scholarly journals Generation and characterization of complex vector modes with digital micromirror devices: a tutorial

2021 ◽  
Author(s):  
XiaoBo Hu ◽  
Carmelo Rosales-Guzmán
Keyword(s):  
Degrees Of Freedom ◽  
Complex Vector ◽  
Arbitrary Vector ◽  
Polarization Distribution ◽  
Research Fields ◽  
Great Relevance ◽  
Quantum Entangled States ◽  
Digital Micromirror Devices ◽  
Novel Applications

Abstract Complex vector light modes with a spatial variant polarization distribution have become topical of late, enabling the development of novel applications in numerous research fields. Key to this is the remarkable similarities they hold with quantum entangled states, which arises from the non-separability between the spatial and polarisation degrees of freedom (DoF). As such, the demand for diversification of generation methods and characterization techniques have increased dramatically. Here we put forward a comprehensive tutorial about the use of DMDs in the generation and characterization of vector modes, providing details on the implementation of techniques that fully exploits the unsurpassed advantage of Digital Micromirrors Devices (DMDs), such as their high refresh rates and polarisation independence. We start by briefly describing the operating principles of DMD and follow with a thorough explanation of some of the methods to shape arbitrary vector modes. Finally, we describe some techniques aiming at the real-time characterization of vector beams. This tutorial highlights the value of DMDs as an alternative tool for the generation and characterization of complex vector light fields, of great relevance in a wide variety of applications.

scholarly journals Screening for the Optimal Specificity Profile of Protein Kinase C Using Electrospray Mass-Spectrometry

2005 ◽  
Vol 10 (4) ◽  
pp. 320-328 ◽  
Author(s):  
Mart Loog ◽  
Bo Ek ◽  
Nikita Oskolkov ◽  
Ale Närvänen ◽  
Jaak Järv ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase Activity ◽  
New Approach ◽  
Esi Ms ◽  
Kinase C ◽  
Kinase Specificity ◽  
Complex Structural ◽  
Novel Applications ◽  
Peptide Library Approach

A peptide library approach based on electrospray mass-spectrometric (ESI-MS) detection of phosphopeptides was designed for rapid and quantitative characterization of protein kinase specificity. The kcat/Km values for the protein kinase Cβ (PKCβ) were determined for a systematically varied set of individual substrate peptides in library mixtures by the ESI-MS method. The analysis revealed a complex structural specificity profile in positions around the phosphorylated serine with hydrophobic and/or basic residues being mostly preferred. On the basis of the kinetic parameters, a highly efficient peptide substrate for PKCβ (Kmvalue below 100 nM) FRRRRSFRRR and its alanine substituted pseudosubstrate-analog inhibitor (Ki value of 76 nM) were designed. The quantitative specificity profiles obtained by the new approach contained more information about kinase specificity than the conventional substrate consensus motifs. The new method presents a promising basis for design of substrate-site directed peptide or peptidomimetic inhibitors of protein kinases. Second, highly specific substrates could be designed for novel applications such as high-throughput protein kinase activity screens on protein kinase chips.

Variational characterization of real eigenvalues in linear viscoelastic oscillators

2017 ◽  
Vol 23 (10) ◽  
pp. 1377-1388 ◽  
Author(s):  
Seyyed Abbas Mohammadi ◽  
Heinrich Voss
Keyword(s):  
Degrees Of Freedom ◽  
Nonlinear Eigenvalue Problem ◽  
Eigenvalues And Eigenvectors ◽  
Variational Characterization ◽  
Viscoelastic System ◽  
New Approach ◽  
Motion Equations ◽  
Multiple Degrees Of Freedom ◽  
Linear Viscoelastic

This paper proposes a new approach for computing the real eigenvalues of a multiple-degrees-of-freedom viscoelastic system in which we assume an exponentially decaying damping. The free-motion equations lead to a nonlinear eigenvalue problem. If the system matrices are symmetric, the eigenvalues allow for a variational characterization of maxmin type, and the eigenvalues and eigenvectors can be determined very efficiently by the safeguarded iteration, which converges quadratically and, for extreme eigenvalues, monotonically. Numerical methods demonstrate the performance and the reliability of the approach. The method succeeds where some current approaches, with restrictive physical assumptions, fail.

Unified Rotational and Translational Stiffness Characterization of Compliant Shell Mechanisms

2018 ◽  
Author(s):  
Joost R. Leemans ◽  
Charles J. Kim ◽  
Werner W. P. J. van de Sande ◽  
Just L. Herder
Keyword(s):  
Degrees Of Freedom ◽  
Compliant Mechanisms ◽  
Screw Theory ◽  
Characterization Methods ◽  
Six Degrees Of Freedom ◽  
Thin Walled Structures ◽  
Spatial Mechanisms ◽  
Eigen Decomposition ◽  
Comprehensive Characterization

Compliant shell mechanisms utilize spatially curved thin-walled structures to transfer or transmit force, motion or energy through elastic deformation. To design with spatial mechanisms designers need comprehensive characterization methods, while existing methods fall short of meaningful comparisons between rotational and translational degrees of freedom. This paper presents two approaches, both of which are based on the principle of virtual loads and potential energy, utilizing properties of screw theory, Plücker coordinates and an eigen-decomposition, leading to two unification lengths that can be used to compare and visualize all six degrees of freedom directions and magnitudes of compliant mechanisms in a non-arbitrary physically meaningful manner.

