The mirror neuron system: new frontiers.

Science.gov (United States)

Keysers, Christian; Fadiga, Luciano

2008-01-01

Since the discovery of mirror neurons, much effort has been invested into studying their location and properties in the human brain. Here we review these original findings and introduce the main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror system embedded into the mosaic of circuits that compose our brain? How does the mirror system contribute to communication, language and social interaction? Can the principle of mirror neurons be extended to emotions, sensations and thoughts? Papers using a wide range of methods, including single cell recordings, fMRI, TMS, EEG and psychophysics, collected in this special issue, start to give us some impressive answers.

Sensorimotor learning configures the human mirror system.

Science.gov (United States)

Catmur, Caroline; Walsh, Vincent; Heyes, Cecilia

2007-09-04

Cells in the "mirror system" fire not only when an individual performs an action but also when one observes the same action performed by another agent [1-4]. The mirror system, found in premotor and parietal cortices of human and monkey brains, is thought to provide the foundation for social understanding and to enable the development of theory of mind and language [5-9]. However, it is unclear how mirror neurons acquire their mirror properties -- how they derive the information necessary to match observed with executed actions [10]. We address this by showing that it is possible to manipulate the selectivity of the human mirror system, and thereby make it operate as a countermirror system, by giving participants training to perform one action while observing another. Before this training, participants showed event-related muscle-specific responses to transcranial magnetic stimulation over motor cortex during observation of little- and index-finger movements [11-13]. After training, this normal mirror effect was reversed. These results indicate that the mirror properties of the mirror system are neither wholly innate [14] nor fixed once acquired; instead they develop through sensorimotor learning [15, 16]. Our findings indicate that the human mirror system is, to some extent, both a product and a process of social interaction.

Physics of mirror fusion systems

International Nuclear Information System (INIS)

Post, R.F.

1976-01-01

Recent experimental results with the 2XIIB mirror machine at Lawrence Livermore Laboratory have demonstrated the stable confinement of plasmas at fusion temperatures and with energy densities equaling or exceeding that of the confining fields. The physics of mirror confinement is discussed in the context of these new results. Some possible approaches to further improving the confinement properties of mirror systems and the impact of these new approaches on the prospects for mirror fusion reactors are discussed

Physics of mirror systems

International Nuclear Information System (INIS)

Post, R.F.

1982-05-01

In recent years the emphasis in research on the magnetic mirror approach to fusion has been shifted to address what are essentially economically-motivated issues. The introduction of the Tandem Mirror idea solved in principal the problem of low Q (low fusion power gain) of mirror-based fusion systems. In order to optimize the tandem mirror idea from an economic standpoint, some important improvements have been suggested. These improvements include the thermal barrier idea of Baldwin and Logan and the axicell concept of Kesner. These new modifications introduce some special physics considerations. Among these are (1) The MHD stability properties of high energy electron components in the end cells; (2) The optimization of end-cell magnetic field configurations with the objective of minimizing equilibrium parallel currents; (3) The suppression of microstabilities by use of sloshing ion distributions. Following a brief outline of tandem mirror concepts, the above three topics are discussed, with illustrative examples taken from earlier work or from recent design studies

The mirror neuron system : New frontiers

NARCIS (Netherlands)

Keysers, Christian; Fadiga, Luciano

2008-01-01

Since the discovery of mirror neurons, much effort has been invested into Studying their location and properties in the human brain. Here we review these original findings and introduce the Main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror

X-ray imaging with toroidal mirror

International Nuclear Information System (INIS)

Aoki, Sadao; Sakayanagi, Yoshimi

1978-01-01

X-ray imaging is made with a single toroidal mirror or two successive toroidal mirrors. Geometrical images at the Gaussian image plane are described by the ray trace. Application of a single toroidal mirror to small-angle scattering is presented. (author)

Mirror system based therapy for autism spectrum disorders

Institute of Scientific and Technical Information of China (English)

Wei CHEN; Jing ZHANG; Jun DING

2008-01-01

This paper reviews the present theories and empirical research of autisms' cognitive research and mir-ror systems and introduces a new hypothesis about the causes of autism spectrum disorders (ASD): autistic mir-ror neuron dysfunction hypothesis. ASD subjects show obvious lack of the activation of the mirror system during the task of observation or emotional cognition. It is sig-nificant to investigate the mirror system for revealing the causes of autism and it is also helpful for developing new ways to diagnose or treat this disorder.

Mirror Fusion Test Facility magnet system

International Nuclear Information System (INIS)

VanSant, J.H.; Kozman, T.A.; Bulmer, R.H.; Ng, D.S.

1981-01-01

In 1979, R.H. Bulmer of Lawrence Livermore National Laboratory (LLNL) discussed a proposed tandem-mirror magnet system for the Mirror Fusion Test Facility (MFTF) at the 8th symposium on Engineering Problems in Fusion Research. Since then, Congress has voted funds for expanding LLNL's MFTF to a tandem-mirror facility (designated MFTF-B). The new facility, scheduled for completion by 1985, will seek to achieve two goals: (1) Energy break-even capability (Q or the ratio of fusion energy to plasma heating energy = 1) of mirror fusion, (2) Engineering feasibility of reactor-scale machines. Briefly stated, 22 superconducting magnets contained in a 11-m-diam by 65-m-long vacuum vessel will confine a fusion plasma fueled by 80 axial streaming-plasma guns and over 40 radial neutral beams. We have already completed a preliminary design of this magnet system

AFOCAL SYSTEMS FORMED BY MIRROR OFF-AXIS PARABOLOID

Directory of Open Access Journals (Sweden)

N. K. Artiukhina

2017-01-01

Full Text Available Mirror systems make it possible to reduce device dimensions and its weight while preserving high input aperture and these systems are characterized by a number of other advantages. Their significant disadvantage is a central screening of an entrance pupil that leads to lower image quality. The paper contains description of the investigations on afocal systems formed by eccentrically cut-out mirror paraboloids (off-axis mirrors where aperture diaphragm is displaced in the meridian plane for a defined value and a central field point is located on the optical axis. The canonic Mersenne systems are accepted as base schemas (modules for these compositions. The paper considers two types of such systems: visible increases – Г > 0 and Г < 0. Algorithms for calculation of centered afocal systems with two and four reflections have been written in the paper and the systems are free from spherical aberration, coma, astigmatism when an input pupil is located in superimposed focal planes of all parabolic mirrors. An aberration in curvature image has been additionally corrected in three-mirror quart-parabolic scheme which is a combination of two classical telescopic Mersenne systems. The paper presents schemes and calculation results. Two-mirror schemes with non-screened input pupil have been studied in the paper and in this case all the system remains centered and an aperture diaphragm is decentered for the distance Cm which is commensurable with the diaphragm size. The paper contains description of the investigated afocal schemes with four reflections from off-axis mirror paraboloids, a prepared algorithm for calculation, the obtained formulas for making combination of canonic afocal systems formed by two mirrors. Computer simulation in software environment Opal and Zemax has been carried out in the paper. Basic description has been prepared while using two alternative methods for the class of decentered systems and aberration characteristics and

Secondary mirror system for the European Solar Telescope (EST)

Science.gov (United States)

Cavaller, L.; Siegel, B.; Prieto, G.; Hernandez, E.; Casalta, J. M.; Mercader, J.; Barriga, J.

2010-07-01

The European Solar Telescope (EST) is a European collaborative project to build a 4m class solar telescope in the Canary Islands, which is now in its design study phase. The telescope will provide diffraction limited performance for several instruments observing simultaneously at the Coudé focus at different wavelengths. A multi-conjugated adaptive optics system composed of a tip-tilt mirror and several deformable mirrors will be integrated in the telescope optical path. The secondary mirror system is composed of the mirror itself (Ø800mm), the alignment drives and the cooling system needed to remove the solar heat load from the mirror. During the design study the feasibility to provide fast tip-tilt capabilities at the secondary mirror to work as the adaptive optics tip-tilt mirror is also being evaluated.

Stability design considerations for mirror support systems in ICF lasers

International Nuclear Information System (INIS)

Tietbohl, G.L.; Sommer, S.C.

1996-10-01

Some of the major components of laser systems used for Inertial Confinement Fusion (ICF) are the large aperture mirrors which direct the path of the laser. These mirrors are typically supported by systems which consist of mirror mounts, mirror enclosures, superstructures, and foundations. Stability design considerations for the support systems of large aperture mirrors have been developed based on the experience of designing and evaluating similar systems at the Lawrence Livermore National Laboratory (LLNL). Examples of the systems developed at LLNL include Nova, the Petawatt laser, Beamlet, and the National Ignition Facility (NIF). The structural design of support systems of large aperture mirrors has typically been controlled by stability considerations in order for the large laser system to meet its performance requirements for alignment and positioning. This paper will discuss the influence of stability considerations and will provide guidance on the structural design and evaluation of mirror support systems in ICF lasers so that this information can be used on similar systems

The mirror system in human and nonhuman primates.

Science.gov (United States)

Orban, Guy A

2014-04-01

The description of the mirror neuron system provided by Cook et al. is incomplete for the macaque, and incorrect for humans. This is relevant to exaptation versus associative learning as the underlying mechanism generating mirror neurons, and to the sensorimotor learning as evidence for the authors' viewpoint. The proposed additional testing of the mirror system in rodents is unrealistic.

Operation of the NSTX Thomson Scattering System

International Nuclear Information System (INIS)

LeBlanc, B.P.; Bell, R.E.; Johnson, D.W.; Hoffman, D.E.; Long, D.C.; Palladino, R.W.

2002-01-01

The NSTX multi-point Thomson scattering system has been in operation for nearly two years and provides routine Te(R,t) and ne(R,t) measurements. The laser beams from two 30-Hz Nd:YAG lasers are imaged by a spherical mirror onto 36 fiber-optics bundles. In the present configuration, the output ends of 20 of these bundles are instrumented with filter polychromators and avalanche photodiode detectors. In this paper, we discuss the laser implementation and the installed collection optics. We follow with examples of raw and analyzed data. We close with some comments about calibration

Novel electro-hydraulic position control system for primary mirror supporting system

Directory of Open Access Journals (Sweden)

Xiongbin Peng

2016-05-01

Full Text Available In the field of modern large-scale telescope, primary mirror supporting system technology faces the difficulties of theoretically uniform output force request and bias compensation. Therefore, a novel position control system combining hydraulic system with servo motor system is introduced. The novel system ensures uniform output force on supporting points without complicating the mechanical structure. The structures of both primary mirror supporting system and novel position system are described. Then, the mathematical model of novel position control system is derived for controller selection. A proportional–derivative controller is adopted for simulations and experiments of step response and triangle path tracking. The results show that proportional–derivative controller guarantees the system with micrometer-level positioning ability. A modified proportional–derivative controller is utilized to promote system behavior with faster response overshoot. The novel position control system is then applied on primary mirror supporting system. Coupling effect is observed among actuator partitions, and relocation of virtual pivot supporting point is chosen as the decoupling measurement. The position keeping ability of the primary mirror supporting system is verified by rotating the mirror cell at a considerably high rate. The experiment results show that the decoupled system performs better with smaller bias and shorter recovery time.

Physics issues in mirror and tandem mirror systems

International Nuclear Information System (INIS)

Post, R.F.

1984-01-01

Over the years the study of the confinement of high temperature plasma in magnetic mirror systems has presented researchers with many unusual physics problems. Many of these issues are by now understood theoretically and documented experimentally. With the advent of the tandem mirror idea, some new issues have emerged and are now under intensive study. These include: (1) the generation and control of ambipolar confining potentials and their effect on axial confinement and, (2) the combined influence of nonaxisymmetric magnetic fields (used to ensure MHD stability) and electric magnetic particle drifts on radial transport. Physics considerations associated with these two categories of issues will be reviewed, including concepts for the control of radial transport, under study or proposed

Anomalous transport in mirror systems

International Nuclear Information System (INIS)

Post, R.F.

1979-01-01

As now being explored for fusion applications confinement systems based on the mirror principle embody two kinds of plasma regimes. These two regimes are: (a) high-beta plasmas, stabilized against MHD and other low frequency plasma instabilities by magnetic-well fields, but characterized by non-Maxwellian ion distributions; (b) near-Maxwellian plasmas, confined electrostatically (as in the tandem mirror) or in a field-reversed region within the mirror cell. Common to both situations are the questions of anomalous transport owing to high frequency instabilities in the non-maxwellian portions of the plasmas. This report will summarize the status of theory and of experimental data bearing on these questions, with particular reference to the high temperature regimes of interest for fusion power

Control and automation of the Pegasus multi-point Thomson scattering system

Energy Technology Data Exchange (ETDEWEB)

Bodner, G. M., E-mail: gbodner@wisc.edu; Bongard, M. W.; Fonck, R. J.; Reusch, J. A.; Rodriguez Sanchez, C.; Schlossberg, D. J. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2016-11-15

A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. Additionally, the system has been upgraded with a set of fast (∼1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

Extending the mirror neuron system model, II: what did I just do? A new role for mirror neurons.

Science.gov (United States)

Bonaiuto, James; Arbib, Michael A

2010-04-01

A mirror system is active both when an animal executes a class of actions (self-actions) and when it sees another execute an action of that class. Much attention has been given to the possible roles of mirror systems in responding to the actions of others but there has been little attention paid to their role in self-actions. In the companion article (Bonaiuto et al. Biol Cybern 96:9-38, 2007) we presented MNS2, an extension of the Mirror Neuron System model of the monkey mirror system trained to recognize the external appearance of its own actions as a basis for recognizing the actions of other animals when they perform similar actions. Here we further extend the study of the mirror system by introducing the novel hypotheses that a mirror system may additionally help in monitoring the success of a self-action and may also be activated by recognition of one's own apparent actions as well as efference copy from one's intended actions. The framework for this computational demonstration is a model of action sequencing, called augmented competitive queuing, in which action choice is based on the desirability of executable actions. We show how this "what did I just do?" function of mirror neurons can contribute to the learning of both executability and desirability which in certain cases supports rapid reorganization of motor programs in the face of disruptions.

Magnetic mirror fusion systems: Characteristics and distinctive features

International Nuclear Information System (INIS)

Post, R.F.

1987-01-01

A tutorial account is given of the main characteristics and distinctive features of conceptual magnetic fusion systems employing the magnetic mirror principle. These features are related to the potential advantages that mirror-based fusion systems may exhibit for the generation of economic fusion power

Mirror Neuron System and Mentalizing System connect during online social interaction.

Science.gov (United States)

Sperduti, Marco; Guionnet, Sophie; Fossati, Philippe; Nadel, Jacqueline

2014-08-01

Two sets of brain areas are repeatedly reported in neuroimaging studies on social cognition: the Mirror Neuron System and the Mentalizing System. The Mirror System is involved in goal understanding and has been associated with several emotional and cognitive functions central to social interaction, ranging from empathy to gestural communication and imitation. The Mentalizing System is recruited in tasks requiring cognitive processes such as self-reference and understanding of other's intentions. Although theoretical accounts for an interaction between the two systems have been proposed, little is known about their synergy during social exchanges. In order to explore this question, we have recorded brain activity by means of functional MRI during live social exchanges based on reciprocal imitation of hand gestures. Here, we investigate, using the method of psychophysiological interaction, the changes in functional connectivity of the Mirror System due to the conditions of interest (being imitated, imitating) compared with passive observation of hand gestures. We report a strong coupling between the Mirror System and the Mentalizing System during the imitative exchanges. Our findings suggest a complementary role of the two networks during social encounters. The Mirror System would engage in the preparation of own actions and the simulation of other's actions, while the Mentalizing System would engage in the anticipation of the other's intention and thus would participate to the co-regulation of reciprocal actions. Beyond a specific effect of imitation, the design used offers the opportunity to tackle the role of role-switching in an interpersonal account of social cognition.

Robotic Mirror Therapy System for Functional Recovery of Hemiplegic Arms.

Science.gov (United States)

Beom, Jaewon; Koh, Sukgyu; Nam, Hyung Seok; Kim, Wonshik; Kim, Yoonjae; Seo, Han Gil; Oh, Byung-Mo; Chung, Sun Gun; Kim, Sungwan

2016-08-15

Mirror therapy has been performed as effective occupational therapy in a clinical setting for functional recovery of a hemiplegic arm after stroke. It is conducted by eliciting an illusion through use of a mirror as if the hemiplegic arm is moving in real-time while moving the healthy arm. It can facilitate brain neuroplasticity through activation of the sensorimotor cortex. However, conventional mirror therapy has a critical limitation in that the hemiplegic arm is not actually moving. Thus, we developed a real-time 2-axis mirror robot system as a simple add-on module for conventional mirror therapy using a closed feedback mechanism, which enables real-time movement of the hemiplegic arm. We used 3 Attitude and Heading Reference System sensors, 2 brushless DC motors for elbow and wrist joints, and exoskeletal frames. In a feasibility study on 6 healthy subjects, robotic mirror therapy was safe and feasible. We further selected tasks useful for activities of daily living training through feedback from rehabilitation doctors. A chronic stroke patient showed improvement in the Fugl-Meyer assessment scale and elbow flexor spasticity after a 2-week application of the mirror robot system. Robotic mirror therapy may enhance proprioceptive input to the sensory cortex, which is considered to be important in neuroplasticity and functional recovery of hemiplegic arms. The mirror robot system presented herein can be easily developed and utilized effectively to advance occupational therapy.

Plasma surface interactions in Q-enhanced mirror systems

International Nuclear Information System (INIS)

Post, R.F.

1978-01-01

Two approaches to enhancement of the Q (energy gain) factor of mirror systems are under study at Livermore. These include the Tandem Mirror and the Field Reversed Mirror. Both of these new ideas preserve features of conventional mirror systems as far as plasma-wall interactions are concerned. Specifically in both approaches field lines exit from the ends of the system and impinge on walls located at a distance from the confinement chamber. It is possible to predict some aspects of the plasma/surface interactions of TM and FRM systems from experience obtained in the Livermore 2XIIB experiment. In particular, as observed in 2XIIB, effective isolation of the plasma from thermal contact with the ends owing to the development of sheath-like regions is to be expected. Studies presently underway directed toward still further enhancing the decoupling of the plasma from the effects of plasma surface interactions at the walls will be discussed, with particular reference to the problem of minimizing the effects of refluxing secondary electrons produced by plasma impact on the end walls

Transmission X-ray mirror

International Nuclear Information System (INIS)

Lairson, B.M.; Bilderback, D.H.

1982-01-01

Transmission X-ray mirrors have been made from 400 A to 10 000 A thick soap films and have been shown to have novel properties. Using grazing angles of incidence, low energy X-rays were reflected from the front surface while more energetic X-rays were transmitted through the mirror largely unattenuated. A wide bandpass monochromator was made from a silicon carbide mirror followed by a soap film transmission mirror and operated in the white beam at the cornell High Energy Synchrotron Source (CHESS). Bandpasses of ΔE/E=12% to 18% were achieved at 13 keV with peak efficiencies estimated to be between 55% and 75%, respectively. Several wide angle scattering photographs of stretched polyethylene and a phospholipid were obtained in 10 s using an 18% bandpass. (orig.)

Summary of Thomson-scattering data from the Tandem Mirror Experiment (TMX)

International Nuclear Information System (INIS)

Goodman, R.K.

1982-01-01

We provide a synthesis of our Thomson-scattering measurements of electron temperature (T/sub e/) and density (n/sub e/) for the Tandem Mirror Experiment (TMX). TMX operated in two modes - high and low T/sub e/. When performing in the high T/sub e/ mode (in general > 100 eV), heating the central-cell ions with neutral beams raised T/sub e/ in the end plug. We achieved a maximum T/sub e/ of 260 eV in the east end plug. Specifically, our experiments demonstrated that in the end plug, the radial T/sub e/ profiles were flat to r = 5 cm; the ratio of potential (phi/sub p/) to T/sub e/ ranged between four and six. In addition, we found that although T/sub e/ in the central cell was generally comparable to that in the plug, it was often not constant along a magnetic field line. Under some conditions a non-Maxwellian electron distribution may have been present

Confinement and Isotropization of Galactic Cosmic Rays by Molecular-Cloud Magnetic Mirrors When Turbulent Scattering Is Weak

International Nuclear Information System (INIS)

Chandran, Benjamin D. G.

2000-01-01

Theoretical studies of magnetohydrodynamic (MHD) turbulence and observations of solar wind fluctuations suggest that MHD turbulence in the interstellar medium is anisotropic at small scales, with smooth variations along the background magnetic field and sharp variations perpendicular to the background field. Turbulence with this anisotropy is inefficient at scattering cosmic rays, and thus the scattering rate ν may be smaller than has been traditionally assumed in diffusion models of Galactic cosmic-ray propagation, at least for cosmic-ray energies E above 1011-1012 eV at which self-confinement is not possible. In this paper, it is shown that Galactic cosmic rays can be effectively confined through magnetic reflection by molecular clouds, even when turbulent scattering is weak. Elmegreen's quasi-fractal model of molecular-cloud structure is used to argue that a typical magnetic field line passes through a molecular cloud complex once every ∼300 pc. Once inside the complex, the field line will in most cases be focused into one or more dense clumps in which the magnetic field can be much stronger than the average field in the intercloud medium (ICM). Cosmic rays following field lines into cloud complexes are most often magnetically reflected back into the ICM, since strong-field regions act as magnetic mirrors. For a broad range of cosmic-ray energies, a cosmic ray initially following some particular field line separates from that field line sufficiently slowly that the cosmic ray can be trapped between neighboring cloud complexes for long periods of time. The suppression of cosmic-ray diffusion due to magnetic trapping is calculated in this paper with the use of phenomenological arguments, asymptotic analysis, and Monte Carlo particle simulations. Formulas for the coefficient of diffusion perpendicular to the Galactic disk are derived for several different parameter regimes within the E-ν plane. In one of these parameter regimes in which scattering is weak, it

Material Assessment for ITER’s Collective Thomson Scattering first mirror

DEFF Research Database (Denmark)

Santos, R.; Policarpo, H.; Gonçalves, B.

2015-01-01

Element Analysis (FEA) of the mirror over a 400s discharge (reasonable number for computational tests, since an ITER discharge will be between 200 s and 1000 s) , with and without mirror cooling, is performed. The results obtained in this preliminary analysis show that of the tested materials Mo and W....... In this work, three different materials (molybdenum (Mo), stainless steel 316L (SS-316L) and tungsten (W)) are considered for the first mirror of the CTS. The objective is to assess the suitability of these materials for this mirror and to provide a first ranking, considering the neutron radiation loads...... are the most suitable materials for this application, being able to reliably sustain the thermal and structural stresses imposed by the neutron loads....

The infant mirror neuron system studied with high density EEG.

Science.gov (United States)

Nyström, Pär

2008-01-01

The mirror neuron system has been suggested to play a role in many social capabilities such as action understanding, imitation, language and empathy. These are all capabilities that develop during infancy and childhood, but the human mirror neuron system has been poorly studied using neurophysiological measures. This study measured the brain activity of 6-month-old infants and adults using a high-density EEG net with the aim of identifying mirror neuron activity. The subjects viewed both goal-directed movements and non-goal-directed movements. An independent component analysis was used to extract the sources of cognitive processes. The desynchronization of the mu rhythm in adults has been shown to be a marker for activation of the mirror neuron system and was used as a criterion to categorize independent components between subjects. The results showed significant mu desynchronization in the adult group and significantly higher ERP activation in both adults and 6-month-olds for the goal-directed action observation condition. This study demonstrate that infants as young as 6 months display mirror neuron activity and is the first to present a direct ERP measure of the mirror neuron system in infants.

