Determination of Substitutional-Interstitial Interaction from Chemical Potentials of Interstitials in the Steel Matrix

2014 ◽  
Vol 922 ◽  
pp. 645-650
Author(s):  
Yao V. Shan ◽  
Jiří Svoboda ◽  
Franz Dieter Fischer ◽  
E. Kozeschnik
Keyword(s):  
Chemical Potential ◽  
Steel Matrix ◽  
Carbon And Nitrogen ◽  
Chemical Potentials ◽  
Substitutional Solute ◽  
Different Depths ◽  
Solute Atoms ◽  
The One ◽  
Trapping Sites

The interaction between interstitially diffusing atoms and substitutional solute atoms, acting as trapping sites, causes a non-negligible influence on the diffusion process itself and, consequently, on many aspects of alloys, such as phase transformations, solubility, precipitation of carbides and nitrides etc. The most important quantity in this treatment is the so-called trapping enthalpy (depth of trap), which has been used in several approaches in literature over the last century. However, the determination of the trapping enthalpy so far relies on approximations or assumptions on the one hand (statistical approaches, quasi chemical approach) or is significantly limited due to high complexity (ab initio approaches) on the other hand. The model introduced in this paper illustrates a rigorous and efficient thermodynamically-based concept utilizing only the dependence of the chemical potential of the interstitial component on the chemical composition of the alloy. Such a dependency is available in a very precise form from CALPHAD thermodynamic databases. Using the most recent databases available, the trapping enthalpies of carbon and nitrogen at various solute atoms (trapping sites) are evaluated for austenitic and ferritic steels. Good agreement with previous literature results is observed. The flexibility of the concept allows also for the treatment of trapping in a multi-component system, where different types of solute atoms are responsible for different depths of traps.

Depth Oscillations of Planar Channeling Yields in InP and GaP for Lattice Location Applications.

1988 ◽  
Vol 144 ◽  
Author(s):  
M.L. Swanson ◽  
N.R. Parikh ◽  
G.S. Sandhu ◽  
E.C. Frey ◽  
Z.H. Zhanc ◽  
...  
Keyword(s):  
Compound Semiconductors ◽  
Ion Beams ◽  
Lattice Location ◽  
Planar Channel ◽  
Planar Channeling ◽  
Diamond Structure ◽  
Different Depths ◽  
Solute Atoms ◽  
Atomic Species

ABSTRACTFor compound semiconductors with the diamond structure, (111) planar channel walls contain different atomic species when viewed from different sides; thus under channeling conditions, the yields of ions backscattered from the different species oscillate with depth in opposite senses for ion beams directed towards the different channel sides. We have studied this effect for 2 MeV He ions in a (111) channel of InP crystals. The application of this channeling phenomenon to the determination of the lattice sites of solute atoms was demonstrated for implanted In and Sb atoms at different depths in GaP.

scholarly journals QCD at finite isospin chemical potential

2018 ◽  
Vol 175 ◽  
pp. 07020 ◽  
Author(s):  
Bastian B. Brandt ◽  
Gergely Endrődi ◽  
Sebastian Schmalzbauer
Keyword(s):  
Taylor Expansion ◽  
Chemical Potential ◽  
Quark Masses ◽  
Monte Carlo Techniques ◽  
Chemical Potentials ◽  
Cosmological Application ◽  
Sign Problem ◽  
Charged Pions ◽  
First Results

We investigate the properties of QCD at finite isospin chemical potential at zero and non-zero temperatures. This theory is not affected by the sign problem and can be simulated using Monte-Carlo techniques. With increasing isospin chemical potential and temperatures below the deconfinement transition the system changes into a phase where charged pions condense, accompanied by an accumulation of low modes of the Dirac operator. The simulations are enabled by the introduction of a pionic source into the action, acting as an infrared regulator for the theory, and physical results are obtained by removing the regulator via an extrapolation. We present an update of our study concerning the associated phase diagram using 2+1 flavours of staggered fermions with physical quark masses and the comparison to Taylor expansion. We also present first results for our determination of the equation of state at finite isospin chemical potential and give an example for a cosmological application. The results can also be used to gain information about QCD at small baryon chemical potentials using reweighting with respect to the pionic source parameter and the chemical potential and we present first steps in this direction.

