Unification of the Electronic Phase Diagrams of the RO1−xFxFeAs-Compounds by Using the Real Fluorine Content

2010 ◽  
Vol 1254 ◽  
Author(s):  
A. Köhler ◽  
G. Behr
Keyword(s):  
Phase Diagrams ◽  
Fluorine Content ◽  
Published Data ◽  
Initial Weight ◽  
X Ray ◽  
The Real ◽  
Electronic Phase ◽  
Consistent Picture ◽  
Good Agreement

AbstractMeasurements of the actual fluorine content x in the RO1−xFxFeAs-samples by wavelength-dispersive X-ray spectroscopy (WDX) reveal sample dependent discrepancies to the nominal fluorine content (initial weight). In particular for SmO1−xFxFeAs, the measured value only reached approximately half of the required value. In the lanthanum compound LaO1−xFxFeAs, we found a good agreement mainly for x>0.05, but the fluorine hardly goes into the sample for x<0.05. We used the measured fluorine content when plotting the electronic phase diagrams again and find a more consistent picture occurs as well for our samples as for comparison with the divers published data.

Vapour growth, morphology, absolute structure and pyroelectric coefficient of meta-nitroaniline single crystals

2019 ◽  
Vol 52 (3) ◽  
pp. 564-570 ◽  
Author(s):  
Rolf Hesterberg ◽  
Michel Bonin ◽  
Martin Sommer ◽  
Matthias Burgener ◽  
Bernhard Trusch ◽  
...  
Keyword(s):  
Room Temperature ◽  
Vapour Phase ◽  
Pyroelectric Coefficient ◽  
Growth Speed ◽  
Published Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Absolute Structure ◽  
Good Agreement

The growth speed of (hkl) faces in the vapour phase, the absolute structure obtained by X-ray crystallography, and the value and the sign of the pyroelectric coefficient of meta-nitroaniline (mNA) were analysed in detail. The in situ observation of morphologically well developed faces of several mNA crystals growing in evacuated ampoules reveals no pronounced growth speed anisotropy for polar faces defining the unique axis 2 of the mm2 group. Scanning pyroelectric microscopy confirms mono-domain mNA crystals. X-ray measurements in the space group Pca21 show that the molecular planes coincide with the {\bar 211} and {\bar 2\bar 1\bar 1} faces, and the nitro groups cover the {201} face in the opposite direction to the crystal tip, characterizing the polar habitus studied here. At room temperature, the sign of the pyroelectric coefficient is positive for a measured effective value of 6.3 µC m−2 K−1, in good agreement with values reported by other authors. From previous elastic and piezoelectric published data, the secondary pyroelectric effect was calculated to be positive and far greater than the effective one, yielding a negative value for the primary pyroelectric coefficient.

scholarly journals Performance Prediction Program for Wind-Assisted Cargo Ships

2021 ◽  
Vol 6 (01) ◽  
pp. 91-117
Author(s):  
Martina Reche-Vilanova ◽  
Heikki Hansen ◽  
Harry B. Bingham
Keyword(s):  
Performance Prediction ◽  
Ghg Emissions ◽  
Published Data ◽  
The Real ◽  
Prediction Program ◽  
Aerodynamic Database ◽  
Lift And Drag ◽  
Six Degree Of Freedom ◽  
Semi Empirical ◽  
Good Agreement

Wind-Assisted Propulsion Systems (WAPS) can play a key role in achieving the IMO 2050 targets on reducing the total annual GHG emissions from international shipping by at least 50%. The present project deals with the development of a six degree of freedom (DoF) Performance Prediction Program (PPP) for wind-assisted cargo ships aimed at contributing knowledge on WAPS performance. It is a fast and easy tool, able to predict the performance of any commercial ship with three possible different WAPS installed: rotor sails, rigid wing sails and DynaRigs; with only the ship main particulars and general dimensions as input data. The tool is based on semi-empirical methods and a WAPS aerodynamic database created from published data on lift and drag coefficients, which can be interpolated with the aim to scale to different sizes and configurations. A model validation is carried out to evaluate its reliability. The results are compared with the real sailing data of a Long Range 2 (LR2) class wind-assisted tanker vessel, the Maersk Pelican. The study indicates that the PPP shows good agreement with the technology suppliers’ own modelling tool and reasonable agreement with the trends of the real sailing measurements. However, for downwind sailing conditions, the predictions are more conservative than the measured values. Lastly, results showing and comparing power savings for the three different WAPS are presented. Rotor Sails are found to be the most efficient WAPS studied with a much higher potential of driving force generation per square meter of projected sail area.

