ChemInform Abstract: Catalytic Low-Temperature Oxydehydrogenation of Methane to Higher Hydrocarbons with Very High Selectivity at 8-12% Conversion

ChemInform ◽  
2010 ◽  
Vol 23 (34) ◽  
pp. no-no
Author(s):  
J. RASKO ◽  
G. A. SOMORJAI ◽  
H. HEINEMANN
Keyword(s):  
Low Temperature ◽  
High Selectivity ◽  
Higher Hydrocarbons ◽  
Very High

Molecule-Based Magnets—An Overview

MRS Bulletin ◽  
2000 ◽  
Vol 25 (11) ◽  
pp. 21-30 ◽  
Author(s):  
Joel S. Miller ◽  
Arthur J. Epstein
Keyword(s):  
Low Temperature ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Magnetic Ordering ◽  
Low Density ◽  
Materials Properties ◽  
The Common ◽  
New Processing ◽  
Very High

Molecule-based magnets are a broad, emerging class of magnetic materials that expand the materials properties typically associated with magnets to include low density, transparency, electrical insulation, and low-temperature fabrication, as well as combine magnetic ordering with other properties such as photoresponsiveness. Essentially all of the common magnetic phenomena associated with conventional transition-metal and rare-earth-based magnets can be found in molecule-based magnets. Although discovered less than two decades ago, magnets with ordering temperatures exceeding room temperature, very high (∼27.0 kOe or 2.16 MA/m) and very low (several Oe or less) coercivities, and substantial remanent and saturation magnetizations have been achieved. In addition, exotic phenomena including photoresponsiveness have been reported. The advent of molecule-based magnets offers new processing opportunities. For example, thin-film magnets can be prepared by means of low-temperature chemical vapor deposition and electrodeposition methods.

Angular dependence ofJcfor YBCO coated conductors at low temperature and very high magnetic fields

2009 ◽  
Vol 23 (1) ◽  
pp. 014003 ◽  
Author(s):  
A Xu ◽  
J J Jaroszynski ◽  
F Kametani ◽  
Z Chen ◽  
D C Larbalestier ◽  
...  
Keyword(s):  
Low Temperature ◽  
Magnetic Fields ◽  
Angular Dependence ◽  
Coated Conductors ◽  
High Magnetic Fields ◽  
Ybco Coated Conductors ◽  
Very High

scholarly journals Gold in Irish Coal: Palaeo-Concentration from Metalliferous Groundwaters

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 635
Author(s):  
Liam A. Bullock ◽  
John Parnell ◽  
Joseph G.T. Armstrong ◽  
Magali Perez ◽  
Sam Spinks
Keyword(s):  
Heat Flow ◽  
Low Temperature ◽  
Precious Metals ◽  
High Heat ◽  
Selenium Content ◽  
Foreland Basins ◽  
High Heat Flow ◽  
South Wales ◽  
First Time ◽  
Very High

Gold grains, up to 40 μm in size and containing variable percentages of admixed platinum, have been identified in coals from the Leinster Coalfield, Castlecomer, SE Ireland, for the first time. Gold mineralisation occurs in sideritic nodules in coals and in association with pyrite and anomalous selenium content. Mineralisation here may have reflected very high heat flow in foreland basins north of the emerging Variscan orogenic front, responsible for gold occurrence in the South Wales Coalfield. At Castlecomer, gold (–platinum) is attributed to precipitation with replacive pyrite and selenium from groundwaters at redox interfaces, such as siderite nodules. Pyrite in the cores of the nodules indicates fluid ingress. The underlying Caledonian basement bedrock is mineralised by gold, and thus likely provided a source for gold. The combination of the gold occurrences in coal in Castlecomer and in South Wales, proximal to the Variscan orogenic front, suggests that these coals along the front could comprise an exploration target for low-temperature concentrations of precious metals.

scholarly journals Pd/FER vs Pd/SSZ-13 Passive NOx Adsorbers: Adsorbate-controlled Location of Atomically Dispersed Pd(II) in FER Determines High Activity and Stability

2020 ◽  
Author(s):  
Konstantin Khivantsev ◽  
Xinyi Wei ◽  
Libor Kovarik ◽  
Nicholas R. Jaegers ◽  
Eric D. Walter ◽  
...  
Keyword(s):  
Low Temperature ◽  
Beneficial Effect ◽  
Hot Spots ◽  
Release Behavior ◽  
Hydrothermal Aging ◽  
Practical Applications ◽  
Systematic Exploration ◽  
No Release ◽  
Co Concentration ◽  
Very High

<p>Pd-loaded FER and SSZ-13 zeolites as low-temperature passive NOx adsorbers (PNA) are compared under practically relevant conditions. Vehicle cold-start exposes the material to CO under a range of concentrations, necessitating a systematic exploration of the effect of CO on the performance of isolated Pd ions for PNA. NO release temperature of both adsorbers decreases gradually with the increase of CO concentration from a few hundred to a few thousand ppm. This beneficial effect results from local nano-“hot spots” formation during CO oxidation. Dissimilar to Pd/SSZ-13, increasing the CO concentration above ~1,000 ppm improves the NOx storage significantly for Pd/FER, attributed to the presence of a Pd ions in FER γ-site that is shielded from NO<sub>x</sub>. CO mobilizes this Pd atom to the NO<sub>x</sub> accessible position where it becomes active for PNA. This behavior explains the very high resistance of Pd/FER to hydrothermal aging: Pd/FER materials survive hydrothermal aging at 800⁰C in 10% H<sub>2</sub>O vapor for 16 hours with no deterioration in NOx uptake/release behavior. Thus, by allocating Pd ions to the specific microporous pockets in FER, we have produced very hydrothermally stable and active PNA materials with immediate practical applications.<br></p>

scholarly journals Aluminum oxide carrier for a catalyst for low-temperature isomerization of hydrocarbons

