250 research outputs found
Cationic order versus La-O covalency in LaA (Ca,Ba) VMoO6 double perovskites
No full textWe have investigated the structural and physical properties of double perovskite (DP) LaAVMoO6 (A=Ca2+, Ba2+; abbreviated as LCVMO and LBVMO from now on) compounds, proposed to be possible half-metallic antiferromagnets (HMAFMs). Here we show that within LaAVMoO6 double perovskite structure, La-O covalency competes against B-site as well A-site cationic order and this competition critically influences their physical properties. Evidently, the presence of Ca2+ or Ba2+ at the A site along with La3+ would offer a tool to modify the A-site ordering and consequently influence the La-O covalency as well. Our experimental results reveal that LCVMO lies at the extreme end of this family and accommodates large scale phase separation in terms of La, V, and Ca, Mo-rich phases as a result of dominant La-O covalency. On the other hand, LBVMO is more correctly described as a layered A-site ordered and nearly complete B-site disordered double perovskite where cationic order dominates the La-O covalency. The general trend of our experimental findings is in agreement with the ab initio electronic structure calculations, carried out on realistic structures based on local coordination obtained from extended x-ray-absorption fine-structure study
ARCH-COMP22 Category Report: Hybrid Systems with Piecewise Constant Dynamics and Bounded Model Checking
No full textDevelopment of half metallicity within mixed magnetic phase of Cu1-xCoxMnSb alloy
No full textCubic half-Heusler Cu1-xCoxMnSb () compounds have been investigated both experimentally and theoretically for their magnetic, transport and electronic properties in search of possible half metallic antiferromagnetism. The systems (Cu,Co)MnSb are of particular interest as the end member alloys CuMnSb and CoMnSb are semi metallic (SM) antiferromagnetic (AFM) and half metallic (HM) ferromagnetic (FM), respectively. Clearly, Co-doping at the Cu-site of CuMnSb introduces changes in the carrier concentration at the Fermi level that may lead to half metallic ground state but there remains a persistent controversy whether the AFM to FM transition occurs simultaneously. Our experimental results reveal that the AFM to FM magnetic transition occurs through a percolation mechanism where Co-substitution gradually suppresses the AFM phase and forces FM polarization around every dopant cobalt. As a result a mixed magnetic phase is realized within this composition range while a nearly HM band structure is developed already at the 10% Co-doping. Absence of T 2 dependence in the resistivity variation at low T-region serves as an indirect proof of opening up an energy gap at the Fermi surface in one of the spin channels. This is further corroborated by the ab initio electronic structure calculations that suggests that a nearly ferromagnetic half-metallic ground state is stabilized by Sb-p holes produced upon Co doping
Synthesis and structural studies of cobalt(III) complexes of 5-methyl-3-formylpyrazole-N(4)-ethyl/dimethyl thiosemicarbazone and nickel(II) complex of 2-S-methy1-6-methyl-4-formylpyrimidine-N(4)-ethyl thiosemicarbazone
No full textA unique electric discharge-excited solid state x-ray laser
No full textA high-current discharge apparatus with a unique pulsed power supply was successfully constructed to demonstrate intense “anomalous” (exceeding direct charged-particle Bremsstrahlung) x-ray emission in the 1-2 keV range. Anomalous x-ray emission is attributed to ion implantation rather than normal electron Bremsstrahlung x-ray emission. A striking characteristic is that the x-ray energy can be several times the energy of the bombarding ions, suggesting a strong nonlinear mechanism. Such emission was observed during a glow discharge operation in the pressure range 0.1-5.0 torr with a cathode/anode separation of ~4.0 mm. This discharge operates at a voltage of 1-2 kV with a high-pulsed current up to 2 A. The current pulses have “square” time shape with 0.2-2.0 ms duration and a rise time of 0.1 microsecond.Item withdrawn by Mark Zulauf ([email protected]) on 2012-12-12T13:50:34Z
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Ideals in B1(X) and residue class rings of B1(X) modulo an ideal