scholarly journals Solute–Solute Interaction In α IRON: The Status QUO

2015 ◽  
Vol 60 (3) ◽  
pp. 2061-2068 ◽  
Author(s):  
H. Numakura
Keyword(s):  
Experimental Methods ◽  
Status Quo ◽  
Carbon And Nitrogen ◽  
Theoretical Approaches ◽  
Quantitative Studies ◽  
Substitutional Solute ◽  
Solute Interaction ◽  
The Status ◽  
Solute Atoms ◽  
Snoek Relaxation

Abstract An overview is presented on the interaction of substitutional solutes with carbon and nitrogen in α iron, which is an important factor in controlling the properties of steels. Starting from a simple model of trapping of the interstitial solute atoms by substitutional solute atoms, the principles of experimental methods for quantitative studies are described, focussing on the Snoek relaxation and solubility measurements, and the knowledge acquired by such experiments is reviewed. An account of recent theoretical approaches to the interaction is also given.

Two-Stage Procedure for the Quantitative Determination of Autoprothrombin III Concentration and Some Applications

1967 ◽  
Vol 18 (01/02) ◽  
pp. 198-210 ◽  
Author(s):  
Ronald S Reno ◽  
Walter H Seegers
Keyword(s):  
Prothrombin Time ◽  
Factor Vii ◽  
Two Stage ◽  
Pronounced Increase ◽  
One Stage ◽  
Assay Procedure ◽  
Bovine Plasma ◽  
The One ◽  
Autoprothrombin C

SummaryA two-stage assay procedure was developed for the determination of the autoprothrombin C titre which can be developed from prothrombin or autoprothrombin III containing solutions. The proenzyme is activated by Russell’s viper venom and the autoprothrombin C activity that appears is measured by its ability to shorten the partial thromboplastin time of bovine plasma.Using the assay, the autoprothrombin C titre was determined in the plasma of several species, as well as the percentage of it remaining in the serum from blood clotted in glass test tubes. Much autoprothrombin III remains in human serum. With sufficient thromboplastin it was completely utilized. Plasma from selected patients with coagulation disorders was assayed and only Stuart plasma was abnormal. In so-called factor VII, IX, and P.T.A. deficiency the autoprothrombin C titre and thrombin titre that could be developed was normal. In one case (prethrombin irregularity) practically no thrombin titre developed but the amount of autoprothrombin C which generated was in the normal range.Dogs were treated with Dicumarol and the autoprothrombin C titre that could be developed from their plasmas decreased until only traces could be detected. This coincided with a lowering of the thrombin titre that could be developed and a prolongation of the one-stage prothrombin time. While the Dicumarol was acting, the dogs were given an infusion of purified bovine prothrombin and the levels of autoprothrombin C, thrombin and one-stage prothrombin time were followed for several hours. The tests became normal immediately after the infusion and then went back to preinfusion levels over a period of 24 hrs.In other dogs the effect of Dicumarol was reversed by giving vitamin K1 intravenously. The effect of the vitamin was noticed as early as 20 min after administration.In response to vitamin K the most pronounced increase was with that portion of the prothrombin molecule which yields thrombin. The proportion of that protein with respect to the precursor of autoprothrombin C increased during the first hour and then started to go down and after 3 hrs was equal to the proportion normally found in plasma.

SIMPLIFIED DEXAMETHASONE SUPPRESSION TEST

1969 ◽  
Vol 61 (2) ◽  
pp. 219-231 ◽  
Author(s):  
V. H. Asfeldt
Keyword(s):  
Cushing’S Syndrome ◽  
Normal Subjects ◽  
Cushing's Syndrome ◽  
Dexamethasone Suppression Test ◽  
Clinical Value ◽  
Suppression Test ◽  
The One ◽  
Steroid Excretion ◽  
Dexamethasone Suppression

