Wszystkie pola: 61.44.-n - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Periodic Series of Peaks in Diffraction Patterns of Aperiodic Structures
Autorzy:: Wolny, J.
Kozakowski, B.
Kuczera, P.
Pytlik, L.
Strzałka, R.
Wnek, A.
Tematy:: 61.44.-n; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1203573.pdf Link otwiera się w nowym oknie
Opis:: Quasicrystals are aperiodic structures with no periodicity both in direct and reciprocal space. The diffraction pattern of quasicrystals consists however of the periodic series of peaks in the scattering vector space. The intensities of the peaks of all series reduced in a proper way build up the so-called envelope function common for the whole pattern. The Fourier transformed envelope gives the average unit cell which is the statistical distribution of atomic positions in physical space. The distributions lifted to high dimensions correspond to atomic surfaces - the basic concept of structural quasicrystals modeling within higher-dimensional approach.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Tiling Spaces of Taylor-Socolar Tilings
Autorzy:: Lee, J.
Tematy:: 61.44.Br
61.44.-n; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1373221.pdf Link otwiera się w nowym oknie
Opis:: The Taylor-Socolar tiling has been introduced as an aperiodic mono-tile tiling. We consider a tiling space which consists of all the tilings that are locally indistinguishable from a Taylor-Socolar tiling and study its structure. It turns out that there is a bijective map between the space of the Taylor-Socolar tilings and a compact Abelian group of a Q-adic space (Q̅) except at a dense set of points of measure 0 in Q̅. From this we can derive that the Taylor-Socolar tilings have quasicrystalline structures. We make a parity tiling from the Taylor-Socolar tiling identifying all the rotated versions of a tile in the Taylor-Socolar tiling by white tiles and all the reflected versions of the tile by gray tiles. It turns out that the Taylor-Socolar tiling is mutually locally derivable from this parity tiling.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Discrete Tomography: Magic Numbers for N-Fold Symmetry
Autorzy:: Huck, C.
Moll, M.
Nilsson, J.
Tematy:: 61.43.-j
61.44.Br; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1372751.pdf Link otwiera się w nowym oknie
Opis:: We consider the problem of distinguishing convex subsets of n-cyclotomic model sets Λ by (discrete parallel) X-rays in prescribed Λ-directions. In this context, a 'magic number' $m_{Λ}$ has the property that any two convex subsets of Λ can be distinguished by their X-rays in any set of $m_{Λ}$ prescribed Λ-directions. Recent calculations suggest that (with one exception in the case n=4) the least possible magic number for n-cyclotomic model sets might just be N+1, where N=lcm(n,2).
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Fusion: a General Framework for Hierarchical Tilings
Autorzy:: Frank, N.
Tematy:: 61.44.Br
02.40.Gh; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1202975.pdf Link otwiera się w nowym oknie
Opis:: One well studied way to construct quasicrystalline tilings is via inflate-and-subdivide (a.k.a. substitution) rules. These produce self-similar tilings-the Penrose, octagonal, and pinwheel tilings are famous examples. We present a different model for generating hierarchical tilings we call "fusion rules". Inflate-and-subdivide rules are a special case of fusion rules, but general fusion rules are more flexible and allow for defects, changes in geometry, and even constrained randomness. A condition that produces homogeneous structures and a method for computing frequency for fusion tiling spaces are discussed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Inhomogeneous Electronic Localization in Icosahedral Quasicrystals
Autorzy:: Prekul, A.
Schegolikhina, N.
Shalaeva, E.
Tematy:: 61.44.Br; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1203241.pdf Link otwiera się w nowym oknie
Opis:: Experimental results indicating that the electronic inhomogeneity may be a fundamental property of icosahedral quasicrystals and their approximants are presented.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Electric-Elastic Field Induced by a Straight Dislocation in One-Dimensional Quasicrystals
Autorzy:: Yang, L.
Gao, Y.
Pan, E.
Waksmanski, N.
Tematy:: 61.44.Br
61.72.Lk
62.20.D-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1202982.pdf Link otwiera się w nowym oknie
Opis:: By using the generalized Stroh formalism, the electric-elastic field induced by a straight dislocation parallel to a periodic axis of a one-dimensional quasicrystal is obtained. The derivation is concise and the solution is in an exact closed form. As an illustration, the electric-elastic fields around a straight dislocation in a one-dimensional hexagonal quasicrystal are studied. Besides the interesting numerical results presented, the generalized Stroh formalism can be applied to more complicated dislocation problems in quasicrystals.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Tsai-Type Quasicrystal and Its Approximant in Au-Al-Tm Alloys
Autorzy:: Tanaka, K.
Tanaka, Y.
Ishimasa, T.
Nakayama, M.
Matsukawa, S.
Deguchi, K.
Sato, N.
