A 1-Bit Bidirectional Reconfigurable Transmit-Reflect-Array Using a Single-Layer Slot Element With PIN Diodes

This paper presents a practical demonstration for the design and development of a switchable planar reflectarray using PIN diodes in the X-band frequency range. Waveguide scattering parameter measurements for the unit cells and far-field measurements of the periodic reflectarrays have been carried out to verify the predicted results. Reflectarray unit cell measurements demonstrated a frequency tunability of 0.36 GHz with a dynamic phase range of 226°. On the other hand, the designed 6 × 6 periodic reflectarray has been shown to achieve beam switching from +6° to −6° with different switching states of PIN diodes. This type of beam switching can be used in satellite communication for specific region coverage.

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Control Radiation Pattern for Half Width Microstrip Leaky Wave Antenna by Using PIN Diodes

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v8i5.pp2959-2966 ◽

2018 ◽

Vol 8 (5) ◽

pp. 2959

Author(s):

Mowafak khadom Mohsen ◽

M.S.M. Isa ◽

Z. Zakaria ◽

A.A.M. Isa ◽

M. K. Abdulhameed ◽

...

Keyword(s):

Radiation Pattern ◽

Impedance Matching ◽

Control Cell ◽

Single Layer ◽

Free Edge ◽

Half Width ◽

Main Beam ◽

Leaky Wave ◽

Pin Diodes ◽

Operation Frequency

<p class="Default">In this paper, a novel design for single-layer half width microstrip leakywave antenna (HW-MLWA) is demonstrated. This model can be digitally control its radiation pattern at operation frequency and uses only two values of the bias voltage, with better impedance matching and insignificant gain variation. The scanning and controlling the radiation pattern of leaky-wave antennas (LWA) in steps at an operation frequency, by using switches PIN diodes, is investigated and a novel HW-MLWA is introduced. A control cell reconfigurable, that can be switched between two states, is the basic element of the antenna. The periodic LWA is molded by identical control cells where as a control radiation pattern is developed by combining numerous reconfigurable control cells. A gap capacitor is independently connected or disconnected in every unit cell by using a PIN diode switch to achieve fixedfrequency control radiation pattern scanning. The profile reactance at the free edge of (HW-MLWA) and thus the main lobe direction is altered by changing the states of the control cell. The antenna presented in this paper, can scan main beam between 18o to 44o at fixed frequency of 4.2 GHz with measured peak gain of 12.29 dBi.</p>

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Crystalline order to a resolution of 4.7 A in the sheath of Methanospirilium hungatii: A cross-beta structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111185 ◽

1984 ◽

Vol 42 ◽

pp. 214-215

Author(s):

Murray Stewart ◽

T.J. Beveridge ◽

D. Sprott

Keyword(s):

Cell Wall ◽

Single Layer ◽

Uranyl Acetate ◽

Optical Diffraction ◽

Tube Axis ◽

Basic Subunit ◽

Beta Structure ◽

Diffraction Patterns ◽

Protein Treatment ◽

General Appearance

The archaebacterium Methanospirillum hungatii has a sheath as part of its cell wall which is composed mainly of protein. Treatment with dithiothreitol or NaOH released the intact sheaths and electron micrographs of this material negatively stained with uranyl acetate showed flattened hollow tubes, about 0.5 μm diameter and several microns long, in which the patterns from the top and bottom were superimposed. Single layers, derived from broken tubes, were also seen and were more simply analysed. Figure 1 shows the general appearance of a single layer. There was a faint axial periodicity at 28.5 A, which was stronger at irregular multiples of 28.5 A (3 and 4 times were most common), and fine striations were also seen at about 3° to the tube axis. Low angle electron diffraction patterns (not shown) and optical diffraction patterns (Fig. 2) from these layers showed a complex meridian (as a result of the irregular nature of the repeat along the tube axis) which showed a clear maximum at 28.5 A, consistent with the basic subunit spacing.

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Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159692 ◽

1990 ◽

Vol 48 (3) ◽

pp. 430-431

Author(s):

Maria Anna Pabst

Keyword(s):

Apis Mellifera ◽

Distal Part ◽

Cell Layer ◽

Single Layer ◽

Photoreceptor Cells ◽

Distal Segment ◽

Compound Eyes ◽

Thin Sections ◽

Ultrastructural Studies ◽

Adult Worker

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

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Characterization of a monolayer graphitic structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171535 ◽

1994 ◽

Vol 52 ◽

pp. 760-761

Author(s):

X. Lin ◽

X. K. Wang ◽

V. P. Dravid ◽

J. B. Ketterson ◽

R. P. H. Chang

Keyword(s):

