an extremely fast one. This is why any decision-maker in a company must obtain information from the multiple available data source used in its transactional systems as easily and as quickly as possible. Business Intelligence (BI systems are the ones that provide the tools necessary for obtaining this information. In this article, we shall present the strengths and weaknesses regarding data analyses in a BI system using OLAP cubes and self-service BI tools.

Bismuth oxychloride homogeneous phasejunction BiOCl/Bi12O17Cl2 with unselectively efficient photocatalytic activity and mechanism insight

Science.gov (United States)

Hao, Lin; Huang, Hongwei; Guo, Yuxi; Du, Xin; Zhang, Yihe

2017-10-01

Fabrication of homo/hetero-junctions by coupling of wide-band gap semiconductor and narrow-band gap semiconductor is desirable as they can achieve a decent balance between photoabsorption and photo-redox ability. Herein, a n-n type bismuth oxychloride homogeneous phasejunction BiOCl/Bi12O17Cl2 was developed by facilely manipulating the basicity in a one-pot hydrothermal process. Compared with BiOCl which only responds to UV light, the photo-responsive range is remarkably extended to visible region. The BiOCl/Bi12O17Cl2 phasejunctions show much higher photocatalytic activity than the single BiOCl and Bi12O17Cl2 toward degradation of methyl orange (MO) under simulated solar light. In particular, it presented a high photo-oxidation ability in degrading diverse industrial contaminants including 2,4-dichlorophenol (2,4-DCP), phenol, bisphenol A (BPA) and tetracycline hydrochloride. Based on a series of photoelectrochemical and photoluminescence measurements, the fortified photocatalytic performance of BiOCl/Bi12O17Cl2 phasejunctions was manifested to be attributed to the efficient separation and transfer efficiencies of photoinduced electron-hole pairs because of the junctional interface formed between BiOCl and Bi12O17Cl2. The study may not only furnish a high-effective photocatalyst in the application of environment purification, but also pave a path to fabricate agnate phase-junctional photocatalyst.

Thermal analysis and phase diagrams of the LiF BiF3 e NaF BiF3 systems

International Nuclear Information System (INIS)

Nakamura, Gerson Hiroshi de Godoy

2013-01-01

Investigations of the binary systems LiF-BiF 3 and NaF-BiF 3 were performed with the objective of clarifying the thermal behavior and phase equilibria of these systems and their intermediary phases, an important requisite for high-quality crystal growth. Several samples in the entire range of compositions (0 to 100 mol% BiF 3 ) of both systems were subjected to experiments of differential thermal analysis (DTA) and thermogravimetry (TG), and also of differential scanning calorimetry (DSC). A few specific compositions were selected for X-ray diffraction to supplement the experimental data. Due to the high vulnerability of BiF 3 to oxygen contamination, its volatility and propensity to destroy metal parts upon heating, it was necessary to determine the optimal conditions for thermal analysis before investigating the systems themselves. Phase relations in the system LiF-BiF 3 were completely clarified and a phase diagram was calculated and evaluated via the commercial software Factsage. The diagram itself consists in a simple peritectic system in which the only intermediary compound, LiBiF 4 , decomposes into LiF and a liquid phase. The NaF-BiF 3 system could not be completely elucidated and the phase relations in the NaF poor side (> 50% BiF 3 ) are still unknown. In the NaF rich side, however, the possible peritectoid decomposition of the compound NaBiF 4 was identified. In both systems X-ray diffraction yielded crystal structures discrepant with the literature for the intermediary phases, LiBiF 4 , NaBiF 4 and a solid solution of NaF and BiF 3 called I. The observed structures remain unknown and explanations for the discrepancies were proposed. (author)

Roles of Cu in the Enhanced Thermoelectric Properties in Bi0.5Sb1.5Te3

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Feng Hao

2017-03-01

Full Text Available Recently, Cu-containing p-type Bi0.5Sb1.5Te3 materials have shown high thermoelectric performances and promising prospects for practical application in low-grade waste heat recovery. However, the position of Cu in Bi0.5Sb1.5Te3 is controversial, and the roles of Cu in the enhancement of thermoelectric performance are still not clear. In this study, via defects analysis and stability test, the possibility of Cu intercalation in p-type Bi0.5Sb1.5Te3 materials has been excluded, and the position of Cu is identified as doping at the Sb sites. Additionally, the effects of Cu dopants on the electrical and thermal transport properties have been systematically investigated. Besides introducing additional holes, Cu dopants can also significantly enhance the carrier mobility by decreasing the Debye screen length and weakening the interaction between carriers and phonons. Meanwhile, the Cu dopants interrupt the periodicity of lattice vibration and bring stronger anharmonicity, leading to extremely low lattice thermal conductivity. Combining the suppression on the intrinsic excitation, a high thermoelectric performance—with a maximum thermoelectric figure of merit of around 1.4 at 430 K—has been achieved in Cu0.005Bi0.5Sb1.495Te3, which is 70% higher than the Bi0.5Sb1.5Te3 matrix.

Enhanced photocatalytic activity of Bi{sub 2}O{sub 3}–Ag{sub 2}O hybrid photocatalysts

Energy Technology Data Exchange (ETDEWEB)

Liu, Xinjuan, E-mail: lxj669635@126.com [Institute of Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China); Liu, Junying [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, Shanghai 200062 China (China); Chu, Haipeng [Institute of Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China); Li, Jinliang; Yu, Wei [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, Shanghai 200062 China (China); Zhu, Guang [Anhui Key Laboratory of Spin Electron and Nanomaterials, Suzhou University, Suzhou 234000 (China); Niu, Lengyuan [Institute of Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China); Sun, Zhuo [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, Shanghai 200062 China (China); Pan, Likun, E-mail: lkpan@phy.ecnu.edu.cn [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, Shanghai 200062 China (China); Sun, Chang Q. [Institute of Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China)

2015-08-30

Graphical abstract: Bi{sub 2}O{sub 3}–Ag{sub 2}O composites were fabricated for visible light photocatalytic degradation of phenol with a high degradation rate of 92% for 60 min. - Highlights: • Bi{sub 2}O{sub 3}–Ag{sub 2}O composites were synthesized via a co-precipitation method. • The photocatalytic activity for the degradation of phenol is investigated. • A high degradation rate of 92% for 60 min is achieved under visible light irradiation. - Abstract: Bi{sub 2}O{sub 3}–Ag{sub 2}O hybrid photocatalysts were successfully synthesized via a co-precipitation method. The morphology, structure and photocatalytic performance in the degradation of phenol were characterized by using scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, electrochemical impedance spectra and UV–vis absorption spectroscopy, respectively. The results show that Bi{sub 2}O{sub 3}–Ag{sub 2}O hybrid photocatalysts exhibit enhanced photocatalytic performance in the degradation of phenol with a maximum degradation rate of 92% for 60 min under visible light irradiation compared with pure Bi{sub 2}O{sub 3} (57%), which is ascribed to the increase in light adsorption and the reduction in electron–hole pair recombination with the introduction of Ag{sub 2}O.

First AC loss test and analysis of a Bi2212 cable-in-conduit conductor for fusion application

Science.gov (United States)

Qin, Jinggang; Shi, Yi; Wu, Yu; Li, Jiangang; Wang, Qiuliang; He, Yuxiang; Dai, Chao; Liu, Fang; Liu, Huajun; Mao, Zhehua; Nijhuis, Arend; Zhou, Chao; Devred, Arnaud

2018-01-01

The main goal of the Chinese fusion engineering test reactor (CFETR) is to build a fusion engineering tokamak reactor with a fusion power of 50-200 MW, and plan to test the breeding tritium during the fusion reaction. This may require a maximum magnetic field of the central solenoid and toroidal field coils up to 15 T. New magnet technologies should be developed for the next generation of fusion reactors with higher requirements. Bi2Sr2CaCu2Ox (Bi2212) is considered as a potential and promising superconductor for the magnets in the CFETR. R&D activities are ongoing at the Institute of Plasma Physics, Chinese Academy of Sciences for demonstration of the feasibility of a CICC based on Bi2212 round wire. One sub-size conductor cabled with 42 wires was designed, manufactured and tested with limited strand indentation during cabling and good transport performance. In this paper, the first test results and analysis on the AC loss of Bi2212 round wires and cabled conductor samples are presented. Furthermore, the impact of mechanical load on the AC loss of the sub-size conductor is investigated to represent the operation conditions with electromagnetic loads. The first tests provide an essential basis for the validation of Bi2212 CICC and its application in fusion magnets.

Ultrahigh vacuum STM/STS studies of the Bi-O surface in Bi2Sr2CuOy single crystals

International Nuclear Information System (INIS)

Ikeda, Kazuto; Tomeno, Izumi; Takamuku, Kenshi; Yamaguchi, Koji; Itti, Rittaporn; Koshizuka, Naoki

1992-01-01

Scanning tunneling microscopic and spectroscopic studies were made on cleaved surfaces of Bi 2 Sr 2 CuO y single crystals using an ultrahigh-vacuum scanning tunneling microscope (UHV-STM). The modulation structures of the Bi-O surface were observed at room temperature with atomic resolution. The tunneling spectra showed electronic gap structures similar to those observed for the Bi-O surface of superconducting Bi-2212 single crystals. This suggests that superconductivity is not directly related to the electronic structure observed in the Bi-O plane. (orig.)

Fabrication of bi-layer graphene and theoretical simulation for its possible application in thin film solar cell.

Science.gov (United States)

Behura, Sanjay K; Mahala, Pramila; Nayak, Sasmita; Yang, Qiaoqin; Mukhopadhyay, Indrajit; Janil, Omkar

2014-04-01

High quality graphene film is fabricated using mechanical exfoliation of highly-oriented pyrolytic graphite. The graphene films on glass substrates are characterized using field-emission scanning electron microscopy, atomic force microscopy, Raman spectroscopy, UV-vis spectroscopy and Fourier transform infrared spectroscopy. A very high intensity ratio of 2D to G-band (to approximately 1.67) and narrow 2D-band full-width at half maximum (to approximately 40 cm(-1)) correspond to the bi-layer graphene formation. The bi-layer graphene/p-GaN/n-InGaN/n-GaN/GaN/sAl2O3 system is studied theoretically using TCAD Silvaco software, in which the properties of exfoliated bi-layer graphene are used as transparent and conductive film, and the device exhibits an efficiency of 15.24% compared to 13.63% for ITO/p-GaN/n-InGaN/n-GaN/GaN/Al2O3 system.

Annealing-Induced Bi Bilayer on Bi2Te3 Investigated via Quasi-Particle-Interference Mapping.

Science.gov (United States)

Schouteden, Koen; Govaerts, Kirsten; Debehets, Jolien; Thupakula, Umamahesh; Chen, Taishi; Li, Zhe; Netsou, Asteriona; Song, Fengqi; Lamoen, Dirk; Van Haesendonck, Chris; Partoens, Bart; Park, Kyungwha

2016-09-27

Topological insulators (TIs) are renowned for their exotic topological surface states (TSSs) that reside in the top atomic layers, and hence, detailed knowledge of the surface top atomic layers is of utmost importance. Here we present the remarkable morphology changes of Bi2Te3 surfaces, which have been freshly cleaved in air, upon subsequent systematic annealing in ultrahigh vacuum and the resulting effects on the local and area-averaging electronic properties of the surface states, which are investigated by combining scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and Auger electron spectroscopy (AES) experiments with density functional theory (DFT) calculations. Our findings demonstrate that the annealing induces the formation of a Bi bilayer atop the Bi2Te3 surface. The adlayer results in n-type doping, and the atomic defects act as scattering centers of the TSS electrons. We also investigated the annealing-induced Bi bilayer surface on Bi2Te3 via voltage-dependent quasi-particle-interference (QPI) mapping of the surface local density of states and via comparison with the calculated constant-energy contours and QPI patterns. We observed closed hexagonal patterns in the Fourier transform of real-space QPI maps with secondary outer spikes. DFT calculations attribute these complex QPI patterns to the appearance of a "second" cone due to the surface charge transfer between the Bi bilayer and the Bi2Te3. Annealing in ultrahigh vacuum offers a facile route for tuning of the topological properties and may yield similar results for other topological materials.

Single crystal growth of high-temperature superconductor Bi2.1Sr1.9Ca1.0Cu2.0AlyOx

International Nuclear Information System (INIS)

Gu, G.D.; Lin, Z.W.

2000-01-01

The effect of Al doping on the crystal growth of Bi-2212 was studied by a floating zone method. The results show that the planar solid-liquid interface breaks down into a cellular growth front while increasing Al doping in the rods of Bi 2.1 Sr 1.9 Ca 1.0 Cu 2.0 Al y O x . The size of the single crystals decreases with the increase in Al doping. The solubility limit for Al or the maximum Cu-site substitution by Al in the Bi-2212 crystals is less than y = 0.01. The majority of nominal Al doping in the rods forms an Al-rich phase in the grain boundaries of the single crystals. The superconductivity of as-grown Al-doped crystals decreases progressively with increasing Al doping in the rods, however, the T c for annealed Al-doped crystals does not change with increasing Al doping in the rods. The unchanged T c for annealed Al-doped Bi-2212 crystals either suggests that a small amount of Al substitution in the Cu site does not cause T c to drop significantly, or indicates that Al only enters the Bi-2212 crystals as an impurity, but does not substitute at the Cu site in the Bi-2212 crystals. (author)

Piezoelectric properties of nonstoichiometric Sr1-xBi2+2x/3Ta2O9 ceramics

International Nuclear Information System (INIS)

Jain, Rajni; Chauhan, Arun Kumar Singh; Gupta, Vinay; Sreenivas, K.

2005-01-01

The effect of poling on the structural, dielectric, and piezoelectric properties has been investigated for sol-gel-derived strontium bismuth tantalate (SBT) [Sr 1-x Bi 2+2x/3 Ta 2 O 9 ] ceramics with x=0.0,0.15,0.30,0.45. The dielectric and ferroelectric properties are found to improve with increase in x up to 0.3. Beyond x>0.3 the properties are found to degrade due to the limited solid solubility and the presence of a mixed phase of bismuth tantalate (BiTaO 4 ) is detected with x=0.45. Poling treatment reduces the dielectric dispersion and dielectric loss in the frequency range (0.1-100 kHz). The resonance and antiresonance frequencies increase with increase in x (x=0-0.30), and the corresponding minimum impedance decreases. The measured coupling coefficients (k p ) are small (0.0967-0.1) for x=0-0.30, and the electromechanical quality factor (Q m =915) is a maximum for the Sr 0.7 Bi 2.2 Ta 2 O 9 composition (x=0.30). The estimated piezoelectric charge coefficient (d 31 ) and piezoelectric voltage coefficient (g 31 ) are 5.2 pC/N and 5.8x10 -3 V m/N, respectively. The positive values of d 31 and g 31 and the low dielectric permittivity of SBT yield a high value for the hydrostatic coefficients, despite the low charge coefficient of d 33 =24 pC/N. The maximum values of charge coefficient (d h =34 pC/N) and voltage coefficient (g h =39x10 -3 V m/N) are obtained for Sr 0.7 Bi 2.2 Ta 2 O 9 composition, and the estimated hydrostatic figure of merit (d h g h x10 -15 =1215 m 2 /N) is high

Phase relations and crystal structures in the systems (Bi,Ln)2WO6 and (Bi,Ln)2MoO6 (Ln=lanthanide)

International Nuclear Information System (INIS)

Berdonosov, Peter S.; Charkin, Dmitri O.; Knight, Kevin S.; Johnston, Karen E.; Goff, Richard J.; Dolgikh, Valeriy A.; Lightfoot, Philip

2006-01-01

Several outstanding aspects of phase behaviour in the systems (Bi,Ln) 2 WO 6 and (Bi,Ln) 2 MoO 6 (Ln=lanthanide) have been clarified. Detailed crystal structures, from Rietveld refinement of powder neutron diffraction data, are provided for Bi 1.8 La 0.2 WO 6 (L-Bi 2 WO 6 type) and BiLaWO 6 , BiNdWO 6 , Bi 0.7 Yb 1.3 WO 6 and Bi 0.7 Yb 1.3 WO 6 (all H-Bi 2 WO 6 type). Phase evolution within the solid solution Bi 2- x La x MoO 6 has been re-examined, and a crossover from γ(H)-Bi 2 MoO 6 type to γ-R 2 MoO 6 type is observed at x∼1.2. A preliminary X-ray Rietveld refinement of the line phase BiNdMoO 6 has confirmed the α-R 2 MoO 6 type structure, with a possible partial ordering of Bi/Nd over the three crystallographically distinct R sites. - Graphical abstract: A summary of phase relations in the lanthanide-doped bismuth tungstate and bismuth molybdate systems is presented, together with some additional structural data on several of these phases

Fuzzy Bi-level Decision-Making Techniques: A Survey

Directory of Open Access Journals (Sweden)

Guangquan Zhang

2016-04-01

Full Text Available Bi-level decision-making techniques aim to deal with decentralized management problems that feature interactive decision entities distributed throughout a bi-level hierarchy. A challenge in handling bi-level decision problems is that various uncertainties naturally appear in decision-making process. Significant efforts have been devoted that fuzzy set techniques can be used to effectively deal with uncertain issues in bi-level decision-making, known as fuzzy bi-level decision-making techniques, and researchers have successfully gained experience in this area. It is thus vital that an instructive review of current trends in this area should be conducted, not only of the theoretical research but also the practical developments. This paper systematically reviews up-to-date fuzzy bi-level decisionmaking techniques, including models, approaches, algorithms and systems. It also clusters related technique developments into four main categories: basic fuzzy bi-level decision-making, fuzzy bi-level decision-making with multiple optima, fuzzy random bi-level decision-making, and the applications of bi-level decision-making techniques in different domains. By providing state-of-the-art knowledge, this survey paper will directly support researchers and practitioners in their understanding of developments in theoretical research results and applications in relation to fuzzy bi-level decision-making techniques.

A plate-on-plate sandwiched Z-scheme heterojunction photocatalyst: BiOBr-Bi{sub 2}MoO{sub 6} with enhanced photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Wang, Shengyao [College of Science, Huazhong Agricultural University, Wuhan 430070 (China); Key Laboratory of Environment Correlative Dietology, Ministry of Education, Wuhan 430070 (China); Yang, Xianglong; Zhang, Xuehao; Ding, Xing; Yang, Zixin [College of Science, Huazhong Agricultural University, Wuhan 430070 (China); Dai, Ke [College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Chen, Hao, E-mail: hchenhao@mail.hzau.edu.cn [College of Science, Huazhong Agricultural University, Wuhan 430070 (China); Key Laboratory of Environment Correlative Dietology, Ministry of Education, Wuhan 430070 (China)

2017-01-01

Highlights: • A visible light heterojunction photocatalyst of BiOBr-Bi{sub 2}MoO{sub 6} was simply synthesized. • Carriers transferred efficiently in sandwiched layers causing an enhance activity. • A possible direct Z-scheme charge transfer mechanism of BiOBr-Bi2MoO6 is proposed. - Abstract: In this study, a direct Z-scheme heterojunction BiOBr-Bi{sub 2}MoO{sub 6} with greatly enhanced visible light photocatalytic performance was fabricated via a two-step coprecipitation method. It was indicated that a plate-on-plate heterojunctions be present between BiOBr and Bi{sub 2}MoO{sub 6} through different characterization techniques including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS) and photoelectrochemical measurements. The crystal structure and morphology analysis revealed that the heterointerface in BiOBr-Bi{sub 2}MoO{sub 6} occurred mainly on the (001) facets of BiOBr and (001) facets of Bi{sub 2}MoO{sub 6}. The photocatalytic activity of the BiOBr-Bi{sub 2}MoO{sub 6} was investigated by degradation of RhB and about 66.7% total organic carbon (TOC) could be removed. Ciprofloxacin (CIP) was employed to rule out the photosensitization. It was implied that the higher activity of BiOBr-Bi{sub 2}MoO{sub 6} could be attribute to the strong redox ability in the Z-scheme system, which was subsequently confirmed by photoluminescence spectroscopy (PL) and active spices trapping experiments. This study provides a promising platform for Z-scheme heterojunction constructing and also sheds light on highly efficient visible-light-driven photocatalysts designing.

DIALIGN: multiple DNA and protein sequence alignment at BiBiServ.

OpenAIRE

Morgenstern, Burkhard

2004-01-01

DIALIGN is a widely used software tool for multiple DNA and protein sequence alignment. The program combines local and global alignment features and can therefore be applied to sequence data that cannot be correctly aligned by more traditional approaches. DIALIGN is available online through Bielefeld Bioinformatics Server (BiBiServ). The downloadable version of the program offers several new program features. To compare the output of different alignment programs, we developed the program AltA...

[sup 205]Bi/[sup 206]Bi cyclotron production from Pb-isotopes for absorption studies in humans

Energy Technology Data Exchange (ETDEWEB)

Fischer, R.; Dresow, B.; Heinrich, H.C. (Universitaetskrankenhaus Eppendorf, Hamburg (Germany). Abt. Medizinische Biochemie); Wendel, J.; Bechtold, V. (Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Kernphysik)

1993-12-01

Pb(p,xn) thick target excitation functions were measured in the energy range 10-38 MeV in order to optimize the production of isotopically pure radiobismuth from [sup nat]Pb, [sup 206]Pb, and [sup 207]Pb. Additionally, the decay of Po-isotopes from deuteron irradiation of natural bismuth ([sup 209]Bi) was exploited for radiobismuth production. [sup 205]Bi was produced from [sup 206]Pb at 20 MeV with only 2% of [sup 206]Bi at 4 weeks post irradiation. Bismuth compounds as used in the treatment of peptic ulcer were labeled with [sup 205]Bi for absorption studies in animals and subjects. (Author).

Large power factor and anomalous Hall effect and their correlation with observed linear magneto resistance in Co-doped Bi2Se3 3D topological insulator

Science.gov (United States)

Singh, Rahul; Shukla, K. K.; Kumar, A.; Okram, G. S.; Singh, D.; Ganeshan, V.; Lakhani, Archana; Ghosh, A. K.; Chatterjee, Sandip

2016-09-01

Magnetoresistance (MR), thermo power, magnetization and Hall effect measurements have been performed on Co-doped Bi2Se3 topological insulators. The undoped sample shows that the maximum MR as a destructive interference due to a π-Berry phase leads to a decrease of MR. As the Co is doped, the linearity in MR is increased. The observed MR of Bi2Se3 can be explained with the classical model. The low temperature MR behavior of Co doped samples cannot be explained with the same model, but can be explained with the quantum linear MR model. Magnetization behavior indicates the establishment of ferromagnetic ordering with Co doping. Hall effect data also supports the establishment of ferromagnetic ordering in Co-doped Bi2Se3 samples by showing the anomalous Hall effect. Furthermore, when spectral weight suppression is insignificant, Bi2Se3 behaves as a dilute magnetic semiconductor. Moreover, the maximum power factor is observed when time reversal symmetry (TRS) is maintained. As the TRS is broken the power factor value is decreased, which indicates that with the rise of Dirac cone above the Fermi level the anomalous Hall effect and linearity in MR increase and the power factor decreases.

Development of a bi-directional standing wave linear piezoelectric actuator with four driving feet.

Science.gov (United States)

Liu, Yingxiang; Shi, Shengjun; Li, Chunhong; Chen, Weishan; Wang, Liang; Liu, Junkao

2018-03-01

A bi-directional standing wave linear piezoelectric ultrasonic actuator with four driving feet is proposed in this work. Two sandwich type transducers operated in longitudinal-bending hybrid modes are set parallelly. The working mode of the transducer is not simple hybrid vibrations of a longitudinal one and a bending one, but a special coupling vibration mode contained both longitudinal and bending components. Two transducers with the same structure and unsymmetrical boundary conditions are set parallelly to accomplish the bi-directional driving: the first transducer can push the runner forward, while the other one produces the backward driving. In the experiments, two voltages with different amplitudes are applied on the two transducers, respectively: the one with higher voltage serves as the actuator, whereas the other one applied with lower voltage is used to reduce the frictional force. The prototype achieves maximum no-load speed and thrust force of 244 mm/s and 9.8 N. This work gives a new idea for the construction of standing wave piezoelectric ultrasonic actuator with bi-directional driving ability. Copyright © 2017 Elsevier B.V. All rights reserved.

Fabrication and characterization of the p-type (Bi2Te3)x(Sb2Te3)1 ...

Indian Academy of Sciences (India)

electric materials in the composition range x = 0⋅2–0⋅3. (Yang et al 2000), but with improved thermoelectric properties, have been prepared by the zone melting method. The influence of Bi2Te3 content on thermoelectric properties was studied at room temperature. The results showed that the maximum figure of merit ...

Calorimetric investigation of Pb-Bi system

International Nuclear Information System (INIS)

Agarwal, Renu; Jat, Ram Avtar; Sen, B.K.

2008-01-01

Enthalpy increment of Pb 0.71 Bi 0.29 compound was determined using high temperature Calvet calorimeter. The data was fit into the following polynomial equation. ΔH(T-298.15 K) J/mol = -10384.96 + 39.23 T - 0.014T 2 - 18970/T. By precipitation method, the enthalpy of formation of the compound of composition Pb 0.68 Bi 0.32 at 448 K, from Pb(l) and Bi(l) was determined to be -2450± 50 J/mol and from Pb(s) and Bi(s) at 298.15 K was calculated to be 4047 J/mol. (author)

A New Technique of Removing Blind Spots to Optimize Wireless Coverage in Indoor Area

Directory of Open Access Journals (Sweden)

A. W. Reza

2013-01-01

Full Text Available Blind spots (or bad sampling points in indoor areas are the positions where no signal exists (or the signal is too weak and the existence of a receiver within the blind spot decelerates the performance of the communication system. Therefore, it is one of the fundamental requirements to eliminate the blind spots from the indoor area and obtain the maximum coverage while designing the wireless networks. In this regard, this paper combines ray-tracing (RT, genetic algorithm (GA, depth first search (DFS, and branch-and-bound method as a new technique that guarantees the removal of blind spots and subsequently determines the optimal wireless coverage using minimum number of transmitters. The proposed system outperforms the existing techniques in terms of algorithmic complexity and demonstrates that the computation time can be reduced as high as 99% and 75%, respectively, as compared to existing algorithms. Moreover, in terms of experimental analysis, the coverage prediction successfully reaches 99% and, thus, the proposed coverage model effectively guarantees the removal of blind spots.

A Novel Hybrid Actuator Driven Magnetically in the Bi-Cell PEM Fuel Cell Stack

Directory of Open Access Journals (Sweden)

Hsiaokang Ma

2017-10-01

Full Text Available This study develops an air breathing pump driven by a piezoelectric actuator for a proton exchange membrane fuel cell (PEMFC stack. Permanent magnets are combined with a piezoelectric actuator to drive three air breathing pumps using magnetic force. This design enables the pump to provide a sufficient amount of air simultaneously to six cathode flow field plates in a stack of three “bi-cell PZTmag–PEMFCs”. When both the PZTmag and the PDMSmag had a magnet with a 6-mm diameter and 1-mm thickness, a maximum amplitude of 87 μm was generated at 0.03 W of power under operating conditions of 70 Hz and 40 V. In computational fluid dynamics (CFD, when the nozzle and the diffuser of an air breathing pump have an aspect ratio of 13.13, air flow distributes uniformly inside the pump, thus allowing for uniform transmission of oxygen to the membrane electrode assembly. This aspect ratio was applied to the bi-cell PZTmag–PEMFC stack and yielded a maximum net power flux of 0.1925 W·cm−2, 20% higher than that reported in a previous study (Ma, 2013, with 68% and 76% less volume and weight, respectively.

X-ray standing wave study of the Bi/GaAs and Bi/GaP interfaces

International Nuclear Information System (INIS)

Herrera-Gomez, A.

1994-04-01

Interfaces are one of the most important elements determining the characteristics of electronic devices. Composite semiconductors, specifically the III-V family, are technologically attractive because of their mobility and optical properties, and also because they offer the possibility of engineering such properties as the size of the band gap. Nevertheless, Si has remained the most utilized semiconductor material, primarily because the fabrication of practical MOSFETs with III-V semiconductors remains elusive. Examples of such complex interfaces are the structures formed by one monolayer of Bi on the (110) surface of GaAs and GaP. While better matched Column V elements form epitaxial continuous monolayers on III-V semiconductor (110) surfaces, Bi is too large to accommodate on GaAs and GaP surfaces with long range order, and vacancies appear to allow relaxation. For the ideal systems, symmetry imposes the presence of only two nonequivalent adatom sites. However, for Bi/GaAs and Bi/GaP, more than two different sites are present because the position of Bi atoms next to a vacancy is not necessarily equivalent to that between other Bi atoms. The geometry of the Bi/GaAs and Bi/GaP systems was determined here by triangulating XSW results from three Bragg planes. A methodology was developed that provides an intrinsic check of the validity of assuming two sites for the overlayer structures. An experimental method was developed that allows the three reflections to be measured on the same sample, thus reducing the number of experimental variables, such as the degree of disorder. The traditional method of analysis was not accurate enough for this data, so a more reliable and faster method of data fitting was developed. A configuration used in the present work, which previously has been widely used, presents an intrinsic multireflection problem. This issue is discussed in depth, and the appropriate method is determined for analyzing the data obtained with this configuration

Dielectric and Energy Storage Properties of Ba0.65Sr0.35TiO3 Ceramics Modified by BiNbO4

Science.gov (United States)

Zheng, Yi; Zhang, Jihua; Wei, Meng; Dong, Xiangxiang; Huang, Jiapeng; Wu, Kaituo; Chen, Hongwei

2018-02-01

(1 - x) (Ba0.65Sr0.35TiO3)-xBiNbO4 (x = 0.0-0.15) ceramic were prepared by solid-state reaction method. The phase composition, microstructure, dielectric properties, polarization-electric field, breakdown strength and energy storage behaviors for the BiNbO4-modified Ba0.65Sr0.35TiO3 ceramics were investigated. With the addition of BiNbO4, the remnant polarization and saturation polarization decreased and the nonlinearity was suppressed. When x = 0.07, the maximum recoverable energy storage achieved was 0.5 J/cm3, 1.5 times that of un-doped Ba0.65Sr0.35TiO3 ceramics, with an efficiency of 96.89% and a breakdown electric field reaching 15.3 kV/mm. Therefore, BiNbO4 doping could improve the energy storage properties of Ba0.65Sr0.35TiO3 for high-energy pulse capacitor application.

Women's Health Insurance Coverage

Science.gov (United States)

... Women's Health Policy Women’s Health Insurance Coverage Women’s Health Insurance Coverage Published: Oct 31, 2017 Facebook Twitter LinkedIn ... that many women continue to face. Sources of Health Insurance Coverage Employer-Sponsored Insurance: Approximately 57.9 million ...

Uranium doping and neutron irradiation of Bi-2223 superconduction tapes for improved critical current density

International Nuclear Information System (INIS)

Moss, S.D.; Wang, W.G.; Dou, S.X.; Weinstein, R.

1998-01-01

It is demonstrated that a combination of neutron irradiation with uranium doping introduce fission tracks through a Bi-2223 tape which act as effective pinning centres, leading to a substantial increase in critical current. Preliminary data suggests that the combination of uranium doping and neutron irradiation produces improved flux pinning in Bi-2223 tapes over neutron irradiation alone. Before irradiation, SEM, DTA and XRD analyses were performed on the tapes. Both before and after irradiation the trapped maximum magnetic flux was measured at 77K. Before neutron irradiation, uranium doping has no effect on critical current. Preliminary SEM data suggested that the uranium is homogeneously distributed throughout the oxide core of the tape. The presence of 2212 and other secondary phases in the doped tapes suggest further refinement of the sintering procedure is necessary. (authors)

Rietveld refinement and dielectric properties of (Na{sub 0.5}Bi{sub 0.5}TiO{sub 3})-(Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3}) ceramics

Energy Technology Data Exchange (ETDEWEB)

Kaswan, Kavita, E-mail: kaswan.kavita@gmail.com; Agarwal, Ashish; Sanghi, Sujata; Singh, Ompal [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar-125001 (India)

2015-06-24

(1-x)(Na{sub 0.5}Bi{sub 0.5}TiO{sub 3})-x(Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3}) lead free ceramics (NBT, NBT-BBFO; x = 0.0, 0.1 respectively) have been synthesized by conventional solid state reaction method. Crystalline phase of sintered ceramics was investigated at room temperature using X-ray diffraction. Rietveld refinement of XRD data performed by FullProf revealed that both the samples exhibited rhombohedral structure with R3c space group. Dielectric properties of these ceramics were studied at different temperatures in a wide frequency range using impedance analyzer. Dielectric constant and dielectric loss were found to be increase with increase of BBFO content. The prepared ceramics exhibit a broad maximum in dielectric permittivity at 593K and dispersive permittivity at high temperatures. The NBT-BBFO sample shows a relaxor ferroelectric behavior at different frequencies.

Quantum interference effects in [Co/Bi]n thin films

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Athanasopoulos P.

2014-07-01

Full Text Available Magnetoconductivity (MC, Δσ(Β, and Hall coefficient, RH(B, measurements have been performed in polycrystalline thin films of Bi(15nm, Bi(10nm/Co(1nm/Bi(10nm trilayer and [Co(0.7nm/Bi(2nm]10 multilayer, grown by magnetron scattering. The temperature dependence of RH(B curves reveal the existence of a second conduction channel below 250K, that can be assigned to surface states. MC measurements between ±0.4T show at 5K an interplay between weak-antilocalization (WAL in Bi and Bi/Co/Bi films and weal-localization (WL in [Co/Bi]10 multilayer.

Surface kinetics of Bi4-xLaxTi3O12 films etched in a CF4/Ar gas chemistry

International Nuclear Information System (INIS)

Kim, Dong-Pyo; Kim, Kyoung-Tae; Efremov, A. M.; Kim, Chang-Il

2004-01-01

The surface reactions and the etch rate of Bi 4-x La x Ti 3 O 12 (BLT) films in a CF 4 /Ar plasma were investigated in an inductively coupled plasma (ICP) reactor in terms of the gas mixing ratio. The variation of relative volume densities for the F and the Ar atoms were measured with optical emission spectroscopy (OES). The maximum etch rate of 803 A/min was obtained in a CF 4 (20 %)/Ar(80 %) plasma. The presence of a maximum in the BLT etch rate at CF 4 (20 %)/Ar(80 %) may be explained by the concurrence of two etching mechanisms, physical sputtering and chemical reaction. Ar-ion bombardment played roles of destroying the metal (Bi, La, Ti)-O bonds and assisting the chemical reaction between metal and fluorine atoms. The chemical states of BLT were investigated using X-ray photoelectron spectroscopy (XPS), which confirmed the existence of nonvolatile etch byproducts (La-fluorides).