scholarly journals Physical aspects of air disinfection

1951 ◽  
Vol 49 (4) ◽  
pp. 382-399 ◽  
Author(s):  
T. Nash
Keyword(s):  
Ternary System ◽  
Large Deviations ◽  
Phase Diagrams ◽  
The State ◽  
Published Data ◽  
Actual System ◽  
Consistent Picture ◽  
Independent Variable ◽  
Air Disinfection ◽  
The Ideal

A consistent picture of the state of a bacteria-carrying particle in a bactericidal atmosphere is given. The particle is referred to an ideal ternary system where two of the components are volatile and in equilibrium with their respective vapours. The ideal phase diagrams for systems with one independent variable are given, and the large deviations from the ideal of an actual system are shown from calculations using published data on salivary particle masses in the presence of bactericide vapour at various relative humidities.

Electrochemical behaviour of Co-doped LSGM perovskites prepared by sol-gel synthesis

2004 ◽  
Vol 835 ◽  
Author(s):  
Riccardo Polini ◽  
Alessia Falsetti ◽  
Enrico Traversa ◽  
Oliver Schäf ◽  
Philippe Knauth
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Sol Gel ◽  
Published Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Apparent Activation Energies ◽  
Sol Gel Synthesis ◽  
Perovskite Lattice ◽  
Good Agreement

ABSTRACTLa0.8Sr0.2Ga0.8Mg0.2-xCoxO3-δ (LSGMC) powders containing different amounts of Co (x = 0.05 and 0.085) were prepared by a citrate sol-gel method. Crystalline powders were obtained by firing at 1000°C (10 h) and dense high-purity pellets were prepared by pressing (300 MPa) and sintering in air at 1475°C (5, 10 and 20 h). The sintered pellets of LSGMC were characterized by X-Ray Diffraction (XRD) Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The conductivity of sintered LSGMC pellets containing different amounts of Co ions in the B sites of the perovskite lattice was assessed by electrochemical impedance spectroscopy (EIS) in the 250–750 °C temperature range. Conductivity values and apparent activation energies were in good agreement with previously published data referring to materials with same composition, but prepared by solid-state reaction.

Quantitative Measure of EM-Induced Drift in Sub-Micron Al Lines

1998 ◽  
Vol 516 ◽  
Author(s):  
C. Witt ◽  
C.A. Volkert
Keyword(s):  
Electron Microscope ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Quantitative Measure ◽  
Published Data ◽  
X Ray ◽  
A Value ◽  
Constant Rate ◽  
Scanning Electron ◽  
Good Agreement

AbstractElectromigration-induced drift in sub-micron wide Al segments has been measured using energy dispersive x-ray analysis in a scanning electron microscope. This technique, which works on both passivated and unpassivated samples, is sensitive to uniform Al displacements as small as 100 nm. The samples were 0.3 and 0.5 µm wide runners consisting of a continuous Ti/TiN line on top of which were patterned 0.4µm thick Al (0.5wt% Cu) segments of lengths varying between 5 and 100 µm. The microstructure, as determined by focused ion beam imaging, was predominantly bamboo. We have measured the Al depletion at the cathode ends of these segments after stressing for various times at 2 MA/cm2 at 200'C. For segments shorter than roughly 15 µm, no depletion occurred during the entire 100 hours of the experiment, yielding a value of the current-length threshold product of roughly 3000 A/cm, in agreement with previously published data. Longer segments (20-25 µm) depleted at a roughly constant rate for the duration of the experiment, yielding a drift velocity of around 3 nm/hr in the 0.5 µm wide lines, also in good agreement with published data for near-bamboo lines. However, the 0.3 µm wide lines drifted faster at roughly 6.5 nm/hr. The longest segments (50-100 µm), which started drifting at the same rate as the shorter segments, accelerated after 50 hours of testing to drift velocities in excess of 40 nm/hr. This may be associated with the depletion of Cu from the drifting end.

