scholarly journals Controlling asymmetric transmission phase in planar chiral metasurfaces

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ranran Zhang ◽  
Qiuling Zhao ◽  
Xia Wang ◽  
Kai Ming Lau ◽  
Tsz Kit Yung ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Oscillatory Behavior ◽  
Tuning Parameter ◽  
Sapphire Crystal ◽  
Asymmetric Transmission ◽  
Light Manipulation ◽  
Chiral Structures ◽  
Potential Applications ◽  
Using Data ◽  
Transmission Phase

Abstract Metasurfaces with ultrathin artificial structures have attracted much attention because of their unprecedented capability in light manipulations. The recent development of metasurfaces with controllable responses opens up new opportunities in various applications. Moreover, metasurfaces composed of twisted chiral structures can generate asymmetric responses for opposite incidence, leading to more degrees of freedom in wave detections and controls. However, most past studies had focused on the amplitude responses, not to mention using bi-directional phase responses, in the characterization and light manipulation of chiral metasurfaces. Here, we report a birefringent interference approach to achieve a controllable asymmetric bi-directional transmission phase from planar chiral metasurface by tuning the orientation of the metasurface with respect to the optical axis of an add-on birefringent substrate. To demonstrate our approach, we fabricate planar Au sawtooth nanoarray metasurface and measure the asymmetric transmission phase of the metasurface placed on a birefringent sapphire crystal slab. The Au sawtooth metasurface-sapphire system exhibits large oscillatory behavior for the asymmetric transmission phase with the tuning parameter. We confirm our experimental results by Jones matrix calculations using data obtained from full-wave simulations for the metasurface. Our approach in the characterization and light manipulation of metasurfaces with controllable responses is simple and nondestructive, enabling new functionalities and potential applications in optical communication, imaging, and remote sensing.

scholarly journals Toward Inkjet Additive Manufacturing Directly Onto Human Anatomy

2017 ◽  
Author(s):  
Reed A. Johnson ◽  
John J. O’Neill ◽  
Rodney L. Dockter ◽  
Timothy M. Kowalewski
Keyword(s):  
Degrees Of Freedom ◽  
Cell Structure ◽  
Case Depth ◽  
Human Anatomy ◽  
Wound Treatment ◽  
Burn Wound ◽  
Organ Regeneration ◽  
Potential Applications ◽  
Contact Free ◽  
Three Degrees Of Freedom

Bioprinting technology has been rapidly increasing in popularity in the field of tissue engineering. Potential applications include tissue or organ regeneration, creation of biometric multi-layered skin tissue, and burn wound treatment [1]. Recent work has shown that living cells can be successfully applied using inkjet heads without damaging the cells [2]. Electrostatically driven inkjet systems have the benefit of not generating significant heat and therefore do not damage the cell structure. Inkjets have the additional benefit of depositing small droplets with micrometer resolution and therefore can be used to build up tissue like structures. Previous attempts at tracking and drawing on a hand include either direct contact with the hand [3] or tracking the hand only in two degrees of freedom [4]. In this work we present an approach to track a hand with three degrees of freedom and accurately apply a substance contact free to the hand in a desired pattern using a bioprinting compatible inkjet. The third degree of freedom, in this case depth from the hand surface, provides improved control over the distance between the inkjet head and object, thus increasing deposition accuracy.

Generalized Abbe Principle: Position Error Propagation in Machine Elements

1996 ◽  
Author(s):  
Joseph Pegna
Keyword(s):  
Error Propagation ◽  
Degrees Of Freedom ◽  
Rigid Bodies ◽  
Statistical Characterization ◽  
Physical Limit ◽  
Potential Applications ◽  
Machine Elements ◽  
Tolerance Verification ◽  
Precision Machines

Abstract In the quest for ever finer levels of technology integration, mechanical linkages reach their precision limits at about 5micrometers per meter of workspace. Beyond this physical limit, all six dimensional degrees of freedom need to be precisely ascertained to account for mechanical imperfections. This paper substantiates Wu’s vision of “precision machines without precision machinery.” A formulation and statistical characterization of position and orientation error propagation in rigid bodies are presented for two extreme models of measurement. It is shown that error distribution is uniquely dependent upon the design of the measurement plan. The theoretical foundations presented were evolved in the course of designing precision machinery. Other potential applications include: fixture design, metrology, and geometric tolerance verification.

