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Letteratura scientifica selezionata sul tema "CALCIUM BISMUTH"

Autore: Grafiati

Pubblicato: 16 settembre 2023

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Articoli di riviste sul tema "CALCIUM BISMUTH"

Ryabov, A. V. "New Medium-Carbon Free-Machining Steels Containing Bismuth and Calcium". Materials Science Forum 843 (febbraio 2016): 101–5. http://dx.doi.org/10.4028/www.scientific.net/msf.843.101.

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The paper describes the properties of two new medium-carbon free-machining alloy structural steels. These steels are environmentally friendly since lead in them is replaced with much less harmful elements bismuth and calcium. Bismuth and calcium are rather uniformly distributed in the ingot, though there are two zones of bismuth heterogeneity in the bottom and in the head part of the ingot. Mechanical properties of steels are at the same level as for steels without bismuth and calcium. Non-metallic inclusion content is typical for structural steels melted in open electric arc furnaces with basic lining and is not changed by the presence of bismuth and calcium. Machinability of the steels with bismuth and calcium is at the same or higher level than that of lead-bearing steels. Melting, casting, forging and rolling of steel containing bismuth and calcium is not associated with working area air-pollution with harmful substances in amounts exceeding maximum permissible concentrations. During rolling of the lead-free steels harmful emissions are almost absent, unlike the lead-bearing steels.

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Ryabov, A. V., Aleksandr A. Dyakonov e M. G. Vakhitov. "A New Free-Machining Steel Containing Bismuth and Calcium". Materials Science Forum 857 (maggio 2016): 251–55. http://dx.doi.org/10.4028/www.scientific.net/msf.857.251.

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The paper presents a new environmentally friendly lead-free free-machining structural steel AVTs19KhGN containing bismuth and calcium. The following quality characteristics of the new steel (in as-cast and forged condition) are determined: mechanical properties; austenite grain size; amount of non-metallic inclusions; surface quality. In forged rods (square 20 mm) a tendency towards an increase of bismuth content is observed from bottom to top of the ingot. Calcium distribution along the billet is uniform. Surface quality of billets in heats following the test heats is comparable to that of analog steels. Austenite grain size does not exceed ASTM number 6. Austenite grain is refined with increasing bismuth content. Mechanical properties are at the same level as for the steel without bismuth and calcium.

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Luo, Feng Chao, Jin Liang He, Jun Hu e Yuan Hua Lin. "Influence of Slight Bismuth Additive on the Properties of Calcium Copper Titanate Ceramic". Advanced Materials Research 105-106 (aprile 2010): 274–77. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.274.

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The CaCu3Ti4O12 samples with slight amount of doped bismuth were prepared and tested in this research. No second phase with bismuth was found in the doped samples. It was inferred that the bismuth ions has entered the lattice and take the place of the calcium ions. The grain size was diminished with the increase of the bismuth content. The bismuth atoms can inhibit the grains from growing large, and it could be used to modify the microstructure of CaCu3Ti4O12 ceramic. The reduction of the grain size resulted in the decrease of the relative dielectric constant, according to the “internal barrier layer capacitance (IBLC)” theory. The impedance measurements showed that the doped samples have less conductivity and lower potential barrier at the grain boundaries, and the substitution of the bismuth ions on the calcium cites might be the reason for it. As a result of the lowered potential barrier, the non-ohmic I-V property of the CaCu3Ti4O12 ceramic almost disappears in the doped ones.

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Pei, Z., A. van Dijken, A. Vink e G. Blasse. "Luminescence of calcium bismuth vanadate (CaBiVO5)". Journal of Alloys and Compounds 204, n. 1-2 (febbraio 1994): 243–46. http://dx.doi.org/10.1016/0925-8388(94)90098-1.

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Ryabov, A. V. "Environmental Aspects of Lead-Free Free-Machining Steels Production". Materials Science Forum 843 (febbraio 2016): 231–35. http://dx.doi.org/10.4028/www.scientific.net/msf.843.231.

