scholarly journals Toward an Estimation of the Optical Feedback Factor C on the Fly for Displacement Sensing

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3528
Author(s):  
Olivier D. Bernal ◽  
Usman Zabit ◽  
Francis Jayat ◽  
Thierry Bosch
Keyword(s):  
Optical Feedback ◽  
Sampling Frequency ◽  
Open Loop ◽  
Phase Unwrapping ◽  
Ease Of Use ◽  
Time Varying ◽  
Feedback Factor ◽  
Feedback Level ◽  
Factor C ◽  
Event Based

In this paper, a method based on the inherent event-based sampling capability of laser optical feedback interferometry (OFI) is proposed to assess the optical feedback factor C when the laser operates in the moderate and strong feedback regimes. Most of the phase unwrapping open-loop OFI algorithms rely on the estimation of C to retrieve the displacement with nanometric precision. Here, the proposed method operates in open-loop configuration and relies only on OFI’s fringe detection, thereby improving its robustness and ease of use. The proposed method is able to estimate C with a precision of <5%. The obtained performances are compared to three different approaches previously published and the impacts of phase noise and sampling frequency are reported. We also show that this method can assess C on the fly even when C is varying due to speckle. To the best of the authors’ knowledge, these are the first reported results of time-varying C estimation. In addition, through C estimation over time, it could pave the way not only to higher performance phase unwrapping algorithms but also to a better control of the optical feedback level via the use of an adaptive lens and thus to better displacement retrieval performances.

scholarly journals Optical Feedback Self-Mixing Interferometry With a Large Feedback Factor $C$: Behavior Studies

2009 ◽  
Vol 45 (7) ◽  
pp. 840-848 ◽  
Author(s):  
Yanguang Yu ◽  
Jiangtao Xi ◽  
Joe F. Chicharo ◽  
Thierry M. Bosch
Keyword(s):  
Optical Feedback ◽  
Feedback Factor ◽  
Factor C

scholarly journals BonZeb: open-source, modular software tools for high-resolution zebrafish tracking and analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicholas C. Guilbeault ◽  
Jordan Guerguiev ◽  
Michael Martin ◽  
Isabelle Tate ◽  
Tod R. Thiele
Keyword(s):  
High Resolution ◽  
Open Loop ◽  
Ease Of Use ◽  
Neural Mechanisms ◽  
Animal Tracking ◽  
Larval Zebrafish ◽  
Optogenetic Stimulation ◽  
Modular Software ◽  
Behavioral Tracking ◽  
Experimental Protocols

AbstractWe present BonZeb—a suite of modular Bonsai packages which allow high-resolution zebrafish tracking with dynamic visual feedback. Bonsai is an increasingly popular software platform that is accelerating the standardization of experimental protocols within the neurosciences due to its speed, flexibility, and minimal programming overhead. BonZeb can be implemented into novel and existing Bonsai workflows for online behavioral tracking and offline tracking with batch processing. We demonstrate that BonZeb can run a variety of experimental configurations used for gaining insights into the neural mechanisms of zebrafish behavior. BonZeb supports head-fixed closed-loop and free-swimming virtual open-loop assays as well as multi-animal tracking, optogenetic stimulation, and calcium imaging during behavior. The combined performance, ease of use and versatility of BonZeb opens new experimental avenues for researchers seeking high-resolution behavioral tracking of larval zebrafish.

scholarly journals Shift a laser beam back and forth to exchange heat and work in thermodynamics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
John A. C. Albay ◽  
Zhi-Yi Zhou ◽  
Cheng-Hung Chang ◽  
Yonggun Jun
Keyword(s):  
Optical Feedback ◽  
Brownian Particle ◽  
Time Varying ◽  
Optical Technique ◽  
Work Related ◽  
Engine Efficiency ◽  
Confining Potential ◽  
Equipartition Theorem ◽  
Virtual Temperature ◽  
High Flexibility

AbstractAlthough the equivalence of heat and work has been unveiled since Joule’s ingenious experiment in 1845, they rarely originate from the same source in experiments. In this study, we theoretically and experimentally demonstrated how to use a high-precision optical feedback trap to combine the generation of virtual temperature and potential to simultaneously manipulate the heat and work of a small system. This idea was applied to a microscopic Stirling engine consisting of a Brownian particle under a time-varying confining potential and temperature. The experimental results justified the position and the velocity equipartition theorem, confirmed several theoretically predicted energetics, and revealed the engine efficiency as well as its trade-off relation with the output power. The small theory–experiment discrepancy and high flexibility of the swift change of the particle condition highlight the advantage of this optical technique and prove it to be an efficient way for exploring heat and work-related issues in the modern thermodynamics for small systems.

scholarly journals Integrated sample-handling and mounting system for fixed-target serial synchrotron crystallography

2021 ◽  
Vol 77 (5) ◽  
pp. 628-644
Author(s):  
Gabrielle Illava ◽  
Richard Jayne ◽  
Aaron D. Finke ◽  
David Closs ◽  
Wenjie Zeng ◽  
...  
Keyword(s):  
Data Collection ◽  
Integrated System ◽  
Ease Of Use ◽  
Time Varying ◽  
Fixed Target ◽  
Sample Handling ◽  
Small Crystals ◽  
Fixed Orientation ◽  
Common Problems ◽  
Liquid Flows

