CALCULATION AND PLOTTING OF STANDARD FREE ENERGY CHANGES AND EQUILIBRIUM CONSTANTS FOR CVD HARD COATINGS REACTIONS

2005 ◽  
Vol 12 (05n06) ◽  
pp. 727-731 ◽  
Author(s):  
SHA LIU ◽  
JING QIU ZHANG
Keyword(s):  
Free Energy ◽  
Computer Program ◽  
Equilibrium Constants ◽  
Standard Free Energy ◽  
Chemical Vapor ◽  
Hard Coatings ◽  
Accurate Calculation ◽  
Materials Synthesis ◽  
Synthesis And Processing ◽  
General Computer Program

CVD (chemical vapor deposition) coatings such as TiC , TiN , Al 2 O 3 and so on are widely used as tools' surface preserved materials with corrosion resistance and wear resistance. Standard Gibbs free energy changes for reactions are widely used to approximately analyze the trends of substance reactions and phase transitions in chemical reactions, metallurgy processes, materials synthesis and processing. Hard coatings and thin films can be prepared by CVD process. Accurate calculation and plotting of the standard free energy changes and equilibrium constants for CVD TiC , TiN , Al 2 O 3 coatings reactions are realized using the developed general computer program. Only inputting the basic thermodynamic data tabulated in data books into the computer program, the relationships of the standard free energy changes and equilibrium constants for most reactions with the temperatures can be gained in the same diagrams.

scholarly journals The equilibrium constants of the glutamate dehydrogenase systems

1967 ◽  
Vol 105 (2) ◽  
pp. 691-695 ◽  
Author(s):  
P. C. Engel ◽  
K. Dalziel
Keyword(s):  
Free Energy ◽  
Ionic Strength ◽  
Glutamate Dehydrogenase ◽  
Thermodynamic Data ◽  
Equilibrium Constants ◽  
Standard Free Energy ◽  
Free Energy Change ◽  
Energy Change ◽  
Heat Of Reaction ◽  
Standard Free Energy Change

1. Equilibrium constants for the oxidation of glutamate by NAD+ and NADP+, catalysed by glutamate dehydrogenase, have been measured in phosphate buffers of different ionic strengths and at several temperatures. 2. The equilibrium constants for both systems vary markedly with ionic strength. Thermodynamic values for the two systems obtained by extrapolation to zero ionic strength differ significantly from one another. The standard free-energy change for NADP+ reduction has been calculated from that for NAD+ reduction. 3. The heat of reaction has been estimated and is the same with both coenzymes. 4. The thermodynamic data are discussed in relation to earlier data.

Calcium-zinc and calcium-cadmium exchange in suspensions of various types of clays

Clay Minerals ◽  
1993 ◽  
Vol 28 (1) ◽  
pp. 33-38 ◽  
Author(s):  
R. van Bladel ◽  
H. Halen ◽  
P. Cloos
Keyword(s):  
Heavy Metals ◽  
Free Energy ◽  
Ionic Strength ◽  
Clay Minerals ◽  
Thermodynamic Equilibrium ◽  
Equilibrium Constants ◽  
Standard Free Energy ◽  
Exchangeable Cation ◽  
Adsorption Sites ◽  
Complete Exchange

AbstractCalcium-cadmium and calcium-zinc exchange equilibria were studied at 20°C and constant ionic strength (0·015) on four clay minerals, viz. montmorillonite, bentonite, illite and vermiculite. Vermiculite and, to a lesser extent, illite and bentonite showed the strongest affinity for Cd2+ or Zn2+ over Ca2+ ions, whereas on the Camp Berteau montmorillonite nearly nonpreferential exchange isotherms were observed. With this one exception, selectivity for the heavy metals was greatly enhanced in the trace Cd or Zn regions, suggesting the presence of specific adsorption sites in these clays. Generally, the adsorption increased with the polarizing power of the exchangeable cation. Thermodynamic equilibrium constants and standard free energy changes for the complete exchange of Ca-clay to Cd- or Zn-clay were calculated.