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The paper presents the results of comparative studies of working area air pollution during the production of three alloy steels containing bismuth and calcium as machinability-enhancing additives: AVTs40Kh13 (0.4 %C + 13 %Cr + Bi + Ca), AVTs14Kh17N2 (0.14 %C + 17 %Cr + 2 %Ni + Bi + Ca) and AVTs19KhGN (0.19 %C + 0.9 %Mn + 0.9 %Cr + 0.9 %Ni + Bi + Ca). Experimental studies were performed in industrial conditions at Zlatoust Electrometallurgical Plant, Ltd. According to the technology developed and used at the enterprise, bismuth was introduced in the form of shot to the steel stream during casting of 0.5 t ingots at a special casting site. Air samples (of statistically reliable volume) were taken using standard techniques in the working areas at principal moments of technological processes. Bismuth content in air samples was then determined by polarography method. The results demonstrate that bismuth introduction to the steel stream during top casting results in bismuth concentration in the air of the working areas exceeding the maximum permissible concentration of 0.5 mg/m3 only in the first 10 min after casting start. Bottom casting and hot forming of free-machining steels containing bismuth and calcium is not accompanied by pollution of the air in the working area with harmful substances in amounts exceeding maximum permissible concentration, unlike leaded free-machining steels.

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Ryabov, A. V. "Comparative Characteristics of Free-Machining Steels of Cr-Mo Type". Solid State Phenomena 299 (gennaio 2020): 670–75. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.670.

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The work investigates the properties of lead-free free-machining steel grade A30KhMAR, containing BN inclusions, in comparison with the base Cr-Mo steel 30KhM, lead-bearing AS30KhM, lead-calcium-bearing ASTs30KhM, calcium-bearing ATs30KhM, bismuth-calcium-bearing AVTs30KhM and tin-bearing AО30KhM. Effect of bismuth, calcium, lead, tin and boron nitride inclusions on steel susceptibility to temper brittleness and cold brittleness is studied. Contamination of steels with non-metallic inclusions is estimated. End-quench hardenability curves of the test steel A30KhMAR are obtained. Free-machining Cr-Mo structural steel, containing low-melting elements, has ASTM grain size of the number of 7–8. Hardenability and austenite grain size are satisfactory compared to the base steel 30KhM. Mechanical properties of the test steel in longitudinal direction (ultimate and proof stress, specific elongation, reduction in area, impact toughness, hardness) were also determined. It was found that bismuth, calcium, lead, tin, boron and nitrogen (in the form of boron nitride inclusions) within the studied limits do not have negative effect on mechanical properties of heat-treated ASTs30KhM, ATs30KhM, AVTs30KhM, A30KhMAR and AО30KhM steels, and the values of strength, plasticity and toughness characteristics satisfy the requirements of GOST standards for the base steel 30KhM and lead-bearing steel AS30KhM.

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Trokiner, A., L. Le Noc, A. Yakubovskii, K. N. Mykhalyov e S. V. Verkhovskii. "43Ca NMR Study of Bismuth-Based High-Tc Superconductors". Zeitschrift für Naturforschung A 49, n. 1-2 (1 febbraio 1994): 373–78. http://dx.doi.org/10.1515/zna-1994-1-255.

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Abstract As a first step of a study of the electronic properties of CuO2 planes by probing calcium nuclei in the bismuth-based high-Tc materials we report here the structural assignment of Ca NMR lines measured in 43Ca-enriched samples of n = 2 ((Bi,Pb)2Sr2CaCu2O8+x) and n = 3 ((Bi,Pb)2Sr2-Ca2Cu3O10+x) bismuth compounds. Powdered samples were investigated as well as oriented pow ders, achieved by uniaxial alignment of the grains in a 7T magnetic field. For the main calcium site (Ca between two CuO2 planes), we could determine the quadrupolar as well as the shift tensors. The results indicate that, in the same way as yttrium nuclei in YBaCuO, calcium nuclei are sensitive to the magnetic susceptibility of the metallic CuO2 planes.

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Szalbot, Diana, Małgorzata Adamczyk, Beata Wodecka-Duś, Jolanta Dzik, Michał Rerak e Kamil Feliksik. "Influence of calcium doping on microstructure, dielectric and electric properties of BaBi2Nb2O9 ceramics". Processing and Application of Ceramics 12, n. 2 (2018): 171–79. http://dx.doi.org/10.2298/pac1802171s.

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Barium bismuth niobiate (BaBi2Nb2O9) ceramics modified by calcium were prepared by solid state synthesis and two-step sintering process. An impact of calcium substitution on the A site of perovskite block is presented. The investigations are focused on dielectric as well as electric aspects of the modification. The presented results reveal that the concentration of a space charge is not preserved, what is surprising due to the homovalent nature of the dopant and no reason for creating additional lattice defects and charges connected. However, not only the valence of ions, but also the calcium-oxygen and barium-oxygen bond strength should be taken into consideration. Since the calcium-oxygen bond is probably weaker the loss of the bismuth oxide is expected to increase with an increase in the calcium content. Such a scenario results in appearance of a large number of negative charge carriers connected with unsaturated oxygen ions.