No full text[EN] This paper explores the duality between ideals of the ring B1(X) of all real valued Baire one functions on a topological space X and typical families of zero sets, called ZB-filters, on X. As a natural outcome of this study, it is observed that B1(X) is a Gelfand ring but non-Noetherian in general. Introducing fixed and free maximal ideals in the context of B1(X), complete descriptions of the fixed maximal ideals of both B1(X) and B1* (X) are obtained. Though free maximal ideals of B1(X) and those of B1* (X) do not show any relationship in general, their counterparts, i.e., the fixed maximal ideals obey natural relations. It is proved here that for a perfectly normal T1 space X, free maximal ideals of B1(X) are determined by a typical class of Baire one functions. In the concluding part of this paper, we study residue class ring of B1(X) modulo an ideal, with special emphasize on real and hyper real maximal ideals of B1(X).Deb Ray, A.; Mondal, A. (2019). Ideals in B1(X) and residue class rings of B1(X) modulo an ideal. Applied General Topology. 20(2):379-393. https://doi.org/10.4995/agt.2019.11417SWORD379393202A. Deb Ray and A. Mondal, On rings of Baire one functions, Applied Gen. Topol. 20, no. 1 (2019), 237-249. https://doi.org/10.4995/agt.2019.10776J. P. Fenecios and E. A. Cabral, On some properties of Baire-1 functions, Int. Journal of Math. Analysis 7, no. 8 (2013), 393-402. https://doi.org/10.12988/ijma.2013.13035L. Gillman and M. Jerison, Rings of Continuous Functions, New York: Van Nostrand Reinhold Co., 1960. https://doi.org/10.1007/978-1-4615-7819-2J. R. Munkres, Topology, Second edition, Pearson Education, Delhi, 2003.L. Vesely, Characterization of Baire-one functions between topological spaces, Acta Universitatis Carolinae. Mathematica et Physica 33, no. 2 (1992), 143-156
Novel Approaches for Offline Data-Driven Evolutionary Multiobjective Optimization
No full textMost multiobjective evolutionary algorithms (MOEAs) assume that analytical functions or simulation models are available while solving a multiobjective optimization problem (MOP). However, in some cases we must start with data and build approximation models known as surrogates that are later used to solve the MOP by an MOEA. These types of problems are called data-driven MOPs. This
thesis is devoted to solving so-called offline data-driven MOPs that are particularly challenging as no new data is available during the optimization process.
The author first presents approaches to utilize the uncertainty in the prediction of Kriging or Gaussian process (GP) surrogates as additional objectives. However, these approaches increase the complexity of the MOP being solved. Hence, the author proposes probabilistic selection approaches that can be embedded in a decomposition-based MOEA without further analytical derivations.
These approaches utilize Monte Carlo sampling and kernel density estimation to calculate the probability of selection criterion of the MOEA and later select individuals based on them. Next, the author proposes an interactive optimization framework that utilizes decision maker’s preferences for uncertainties in addition to preferences for objective values. The framework was further extended to use probabilistic selection approaches for a decomposition-based MOEA and a custom reference vector adaptation technique to consider uncertainty in the solutions during the adaptation process.
Building GPs with all the provided data becomes computationally expensive when the size of the data is large. Hence, the author finally proposes treed GP surrogates for multiobjective optimization (TGP-MO). They can be built with a relatively low computational cost and have a good accuracy exclusively in the regions around the optimal solutions. This thesis provides multiple novel approaches
and detailed experimental studies for solving offline data-driven MOPs with decision support that will enhance real-world problem-solving capabilities.
Keywords: metamodelling, surrogates, Pareto optimality, Kriging, Gaussian processes, evolutionary algorithm, decision making, uncertainty, interactive methods, preference informationunknown accessibilityei tietoa saavutettavuudest
A brief description of the writings, author and period of composition etc. in the family memoir book/ পারিবারিক স্মৃতিলিপি পুস্তকে লেখা, লেখক ও রচনাকাল প্রভৃতির সংক্ষিপ্ত বিবরণ
No full textThe Proverbial Professor Pasupati Sasmal once researched the family memoirs of Jorasanko Thakurbari. Mainly following his research, a brief list of various writings including serial number, title of part of the first line, author, period of composition, page of manuscript etc. is presented here. This is the first part of the given description. The second part of it is as follows: After writing No.105, the list and description (in the second part) of all the remaining writings which are not given serial numbers are also given. Interested Rabindra-inquisitors can know almost all the information at a glance from this list
On rings of Baire one functions
No full textThis paper introduces the ring of all real valued Baire one functions, denoted by B1(X) and also the ring of all real valued bounded Baire one functions, denoted by B∗1(X). Though the resemblance between C(X) and B1(X) is the focal theme of this paper, it is observed that unlike C(X) and C∗(X) (real valued bounded continuous functions), B∗1 (X) is a proper subclass of B1(X) in almost every non-trivial situation. Introducing B1-embedding and B∗1-embedding, several analogous results, especially, an analogue of Urysohn’s extension theorem is established
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