The human mirror neuron system and embodied representations.

Science.gov (United States)

Aziz-Zadeh, Lisa; Ivry, Richard B

2009-01-01

Mirror neurons are defined as neurons in the monkey cortex which respond to goal oriented actions, whether the behavior is self-generated or produced by another. Here we briefly review this literature and consider evidence from behavioral, neuropsychological, and brain imaging studies for a similar mirror neuron system in humans. Furthermore, we review functions of this system related to action comprehension and motor imagery, as well as evidence for speculations on the system's ties with conceptual knowledge and language.

The mirror neuron system and the consequences of its dysfunction.

Science.gov (United States)

Iacoboni, Marco; Dapretto, Mirella

2006-12-01

The discovery of premotor and parietal cells known as mirror neurons in the macaque brain that fire not only when the animal is in action, but also when it observes others carrying out the same actions provides a plausible neurophysiological mechanism for a variety of important social behaviours, from imitation to empathy. Recent data also show that dysfunction of the mirror neuron system in humans might be a core deficit in autism, a socially isolating condition. Here, we review the neurophysiology of the mirror neuron system and its role in social cognition and discuss the clinical implications of mirror neuron dysfunction.

Managing Risk on a Technology Development Project/Advanced Mirror System Demonstrator

Science.gov (United States)

Byberg, Alicia; Russell, J. Kevin; Stahl, Phil (Technical Monitor)

2002-01-01

The risk management study applied to the Advanced Mirror System Demonstrator (AMSD), a precursor mirror technology development for the Next Generation Space Telescope (NGST) is documented. The AMSD will be developed as a segment of a lightweight primary mirror system that can be produced at a low cost and with a short manufacturing schedule. The technology gained from the program will support the risk mitigation strategy for the NGST, as well as other government agency space mirror programs.

Calibration of the mirror system in the HERA-B RICH

International Nuclear Information System (INIS)

Staric, Marko; Krizan, Peter

2008-01-01

The mirror system of the HERA-B ring imaging Cherenkov (RICH) counter consists of two spherical and two planar mirrors, composed of altogether 116 mirror segments. Analysis of displacements of the Cherenkov ring center relative to the charged particle track, for given spherical-planar segment pairs, leads to accurate information regarding the orientation of individual mirror segments. The method for mirror calibration is described and the effect of applying the required corrections on the Cherenkov angle resolution of the HERA-B RICH is discussed

Four-Mirror Freeform Reflective Imaging Systems

Data.gov (United States)

National Aeronautics and Space Administration — Central Objectives: The research involves a revelation of the solution space for revolutionary families of four-mirror freeform reflective imaging systems. A...

Multiple-scattering in radar systems: A review

International Nuclear Information System (INIS)

Battaglia, Alessandro; Tanelli, Simone; Kobayashi, Satoru; Zrnic, Dusan; Hogan, Robin J.; Simmer, Clemens

2010-01-01

Although extensively studied within the lidar community, the multiple scattering phenomenon has always been considered a rare curiosity by radar meteorologists. Up to few years ago its appearance has only been associated with two- or three-body-scattering features (e.g. hail flares and mirror images) involving highly reflective surfaces. Recent atmospheric research aimed at better understanding of the water cycle and the role played by clouds and precipitation in affecting the Earth's climate has driven the deployment of high frequency radars in space. Examples are the TRMM 13.5 GHz, the CloudSat 94 GHz, the upcoming EarthCARE 94 GHz, and the GPM dual 13-35 GHz radars. These systems are able to detect the vertical distribution of hydrometeors and thus provide crucial feedbacks for radiation and climate studies. The shift towards higher frequencies increases the sensitivity to hydrometeors, improves the spatial resolution and reduces the size and weight of the radar systems. On the other hand, higher frequency radars are affected by stronger extinction, especially in the presence of large precipitating particles (e.g. raindrops or hail particles), which may eventually drive the signal below the minimum detection threshold. In such circumstances the interpretation of the radar equation via the single scattering approximation may be problematic. Errors will be large when the radiation emitted from the radar after interacting more than once with the medium still contributes substantially to the received power. This is the case if the transport mean-free-path becomes comparable with the instrument footprint (determined by the antenna beam-width and the platform altitude). This situation resembles to what has already been experienced in lidar observations, but with a predominance of wide- versus small-angle scattering events. At millimeter wavelengths, hydrometeors diffuse radiation rather isotropically compared to the visible or near infrared region where scattering is

Tandem Mirror Reactor Systems Code (Version I)

International Nuclear Information System (INIS)

Reid, R.L.; Finn, P.A.; Gohar, M.Y.

1985-09-01

A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to determine the impact of center cell plasma radius, length, and ion temperature on reactor cost and performance at constant fusion power; and (2) to determine the impact of reactor power level on cost

Neutron scattering equipments in JAERI. Current status

International Nuclear Information System (INIS)

Hamaguchi, Yoshikazu; Minakawa, Nobuaki

2003-01-01

24 neutron scattering instruments are installed in the JRR-3M research reactor. Among them JAERI has 12 neutron scattering instruments. Those instruments are HRPD for high-resolution structural analysis, TAS-1 and TAS-2 for elastic and inelastic scattering and for magnetic scattering measurements by the polarized neutron, LTAS for elastic and inelastic scattering measurement at a low energy region, and for neutron device development, PNO for topography and for very small angle scattering measurement in a small Q range, NRG for neutron radiography, RESA for internal strain measurements, SANS for the molecule and semi-macroscopic magnetic structural analysis, BIX-2 and BIX-3 for the biological structural analysis research, and PGA for the research of prompt gamma-ray analysis. The university groups have 12 neutron scattering instruments. Since those instruments were installed at the period when JRR-3M was completed, about 10 years have passed. In order to match the old control systems with the progress of recent computer technologies, and peripheral equipment, numbers of instruments are being renewed. In the neutron guide hall of JRR-3M, the Ni mirror guide tube was replaced by a super mirror guide tube to increase neutron flux. The intensity of 2A flux was increased by a factor of about two. (J.P.N.)

Study of a high finesse four mirrors Fabry Perot cavity for X-rays and Gamma rays production by laser-electron Compton scattering

International Nuclear Information System (INIS)

Fedala, Y.

2008-10-01

The main goal of this thesis is the study and design of a high finesse Fabry Perot cavity to amplify a laser beam in order to achieve power gains ranging from 10 4 to 10 5 . This cavity is dedicated to the production of intense and monochromatic X-ray for medical applications (medical RADIOTHOMX ring) and gamma rays for a Compton based polarized positron source by Compton scattering of a high power laser beam and electron beam. To increase the brightness of the Compton interaction at the collision points, it is essential to have not only a high power laser beam but also very small laser beam radii at the interaction points. To achieve such performances, 2 scenarios are possible: a concentric 2 mirrors cavity which is mechanically unstable or a 4 mirrors cavity more complex but more stable. We tested numerically mechanical stability and stability of Eigen modes polarization of various planar and non-planar geometries of 4 mirrors cavities. Experimentally, we have developed a four mirrors tetrahedral 'bow-tie' cavity; radii of the order of 20 microns were made. The Eigen modes of such a cavity, in both planar and non planar geometries, were measured and compared with the numerical results. A good agreement was observed. In a second time, the impact of Compton interaction on the transverse dynamics, in the case of the polarized positrons source, and the longitudinal dynamic, in the case of the medical ring of the electron beam was studied. Compton scattering causes energy loss and induces an additional dispersion of energy in electron beam. For the polarized positrons source, 10 collision points are planned. The transport line has been determined and the modelling of the Compton interaction effect with a simple matrix calculation was made. For the medical ring, Compton scattering causes bunch lengthening and the increase of energy dispersion which are to influence the produced X-ray flux. A study of the longitudinal dynamics of the electron beam in the ring was

Design and simulation of the surface shape control system for membrane mirror

Science.gov (United States)

Zhang, Gengsheng; Tang, Minxue

2009-11-01

The surface shape control is one of the key technologies for the manufacture of membrane mirror. This paper presents a design of membrane mirror's surface shape control system on the basis of fuzzy logic control. The system contains such function modules as surface shape design, surface shape control, surface shape analysis, and etc. The system functions are realized by using hybrid programming technology of Visual C# and MATLAB. The finite element method is adopted to simulate the surface shape control of membrane mirror. The finite element analysis model is established through ANSYS Parametric Design Language (APDL). ANSYS software kernel is called by the system in background running mode when doing the simulation. The controller is designed by means of controlling the sag of the mirror's central crosssection. The surface shape of the membrane mirror and its optical aberration are obtained by applying Zernike polynomial fitting. The analysis of surface shape control and the simulation of disturbance response are performed for a membrane mirror with 300mm aperture and F/2.7. The result of the simulation shows that by using the designed control system, the RMS wavefront error of the mirror can reach to 142λ (λ=632.8nm), which is consistent to the surface accuracy of the membrane mirror obtained by the large deformation theory of membrane under the same condition.

Calibration of the mirror system in the HERA-B RICH

OpenAIRE

Starič, Marko; Križan, Peter

2007-01-01

The mirror system of the HERA-B RICH consists of two spherical and two planar mirrors, composed of altogether 116 mirror segments. Analysis of displacements of the \\v{C}erenkov ring center relative to the charged particle track, for given spherical-planar segment pairs, leads to accurate information regarding the orientation of individual mirror segments. The method is described and the effect of applying the required corrections on the \\v{C}erenkov angle resolution of the HERA-B RICH is disc...

DESIGN OF MIRRORS AND APODIZATION FUNCTIONS IN PHASE-INDUCED AMPLITUDE APODIZATION SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Cady, Eric, E-mail: eric.j.cady@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109 (United States)

2012-08-01

Phase-induced amplitude apodization (PIAA) coronagraphs are a promising technology for imaging exoplanets, with the potential to detect Earth-like planets around Sun-like stars. A PIAA system nominally consists of a pair of mirrors that reshape incident light without attenuation, coupled with one or more apodizers to mitigate diffraction effects or provide additional beam shaping to produce a desired output profile. We present a set of equations that allow apodizers to be chosen for any given pair of mirrors, or conversely mirror shapes chosen for given apodizers, to produce an arbitrary amplitude profile at the output of the system. We show how classical PIAA systems may be designed by this method and present the design of a novel four-mirror system with higher throughput than a standard two-mirror system. We also discuss the limitations due to diffraction and the design steps that may be taken to mitigate them.

The mirror system and its role in social cognition.

Science.gov (United States)

Rizzolatti, Giacomo; Fabbri-Destro, Maddalena

2008-04-01

Experiments in monkeys have shown that coding the goal of the motor acts is a fundamental property of the cortical motor system. In area F5, goal-coding motor neurons are also activated by observing motor acts done by others (the 'classical' mirror mechanism); in area F2 and area F1, some motor neurons are activated by the mere observation of goal-directed movements of a cursor displayed on a computer screen (a 'mirror-like' mechanism). Experiments in humans and monkeys have shown that the mirror mechanism enables the observer to understand the intention behind an observed motor act, in addition to the goal of it. Growing evidence shows that a deficit in the mirror mechanism underlies some aspects of autism.

Delayed coherent quantum feedback from a scattering theory and a matrix product state perspective

Science.gov (United States)

Guimond, P.-O.; Pletyukhov, M.; Pichler, H.; Zoller, P.

2017-12-01

We study the scattering of photons propagating in a semi-infinite waveguide terminated by a mirror and interacting with a quantum emitter. This paradigm constitutes an example of coherent quantum feedback, where light emitted towards the mirror gets redirected back to the emitter. We derive an analytical solution for the scattering of two-photon states, which is based on an exact resummation of the perturbative expansion of the scattering matrix, in a regime where the time delay of the coherent feedback is comparable to the timescale of the quantum emitter’s dynamics. We compare the results with numerical simulations based on matrix product state techniques simulating the full dynamics of the system, and extend the study to the scattering of coherent states beyond the low-power limit.

A primary mirror metrology system for the GMT

Science.gov (United States)

Rakich, A.

2016-07-01

The Giant Magellan Telescope (GMT)1 is a 25 m "doubly segmented" telescope composed of seven 8.4 m "unit Gregorian telescopes", on a common mount. Each primary and secondary mirror segment will ideally lie on the geometrical surface of the corresponding rotationally symmetrical full aperture optical element. Therefore, each primary and conjugated secondary mirror segment will feed a common instrument interface, their focal planes co-aligned and cophased. First light with a subset of four unit telescopes is currently scheduled for 2022. The project is currently considering an important aspect of the assembly, integration and verification (AIV) phase of the project. This paper will discuss a dedicated system to directly characterize the on-sky performance of the M1 segments, independently of the M2 subsystem. A Primary Mirror Metrology System (PMS) is proposed. The main purpose of this system will be to he4lp determine the rotation axis of an instrument rotator (the Gregorian Instrument Rotator or GIR in this case) and then to characterize the deflections and deformations of the M1 segments with respect to this axis as a function of gravity and temperature. The metrology system will incorporate a small (180 mm diameter largest element) prime focus corrector (PFC) that simultaneously feeds a risk reduction during AIV; it allows an on-sky characterization of the primary mirror segments and cells, without the complications of other optical elements. The PMS enables a very useful alignment strategy that constrains each primary mirror segments' optical axes to follow the GIR axis to within a few arc seconds. An additional attractive feature of the incorporation of the PMS into the AIV plan, is that it allows first on-sky telescope operations to occur with a system of considerably less optical and control complexity than the final doubly segmented Gregorian telescope configuration. This paper first discusses the strategic rationale for a PMS. Next the system itself is

Machining and metrology systems for free-form laser printer mirrors

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

optical systems were designed and manufactured for the individual laser wavelength to be ... The design objective in utilizing a free-form mirror has resulted in a corresponding ... Since mass production of these free-form mirrors is required, the ...

Sign language processing and the mirror neuron system.

Science.gov (United States)

Corina, David P; Knapp, Heather

2006-05-01

In this paper we review evidence for frontal and parietal lobe involvement in sign language comprehension and production, and evaluate the extent to which these data can be interpreted within the context of a mirror neuron system for human action observation and execution. We present data from three literatures--aphasia, cortical stimulation, and functional neuroimaging. Generally, we find support for the idea that sign language comprehension and production can be viewed in the context of a broadly-construed frontal-parietal human action observation/execution system. However, sign language data cannot be fully accounted for under a strict interpretation of the mirror neuron system. Additionally, we raise a number of issues concerning the lack of specificity in current accounts of the human action observation/execution system.

Modulation of the mirror system by social relevance.

Science.gov (United States)

Kilner, James M; Marchant, Jennifer L; Frith, Chris D

2006-09-01

When we observe the actions of others, certain areas of the brain are activated in a similar manner as to when we perform the same actions ourselves. This 'mirror system' includes areas in the ventral premotor cortex and the inferior parietal lobule. Experimental studies suggest that action observation automatically elicits activity in the observer, which precisely mirrors the activity observed. In this case we would expect this activity to be independent of observer's viewpoint. Here we use whole-head magnetoencephalography (MEG) to record cortical activity of human subjects whilst they watched a series of videos of an actor making a movement recorded from different viewpoints. We show that one cortical response to action observation (oscillatory activity in the 7-12 Hz frequency range) is modulated by the relationship between the observer and the actor. We suggest that this modulation reflects a mechanism that filters information into the 'mirror system', allowing only socially relevant information to pass.

Are mirror neurons the basis of speech perception? Evidence from five cases with damage to the purported human mirror system

Science.gov (United States)

Rogalsky, Corianne; Love, Tracy; Driscoll, David; Anderson, Steven W.; Hickok, Gregory

2013-01-01

The discovery of mirror neurons in macaque has led to a resurrection of motor theories of speech perception. Although the majority of lesion and functional imaging studies have associated perception with the temporal lobes, it has also been proposed that the ‘human mirror system’, which prominently includes Broca’s area, is the neurophysiological substrate of speech perception. Although numerous studies have demonstrated a tight link between sensory and motor speech processes, few have directly assessed the critical prediction of mirror neuron theories of speech perception, namely that damage to the human mirror system should cause severe deficits in speech perception. The present study measured speech perception abilities of patients with lesions involving motor regions in the left posterior frontal lobe and/or inferior parietal lobule (i.e., the proposed human ‘mirror system’). Performance was at or near ceiling in patients with fronto-parietal lesions. It is only when the lesion encroaches on auditory regions in the temporal lobe that perceptual deficits are evident. This suggests that ‘mirror system’ damage does not disrupt speech perception, but rather that auditory systems are the primary substrate for speech perception. PMID:21207313

Interface morphology of Mo/Si multilayer systems with varying Mo layer thickness studied by EUV diffuse scattering.

Science.gov (United States)

Haase, Anton; Soltwisch, Victor; Braun, Stefan; Laubis, Christian; Scholze, Frank

2017-06-26

We investigate the influence of the Mo-layer thickness on the EUV reflectance of Mo/Si mirrors with a set of unpolished and interface-polished Mo/Si/C multilayer mirrors. The Mo-layer thickness is varied in the range from 1.7 nm to 3.05 nm. We use a novel combination of specular and diffuse intensity measurements to determine the interface roughness throughout the multilayer stack and do not rely on scanning probe measurements at the surface only. The combination of EUV and X-ray reflectivity measurements and near-normal incidence EUV diffuse scattering allows to reconstruct the Mo layer thicknesses and to determine the interface roughness power spectral density. The data analysis is conducted by applying a matrix method for the specular reflection and the distorted-wave Born approximation for diffuse scattering. We introduce the Markov-chain Monte Carlo method into the field in order to determine the respective confidence intervals for all reconstructed parameters. We unambiguously detect a threshold thickness for Mo in both sample sets where the specular reflectance goes through a local minimum correlated with a distinct increase in diffuse scatter. We attribute that to the known appearance of an amorphous-to-crystallization transition at a certain thickness threshold which is altered in our sample system by the polishing.

Mirror Confinement Systems: project summaries

International Nuclear Information System (INIS)

1980-07-01

This report contains descriptions of the projects supported by the Mirror Confinement Systems (MCS) Division of the Office of Fusion Energy. The individual project summaries were prepared by the principal investigators, in collaboration with MCS staff office, and include objectives and milestones for each project. In addition to project summaries, statements of Division objectives and budget summaries are also provided

[The mirror neuron system in motor and sensory rehabilitation].

Science.gov (United States)

Oouchida, Yutaka; Izumi, Shinichi

2014-06-01

The discovery of the mirror neuron system has dramatically changed the study of motor control in neuroscience. The mirror neuron system provides a conceptual framework covering the aspects of motor as well as sensory functions in motor control. Previous studies of motor control can be classified as studies of motor or sensory functions, and these two classes of studies appear to have advanced independently. In rehabilitation requiring motor learning, such as relearning movement after limb paresis, however, sensory information of feedback for motor output as well as motor command are essential. During rehabilitation from chronic pain, motor exercise is one of the most effective treatments for pain caused by dysfunction in the sensory system. In rehabilitation where total intervention unifying the motor and sensory aspects of motor control is important, learning through imitation, which is associated with the mirror neuron system can be effective and suitable. In this paper, we introduce the clinical applications of imitated movement in rehabilitation from motor impairment after brain damage and phantom limb pain after limb amputation.

Fabrication of nested elliptical KB mirrors using profile coating for synchrotron radiation X-ray focusing

International Nuclear Information System (INIS)

Liu Chian; Ice, G.E.; Liu, W.; Assoufid, L.; Qian, J.; Shi, B.; Khachatryan, R.; Wieczorek, M.; Zschack, P.; Tischler, J.Z.

2012-01-01

This paper describes fabrication methods used to demonstrate the advantages of nested or Montel optics for micro/nanofocusing of synchrotron X-ray beams. A standard Kirkpatrick-Baez (KB) mirror system uses two separated elliptical mirrors at glancing angles to the X-ray beam and sequentially arranged at 90° to each other to focus X-rays successively in the vertical and horizontal directions. A nested KB mirror system has the two mirrors positioned perpendicular and side-by-side to each other. Compared to a standard KB mirror system, Montel optics can focus a larger divergence and the mirrors can have a shorter focal length. As a result, nested mirrors can be fabricated with improved demagnification factor and ultimately smaller focal spot, than with a standard KB arrangement. The nested system is also more compact with an increased working distance, and is more stable, with reduced complexity of mirror stages. However, although Montel optics is commercially available for laboratory X-ray sources, due to technical difficulties they have not been used to microfocus synchrotron radiation X-rays, where ultra-precise mirror surfaces are essential. The main challenge in adapting nested optics for synchrotron microfocusing is to fabricate mirrors with a precise elliptical surface profile at the very edge where the two mirrors meet and where X-rays scatter. For example, in our application to achieve a sub-micron focus with high efficiency, a surface figure root-mean-square (rms) error on the order of 1 nm is required in the useable area along the X-ray footprint with a ∼0.1 mm-diameter cross section. In this paper we describe promising ways to fabricate precise nested KB mirrors using our profile coating technique and inexpensive flat Si substrates.

Mirror Objects in the Solar System?

International Nuclear Information System (INIS)

Silagadze, Z.K.

2002-01-01

This talk was given at the Tunguska-2001 international conference but it is not about the Tunguska event. Instead we tried to give some flavor of mirror matter, which is predicted to exist if parity is an unbroken symmetry of nature, to non-experts. The possible connection of the mirror matter ideas to the Tunguska phenomenon was indicated by Foot and Gninenko some time ago and was elaborated by Foot in the separate talk at this conference. If the mirror world interpretation of the Tunguska like events is indeed correct then the most fascinating (but very speculative) possibility is that some well known celestial bodies with strange properties are in fact made mostly from mirror matter, and so maybe the mirror world was discovered long ago and we just have not suspected this. (author)

Magnet system for a thermal barrier Tandem Mirror Reactor

International Nuclear Information System (INIS)

Kim, N.S.; Conn, R.W.

1981-01-01

The magnet system for a thermal barrier D-D tandem mirror reactor has been studied as part of the UCLA tandem mirror reactor design study SATYR. Three main considerations in designing the SATYR magnet system are to obtain the desired field strength variation throughout the system, to have proper space for plasma and neutron shielding, and to satisfy the MHD stability to achieve maximum central cell /beta/. Due to the importance and the complexity, the 'internal' field reversal magnet is the main concern in the entire magnet system for SATYR. Two different magnet designs, a non-uniform current density solenoid and a higher-order solenoid, are discussed. Coil levitation for the internal field reversal magnet has been analyzed

Control system for several rotating mirror camera synchronization operation

Science.gov (United States)

Liu, Ningwen; Wu, Yunfeng; Tan, Xianxiang; Lai, Guoji

1997-05-01

This paper introduces a single chip microcomputer control system for synchronization operation of several rotating mirror high-speed cameras. The system consists of four parts: the microcomputer control unit (including the synchronization part and precise measurement part and the time delay part), the shutter control unit, the motor driving unit and the high voltage pulse generator unit. The control system has been used to control the synchronization working process of the GSI cameras (driven by a motor) and FJZ-250 rotating mirror cameras (driven by a gas driven turbine). We have obtained the films of the same objective from different directions in different speed or in same speed.

Gender differences in the mu rhythm of the human mirror-neuron system.

