scholarly journals Non-closed acoustic cloaking devices enabled by sequential-step linear coordinate transformations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zahra Basiri ◽  
Mohammad Hosein Fakheri ◽  
Ali Abdolali ◽  
Chen Shen
Keyword(s):  
Material Properties ◽  
Free Space ◽  
Incident Radiation ◽  
Coordinate Transformations ◽  
Physical Realization ◽  
Homogeneous Materials ◽  
Meta Atom ◽  
Constitutive Parameters ◽  
Arbitrary Objects ◽  
The Physical Realization

AbstractHitherto acoustic cloaking devices, which conceal objects externally, depend on objects' characteristics. Despite previous works, we design cloaking devices placed adjacent to an arbitrary object and make it invisible without the need to make it enclosed. Applying sequential linear coordinate transformations leads to a non-closed acoustic cloak with homogeneous materials, creating an open invisible region. Firstly, we propose to design a non-closed carpet cloak to conceal objects on a reflecting plane. Numerical simulations verify the cloaking effect, which is completely independent of the geometry and material properties of the hidden object. Moreover, we extend this idea to achieve a directional acoustic cloak with homogeneous materials that can render arbitrary objects in free space invisible to incident radiation. To demonstrate the feasibility of the realization, a non-resonant meta-atom is utilized which dramatically facilitated the physical realization of our design. Due to the simple acoustic constitutive parameters of the presented structures, this work paves the way toward realization of non-closed acoustic devices, which could find applications in airborne sound manipulation and underwater demands.

A FRAMEWORK FOR REPRESENTING AND PRODUCING MOVIES ON QUANTUM COMPUTERS

2011 ◽  
Vol 09 (06) ◽  
pp. 1459-1497 ◽  
Author(s):  
ABDULLAH M. ILIYASU ◽  
PHUC Q. LE ◽  
FANGYAN DONG ◽  
KAORU HIROTA
Keyword(s):  
Quantum Circuits ◽  
Quantum Computers ◽  
Transition Rates ◽  
Projective Measurement ◽  
Physical Realization ◽  
Quantum Devices ◽  
Frame Transition ◽  
Key Frames ◽  
Movie Script ◽  
The Physical Realization

Adopting a generalization of the DiVincenzo criteria for the physical realization of quantum devices, a standalone component each, is proposed to prepare, manipulate, and measure the various content required to represent and produce movies on quantum computers. The quantum CD encodes, prepares, and initializes the broad content or key frames conveying the movie script. The quantum player uses the simple motion operations to manipulate the contents of the key frames in order to interpolate the missing viewing frames required to effectively depict the shots and scenes of the movie. The movie reader combines the projective measurement technique and the ancilla-driven quantum computation to retrieve the classical movie sequence comprising of both the key and viewing frames for each shot. At appropriate frame transition rates, this sequence creates the impression of continuity in order to depict the various movements and actions in the movie. Two well-thought-out examples demonstrate the feasibility of the proposed framework. Concatenated, these components together facilitate the proposed framework for quantum movie representation and production, thus, opening the door towards manipulating quantum circuits aimed at applications for information representation and processing.

The Role of Conceptualization and Design in Product Realization

2011 ◽  
Author(s):  
Mohamed E. M. El-Sayed
Keyword(s):  
Product Development ◽  
Physical Realization ◽  
Development Cycle ◽  
Virtual Realities ◽  
Design And Manufacturing ◽  
Product Development Cycle ◽  
Realization Process ◽  
Product Realization ◽  
The Physical Realization

The term Product realization is usually used to describe the physical realization of a product in the product development cycle. Therefore, the term may or may not include conceptualization and design phases. Considering that product realization means bringing a product to reality, it is important to study the concept of reality to understand the role of conceptualization, design, and manufacturing in product realization. In this paper, the concept of reality is expanded to include the perceptual and virtual realities as integral parts of the product realization process. This paper discusses the three phases of realization and their interactions. It also addresses the key roles of conceptualization, design and manufacturability in the realization process. To illustrate the concepts, presented in the paper, some examples are included.

scholarly journals Backup Hydrogen Maser Steering System for Galileo Precise Timing Facility

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Qinghua Wang ◽  
Pascal Rochat ◽  
Xavier Stehlin
Keyword(s):  
Algorithm Design ◽  
Steering System ◽  
Physical Realization ◽  
Hydrogen Maser ◽  
Short Term ◽  
Outlier Removal ◽  
Precise Timing ◽  
Galileo System ◽  
System Time ◽  
The Physical Realization

Two hydrogen masers (HMs) are used in the Precise Timing Facility to provide the physical realization of Galileo System Time, insuring the extremely high short-term stability required for the navigation functions. In order to allow a smooth switch over between backup and primary HMs, the “backup HM steering algorithm” is developed. This acquires the phase difference measured between two HMs, computes a steering correction, and generates the steering correction to the backup HM via a PicoStepper with a 0.1-picosecond resolution. The algorithm design is based on outlier removal and a proportional-integral filtering controller. To verify the steering operability and the loop performance, the overall backup HM steering system is simulated using real HM-HM measurements, and with simulated anomalies (phase/frequency spikes, jumps, and drift).