ABSTRACT This is an investigation of the practical clinical value of the one mg dexamethasone suppression test of Nugent et al. (1963). The results, evaluated from the decrease in fluorimetrically determined plasma corticosteroids in normal subjects, as well as in cases of exogenous obesity, hirsutism and in Cushing's syndrome, confirm the findings reported in previous studies. Plasma corticosteroid reduction after one mg of dexamethasone in cases of stable diabetes was not significantly different from that observed in control subjects, but in one third of the insulin-treated diabetics only a partial response was observed, indicating a slight hypercorticism in these patients. An insufficient decrease in plasma corticosteroids was observed in certain other conditions (anorexia nervosa, pituitary adenoma, patients receiving contraceptive or anticonvulsive treatment) with no hypercorticism. The physiological significance of these findings is discussed. It is concluded that the test, together with a determination of the basal urinary 17-ketogenic steroid excretion, is suitable as the first diagnostic test in patients in whom Cushing's syndrome is suspected. In cases of insufficient suppression of plasma corticosteroids, further studies, including the suppression test of Liddle (1960), must be carried out.

Structure, Stability and Water Adsorption on Ultra-Thin TiO2 Supported on TiN

2019 ◽  
Author(s):  
Jose Julio Gutierrez Moreno ◽  
Marco Fronzi ◽  
Pierre Lovera ◽  
alan O'Riordan ◽  
Mike J Ford ◽  
...  
Keyword(s):  
Density Functional ◽  
Water Adsorption ◽  
Chemical Potential ◽  
Energy Gap ◽  
Molecular Water ◽  
Structure Stability ◽  
Ambient Conditions ◽  
Rutile Structure ◽  
The Stability ◽  
The One

<p></p><p>Interfacial metal-oxide systems with ultrathin oxide layers are of high interest for their use in catalysis. In this study, we present a density functional theory (DFT) investigation of the structure of ultrathin rutile layers (one and two TiO<sub>2</sub> layers) supported on TiN and the stability of water on these interfacial structures. The rutile layers are stabilized on the TiN surface through the formation of interfacial Ti–O bonds. Charge transfer from the TiN substrate leads to the formation of reduced Ti<sup>3+</sup> cations in TiO<sub>2.</sub> The structure of the one-layer oxide slab is strongly distorted at the interface, while the thicker TiO<sub>2</sub> layer preserves the rutile structure. The energy cost for the formation of a single O vacancy in the one-layer oxide slab is only 0.5 eV with respect to the ideal interface. For the two-layer oxide slab, the introduction of several vacancies in an already non-stoichiometric system becomes progressively more favourable, which indicates the stability of the highly non-stoichiometric interfaces. Isolated water molecules dissociate when adsorbed at the TiO<sub>2</sub> layers. At higher coverages the preference is for molecular water adsorption. Our ab initio thermodynamics calculations show the fully water covered stoichiometric models as the most stable structure at typical ambient conditions. Interfacial models with multiple vacancies are most stable at low (reducing) oxygen chemical potential values. A water monolayer adsorbs dissociatively on the highly distorted 2-layer TiO<sub>1.75</sub>-TiN interface, where the Ti<sup>3+</sup> states lying above the top of the valence band contribute to a significant reduction of the energy gap compared to the stoichiometric TiO<sub>2</sub>-TiN model. Our results provide a guide for the design of novel interfacial systems containing ultrathin TiO<sub>2</sub> with potential application as photocatalytic water splitting devices.</p><p></p>

A Validated 2D-LC-UV Method for Simultaneous Determination of Imatinib and N-demethylimatinib in Plasma and Its Clinical Application for Therapeutic Drug Monitoring with GIST Patients

2020 ◽  
Vol 17 ◽  
Author(s):  
Houli Li ◽  
Di Zhang ◽  
Xiaoliang Cheng ◽  
Qiaowei Zheng ◽  
Kai Cheng ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
One Dimension ◽  
Therapeutic Drug ◽  
Plasma Samples ◽  
Column Temperature ◽  
Injection Volume ◽  
Target Analytes ◽  
The One ◽  
Middle Column