Science.gov (United States)

Cheng, Yawei; Lee, Po-Lei; Yang, Chia-Yen; Lin, Ching-Po; Hung, Daisy; Decety, Jean

2008-05-07

Psychologically, females are usually thought to be superior in interpersonal sensitivity than males. The human mirror-neuron system is considered to provide the basic mechanism for social cognition. However, whether the human mirror-neuron system exhibits gender differences is not yet clear. We measured the electroencephalographic mu rhythm, as a reliable indicator of the human mirror-neuron system activity, when female (N = 20) and male (N = 20) participants watched either hand actions or a moving dot. The display of the hand actions included androgynous, male, and female characteristics. The results demonstrate that females displayed significantly stronger mu suppression than males when watching hand actions. Instead, mu suppression was similar across genders when participants observed the moving dot and between the perceived sex differences (same-sex vs. opposite-sex). In addition, the mu suppressions during the observation of hand actions positively correlated with the personal distress subscale of the interpersonal reactivity index and negatively correlated with the systemizing quotient. The present findings indirectly lend support to the extreme male brain theory put forward by Baron-Cohen (2005), and may cast some light on the mirror-neuron dysfunction in autism spectrum disorders. The mu rhythm in the human mirror-neuron system can be a potential biomarker of empathic mimicry.

Quantum noise in the mirror-field system: A field theoretic approach

Energy Technology Data Exchange (ETDEWEB)

Hsiang, Jen-Tsung, E-mail: cosmology@gmail.com [Department of Physics, National Dong-Hwa University, Hua-lien, Taiwan, ROC (China); Wu, Tai-Hung [Department of Physics, National Dong-Hwa University, Hua-lien, Taiwan, ROC (China); Lee, Da-Shin, E-mail: dslee@mail.ndhu.edu.tw [Department of Physics, National Dong-Hwa University, Hua-lien, Taiwan, ROC (China); King, Sun-Kun [Institutes of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan, ROC (China); Wu, Chun-Hsien [Department of Physics, Soochow University, Taipei, Taiwan, ROC (China)

2013-02-15

We revisit the quantum noise problem in the mirror-field system by a field-theoretic approach. Here a perfectly reflecting mirror is illuminated by a single-mode coherent state of the massless scalar field. The associated radiation pressure is described by a surface integral of the stress-tensor of the field. The read-out field is measured by a monopole detector, from which the effective distance between the detector and mirror can be obtained. In the slow-motion limit of the mirror, this field-theoretic approach allows to identify various sources of quantum noise that all in all leads to uncertainty of the read-out measurement. In addition to well-known sources from shot noise and radiation pressure fluctuations, a new source of noise is found from field fluctuations modified by the mirror's displacement. Correlation between different sources of noise can be established in the read-out measurement as the consequence of interference between the incident field and the field reflected off the mirror. In the case of negative correlation, we found that the uncertainty can be lowered than the value predicted by the standard quantum limit. Since the particle-number approach is often used in quantum optics, we compared results obtained by both approaches and examine its validity. We also derive a Langevin equation that describes the stochastic dynamics of the mirror. The underlying fluctuation-dissipation relation is briefly mentioned. Finally we discuss the backreaction induced by the radiation pressure. It will alter the mean displacement of the mirror, but we argue this backreaction can be ignored for a slowly moving mirror. - Highlights: Black-Right-Pointing-Pointer The quantum noise problem in the mirror-field system is re-visited by a field-theoretic approach. Black-Right-Pointing-Pointer Other than the shot noise and radiation pressure noise, we show there are new sources of noise and correlation between them. Black-Right-Pointing-Pointer The noise

NASA's OCA Mirroring System: An Application of Multiagent Systems in Mission Control

Science.gov (United States)

Sierhuis, Maarten; Clancey, William J.; vanHoof, Ron J. J.; Seah, Chin H.; Scott, Michael S.; Nado, Robert A.; Blumenberg, Susan F.; Shafto, Michael G.; Anderson, Brian L.; Bruins, Anthony C.;

Studying the Behaviour of Model of Mirror Neuron System in Case of Autism

OpenAIRE

Anirban, Shikha; Hanif Ali, Mohammad

2012-01-01

Several experiment done by the researchers conducted that autism is caused by the dysfunctional mirror neuron system and the dysfunctions of mirror neuron system is proportional to the symptom severity of autism. In the present work those experiments were studied as well as studying a model of mirror neuron system called MNS2 developed by a research group. This research examined the behavior of the model in case of autism and compared the result with those studies conducting dysfunctions of m...

Performance Characteristics of Mirror Servers on the Internet

National Research Council Canada - National Science Library

Meyers, Andy

1998-01-01

... retrieved. In this paper we present findings from measuring 9 clients scattered throughout the United States retrieving over 490,000 documents from 45 production web servers which mirror three different sites...

Design and Optimization of Thermophotovoltaic System Cavity with Mirrors

Directory of Open Access Journals (Sweden)

Tian Zhou

2016-09-01

Full Text Available Thermophotovoltaic (TPV systems can convert radiant energy into electrical power. Here we explore the design of the TPV system cavity, which houses the emitter and the photovoltaic (PV cells. Mirrors are utilized in the cavity to modify the spatial and spectral distribution within. After discussing the basic concentric tubular design, two novel cavity configurations are put forward and parametrically studied. The investigated variables include the shape, number, and placement of the mirrors. The optimization objectives are the optimized efficiency and the extended range of application of the TPV system. Through numerical simulations, the relationship between the design parameters and the objectives are revealed. The results show that careful design of the cavity configuration can markedly enhance the performance of the TPV system.

Can syntax appear in a mirror (system)?

Science.gov (United States)

Tettamanti, Marco; Moro, Andrea

2012-07-01

Converging evidence indicates that the processing of some aspects related to the phonetic and the semantic components of language is tightly associated with both the perceptual and the motor neural systems. It has been suggested that mirror neurons contribute to language understanding by virtue of a neurophysiological response matching perceptual linguistic information onto corresponding motor plans. This proposal has sometimes been extended to advocate that the language competence as a whole, including syntax, may be ascribed to this kind of perceptuo-motor mappings. This position paper examines what kinds of empirical and theoretical challenges such general mirror neuron language accounts need to face in order to proof their validity--challenges that we think have not been adequately addressed yet. We highlight that the most important limitation is constituted by the fact that some core defining properties of human language, at the phonetic, semantic, and especially at the syntactic level, are not transparent to the bodily senses and thus they cannot be the direct source of mirror neuron perceptuo-motor matching. Copyright © 2011 Elsevier Srl. All rights reserved.

Sensorimotor cortex as a critical component of an 'extended' mirror neuron system: Does it solve the development, correspondence, and control problems in mirroring?

Directory of Open Access Journals (Sweden)

Pineda Jaime A

2008-10-01

Full Text Available Abstract A core assumption of how humans understand and infer the intentions and beliefs of others is the existence of a functional self-other distinction. At least two neural systems have been proposed to manage such a critical distinction. One system, part of the classic motor system, is specialized for the preparation and execution of motor actions that are self realized and voluntary, while the other appears primarily involved in capturing and understanding the actions of non-self or others. The latter system, of which the mirror neuron system is part, is the canonical action 'resonance' system in the brain that has evolved to share many of the same circuits involved in motor control. Mirroring or 'shared circuit systems' are assumed to be involved in resonating, imitating, and/or simulating the actions of others. A number of researchers have proposed that shared representations of motor actions may form a foundational cornerstone for higher order social processes, such as motor learning, action understanding, imitation, perspective taking, understanding facial emotions, and empathy. However, mirroring systems that evolve from the classic motor system present at least three problems: a development, a correspondence, and a control problem. Developmentally, the question is how does a mirroring system arise? How do humans acquire the ability to simulate through mapping observed onto executed actions? Are mirror neurons innate and therefore genetically programmed? To what extent is learning necessary? In terms of the correspondence problem, the question is how does the observer agent know what the observed agent's resonance activation pattern is? How does the matching of motor activation patterns occur? Finally, in terms of the control problem, the issue is how to efficiently control a mirroring system when it is turned on automatically through observation? Or, as others have stated the problem more succinctly: "Why don't we imitate all the time

Sensorimotor cortex as a critical component of an 'extended' mirror neuron system: Does it solve the development, correspondence, and control problems in mirroring?

Science.gov (United States)

Pineda, Jaime A

2008-01-01

A core assumption of how humans understand and infer the intentions and beliefs of others is the existence of a functional self-other distinction. At least two neural systems have been proposed to manage such a critical distinction. One system, part of the classic motor system, is specialized for the preparation and execution of motor actions that are self realized and voluntary, while the other appears primarily involved in capturing and understanding the actions of non-self or others. The latter system, of which the mirror neuron system is part, is the canonical action 'resonance' system in the brain that has evolved to share many of the same circuits involved in motor control. Mirroring or 'shared circuit systems' are assumed to be involved in resonating, imitating, and/or simulating the actions of others. A number of researchers have proposed that shared representations of motor actions may form a foundational cornerstone for higher order social processes, such as motor learning, action understanding, imitation, perspective taking, understanding facial emotions, and empathy. However, mirroring systems that evolve from the classic motor system present at least three problems: a development, a correspondence, and a control problem. Developmentally, the question is how does a mirroring system arise? How do humans acquire the ability to simulate through mapping observed onto executed actions? Are mirror neurons innate and therefore genetically programmed? To what extent is learning necessary? In terms of the correspondence problem, the question is how does the observer agent know what the observed agent's resonance activation pattern is? How does the matching of motor activation patterns occur? Finally, in terms of the control problem, the issue is how to efficiently control a mirroring system when it is turned on automatically through observation? Or, as others have stated the problem more succinctly: "Why don't we imitate all the time?" In this review, we argue

Language comprehension warps the mirror neuron system

Directory of Open Access Journals (Sweden)

Noah eZarr

2013-12-01

Full Text Available Is the mirror neuron system (MNS used in language understanding? According to embodied accounts of language comprehension, understanding sentences describing actions makes use of neural mechanisms of action control, including the MNS. Consequently, repeatedly comprehending sentences describing similar actions should induce adaptation of the MNS thereby warping its use in other cognitive processes such as action recognition and prediction. To test this prediction, participants read blocks of multiple sentences where each sentence in the block described transfer of objects in a direction away or toward the reader. Following each block, adaptation was measured by having participants predict the end-point of videotaped actions. The adapting sentences disrupted prediction of actions in the same direction, but a only for videos of biological motion, and b only when the effector implied by the language (e.g., the hand matched the videos. These findings are signatures of the mirror neuron system.

Quantizing the electromagnetic field near two-sided semitransparent mirrors

Science.gov (United States)

Furtak-Wells, Nicholas; Clark, Lewis A.; Purdy, Robert; Beige, Almut

2018-04-01

This paper models light scattering through flat surfaces with finite transmission, reflection, and absorption rates, with wave packets approaching the mirror from both sides. While using the same notion of photons as in free space, our model also accounts for the presence of mirror images and the possible exchange of energy between the electromagnetic field and the mirror surface. To test our model, we derive the spontaneous decay rate and the level shift of an atom in front of a semitransparent mirror as a function of its transmission and reflection rates. When considering limiting cases and using standard approximations, our approach reproduces well-known results but it also paves the way for the modeling of more complex scenarios.

Mirror fusion test facility plasma diagnostics system

International Nuclear Information System (INIS)

Thomas, S.R. Jr.; Coffield, F.E.; Davis, G.E.; Felker, B.

1979-01-01

During the past 25 years, experiments with several magnetic mirror machines were performed as part of the Magnetic Fusion Energy (MFE) Program at LLL. The latest MFE experiment, the Mirror Fusion Test Facility (MFTF), builds on the advances of earlier machines in initiating, stabilizing, heating, and sustaining plasmas formed with deuterium. The goals of this machine are to increase ion and electron temperatures and show a corresponding increase in containment time, to test theoretical scaling laws of plasma instabilities with increased physical dimensions, and to sustain high-beta plasmas for times that are long compared to the energy containment time. This paper describes the diagnostic system being developed to characterize these plasma parameters

Optimal micro-mirror tilt angle and sync mark design for digital micro-mirror device based collinear holographic data storage system.

Science.gov (United States)

Liu, Jinpeng; Horimai, Hideyoshi; Lin, Xiao; Liu, Jinyan; Huang, Yong; Tan, Xiaodi

2017-06-01

The collinear holographic data storage system (CHDSS) is a very promising storage system due to its large storage capacities and high transfer rates in the era of big data. The digital micro-mirror device (DMD) as a spatial light modulator is the key device of the CHDSS due to its high speed, high precision, and broadband working range. To improve the system stability and performance, an optimal micro-mirror tilt angle was theoretically calculated and experimentally confirmed by analyzing the relationship between the tilt angle of the micro-mirror on the DMD and the power profiles of diffraction patterns of the DMD at the Fourier plane. In addition, we proposed a novel chess board sync mark design in the data page to reduce the system bit error rate in circumstances of reduced aperture required to decrease noise and median exposure amount. It will provide practical guidance for future DMD based CHDSS development.

Optical systems for synchrotron radiation. Lecture 2. Mirror systems

International Nuclear Information System (INIS)

Howells, M.R.

1986-02-01

The process of reflection of VUV and x-radiation is summarized. The functions of mirrors in synchrotron beamlines are described, which include deflection, filtration, power absorption, formation of a real image, focusing, and collimation. Fabrication of optical surfaces for synchrotron radiation beamlines are described, and include polishing of a near spherical surface as well as bending a cylindrical surface to toroidal shape. The imperfections present in mirrors, aberrations and surface figure inaccuracy, are discussed. Calculation of the thermal load of a mirror in a synchrotron radiation beam and the cooling of the mirror are covered briefly. 50 refs., 7 figs

Mirror theory applied to toroidal systems

International Nuclear Information System (INIS)

Cohen, R.H.

1987-01-01

Central features of a mirror plasma are strong departures from Maxwellian distribution functions, ambipolar potentials and densities which vary along a field line, and losses, and the mirror field itself. To examine these features, mirror theorists have developed analytical and numerical techniques to solve the Fokker-Planck equation, evaluate the potentials consistent with the resulting distribution functions, and assess the microstability of these distributions. Various combinations of mirror-plasma fetures are present and important in toroidal plasmas as well, particularly in the edge region and in plasmas with strong r.f. heating. In this paper we survey problems in toroidal plasmas where mirror theory and computational techniques are applicable, and discuss in more detail three specific examples: calculation of the toroidal generalization of the Spitzer-Haerm distribution function (from which trapped-particle effects on current drive can be calculated), evaluation of the nonuniform potential and density set up by pulsed electron-cyclotron heating, and calculation of steady-state distribution functions in the presence of strong r.f. heating and collisions. 37 refs., 3 figs

Mirror theory applied to toroidal systems

International Nuclear Information System (INIS)

Cohen, R.H.

1987-01-01

Central features of a mirror plasma are strong departures from Maxwellian distribution functions, ambipolar potentials and densities which vary along a field line, end losses, and the mirror field itself. To examine these features, mirror theorists have developed analytical and numerical techniques to solve the Fokker-Planck equation, evaluate the potentials consistent with the resulting distribution functions, and assess the microstability of these distributions. Various combinations of mirror-plasma features are present and important in toroidal plasmas as well, particularly in the edge region and in plasmas with strong rf heating. In this paper we survey problems in toroidal plasmas where mirror theory and computational techniques are applicable, and discuss in more detail three specific examples: calculation of the toroidal generalization of the Spitzer-Haerm distribution function (from which trapped-particle effects on current drive can be calculated), evaluation of the nonuniform potential and density set up by pulsed electron-cyclotron heating, and calculation of steady-state distribution functions in the presence of strong rf heating and collisions. 37 refs

Studying the Behaviour of Model of Mirror Neuron System in Case of Autism

Directory of Open Access Journals (Sweden)

Shikha Anirban

2012-04-01

Full Text Available Several experiment done by the researchers conducted that autism is caused by the dysfunctional mirror neuron system and the dysfunctions of mirror neuron system is proportional to the symptom severity of autism. In the present work those experiments were studied as well as studying a model of mirror neuron system called MNS2 developed by a research group. This research examined the behavior of the model in case of autism and compared the result with those studies conducting dysfunctions of mirror neuron system in autism. To perform this, a neural network employing the model was developed which recognized the three types of grasping (faster, normal and slower. The network was implemented with back propagation through time learning algorithm. The whole grasping process was divided into 30 time steps and different hand and object states at each time step was used as the input of the network. Normally the network successfully recognized all of the three types of grasps. The network required more times as the number of inactive neurons increased. And in case of maximum inactive neurons of the mirror neuron system the network became unable to recognize the types of grasp. As the time to recognize the types of grasp is proportional to the number of inactive neurons, the experiment result supports the hypothesis that dysfunctions of MNS is proportional to the symptom severity of autism. Keywords— Autism, MNS, mirror neuron, neural network, BPTT

[Motion control of moving mirror based on fixed-mirror adjustment in FTIR spectrometer].

Science.gov (United States)

Li, Zhong-bing; Xu, Xian-ze; Le, Yi; Xu, Feng-qiu; Li, Jun-wei

2012-08-01

The performance of the uniform motion of the moving mirror, which is the only constant motion part in FTIR spectrometer, and the performance of the alignment of the fixed mirror play a key role in FTIR spectrometer, and affect the interference effect and the quality of the spectrogram and may restrict the precision and resolution of the instrument directly. The present article focuses on the research on the uniform motion of the moving mirror and the alignment of the fixed mirror. In order to improve the FTIR spectrometer, the maglev support system was designed for the moving mirror and the phase detection technology was adopted to adjust the tilt angle between the moving mirror and the fixed mirror. This paper also introduces an improved fuzzy PID control algorithm to get the accurate speed of the moving mirror and realize the control strategy from both hardware design and algorithm. The results show that the development of the moving mirror motion control system gets sufficient accuracy and real-time, which can ensure the uniform motion of the moving mirror and the alignment of the fixed mirror.

Reflecting on the mirror neuron system in autism: a systematic review of current theories.

Science.gov (United States)

Hamilton, Antonia F de C

2013-01-01

There is much interest in the claim that dysfunction of the mirror neuron system in individuals with autism spectrum condition causes difficulties in social interaction and communication. This paper systematically reviews all published studies using neuroscience methods (EEG/MEG/TMS/eyetracking/EMG/fMRI) to examine the integrity of the mirror system in autism. 25 suitable papers are reviewed. The review shows that current data are very mixed and that studies using weakly localised measures of the integrity of the mirror system are hard to interpret. The only well localised measure of mirror system function is fMRI. In fMRI studies, those using emotional stimuli have reported group differences, but studies using non-emotional hand action stimuli do not. Overall, there is little evidence for a global dysfunction of the mirror system in autism. Current data can be better understood under an alternative model in which social top-down response modulation is abnormal in autism. The implications of this model and future research directions are discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Timecourse of mirror and counter-mirror effects measured with transcranial magnetic stimulation.

Science.gov (United States)

Cavallo, Andrea; Heyes, Cecilia; Becchio, Cristina; Bird, Geoffrey; Catmur, Caroline

2014-08-01

The human mirror system has been the subject of much research over the past two decades, but little is known about the timecourse of mirror responses. In addition, it is unclear whether mirror and counter-mirror effects follow the same timecourse. We used single-pulse transcranial magnetic stimulation to investigate the timecourse of mirror and counter-mirror responses in the human brain. Experiment 1 demonstrated that mirror responses can be measured from around 200 ms after observed action onset. Experiment 2 demonstrated significant effects of counter-mirror sensorimotor training at all timepoints at which a mirror response was found in Experiment 1 (i.e. from 200 ms onward), indicating that mirror and counter-mirror responses follow the same timecourse. By suggesting similarly direct routes for mirror and counter-mirror responses, these results support the associative account of mirror neuron origins whereby mirror responses arise as a result of correlated sensorimotor experience during development. More generally, they contribute to theorizing regarding mirror neuron function by providing some constraints on how quickly mirror responses can influence social cognition. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Mirror fusion propulsion system - A performance comparison with alternate propulsion systems for the manned Mars mission

International Nuclear Information System (INIS)

Deveny, M.; Carpenter, S.; O'connell, T.; Schulze, N.

1993-06-01

The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a mirror fusion space propulsion system. The proposed magnetic mirror fusion reactor, known as the Mirror Fusion Propulsion System (MFPS), is described. The description is an overview of a design study that was conducted to convert a mirror reactor experiment at Lawrence Livermore National Lab (LLNL) into a viable space propulsion system. Design principles geared towards minimizing mass and maximizing power available for thrust are identified and applied to the LLNL reactor design, resulting in the MFPS. The MFPS' design evolution, reactor and fuel choices, and system configuration are described. Results of the performance comparison shows that the MFPS minimizes flight time to 60 to 90 days for flights to Mars while allowing continuous return-home capability while at Mars. Total MFPS IMLEO including propellant and payloads is kept to about 1,000 metric tons. 50 refs

High-concentration mirror-based Kohler integrating system for tandem solar cells

Science.gov (United States)

Winston, R.; Benitez, P.; Cvetkovic, A.

2006-06-01

A novel two-mirror high concentration nonimaging optic has been designed that shares the advantages of present two mirror aplanatic imaging concentrators but also overcomes their main limitation of trade-off between acceptance angle and irradiance uniformity. A system concept has been defined, and a first prototype in under development.

Observing complex action sequences: The role of the fronto-parietal mirror neuron system.

Science.gov (United States)

Molnar-Szakacs, Istvan; Kaplan, Jonas; Greenfield, Patricia M; Iacoboni, Marco

2006-11-15

A fronto-parietal mirror neuron network in the human brain supports the ability to represent and understand observed actions allowing us to successfully interact with others and our environment. Using functional magnetic resonance imaging (fMRI), we wanted to investigate the response of this network in adults during observation of hierarchically organized action sequences of varying complexity that emerge at different developmental stages. We hypothesized that fronto-parietal systems may play a role in coding the hierarchical structure of object-directed actions. The observation of all action sequences recruited a common bilateral network including the fronto-parietal mirror neuron system and occipito-temporal visual motion areas. Activity in mirror neuron areas varied according to the motoric complexity of the observed actions, but not according to the developmental sequence of action structures, possibly due to the fact that our subjects were all adults. These results suggest that the mirror neuron system provides a fairly accurate simulation process of observed actions, mimicking internally the level of motoric complexity. We also discuss the results in terms of the links between mirror neurons, language development and evolution.

Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems

CERN Document Server

Wu, Zhizheng; Ben Amara, Foued

2013-01-01

Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems presents a novel design of wavefront correctors based on magnetic fluid deformable mirrors (MFDM) as well as corresponding control algorithms. The presented wavefront correctors are characterized by their linear, dynamic response. Various mirror surface shape control algorithms are presented along with experimental evaluations of the performance of the resulting adaptive optics systems. Adaptive optics (AO) systems are used in various fields of application to enhance the performance of optical systems, such as imaging, laser, free space optical communication systems, etc. This book is intended for undergraduate and graduate students, professors, engineers, scientists and researchers working on the design of adaptive optics systems and their various emerging fields of application. Zhizheng Wu is an associate professor at Shanghai University, China. Azhar Iqbal is a research associate at the University of Toronto, Canada. Foue...

Focusing a laser beam by means of an off-centre parabolic mirror

International Nuclear Information System (INIS)

Rostaing, Michel.

