Pattern Of Squares Research Articles

Influence of Flexible and Textile Substrates on Frequency-Selective Surfaces (FSS).

Frequency-selective surfaces (FSS) are two-dimensional geometric structures made of conductive materials that selectively transmit or reflect electromagnetic waves. In this paper, flexible FSS made on textile and film substrates is presented and compared to show the effect of the texture associated with the type of substrate on the shielding properties. Three geometries of patterns of squares in the border, inversion of squares in the border, and circles with a border were used, and the patterns were made by the silver paste screen printing technique. Microscopic analysis (SEM and optical) was performed to determine the degree of substrate coverage and the actual geometry of the pattern. The resistance per square of the obtained patterns was about 50 mΩ/□. The shielding properties of FSS were simulated in Comsol Multiphysics 6.2 software and then measured by the antenna method. Selective textile filters were obtained, depending on the pattern used, with one or two modals with a transmission attenuation of about 15 dB. The paper analyzes the effect of the substrate and the screen printing technique used on the shielding properties of the flexible FSS.

Research on Square and Circular Steel Tubular Columns with Deconstructable Splice Joint Under Cyclic and Axial Testing

Abstract: A steel tubular column is a vertical structural member used in construction to provide essential support. Splice joint is a method of joining two members end to end. When the material being joined cannot be obtained in the desired length, the splice joint is used. For high rise buildings the continuity of columns may break, hence splice connections are provided and columns are installed. Splice joints are deconstructable type joints as the failed parts can be repaired, reassembled or can be even removed when failure occurs. These papers focuses on developing models of square and circular cross sections of steel tubular columns with deconstructable splice joint using a finite element software ANSYS and study their structural behavior. This paper includes a parametric study on the effect of axial loading by varying splice length and thickness, bolt diameter and pattern of square and circular cross sections of steel tubular columns with deconstructable splice joints. Bending moment rotation curves were obtained from cyclic load testing for square and circular cross sections

Photonic controlled metasurface for intelligent antenna beam steering applications including 6G mobile communication systems

This paper presents a novel metasurface antenna whose radiation characteristics can be remotely controlled by optical means using PIN photodiodes. The proposed reconfigurable antenna is implemented using a single radiating element to minimize the size and complexity. The antenna is shown to exhibit a large impedance bandwidth and is capable of radiating energy in a specified direction. The proposed antenna consists of a standard rectangular patch on which is embedded an H-tree shaped fractal slot of order 3. The fractal slot is used to effectively reduce the physical size of the patch by 75 % and to enhance its impedance bandwidth. A metasurface layer is strategically placed above the patch radiator with a narrow air gap between the two. The metasurface layer is a lattice pattern of square framed rhombus ring shaped unit-cells that are interconnected by PIN photodiodes. The metasurface layer essentially acts like a superstrate when exposed to RF/microwave radiation. Placed below the patch antenna is a conductive layer that acts like a reflector to enhance the front-to-back ratio by blocking radiation from the backside of the patch radiator. The patch’s main beam can be precisely controlled by photonically illuminating the metasurface layer. The antenna’s performance was modelled and analyzed with a commercial 3D electromagnetic solver. The antenna was fabricated on a standard dielectric substrate FR4 and has dimensions of 0.778λo × 0.778λo × 0.25λo mm3, where λo is the wavelength of free space centered at 1.35 GHz. Measured results confirm the antenna’s performance. The antenna exhibits a wide fractional band of 55.5 % from 0.978 to 1.73 GHz for reflection-coefficient (S11) better than −10 dB. It has a maximum gain of 9 dBi at 1.35 GHz with a maximum front-to-back ratio (F/B) of 21 dBi. The main beam can be steered in the elevation plane from −24° to +24°. The advantage of the proposed antenna is it does not require any mechanical movements or complicated electronic systems.

Visual attention does not affect the reliability of otoacoustic emission or medial olivocochlear reflex.