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Mubeen, M., e M. Anis-ur-Rehman. "Cerium Doped Bismuth Based High T_c Superconductor: Synthesis and Study of Superconducting Properties". Key Engineering Materials 510-511 (maggio 2012): 75–79. http://dx.doi.org/10.4028/www.scientific.net/kem.510-511.75.

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High-Tcsuperconductivity has been an emerging field for researchers since its discovery. Bismith based superconductors commonly called BSCCO have great importance among the superconducting family. It is divided into three phases among them 2223 phase is highly studied in order to investigate its superconducting properties by substitution of different elements. We have studied the substitution of cerium (Ce) on calcium site of bismuth based Bi (Pb)Sr (Ba)-2223 high-Tcsuperconductor. The nominal compositions of Bi1.6Pb0.4Sr1.6Ba0.4(Ca1-xCex)2Cu3Oxceramic superconductor were prepared by wet chemical method. Stoichiometric amounts of Bi2O3, PbO, Sr (NO3)2, BaCO3, CaCO3, CuO and CeO2were used as starting materials. Structural analysis was done by X-ray diffraction (XRD) at room temperature and different parameters were calculated. DC resistivity measurements for the transition temperature of synthesized superconducting samples were taken by the standard four-probe method, apparatus for which was developed in our laboratory. It is observed that with the substitution of cerium on calcium site the single high-Tc2223 phase is obtained.

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Konkol, Izabela, Jan Cebula, Jolanta Bohdziewicz, Krzysztof Piotrowski, Piotr Sakiewicz, Magdalena Piechaczek-Wereszczyńska e Adam Cenian. "Mineral Deposit Formation in Gas Engines During Combustion of Biogas from Landfills and Municipal WWTP". Ecological Chemistry and Engineering S 27, n. 3 (1 settembre 2020): 347–56. http://dx.doi.org/10.2478/eces-2020-0022.

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AbstractThe biogas produced in municipal wastewater-treatment plants (WWTP) should be cleaned before it can be used as a fuel in internal combustion engines. Efficient running of such engines is possible only subject to using high quality biogas and lubricating oil. Otherwise, biogas impurities in course of complex chemical reactions may form deposits on various engine parts as well as seriously contaminate the lubricating oil. In this paper, mineral deposits containing high concentration of bismuth, silicon, sulphur, calcium and zinc are studied. Silicon deposits demonstrating strong friction properties are formed during combustion of volatile silica compounds. As these deposits build up, abrasion problems, ignition failure and even engine failure result. The bismuth containing deposits comes from bearings degradation, zinc and calcium were derived from the additives present in commercially available lubricating oil, while lead, aluminium, copper, nickel, iron and chromium were introduced by engine wear phenomena. The highest bismuth content was located at the engine cylinder heads and the lowest at the exhaust elements, whereas highest calcium content was registered on the pistons. Silicon containing deposits are highest in the exhaust and lowest at the engine head. Zinc deposits are highest at the piston.

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Tesi sul tema "CALCIUM BISMUTH"

Bouhajib, Abderrahim. "Étude thermodynamique des systèmes bismuth-calcium et calcium-antimoine : calorimétrie, analyse thermique et modélisation numérique des diagrammes de phases". Nancy 1, 1990. http://www.theses.fr/1990NAN10204.

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Les enthalpies de formation des alliages liquides et d'un certain nombre de composés intermétalliques des systèmes binaires (CA,SB) et (BI,CA) ont été mesurées par calorimétrie Calvet. La méthode convient aussi bien pour la formation des alliages liquides que pour la précipitation progressive de composés solides, par ajouts successifs d'un des constituants. Une étude d'analyse thermique différentielle détaillée a été menée pour le système (CA,SB) ; cette étude a révélé l'existence des nouveaux paliers invariants et des phases nouvelles. Les résultats expérimentaux obtenus pour le système (CA,BI) et CA,SB) ont été confrontés aux diagrammes de phases, à l'aide des programmes de calcul d'harmonisation des données expérimentales (programmes LUKAS et NANCYUN). Les difficultés expérimentales d'élaboration ou de contrôle sont liées à l'oxydabilité du calcium ou de certains de ses alliages, ainsi, la plupart des structures ne peuvent être caractérisées qu'en atmosphère neutre ; certaines synthèses demandent un mode opératoire strict. Les intéractions calcium et métal V-B conduisent à des composés solides stabilisés par une basse enthalpie de formation. On retrouve une enthalpie de mélange très négative en phase liquide. L'invariance de l'enthalpie partielle du calcium dans un large domaine de concentration suggère l'existence d'associations fortes à l'état liquide. Enfin, l'enthalpie de formation de CA#1#1SB#1#0 est plus exoénergétique que celle de CA#1#1BI#1#0, ce qui donne une indication sur la stabilité respective de ces deux phases dans les alliages ternaires