LTE-A cellular networks multi-hop relay for coverage, capacity and performance enhancement

CERN Document Server

Yahya, Abid

2017-01-01

In this book, three different methods are presented to enhance the capacity and coverage area in LTE-A cellular networks. The scope involves the evaluation of the effect of the RN location in terms of capacity and the determination of the optimum location of the relay that provides maximum achievable data rate for users with limited interference at the cell boundaries. This book presents a new model to enhance both capacity and coverage area in LTE-A cellular network by determining the optimum location for the RN with limited interference. The new model is designed to enhance the capacity of the relay link by employing two antennas in RN. This design enables the relay link to absorb more users at cell edge regions. An algorithm called the Balance Power Algorithm (BPA) is developed to reduce MR power consumption. The book pertains to postgraduate students and researchers in wireless & mobile communications. Provides a variety of methods for enhancing capacity and coverage in LTE-A cellular networks Develop...

Bi[NC5H3(CO2)2](OH2)xF (x=1 and 2): New one-dimensional Bi-coordination materials—Reversible hydration and topotactic decomposition to α-Bi2O3

International Nuclear Information System (INIS)

Jeon, Hye Rim; Lee, Dong Woo; Ok, Kang Min

2012-01-01

Two one-dimensional bismuth-coordination materials, Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 ) x F (x=1 and 2), have been synthesized by hydrothermal reactions using Bi 2 O 3 , 2,6-NC 5 H 3 (CO 2 H) 2 , HF, and water at 180 °C. Structures of the two materials were determined by single-crystal X-ray diffraction. Although they have different crystal structures, both Bi-organic materials shared a common structural motif, a one-dimensional chain structure consisting of Bi 3+ cations and pyridine dicarboxylate linkers. Detailed structural analyses include infrared spectroscopy, thermogravimetric analysis, and reversible hydration reactions for the coordinated water molecules were reported. Also, thermal decomposition of the rod-shaped Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 )F single crystals at 800 °C led to α-Bi 2 O 3 that maintained the same morphology of the original crystals. - Graphical abstract: Calcination of the Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 )F single crystals at 800 °C results in the α-Bi 2 O 3 rods that maintain the original morphology of the crystals. Highlights: ► Synthesis of one-dimensional chain Bi-organic frameworks. ► Reversible hydration reactions of Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 )F. ► Topotactic decomposition maintaining the same morphology of the original crystals.

Comparative analysis of the machine repair Problem with imperfect coverage and service pressure condition

Science.gov (United States)

Wang, Kuo-Hsiung; Liou, Cheng-Dar; Lin, Yu-Hsueh

2013-02-01

We analyze the warm-standby M/M/R machine repair problem with multiple imperfect coverage which involving the service pressure condition. When an operating machine (or warm standby) fails, it may be immediately detected, located, and replaced with a coverage probability c by a standby if one is available. A recursive method is used to develop the steady-state analytic solutions. The total expected profit function per unit time is derived to determine the joint optimal values at the maximum profit. We utilize the direct search method to measure the various characteristics of the profit function followed by Quasi-Newton method to search the optimal solutions.

Tunable, high-repetition-rate, dual-signal-wavelength femtosecond optical parametric oscillator based on BiB3O6

Science.gov (United States)

Meng, Xianghao; Wang, Zhaohua; Tian, Wenlong; Fang, Shaobo; Wei, Zhiyi

2018-01-01

We have demonstrated a high-repetition-rate tunable femtosecond dual-signal-wavelength optical parametric oscillator (OPO) based on BiB3O6 (BiBO) crystal, synchronously pumped by a frequency-doubled mode-locked Yb:KGW laser. The cavity is simple since no dispersion compensators are used in the cavity. The wavelength range of dual-signal is widely tunable from 710 to 1000 nm. Tuning is accomplished by rotating phase-matching angle of BiBO, and optimizing cavity length and output coupler. Using a 3.75 W pump laser, the maximum average dual-signal output power is 760 mW at 707 and 750 nm, leading to a conversion efficiency of 20.3% not taking into account the idler power. Our experimental results show a non-critical phase-matching configuration pumped by a high peak power laser source. The operation of the dual-signal benefits from the balance of phase matching and group velocity mismatching between the two signals.

Controlled hydrothermal synthesis of BiOxCly/BiOmIn composites exhibiting visible-light photocatalytic degradation of crystal violet

International Nuclear Information System (INIS)

Jiang, Yu-Rou; Lin, Ho-Pan; Chung, Wen-Hsin; Dai, Yong-Ming; Lin, Wan-Yu; Chen, Chiing-Chang

2015-01-01

Highlights: • This is the first report on a series of BiO x Cl y /BiO m I n heterojunctions. • The BiO x Cl y /BiO m I n composition was controlled by adjusting the growth parameters. • The BiO x Cl y /BiO m I n were indirect semiconductors with a 1.78–2.95-eV bandgap. • The new photocatalysts removed CV at a much faster rate than TiO 2 . • Mechanisms were determined by separating the intermediates using HPLC-MS. - Abstract: A series of BiO x Cl y /BiO m I n composites were prepared using autoclave hydrothermal methods. The composition and morphologies of the BiO x Cl y /BiO m I n composites were controlled by adjusting the experimental conditions: the reaction pH value, temperature, and KCl/KI molar ratio. The products were characterized using X-ray diffraction, scanning electron microscopy-electron dispersive X-ray spectroscopy, UV–vis diffuse reflectance spectroscopy, Brunauer–Emmett–Teller specific surface areas, cathodoluminescence, high-resolution transmission electron microscopy, and high-resolution X-ray photoelectron spectroscopy. The photocatalytic efficiencies of composite powder suspensions were evaluated by monitoring the crystal violet (CV) concentrations. In addition, the quenching effects of various scavengers indicated that the reactive O 2 · − played a major role, and OH· or h + played a minor role in CV degradation. The intermediates formed during the decomposition process were isolated, identified, and characterized using high performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry to elucidate the CV decomposition mechanism

Effect of Silver Doping on Transport Properties of Bi2Se3: AgxBi2Se3 and Bi2-xAgxSe3

Science.gov (United States)

Zhang, Min; Wei, Zhan-Tao

2018-03-01

Ag-doped Bi2Se3 with the formula AgxBi2Se3 and Bi2-xAgxSe3 were prepared and their electrical and magnetic transport properties have been investigated to study the influence of silver doping on transport properties of Bi2Se3 with different Ag-doped method. All samples exhibited metallic resistivity and the resistivity increased with increasing Ag concentration. The lattice parameter c of Ag-substituted and Ag-intercalated samples displays a contrary change as the Ag concentration increased. For the Ag-intercalated samples, both the resistance upturn were observed in the curves of temperature dependent of resistivity and temperature dependent of magnetoresistance, respectively, indicating that the enhanced surface effect was obtained in those samples. Monotonously, field-induced MR peaks around 200 K were also observed in those samples. Similar behaviors were not observed in the Ag-substituted samples.

Effect of Silver Doping on Transport Properties of Bi2Se3: AgxBi2Se3 and Bi2-xAgxSe3

Science.gov (United States)

Zhang, Min; Wei, Zhan-Tao

2018-05-01

Ag-doped Bi2Se3 with the formula AgxBi2Se3 and Bi2-xAgxSe3 were prepared and their electrical and magnetic transport properties have been investigated to study the influence of silver doping on transport properties of Bi2Se3 with different Ag-doped method. All samples exhibited metallic resistivity and the resistivity increased with increasing Ag concentration. The lattice parameter c of Ag-substituted and Ag-intercalated samples displays a contrary change as the Ag concentration increased. For the Ag-intercalated samples, both the resistance upturn were observed in the curves of temperature dependent of resistivity and temperature dependent of magnetoresistance, respectively, indicating that the enhanced surface effect was obtained in those samples. Monotonously, field-induced MR peaks around 200 K were also observed in those samples. Similar behaviors were not observed in the Ag-substituted samples.

Orientation and Temperature Dependence of Piezoelectric Properties for Sillenite-Type Bi12TiO20 and Bi12SiO20 Single Crystals

Directory of Open Access Journals (Sweden)

Chuanying Shen

2014-06-01

Full Text Available The full matrix of electro-elastic constants of sillenite-type crystals Bi12TiO20 (BTO and Bi12SiO20 (BSO were determined by the resonance method, with d14 and k14 being on the order of 40–48 pC/N and 31%–36%, respectively. In addition, double-rotated orientation dependence of d33 was investigated, with the maximum values of 25–28 pC/N being achieved in ZXtl45°/54°-cut samples. The electrical resistivity of BSO was found to be two orders higher than that of BTO, being on the order of 7 × 105 Ω cm at 500 °C. The temperature dependence of dielectric and piezoelectric properties were investigated. BSO exhibited a high thermal stability in the temperature range of 25–500 °C, while BTO showed a variation of ~3% in the range of 25–350 °C. The high values of d14 and k14, together with the good thermal stability, make BTO and BSO crystals potential candidates for electromechanical applications in medium temperature range.

Reduction in thermal conductivity of BiSbTe lump

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Kaleem [King Saud University, Sustainable Energy Technologies Center, College of Engineering, PO Box 800, Riyadh (Saudi Arabia); Wan, C. [Tsinghua University, State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Beijing (China); Al-Eshaikh, M.A.; Kadachi, A.N. [King Saud University, Research Center, College of Engineering, PO Box 800, Riyadh (Saudi Arabia)

2017-03-15

In this work, systematic investigations on the thermal conductivities of BiSbTe lump, microstructured pristine BiSbTe bulk and single wall carbon nanotubes (SWCNTs)/BiSbTe bulk nanocomposites were performed. BiSbTe lumps were crushed to form a coarse powder (200 μm) and effect of particle size reduction on the effective thermal conductivity of BiSbTe (200 μm) bulk were analyzed. For further reduction in the conductivity, a two pronged strategy has been employed. First, additional refinement of BiSbTe (200 μm) were performed through ball milling in an inert environment. Second, SWCNTs in 0.75, and 1.0 vol% were distributed uniformly in the fine BiSbTe ball milled powder. The results showed that the effective thermal conductivities decrease with the reduction in the particle size from lump to BiSbTe (200 μm) bulk as well as with the addition of SWCNTs accompanied by further refinement of BiSbTe particles. The significant reduction in thermal conductivities of the lump was achieved for pure BiSbTe (200 μm) bulk and 0.75 vol% of SWCNTs/BiSbTe composite. This can be ascribed to the enhanced phonon scattering by the grain boundaries between the nanostructured BiSbTe particles as well as the interfaces between BiSbTe and the low dimensional carbon nanotubes. (orig.)

Delimitation of homogeneous regions in the UNIFESP/EPM healthcare center coverage area based on sociodemographic indicators

Directory of Open Access Journals (Sweden)

Karina Yuri Harada

1999-01-01

Full Text Available CONTEXT: The drawing up of adequate Public Health action planning to address the true needs of the population would increase the chances of effectiveness and decrease unnecessary expenses. OBJECTIVE: To identify homogeneous regions in the UNIFESP/EPM healthcare center (HCC coverage area based on sociodemographic indicators and to relate them to causes of deaths in 1995. DESIGN: Secondary data analysis. SETTING: HCC coverage area; primary care. SAMPLE: Sociodemographic indicators were obtained from special tabulations of the Demographic Census of 1991. MAIN MEASURES: Proportion of children and elderly in the population; family providers’ education level (maximum: >15 years, minimum: 20 minimum wages, minimum: <1 minimum wage; proportional mortality distribution. RESULTS: The maximum income permitted the construction of four homogeneous regions, according to income ranking. Although the proportion of children and of elderly did not vary significantly among the regions, minimum income and education showed a statistically significant (p<0.05 difference between the first region (least affluent and the others. A clear trend of increasing maximum education was observed across the regions. Mortality also differed in the first region, with deaths generated by possibly preventable infections. CONCLUSION: The inequalities observed may contribute to primary health prevention.

Delimitation of homogeneous regions in the UNIFESP/EPM healthcare center coverage area based on sociodemographic indicators.

Science.gov (United States)

Harada, K Y; Silva, J G; Schenkman, S; Hayama, E T; Santos, F R; Prado, M C; Pontes, R H

1999-01-07

The drawing up of adequate Public Health action planning to address the true needs of the population would increase the chances of effectiveness and decrease unnecessary expenses. To identify homogeneous regions in the UNIFESP/EPM healthcare center (HCC) coverage area based on sociodemographic indicators and to relate them to causes of deaths in 1995. Secondary data analysis. HCC coverage area; primary care. Sociodemographic indicators were obtained from special tabulations of the Demographic Census of 1991. Proportion of children and elderly in the population; family providers' education level (maximum: > 15 years, minimum: 20 minimum wages, minimum: < 1 minimum wage); proportional mortality distribution The maximum income permitted the construction of four homogeneous regions, according to income ranking. Although the proportion of children and of elderly did not vary significantly among the regions, minimum income and education showed a statistically significant (p < 0.05) difference between the first region (least affluent) and the others. A clear trend of increasing maximum education was observed across the regions. Mortality also differed in the first region, with deaths generated by possibly preventable infections. The inequalities observed may contribute to primary health prevention.

The effect of oxidant on resputtering of Bi from Bi-Sr-Ca-Cu-O films

Science.gov (United States)

Grace, J. M.; McDonald, D. B.; Reiten, M. T.; Olson, J.; Kampwirth, R. T.; Gray, K. E.

1991-09-01

The type and partial pressure of oxidant mixed with argon can affect the selective resputtering of Bi in composite-target, magnetron-sputtered Bi-Sr-Ca-Cu-O films. Comparative studies using oxygen and ozone show that ozone is a more potent oxidant, as well as a more potent source of resputterers, than is oxygen. Severe resputtering from ozone is significantly reduced by a -40 V potential on the sample block. We suggest that oxygen causes resputtering by forming O2(+)p , which interacts with the target to produce energetic O(-). In contrast, ozone may form lower-energy O(-) by electron impact in the dark space. Negative oxygen ions from the target itself may be responsible for a background resputtering effect. Our results and those found for Y-Ba-Cu-O by others are comparable. Bi in Bi-Sr-Ca-Cu-O behaves as Ba in Y-Ba-Cu-O, with regard to selective resputtering; furthermore, the response of Sr, Ca, and Cu to oxygen in sputtered Bi-Sr-Ca-Cu-O is similar to what is observed for Cu in Y-Ba-Cu-O.

Facile synthesis of AgI/BiOI-Bi{sub 2}O{sub 3} multi-heterojunctions with high visible light activity for Cr(VI) reduction

Energy Technology Data Exchange (ETDEWEB)

Wang, Qi [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); The Brook Byer Institute for Sustainable Systems and School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332 (United States); Shi, Xiaodong; Liu, Enqin [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); Crittenden, John C. [The Brook Byer Institute for Sustainable Systems and School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332 (United States); Ma, Xiangjuan; Zhang, Yi [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); Cong, Yanqing, E-mail: yqcong@hotmail.com [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China)

2016-11-05

Graphical abstract: Highly visible-light-active AgI/BiOI-Bi{sub 2}O{sub 3} with multi-heterojunctions was developed. - Highlights: • Visible-light-active AgI/BiOI-Bi{sub 2}O{sub 3} with multi-heterojunctions was prepared. • Highly enhanced photocatalytic reduction of Cr(VI) was observed. • k{sub Cr(VI)} on AgI/BiOI-Bi{sub 2}O{sub 3} increased by ca.16 times relative to Bi{sub 2}O{sub 3}. • Decreased E{sub g}, shifted E{sub fb} and reduced charge transfer resistance were observed. • Simultaneous reduction of Cr(VI) and degradation of organics were achieved. - Abstract: AgI sensitized BiOI-Bi{sub 2}O{sub 3} composite (AgI/BiOI-Bi{sub 2}O{sub 3}) with multi-heterojunctions was prepared using simple etching-deposition process. Different characterization techniques were performed to investigate the structural, optical and electrical properties of the as-prepared photocatalysts. It was found that the ternary AgI/BiOI-Bi{sub 2}O{sub 3} composite exhibited: (1) improved photocurrent response, (2) smaller band gap, (3) greatly reduced charge transfer resistance and (4) negative shift of flat band potential, which finally led to easier generation and more efficient separation of photo-generated electron-hole pairs at the hetero-interfaces. Thus, for the reduction of Cr(VI), AgI/BiOI-Bi{sub 2}O{sub 3} exhibited excellent photocatalytic activity under visible light irradiation at near neutral pH. AgI/BiOI-Bi{sub 2}O{sub 3} was optimized when the initial molar ratio of KI to Bi{sub 2}O{sub 3} and AgNO{sub 3} to Bi{sub 2}O{sub 3} was 1:1 and 10%, respectively. The estimated k{sub Cr(VI)} on optimized AgI/BiOI-Bi{sub 2}O{sub 3} was about 16 times that on pure Bi{sub 2}O{sub 3}. Good stability was also observed in cyclic runs, indicating that the current multi-heterostructured photocatalyst is highly desirable for the remediation of Cr(VI)-containing wastewater.

Synthesis of activated charcoal supported Bi-doped TiO{sub 2} nanocomposite under solar light irradiation for enhanced photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Chandraboss, V.L.; Kamalakkannan, J.; Senthilvelan, S., E-mail: dr_senthilvel@yahoo.co.in

2016-11-30

Highlights: • Particle size and band gap of TiO{sub 2} is decreased upon Bi doping. • Methylene blue is successfully degraded over Bi/TiO{sub 2} and AC-Bi/TiO{sub 2}. • AC-Bi/TiO{sub 2} is more active photocatalyst than TiO{sub 2} and Bi/TiO{sub 2}. • AC-Bi/TiO{sub 2} led to a maximum extension of the spectral wavelength. • AC-Bi/TiO{sub 2} with enhanced photocatalytic activity produced much more reactive ·OH. - Abstract: In this study, activated charcoal (AC) supported bismuth (Bi)-doped Titanium dioxide (TiO{sub 2}) nanocomposite was synthesized by precipitation method. The photocatalytic activity of AC-Bi/TiO{sub 2} was investigated for the degradation of methylene blue (MB) in aqueous solution under solar light irradiation. The incorporation of Bi{sup 3+} into the TiO{sub 2} lattice shifts the absorbance of TiO{sub 2} to the visible region then the addition of high adsorption capacity activated charcoal to improve the efficiency of TiO{sub 2}. AC-Bi/TiO{sub 2} is found to be more efficient than Bi/TiO{sub 2} and undoped TiO{sub 2} for the degradation of MB under solar light irradiation. Surface morphology and bulk composition of the composite was obtained using high resolution-scanning electron microscopy with energy dispersive X-ray analysis. The crystal structure evolution and elemental composition were analyzed by combining Fourier transform-Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The ultraviolet-visible (UV–vis) absorption spectra show that the absorption edge for the composite with Bi{sup 3+} has red shift as compared with that of undoped TiO{sub 2}. UV–vis diffuse reflectance spectra demonstrated a decrease in the direct band gap of AC-Bi/TiO{sub 2}. BET surface area, pore radius and pore volume of the materials were calculated by applying the BET equation to the sorption isotherms. The production of hydroxyl radicals (·OH) on the surface of solar light irradiated materialswere detected by

In situ grown hierarchical 50%BiOCl/BiOI hollow flowerlike microspheres on reduced graphene oxide nanosheets for enhanced visible-light photocatalytic degradation of rhodamine B

Science.gov (United States)

Su, Xiangde; Yang, Jinjin; Yu, Xiang; Zhu, Yi; Zhang, Yuanming

2018-03-01

50%BiOCl/BiOI/reduced graphene oxide (50%BiOCl/BiOI/rGO) composite photocatalyst was synthesized successfully by a facile one-step solvothermal route in this work. Reduction of graphene oxide (GO) took place in the process of solvothermal reaction and a new Bi-C bond between rGO and 50%BiOCl/BiOI was formed. The introduction of rGO affected the morphology of 50%BiOCl/BiOI, resulting in the transformation of 50%BiOCl/BiOI from solid microspheres to hollow microspheres. Both the introduction of rGO and formation of 50%BiOCl/BiOI hollow microspheres can facilitate the light absorption. The strong interaction between 50%BiOCl/BiOI and rGO and the electrical conductivity of rGO greatly improved the effective separation of photogenerated carriers. Hence, GOB-5 demonstrated the highest photocatalytic activity which was over twice of the pristine 50%BiOCl/BiOI in the presence of visible light. Mechanism study revealed that 50%BiOCl/BiOI generated electrons and holes in the presence of visible light, and holes together with rad O2- generated from reduction of O2 by electrons degraded the pollutant directly. Overall, this work provides an excellent reference to the synthesis of chemically bonded BiOX/BiOY (X, Y = Cl, Br, I)/rGO nanocomposite and helps to promote their applications in environmental protection and photoelectric conversion.

alpha-decay spectroscopy of light odd-odd Bi isotopes - II sup 1 sup 8 sup 6 Bi and the new nuclide sup 1 sup 8 sup 4 Bi

CERN Document Server

Andreyev, A N; Ackermann, D; Münzenberg, G; Hessberger, F P; Hofmann, S; Kojouharov, I; Kindler, B; Lommel, B; Huyse, M; Vel, K V D; Duppen, P V; Heyde, Kris L G

2003-01-01

Alpha-decay of the new nuclide sup 1 sup 8 sup 4 Bi has been studied in the complete-fusion reaction sup 9 sup 3 Nb( sup 9 sup 4 Mo, 3n) sup 1 sup 8 sup 4 Bi at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of recoil-alpha, recoil-alpha-gamma analysis and excitation functions measurements. Two alpha-decaying isomeric states in sup 1 sup 8 sup 4 Bi with half-life values of 13(2) ms and 6.6(1.5) ms were identified. The alpha-branching ratio of sup 1 sup 8 sup 0 Tl was deduced for the first time as b subalpha = (2-12)%. Improved data on the fine-structure alpha-decay of sup 1 sup 8 sup 6 Bi were obtained in the sup 9 sup 3 Nb( sup 9 sup 5 Mo, 2n) sup 1 sup 8 sup 6 Bi reaction. A similarity of the decay energies and half-life values of sup 1 sup 8 sup 4 sup , sup 1 sup 8 sup 6 Bi is pointed out and a possible explanation for this effect is suggested.

Superstrengthening Bi2Te3 through Nanotwinning

Science.gov (United States)

Li, Guodong; Aydemir, Umut; Morozov, Sergey I.; Wood, Max; An, Qi; Zhai, Pengcheng; Zhang, Qingjie; Goddard, William A.; Snyder, G. Jeffrey

2017-08-01

Bismuth telluride (Bi2Te3 ) based thermoelectric (TE) materials have been commercialized successfully as solid-state power generators, but their low mechanical strength suggests that these materials may not be reliable for long-term use in TE devices. Here we use density functional theory to show that the ideal shear strength of Bi2Te3 can be significantly enhanced up to 215% by imposing nanoscale twins. We reveal that the origin of the low strength in single crystalline Bi2Te3 is the weak van der Waals interaction between the Te1 coupling two Te 1 - Bi - Te 2 - Bi - Te 1 five-layer quint substructures. However, we demonstrate here a surprising result that forming twin boundaries between the Te1 atoms of adjacent quints greatly strengthens the interaction between them, leading to a tripling of the ideal shear strength in nanotwinned Bi2Te3 (0.6 GPa) compared to that in the single crystalline material (0.19 GPa). This grain boundary engineering strategy opens a new pathway for designing robust Bi2Te3 TE semiconductors for high-performance TE devices.

Comparison of growth texture in round Bi2212 and flat Bi2223 wires and its relation to high critical current density development

OpenAIRE

Kametani, F.; Jiang, J.; Matras, M.; Abraimov, D.; Hellstrom, E. E.; Larbalestier, D. C.

2015-01-01

Why Bi2Sr2CaCu2Ox (Bi2212) allows high critical current density Jc in round wires rather than only in the anisotropic tape form demanded by all other high temperature superconductors is important for future magnet applications. Here we compare the local texture of state-of-the-art Bi2212 and Bi2223 ((Bi,Pb)2Sr2Ca2Cu3O10), finding that round wire Bi2212 generates a dominant a-axis growth texture that also enforces a local biaxial texture (FWHM

Improved safety and efficacy of 213Bi-DOTATATE-targeted alpha therapy of somatostatin receptor-expressing neuroendocrine tumors in mice pre-treated with L-lysine.

Science.gov (United States)

Chan, Ho Sze; Konijnenberg, Mark W; Daniels, Tamara; Nysus, Monique; Makvandi, Mehran; de Blois, Erik; Breeman, Wouter A; Atcher, Robert W; de Jong, Marion; Norenberg, Jeffrey P

2016-12-01

Targeted alpha therapy (TAT) offers advantages over current β-emitting conjugates for peptide receptor radionuclide therapy (PRRT) of neuroendocrine tumors. PRRT with 177 Lu-DOTATATE or 90 Y-DOTATOC has shown dose-limiting nephrotoxicity due to radiopeptide retention in the proximal tubules. Pharmacological protection can reduce renal uptake of radiopeptides, e.g., positively charged amino acids, to saturate in the proximal tubules, thereby enabling higher radioactivity to be safely administered. The aim of this preclinical study was to evaluate the therapeutic effect of 213 Bi-DOTATATE with and without renal protection using L-lysine in mice. Tumor uptake and kinetics as a function of injected mass of peptide (range 0.03-3 nmol) were investigated using 111 In-DOTATATE. These results allowed estimation of the mean radiation absorbed tumor dose for 213 Bi-DOTATATE. Pharmacokinetics and dosimetry of 213 Bi-DOTATATE was determined in mice, in combination with renal protection. A dose escalation study with 213 Bi-DOTATATE was performed to determine the maximum tolerated dose (MTD) with and without pre-administration of L-lysine as for renal protection. Neutrophil gelatinase-associated lipocalin (NGAL) served as renal biomarker to determine kidney injury. The maximum mean radiation absorbed tumor dose occurred at 0.03 nmol and the minimum at 3 nmol. Similar mean radiation absorbed tumor doses were determined for 0.1 and 0.3 nmol with a mean radiation absorbed dose of approximately 0.5 Gy/MBq 213 Bi-DOTATATE. The optimal mass of injected peptide was found to be 0.3 nmol. Tumor uptake was similar for 111 In-DOTATATE and 213 Bi-DOTATATE at 0.3 nmol peptide. Lysine reduced the renal uptake of 213 Bi-DOTATATE by 50% with no effect on the tumor uptake. The MTD was <13.0 ± 1.6 MBq in absence of L-lysine and 21.7 ± 1.9 MBq with L-lysine renal protection, both imparting an LD 50 mean renal radiation absorbed dose of 20 Gy. A correlation was found between the

Estudio de la región rica en Bi2O3 en el sistema binario ZnO-Bi2O3

Directory of Open Access Journals (Sweden)

Caballero, A. C.

2004-08-01

Full Text Available Ceramic materials based in the ZnO- Bi2O3 system have their principal application as varistors. The binary system ZnO-Bi2O3 is specially relevant to the formation of the microstructure responsable of the varistor behaviour. The study of the different equilibrium phases at high temperatures at the Bi2O3-rich region of the ZnO-Bi2O3 will allow a correct understanding of the microstructural development. Equilibrium phases have been analyzed by XRD, SEM and DTA. Different temperature treatments of samples formulated in the Bi2O3 rich region of the ZnO-Bi2O3 binary system have allowed to determine the phase 19Bi2O3•ZnO as the equilibrium one instead of the 24Bi2O3•ZnO phase.Los materiales cerámicos basados en el sistema binario ZnO-Bi2O3 tienen su principal aplicación en el campo de los varistores. El sistema binario ZnO-Bi2O3 resulta especialmente relevante para la formación de la microestructura funcional de varistores. La determinación de las diferentes fases en equilibrio a alta temperatura en la región rica en Bi2O3 en el sistema binario ZnO-Bi2O3 permitirá interpretar correctamente el desarrollo microestructural. El estudio de las fases en equilibrio se ha llevado a cabo mediante difracción de rayos X, microscopía electrónica de barrido (MEB y análisis térmico diferencial (ATD. Tratamientos a diferentes temperaturas, en la zona rica en Bi2O3 del sistema, han permitido determinar la presencia del compuesto 19Bi2O3•ZnO como fase estable en equilibrio, en lugar del compuesto 24Bi2O3•ZnO.

Shock compression behavior of bi-material powder composites with disparate melting temperatures

International Nuclear Information System (INIS)

Sullivan, Kyle T.; Swift, Damian; Barham, Matthew; Stölken, James; Kuntz, Joshua; Kumar, Mukul

2014-01-01

Laser driven experiments were used to investigate the shock compression behavior of powder processed Bismuth/Tungsten (Bi/W) composite samples. The constituents provide different functionality to the composite behavior as Bi could be shock melted at the pressures attained in this work, while the W could not. Samples were prepared by uniaxial pressing, and the relative density was measured as a function of particle size, applied pressure, and composition for both hot and cold pressing conditions. This resulted in sample densities between 73% and 99% of the theoretical maximum density, and also noticeable differences in microstructure in the hot and cold pressed samples. The compression waves were generated with a 1.3 × 1.3 mm square spot directly onto the surface of the sample, using irradiances between 10 12 and 10 13  W/cm 2 , which resulted in calculated peak pressures between 50 and 150 GPa within a few micrometers. Sample recovery and post-mortem analysis revealed the formation of a crater on the laser drive surface, and the depth of this crater corresponded to the depth to which the Bi had been melted. The melt depth was found to be primarily a function of residual porosity and composition, and ranged from 167 to 528 μm. In general, a higher porosity led to a larger melt depth. Direct numerical simulations were performed, and indicated that the observed increase in melt depth for low-porosity samples could be largely attributed to increased heating associated with work done for pore collapse. However, the relative scaling was sensitive to composition, with low volume fraction Bi samples exhibiting a much stronger dependence on porosity than high Bi content samples. Select samples were repeated using an Al foil ablator, but there were no noticeable differences ensuring that the observed melting was indeed pressure-driven and was not a result of direct laser heating. The resultant microstructures and damage near the spall surface were also investigated

Spatio-Temporal Change of Vegetation Coverage and its Driving Forces Based on Landsat Images: a Case Study of Changchun City

Science.gov (United States)

Dong, L.; Jiang, H.; Yang, L.

2018-04-01

Based on the Landsat images in 2006, 2011 and 2015, and the method of dimidiate pixel model, the Normalized Difference Vegetation Index (NDVI) and the vegetation coverage, this paper analyzes the spatio-temporal variation of vegetation coverage in Changchun, China from 2006 to 2015, and investigates the response of vegetation coverage change to natural and artificial factors. The research results show that in nearly 10 years, the vegetation coverage in Changchun dropped remarkably, and reached the minimum in 2011. Moreover, the decrease of maximum NDVI was significant, with a decrease of about 27.43 %, from 2006 to 2015. The vegetation coverage change in different regions of the research area was significantly different. Among them, the vegetation change in Changchun showed a little drop, and it decreased firstly and then increased slowly in Yushu, Nong'an and Dehui. In addition, the temperature and precipitation change, land reclamation all affect the vegetation coverage. In short, the study of vegetation coverage change contributes scientific and technical support to government and environmental protection department, so as to promote the coordinated development of ecology and economy.

TiO2/Bi2(BDC)3/BiOCl nanoparticles decorated ultrathin nanosheets with excellent photocatalytic reaction activity and selectivity

International Nuclear Information System (INIS)

Zhou, Shu-Mei; Ma, De-Kun; Cai, Ping; Chen, Wei; Huang, Shao-Ming

2014-01-01

Graphical abstract: TiO 2 /Bi 2 (BDC) 3 /BiOCl nanoparticles decorated ultrathin nanosheets showed excellent photocatalytic reaction activity and selectivity. - Highlights: • TiO 2 /Bi 2 (BDC) 3 /BiOCl nanoparticles decorated ultrathin nanosheets were synthesized through a facile hydrothermal process. • The products showed excellent photocatalytic activities for the degradation of various dyes. • The photocatalytic activities of the composite materials could be easily adjusted through tuning the content of TiO 2 . • TiO 2 /Bi 2 (BDC) 3 /BiOCl displayed obvious photocatalytic selectivity in mixed dyes systems of rhodamine B and eosin Y. - Abstract: Photocatalysts with excellent photocatalytic reaction activity and ideal selectivity are highly desirable for pollutants clearance and purification of targeted organics from a mixture. Continued efforts toward the goal, we here present a facile hydrothermal route to synthesize TiO 2 /Bi-benzenedicarboxylate/BiOCl nanoparticles decorated ultrathin nanosheets with a thickness less than 5 nm on a large scale. The as-synthesized products showed excellent photocatalytic activities for the degradation of various dyes such as rhodamine B, eosin Y and methylene blue in aqueous solution under visible light irradiation. The photocatalytic activities of TiO 2 /Bi-benzenedicarboxylate/BiOCl nanocomposites for the degradation of rhodamine B and eosin Y could be adjusted through tuning the content of TiO 2 . With increasing the amount of TiO 2 , the composites showed declining photocatalytic activities in decomposing of rhodamine B while on the contrary they displayed enhanced photocatalytic activities in decomposing of eosin Y. Interestingly, TiO 2 /Bi-benzenedicarboxylate/BiOCl composite nanosheets showed obvious photocatalytic selectivity in a mixed dyes system. The photocatalytic reaction and selectivity mechanisms of the nanocomposites for the degradation of the dyes were discussed on the basis of experimental results. The

Thermoelectric power of Bi and Bi{sub 1{minus}x}Sb{sub x} alloy thin films and superlattices grown by MBE

Energy Technology Data Exchange (ETDEWEB)

Cho, S; DiVenere, A; Wong, G K; Ketterson, J B; Meyer, J R; Hoffman, C A

1997-07-01

The authors have measured the thermoelectric power (TEP) of MBE-grown epitaxial Bi and Bi{sub 1{minus}x} alloy thin films and superlattices as a function of temperature in the range 20--300 K. They have observed that the TEP of a Bi thin film of 1 {micro}m thickness is in good agreement with the bulk single crystal value and that the TEPs for superlattices with 400 {angstrom} and 800 {angstrom} Bi well thicknesses are enhanced over the bulk values. For x = 0.072 and 0.088 in Bi{sub 1{minus}x}Sb{sub x} thin films showing semiconducting behavior, TEP enhancement was observed by a factor of two. However as Bi or Bi{sub 1{minus}x}Sb{sub x} well thickness decreases in superlattice geometry, the TEP decreases, which may be due to unintentional p-type doping.