This study investigated whether visual attention affects the reliability (i.e., repeatability) of transiently evoked otoacoustic emission (TEOAE) magnitudes or of medial olivocochlear reflex (MOCR) estimates. TEOAEs were measured during three visual attentional conditions: control (subject were seated with eyes closed); passive (subjects looked at a pattern of squares on a computer screen); and active (subjects silently counted an occasionally inverted pattern). To estimate reliability, the whole recording session was repeated the next day. The results showed that visual attention does not significantly affect TEOAE or MOCR magnitudes-or their reliability. It is therefore possible to employ visual stimuli (e.g., watching a silent movie) during TEOAE experiments, a procedure sometimes used during testing to prevent subjects from falling asleep or to keep children still and quiet.

Electrical and Low Frequency Noise Characterization of Graphene Chemical Sensor Devices Having Different Geometries.

Chemiresistive graphene sensors are promising for chemical sensing applications due to their simple device structure, high sensitivity, potential for miniaturization, low-cost, and fast response. In this work, we investigate the effect of (1) ZnO nanoparticle functionalization and (2) engineered defects onto graphene sensing channel on device resistance and low frequency electrical noise. The engineered defects of interest include 2D patterns of squares, stars, and circles and 1D patterns of slots parallel and transverse to the applied electric potential. The goal of this work is to determine which devices are best suited for chemical sensing applications. We find that, relative to pristine graphene devices, nanoparticle functionalization leads to reduced contact resistance but increased sheet resistance. In addition, functionalization lowers 1/f current noise on all but the uniform mesa device and the two devices with graphene strips parallel to carrier transport. The strongest correlations between noise and engineering defects, where normalized noise amplitude as a function of frequency f is described by a model of AN/fγ, are that γ increases with graphene area and contact area but decreases with device total perimeter, including internal features. We did not find evidence of a correlation between the scalar amplitude, AN, and the device channel geometries. In general, for a given device area, the least noise was observed on the least-etched device. These results will lead to an understanding of what features are needed to obtain the optimal device resistance and how to reduce the 1/f noise which will lead to improved sensor performance.

Insights into Water Permeation through hBN Nanocapillaries by Ab Initio Machine Learning Molecular Dynamics Simulations.

Water permeation between stacked layers of hBN sheets forming 2D nanochannels is investigated using large-scale ab initio-quality molecular dynamics simulations. A high-dimensional neural network potential trained on density-functional theory calculations is employed. We simulate water in van der Waals nanocapillaries and study the impact of nanometric confinement on the structure and dynamics of water using both equilibrium and nonequilibrium methods. At an interlayer distance of 10.2 Å confinement induces a first-order phase transition resulting in a well-defined AA-stacked bilayer of hexagonal ice. In contrast, for h < 9 Å, the 2D water monolayer consists of a mixture of different locally ordered patterns of squares, pentagons, and hexagons. We found a significant change in the transport properties of confined water, particularly for monolayer water where the water-solid friction coefficient decreases to half and the diffusion coefficient increases by a factor of 4 as compared to bulk water. Accordingly, the slip-velocity is found to increase under confinement and we found that the overall permeation is dominated by monolayer water adjacent to the hBN membranes at extreme confinements. We conclude that monolayer water in addition to bilayer ice has a major contribution to water transport through 2D nanochannels.

Investigation of pattern-orientation on stress in GaN grown on Si(111) substrate in lateral confinement epitaxy

GaN-on-Si has attracted wide interests for decades due to its advantages in cost effective opto-electronics and power electronics. The essential issue for GaN-on-Si epitaxy is the stress problem. Although many effeorts have beeen deovted, the remaining stress is still large and need to be further reduced. Lateral confinement epitaxy useing sub-millimeter scale patterened Si substrate is one effective approach to solve the stress problem. This work reports the first investigation of how the pattern-orientation influences the stress in GaN grown on Si(111) substrate. Through both experiment and simulation, we find that pattern-orientation play a role in the stress-relief of GaN epitaxy on Si. . For the pattern of square, a lower stress can be obtained when the intersect angle between the square edge and [11¯0]Si approaches 26° and 64°.

Heightened visual attention does not affect inner ear function as measured by otoacoustic emissions.