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MARTINELLI, ANTONIO E. "Efeito da adicao de chumbo na formacao de fases supercondutoras em ceramicas de Bi-Sr-Ca-Cu-O". reponame:Repositório Institucional do IPEN, 1991. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10260.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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Kim, Seong-Jin. "Directional crystallization in the bismuth-strontium-calcium-copper-oxygen system: Effect of phase separation". Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186040.

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Novel unidirectional crystallization was tested in glasses of the Bi-Sr-Ca-Cu-O system to produce highly oriented microstructures. Some evidence of liquid-liquid phase separations on cooling melts of Bi₂Sr₂Ca₁Cu₂Oₓ and Pb₀ͺ₃₂Bi₁ͺ₆₈Sr₁ͺ₇₅Ca₂Cu₃Oₓ is found for the first time from Differential Thermal Analysis (DTA), X-ray Diffraction (XRD), and Transmission Electron Microscope (TEM). This made it difficult to produce highly oriented microstructures through the present route because one of the phases in the phase separated structure is likely close to "R"-phase composition and lead to copious nucleation of "R"-phase on heating. This also resulted in sequential crystallization of the current liquids, first to "R"-phase and then to the Bi₂Sr₂Ca₁Cu₂Oₓ phase. Theoretical modelling was performed to understand general questions in the present route. The model suggests that a liquid with high interfacial energy is a good candidate for the present route to produce highly oriented microstructures. The model was tested in lithium diborate glass and showed a highly oriented microstructure. Thus, unidirectional crystallization is generally an attractive processing option for a liquid free of phase separation.

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Wan, Xuewen. "Effects of longitudinal disorder on the magnetic field distribution in bismuth strontium calcium copper oxide". W&M ScholarWorks, 2002. https://scholarworks.wm.edu/etd/1539623413.

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Transverse Field muon spin relaxation (TF-muSR) experiments were performed in external magnetic fields 1.0, 2.7, 3.0, 4.5, 5.5, 6.0 and 7.0 T along the Bi2212 crystalline c-axis. For the first time, the heterodyned fitting analysis technique shows that the field profiles on the ab basal planes of single crystal Bi2212 are symmetric in all experimental fields 1.0--7.0 T and at all experimental temperatures 2.0-90.0 K. The muon spin relaxation rates due to the mixed state of Bi2212 were found to increase linearly from 0 mus-1 at the transition temperature, 90.0 K, to about 1.0 mus -1 at the lowest temperature, 2.0 K. The relaxation rates have much less field dependence than the temperature dependence and the field dependence of the relaxation rate is of opposite sign to that seen for YBCO, which is undoubtedly due to vortex lattice disorder caused by the weak coupling between the CuO planes. The scaled magnetic field penetration depths ll0 were found to be independent of magnetic field B in the temperature range 0--50.0 K. Fitting ll0 by currently available models was attempted. A proposed pancake vortex disorder model strongly suggests pancake disordering at all temperatures including 2.0 K, the lowest temperature reached in our experiment. Our experiments and the computer simulation from the pancake vortex disorder model showed that muSR data in this temperature and field range are attributed to the 2-D anisotropic vortex characteristics of Bi2212.

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Kim, Cheol Jin. "Laser float zone growth of superconducting bismuth strontium calcium copper oxide fibers: Characterization and phase equilibria". Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1059411650.

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Bania, William Roger 1964. "Spray pyrolysis processing of yttrium-barium-copper-oxide and bismuth-strontium-calcium-copper-oxide superconducting thin films". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277080.

