TThe present invention relates to a process of production of ammonium niobium oxalate, to the ammonium niobium oxalate produced by said process that presents high purity, monoclinic crystal structure, Nb content in the range from 10 to 30% by weight, which is stable in contact with air at room temperature, and does not show polymerization by aging, is soluble in water, with a solubility in the range from 60 to 160 grams of niobium per liter of water, at temperatures from 20 to 80°C, and to the use of the same as a niobium precursor, suited to the synthesis of functionalized materials such as ceramic, optical lenses, catalysts, high purity niobium oxides, thin films and crystals, in a macrometric to nanometric range, by preparation methods such as sol-gel, precipitation, deposition, impregnation and decomposition, wherein the niobium is the main constituent or is added to the composition as promoter or dopant.

Supported niobium oxides and boria zirconia catalysts are investigated as green catalysts for Fischer indole reaction. By means of wet impregnation, Nb2O5 and B2O3 were loaded onto hydrous zirconia and zirconia as a support. Pore size distribution curves showed that the overlayer was uniformly dispersed onto the mesoporous support. Samples with close to a monolayer coverage had the highest activity in the Fischer indole reaction of phenylhydrazine with 3-heptanone and with cyclohexanone. A coverage higher than a monolayer led to lower activity. From base titration results, both of supported niobium oxides and boria zirconia catalysts are highly acidic. Uncalcined supported niobium oxide exhibited better activity than calcined samples whereas the best calcination temperature for boria zirconia catalaysts was 500B0C. The catalytic activity of used supported niobium oxides can be fully recovered by immersion the solid in H2O2 solution at 40B0C while boria zirconia catalysts were easily regenerated ...

Columbite is the most widespread niobium mineral and makes for an important ore of the industrially useful metal. Niobium, Nb, is used in alloys for improved strength. It also has shown superconductive properties and is being studied with other metals for a possible breakthrough alloy in this new industrial field. Niobium had previously been called columbium hence the name columbite. The official name was made niobium in the 1950s after a century of debate, although some groups still do not recognize the official name and still refer to it as columbite. Of course most geologists still refer to its name sake mineral as columbite instead of the proposed niobite.. Columbite forms a series with the mineral tantalite. In fact the two are often grouped together as a semi-singular mineral called columbite-tantalite in many mineral guides. A series is where two or more elements can occupy the same places within a crystal structure and their respective percentages can then vary. Columbite is the more ...

A coating formulation is described in which includes a solvent, a binder, and a metal additive comprising tantalum, niobium, alloys thereof, or mixtures thereof. Also described is a cellulose-based substrate which contains a cellulose-based reinforcing agent, a binder, and a metal additive comprising tantalum, niobium, alloys thereof, or mixtures thereof. Also described is a cement-based or plaster-based substrate containing a cement-based or plaster-based material and a metal additive comprising tantalum, niobium, alloys thereof, or mixtures thereof.

This article reports on properties of oxide films obtained by anodization of niobium in phosphoric acid before and after the dielectric breakdown. Weak anodic luminescence of barrier oxide films formed during the anodization of niobium is correlated to the existence of morphological defects in the oxide layer. Small sized sparks generated by dielectric breakdown of formed oxide film cause rapid increase of luminescence intensity. The luminescence spectrum of obtained films on niobium under spark discharging is composed of continuum radiation and spectral lines caused by electronic spark discharging transitions in oxygen and hydrogen atoms. Oxide films formed before the breakdown are amorphous, while after the breakdown oxide films are partly crystalline and mainly composed of Nb2O5 hexagonal phase. The photocatalytic activity of obtained oxide films after the breakdown was investigated by monitoring the degradation of methyl orange. Increase of the photocatalytic activity with time is ...related ...