Previous research has indicated that inner ear function might be modulated by visual attention, although the results have not been totally conclusive. Conceivably, modulation of hearing might occur due to stimulation of the cochlea via descending medial olivocochlear (MOC) neurons. The aim of the present study was to test whether increased visual attention caused corresponding changes in inner ear function, which was measured by the strength of otoacoustic emissions (OAEs) recorded from the ear canal in response to a steady train of clicks. To manipulate attention, we asked subjects to attend to, or ignore, visual stimuli delivered according to an odd-ball paradigm. The subjects were presented with two types of visual stimuli: standard and deviant (20% of all stimuli, randomly presented). During a passive part of the experiment, subjects had to just observe a pattern of squares on a computer screen. In an active condition, the subject’s task was to silently count the occasional inverted (deviant) pattern on the screen. At all times, visual evoked potentials (VEPs) were used to objectively gauge the subject’s state of attention, and OAEs in response to clicks (transiently evoked OAEs, TEOAEs) were used to gauge inner ear function. As a test of descending neural activity, TEOAE levels were evaluated with and without contralateral acoustic stimulation (CAS) by broadband noise, a paradigm known to activate the MOC pathway. Our results showed that the recorded VEPs were, as expected, a good measure of visual attention, but even when attention levels changed there was no corresponding change in TEOAE levels. We conclude that visual attention does not significantly affect inner ear function.

Mask aligner lithography using laser illumination for versatile pattern generation.

Mask aligner lithography is a well-established back-end fabrication process in microlithography. Within the last few years, resolution enhancement techniques have been transferred and adapted from projection lithography to further develop mask aligner lithography, especially concerning achievable resolution. Nonetheless, current technology using a mercury vapor lamp as a light source has reached its limits, e.g. for high-resolution pattering. Within this paper, we present the extension of the existing mask aligner illumination system by replacing the mercury vapor lamp with a solid-state laser. Full-field mask aligner lithography is guaranteed by a rotating diffuser expanding the laser beam and minimizing undesired speckle effects. An additional integrated galvanometer scanner allows a flexible choice of arbitrary angular spectrum distributions of the photomask illumination. We show versatile results like simple binary patterns of squares and triangles, as well as a more complex lateral shape like a blazed grating.

Conductive Improvement of Flexography Printed Silver Pattern by Water Washing

This work demonstrates a simple method to improve the conductivity of flexography printed silver pattern by water washing. The flexography printed silver pattern was firstly dried in an oven under 120 celsius degree, then was placed into the deionized water. Heating post-treatment is used to enhance adhesion between the printed silver layer and the substrate film to prevent the detachment of the silver pattern during water washing. The method is compatible with the PET substrate and printed fine pattern of square and hexagon in room temperature. After 2 hour immersion in water under magnetic stirring, the printed silver pattern of square and hexagon show different conductive improvement of conductivity. The silver pattern of hexagon shape with water washing exhibits much better conductivity than the one wiped by lens wipe paper, as measured by using a multimeter. The confocal laser scanning microscope (CLSM) shows that the morphology of the two shapes of silver pattern was almost no changed, except a little decrease on the thickness of the silver layer.

A unitary or multiple representations of numerical magnitude? - the case of structure in symbolic and non-symbolic quantities.

Currently, there is a controversial debate on whether there is an abstract representation of number magnitude, multiple different ones, or multiple different ones that project onto a unitary representation. The current study aimed at evaluating this issue by means of a magnitude comparison task involving Arabic numbers and structured as well as unstructured non-symbolic patterns of squares. In particular, we were interested whether a specific numerical effect, the unit-decade compatibility effect reflecting decomposed processing of tens and units complying with the place-value structure of the Arabic number system, is affected by input notation. Indeed, a reliable unit-decade compatibility effect was observed in the symbolic-digital notation condition but was absent for unstructured non-symbolic notation. However, for structured non-symbolic notation a – albeit negative – compatibility effect was observed as well. Theses results are hard to reconcile with the notion of an abstract representation of number magnitude. Instead, our data support the existence of multiple representations of numerical magnitude. In addition, the current data indicate that it may not be a question of symbolic vs. non-symbolic notation only but also an issue of the structuring of the input notation. While unstructured non-symbolic quantities seemed to be processed holistically we found evidence suggesting at least partially decomposed processing not only for symbolic Arabic numbers but also for structured non-symbolic quantities.

