New Kind Of Structure Research Articles

Behavior of a structurally dissipating rock-shed: experimental analysis and study of punching effects

This article is about protective structures against rock fall. We present a new concept of rock-shed protection: it consists of a reinforced concrete slab (not protected by any ground embankment) supported by specific supports designed to dissipate the energy of blocks hitting on the edge of the slab. The impact energy is dissipated directly by the actuation of the slab and by the damage concrete and reinforcements or by the buckling of the fuse supports. Unlike traditional rock-shed (covered in soil), this new kind of structure must be designed under dynamic load. Experimental trial runs have been conducted on a one-third scale model of a real structure. It appears that three damaging modes have to be considered: the “concrete compaction”, punching and bending of the slab. In this paper, we focus on the punching effects. In order to propose a simplified design method, we have determined the experimental value of contact time and percussion load. Then, this load is compared with the ultimate punching load of the slab computed by an analytical model (Menétrey) and a standard code (Eurocode 2). It results that whenever the percussion load is higher than the ultimate punching load, the slab has been strongly punched.

Broken hyperbolic structures and affine foliations on surfaces

In this paper, we introduce two new kinds of structures on a non-compact surface: broken hyperbolic structures and broken measured foliations. The space of broken hyperbolic structures contains the Teichmüller space of the surface as a subspace. The space of broken measured foliations is naturally identified with the space of affine foliations of the surface. We describe a topology on the union of the space of broken hyperbolic structures and of the space of broken measured foliations which generalizes Thurston's compactification of Teichmüller space.

Analysis of Photonic Bandgaps in Modified Honeycomb Structures

By introducing an additional air hole into the center of each unit cell of the conventional honeycomb lattice, a new kind of structure that can support air guidance of light with low-order bandgaps is proposed. Numerical investigation indicates that, due to the generation of the lower order bandgaps, larger air-guiding photonic bandgaps (PBGs) than those of triangular structures can be achieved in the new structures. Furthermore, the proposed structures also provide additional freedom in tailoring PBGs.

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Conserved segments 1A and 2B of the intermediate filament dimer: their atomic structures and role in filament assembly.

Intermediate filaments (IFs) are key components of the cytoskeleton in higher eukaryotic cells. The elementary IF 'building block' is an elongated coiled-coil dimer consisting of four consecutive alpha-helical segments. The segments 1A and 2B include highly conserved sequences and are critically involved in IF assembly. Based on the crystal structures of three human vimentin fragments at 1.4-2.3 A resolution (PDB entries 1gk4, 1gk6 and 1gk7), we have established the molecular organization of these two segments. The fragment corresponding to segment 1A forms a single, amphipatic alpha-helix, which is compatible with a coiled-coil geometry. While this segment might yield a coiled coil within an isolated dimer, monomeric 1A helices are likely to play a role in specific dimer-dimer interactions during IF assembly. The 2B segment reveals a double-stranded coiled coil, which unwinds near residue Phe351 to accommodate a 'stutter'. A fragment containing the last seven heptads of 2B interferes heavily with IF assembly and also transforms mature vimentin filaments into a new kind of structure. These results provide the first insight into the architecture and functioning of IFs at the atomic level.

Self similarity and sample length dependence of conductance in quasiperiodic lateral magnetic superlattices

We study the transport of electrons in a Fibonacci magnetic superlattice produced on a two-dimensional electron gas modulated by parallel magnetic field stripes arranged in a Fibonacci sequence. Both the transmission coefficient and conductance exhibit self-similarity and the six-circle property. The presence of extended states yields a finite conductivity at infinite length, that may be detected as an abrupt change in the conductance as the Fermi energy is varied, much as a metal-insulator transition. This is a unique feature of transport in this new kind of structure, arising from its inherent two-dimensional nature.

Properties of a New Kind of Structure: Lattice of Spiral Domains

The properties of a new domain structure, the equilibrium hexagonal lattice of spiral domains in ferrimagnetic films with perpendicular anisotropy were experimentally studied. The intervals of the bias fields and temperatures under which the lattice can be formed are determined. Temperature and field intervals of spiral domain lattice stability are found. The influence of planar fields on the formation and stability of the spiral domain lattice is studied. It is shown that the symmetry of structure formed is determined by a triaxial anisotropy in the film plane.

Synthesis and Photochromic Properties of New Bisthienylethene Derivatives and a Copolymer

Bisthienylethene (BTE)–based photochromic switches exhibit high resistivity, rapid response, and thermal and photo-stability. The synthesis of the BTE derivative shown in the Figure, a new kind of structure for photochromic polymers, is reported. The switching properties—including photo-fatigue resistance—of 1 and its copolymer with methyl methacrylate are detailed.

Reflexivity, community and education for the learning society

In this article it is argued that the idea of a learning society is consonant with developments in the social world conceived as part of the ongoing project of reflexive modernity. This project is characterised by a dynamic process of individualisation which on the one hand results in widening opportunities for self-creation and the construction of democratic, flexible communities, but on the other is associated with new kinds of structures and cultural processes which continue to reproduce inequality whilst failing to counter the tendency to fragmentation. The idea of a learning society is a response to the dilemmas of these ‘new times’. The New Right idea of such a society is reviewed and found wanting; the particular mix of neo-liberal free market ideas and neo-conservative authoritarianism just cannot deliver the flexibility, diversity and scope for reflexivity required at the level of the self or the community. It is then argued that the most appropriate conception of the learning society is that which grasps the nettle of individualism whilst at the same time deploying an understanding of the self as constituted in practices – a model which avoids the conceptual split between the individual and society and captures the duality of persons as individuals and as members of communities. An attempt is then made to outline a curricular and pedagogical strategy appropriate for a democratic version of the learning society. This involves two aspects: first a teaching approach which focuses on the nature of commitment to and participation in reflexive communities and second, one that fosters the kind of self-reflexivity and self-knowledge required for individuals to sustain and develop their self identities in the circumstances of reflexive modernity.