In this study particular attention was paid to defining and optimizing a focusing system for concentrating a CO 2 laser beam (wave length lambda = 10.6 μm) on to a target containing a deuterium and tritium mixture. A digital study of the focusing of a spherical wave, in conjunction with the examination of the properties of reflecting surfaces led to the development of a focusing device using an off-centre parabolic mirror. Despite an aberration of 6 μm in the mirror, the lighting achieved experimentally in the plane of the circle of least scattering is 1.6 times greater than that achieved during the use of an NaCl spherical plane lense [fr

Topological mirror superconductivity.

Science.gov (United States)

Zhang, Fan; Kane, C L; Mele, E J

2013-08-02

We demonstrate the existence of topological superconductors (SCs) protected by mirror and time-reversal symmetries. D-dimensional (D=1, 2, 3) crystalline SCs are characterized by 2(D-1) independent integer topological invariants, which take the form of mirror Berry phases. These invariants determine the distribution of Majorana modes on a mirror symmetric boundary. The parity of total mirror Berry phase is the Z(2) index of a class DIII SC, implying that a DIII topological SC with a mirror line must also be a topological mirror SC but not vice versa and that a DIII SC with a mirror plane is always time-reversal trivial but can be mirror topological. We introduce representative models and suggest experimental signatures in feasible systems. Advances in quantum computing, the case for nodal SCs, the case for class D, and topological SCs protected by rotational symmetries are pointed out.

Fokker-Planck equation in mirror research

International Nuclear Information System (INIS)

Post, R.F.

1983-01-01

Open confinement systems based on the magnetic mirror principle depend on the maintenance of particle distributions that may deviate substantially from Maxwellian distributions. Mirror research has therefore from the beginning relied on theoretical predictions of non-equilibrium rate processes obtained from solutions to the Fokker-Planck equation. The F-P equation plays three roles: Design of experiments, creation of classical standards against which to compare experiment, and predictions concerning mirror based fusion power systems. Analytical and computational approaches to solving the F-P equation for mirror systems will be reviewed, together with results and examples that apply to specific mirror systems, such as the tandem mirror

Cryogenic systems for the Mirror Fusion Test Facility

International Nuclear Information System (INIS)

Slack, D.S.; Nelson, R.L.; Chronis, W.C.

1985-08-01

This paper includes an in-depth discussion of the design, fabrication, and operation of the Mirror Fusion Test Facility (MFTF) cryogenic system located at Lawrence Livermore National Laboratory (LLNL). Each subsystem discussed to present a basic composite of the entire facility. The following subsystems are included: 500kW nitrogen reliquefier, subcoolers, and distribution system; 15kW helium refrigerator/liquefier and distribution system; helium recovery and storage system; rough vacuum and high vacuum systems

Spatio-temporal dynamics of the mirror neuron system during social intentions.

Science.gov (United States)

Cacioppo, Stephanie; Bolmont, Mylene; Monteleone, George

2017-10-27

Previous research has shown that specific goals and intentions influence a person's allocation of social attention. From a neural viewpoint, a growing body of evidence suggests that the inferior fronto-parietal network, including the mirror neuron system, plays a role in the planning and the understanding of motor intentions. However, it is unclear whether and when the mirror neuron system plays a role in social intentions. Combining a behavioral task with electrical neuroimaging in 22 healthy male participants, the current study investigates whether the temporal brain dynamic of the mirror neuron system differs during two types of social intentions i.e., lust vs. romantic intentions. Our results showed that 62% of the stimuli evoking lustful intentions also evoked romantic intentions, and both intentions were sustained by similar activations of the inferior frontal gyrus and the inferior parietal lobule/angular gyrus for the first 432 ms after stimulus onset. Intentions to not love or not lust, on the other hand, were characterized by earlier differential activations of the inferior fronto-parietal network i.e., as early as 244 ms after stimulus onset. These results suggest that the mirror neuron system may not only code for the motor correlates of intentions, but also for the social meaning of intentions and its valence at both early/automatic and later/more elaborative stages of information processing.

Development of Slewing Mirror Telescope Optical System for the UFFO-pathfinder

DEFF Research Database (Denmark)

Jeong, S.; Nam, J.W.; Ahn, K.-B.

2013-01-01

The Slewing Mirror Telescope (SMT) is the UV/optical telescope of UFFO-pathfinder. The SMT optical system is a Ritchey-Chrétien (RC) telescope of 100 mm diameter pointed by means of a gimbal-mounted flat mirror in front of the telescope. The RC telescope has a 17 × 17arcmin2 in Field of View and ...

BOLDMirror: a global mirror system of DNA barcode data.

Science.gov (United States)

Liu, D; Liu, L; Guo, G; Wang, W; Sun, Q; Parani, M; Ma, J

2013-11-01

DNA barcoding is a novel concept for taxonomic identification using short, specific genetic markers and has been applied to study a large number of eukaryotes. The huge amount of data output generated by DNA barcoding requires well-organized information systems. Besides the Barcode of Life Data system (BOLD) established in Canada, the mirror system is also important for the international barcode of life project (iBOL). For this purpose, we developed the BOLDMirror, a global mirror system of DNA barcode data. It is open-sourced and can run on the LAMP (Linux + Apache + MySQL + PHP) environment. BOLDMirror has data synchronization, data representation and statistics modules, and also provides spaces to store user operation history. BOLDMirror can be accessed at http://www.boldmirror.net and several countries have used it to setup their site of DNA barcoding. © 2012 John Wiley & Sons Ltd.

Integrated fiber-mirror ion trap for strong ion-cavity coupling

International Nuclear Information System (INIS)

Brandstätter, B.; Schüppert, K.; Casabone, B.; Friebe, K.; Stute, A.; Northup, T. E.; McClung, A.; Schmidt, P. O.; Deutsch, C.; Reichel, J.; Blatt, R.

2013-01-01

We present and characterize fiber mirrors and a miniaturized ion-trap design developed to integrate a fiber-based Fabry-Perot cavity (FFPC) with a linear Paul trap for use in cavity-QED experiments with trapped ions. Our fiber-mirror fabrication process not only enables the construction of FFPCs with small mode volumes, but also allows us to minimize the influence of the dielectric fiber mirrors on the trapped-ion pseudopotential. We discuss the effect of clipping losses for long FFPCs and the effect of angular and lateral displacements on the coupling efficiencies between cavity and fiber. Optical profilometry allows us to determine the radii of curvature and ellipticities of the fiber mirrors. From finesse measurements, we infer a single-atom cooperativity of up to 12 for FFPCs longer than 200 μm in length; comparison to cavities constructed with reference substrate mirrors produced in the same coating run indicates that our FFPCs have similar scattering losses. We characterize the birefringence of our fiber mirrors, finding that careful fiber-mirror selection enables us to construct FFPCs with degenerate polarization modes. As FFPCs are novel devices, we describe procedures developed for handling, aligning, and cleaning them. We discuss experiments to anneal fiber mirrors and explore the influence of the atmosphere under which annealing occurs on coating losses, finding that annealing under vacuum increases the losses for our reference substrate mirrors. X-ray photoelectron spectroscopy measurements indicate that these losses may be attributable to oxygen depletion in the mirror coating. Special design considerations enable us to introduce a FFPC into a trapped ion setup. Our unique linear Paul trap design provides clearance for such a cavity and is miniaturized to shield trapped ions from the dielectric fiber mirrors. We numerically calculate the trap potential in the absence of fibers. In the experiment additional electrodes can be used to compensate

Modeling, performance analysis and economic feasibility of a mirror-augmented photovoltaic system

International Nuclear Information System (INIS)

Fortunato, B.; Torresi, M.; Deramo, A.

2014-01-01

Highlights: • Mathematical modeling for the energy yield in Mirror Augmented PV systems. • Simplified analytical expression for skyview factor applicable to MAPV. • Economic appraisal of MAPV systems: NPV, DPBP, IRR and LCC. - Abstract: In the last years, solar photovoltaic (PV) systems have had great impetus with research and demonstration projects, both in Italy and other European countries. The main problems with solar PV are the cost of solar electricity, which is still higher compared with other renewables (such as wind or biomass), due to the cost of semi-conductors, and the low conversion efficiency. However, PV panel prices are rapidly decreasing benefiting from favorable economies of scale. For instance, according to the Energy Information Administration (EIA) the US average levelized costs for plants entering service in the 2018 should be 144.3$/MW h for solar PV, whereas 111.0$/MW h for biomass and 86.6$/MW h for wind (Levelized Cost of New Generation Resources in the Annual Energy Outlook, 2013). In order to increase the electric yield of PV modules (which can be even doubled with respect to constant tilt configurations), without significantly increasing the system costs, it was decided to consider the addition of inclined mirrors at both sides of the PV modules, so as to deflect more solar rays towards them, as in Mirror-Augmented Photovoltaic (MAPV) systems. The system preserves its constructive simplicity with commercial flat PV modules even though dual axis tracker must be implemented, since MAPV systems harness mainly the direct radiation. The performance analysis of MAPV systems starts from the calculation of the global irradiation on the surface of the PV module which is a sum of the direct sunlight on it and the irradiation reflected by the mirrors. A mathematical model of a MAPV system is presented, which takes into account not only the increase of direct (or beam) radiation, due to the mirrors, but also the reduction of both the diffuse

Implications of the DAMA and CRESST experiments for mirror matter-type dark matter

International Nuclear Information System (INIS)

Foot, R.

2004-01-01

Mirror atoms are expected to be a significant component of the galactic dark matter halo if mirror matter is identified with the nonbaryonic dark matter in the Universe. Mirror matter can interact with ordinary matter via gravity and via the photon-mirror photon kinetic mixing interaction--causing mirror charged particles to couple to ordinary photons with an effective electric charge εe. This means that the nuclei of mirror atoms can elastically scatter off the nuclei of ordinary atoms, leading to nuclear recoils, which can be detected in existing dark matter experiments. We show that the dark matter experiments most sensitive to this type of dark matter candidate (via the nuclear recoil signature) are the DAMA/NaI and CRESST/Sapphire experiments. Furthermore, we show that the impressive annual modulation signal obtained by the DAMA/NaI experiment can be explained by mirror matter-type dark matter for vertical bar ε vertical bar ∼5x10 -9 and is supported by DAMA's absolute rate measurement as well as the CRESST/Sapphire data. This value of vertical bar ε vertical bar is consistent with the value obtained from various solar system anomalies including the Pioneer spacecraft anomaly, anomalous meteorite events and lack of small craters on the asteroid Eros. It is also consistent with standard big bang nucleosynthesis

Design of an ellipsoidal mirror for freewave characterization of materials at microwave frequencies

International Nuclear Information System (INIS)

Rojo, M; Muñoz, J; Molina-Cuberos, G J; Margineda, J; García-Collado, Á J

2016-01-01

Free-wave characterization of the electromagnetic properties of materials at microwave frequencies requires that scattering at the edges of the samples and/or holder be minimized. Here, an ellipsoidal mirror is designed and characterized in order to decrease the size of the beam, thereby avoiding the scattering problems, even when relatively small samples are used. In the experimental configuration, both the emitting antenna and sample are located at the mirror focuses. Since both the emitted and reflected (focused) beams are Gaussian in nature, we make use of Gaussian beam theory to carry out the design. The mirror parameters are optimized by numerical simulations (COMSOL Multiphysics ® ) and then experimentally tested. An experimental setup is presented for dielectric, magnetic and chiral measurement in the 4.5–18 GHz band. (paper)

OPTICAL DATA PROCESSING: Realization of associative memory with the aid of a nonlinear selective stimulated-Brillouin-scattering mirror

Science.gov (United States)

Matveyev, A. Z.; Pasmanik, G. A.

1993-05-01

An associative memory using only optical elements has been realized experimentally. The key element of the arrangement is a stimulated-Brillouin-scattering (SBS) selector consisting of a short SBS medium at the focus of a lens. The qualitative advantage of the selector over an SBS mirror is demonstrated experimentally. The response time of the arrangement is ~ 10-8 s and is determined by the duration of the SBS. Estimates show that the SBS selector is capable in practice of distinguishing a signal against background noise when the initial distortion level of the object beam is 10-3. Reliable operation of the SBS selector has been demonstrated for radiative and energy loads reaching 2 GW/cm2 and 2 J, respectively.

Mirror systems

International Nuclear Information System (INIS)

Howells, M.R.

1985-12-01

The physics of VUV and x-ray reflection is reviewed. The main functions of mirrors in synchrotron beamlines are stated briefly and include deflection, filtration, power absorption, formation of a real image of the source, focusing, and collimation. Methods of fabrication of optical surfaces are described. Types of imperfections are discussed, including, aberrations, surface figure inaccuracy, roughness, and degradation due to use. Calculation of the photon beam thermal load, including computer modelling, is considered. 50 refs., 7 figs

Laser-start-up system for magnetic mirror fusion

International Nuclear Information System (INIS)

Frank, A.M.; Thomas, S.R.; Denhoy, B.S.; Chargin, A.K.

1976-01-01

A CO 2 laser system has been developed at LLL to provide hot start-up plasmas for magnetic mirror fusion experiments. A frozen ammonia pellet is irradiated with a laser power density in excess of 10 13 W/cm 2 in a 50-ns pulse. This system uses commercially available laser systems. Optical components were fabricated both by direct machining and standard techniques. The technologies used in this system are directly applicable to reactor scale systems

Mechanical Design of the HER Synchrotron Light Monitor Primary Mirror

Energy Technology Data Exchange (ETDEWEB)

Daly, Edward F.; /SLAC; Fisher, Alan S.; Kurita, Nadine R.; Langton, J.; /SLAC

2011-09-14

This paper describes the mechanical design of the primary mirror that images the visible portion of the synchrotron radiation (SR) extracted from the High Energy Ring (HER) of the PEP-II B-Factory. During off-axis operation, the water-cooled GlidCop mirror is subjected to a heat flux in excess of 2000 W/cm2. When on-axis imaging occurs, the heat flux due to scattered SR, resistive wall losses and Higher-Order-Mode (HOM) heating is estimated at 1 W/cm2. The imaging surface is plated with Electroless Nickel to improve its optical characteristics. The design requirements for the primary mirror are listed and discussed. Calculated mechanical distortions and stresses experienced by the mirror during on-axis and off-axis operation will be presented.

Shape parameters measurement of ultralight mirrors

Czech Academy of Sciences Publication Activity Database

Pech, Miroslav; Mandát, Dušan; Hrabovský, Miroslav; Palatka, Miroslav; Schovánek, Petr

2010-01-01

Roč. 121, č. 20 (2010), s. 1881-1884 ISSN 0030-4026 R&D Projects: GA MŠk(CZ) 1M06002; GA AV ČR KAN301370701 Institutional research plan: CEZ:AV0Z10100522 Keywords : Hartmann test * roughness * scattering * BRDF * mirror shape Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.454, year: 2010

Remote Control System of the TJ-II Microwave Transmission Lines Mirrors

International Nuclear Information System (INIS)

Lopez Sanchez, A.; Fernandez, A.; Cappa, A.; Gama, J. de la; Olivares, J.; Garcia, R.; Chamorro, M.

2007-01-01

The ECRH system of the TJ-II stellarator has two gyrotrons, which deliver a maximum power of 300 kW each at a frequency of 53.2 GHz. Another 28 GHz gyrotron will be used to heat the plasma by electron Bernstein waves (EBWH). The microwave power is transmitted from the gyrotrons to the vacuum chamber by two quasi-optical transmission lines for ECRH and a corrugated waveguide for EBWH. All transmission lines have an internal movable mirror inside the vacuum chamber to focus the beam and to be able to change the launching angle. The control of the beam polarization is very important and the lines have two corrugated mirrors, which actuate as polarizers. In this report the control system of the position of these three internal mirrors and the polarizers of the EBWH transmission line is described. (Author) 20 refs

Cryogenic systems for the Mirror Fusion Test Facility

International Nuclear Information System (INIS)

Slack, D.S.; Chronis, W.C.; Nelson, R.L.

1986-01-01

This paper will include an in-depth discussion of the design, fabrication, and operation of the Mirror Fusion Test Facility (MFTF) cryogenic system located at Lawrence Livermore National Laboratory (LLNL). Each subsystem will be discussed to present a basic composite of the entire facility

Mirror neuron system: basic findings and clinical applications.

Science.gov (United States)

Iacoboni, Marco; Mazziotta, John C

2007-09-01

In primates, ventral premotor and rostral inferior parietal neurons fire during the execution of hand and mouth actions. Some cells (called mirror neurons) also fire when hand and mouth actions are just observed. Mirror neurons provide a simple neural mechanism for understanding the actions of others. In humans, posterior inferior frontal and rostral inferior parietal areas have mirror properties. These human areas are relevant to imitative learning and social behavior. Indeed, the socially isolating condition of autism is associated with a deficit in mirror neuron areas. Strategies inspired by mirror neuron research recently have been used in the treatment of autism and in motor rehabilitation after stroke.

What do mirror neurons mirror?

NARCIS (Netherlands)

Uithol, S.; Rooij, I.J.E.I. van; Bekkering, H.; Haselager, W.F.G.

2011-01-01

Single cell recordings in monkeys provide strong evidence for an important role of the motor system in action understanding. This evidence is backed up by data from studies of the (human) mirror neuron system using neuroimaging or TMS techniques, and behavioral experiments. Although the data

Design of control system for piezoelectric deformable mirror based on fuzzy self-adaptive PID control

Science.gov (United States)

Xiao, Nan; Gao, Wei; Song, Zongxi

2017-10-01

With the rapid development of adaptive optics technology, it is widely used in the fields of astronomical telescope imaging, laser beam shaping, optical communication and so on. As the key component of adaptive optics systems, the deformable mirror plays a role in wavefront correction. In order to achieve the high speed and high precision of deformable mirror system tracking control, it is necessary to find out the influence of each link on the system performance to model the system and design the controller. This paper presents a method about the piezoelectric deformable mirror driving control system.

A human mirror neuron system for language: Perspectives from signed languages of the deaf.

Science.gov (United States)

Knapp, Heather Patterson; Corina, David P

2010-01-01

Language is proposed to have developed atop the human analog of the macaque mirror neuron system for action perception and production [Arbib M.A. 2005. From monkey-like action recognition to human language: An evolutionary framework for neurolinguistics (with commentaries and author's response). Behavioral and Brain Sciences, 28, 105-167; Arbib M.A. (2008). From grasp to language: Embodied concepts and the challenge of abstraction. Journal de Physiologie Paris 102, 4-20]. Signed languages of the deaf are fully-expressive, natural human languages that are perceived visually and produced manually. We suggest that if a unitary mirror neuron system mediates the observation and production of both language and non-linguistic action, three prediction can be made: (1) damage to the human mirror neuron system should non-selectively disrupt both sign language and non-linguistic action processing; (2) within the domain of sign language, a given mirror neuron locus should mediate both perception and production; and (3) the action-based tuning curves of individual mirror neurons should support the highly circumscribed set of motions that form the "vocabulary of action" for signed languages. In this review we evaluate data from the sign language and mirror neuron literatures and find that these predictions are only partially upheld. 2009 Elsevier Inc. All rights reserved.

Cooperative scattering of scalar waves by optimized configurations of point scatterers

Science.gov (United States)

Schäfer, Frank; Eckert, Felix; Wellens, Thomas

2017-12-01

We investigate multiple scattering of scalar waves by an ensemble of N resonant point scatterers in three dimensions. For up to N = 21 scatterers, we numerically optimize the positions of the individual scatterers, to maximize the total scattering cross section for an incoming plane wave, on the one hand, and to minimize the decay rate associated to a long-lived scattering resonance, on the other. In both cases, the optimum is achieved by configurations where all scatterers are placed on a line parallel to the direction of the incoming plane wave. The associated maximal scattering cross section increases quadratically with the number of scatterers for large N, whereas the minimal decay rate—which is realized by configurations that are not the same as those that maximize the scattering cross section—decreases exponentially as a function of N. Finally, we also analyze the stability of our optimized configurations with respect to small random displacements of the scatterers. These results demonstrate that optimized configurations of scatterers bear a considerable potential for applications such as quantum memories or mirrors consisting of only a few atoms.

Thermal effects on beryllium mirrors

International Nuclear Information System (INIS)

Weinswig, S.

1989-01-01

Beryllium is probably the most frequently used material for spaceborne system scan mirrors. Beryllium's properties include lightweightedness, high Young's modulus, high stiffness value, high resonance value. As an optical surface, beryllium is usually nickel plated in order to produce a higher quality surface. This process leads to the beryllium mirror acting like a bimetallic device. The mirror's deformation due to the bimetallic property can possibly degrade the performance of the associated optical system. As large space borne systems are designed and as temperature considerations become more crucial in the instruments, the concern about temporal deformation of the scan mirrors becomes a prime consideration. Therefore, two sets of tests have been conducted in order to ascertain the thermal effects on nickel plated beryllium mirrors. These tests are categorized. The purpose of this paper is to present the values of the bimetallic effect on typical nickel plated beryllium mirrors

Multiple-mirror plasma confinement

International Nuclear Information System (INIS)

Lichtenberg, A.J.; Lieberman, M.A.; Logan, B.G.

1975-01-01

A large enhancement of the confinement time can be achieved in a straight system of multiple mirrors over an equal length uniform magnetic field. The scaling is diffusive rather than that of flow, thereby scaling the square of the system length rather than linear with system length. Probably the most economic mode of operation for a reactor occurs when lambda/M is approximately l/sub c/, where lambda is the mean free path, M the mirror ratio, and l/sub c/ the length between mirrors; but where the scale length of the mirror field l/sub m/ is much less than lambda. The axial confinement time has been calculated theoretically and numerically for all important parameter regimes, and confirmed experimentally. A typical reactor calculation gives Q/sub E/ = 2 for a 400 meter system with 3000 MW(e) output. The main concern of a multiple-mirror system is stability. Linked quadrupoles can achieve average minimum-B stabilization of flute modes, and experiments have demonstrated this stabilization. Localized instabilities at finite β and enhanced diffusion resulting from the distorted flux surfaces and possibly from turbulent higher order modes still remain to be investigated

Current trends in laser fusion driver and beam combination laser system using stimulated Brillouin scattering phase conjugate mirrors for a fusion driver

International Nuclear Information System (INIS)

Kong, Hong Jin

2008-01-01

Laser fusion energy (LFE) is well known as one of the promising sources if clean energy for mankind. Laser fusion researches have been actively progressed, since Japan and the Soviet Union as well as USA developed ultrahigh power lasers at the beginning of 1970s. At present in USA, NIF (National Ignition Facility), which is the largest laser fusion facility in the world, is under construction and will be completed in 2008. Japan as a leader of the laser fusion research has developed a high energy and high power laser system, Gekko XII, and is under contemplation of FIREX projects for the fast ignition. China also has SG I, II lasers for performing the fusion research, and SG III is under construction as a next step. France is also constructing LMJ (Laser countries, many other developed countries in Europe, such as Russia, Germany, UK, and so on, have their own high energy laser systems for the fusion research. In Korea, the high power laser development started with SinMyung laser in KAIST in 1994, and KLF (KAERI Laser Facility) of KAERI was recently completed in 2007. For the practical use of laser fusion energy, the laser driver should be operated with a high repetition rate around 10Hz. Yet, current high energy laser systems, Such as NIF, Gekko XII, and etc., can be operated with only several shots per day. Some researchers have developed their own techniques to reduce the thermal loads of the laser material, by using laser diodes as pump sources and ceramic laser materials with high thermal energy scaling up for the real fusion driver. For this reason, H. J. Kong et al. proposed the beam combination laser system using stimulated Brillouin scattering phase conjugate mirrors (SBS PCMs) for a fusion driver. Proposed beam combination has many advantages for energy scaling up; it is composed by simple optical systems with small amount of components, there is no interaction between neighbored sub beams, the SBS PCMs can be used for a high energy beam reflection with

U. S. Mirror Program

International Nuclear Information System (INIS)

Fowler, T.K.