Specifications: Product name: NIOBIUM BORIDE Other name: NIOBIUM BORIDE;COLUMBIUM BORIDE;borylidyneniobium;niobiumboride(nbb);NIOBIUM MONOBORIDE;boranylidyneniobium;COLUMBIUM BORIDE CBB;COLUMBIUM MONOBORIDE CAS number: 12045-19-1 CBNumber:

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Nanoscale defect structure within the magnetic penetration depth of ∼100 nm is key to the performance limitations of niobium superconducting radio frequency cavities. Using a unique combination of advanced thermometry during cavity RF measurements, and TEM structural and compositional characterization of the samples extracted from cavity walls, we discover the existence of nanoscale hydrides in electropolished cavities limited by the high field Q slope, and show the decreased hydride formation in the electropolished cavity after 120 °C baking. Furthermore, we demonstrate that adding 800 °C hydrogen degassing followed by light buffered chemical polishing restores the hydride formation to the pre-120 °C bake level. We also show absence of niobium oxides along the grain boundaries and the modifications of the surface oxide upon 120 °C bake. ...

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books.google.comhttps://books.google.com/books/about/The_chemistry_of_vanadium_niobium_and_ta.html?id=HDEvAQAAIAAJ&utm_source=gb-gplus-shareThe chemistry of vanadium, niobium and tantalum ...

Metallic transition metal dichalcogenides (TMDs)1-8 are good catalysts for the hydrogen evolution reaction (HER). The overpotential and Tafel slope values of metallic phases and edges9 of two-dimensional (2D) TMDs approach those of Pt. However, the overall current density of 2D TMD catalysts remains orders of magnitude lower (~10-100 mA cm−2) than industrial Pt and Ir electrolysers (|1,000 mA cm−2)10,11. Here, we report the synthesis of the metallic 2H phase of niobium disulfide with additional niobium (2H Nb1+xS2, where x is ~0.35)12 as a HER catalyst with current densities of |5,000 mA cm−2 at ~420 mV versus a reversible hydrogen electrode. We find the exchange current density at 0 V for 2H Nb1.35S2 to be ~0.8 mA cm−2, corresponding to a turnover frequency of ~0.2 s−1. We demonstrate an electrolyser based on a 2H Nb1+xS2 cathode that can generate current densities of 1,000 mA cm−2. Our theoretical results reveal that 2H Nb1+xS2 with Nb-terminated surface has free energy for hydrogen

Niobium doped TiO2 thin films were deposited on silica coated glass substrate using aerosol assisted chemical vapour deposition (AACVD) from hexane solution, at 500 °C. The as-deposited films appeared blue, were transparent in the visible, were reflective in the IR region at around 30% and were electrically Celebrating the 2016 RSC Prize and Award Winners Highlighting materials research in the UK for energy and sustainability

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Two dinuclear, oxide- or selenide-bridged, niobium(IV) bis(cyclopentadienyl) tert-butylselenolates have been obtained. These are the first organometallic niobium selenolates to be structurally characterised. In the oxide, the O atom lies on an inversion centre and the Nb-O-Nb linkage is linear, whereas in the selenide (see figure) the Nb-Se-Nb angle is 139.76 Å. This difference can be attributed to π bonding in the oxide.. ...

TABLE-US-00004 TABLE 4 Compositions of Catalysts Catalyst No. First Component Second Component 13 Copper None 1 Manganese None 14 Iron None 15 Niobium None 16 Mixture of Cu, Mn, Fe, Nb None 2 None Cerium 17 None Lanthanum 18 None ML 19 None ML and Cerium 20 Copper Cerium 21 Copper Lanthanum 22 Copper ML 23 Copper ML and Cerium 3 Manganese Cerium 7 Manganese Lanthanum 11 Manganese ML 12 Manganese Neodymium 24 Manganese ML and Cerium 25 Iron Cerium 26 Iron Lanthanum 27 Iron ML 28 Iron ML and Cerium 29 Niobium Cerium 30 Niobium Lanthanum 31 Niobium ML 32 Niobium ML and Cerium 33 Mixture of Cu, Mn, Fe, Nb Cerium 34 Mixture of Cu, Mn, Fe, Nb Lanthanum 35 Mixture of Cu, Mn, Fe, Nb ML 36 Mixture of Cu, Mn, Fe, Nb ML and Cerium 37 Mixture of Cu, Mn ML and Strontium 38 Mixture of Cu, Mn, Fe, Nb ML and Strontium 39 Mixture of Cu, Mn ML, Cerium and Strontium 40 Mixture of Cu, Mn, Fe, Nb ML, Cerium and Strontium 6 Mixture of Cu, Mn ML and Strontium 41 Mixture of Cu, Mn, Fe, Nb ML and Strontium ...