scholarly journals Replicator degrees of freedom allow publication of misleading failures to replicate

2019 ◽  
Vol 116 (51) ◽  
pp. 25535-25545 ◽  
Author(s):  
Christopher J. Bryan ◽  
David S. Yeager ◽  
Joseph M. O’Brien
Keyword(s):  
Data Analysis ◽  
Experimental Design ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Current Practice ◽  
False Negative ◽  
Ongoing Debate ◽  
Key Dimensions ◽  
Using Data

In recent years, the field of psychology has begun to conduct replication tests on a large scale. Here, we show that “replicator degrees of freedom” make it far too easy to obtain and publish false-negative replication results, even while appearing to adhere to strict methodological standards. Specifically, using data from an ongoing debate, we show that commonly exercised flexibility at the experimental design and data analysis stages of replication testing can make it appear that a finding was not replicated when, in fact, it was. The debate that we focus on is representative, on key dimensions, of a large number of other replication tests in psychology that have been published in recent years, suggesting that the lessons of this analysis may be far reaching. The problems with current practice in replication science that we uncover here are particularly worrisome because they are not adequately addressed by the field’s standard remedies, including preregistration. Implications for how the field could develop more effective methodological standards for replication are discussed.

scholarly journals CHARGED PION PHOTOPRODUCTION FROM HYDROGEN AND DEUTERIUM AT JEFFERSON LAB

2003 ◽  
Vol 18 (02n06) ◽  
pp. 215-224
Author(s):  
◽  
HAIYAN GAO
Keyword(s):  
Cross Sections ◽  
Degrees Of Freedom ◽  
Charged Pion ◽  
Center Of Mass ◽  
Oscillatory Behavior ◽  
Color Transparency ◽  
Jefferson Lab ◽  
Glauber Theory ◽  
Nuclear Dependence ◽  
Exclusive Processes

The γn → π-p and γp → π+n reactions are essential probes of the transition from meson-nucleon degrees of freedom to quark-gluon degrees of feedom in exclusive processes. The cross sections of these processes are also, advantageous, for the investigation of oscillatory behavior around the quark counting prediction, since they decrease relatively slower with energy compared with other photon-induced processes. Moreover, these photoreactions in nuclei can probe the QCD nuclear filtering and color transparency effects. In this talk, I discuss the preliminary results on the γp → π+n and γn → π-p processes at a center-of-mass angle of 90° from Jefferson Lab experiment E94-104. I also discuss a new experiment in which singles γp → π+n measurement from hydrogen, and coincidence γn → π-p measurements at the quasifree kinematics from deuterium and 12 C for photon energies between 2.25 GeV to 5.8 GeV in fine steps at a center-of-mass angle of 90° are planned. The proposed measurement will allow a detailed investigation of the oscillatory scaling behavior in photopion production processes and the study of the nuclear dependence of rather mysterious oscillations with energy that previous experiments have indicated. The various nuclear and perturbative QCD approaches, ranging from Glauber theory, to quark-counting, to Sudakov-corrected independent scattering, make dramatically different predictions for the experimental outcomes.

Novel Deployable Mechanisms With Decoupled Degrees-of-Freedom

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Shengnan Lu ◽  
Dimiter Zlatanov ◽  
Xilun Ding ◽  
Rezia Molfino ◽  
Matteo Zoppi
Keyword(s):  
Degrees Of Freedom ◽  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Three Dimensions ◽  
Potential Applications ◽  
Magnification Ratio ◽  
The Relationship ◽  
Kinematic Properties ◽  
Kinematic Simulations

A novel family of deployable mechanisms (DMs) is presented. Unlike most such devices, which have one degree-of-freedom (DOF), the proposed DM can be deployed and compacted independently in two or three directions. This widens the range of its potential applications, including flexible industrial fixtures and deployable tents. The mechanism's basic deployable unit (DU) is assembled by combining a scissor linkage and a Sarrus linkage. The kinematic properties of these two components and of the combined unit are analyzed. The conditions under which the unit can be maximally compacted and deployed are determined through singularity analysis. New 2DOF DMs are obtained by linking the DUs: each mechanism's shape can be modified in two directions. The relationship between the degree of overconstraint and the number of DUs is derived. The magnification ratio is calculated as a function of link thickness and the number of DUs. The idea of deployment in independent directions is then extended to three dimensions with a family of 3DOF mechanisms. Finally, kinematic simulations are performed to validate the proposed designs and analyses.