1978-01-01

The mirror approach is now the principal alternate to the tokamak in the U.S. magnetic fusion energy program. The program is now focused on two new concepts that can obtain high values of Q, defined as the ratio of fusion power output to the neutral beam power injected to sustain the reaction. These are the tandem mirror and field reversed mirror concepts. Theoretically both concepts should be able to attain Q = 5 or more, as compared with Q approximately 1 in previous mirror designs. Success with either or both of these approaches would point the way toward fusion power plants with many attractive features. The linear geometry of mirror systems offers a distinct alternative to the toroidal tokamak. As a direct consequence of this difference in geometry, it is generally possible to build mirror systems in smaller units of modular construction that can probably be made to operate in steady-state. During the next 5 years the main mirror facilities in the U.S. will be the 2XIIB (renamed Beta II); a tandem mirror experiment caled TMX; and the Mirror Fusion Test Facility (MFTF) scheduled to be completed in 1981 at a cost of $94 million. As a background for discussing this program and mirror reactor concepts in later lectures, the current status of mirror physics will be reviewed by comparing theory and experimental data in four critical areas. These are adiabatic confinement of individual ions, electron heat losses out of the ends of the machine, the achievement of beta values of order unity; and stabilization of ''loss cone'' modes

Specular reflectance of soiled glass mirrors - Study on the impact of incidence angles

Science.gov (United States)

Heimsath, Anna; Lindner, Philip; Klimm, Elisabeth; Schmid, Tobias; Moreno, Karolina Ordonez; Elon, Yehonatan; Am-Shallem, Morag; Nitz, Peter

2016-05-01

The accumulation of dust and soil on the surface of solar reflectors is an important factor reducing the power output of solar power plants. Therefore the effect of accumulated dust on the specular reflectance of solar mirrors should be understood well in order to improve the site-dependent performance prediction. Furthermore, an optimization of the CSP System maintenance, in particular the cleaning cycles, can be achieved. Our measurements show a noticeable decrease of specular reflectance when the angle of incidence is increased. This effect may be explained by shading and blocking mechanisms caused by dirt particles. The main physical causes of radiation loss being absorption and scattering, the near-angle scattering leads to a further decrease of specular reflectance for smaller angles of acceptance. Within this study mirror samples were both outdoor exposed and indoor artificially soiled. For indoor soiling, the mirror samples were artificially soiled in an in-house developed dusting device using both artificial-standardized dust and real dust collected from an arid outdoor test field at the Negev desert. A model function is proposed that approximates the observed reduction of specular reflectance with the incidence angle with a sufficient accuracy and by simple means for this soil type. Hence a first step towards a new approach to improve site dependent performance prediction of solar power plants is taken.

Tandem mirror and field-reversed mirror experiments

Energy Technology Data Exchange (ETDEWEB)

Coensgen, F.H.; Simonen, T.C.; Turner, W.C.

1979-08-21

This paper is largely devoted to tandem mirror and field-reversed mirror experiments at the Lawrence Livermore Laboratory (LLL), and briefly summarizes results of experiments in which field-reversal has been achieved. In the tandem experiment, high-energy, high-density plasmas (nearly identical to 2XIIB plasmas) are located at each end of a solenoid where plasma ions are electrostatically confined by the high positive poentials arising in the end plug plasma. End plug ions are magnetically confined, and electrons are electrostatically confined by the overall positive potential of the system. The field-reversed mirror reactor consists of several small field-reversed mirror plasmas linked together for economic reasons. In the LLL Beta II experiment, generation of a field-reversed plasma ring will be investigated using a high-energy plasma gun with a transverse radial magnetic field. This plasma will be further heated and sustained by injection of intense, high-energy neutral beams.

MHD-Stabilization of Axisymmetric Mirror Systems Using Pulsed ECRH

International Nuclear Information System (INIS)

Post, R.F.

2010-01-01

This paper, part of a continuing study of means for the stabilization of MHD interchange modes in axisymmertric mirror-based plasma confinement systems, is aimed at a preliminary look at a technique that would employ a train of plasma pressure pulses produced by ECRH to accomplish the stabilization. The purpose of using sequentially pulsed ECRH rather than continuous-wave ECRH is to facilitate the localization of the heated-electron plasma pulses in regions of the magnetic field with a strong positive field-line curvature, e. g. in the 'expander' region of the mirror magnetic field, outside the outermost mirror, or in other regions of the field with positive field-line curvature. The technique proposed, of the class known as 'dynamic stabilization,' relies on the time-averaged effect of plasma pressure pulses generated in regions of positive field-line curvature to overcome the destabilizing effect of plasma pressure in regions of negative field-line curvature within the confinement region. As will also be discussed in the paper, the plasma pulses, when produced in regions of the confining having a negative gradient, create transient electric potentials of ambipolar origin, an effect that was studied in 1964 in The PLEIDE experiment in France. These electric fields preserve the localization of the hot-electron plasma pulses for a time determined by ion inertia. It is suggested that it may be possible to use this result of pulsed ECRH not only to help to stabilize the plasma but also to help plug mirror losses in a manner similar to that employed in the Tandem Mirror.

A novel mirror diversity receiver for indoor MIMO visible light communication systems

KAUST Repository

Park, Kihong

2016-12-24

In this paper, we propose and study a non-imaging receiver design reducing the correlation of channel matrix for indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. Contrary to previous works, our proposed mirror diversity receiver (MDR) not only blocks the reception of light on one specific direction but also improves the channel gain on the other direction by receiving the light reflected by a mirror deployed between the photodetectors. We analyze the channel capacity and optimal height of mirror in terms of maximum channel capacity for a 2 × 2 MIMO-VLC system in a 2-dimensional geometric model. We prove that this constructive and destructive effects in channel matrix resulting from our proposed MDR are more beneficial to obtain well-conditioned channel matrix which is suitable for implementing spatial-multiplexing MIMO-VLC systems in order to support high data rate.

Proposal of a wide-band mirror polarizer of slow neutrons at a pulsed neutron source

International Nuclear Information System (INIS)

Nikitenko, Yu.V.; Ostanevich, Yu.M.

1992-01-01

The new type wide-band mirror-based neutron polarizer to be operated at a pulsed neutron source is suggested. The idea is to use a movable polarizing mirror system, which, be the incoming beam monochromatized by the time-of-flight, would allow one to tune glancing angles in time so, that the total reflection condition is always fulfilled only for one of the two neutron spin eigenstates. Estimates show, that with the pulsed reactor IBR-2 such polarizer allows one to build a small-angle neutron scattering instrument capable to effectively use the wave-length band from 2 to 15 A. 9 refs.; 1 fig

Rough Mirror as a Quantum State Selector: Analysis and Design

International Nuclear Information System (INIS)

Nesvizhevsky, V. V.; Lamy, F.; Meyerovich, A. E.; Escobar, M.

2014-01-01

We report analysis of rough mirrors used as the gravitational state selectors in neutron beam and similar experiments. The key to mirror properties is its roughness correlation function (CF) which is extracted from the precision optical scanning measurements of the surface profile. To identify CF in the presence of fluctuation-driven fat tails, we perform numerical experiments with computer-generated random surfaces with the known CF. These numerical experiments provide a reliable identification procedure which we apply to the actual rough mirror. The extracted CF allows us to make predictions for ongoing GRANIT experiments. We also propose a radically new design for rough mirrors based on Monte Carlo simulations for the 1D Ising model. The implementation of this design provides a controlled environment with predictable scattering properties

Interpersonal motor resonance in autism spectrum disorder: evidence against a global "mirror system" deficit.

Science.gov (United States)

Enticott, Peter G; Kennedy, Hayley A; Rinehart, Nicole J; Bradshaw, John L; Tonge, Bruce J; Daskalakis, Zafiris J; Fitzgerald, Paul B

2013-01-01

The mirror neuron hypothesis of autism is highly controversial, in part because there are conflicting reports as to whether putative indices of mirror system activity are actually deficient in autism spectrum disorder (ASD). Recent evidence suggests that a typical putative mirror system response may be seen in people with an ASD when there is a degree of social relevance to the visual stimuli used to elicit that response. Individuals with ASD (n = 32) and matched neurotypical controls (n = 32) completed a transcranial magnetic stimulation (TMS) experiment in which the left primary motor cortex (M1) was stimulated during the observation of static hands, individual (i.e., one person) hand actions, and interactive (i.e., two person) hand actions. Motor-evoked potentials (MEP) were recorded from the contralateral first dorsal interosseous, and used to generate an index of interpersonal motor resonance (IMR; a putative measure of mirror system activity) during action observation. There was no difference between ASD and NT groups in the level of IMR during the observation of these actions. These findings provide evidence against a global mirror system deficit in ASD, and this evidence appears to extend beyond stimuli that have social relevance. Attentional and visual processing influences may be important for understanding the apparent role of IMR in the pathophysiology of ASD.

Does dysfunction of the mirror neuron system contribute to symptoms in amyotrophic lateral sclerosis?

Science.gov (United States)

Eisen, Andrew; Lemon, Roger; Kiernan, Matthew C; Hornberger, Michael; Turner, Martin R

2015-07-01

There is growing evidence that mirror neurons, initially discovered over two decades ago in the monkey, are present in the human brain. In the monkey, mirror neurons characteristically fire not only when it is performing an action, such as grasping an object, but also when observing a similar action performed by another agent (human or monkey). In this review we discuss the origin, cortical distribution and possible functions of mirror neurons as a background to exploring their potential relevance in amyotrophic lateral sclerosis (ALS). We have recently proposed that ALS (and the related condition of frontotemporal dementia) may be viewed as a failure of interlinked functional complexes having their origins in key evolutionary adaptations. This can include loss of the direct projections from the corticospinal tract, and this is at least part of the explanation for impaired motor control in ALS. Since, in the monkey, corticospinal neurons also show mirror properties, ALS in humans might also affect the mirror neuron system. We speculate that a defective mirror neuron system might contribute to other ALS deficits affecting motor imagery, gesture, language and empathy. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Where do mirror neurons come from?

Science.gov (United States)

Heyes, Cecilia

2010-03-01

Debates about the evolution of the 'mirror neuron system' imply that it is an adaptation for action understanding. Alternatively, mirror neurons may be a byproduct of associative learning. Here I argue that the adaptation and associative hypotheses both offer plausible accounts of the origin of mirror neurons, but the associative hypothesis has three advantages. First, it provides a straightforward, testable explanation for the differences between monkeys and humans that have led some researchers to question the existence of a mirror neuron system. Second, it is consistent with emerging evidence that mirror neurons contribute to a range of social cognitive functions, but do not play a dominant, specialised role in action understanding. Finally, the associative hypothesis is supported by recent data showing that, even in adulthood, the mirror neuron system can be transformed by sensorimotor learning. The associative account implies that mirror neurons come from sensorimotor experience, and that much of this experience is obtained through interaction with others. Therefore, if the associative account is correct, the mirror neuron system is a product, as well as a process, of social interaction. (c) 2009 Elsevier Ltd. All rights reserved.

The mirror neuron system and the strange case of Broca's area.

Science.gov (United States)

Cerri, Gabriella; Cabinio, Monia; Blasi, Valeria; Borroni, Paola; Iadanza, Antonella; Fava, Enrica; Fornia, Luca; Ferpozzi, Valentina; Riva, Marco; Casarotti, Alessandra; Martinelli Boneschi, Filippo; Falini, Andrea; Bello, Lorenzo

2015-03-01

Mirror neurons, originally described in the monkey premotor area F5, are embedded in a frontoparietal network for action execution and observation. A similar Mirror Neuron System (MNS) exists in humans, including precentral gyrus, inferior parietal lobule, and superior temporal sulcus. Controversial is the inclusion of Broca's area, as homologous to F5, a relevant issue in light of the mirror hypothesis of language evolution, which postulates a key role of Broca's area in action/speech perception/production. We assess "mirror" properties of this area by combining neuroimaging and intraoperative neurophysiological techniques. Our results show that Broca's area is minimally involved in action observation and has no motor output on hand or phonoarticulatory muscles, challenging its inclusion in the MNS. The presence of these functions in premotor BA6 makes this area the likely homologue of F5 suggesting that the MNS may be involved in the representation of articulatory rather than semantic components of speech. © 2014 Wiley Periodicals, Inc.

Kodak AMSD Mirror Development Program

Science.gov (United States)

Matthews, Gary; Dahl, Roger; Barrett, David; Bottom, John; Russell, Kevin (Technical Monitor)

2002-01-01

The Advanced Mirror System Demonstration Program is developing minor technology for the next generation optical systems. Many of these systems will require extremely lightweight and stable optics due to the overall size of the primary mirror. These segmented, deployable systems require new technology that AMSD is developing. The on-going AMSD program is a critical enabler for Next Generation Space Telescope (NGST) which will start in 2002. The status of Kodak's AMSD mirror and future plans will be discussed with respect to the NGST program.

Mirror confinement systems: Final technical report

International Nuclear Information System (INIS)

1988-08-01

This report contains: (1) A discussion of azimuthal asymmetrics and fluctuations in RFC-XX-M. Both lead to enhanced radial transport in RFC-XX-M, and presumably most other tandem mirror machines as well; A report on four operating modes of RFC-XX-M which were developed and studied as part of the collaboration. These operating modes were the simple tandem mode, the negative (floating) potential mode, the hot electron mode, and the ECH (electron cyclotron heating) mode; A pulsed rf heated discharge cleaning system which was developed for RFC-XX-M. This method of cleaning proved much more effective than normal glow discharge cleaning, and variations of it are currently in use on the GAMMA-10 tandem mirror and the JIPP TII-U tokamak at the Institute for Plasma Physics at Nagoya; Short descriptions of the diagnostics development and improvement done in conjunction with the work on RFC-XX-M; and a compilation of the work performed at the University of Tsukuba on GAMMA-10. Most of the effort on GAMMA-10 involved diagnostics development and improvement. 16 refs., 42 figs., 1 tab

Sensing small changes in a wave chaotic scattering system

International Nuclear Information System (INIS)

Taddese, Biniyam Tesfaye; Antonsen, Thomas M.; Ott, Edward; Anlage, Steven M.

2010-01-01

Classical analogs of the quantum mechanical concepts of the Loschmidt Echo and quantum fidelity are developed with the goal of detecting small perturbations in a closed wave chaotic region. Sensing techniques that employ a one-recording-channel time-reversal-mirror, which in turn relies on time reversal invariance and spatial reciprocity of the classical wave equation, are introduced. In analogy with quantum fidelity, we employ scattering fidelity techniques which work by comparing response signals of the scattering region, by means of cross correlation and mutual information of signals. The performance of the sensing techniques is compared for various perturbations induced experimentally in an acoustic resonant cavity. The acoustic signals are parametrically processed to mitigate the effect of dissipation and to vary the spatial diversity of the sensing schemes. In addition to static boundary condition perturbations at specified locations, perturbations to the medium of wave propagation are shown to be detectable, opening up various real world sensing applications in which a false negative cannot be tolerated.

Conceptual Design Studies of the KSTAR Bay-Nm Cassette and Thomson Scattering Optics

International Nuclear Information System (INIS)

Feder, R.; Ellis, R.; Johnson, D.; Park, H.; Lee, H.G.

2005-01-01

A Multi-Channel Thomson Scattering System viewing the edge and core of the KSTAR plasma will be installed at the mid-plane port Bay-N. An engineering design study was undertaken at PPPL in collaboration with the Korea Basic Science Institute (KBSI) to determine the optimal optics and cassette design. Design criteria included environmental, mechanical and optical factors. All of the optical design options have common design features; the Thomson Scattering laser, an in-vacuum shutter, a quartz heat shield and primary vacuum window, a set of optical elements and a fiber optic bundle. Neutron radiation damage was a major factor in the choice of competing lens-based and mirror-based optical designs. Both the mirror based design and the lens design are constrained by physical limits of the Bay-N cassette and interference with the Bay-N micro-wave launcher. The cassette will contain the optics and a rail system for maintenance of the optics

Tandem mirror magnet system for the mirror fusion test facility

International Nuclear Information System (INIS)

Bulmer, R.H.; Van Sant, J.H.

1980-01-01

The Tandem Mirror Fusion Test Facility (MFTF-B) will be a large magnetic fusion experimental facility containing 22 supercounducting magnets including solenoids and C-coils. State-of-the-art technology will be used extensively to complete this facility before 1985. Niobium titanium superconductor and stainless steel structural cases will be the principle materials of construction. Cooling will be pool boiling and thermosiphon flow of 4.5 K liquid helium. Combined weight of the magnets will be over 1500 tonnes and the stored energy will be over 1600 MJ. Magnetic field strength in some coils will be more than 8 T. Detail design of the magnet system will begin early 1981. Basic requirements and conceptual design are disclosed in this paper

Exact solutions to nonlinear symmetron theory: One- and two-mirror systems

Science.gov (United States)

Brax, Philippe; Pitschmann, Mario

2018-03-01

We derive the exact analytical solutions to the symmetron field theory equations in the presence of a one- or two-mirror system. The one-dimensional equations of motion are integrated exactly for both systems and their solutions can be expressed in terms of Jacobi elliptic functions. Surprisingly, in the case of two parallel mirrors, the equations of motion generically provide not a unique solution but a discrete set of solutions with increasing number of nodes and energies. The solutions obtained herein can be applied to q BOUNCE experiments, neutron interferometry and for the calculation of the symmetron-field-induced "Casimir force" in the CANNEX experiment.

Neutron scattering. Experiment manuals

International Nuclear Information System (INIS)

Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

2014-01-01

The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot-single-crystal diffractometer HEiDi, the three-axis spectrometer PANDA, the backscattering spectrometer SPHERES, the DNS neutron-polarization analysis, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering at KWS-1 and KWS-2, a very-small-angle neutron scattering diffractometer with focusing mirror, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

Neutral beam control systems for the Tandem Mirror Experiment

International Nuclear Information System (INIS)

Ross, R.I.

1979-01-01

The Tandem Mirror Experiment (TMX) is presently developing the technology and approaches which will be used in larger fusion systems. This paper describes some of the designs which were used in creating the control system for the TMX neutral beams. To create a system of controls that would work near these large, rapid switching current sources required a mixture of different technologies: fiberoptic data transmission, printed circuit and wirewrap techniques, etc

Optimization of an Angle-Aided Mirror Diversity Receiver for Indoor MIMO-VLC Systems

KAUST Repository

Park, Kihong

2017-02-07

In this paper, we investigate the channel correlation problem which affects the performance of indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. More specifically, in order to reduce the high correlation of channel matrix in MIMO-VLC intensity channel, we propose a non-imaging receiver called angle-aided mirror diversity receiver (AMDR) which utilizes not only a mirror placement but also a variation of orientation angle for the photodetector (PD) plane. Deploying a mirror helps reducing the correlation by blocking the reception of the light in one specific direction and by receiving additional light reflected in the mirror in another direction, while orienting the angle of PD plane into specific direction enables the directional reception of light. Applying a zero-forcing decorrelator at the receiver, we analyze the bit error rate (BER) performance for a 2×2 multiplexing MIMO-VLC system using a 2-dimensional geometric model. In particular, we formulate a min-max BER problem and find the optimal height of mirror and elevation angle of PD plane. Some selected numerical results validate our proposed optimal solution to our min-max BER problem and show that the BER performance of our proposed AMDR outperforms that of the previous non-imaging receivers.

Optimization of an Angle-Aided Mirror Diversity Receiver for Indoor MIMO-VLC Systems

KAUST Repository

Park, Kihong; Alouini, Mohamed-Slim

2017-01-01

In this paper, we investigate the channel correlation problem which affects the performance of indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. More specifically, in order to reduce the high correlation of channel matrix in MIMO-VLC intensity channel, we propose a non-imaging receiver called angle-aided mirror diversity receiver (AMDR) which utilizes not only a mirror placement but also a variation of orientation angle for the photodetector (PD) plane. Deploying a mirror helps reducing the correlation by blocking the reception of the light in one specific direction and by receiving additional light reflected in the mirror in another direction, while orienting the angle of PD plane into specific direction enables the directional reception of light. Applying a zero-forcing decorrelator at the receiver, we analyze the bit error rate (BER) performance for a 2×2 multiplexing MIMO-VLC system using a 2-dimensional geometric model. In particular, we formulate a min-max BER problem and find the optimal height of mirror and elevation angle of PD plane. Some selected numerical results validate our proposed optimal solution to our min-max BER problem and show that the BER performance of our proposed AMDR outperforms that of the previous non-imaging receivers.

The simplest possible design for a KB microfocus mirror system?

Energy Technology Data Exchange (ETDEWEB)

Collins, S. P., E-mail: steve.collins@diamond.ac.uk; Scott, S. M.; Hawkins, D. M.; Fabrizi, F.; Moser, B.; Nisbet, G.; Sutter, J. P. [Diamond Light Source, Harwell Science & Innovation Campus, Didcot, OX11 0DE (United Kingdom); Harwin, R. C. [Diamond Light Source, Harwell Science & Innovation Campus, Didcot, OX11 0DE (United Kingdom); Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom); Harwin, W. S. [School of Systems Engineering, University of Reading, Whiteknights, Reading, Berkshire, RG6 6AH (United Kingdom)

2016-07-27

We report a design for a Kirkpatrick-Baez (KB) microfocussing mirror system. The main components are described, with emphasis on a ‘tripod’ manipulator, where we outline the required coordinate transformation calculations. The merit of this device lies in its simplicity of design, minimal degrees of freedom, and speed and ease of setup on a beamline. Test results and an example of the mirrors in use on Diamond Beamline I16, showing a high-resolution polar domain map of KTiOPO{sub 4} with a spot size of 1.25 µm × 1.5 µm, are presented.

Recent advances in Thomson scattering: high repetition rate Thomson scattering diagnostics on large plasma devices

International Nuclear Information System (INIS)

Roehr, H.; Steuer, K.H.; Hirsch, K.; Salzmann, H.

1982-09-01

In contrast to conventional ruby laser scattering devices allowing only singly pulse measurements, time evolution of Te and ne can be obtained with multipulse lasers. Within a short time interval ( proportional 1 ms) rapid variations can be investigated by employing a periodically Q-switched ruby laser. Several scattering systems under construction in different laboratories to register the time evolution of Tsub(e) and nsub(e) during the whole plasma discharge will be reported. The set-up operating successfully on the Garching tokamak ASDEX will be described in detail. This scattering system uses a Nd:YAG laser (1 J/pulse, up to 100 pps, pulse duration 30 ns, burst of max. 400 pulses) and silicon avalanche diodes as detectors. Time resolved nsub(e) and Tsub(e) measurements on different types of ASDEX discharges are shown, e.g. the electron density and electron heating during neutral beam injection in a divertor discharge. As an example of relatively fast changes of nsub(e) and Tsub(e), results on pellet injection are presented. Interferometric and ECE measurements are in good agreement with the Thomson results. Stationary ''long pulse discharges'' in ASDEX (10 s) at low densitites (10 12 cm -3 ) were diagnosed with reduced time resolution by averaging over several laser pulses. Measurements of the time evolution of electron temperature and -density profiles were done in a first step with a scanning mirror system. These results enables optimazing out 15 spatial-point Thomson scattering system on ASDEX. (orig./AH)

Forward scattering of polarized light from a turbid slab: theory and Monte Carlo simulations.