Morphology of single inhalable particle inside public transit biodiesel fueled bus

In an urban-transit bus, fueled by biodiesel in Toledo, Ohio, single inhalable particle samples in October 2008 were collected and detected by scanning electron microscopy and energy dispersive X-ray spectrometry (SEM/EDS). Particle size analysis found bimodal distribution at 0.2 and 0.5 μm. The particle morphology was characterized by 14 different shape clusters: square, pentagon, hexagon, heptagon, octagon, nonagon, decagon, agglomerate, sphere, triangle, oblong, strip, line or stick, and unknown, by quantitative order. The square particles were common in the samples. Round and triangle particles are more, and pentagon, hexagon, heptagon, octagon, nonagon, decagon, strip, line or sticks are less. Agglomerate particles were found in abundance. The surface of most particles was coarse with a fractal edge that can provide a suitable chemical reaction bed in the polluted atmospheric environment. The three sorts of surface patterns of squares were smooth, semi-smooth, and coarse. The three sorts of square surface patterns represented the morphological characteristics of single inhalable particles in the air inside the bus in Toledo. The size and shape distribution results were compared to those obtained for a bus using ultra low sulfur diesel.

The distribution pattern of squares on the stability of F 4F 6-(BN) n ( n = 10–22) polyhedrons

To gain an insight into the structures and stability of F 4F 6-(BN) n polyhedrons with alternation of B and N atoms, a density functional theory study was performed on all isomers of F 4F 6-(BN) n polyhedrons with n between 10 and 22. The calculation results demonstrate that the lowest energy isomers do not contain B 44 bonds (the bonds shared by two squares) and the energies of those isomers containing B 44 bonds increase with the number of B 44 bonds linearly, indicating that the energetically favored structures of F 4F 6-(BN) n polyhedrons satisfy the isolated square rule and square adjacency penalty rule. The structural analysis reveals that the stability is determined by the pyramidalization of B and N atoms at the square–square fusion. The binding energy is fitted to the numbers of edges and a model is proposed for predicting the relative stability of these B–N polyhedral molecules.

Settlement of Ulva Zoospores on Patterned Fluorinated and PEGylated Monolayer Surfaces

Various designs for coatings that resist the attachment of marine organisms are based on the concept of "ambiguous" surfaces that present both hydrophobic and hydrophilic functionalities as surface domains. In order to facilitate the optimal design of such surfaces, information is needed on the scale of the domains that the settling stages of marine organisms are able to distinguish. Previous experiments showed that Ulva zoospores settle (attach) in high numbers onto fluorinated monolayers compared to PEGylated monolayers. The main aim of the present study was to determine, when zoospores of the green alga Ulva are presented with a choice of fluorinated or PEGylated surfaces, what the minimum dimensions of the two types of surface are that zoospores can detect and consequently settle on. Silicon wafers were chemically modified to produce a pattern of squares containing alternating fluorinated and PEGylated stripes of different widths on either a uniform fluorinated or PEGylated background. Each 1 cm x 1 cm square contained stripes with widths of 500, 200, 100, 50, 20, 5, or 2 microm as well as an unpatterned square with a chemistry opposite that of the background. Spores were selective in choosing where to settle, settling at higher densities on fluorinated stripes compared to PEGylated stripes. However, the magnitude of response, and the consequences for settlement on patterned areas overall, was dependent on both the width of the stripes and the chemistry of the background. The data are discussed in relation to the ability of spores to "choose" favorable sites for settlement and the implications for the development of novel antifouling coatings.

Design for 2D anisotropic photonic crystal with large absolute band gaps by using a genetic algorithm

A 2-state genetic algorithm (GA) approach is used to design a two-dimensional (2D) anisotropic photonic crystal of square lattice with a maximal absolute band gap. The unit cell is devided equally into many small squares, and each filling pattern of squares with two dielectric materials corresponds to a binary number. As a numerical example, the GA gives a 2D Te structure with a relative width of the absolute band gap of about 23%. After a further optimization, a new structure is obtained with a relative width of the absolute band gap of about 28%.

