Showing papers on "Zigzag published in 1997"

Zig-Zag and interlaminar equilibria effects in large deflection and postbuckling analysis of multilayered plates

Abstract: Concerning, higher-order shear deformation theories (HSDT) for composite plates, this article presents a numerical investigation on local characteristics (distribution along the plate thickness of in-plane displacement, in-plane normal stress, and transverse shear stress component;) in the large-deflection and postbuckling fields. The von Kdrmdn theory in conjunction with a recent mixed two-dimensional model, elsewhere denoted by the acronym RMZC (Reissner-Mindlin zigzag continuity) is employed. The RAfZC model assumes two independent fields along the plate thickness for displacements and transverse shear stresses, respectively; the displacement model describes the so-called zigzag form for the in-plane components, while the stress field fulfils interlaminar equilibria. Standard displacement formulation is enforced by employing variationalty consistent constitutive equations between stress and displacement unknowns. Finite-element-type approximations are introduced on the plate domain, leading to governin...

Optical waveguide device for wavelength demultiplexing and waveguide crossing

Abstract: A zigzag waveguide device is described that includes at least two optical waveguides converged at a vertex to form a waveguide overlap region. Optical loss in the waveguide overlap region is minimized by including a narrow gap of lower refractive index between the overlap region and each waveguide. This technique is also applied to minimize loss in a region where two optical waveguides cross one another. A mirror or optical filter reflectively couples the two waveguides at the vertex. When the coupling is provided by an optical filter, some range of wavelengths is transmitted out of the zigzag waveguide device, rather than reflected. The transmitted light may be collected by an output waveguide which is wider than the waveguides to minimize loss due to divergence. Light exiting the device may be coupled directly to a photodetector with no intervening optical fiber. In addition, the width of an input waveguide of the zigzag waveguide device is tapered to reduce angular spread of the light in the zigzag device.

Magnetic domains and domain walls in pseudo-single-domain magnetite studied with magnetic force microscopy

Abstract: Magnetic domain and domain wall structures in pseudo-single-domain grains (5-20 gm) of magnetite (Fe304) were studied using magnetic force microscopy. Many of the observed micromagnetic features can be explained by the magnetostatic effects of surfaces and grain edges and interactions within and between walls. Domain walls were frequently subdivided into 1-3 opposite polarity segments separated by Bloch lines, although some walls contained no Bloch lines. Subdivided walls display a characteristic zigzag structure along the easy axis direction, where zigzag angles can be as high as 200-40 o . The zigzagging structure, in addition to wall segmentation, further minimizes the magnetostatic energy of the walls. Bloch lines can be (de)nucleated during wall displacement or after repeated alternating field (AF) demagnetization. Within individual walls, the number of Bloch lines and their pinning locations were found to vary after repeated AF demagnetization demonstrating that walls, like individual grains, can exist in several different local energy minima. The number of Bloch lines appears to be independent of domain state, but frequently the polarity of the wall was coupled with the direction of magnetization in the adjoining domains, such that wall polarity alternates in sign between adjacent walls across an entire grain. Even after the domain magnetization is reversed, the same sense of wall chirality is maintained across the grain producing unique grain chiralities. For one particular grain it was possible to reconfigure a likely three-dimensional (3-D) domain structure. The body and surface structures result primarily from a combined volume magnetostatic interaction between all grain surfaces and magnetocrystalline anisotropy. Finally, commonly observed open-flux features within the interior of grains or along grain edges terminating planar domains are inconsistent with the prediction of edge closure domain formation based on recent 2- D micromagnetic models. Our observations suggest that 3-D micromagnetic models are required to model results even for grains larger than 1 gm.

