Phase transformation and Raman spectra in BaTiO3 nanocrystals

2002 ◽  
Vol 718 ◽  
Author(s):  
Jian Yu ◽  
X. J. Meng ◽  
J.L. Sun ◽  
G.S. Wang ◽  
J.H. Chu
Keyword(s):  
Particle Size ◽  
Phase Transformation ◽  
Low Temperature ◽  
Long Range ◽  
Lattice Expansion ◽  
Inversion Symmetry ◽  
Range Interaction ◽  
Cooperative Phenomena ◽  
Long Range Interaction ◽  
Hydrothermal Methods

AbstractIn this paper, size-induced ferroelectricit yweakening, phase transformation, and anomalous lattice expansion are observed in nanocrystalline BaTiO3 (nc-BaTiO3) deriv ed b y low temperature hydrothermal methods, and they are w ellunderstood using the terms of the long-range interaction and its cooperative phenomena altered by particle size in covalen t ionic nanocrystals. In cubic nc-BaTiO3, five modes centerd at 186, 254, 308, 512 and 716 cm-1 are observed Raman active in cubic nanophase, and they are attributed to local rhombohedral distortion breaking inversion-symmetry in cubic nanophase. The254 and 308 cm-1 modes are significantly affected not only by the concentration of hydroxyl defects, but also their particular configuration. And the 806 cm-1 modes found to be closely associated with OH - absorbed on grain boundaries.

scholarly journals Inverse Problem for Ising Connection Matrix with Long-Range Interaction

Mathematics ◽  
2021 ◽  
Vol 9 (14) ◽  
pp. 1624
Author(s):  
Leonid Litinskii ◽  
Boris Kryzhanovsky
Keyword(s):  
Inverse Problem ◽  
Long Range ◽  
Random Number ◽  
Connection Matrix ◽  
Range Interaction ◽  
Connection Matrices ◽  
Ising Systems ◽  
Long Range Interaction ◽  
Matrix Spectrum ◽  
Analytical Expressions

In the present paper, we examine Ising systems on d-dimensional hypercube lattices and solve an inverse problem where we have to determine interaction constants of an Ising connection matrix when we know a spectrum of its eigenvalues. In addition, we define restrictions allowing a random number sequence to be a connection matrix spectrum. We use the previously obtained analytical expressions for the eigenvalues of Ising connection matrices accounting for an arbitrary long-range interaction and supposing periodic boundary conditions.

scholarly journals HiChIP and Hi-C Protocol Optimized for Primary Murine T Cells

2021 ◽  
Vol 4 (3) ◽  
pp. 49
Author(s):  
Tomas Zelenka ◽  
Charalampos Spilianakis
Keyword(s):  
T Cells ◽  
Long Range ◽  
Three Dimensional ◽  
Cell Types ◽  
Range Interaction ◽  
Chromatin Interactions ◽  
Optimized Protocol ◽  
Long Range Interaction ◽  
Chromatin Compactness ◽  
Detailed Protocol

The functional implications of the three-dimensional genome organization are becoming increasingly recognized. The Hi-C and HiChIP research approaches belong among the most popular choices for probing long-range chromatin interactions. A few methodical protocols have been published so far, yet their reproducibility and efficiency may vary. Most importantly, the high frequency of the dangling ends may dramatically affect the number of usable reads mapped to valid interaction pairs. Additionally, more obstacles arise from the chromatin compactness of certain investigated cell types, such as primary T cells, which due to their small and compact nuclei, impede limitations for their use in various genomic approaches. Here we systematically optimized all the major steps of the HiChIP protocol in T cells. As a result, we reduced the number of dangling ends to nearly zero and increased the proportion of long-range interaction pairs. Moreover, using three different mouse genotypes and multiple biological replicates, we demonstrated the high reproducibility of the optimized protocol. Although our primary goal was to optimize HiChIP, we also successfully applied the optimized steps to Hi-C, given their significant protocol overlap. Overall, we describe the rationale behind every optimization step, followed by a detailed protocol for both HiChIP and Hi-C experiments.

scholarly journals Anisotropic long-range interaction investigated with cold atoms

2020 ◽  
Vol 102 (1) ◽  
Author(s):  
Vincent Mancois ◽  
Julien Barré ◽  
Chang Chi Kwong ◽  
Alain Olivetti ◽  
Pascal Viot ◽  
...  
Keyword(s):  
Long Range ◽  
Cold Atoms ◽  
Range Interaction ◽  
Long Range Interaction

Molecular models for recombination and disproportionation of radicals

1983 ◽  
Vol 61 (5) ◽  
pp. 881-887 ◽  
Author(s):  
Sidney W. Benson
Keyword(s):  
Long Range ◽  
Impact Parameter ◽  
Ad Hoc ◽  
Active Surface ◽  
Weakly Bound ◽  
Range Interaction ◽  
Surface Areas ◽  
Long Range Interaction ◽  
Increasing Temperature ◽  
Radical Disproportionation

The modified Gorin model of recombination as a long range interaction of weakly bound radicals, constrained only by steric forces, is rederived to give a collision impact parameter 11% larger than rmax, the separation at the centrifugal maximum. This larger impact parameter resolves some of the earlier difficulties with secondary and tertiary radicals. By imposing a new constraint, that the orientation of the radicals be such as to permit exchange forces to act, a new model is developed in which kr = 1/4 Zr α, where a represents the product of fractions of active surface areas of each radical available for bonding. Excellent agreement is obtained in estimating values of kr.Analysis of disproportionation is made to show that it cannot be described by the tight transition state but must also be governed by similar, long range exchange forces between the bond being attacked and the same "active surface" of the abstracting radical. Using an ad hoc radius for [Formula: see text]equal to 4 Å it is possible to reproduce the data on alkyl radical disproportionation to within ± 10%.The model predicts a small decrease in rate of recombination with increasing temperature. This decrease is more pronounced for bulkier radicals and at higher temperatures (> 900 K).

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