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The purpose of this investigation was to explore the processing parameters involved in the production of thin film superconductors by spray pyrolysis processing (SPP). The present study is an attempt to optimize the many parameters in SPP. The specific parameters studied were substrate temperature, carrier gas flow rate, substrate materials, solution stoichiometry, spray rate, concentration, starting materials, and substrate to nozzle distance. The effect of these parameters on film stoichiometry and the anticipated superconducting behavior were investigated at some length. Films were routinely produced in a spray chamber designed as a part of this research. Films were analyzed by Rutherford Backscattering Spectroscopy, X-Ray Diffraction, Scanning Electron Microscopy, and Meissner effect measurements.

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Milliken, Damion Alexander. "Uranium doping of silver sheathed bismuth-strontium-calcium-copper-oxide superconducting tapes for increased critical current density through enhanced flux pinning". Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20040810.154223/index.html.

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Bouirden, Lahcen. "Transformations continues et discontinues dans les alliages de plomb microalliés au calcium et au calcium étain pour batteries d'accumulateurs : influence de la vitesse de refroidissement : rôle des impuretés argent, aluminium et bismuth". Nancy 1, 1990. http://www.theses.fr/1990NAN10205.

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Les différents processus de vieillissement des alliages PBCA et PBCASN sont observés par des techniques complémentaires telles que la microcalorimétrie anisotherme, la microscopie optique et électronique, la mesure et l'évolution de la dureté en fonction du temps et de la température. Trois états sont étudiés : produit brut de coulée, produit réhomogénéisé et trempé à l'eau, produit réhomogénéisé et refroidi à l'air. Dans les alliages binaires PBCA, nous trouvons trois transformations discontinues successives dans le temps : une première transformation discontinue à front régulier qui est complète et dont la vitesse est constante. Une seconde transformation discontinue complète ou incomplète dont le front est irrégulier et provoque l'aspect puzzle. Ces deux transformations se font sans précipitation observable. Une troisième transformation discontinue, toujours incomplète, provoque la précipitation discontinue lamellaire de PB#3CA au voisinage des joints de grains. Le rôle des impuretés majeures du plomb secondaire est complexe : AG réduit la vitesse des réactions discontinues, BI l'accélère. AL ajoute comme anti-oxydant, affine la taille des grains et accélère ainsi le vieillissement. Les alliages (PB, CA, SN) sont caractérisés par le rapport atomique R=SN/CA. Pour les faibles valeurs de (R=0,7) les processus de vieillissement sont similaires à ceux des alliages PB, CA. Pour les fortes valeurs de R (R3) une précipitation continue généralisée de CASN#3 se manifeste après une période d'incubation. Pour les valeurs de R intermédiaires, les deux processus apparaissent séparément dans le temps. AG accroît la vitesse de germination et réduit le temps d'incubation, BI et AL aussi, mais moins nettement. Les lois cinétiques des différentes transformations sont établies et les énergies d'activation de la première et de la troisième transformation discontinue

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Antunes, Laurent. "Caractérisation de composites supraconducteurs aléatoires - phases au bismuth/argent : contribution à l'étude des jonctions faibles dans ces matériaux". Phd thesis, Université Sciences et Technologies - Bordeaux I, 1998. http://tel.archives-ouvertes.fr/tel-00163366.

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Les oxydes supraconducteurs à température critique élevée, à base de bismuth et comportant 2 ou 3 plans cuivre, sont synthétisés suivant diverses méthodes. Nous réalisons ensuite l'élaboration par frittage de matériaux composites aléatoires, constitués d'une dispersion de grains supraconducteurs de phase au bismuth 2212 dans une matrice d'argent. Nous étudions la résistivité électrique et l' aimantation en effet d'écran des matériaux en fonction de la température, du champ magnétique et de la concentration en phase supraconductrice. Les comportements observés sont interprêtés dans le cadre d'une approche phénoménologique impliquant la notion de "liens supraconducteurs faibles". Enfin, nous tentons de relier, par des mesures de spectroscopie de photoelectrons X, les informations statistiques obtenues aux caractéristiques chimiques des jonctions intergranulaires.

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Rowan, Fraser S. "A study of the effects of oxygen environment on the stoichiometry, phase assemblage and stability of BiSCCO 2212 and 2201 using EPMA". Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369139.

