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11.
This supplement contains 222 (angel number) further papers on false or unconfirmed ferroelectric properties in single crystals, ceramics and polymers and only concerns bulk materials. Thus, the number of such papers has reached huge value 727. The papers marked in red have drastically broken the principles of symmetry because they reported the existence of ferroelectricity in crystals without the polar axis. 相似文献
12.
Piotr Kurcok Andrzej Matuszowicz Zbigniew Jedliski Hans R. Kricheldorf Philippe Dubois Robert Jrme 《Macromolecular rapid communications》1995,16(7):513-519
The influence of methyl substituent on the mechanism of the ring-opening polymerization of β-lactones initiated by alkali metal alkoxides is discussed. Attention has been paid to the effect of the substituent position in the monomer molecule on the ring-opening mechanism, the 3,3-dimethyl-2-oxetanone (pivalolactone), 4-methyl-2-oxetanone (β-butyrolactone) and 2-oxetanone (β-propiolactone) being chosen as model monomers. Moreover, it was found unexpectedly that in the case of pivalolactone polymerization, besides open-chain polymers, cyclic oligomers are produced. 相似文献
13.
Zbigniew Jedliski 《Macromolecular Symposia》1992,60(1):235-245
Novel homogeneous initiation systems consisting of organic alkali metal complexes: Me+/Ligand, Me− enable synthesis of “living” tailor made polymers and copolymers promising materials for engineering and biomedical applications. The mechanism of this polymerization has been elucidated. 相似文献
14.
Zbigniew Kisiel Lech Pszczó?kowski Steven B. Charnley 《Journal of Molecular Spectroscopy》2007,241(2):220-229
The rotational spectrum of pyruvic acid has been investigated for the first time in the millimeter-wave region, at 160-314 GHz, and also in supersonic expansion, at 10-17.4 GHz. The analysis of the broadband spectra recorded in this work was carried out with the newly developed AABS software package for Assignment and Analysis of Broadband Spectra, and precise spectroscopic constants are reported for the ground state, the first excited state of the low-frequency skeletal torsional mode ν24, and the first excited state of the methyl torsional mode ν23. Limited results have also been obtained for several higher excited states. The dataset for the ground state currently exceeds 1500 lines and for both the A and E internal rotor sublevels spans the complete range of values of Ka at the mid values of J for the measured transitions. The results were analysed with three freely available computer programs employing different strategies for dealing with internal rotation and a comparative discussion of their merits is made. 相似文献
15.
This paper is devoted to a discussion of the notion of localizability for phonons, i.e., quasiparticles arising from the harmonic vibrations of a system ofn atoms bound to one another by elastic forces. The natural tools for the analysis of localizability are the projection operatorsÊ() acting on the Hilbert space of one-phonon states, where is an arbitrary subset of the set that consists ofn vectors specifying the equilibrium positions ofn atoms. The expectation value ofÊ() is the probability that the phonon belongs to the atoms whose equilibrium positions are characterized by the elements of . For a strongly localizable phonon all of the projection operatorsÊ() commute with one another, whereas in the case of a weakly localizable phonon the operatorsÊ(1) andÊ(2) do not commute when 1 and 2 overlap. With the aid of the Jauch-Piron quantum theory of localization in space, the present paper describes the method of obtainingÊ() and also shows that if in the system ofn atoms there exist normal modes of zero frequency, then the phonon is only weakly localizable. Given the explicit expression forÊ(), one can define the number-of-phonons operator as well as the quasiparticle analogue (given in a companion paper) of the Wigner distribution function. 相似文献
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18.
Zbigniew Romanowski 《Molecular physics》2013,111(13):1339-1348
The h-adaptive, high order finite element method is applied to solve a second order one dimension eigenvalue problem. The finite element formulation for the Lobatto basis is given, for which basis functions of arbitrary order can be constructed. The adaptive algorithm is simple, yet very efficient and straightforward to implement. The algorithm is based on the observation that the expansion coefficients of Lobatto basis functions decay rapidly. It allows evaluating the smallest eigenvalues simultaneously with the comparable accuracy for all eigenvalues. The presented algorithm is applied to solve the radial Schrödinger equation with the Coulomb and the Woods–Saxon potentials. For both potentials the convergence rate is presented. After seven adaptive iterations nine-digit accuracy was obtained. 相似文献
19.
Stachurski ZH 《Physical review letters》2003,90(15):155502
It is proposed that two ideal amorphous structures, type I and type II, based on maximally random jammed packing of spheres of equal size, form a distinct class of ideal amorphous solids. The ideal amorphous structures contain wide variations in local density, limited by the condition of solidity. Four distinct characteristics, based on statistical geometry and topology, are shown to define this class. Voronoi tessellations carried out on simulated cells of random packed spheres and amorphous polymers give a broad distribution of individual volumes, skewed, with a tail at the high volume end. 相似文献
20.
Piotr Kurcok Andrzej Matuszowicz Zbigniew Jedliski 《Macromolecular rapid communications》1995,16(3):201-206
The anionic polymerization of 2-oxetanone and 4-methyl-2-oxetanone initiated with the potassium hydride/18-crown-6 complex was investigated. The α-proton abstraction of the monomer was found to proceed at the initiation step of this polymerization. The salt of the unsaturated carboxylic acid formed initiates further propagation, leading to functionalized polyesters with unsaturated, dead end-groups. 相似文献