Aurivillius-Popper mixed superconductors in BiO--CuO--(Sr/sub 0.5/, Ca/sub 0.5/)O system

International Nuclear Information System (INIS)

Fukuhara, M.; Bhalla, A.S.; Mulay, L.N.; Newnham, R.E.

1989-01-01

We report the effect of inhomogeneities on the electric resistivity and ac magnetic susceptibility in Aurivillius-like bismuth mixed phase oxides of the BiO--Cuo--(Sr/sub 0.5/, Ca/sub 0.5/)O system and propose a crystal structure of the major phase having highest T/sub c/. Nominal Aurivillius compositions with molar ratios of BiO/(Sr/sub 0.5/, Ca/sub 0.5/)O = 1/2 are superconductors with T/sub c/ ranging from 83 to 107 K, and are accompanied by a large expansion during sintering due to the formation of Kirkendall voids. T/sub c/ increases with decreasing of the c lattice parameter. An oxide BiSrCaCu 2 O/sub x/ (n = 2) shows a maximum T/sub c/ value of 107 K and an onset of superconductivity at a much higher temperature. It seems that the structure of Bi 2 Sr 2 CaCu 2 O/sub x/ consists of an Aurivillius-like phase having two perovskite layers and a Popper mixed phase. The ac magnetic susceptibility showed an overall decrease in susceptibility with time up to 220 days. This appears to be related to the relief of intralattice strain

BiP Negatively Affects Ricin Transport

Directory of Open Access Journals (Sweden)

Kirsten Sandvig

2013-05-01

Full Text Available The AB plant toxin ricin binds both glycoproteins and glycolipids at the cell surface via its B subunit. After binding, ricin is endocytosed and then transported retrogradely through the Golgi to the endoplasmic reticulum (ER. In the ER, the A subunit is retrotranslocated to the cytosol in a chaperone-dependent process, which is not fully explored. Recently two separate siRNA screens have demonstrated that ER chaperones have implications for ricin toxicity. ER associated degradation (ERAD involves translocation of misfolded proteins from ER to cytosol and it is conceivable that protein toxins exploit this pathway. The ER chaperone BiP is an important ER regulator and has been implicated in toxicity mediated by cholera and Shiga toxin. In this study, we have investigated the role of BiP in ricin translocation to the cytosol. We first show that overexpression of BiP inhibited ricin translocation and protected cells against the toxin. Furthermore, shRNA-mediated depletion of BiP enhanced toxin translocation resulting in increased cytotoxicity. BiP-dependent inhibition of ricin toxicity was independent of ER stress. Our findings suggest that in contrast to what was shown with the Shiga toxin, the presence of BiP does not facilitate, but rather inhibits the entry of ricin into the cytosol.

Low-temperature phase MnBi compound: A potential candidate for rare-earth free permanent magnets

International Nuclear Information System (INIS)

Ly, V.; Wu, X.; Smillie, L.; Shoji, T.; Kato, A.; Manabe, A.; Suzuki, K.

2014-01-01

Highlights: • The spin reorientation temperature of MnBi is suppressed by nanoscale grain refinement. • Hardness parameter of MnBi reaches as large as 2.8 at 580 K. • MnBi has a great potential as a hard phase in rare-earth free nanocomposite magnets. • Improving the surface passivity is a remaining task for MnBi-based permanent magnets. - Abstract: The low-temperature phase (LTP) MnBi is one of the few rare-earth free compounds that exhibit a large magnetocrystalline anisotropy energy in the order of 10 6 J/m 3 . A large coercive field (μ 0 H cj ) above 1 T can be obtained readily by reducing the crystallite size (D) through mechanical grinding (MG). The room-temperature H cj values follow a phenomenological expression μ 0 H cj = μ 0 H a (δ/D) n where the anisotropy field (μ 0 H a ) is ∼4 T, the Bloch wall width (δ) is 7 nm and the exponent (n) is about 0.7 in our study. The grain refinement upon MG is accompanied by suppression of the spin reorientation transition temperature (T SR ) from 110 K to below 50 K. The coercive field starts to exhibit positive temperature dependence approximately 50 K above T SR and the room-temperature magnetic hardening induced by MG could partially be brought about by the lowered onset of this positive temperature dependence. The suppression of T SR by MG is likely to be induced by the surface anisotropy with which the 2nd order crystal field term is enhanced. One of the shortcomings of LTP-MnBi is its poor phase stability under the ambient atmosphere. The spontaneous magnetization decreases considerably after room-temperature aging for 1 week. This is due to oxidation of Mn which leads to decomposition of the MnBi phase. Hence, the surface passivity needs to be established before this material is considered for a permanent magnet in practical uses. Another shortcoming is the limited spontaneous magnetization. The theoretical upper limit of the maximum energy product in LTP-MnBi remains only a quarter of that in Nd 2

Low-temperature phase MnBi compound: A potential candidate for rare-earth free permanent magnets

Energy Technology Data Exchange (ETDEWEB)

Ly, V.; Wu, X.; Smillie, L. [Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia); Shoji, T.; Kato, A.; Manabe, A. [Toyota Motor Corporation, Mishuku, Susono, Shizuoka 410-1193 (Japan); Suzuki, K., E-mail: kiyonori.suzuki@monash.edu [Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia)

2014-12-05

Highlights: • The spin reorientation temperature of MnBi is suppressed by nanoscale grain refinement. • Hardness parameter of MnBi reaches as large as 2.8 at 580 K. • MnBi has a great potential as a hard phase in rare-earth free nanocomposite magnets. • Improving the surface passivity is a remaining task for MnBi-based permanent magnets. - Abstract: The low-temperature phase (LTP) MnBi is one of the few rare-earth free compounds that exhibit a large magnetocrystalline anisotropy energy in the order of 10{sup 6} J/m{sup 3}. A large coercive field (μ{sub 0}H{sub cj}) above 1 T can be obtained readily by reducing the crystallite size (D) through mechanical grinding (MG). The room-temperature H{sub cj} values follow a phenomenological expression μ{sub 0}H{sub cj} = μ{sub 0}H{sub a}(δ/D){sup n} where the anisotropy field (μ{sub 0}H{sub a}) is ∼4 T, the Bloch wall width (δ) is 7 nm and the exponent (n) is about 0.7 in our study. The grain refinement upon MG is accompanied by suppression of the spin reorientation transition temperature (T{sub SR}) from 110 K to below 50 K. The coercive field starts to exhibit positive temperature dependence approximately 50 K above T{sub SR} and the room-temperature magnetic hardening induced by MG could partially be brought about by the lowered onset of this positive temperature dependence. The suppression of T{sub SR} by MG is likely to be induced by the surface anisotropy with which the 2nd order crystal field term is enhanced. One of the shortcomings of LTP-MnBi is its poor phase stability under the ambient atmosphere. The spontaneous magnetization decreases considerably after room-temperature aging for 1 week. This is due to oxidation of Mn which leads to decomposition of the MnBi phase. Hence, the surface passivity needs to be established before this material is considered for a permanent magnet in practical uses. Another shortcoming is the limited spontaneous magnetization. The theoretical upper limit of the maximum

Design of angle-resolved illumination optics using nonimaging bi-telecentricity for 193 nm scatterfield microscopy.

Science.gov (United States)

Sohn, Martin Y; Barnes, Bryan M; Silver, Richard M

2018-03-01

Accurate optics-based dimensional measurements of features sized well-below the diffraction limit require a thorough understanding of the illumination within the optical column and of the three-dimensional scattered fields that contain the information required for quantitative metrology. Scatterfield microscopy can pair simulations with angle-resolved tool characterization to improve agreement between the experiment and calculated libraries, yielding sub-nanometer parametric uncertainties. Optimized angle-resolved illumination requires bi-telecentric optics in which a telecentric sample plane defined by a Köhler illumination configuration and a telecentric conjugate back focal plane (CBFP) of the objective lens; scanning an aperture or an aperture source at the CBFP allows control of the illumination beam angle at the sample plane with minimal distortion. A bi-telecentric illumination optics have been designed enabling angle-resolved illumination for both aperture and source scanning modes while yielding low distortion and chief ray parallelism. The optimized design features a maximum chief ray angle at the CBFP of 0.002° and maximum wavefront deviations of less than 0.06 λ for angle-resolved illumination beams at the sample plane, holding promise for high quality angle-resolved illumination for improved measurements of deep-subwavelength structures using deep-ultraviolet light.

Optical spectroscopy and Fermi surface studies of BiTeCl and BiTeBr

Science.gov (United States)

Martin, Catalin; Suslov, A. V.; Buvaev, S.; Hebard, A. F.; Bugnon, Philippe; Berger, Helmuth; Magrez, Arnaud; Tanner, D. B.

2014-03-01

The observation of a large bulk Rashba effect in the non-centrosymmetric semiconductors BiTeX(X=Cl, Br, I) has stimulated the interest in these sys- tems, as promising candidates for studying spin related phenomena and for the realization of spin devices. Here we present a comparative study of the electronic properties of BiTeCl and BiTeBr, determined from temperature dependent infrared spectroscopy and Shubnikov-de Haas oscillations. In par- ticular, we compare the angle dependence of quantum oscillations between the two compounds and discuss possible differences between the topology of their Fermi surfaces. Supported by NSF Cooperative Agreement DMR-1157490 to the National High Magnetic Field Laboratory.

Exploring the high-pressure behavior of the three known polymorphs of BiPO4: Discovery of a new polymorph

International Nuclear Information System (INIS)

Errandonea, D.; García-Domene, B.; Gomis, O.; Santamaría-Perez, D.; Muñoz, A.; Rodríguez-Hernández, P.; Achary, S. N.; Tyagi, A. K.; Popescu, C.

2015-01-01

We have studied the structural behavior of bismuth phosphate under compression. We performed x-ray powder diffraction measurements up to 31.5 GPa and ab initio calculations. Experiments were carried out on different polymorphs: trigonal (phase I) and monoclinic (phases II and III). Phases I and III, at low pressure (P < 0.2–0.8 GPa), transform into phase II, which has a monazite-type structure. At room temperature, this polymorph is stable up to 31.5 GPa. Calculations support these findings and predict the occurrence of an additional transition from the monoclinic monazite-type to a tetragonal scheelite-type structure (phase IV). This transition was experimentally found after the simultaneous application of pressure (28 GPa) and temperature (1500 K), suggesting that at room temperature the transition might by hindered by kinetic barriers. Calculations also predict an additional phase transition at 52 GPa, which exceeds the maximum pressure achieved in the experiments. This transition is from phase IV to an orthorhombic barite-type structure (phase V). We also studied the axial and bulk compressibility of BiPO 4 . Room-temperature pressure-volume equations of state are reported. BiPO 4 was found to be more compressible than isomorphic rare-earth phosphates. The discovered phase IV was determined to be the less compressible polymorph of BiPO 4 . On the other hand, the theoretically predicted phase V has a bulk modulus comparable with that of monazite-type BiPO 4 . Finally, the isothermal compressibility tensor for the monazite-type structure is reported at 2.4 GPa showing that the direction of maximum compressibility is in the (0 1 0) plane at approximately 15° (21°) to the a axis for the case of our experimental (theoretical) study

Investigations on the Synthesis and Properties of Fe2O3/Bi2O2CO3 in the Photocatalytic and Fenton-like Process

Science.gov (United States)

Sun, Dongxue; Shen, Tingting; Sun, Jing; Wang, Chen; Wang, Xikui

2018-01-01

Catalyst of Bi2O2CO3 and Fe2O3 modified Bi2O2CO3 (Fe2O3/Bi2O2CO3) were prepared by hydrothermal method and characterized by X-ray diffractions (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and UV-vis DRS. The catalytic activity of Bi2O2CO3 and Fe2O3/Bi2O2CO3 were comparatively investigated in the photodegradation and Fento-like process. Rhodamine B(RhB) was selected as the target pollutant under the irradiation of 300 W xenon lamp. The results indicated that Fe2O3 plays a great role in the enhancing the treatment efficiency and the and the maximum reaction rate was achieved at the Fe2O3 loading of 1.5%. The Fenton-like degradation rate constant of RhB with bare Bi2O2CO3 in dark is 0.4 min-1, while that with 1.5 Fe2O3/Bi2O2CO3 increases to 28.4 min-1 under visible light irradiation, a 71-fold improvement. It is expected to shed a new light for the constructing novel composite photocatalyst and also provide a potential method for the removal of dyes in the aqueous system.

Carbon dioxide management by chemical conversion to methanol: HYDROGENATION and BI-REFORMING

International Nuclear Information System (INIS)

Wiesberg, Igor L.; Medeiros, José Luiz de; Alves, Rita M.B.; Coutinho, Paulo L.A.; Araújo, Ofélia Q.F.

2016-01-01

Highlights: • Evaluation of carbon dioxide conversion to methanol by two chemical routes. • HYDROGENATION: conversion via catalytic hydrogenation at high pressure. • BI-REFORMING: conversion via syngas from bi-reforming of natural gas. • HYDROGENATION is viable for hydrogen price inferior to 1000 US$/t. • BI-REFORMING is unable to avoid emissions; viable only if gas price is very low. - Abstract: Chemical conversion of carbon dioxide to methanol has the potential to address two relevant sustainability issues: economically feasible replacement of fossil raw materials and avoidance of greenhouse gas emissions. However, chemical stability of carbon dioxide is a challenging impediment to conversion requiring severe reaction conditions at the expense of increased energy input, therefore adding capital, operation and environmental costs, which could result in partial or total override of its potential sustainability as feedstock to the chemical and energy industries. This work investigates two innovative chemical destinations of carbon dioxide to methanol, namely a direct conversion through carbon dioxide hydrogenation (HYDROGENATION), and an indirect via carbon dioxide conversion to syngas through bi-reforming (BI-REFORMING). Process simulation is used to obtain mass and energy balances needed to support assessment of economic and environmental performance. A business scenario is considered where an industrial source of nearly pure carbon dioxide exists and an investment decision for utilization of carbon dioxide is faced. Due to uncertainties in prices of the raw materials, hydrogen (HYDROGENATION) and natural gas (BI-REFORMING), the decision procedure includes the definition of price thresholds to reach profitability. Sensitivity analyses are performed varying costs with greater uncertainty, i.e., carbon dioxide and methanol, and recalculating maximum allowable prices of raw materials. The analyses show that in a Brazilian scenario, BI-REFORMING is unlikely

Bi-cooperative games in bipolar fuzzy settings

Science.gov (United States)

Hazarika, Pankaj; Borkotokey, Surajit; Mesiar, Radko

2018-01-01

In this paper, we introduce the notion of a bi-cooperative game with Bipolar Fuzzy Bi-coalitions and discuss the related properties. In many decision-making situations, players show bipolar motives while cooperating among themselves. This is modelled in both crisp and fuzzy environments. Bi-cooperative games with fuzzy bi-coalitions have already been proposed under the product order of bi-coalitions where one had memberships in [0, 1]. In the present paper, we adopt the alternative ordering: ordering by monotonicity and account for players' memberships in ?, a break from the previous formulation. This simplifies the model to a great extent. The corresponding Shapley axioms are proposed. An explicit form of the Shapley value to a particular class of such games is also obtained. Our study is supplemented with an illustrative example.

Study of the tellurite-rich composition range in the Bi2O3-TeO2 system

International Nuclear Information System (INIS)

Ghazaryan, A.A.

2015-01-01

The TeO 2 and Bi 2 O 3 based glasses and glass ceramics are widely used for various technical needs. However, information about the phase diagram of the Bi 2 O 3 -TeO 2 system is limited, and the existing data are inconsistent. According to Demina L.A. with co-authors the Bi 2 Te 4 O 1 1 compound has a congruent melting at 662°C and forms two eutectics with neighbors. In another case, according to the Schmidt P. with co-authors, it melts incongruently at 645°C without indication of Liquidus temperature. It was the motivation for the Bi 2 Te 4 O 1 1 melting behavior investigation and the binary Bi 2 O 3 -TeO 2 system phase diagram correction in the TeO 2 rich area of compositions. As initial materials the glass and solid state sintered samples were used for these purposes. The differential thermal and X-ray analyses were used for glassy and crystallized products identification. The exothermic effect with maximum at 420°C and two endothermal effects with minimum at 635°C and 720 Degree C are clearly observed on the DTA curve of the 80 TeO 2 -20 Bi 2 O 3 (mol.percent) glass composition corresponding to the Bi 2 Te 4 O 1 1 compound. The product of Bi 2 Te 4 O 1 1 glass powder crystallization at 420°C is the Bi 2 Te 4 O 1 1 compound with melting point of 635 ± 5°C. The second endothermic effect on the DTA curve in the range of temperature 680-765°C with minimum at 720°C, is associated with dissolution of TeO 2 in the melt, formed as result of the Bi 2 Te 4 O 1 1 incongruent melting. The existence of eutectic E 1 (87 mol.percent TeO 2 ) between Bi 2 Te 4 O 1 1 and TeO 2 with a melting point of 580 ±5°C has been confirmed. Incongruent melting promotes the peritectic P 1 (81 mol.percent TeO 2 ) formation between Bi 2 Te 4 O 1 1 and eutectic E 1 (87 mol.percent TeO 2 ) with a melting point of 635±5°C. Three endothermic effects at 560 °C, 635 °C and 720°C have been observed on the DTA curve of Bi 2 Te 4 O 1 1 compound, obtained by solid state synthesis. Last

A Hybrid Maximum Power Point Tracking Method for Automobile Exhaust Thermoelectric Generator

Science.gov (United States)

Quan, Rui; Zhou, Wei; Yang, Guangyou; Quan, Shuhai

2017-05-01

To make full use of the maximum output power of automobile exhaust thermoelectric generator (AETEG) based on Bi2Te3 thermoelectric modules (TEMs), taking into account the advantages and disadvantages of existing maximum power point tracking methods, and according to the output characteristics of TEMs, a hybrid maximum power point tracking method combining perturb and observe (P&O) algorithm, quadratic interpolation and constant voltage tracking method was put forward in this paper. Firstly, it searched the maximum power point with P&O algorithms and a quadratic interpolation method, then, it forced the AETEG to work at its maximum power point with constant voltage tracking. A synchronous buck converter and controller were implemented in the electric bus of the AETEG applied in a military sports utility vehicle, and the whole system was modeled and simulated with a MATLAB/Simulink environment. Simulation results demonstrate that the maximum output power of the AETEG based on the proposed hybrid method is increased by about 3.0% and 3.7% compared with that using only the P&O algorithm and the quadratic interpolation method, respectively. The shorter tracking time is only 1.4 s, which is reduced by half compared with that of the P&O algorithm and quadratic interpolation method, respectively. The experimental results demonstrate that the tracked maximum power is approximately equal to the real value using the proposed hybrid method,and it can preferentially deal with the voltage fluctuation of the AETEG with only P&O algorithm, and resolve the issue that its working point can barely be adjusted only with constant voltage tracking when the operation conditions change.

Assessment of coverage levels of single dose measles vaccine

International Nuclear Information System (INIS)

Tariq, P.

2003-01-01

Objective: To study the consequences of low coverage levels of a single dose of measles vaccine. Results: mean age observed in measles cases was 2 years and 8 months with a range from 3 months to 8 years. Maximum number of cases reported were <1 year of age (n=22,32%). Fifty percent of cases were seen among vaccinated children. Seventy-five percent (n=51) had history of contact with a measles case. Pneumonia was the commonest complication followed by acute gastroenteritis, encephalitis, febrile convulsions, oral ulcers, oral thrush, eye changes of vitamin-A deficiency and pulmonary tuberculosis (T.B.) in descending order of frequency. Fifty four cases were successfully treated for complications of measles and discharged. Nine cases left against medical advice. Five patients died all of them had encephalitis either alone (n=1) or in combination with pneumonia and acute gastroenteritis (n=4). Conclusion: There is a dire need to increase the immunization coverage to reduce the rate of vaccine failure and achieve effective control of measles.(author)

Process controls for Bi2Te3-Sb2Te3 prepared by mechanical alloying and hot pressing

International Nuclear Information System (INIS)

Lee, Go-Eun; Kim, Il-Ho; Choi, Soon-Mok; Lim, Young-Soo; Seo, Won-Seon; Park, Jae-Soung; Yang, Seung-Ho

2014-01-01

p-Type Bi 2 Te 3 -Sb 2 Te 3 solid solutions were prepared by mechanical alloying (MA) and hot pressing (HP) under different process conditions, after which the transport and the thermoelectric properties were evaluated. The relative densities of all hot-pressed specimens were over 98%, and the microstructure and crystal orientation were independent of the HP direction. All specimens exhibited p-type conduction, and the electrical resistivity was observed to increase slightly with increasing temperature, indicating a degenerate semiconductor behavior. The carrier concentration decreased with increasing HP temperature while the mobility increased. The maximum figure of merit obtained was 0.86 at 323 K for Bi 0.5 Sb 1.5 Te 3 hot-pressed at 648 K.

Layer structured bismuth selenides Bi2Se3 and Bi3Se4 for high energy and flexible all-solid-state micro-supercapacitors

Science.gov (United States)

Hao, Chunxue; Wang, Lidan; Wen, Fusheng; Xiang, Jianyong; Li, Lei; Hu, Wentao; Liu, Zhongyuan

2018-02-01

In this work, bismuth selenides (Bi2Se3 and Bi3Se4), both of which have a layered rhombohedral crystal structure, have been found to be useful as electrode materials for supercapacitor applications. In a liquid electrolyte system (6M KOH), Bi2Se3 nanoplates exhibit much better performance as an electrode material than Bi3Se4 nanoparticles do, delivering a higher specific capacitance (272.9 F g-1) than that of Bi3Se4 (193.6 F g-1) at 5 mV s-1. This result may be attributed to the fact that Bi2Se3 nanoplates possess more active electrochemical surfaces for the reversible surface redox reactions owing to their planar quintuple stacked layers (septuple layers for Bi3Se4). To meet the demands of electronic skin, we used a novel flexible annular interdigital structure electrode to support the all-solid-state micro-supercapacitors (AMSCs). The Bi2Se3 AMSC device delivers a much better supercapacitor performance, exhibits a large stack capacitance of 89.5 F cm-3 at 20 mV s-1 (Bi3Se4: 79.1 F cm-3), a high energy density of 17.9 mWh cm-3 and a high power density of 18.9 W cm-3. The bismuth selenides also exhibit good cycle stability, with 95.5% retention after 1000 c for Bi2Se3 (Bi3Se4:90.3%). Clearly, Bi2Se3 nanoplates can be promising electrode materials for flexible annular interdigital AMSCs.

Enhanced photosensitization process induced by the p–n junction of Bi2O2CO3/BiOCl heterojunctions on the degradation of rhodamine B

International Nuclear Information System (INIS)

Lu, Haijing; Xu, Lingling; Wei, Bo; Zhang, Mingyi; Gao, Hong; Sun, Wenjun

2014-01-01

Herein, we report the enhanced photosensitization process in the nanosheet Bi 2 O 2 CO 3 /BiOCl heterojunctions photocatalyst. The combined XRD, FT-IR and Raman results have confirmed the co-existence of Bi 2 O 2 CO 3 and BiOCl phases in the composites. Although both Bi 2 O 2 CO 3 and BiOCl are wide bandgap semiconductors, the composites showed an unexpectedly high catalytic activity in decomposing RhB (rhodamine B) aqueous solution under visible light irradiation. The mechanism of enhanced photocatalytic activity was ascribed to the inner electric field formed in the Bi 2 O 2 CO 3 /BiOCl p–n junction.

High-temperature abnormal behavior of resistivities for Bi-In melts

International Nuclear Information System (INIS)

Xi Yun; Zu Fangqiu; Li Xianfen; Yu Jin; Liu Lanjun; Li Qiang; Chen Zhihao

2004-01-01

The patterns of electrical resistivities versus temperature in large temperature range have been studied, using the D.C. four-probe method, for liquid Bi-In alloys (Bi-In(33 wt%), Bi-In(38 wt%), Bi-In(50.5 wt%), Bi-In(66 wt%)). The clear turning point of each resistivity-temperature curves of the liquid Bi-In alloys is observed at the temperature much above the melting point, in which temperature range the resistivity-temperature coefficient increases rapidly. Except for the turning temperature range, the resistivities of Bi-In alloys increase linearly with temperature. Because resistivity is sensitive to the structure, this experiment shows the structural transition in Bi-In melts at the temperature much higher than the liquidus. And it is suggested that there are different Bi-In short-range orderings in different Bi-In melts, so the resistivity-temperature curves have the turns at different temperatures and the resistivity-temperature coefficients are also different

Influence of Ga-doping on the thermoelectric properties of Bi(2−xGaxTe2.7Se0.3 alloy

Directory of Open Access Journals (Sweden)

Xingkai Duan

2015-02-01

Full Text Available Bi(2−xGaxTe2.7Se0.3 (x=0, 0.04, 0.08, 0.12 alloys were fabricated by vacuum melting and hot pressing technique. The structure of the samples was evaluated by means of X-ray diffraction. The peak shift toward higher angle can be observed by Ga-doping. The effects of Ga substitution for Bi on the electrical and thermal transport properties were investigated in the temperature range of 300–500 K. The power factor values of the Ga-doped samples are obviously improved in the temperature range of 300–440 K. Among all the samples, the Bi(2−xGaxTe2.7Se0.3 (x=0.04 sample showed the lowest thermal conductivity near room temperature and the maximum ZT value reached 0.82 at 400 K.

High-pressure studies of superconductivity in BiO0. 75F0. 25BiS2

Indian Academy of Sciences (India)

). We have investigated the effect of pressure on magnetization measurements. Our studies suggest improved superconducting properties in polycrystalline samples of BiO 0.75 F 0.25 BiS 2 . The Tc in our sample is 5.3 K, at ambient pressure, ...

Potential barrier behavior in BiCuVOX materials Comportamento da barreira de potencial em materiais BiCuVOX

Directory of Open Access Journals (Sweden)

S. M. Gheno

2011-12-01

Full Text Available The BiMeVOX materials appear being high attractive for applications at low temperatures when the ionic conductivity is the determining parameter. The occurrence of many types substitution was confirmed for numerous Me ions, but the greatest interest have been focused on the BiCuVOX materials. The objective of this study was to image the potential barriers in BiCuVOX. The sample was sintered for 4 h at 750 °C and the results show that the high density compound can be obtained. Simultaneously, topography and electric force microscopy (EFM images are viewed side-by-side. EFM experiments were performed and the results show the maps of the electric field distribution on the surface of BiCuVOX. The formation of potential barrier was observed and the width and intensity were measured.Materiais do tipo BiMeVOX são muito atrativos para aplicações em baixas temperaturas quando a condutividade iônica for o parâmetro determinante. A ocorrência de muitos tipos de substituições foi confirmada para numerosos íons Me, dentre os quais, existe um grande interesse no estudo de materiais BiCuVOX. O objetivo deste estudo foi realizar o imageamento das barreiras de potencial em uma amostra de material BiCuVOX. A amostra foi sinterizada 4 h a 750 °C e apresentou alta densidade. Imagens da superfície topográfica e de microscopia de força elétrica (EFM foram obtidas simultaneamente em um microscópio de varredura por sonda. Os experimentos EFM mostraram um mapa da distribuição do campo elétrico na superfície do material BiCuVOx. A formação da barreira de potencial foi observada e tanto a largura quanto a altura foram medidas.

Thermoelectric properties of n-type Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} fabricated by mechanical alloying and hot pressing

Energy Technology Data Exchange (ETDEWEB)

Kim, H J; Choi, J S; Oh, T S; Hyun, D B

1997-07-01

Thermoelectric properties of polycrystalline Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} (0.05 {le} x {le} 0.25), fabricated by mechanical alloying and hot pressing, have been investigated. Formation of n-type Bi{sub 2}(Te{sub 0.9}Se{sub 0.1}){sub 3} alloy powders was completed by mechanical alloying for 3 hours at ball-to-material ratio of 5:1, and processing time for Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} formation increased with Bi{sub 2}Se{sub 3} content x. Figure-of-merit of Bi{sub 2}(Te{sub 0.9}Se{sub 0.1}) was markedly increased by hot pressing at temperatures above 450 C, and maximum value of 1.9 x 10{sup {minus}3}/K was obtained by hot pressing at 550 C. With addition of 0.015 wt% Bi as acceptor dopant, figure-of-merit of Bi{sub 2}(Te{sub 0.9}Se{sub 0.1}){sub 3} was hot pressed at 550 C, could be improved to 2.1 x 10{sup {minus}3}/K. When Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} was hot pressed at 550 C, figure-of-merit increased from 1.14 x 10{sup {minus}3}/K to 1.92 x 10{sup {minus}3}/K with increasing Bi{sub 2}Se{sub 3} content x from 0.05 to 0.15, and then decreased to 1.30 x 10{sup {minus}3}/K for x = 0.25 composition.

Gd-substituted Bi-2223 superconductor

Indian Academy of Sciences (India)

The effects of gadolinium doping at calcium site on the normal and super- conducting properties of Bi-2223 system were ... quantities of the metal oxides and the carbonates were taken and thoroughly mixed. The calcination of the mixture after .... Therefore, Gd has higher solubility in (BiPb)-2223 as compared to Pr, and is, ...

Bi[NC5H3(CO2)2](OH2)xF (x=1 and 2): New one-dimensional Bi-coordination materials—Reversible hydration and topotactic decomposition to α-Bi2O3

Science.gov (United States)

Jeon, Hye Rim; Lee, Dong Woo; Ok, Kang Min

2012-03-01

Two one-dimensional bismuth-coordination materials, Bi[NC5H3(CO2)2](OH2)xF (x=1 and 2), have been synthesized by hydrothermal reactions using Bi2O3, 2,6-NC5H3(CO2H)2, HF, and water at 180 °C. Structures of the two materials were determined by single-crystal X-ray diffraction. Although they have different crystal structures, both Bi-organic materials shared a common structural motif, a one-dimensional chain structure consisting of Bi3+ cations and pyridine dicarboxylate linkers. Detailed structural analyses include infrared spectroscopy, thermogravimetric analysis, and reversible hydration reactions for the coordinated water molecules were reported. Also, thermal decomposition of the rod-shaped Bi[NC5H3(CO2)2](OH2)F single crystals at 800 °C led to α-Bi2O3 that maintained the same morphology of the original crystals.

Calcium-doping effects on photovoltaic response and structure in multiferroic BiFeO{sub 3} ceramics

Energy Technology Data Exchange (ETDEWEB)

Tu, C. S. [Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China); Department of Physics, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China); Hung, C.-M.; Anthoninappen, J. [Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China); Xu, Z.-R.; Ting, Y.; Peng, Y.-T. [Department of Physics, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China); Schmidt, V. H.; Chien, R. R. [Department of Physics, Montana State University, Bozeman, Montana 59717 (United States)

2013-09-28

Photovoltaic (PV) effects, power-conversion efficiencies, and structures have been systematically measured in (Bi{sub 1−x}Ca{sub x})FeO{sub 3−δ} ceramics for x = 0.05, 0.10, and 0.15. The heterostructures of indium tin oxide (ITO) film/(Bi{sub 1−x}Ca{sub x})FeO{sub 3−δ} ceramics/Au film exhibit significant PV effects under illumination of λ = 405 nm. The maximum power-conversion efficiency in the ITO/(Bi{sub 0.90}Ca{sub 0.10})FeO{sub 2.95} (BFO10C)/Au can reach 0.0072%, which is larger than 0.0025% observed in the graphene/polycrystalline BFO/Pt films [Zang et al., Appl. Phys. Lett. 99, 132904 (2011)]. A theoretical model based on optically excited current in the depletion region between ITO film and Ca-doped BFO ceramics is used to describe the I-V characteristic, open-circuit voltage, and short-circuit current density as a function of illumination intensity. This work suggests that the Ca-substitution can reduce the rhombohedral distortion and stabilize the single-phase structure.

Magneto-optical properties BaBi{sub x}La{sub x}Fe{sub 12−2x}O{sub 19} (0.0≤x≤0.5) hexaferrites

Energy Technology Data Exchange (ETDEWEB)

Auwal, I.A. [Department of Chemistry, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Baykal, A., E-mail: hbaykal@fatih.edu.tr [Department of Chemistry, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Güner, S. [Department of Physics, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Sertkol, M. [Department of Physics Engineering, Istanbul Technical University, 34469 Maslak, Istanbul (Turkey); Sözeri, H. [TUBITAK-UME, National Metrology Institute, P.O. Box 54, 41470 Gebze, Kocaeli (Turkey)

2016-07-01

BaBi{sub x}La{sub x}Fe{sub (12−2x)}O{sub 19} (0.0≤x≤0.5) hexaferrites were synthesized by solid state synthesis route and the effects of Bi, La substitutions on structural, magnetic and optical properties were investigated. X-ray powder diffraction, Scanning electron microscopy, Vibrating sample magnetometer, and Percent diffuse reflectance spectroscopy were used to study the physical properties. Room temperature specific magnetization (M–H) curves revealed the ferromagnetic nature of all products. The increasing Bi, La compositions increased the magnetic properties at different magnitudes with respect to undoped BaFe{sub 12}O{sub 19} sample. The maximum values of remnant specific magnetization (M{sub r}=30.3 emu/g), extrapolated specific saturation magnetization (M{sub s}=62.12 emu/g), and magneton number (n{sub B}=16.27) were recorded from BaBi{sub 0.2}La{sub 0.2}Fe{sub 11.4}O{sub 19} hexaferrite. The average crystallite size varies in a range of (37.35–51.36) nm. The coercive field (H{sub c}) of undoped hexaferrites is 1180 Oe and increased to maximum 2320 Oe belonging to BaBi{sub 0.4}La{sub 0.4}Fe{sub 11.2}O{sub 19}. Magnetic anisotropy was confirmed as uniaxial and calculated effective anisotropy constants (K{sub eff}) are between 4.27×10{sup 5} Ergs/g and 5.05×10{sup 5} Ergs/g. The high magnitudes of magnetocrystalline anisotropy (H{sub a}) above than 16,200 Oe revealed that all samples are magnetically hard materials. The Tauc plots were drawn to extrapolate the direct optical energy band gap (E{sub g}) of hexaferrites. The E{sub g} values decreased from 1.76 eV to 1.47 eV with increasing Bi, La compositions. - Highlights: • BaBi{sub x}La{sub x}Fe{sub (12−2x)}O{sub 19} (0.0≤x≤0.5) hexaferrites were synthesized by solid state synthesis route. • The E{sub g} values decreased from 1.76 eV to 1.47 eV with increasing Bi, La compositions. • BaBi{sub xx}La{sub xx}Fe{sub 12-2x}O{sub 19} hexaferrites good candidate for potential applications

Electron diffraction study of the sillenites Bi12SiO20, Bi25FeO39 and Bi25InO39: Evidence of short-range ordering of oxygen-vacancies in the trivalent sillenites

Directory of Open Access Journals (Sweden)

Craig A. Scurti

2014-08-01

Full Text Available We present an electron diffraction study of three sillenites, Bi12SiO20, Bi25FeO39, and Bi25InO39 synthesized using the solid-state method. We explore a hypothesis, inspired by optical studies in the literature, that suggests that trivalent sillenites have additional disorder not present in the tetravalent compounds. Electron diffraction patterns of Bi25FeO39 and Bi25InO39 show streaks that confirm deviations from the ideal sillenite structure. Multi-slice simulations of electron-diffraction patterns are presented for different perturbations to the sillenite structure - partial substitution of the M site by Bi3+, random and ordered oxygen-vacancies, and a frozen-phonon model. Although comparison of experimental data to simulations cannot be conclusive, we consider the streaks as evidence of short-range ordered oxygen-vacancies.