Science.gov (United States)

Otsuki, Soichi

2016-12-20

It is proved that if reciprocity and mirror symmetry hold for single scattering by a particle, they also hold for multiple scattering in turbid slab media. Monte Carlo simulations generate a reduced effective Mueller matrix for forward scattering, which satisfies reciprocity and mirror symmetry, but satisfies only reciprocity if the medium contains chiral components. The scattering matrix was factorized by using the Lu-Chipman polar decomposition, which affords the polarization parameters as a function of the radial distance from the center. The depolarization coefficients decrease with increasing distance, whereas the scattering-induced linear diattenuation and retardance become larger in the middle-distance range. The optical rotation for a chiral medium increases with increasing distance.

Grating exchange system of independent mirror supported by floating rotary stage

Science.gov (United States)

Zhang, Jianhuan; Tao, Jin; Liu, Yan; Nan, Yan

2015-10-01

The performance of The Grating Exchange System can satisfy the Thirty Meter Telescope - TMT for astronomical observation WFOS index requirements and satisfy the requirement of accuracy in the grating exchange. It is used to install in the MOBIE and a key device of MOBIE. The Wide Field Optical Spectrograph (WFOS) is one of the three first-light observing capabilities selected by the TMT Science Advisory Committee. The Multi-Object Broadband Imaging Echellette (MOBIE) instrument design concept has been developed to address the WFOS requirements as described in the TMT Science-Based Requirements Document (SRD). The Grating Exchange System uses a new type of separate movement way of three grating devices and a mirror device. Three grating devices with a mirror are able to achieve independence movement. This kind of grating exchange system can effectively solve the problem that the volume of the grating change system is too large and that the installed space of MOBIE instruments is too limit. This system adopts the good stability, high precision of rotary stage - a kind of using air bearing (Air bearing is famous for its ultra-high precision, and can meet the optical accuracy requirement) and rotation positioning feedback gauge turntable to support grating device. And with a kind of device which can carry greater weight bracket fixed on the MOBIE instrument, with two sets of servo motor control rotary stage and the mirror device respectively. And we use the control program to realize the need of exercising of the grating device and the mirror device. Using the stress strain analysis software--SolidWorks for stress and strain analysis of this structure. And then checking the structure of the rationality and feasibility. And prove that this system can realize the positioning precision under different working conditions can meet the requirements of imaging optical grating diffraction efficiency and error by the calculation and optical performance analysis.

Complete mitochondrial genome of Yangtze River wild common carp (Cyprinus carpio haematopterus) and Russian scattered scale mirror carp (Cyprinus carpio carpio).

Science.gov (United States)

Hu, Guang Fu; Liu, Xiang Jiang; Zou, Gui Wei; Li, Zhong; Liang, Hong-Wei; Hu, Shao-Na

2016-01-01

We sequenced the complete mitogenomes of (Cyprinus carpio haematopterus) and Russian scattered scale mirror carp (Cyprinus carpio carpio). Comparison of these two mitogenomes revealed that the mitogenomes of these two common carp strains were remarkably similar in genome length, gene order and content, and AT content. There were only 55 bp variations in 16,581 nucleotides. About 1 bp variation was located in rRNAs, 2 bp in tRNAs, 9 bp in the control region and 43 bp in protein-coding genes. Furthermore, forty-three variable nucleotides in the protein-coding genes of the two strains led to four variable amino acids, which were located in the ND2, ATPase 6, ND5 and ND6 genes, respectively.

Mirror fusion--fission hybrids

International Nuclear Information System (INIS)

Lee, J.D.

1978-01-01

The fusion-fission concept and the mirror fusion-fission hybrid program are outlined. Magnetic mirror fusion drivers and blankets for hybrid reactors are discussed. Results of system analyses are presented and a reference design is described

Concept and design of an alignment monitoring system for the CBM RICH mirrors

Energy Technology Data Exchange (ETDEWEB)

Bendarouach, Jordan [Justus Liebig University (Germany); Collaboration: CBM-Collaboration

2016-07-01

The Compressed Baryonic Matter (CBM) experiment at the future FAIR (Facility for Antiproton and Ion Research) complex will investigate the phase diagram of strongly interacting matter at high baryon density and moderate temperatures in A+A collisions from 2-11 AGeV (SIS100) beam energy. One of the key detector components required for this CBM physics program is the RICH (Ring Imaging CHerenkov) detector, developed for efficient and clean electron identification and pion suppression. The detector consists of about 80 spherical glass mirror tiles, distributed over two sphere parts. An important aspect to guarantee a stable operation of the RICH detector is the alignment of the mirrors. A method originally developed and inspired by the HERA-B experiment uses recorded data to assess mirror alignment of the RICH mirror system. Measurements of Cherenkov distances and angles on the PMT plane may reveal potential misalignments of the considered tile. If mirror misalignment is revealed, it can be subsequently included and rectified by correction routines, which should mostly increase ring reconstruction as well as ring-track matching efficiencies. Results of this alignment method based on simulated events, reproducing potential mirror misalignments, its limits and first correction routines are presented.

Mirror boxes and mirror mounts for photophysics beamline

International Nuclear Information System (INIS)

Raja Rao, P.M.; Raja Sekhar, B.N.; Das, N.C.; Khan, H.A.; Bhattacharya, S.S.; Roy, A.P.

1996-01-01

Photophysics beamline makes use of one metre Seya-Namioka monochromator and two toroidal mirrors in its fore optics. The first toroidal mirror (pre mirror) focuses light originating from the tangent point of the storage ring onto the entrance slit of the monochromator and second toroidal mirror (post mirror) collects light from the exit slit of the monochromator and focuses light onto the sample placed at a distance of about one metre away from the 2nd mirror. To steer light through monochromator and to focus it on the sample of 1mm x 1mm size require precision rotational and translational motion of the mirrors and this has been achieved with the help of precision mirror mounts. Since Indus-1 operates at pressures less than 10 -9 m.bar, the mirror mounts should be manipulated under similar ultra high vacuum conditions. Considering these requirements, two mirror boxes and two mirror mounts have been designed and fabricated. The coarse movements to the mirrors are imparted from outside the mirror chamber with the help of x-y tables and precision movements to the mirrors are achieved with the help of mirror mounts. The UHV compatibility and performance of the mirror mounts connected to mirror boxes under ultra high vacuum condition is evaluated. The details of the design, fabrication and performance evaluation are discussed in this report. 5 refs., 9 figs., 1 tab

Empathy and the somatotopic auditory mirror system in humans

NARCIS (Netherlands)

Gazzola, Valeria; Aziz-Zadeh, Lisa; Keysers, Christian

2006-01-01

How do we understand the actions of other individuals if we can only hear them? Auditory mirror neurons respond both while monkeys perform hand or mouth actions and while they listen to sounds of similar actions [1, 2]. This system might be critical for auditory action understanding and language

On Empathy: The Mirror Neuron System and Art Education

Science.gov (United States)

Jeffers, Carol S.

2009-01-01

This paper re/considers empathy and its implications for learning in the art classroom, particularly in light of relevant neuroscientific investigations of the mirror neuron system recently discovered in the human brain. These investigations reinterpret the meaning of perception, resonance, and connection, and point to the fundamental importance…

Effective theory of flavor for Minimal Mirror Twin Higgs

Science.gov (United States)

Barbieri, Riccardo; Hall, Lawrence J.; Harigaya, Keisuke

2017-10-01

We consider two copies of the Standard Model, interchanged by an exact parity symmetry, P. The observed fermion mass hierarchy is described by suppression factors ɛ^{n_i} for charged fermion i, as can arise in Froggatt-Nielsen and extra-dimensional theories of flavor. The corresponding flavor factors in the mirror sector are ɛ^' {n}_i} , so that spontaneous breaking of the parity P arises from a single parameter ɛ'/ɛ, yielding a tightly constrained version of Minimal Mirror Twin Higgs, introduced in our previous paper. Models are studied for simple values of n i , including in particular one with SU(5)-compatibility, that describe the observed fermion mass hierarchy. The entire mirror quark and charged lepton spectrum is broadly predicted in terms of ɛ'/ɛ, as are the mirror QCD scale and the decoupling temperature between the two sectors. Helium-, hydrogen- and neutron-like mirror dark matter candidates are constrained by self-scattering and relic ionization. In each case, the allowed parameter space can be fully probed by proposed direct detection experiments. Correlated predictions are made as well for the Higgs signal strength and the amount of dark radiation.

Mirror Fusion Test Facility: an intermediate device to a mirror fusion reactor

International Nuclear Information System (INIS)

Karpenko, V.N.

1983-01-01

The Mirror Fusion Test Facility (MFTF-B) now under construction at Lawrence Livermore National Laboratory represents more than an order-of-magnitude step from earlier magnetic-mirror experiments toward a future mirror fusion reactor. In fact, when the device begins operating in 1986, the Lawson criteria of ntau = 10 14 cm -3 .s will almost be achieved for D-T equivalent operation, thus signifying scientific breakeven. Major steps have been taken to develop MFTF-B technologies for tandem mirrors. Steady-state, high-field, superconducting magnets at reactor-revelant scales are used in the machine. The 30-s beam pulses, ECRH, and ICRH will also introduce steady-state technologies in those systems

Systems and methods for mirror mounting with minimized distortion

Science.gov (United States)

Antonille, Scott R. (Inventor); Wallace, Thomas E. (Inventor); Content, David A. (Inventor); Wake, Shane W. (Inventor)

2012-01-01

A method for mounting a mirror for use in a telescope includes attaching the mirror to a plurality of adjustable mounts; determining a distortion in the mirror caused by the plurality adjustable mounts, and, if the distortion is determined to be above a predetermined level: adjusting one or more of the adjustable mounts; and determining the distortion in the mirror caused by the adjustable mounts; and in the event the determined distortion is determined to be at or below the predetermined level, rigidizing the adjustable mounts.

The Mirror Neuron System and Action Recognition

Science.gov (United States)

Buccino, Giovanni; Binkofski, Ferdinand; Riggio, Lucia

2004-01-01

Mirror neurons, first described in the rostral part of monkey ventral premotor cortex (area F5), discharge both when the animal performs a goal-directed hand action and when it observes another individual performing the same or a similar action. More recently, in the same area mirror neurons responding to the observation of mouth actions have been…

Mirror neurons: functions, mechanisms and models.

Science.gov (United States)

Oztop, Erhan; Kawato, Mitsuo; Arbib, Michael A

2013-04-12

Mirror neurons for manipulation fire both when the animal manipulates an object in a specific way and when it sees another animal (or the experimenter) perform an action that is more or less similar. Such neurons were originally found in macaque monkeys, in the ventral premotor cortex, area F5 and later also in the inferior parietal lobule. Recent neuroimaging data indicate that the adult human brain is endowed with a "mirror neuron system," putatively containing mirror neurons and other neurons, for matching the observation and execution of actions. Mirror neurons may serve action recognition in monkeys as well as humans, whereas their putative role in imitation and language may be realized in human but not in monkey. This article shows the important role of computational models in providing sufficient and causal explanations for the observed phenomena involving mirror systems and the learning processes which form them, and underlines the need for additional circuitry to lift up the monkey mirror neuron circuit to sustain the posited cognitive functions attributed to the human mirror neuron system. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Acting together in and beyond the mirror neuron system

NARCIS (Netherlands)

Kokal, Idil; Gazzola, Valeria; Keysers, Christian

2009-01-01

Moving a set dinner table often takes two people, and doing so without spilling the glasses requires the close coordination of the two agents' actions. It has been argued that the mirror neuron system may be the key neural locus of such coordination. Instead, here we show that such coordination

A Control and Detecting System of Micro-Near-Infrared Spectrometer Based on a MOEMS Scanning Grating Mirror

Directory of Open Access Journals (Sweden)

Haitao Liu

2018-03-01

Full Text Available Based on the scanning grating mirror we developed, this paper presents a method of the precise control of a scanning grating mirror and of high-speed spectrum data detection. In addition, the system circuit of the scanning grating mirror control and spectrum signal detecting is designed and manufactured in this paper. The mirror control system includes a drive generator module, an amplitude detection module, a feedback control module, and a variable gain amplification (VGA module; the detecting system includes a field programmable gate array (FPGA main control module, a synchronous trigger module, an analog-digital conversion (ADC module, and a universal serial bus (USB interface module. The final results of the experiment show that the control system has successfully realized the precision control of the swing of the scanning grating mirror and that the detecting system has successfully realized the high-speed acquisition and transmission of the spectral signal and the angle signals. The spectrum has been reconstructed according to the mathematical relationship between the wavelength λ and the angle β of the mirror. The resolution of the spectrometer reaches 10 nm in the wavelength range of 800–1800 nm, the signal-to-noise ratio (SNR of the spectrometer is 4562 at full scale, the spectrum data drift is 0.9% in 24 h, and the precision of the closed loop control is 0.06%.

Mirroring

DEFF Research Database (Denmark)

Wegener, Charlotte; Wegener, Gregers

2016-01-01

and metaphorical value of mirroring for creativity theory across two different research fields — neuroscience and learning. We engage in a mutual (possibly creative) exploration of mirroring from ‘mirror neurons’ to mirroring in social learning theory. One of the most fascinating aspects of mirroring...... as a neurobiological and as a learning phenomenon is that it points to the embodied and unconscious aspects of social interaction. Thus, mirroring should not be reduced to the non-creative, mechanical repetition of the original, outstanding creativity. To mirror is a human capability built into our capacity to create......Most definitions of creativity emphasise originality. The creative product is recognised as distinct from other products and the creative person as someone who stands out from the crowd. What tend to be overlooked are acts of mirroring as a crucial element of the creative process. The human ability...

Improved Mirror Source Method in Roomacoustics

Science.gov (United States)

Mechel, F. P.

2002-10-01

Most authors in room acoustics qualify the mirror source method (MS-method) as the only exact method to evaluate sound fields in auditoria. But evidently nobody applies it. The reason for this discrepancy is the abundantly high numbers of needed mirror sources which are reported in the literature, although such estimations of needed numbers of mirror sources mostly are used for the justification of more or less heuristic modifications of the MS-method. The present, intentionally tutorial article accentuates the analytical foundations of the MS-method whereby the number of needed mirror sources is reduced already. Further, the task of field evaluation in three-dimensional spaces is reduced to a sequence of tasks in two-dimensional room edges. This not only allows the use of easier geometrical computations in two dimensions, but also the sound field in corner areas can be represented by a single (directional) source sitting on the corner line, so that only this "corner source" must be mirror-reflected in the further process. This procedure gives a drastic reduction of the number of needed equivalent sources. Finally, the traditional MS-method is not applicable in rooms with convex corners (the angle between the corner flanks, measured on the room side, exceeds 180°). In such cases, the MS-method is combined below with the second principle of superposition(PSP). It reduces the scattering task at convex corners to two sub-tasks between one flank and the median plane of the room wedge, i.e., always in concave corner areas where the MS-method can be applied.

MULTI-LAYER MIRROR FOR RADIATION IN THE XUV WAVELENGHT RANGE AND METHOD FOR MANUFACTURE THEREOF

NARCIS (Netherlands)

Bijkerk, Frederik; Louis, Eric; Kessels, M.J.H.; Verhoeven, Jan; Den Hartog, Harmen Markus Johannes

2002-01-01

Multi-layer mirror for radiation with a wavelength in the wavelength range between 0.1 nm and 30 nm (the so-called XUV range), comprising a stack of thin films substantially comprising scattering particles which scatter the radiation, which thin films are separated by separating layers with a

Tentative investigation on neutron mirror fabrication with electroless nickel plating

International Nuclear Information System (INIS)

Guo, Jiang; Morita, Shin-ya; Yamagata, Yutaka; Takeda, Shin; Kato, Jun-ichi; Hino, Masahiro; Furusaka, Michihiro

2013-01-01

Neutron optics becomes highly required due to the rapid development of neutron technology. In this paper, we attempt to fabricate the neutron mirror by using a metal substrate made of electroless nickel plating to take place of glass concerning about mirror's optical performance and manufacturing method. A new manufacture process chain of neutron mirror is proposed by following the steps of fast milling and precision cutting of aluminium/stainless, electroless nickel plating, ultra-precision cutting by diamond tools, super-smooth polishing and super mirror coating to obtain high form accuracy and good surface roughness time-efficiently. Some tentative investigations are carried out. A workpiece (□ 50 x 50 mm 2 ) with flat surface made of electroless nickel plating is machined by ultra-precision cutting and polishing. The surface roughness with 0.728 nm rms (0.588 nm Ra) is acquired. According to results of reflectometry, the neutron beam can be reflected effectively with high intensity and little scattering. (author)

Status of the Tandem Mirror Experiment-Upgrade (TMX-U) diagnostic system

International Nuclear Information System (INIS)

Coutts, G.W.; Coffield, F.E.; Hornady, R.S.

1983-01-01

This paper presents the current status of the Tandem Mirror Experiment-Upgrade (TMX-U) diagnostics system. For the initial instruments active on TMX-U, the expansions or upgrades that have been implemented are outlined. For the newly added systems, more implementation details are presented

Research on large-aperture primary mirror supporting way of vehicle-mounted laser communication system

Science.gov (United States)

Meng, Lixin; Meng, Lingchen; Zhang, Yiqun; Zhang, Lizhong; Liu, Ming; Li, Xiaoming

2018-01-01

In the satellite to earth laser communication link, large-aperture ground laser communication terminals usually are used in order to realize the requirement of high rate and long distance communication and restrain the power fluctuation by atmospheric scintillation. With the increasing of the laser communication terminal caliber, the primary mirror weight should also be increased, and selfweight, thermal deformation and environment will affect the surface accuracy of the primary mirror surface. A high precision vehicular laser communication telescope unit with an effective aperture of 600mm was considered in this paper. The primary mirror is positioned with center hole, which back is supported by 9 floats and the side is supported by a mercury band. The secondary mirror adopts a spherical adjusting mechanism. Through simulation analysis, the system wave difference is better than λ/20 when the primary mirror is in different dip angle, which meets the requirements of laser communication.

Proposal of a wide-band mirror polarizer of slow neutrons at a pulsed neutron source

International Nuclear Information System (INIS)

Nikitenko, Yu.V.; Ostanevich, Yu.M.

1993-01-01

The new type of wide-band mirror-based neutron polarizer, which is to be operated at a pulsed neutron source, is suggested. The idea is to use a movable polarizing mirror system, which, with the incoming beam monochromatized by the time-of-flight, would allow one to tune glancing angles in time so that the total reflection condition is always fulfilled only for one of the two neutron spin eigenstates. Estimates show that with the pulsed reactor IBR-2 such a polarizer allows one to build a small angle neutron scattering instrument capable of effectively using the wavelength band from 2 A with a rather high luminosity (time-averaged flux at sample position being up to 10 7 n/s/cm -2 ). (orig.)

A study on multi-point gravity compensation of mirror bending system

International Nuclear Information System (INIS)

Sun Fuquan; Fu Yuan; Zhu Wanqian; Xue Song

2011-01-01

The sag of mirror due to gravity induces unacceptable slope errors in beamline mirror-bending system of a synchrotron radiation facility, and approaches must be found to eliminate the unwanted gravity effect. According to the beam bending theory, the multi-point gravity compensation method is applicable. Taking an example of the bent collimating mirror for the XAFS beam-line (BL14W) at Shanghai Synchrotron Radiation Facility (SSRF), the best position and value of the equilibrant were calculated through minimizing the gravity effect. With two, three and four points gravity compensation, slope errors were 0.179, 0.067 and 0.032 μrad,respectively, i.e.the multi-point gravity compensation is better than the two-point gravity compensation, which is used for the Phase I beamlines of SSRF. The four-point gravity compensation method reduces more slope error and stress due to four support points. (authors)

Design Study for Direction Variable Compton Scattering Gamma Ray

Science.gov (United States)

Kii, T.; Omer, M.; Negm, H.; Choi, Y. W.; Kinjo, R.; Yoshida, K.; Konstantin, T.; Kimura, N.; Ishida, K.; Imon, H.; Shibata, M.; Shimahashi, K.; Komai, T.; Okumura, K.; Zen, H.; Masuda, K.; Hori, T.; Ohgaki, H.

2013-03-01

A monochromatic gamma ray beam is attractive for isotope-specific material/medical imaging or non-destructive inspection. A laser Compton scattering (LCS) gamma ray source which is based on the backward Compton scattering of laser light on high-energy electrons can generate energy variable quasi-monochromatic gamma ray. Due to the principle of the LCS gamma ray, the direction of the gamma beam is limited to the direction of the high-energy electrons. Then the target object is placed on the beam axis, and is usually moved if spatial scanning is required. In this work, we proposed an electron beam transport system consisting of four bending magnets which can stick the collision point and control the electron beam direction, and a laser system consisting of a spheroidal mirror and a parabolic mirror which can also stick the collision point. Then the collision point can be placed on one focus of the spheroid. Thus gamma ray direction and collision angle between the electron beam and the laser beam can be easily controlled. As the results, travelling direction of the LCS gamma ray can be controlled under the limitation of the beam transport system, energy of the gamma ray can be controlled by controlling incident angle of the colliding beams, and energy spread can be controlled by changing the divergence of the laser beam.

SCATTERING FROM RAMIFIED POLYMERIC SYSTEMS

Directory of Open Access Journals (Sweden)

M.Benhamou

2004-01-01

Full Text Available Here, of great interest to us is a quantitative study of the scattering properties from ramified polymeric systems of arbitrary topology. We consider three types of systems, namely ramified polymers in solution, ramified polymer blends, or ternary mixtures made of two ramified polymers of different chemical nature immersed in a good solvent. To achieve the goal of the study, use is made of the Random Phase Approximation. First we determine the exact expression of the form factor of an ideal ramified polymer of any topology, from which we extract the exact expression of its gyration radius. Using the classical Zimm's formulae and the exact form factor, we determine all scattering properties of these three types of ramified polymeric systems. The main conclusion is that ramification of the chains induces drastic changes of the scattering properties.

Mirror, mirror on the wall

CERN Multimedia

2005-01-01

RICH 2, one of the two Ring Imaging Cherenkov detectors of the LHCb experiment, is being prepared to join the other detector elements ready for the first proton-proton collisions at LHC. The mirrors of the RICH2 detector are meticulously assembled in a clean room.In a large dark room, men in white move around an immense structure some 7 metres high, 10 metres wide and nearly 2.5 metres deep. Apparently effortlessly, they are installing the two large high-precision spherical mirrors. These mirrors will focus Cherenkov light, created by the charged particles that will traverse this detector, onto the photon detectors. Each spherical mirror wall is made up of facets like a fly's eye. Twenty-eight individual thin glass mirrors will all point to the same point in space to within a few micro-radians. The development of these mirrors has been technically demanding : Ideally they should be massless, sturdy, precise and have high reflectivity. In practice, though not massless, they are made from a mere 6 mm thin gl...

Magnet system of the ''AMBAL'' experimental trap with ambipolar mirrors

International Nuclear Information System (INIS)

Dimov, G.I.; Lysyanskij, P.B.; Tadber, M.V.; Timoshin, I.Ya.; Shrajner, K.K.

