REACTIVE ACCELERATED CLUSTER EROSION (RACE)

1996 ◽  
Vol 03 (01) ◽  
pp. 897-900 ◽  
Author(s):  
JÜRGEN GSPANN
Keyword(s):  
Kinetic Energy ◽  
Chemical Reactions ◽  
Target Material ◽  
Surface Erosion ◽  
Reaction Products ◽  
Surface Structuring

Beams of ionized clusters of some thousand atoms are accelerated to about 100-keV kinetic energy to be used for area selective surface erosion. Mask projective cluster-impact lithography allows surface structuring in the submicron regime. Chemical reactions between the cluster and the target material may provide volatile reaction products facilitating ejecta removal. The reactive accelerated cluster erosion (RACE) process is applied to metals like copper and gold, to semiconductors such as silicon, and to insulators like glass, quartz, or sapphire, giving very smooth eroded surface and steep sidewalls.

Chemically Selective Reactions in Confined Spaces in Hybrid Aerogels

2005 ◽  
Vol 899 ◽  
Author(s):  
Xipeng Liu ◽  
Chunhua Yao ◽  
William M Risen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Metal Ions ◽  
Chemical Reactions ◽  
Reaction Products ◽  
Spatial Confinement ◽  
Confined Spaces ◽  
Hybrid Silica ◽  
Hybrid Aerogels ◽  
Chemically Selective

AbstractBy employing novel hybrid silica/functional polymer aerogels, control of the course of chemical reactions between reactants confined inside of the aerogels with reactants whose access to the confinement domain is controlled by diffusion has been explored. Thus, monolithic silica/biopolymer hybrid aerogels have been synthesized with coordinated metal ions that can react with amino acids, such as L-cysteine, that are provided externally in a surrounding solution. Metal ions, such as Au(III), that can react in solution with the amino acid to produce one set of products under a given set of stoichiometric or concentration conditions, and a different set of products under a second set of conditions, were selected for incorporation into the aerogel. It was discovered that the course of the reaction can be changed by spatial confinement of the reaction domain in the aerogel. For example, in the case of Au(III) and L-cysteine, the Au(III) ions are confined in nanoscale domains, and when they are reacted with the amino acid, the nature of the reaction products is controlled by diffusion of the L-cysteine into the domains. Exploration of these and related phenomena will be presented.

THE PRODUCTION OF 13N2 BY 50-MeV PROTONS FOR USE IN BIOLOGICAL NITROGEN FIXATION

1967 ◽  
Vol 13 (5) ◽  
pp. 587-599 ◽  
Author(s):  
N. E. R. Campbell ◽  
Ram Dular ◽  
H. Lees ◽  
K. G. Standing
Keyword(s):  
Nitrogen Fixation ◽  
Azotobacter Vinelandii ◽  
Continuous Production ◽  
Target Material ◽  
Experimental System ◽  
Beam Current ◽  
Reaction Products ◽  
Arctic Soils ◽  
Number Of Microorganisms ◽  
Biological Nitrogen

An experimental system for the continuous production of radioisotopic nitrogen, 13N2, has been developed using the sector-focused cyclotron at the University of Manitoba. The radioisotope is produced by 50 MeV proton bombardment of 14N2 with powdered melamine as the nitrogen-containing target material. A trap system necessary for the removal of unwanted reaction products is described and details of experimental procedures involving changes in proton beam current and in state of beam focus are presented.Using the radioisotope, a number of microorganisms isolated from sub-Arctic soils of the Fort Churchill region have been examined for their nitrogen fixation potential. Several of these, including a species of Rhodotorula and a species of Pullularia in addition to bacterial forms, have demonstrated nitrogen fixation at a rate comparable with that shown by Azotobacter vinelandii.

scholarly journals Optical Radiation from the Sputtered Species under Excitation of Ternary Mixtures of Noble Gases by the 6Li(n,α)3H Nuclear Reaction Products

2021 ◽  
Vol 23 (2) ◽  
pp. 95
Author(s):  
K. Samarkhanov ◽  
M. Khasenov ◽  
E. Batyrbekov ◽  
Yu. Gordienko ◽  
Yu. Baklanova ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Nuclear Reaction ◽  
Alkali Metals ◽  
Nuclear Reactor ◽  
Noble Gases ◽  
Noble Gas ◽  
Alpha Particles ◽  
Ternary Mixtures ◽  
Reaction Products ◽  
Energy Excitation

