scholarly journals Temperature Dependent Structural Evolution of WSe2: A Synchrotron X-ray Diffraction Study

2020 ◽  
Vol 5 (4) ◽  
pp. 76
Author(s):  
Sinu Mathew ◽  
Aben Regi Abraham ◽  
Sandhya Chintalapati ◽  
Soumya Sarkar ◽  
Boby Joseph ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Structural Parameters ◽  
Bond Distance ◽  
Structural Evolution ◽  
Nonlinear Behavior ◽  
Lattice Parameters ◽  
Prismatic Structure ◽  
System A ◽  
Significant Difference ◽  
Out Of Plane

A thorough investigation of the structural parameters of micromechanically exfoliated multilayer WSe2 flakes was undertaken between 400 K to 110 K. Crystal structure of WSe2 remains in the trigonal prismatic structure in this temperature range, however, with a clear difference in the temperature dependence of the in-plane a, and the out-of-plane c, lattice parameters. The linear coefficients of thermal expansion of a and c are 5.132 × 10−6/K and 8.105 × 10−6/K, respectively. The temperature dependence of the unit-cell volume is analyzed using zero-pressure equation-of-state which yielded the Debye temperature of the WSe2 to be 160 K. Following the temperature dependence of the W-Se and W-W bond distances, a nonlinear behavior is observed in the former in contrast to a rather regular behavior of the later. This significant difference in the temperature dependence of the a and c lattice parameters can have consequences in the macroscopic physical properties of the system. A good correlation between the temperature dependence of the W-Se bond distance and Raman E2g1 mode has been observed.

scholarly journals Surface Tension and Density of Liquid Hot Work Tool Steel W360 by voestalpine BÖHLER Edelstahl GmbH & Co KG Measured with an Electromagnetic Levitation Apparatus

2020 ◽  
Vol 42 (2) ◽  
Author(s):  
Thomas Leitner ◽  
Anna Werkovits ◽  
Siegfried Kleber ◽  
Gernot Pottlacher
Keyword(s):  
Surface Tension ◽  
Temperature Dependence ◽  
Linear Model ◽  
Tool Steel ◽  
Pure Iron ◽  
Electromagnetic Levitation ◽  
Liquid Density ◽  
Hot Work Tool Steel ◽  
Significant Difference ◽  
Main Component

AbstractW360 is a hot work tool steel produced by voestalpine BÖHLER Edelstahl GmbH & Co KG, a special steel producer located in Styria, Austria. Surface tension and density of liquid W360 were studied as a function of temperature in a non-contact, containerless fashion using the oscillating drop method inside an electromagnetic levitation setup. For both, surface tension and density, a linear model was adapted to present the temperature dependence of these measures, including values for the uncertainties of the fit parameters found. The data obtained are compared to pure iron (with 91 wt% the main component of W360), showing an overlap for the liquid density while there is a significant difference in surface tension (− 5.8 % at the melting temperature of pure iron of 1811 K).

scholarly journals Crystallographic and structural characterization of heterometallic platinum compounds Part VII. Heterohepta- and heterooctanuclear clusters

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Milan Melnik ◽  
Peter Mikuš ◽  
Clive E. Holloway
Keyword(s):  
Structural Characterization ◽  
Structural Parameters ◽  
Bond Distance ◽  
Point Of View ◽  
Platinum Compounds ◽  
Metal Atoms ◽  
Platinum Clusters ◽  
Structural Point

AbstractThis review classifies and analyzes over fifty heterohepta- and heterooctanuclear platinum clusters. There are eight types of metal combinations in heteroheptanuclear: Pt6M, Pt5M2, Pt4M3, Pt3M4, Pt2M5, PtM6, Pt3Hg2Ru2 and Pt2Os3Fe2. The seven metal atoms are in a wide variety of arrangements, with the most common being one in which the central M atom (mostly M(I)) is sandwiched by two M3 triangles. Another arrangement often found is an octahedron of M6 atoms asymmetrically capped by an M atom. The shortest Pt-M bond distances (non-transition and transition) are 2.326(1) Å (M = Ga) and 2.537(6) Å (M = Fe). The shortest Pt-Pt bond distance is 2.576(2) Å.In heterooctanuclear platinum clusters there are eight types of metal combinations: Pt6M2, Pt4M4, Pt3Ru5, Pt2M6, PtM7, Pt2W4Ni2, PtAu6Hg and PtAu5Hg2. From a structural point of view, the clusters are complex with bicapped octahedrons of eight metal atoms prevailing. The shortest Pt-M bond distances (non-transition and transition) are 2.651(3) Å (M = Hg) and 2.624(1) Å (M = Os). The shortest Pt-Pt bond distance is 2.622(1) Å. These values are somewhat longer than those in the heteroheptanuclear clusters. Several relationships between the structural parameters were found, and are discussed and compared with the smaller heterometallic platinum clusters

scholarly journals Crystallographic and structural characterization of heterometallic platinum complexes Part VI. Heterohexanuclear complexes