1982-01-01

A magnet system of the ''AMBAL'' ambipolar trap under construction is described. The trap magnetic field configuration, geometry of the main coils and diagram of the whole device magnet system are outlined. Drift surface cross sections in the equatorial plane of the ring mirror device, in the median plane and at different distances from the trap median plane are presented. The magnet system design is described in brief

Neutron scattering. Experiment manuals

Energy Technology Data Exchange (ETDEWEB)

Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

2010-07-01

The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

Neutron scattering. Experiment manuals

International Nuclear Information System (INIS)

Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

2010-01-01

The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

Imaging moving objects from multiply scattered waves and multiple sensors

International Nuclear Information System (INIS)

Miranda, Analee; Cheney, Margaret

2013-01-01

In this paper, we develop a linearized imaging theory that combines the spatial, temporal and spectral components of multiply scattered waves as they scatter from moving objects. In particular, we consider the case of multiple fixed sensors transmitting and receiving information from multiply scattered waves. We use a priori information about the multipath background. We use a simple model for multiple scattering, namely scattering from a fixed, perfectly reflecting (mirror) plane. We base our image reconstruction and velocity estimation technique on a modification of a filtered backprojection method that produces a phase-space image. We plot examples of point-spread functions for different geometries and waveforms, and from these plots, we estimate the resolution in space and velocity. Through this analysis, we are able to identify how the imaging system depends on parameters such as bandwidth and number of sensors. We ultimately show that enhanced phase-space resolution for a distribution of moving and stationary targets in a multipath environment may be achieved using multiple sensors. (paper)

Augmented Mirror: Interactive Augmented Reality System Based on Kinect

OpenAIRE

Vera , Lucía; Gimeno , Jesús; Coma , Inmaculada; Fernández , Marcos

2011-01-01

Part 1: Long and Short Papers; International audience; In this paper we present a virtual character controlled by an actor in real time, who talks with an audience through an augmented mirror. The application, which integrates video images, the avatar and other virtual objects within an Augmented Reality system, has been implemented using a mixture of technologies: two kinect systems for motion capture, depth map and real images, a gyroscope to detect head movements, and control algorithms to...

The spinning Kerr-black-hole-mirror bomb: A lower bound on the radius of the reflecting mirror

Science.gov (United States)

Hod, Shahar

2016-10-01

The intriguing superradiant amplification phenomenon allows an orbiting scalar field to extract rotational energy from a spinning Kerr black hole. Interestingly, the energy extraction rate can grow exponentially in time if the black-hole-field system is placed inside a reflecting mirror which prevents the field from radiating its energy to infinity. This composed Kerr-black-hole-scalar-field-mirror system, first designed by Press and Teukolsky, has attracted the attention of physicists over the last four decades. Previous numerical studies of this spinning black-hole bomb have revealed the interesting fact that the superradiant instability shuts down if the reflecting mirror is placed too close to the black-hole horizon. In the present study we use analytical techniques to explore the superradiant instability regime of this composed Kerr-black-hole-linearized-scalar-field-mirror system. In particular, it is proved that the lower bound rm/r+ >1/2 (√{ 1 +8M/r- } - 1) provides a necessary condition for the development of the exponentially growing superradiant instabilities in this composed physical system, where rm is the radius of the confining mirror and r± are the horizon radii of the spinning Kerr black hole. We further show that, in the linearized regime, this analytically derived lower bound on the radius of the confining mirror agrees with direct numerical computations of the superradiant instability spectrum which characterizes the spinning black-hole-mirror bomb.

Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal.

Science.gov (United States)

Corballis, Michael C

2018-01-01

Mirror-image confusions are common, especially in children and in some cases of neurological impairment. They can be a special impediment in activities such as reading and writing directional scripts, where mirror-image patterns (such as b and d ) must be distinguished. Treating mirror images as equivalent, though, can also be adaptive in the natural world, which carries no systematic left-right bias and where the same object or event can appear in opposite viewpoints. Mirror-image equivalence and confusion are natural consequences of a bilaterally symmetrical brain. In the course of learning, mirror-image equivalence may be established through a process of symmetrization, achieved through homotopic interhemispheric exchange in the formation of memory circuits. Such circuits would not distinguish between mirror images. Learning to discriminate mirror-image discriminations may depend either on existing brain asymmetries, or on extensive learning overriding the symmetrization process. The balance between mirror-image equivalence and mirror-image discrimination may nevertheless be precarious, with spontaneous confusions or reversals, such as mirror writing, sometimes appearing naturally or as a manifestation of conditions like dyslexia.

Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal

Directory of Open Access Journals (Sweden)

Michael C. Corballis

2018-04-01

Full Text Available Mirror-image confusions are common, especially in children and in some cases of neurological impairment. They can be a special impediment in activities such as reading and writing directional scripts, where mirror-image patterns (such as b and d must be distinguished. Treating mirror images as equivalent, though, can also be adaptive in the natural world, which carries no systematic left-right bias and where the same object or event can appear in opposite viewpoints. Mirror-image equivalence and confusion are natural consequences of a bilaterally symmetrical brain. In the course of learning, mirror-image equivalence may be established through a process of symmetrization, achieved through homotopic interhemispheric exchange in the formation of memory circuits. Such circuits would not distinguish between mirror images. Learning to discriminate mirror-image discriminations may depend either on existing brain asymmetries, or on extensive learning overriding the symmetrization process. The balance between mirror-image equivalence and mirror-image discrimination may nevertheless be precarious, with spontaneous confusions or reversals, such as mirror writing, sometimes appearing naturally or as a manifestation of conditions like dyslexia.

Multilayer active shell mirrors for space telescopes

Science.gov (United States)

Steeves, John; Jackson, Kathryn; Pellegrino, Sergio; Redding, David; Wallace, J. Kent; Bradford, Samuel Case; Barbee, Troy

2016-07-01

A novel active mirror technology based on carbon fiber reinforced polymer (CFRP) substrates and replication techniques has been developed. Multiple additional layers are implemented into the design serving various functions. Nanolaminate metal films are used to provide a high quality reflective front surface. A backing layer of thin active material is implemented to provide the surface-parallel actuation scheme. Printed electronics are used to create a custom electrode pattern and flexible routing layer. Mirrors of this design are thin (traditional optics. Such mirrors could be used as lightweight primaries for small CubeSat-based telescopes or as meter-class segments for future large aperture observatories. Multiple mirrors can be produced under identical conditions enabling a substantial reduction in manufacturing cost and complexity. An overview of the mirror design and manufacturing processes is presented. Predictions on the actuation performance have been made through finite element simulations demonstrating correctabilities on the order of 250-300× for astigmatic modes with only 41 independent actuators. A description of the custom metrology system used to characterize the active mirrors is also presented. The system is based on a Reverse Hartmann test and can accommodate extremely large deviations in mirror figure (> 100 μm PV) down to sub-micron precision. The system has been validated against several traditional techniques including photogrammetry and interferometry. The mirror performance has been characterized using this system, as well as closed-loop figure correction experiments on 150 mm dia. prototypes. The mirrors have demonstrated post-correction figure accuracies of 200 nm RMS (two dead actuators limiting performance).

View-Invariant Visuomotor Processing in Computational Mirror Neuron System for Humanoid

Science.gov (United States)

Dawood, Farhan; Loo, Chu Kiong

2016-01-01

Mirror neurons are visuo-motor neurons found in primates and thought to be significant for imitation learning. The proposition that mirror neurons result from associative learning while the neonate observes his own actions has received noteworthy empirical support. Self-exploration is regarded as a procedure by which infants become perceptually observant to their own body and engage in a perceptual communication with themselves. We assume that crude sense of self is the prerequisite for social interaction. However, the contribution of mirror neurons in encoding the perspective from which the motor acts of others are seen have not been addressed in relation to humanoid robots. In this paper we present a computational model for development of mirror neuron system for humanoid based on the hypothesis that infants acquire MNS by sensorimotor associative learning through self-exploration capable of sustaining early imitation skills. The purpose of our proposed model is to take into account the view-dependency of neurons as a probable outcome of the associative connectivity between motor and visual information. In our experiment, a humanoid robot stands in front of a mirror (represented through self-image using camera) in order to obtain the associative relationship between his own motor generated actions and his own visual body-image. In the learning process the network first forms mapping from each motor representation onto visual representation from the self-exploratory perspective. Afterwards, the representation of the motor commands is learned to be associated with all possible visual perspectives. The complete architecture was evaluated by simulation experiments performed on DARwIn-OP humanoid robot. PMID:26998923

View-Invariant Visuomotor Processing in Computational Mirror Neuron System for Humanoid.

Science.gov (United States)

Dawood, Farhan; Loo, Chu Kiong

2016-01-01

Mirror neurons are visuo-motor neurons found in primates and thought to be significant for imitation learning. The proposition that mirror neurons result from associative learning while the neonate observes his own actions has received noteworthy empirical support. Self-exploration is regarded as a procedure by which infants become perceptually observant to their own body and engage in a perceptual communication with themselves. We assume that crude sense of self is the prerequisite for social interaction. However, the contribution of mirror neurons in encoding the perspective from which the motor acts of others are seen have not been addressed in relation to humanoid robots. In this paper we present a computational model for development of mirror neuron system for humanoid based on the hypothesis that infants acquire MNS by sensorimotor associative learning through self-exploration capable of sustaining early imitation skills. The purpose of our proposed model is to take into account the view-dependency of neurons as a probable outcome of the associative connectivity between motor and visual information. In our experiment, a humanoid robot stands in front of a mirror (represented through self-image using camera) in order to obtain the associative relationship between his own motor generated actions and his own visual body-image. In the learning process the network first forms mapping from each motor representation onto visual representation from the self-exploratory perspective. Afterwards, the representation of the motor commands is learned to be associated with all possible visual perspectives. The complete architecture was evaluated by simulation experiments performed on DARwIn-OP humanoid robot.

View-Invariant Visuomotor Processing in Computational Mirror Neuron System for Humanoid.

Directory of Open Access Journals (Sweden)

Farhan Dawood

Full Text Available Mirror neurons are visuo-motor neurons found in primates and thought to be significant for imitation learning. The proposition that mirror neurons result from associative learning while the neonate observes his own actions has received noteworthy empirical support. Self-exploration is regarded as a procedure by which infants become perceptually observant to their own body and engage in a perceptual communication with themselves. We assume that crude sense of self is the prerequisite for social interaction. However, the contribution of mirror neurons in encoding the perspective from which the motor acts of others are seen have not been addressed in relation to humanoid robots. In this paper we present a computational model for development of mirror neuron system for humanoid based on the hypothesis that infants acquire MNS by sensorimotor associative learning through self-exploration capable of sustaining early imitation skills. The purpose of our proposed model is to take into account the view-dependency of neurons as a probable outcome of the associative connectivity between motor and visual information. In our experiment, a humanoid robot stands in front of a mirror (represented through self-image using camera in order to obtain the associative relationship between his own motor generated actions and his own visual body-image. In the learning process the network first forms mapping from each motor representation onto visual representation from the self-exploratory perspective. Afterwards, the representation of the motor commands is learned to be associated with all possible visual perspectives. The complete architecture was evaluated by simulation experiments performed on DARwIn-OP humanoid robot.

Viability study of porous silicon photonic mirrors as secondary reflectors for solar concentration systems

Energy Technology Data Exchange (ETDEWEB)

de la Mora, M.B.; Jaramillo, O.A.; Nava, R.; Tagueena-Martinez, J. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, A. P. 34, 62580 Temixco, Morelos (Mexico); del Rio, J.A. [Centro Morelense de Innovacion y Transferencia Tecnologica, CCyTEM Camino Temixco a Emiliano Zapata, Km 0.3, Colonia Emiliano Zapata, 62760 Morelos (Mexico)

2009-08-15

In this paper we report the viability of using porous silicon photonic mirrors (PSPM) as secondary reflectors in solar concentration systems. The PSPM were fabricated with nanostructured porous silicon to reflect light from the visible range to the near infrared region (500-2500 nm), although this range could be tuned for specific wavelength applications. Our PSPM are multilayers of two alternated refractive indexes (1.5 and 2.0), where the condition of a quarter wavelength in the optical path was imposed. The PSPM were exposed to high radiation in a solar concentrator equipment. As a result, we observed a significant degradation of the mirrors at an approximated temperature of 900 C. In order to analyze the origin of the degradation of PSPM, we model the samples with a non-linear optical approach and study the effect of a temperature increase. Those theoretical and experimental studies allow us to conclude that the main phenomenon involved in the breakdown of the photonic mirrors is of thermal origin, produced by heterogeneous expansion of each layer. Our next step was to introduce a cooling system into the solar concentrator to keep the mirrors at approximately 70 C, with very good results. As a conclusion we propose the use of PSPM as selective secondary mirrors in solar concentration devices using temperature control to avoid thermal degradation. (author)

Mirror Neurons and Mirror-Touch Synesthesia.

Science.gov (United States)

Linkovski, Omer; Katzin, Naama; Salti, Moti

2016-05-30

Since mirror neurons were introduced to the neuroscientific community more than 20 years ago, they have become an elegant and intuitive account for different cognitive mechanisms (e.g., empathy, goal understanding) and conditions (e.g., autism spectrum disorders). Recently, mirror neurons were suggested to be the mechanism underlying a specific type of synesthesia. Mirror-touch synesthesia is a phenomenon in which individuals experience somatosensory sensations when seeing someone else being touched. Appealing as it is, careful delineation is required when applying this mechanism. Using the mirror-touch synesthesia case, we put forward theoretical and methodological issues that should be addressed before relying on the mirror-neurons account. © The Author(s) 2016.

Lessons Learned During Cryogenic Optical Testing of the Advanced Mirror System Demonstrators (AMSDs)

Science.gov (United States)

Hadaway, James; Reardon, Patrick; Geary, Joseph; Robinson, Brian; Stahl, Philip; Eng, Ron; Kegley, Jeff

2004-01-01

Optical testing in a cryogenic environment presents a host of challenges above and beyond those encountered during room temperature testing. The Advanced Mirror System Demonstrators (AMSDs) are 1.4 m diameter, ultra light-weight (mA2), off-axis parabolic segments. They are required to have 250 nm PV & 50 nm RMS surface figure error or less at 35 K. An optical testing system, consisting of an Instantaneous Phase Interferometer (PI), a diffractive null corrector (DNC), and an Absolute Distance Meter (ADM), was used to measure the surface figure & radius-of-curvature of these mirrors at the operational temperature within the X-Ray Calibration Facility (XRCF) at Marshall Space Flight Center (MSFC). The Ah4SD program was designed to improve the technology related to the design, fabrication, & testing of such mirrors in support of NASA s James Webb Space Telescope (JWST). This paper will describe the lessons learned during preparation & cryogenic testing of the AMSDs.

Operation of the cryogenic system for the Mirror Fusion Test Facility

International Nuclear Information System (INIS)

Chronis, W.C.; Slack, D.S.

1987-01-01

The cryogenic system for the Mirror Fusion Test Facility (MFTF) at Lawrence Livermore National Laboratory (LLNL) was designed to cool the entire MFTF-B system from ambient to operating temperature in less than 10 days. The system was successfully operated in the recent plant and capital equipment (PACE) acceptance tests, and results from these tests helped us correct problem areas and improve the system

Sensorimotor learning and the ontogeny of the mirror neuron system.

Science.gov (United States)

Catmur, Caroline

2013-04-12

Mirror neurons, which have now been found in the human and songbird as well as the macaque, respond to both the observation and the performance of the same action. It has been suggested that their matching response properties have evolved as an adaptation for action understanding; alternatively, these properties may arise through sensorimotor experience. Here I review mirror neuron response characteristics from the perspective of ontogeny; I discuss the limited evidence for mirror neurons in early development; and I describe the growing body of evidence suggesting that mirror neuron responses can be modified through experience, and that sensorimotor experience is the critical type of experience for producing mirror neuron responses. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Laser beam alignment and profilometry using diagnostic fluorescent safety mirrors

Science.gov (United States)

Lizotte, Todd E.

2011-03-01

There are a wide range of laser beam delivery systems in use for various purposes; including industrial and medical applications. Virtually all such beam delivery systems for practical purposes employ optical systems comprised of mirrors and lenses to shape, focus and guide the laser beam down to the material being processed. The goal of the laser beam delivery is to set the optimum parameters and to "fold" the beam path to reduce the mechanical length of the optical system, thereby allowing a physically compact system. In many cases, even a compact system can incorporate upwards of six mirrors and a comparable number of lenses all needing alignment so they are collinear. One of the major requirements for use of such systems in industry is a method of safe alignment. The alignment process requires that the aligner determine where the beam strikes each element. The aligner should also preferably be able to determine the shape or pattern of the laser beam at that point and its relative power. These alignments are further compounded in that the laser beams generated are not visible to the unaided human eye. Such beams are also often of relatively high power levels, and are thereby a significant hazard to the eyes of the aligner. Obvious an invisible beam makes it nearly impossible to align laser system without some form of optical assistance. The predominant method of visually aligning the laser beam delivery is the use of thermal paper, paper cards or fluorescing card material. The use of paper products which have limited power handling capability or coated plastics can produce significant debris and contaminants within the beam line that ultimately damage the optics. The use of the cards can also create significant laser light scatter jeopardizing the safety of the person aligning the system. This paper covers a new safety mirror design for use with at various UV and Near IR wavelengths (193 nm to 1064 nm) within laser beam delivery systems and how its use can

Scattering (stochastic) recoupling of a coupled ten-stripe AlGaAs-GaAs-InGaAs quantum-well heterostructure laser

Science.gov (United States)

Kellogg, D. A.; Holonyak, N.

2001-04-01

Data are presented on coupled ten-stripe AlGaAs-GaAs-InGaAs quantum well heterostructure (QWH) lasers recoupled stochastically at the cleaved end mirrors. Recoupling of neighboring elements of a ten-stripe laser is accomplished by the scattering (random feedback) afforded by applying ˜10-μm-diam Al powder or 0.3 μm α-Al2O3 polishing compound in microscopy immersion oil or in epoxy at the cleaved ends (mirrors). Data on QWH samples with the end mirrors coated with the scatterer (Al or Al2O3 powder in "liquid") exhibit spectral and far-field broadening, as well as increased laser threshold because of the reduced cavity Q. Single mode operation is possible with the conventional evanescent wave coupling of the ten-stripe QWH and is destroyed, even the laser operation itself, with the scattering recoupling (dephasing) at the end mirrors, which is reversible (removable). The narrow ten-stripe QWH laser with strong end-mirror scattering, a long amplifier with random feedback, indicates that a photopumped III-V or II-VI powder (a random "wall" cavity) has little or no merit.

Mirror neurons and imitation: a computationally guided review.

Science.gov (United States)

Oztop, Erhan; Kawato, Mitsuo; Arbib, Michael

2006-04-01

Neurophysiology reveals the properties of individual mirror neurons in the macaque while brain imaging reveals the presence of 'mirror systems' (not individual neurons) in the human. Current conceptual models attribute high level functions such as action understanding, imitation, and language to mirror neurons. However, only the first of these three functions is well-developed in monkeys. We thus distinguish current opinions (conceptual models) on mirror neuron function from more detailed computational models. We assess the strengths and weaknesses of current computational models in addressing the data and speculations on mirror neurons (macaque) and mirror systems (human). In particular, our mirror neuron system (MNS), mental state inference (MSI) and modular selection and identification for control (MOSAIC) models are analyzed in more detail. Conceptual models often overlook the computational requirements for posited functions, while too many computational models adopt the erroneous hypothesis that mirror neurons are interchangeable with imitation ability. Our meta-analysis underlines the gap between conceptual and computational models and points out the research effort required from both sides to reduce this gap.

Is the human mirror neuron system plastic? Evidence from a transcranial magnetic stimulation study.

Science.gov (United States)

Mehta, Urvakhsh Meherwan; Waghmare, Avinash V; Thirthalli, Jagadisha; Venkatasubramanian, Ganesan; Gangadhar, Bangalore N

2015-10-01

Virtual lesions in the mirror neuron network using inhibitory low-frequency (1Hz) transcranial magnetic stimulation (TMS) have been employed to understand its spatio-functional properties. However, no studies have examined the influence of neuro-enhancement by using excitatory high-frequency (20Hz) repetitive transcranial magnetic stimulation (HF-rTMS) on these networks. We used three forms of TMS stimulation (HF-rTMS, single and paired pulse) to investigate whether the mirror neuron system facilitates the motor system during goal-directed action observation relative to inanimate motion (motor resonance), a marker of putative mirror neuron activity. 31 healthy individuals were randomized to receive single-sessions of true or sham HF-rTMS delivered to the left inferior frontal gyrus - a component of the human mirror system. Motor resonance was assessed before and after HF-rTMS using three TMS cortical reactivity paradigms: (a) 120% of resting motor threshold (RMT), (b) stimulus intensity set to evoke motor evoked potential of 1-millivolt amplitude (SI1mV) and (c) a short latency paired pulse paradigm. Two-way RMANOVA showed a significant group (true versus sham) X occasion (pre- and post-HF-rTMS motor resonance) interaction effect for SI1mV [F(df)=6.26 (1, 29), p=0.018] and 120% RMT stimuli [F(df)=7.01 (1, 29), p=0.013] indicating greater enhancement of motor resonance in the true HF-rTMS group than the sham-group. This suggests that HF-rTMS could adaptively modulate properties of the mirror neuron system. This neuro-enhancement effect is a preliminary step that can open translational avenues for novel brain stimulation therapeutics targeting social-cognition deficits in schizophrenia and autism. Copyright © 2015 Elsevier B.V. All rights reserved.

The Mirror Neuron System: Grasping Others' Actions from Birth?

Science.gov (United States)

Lepage, Jean-Francois; Theoret, Hugo

2007-01-01

In the adult human brain, the presence of a system matching the observation and the execution of actions is well established. This mechanism is thought to rely primarily on the contribution of so-called "mirror neurons", cells that are active when a specific gesture is executed as well as when it is seen or heard. Despite the wealth of evidence…

Internal stray radiation measurement for cryogenic infrared imaging systems using a spherical mirror.

Science.gov (United States)

Tian, Qijie; Chang, Songtao; He, Fengyun; Li, Zhou; Qiao, Yanfeng

2017-06-10

Internal stray radiation is a key factor that influences infrared imaging systems, and its suppression level is an important criterion to evaluate system performance, especially for cryogenic infrared imaging systems, which are highly sensitive to thermal sources. In order to achieve accurate measurement for internal stray radiation, an approach is proposed, which is based on radiometric calibration using a spherical mirror. First of all, the theory of spherical mirror design is introduced. Then, the calibration formula considering the integration time is presented. Following this, the details regarding the measurement method are presented. By placing a spherical mirror in front of the infrared detector, the influence of internal factors of the detector on system output can be obtained. According to the calibration results of the infrared imaging system, the output caused by internal stray radiation can be acquired. Finally, several experiments are performed in a chamber with controllable inside temperatures to validate the theory proposed in this paper. Experimental results show that the measurement results are in good accordance with the theoretical analysis, and demonstrate that the proposed theories are valid and can be employed in practical applications. The proposed method can achieve accurate measurement for internal stray radiation at arbitrary integration time and ambient temperatures. The measurement result can be used to evaluate whether the suppression level meets the system requirement.

Tandem-Mirror Experiment-Upgrade neutral pressure measurement diagnostic systems

International Nuclear Information System (INIS)

Pickles, W.L.; Allen, S.L.; Hill, D.N.; Hunt, A.L.; Simonen, T.C.