2020 ◽  
Vol 15 (3) ◽  
pp. 58-69
Author(s):  
N. Tagandurdyyeva ◽  
N. V. Maltseva ◽  
T. A. Vishnevskaya ◽  
V. N. Narayev ◽  
A. Yu. Postnov
Keyword(s):  
Low Temperature ◽  
Polyvinyl Alcohol ◽  
Aluminum Oxide ◽  
High Selectivity ◽  
Ph Value ◽  
Strength Properties ◽  
Isomerization Reaction ◽  
Preparation Conditions ◽  
Constant Ph ◽  
Extrusion Method

Objectives. Determine the necessary conditions for obtaining a granulated η-Al2O3 carrier, investigate its structural and strength properties, and evaluate its activity for the model n-butane isomerization reaction.Methods. Samples containing bayerite structure aluminum trihydroxide were synthesized by precipitation from aqueous solutions of aluminum nitrate with ammonia under isothermal conditions at a constant pH value. The samples of the granulated carrier were obtained using an extrusion method when the composition of molding pastes was varied by tuning the ratio of bayerite- and η-Al2O3 -containing components and introducing polyvinyl alcohol.Results. The influence of the preparation conditions on the structural and strength properties of the active Al2O3 granules is evaluated. Samples of the aluminum oxide carrier were tested for a model reaction of low-temperature isomerization of n-butane, demonstrating a sufficiently high selectivity and reasonable prospects for use as catalysts for low-temperature isomerization of hydrocarbons.Conclusions. Increasing the content of the polyvinyl alcohol in the molding paste from 0.4 to 1.8 wt % is accompanied by an increase in the predominant sizes of the mesopores in the range of 10–50 nm and pores in the range of 50–80 nm, explaining the high values of all recorded parameters for the process of isomerization of n-butane.

Synthesis of CuxNi(1−x)O coral-like nanostructures and their application in the design of a reusable toxic heavy metal ion sensor based on an adsorption-mediated electrochemical technique

2017 ◽  
Vol 4 (1) ◽  
pp. 191-202 ◽  
Author(s):  
Sayan Dey ◽  
Sumita Santra ◽  
Anupam Midya ◽  
Prasanta Kumar Guha ◽  
Samit Kumar Ray
Keyword(s):  
Heavy Metal ◽  
Detection Limit ◽  
Metal Ion ◽  
High Selectivity ◽  
Heavy Metal Ion ◽  
Electrochemical Technique ◽  
Toxic Heavy Metal ◽  
Ion Sensors ◽  
Metal Ion Sensors ◽  
Very High

Nanostructured, Cu-doped nickel oxides serve as excellent, ultra-fast, re-usable heavy metal ion sensors with an ultra-low detection limit and very high selectivity towards toxic Cr(vi) ions.

A Novel Latching Relay Fabricated Using an Oxide Molded Tungsten Process

2005 ◽  
Vol 872 ◽  
Author(s):  
J.G. Fleming ◽  
Michael Baker ◽  
David Luck
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Tensile Stress ◽  
Vapor Deposition ◽  
Chemical Mechanical Polishing ◽  
Chemical Vapor ◽  
Metal Contacts ◽  
Cmos Compatible ◽  
Mems Device ◽  
Very High

AbstractIn this paper we describe an oxide molded tungsten process applied to the fabrication of a novel latching relay. The steps in the process are: deposition of a sacrificial oxide, patterning of the oxide, filling of the resulting mold with a blanket film of tungsten using chemical vapor deposition (CVD), and then the removal and planarization of excess tungsten through chemical mechanical polishing (CMP). The process for the incorporation of dielectric isolation has also been developed. The resulting tungsten structures are under high tensile stress, which appears to be compensated in process by the compressive stress of the oxide mold. All the steps are low temperature and the entire process is backend CMOS compatible. This process has been used to fabricate a latching relay which relies on the internal stress of the tungsten and always generates force in a pulling mode. Parts have been successfully fabricated and tested, the devices generate very high forces for a MEMS device and give reasonable contact resistances even without noble metal contacts.

Hydrogen-atom tunneling through a very high barrier; spontaneous thiol → thione conversion in thiourea isolated in low-temperature Ar, Ne, H2and D2matrices

2018 ◽  
Vol 20 (20) ◽  
pp. 13994-14002 ◽  
Author(s):  
Hanna Rostkowska ◽  
Leszek Lapinski ◽  
Maciej J. Nowak
Keyword(s):  
Hydrogen Atom ◽  
Low Temperature ◽  
Chemical Bond ◽  
Very High

Hydrogen-atom tunneling in thiourea involves breaking of the S–H chemical bond and the formation of a new N–H bond.

Fermi–Dirac Statistics

2019 ◽  
pp. 386-403
Author(s):  
Robert H. Swendsen
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Specific Heat ◽  
Fermi Energy ◽  
Fermi Gas ◽  
Main Application ◽  
Densities Of States ◽  
Low Temperature Specific Heat ◽  
Very High ◽  
The Ideal

The main application of Fermi–Dirac Statistics is to calculate the properties of electrons. This chapter explains how the properties of fermions account for the behavior of metals. The Fermi energy is introduced and shown to correspond to a very high temperature, so that most properties can be obtained from low-temperature expansions. Both discrete and continuous densities of states are discussed. The Sommerfeld expansion is derived explicitly. The low-temperature specific heat and compressibility are derived. The most important fermions are electrons, and understanding the properties of electrons is central to understanding the properties of all materials. In this chapter we will study the ideal Fermi gas, which turns out to explain many of the properties of electrons in metals.

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