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in spin systems and a Mott insulator-superfluid transition in cold atom systems. I will discuss two recent developments in the theory of quantum phase transitions. Firstly, I will present the fidelity approach to quantum phase transitions, where some equilibrium information about a quantum phase transition is obtained from the overlap between two ground states. This is a simple approach allowing for finding both the critical point separating two phases and the critical exponent of the system describing divergence of the correlation length near the critical point.. Secondly, I will present a simple approach to non-equilibrium quantum phase transitions, i.e., quantum phase transitions happening as a result of finite-rate driving of the system from one phase to another. Such driving results in creation of topological defects during the symmetry-breaking transitions (vortices, kinks, etc.). The theory that I will ...

Journal of Metallurgy is a peer-reviewed, Open Access journal that publishes original research articles as well as review articles in all areas of metallurgy.

Organoniobium chemistry is the chemistry of compounds containing niobium-carbon (Nb-C) bonds. Organoniobium compounds often have niobium in the oxidation state +5. A convenient starting material is niobium(V) chloride. Organoniobium(V) compounds are often strongly oxophilic. Organoniobium and organotantalum chemistry are similar, except that the tantalum compounds are more resistant to reduction. Niobocene dichloride ((C5H5)2NbCl2), a metallocene, is a derivative of Nb(IV). It oxidizes in air to give the oxychloride Cp2NbOCl, a Nb(V) derivative, and correspondingly diamagnetic. Derivatives of pentamethylcyclopentadiene are also known, such as (C5Me5)2NbH3. The anion [Nb(CO)6]− is the simplest carbonyl of niobium. It is obtained by reduction of NbCl5 under an atmosphere of CO using sodium-potassium alloy. C. R. Lucas (1990). Dichlorobis(η5-Cyclopentadienyl)Niobium(IV). Inorg. Synth. 28: 267-270. doi:10.1002/9780470132593.ch68. ISBN 0-471-52619-3. J. E. Ellis, A. Davison, (1976). ...

Page contains details about vertically aligned niobium nanowire array . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com

The Jacobsen and pybox type ligands effect chiral induction in the presence of niobium(V) chloride and tantalum(V) chloride in the Lewis acid catalysed Diels-Alder reaction.

This market research report examines the foreign trade of Japan and its perspectives on the global market for niobium tantalum vanadium zirconium ores,

Produk tantalum dan niobium produk yang logam langka menampilkan titik leleh tinggi dan titik perbautan tinggi. Mereka juga mencirikan ketahanan korosi, superkonduktivitas dan konduktivitas listrik monopolar.

A mehod for separating 95Zr from 15Nb by extraction process with din-n-octyl-methylene-bis-phosphonic acid (DOMPA), of the for mula CH2[PO(OCsH11)0Hh, is given. Extraction behav iour of both metals under different conditions has been...

An iron-based high-silicon alloy contains (in weight percent) 2.6-3.5% carbon, 3.7-4.9% silicon, 0.45-1.0% niobium, up to 0.6% manganese, up to 0.02% sulfur, up to 0.02% phosphorus, up to 0.5% nickel,

Hypo allergenic earwires and jewellery findings made from colourful anodized niobium and titanium. Available by mail order in the UK, low postage and packing rates.

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Niobium (Nb) Lumina Hollow Cathode Lamp, Diameter: 50mm (2in.) designed to be used with PerkinElmers AAnalyst™ series of instruments.