Transmission electron microscope studies in special ceramics

1978 ◽  
Vol 36 (1) ◽  
pp. 268-269
Author(s):  
A. Zangvil ◽  
L.J. Gauckler ◽  
G. Schneider ◽  
M. Rühle
Keyword(s):  
Phase Diagrams ◽  
Crystal Structures ◽  
Thin Foil ◽  
Limited Extent ◽  
Complex Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Lattice Resolution

The use of high temperature special ceramics which are usually complex materials based on oxides, nitrides, carbides and borides of silicon and aluminum, is critically dependent on their thermomechanical and other physical properties. The investigations of the phase diagrams, crystal structures and microstructural features are essential for better understanding of the macro-properties. Phase diagrams and crystal structures have been studied mainly by X-ray diffraction (XRD). Transmission electron microscopy (TEM) has contributed to this field to a very limited extent; it has been used more extensively in the study of microstructure, phase transformations and lattice defects. Often only TEM can give solutions to numerous problems in the above fields, since the various phases exist in extremely fine grains and subgrain structures; single crystals of appreciable size are often not available. Examples with some of our experimental results from two multicomponent systems are presented here. The standard ion thinning technique was used for the preparation of thin foil samples, which were then investigated with JEOL 200A and Siemens ELMISKOP 102 (for the lattice resolution work) electron microscopes.

Atomic Layer Deposition of LiF and Lithium Ion Conducting (AlF3)(LiF)x Alloys Using Trimethylaluminum, Lithium Hexamethyldisilazide and Hydrogen Fluoride

2017 ◽  
Author(s):  
Younghee Lee ◽  
Daniela M. Piper ◽  
Andrew S. Cavanagh ◽  
Matthias J. Young ◽  
Se-Hee Lee ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Atomic Layer ◽  
Mass Gain ◽  
Alloy Film ◽  
Ex Situ ◽  
X Ray ◽  
Layer Deposition ◽  
Ion Conducting ◽  
Good Agreement

<div>Atomic layer deposition (ALD) of LiF and lithium ion conducting (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloys was developed using trimethylaluminum, lithium hexamethyldisilazide (LiHMDS) and hydrogen fluoride derived from HF-pyridine solution. ALD of LiF was studied using in situ quartz crystal microbalance (QCM) and in situ quadrupole mass spectrometer (QMS) at reaction temperatures between 125°C and 250°C. A mass gain per cycle of 12 ng/(cm<sup>2</sup> cycle) was obtained from QCM measurements at 150°C and decreased at higher temperatures. QMS detected FSi(CH<sub>3</sub>)<sub>3</sub> as a reaction byproduct instead of HMDS at 150°C. LiF ALD showed self-limiting behavior. Ex situ measurements using X-ray reflectivity (XRR) and spectroscopic ellipsometry (SE) showed a growth rate of 0.5-0.6 Å/cycle, in good agreement with the in situ QCM measurements.</div><div>ALD of lithium ion conducting (AlF3)(LiF)x alloys was also demonstrated using in situ QCM and in situ QMS at reaction temperatures at 150°C A mass gain per sequence of 22 ng/(cm<sup>2</sup> cycle) was obtained from QCM measurements at 150°C. Ex situ measurements using XRR and SE showed a linear growth rate of 0.9 Å/sequence, in good agreement with the in situ QCM measurements. Stoichiometry between AlF<sub>3</sub> and LiF by QCM experiment was calculated to 1:2.8. XPS showed LiF film consist of lithium and fluorine. XPS also showed (AlF<sub>3</sub>)(LiF)x alloy consists of aluminum, lithium and fluorine. Carbon, oxygen, and nitrogen impurities were both below the detection limit of XPS. Grazing incidence X-ray diffraction (GIXRD) observed that LiF and (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film have crystalline structures. Inductively coupled plasma mass spectrometry (ICP-MS) and ionic chromatography revealed atomic ratio of Li:F=1:1.1 and Al:Li:F=1:2.7: 5.4 for (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film. These atomic ratios were consistent with the calculation from QCM experiments. Finally, lithium ion conductivity (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film was measured as σ = 7.5 × 10<sup>-6</sup> S/cm.</div>