ATOMIC STRUCTURE OF THE In ON Si(111)(4 × 1) SURFACE

Abstract: The atomic structure of the In on Si(111)(4×1) surface has been determined using direct methods applied to transmission electron diffraction data. It consists of a zigzag chain of In atoms and a region of silicon including a dimer chain. The structure is sufficiently similar to recent models of the Au on Si(111)(5×2) and metal on Si(111)(3×1) structures, that some preliminary generalizations on the linear n×1 and n×2 Si(111) reconstructions can be made.

Solar panel assembly

Abstract: Solar panel assembly (20) comprising a number of rectangular panels (21-26) each carrying solar cells on one of the two main surfaces, said panels being interconnected by mutually parallel hinges (41-45) such that the assembly from a first state, in which the panels are folded zigzag wise into a package, can be brought into a second state in which the package, is unfolded and the panels are situated alongside each other in one plane. In the unfolded state each panel is curved in a direction parallel to the panel edges to which said hinges are attached.

Pattern formation and non-linear phenomena in stretched discotic liquid crystal fibres

Abstract: This paper presents a non-linear numerical and bifurcation analysis of pattern formation phenomena in a discotic nematic liquid crystal confined to annular cylindrical cavities and subjected to extensional deformations. The results are of direct relevance to understanding the industrial melt spinning of mesophase carbon fibres, using discotic nematic liquid crystals precursor materials. Three types of orientation patterns are identified in this study: spatially constant (radial), monotonic (pinwheel), and oscillatory (zigzag). Numerical and closed form analytical results predicting continuous transformations between the radial, pinwheel, zigzag radial orientation modes are presented. The bifurcation analysis provides a direct characterization of the parametric dependence and the transitions between these three basic patterns, and provides a complete understanding of the multistability phenomena that is present in the oscillatory orientation patterns. In general it is found that small fibres of nearly elas...

Temperature Induced Structural Changes in Syndiotactic Polystyrene/cis-Decalin Systems

Abstract: Phase transformations in solutions of syndiotactic polystyrene in cis-decalin has been investigated by differential scanning calorimetry, wide and small angle X-ray scattering, and Fourier transformed infrared spectroscopy. The in-situ performed experiments enabled identification of the different modifications without solvent removal. Quenching a solution leads to formation of the helical ‰-phase. On heating, this phase transforms into the planar zigzag ‚-phase. The transformation of the helical phase (‰) into the planar zigzag (‚) during heating proceeds via a melting-recrystallization process.

Effects of surface topography on formation of defects in smc* devices explained using an alternative chevron description

Abstract: An alternative description of the layer structure of $\mathrm{Sm}{C}^{*}$ devices is used to consider the cause for wide variations in the zigzag defect density in such devices using the same alignment layer material. In this paper, we show how the topography of the surface layer due to imperfect coating techniques and materials promotes the formation of zigzag defects. We show that if the alignment surface slope is greater than the pretilt, high densities of zigzag defects are likely to be present.

Best focus decision method and decision method of exposure requirement using it

Abstract: PROBLEM TO BE SOLVED: To make a best focus position and an optimum exposure amount highly accurate in a short time automatically by deciding a best focus position by calculating information regarding one frequency element of a zigzag line from an image signal obtained by imaging a plurality of photosensitive patterns on an image sensing surface of a photoelectric conversion means SOLUTION: A reticle is arranged inside a surface which is vertical to an optical axis of a projection lens, a pattern having periodicity to one direction is arranged on a surface of the reticle and a plurality of photosensitive patterns M' are formed by transferring the pattern on a wafer W' which is a photosensitive board at different focus positions The plurality of photosensitive patterns M' are imaged in an image sensing surface of a photoelectric conversion means 105 and a best focus position is decided by calculating information regarding one frequency element of a zigzag line constituting an outline of an image of a zigzag opening from an image signal obtained by the photoelectric conversion means 105 Thereby, the best focus position and an optimum exposure amount can be made highly accurate in a short time automatically

The true structure and metal-metal-bonded framework of limoiiio2 determined from total neutron scattering