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A method of performing accurate oxygen analysis on cuprate based superconducting materials was established using electron probe micro analysis (EPMA). A range of YBa₂Cu₃O_δ ceramics with varying oxygen concentration were used to test the method. Using YBCO as a reference material, a suitable standard for oxygen analysis of Bi₂Sr₂CaCu₂O_δ (BiSCCO-2212) materials was obtained. This standard was used to perform full elemental analysis of a range of BiSCCO-2212 crystals, post annealed in pO₂'s between 10^-5-2atm. When the average Cu valence of each crystal was calculated and plotted as a function of the critical temperature (T_c) for each crystal, it was shown that BiSCCO-2212 materials conformed to the 'universal' trend illustrated by most other HTS and did not exhibit anomalous behaviour as had been previously believed. The phase assemblage and superconducting properties of BiSCCO-2212 Ag-clad multifilamental wires, prepared using the powder-in-tube (PIT) method by BICC, were studied as a function of a time/temperature profile. pO₂ of the processing atmosphere was found to be the predominant factor in determining the stoichiometry of the 2212 phase within wires. The phase assemblage is not simply a function of pO₂ as previously believed and can be controlled, in part, by the post annealing temperature. Homogenisation of the phase assemblage in BiSCCO-2212 Ag-clad wires can be achieved by prolonged heating (96hrs) at an appropriate temperature. An investigation into the 10K superconducting BiSCCO phase has shown the Sr-rich solid solution to extend towards the ideal stoichiometry of 2:2:1 (Bi:Sr:Cu) with increasing pO₂. Using a combination of high pO₂ (60atm) to achieve the appropriate Bi:Sr stoichiometry followed by post annealing in N₂ to adjust the oxygen content, it was possible to prepare single-phase ceramics of stoichiometry Bi_2.11(2)Sr_1.90(2)Cu_0.99(2)O_δ with a T_c=10.5K(5).

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Capitoli di libri sul tema "CALCIUM BISMUTH"

Predel, B. "Bi - Ca (Bismuth - Calcium)". In B - Ba … Cu - Zr, 99. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-540-44756-6_59.

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Zazhigalov, Valery O., Olena V. Sachuk, Olena A. Diyuk e Iryna V. Bacherikova. "Mechanochemical and sonochemical syntheses of new nanocomposites". In NEW FUNCTIONAL SUBSTANCES AND MATERIALS FOR CHEMICAL ENGINEERING, 79–92. PH “Akademperiodyka”, 2021. http://dx.doi.org/10.15407/akademperiodyka.444.079.

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For the first time the possibility of the complex nanodispersed compound formation at mechanochemical and sonochemical treatment of the initial compounds mixture was shown. Mechochemical treatment of the mixture of molybdenum oxide and bismuth nitrate permits to obtain of bismuth molybdate in form of nanoparticles, in the same time the treatment of mixture of titanium oxide and calcium hydroxide leads to formation of calcium titanate in form of nanoprisms. It was shown that mechanochemical treatment of the mixture of titanium oxide and tin oxide leads to formation of titanium oxide amorphous layer on tin oxide surface. The mechanism of nanodispersed zinc molybdate formation at sonochemical treatment of initial oxides was established. It was shown that nanocomposites synthesized by these methods demonstrate the higher catalytic activity in organic compounds neutralization processes in water solutions at visible light irradiation and in the process of bioethanol selective oxidation to acetaldehyde and hydrogen in comparison with known analogous catalysts synthesized by traditional methods.

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"Influence of tin , bismuth, calcium, barium, lithium and cobalt". In Magnesium Alloys Containing Rare Earth Metals, 206. CRC Press, 2003. http://dx.doi.org/10.1201/9781482265163-72.

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Pradhan, A. K., P. C. Jana e B. K. Roul. "Bismuth Strontium Calcium Copper Oxide High-Tc Superconductors from Nitrate Solutions". In December 16, 729–33. De Gruyter, 1988. http://dx.doi.org/10.1515/9783112495544-049.

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Pradhan, A. K., P. C. Jana e B. K. Roul. "Bismuth Strontium Calcium Copper Oxide High-Tc Superconductors from Nitrate Solutions". In December 16, 729–32. De Gruyter, 1988. http://dx.doi.org/10.1515/9783112480786-049.

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Sharma, Pramisha, e Ashima Sharma. "Heavy Metals in Ground Water Affect the Human Health Global Challenge". In Advances in Medical Technologies and Clinical Practice, 139–58. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-9831-3.ch007.