Micropatterning of diacetylenic liposomes on glass surfaces

We report the results on the immobilization of polydiacetylene liposomes on glass substrates obtained by the use of micro-contact printing (μCP) technique. Micro-patterned self-assembled monolayer of 3-aminopropyltriethoxysilane (APS) was formed at contact regions of a polydimethylsiloxane (PDMS) stamp with the clean glass surfaces. Polydiacetylene liposomes were then covalently attached to the APS regions, by amidization between surface amine groups of the pattern and N-hydroxy succinimide moieties of the liposomes. Fluorescence images revealed that the polydiacetylene liposomes were successfully immobilized on glasses forming patterns of squares with a width of 70 μm and dots with diameters of 15 to 50 μm. The results would be potentially useful for developing stable liposome-array sensors based on glasses.

Directed dynamic self-assembly of objects rotating on two parallel fluid interfaces

This paper describes dynamic self-assembly of millimeter-sized objects rotating at two parallel fluid interfaces and interacting with one another hydrodynamically, both in the plane of the interface and between the interfaces. The nature of hydrodynamic interactions between the objects rotating on different interfaces and, consequently, the morphologies of the ordered structures that self-assemble, depend on the sizes and the three-dimensional shapes of the rotating particles. Large particles rotating on one interface (“templates”) can direct the self-assembly of smaller particles (“substrates”) on the other interface. Two examples of directed self-assembly are discussed: (i) selective dimerization of disk spinning on the lower interface under the influence of cylinders rotating on the upper interface, and (ii) assembly of “substrate” rectangles into a pattern of squares that is identical with the pattern formed by the “template” squares. General, qualitative characteristics of the vortex–vortex interactions between objects of complex shapes are discussed.

Continuous attention: rationale and discriminant validation of a test designed for use in psychopharmacology

The continuous attention task (CAT) is a test designed to assess changes in attention due to a variety of factors, for example, drugs. Subjects view a series of 3x3 patterns of squares on a monitor screen, each displayed for 100 msec at intervals of 1.5–2.5 sec, and respond whenever two successive patterns are identical. For such a measure to be validr factors other than attention should be investigated, and shown not to be a factor in performance. Nineteen subjects took part in a study in which information-processing rate and recall of CAT figures was measured. The results showed that a viewing time of 50–60 msec was sufficient for 50% correct recognition of CAT figures, and that recognition with a masked presentation of 100 msec did not differ significantly from an unmaske presentation of 100 msec. Mean recall of CAT figures 2 sec after a 100-msec exposure was 98.2%. These results suggest that performance on the CAT is not limited by either information-processing speed or memory capacity, but is a valid measure of the ability to sustain attention.

Movies from music

A theory of music visualization proposed by Nancy Herman postulates an association between colors and pitches of musical scales. A color raster graphics display is used to generate images of notes, chords, and chord progressions based on this theory. Temporal adjacency of notes or chords is mapped to spatial adjacency of colors, usually in a concentric pattern of squares or circles. By varying certain image parameters, different “brush stroke” effects may be obtained. Illustrations of several computer generated “musical paintings” are included, along with some original paintings for comparison.

Frames, Young tableaux, and Baxter sequences

Publisher Summary This chapter discusses frames, Young tableaux, and Baxter sequences. From a partition of a number, it is possible to construct a diagram that is variously known as a Ferrers' diagram, a Young diagram, a partition diagram, or a frame of a partition. This diagram is drawn as a pattern of squares or boxes in the plane. To create a Young tableau, in a given frame of a partition, one can place a positive integer in each of the squares, subject to the restrictions that these numbers must be nondecreasing along each row of squares and strictly increasing down each column. A standard tableau is a Young tableau in which the numbers 1, 2, …, n each occur exactly once. A Baxter sequence is constructed from a standard tableau and is closely related to other sequences constructed from standard tableaux by Foulkes, under the name line of route, and Schutzenberger.