A Calculation real abundance of gaseous elements of the comet PanSTARRS C/2011 S4

2020 ◽  
Vol 18 (45) ◽  
pp. 21-31
Author(s):  
Salman Zaidan Khalaf ◽  
Khaleel Abrahim ◽  
Imad Kassar Akeab
Keyword(s):  
Solar Wind ◽  
Physical Properties ◽  
Atomic Number ◽  
Mathematic Model ◽  
Emission Energy ◽  
X Ray ◽  
The Real

    X-ray emission contains some of the gaseous properties is produced when the particles of the solar wind strike the atmosphere of comet ISON and PanSTARRS Comets. The data collected with NASA Chandra X-ray Observatory of the two comets, C/2012 S1 (also known as Comet ISON) and C/2011 S4 (Comet PanSTARRS) are used in this study.    The real abundance of the observed X-ray spectrum elements has been extracted by a new simple mathematic model. The study found some physical properties of these elements in the comet’s gas such as a relationship between the abundance with emitted energy. The elements that have emission energy (2500-6800) eV, have abundance (0.1-0.15) %, while the elements that have emission energy (850-2500) eV and (6800-9250) eV have abundance (0.2-0.3) %.    The relation between interacted energy and atomic number is form two sets.  The interacted energy of each element is increased as the atomic number increased. This case has been seen in both comets

A DFT study of spherands containing five anisyl groups — Highly preorganized to bind the alkali metal

2006 ◽  
Vol 84 (8) ◽  
pp. 1045-1049 ◽  
Author(s):  
Shabaan AK Elroby ◽  
Kyu Hwan Lee ◽  
Seung Joo Cho ◽  
Alan Hinchliffe
Keyword(s):  
Density Functional Theory ◽  
Binding Energy ◽  
Density Functional ◽  
Ionic Radius ◽  
Binding Energies ◽  
Cavity Size ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Good Agreement

Although anisyl units are basically poor ligands for metal ions, the rigid placements of their oxygens during synthesis rather than during complexation are undoubtedly responsible for the enhanced binding and selectivity of the spherand. We used standard B3LYP/6-31G** (5d) density functional theory (DFT) to investigate the complexation between spherands containing five anisyl groups, with CH2–O–CH2 (2) and CH2–S–CH2 (3) units in an 18-membered macrocyclic ring, and the cationic guests (Li+, Na+, and K+). Our geometric structure results for spherands 1, 2, and 3 are in good agreement with the previously reported X-ray diffraction data. The absolute values of the binding energy of all the spherands are inversely proportional to the ionic radius of the guests. The results, taken as a whole, show that replacement of one anisyl group by CH2–O–CH2 (2) and CH2–S–CH2 (3) makes the cavity bigger and less preorganized. In addition, both the binding and specificity decrease for small ions. The spherands 2 and 3 appear beautifully preorganized to bind all guests, so it is not surprising that their binding energies are close to the parent spherand 1. Interestingly, there is a clear linear relation between the radius of the cavity and the binding energy (R2 = 0.999).Key words: spherands, preorganization, density functional theory, binding energy, cavity size.

scholarly journals The influence of exocyclic lone pairs on the bonding and geometry of type A mesoionic rings

2021 ◽  
Author(s):  
Christopher Antony Ramsden ◽  
Wojciech Piotr Oziminski
Keyword(s):  
Ab Initio ◽  
Type A ◽  
Nbo Analysis ◽  
Ring Systems ◽  
X Ray ◽  
X Ray Crystallography ◽  
Bond Model ◽  
Lone Pairs ◽  
Mp2 Calculations ◽  
Good Agreement

AbstractBased on structures determined by X-ray crystallography, ab initio MP2 calculations on type A mesoionic rings give geometries in good agreement with observed values. A study of four mesoionic ring systems, each with exocyclic oxygen, nitrogen or carbon groups, shows that the presence and configuration of exocyclic lone pairs significantly influences the geometry and configurational preference. Using a localised bond model and NBO analysis, these effects are rationalised in terms of an anomeric interaction of lone pairs with the antibonding orbitals of adjacent σ bonds. In agreement with experiment, similar effects are calculated for pyran-2-imines.

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