Abstract: Total neutron diffraction studies show that the layered lithium molybdate, LiMoIIIO2, contains zigzag molybdenum chains within the MoO2 layers. The short distances along the zigzag, dMo-Mo = 2.618 A, are indicative of strong metal−metal bonds. The structure adopted is in agreement with theoretical predictions for a d3 metal system and differs from that previously published. The average structure is best described in the space group = C2/m, with a = 10.543(6) A, b = 2.8626(5) A, c = 10.899(6) A, and β = 153.29(1)°. The utility of determining radial correlation functions from diffraction data as a check on the final structure obtained from Bragg scattering studies of polycrystalline materials is demonstrated.

Design and testing of a large-aperture, high-gain, Brewster 's angle zigzag Nd:glass slab amplifier.

Abstract: At the University of Rochester we have constructed and tested a large-aperture, (1.0 × 6.5 cm), high-gain (8) Brewster’s angle zigzag Nd:glass amplifier with a repetition rate of 2 Hz. This amplifier has a gain uniformity of ±3% and a maximum stress-induced depolarization <2.5%.

Porous flat metal tube heat pipe type heat exchanger

Abstract: PURPOSE: To be able to reduce in cost and weight by zigzag reciprocating between a high temperature heat receiver and a low temperature heat receiver by remolding it in a zigzag shape, and providing the nucleate boiling generator group of operating liquid and condenser group of operating liquid vapor as a heat amount transporting means for mainly vibrating the operating liquid. CONSTITUTION: The porous flat metal tube heat pipe type heat exchanger is bent in a serpentine shape repeatedly reverse rocking motion at each turn on the same flat plane and repeatedly reciprocated in a zigzag motion between a high temperature part H and a low temperature part C. Operating liquid is nucleate boiled in the part H by the principle of a zigzag fine tube heat pipe, and axial vibration is generated in a tunnel by the pressure wave. Thus, heat quantity is effectively transported from the part H toward the part C. That is, efficient heat exchange is executed via a porous flat metal tube heat pipe 1 between the part H and the part C. Thus, the excellent heat exchange with extremely small pressure loss is conducted for a perpendicular convection AR to the zigzag flat surface.

Long-life filter element for e.g. hot oil, fuel and water

Abstract: The filter element comprises a non-woven material containing metal and/or glass fibers. A zigzag folded strip is made from panels or rolled sheet. Individual surfaces are defined by pre-stamping (3, 4, 5, 6).

Theory of local density of states in d-wave superconductors around rough surfaces

Abstract: The spatial dependence of the local density of states (LDOS) of quasiparticles in a dx2−y2-wave superconductor around the rough surfaces is investigated using an extended Hubbard model. The existence of the zero-energy states (ZES) is calculated at the corners of corrugations for nominal [100] surfaces as well as on the ideal [110] surfaces. On the other hand, for flat [100] surface, no ZES are obtained. Even in the case of nominal [110] surfaces, when the intervals of the corners in zigzag structure are larger than the spread of Cooper pairs, the LDOS are not always enhanced at zero energy level. These results explain the wide variety of the spectra obtained in the tunneling experiments of high-Tc superconductors.

Plate filter based on continuous sheet material folded into zigzag configuration

Abstract: The plate filter, in particular, for cleaning the intake air of internal combustion engines incorporates elements produced from continuous sheet material which is folded into a zigzag configuration. The filter comprises adjoining filter regions (1, 2) with different fold depth, with the same fold depth in each particular filter region. The individual filter regions comprise sections produced from separate continuous sheets. The end folds of adjoining filter sections (1, 2) interlock with one another.