The effect of FR enhancement in reactive ion beam sputtered Bi, Gd, Al-substituted iron- garnets: Bi2O3 nanocomposite films

OpenAIRE

Berzhansky, V.; Shaposhnikov, A.; Karavainikov, A.; Prokopov, A.; Mikhailova, T.; Lukienko, I.; Kharchenko, Yu.; Miloslavskaya, O.; Kharchenko, N.

2012-01-01

The effect of considerable Faraday rotation (FR) and figure of merit (Q) enhancement in Bi, Gd, Al-substituted iron garnets: Bi2O3 nano-composite films produced by separate reactive ion beam sputtered Bi:YIG and Bi2O3 films was found. It reached threefold enhancement of the FR and twofold of the Q one on GGG substrates.

Facile large scale synthesis of Bi{sub 2}S{sub 3} nano rods–graphene composite for photocatalytic photoelectrochemical and supercapacitor application

Energy Technology Data Exchange (ETDEWEB)

Vadivel, S. [Electrochemical Engineering Laboratory, Department of Chemical Engineering, C. Tech Campus, Anna University, Chennai-600 025 (India); Naveen, A. Nirmalesh [Department of Physics, Anna University, Chennai, Tamil Nadu 600025 (India); Kamalakannan, V.P. [Electrochemical Engineering Laboratory, Department of Chemical Engineering, C. Tech Campus, Anna University, Chennai-600 025 (India); Cao, P. [Department of Chemistry and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand); Balasubramanian, N., E-mail: nbsbala@annauniv.edu [Electrochemical Engineering Laboratory, Department of Chemical Engineering, C. Tech Campus, Anna University, Chennai-600 025 (India)

2015-10-01

Graphical abstract: - Highlights: • A Bi{sub 2}S{sub 3}/RGO composite was synthesized by one pot precipitation method. • The synthesized Bi{sub 2}S{sub 3}/RGO composite exhibit rod like morphology. • As synthesized composite was applied for malachite green degradation. • The synthesized Bi{sub 2}S{sub 3}/RGO composite exhibits a specific capacitance of 290 F g{sup −1} at a scan rate of 1 A g{sup −1}. • Photocatalytic and supercapacitor properties of Bi{sub 2}S{sub 3} were enhanced mainly due to effective graphene incorporation. - Abstract: Bi{sub 2}S{sub 3} nano rods–graphene (BG) composite material was synthesized by a simple one step precipitation method. The crystallanity, structural and morphological properties were studied by the X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy techniques. The photocatalytic activity of BG was evaluated by the photocatalytic degradation of malachite green dye (MG) aqueous solution under the visible light irradiation. The effect of graphene content on the photoelectrochemical property of Bi{sub 2}S{sub 3} nano rods was also studied. The enhancement of photocurrent and photocatalytic properties of BG composite attributed to the synergistic effect between the Bi{sub 2}S{sub 3} nano rods and graphene sheets which improves the charge separation efficiency in Bi{sub 2}S{sub 3} nano rods. The supercapacitor behavior was studied using cyclic voltametry and galvanostatic charge discharge studies. The BG composite exhibits a maximum specific capacitance of 290 F g{sup −1} at a current density of 1 A g{sup −1}. The present study may provide as a new approach in improving the performance of BG composite in supercapacitor, solar cells and photocatalytic applications.

Overexpression of BiP in tobacco alleviates endoplasmic reticulum stress

NARCIS (Netherlands)

Leborgne-Castel, N.; Jelitto- Dooren, E.P.W.M. van; Crofts, A.J.; Denecke, J.

1999-01-01

To study the role of the lumenal binding protein (BiP) in the transport and secretion of proteins, we have produced plants with altered BiP levels. Transgenic plants overexpressing BiP showed dramatically increased BiP mRNA levels but only a modest increase in BiP protein levels. The presence of

Bi-amalgamations subject to the arithmetical property

OpenAIRE

Kabbaj, S.; Mahdou, N.; Moutui, M. A. S.

2016-01-01

This paper establishes necessary and sufficient conditions for a bi-amalgamation to inherit the arithmetical property, with applications on the weak global dimension and transfer of the semihereditary property. The new results compare to previous works carried on various settings of duplications and amalgamations, and capitalize on recent results on bi-amalgamations. All results are backed with new and illustrative examples arising as bi-amalgamations.

BiOCl nanowire with hierarchical structure and its Raman features

International Nuclear Information System (INIS)

Tian Ye; Guo Chuanfei; Guo Yanjun; Wang Qi; Liu Qian

2012-01-01

BiOCl is a promising V-VI-VII-compound semiconductor with excellent optical and electrical properties, and has great potential applications in photo-catalysis, photoelectric, etc. We successfully synthesize BiOCl nanowire with a hierarchical structure by combining wet etch (top-down) with liquid phase crystal growth (bottom-up) process, opening a novel method to construct ordered bismuth-based nanostructures. The morphology and lattice structures of Bi nanowires, β-Bi 2 O 3 nanowires and BiOCl nanowires with the hierarchical structure are investigated by scanning electron microscope (SEM) and transition electron microscope (TEM). The formation mechanism of such ordered BiOCl hierarchical structure is considered to mainly originate from the highly preferred growth, which is governed by the lattice match between (1 1 0) facet of BiOCl and (2 2 0) or (0 0 2) facet of β-Bi 2 O 3 . A schematic model is also illustrated to depict the formation process of the ordered BiOCl hierarchical structure. In addition, Raman properties of the BiOCl nanowire with the hierarchical structure are investigated deeply.

The maximum economic depth of groundwater abstraction for irrigation

Science.gov (United States)

Bierkens, M. F.; Van Beek, L. P.; de Graaf, I. E. M.; Gleeson, T. P.

2017-12-01

Over recent decades, groundwater has become increasingly important for agriculture. Irrigation accounts for 40% of the global food production and its importance is expected to grow further in the near future. Already, about 70% of the globally abstracted water is used for irrigation, and nearly half of that is pumped groundwater. In many irrigated areas where groundwater is the primary source of irrigation water, groundwater abstraction is larger than recharge and we see massive groundwater head decline in these areas. An important question then is: to what maximum depth can groundwater be pumped for it to be still economically recoverable? The objective of this study is therefore to create a global map of the maximum depth of economically recoverable groundwater when used for irrigation. The maximum economic depth is the maximum depth at which revenues are still larger than pumping costs or the maximum depth at which initial investments become too large compared to yearly revenues. To this end we set up a simple economic model where costs of well drilling and the energy costs of pumping, which are a function of well depth and static head depth respectively, are compared with the revenues obtained for the irrigated crops. Parameters for the cost sub-model are obtained from several US-based studies and applied to other countries based on GDP/capita as an index of labour costs. The revenue sub-model is based on gross irrigation water demand calculated with a global hydrological and water resources model, areal coverage of crop types from MIRCA2000 and FAO-based statistics on crop yield and market price. We applied our method to irrigated areas in the world overlying productive aquifers. Estimated maximum economic depths range between 50 and 500 m. Most important factors explaining the maximum economic depth are the dominant crop type in the area and whether or not initial investments in well infrastructure are limiting. In subsequent research, our estimates of

Layer Structured Bismuth Selenides of Bi2Se3 and Bi3Se4 for High Energy and Flexible All-Solid-State Micro-Supercapacitors.

Science.gov (United States)

Hao, Chunxue; Wang, Lidan; Wen, Fusheng; Xiang, Jianyong; Li, Lei; Hu, Wentao; Liu, Zhongyuan

2017-12-20

Bismuth selenides (Bi2Se3 and Bi3Se4), both of which have the layered rhombohedral crystal structure, and found to be useful as electrode materials for supercapacitor application in this work. Bi2Se3 nanoplates as electrode material exhibit much better performance than that of Bi3Se4 nanoparticles in liquid electrolyte system (6 M KOH), which delivers a higher specific capacitance (272.9 F/g) than that of Bi3Se4 (193.6 F/g) at 5 mV/s. This result would may be attributed to that Bi2Se3 nanoplates possess more active electrochemical surfaces for the reversible surface redox reactions owing to its planar quintuple stacked layers (septuple layers for Bi3Se4). For the demand of electronic skin, we used a novel flexible annular interdigital structure electrode applying for all-solid-state micro-supercapacitors (AMSCs). Bi2Se3 AMSCs device delivers a much more excellent supercapacitor performance, exhibits a large stack capacitance 89.5 F/cm3 (Bi3Se4: 79.1 F/cm3) at 20 mV/s, a high energy density 17.9 mWh/cm3 and high power density 18.9 W/cm3. The bismuth selenides also exhibit good cycle stability, retention 95.5% (90.3%) after 1000 c for Bi2Se3 (Bi3Se4). Obviously, Bi2Se3 nanoplates can be promising electrode materials for flexible annular interdigital all-solid-sate supercapacitor. © 2017 IOP Publishing Ltd.

Estimation of Bi induced changes in the direct E{sub 0} band gap of III–V-Bi alloys and comparison with experimental data

Energy Technology Data Exchange (ETDEWEB)

Samajdar, D.P., E-mail: dipprakash010@gmail.com; Dhar, S.

2016-03-01

Quantum dielectric Theory (QDT) is used to explain the band gap bowing effect observed in III–V-Bismides such as InSb{sub 1−x}Bi{sub x}, InAs{sub 1−x}Bi{sub x}, InP{sub 1−x}Bi{sub x}, GaSb{sub 1−x}Bi{sub x}, GaAs{sub 1−x}Bi{sub x} and GaP{sub 1−x}Bi{sub x.} The dependence of the direct E{sub 0} band gap for these alloys on Bi mole fraction is calculated using QDT which requires the evaluation of the bowing parameter c. The bowing parameter gives the deviation of the direct E{sub 0} band gap from the linear relationship of E{sub 0} with Bi mole fraction. The band gap reduction values obtained using QDT are compared with those calculated using Virtual Crystal approximation (VCA) and Valence Band Anticrossing (VBAC) model as well as with the reported experimental data and the results of the comparison shows excellent agreement.

One-pot solvothermal synthesis of three-dimensional (3D) BiOI/BiOCl composites with enhanced visible-light photocatalytic activities for the degradation of bisphenol-A

International Nuclear Information System (INIS)

Xiao, Xin; Hao, Rong; Liang, Min; Zuo, Xiaoxi; Nan, Junmin; Li, Laisheng; Zhang, Weide

2012-01-01

Highlights: ► Synthesis of 3D BiOI/BiOCl microspheres by a one-pot template-free solvothermal method. ► Photocatalyst is BiOI/BiOCl composites. ► BiOI/BiOCl composites have enhanced visible-light photocatalytic ability to bisphenol-A. ► A simple and direct photodegradation pathway of bisphenol-A is proposed. - Abstract: Three-dimensional (3D) BiOI/BiOCl composite microspheres with enhanced visible-light photodegradation activity of bisphenol-A (BPA) are synthesized by a simple, one-pot, template-free, solvothermal method using BiI 3 and BiCl 3 as precursors. These 3D hierarchical microspheres with heterojunction structures are composed of 2D nanosheets and have composition-dependent absorption properties in the ultraviolet and visible light regions. The photocatalytic oxidation of BPA over BiOI/BiOCl composites followed pseudo first-order kinetics according to the Langmuir–Hinshelwood model. The highest photodegradation efficiency of BPA, i.e., nearly 100%, was observed with the BiOI/BiOCl composite (containing 90% BiOI) using a catalyst dosage of 1 g L −1 in the BPA solution (C 0 = 20 mg L −1 , pH = 7.0) under visible light irradiation for 60 min. Under these conditions, the reaction rate constant was more than 4 and 20 times greater than that of pure BiOI and the commercially available Degussa P25, respectively. The superior photocatalytic activity of this composite catalyst is attributed to the suitable band gap energies and the low recombination rate of the photogenerated electron–hole pairs due to the presence of BiOI/BiOCl heterostructures. Only one intermediate at m/z 151 was observed in the photodegradation process of BPA by liquid chromatography combined with mass spectrometry (LC–MS) analysis, and a simple and hole-predominated photodegradation pathway of BPA was subsequently proposed. Furthermore, this photocatalyst exhibited a high mineralization ratio, high stability and easy separation for recycling use, suggesting that it is a

Synthesis and luminescence enhancement of CaTiO{sub 3}:Bi{sup 3+} yellow phosphor by codoping Al{sup 3+}/B{sup 3+} ions

Energy Technology Data Exchange (ETDEWEB)

Cao, Renping, E-mail: jxcrp@163.com; Fu, Ting; Xu, Haidong; Luo, Wenjie; Peng, Dedong; Chen, Zhiquan; Fu, Jingwei

2016-07-25

CaTiO{sub 3}:Bi{sup 3+} and CaTiO{sub 3}:Bi{sup 3+}, Al{sup 3+}/B{sup 3+} phosphors are synthesized by solid-state reaction method in air. With excitation 272 and 320 nm, broad PL band peaking at 555 nm with full width at half maximum ∼200 nm is observed in the range of 400–800 nm due to the {sup 3}P{sub 1,0} → {sup 1}S{sub 0} transitions of Bi{sup 3+} ion. PLE spectrum monitored at 555 nm contains two PLE band peaking at ∼272 and 320 nm within the range 230–420 nm owing to metal-to-metal charge-transfer and {sup 1}S{sub 0} → {sup 3}P{sub 1} transition of Bi{sup 3+} ion, respectively. The optimal Bi{sup 3+} doping concentration in CaTiO{sub 3}:Bi{sup 3+} phosphor is about 0.5 mol%. Luminescence properties of CaTiO{sub 3}:Bi{sup 3+} phosphor may be improved obviously by co-doping Al{sup 3+}/B{sup 3+} ions, and its emission intensity can be enhanced 13–15 times after Al{sup 3+} ion is co-doped. Luminous mechanism of CaTiO{sub 3}:Bi{sup 3+} phosphor is analyzed by energy level diagram of Bi{sup 3+} ion. Decay curve and time-resolved spectra confirm that only a single type of Bi{sup 3+} luminescence center exists in CaTiO{sub 3}:Bi{sup 3+} phosphor. - Graphical abstract: PL spectra of CaTiO{sub 3}:Bi{sup 3+} and CaTiO{sub 3}:Bi{sup 3+}, Al{sup 3+}/B{sup 3+} phosphors and the corresponding pictures under 365 nm UV lamp. - Highlights: • CaTiO{sub 3}:Bi{sup 3+} and CaTiO{sub 3}:Bi{sup 3+}, Al{sup 3+}/B{sup 3+} phosphors are synthesized by solid-state reaction in air. • Broadband emission with FWHM ∼200 nm is observed within the range 400–800 nm. • Luminescence properties of CaTiO{sub 3}:Bi{sup 3+} phosphor can be improved by codoping Al{sup 3+}/B{sup 3+} ions. • PL intensity of CaTiO{sub 3}:Bi{sup 3+} phosphor can be enhanced 13–15 times after Al{sup 3+} ion is codoped.

In vitro studies of immunoglobulin heavy-chain binding protein (BiP, GRP78). Interactions of BiP with newly synthesized proteins and adenine nucleotides

International Nuclear Information System (INIS)

Kassenbrock, C.K.

1988-01-01

Here we examine the interaction of BiP with newly synthesized polypeptides in an in vitro protein translations-translocation system. We find that BiP forms tight complexes with nonglycosylated yeast invertase and incorrectly disulfide-bonded prolactin but not with glycosylated invertase or correctly disulfide-bonded prolactin. Moreover, BiP associates detectably only with completed chains of prolactin, not with chains undergoing synthesis. We conclude that BiP recognizes and binds with high affinity to aberrantly folded or aberrantly glycosylated polypeptides in vitro, but not to all nascent chains as they are folding. BiP also binds APT and can be purified by APT affinity chromatography. We show that submicromolar levels of ATP or ADP decrease the rate of absorption of 125 I-BiP to nitrocellulose filters coated with protein or nonionic detergents. ATP and ADP also protect portions of BiP from proteolytic degradation. In contrast, micromolar levels of AMP increase the rate of adsorption and the rate of proteolytic degradation of BiP. We also show that an ATPase activity co-purifies with BiP, but its slow turnover number suggests a regulatory, rather than a functional role. The BiP-associated ATPase shares several properties with the related cytoplasmic protein, HSC70/clathrin uncoating ATPase

Coverage Metrics for Model Checking

Science.gov (United States)

Penix, John; Visser, Willem; Norvig, Peter (Technical Monitor)

2001-01-01

When using model checking to verify programs in practice, it is not usually possible to achieve complete coverage of the system. In this position paper we describe ongoing research within the Automated Software Engineering group at NASA Ames on the use of test coverage metrics to measure partial coverage and provide heuristic guidance for program model checking. We are specifically interested in applying and developing coverage metrics for concurrent programs that might be used to support certification of next generation avionics software.

Dielectric and piezoelectric properties of BiFeO3 modified Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 lead-free piezoelectric ceramics

International Nuclear Information System (INIS)

Zhou Changrong; Liu Xinyu; Li Weizhou

2008-01-01

The (0.82 - x)Bi 0.5 Na 0.5 TiO 3 -0.18Bi 0.5 K 0.5 TiO 3 -xBiFeO 3 (x = 0-0.07) lead-free piezoelectric ceramics were fabricated by a conventional solid-state reaction method and the effect of BiFeO 3 addition on microstructure and electrical properties of the ceramics was investigated. The specimens with x ≤ 0.05 maintained a rhombohedral-tetragonal phase coexistence and changed into a rhombohedral phase when x > 0.05 in crystal structure. The addition of BiFeO 3 caused a promoted grain growth. All the specimens reveal a low-frequency dielectric dispersion in the frequency range of 40-1 MHz. The piezoelectric constant d 33 and the electromechanical coupling factor k p show an obvious improvement by the addition of small amount of BiFeO 3 , which shows optimum values of d 33 = 170 pC/N and k p = 0.366 at x = 0.03. Contrary to the enhancement of piezoelectric properties, Q m decreases with increasing BiFeO 3 content. The mechanisms of intrinsic and extrinsic contributions to the dielectric and piezoelectric responses have been proposed. Intrinsic contributions are from the relative ion/cation shift that preserves the ferroelectric crystal structure. The remaining extrinsic contributions are from the domain-wall motion and point defects

Dry etching of ferroelectric Bi4-xEuxTi3O12 (BET) thin films

International Nuclear Information System (INIS)

Lim, Kyu-Tae; Kim, Kyoung-Tae; Kim, Dong-Pyo; Kim, Chang-Il

2004-01-01

Bi 4-x Eu x Ti 3 O 12 (BET) thin films were etched by using a inductively coupled Cl 2 /Ar plasma. We obtained a maximum etch rate of 69 nm/min at a gas mixing ratio of Cl 2 (20 %)/Ar (80 %). This result suggests that an effective method for BET etching is chemically assisted physical etching. With increasing coil RF power, the plasma density increases so that the increased reactive free radicals and ions enhance the etch rates of BET, Pt, and SiO 2 . As the dc-bias voltage is increased, the increased ion energy leads to an increased etch rate of BET films. From X-ray photoelectron spectroscopy, the intensities of the Bi-O, the Eu-O, and the Ti-O peaks change with increasing Cl 2 concentration. For a pure Ar plasma, the peak associated with the oxygen-metal (O-M: TiO 2 , Bi 2 O 3 , Eu 2 O 3 ) bond seems to disappear while the pure oxygen peak does not appear. After the BET thin films is etched by using a Cl 2 /Ar plasma, the peak associated with the O-M bond increases slowly, but more quickly than the peak associated with pure oxygen atoms, due to a decrease in the Ar-ion bombardment. These results seem to indicate that Bi and Eu react little with Cl atoms and are removed predominantly by argon-ion bombardment. Also, Ti reacts little with Cl radicals and is mainly removed by chemically assisted physical etching.

Crystal Structure of AgBi2I7 Thin Films.

Science.gov (United States)

Xiao, Zewen; Meng, Weiwei; Mitzi, David B; Yan, Yanfa

2016-10-06

Synthesis of cubic-phase AgBi 2 I 7 iodobismuthate thin films and fabrication of air-stable Pb-free solar cells using the AgBi 2 I 7 absorber have recently been reported. On the basis of X-ray diffraction (XRD) analysis and nominal composition, it was suggested that the synthesized films have a cubic ThZr 2 H 7 crystal structure with AgBi 2 I 7 stoichiometry. Through careful examination of the proposed structure and computational evaluation of the phase stability and bandgap, we find that the reported "AgBi 2 I 7 " films cannot be forming with the ThZr 2 H 7 -type structure, but rather more likely adopt an Ag-deficient AgBiI 4 type. Both the experimental X-ray diffraction pattern and bandgap can be better explained by the AgBiI 4 structure. Additionally, the proposed AgBiI 4 structure, with octahedral bismuth coordination, removes unphysically short Bi-I bonding within the [BiI 8 ] hexahedra of the ThZr 2 I 7 model. Our results provide critical insights for assessing the photovoltaic properties of AgBi 2 I 7 iodobismuthate materials.

Electronic structure of the BiSI cluster

Energy Technology Data Exchange (ETDEWEB)

Audzijonis, A. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania); Gaigalas, G. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania); Institute of Theoretical Physics and Astronomy, Vilnius University, A. Gostauto 12, LT-01108 Vilnius (Lithuania); Zigas, L. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania)]. E-mail: kkol@vpu.lt; Pauliukas, A. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania); Zaltauskas, R. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania); Cerskus, A. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania); Narusis, J. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania); Institute of Theoretical Physics and Astronomy, Vilnius University, A. Gostauto 12, LT-01108 Vilnius (Lithuania); Kvedaravicius, A. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania)

2007-03-15

The energy levels of valence bands (VB) and core levels (CL) of the BiSI crystals have been investigated theoretically. The molecular model of this crystal was used for calculation of VB and CL by the unrestricted Hartree-Fock method using GAMESS program, with Hw and MINI basis set. The molecular cluster consisting of 20 molecules of BiSI was used for calculations of averaged total density of states including atom vibrations. The spectra of averaged total density of states from VB of BiSI cluster has been compared with experimental X-ray photoelectron spectra (XPS) of VB of SbSI crystal. The results clarify that the atomic vibrations is one of possible reasons for the smoother appearance of the experimental XPS. The investigation of vibrational spectrum reveals new experimental information about the reflection spectrum of BiSI crystals. The cluster model calculations have shown that the splitting of the CL in the BiSI may be caused by the photoelectron emission from the atoms at the surface that is in different valence states. The cluster model calculation showed that splitting energy of CL depends on difference of ionic charges of the same atoms at the edges of BiSI cluster.

Electronic structure of the BiSI cluster

International Nuclear Information System (INIS)

Audzijonis, A.; Gaigalas, G.; Zigas, L.; Pauliukas, A.; Zaltauskas, R.; Cerskus, A.; Narusis, J.; Kvedaravicius, A.

2007-01-01

The energy levels of valence bands (VB) and core levels (CL) of the BiSI crystals have been investigated theoretically. The molecular model of this crystal was used for calculation of VB and CL by the unrestricted Hartree-Fock method using GAMESS program, with Hw and MINI basis set. The molecular cluster consisting of 20 molecules of BiSI was used for calculations of averaged total density of states including atom vibrations. The spectra of averaged total density of states from VB of BiSI cluster has been compared with experimental X-ray photoelectron spectra (XPS) of VB of SbSI crystal. The results clarify that the atomic vibrations is one of possible reasons for the smoother appearance of the experimental XPS. The investigation of vibrational spectrum reveals new experimental information about the reflection spectrum of BiSI crystals. The cluster model calculations have shown that the splitting of the CL in the BiSI may be caused by the photoelectron emission from the atoms at the surface that is in different valence states. The cluster model calculation showed that splitting energy of CL depends on difference of ionic charges of the same atoms at the edges of BiSI cluster

Modification of photosensing property of CdS–Bi{sub 2}S{sub 3} bi-layer by thermal annealing and swift heavy ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Shaikh, Shaheed U.; Siddiqui, Farha Y. [Thin Film and Nanotechnology Laboratory, Department of Physics (India); Department of Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004 (India); Singh, Fouran; Kulriya, Pawan K. [Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Phase, D.M. [UGC DAE Consortium for Scientific Research, Khandwa Road, Indore 452017 (India); Sharma, Ramphal, E-mail: ramphalsharma@yahoo.com [Thin Film and Nanotechnology Laboratory, Department of Physics (India); Department of Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004 (India)

2016-02-01

The CdS–Bi{sub 2}S{sub 3} bi-layer thin films have been deposited on Indium Tin Oxide (ITO) glass substrates at room temperature by Chemical Bath Deposition Technique (CBD) and bi-layer thin films were annealed in air atmosphere for 1 h at 250 {sup °}C. The air annealed sample was irradiated using Au{sup 9+} ions at the fluence 5 × 10{sup 11} ion/cm{sup 2} with 120 MeV energy. Effects of Swift Heavy Ion (SHI) irradiation on CdS–Bi{sub 2}S{sub 3} bi-layer thin films were studied. The results are explained on the basis annealing and high electronic excitation, using X-ray diffraction (XRD), Selective Electron Area Diffraction (SEAD), Atomic Force Microscopy (AFM), Raman Spectroscopy, UV spectroscopy and I–V characteristics. The photosensing property after illumination of visible light over the samples is studied. These as-deposited, annealed and irradiated bi-layer thin films are used to sense visible light at room temperature. - Graphical abstract: Schematic illustration of CdS–Bi{sub 2}S{sub 3} bi-layer thin film (a) As-deposited (b) Annealed (c) irradiated sample respectively (d) Model of bi-layer photosensor device (e) Graph of illumination intensity verses photosensitivity. - Highlights: • CdS–Bi{sub 2}S{sub 3} bi-layer thin film prepared at room temperature. • Irradiated using Au{sup 9+} ions at the fluence of 5 × 10{sup 11} ion/cm{sup 2} with 120 MeV energy. • Study of modification induced by irradiations. • Study of Photosensitivity after annealing and irradiation.

Thermoelectric properties of p-type (Bi{sub 1{minus}x}Sb{sub x}){sub 2}Te{sub 3} fabricated by mechanical alloying process

Energy Technology Data Exchange (ETDEWEB)

Jung, B Y; Choi, J S; Oh, T S; Hyun, D B

1997-07-01

Thermoelectric properties of polycrystalline (Bi{sub 1{minus}x}Sb{sub x}){sub 2}Te{sub 3} (0.75 {le} x {le} 0.85), fabricated by mechanical alloying and hot pressing methods, have been investigated. Formation of (Bi{sub 0.25}Sb{sub 0.75}){sub 2}Te{sub 3} alloy powder was completed by mechanical alloying for 5 hours at ball-to-material ratio of 5:1, and processing time for (Bi{sub 1{minus}sub x}Sb{sub x}){sub 2}Te{sub 3} formation increased with Sb{sub 2}Te{sub 3} content x. When (Bi{sub 0.25}Sb{sub 0.75}){sub 2}Te{sub 3} was hot pressed at temperatures ranging from 300 C to 550 C for 30 minutes, figure-of-merit increased with hot pressing temperature and maximum value of 2.8 x 10{sup {minus}3}/K could be obtained by hot pressing at 550 C. When hot pressed at 550 C, (Bi{sub 0.2}Sb{sub 0.8}){sub 2}Te{sub 3} exhibited figure-of-merit of 2.92 x 10{sup {minus}3}/K, which could be improved to 2.97 x 10{sup {minus}3}/K with addition of 1 wt% Sb as acceptor dopant.

Spatio-temporal observations of the tertiary ozone maximum

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V. F. Sofieva

2009-07-01

Full Text Available We present spatio-temporal distributions of the tertiary ozone maximum (TOM, based on GOMOS (Global Ozone Monitoring by Occultation of Stars ozone measurements in 2002–2006. The tertiary ozone maximum is typically observed in the high-latitude winter mesosphere at an altitude of ~72 km. Although the explanation for this phenomenon has been found recently – low concentrations of odd-hydrogen cause the subsequent decrease in odd-oxygen losses – models have had significant deviations from existing observations until recently. Good coverage of polar night regions by GOMOS data has allowed for the first time to obtain spatial and temporal observational distributions of night-time ozone mixing ratio in the mesosphere.

The distributions obtained from GOMOS data have specific features, which are variable from year to year. In particular, due to a long lifetime of ozone in polar night conditions, the downward transport of polar air by the meridional circulation is clearly observed in the tertiary ozone maximum time series. Although the maximum tertiary ozone mixing ratio is achieved close to the polar night terminator (as predicted by the theory, TOM can be observed also at very high latitudes, not only in the beginning and at the end, but also in the middle of winter. We have compared the observational spatio-temporal distributions of the tertiary ozone maximum with that obtained using WACCM (Whole Atmosphere Community Climate Model and found that the specific features are reproduced satisfactorily by the model.

Since ozone in the mesosphere is very sensitive to HO_x concentrations, energetic particle precipitation can significantly modify the shape of the ozone profiles. In particular, GOMOS observations have shown that the tertiary ozone maximum was temporarily destroyed during the January 2005 and December 2006 solar proton events as a result of the HO_x enhancement from the increased ionization.

BiDil: from another vantage point.

Science.gov (United States)

Puckrein, Gary

2006-01-01

In a recent Health Affairs Web Exclusive, Pamela Sankar and Jonathan Kahn argue against the Food and Drug Administration's approval of BiDil as a new drug for the treatment of heart failure in African Americans. Their paper questions the existence of disparities between African American and other heart-failure patients and the motivations of BiDil's developers and manufacturer. The disparities are confirmed and persistent, however, and BiDil's effectiveness is proven. If the authors' logic were to prevail, patients would be denied life-saving therapy. Continued investigation will likely narrow identification of patients who will benefit.

Effect of Bi on the corrosion resistance of zirconium alloys

International Nuclear Information System (INIS)

Yao Meiyi; Zhou Bangxin; Li Qiang; Zhang Weipeng; Zhu Li; Zou Linghong; Zhang Jinlong; Peng Jianchao

2014-01-01

In order to investigate systematically the effect of Bi addition on the corrosion resistance of zirconium alloys, different zirconium-based alloys, including Zr-4 (Zr-l.5Sn-0.2Fe-0.1Cr), S5 (Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr), T5 (Zr-0.7Sn-l.0Nb-0.3Fe-0.1Cr) and Zr-1Nb, were adopted to prepare the zirconium alloys containing Bi of 0∼0.5% in mass fraction. These alloys were denoted as Zr-4 + xBi, S5 + xBi, T5 + xBi and Zr-1Nb + xBi, respectively. The corrosion behavior of these specimens was investigated by autoclave testing in lithiated water with 0.01 M LiOH or deionized water at 360 ℃/18.6 MPa and in superheated steam at 400 ℃/10.3 MPa. The microstructure of the alloys was examined by TEM and the second phase particles (SPPs) were analyzed by EDS. Microstructure observation shows that the addition of Bi promotes the precipitation of Sn as second phase particles (SPPs) because Sn is in solid solution in α-Zr matrix in Zr-4, S5 and T5 alloys. The concentration of Bi dissolved in α-Zr matrix increase with the increase of Nb in the alloys, and the excess Bi precipitates as Bi-containing SPPs. The corrosion results show that the effect of Bi addition on the corrosion behavior of different zirconium-based alloys is very complicated, depending on their compositions and corrosion conditions. In the case of higher Bi concentration in α-Zr, the zirconium alloys exhibit better corrosion resistance. However, in the case of precipitation of Bi-containing SPPs, the corrosion resistance gets worse. This indicates that the solid solution of Bi in α-Zr matrix can improve the corrosion resistance, while the precipitation of the Bi-containing SPPs is harmful to the corrosion resistance. (authors)

Preparation of 2D square-like Bi2S3-BiOCl heterostructures with enhanced visible light-driven photocatalytic performance for dye pollutant degradation

Directory of Open Access Journals (Sweden)

Jing-jing Xu

2017-10-01

Full Text Available A series of Bi2S3-BiOCl composites with two-dimensional (2D square-like structures were prepared via a two-step anion exchange route. X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and diffuse reflectance spectra (DRS were used to investigate the properties of the as-prepared Bi2S3-BiOCl heterostructures. The coupling of BiOCl and Bi2S3 induced enhanced photoabsorption efficiency and bandgap narrowing. A reactive brilliant red X-3B dye was used as a contaminant to test the photocatalytic activity of the obtained Bi2S3-BiOCl samples under visible light irradiation. The sample Bi2S3-BiOCl with a mass ratio of 8:4 exhibited the highest photodegradation efficiency, which was six times higher than that of pure BiOCl. In addition, a mechanism for the enhancement of photocatalytic activity is proposed.

