scholarly journals News from the world of modulated intermetallics

2014 ◽  
Vol 70 (a1) ◽  
pp. C167-C167
Author(s):  
Sven Lidin ◽  
Partha Jana ◽  
Carola Müller ◽  
Shuying Piao ◽  
Simeon Ponou
Keyword(s):  
Higher Order ◽  
Ordered Structures ◽  
Modulated Structure ◽  
Formal Modelling ◽  
Modulated Structures ◽  
The World ◽  
Cubic Structure ◽  
Modulation Vector

The number of modulated structures with more than one modulation vector is small, and such structures often pose special problems in solving and refining. This talk will be concentrated on three such cases; The 3+4 dimensionally modulated cubic structure of digenite, the 3+2 dimensionally modulated structure of Cu3In2, the 3+2 dimensionally modulated structure of AuZn3 and the 3+2 dimensionally modulated structure of Se(Sn4)2K10. The three former cases are interesting because they are relatively weakly ordered structures where modelling is straight-forward, but the model itself is less than obvious to understand while the latter case appears highly ordered, but presents formal modelling difficulties. From these and previously known multi dimensional cases it would appear that higher order modulations are very prone to disorder. The image shows the hk0 layer from Se(Sn4)2K10.

X-ray powder diffraction analysis of the incommensurate modulated structure of Bi2Sr2CaCu2O8

1994 ◽  
Vol 9 (1) ◽  
pp. 28-37 ◽  
Author(s):  
D. P. Matheis ◽  
R. L. Snyder
Keyword(s):  
Powder Diffraction ◽  
Structural Parameters ◽  
Lattice Parameter ◽  
Processing Conditions ◽  
Modulated Structure ◽  
X Ray ◽  
Modulated Structures ◽  
Sample Composition ◽  
Modulation Model ◽  
Modulation Vector

X-ray powder diffraction is a convenient tool for monitoring changes in structural parameters due to modifications in sample composition and processing conditions. Due to the complexity of incommensurate modulated structures powder diffraction techniques have not been commonly applied. Programs ALSQ and QRIET have been produced to perform lattice parameter and structure refinements on incommensurate modulated materials with a displacive modulation model. In applying these programs to the Bi2Sr2CaCu2O8 superconductor which has this type of structure, it is shown that a decrease in the lattice parameters and an increase in the modulation vector occurs as the Ca content of the Bi-2212 phase, controlled by the use of the glass ceramic process, increases.

Intergrowth of modulated structures in high Tc Bi-Sr-Ca-Cu-O superconductors

1990 ◽  
Vol 48 (4) ◽  
pp. 76-77
Author(s):  
A.Q. He ◽  
G.W. Qiao ◽  
J. Zhu ◽  
H.Q. Ye
Keyword(s):  
Twin Structure ◽  
Modulated Structure ◽  
High Tc ◽  
One Dimensional ◽  
Lattice Constants ◽  
Superconducting Phases ◽  
Modulated Structures ◽  
Layer Structures

Since the first discovery of high Tc Bi-Sr-Ca-Cu-O superconductor by Maeda et al, many EM works have been done on it. The results show that the superconducting phases have a type of ordered layer structures similar to that in Y-Ba-Cu-O system formulated in Bi2Sr2Can−1CunO2n+4 (n=1,2,3) (simply called 22(n-1) phase) with lattice constants of a=0.358, b=0.382nm but the length of c being different according to the different value of n in the formulate. Unlike the twin structure observed in the Y-Ba-Cu-O system, there is an incommensurate modulated structure in the superconducting phases of Bi system superconductors. Modulated wavelengths of both 1.3 and 2.7 nm have been observed in the 2212 phase. This communication mainly presents the intergrowth of these two kinds of one-dimensional modulated structures in 2212 phase.