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Abstract (sommario):

This chapter is based on a review of heavy metals, high atomic weight, and high-density naturally occurring elements transition elements. In the periodic table, about 80 elements of them are called metals. These metals can be further classified into two categories, those that are essential for survival such as magnesium, potassium, calcium, etc. and those that are nonessential such as lead, mercury, bismuth, and cadmium. These nonessential metals are known as toxic metals. Trace elements such as selenium, zinc, copper, etc. are necessary for maintaining the human body metabolism. These essential elements can be toxic if present at high concentrations. On the other hand, some elements like Hg, Cd, Pb, Bi, Cr, As, etc. are usually toxic to the living organisms when absorbed in small quantities. The source of heavy metals is natural as well as manmade. The toxicity of heavy metals causes carcinogenic effects in human beings related to organ, renal, hepatic, neural, skeletal, and glandular problems.

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Fontani, Marco, Mariagrazia Costa e Mary Virginia Orna. "The Forerunners of Celtium and Hafnium: Ostranium, Norium, Jargonium, Nigrium, Euxenium, Asium, and Oceanium". In The Lost Elements. Oxford University Press, 2014. http://dx.doi.org/10.1093/oso/9780199383344.003.0012.

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Of the naturally occurring nonradioactive elements, hafnium was the next to last to be discovered, preceding the discovery of rhenium by 3 years. It can boast of holding a very strange record: the number of claims for its discovery over the years is unequaled by any other element. This record was the cause of frustration for many scientists who, over the years, took turns in attempts to isolate it. The reason that hafnium remained undiscovered until 1922 lay not so much in that its presence in nature (long known to be quite scarce) wasn’t looked for, but in its peculiar chemical properties that bound it up intimately with zirconium. Toward the end of the 18th century, Martin Heinrich Klaproth melted some forms of yellow-green and red zirconium with sodium hydroxide and then digested the residue several times with hydrochloric and sulfuric acids to eliminate the extraneous silicon. The solution, thought to contain a number of elements, produced, upon addition of potassium carbonate, a generous precipitate. The oxide that Klaproth collected did not seem to belong to any known substance, and he called it terra zirconia. With the passing of the years, he and many other chemists, among them the renowned Jons Jacob Berzelius, determined the elemental composition of zircon and of its correlative minerals. Far from being simply ZrSiO4, zircon contained traces of iron, aluminum, nickel, cobalt, lead, bismuth, manganese, lithium, sodium, zinc, calcium, magnesium, and uranium and small amounts of the rare earths. Some impurities persistently resisted separation from zirconium oxide or zirconia and were taken erroneously for oxides of new elements (new earths). In 1825, Johann Friedrich August Breithaupt (1791–1873) reported the presence of a new element, ostranium, isolated from ostranite, a mineral similar to zircon. Twenty years later, the Swedish chemist, mineralogist, and metallurgist Lars Fredrik Svanberg (1805–78) announced the discovery of a new element. In his publication of 1845, he asserted that the zirconium oxide obtained from a variety of Siberian, Norwegian, and Indian zircon samples was in reality composed of two earths: one, zirconia, already noted, and another unknown earth.

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Atti di convegni sul tema "CALCIUM BISMUTH"

Cheewasukhanont, Wasu, Kitipun Boonin, Pruittipol Limkitjaroenporn e Jakrapong Kaewkhao. "Radiation parameter study of bismuth containing sodium calcium borosilicate glasses". In 2015 4th International Conference on Instrumentation, Communications, Information Technology, and Biomedical Engineering (ICICI-BME). IEEE, 2015. http://dx.doi.org/10.1109/icici-bme.2015.7401371.

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Howell, Richard H., Alison Chaiken, Ronald G. Musket, Mark A. Wall, Mehdi Balooch, D. Phinney, Michael J. Fluss, J. N. Eckstein, Ivan Bozovic e Gary F. Virshup. "Microanalytical study of defect formation in thin bismuth strontium calcium copper oxide films". In OE/LASE '94, a cura di Davor Pavuna e Ivan Bozovic. SPIE, 1994. http://dx.doi.org/10.1117/12.182681.

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Kumar, A. Suneel, T. Narendrudu, S. Suresh, G. Chinna Ram, M. V. Sambasiva Rao, Ch Tirupataiah e D. Krishna Rao. "Characterization and spectroscopic studies of multi-component calcium zinc bismuth phosphate glass ceramics doped with iron ions". In DAE SOLID STATE PHYSICS SYMPOSIUM 2017. Author(s), 2018. http://dx.doi.org/10.1063/1.5028812.

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