Three Dimensional ◽

Single Layer ◽

Synthesis Process ◽

Graphitic Structure ◽

Positive Gaussian Curvature ◽

Graphitic Sheet ◽

Structural And Electronic Properties ◽

New Material ◽

Hexagonal Network

For small curvatures of a graphitic sheet, carbon atoms can maintain their preferred sp2 bonding while allowing the sheet to have various three-dimensional geometries, which may have exotic structural and electronic properties. In addition the fivefold rings will lead to a positive Gaussian curvature in the hexagonal network, and the sevenfold rings cause a negative one. By combining these sevenfold and fivefold rings with sixfold rings, it is possible to construct complicated carbon sp2 networks. Because it is much easier to introduce pentagons and heptagons into the single-layer hexagonal network than into the multilayer network, the complicated morphologies would be more common in the single-layer graphite structures. In this contribution, we report the observation and characterization of a new material of monolayer graphitic structure by electron diffraction, HREM, EELS.The synthesis process used in this study is reported early. We utilized a composite anode of graphite and copper for arc evaporation in helium.

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The Continuous Single-Layer Anastomosis in the Gastrointestinal Tract

Swiss Surgery ◽

10.1024/1023-9332.9.3.114 ◽

2003 ◽

Vol 9 (3) ◽

pp. 114-120 ◽

Cited By ~ 1

Author(s):

Steinke ◽

Leippold ◽

Schweizer

Keyword(s):

Gastrointestinal Tract ◽

Single Layer

Über die Frage der besten oder "richtigen" Technik bei gastrointestinalen Anastomosen wird seit je diskutiert. Die Ansprüche an eine gute Anastomosentechnik sind: Gute Durchblutung, Wasserdichtigkeit, Spannungsfreiheit, Sicherheit, leichte Durchführbarkeit, wenig Unruhe und Verschmutzung im Operationsgebiet und geringe Kosten. Die Operationstechnik der extramukösen, fortlaufenden Anastomosentechnik im Gastrointestinaltrakt wird in Wort und Bild erläutert. Anhand einer Pilotstudie, einer randomisierten Vergleichsstudie, einer Schweizer Multizenterstudie und schliesslich einer 5-jährigen Qualitätskontrollstudie wird gezeigt, dass diese "Schweizer"-Technik allen Anforderungen zur Durchführung einer "idealen" Anastomose gerecht wird und an fast allen intestinalen Lokalisationen verwendet werden kann.

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Technical textiles for protection against Arc-flash fire: Savesplash®

WEENTECH Proceedings in Energy ◽

10.32438/wpe.0602100 ◽

2020 ◽

pp. 67-78

Author(s):

Nandan Kumar ◽

Sainath Shrikant Pawaskar

Keyword(s):

Attenuation Factor ◽

Threshold Energy ◽

Single Layer ◽

Weather Conditions ◽

Electric Arc ◽

Risk Category ◽

Technical Textiles ◽

Flash Fire ◽

Level 3 ◽

Arc Flash

Flash fire caused by electric arc is different than that caused by flammable liquids/fumes or combustible dusts. A suitable protective clothing for protection against electric arc-flash must be designed as per Indian weather conditions. Currently available garments are manufactured using two or three layers of woven/nonwoven combinations to achieve higher Hazard Risk Category (HRC) rating (level 3 and above). However, they are heavy and not comfortable to the end users. Savesplash® is a single layer inherent flame-retardant knitted fabric. Its arc rating was determined using ASTM standards. It achieved arc thermal performance value (ATPV) of 41 cal/cm2, breakopen threshold energy (E_BT) of 42 cal/cm2 and heat attenuation factor (HAF) of 94% when tested as per ASTM F1959/F1959M-14 which translated into an arc rating of 41 cal/cm2. This is equivalent to HRC level 4 ratings as per National Fire Protection Association’s NFPA 70E standard (USA). Further, cut and sewn gloves (HM-100) developed using Savesplash® fabric reinforced with leather on palm area achieved ATPV of 63 cal/cm2 and HAF of 94.5% when tested as per ASTM F2675/F2675M-13.

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Discrete element method to model cracking for two layer systems

TAPPI Journal ◽

10.32964/tj18.2.101 ◽

2019 ◽

Vol 18 (2) ◽

pp. 101-108

Author(s):

Daniel Varney ◽

Douglas Bousfield

Keyword(s):

Discrete Element Method ◽

Flexural Modulus ◽

Single Layer ◽

Discrete Element ◽

Flexural Stress ◽

Layer System ◽

Three Point Bending ◽

Moving Force ◽

Coating Layers ◽

Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

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