Synthesis and melting behaviour of Bi, Sn and Sn–Bi nanostructured alloy

Energy Technology Data Exchange (ETDEWEB)

Frongia, F.; Pilloni, M.; Scano, A.; Ardu, A.; Cannas, C.; Musinu, A. [Università di Cagliari, Dipartimento di Scienze Chimiche e Geologiche and Cagliari Research Unit of the National Consortium of Materials Science and Technology (INSTM), Cittadella Universitaria di Monserrato, 09042 Monserrato, CA (Italy); Borzone, G.; Delsante, S. [Department of Chemistry and Industrial Chemistry, Genoa University and Genoa Research Unit of the National Consortium of Materials Science and Technology (INSTM), Via Dodecaneso 31, I-16146 Genoa (Italy); Novakovic, R. [National Research Council (CNR), Institute for Energetics and Interphases (IENI), Via De Marini 6, 16149 Genoa (Italy); Ennas, G., E-mail: ennas@unica.it [Università di Cagliari, Dipartimento di Scienze Chimiche e Geologiche and Cagliari Research Unit of the National Consortium of Materials Science and Technology (INSTM), Cittadella Universitaria di Monserrato, 09042 Monserrato, CA (Italy)

2015-02-25

Highlights: • Aqueous solution route is used to produce Bi, Sn and Bi–Sn nanoparticles. • HRTEM revealed core–shell and Janus type structures of Bi–Sn nanoparticles. • Melting temperature depression of Bi and Bi–Sn nanoparticles were measured by DSC. • DSC data on Bi melting temperature depression agrees with theoretical values. - Abstract: Lead-free solders based on Bi–Sn bimetallic nanoclusters with eutectic composition (Bi{sub 43}Sn{sub 57}) were synthesized at low temperature by simultaneous reduction reaction from aqueous solution containing bismuth and tin chlorides, using potassium borohydride as a reducing agent. By the same processing route, pure bismuth and tin nanoparticles have also been prepared. Microstructure, morphology and composition of the samples were characterized by X-ray powder diffraction (XRD), transmission (TEM) and scanning electron microscopy (SEM). TEM images of Bi–Sn nanoparticles show average size ranging from 30 to 100 nm. Thermal behaviour of Bi–Sn nanopowders was studied by DSC (differential scanning calorimetry) and a melting temperature (135 °C) lower than that of the corresponding microcrystalline sample (139 °C) was observed. SEM micrographs of the thermally treated sample up to 400 °C show fine spherical grains in the micrometer range with finer powder particles on the surface. XRD powder diffraction analysis indicates the formation of bismuth and tin nanophases with an average particle size of 85 and 126 nm, respectively. The oxidation behaviour of the samples was also investigated. The results obtained have been analyzed in view of theoretical models describing the melting temperature depression of nanoparticles.

Effects of rye grass coverage on soil loss from loess slopes

Directory of Open Access Journals (Sweden)

Yuequn Dong

2015-09-01

Full Text Available Vegetative coverage is commonly used to reduce urban slope soil erosion. Laboratory experimental study on soil erosion under grass covered slopes is conventionally time and space consuming. In this study, a new method is suggested to study the influences of vegetation coverage on soil erosion from a sloped loess surface under three slope gradients of 5°, 15°, and 25°; four rye grass coverages of 0%, 25%, 50%, and 75%; and three rainfall intensities of 60, 90, and 120 mm/h with a silt-loamy loess soil. Rye grasses were planted in the field with the studied soil before being transplanted into a laboratory flume. Grass was allowed to resume growth for a period before the rain simulation experiment. Results showed that the grass cover reduced soil erosion by 63.90% to 92.75% and sediment transport rate by 80.59% to 96.17% under different slope gradients and rainfall intensities. The sediment concentration/sediment transport rate from bare slope was significantly higher than from a grass-covered slope. The sediment concentration/transport rate from grass-covered slopes decreased linearly with grass coverage and increased with rainfall intensity. The sediment concentration/transport rate from the bare slope increased as a power function of slope and reached the maximum value at the gradient of about 25°, whereas that from grass-covered slope increased linearly and at much lower levels. The results of this study can be used to estimate the effect of vegetation on soil erosion from loess slopes.

Structural properties of superconducting Bi-2223/Ag tapes

Energy Technology Data Exchange (ETDEWEB)

Gottschalck Andersen, L.

2001-05-01

The structural properties of silver clad high-T{sub c} superconducting ceramic tapes of (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) have been investigated by means of synchrotron X-ray diffraction (including the 3DXRD microscope setup), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS). By synchrotron X-ray diffraction in situ studies of the phase development during the transformation of (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub x} (Bi-2212) into Bi-2223, the stoichiometry changes and the texture have been performed during annealing in 8% O{sub 2} and in air. Furthermore, an annealing with two high temperature cycles has been performed to study the equilibrium phenomena. During heating (Ca,Sr){sub 2}PbO{sub 4} decomposes at temperatures between 700 deg. C and 840 deg.C. Simultaneously, the Bi-2212 lattice contracts, indicating an incorporation of Pb. Moreover, the grain mis-alignment decreases significantly. In air we have observed that Bi-2212 partly dissociates into (Ca,Sr){sub 2}CuO{sub 3} and a liquid at temperatures above 812 deg. C. At the annealing temperature Bi-2212 and (Ca,Sr){sub 2}CuO{sub 3} react with the liquid to form Bi-2223. The transformation mechanism is discussed. During cooling below {approx}750 deg.C (Ca,Sr){sub 2}CuO{sub 3} and the liquid mainly transform into Bi-2201. Below {approx}780 deg. C Bi-2223 decomposes to 3221. In addition, a two-step cooling experiment and a decomposition study have been performed in 8% O{sub 2}. By TEM the grain and colony size in the c-axis direction, the angles of c-axis tilt grain boundaries and the intergrowth content are investigated. A fully processed tape has on average 50% thicker grains than a tape after the 1st annealing. The angles of c-axis tilt grain boundaries are on average 14 deg. and 26 deg. for the fully processed tape and the tape after the 1st annealing, respectively. The intergrowth content (15%) and

Contact interaction of the Bi12GeO20, Bi12SiO20, and Bi4Ge3O12 melts with noble metals

Science.gov (United States)

Denisov, V. M.; Podkopaev, O. I.; Denisova, L. T.; Kuchumova, O. V.; Istomin, S. A.; Pastukhov, E. A.

2014-02-01

The sessile drop method is used to study the contact interaction of Ag, Au, Pd, Pt, and Ir with the Bi2O3-GeO2 and Bi2O3-SiO2 melts. These melts spread over Ag and Pd and, in some cases, over Au and Pt at a rather high speed and form equilibrium contact angles on Ir.

Determination of the impact of Bi content on the valence band energy of GaAsBi using x-ray photoelectron spectroscopy

Directory of Open Access Journals (Sweden)

K. Collar

2017-07-01

Full Text Available We investigate the change of the valence band energy of GaAs1-xBix (0Bi concentration, x, using x-ray photoelectron spectroscopy (XPS. The change in the valence band energy per addition of 1 % Bi is determined for strained and unstrained thin films using a linear approximation applicable to the dilute regime. Spectroscopic ellipsometry (SE was used as a complementary technique to determine the change in GaAsBi bandgap resulting from Bi addition. Analysis of SE and XPS data together supports the conclusion that ∼75% of the reduction in the bandgap is in the valence band for a compressively strained, dilute GaAsBi thin film at room temperature.

On atomic mechanisms governing the oxidation of Bi2Te3

Science.gov (United States)

Music, Denis; Chang, Keke; Schmidt, Paul; Braun, Felix N.; Heller, Martin; Hermsen, Steffen; Pöllmann, Peter J.; Schulzendorff, Till; Wagner, Cedric

2017-12-01

Oxidation of Bi2Te3 (space group R \\overline{3} m) has been investigated using experimental and theoretical means. Based on calorimetry, x-ray photoelectron spectroscopy and thermodynamic modelling, Bi2Te3 is at equilibrium with Bi2O3 and TeO2, whereby the most stable compound is Bi2Te3, followed by Bi2O3. The reactivity of Bi towards oxygen is expected to be higher than that of Te. This notion is supported by density functional theory. The strongest bond is formed between Bi and Te, followed by Bi-O. This gives rise to unanticipated atomic processes. Dissociatively adsorbed oxygen diffuses through Bi and Te basal planes of Bi2Te3(0 0 0 1) and preferably interacts with Bi. The Te termination considerably retards this process. These findings may clarify conflicting literature data. Any basal plane off-cut or Bi terminations trigger oxidation, but a perfect basal cleavage, where only Te terminations are exposed to air, may be stable for a longer period of time. These results are of relevance for applications in which surfaces are of key importance, such as nanostructured Bi2Te3 thermoelectric devices.

Design and fabrication of a 30 T superconducting solenoid using overpressure processed Bi2212 round wire

Energy Technology Data Exchange (ETDEWEB)

Flanagan, Gene [Muons, Inc., Batavia, IL (United States); Johnson, Rolland [Muons, Inc., Batavia, IL (United States)

2016-02-18

High field superconducting magnets are used in particle colliders, fusion energy devices, and spectrometers for medical imaging and advanced materials research. Magnets capable of generating fields of 20-30 T are needed by future accelerator facilities. A 20-30 T magnet will require the use of high-temperature superconductors (HTS) and therefore the challenges of high field HTS magnet development need to be addressed. Superconducting Bi₂Sr₂CaCu₂O_x (Bi2212) conductors fabricated by the oxide-powder-in-tube (OPIT) technique have demonstrated the capability to carry large critical current density of 10⁵ A/cm² at 4.2 K and in magnetic fields up to 45 T. Available in round wire multi-filamentary form, Bi2212 may allow fabrication of 20-50 T superconducting magnets. Until recently the performance of Bi2212 has been limited by challenges in realizing high current densities (J_c ) in long lengths. This problem now is solved by the National High Magnetic Field Lab using an overpressure (OP) processing technique, which uses external pressure to process the conductor. OP processing also helps remove the ceramic leakage that results when Bi-2212 liquid leaks out from the sheath material and reacts with insulation, coil forms, and flanges. Significant advances have also been achieved in developing novel insulation materials (TiO₂ coating) and Ag-Al sheath materials that have higher mechanical strengths than Ag-0.2wt.% Mg, developing heat treatment approaches to broadening the maximum process temperature window, and developing high-strength, mechanical reinforced Bi-2212 cables. In the Phase I work, we leveraged these new opportunities to prototype overpressure processed solenoids and test them in background fields of up to 14 T. Additionally a design of a fully superconducting 30 T solenoid was produced. This work in conjunction with the future path outlined in the Phase II proposal would

Fabricaion of improved novel p–n junction BiOI/Bi{sub 2}Sn{sub 2}O{sub 7} nanocomposite for visible light driven photocatalysis

Energy Technology Data Exchange (ETDEWEB)

Xu, Weicheng [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Jianzhang, E-mail: fangjzh@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China); Zhu, Ximiao [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Zhanqiang [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China); Cen, Chaoping [The Key Laboratory of Water and Air Pollution Control of Guangdong Province, South China Institute of Environmental Sciences, Guangzhou 510655 (China)

2015-12-15

Graphical abstract: - Highlights: • A p–n heterojunction photocatalyst BiOI/Bi{sub 2}Sn{sub 2}O{sub 7} was prepared by hydrothermal method. • 4% BiOI/Bi{sub 2}Sn{sub 2}O{sub 7} with maximal photocatalytic degradation efficiency (RhB) of 99.9%. • A specific degradation routes of RhB was illustrated. • The photocatalytic mechanism is discussed according to p–n junction principles. • • O{sub 2}{sup −} and h+ are the main reactive species for the degradation of RhB. - Abstract: A series of novel p−n junction photocatalysts BiOI/Bi{sub 2}Sn{sub 2}O{sub 7} (BiOI/BSO) were successfully fabricated via a facile hydrothermal method. The phase structures, morphologies and optical properties of the as-prepared samples were studied by XRD, TEM, HRTEM, BET, XPS, UV–vis DRS and photoluminescence (PL) spectroscopy. The results showed that BiOI/BSO heteronanostructures displayed much higher photocatalytic activity than pure BSO and BiOI for the degradation of rhodamine B (RhB). The best photocatalytic activity of BiOI/BSO with almost 99.9% RhB degradation situated at molar percentage ratio of 4% after 6 h irradiation. The enhanced photocatalytic performance of BiOI/BSO could be mainly attributed to the formation of the heterojunction between p-BiOI and n-BSO, which effectively restrains the recombination of photoinduced electron–hole pairs. Moreover, the study of radical scavengers affirmed that h{sup +} and • O{sub 2}{sup −} were the primary reactive species for the degradation of RhB.

Chemical casting of high-Tc superconducting BiSCCO

International Nuclear Information System (INIS)

Toth, L.E.; Das, B.N.; Rayne, R.J.; Bender, B.A.; Lechter, W.L.; Hoff, H.A.; Osofsky, M.S.; Soulen, R.J. Jr.

1989-01-01

BiSCCO has been successfully cast into a number of useful shapes. This casting process differs significantly from traditional casting in that the process includes a change in the oxygen content of the melt. A heat treatment is required to restore the original chemistry, properly form the BiSCCO crystal structure and develop the superconducting properties. This paper emphasizes the microstructures of as-cast and heat treated BiSCCO. Casting causes considerable grain alignment of the BiSCCO platelets. The platelets align preferentially along the thermal gradients which exist during the solidification process

Synthesis, crystal structure, and physical properties of the Gd{sub 3}BiO{sub 3} and Gd{sub 8}Bi{sub 3}O{sub 8} phases

Energy Technology Data Exchange (ETDEWEB)

Forbes, Scott; Yuan, Fang [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Kosuda, Kosuke; Kolodiazhnyi, Taras [Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Mozharivskyj, Yurij, E-mail: mozhar@mcmaster.ca [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada)

2016-01-15

The second and third known rare-earth bismuthide oxides, Gd{sub 3}BiO{sub 3} and Gd{sub 8}Bi{sub 3}O{sub 8}, have been discovered via high temperature reactions at 1300 °C. Like its Gd–Sb–O counterparts, the Gd{sub 3}BiO{sub 3} and Gd{sub 8}Bi{sub 3}O{sub 8} phases crystallize in the monoclinic C2/m space group, with the latter containing disordered Bi atoms along the b direction of the unit cell. Unlike the RE{sub 8}Sb{sub 3}O{sub 8} series, the formation of the Gd{sub 3}BiO{sub 3} phase does not necessarily precede the formation of Gd{sub 8}Bi{sub 3}O{sub 8}, which is likely due to the difficulty of accommodating bismuth in the RE–O framework due to its larger size. Physical property measurements performed on a pure Gd{sub 8}Bi{sub 3}O{sub 8} sample reveal semiconducting behavior. Although electronic structure calculations predict metallic behavior due to an unbalanced electron count, the semiconducting behavior originates from the Anderson localization of the Bi p states near the Fermi level as a result of atomic disorder. - Graphical abstract: Reaction of GdBi and Gd{sub 2}O{sub 3} at high temperatures yields Gd–Bi–O phases. - Highlights: • Gd{sub 3}BiO{sub 3} and Gd{sub 8}Bi{sub 3}O{sub 8}, the second and third rare-earth bismuthide oxides, have been discovered. • Gd{sub 3}BiO{sub 3} and Gd{sub 8}Bi{sub 3}O{sub 8} are isostructural with RE{sub 3}SbO{sub 3} and RE{sub 8}Sb{sub 3}O{sub 8}. • Gd{sub 8}Bi{sub 3}O{sub 8} displays semiconducting behavior despite an unbalanced electron count. • Anderson localization of Bi p states results in semiconducting behavior in Gd{sub 8}Bi{sub 3}O{sub 8}.

High-pressure studies of superconductivity in BiO0. 75F0. 25BiS2

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 40; Issue 6. High-pressure studies of superconductivity in BiO 0.75 F 0.25 BiS 2. ZEBA HAQUE GOHIL S THAKUR GANESAN KALAI SELVAN SONACHALAM ARUMUGAM L C GUPTA A K GANGULI. Volume 40 Issue 6 October 2017 pp 1121-1125 ...

Spectroscopy of 214Bi and systematics of 210,212,214Pb(0+) long->β-210,212,214Bi(0-)

International Nuclear Information System (INIS)

Berant, Z.; Schuhmann, R.B.; Alburger, D.E.; Chou, W.T.; Gill, R.L.; Warburton, E.K.; Wesselborg, C.

1991-01-01

Experiments designed to provide more information on the spectroscopy of 214 Bi, and on 214 Pb(β - ) 214 Bi in particular, were undertaken because of interest in first-forbidden β decay in the lead region. The experiments consisted of γ-γ coincidences and angular correlations, conversion electron measurements, level lifetime determinations, and precision γ-ray energy measurements. The 352-keV level of 214 Bi was found to be a strong candidate (and the only candidate) for the 0 1 - state. Recent additions to the 214 Pb decay scheme are confirmed by γ-γ coincidence measurements. A careful evaluation of the 214 Bi level scheme is made with emphasis on separating experimentally based conclusions from speculations based on systematics and other ''weak'' arguments. Shell-model calculations of the spectroscopy of 210,212 Bi and 210,212 Pb(β - ) 210,212 Bi were performed using a modification of the Kuo-Herling realistic interaction. These calculations and a generalized seniority model provide a basis for an examination of the systematics of the A=210, 212, 214 spectroscopy and β decay. The generalized seniority model is found to be a quite good approximation which provides a quantitative understanding of the 214 Pb decay rates

Photocatalytic removal of tetrabromobisphenol A by magnetically separable flower-like BiOBr/BiOI/Fe{sub 3}O{sub 4} hybrid nanocomposites under visible-light irradiation

Energy Technology Data Exchange (ETDEWEB)

Gao, Shengwang [Department of Chemistry, College of Science, North University of China, Taiyuan 030051 (China); State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Guo, Changsheng; Hou, Song; Wan, Li [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Wang, Qiang [Heilongjiang Research Academy of Environmental Sciences, Harbin 150056 (China); Lv, Jiapei; Zhang, Yuan [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Gao, Jianfeng [Department of Chemistry, College of Science, North University of China, Taiyuan 030051 (China); Meng, Wei [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Xu, Jian, E-mail: xujian@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)

2017-06-05

Highlights: • A novel BiOBr/BiOI/Fe{sub 3}O{sub 4} hybrid nanocomposites was prepared for the first time. • BiOBr-BiOI-Fe{sub 3}O{sub 4} (2:2:0.5) displays superior photocatalytic activity for TBBPA. • Good magnetic property makes it easy for the material’s recovery from solution. • The photocatalytic reaction mechanism of BiOBr/BiOI/Fe{sub 3}O{sub 4} was proposed. • Superoxide radical is the dominant ROS in TBBPA degradation. - Abstract: A novel flower-like three-dimensional BiOBr/BiOI/Fe{sub 3}O{sub 4} heterojunction photocatalyst was synthesized using a simple in situ co-precipitation method at room temperature. The hybrid composites were characterized by a couple of techniques including X-ray powder diffraction, scanning electron microscope, transmission electron microscopy, ultraviolet-visible diffuse reflection spectroscopy, Brunauer-Emmett-Teller, X-ray photo-electron spectroscopy, photoluminescence technique, and vibrating sample magnetometer. Fe{sub 3}O{sub 4} nanoparticles were perfectly loaded on the surface of BiOBr/BiOI microspheres. The recyclable magnetic BiOBr/BiOI/Fe{sub 3}O{sub 4} was employed to degrade TBBPA under visible light irradiation. The optimal removal efficiency of the ternary BiOBr/BiOI/Fe{sub 3}O{sub 4} (2:2:0.5) nanocomposite reached up to 98.5% for TBBPA in aqueous solution. The superior photocatalytic activity of BiOBr/BiOI/Fe{sub 3}O{sub 4} was mainly ascribed to large surface area and appropriate energy gaps, resulting in the effective adsorption and separation of electrons-hole pairs. The photogenerated reactive species determined by free radicals trapping experiments revealed that the excellent catalytic activity was primarily driven by ·O{sub 2}{sup −} radical. The photocatalytic degradation kinetics and a detailed mechanism were also proposed. Result demonstrated that the BiOBr/BiOI/Fe{sub 3}O{sub 4} can be magnetically recycled, and maintain high photocatalytic activity after reuse over five cycles. It

One-pot solvothermal synthesis of three-dimensional (3D) BiOI/BiOCl composites with enhanced visible-light photocatalytic activities for the degradation of bisphenol-A

Energy Technology Data Exchange (ETDEWEB)

Xiao, Xin [School of Chemistry and Environment, South China Normal University, Key Lab of Theoretical Chemistry of Environment, Guangzhou 510006 (China); Nano Science Research Center, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Hao, Rong; Liang, Min; Zuo, Xiaoxi [School of Chemistry and Environment, South China Normal University, Key Lab of Theoretical Chemistry of Environment, Guangzhou 510006 (China); Nan, Junmin, E-mail: jmnan@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Key Lab of Theoretical Chemistry of Environment, Guangzhou 510006 (China); Li, Laisheng [School of Chemistry and Environment, South China Normal University, Key Lab of Theoretical Chemistry of Environment, Guangzhou 510006 (China); Zhang, Weide [Nano Science Research Center, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China)

2012-09-30

Highlights: Black-Right-Pointing-Pointer Synthesis of 3D BiOI/BiOCl microspheres by a one-pot template-free solvothermal method. Black-Right-Pointing-Pointer Photocatalyst is BiOI/BiOCl composites. Black-Right-Pointing-Pointer BiOI/BiOCl composites have enhanced visible-light photocatalytic ability to bisphenol-A. Black-Right-Pointing-Pointer A simple and direct photodegradation pathway of bisphenol-A is proposed. - Abstract: Three-dimensional (3D) BiOI/BiOCl composite microspheres with enhanced visible-light photodegradation activity of bisphenol-A (BPA) are synthesized by a simple, one-pot, template-free, solvothermal method using BiI{sub 3} and BiCl{sub 3} as precursors. These 3D hierarchical microspheres with heterojunction structures are composed of 2D nanosheets and have composition-dependent absorption properties in the ultraviolet and visible light regions. The photocatalytic oxidation of BPA over BiOI/BiOCl composites followed pseudo first-order kinetics according to the Langmuir-Hinshelwood model. The highest photodegradation efficiency of BPA, i.e., nearly 100%, was observed with the BiOI/BiOCl composite (containing 90% BiOI) using a catalyst dosage of 1 g L{sup -1} in the BPA solution (C{sub 0} = 20 mg L{sup -1}, pH = 7.0) under visible light irradiation for 60 min. Under these conditions, the reaction rate constant was more than 4 and 20 times greater than that of pure BiOI and the commercially available Degussa P25, respectively. The superior photocatalytic activity of this composite catalyst is attributed to the suitable band gap energies and the low recombination rate of the photogenerated electron-hole pairs due to the presence of BiOI/BiOCl heterostructures. Only one intermediate at m/z 151 was observed in the photodegradation process of BPA by liquid chromatography combined with mass spectrometry (LC-MS) analysis, and a simple and hole-predominated photodegradation pathway of BPA was subsequently proposed. Furthermore, this photocatalyst

Improved photoelectrochemical performance of Z-scheme g-C{sub 3}N{sub 4}/Bi{sub 2}O{sub 3}/BiPO{sub 4} heterostructure and degradation property

Energy Technology Data Exchange (ETDEWEB)

Li, Junqi, E-mail: sfmlab@163.com; Yuan, Huan; Zhu, Zhenfeng

2016-11-01

Highlights: • A novel Z-scheme g-C{sub 3}N{sub 4}/Bi{sub 2}O{sub 3}/BiPO{sub 4} composite was synthesized. • The Z-scheme system we made can remain the strong reducibility and oxidizability of the photocatalysts. • The solar light was made the utmost use both the ultraviolet and visible region light through the g-C{sub 3}N{sub 4}/Bi{sub 2}O{sub 3}/BiPO{sub 4} composite. - Abstract: In g-C{sub 3}N{sub 4}/Bi{sub 2}O{sub 3}/BiPO{sub 4}, the p–n junction between p-type Bi{sub 2}O{sub 3} and n-type BiPO{sub 4} was encapsulated by g-C{sub 3}N{sub 4} and a direct Z-scheme was built between g-C{sub 3}N{sub 4} and Bi{sub 2}O{sub 3}. The optical, morphological and photoelectrochemical (PEC) properties of BiPO{sub 4}, g-C{sub 3}N{sub 4}/BiPO{sub 4}, Bi{sub 2}O{sub 3}/BiPO{sub 4} and g-C{sub 3}N{sub 4}/Bi{sub 2}O{sub 3}/BiPO{sub 4} hierarchical Z-scheme system were studied. More than 90% photodegradation of methyl orange (MO) with the exposure of simulated solar light was achieved within 160 min with the g-C{sub 3}N{sub 4}/Bi{sub 2}O{sub 3}/BiPO{sub 4}, which displayed remarkably promoted photocatalytic activities than other samples. The electrochemical impedance spectra and photocurrent results also proved that efficient charge separation and better electron transport properties were achieved by g-C{sub 3}N{sub 4}/Bi{sub 2}O{sub 3}/BiPO{sub 4}. In general, the addition of g-C{sub 3}N{sub 4} can guide the residual electrons on p-type Bi{sub 2}O{sub 3} to recombine with photoholes of g-C{sub 3}N{sub 4} and make sure the left carries exhibit stronger oxidation and reduction ability to boost the production of active groups.

5 CFR 890.1106 - Coverage.

Science.gov (United States)

2010-01-01

... family member is an individual whose relationship to the enrollee meets the requirements of 5 U.S.C. 8901... EMPLOYEES HEALTH BENEFITS PROGRAM Temporary Continuation of Coverage § 890.1106 Coverage. (a) Type of enrollment. An individual who enrolls under this subpart may elect coverage for self alone or self and family...

BiCluE - Exact and heuristic algorithms for weighted bi-cluster editing of biomedical data

DEFF Research Database (Denmark)

Sun, Peng; Guo, Jiong; Baumbach, Jan

2013-01-01

to solve the weighted bi-cluster editing problem. It implements (1) an exact algorithm based on fixed-parameter tractability and (2) a polynomial-time greedy heuristics based on solving the hardest part, edge deletions, first. We evaluated its performance on artificial graphs. Afterwards we exemplarily...... problem. BiCluE as well as the supplementary results are available online at http://biclue.mpi-inf.mpg.de webcite....

Effect of cold working on the corrosion resistance of JPCA stainless steel in flowing Pb–Bi at 450 °C

International Nuclear Information System (INIS)

Rivai, Abu Khalid; Saito, Shigeru; Tezuka, Masao; Kato, Chiaki; Kikuchi, Kenji

2012-01-01

Development of a high performance proton beam window material is one of the critical issues for the deployment of the accelerator-driven transmutation system (ADS) with liquid Pb–Bi eutectic as a spallation target and coolant. In the present study, we applied 20% cold work treatment to JPCA austenitic stainless steel and investigated it from the corrosion behavior viewpoint. The corrosion test of 20% cold-worked JPCA SS has been carried in the JLBL-1 (JAEA Lead–Bismuth Loop-1) apparatus. The maximum temperature, the temperature difference, the flow velocity and the exposure time of the liquid Pb–Bi were 450 °C, 100 °C, 1 m/s, and 1000 h, respectively. For comparison analysis, JPCA SS without cold working was also tested in the same time and conditions with the 20% cold-worked JPCA SS. The results showed a different corrosion behavior between the JPCA SS without and with cold working. As for the JPCA SS without cold working, Pb–Bi penetrated into the matrix through a ferrite layer which was formed because of constituent metals dissolution from the matrix into Pb–Bi. As for the 20% cold-worked JPCA SS, dissolution attack occurred only partially and formed localized superficial pitting corrosion. It was found that the different corrosion behavior occurred because the cold working induced a structure transformation from γ-austenite to α′-martensite and affected the corrosion resistance of the JPCA SS in flowing Pb–Bi at 450 °C.

29 CFR 801.3 - Coverage.

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Coverage. 801.3 Section 801.3 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR OTHER LAWS APPLICATION OF THE EMPLOYEE POLYGRAPH PROTECTION ACT OF 1988 General § 801.3 Coverage. (a) The coverage of the Act extends to “any...

Thermoelectric Properties of Cu-Doped n-Type Bi2Te2.85Se0.15 Prepared by Liquid Phase Growth Using a Sliding Boat

Science.gov (United States)

Kitagawa, Hiroyuki; Matsuura, Tsukasa; Kato, Toshihito; Kamata, Kin-ya

2015-06-01

N-type Bi2Te2.85Se0.15 thermoelectric materials were prepared by liquid phase growth (LPG) using a sliding boat, a simple and short fabrication process for Bi2Te3-related materials. Cu was selected as a donor dopant, and its effect on thermoelectric properties was investigated. Thick sheets and bars of Cu x Bi2 Te2.85Se0.15 ( x=0-0.25) of 1-2mm in thickness were obtained using the process. X-ray diffraction patterns and scanning electron micrographs showed that the in-plane direction tended to correspond to the hexagonal c-plane, which is the preferred direction for thermoelectric conversion. Cu-doping was effective in controlling conduction type and carrier (electron) concentration. The conduction type was p-type for undoped Bi2Te2.85Se0.15 and became n-type after Cu-doping. The Hall carrier concentration was increased by Cu-doping. Small resistivity was achieved in Cu0.02Bi2Te2.85Se0.15 owing to an optimized amount of Cu-doping and high crystal orientation. As a result, the maximum power factor near 310K for Cu0.02Bi2Te2.85Se0.15 was approximately 4×10-3W/K2m and had good reproducibility. Furthermore, the thermal stability of Cu0.02Bi2Te2.85Se0.15 was also confirmed by thermal cycling measurements of electrical resistivity. Thus, n-type Bi2Te2.85Se0.15 with a large power factor was prepared using the present LPG process.

BI-AMALGAMATION OF SMALL WEAK GLOBAL DIMENSION

OpenAIRE

Tamekkante, Mohammed; Bouba, El Mehdi

2017-01-01

In this paper, we characterize the bi-Amalgamations of small weakglobal dimension. The new results compare to previous works carried on varioussettings of duplications and amalgamations, and capitalize on recent resultson bi-amalgamations

TOOL ASSEMBLY WITH BI-DIRECTIONAL BEARING

Science.gov (United States)

Longhurst, G.E.

1961-07-11

A two-direction motion bearing which is incorporated in a refueling nuclear fuel element trsnsfer tool assembly is described. A plurality of bi- directional bearing assembliesare fixed equi-distantly about the circumference of the transfer tool assembly to provide the tool assembly with a bearing surface- for both axial and rotational motion. Each bi-directional bearing assembly contains a plurality of circumferentially bulged rollers mounted in a unique arrangement which will provide a bearing surface for rotational movement of the tool assembly within a bore. The bi-direc tional bearing assembly itself is capable of rational motion and thus provides for longitudinal movement of the tool assembly.

Synthesis of C@Bi{sub 2}MoO{sub 6} nanocomposites with enhanced visible light photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Sun, Yuying; Wu, Juan; Ma, Tianjin; Wang, Pengchao; Cui, Chunyue; Ma, Dong, E-mail: madong8088@126.com

2017-05-01

Highlights: • C@BM composites were obtained by two–step hydrothermal method. • The properties of Bi{sub 2}MoO{sub 6} were deeply influenced by carbon layer. • Carbon could reduce recombination of electrons and holes in C@BM composites. • The holes and ·O{sub 2}{sup −} are the two main reactive species for Rh B degradation. - Abstract: Carbon–coated Bi{sub 2}MoO{sub 6} (C@BM) composites have been successfully synthesized via two–step hydrothermal method. The morphology, structure and photocatalytic performance of the composites in the degradation of Rhodamine B (Rh B) are characterized. The results show that the C@BM composites exhibit enhanced photocatalytic performance in the degradation of Rh B with maximum degradation rates of 90% (210 min) under visible light irradiation. 1.0%C@BM sample shows the highest photocatalytic activity, and the improved photocatalytic performance is mainly ascribed to the formation of Mo−O−C and Bi−O−C bonds. The bonds could promote electron transfer from Bi{sub 2}MoO{sub 6} to carbon layer and inhibit the recombination of electron–hole pairs with the presence of carbon layer in the composites. Moreover, the carbon layer on Bi{sub 2}MoO{sub 6} could enhance the absorption in the visible light region. In the photocatalytic degradation process, ·O{sub 2}{sup −}and holes are the predominant active species for the decomposition of Rh B.

BiVO4 nanoparticles: Preparation, characterization and photocatalytic activity

Directory of Open Access Journals (Sweden)

Venkataraman Sivakumar

2015-12-01

Full Text Available Bismuth vanadate (BiVO4 nanoparticles were synthesized by a simple thermal decomposition method. The synthesized bismuth vanadate nanoparticles were characterized by X-ray diffraction analysis, it is found that the synthesized sample belongs to monoclinic BiVO4. Fourier transform infrared spectroscopy confirms the formation of Bi-O bond in the sample. Ultraviolet–Visible (DRS-UV–Visible spectroscopy and photoluminescence spectroscopy reveal the optical property of the BiVO4 nanoparticles. The morphology was identified by both scanning electron microscopy and high-resolution transmission electron microscopy. Further, the photocatalytic activity of BiVO4 nanoparticles was investigated by photodegradation of methylene blue as a model organic pollutant.

Coverage-based constraints for IMRT optimization

Science.gov (United States)

Mescher, H.; Ulrich, S.; Bangert, M.

2017-09-01

Radiation therapy treatment planning requires an incorporation of uncertainties in order to guarantee an adequate irradiation of the tumor volumes. In current clinical practice, uncertainties are accounted for implicitly with an expansion of the target volume according to generic margin recipes. Alternatively, it is possible to account for uncertainties by explicit minimization of objectives that describe worst-case treatment scenarios, the expectation value of the treatment or the coverage probability of the target volumes during treatment planning. In this note we show that approaches relying on objectives to induce a specific coverage of the clinical target volumes are inevitably sensitive to variation of the relative weighting of the objectives. To address this issue, we introduce coverage-based constraints for intensity-modulated radiation therapy (IMRT) treatment planning. Our implementation follows the concept of coverage-optimized planning that considers explicit error scenarios to calculate and optimize patient-specific probabilities q(\\hat{d}, \\hat{v}) of covering a specific target volume fraction \\hat{v} with a certain dose \\hat{d} . Using a constraint-based reformulation of coverage-based objectives we eliminate the trade-off between coverage and competing objectives during treatment planning. In-depth convergence tests including 324 treatment plan optimizations demonstrate the reliability of coverage-based constraints for varying levels of probability, dose and volume. General clinical applicability of coverage-based constraints is demonstrated for two cases. A sensitivity analysis regarding penalty variations within this planing study based on IMRT treatment planning using (1) coverage-based constraints, (2) coverage-based objectives, (3) probabilistic optimization, (4) robust optimization and (5) conventional margins illustrates the potential benefit of coverage-based constraints that do not require tedious adjustment of target volume objectives.