Vagueness and the World

2018 ◽  
Author(s):  
Andrew Bacon
Keyword(s):  
Higher Order ◽  
Formal Models ◽  
Logical Space ◽  
The World ◽  
The Way

According to a fairly widespread assumption, there is some definite collection of completely factual or fundamental propositions upon which all truths supervene and which are unaffected by vagueness. This assumption manifests itself in formal models of vagueness as well—for example, the supervaluationist who represents propositions as sets of world-precisification pairs may divide logical space into propositions that only depend on the world-coordinate. This chapter argues that this assumption leads to paradoxes of higher-order vagueness, and, ultimately, should be rejected in favour of a weaker notion of fundamentality or factuality. It suggests an alternative picture in which there is vagueness ‘all the way down’: logical-space can be divided into basic propositions that settle all precise matters, but it is vague where those divisions lie.

scholarly journals “Yay! Yuck!” Toddlers use incongruent emotions to reason about hidden objects

2020 ◽  
Author(s):  
Alexis Sierra Smith-Flores ◽  
Lisa Feigenson
Keyword(s):  
Early Development ◽  
Present Experiment ◽  
Single Agent ◽  
Emotional Responses ◽  
Higher Order ◽  
Single Stimulus ◽  
Developmental Trajectory ◽  
Infants And Toddlers ◽  
The World ◽  
Do So

Infants show impressive sensitivity to others’ emotions from early on, attending to and discriminating different facial emotions, using emotions to decide what to approach or avoid, and recognizing that certain objects and events are likely to produce certain emotional responses. But do infants and toddlers also recognize more abstract features of emotions—features that are not tied to any one emotion in particular? Here we examined the development of the higher order expectation that emotions are more or less mutually exclusive, asking whether young children recognize that people generally do not express two conflicting emotions towards a single stimulus. We first asked whether 26-month old toddlers can use an agent’s incongruent versus congruent emotional responses (“Yay! Yuck!” versus “Yay! Wow!”) to reason about how many objects were hidden in a box. We found that toddlers inferred that incongruent emotions signaled the presence of two numerically distinct objects (Experiment 1). This inference relied on the incongruent emotions being produced by a single agent; when two different agents gave two incongruent emotional responses, toddlers did not assume that two objects must be present (Experiment 2). Finally, we examined the developmental trajectory of this ability. We found that younger, 20-month olds failed to use incongruent emotions to individuate objects (Experiment 3), although they readily used incongruent novel labels to do so (Experiment 4). Our results suggest that by 2-years of age, children use higher order knowledge of emotions to make inferences about the world around them, and that this ability undergoes early development.

scholarly journals The reality of fiction in a literary world: on an excerpt from Stanisław Lem’s Solaris

2020 ◽  
Vol 11 (1) ◽  
pp. 101-107
Author(s):  
Y. Domanskii
Keyword(s):  
Physical Reality ◽  
Literary Text ◽  
Higher Order ◽  
Fictional World ◽  
Actual Reality ◽  
The World ◽  
The Way

Using an excerpt from Stanisław Lem’s Solaris, this article explores the idea that, in a literary text, a fictional world and the world of physical reality may interact to form such a reality that can paradoxically turn out to be more real than what we believe to be the actual reality. It is also shown that the fictional world realized in a literary text may bring the reader to certain conclusions about the world in which he or she lives. Thus, even if literature is in­capable of affecting reality, it can change the way the latter is perceived. A fictional world is not just a reality — it is a reality of a higher order.

scholarly journals Shepard's mirrors or Simon's scissors?

2001 ◽  
Vol 24 (4) ◽  
pp. 704-705 ◽  
Author(s):  
Peter M. Todd ◽  
Gerd Gigerenzer
Keyword(s):  
Higher Order ◽  
Cognitive Mechanisms ◽  
The World

Shepard promotes the important view that evolution constructs cognitive mechanisms that work with internalized aspects of the structure of their environment. But what can this internalization mean? We contrast three views: Shepard's mirrors reflecting the world, Brunswik's lens inferring the world, and Simon's scissors exploiting the world. We argue that Simon's scissors metaphor is more appropriate for higher-order cognitive mechanisms and ask how far it can also be applied to perceptual tasks. [Barlow; Kubovy & Epstein; Shepard]

Zur Schwarzschildschen Lösung in einer einheitlichen Feldtheorie

1964 ◽  
Vol 19 (9) ◽  
pp. 1032-1033
Author(s):  
G. Braunss
Keyword(s):  
Higher Order ◽  
Field Equations ◽  
The World

It is shown that the system of field equations1ϰGmn (Ф) ≡ 1ϰ (Rmn-½gmn R) =2k₀ [gmn(gab Φ,aΦ,b+ F (Φ)) -Φ, m Φ,n] ,in which the gmn are to be considered as functionals of the world field Φ. possesses a nonsingular static centralsymmetrical solution which, assuming F(Φ) ∼ — Φ6, is identical with the SCHWARZ-scHILD-solution up to terms of higher order for large values of r.