MULTILAYER X-RAY MIRRORS, A FIRST STEP TOWARDS THE CUSTOM DESIGN OF NEW MATERIAL PROPERTIES

1985 ◽  
Vol 56 ◽  
Author(s):  
EBERHARD SPILLER
Keyword(s):  
Material Properties ◽  
Atomic Scale ◽  
Amorphous Films ◽  
Thickness Control ◽  
X Ray ◽  
Custom Design ◽  
Boundary Definition ◽  
Homogeneous Materials ◽  
New Material

AbstractSoft x-ray reflectivities up to a factor 104 larger than those of the best homogeneous materials have been obtained with multilayers coatings. Thickness control and boundary definition has been achieved on an atomic scale with amorphous films. We will review design, fabrication, performance and characterization of the coatings and discuss possibilities to extent these methods to the improvement of other material properties.

scholarly journals Phyllotaxis-inspired nanosieves with multiplexed orbital angular momentum

eLight ◽  
2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Zhongwei Jin ◽  
David Janoschka ◽  
Junhong Deng ◽  
Lin Ge ◽  
Pascal Dreher ◽  
...  
Keyword(s):  
Free Space ◽  
High Capacity ◽  
Vortex Generator ◽  
Optical Vortex ◽  
Optical Vortices ◽  
Time Resolved ◽  
Optical Applications ◽  
On Chip ◽  
Pine Cones ◽  
Meta Atom

AbstractNanophotonic platforms such as metasurfaces, achieving arbitrary phase profiles within ultrathin thickness, emerge as miniaturized, ultracompact and kaleidoscopic optical vortex generators. However, it is often required to segment or interleave independent sub-array metasurfaces to multiplex optical vortices in a single nano-device, which in turn affects the device’s compactness and channel capacity. Here, inspired by phyllotaxis patterns in pine cones and sunflowers, we theoretically prove and experimentally report that multiple optical vortices can be produced in a single compact phyllotaxis nanosieve, both in free space and on a chip, where one meta-atom may contribute to many vortices simultaneously. The time-resolved dynamics of on-chip interference wavefronts between multiple plasmonic vortices was revealed by ultrafast time-resolved photoemission electron microscopy. Our nature-inspired optical vortex generator would facilitate various vortex-related optical applications, including structured wavefront shaping, free-space and plasmonic vortices, and high-capacity information metaphotonics.

scholarly journals Extracting elastic constitutive parameters using the VFM within peridynamics

2019 ◽  
Author(s):  
Rolland Delorme ◽  
Patrick Diehl ◽  
Ilyass Tabiai ◽  
Louis Laberge Lebel ◽  
Martin Levesque
Keyword(s):  
Finite Element ◽  
Displacement Field ◽  
Material Properties ◽  
Noise Analysis ◽  
Image Correlation ◽  
Bending Test ◽  
Virtual Fields Method ◽  
Element Analysis ◽  
Constitutive Parameters

This paper implements the Virtual Fields Method within the ordinary state based peridynamic framework to identify material properties. The key equations derived in this approach are based on the principle of virtual works written under the ordinary state based peridynamic formalism for two-dimensional isotropic linear elasticity. In-house codes including a minimization process have also been developed to implement the method. A three-point bending test and two independent virtual fields arbitrarily chosen are used as a case study throughout the paper. The numerical validation of the virtual fields method has been performed on the case study by simulating the displacement field by finite element analysis. This field has been used to extract the elastic material properties and compared them to those used as input in the finite element model, showing the robustness of the approach. Noise analysis and the effect of the missing displacement fields on the specimen’s edges to simulate digital image correlation limitations have also been studied in the numerical part. This work focuses on pre-damage properties to demonstrate the feasibility of the method and provides a new tool for using full-field measurements within peridynamics with a reduced calculation time as there is no need to compute the displacement field. Future works will deal with damage properties which is the main strength of peridynamics.

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