Monitoring intervention coverage in the context of universal health coverage.

Directory of Open Access Journals (Sweden)

Ties Boerma

2014-09-01

Full Text Available Monitoring universal health coverage (UHC focuses on information on health intervention coverage and financial protection. This paper addresses monitoring intervention coverage, related to the full spectrum of UHC, including health promotion and disease prevention, treatment, rehabilitation, and palliation. A comprehensive core set of indicators most relevant to the country situation should be monitored on a regular basis as part of health progress and systems performance assessment for all countries. UHC monitoring should be embedded in a broad results framework for the country health system, but focus on indicators related to the coverage of interventions that most directly reflect the results of UHC investments and strategies in each country. A set of tracer coverage indicators can be selected, divided into two groups-promotion/prevention, and treatment/care-as illustrated in this paper. Disaggregation of the indicators by the main equity stratifiers is critical to monitor progress in all population groups. Targets need to be set in accordance with baselines, historical rate of progress, and measurement considerations. Critical measurement gaps also exist, especially for treatment indicators, covering issues such as mental health, injuries, chronic conditions, surgical interventions, rehabilitation, and palliation. Consequently, further research and proxy indicators need to be used in the interim. Ideally, indicators should include a quality of intervention dimension. For some interventions, use of a single indicator is feasible, such as management of hypertension; but in many areas additional indicators are needed to capture quality of service provision. The monitoring of UHC has significant implications for health information systems. Major data gaps will need to be filled. At a minimum, countries will need to administer regular household health surveys with biological and clinical data collection. Countries will also need to improve the

Adjacent level effects of bi level disc replacement, bi level fusion and disc replacement plus fusion in cervical spine--a finite element based study.

Science.gov (United States)

Faizan, Ahmad; Goel, Vijay K; Biyani, Ashok; Garfin, Steven R; Bono, Christopher M

2012-03-01

Studies delineating the adjacent level effect of single level disc replacement systems have been reported in literature. The aim of this study was to compare the adjacent level biomechanics of bi-level disc replacement, bi-level fusion and a construct having adjoining level disc replacement and fusion system. In total, biomechanics of four models- intact, bi level disc replacement, bi level fusion and fusion plus disc replacement at adjoining levels- was studied to gain insight into the effects of various instrumentation systems on cranial and caudal adjacent levels using finite element analysis (73.6N+varying moment). The bi-level fusion models are more than twice as stiff as compared to the intact model during flexion-extension, lateral bending and axial rotation. Bi-level disc replacement model required moments lower than intact model (1.5Nm). Fusion plus disc replacement model required moment 10-25% more than intact model, except in extension. Adjacent level motions, facet loads and endplate stresses increased substantially in the bi-level fusion model. On the other hand, adjacent level motions, facet loads and endplate stresses were similar to intact for the bi-level disc replacement model. For the fusion plus disc replacement model, adjacent level motions, facet loads and endplate stresses were closer to intact model rather than the bi-level fusion model, except in extension. Based on our finite element analysis, fusion plus disc replacement procedure has less severe biomechanical effects on adjacent levels when compared to bi-level fusion procedure. Bi-level disc replacement procedure did not have any adverse mechanical effects on adjacent levels. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

Synthesis of Bi2Sr2CaCu2O8+δ whiskers and cross-whisker intrinsic Josephson junction

International Nuclear Information System (INIS)

Hatano, T.; Takano, Y.; Arisawa, S.; Ishii, A.; Togano, K.; Fukuyo, A.

2001-01-01

A synthesis technique of Bi 2 Sr 2 CaCu 2 O 8+δ single-crystal whiskers was studied. The whiskers were synthesized by heating glassy melt-quenched Bi-Sr-Ca-Cu-O (3:2:2:4 in cationic ratio) plates. The atmospheric condition of the whisker growth, especially oxygen partial pressure and gas flow, was investigated. It was found out that the whisker growth rate shows a maximum at P O2 =2/3 bar. For the crystalline quality of the whiskers, the airtight condition was found to be useful as compared to the conventional oxygen stream condition. The crystalline quality, especially the straightness and morphology of the surface, could be improved by keeping the growing whiskers under the equilibrium P Bi condition. Over 20-mm-long whisker crystals have been successfully synthesized by choosing optimum oxygen partial pressure around the P O2 =2/3 bar in the airtight condition. The growth condition and mechanism of the Bi 2 Sr 2 CaCu 2 O 8+δ whiskers were investigated by an in-situ high-temperature x-ray diffraction analysis and an in-situ high-temperature microscope observation. It was found that the whiskers grow in a partially melted state at a temperature of 10-40 degrees below the melting point. The result obtained demonstrates that Bi 2 Sr 2 CaCu 2 O 8+δ whiskers grow at their bottom by the conventional liquid-phase growth mechanism, as was proposed by Matsubara et al. (author)

Fuzzy Bi-cooperative games in multilinear extension form

Czech Academy of Sciences Publication Activity Database

Borkotokey, S.; Hazarika, P.; Mesiar, Radko

2015-01-01

Roč. 259, č. 1 (2015), s. 44-55 ISSN 0165-0114 R&D Projects: GA ČR GAP402/11/0378 Institutional support: RVO:67985556 Keywords : Fuzzy Bi-cooperative games * Bi-cooperative game * Bi-coalition * LG value Subject RIV: BA - General Mathematics Impact factor: 2.098, year: 2015 http://library.utia.cas.cz/separaty/2015/E/mesiar-0442007.pdf

Increasing the coverage area through relay node deployment in long term evolution advanced cellular networks

Science.gov (United States)

Aldhaibani, Jaafar A.; Ahmad, R. B.; Yahya, A.; Azeez, Suzan A.

2015-05-01

Wireless multi-hop relay networks have become very important technologies in mobile communications. These networks ensure high throughput and coverage extension with a low cost. The poor capacity at cell edges is not enough to meet with growing demand of high capacity and throughput irrespective of user's placement in the cellular network. In this paper we propose optimal placement of relay node that provides maximum achievable rate at users and enhances the throughput and coverage at cell edge region. The proposed scheme is based on the outage probability at users and taken on account the interference between nodes. Numerical analyses along with simulation results indicated there are an improvement in capacity for users at the cell edge is 40% increment from all cell capacity.

Photocatalytic Degradation of Methyl Orange on Bi2O3 and Ag2O-Bi2O3 Nano Photocatalysts

Directory of Open Access Journals (Sweden)

Seyed Ali Hosseini

2017-04-01

Full Text Available The photocatalytic activity of Bi2O3 and Ag2O-Bi2O3 was evaluated by degradation of aqueous methyl orange as a model dye effluent. Bi2O3 was synthesized using chemical precipitation method. Structural analysis revealed that Bi2O3 contain a unique well-crystallized phase and the average crystallite size of 22.4 nm. The SEM analysis showed that the size of Bi2O3 particles was mainly in the range of 16-22 nm. The most important variables affecting the photocatalytic degradation of dyes, namely reaction time, initial pH and catalyst dosage were studied, and their optimal amounts were found at 60 min, 5.58 and 0.025 g, respectively. A good correlation was found between experimental and predicted responses, confirming the reliability of the model. Incorporation of Ag2O in the structure of composite caused decreasing band gap and its response to visible light. Because a high percentage of sunlight is visible light, hence Ag2O-Bi2O3 nano-composite could be used as an efficient visible light driven photocatalyst for degradation of dye effluents by sunlight. Copyright © 2017 BCREC GROUP. All rights reserved Received: 15th August 2016; Revised: 20th December 2016; Accepted: 21st December 2016 How to Cite: Hosseini, S.A., Saeedi, R. (2017. Photocatalytic Degradation of Methyl Orange on Bi2O3 and Ag2O-Bi2O3 Nano Photocatalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1: 96-105 (doi:10.9767/bcrec.12.1.623.96-105 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.623.96-105

Generalized bi-quasi-variational inequalities for quasi-semi-monotone and bi-quasi-semi-monotone operators with applications in non-compact settings and minimization problems

Directory of Open Access Journals (Sweden)

Chowdhury Molhammad SR

2000-01-01

Full Text Available Results are obtained on existence theorems of generalized bi-quasi-variational inequalities for quasi-semi-monotone and bi-quasi-semi-monotone operators in both compact and non-compact settings. We shall use the concept of escaping sequences introduced by Border (Fixed Point Theorem with Applications to Economics and Game Theory, Cambridge University Press, Cambridge, 1985 to obtain results in non-compact settings. Existence theorems on non-compact generalized bi-complementarity problems for quasi-semi-monotone and bi-quasi-semi-monotone operators are also obtained. Moreover, as applications of some results of this paper on generalized bi-quasi-variational inequalities, we shall obtain existence of solutions for some kind of minimization problems with quasi- semi-monotone and bi-quasi-semi-monotone operators.

Metaheuristics for bi-level optimization

CERN Document Server

2013-01-01

This book provides a complete background on metaheuristics to solve complex bi-level optimization problems (continuous/discrete, mono-objective/multi-objective) in a diverse range of application domains. Readers learn to solve large scale bi-level optimization problems by efficiently combining metaheuristics with complementary metaheuristics and mathematical programming approaches. Numerous real-world examples of problems demonstrate how metaheuristics are applied in such fields as networks, logistics and transportation, engineering design, finance and security.

Cooperative Cloud Service Aware Mobile Internet Coverage Connectivity Guarantee Protocol Based on Sensor Opportunistic Coverage Mechanism

Directory of Open Access Journals (Sweden)

Qin Qin

2015-01-01

Full Text Available In order to improve the Internet coverage ratio and provide connectivity guarantee, based on sensor opportunistic coverage mechanism and cooperative cloud service, we proposed the coverage connectivity guarantee protocol for mobile Internet. In this scheme, based on the opportunistic covering rules, the network coverage algorithm of high reliability and real-time security was achieved by using the opportunity of sensor nodes and the Internet mobile node. Then, the cloud service business support platform is created based on the Internet application service management capabilities and wireless sensor network communication service capabilities, which is the architecture of the cloud support layer. The cooperative cloud service aware model was proposed. Finally, we proposed the mobile Internet coverage connectivity guarantee protocol. The results of experiments demonstrate that the proposed algorithm has excellent performance, in terms of the security of the Internet and the stability, as well as coverage connectivity ability.

Heat treatment control of Bi-2212 coils: I. Unravelling the complex dependence of the critical current density of Bi-2212 wires on heat treatment

Science.gov (United States)

Shen, Tengming; Li, Pei; Ye, Liyang

2018-01-01

A robust and reliable heat treatment is crucial for developing superconducting magnets from several superconductors especially Bi-2212. An improper heat treatment may significantly reduce the critical current density Jc of a Bi-2212 superconducting coil, even to zero, since the Jc of Bi-2212 wires is sensitive to parameters of its heat treatment (partial melt processing). To provide an essential database for heat treating Bi-2212 coils, the dependence of Jc on heat treatment is studied systematically in 11 industrial Bi-2212 wires, revealing several common traits shared between these wires and outlier behaviors. The dependence of the Jc of Bi-2212 on heat treatment is rather complex, with many processing parameters affecting Jc, including the peak processing temperature Tp, the time at the peak temperature tp, the time in the melt tmelt, the rate at which Bi-2212 melt is initially cooled CR1, the rate at which the solidification of Bi-2212 melt occurs CR2, and the temperature Tq at which the cooling rate switches from CR1 to CR2. The role of these parameters is analyzed and clarified, in the perspective of heat treating a coil. Practical advices on heat treatment design are given. The ability of a Bi-2212 coil to follow the prescribed recipe decreases with increasing coil sizes. The size of a coil that can be properly heat treated is determined.

How choices in exchange design for states could affect insurance premiums and levels of coverage.

Science.gov (United States)

Blavin, Fredric; Blumberg, Linda J; Buettgens, Matthew; Holahan, John; McMorrow, Stacey

2012-02-01

The Affordable Care Act gives states the option to create health insurance exchanges from which individuals and small employers can purchase health insurance. States have considerable flexibility in how they design and implement these exchanges. We analyze several key design options being considered, using the Urban Institute's Health Insurance Policy Simulation Model: creating separate versus merged small-group and nongroup markets, eliminating age rating in these markets, removing the small-employer credit, and setting the maximum number of employees for firms in the small-group market at 50 versus 100 workers. Among our findings are that merging the small-group and nongroup markets would result in 1.7 million more people nationwide participating in the exchanges and, because of greater affordability of nongroup coverage, approximately 1.0 million more people being insured than if the risk pools were not merged. The various options generate relatively small differences in overall coverage and cost, although some, such as reducing age rating bands, would result in higher costs for some people while lowering costs for others. These cost effects would be most apparent among people who purchase coverage without federal subsidies. On the whole, we conclude that states can make these design choices based on local support and preferences without dramatic repercussions for overall coverage and cost outcomes.

Structural determination of Bi-doped magnetite multifunctional nanoparticles for contrast imaging.

Science.gov (United States)

Laguna-Marco, M A; Piquer, C; Roca, A G; Boada, R; Andrés-Vergés, M; Veintemillas-Verdaguer, S; Serna, C J; Iadecola, A; Chaboy, J

2014-09-14

To determine with precision how Bi atoms are distributed in Bi-doped iron oxide nanoparticles their structural characterization has been carried out by X-ray absorption spectroscopy (XAS) recorded at the K edge of Fe and at the L3 edge of Bi. The inorganic nanoparticles are nominally hybrid structures integrating an iron oxide core and a bismuth oxide shell. Fe K-edge XAS indicates the formation of a structurally ordered, non-stoichiometric magnetite (Fe3-δO4) phase for all the nanoparticles. The XAS spectra show that, in the samples synthesized by precipitation in aqueous media and laser pyrolysis, the Bi atoms neither enter into the iron oxide spinel lattice nor form any other mixed Bi-Fe oxides. No modification of the local structure around the Fe atoms induced by the Bi atoms is observed at the Fe K edge. In addition, contrary to expectations, our results indicate that the Bi atoms do not form a well-defined Bi oxide structure. The XAS study at the Bi L3 edge indicates that the environment around Bi atoms is highly disordered and only a first oxygen coordination shell is observed. Indefinite [BiO6-x(OH)x] units (isolated or aggregated forming tiny amorphous clusters) bonded through hydroxyl bridges to the nanoparticle, rather than a well defined Bi2O3 shell, surround the nanoparticle. On the other hand, the XAS study indicates that, in the samples synthesized by thermal decomposition, the Bi atoms are embedded in a longer range ordered structure showing the first and second neighbors.

Processing Y- and Bi-based superconductors

International Nuclear Information System (INIS)

Balachandran, U.; Dos Santos, D.I.; von Stumberg, A.W.; Graham, S.W.; Singh, J.P.; Youngdahl, C.A.; Goretta, K.C.; Shi, D.; Poeppel, R.B.

1989-01-01

This paper reports on bulk specimens of YBa 2 Cu 3 O x and Bi 2 Sr 2 CaCu 2 O y formed and then processed by sintering in the solid state, in the presence of a liquid phase, or by sinter forging. Both Y- and Bi-based superconductors are difficult to densify by solid-state sintering but easy to densify in the presence of a liquid phase. Effects of sintering conditions on superconducting properties are, however, different between the two materials. These differences will be discussed. Attempts to texture microstructures and increase J c by sinter-forging techniques have been successful for Y-based superconductors, but unsuccessful for Bi-based superconductors

Low cycle fatigue lifetime of HIP bonded Bi-metallic first wall structures of fusion reactors

Energy Technology Data Exchange (ETDEWEB)

Hatano, Toshihisa; Sato, Satoshi; Furuya, Kazuyuki; Kuroda, Toshimasa; Enoeda, Mikio; Takatsu, Hideyuki [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Hashimoto, Toshiyuki; Kitamura, Kazunori

1998-10-01

A HIP bonded bi-metallic panel composed of a dispersion strengthened copper (DSCu) layer and type 316L stainless steel (SS316L) cooling pipes is the reference design of the ITER first wall. To examine the fatigue lifetime of the first wall panel under cyclic mechanical loads, low cycle fatigue tests of HIP bonded bi-metallic specimens made of SS316L and DSCu were conducted with the stress ratio of -1.0 and five nominal strain range conditions ranging from 0.2 to 1.0%. Elasto-plastic analysis has also been conducted to evaluate local strain ranges under the nominal strains applied. Initial cracks were observed at the inner surface of the SS316L cooling pipes for all of the specimens tested, which was confirmed by the elasto-plastic analysis that the maximum strains of the test specimens were developed at the same locations. It was found that the HIP bonded bi-metallic test specimens had a fatigue lifetime longer than that of the SS316L raw material obtained by round bar specimens. Similarly, the fatigue lifetime of the DSCu/SS316L HIP interface was also longer than the round bar test results for the HIP joints. From these results, it has been confirmed that the bi-metallic first wall panel with built-in cooling pipes made by HIP bonding has a sufficient fatigue lifetime in comparison with the raw fatigue data of the materials, which also suggests that the fatigue lifetime evaluation has an adequate margin against fracture if it follows the design fatigue curve based on the material fatigue data. (author)

The localized effect of the Bi level on the valence band in the dilute bismuth GaBixAs1-x alloy

Science.gov (United States)

Zhao, Chuan-Zhen; Zhu, Min-Min; Wang, Jun; Wang, Sha-Sha; Lu, Ke-Qing

2018-05-01

The research on the temperature dependence of the band gap energy of the dilute bismuth GaBixAs1-x alloy has been done. It is found that its temperature insensitiveness is due to the enhanced localized character of the valence band state and the small decrease of the temperature coefficient for the conduction band minimum (CBM). The enhanced localized character of the valence band state is the main factor. In order to describe the localized effect of the Bi levels on the valence band, the localized energy is introduced into the Varshni's equation. It is found that the effect of the localized Bi level on the valence band becomes strong with increasing Bi content. In addition, it is found that the pressure dependence of the band gap energy of GaBixAs1-x does not seem to be influenced by the localized Bi levels. It is due to two factors. One is that the pressure dependence of the band gap energy is mainly determined by the D CBM of GaBixAs1-x. The D CBM of GaBixAs1-x is not influenced by the localized Bi levels. The other is that the small variation of the pressure coefficient for the D valence band maximum (VBM) state of GaBixAs1-x can be cancelled by the variation of the pressure coefficient for the D CBM state of GaBixAs1-x.

Crossed BiOI flake array solar cells

Energy Technology Data Exchange (ETDEWEB)

Wang, Kewei; Jia, Falong; Zhang, Lizhi [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan (China); Zheng, Zhi [Institute of Surface Micro and Nano Materials, Xuchang University (China)

2010-12-15

We report a new kind of solar cell based on crossed flake-like BiOI arrays for the first time. The BiOI flake arrays were fabricated on an FTO glass with a TiO{sub 2} block layer at room temperature by successive ionic layer adsorption and reaction (SILAR) method. The resulting BiOI flake array solar cell exhibited enhanced photovoltaic performance under solar illumination. This work provides an attractive and new solar cell system and a facile route to fabricate low cost and non-toxic solar cell. (author)

The luminescence of CaWO4: Bi single crystals

International Nuclear Information System (INIS)

Zorenko, Yu.; Pashkovsky, M.; Voloshinovskii, A.; Kuklinski, B.; Grinberg, M.

2006-01-01

Influence of doping with Bi 3+ ions and Bi 3+ -Na + or Bi 3+ -Li + ions pairs on luminescence, emission kinetics and light yield of CaWO 4 crystals has been investigated. It has been shown that under excitation in the A-band at 272 and 287nm, related to the Bi 3+ ions absorption, the luminescence peaked at 468nm decaying with time τ=0.41μs is observed. For bismuth concentration 50-500ppm and the equimolar concentrations of the Bi 3+ ions accompanied by Na + or Li + ions compensators the significant suppression of the phosphorescence peaked at 520nm, related to the defect WO 3 -V O complex, and an improvement of scintillation characteristics of the CaWO 4 are noticed. Energy transfer from the defect WO 3 -V O and regular WO 4 2- oxy-anions to Bi 3+ ions have been observed at room temperatures and discussed

The Quantum Chemistry Calculation and Thermoelectrics of Bi-Sb-Te Series

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

The density function theory and discrete variation method(DFT-DVM) was used to study correlation between composition, structure, chemical bond,and property of thermoelectrics of Bi-Sb-Te series.8 models of Bi20-xSbxTe32(x=0,2,6,8,12,14,18 and 20) were calculated.The results show that there is less difference in the ionic bonds between Te(Ⅰ)-Bi(Sb) and Te(Ⅱ)-Bi(Sb), but the covalent bond of Te(Ⅰ)-Bi(Sb) is stronger than that of Te(Ⅱ)-Bi(Sb).The interaction between Te(Ⅰ) and Te(Ⅰ) in different layers is the weakest and the interaction should be Van Der Waals power.The charge of Sb is lower than that of Bi,and the ionic bond of Te-Sb is weaker than that of Te-Bi.The covalent bond of Te-Sb is also weaker than that of Te-Bi.Therefore,the thermoelectric property may be improved by adjusting the electrical conductivity and thermal conductivity through changing the composition in the compounds of Bi-Sb-Te. The calculated results are consistent with the experiments.

Orbital-dependent Rashba coupling in bulk BiTeCl and BiTeI

KAUST Repository

Zhu, Zhiyong

2013-02-06

By all-electron ab initio calculations, the layered polar semiconductor BiTeCl is shown to host giant bulk Rashba spin splitting, similar to the recently reported compound BiTeI. In both materials, the standard Rashba–Bychkov model is no longer applicable, because of huge band extrema shifts even in the absence of spin–orbit coupling and a strong momentum dependence of the Rashba coupling constant (αR). By assuming αR to be orbital dependent, a phenomenological extension of the Rashba–Bychkov model is proposed which explains the splitting behavior of states with small in-plane momentum.

Orbital-dependent Rashba coupling in bulk BiTeCl and BiTeI

KAUST Repository

Zhu, Zhiyong; Cheng, Yingchun; Schwingenschlö gl, Udo

2013-01-01

By all-electron ab initio calculations, the layered polar semiconductor BiTeCl is shown to host giant bulk Rashba spin splitting, similar to the recently reported compound BiTeI. In both materials, the standard Rashba–Bychkov model is no longer applicable, because of huge band extrema shifts even in the absence of spin–orbit coupling and a strong momentum dependence of the Rashba coupling constant (αR). By assuming αR to be orbital dependent, a phenomenological extension of the Rashba–Bychkov model is proposed which explains the splitting behavior of states with small in-plane momentum.

The influence of Bi content on dielectric properties of Bi4–xTi3O12–1.5x ceramics

Directory of Open Access Journals (Sweden)

Hui Gong

2017-06-01

Full Text Available A kind of lead-free dielectric materials, such as the bismuth layered perovskite-type structure of Bi4–xTi3O12–1.5x (x=0.04,0.02,0,–0.02,–0.04, was prepared by the conventional solid-state method at 800∘C and sintered at 1100∘C. The variation of structure and electrical properties with different Bi concentration was studied. All the Bi4–xTi3O12–1.5x (x=0.04,0.02,0,–0.02,–0.04 samples exhibited a single structured phase. SEM could be a better approach to present the microstructure of Bi4–xTi3O12–1.5x (x=0.04,0.02,0,–0.02,–0.04 ceramics. It could be found that the grain size of Bi4.02Ti3O12.03 sintered at 1100∘C was smaller than that of others among the five samples through grain size mechanics. Through impedance spectra analysis, we knew, when the Bi content was fixed, that the dielectric constant and the loss values increased with the decrease of frequency. The Curie temperature of the five samples was about 670∘C. In particular, while at the frequency of 100kHz, the lowest loss was 0.001 when Bi content was 3.98. The Bi4.02Ti3O12.03 ceramics with the minimum grain size had highest dielectric constant and the relatively low loss. Due to its high Curie temperature, high permittivity and low loss, the Bi4Ti3O12 (BIT ceramics have a broad application prospect in high density memory, generator, sensor, ferroelectric tunnel junctions and so on.

PRECONDITIONED BI-CONJUGATE GRADIENT METHOD FOR RADIATIVE TRANSFER IN SPHERICAL MEDIA

International Nuclear Information System (INIS)

Anusha, L. S.; Nagendra, K. N.; Paletou, F.; Leger, L.

2009-01-01

A robust numerical method called the Preconditioned Bi-Conjugate Gradient (Pre-BiCG) method is proposed for the solution of the radiative transfer equation in spherical geometry. A variant of this method called Stabilized Preconditioned Bi-Conjugate Gradient (Pre-BiCG-STAB) is also presented. These are iterative methods based on the construction of a set of bi-orthogonal vectors. The application of the Pre-BiCG method in some benchmark tests shows that the method is quite versatile, and can handle difficult problems that may arise in astrophysical radiative transfer theory.

Dependence of US hurricane economic loss on maximum wind speed and storm size

International Nuclear Information System (INIS)

Zhai, Alice R; Jiang, Jonathan H

2014-01-01

Many empirical hurricane economic loss models consider only wind speed and neglect storm size. These models may be inadequate in accurately predicting the losses of super-sized storms, such as Hurricane Sandy in 2012. In this study, we examined the dependences of normalized US hurricane loss on both wind speed and storm size for 73 tropical cyclones that made landfall in the US from 1988 through 2012. A multi-variate least squares regression is used to construct a hurricane loss model using both wind speed and size as predictors. Using maximum wind speed and size together captures more variance of losses than using wind speed or size alone. It is found that normalized hurricane loss (L) approximately follows a power law relation with maximum wind speed (V max ) and size (R), L = 10 c V max a R b , with c determining an overall scaling factor and the exponents a and b generally ranging between 4–12 and 2–4 respectively. Both a and b tend to increase with stronger wind speed. Hurricane Sandy’s size was about three times of the average size of all hurricanes analyzed. Based on the bi-variate regression model that explains the most variance for hurricanes, Hurricane Sandy’s loss would be approximately 20 times smaller if its size were of the average size with maximum wind speed unchanged. It is important to revise conventional empirical hurricane loss models that are only dependent on maximum wind speed to include both maximum wind speed and size as predictors. (letters)

Synthesis of Er(III)/Yb(III)-doped BiF3 upconversion nanoparticles for use in optical thermometry.

Science.gov (United States)

Du, Peng; Yu, Jae Su

2018-03-23

The authors describe an ethylene glycol assisted precipitation method for synthesis of Er(III)/Yb(III)-doped BiF 3 nanoparticles (NPs) at room temperature. Under 980-nm light irradiation, the NPs emit upconversion (UC) emission of Er(III) ions as a result of a two-photon absorption process. The temperature-dependent green emissions (peaking at 525 and 545 nm) are used to establish an unambiguous relationship between the ratio of fluorescence intensities and temperature. The NPs have a maximum sensitivity of 6.5 × 10 -3  K -1 at 619 K and can be applied over the 291-691 K temperature range. The results indicate that these NPs are a promising candidate for optical thermometry. Graphical abstract Schematic of the room-temperature preparation of Er(III)/Yb(III)-doped BiF 3 nanoparticles with strongly temperature-dependent upconversion emission.

Bi-orderings on pure braided Thompson's groups

OpenAIRE

Burillo, Jose; Gonzalez-Meneses, Juan

2006-01-01

In this paper it is proved that the pure braided Thompson’s group BF admits a bi-order, analog to the bi-order of the pure braid groups. Ministerio de Educación y Ciencia Fondo Europeo de Desarrollo Regional

Detection of high mass cluster ions sputtered from Bi surfaces

Energy Technology Data Exchange (ETDEWEB)

Shepard, A; Hewitt, R W; Slusser, G J; Baitinger, W E; Cooks, R G; Winograd, N [Purdue Univ., Lafayette, Ind. (USA). Dept. of Chemistry; Delgass, W N [Purdue Univ., Lafayette, Ind. (USA); Varon, A; Devant, G [Societe RIBER, 92 - Rueil-Malmaison (France)

1976-12-01

The technique of secondary ion mass spectrometry (SIMS) has been employed to detect Bi/sup 3 +/ ions and associated oxides Bi/sub 3/Osub(x)sup(+)(x=1 to 4) from a Bi foil. Using a 3 keV Ar/sup +/ ion primary beam of 5x10/sup -7/ A/cm/sup 2/, mass resolution to nearly 700 with the requisite sensitivity has been achieved. The Bi surface was also monitored by X-ray photoelectron spectroscopy (XPS or ESCA). The presence of a weak O 1s peak at 532.7 eV and a strong SIMS Bi/sup 3 +/ peak is interpreted to mean that the oxygen is weakly incorporated into the Bi lattice without disrupting metal-metal bonds.

Electromotive force measurement of lanthanides in Bi solution

International Nuclear Information System (INIS)

Sheng, Jiawei; Yamana, Hajimu; Moriyama, Hirotake

2000-01-01

The thermodynamic properties of Tb, Dy and Ho dissolved in liquid Bi were determined by the electromotive force (EMF) measurement method. The EMF of the following galvanic cell was measured in the range of 500-800degC over a wide range of solute concentration. Ln(solid)|KCl-LiCl|Ln-Bi (solution) There was observed a linear relationship between the EMFs and the lanthanide (Ln) concentrations in liquid Bi phase at a constant temperature, which agreed with the Nernst's equation. The obtained activity coefficients of lanthanides in liquid Bi solution were almost constant at a fixed temperature condition. Temperature effects on the activity coefficients could be expressed by the following equation: log γ=a+b/T, where a and b are experimental constants which correspond to the entropy and enthalpy of the formation of Ln-Bi compound in the melt, respectively. The thermodynamic quantities obtained were discussed in terms of their systematics along the 4f series. (author)

Bi-Provincial Upgrader

International Nuclear Information System (INIS)

1997-01-01

Husky Oil's Bi-Provincial Upgrader is located in the rural municipality of Wilton, east of Lloydminster, Saskatchewan. It is jointly owned by Husky Oil and the Saskatchewan government. The upgrader is designed to produce 7.300 m 3 /cd of synthetic crude from 8.440 m 3 /cd of diluted Lloyd blend and distillates from the existing Lloydminster refinery. The designed coke and sulphur production is 415 t/day and 240 t/day respectively. Chronology of the Bi-Provincial Upgrader project was presented, along with details of the heavy oil feedstock properties for Cold Lake, Lloydminster and Lloyd Blend. Upgrader production history since start-up, synthetic crude oil customers, and the evolution of prices for Edmonton light vs. Husky LLB at Hardisty were also reviewed. 3 tabs., 9 figs

Fabrication of heterostructured Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} photocatalyst and efficient photodegradation of organic contaminants under visible-light

Energy Technology Data Exchange (ETDEWEB)

Sun, Meng; Li, Shuangli; Yan, Tao; Ji, Pengge; Zhao, Xia; Yuan, Kun; Wei, Dong [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Du, Bin, E-mail: dubin61@gmail.com [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

2017-07-05

Highlights: • The product shows efficient activity in photodegradation of RhB, BPA, and phenol. • The BBOC-10 heterojunction exhibits the best activity under visible light. • Suppressed recombination of photo-generated carriers lead to the activity enhancement. - Abstract: Heterostructured Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} photocatalysts were fabricated by a facile one-pot hydrothermal method, in which melem served as the sacrificial reagent to supply carbonate anions. The as-synthesized Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} heterojunction catalysts were characterized by X-ray diffraction, UV–vis diffuse reflectance spectra, X-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscope. The XRD patterns of Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} catalysts showed the distinctive peaks of Bi{sub 2}O{sub 2}CO{sub 3} and Bi{sub 2}O{sub 4}. The SEM and TEM results showed that the pure Bi{sub 2}O{sub 2}CO{sub 3} possessed large plate morphology, while Bi{sub 2}O{sub 4} were composed of various nanorods and particles. As for Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} heterojunction, it was obviously observed that Bi{sub 2}O{sub 4} nanorods and particles were grown on the surfaces of Bi{sub 2}O{sub 2}CO{sub 3} plates. The visible light driven photocatalytic activity of Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} heterojunction photocatalyst was evaluated by decomposing dyes, phenol, and bisphenol A in water. Compared with Bi{sub 2}O{sub 2}CO{sub 3} and Bi{sub 2}O{sub 4}, the Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} photocatalysts have exhibited remarkable enhanced activity under visible light. The excellent activity can be mainly attributed to the enhanced separation efficiency of photo-generated carriers. Controlled experiments using different radical scavengers proved that ·O{sub 2}{sup −} and h{sup +} played the main role in decomposing organic pollutants. The results of this work would

Factors Influencing BI Data Collection Strategies: An Empirical Investigation

Science.gov (United States)

Ramakrishnan, Thiagarajan

2010-01-01

The purpose of this dissertation is to examine the external factors that influence an organizations' business intelligence (BI) data collection strategy when mediated by BI attributes. In this dissertation, data warehousing strategies are used as the basis on which to frame the exploration of BI data collection strategies. The attributes include…

Bi209 alpha activity

International Nuclear Information System (INIS)

Araujo Penna, M.M. de.

1970-01-01

The study for measuring Bi 209 alpha activity is presented. Ilford L4 nuclear emulsion pellicles loaded with bismuth citrate to obtain a load of 100 mg/cm 3 of dry emulsion, were prepared. Other pellicles were prepared with the same. Ilford L4 gel to estimate the background radiation. To observe 'fading' effect, pellicles loaded with bismuth were submitted to neutrons of high energy, aiming to record recoil proton tracks. The pellicles were confined in nitrogen atmosphere at temperature lower than -10 0 C. The Bi 209 experimental half-life was obtained and compared with the estimated theoretical data. (M.C.K.) [pt

Comportamiento eléctrico del compuesto Bi5FeTi3O15 y de sus soluciones sólidas con CaBi4Ti4O15

Directory of Open Access Journals (Sweden)

Durán, P.