Comparison of Ordered and Modulated Structures in InGaP Alloy Semiconductors grown by MOCVD, Chloride-Vpe and LPE Methods

1989 ◽  
Vol 163 ◽  
Author(s):  
O Ueda ◽  
T. Kato ◽  
T. Matsumoto ◽  
M. Hoshino ◽  
M. Takechi ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Liquid Phase ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Ordered Structures ◽  
Modulated Structures ◽  
Alloy Semiconductors ◽  
Photoluminescence Peak ◽  
Metalorganic Chemical

AbstractOrdered and modulated structures in InGaP alloy semiconductors grown on (001) GaAs substrates by metalorganic chemical vapor deposition, chloride-vapor phase epitaxy, and liquid phase epitaxy have been systematically studied by transmission electron microscopy. In InGaP grown by metalorganic chemical vapor deposition at 630°C, strong ordering of CuPt-type has been observed, which is associated with an abnormality in the photoluminescence peak energy. For crystals grown by chloride-vapor phase epitaxy, CuPt-type ordered structures have also been observed. However, the degree of ordering is weaker in the latter case and crystals grown at 576-740°C exhibit normal photoluminescence peak energies. On the other hand, in crystals grown by liquid phase epitaxy, no superstructure spots are found in the electron diffraction patterns and the crystals exhibit normal photoluminescence peak energies. Modulated structures do not depend on the growth method since they are observed in all crystals. From these results, it has been concluded that the ordered structures are not generated under thermal equilibrium conditions but rather by the diffusion and reconstruction of deposited atoms on the growth surface.

X-ray and electron diffraction study of penfieldite: average structure and multiple cells

1995 ◽  
Vol 59 (395) ◽  
pp. 341-347 ◽  
Author(s):  
S. Merlino ◽  
M. Pasero ◽  
N. Perchiazzi ◽  
A. Gianfagna
Keyword(s):  
Electron Diffraction ◽  
Diffraction Study ◽  
Direct Methods ◽  
Electron Diffraction Study ◽  
Hexagonal System ◽  
Modulated Structure ◽  
Structural Relationships ◽  
Modulated Structures ◽  
The Common ◽  
Multiple Cells

AbstractPenfieldite is a lead hydroxychloride mineral with composition Pb2Cl3(OH). It belongs to the hexagonal system, space group P, a = 11.393(3), c = 4.024(1) Å. The 4 Å c parameter corresponds to the basic sub-cell, whereas modulated structures are known with a true c axis 12 times longer. The average crystal structure of penfieldite has been solved with direct methods and refined to Rw = 0.041 for 871 refections collected with Mo-Kα radiation. The chemical and structural relationships between penfeldite and laurelite, Pb2F3(F,Cl,OH), are briefly discussed. An electron diffraction study of penfieldite revealed the occurrence, besides the common modulated structure with C = 12c, of domains with a 15c periodicity. Moreover, a 9c periodicity has been observed in crystals heated at 180°C Penfieldite is quickly destroyed above 200°C.

scholarly journals Transcending the Boundary of Death: Ecclesiastes Through a Nabokovian Lens

2006 ◽  
Vol 14 (5) ◽  
pp. 425-443
Author(s):  
Michael Carasik
Keyword(s):  
Higher Order ◽  
The Sun ◽  
The World ◽  
Entire World ◽  
Pale Fire

AbstractCh. 12 of Ecclesiastes depicts a scene that combines elements of the death of a person with others that describe the death of an entire world. Vladimir Nabokov's novel Invitation to a Beheading ends with a similar scene. Both Nabokov's writings and his biography suggest that he shared Qohelet's view of life "under the sun" as hevel, but his own experience as a creator led him to believe that there is a higher-order reality than our own. The literary technique described here was Nabokov's attempt to show how one might cross the boundary into that higher reality. With a particular focus on Nabokov's novel Pale Fire, I will argue that the parallel to Ecclesiastes suggests that the writer of Eccl. 12:9-14 was also the writer of that entire book, who chose to drop the persona of Qohelet at the end of his book and speak as himself, to burst through the boundaries of death (in 12:7) and offer a view of the world that the Qohelet persona could not perceive.

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