Genetic VLSI circuit partitioning with two-dimensional geographic crossover and zigzag mapping

Abstract: A B S T R A C T W e s u g g e s t a n e w g e n e t i c a l g o r i t h m for c i rcu i t r a t i o c u t p a r t i t i o n i n g p r o b l e m . G e n e t i c s p a c e s e a r c h is s t r e n g t h e n e d by t h e g e o g r a p h i c c r o s s o v e r w h i c h e n a b l e s m o r e p o w e r to c r e a t e d i v e r s e s o l u t i o n s . F u r t h e r m o r e , s o l u t i o n s are e m b e d d e d in to t w o d i m e n s i o n a l c h r o m o s o m e s by a n e w e m b e d d i n g ru le to e f f e c t i v e l y u t i l i z e g e n e s ' g e o g r a p h i c a l l inkages . O n e x p e r i m e n t s w i t h t h e pub l i c A C M / S I G D A b e n c h m a r k c i rcu i t s , t h e n e w g e n e t i c a l g o r i t h m s i g n i f i c a n t l y o u t p e r f o r m e d r e c e n t l y p u b l i s h e d s t a t e o f t h e a r t app r o a c h e s .

The zigzag interface shape at the ferroelastic phase transformation

Abstract: The aim of this article is to analyse the shape of an interface between the paraelastic and ferroelastic phases in the static case when the sample is placed in a temperature gradient. It is shown that the resulting shape which is often of a zigzag form follows from the competition between the free energy induced by the gradient, the elastic-strain energy caused by lattice misfits along the interface and the interface surface energy. The evaluation of these energy contributions is unavoidable when their magnitudes are comparable. In the first step we evaluate the change in elastic energy, which is due to the lattice misfit, for an anisotropic medium as the function of growth of the zigzag interface between the phases. In the second step we perform a complete analysis of the zigzag interface in the approximation of an isotropic medium. As the main result of our analysis we show that the formation of a zigzag interface is energetically favourable when the ratio of the product of surface and chemical energies to the square of elastic-strain energy is small. When this condition is not satisfied, the interface remains flat. The analysis shows that depending on the value of a transition between the zigzag interface and the flat interface may exist which is discontinuous. This means that there exists a range of angles characterizing the zigzag shape which is forbidden.

JPEG-like Image Compression using Neural-network-based Block Classification and Adaptive Reordering of Transform Coefficients

Abstract: The research described in this thesis addresses aspects of coding of discrete-cosinetransform (DCT) coefficients, that are present in a variety of transform-based digital-image-compression schemes such as JPEG. Coefficient reordering; that directly affects the symbol statistics for entropy coding, and therefore the effectiveness of entropy coding; is investigated. Adaptive zigzag reordering, a novel versatile technique that achieves efficient reordering by processing variable-size rectangular sub-blocks of coefficients, is developed. Classification of blocks of DCT coefficients using an artificial neural network (ANN) prior to adaptive zigzag reordering is also considered. Some established digital-image-compression techniques are reviewed, and the JPEG standard for the DCT-based method is studied in more detail. An introduction to artificial neural networks is provided. Lossless conversion of blocks of coefficients using adaptive zigzag reordering is investigated, and experimental results are presented. A versatile algorithm, that generates zigzag scan paths for sub-blocks of any dimensions using a binary decision tree, is developed. An implementation of the algorithm based on programmable logic devices (PLDs) is described demonstrating the feasibility of hardware implementations. Coding of the sub-block dimensions, that need to be retained in order to reconstruct a sub-block during decoding, based on the scan-path length is developed. Lossy conversion of blocks of coefficients is also considered, and experimental results are presented. A two-layer feedforward artificial neural network trained using an error-backpropagation algorithm, that determines the sub-block dimensions, is described. Isolated nonzero coefficients of small significance are discarded in some blocks, and therefore smaller sub-blocks are generated.