1999-12-01

Full Text Available Bi5FeTi3O15 (BiFT compound has been prepared by solid state reaction between the corresponding oxides. Its crystalline structure has been established by X ray Diffraction, (XRD. Ceramic samples with apparent density > 95% Dth have been sintered. On these samples, electrical conductivity and Curie temperature have been measured. Solid solutions of Bi5FeTi3O15 (BiFT and CaBi4Ti4O15 (CBiT have been prepared. On poled samples of these solid solutions, piezoelectric parameters have been established. The BiFT compound shows electrical conductivity values very similar to those of the Bi4Ti3O12 (BiT compound. The electrical conductivity of solid solutions is a function of CBiT amount. A possible electrical conductivity mechanism which is different of that accepted for the BiT compound is discussed.Se ha preparado Bi5FeTi3O15 (BiFT por reacción en estado sólido de los óxidos correspondientes. Se ha determinado su estructura cristalina por Difracción de Rayos X (DRX. Se han preparado compactos sinterizados con densidades superiores al 95%. Se ha determinado su temperatura de Curie, y la conductividad eléctrica entre 150 y 850ºC. Se han preparado soluciones sólidas de Bi5FeTi3O15 con CaBi4Ti4O15, (CBiT y se han determinado los mismos parámetros de temperatura de Curie y de conductividad para ellas. En las soluciones sólidas se han determinado los parámetros Piezoeléctricos de muestras polarizadas Debe destacarse que el compuesto Bi5FeTi3O15 presenta unos valores de conducción eléctrica más próximos a los correspondientes al Bi4Ti3O12 (BiT que a los de los compuestos MeBi4Ti4O15. La conductividad eléctrica de las soluciones sólidas varía con el contenido de CBiT. Se discute la posible existencia de un modelo de conducción eléctrica que difiere del aceptado hasta el momento para el BiT, basado en los defectos localizados en las capas Bi2O2 2-.

Method of producing superconducting fibers of bismuth strontium calcium copper oxide (Bi(2212) and Bi(2223))

Science.gov (United States)

Schwartzkopf, Louis A.

1991-10-01

Fibers of Bi(2212) have been produce by pendant drop melt extraction. This technique involves the end of a rod of Bi(2212) melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 15 cm in length with the usual lateral dimensions, ranging from 20 um to 30 um. The fibers require a heat treatment to make them superconducting.

29 CFR 2.13 - Audiovisual coverage prohibited.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Audiovisual coverage prohibited. 2.13 Section 2.13 Labor Office of the Secretary of Labor GENERAL REGULATIONS Audiovisual Coverage of Administrative Hearings § 2.13 Audiovisual coverage prohibited. The Department shall not permit audiovisual coverage of the...

A federal tax credit to encourage employers to offer health coverage.

Science.gov (United States)

Meyer, J A; Wicks, E K

2001-01-01

Many firms that employ low-wage workers cannot afford to offer an employee health plan, and many of the uninsured work for such firms. This article makes the case for an employer tax credit, administered by the Internal Revenue Service, as a way to extend health coverage to uninsured workers and their families. The permanent, fixed-dollar, refundable credit would be available to all low-wage employers (those with average wages of $10 per hour and less), including those already offering coverage. The credit would be graduated depending on average wage: the maximum credit would equal 50% of the cost of a standard benefit package; the minimum would equal 30% of the package. It also would vary by family size and could be used to cover part-time and temporary workers. Participating employers would be required to pay at least 50% of the health insurance premium, proof of which would be shown on firms' tax returns. The paper provides justification for this approach. It closes with a discussion of strengths and weaknesses of this approach and alternative design features.

Bi-Polaron Condensation in High Tc Superconductors

International Nuclear Information System (INIS)

Ranninger, J.

1995-01-01

On the basis of optical measurements-, photoemission-, EXAFS- and neutron scattering-experiments we conclude that itinerant valence electrons coexist with localized bi-polarons.Entering the metallic phase upon chemical doping, a charge transfer between the two electronic subsystems is triggered off. We show that as the temperature is lowered towards Tc this process leads to a delocalization of bi-polarons due to a precursor effect of superfluidity of those bi-polarons. Upon entering the superconducting phase, these bipolarons ultimately condense into a superfluid state which is expected to largely determine the superconducting properties of high Tc materials. (authors)

Red emission enhancement from CaMoO4:Eu3+ by co-doping of Bi3+ for near UV/blue LED pumped white pcLEDs: Energy transfer studies

Science.gov (United States)

Wangkhem, Ranjoy; Yaba, Takhe; Shanta Singh, N.; Ningthoujam, R. S.

2018-03-01

CaMoO4:Eu3+ (3 at. %)/Bi3+ (x at. %) nanophosphors were synthesized hydrothermally. All the samples can be excited by 280, 320, 393, and 464 nm (blue) wavelengths for generation of red color emission. Enhancement in 5D0 → 7F2 (615 nm) emission (f-f transition) of Eu3+ is observed when Bi3+ is incorporated in CaMoO4:Eu3+. This is due to the efficient energy transfer from Bi3+ to Eu3+ ions. Introduction of Bi3+ in the system does not lead to the change of emission wavelength of Eu3+. However, Bi3+ incorporation in the system induces a shift in Mo-O charge transfer band absorption from 295 to 270 nm. This may be due to the increase in electronegativity between Mo and O bond in the presence of Bi3+ leading to change in crystal field environment of Mo6+ in MoO42-. At the optimal concentration of Bi3+, an enhancement in emission by a factor of ˜10 and 4.2 in the respective excitation at 393 (7F0 → 5L6) and 464 nm (7F0 → 5D2) is observed. The energy transfer efficiency from Bi3+ to Eu3+ increases from 75% to 96%. The energy transfer is observed to occur mainly via dipole-dipole interactions. Maximum quantum yield value of 55% is observed from annealed CaMoO4:Eu3+ (3 at. %) when sensitized with Bi3+ (15 at. %) under 464 nm excitation. From Commission International de I'Eclairage chromaticity coordinates, the color (red) saturation is observed to be nearly 100%.

Dosimetric comparison of standard bi-dimensional radiotherapy, mono-isocentric three-dimensional and arc-therapy for a bilateral breast cancer case with ganglionary attack; Comparaison dosimetrique pour un cas de cancer du sein bilateral avec atteinte ganglionnaire de la radiotherapie bidimensionnelle standard, la radiotherapie tridimensionnelle mono-isocentrique et l'arctherapie

Energy Technology Data Exchange (ETDEWEB)

Arnaud, A. [Centre Leon-Berard, Lyon (France); Bodez, V.; Alric, K.; Chastel, D.; Mege, A. [Institut Sainte-Catherine, Avignon (France)

2011-10-15

The authors report a study which aimed at determining the optimal radiotherapy technique for a patient operated from a bilateral breast cancer with ganglionary attack and peculiar thoracic conformation. A dosimetric study has been performed. Target volumes and lung and heart coverages have been compared for three techniques: bi-dimensional and three-dimensional radiotherapy, and arc-therapy. It appears that arc-therapy would allow a dosimetric and therapeutic duration gain without improving the target volume coverage while increasing doses delivered to organs at risk. Short communication

INTERVAL-VALUED INTUITIONISTIC FUZZY BI-IDEALS IN TERNARY SEMIRINGS

Directory of Open Access Journals (Sweden)

D. KRISHNASWAMY

2016-04-01

Full Text Available In this paper we introduce the notions of interval-valued fuzzy bi-ideal, interval-valued anti fuzzy bi-ideal and interval-valued intuitionistic fuzzy bi-ideal in ternary semirings and some of the basic properties of these ideals are investigated. We also introduce normal interval-valued intuitionistic fuzzy ideals in ternary semirings.

Effect of surface modification of BiFeO3 on the dielectric, ferroelectric, magneto-dielectric properties of polyvinylacetate/BiFeO3 nanocomposites

Directory of Open Access Journals (Sweden)

O. P. Bajpai

2014-09-01

Full Text Available Bismuth ferrite (BiFeO3 is considered as one of the most promising materials in the field of multiferroics. In this work, a simple green route as well as synthetic routes has been used for the preparation of pure phase BiFeO3. An extract of Calotropis Gigantea flower was used as a reaction medium in green route. In each case so formed BiFeO3 particles are of comparable quality. These particles are in the range of 50–60 nm and exhibit mixed morphology (viz., spherical and cubic as confirmed by TEM analysis. These pure phase BiFeO3 nanoparticles were first time surface modified effectively by mean of two silylating agent’s viz., tetraethyl orthosilicate (TEOS and (3-Aminopropyltriethoxysilane (APTES. Modified and unmodified BiFeO3 nanoparticles were efficiently introduced into polyvinylacetate (PVAc matrix. It has been shown that nanocomposite prepared by modified BiFeO3 comprise superior dispersion characteristics, improved ferroelectric properties and favorable magneto-dielectric properties along with excellent wettability in compare to nanocomposite prepared by unmodified BiFeO3. These preliminary results demonstrate possible applications of this type of nanocomposites particularly in the field of multiferroic coating and adhesives.

Observations of a bi-directional lightning leader producing an M-component

Science.gov (United States)

Kotovsky, D. A.; Uman, M. A.; Wilkes, R.; Carvalho, F. L.; Jordan, D. M.

2017-12-01

Lightning discharges to ground often exhibit millisecond-scale surges in the continuing currents following return strokes, called M-components. Relatively little is known regarding the source of M-component charge and the mechanisms by which that charge is transferred to ground. In this work, we seek to directly address these questions by presenting correlated high-speed video and Lightning Mapping Array (LMA) observations of a bi-directional leader that resulted in an M-component occurring in a rocket-and-wire triggered lightning flash. The observed leader initiated in the decayed remnants of a positive leader channel that had traversed virgin air approximately 90 msec prior. Three-dimensional locations and speeds of the photographed bi-directional leader and M-component processes are calculated by mapping video images to the observed LMA channel geometry. Both ends of the bi-directional leader exhibited speeds on the order of 2 x106 m sec-1 over 570 meters of the visible channel. Propagation of the luminosity wave from the in-cloud leader to ground ( 8.8 km channel length) exhibited appreciable dispersion, with rise-times (10-90%) increasing from 330 to 410 μsec and pulse-widths (half-maximum) increasing from 380 to 810 μsec - the M-component current pulse measured at ground-level exhibited a rise-time of 290 μsec and a pulse-width of 770 μsec. Group velocities of the luminosity wave have been calculated as a function of frequency, increasing from 2 x107 to 6 x107 m sec-1 over the dominant signal bandwidth (DC to 2 kHz). Additionally, multiple waves of luminosity are observed within the in-cloud channel, indicating nuanced wave phenomena possibly associated with reflection from the end of the leader channel and attachment with the main lightning channel carrying continuing current to ground.

Piezoelectric power converter with bi-directional power transfer

DEFF Research Database (Denmark)

2014-01-01

The present invention relates to a bi-directional piezoelectric power converter com¬ prising a piezoelectric transformer. The piezoelectric transformer comprises an input electrode electrically coupled to a primary section of the piezoelectric transformer and an output electrode electrically...... coupled to an output section of the piezoelectric transformer to provide a transformer output signal. A bi-directional switching circuit is coupled between the output electrode and a DC or AC output voltage of the power converter. Forward and reverse current conducting periods of the bi......, a reverse current is conducted through the bi-directional switching circuit from the DC or AC output voltage to the output electrode to discharge the DC or AC output voltage and return power to the primary section of the piezoelectric transformer....

Optical properties of a new Bi{sub 38}Mo{sub 7}O{sub 78} semiconductor with fluorite-type δ-Bi{sub 2}O{sub 3} structure

Energy Technology Data Exchange (ETDEWEB)

Wang, Zuoshan; Bi, Shala; Wan, Yingpeng [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Huang, Pengjie [College of Textile and Clothing Engineering, Soochow University, Suzhou 215006 (China); Zheng, Min, E-mail: zhengmin@suda.edu.cn [College of Textile and Clothing Engineering, Soochow University, Suzhou 215006 (China)

2017-03-31

Highlights: • Bi{sub 38}Mo{sub 7}O{sub 78} semiconductor nanoparticles were synthesized by sol-gel method. • Bi{sub 38}Mo{sub 7}O{sub 78} keeps the structural characteristics of the patrimonial δ-Bi{sub 2}O{sub 3} structure. • Bi{sub 38}Mo{sub 7}O{sub 78} show an efficient optical absorption in visible light. • Photocatalytic property was markedly enhanced for Bi{sub 38}Mo{sub 7}O{sub 78} nanoparticles. • The mechanism of this photocatalysis system was proposed. - Abstract: Bi{sup 3+}-containing inorganic materials usually show rich optical and electronic properties due to the hybridization between 6s and 6p electronic components together with the lone pair in Bi{sup 3+} ions. In this work, a new semiconductor of bismuth molybdate Bi{sub 38}Mo{sub 7}O{sub 78} (19Bi{sub 2}O{sub 3}·7MoO{sub 3}) was synthesized by the sol-gel film coating and the following heat process. The samples developed into nanoparticles with average size of 40 nm. The phase formation was verified via the XRD Rietveld structural refinement. Orthorhombic Bi{sub 38}Mo{sub 7}O{sub 78} can be regarded to be derived from the cubic δ-phase Bi{sub 2}O{sub 3} structure. The microstructure was investigated by SEM, EDX, TEM, BET and XPS measurements. The UV-vis absorption spectra showed that the band gap of Bi{sub 38}Mo{sub 7}O{sub 78} (2.38 eV) was greatly narrowed in comparison with Bi{sub 2}O{sub 3} (2.6 eV). This enhances the efficient absorption of visible light. Meanwhile, the conduction band of is wider and shows more dispersion, which greatly benefits the mobility of the light-induced charges taking part in the photocatalytic reactions. Bi{sub 38}Mo{sub 7}O{sub 78} nanoparticles possess efficient activities on the photodegradation of methylene blue (MB) solutions under the excitation of visible-light. The photocatalysis activities and mechanisms were discussed on the crystal structure characteristics and the measurements such as photoluminescence, exciton lifetime and XPS results.

BiCaSrCuO superconductors

International Nuclear Information System (INIS)

Polvi, V.M.; Niemi, K.J.

1989-01-01

BiCaSrCuO and BiPbCaSrCuO powders have been synthesized. Different research methods (SEM,EDS,XRF,SRD,DTA) have been used to characterize the bulk specimen and wires. Resistance and current density measured as a function of temperature are reported. The ceramic products contained several phases. Lead containing specimen gave the best results and the synthesis was easily reproducible

Spatial-temporal Evolution of Vegetation Coverage and Analysis of it’s Future Trends in Wujiang River Basin

Science.gov (United States)

Xiao, Jianyong; Bai, Xiaoyong; Zhou, Dequan; Qian, Qinghuan; Zeng, Cheng; Chen, Fei

2018-01-01

Vegetation coverage dynamics is affected by climatic, topography and human activities, which is an important indicator reflecting the regional ecological environment. Revealing the spatial-temporal characteristics of vegetation coverage is of great significance to the protection and management of ecological environment. Based on MODIS NDVI data and the Maximum Value Composites (MVC), we excluded soil spectrum interference to calculate Fractional Vegetation Coverage (FVC). Then the long-term FVC was used to calculate the spatial pattern and temporal variation of vegetation in Wujiang River Basin from 2000 to 2016 by using Trend analysis and Hurst index. The relationship between topography and spatial distribution of FVC was analyzed. The main conclusions are as follows: (1) The multi-annual mean vegetation coverage reveals a spatial distribution variation characteristic of low value in midstream and high level in other parts of the basin, owing a mean value of 0.6567. (2) From 2000 to 2016, the FVC of the Wujiang River Basin fluctuated between 0.6110 and 0.7380, and the overall growth rate of FVC was 0.0074/a. (3) The area of vegetation coverage tending to improve is more than that going to degrade in the future. Grass land, Arable land and Others improved significantly; karst rocky desertification comprehensive management project lead to persistent vegetation coverage improvement of Grass land, Arable land and Others. Residential land is covered with obviously degraded vegetation, resulting of urban sprawl; (4) The spatial distribution of FVC is positively correlated with TNI. Researches of spatial-temporal evolution of vegetation coverage have significant meaning for the ecological environment protection and management of the Wujiang River Basin.

Bi-cooperative games in bipolar fuzzy settings

Czech Academy of Sciences Publication Activity Database

Hazarika, P.; Borkotokey, S.; Mesiar, Radko

2018-01-01

Roč. 47, č. 1 (2018), s. 51-66 ISSN 0308-1079 Institutional support: RVO:67985556 Keywords : Bi-cooperative games * bipolar fuzzy bi-coalition * Shapley function Subject RIV: BA - General Mathematics Impact factor: 2.490, year: 2016 http://library.utia.cas.cz/separaty/2018/E/mesiar-0485377.pdf

42 CFR 440.330 - Benchmark health benefits coverage.

Science.gov (United States)

2010-10-01

...) Federal Employees Health Benefit Plan Equivalent Coverage (FEHBP—Equivalent Health Insurance Coverage). A... coverage. Health benefits coverage that is offered and generally available to State employees in the State... 42 Public Health 4 2010-10-01 2010-10-01 false Benchmark health benefits coverage. 440.330 Section...

Stark broadening of several Bi IV spectral lines of astrophysical interest

Science.gov (United States)

Colón, C.; Moreno-Díaz, C.; de Andrés-García, I.; Alonso-Medina, A.

2017-09-01

The presence of spectral lines of bismuth in stellar atmospheres has been reported in different stars. The anomalous values of the spectral intensities of Bi II and Bi III, compared to the theoretical Local Termodinamic Equilibrium (LTE) standards of Bi I/Bi II/Bi III, have been reported in the spectra obtained with the High Resolution Spectrograph of the Hubble/Goddard Space Telescope in the chemically peculiar stars HgMn stars χ Lupi and HR 7775. Spectral lines of 1436.8, 1902.3, 2630.9 and 2936.7 Å of Bi II and 1423.4 Å of Bi III were reported and their relative intensities were measured in these studies Litzén & Wahlgren 2002. These lines are overlapped with spectral lines of 1437.65, 2630.1 and 2937.1 Å of Bi IV. A study of the Stark broadening parameters of Bi IV spectral lines can help to study these overlaps. In this paper, using the Griem semi-empirical approach, we report calculated values of the Stark parameters for 64 spectral lines of Bi IV. The matrix elements used in these calculations have been determined from 17 configurations of Bi IV. They were calculated using the cowan code including core polarization effects. Data are displayed for an electron density of 1017 cm-3 and temperatures T = 10 000-160 000 K. Also calculated radiative lifetimes for 12 levels with experimental lifetime are presented, in order to test the goodness of our calculations. Theoretical trends of the Stark width and shift parameters versus the temperature for spectral lines of astrophysical interest are displayed.

Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2}){sub x}F (x=1 and 2): New one-dimensional Bi-coordination materials-Reversible hydration and topotactic decomposition to {alpha}-Bi{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Jeon, Hye Rim [Department of Chemistry Education, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Lee, Dong Woo [Department of Chemistry, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Ok, Kang Min, E-mail: kmok@cau.ac.kr [Department of Chemistry, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

2012-03-15

Two one-dimensional bismuth-coordination materials, Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2}){sub x}F (x=1 and 2), have been synthesized by hydrothermal reactions using Bi{sub 2}O{sub 3}, 2,6-NC{sub 5}H{sub 3}(CO{sub 2}H){sub 2}, HF, and water at 180 Degree-Sign C. Structures of the two materials were determined by single-crystal X-ray diffraction. Although they have different crystal structures, both Bi-organic materials shared a common structural motif, a one-dimensional chain structure consisting of Bi{sup 3+} cations and pyridine dicarboxylate linkers. Detailed structural analyses include infrared spectroscopy, thermogravimetric analysis, and reversible hydration reactions for the coordinated water molecules were reported. Also, thermal decomposition of the rod-shaped Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2})F single crystals at 800 Degree-Sign C led to {alpha}-Bi{sub 2}O{sub 3} that maintained the same morphology of the original crystals. - Graphical abstract: Calcination of the Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2})F single crystals at 800 Degree-Sign C results in the {alpha}-Bi{sub 2}O{sub 3} rods that maintain the original morphology of the crystals. Highlights: Black-Right-Pointing-Pointer Synthesis of one-dimensional chain Bi-organic frameworks. Black-Right-Pointing-Pointer Reversible hydration reactions of Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2})F. Black-Right-Pointing-Pointer Topotactic decomposition maintaining the same morphology of the original crystals.

Antigen-presenting cells exposed to Lactobacillus acidophilus NCFM, Bifidobacterium bifidum BI-98, and BI-504 reduce regulatory T cell activity

DEFF Research Database (Denmark)

Schmidt, Esben Gjerløff Wedebye; Claesson, Mogens Helweg; Jensen, Simon Skjøde

2010-01-01

BACKGROUND:: The effect in vitro of six different probiotic strains including Lactobacillus acidophilus NCFM, Lactobacillus salivarius Ls-33, Lactobacillus paracasei subsp. paracasei YS8866441, Lactobacillus plantarum Lp-115, Bifidobacterium bifidum BI-504 and BI-98 was studied on splenic...

New structural and electrical data on Bi-Mo mixed oxides with a structure based on [Bi12O14]∞ columns

International Nuclear Information System (INIS)

Vannier, R.N.; Abraham, F.; Nowogrocki, G.; Mairesse, G.

1999-01-01

The authors recently described a new family of oxide anion conductors with a structure based on [Bi 12 O 14 ] ∞ columns (Journal of Solid State Chemistry 122, 394 (1996)). The parent compound of this series can be formulated as Bi 26 Mo 10 O 69 and formation of a solid solution, in the Bi 2 O 3 -MoO 3 binary system, in the range 2.57 ≤ Bi/Mo ≤ 2.77 was established. The stoichiometry of this series was questioned by R. Enjalbert et al. (Journal of Solid State Chemistry 131, 236 (1997)), but confirmed by D.J. Buttrey et al. (Materials Research Bulletin 32, 947 (1997)). The first part of this paper is devoted to a refutation of criticisms by R. Enjalbert et al. In the second part, a comparison with other Bi 2 O 3 -based oxide anion conductors enables the authors to propose an iono-covalent description of this novel structure type, taking into account all the structural and electrical features, especially new neutron powder diffraction refinement and conductivity measurements under variable oxygen partial pressures

Thermoelectric transport properties of BaBiTe{sub 3}-based materials

Energy Technology Data Exchange (ETDEWEB)

Zhou, Yiming; Zhao, Li-Dong, E-mail: zhaolidong@buaa.edu.cn

2017-05-15

BaBiTe{sub 3}, a material with low thermal conductivity, is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. We choose two types of dopants, K and La, trying to optimize its electrical transport properties. The minority carriers, which harm the Seebeck coefficient in this system, are suppressed by La doping. With the increase of both electrical conductivity and Seebeck coefficient, the power factor of 3% La doped BaBiTe{sub 3} reaches 3.7 μW cm{sup −1} K{sup −2} which increased by 40% from undoped BaBiTe{sub 3}. Besides high power factor, the thermal conductivity is also reduced in it. Eventually, a high ZT value, 0.25 at 473 K, for n-type BaBiTe{sub 3} is achieved in 3% La doped BaBiTe{sub 3}. - Graphical abstract: BaBiTe{sub 3} possesses a low thermal conductivity. However, it is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. A high ZT value of 0.25 at 473 K for n-type BaBiTe{sub 3} can be achieved through optimizing electrical transport properties via La doping. - Highlights: • BaBiTe{sub 3} is an analogue of these promising thermoelectric materials: such as CsBi{sub 4}Te{sub 6} and K{sub 2}Bi{sub 8}Se{sub 13}, etc. • BaBiTe{sub 3} possesses a low thermal conductivity. • La is an effective dopant to enhance electrical transport properties. • A high ZT value of 0.25 at 473 K can be achieved in n-type La-doped BaBiTe{sub 3}.

Convenient hydrothermal decomposition process for preparation of nanocrystalline mineral Cu3BiS3 and Pb1-xBi2x/3S

International Nuclear Information System (INIS)

Hu Junqing; Deng Bin; Wang Chunrui; Tang Kaibin; Qian Yitai

2003-01-01

Mineral nanocrystalline Cu 3 BiS 3 and Pb 1-x Bi 2x/3 S (or Bi 0.22 Pb 0.89 S 1.22 ) have been prepared at low synthetic temperature of 100-150 deg. C by convenient hydrothermal decomposition process. X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectra, and element analysis were used to characterize and measure the samples. The as-prepared Cu 3 BiS 3 sample consisted of whisker-like particles with an average size of 50x10 nm 2 and the Pb 1-x Bi 2x/3 S sample displayed aggregative particles with size in the range of 30-50 nm. Preliminary results showed that the prepared precursors, reaction temperature and time played a role in the formation of the final products. A possible reaction mechanism was also discussed briefly

Solidification of Bi2Sr2Ca1Cu2Oy and Bi2Sr1.75Ca0.25CuOy

International Nuclear Information System (INIS)

Holesinger, T.G.; Miller, D.J.; Viswanathan, H.K.; Chumbley, L.S.

1993-01-01

The solidification processes for the compositions Bi 2 Sr 2 CaCu 2 O y (2212) and Bi 2 Sr 1.75 Ca 0.25 CuO y (2201) were determined as a function of oxygen partial pressure. During solidification in argon, the superconducting phases were generally not observed to form for either composition. In both cases, the solidus is lowered to approximately 750 degree C. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 2-x Ca x O y (22x) and Cu 2 O while solidification of Bi 2 Sr 2 CaCu 2 O y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 3-x Ca x O y (23x) and Cu 2 O. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in O 2 resulted in large grains of 2201 interspersed with small regions containing the eutectic structure of 22x and CuO/Cu 2 O. Solidification of Bi 2 Sr 2 CaCu 2 O y in partial pressures of 1%, 20%, and 100% oxygen resulted in multiphase samples consisting of 2212, 2201, some alkaline-earth cuprates, and both divorced eutectic structures found during solidification in Ar. For both compositions, these latter structures can be attributed to oxygen deficiencies present in the melt regardless of the overpressure of oxygen. These eutectic structures are unstable and convert into the superconducting phases during subsequent anneals in oxygen. The formation process of the 2212 phase during solidification from the melt was determined to proceed through an intermediate state involving the 2201 phase

SU-E-T-174: Evaluation of the Optimal Intensity Modulated Radiation Therapy Plans Done On the Maximum and Average Intensity Projection CTs

Energy Technology Data Exchange (ETDEWEB)

Jurkovic, I [University of Texas Health Science Center at San Antonio, San Antonio, TX (United States); Stathakis, S; Li, Y; Patel, A; Vincent, J; Papanikolaou, N; Mavroidis, P [Cancer Therapy and Research Center University of Texas Health Sciences Center at San Antonio, San Antonio, TX (United States)

2014-06-01

Purpose: To determine the difference in coverage between plans done on average intensity projection and maximum intensity projection CT data sets for lung patients and to establish correlations between different factors influencing the coverage. Methods: For six lung cancer patients, 10 phases of equal duration through the respiratory cycle, the maximum and average intensity projections (MIP and AIP) from their 4DCT datasets were obtained. MIP and AIP datasets had three GTVs delineated (GTVaip — delineated on AIP, GTVmip — delineated on MIP and GTVfus — delineated on each of the 10 phases and summed up). From the each GTV, planning target volumes (PTV) were then created by adding additional margins. For each of the PTVs an IMRT plan was developed on the AIP dataset. The plans were then copied to the MIP data set and were recalculated. Results: The effective depths in AIP cases were significantly smaller than in MIP (p < 0.001). The Pearson correlation coefficient of r = 0.839 indicates strong degree of positive linear relationship between the average percentage difference in effective depths and average PTV coverage on the MIP data set. The V2 0 Gy of involved lung depends on the PTV coverage. The relationship between PTVaip mean CT number difference and PTVaip coverage on MIP data set gives r = 0.830. When the plans are produced on MIP and copied to AIP, r equals −0.756. Conclusion: The correlation between the AIP and MIP data sets indicates that the selection of the data set for developing the treatment plan affects the final outcome (cases with high average percentage difference in effective depths between AIP and MIP should be calculated on AIP). The percentage of the lung volume receiving higher dose depends on how well PTV is covered, regardless of on which set plan is done.

40 CFR 51.356 - Vehicle coverage.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Vehicle coverage. 51.356 Section 51.356....356 Vehicle coverage. The performance standard for enhanced I/M programs assumes coverage of all 1968 and later model year light duty vehicles and light duty trucks up to 8,500 pounds GVWR, and includes...

Structural and electronic properties of low-index stoichiometric BiOI surfaces

Energy Technology Data Exchange (ETDEWEB)

Dai, Wen-Wu; Zhao, Zong-Yan, E-mail: zzy@kmust.edu.cn

2017-06-01

As promising photocatalyst driven by visible-light, BiOI has attracted more and more attention in the past years. However, the surface structure and properties of BiOI that is the most important place for the photocatalytic have not been investigated in details. To this end, density functional theory was performed to calculate the structural and electronic properties of four low-index stoichiometric surfaces of BiOI. It is found that the relaxation of the low-index BiOI surfaces are relatively small, especially the (001) surface. Thus, the surface energies of BiOI are very relatively small. Moreover, there are a few surface states below the bottom of conduction band in the first layer except the (001) surface, which maybe capture the photo-excited carriers. In all of the most stable terminated planes, all the dangling bonds are cleaved from the broken Bi-O bonds. In the case of (001) surface, the dangling bond density of Bi atoms for the (001) surface is zero per square nano. Therefore, the (001) surface is thermodynamically lowest-energy surface of BiOI, and it is the predominant surface (51.4%). As a final remark, the dangling bonds density of bismuth atoms determines not only the surface energy, but also the surface relaxation. Finally, the equilibrium morphology of BiOI was also proposed and provided, which is determined through the Wulff construction. These results will help us to better understand the underlying photocatalytic mechanism that is related to BiOI surfaces, and provide theoretical support for some experimental studies about BiOI-based photocatalyst in future. - Highlights: • Four low-index BiOI surfaces have been calculated by DFT method. • The relaxations of the low-index BiOI surfaces are relatively small. • There are a few surface states below the bottom of conduction band in the first layer. • The dangling bonds density of bismuth atoms determines not only the surface energy, but also the surface relaxation. • The thermodynamic

Photocatalytic Performance of a Novel MOF/BiFeO3 Composite

Directory of Open Access Journals (Sweden)

Yunhui Si

2017-10-01

Full Text Available In this study, MOF/BiFeO3 composite (MOF, metal-organic framework has been synthesized successfully through a one-pot hydrothermal method. The MOF/BiFeO3 composite samples, pure MOF samples and BiFeO3 samples were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, and by UV–vis spectrophotometry. The results and analysis reveal that MOF/BiFeO3 composite has better photocatalytic behavior for methylene blue (MB compared to pure MOF and pure BiFeO3. The enhancement of photocatalytic performance should be due to the introduction of MOF change the surface morphology of BiFeO3, which will increase the contact area with MB. This composing strategy of MOF/BiFeO3 composite may bring new insight into the designing of highly efficient photocatalysts.

Decay studies of a long lived high spin isomer of 210Bi

International Nuclear Information System (INIS)

Tuggle, D.G.

1976-08-01

A source of approximately 30 μg of pure (> 90%) /sup 210m/Bi (Jπ = 9-) was prepared by irradiating 209 Bi in a nuclear reactor. After chemical separations to remove 210 Po from the irradiated bismuth sample were completed, the 210 Bi was electromagnetically separated from the 209 Bi by a series of two isotope separations to create the source mentioned above. This source was then used to conduct alpha, conversion electron, gamma, gamma-gamma coincidence, and alpha-gamma coincidence spectroscopic studies of the decay of /sup 210m/Bi. The partial half life for the alpha decay of /sup 210m/Bi was measured as 3.0 x 10 6 yr. A lower limit of 10 13 years was set for the partial half life for the decay of /sup 210m/Bi to 210 Po. Alpha decay of /sup 210m/Bi to 8 excited states of 206 Tl was observed. A lower limit of 10 -4 % was set for the branching ratio of the parity forbidden alpha decay of 210 Bi to the 206 Ti ground state. Theoretical decay rates for the alpha decays of /sup 210m/Bi, 210 Bi, 211 Po, and /sup 211m/Po were calculated using the method developed by Hans Mang. A comparison of the calculated and experimentally measured alpha decay rates of /sup 210m/Bi showed good agreement for the relative alpha decay rates

Targeting SR-BI for cancer diagnostics, imaging and therapy

Directory of Open Access Journals (Sweden)

Maneesha Amrita Rajora

2016-09-01

Full Text Available Scavenger receptor class B type I (SR-BI plays an important role in trafficking cholesteryl esters between the core of high density lipoprotein and the liver. Interestingly, this integral membrane protein receptor is also implicated in the metabolism of cholesterol by cancer cells, whereby overexpression of SR-BI has been observed in a number of tumours and cancer cell lines, including breast and prostate cancers. Consequently, SR-BI has recently gained attention as a cancer biomarker and exciting target for the direct cytosolic delivery of therapeutic agents. This brief review highlights these key developments in SR-BI-targeted cancer therapies and imaging probes. Special attention is given to the exploration of high density lipoprotein nanomimetic platforms that take advantage of upregulated SR-BI expression to facilitate targeted drug-delivery and cancer diagnostics, and promising future directions in the development of these agents.

Constructing nanoporous carbon nanotubes/Bi2Te3 composite for synchronous regulation of the electrical and thermal performances

Science.gov (United States)

Zhang, Qihao; Xu, Leilei; Zhou, Zhenxing; Wang, Lianjun; Jiang, Wan; Chen, Lidong

2017-02-01

Porous nanograined thermoelectric materials exhibit low thermal conductivity due to scattering of phonons by pores, which are favorable for thermoelectric applications. However, the benefit is not large enough to overcome the deficiency in the electrical performance. Herein, an approach is presented to reduce the thermal conductivity and synchronously enhance the electrical conductivity through constructing a nanoporous thermoelectric composite. Carbon nanotubes (CNTs) are truncated and homogeneously dispersed within the Bi2Te3 matrix by a cryogenic grinding (CG) technique for the first time, which efficiently suppress the Bi2Te3 grain growth and create nanopores with the size ranging from dozens to hundreds of nanometers. The lattice thermal conductivity is substantially decreased by broad wavelength phonon scattering resulting from nanopores, increased grain boundaries, and newly formed interfaces. Meanwhile, the electrical conductivity is improved due to the enhanced carrier mobility, which may originate from the bridging effect between the Bi2Te3 grains and CNTs. The maximum ZT is improved by almost a factor of 2 due to the simultaneous optimization of electrical and thermal performances. Our study demonstrates the superiority of constructing a bulk thermoelectric composite with nanopores by the uniform dispersion of CNTs through a CG technique for enhanced thermoelectric properties, which provides a wider approach to thermoelectric nanostructure engineering.