Photoelectric behaviour of lattice-matched GaAs/Al x Ga1- x As quantum well electrodes

The photoelectric properties of the lattice-matched GaAs/AlxGa1-xAs quantum well electrodes and the influence of the electrode structure such as well width, the thickness of outer barrier and the number of period were studied in a nonaqueous electrolyte. A new kind of structure of multiple quantum well electrode with varied well width, possessing the quantum yield three times that of GaAs bulk materials, was designed and fabricated.

Structures Without Rules And Their Implementation In Architecture

Architecture implies regularity for the designer and rule-lessness for the user. This state of things suggests the necessity of a new look into “erraticity”, “irregularity” and “randomness” as elements of the design process. A short examination of these terms makes a revision of the concepts of “order” and “disorder” unavoidable. Such a revision might help in the emergence of new kinds of structures, new concepts of architectural space, and, ultimately, a new approach to architecture.

A time-dependent theory of resonant multiphoton ionization of atoms by short pulses. I. Weak-field results for the two-photon ionization of caesium

We develop a time-dependent theory of resonant multiphoton ionization of an atom by a laser pulse, whose envelope is taken to be a hyperbolic secant in time. The choice of this shape enables us to solve the time-dependent Schrodinger equation analytically for an n-state system, of which up to (n-1) levels can be in resonance with the ground state for par of the time. Using the expressions deduced for excited-state amplitudes, a closed-form representation for continuum amplitudes is derived, from which the photoelectron energy spectrum is calculated. Stark shifts of the bound states explicitly retained in the eigenfunction expansion due to coupling to omitted levels are included perturbatively. The theory is applied in this paper to the two-photon ionization of caesium by weak fields. A new kind of structure is predicted. The results are compared to the spectrum generated by a weak rectangular pulse.

1992 Lemieux Award Lecture Studies related to the penicillin receptor

The relative antibacterial activities of penicillins and cephalosporins are discussed in terms of their differing abilities to complex to and react with penicillin-binding proteins. The insights gained from such an analysis are being used to attempt the design of new kinds of structures targeted to the penicillin receptor. Details of such design, and examples of several new classes of compounds suggested by this work, are described. Some of these compounds exhibit interesting antibacterial activity.

The point-circle vortex

A new kind of structure—the point-circle vortex (PCV)—is investigated. It can preserve its symmetry as it evolves with time. A leap-forging PCV is discussed together with its randomization and collapse.

Crystal chemistry of anion-excess ReO 3-related phases : II. Crystal structure of PrZr 2F 11

A series of rare-earth fluorozirconates LnZr 2F 11 ( Ln = La, Ce, Pr, Nd) was prepared by solid-state reaction of the binary fluorides and indexed on the basis of single-crystal data. PrZr 2F 11 crystal structure was determined ( R = 0.031) from data recorded on a four-circle automatic diffractometer in the Ibam space group, with cell parameters a = 7.716(4) Å, b = 10.006(6)Å, and c = 10.897(6) Å. This structure results from the stacking of alternate single sheets of corner-shared [ZrF 7] 3− monocapped trigonal prisms and of [PrF 8] 5− square antiprisms. PrZr 2F 11 structure is closely related to monoclinic β-ZrF 4 type by ordered anionic insertion transforming [ZrF 7] 3− monocapped trigonal prisms to [ZrF 8] 4− square antiprisms. It also derives from ReO 3 type by a mechanism involving cationic and anionic insertion through a cationic plane net transformation from square 4 4 plane nets to semiregular 3 2.4.3.4. ones. Owing to the presence of LaZr 2F 11 after recrystallization of various fluoride glasses, the description of the cationic subnetwork and of the anionic connections inside this new kind of structure is especially developed in order to give a basis for subsequent investigations of fluoride glass structures.

Lumped parameters and scators

This paper studies a new kind of structure called scator, which has been succesfully used to model concentrations of solutions and fluid flow problems, and has potential for applications in dynamic modelling in economics.

Introduction to general analysis

We give here an extension of the concept of derivative to topological spaces, without any metric or linear assumption. For that a new kind of structure has to be introduced, called structure of Gauss space, whose properties are also interesting in themselves.

Contrast as a Principle of Structure In Vanity Fair

HE STRUCTURE of Vanity Fair is in many ways unlike that of typical Victorian novel, whatever that might be. A general criticism of serial has been that serial form of publication ... has undoubtedly been responsible for much overplotting. The Victorian in general suffers from too heavy a structure.' While this is true of many of novels of Dickens and Collins, it is not true of Vanity Fair. On contrary, Vanity Fair supposedly lacks structure, organization, and plot. It is a novel without a plan;2 like Topsy, [it] just grew.3 And, of course, serial form was to blame: the spasmodic writing of monthly installments prevented good integration.4 However, while it is true that Vanity Fair does not have heavy structure of a Dickens or Collins novel, it is not true that it lacks structure or organization. Just as Thackeray's unity is new-a unity of theme rather than traditional unity of plot involving life of a hero-so is his structure a new kind of structure. In traditional novel, structure depended on continuity of action, on flow of narrative and dramatic action from one climax to next. But with Vanity Fair, principle of structure changes from continuity of action to contrast of characters and actions they perform. Little attention has been paid to influence of serial publication on shape and structure of Victorian novel. Kathleen Tillotson has pointed out that within a single number, bal-