Multimode interference coupler

Abstract: The passive transparent guide section (4) ensures that amplification of the optical power is selective producing a stronger optical output. The interface can be curved, V-shaped, zigzag or sloping

Charged particle beam transfer device, pattern dividing method, mask, and charged particle beam transfer method

Abstract: PROBLEM TO BE SOLVED: To provide a charged particle beam transfer device, a pattern dividing method, a mask, and a charged particle beam transfer method, wherein a transferred pattern can be lessened in joining error. SOLUTION: When split transfer patterns 3ba, 3bb,... transferred onto a wafer by a charged particle beam are determined, a transfer pattern 3 is split by zigzag splitting lines d2 corresponding to component patterns P11 , P12 ... comprised in it, and the split transfer patterns 3ba, 3bb,... are formed in regions 1aa, 1ab,... on a mask 1. The regions 1aa, 1ab,... of the mask 1 are successively irradiated with a charged particle beam, and the split transfer patterns 3ba, 3bb,... are successively transferred onto the wafer 1, whereby the transfer pattern 3 is formed on the wafer 1.

N-(2-Pyridyl)urea

Abstract: The structure of the title compound, C6H7N3O, is built of layers stacked along the c axis and each layer consists of parallel zigzag ribbons of hydrogen-bonded molecules extended along the ab diagonals. Within the layers, the molecules are plane-to-plane coupled at 3.330 (2) A. The molecular planes from adjacent layers make an angle of 68.0 (1)°.

Avoiding weight-illgrowth: cascade correlation algorithm with local regularization

Abstract: This paper investigates some possible problems of cascade correlation algorithm, one of which is the zigzag output mapping caused by weight-illgrowth of the adding hidden unit. Without doubt, it could lead to deterioration of the generalization, especially for regression problems. To solve this problem, we combine the cascade correlation algorithm with regularization theory. In addition, some new regularization terms are proposed in light of special cascade structure. Simulation has shown that regularization can smooth the zigzag output, so that the generalization is improved, especially for functional approximation.

Occurrence of Both Sinusoidal and Zigzag Supermolecular Structures Associated with Band Textures in a Liquid Crystalline Polymer

Abstract: Band textures are observed in a precipitation film from a presheared poly(1,4-phenylene terephthalamide) solution, a typical lyotropic main-chain polymeric liquid crystal. By polarized optical microscopy (POM) studies and in the same specimen system, both sinusoidal and zigzag supermolecular structures associated with band textures are found, according to the comparison between the experimental micrographs and the theoretical birefringence patterns. As a consequence, the present paper describes how to distinguish these two supermolecular structures merely by POM and demonstrates that both structure models are reasonable. © 1997 by John Wiley & Sons,

Reinforcing system for foam concrete elements

Abstract: The top and bottom bars (3,6) run for the full length of the component. They are joined to each other by connecting bars (8) which run in a zigzag pattern, so as to form a lattice-work structure. The connecting bars are positively joined to the lengthwise ones at their ends. Several such structures can be parallel to each other and joined together via transverse bars. The structures can form groups passing through each other at right angles. The top and bottom bars in a structure, together with the connecting bars between them, can be in a common vertical plane.

On a Binary Zigzag Operation.

Abstract: Ski brake apparatus is provided which includes ski brakes designed to accommodate holding or latching together of the skis when in a stored condition by means of the ski brake structure. In particularly preferred embodiments, pivotally movable brake claws of the brakes at one ski include an opening engageable with the pivot axle for the brake at the other ski. The opening is configured so as to require a pressing together of the bottoms of the skis against their elastic tension to permit insertion and snap-locking of the one ski brake end portion with the pivot axle or pin of the other ski brake to lock the skis together.

Methods and systems for generating alternate and zigzag address scans based on feedback addresses of alternate and zigzag access patterns

Abstract: Methods and systems for generating alternate and zigzag address scans in a reconfigured two-dimensional map under the MPEG-1 and MPEG-2 are provided. In one embodiment, a control signal generator determines the subsequent alternate address based on the present alternate address. In another embodiment, the control signal generator determines the subsequent zigzag address based on the present zigzag address. The subsequent address is generated by incrementing, decrementing, or resetting a pair of up/down counters that are coupled to the inputs of the control signal generator.