2014 ◽  
Vol 12 (11) ◽  
pp. 1101-1126 ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš ◽  
Clive Holloway
Keyword(s):  
Metal Ion ◽  
Structural Parameters ◽  
Bond Distance ◽  
Transition Element ◽  
Platinum Complexes ◽  
Hard Metals ◽  
Wide Range ◽  
Platinum Clusters ◽  
Soft Metal ◽  
Independent Molecules

AbstractThis review classifies and analyzes heterohexanuclear platinum clusters into seven types of metal combinations:Pt5M, Pt4M2, Pt3M3, Pt2M4, PtM5, Pt2M3M′, and Pt2M2M2′. The crystals of these clusters generally belong to six crystal classes: monoclinic, triclinic, orthorhombic, tetragonal, trigonal and cubic. Among the wide range of stereochemistry adopted by these clusters, octahedral and capped square-pyramidal are the most common. Although platinum is classified as a soft metal atom, it bonds to a variety of soft, borderline and hard metals. Nineteen different heterometal ions are involved in hexanuclear platinum clusters. The shortest Pt-M bond distance in the case of M being a non-transition element is 2.395(4) Å for germanium and for M being a transition metal ion it is 2.402(2) Å for Cobalt. The shortest Pt-Pt bond distance observed in these clusters is 2.532 Å. Several relationships between the structural parameters are identified and discussed. Some clusters exist in two isomeric forms and some show crystallographically independent molecules within the same crystal. Such isomers and independent molecules are examples of distortion isomerism.

scholarly journals Temperature-Driven Spin Reorientation Transition in CoPt/AlN Multilayer Films

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Wupeng Cai ◽  
Shinji Muraishi ◽  
Ji Shi ◽  
Yoshio Nakamura ◽  
Wei Liu ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Mean Field ◽  
Multilayer Films ◽  
Spin Reorientation ◽  
Strong Temperature Dependence ◽  
Mean Field Model ◽  
Spin Reorientation Transition ◽  
Magnetoelastic Effect ◽  
Out Of Plane ◽  
Interface Anisotropy

Spin reorientation transition phenomena from out-of-plane to in-plane direction with increasing temperature are observed for the 500°C annealed CoPt/AlN multilayer films with different CoPt layer thicknesses. CoPt-AlN interface and volume anisotropy contributions, favoring out-of-plane and in-plane magnetization, respectively, are separately determined at various temperatures. Interface anisotropy exhibits much stronger temperature dependence than volume contribution, hence the temperature-driven spin reorientation transition occurs. Interface anisotropy in this work consists of Néel interface anisotropy and magnetoelastic effect. Magnetoelastic effect degrades rapidly and changes its sign from positive to negative above 200°C, because of the involvement of stress state in CoPt films with temperature. By contrast, Néel interface anisotropy decays slowly, estimated from a Néel mean field model. Thus, the strong temperature dependence of CoPt-AlN interface anisotropy is dominated by the change of magnetoelastic effect.

SOFTENING BRANCHES OF A TWO-DEGREE-OF-FREEDOM SYSTEM INDUCED BY SPATIAL BUCKLING

2006 ◽  
Vol 06 (04) ◽  
pp. 493-512 ◽  
Author(s):  
NOËL CHALLAMEL
Keyword(s):  
Structural Model ◽  
Structural Parameters ◽  
Degree Of Freedom ◽  
Lateral Loading ◽  
Load Parameter ◽  
Imperfection Sensitivity ◽  
Softening Effect ◽  
Out Of Plane ◽  
Secondary Bifurcation ◽  
Two Degree Of Freedom

The aim of this paper is to show how geometrical non-linearity may induce equivalent softening in a simple two-degree-of-freedom spatial elastic system. The generic structural model studied is a generalization of Augusti's spatial model, incorporating lateral loading. This model could be used as a teaching model to understand the softening effect induced by out-of-plane buckling. The lateral loading in the plane of maximal stiffness is considered as the varying load parameter, whereas the vertical load is perceived as a constant parameter. It is shown that a bifurcation occurs at the critical horizontal load. The fundamental path becomes unstable, beyond this critical value. However, two symmetrical bifurcate solutions appear, whose stability depend on the structural parameters value. No secondary bifurcation is observed for this system. The presented system possesses imperfection sensitivity, and imperfection insensitivity, depending on the values of the structural parameters. In any case, for sufficiently large rotations, collapse occurs with unstable softening branches induced by spatial buckling.