Tematy:: 61.66.Dk
61.44.Br; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1373678.pdf Link otwiera się w nowym oknie
Opis:: A P-type icosahedral quasicrystal with a six-dimensional lattice parameter $a_{6D}$ = 7.411 Å is formed as an equilibrium phase in Au-Al-Tm alloy, of which composition was analyzed to be $Au_{46}Al_{38}Tm_{16}$ by electron probe microanalysis. This quasicrystal is observed as a predominant phase in both as-cast and $Au_{49}Al_{34}Tm_{17}$ alloys annealed at 910°C, and as one of main phases in the alloy slowly cooled from 1020°C. A 1/1 approximant, $Au_{48}Al_{38}Tm_{14}$, is also formed near the composition of the quasicrystal. This is a body-centered cubic structure (space group: Im3̅) with a lattice parameter a = 14.458 Å that is an isostructure to the recently reported 1/1 Tsai-type approximant in Au-Al-Yb. This approximant is characterized by disorderly arranged four Au-Al atoms centered at the Tsai-type cluster, presence of atoms at 8c site, and chemical ordering of Au and Al at sites forming a partial triacontahedron.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Mechanical Alloying of $Al_{73}Cu_{11}Cr_{16}$ Alloy from Ion Irradiated Powders
Autorzy:: Medvedeva, E.
Tcherdyntsev, V.
Makhin'ko, F.
Gushchina, N.
Ovchinnikov, V.
Tematy:: 61.44.Br
61.05.cp
81.20.Ev; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1375515.pdf Link otwiera się w nowym oknie
Opis:: $Al_{73}Cu_{11}Cr_{16}$ alloys were prepared by mechanical alloying of the irradiated by $Ar^{+}$ ions elemental powders. Evolution of alloy structure at ball milling, as well as during the further annealing, was investigated using X-ray diffraction and differential scanning calorimetry. It was shown that ball milling leads to the Cu dissolution in Al and Cr and to the formation of $Al_{2}Cu$ intermetallic phase. An increase of the milling duration leads to an increase of the $Al_{2}Cu$ phase content in the samples. Ion irradiation of initial elemental powders results in an increase of their interaction rate at milling. In the case of irradiated powders using as initial materials, a content of $Al_{2}Cu$ phase after milling is higher than in the case of using non-irradiated elemental powders. No effect of irradiation of initial elemental powders on the phase transformation at heating was observed. The annealing results in the decomposition of Al- and Cr-based supersaturated solid solutions. An increase in the $Al_{2}Cu$ phase content at heating was observed only in the samples, which were milled for 4 h. In the samples milled for 14 h, nearly no increase in $Al_{2}Cu$ phase content at heating was observed. Heating up to 500-600°C results in the single-phase decagonal quasicrystalline phase formation for all of the studied samples.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Leaching of Al-Based Polygrain Quasicrystalline and Related Crystalline Surfaces
Autorzy:: Yadav, T.
Mishra, S.
Pandey, S.
Singh, D.
Lowe, M.
Tamura, R.
Mukhopadhyay, N.
Srivastava, O.
McGrath, R.
Sharma, H.
Tematy:: 61.44.Br
81.16.Hc
61.66.Dk
68.37.Hk; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1373698.pdf Link otwiera się w nowym oknie
Opis:: In the present investigation, we have studied leaching on polygrain Al-based quasicrystalline $(i-Al_{63}Cu_{25}Fe_{12})$ as well as crystalline (B2 phase; $Al_{55}Cu_{30}Fe_{15})$ alloy surfaces using a 10 mole NaOH solution. The surface was leached at varying times from 30 min to 8 h and subsequently characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray analysis. Leaching of the samples for 30 min generated a homogeneous layer. However further leaching for 1-8 h yielded nano-size particles on the surface. Spherical microstructure has been observed on the Al-Cu-Fe crystalline surface whereas on the quasicrystalline surface a petal-like microstructure appeared. The implications of the evolution of different microstructures in the context of structure, stability and activity are discussed. The results are compared with the microstructure of leached polygrained samples containing a mixture of different surface orientations.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Phase Transitions in $[N(CH_3)_4]_2ZnCl_4$ and $[N(CH_3)_4]_2CuCl_4$ Crystals Related with the Incommensurate Modulation Existence
Autorzy:: Sveleba, S.
Semotyuk, O.
Katerynchuk, I.
Kunyo, I.
Karpa, I.
Pankivskyi, Yu.
Tematy:: 61.44.Fw
64.70.Rh
78.20.Fm
65.40.Ba; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1812043.pdf Link otwiera się w nowym oknie
Opis:: The continuous phase transitions are observed in the crystals with incommensurate phase. They are transitions of parent-incommensurate phases $(T_i)$; transitions between metastable states; incommensurate-commensurate phases $(T_c)$. It was set that phase transition between parent and incommensurate phase is a continuous second-order phase transition with a critical index β = 0.5. The transition between metastable states is a continuous phase transition through the intermediate temperature region - incommensurate phase. The wave vector changes with the temperature here and wave vectorwe q* = q₁ - q₂ appears, where q₁, q₂ denote commensurate values of incommensurability wave vector of neighboring metastable states. It was shown that the phase transition between incommensurate and commensurate phases is a continuous phase transition.
Dostawca treści:: Biblioteka Nauki

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