Background: The trough concentration (Cmin) of Imatinib (IM) is closely related to the treatment outcomes and adverse reactions of patients with gastrointestinal stromal tumors (GIST). However, the drug plasma level has great interand intra-individual variability, and therapeutic drug monitoring (TDM) is highly recommended. Objective: To develop a novel, simple, and economical two-dimensional liquid chromatography method with ultraviolet detector (2D-LC-UV) for simultaneous determination of IM and its major active metabolite, N-demethyl imatinib (NDIM) in human plasma, and then apply the method for TDM of the drug. Method: Sample was processed by simple protein precipitation. Two target analytes were separated on the one-dimension column, captured on the middle column, and then transferred to the two-dimension column for further analysis. The detection was performed at 264 nm. The column temperature was maintained at 40˚C and the injection volume was 500 μL. Totally 32 plasma samples were obtained from patients with GIST who were receiving IM. Method: Sample was processed by simple protein precipitation. Two target analytes were separated on the one-dimension column, captured on the middle column, and then transferred to the two-dimension column for further analysis. The detection was performed at 264 nm. The column temperature was maintained at 40˚C and the injection volume was 500 μL. Totally 32 plasma samples were obtained from patients with GIST who were receiving IM. Conclusion: The novel 2D-LC-UV method is simple, stable, highly automated and independent of specialized technicians, which greatly increases the real-time capability of routine TDM for IM in hospital.

scholarly journals More on complex Sachdev-Ye-Kitaev eternal wormholes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Pengfei Zhang
Keyword(s):  
Black Hole ◽  
Ground State ◽  
Effective Action ◽  
Chemical Potential ◽  
Specific Charge ◽  
Zero Temperature ◽  
Small Coupling ◽  
Chemical Potentials ◽  
Quench Dynamics ◽  
Two Sides

Abstract In this work, we study a generalization of the coupled Sachdev-Ye-Kitaev (SYK) model with U(1) charge conservations. The model contains two copies of the complex SYK model at different chemical potentials, coupled by a direct hopping term. In the zero-temperature and small coupling limit with small averaged chemical potential, the ground state is an eternal wormhole connecting two sides, with a specific charge Q = 0, which is equivalent to a thermofield double state. We derive the conformal Green’s functions and determine corresponding IR parameters. At higher chemical potential, the system transit into the black hole phase. We further derive the Schwarzian effective action and study its quench dynamics. Finally, we compare numerical results with the analytical predictions.

scholarly journals The Concept of Accuracy Analysis of the Vertical Displacements Gained from the Hydrostatic Levelling Systems’ Measurements

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4842
Author(s):  
Waldemar Kamiński
Keyword(s):  
Accuracy Assessment ◽  
Theoretical Models ◽  
Vertical Displacement ◽  
Serial Connection ◽  
Vertical Displacements ◽  
Comprehensive Determination ◽  
The One ◽  
The Individual ◽  
Reference Sensor

Nowadays, hydrostatic levelling is a widely used method for the vertical displacements’ determinations of objects such as bridges, viaducts, wharfs, tunnels, high buildings, historical buildings, special engineering objects (e.g., synchrotron), sports and entertainment halls. The measurements’ sensors implemented in the hydrostatic levelling systems (HLSs) consist of the reference sensor (RS) and sensors located on the controlled points (CPs). The reference sensor is the one that is placed at the point that (in theoretical assumptions) is not a subject to vertical displacements and the displacements of controlled points are determined according to its height. The hydrostatic levelling rule comes from the Bernoulli’s law. While using the Bernoulli’s principle in hydrostatic levelling, the following components have to be taken into account: atmospheric pressure, force of gravity, density of liquid used in sensors places at CPs. The parameters mentioned above are determined with some mean errors that influence on the accuracy assessment of vertical displacements. In the subject’s literature, there are some works describing the individual accuracy analyses of the components mentioned above. In this paper, the author proposes the concept of comprehensive determination of mean error of vertical displacement (of each CPs), calculated from the mean errors’ values of components dedicated for specific HLS. The formulas of covariances’ matrix were derived and they enable to make the accuracy assessment of the calculations’ results. The author also presented the subject of modelling of vertical displacements’ gained values. The dependences, enabling to conduct the statistic tests of received model’s parameters, were implemented. The conducted tests make it possible to verify the correctness of used theoretical models of the examined object treated as the rigid body. The practical analyses were conducted for two simulated variants of sensors’ connections in HLS. Variant no. I is the sensors’ serial connection. Variant no. II relies on the connection of each CPs with the reference sensor. The calculations’ results show that more detailed value estimations of the vertical displacements can be obtained using variant no. II.

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