The present paper examines the luminescence of ternary Ar-Kr-Xe and Ne-Ar-Kr mixtures of noble gases in the spectral range from 300 to 970 nm, excited by the 6Li(n,α)3H nuclear reaction products in the core of a nuclear reactor. A thin layer of lithium applied on the walls of the experimental device, stabilized in the matrix of the capillary-porous structure, serves as a source of gas excitation. During in-pile tests, conducted at the IVG.1M research reactor, thermal neutrons interact via the 6Li(n,α)3H reaction, and the emergent alpha particles with a kinetic energy of 2.05 MeV and tritium ions with a kinetic energy of 2.73 MeV excite gaseous medium. The study was carried out in a wide temperature range. The temperature dependence of the intensity of the emission of the atoms of noble gases and alkali metals, heteronuclear ionic molecules of noble gases were studied. The obtained values of the activation energy of the emission process 1.58 eV for lithium and 0.72 eV for potassium agree well with the known values of evaporation energy. Excitation of alkali metals atoms occurs consequently of the Penning process of alkali metals atoms on noble gas atoms in the 1s-states and further ion-molecular reactions.

scholarly journals Dynamics of Molecular Processes and the Sustainable Development of Humanity

2017 ◽  
Vol 01 (01) ◽  
pp. 66-73
Author(s):  
Yuan Tseh Lee
Keyword(s):  
Sustainable Development ◽  
Global Warming ◽  
Chemical Reactions ◽  
Carbon Emissions ◽  
Molecular Beams ◽  
Reaction Products ◽  
Molecular Processes ◽  
The Sustainable Development ◽  
Single Collision ◽  
Elementary Chemical

Yuan Tseh Lee was instrumental in the development and construction of an apparatus that utilized crossed molecular beams, presenting a break-through technique that allowed for the understanding of the dynamics of elementary chemical reactions. This was done by following the trajectories of reactants and reaction products in single collision events, allowing the visualization of the dynamics of how chemical reactions take place. This article also highlights Prof. Lee’s belief in the severity of the consequences of global warming and his concerns relating to the need to substantially reduce carbon emissions.

scholarly journals Simulated Sunlight Selectively Modifies Maillard Reaction Products in a Wide Array of Chemical Reactions

2019 ◽  
Vol 25 (57) ◽  
pp. 13208-13217 ◽  
Author(s):  
Daniel Hemmler ◽  
Michael Gonsior ◽  
Leanne C. Powers ◽  
James W. Marshall ◽  
Michael Rychlik ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Maillard Reaction ◽  
Maillard Reaction Products ◽  
Simulated Sunlight ◽  
Reaction Products

Mixture of the Reaction Products during Hardening of the Water Glass Radiation-Protective Composites

2013 ◽  
Vol 746 ◽  
pp. 289-292 ◽  
Author(s):  
Evgeniy Valerjevich Korolev ◽  
Anna Nikolaevna Grishina
Keyword(s):  
Chemical Composition ◽  
Phase Analysis ◽  
Chemical Reactions ◽  
Water Glass ◽  
Building Materials ◽  
Water Resistance ◽  
Barium Chloride ◽  
Reaction Products ◽  
X Ray

The water glass can be used as a binder for the design of water-resistant radiation-protective building materials. In the present work the possibility of hardening of such materials by barium chloride is investigated. The chemical reactions which can take place during the structure forming and lead to the formation of barium hydrosilicates are presented. It is shown by means of X-ray phase analysis that formation of such hydrosilicates of composition BaO·SiO2·6Н2О, BaO·2SiO2·4Н2О, Ba2[SiO2(OH)2]2and BaO·SiO2·Н2О actually occurs. The influence of the quantity of hardener to the chemical composition of the reaction products is examined. The effect of the reaction products to the water resistance of composite is studied. It is shown that water resistance can be increased in case of stochiometric quantity of barium chloride; in such case the primary product of reaction is BaO·2SiO2·4Н2О.

scholarly journals Chemical reactions during iron reduction from oxides

2020 ◽  
Vol 63 (10) ◽  
pp. 842-847
Author(s):  
V. I. Berdnikov ◽  
Yu. A. Gudim
Keyword(s):  
Carbon Monoxide ◽  
Chemical Reactions ◽  
Iron Reduction ◽  
Direct Method ◽  
Direct Reduction ◽  
Iron Carbide ◽  
Reducing Agents ◽  
Reaction Products ◽  
Program Complex ◽  
Subsequent Conversion