On the Dynamic Isotropy of Mechanisms With Two Degrees of Freedom

2005 ◽  
Author(s):  
Raffaele Di Gregorio ◽  
Alessandro Cammarata ◽  
Rosario Sinatra
Keyword(s):  
Finite Number ◽  
Degrees Of Freedom ◽  
Point Of View ◽  
Closed Curves ◽  
Special Cases ◽  
Dynamic Performances ◽  
Definition Of ◽  
Geometric Locus

The comparison of mechanisms with different topology or with different geometry, but with the same topology, is a necessary operation during the design of a machine sized for a given task. Therefore, tools that evaluate the dynamic performances of a mechanism are welcomed. This paper deals with the dynamic isotropy of 2-dof mechanisms starting from the definition introduced in a previous paper. In particular, starting from the condition that identifies the dynamically isotropic configurations, it shows that, provided some special cases are not considered, 2-dof mechanisms have at most a finite number of isotropic configurations. Moreover, it shows that, provided the dynamically isotropic configurations are excluded, the geometric locus of the configuration space that collects the points associated to configurations with the same dynamic isotropy is constituted by closed curves. This results will allow the classification of 2-dof mechanisms from the dynamic-isotropy point of view, and the definition of some methodologies for the characterization of the dynamic isotropy of these mechanisms. Finally, examples of applications of the obtained results will be given.

scholarly journals Regeneration: Why junk DNA might matter

2018 ◽  
Author(s):  
Carlos Díaz-Castillo
Keyword(s):  
Natural Variation ◽  
Spatial Organization ◽  
Natural Phenomena ◽  
Collective Knowledge ◽  
Junk Dna ◽  
Research Fields ◽  
Biological Variables ◽  
The Individual

The ability of certain natural species to restore or regenerate missing structures has been a recurrent source of inspiration to forge our collective knowledge, from being used to adorn mythological figures with superhuman powers to permitting controlled reproducible observations that help setting the bases of entire research fields such as experimental biology and regenerative medicine. In spite of being one of the oldest natural phenomena under study, what makes certain species able or unable to regenerate missing parts is still largely a mystery. Recent advancements towards the highly detailed characterization of the sequence, the spatial organization, and the expression of genomes is offering a new standpoint to address the study of the natural variation in regenerative responses. An intriguing observation that has not yet conveniently pursued is that species with remarkable regenerative abilities tend to have genomes loaded with junk DNA (jDNA), i.e., genetic elements presumed to be useless for the benefit of the individual, whereas species for taxa with limited regenerative abilities tend to have jDNA-poor genomes. Here, I use existing knowledge on the role of jDNA as genome evolution facilitator and its non-random chromosome and nuclear distributions to speculate about two non-excluding ways through which the variation in jDNA genomic content might end up enhancing or limiting regenerative responses. The present piece aims to go beyond the confines of correlational studies between biological variables and to lay sensible conceptual grounds for future hypothesis-driven attempts to substantiate the genomic determinants of the natural variation of regenerative responses.

Design and Fabrication of a Multi-Functional Nanomanipulator

2009 ◽  
Vol 419-420 ◽  
pp. 21-24
Author(s):  
Ming Chang ◽  
Chia Hung Lin ◽  
Chung Po Lin ◽  
Juti Rani Deka
Keyword(s):  
Degrees Of Freedom ◽  
Electrical Characterization ◽  
The Body ◽  
Rapid Expansion ◽  
Nano Materials ◽  
Nano Fabrication ◽  
Permissible Range ◽  
Manipulation System

With rapid expansion of nanotechnology, microminiaturization has become imperative in the field of micro/nano fabrication. A nanomanipulation system with high degrees of freedom that can perform nanomachining, nanofabrication and mechanical/electrical characterization of nanoscale objects inside a scanning electron microscope (SEM) is presented. The manipulation system consists of several individual operating units each having three linear stages and one rotational stage. The body of the manipulator is designed using the idea of superposition. Each operating unit can move in the permissible range of SEM’s vacuum chamber and can increase or decrease the number of units according to the requirement. Experiments were executed to investigate the in-situ electrical resistance of nano materials.

scholarly journals Electromechanical Characterization and Locomotion Control of IPMC BioMicroRobot

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Martin J.-D. Otis
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Water Electrolysis ◽  
Laser Vibrometer ◽  
Metal Composite ◽  
Current Consumption ◽  
Polymer Metal ◽  
Multiple Frequencies ◽  
Electromechanical Characterization

This paper presents the electromechanical characterization of Nafion-Pt microlegs for the development of an insect-like hexapod BioMicroRobot (BMR). BMR microlegs are built using quasi-cylindrical Nafion-Pt ionomeric polymer-metal composite (IPMC), which has 2.5 degrees of freedom. The specific manufacturing process using a laser excimer for one leg in three-dimensional configurations is discussed. Dynamic behavior and microleg characteristics have been measured in deionized water using a laser vibrometer. The use of the laser vibrometer shows the linear characteristics between the duty cycle of square wave input and displacement rate of the actuator at multiple frequencies. This linearity is used to design a servo-system in order to reproduce insect tripod walking. As well, BMR current consumption is an important parameter evaluated for each leg. Current passing throughout the IPMC membrane can result in water electrolysis. Four methods are explained for avoiding electrolysis. The hardware test bench for measurements is presented. The purpose of this design is to control a BMR for biomedical goals such as implantation into a human body. Experimental results for the proposed propulsion system are conclusive for this type of bioinspired BMR.

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.

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