A general computer program for the extended plate overlap algorithm

1978 ◽  
Vol 48 ◽  
pp. 287-293 ◽  
Author(s):  
Chr. de Vegt ◽  
E. Ebner ◽  
K. von der Heide
Keyword(s):  
Computer Program ◽  
Simultaneous Determination ◽  
General Computer Program ◽  
General Computer

In contrast to the adjustment of single plates a block adjustment is a simultaneous determination of all unknowns associated with many overlapping plates (star positions and plate constants etc. ) by one large adjustment. This plate overlap technique was introduced by Eichhorn and reviewed by Googe et. al. The author now has developed a set of computer programmes which allows the adjustment of any set of contemporaneous overlapping plates. There is in principle no limit for the number of plates, the number of stars, the number of individual plate constants for each plate, and for the overlapping factor.

scholarly journals Controlled Fabrication of Quality ZnO NWs/CNTs and ZnO NWs/Gr Heterostructures via Direct Two-Step CVD Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1836
Author(s):  
Nicholas Schaper ◽  
Dheyaa Alameri ◽  
Yoosuk Kim ◽  
Brian Thomas ◽  
Keith McCormack ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Chemical Vapor ◽  
Single Walled Carbon Nanotubes ◽  
Materials Synthesis ◽  
Oxide Nanowires ◽  
Cvd Method ◽  
Thermal Actuators ◽  
Potential Applications ◽  
Walled Carbon Nanotubes ◽  
Scalable Production

A novel and advanced approach of growing zinc oxide nanowires (ZnO NWs) directly on single-walled carbon nanotubes (SWCNTs) and graphene (Gr) surfaces has been demonstrated through the successful formation of 1D–1D and 1D–2D heterostructure interfaces. The direct two-step chemical vapor deposition (CVD) method was utilized to ensure high-quality materials’ synthesis and scalable production of different architectures. Iron-based universal compound molecular ink was used as a catalyst in both processes (a) to form a monolayer of horizontally defined networks of SWCNTs interfaced with vertically oriented ZnO NWs and (b) to grow densely packed ZnO NWs directly on a graphene surface. We show here that our universal compound molecular ink is efficient and selective in the direct synthesis of ZnO NWs/CNTs and ZnO NWs/Gr heterostructures. Heterostructures were also selectively patterned through different fabrication techniques and grown in predefined locations, demonstrating an ability to control materials’ placement and morphology. Several characterization tools were employed to interrogate the prepared heterostructures. ZnO NWs were shown to grow uniformly over the network of SWCNTs, and much denser packed vertically oriented ZnO NWs were produced on graphene thin films. Such heterostructures can be used widely in many potential applications, such as photocatalysts, supercapacitors, solar cells, piezoelectric or thermal actuators, as well as chemical or biological sensors.

scholarly journals Autonomous reinforcement learning agent for chemical vapor deposition synthesis of quantum materials

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pankaj Rajak ◽  
Aravind Krishnamoorthy ◽  
Ankit Mishra ◽  
Rajiv Kalia ◽  
Aiichiro Nakano ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Reinforcement Learning ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Time Behavior ◽  
Materials Synthesis ◽  
Design Synthesis ◽  
Learning Agent ◽  
Threshold Temperatures ◽  
Quantum Materials

AbstractPredictive materials synthesis is the primary bottleneck in realizing functional and quantum materials. Strategies for synthesis of promising materials are currently identified by time-consuming trial and error and there are no known predictive schemes to design synthesis parameters for materials. We use offline reinforcement learning (RL) to predict optimal synthesis schedules, i.e., a time-sequence of reaction conditions like temperatures and concentrations, for the synthesis of semiconducting monolayer MoS2 using chemical vapor deposition. The RL agent, trained on 10,000 computational synthesis simulations, learned threshold temperatures and chemical potentials for onset of chemical reactions and predicted previously unknown synthesis schedules that produce well-sulfidized crystalline, phase-pure MoS2. The model can be extended to multi-task objectives such as predicting profiles for synthesis of complex structures including multi-phase heterostructures and can predict long-time behavior of reacting systems, far beyond the domain of molecular dynamics simulations, making these predictions directly relevant to experimental synthesis.