Serial synchrotron crystallography (SSX) is enabling the efficient use of small crystals for structure–function studies of biomolecules and for drug discovery. An integrated SSX system has been developed comprising ultralow background-scatter sample holders suitable for room and cryogenic temperature crystallographic data collection, a sample-loading station and a humid `gloveless' glovebox. The sample holders incorporate thin-film supports with a variety of designs optimized for different crystal-loading challenges. These holders facilitate the dispersion of crystals and the removal of excess liquid, can be cooled at extremely high rates, generate little background scatter, allow data collection over >90° of oscillation without obstruction or the risk of generating saturating Bragg peaks, are compatible with existing infrastructure for high-throughput cryocrystallography and are reusable. The sample-loading station allows sample preparation and loading onto the support film, the application of time-varying suction for optimal removal of excess liquid, crystal repositioning and cryoprotection, and the application of sealing films for room-temperature data collection, all in a controlled-humidity environment. The humid glovebox allows microscope observation of the sample-loading station and crystallization trays while maintaining near-saturating humidities that further minimize the risks of sample dehydration and damage, and maximize working times. This integrated system addresses common problems in obtaining properly dispersed, properly hydrated and isomorphous microcrystals for fixed-orientation and oscillation data collection. Its ease of use, flexibility and optimized performance make it attractive not just for SSX but also for single-crystal and few-crystal data collection. Fundamental concepts that are important in achieving desired crystal distributions on a sample holder via time-varying suction-induced liquid flows are also discussed.

Decentralized MRAC for Large-Scale Interconnected Systems With State and Input Delays by Integrators Inclusion

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Seyed Hamid Hashemipour ◽  
Nastaran Vasegh ◽  
Ali Khaki Sedigh
Keyword(s):  
Large Scale ◽  
Practical Method ◽  
Open Loop ◽  
Loop System ◽  
Input Delay ◽  
Time Varying ◽  
Delay Compensation ◽  
State And Input Delays ◽  
Input Delays ◽  
Model Reference Adaptive

This paper investigates the problem of decentralized model reference adaptive control (MRAC) for a class of large-scale systems with time-varying delays in the interconnected terms and state and input delays. The upper bounds of interconnection terms with time-varying delays and external disturbances are assumed to be completely unknown. By integrators inclusion, a dynamic input delay compensator is established for input delay compensation and it is used as a practical method for state calculation x(t + R). Also, a method is presented for a class of decentralized feedback controllers, which can evolve the closed-loop system error uniformly bounded stable. As a numerical example, the proposed technique is applied to an unstable open-loop system to show the feasibility and effectiveness of the method.

Electrostatic Aberration Correction in LV-SEM

2000 ◽  
Vol 6 (S2) ◽  
pp. 746-747 ◽  
Author(s):  
D.J. Maas ◽  
A. Henstra ◽  
M.P.C.M. Krijn ◽  
S.A.M. Mentink
Keyword(s):  
Electron Microscope ◽  
Low Voltage ◽  
State Of The Art ◽  
Spherical Aberration ◽  
Positive Definite ◽  
Ease Of Use ◽  
Objective Lens ◽  
Time Varying ◽  
Voltage Electron ◽  
Aberration Corrected

The resolution of a low-voltage electron microscope is limited by the chromatic and spherical aberration of the objective lens, see Fig. 1. The design of state-of-the-art objective lenses is optimised for minimal aberrations. Any significant improvement of the resolution requires an aberration corrector. Recently, correction of both Cc and Cs has been demonstrated in SEM, using a combination of magnetic and electrostatic quadrupoles and octupoles (Zach and Haider, 1995). The present paper presents an alternative design, which is based on a purely electrostatic concept, potentially simplifying the ease-of-use of an aberration corrected microscope.In 1936 Scherzer showed that the fundamental lens aberrations of round lenses are positive definite, in absence of time-varying fields and/or space charge. Negative lens aberrations, required for the correction of Cc and Cs, can only be obtained using non-round lenses, e.g. quadrupoles and octupoles (Scherzer, 1947).

Plans and The Structure of Target Acquisition Behavior

1981 ◽  
Vol 25 (1) ◽  
pp. 571-575
Author(s):  
R. A. Miller ◽  
R. J. Jagacinski ◽  
R. B. Nalavade ◽  
W. W. Johnson
Keyword(s):  
Closed Loop ◽  
Position Control ◽  
Open Loop ◽  
General Strategy ◽  
Velocity Control ◽  
Additional Time ◽  
First Order ◽  
Oscilloscope Screen ◽  
Activity Sequence ◽  
Event Based

Subjects manipulated a position control stick with one hand and a velocity control stick with the other hand in order to capture a moving target displayed on an oscilloscope screen. The two control sticks were additively coupled. In order to understand the coordination of the two control sticks, event-based first-order markov “activity sequence generators” were constructed for individual subjects. These discrete probabilistic structures are closely related to each subject's overall plan or general strategy for the capture task. Striking individual differences and strategic errors in performance were revealed. When combined with additional time-conditioned (open-loop) and error-conditioned (closed-loop) details, the activity sequence generators provide a basis for a hierarchic description of this perceptual-motor skill.

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