Thermodynamics of Bi2O3-SiO2 system

Directory of Open Access Journals (Sweden)

Onderka B.

2017-01-01

Full Text Available Thermodynamic properties of the liquid Bi2O3-SiO2 solutions were determined from the results of the electrochemical measurements by use of the solid oxide galvanic cells with YSZ (Yttria-Stabilized-Zirconia electrolyte. Activities of Bi2O3 in the solutions were determined for 0.2, 0.3, 0.4, and 0.5 SiO2 mole fractions in the temperature range 1073-1293 K from measured electromotive force (e.m.f of the solid electrolyte galvanic cell: Bi, Bi2O3-SiO2 | YSZ | air (pO2 = 0.213 bar Additionally, heat capacity data obtained for two solid phases 6Bi2O3•SiO2 and 2Bi2O3•3SiO2 were included into optimization of thermodynamic properties of the system. Optimization procedure was supported by differential thermal analysis (DTA data obtained in this work as well as those accepted from the literature. Using the data obtained in this work, and the information about phase equilibria found in the literature, binary system Bi2O3-SiO2 was assessed with the ThermoCalc software.

A study of the formation processes of the 2212 phase in the Bi-based superconductor systems. [BiSrCaCuO

Energy Technology Data Exchange (ETDEWEB)

Wai, Lo; Glowacki, B A [Interdisciplinary Research Centre in Superconductivity, Univ. of Cambridge (United Kingdom)

1992-04-15

A study towards the identification of the reactions contributing to and accompanying the formation of the 2212 phase from oxides and carbonates by solid state reaction processes was conducted. The formation processes were investigated by thermal analysis, powder X-ray diffractometry and AC magnetic susceptometry. The 2212 phase was found to form from reactions between the 2201 phases (the non-superconducting pseudo-tetragonal and the superconducting monoclinic phases), Bi{sub 6}Ca{sub 7}O{sub 16}, CuO and SrCO{sub 3}. The 2201 phases were produced by the reactions of Bi-Sr-Cu-O or Bi-Sr-O compounds with SrCO{sub 3} or CuO. The 2201 phases could also be formed through the direct reaction between Bi{sub 2}CuO{sub 4} and SrCO{sub 3}. (orig.).

Electron diffraction study of the sillenites Bi{sub 12}SiO{sub 20}, Bi{sub 25}FeO{sub 39} and Bi{sub 25}InO{sub 39}: Evidence of short-range ordering of oxygen-vacancies in the trivalent sillenites

Energy Technology Data Exchange (ETDEWEB)

Scurti, Craig A.; Arenas, D. J. [Department of Physics, University of North Florida, Jacksonville, FL 32224 (United States); Auvray, Nicolas [Department of Physics, University of North Florida, Jacksonville, FL 32224 (United States); Laboratoire de Nanotechnologie et d’Instrumentation Optique - UMR CNRS 6279, Université Technologie de Troyes, 12 rue Marie Curie, Troyes 10010 (France); Lufaso, Michael W. [Department of Chemistry, University of North Florida, Jacksonville, FL 32224 (United States); Takeda, Seiji [The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Kohno, Hideo [School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kami, Kochi 782-8502 Japan (Japan)

2014-08-15

We present an electron diffraction study of three sillenites, Bi{sub 12}SiO{sub 20}, Bi{sub 25}FeO{sub 39}, and Bi{sub 25}InO{sub 39} synthesized using the solid-state method. We explore a hypothesis, inspired by optical studies in the literature, that suggests that trivalent sillenites have additional disorder not present in the tetravalent compounds. Electron diffraction patterns of Bi{sub 25}FeO{sub 39} and Bi{sub 25}InO{sub 39} show streaks that confirm deviations from the ideal sillenite structure. Multi-slice simulations of electron-diffraction patterns are presented for different perturbations to the sillenite structure - partial substitution of the M site by Bi{sup 3+}, random and ordered oxygen-vacancies, and a frozen-phonon model. Although comparison of experimental data to simulations cannot be conclusive, we consider the streaks as evidence of short-range ordered oxygen-vacancies.

Tri-maximal vs. bi-maximal neutrino mixing

International Nuclear Information System (INIS)

Scott, W.G

2000-01-01

It is argued that data from atmospheric and solar neutrino experiments point strongly to tri-maximal or bi-maximal lepton mixing. While ('optimised') bi-maximal mixing gives an excellent a posteriori fit to the data, tri-maximal mixing is an a priori hypothesis, which is not excluded, taking account of terrestrial matter effects

Bi-metallic catalysts, methods of making, and uses thereof

KAUST Repository

Basset, Jean-Marie

2017-01-19

Provided herein are bi-metallic catalysts, methods of making, and uses thereof. In some embodiments, the bi-metallic catalyst contains two different metal catalysts that can be used in hydrocarbon metathesis reactions, in some embodiments, the methods of making the bi-metallic catalysts can include two steps utilizing a surface organometallic chemistry approach in which the two different metal catalysts are sequentially grafted onto a support.

Bi-metallic catalysts, methods of making, and uses thereof

KAUST Repository

Basset, Jean-Marie; Samantaray, Manoja K.; Dey, Raju; Abou-Hamad, Edy; Kavitake, Santosh

2017-01-01

Provided herein are bi-metallic catalysts, methods of making, and uses thereof. In some embodiments, the bi-metallic catalyst contains two different metal catalysts that can be used in hydrocarbon metathesis reactions, in some embodiments, the methods of making the bi-metallic catalysts can include two steps utilizing a surface organometallic chemistry approach in which the two different metal catalysts are sequentially grafted onto a support.

Investigation on magnetoelectric behavior of (80Bi0.5Na0.5TiO3-20Bi0.5K0.5TiO3)-CoFe2O4 particulate composites

Science.gov (United States)

Liu, Sheng; Yan, Shuoqing; Yao, Lingling; He, Jun; He, Longhui; Hu, Zhaowen; Huang, Shengxiang; Deng, Lianwen

2017-12-01

Particulate magnetoelectric (ME) ceramics constituted by (1-x)(80Bi0.5Na0.5TiO3-20Bi0.5K0.5TiO3)-xCoFe2O4 [(1-x)BNKT-xCFO] (x = 0, 0.1, 0.2, 0.3, 0.4 and 1.0) were synthesized by an powder-in-sol precursor hybrid processing method and their structure, magnetic, ferroelectric, magnetodielectric (MD) and ME properties have been investigated. Results showed that the ceramics consisted of only two chemically separated phases and had homogeneous microstructure. The introduction of CFO into BNKT matrix led to the weakening of ferroelectric and dielectric properties whereas the strengthening magnetic and MD properties. The observation of the MD effect revealed the evidence of the strain-induced ME coupling and the MD value is well scaled with M2. A maximum value of ME output of 25.07 mV/cm·Oe was achieved for the 0.7BNKT-0.3CFO composite. The improved ME response together with the linear MD effect makes the ceramics promise for use in magnetic field controllable devices or magneto-electric transducers.

Analysis of the residual strain change of Bi2212, Ag alloy and Ag during the heating and cooling process in Bi2212/Ag/Ag alloy composite wire

International Nuclear Information System (INIS)

Shin, J K; Ochiai, S; Okuda, H; Mukai, Y; Sugano, M; Sato, M; Oh, S S; Ha, D W; Kim, S C

2008-01-01

The residual strain change of Bi2212 and Ag during the cooling and heating process in the Bi2212/Ag/Ag alloy composite superconductor was studied. First, the residual strain of Bi2212 filaments at room temperature was measured by the x-ray diffraction method. Then, the Young's moduli of the constituents (Bi2212 filaments, Ag and Ag alloy) and yield strains of Ag and Ag alloy were estimated from the analysis of the measured stress-strain curve, based on the rule of mixtures. Also, the coefficient of thermal expansion of the Bi2212 filaments was estimated from the analysis of the measured thermal expansion curve of the composite wire. From the modeling analysis using the estimated property values and the residual strain of Bi2212 filaments, the changes of residual strain of Bi2212, Ag alloy and Ag with temperature during the cooling and heating process were revealed

Insurance Coverage Policies for Personalized Medicine

Directory of Open Access Journals (Sweden)

Andrew Hresko

2012-10-01

Full Text Available Adoption of personalized medicine in practice has been slow, in part due to the lack of evidence of clinical benefit provided by these technologies. Coverage by insurers is a critical step in achieving widespread adoption of personalized medicine. Insurers consider a variety of factors when formulating medical coverage policies for personalized medicine, including the overall strength of evidence for a test, availability of clinical guidelines and health technology assessments by independent organizations. In this study, we reviewed coverage policies of the largest U.S. insurers for genomic (disease-related and pharmacogenetic (PGx tests to determine the extent that these tests were covered and the evidence basis for the coverage decisions. We identified 41 coverage policies for 49 unique testing: 22 tests for disease diagnosis, prognosis and risk and 27 PGx tests. Fifty percent (or less of the tests reviewed were covered by insurers. Lack of evidence of clinical utility appears to be a major factor in decisions of non-coverage. The inclusion of PGx information in drug package inserts appears to be a common theme of PGx tests that are covered. This analysis highlights the variability of coverage determinations and factors considered, suggesting that the adoption of personal medicine will affected by numerous factors, but will continue to be slowed due to lack of demonstrated clinical benefit.

Spatial variations in composition in high-critical-current-density Bi-2223 tapes

International Nuclear Information System (INIS)

Holesinger, T. G.; Bingert, J. F.; Teplitsky, M.; Li, Q.; Parrella, R.; Rupich, M. P.; Riley, G. N. Jr.

2000-01-01

A detailed compositional analysis of high-critical-current-density (J c ) (55 and 65 kA/cm2 at 77 K) (Bi, Pb) 2 Sr 2 Ca 2 Cu 3 O y (Bi-2223) tapes was undertaken by energy dispersive spectroscopy in the transmission electron microscope. Structural features were coupled with characteristic compositions of the Bi-2223 phase. The average of all compositional measurements of the Bi-2223 phase was determined to be Bi 1.88 Pb 0.23 Sr 1.96 Ca 1.95 Cu 2.98 O y . However, spatial variations in the Bi-2223 composition and differing phase equilibria were found throughout the filament structure. In particular, a considerable range of Bi-2223 compositions can be found within a single tape, and the lead content of the Bi-2223 phase is significantly depressed in the vicinity of lead-rich phases. The depletion of lead in the Bi-2223 phase around the 3221 phases may be a current-limiting microstructure in these tapes. (c) 2000 Materials Research Society

Carbon dots/BiOCl films with enhanced visible light photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Lin, Weitian; Yu, Xiang; Shen, Yinghua; Chen, Hongbin; Zhu, Yi, E-mail: tzhury@jnu.edu.cn; Zhang, Yuanming [Jinan University, Department of Chemistry (China); Meng, Hui [Jinan University, Siyuan laboratory, Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Department of Physics (China)

2017-02-15

Novel carbon dots with a diameter of 6 nm modified BiOCl (CDs/BiOCl) photocatalyst on FTO was synthesized via a facile immobilization method at room temperature. The crystalline structures, morphologies, optical properties, and photocatalytic properties were studied. The results showed that the CDs/BiOCl films exhibited higher photocatalytic activity than pure BiOCl. The 4 wt% CDs/BiOCl film showed the best photocatalytic activity, which was about eight times than that of pure BiOCl and excellent recyclability even after four recycles. Compared with other film photocatalysts, the photocatalytic activity of 4 wt% CDs/BiOCl was also higher than that of many other photocatalysts. The enhanced activity was ascribed to the enhanced light adsorption and the improvement of charge separation. Holes and superoxide radicals ·O{sub 2}{sup −} were revealed as the dominant reactive species. The photocatalytic mechanism was proposed based on the results.

Processing of bulk Bi-2223 high-temperature superconductor

Directory of Open Access Journals (Sweden)

Alexander Polasek

2005-12-01

Full Text Available The Bi2Sr2Ca2Cu3 O10+x (Bi-2223 is one of the main high temperature superconductors for applications. One of these applications is the Superconductor Fault Current Limiter (SCFCL, which is a very promising high temperature superconducting device. SCFCL's can be improved by using bulk superconductors with high critical currents, which requires a sufficiently dense and textured material. In the present work, a process for improving the microstructure of Bi-2223 bulk samples is investigated. Pressed precursor blocks are processed by sintering with a further partial melting step, in order to enhance the Bi-2223 grain texture and to healing cracks induced by pressing. In order to improve the microstructure, the precursor is mixed with silver powder before pressing. Samples with and without silver powder have been studied, with the aim of investigating the influence of silver on the microstructure evolution. The phase contents and the microstructure obtained have been analyzed through XRD and SEM/EDS. The electromagnetic characterization has been performed by Magnetic Susceptibility Analysis. We present and discuss the process and the properties of the superconducting blocks. High fractions of textured Bi-2223 grains have been obtained.

The Crystal Structure of Cu4Bi4Se9

DEFF Research Database (Denmark)

Makovicky, E.; Søtofte, Inger; Karup-Møller, S.

2002-01-01

contains three square pyramidal Bi sites, an octahedrally coordinated Bi site as well as two tetrahedrally and two irregularly coordinated Cu sites. The structure is an intergrowth of PbS-like slabs with irregularly configured slabs of Bi pyramids and Cu tetrahedra. It contains covalently bonded Se-2...

[Comparative double-blind study of Bi-Profenid and oxyphenbutazone in sports pathology].

Science.gov (United States)

Commandré, F A; Fornaris, E; Fourré, J M; Raybaud, A; Colonna, P; Pirdas, C

1983-12-12

Effectiveness and tolerance of ketoprofen in sustained-release tablets (Bi-Profenid 150 mg) were investigated in a double blind trial in 44 athletes who had recently sprained an ankle. Patients were given either 300 mg Bi-Profenid or 400 mg oxyphenbutazone daily for seven days. Treatment regimens were assigned at random. Results were assessed as excellent or good in 85% of patients given Bi-Profenid and 50% of those given oxyphenbutazone. Spontaneous pain resolved in 19 patients receiving Bi-Profenid and in 6 under oxyphenbutazone. Decrease in pain upon physical examination and in articular circumference was significantly greater with Bi-Profenid as compared with oxyphenbutazone. The chance of rapidly resuming sport was better with Bi-Profenid. Tolerance was excellent in 68.2% of patients with Bi-Profenid and 59% of those with oxyphenbutazone. This investigation thus emphasizes the value of Bi-Profenid in sport pathology.

The crystal structure of Cu1.78Bi4.73Se8, an N=3 pavonite homologue with a Cu-for-Bi substitution

DEFF Research Database (Denmark)

Makovicky, Emil; Søtofte, Inger; Karup-Møller, Sven

2006-01-01

Abstract: Cu1.78Bi4.73Se8, synthesized in a dry phase system Cu-Bi-Se at 450 degrees C, is monoclinic, a = 13.759 angstrom, b = 4.168 angstrom, c = 14.683 angstrom, beta = 115.61 degrees, space group C2/m. It is an N = 3 member of the pavonite homologous series, with the composition limits Cu1.96Bi...

Photoelectrochemical Performance Observed in Mn-Doped BiFeO3 Heterostructured Thin Films

Directory of Open Access Journals (Sweden)

Hao-Min Xu

2016-11-01

Full Text Available Pure BiFeO3 and heterostructured BiFeO3/BiFe0.95Mn0.05O3 (5% Mn-doped BiFeO3 thin films have been prepared by a chemical deposition method. The band structures and photosensitive properties of these films have been investigated elaborately. Pure BiFeO3 films showed stable and strong response to photo illumination (open circuit potential kept −0.18 V, short circuit photocurrent density was −0.023 mA·cm−2. By Mn doping, the energy band positions shifted, resulting in a smaller band gap of BiFe0.95Mn0.05O3 layer and an internal field being built in the BiFeO3/BiFe0.95Mn0.05O3 interface. BiFeO3/BiFe0.95Mn0.05O3 and BiFe0.95Mn0.05O3 thin films demonstrated poor photo activity compared with pure BiFeO3 films, which can be explained by the fact that Mn doping brought in a large amount of defects in the BiFe0.95Mn0.05O3 layers, causing higher carrier combination and correspondingly suppressing the photo response, and this negative influence was more considerable than the positive effects provided by the band modulation.

Exchange coupling in permalloy/BiFeO3 heterostructures

Science.gov (United States)

Heron, John; Wang, Chen; Carlton, David; Nowakowski, Mark; Gajek, Martin; Awschalom, David; Bokor, Jeff; Ralph, Dan; Ramesh, R.

2010-03-01

BiFeO3 is a ferroelectric and antiferromagnetic multiferroic with the ferroelectric and antiferromagnetic order parameters coupled at room temperature. This coupling results in the reorientation of the ferroelectric and magnetic domains as applied voltages switch the electric polarization. Previous studies using ferromagnet/BiFeO3 heterostructures have shown that the anisotropy of the ferromagnetic layer can be tuned by the ferroelectric domain structure of the BiFeO3 film [1, 2]. The physical mechanism driving this exchange bias with BiFeO3 is still under investigation. We use patterned permalloy structures, with varying aspect ratios, on BiFeO3 thin films to investigate the physics of this interaction. The results of our studies using MFM, PEEM, and MOKE to understand this mechanism as a means to electric field control of magnetic structures will be presented. [4pt] [1] H. Bea et al., Physical Review Letters 100, 017204 (2008).[0pt] [2] L.W. Martin et al., Nanoletters 8, 2050 (2008).

One pot hydrothermal synthesis of a novel BiIO4/Bi2MoO6 heterojunction photocatalyst with enhanced visible-light-driven photocatalytic activity for rhodamine B degradation and photocurrent generation

International Nuclear Information System (INIS)

Huang, Hongwei; Liu, Liyuan; Zhang, Yihe; Tian, Na

2015-01-01

Graphical abstract: The efficient charge transfer occurred at the interface of BiIO 4 /Bi 2 MoO 6 heterojunction results in the efficient separation of photoexcited electron–hole pairs and promotes the photocatalytic activity. - Highlights: • BiIO 4 /Bi 2 MoO 6 composites were synthesized by a one-step hydrothermal method. • The BiIO 4 /Bi 2 MoO 6 composite exhibits much better photoelectrochemical performance. • The highly improved photocatalytic activity is attributed to heterojunction structure. • Holes (h + ) are the main active species in the photodegradation process of RhB. - Abstract: A novel BiIO 4 /Bi 2 MoO 6 heterojunction photocatalyst has been successfully developed by a one-step hydrothermal method for the first time. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and diffuse reflection spectroscopy (DRS). Compared to pure BiIO 4 and Bi 2 MoO 6 , the BiIO 4 /Bi 2 MoO 6 composite exhibits the much better photoelectrochemical performance for Rhodamine B (RhB) degradation and photocurrent (PC) generation under visible light irradiation (λ > 420 nm). This enhancement on visible-light-responsive photocatalytic activity should be attributed to the fabrication of a BiIO 4 /Bi 2 MoO 6 heterojunction, thus resulting in the high separation and transfer efficiency of photogenerated charge carriers. The supposed photocatalytic mechanism dominated by holes (h + ) was verified by the photoluminescence (PL) spectroscopy, electrochemical impedance spectra (EIS) and active species trapping experiments

Multilocational evaluation of white yam genotypes using GGE bi-plot ...

African Journals Online (AJOL)

Five new white yam genotypes were evaluated in different locations of major yam producing areas; Umudike, Nsukka, Ubiaja, Abuja and Katsina-Ala, to test the performance and stability of these genotypes across the environments using GGE bi-plot software. The GGE bi-plot generated several graphic bi-plots which ...

Non-noble metal Bi deposition by utilizing Bi2WO6 as the self-sacrificing template for enhancing visible light photocatalytic activity

Science.gov (United States)

Yu, Shixin; Zhang, Yihe; Li, Min; Du, Xin; Huang, Hongwei

2017-01-01

Bi metal deposited on Bi2WO6 composite photocatalysts have been successfully synthesized via a simple in-situ reduction method at room temperature with using Bi2WO6 as self-sacrificing template and NaBH4 as reducing agent. The reduction extent can be easily modulated by controlling the concentration of NaBH4 solution. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) spectra, N2 adsorption-desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), diffuse reflection spectroscopy (DRS) and photoelectrochemical measurements were carried out to analyze the phase, morphology, optical property and photoelectrochemical property of the as-prepared samples. The photocatalytic activity is surveyed by degradation of phenol under visible light (λ > 420 nm), which showed that the BWO-0.2 photocatalyst exhibited the highest efficiency, which was over 3 times as high as pure Bi2WO6. The enhanced photocatalytic activity should be attributed to strengthened photoabsorption and charge separation efficiency derived from the surface plasmon resonance (SPR) of Bi metal.

Synthesis of belt-like BiOBr hierarchical nanostructure with high photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Li, Haiping [National Engineering Technology Research Center for Colloidal Materials, Shandong University, Jinan 250100 (China); Liu, Jingyi; Hu, Tingxia [Environment Research Institute, Shandong University, Jinan 250100 (China); Du, Na; Song, Shue [Key Laboratory of Colloid and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100 (China); Hou, Wanguo, E-mail: wghou@sdu.edu.cn [Key Laboratory of Colloid and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100 (China)

2016-05-15

Highlights: • BiOBr hierarchical nanobelts (NBs) were solvothermally prepared. • NBs show higher specific surface area and photoabsorption than BiOBr nanosheets. • NBs exhibit higher photoactivity than the nanosheets. - Abstract: One-dimensional (1D) bismuth oxyhalide (BiOX) hierarchical nanostructures are always difficult to prepare. Herein, we report, for the first time, a simple synthesis of BiOBr nanobelts (NBs) via a facile solvothermal route, using bismuth subsalicylate as the template and bismuth source. The BiOBr nanobelts are composed of irregular single crystal nanoparticles with highly exposed (0 1 0) facets. Compared with the BiOBr nanosheets (NSs) with dominant exposed (0 0 1) facets, they exhibit higher photocatalytic activity toward degradation of Rhodamine B and Methylene Blue under visible light irradiation. The higher photocatalytic performance of BiOBr NBs arises from their larger specific surface area and higher photoabsorption capability. This study provides a simple route for synthesis of belt-like Bi-based hierarchical nanostructures.

Angle-resolved-photoemission study of Bi2Sr2CaCu2O8+δ: Metallicity of the Bi-O plane

International Nuclear Information System (INIS)

Wells, B.O.; Shen, Z.; Dessau, D.S.; Spicer, W.E.; Olson, C.G.; Mitzi, D.B.; Kapitulnik, A.; List, R.S.; Arko, A.

1990-01-01

We have performed high-resolution angle-resolved-photoemission experiments on Bi 2 Sr 2 CaCu 2 O 8+δ single crystals with different annealing histories. By depositing a small amount of Au on the surface, we were able to distinguish electronic states associated with the Bi-O surface layer. We found that the Bi-O atomic surface layer is metallic and superconducting for samples that were high-temperature annealed in oxygen but not for as-grown samples. The Cu-O plane is found to be superconducting in all samples

Solvothermal synthesis and analysis of Bi1-xSbx nanoparticles

International Nuclear Information System (INIS)

Sumithra, S.; Misra, D.K.; Wei, C.; Gabrisch, H.; Poudeu, P.F.P.; Stokes, K.L.

2011-01-01

Bismuth-antimony alloy nanoparticles have been synthesized by a facile solvothermal method using N,N-dimethylformamide and ethylene glycol as solvent/reducing agent; BiCl 3 , SbCl 3 and Bi(NO 3 ) 3 as precursors; and citric acid as a surface modifier/stabilizing agent. The particle size and size distribution of Bi nanoparticles were analyzed as a function of the synthesis conditions: molar ratio of precursor to surfactant, precursor concentration and reducing agent. Synthesis of Sb and Bi 0.88 Sb 0.12 under similar conditions was also investigated. The phase purity of nanoparticles was confirmed from X-ray diffraction and thermogravimetry and the nanoparticle morphology was investigated by transmission electron microscopy. A case study of Bi nanoparticles with detailed analysis of the particle morphology and size distribution of the nanoparticles is reported.

Percent Coverage

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Percent Coverage is a spreadsheet that keeps track of and compares the number of vessels that have departed with and without observers to the numbers of vessels...

Characterization of standard reference material 2944, Bi-ion-doped glass, spectral correction standard for red fluorescence

International Nuclear Information System (INIS)

DeRose, Paul C.; Smith, Melody V.; Anderson, Jeffrey R.; Kramer, Gary W.

2013-01-01

Standard Reference Material (SRM) 2944 is a cuvette-shaped, Bi-ion-doped glass, recommended for optimal use for relative spectral correction of emission from 590 nm to 805 nm and day-to-day performance verification of steady-state fluorescence spectrometers. Properties of this standard that influence its effective use or contribute to the uncertainty in its certified emission spectrum were explored here. These properties include its photostability, absorbance, dissolution rate in water, anisotropy and temperature coefficient of fluorescence intensity. The expanded uncertainties (k=2) in the certified spectrum are about 4% around the nominal peak maximum at 704 nm and increase to about 6% at the wings, using an excitation wavelength of 515 nm. -- Highlights: ► The fluorescence emission spectrum of SRM 2944 was determined for spectral correction. ► This Bi-ion-doped glass has been certified in the fluorescence region from 530 nm to 830 nm. ► Fluorescence properties of the glass were determined, e.g., anisotropy, lifetime. ► SRM 2944 is photostable under common visible lamp excitation, when UV light is not present

Comparison of Danish dichotomous and BI-RADS classifications of mammographic density.

Science.gov (United States)

Hodge, Rebecca; Hellmann, Sophie Sell; von Euler-Chelpin, My; Vejborg, Ilse; Andersen, Zorana Jovanovic

2014-06-01

In the Copenhagen mammography screening program from 1991 to 2001, mammographic density was classified either as fatty or mixed/dense. This dichotomous mammographic density classification system is unique internationally, and has not been validated before. To compare the Danish dichotomous mammographic density classification system from 1991 to 2001 with the density BI-RADS classifications, in an attempt to validate the Danish classification system. The study sample consisted of 120 mammograms taken in Copenhagen in 1991-2001, which tested false positive, and which were in 2012 re-assessed and classified according to the BI-RADS classification system. We calculated inter-rater agreement between the Danish dichotomous mammographic classification as fatty or mixed/dense and the four-level BI-RADS classification by the linear weighted Kappa statistic. Of the 120 women, 32 (26.7%) were classified as having fatty and 88 (73.3%) as mixed/dense mammographic density, according to Danish dichotomous classification. According to BI-RADS density classification, 12 (10.0%) women were classified as having predominantly fatty (BI-RADS code 1), 46 (38.3%) as having scattered fibroglandular (BI-RADS code 2), 57 (47.5%) as having heterogeneously dense (BI-RADS 3), and five (4.2%) as having extremely dense (BI-RADS code 4) mammographic density. The inter-rater variability assessed by weighted kappa statistic showed a substantial agreement (0.75). The dichotomous mammographic density classification system utilized in early years of Copenhagen's mammographic screening program (1991-2001) agreed well with the BI-RADS density classification system.

Ion-cyclotron instability in plasmas described by product-bi-kappa distributions

International Nuclear Information System (INIS)

Santos, M. S. dos; Ziebell, L. F.; Gaelzer, R.

2015-01-01

The dispersion relation for parallel propagating waves in the ion-cyclotron branch is investigated numerically by considering that the velocity distribution of the ion population is a function of type product-bi-kappa. We investigate the effects of the non-thermal features and of the anisotropy associated with this type of distribution on the ion-cyclotron instability, as well as the influence of different forms of the electron distribution, by considering Maxwellian distributions, bi-kappa distributions, and product-bi-kappa distributions. The cases of ions described by either Maxwellian or bi-kappa distributions are also considered, for comparison. The results of the numerical analysis show that the increase in the non-thermal character associated with the anisotropic kappa distributions for ions contributes to enhance the instability as compared to that obtained in the Maxwellian case, in magnitude and in wave number range, with more significant enhancement for the case of ion product-bi-kappa distributions than for the case of ion bi-kappa distributions. It is also shown that the ion-cyclotron instability is decreased if the electrons are described by product-bi-kappa distributions, while electrons described by bi-kappa distributions lead to growth rates which are very similar to those obtained considering a Maxwellian distribution for the electron population

Fe-doping effect on the Bi{sub 3}Ni superconductor microstructure

Energy Technology Data Exchange (ETDEWEB)

Gonsalves, Silvio Henrique; Monteiro, Joao Frederico Haas Leandro; Leal, Adriane Consuelo da Silva; Andrade, Andre Vitor Chaves de; Souza, Gelson Biscaia de; Siqueira, Ezequiel Costa; Serbena, Francisco Carlos; Jurelo, Alcione Roberto, E-mail: arjurelo@uepg.br [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Departamento de Fisica

2017-05-15

The substitution effects of Fe ion on the structure of the intermetallic Bi{sub 3}Ni{sub 1-x}Fe{sub x} (0 ≤ x ≤ 0.10) superconductor were studied. The morphology of samples consists of an inhomogeneous laminar slab-like microstructure. The main phase corresponds to Bi{sub 3}Ni{sub 1-x}Fe{sub x} with an orthorhombic structure (Pnma), but with very small quantities of impurities of BiNi and Bi as revealed by X-ray diffraction. SEM and AFM reveal that the Bi3{sub N}i1{sub -x}Fe{sub x} phase consists of two regions. One region is Bi richer and Ni and Fe poorer than the other region.Raman spectroscopy revealed two phonon modes at room temperature. No significant changes were observed in the spectra with Fe doping and in different regions of the Bi{sub 3}Ni{sub 1-x}Fe{sub x} phase. Superconductivity is observed below a transition temperature T{sub C} = 4 K and regardless of iron doping. (author)

Thermodynamic study of the rich-Bi2O3 region of the Bi2O3-ZnO system

Directory of Open Access Journals (Sweden)

de la Rubia, M. A.

2006-06-01

Full Text Available Precise knowledge of the Bi2O3-ZnO system is fundamental to control the functional microstructure of ZnO-based varistors. Also the potential applications of materials based on ZnO and Bi2O3 as dielectric materials in the high frequency range have renewed the interest in this binary system. The aim of the present work is to carry out a thermodynamic analysis of the Bi2O3-ZnO phase diagram, taking into account the existing experimental information. Thermodynamic calculation has been performed according CALPHAD methodology (CALculation of PHAse Diagrams, using the software Thermo-Calc.El conocimiento preciso del sistema Bi2O3-ZnO es una herramienta básica para conseguir el control de la microestructura de los varistores basados en ZnO. Recientemente otros materiales basados en óxidos de cinc y bismuto han mostrado un gran potencial para su uso en aplicaciones como dieléctricos a frecuencias altas, renovando el interés por dicho sistema binario. El objetivo del presente trabajo es realizar una evaluación termodinámica del diagrama de fases consistente para el sistema Bi2O3-ZnO teniendo en cuenta la información experimental existente del mismo. La evaluación termodinámica del sistema se ha llevado a cabo mediante la metodología CALPHAD (CALculation of PHAse Diagrams, empleando el software Thermo- Calc.

Sorghum bi-color

African Journals Online (AJOL)

sunny

2014-11-12

Nov 12, 2014 ... Biomass materials require reduction and densification for the purpose of handling and space requirements. Guinea corn (Sorghum bi-color) is a major source of biomass material in the tropic regions. The densification process involves some ... a closed-end die, the temperature and the use of binder.

Performance analysis of bi-directional broadband passive optical network using erbium-doped fiber amplifier

Science.gov (United States)

Almalaq, Yasser; Matin, Mohammad A.

2014-09-01

The broadband passive optical network (BPON) has the ability to support high-speed data, voice, and video services to home and small businesses customers. In this work, the performance of bi-directional BPON is analyzed for both down and up streams traffic cases by the help of erbium doped fiber amplifier (EDFA). The importance of BPON is reduced cost. Because PBON uses a splitter the cost of the maintenance between the providers and the customers side is suitable. In the proposed research, BPON has been tested by the use of bit error rate (BER) analyzer. BER analyzer realizes maximum Q factor, minimum bit error rate, and eye height.

Providing Universal Health Insurance Coverage in Nigeria.

Science.gov (United States)

Okebukola, Peter O; Brieger, William R

2016-07-07

Despite a stated goal of achieving universal coverage, the National Health Insurance Scheme of Nigeria had achieved only 4% coverage 12 years after it was launched. This study assessed the plans of the National Health Insurance Scheme to achieve universal health insurance coverage in Nigeria by 2015 and discusses the challenges facing the scheme in achieving insurance coverage. In-depth interviews from various levels of the health-care system in the country, including providers, were conducted. The results of the analysis suggest that challenges to extending coverage include the difficulty in convincing autonomous state governments to buy into the scheme and an inadequate health workforce that might not be able to meet increased demand. Recommendations for increasing the scheme's coverage include increasing decentralization and strengthening human resources for health in the service delivery systems. Strong political will is needed as a catalyst to achieving these goals. © The Author(s) 2016.

SO2 frost - UV-visible reflectivity and Io surface coverage

Science.gov (United States)

Nash, D. B.; Fanale, F. P.; Nelson, R. M.

1980-01-01

The reflectance spectrum in the range 0.24-0.85 microns of SO2 frost is measured in light of the discovery of SO2 gas in the atmosphere of Io and the possible discovery of the frost on its surface. Frost deposits up to 1.5 mm thick were grown in vacuum at 130 K and bi-directional reflectance spectra were obtained. Typical SO2 frost is found to exhibit very low reflectivity (2-5%) at 0.30 microns, rising steeply at 0.32 microns to attain a maximum reflectivity (75-80%) at 4.0 microns and uniformly high reflectivity throughout the visible and near infrared. Comparison with the full disk spectrum of Io reveals that no more than 20% of the surface can be covered with optically thick SO2 frost. Combinations of surface materials including SO2 frost which can produce the observed spectrum are indicated.

BiOSS: A system for biomedical ontology selection.