The chemical process, accompanied by iron reduction from hematite, was modeled by computer program complex TERRA (product of MGTU im. N.E. Bauman). Carbon, hydrogen and methane were used as reducing agents. By varying the costs of reducing agents and process temperatures, equilibrium concentrations of the system components were determined. Change in these concentrations at the boundaries of individual temperature regions was regarded as a result of the passage of appropriate chemical reactions in them. At the same time, it was noted that the nonvariant type reactions begin and end at the same fixed temperatures. Calculations have shown that the conversion of Fe2O3 → Fe3O4 in all cases was thermodynamically possible at temperatures exceeding 65 °C. Therefore, at operating temperatures of the furnace it will be implemented without complications. The second stage of reduction also took place under a single scheme Fe3O4 → Fe, bypassing the participation of FeO oxide. The temperatures of beginning of iron reduction by components C, H2 and CH4 were respectively 680, 350 and 520 °C. In this case, there was only a direct reduction of iron by these components. An attempt to fix the fact of indirect reduction, using carbon monoxide as a reducing agent, was unsuccessful even with a large consumption of it. Carbon monoxide decomposed at low temperatures by the Bell-Boudoir reaction. Therefore, later iron was restored by means of “soot” carbon and that is also a direct method. In the final stage of the carbon thermal process, depending on the system composition, formation of iron carbide at 720 °C can occur with the possible subsequent conversion back to iron, as well as secondary oxidation of iron to form wustite. Carbon dioxide takes an active part in these reactions. Based on the results of calculations of chemical processes at high temperatures, a numerical assessment of the reducing (or oxidative) efficiency of all elements and components of the Fe – O – C – H system was given. This made it possible to predict with a high degree of reliability the phase composition of the reaction products at maximum process temperature (1500 °C).

Synthesis of Hard-Melting Carbide, Nitrite and Intermetallic Phases with Surface Electron-Beam Microallоying

2016 ◽  
Vol 876 ◽  
pp. 25-35 ◽  
Author(s):  
Mariuch Jenek ◽  
Sergey Voldemarovich Fedorov ◽  
Min Htet Swe
Keyword(s):  
Thin Film ◽  
Electron Beam ◽  
Chemical Reactions ◽  
Intermetallic Phases ◽  
Experimental Results ◽  
Reaction Products ◽  
Surface Electron ◽  
Wide Range ◽  
New Phase

The experimental results prove the ability to produce layers modified by microalloying with electron-beam technology using wide range of materials. Such layers were produced due to initiating exothermic chemical reactions between the base and the thin film covered the base. This resulted in finding new phase compounds in reaction products.

scholarly journals Key bioactive reaction products of the NO/H2S interaction are S/N-hybrid species, polysulfides, and nitroxyl

2015 ◽  
Vol 112 (34) ◽  
pp. E4651-E4660 ◽  
Author(s):  
Miriam M. Cortese-Krott ◽  
Gunter G. C. Kuhnle ◽  
Alex Dyson ◽  
Bernadette O. Fernandez ◽  
Marian Grman ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Chemical Reactions ◽  
Chemical Biology ◽  
Arterial Compliance ◽  
Cardiac Contractility ◽  
Reaction Products ◽  
Hybrid Species ◽  
Redox Switching

Experimental evidence suggests that nitric oxide (NO) and hydrogen sulfide (H2S) signaling pathways are intimately intertwined, with mutual attenuation or potentiation of biological responses in the cardiovascular system and elsewhere. The chemical basis of this interaction is elusive. Moreover, polysulfides recently emerged as potential mediators of H2S/sulfide signaling, but their biosynthesis and relationship to NO remain enigmatic. We sought to characterize the nature, chemical biology, and bioactivity of key reaction products formed in the NO/sulfide system. At physiological pH, we find that NO and sulfide form a network of cascading chemical reactions that generate radical intermediates as well as anionic and uncharged solutes, with accumulation of three major products: nitrosopersulfide (SSNO−), polysulfides, and dinitrososulfite [N-nitrosohydroxylamine-N-sulfonate (SULFI/NO)], each with a distinct chemical biology and in vitro and in vivo bioactivity. SSNO− is resistant to thiols and cyanolysis, efficiently donates both sulfane sulfur and NO, and potently lowers blood pressure. Polysulfides are both intermediates and products of SSNO− synthesis/decomposition, and they also decrease blood pressure and enhance arterial compliance. SULFI/NO is a weak combined NO/nitroxyl donor that releases mainly N2O on decomposition; although it affects blood pressure only mildly, it markedly increases cardiac contractility, and formation of its precursor sulfite likely contributes to NO scavenging. Our results unveil an unexpectedly rich network of coupled chemical reactions between NO and H2S/sulfide, suggesting that the bioactivity of either transmitter is governed by concomitant formation of polysulfides and anionic S/N-hybrid species. This conceptual framework would seem to offer ample opportunities for the modulation of fundamental biological processes governed by redox switching and sulfur trafficking.

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