A NEW METHOD OF DETERMINING THRESHOLD OF GENE NETWORK BASED ON PHENOTYPES

2011 ◽  
Vol 19 (04) ◽  
pp. 607-616
Author(s):  
YUANYUAN ZHANG ◽  
SHUDONG WANG ◽  
MEIXI YANG ◽  
DASHUN XU ◽  
DAZHI MENG
Keyword(s):  
Gene Networks ◽  
Gene Network ◽  
Structural Parameters ◽  
Network Modeling ◽  
Genetic Diseases ◽  
Disease Stage ◽  
External Representation ◽  
Functional Relationships ◽  
Disease Phenotypes ◽  
Significant Difference

With the rapid growth of microarray data, it has become a hot topic to reveal complex behaviors and functions of life system by studying the relationships among genes. In the process of reverse network modeling, the relationships with less relevance are generally not considered by determining a threshold when the relationships among genes are mined. However, there are no effective methods to determine the threshold up to now. It is worthwhile to note that the phenotypes of genetic diseases are generally regarded as external representation of the functions of genes. Therefore, two types of phenotype networks are constructed from gene and disease views, respectively, and through comparing these two types of phenotype networks, the threshold of gene network corresponding to a certain disease can be determined when their similarity reaches to maximum. Because the gene network is determined based on the relationships among phenotypes and phenotypes are external representation of the functions of genes, it is considered that relationships in the gene network may show functional relationships among genes in biological system. In this work, the thresholds 0.47 and 0.48 of gene network are determined based on Parkinson disease phenotypes. Furthermore, the validity of these thresholds is verified by the specificity and susceptibility of phenotype networks. Also, through comparing the structural parameters of gene networks for normal and disease stage at different thresholds, significant difference between the two gene networks at threshold 0.47 or 0.48 is found. The significant difference of structural parameters further verifies the efficiency of this method.

scholarly journals Morphological and Structural Evolution of Chemically Deposited Epitaxially LaNiO3 Thin Films

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1376
Author(s):  
Mircea Nasui ◽  
Ramona Bianca Sonher ◽  
Ecaterina Ware ◽  
Andrada Daniel ◽  
Traian Petrisor ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Analyses ◽  
Structural Evolution ◽  
Precursor Solution ◽  
Solution Deposition ◽  
Chemical Solution Deposition Method ◽  
Out Of Plane ◽  
Optimal Surface ◽  
Decomposition Behavior ◽  
Surface Morphologies

We report the preparation and characterization of epitaxial LaNiO3 (LNO) thin films by chemical solution deposition method using lanthanum and nickel acetylacetonates as starting reagents dissolved in propionic acid. In order to obtain further information regarding the decomposition behavior of the film, the precursor solution was dried to obtain the precursor powder, which was investigated by thermal analyses and X-ray diffraction measurements (XRD). The LNO perovskite thin films were deposited by spin coating on SrTiO3(100) single crystal substrates. A detailed study with different crystallization temperatures (600–900 °C) at two different heating ramps (5 and 10 °C/min) was performed. Oriented LaNiO3 thin films with good out-of-plane textures were obtained with optimal surface morphologies.

scholarly journals The assessment of the stability of the corneal structure after LASIK correction of myopia by different optical zone diameters

2016 ◽  
Vol 73 (6) ◽  
pp. 572-576 ◽  
Author(s):  
Milorad Milivojevic ◽  
Vladimir Petrovic ◽  
Miroslav Vukosavljevic ◽  
Ivan Marjanovic ◽  
Mirko Resan
Keyword(s):  
Structural Parameters ◽  
Preoperative Assessment ◽  
Laser In Situ Keratomileusis ◽  
Group I ◽  
Significant Difference ◽  
Optical Zone ◽  
Corneal Structure ◽  
The Stability ◽  
Corneal Thinning

Background/Aim. Enlargement of optical zone (OZ) diameter during laser in situ keratomileusis (LASIK) correction of myopia postoperatively improves the optical outcome, however, it also leads to the increased stroma tissue consumption - progressive corneal thinning. The aim of this investigation was to present the possibility of safe OZ enlargement without impairing the structural stability of the cornea, while obtaining an improved optical outcome with LASIK treatment of shortsightedness. Methods. Preoperative assessment of the cornea structure and prediction of the ablated stroma tissue consumption was conducted in 37 patients (74 eyes) treated for shortsightedness by means of the LASIK method. With the eyes that, according to their cornea structure, had the capacity for OZ diameter enlargement of 0.5 mm, LASIK treatment was performed within the wider OZ diameter of 7.0 mm compared to the standard 6.5 mm. The following two groups were formed, depending on the diameter of the utilized OZ: the group I (the eyes treated with the OZ 6.5 mm, n = 37) and the group II (the eyes treated with the OZ 7.0 mm, n = 37). Results. No significant difference in the observed structural parameters of the cornea was detected between the groups of patients treated with different OZ diameters. The values of all the parameters were significantly bellow the threshold values for the development of postoperative ectasia. Conclusion. Diameter enlargement of the treated OZ, if there is a preoperative cornea capacity for such enlargement, will not impair the postoperative stability of the cornea structure, and will significantly improve the optical outcome.

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