scholarly journals THREE SIMPLE HEURISTICS MATHEMATICAL PROOFS ON LASSO THEORY

2020 ◽  
Vol 38 (2) ◽  
pp. 243
Author(s):  
Carlos José dos REIS ◽  
Laerte Dias de CARVALHO ◽  
Lucas Monteiro CHAVES ◽  
Devanil Jaques de SOUZA
Keyword(s):  
Unbiased Estimator ◽  
Degrees Of Freedom ◽  
Piecewise Linear ◽  
Tuning Parameter ◽  
Geometrical Approach ◽  
Mathematical Proofs ◽  
Selection Operator ◽  
Simple Heuristics

Three relevant facts about the least absolute shrinkage and selection operator (Lasso) are studied: The estimatives follows piecewise linear curves in relation to tuning parameter, the number of nonzero selected covariates is an unbiased estimator of its degrees of freedom and when the number of covariates p is greater than the numbers of observations n at most n covariates are selected. These results are well known and described in the literature, but with no simple demonstrations. We present, based on a geometrical approach, simple and intuitive heuristics proofs for these results.

scholarly journals Modeling and Experimental Validation of the Chaotic Behavior of a Robot Whip

2019 ◽  
Vol 36 (3) ◽  
pp. 373-394
Author(s):  
Thomas M. Kwok ◽  
Zheng Li ◽  
Ruxu Du ◽  
Guanrong Chen
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Chaotic Behavior ◽  
Experimental Testing ◽  
Modern Technology ◽  
Soft Body ◽  
Revolute Joints ◽  
Air Damping ◽  
Rigid Body Model ◽  
Potential Applications

ABSTRACTAlthough the whip is a common tool that has been used for thousands of years, there have been very few studies on its dynamic behavior. With the advance of modern technology, designing and building soft- body robot whips has become feasible. This paper presents a study on the modeling and experimental testing of a robot whip. The robot whip is modeled using a Pseudo-Rigid-Body Model (PRBM). The PRBM consists of a number of pseudo-rigid-links and pseudo-revolute-joints just like a multi-linkage pendulum. Because of its large number of degrees of freedom (DOF) and inherited underactuation, the robot whip exhibits prominent transient chaotic behavior. In particular, depending on the initial driving force, the chaos may start sooner or later, but will die down because of the gravity and air damping. The dynamic model is validated by experiments. It is interesting to note that with the same amount of force, the robot whip can generate a velocity more than 3 times and an acceleration up to 43 times faster than that of its rigid counterpart. This gives the robot whip some potential applications, such as whipping, wrapping and grabbing. This study also helps to develop other soft-body robots that involve nonlinear dynamics.

scholarly journals Programmable active kirigami metasheets with more freedom of actuation

2019 ◽  
Vol 116 (52) ◽  
pp. 26407-26413 ◽  
Author(s):  
Yichao Tang ◽  
Yanbin Li ◽  
Yaoye Hong ◽  
Shu Yang ◽  
Jie Yin
Keyword(s):  
Mechanical Properties ◽  
Degrees Of Freedom ◽  
Universal Design ◽  
Environmental Temperature ◽  
Mechanical Forces ◽  
Stimuli Responsive ◽  
Responsive Materials ◽  
Promising Strategy ◽  
Unit Cells ◽  
Potential Applications

Kirigami (cutting and/or folding) offers a promising strategy to reconfigure metamaterials. Conventionally, kirigami metamaterials are often composed of passive cut unit cells to be reconfigured under mechanical forces. The constituent stimuli-responsive materials in active kirigami metamaterials instead will enable potential mechanical properties and functionality, arising from the active control of cut unit cells. However, the planar features of hinges in conventional kirigami structures significantly constrain the degrees of freedom (DOFs) in both deformation and actuation of the cut units. To release both constraints, here, we demonstrate a universal design of implementing folds to reconstruct sole-cuts–based metamaterials. We show that the supplemented folds not only enrich the structural reconfiguration beyond sole cuts but also enable more DOFs in actuating the kirigami metasheets into 3 dimensions (3D) in response to environmental temperature. Utilizing the multi-DOF in deformation of unit cells, we demonstrate that planar metasheets with the same cut design can self-fold into programmable 3D kirigami metastructures with distinct mechanical properties. Last, we demonstrate potential applications of programmable kirigami machines and easy-turning soft robots.

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