Listings in Nanopositioning Systems, Cryocoolers, Molybdenum, Evaporation Sources, Computer-Aided Design / Engineering, Niobium, Titanium and Chemical...

That brings us to Niobium-Resonator. Well, a resonator is a device for storing electromagnetic radiation, and niobium is a rare metal commonly used in building such devices. Resonator are vital component parts of the photoinjectors. As far as particle physicists are concerned, it might as well be gold. I found some statistics on how important this substance is for the future International Linear Collider (ILC). It will use over 500 tons of pure niobium to build 20,000 superconducting radio-frequency (rf) cavities, devices that accelerate electrons and their antimatter twins, positrons, along microwaves to near-light speeds. That means metal-refining factories would have to work at full capacity for three to four years solely to create highly-refined niobium for the ILC. Currently at three hundred dollars a pound, the niobium alone would cost the ILC upwards of three hundred million dollars. It will collide electrons with positrons. It will be between 30 km and 40 km long, more than 10 times as ...

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TY - JOUR. T1 - LiNbO3 coating on concrete surface. T2 - A new and environmentally friendly route for artificial photosynthesis. AU - Nath, Ranjit K.. AU - Mohd. Zain, Muhammad Fauzi. AU - Kadhum, Abdul Amir H.. PY - 2013. Y1 - 2013. N2 - The addition of a photocatalyst to ordinary building materials such as concrete creates environmentally friendly materials by which air pollution or pollution of the surface can be diminished. The use of LiNbO3 photocatalyst in concrete material would be more beneficial since it can produce artificial photosynthesis in concrete. In these research photoassisted solid-gas phases reduction of carbon dioxide (artificial photosynthesis) was performed using a photocatalyst, LiNbO3, coated on concrete surface under illumination of UV-visible or sunlight and showed that LiNbO3 achieved high conversion of CO2 into products despite the low levels of band-gap light available. The high reaction efficiency of LiNbO3 is explained by its strong remnant polarization (70 ...

Tantalum and other group VB transition metal carbides comprise of a class of ultra-high temperature ceramics (UHTCs) that are of particular use in machining tools and fuel-cladding on nuclear reactors. These material microstructures are controlled by the co-precipitation of metal-rich carbide phases, which in turn vary the mechanical properties based on the phase content. The major consideration in the use of UHTCs is their inherent brittleness, and currently little is known about their mechanical behavior in regards to varying microstructures and phase content, especially in niobium carbides. This thesis explores the flexural and fracture properties of two types of group VB transition metal UHTCs: tantalum carbide of carbon/tantalum (C/Ta) ratio in 0.5, 0.75 and 1.0, and niobium carbide of carbon/niobium (C/Nb) composition of 0.5, 0.67, 0.75 and 1.0. It is hypothesized that because of the carbon ratio, a second acicular shape phase will precipitate and ultimately increase the fracture toughness ...

Our product range features a comprehensive spectrum of tantalum and niobium compounds adapted for a wide variety of applications and markets. Our tantalum and niobium oxalate solutions are completely soluble compounds that can be used for mixtures at atomic level. These mixtures are applied for example in the production of catalytic converters and electroceramics. One example of oxalates is our niobium ammonium oxalate. In multilayered ceramic capacitors (MLCCs) NAmOx is used to increase capacity. Doping the carrier material barium titanate with NAmOx positively affects the capacitys dependence on temperature. This supports the trend toward miniaturization of electrical end devices by allowing optimum use of existing space. NAmOx is also used as a dopant in the battery industry to increase the conductivity of cathode materials. Doping with NAmOx can also achieve increases in battery charge/discharge cycles ...