Adsorption of Liquids and Swelling of Wood. Part VI. Saturated Amounts and Some Thermodynamic Values of Adsorption

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 91-97
Author(s):  
Kei Morisato ◽  
Yutaka Ishimaru ◽  
Hiroyuki Urakami
Keyword(s):  
Free Energy ◽  
Standard Free Energy ◽  
Molecular Size ◽  
Free Energy Change ◽  
Energy Change ◽  
Multilayer Adsorption ◽  
Monolayer Adsorption ◽  
Wood Part ◽  
Cohesive Interaction

Summary To understand the swelling phenomenon of wood in liquids,the saturated amount of adsorption of liquids onto wood and the standard free energy changes of the adsorption were determined. The saturated amount of adsorption obtained by regression for several liquids decreased with increasing molecular size of the solvents. The mechanism of wood swelling is discussed systematically taking all the liquids examined in previous experiments into account. Since methanol molecules require more energy for release from cohesive interactions within bulk liquids in the adsorption onto pre-swollen wood,the values of free energy change of adsorption for methanol were lower than the values for acetone,although the relative swelling with methanol was higher. These results suggest that although the cohesive interaction within the bulk liquids reduces adsorptivity,the phenomenon of wood swelling is influenced not only by monolayer adsorption but also by multilayer adsorption. Therefore,the cohesive interaction within the bulk liquids reduces adsorptivity but enhances the condensation which strongly influences the swelling of wood.

The Equilibrium and the Determination of D00 (H—CN)

1975 ◽  
Vol 53 (16) ◽  
pp. 2365-2370 ◽  
Author(s):  
Don Betowski ◽  
Gervase Mackay ◽  
John Payzant ◽  
Diethard Bohme
Keyword(s):  
Free Energy ◽  
Standard Enthalpy ◽  
Transfer Reaction ◽  
Standard Free Energy ◽  
Proton Transfer Reaction ◽  
Enthalpy Change ◽  
Standard Free Energy Change ◽  
Flowing Afterglow ◽  
Standard Enthalpy Change

The rate constants and equilibrium constant for the proton transfer reaction [Formula: see text] have been measured at 296 ± 2 K using the flowing afterglow technique: kforward = (2.9 ± 0.6) × 10−9 cm3molecule−1s−1, kreverse = (1.8 ± 0.4) × 10−10 cm3 molecule1 s−1, and K = 16 ± 2. The measured value of K corresponds to a standard free energy change, ΔG296°, of −1.6 ± 0.1 kcal mol−1 which provides values for the standard enthalpy change, ΔH298°= −1.0 ± 0.2 kcal mol−1, the bond dissociation energy, D00(H—CN) = 124 ± 2 kcal mol−1, and the proton affinity, p.a.(CN−) = 350 ± 1 kcal mol−1.

Accurate Calculation of Stress Distributions in Multiholed Plates

1965 ◽  
Vol 87 (3) ◽  
pp. 331-335 ◽  
Author(s):  
L. E. Hulbert ◽  
F. W. Niedenfuhr
Keyword(s):  
Computer Program ◽  
Plane Stress ◽  
Symmetric Groups ◽  
Thin Plates ◽  
Stress Distributions ◽  
Accurate Calculation ◽  
Point Matching ◽  
Shallow Shells ◽  
Matching Technique ◽  
Stress Functions

This paper discusses the application of the point-matching technique in obtaining the solution of many problems involving multiholed thin plates undergoing generalized plane stress. The stress functions appropriate to plates with symmetric groups of holes are described. A large number of problems solved by a computer program are described and compared with published results. Problems are solved also for which there are no known published results. Two interesting new problems are discussed in detail. The results show the power and flexibility of the technique. The extension of the methods to permit the solution of problems in the deflection of thin, multiholed plates and shallow shells is discussed.

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