Other articles where Heinrich Rose is discussed: niobium: In 1844 a German chemist, Heinrich Rose, discovered what he considered to be a new element occurring along with tantalum and named it niobium after Niobe, the mythological goddess who was the daughter of Tantalus. After considerable controversy it was decided that columbium and niobium were the same element. Eventually…

A Japanese company, Showa Denko, has developed a catalyst meant for polymer electrolyte fuel cells that use niobium and titanium as the main components, with the addition of carbon and nitrogen. A catalyst made from the new blend could replace platinum catalysts in the fuel cells. These new catalysts also have the advantage of not oxidizing, as platinum does in the air electrode. And, of course, both niobium and titanium are less expensive than platinum.. Everything isnt set, however. Catalysts based on niobium or titanium have not shown the same level of performance in fuel cells as platinum. Nikkei Electronics Asia reports on the performance issues faced by Showa Denko:. Platinum performance is still four or five times higher, says a source at Showa Denko. The firm joined the NEDO project in July 2008, and says there is still considerable room for improvement. For example, the catalyst particles are large at about 40nm, but they expect performance to rise with smaller particle sizes. Even ...

Deviations in Q for resonant superconducting radio frequency niobium accelerator cavities are generally correlated with resistivity loss mechanisms. Field dependent Qs are not well modeled by these classical loss mechanisms, but rather can represent a form of precision cavity surface thermometry. When the field dependent Q variation shows improvement with increasing B field level the classical treatment of this problem is inadequate. To justify this behavior hydrogen as a ubiquitous impurity in niobium, which creates measurable property changes, even at very low concentrations is typically considered the cause of such anomalous behavior. This maybe the case in some instances, but more importantly any system operating with a highly coherent field with a significant time dependent magnetic component at near 2° K will have the ability to organize the remaining free spins within the London penetration depth to form a coupled energy reservoir in the form of low mass spin waves. The niobium resonant ...

Piezoelectric materials are utilized for high-power ultrasonic devices such as ultrasonic motors, which are driven under high stress and strain. The nonlinear elastic vibration of piezoelectric materials is a critical problem because it degrades the output performance. (Bi,Na)TiO3-BaTiO3 (BNBT) ceramics are one of the lead-free piezoelectric materials that show outstanding characteristics under high power driving, such as stable mechanical quality factor and resonance frequency. We evaluated the high-power characteristics of BNBT ceramics by measuring complex higher-order elastic constants using a nonlinear piezoelectric vibration model. We found that the absolute value of the higher-order elastic constant of BNBT was less than 4% of Pb(Zr,Ti)O3 (PZT). Additionally, we developed a miniature ultrasonic motor using a BNBT multilayered piezoelectric transducer. This multilayered structure was utilized to enhance the piezoelectric displacement and was equipped with elastic fins, which convert the ...

Energy harvesting using piezoelectric material has been one of the hottest interests in powering wireless sensor nodes without maintenance and replacement of wired or battery power system in ubiquitous era. Unlike most of the previous research and applications which have focused on cantilever type of piezoelectric energy converting methods, this research tests 33 mode piezo material which converts relatively vibration of unfixed frequency from ambient vibration into electric energy. To transmit the impact loading to piezo material, we conducted the ball drop experiment. Based on the theoretical model to predict the total stress and voltage influenced by such factors as size of piezo material and mass and velocity of impact material (ball), tests are conducted to earn the optimal estimates of size of PZT and mass and velocity of impact materials for desired energy harvestings concerning its various applications. By altering mass and velocity of impact materials, it is observed to vary voltage

High-purity tantalum and niobium oxides enhance the refractive index of specialty lenses for high-end cameras or cameras in parking assistance systems. Through doping, they also increase the performance of multi-layered ceramic capacitors (MLCCs). Lithium niobate and lithium tantalate derived from high-purity oxides, are used to manufacture electronic components like surface acoustic wave (SAW) filters which can be applied in mobile devices.. As one of the leading suppliers of high-purity tantalum and niobium oxides, we are a reliable partner for customers throughout all industries. With our experience and expertise in application technology, we can provide product solutions with customised morphology, purity and recycling services to match your requirements. ...

This white paper from AVX considers the low-leakage current aspect of designing with tantalum and niobium-oxide capacitors. Leakage current (DCL) is a common effect of all capacitors and its value and dependencies on electrical and environmental conditions are related to capacitor technology. According to this paper, which presents graphs and equations in support of its conclusions, AVXs TRJ, TAJ and NOJ tantalum and niobium-oxide capacitors are most suitable to support the battery in handheld and TPMS transmitter applications.. ...

Abstract: Topological quantum phase transitions can be reflected by the sudden jump of certain physical response functions. Typical examples include the plateau transition in the integer quantum Hall systems accompanied by the jump of Hall conductance and the transition between quantum spin Hall state and normal insulator state featured by the jump of the two-terminal conductance. In this work, we demonstrate that the piezoelectric response can also change discontinuously across a topological quantum phase transition in two-dimensional time-reversal invariant systems with spin-orbit coupling. We study all gap closing cases for all 7 plane groups that allow non-vanishing piezoelectric tensor and find that any gap closing with 1 fine-tuning parameter between two gapped states changes either the $Z_2$ invariant (characterizing the quantum spin Hall phase) or the locally stable valley Chern number (characterizing the valley Hall phase). The jump of the piezoelectric response is found to exist for ...

inproceedings{BUT9080, author=Josef {Šikula} and Jan {Hlávka} and Vlasta {Sedláková} and Lubomír {Grmela} and Pavel {Höschel} and Tomáš {Zedníček}, title=Conductivity mechanisms, breakdown and noise characteristics of niobium oxide capacitors, annote=Niobium Oxide capacitor, known as OxiCap, has already found its place in the market as a cheap and reliable non-burning component. The study of conductivity mechanisms has been done to prove its excellent stability, reliability and non-burning performance. Set of electrical measurements as VA characteristics in forward and reverse mode, frequency characteristics of capacitance, temperature or time dependency of basic parameters together with measurements of basic physical parameters enabled to propose the theoretical model of NbO - Nb2O5 - MnO2 system. OxiCap shows identical conductivity mechanism as tantalum capacitor, but furthermore a unique mechanism appears after dielectric breakdown. It causes a high resistance failure mode of ...

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Practical infrared single photon detector systems. Gemmell, N. R. et al. (2017) Miniaturized 4 K platform for infrared superconducting photon counting detectors Supercodnuctor Science and Technology 30, 11LT01 (doi:10.1088/1361-6668/aa8ac7). Natarajan, C. M. et al. (2012) Superconducting nanowire single-photon detectors: physics and applications Superconductor Science and Technology, 25 (6). 063001. ISSN 0953-2048 (doi:10.1088/0953-2048/25/6/063001). Distributed fibre temperature sensing. Tanner, M.G et al. (2011) High-resolution single-mode fiber-optic distributed Raman sensor for absolute temperature measurement using superconducting nanowire single-photon detectors Applied Physics Letters, 99 (20). p. 201110. ISSN 0003-6951 (doi:10.1063/1.3656702). Singlet oxygen luminescence detection. Gemmell, N. R., McCarthy, A., Kim, M. M., Veilleux, I., Zhu, T. C., Buller, G. S., Wilson, B. C., and Hadfield, R. H. (2016) A compact fiber-optic probe-based singlet oxygen luminescence detection ...

The lecture course provides an introduction to field theoretic methods for systems with many degrees of freedom. A focus will be set on quantum phase transitions, with special emphasis on applications to ultracold, mostly bosonic, atomic gases as they are the subject of many fore-front present-day experiments. The course will introduce to the basis of the theory of classical and quantum phase transitions, with a special emphasis on simple model applications. Methodologically, the lecture will build on the basics of the operator as well as the path-integral approach to quantum field theory. Knowledge of the basics of quantum mechanics, statistical mechanics, and quantum field theory is presumed ...

We discovered several new energetically competitive structures of NbSe2 using the multi-algorithm collaborative (MAC) crystal structure prediction algorithm combined with the density functional theory. It was found that the coordination number of Nb in NbSe2 is increased from 6 to 7, and then to 8 with incre