1985-01-01

The Tandem-Mirror Experiment-Upgrade (TMX-U) has a large and complex system of Bayard--Alpert, magnetron, and Penning gauges, in addition to mass spectrometers (RGA), all of which measure neutral pressures in the many internal regions of TMX-U. These pressure measurements are used as part of the confinement physics data base as well as for management of the TMX-U vacuum system. Dynamic pressures are modeled by a coupled-volumes simulation code, which includes wall reflux, getter pumping, and plasma pumping

Preliminary Calculations of Shutdown Dose Rate for the CTS Diagnostics System

DEFF Research Database (Denmark)

Klinkby, Esben Bryndt; Nonbøl, Erik; Lauritzen, Bent

2015-01-01

DTU and IST 2 are partners in the design of a collective Thomson Scattering (CTS) diagnostics for ITER through a contract with F4E. The CTS diagnostic utilizes probing radiation of ~60 GHz emitted into the plasma and, using a mirror, collects the scattered radiation by an array of receivers. Having...... on supplying input which affect the system design. Examples include: - Heatloads on plasma facing mirrors and preliminary stress and thermal analysis - Port plug cooling requirements and it's dependence on system design (in particular blanket cut-out) - Shutdown dose-rate calculations (relative analysis...

Position control of ECRH launcher mirrors by laser speckle sensor

International Nuclear Information System (INIS)

Michelsen, Poul K.; Bindslev, Henrik; Hansen, Rene Skov; Hanson, Steen G.

2003-01-01

The planned ECRH system for JET included several fixed and steerable mirrors some of which should have been fixed to the building structure and some to the JET vessel structure. A similar system may be anticipated for ITER and for other fusion devices in the future. In order to have high reproducibility of the ECRH beam direction, it is necessary to know the exact positions of the mirrors. This is not a trivial problem because of thermal expansion of the vessel structures and of the launcher itself and of its support structure, the mechanical load on mirrors and support structures, and the accessibility to the various mirrors. We suggest to use a combination of infrared diagnostic of beam spot positions and a new technique published recently, which is based on a non-contact laser speckle sensor for measuring one- and two-dimensional angular displacement. The method is based on Fourier transforming the scattered field from a single laser beam that illuminates the target. The angular distribution of the light field at the target is linearly mapped onto an array image sensor placed in the Fourier plane. Measuring the displacement of this so-called speckle pattern facilitates the determination of the mirror orientation. Transverse target movement can be measured by observing the speckle movement in the image plane of the object. No special surface treatment is required for surfaces having irregularities of the order of or larger than the wavelength of the incident light. For the JET ECRH launcher it is mainly for the last mirror pointing towards the plasma where the technique may be useful. This mirror has to be steerable in order to reflect the microwave beam in the correct direction towards the plasma. Maximum performance of the microwave heating requires that the beam hits this mirror at its centre and that the mirror is turned in the correct angle. Inaccuracies in the positioning of the pull rods for controlling the mirror turning and thermal effects makes it

The W. M. Keck Telescope segmented primary mirror active control system software

Energy Technology Data Exchange (ETDEWEB)

Cohen, R.W. (Lawrence Berkeley Lab., CA (USA) California Association for Research in Astronomy, Kamuela, HI (USA)); Andreae, S.; Biocca, A.K.; Jared, R.C.; Llacer, J.; Meng, J.D.; Minor, R.H.; Orayani, M. (Lawrence Berkeley Lab., CA (USA))

1989-07-01

The active control system (ACS) uses both parallel and distributed processing techniques to measure and control the positions of the 36 segments of the Keck Observatory Telescope primary mirror. The main function of the software is to maintain the mirror figure; to accomplish this goal the software uses a predictive, feed-forward'' mechanism which effectively increases the system bandwidth for the most important sources of perturbation. The software executes on a set of twelve 68000-family processors under the supervision of a VAX workstation. An array of nine parallel I/O processors collect and process data from 168 displacement sensors and transmit motion commands to 108 actuators. Three additional processors simultaneously compute actuator commands, monitor system performance, compute sensor control parameters and communicate with other observatory computers. The software is highly optimized for speed. 6 refs., 7 figs.

A Novel Mirror-Aided Non-imaging Receiver for Indoor 2x2 MIMO Visible Light Communication Systems

KAUST Repository

Park, Kihong

2017-06-07

Indoor visible light communication (VLC) systems are now possible because of advances in light emitting diode and laser diode technologies. These lighting technologies provide the foundation for multiple-input multiple-output (MIMO) data transmission through visible light. However, the channel matrix can be strongly correlated in indoor MIMO-VLC systems, preventing parallel data streams from being decoded. Here, in $2\\\\times 2$ MIMO-VLC systems, we describe a mirror diversity receiver (MDR) design that reduces the channel correlation by both blocking the reception of light from one specific direction and improving the channel gain from light from another direction by utilizing a double-sided mirror deployed between the receiver\\'s photodetectors. We report on the channel capacity of the MDR system and the optimal height of its mirrors in terms of maximum channel capacity. We also derived analytic results on the effect of rotation on MDR\\'s performance. Based on numerical and experimental results, we show that the double-sided mirror has both constructive and destructive effects on the channel matrix. Our design can be used with previously described non-imaging systems to improve the performance of indoor VLC systems.

Preliminary conceptual design of the blanket and power conversion system for the Mirror Hybrid Reactor

International Nuclear Information System (INIS)

Schultz, K.R.; Culver, D.W.; Rao, S.B.; Rao, S.R.

1978-01-01

A conceptual design of a commercial Mirror Hybrid Reactor, optimized for 239 Pu production, has been completed. This design is the product of a joint effort by Lawrence Livermore Laboratory and General Atomic Company, and follows directly from earlier work on the Mirror Hybrid. This paper describes the blanket and power conversion system of the reactor design. Included are descriptions of the prestressed concrete reactor vessel that supports the magnets and contains the blanket and power conversion system components, the blanket module design, the blanket fuel design, and the power conversion system

Mirror neurons and language in schizophrenia

OpenAIRE

Bendová, Marie

2016-01-01

Mirror neurons are a specific kind of visuomotor neurons that are involved in action execution and also in action perception. The mirror mechanism is linked to a variety of complex psychological functions such as social-cognitive functions and language. People with schizophrenia have often difficulties both in mirror neuron system and in language skills. In the first part of our research we studied the connectivity of mirror neuron areas (such as IFG, STG, PMC, SMC and so on) by fMRI in resti...

Development of the measurement system with interferometers for ultraprecise X-ray mirror

CERN Document Server

Yamauchi, K; Mimura, H

2003-01-01

A figure measurement system with a stitching method has been developed for evaluation and fabrication of the ultraprecise hard X-ray mirror optics. This system was constructed by two interferometers. One is the Michelson-type microscopic interferometer which is improved to keep the focus distance within 0.1 mu m. Another is the Fizeau's interferometer employed to compensate stitching error in the long spatial wavelength range. To estimate the absolute accuracy in this figure measurement system, the reflection X-ray intensity distributions of flat and aspherical mirrors, which are fabricated by us, were predicted by wave-optical simulation based on measured profile an compared with actually observed distributions. As the result, they are in good agreements. These agreements prove that the developed system has sub-nanometer absolute accuracy in all the spatial wavelength range longer than 0.5mm, because sub-nanometer figure error in those spatial wavelength ranges are known to affect reflection X-ray intensity ...

A mobile system for a comprehensive online-characterization of nanoparticle aggregates based on wide-angle light scattering and laser-induced incandescence

Energy Technology Data Exchange (ETDEWEB)

Huber, Franz J. T.; Will, Stefan, E-mail: stefan.will@fau.de [Lehrstuhl für Technische Thermodynamik (LTT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91058 (Germany); Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91052 (Germany); Cluster of Excellence Engineering of Advanced Materials (EAM), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91052 (Germany); Altenhoff, Michael [Lehrstuhl für Technische Thermodynamik (LTT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91058 (Germany); Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91052 (Germany)

2016-05-15

A mobile demonstrator for the comprehensive online-characterization of gas-borne nanoparticle aggregates is presented. Two optical measurement techniques are combined, both utilizing a pulsed Nd:YAG laser as light source. Aggregate size and fractal dimension are measured by Wide-Angle Light Scattering (WALS). An ellipsoidal mirror images elastically scattered light from scattering angles between 10° and 165° onto a CCD-camera chip resulting in an almost complete scattering diagram with high angular resolution. Primary particle size and volume fraction are measured by time-resolved Laser-Induced Incandescence (TiRe-LII). Here, particles are heated up to about 3000 K by the short laser pulse, the enhanced thermal radiation signal is detected with gated photomultiplier tubes. Analysis of the signal decay time and maximum LII-signal allows for the determination of primary particle diameter and volume fraction. The performance of the system is demonstrated by combined measurements on soot nanoparticle aggregates from a soot aerosol generator. Particle and aggregate sizes are varied by using different equivalence ratios of the combustion in the generator. Soot volume fraction can be adjusted by different levels of dilution with air. Online-measurements were carried out demonstrating the favorable performance of the system and the potential for industrial applications such as process control and product development. The particle properties obtained are confirmed through transmission electron microscopy analysis on representative samples.

A mobile system for a comprehensive online-characterization of nanoparticle aggregates based on wide-angle light scattering and laser-induced incandescence

International Nuclear Information System (INIS)

Huber, Franz J. T.; Will, Stefan; Altenhoff, Michael

2016-01-01

A mobile demonstrator for the comprehensive online-characterization of gas-borne nanoparticle aggregates is presented. Two optical measurement techniques are combined, both utilizing a pulsed Nd:YAG laser as light source. Aggregate size and fractal dimension are measured by Wide-Angle Light Scattering (WALS). An ellipsoidal mirror images elastically scattered light from scattering angles between 10° and 165° onto a CCD-camera chip resulting in an almost complete scattering diagram with high angular resolution. Primary particle size and volume fraction are measured by time-resolved Laser-Induced Incandescence (TiRe-LII). Here, particles are heated up to about 3000 K by the short laser pulse, the enhanced thermal radiation signal is detected with gated photomultiplier tubes. Analysis of the signal decay time and maximum LII-signal allows for the determination of primary particle diameter and volume fraction. The performance of the system is demonstrated by combined measurements on soot nanoparticle aggregates from a soot aerosol generator. Particle and aggregate sizes are varied by using different equivalence ratios of the combustion in the generator. Soot volume fraction can be adjusted by different levels of dilution with air. Online-measurements were carried out demonstrating the favorable performance of the system and the potential for industrial applications such as process control and product development. The particle properties obtained are confirmed through transmission electron microscopy analysis on representative samples.

Mirror reactor surface study

Energy Technology Data Exchange (ETDEWEB)

Hunt, A. L.; Damm, C. C.; Futch, A. H.; Hiskes, J. R.; Meisenheimer, R. G.; Moir, R. W.; Simonen, T. C.; Stallard, B. W.; Taylor, C. E.

1976-09-01

A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included.

Mirror reactor surface study

International Nuclear Information System (INIS)

Hunt, A.L.; Damm, C.C.; Futch, A.H.; Hiskes, J.R.; Meisenheimer, R.G.; Moir, R.W.; Simonen, T.C.; Stallard, B.W.; Taylor, C.E.

1976-01-01

A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included

System and method for online inspection of turbines using an optical tube with broadspectrum mirrors

Science.gov (United States)

Baleine, Erwan

2015-12-22

An optical inspection system for nondestructive internal visual inspection and non-contact infra-red (IR) temperature monitoring of an online, operating power generation turbine. The optical inspection system includes an optical tube having a viewing port, at least one reflective mirror or a mirror array having a reflectivity spectral range from 550 nm to 20 .mu.m, and capable of continuous operation at temperatures greater than 932 degrees Fahrenheit (500 degrees Celsius), and a transparent window with high transmission within the same spectral range mounted distal the viewing port. The same optical mirror array may be used to measure selectively surface temperature of metal turbine blades in the near IR range (approximately 1 .mu.m wavelength) and of thermal barrier coated turbine blades in the long IR range (approximately 10 .mu.m wavelength).

EEG study of the mirror neuron system in children with high functioning autism.

Science.gov (United States)

Raymaekers, Ruth; Wiersema, Jan Roelf; Roeyers, Herbert

2009-12-22

Individuals with Autism Spectrum Disorder (ASD) are characterised by an impaired imitation, thought to be critical for early affective, social and communicative development. One neurological system proposed to underlie this function is the mirror neuron system (MNS) and previous research has suggested a dysfunctional MNS in ASD. The EEG mu frequency, more precisely the reduction of the mu power, is considered to be an index for mirror neuron functioning. In this work, EEG registrations are used to evaluate the mirror neuron functioning of twenty children with high functioning autism (HFA) between 8 and 13 years. Their mu suppression to self-executed and observed movement is compared to typically developing peers and related to age, intelligence and symptom severity. Both groups show significant mu suppression to both self and observed hand movements. No group differences are found in either condition. These results do not support the hypothesis that HFA is associated with a dysfunctional MNS. The discrepancy with previous research is discussed in light of the heterogeneity of the ASD population.

High beta capture and mirror confinement of laser produced plasmas. Semiannual report, July 1, 1975--January 31, 1976

International Nuclear Information System (INIS)

Haught, A.F.; Polk, D.H.; Fader, W.J.; Tomlinson, R.G.; Jong, R.A.; Ard, W.B.; Mensing, A.E.; Churchill, T.L.; Stufflebeam, J.H.; Bresnock, F.J.

1976-01-01

The Laser Initiated Target Experiment (LITE) at the United Technologies Research Center is designed to address the target plasma buildup approach to a steady state mirror fusion device. A dense, mirror confined, target plasma is produced by high power laser irradiation of a solid lithium hydride particle, electrically suspended in a vacuum at the center of an established minimum-B magnetic field. Following expansion in and capture by the magnetic field, this target plasma is irradiated by an energetic neutral hydrogen beam. Charge exchange collisions with energetic beam particles serve to heat the confined plasma while ionization of the neutral beam atoms and trapping in the mirror magnetic field add particles to the confined plasma. For sufficiently high beam intensities, confined plasmas losses will be offset so that buildup of the plasma density occurs, thus demonstrating sustenance and fueling as well as the heating by neutral beam injection of a steady state mirror fusion device. Investigations of the decay of the magnetically confined target plasmas and initial studies of energetic neutral beam injection into confined target plasmas, conducted during this report period, are presented. Additional development of the LITE experimental systems including improvements in the laser plasma production facility, the energetic neutral beam line, and the heavy ion probe diagnostic is reported. A series of calculations on enhanced scattering and classical decay for plasma mirror confined in a LITE type system are discussed

Microscopic cluster model analysis of 14O+p elastic scattering

International Nuclear Information System (INIS)

Baye, D.; Descouvemont, P.; Leo, F.

2005-01-01

The 14 O+p elastic scattering is discussed in detail in a fully microscopic cluster model. The 14 O cluster is described by a closed p shell for protons and a closed p3/2 subshell for neutrons in the translation-invariant harmonic-oscillator model. The exchange and spin-orbit parameters of the effective forces are tuned on the energy levels of the 15 C mirror system. With the generator-coordinate and microscopic R-matrix methods, phase shifts and cross sections are calculated for the 14 O+p elastic scattering. An excellent agreement is found with recent experimental data. A comparison is performed with phenomenological R-matrix fits. Resonances properties in 15 F are discussed

Mirror power reactor magnet coil system: a technically and economically feasible design

International Nuclear Information System (INIS)

Peterson, M.A.

1977-01-01

The design and preliminary engineering analysis of a ''Yin Yang'' coil system utilizing several original design concepts to achieve technical and economic feasibility will be presented. The design analysis is begun with a general description of the constraints and prerequisites which define the problem of designing a satisfactory coil system for a mirror power reactor. This description includes a discussion of the coil conductor geometry required by plasma physics considerations, and also a description of the magnitude and direction of the magnetic force system distributed over the conductor geometry. In addition, the important design constraints which all mirror coil system designs must satisfy if they are to successfully interface with the other reactor components are reviewed. After considering the basic constraints that Yin Yong coil systems must be developed around, a survey of the various design concepts that were developed and explored in search of a satisfactory coil system design is discussed. From this extensive preliminary investigation of potential coil system configurations, a coil system design was developed which appears to offer by far the best combination of technical and economic feasibility of any other coil system design developed thus far

Gasdynamic Mirror Fusion Propulsion Experiment

Science.gov (United States)

Emrich, Bill; Rodgers, Stephen L. (Technical Monitor)

2000-01-01

A gasdynamic mirror (GDM) fusion propulsion experiment is currently being constructed at the NASA Marshall Space Flight Center (MSFC) to test the feasibility of this particular type of fusion device. Because of the open magnetic field line configuration of mirror fusion devices, they are particularly well suited for propulsion system applications since they allow for the easy ejection of thrust producing plasma. Currently, the MSFC GDM is constructed in three segments. The vacuum chamber mirror segment, the plasma injector mirror segment, and the main plasma chamber segment. Enough magnets are currently available to construct up to three main plasma chamber segments. The mirror segments are also segmented such that they can be expanded to accommodate new end plugging strategies with out requiring the disassembly of the entire mirror segment. The plasma for the experiment is generated in a microwave cavity located between the main magnets and the mirror magnets. Ion heating is accomplished through ambipolar diffusion. The objective of the experiment is to investigate the stability characteristics of the gasdynamic mirror and to map a region of parameter space within which the plasma can be confined in a stable steady state configuration. The mirror ratio, plasma density, and plasma "b" will be varied over a range of values and measurements subsequently taken to determine the degree of plasma stability.

Centrifugal particle confinement in mirror geometry

Science.gov (United States)

White, Roscoe; Hassam, Adil; Brizard, Alain

2018-01-01

The use of supersonic rotation of a plasma in mirror geometry has distinct advantages for thermonuclear fusion. The device is steady state, there are no disruptions, the loss cone is almost closed, sheared rotation stabilizes magnetohydrodynamic instabilities as well as plasma turbulence, there are no runaway electrons, and the coil configuration is simple. In this work, we examine the effect of rotation on mirror confinement using a full cyclotron orbit code. The full cyclotron simulations give a much more complete description of the particle energy distribution and losses than the use of guiding center equations. Both collisionless loss as a function of rotation and the effect of collisions are investigated. Although the cross field diffusion is classical, we find that the local rotating Maxwellian is increased to higher energy, increasing the fusion rate and also enhancing the radial diffusion. We find a loss channel not envisioned with a guiding center treatment, but a design can be chosen that can satisfy the Lawson criterion for ions. Of course, the rotation has a minimal effect on the alpha particle birth distribution, so there is initially loss through the usual loss cone, just as in a mirror with no rotation. However after this loss, the alphas slow down on the electrons with little pitch angle scattering until reaching low energy, so over half of the initial alpha energy is transferred to the electrons. The important problem of energy confinement, with losses primarily through the electron channel, is not addressed in this work. We also discuss the use of rotating mirror geometry to produce an ion thruster.

Magnetic mirror fusion: status and prospects

International Nuclear Information System (INIS)

Post, R.F.

1980-01-01

Two improved mirror systems, the tandem mirror (TM) and the field-reversed mirror (FRM) are being intensively studied. The twin practical aims of these studies: to improve the economic prospects for mirror fusion power plants and to reduce the size and/or complexity of such plants relative to earlier approaches to magnetic fusion. While at the present time the program emphasis is still strongly oriented toward answering scientific questions, the emphasis is shifting as the data accumulates and as larger facilities - ones with a heavy technological and engineering orientation - are being prepared. The experimental and theoretical progress that led to the new look in mirror fusion research is briefly reviewed, the new TM and the FRM ideas are outlined, and the projected future course of mirror fusion research is discussed

Real-time high-speed motion blur compensation system based on back-and-forth motion control of galvanometer mirror.

Science.gov (United States)

Hayakawa, Tomohiko; Watanabe, Takanoshin; Ishikawa, Masatoshi

2015-12-14

We developed a novel real-time motion blur compensation system for the blur caused by high-speed one-dimensional motion between a camera and a target. The system consists of a galvanometer mirror and a high-speed color camera, without the need for any additional sensors. We controlled the galvanometer mirror with continuous back-and-forth oscillating motion synchronized to a high-speed camera. The angular speed of the mirror is given in real time within 10 ms based on the concept of background tracking and rapid raw Bayer block matching. Experiments demonstrated that our system captures motion-invariant images of objects moving at speeds up to 30 km/h.

EUV multilayer mirror, optical system including a multilayer mirror and method of manufacturing a multilayer mirror

NARCIS (Netherlands)

Huang, Qiushi; Louis, Eric; Bijkerk, Frederik; de Boer, Meint J.; von Blanckenhagen, G.

2016-01-01

A multilayer mirror (M) reflecting extreme ultraviolet (EUV) radiation from a first wave-length range in a EUV spectral region comprises a substrate (SUB) and a stack of layers (SL) on the substrate, the stack of layers comprising layers comprising a low index material and a high index material, the

Report of the workshop on rf heating in mirror systems

International Nuclear Information System (INIS)

Price, R.E.; Woo, J.T.

1980-08-01

This report is prepared from the proceedings of the Workshop on RF Heating in Magnetic Mirror Systems held at DOE Headquarters in Washington, DC, on March 10-12, 1980. The workshop was organized into four consecutive half-day sessions of prepared talks and one half-day discussion. The first session on tandem mirror concepts and program plans served to identify the opportunities for the application of rf power and the specific approaches that are being pursued. A summary of the ideas presented in this session is given. The following sessions of the workshop were devoted to an exposition of current theoretical and experimental knowledge on the interaction of rf power with magnetically confined, dense, high temperature plasmas at frequencies near the electron cyclotron resonance, lower hybrid resonance and ion cyclotron resonance (including magnetosonic) ranges. The conclusions from these proceedings are presented

Demonstration of Focusing Wolter Mirrors for Neutron Phase and Magnetic Imaging

Directory of Open Access Journals (Sweden)

Daniel S. Hussey

2018-03-01

Full Text Available Image-forming focusing mirrors were employed to demonstrate their applicability to two different modalities of neutron imaging, phase imaging with a far-field interferometer, and magnetic-field imaging through the manipulation of the neutron beam polarization. For the magnetic imaging, the rotation of the neutron polarization in the magnetic field was measured by placing a solenoid at the focus of the mirrors. The beam was polarized upstream of the solenoid, while the spin analyzer was situated between the solenoid and the mirrors. Such a polarized neutron microscope provides a path toward considerably improved spatial resolution in neutron imaging of magnetic materials. For the phase imaging, we show that the focusing mirrors preserve the beam coherence and the path-length differences that give rise to the far-field moiré pattern. We demonstrated that the visibility of the moiré pattern is modified by small angle scattering from a highly porous foam. This experiment demonstrates the feasibility of using Wolter optics to significantly improve the spatial resolution of the far-field interferometer.

Reduced mu suppression and altered motor resonance in euthymic bipolar disorder: Evidence for a dysfunctional mirror system?

Science.gov (United States)

Andrews, Sophie C; Enticott, Peter G; Hoy, Kate E; Thomson, Richard H; Fitzgerald, Paul B

2016-01-01

Social cognitive difficulties are common in the acute phase of bipolar disorder and, to a lesser extent, during the euthymic stage, and imaging studies of social cognition in euthymic bipolar disorder have implicated mirror system brain regions. This study aimed to use a novel multimodal approach (i.e., including both transcranial magnetic stimulation (TMS) and electroencephalogram (EEG)) to investigate mirror systems in bipolar disorder. Fifteen individuals with euthymic bipolar disorder and 16 healthy controls participated in this study. Single-pulse TMS was applied to the optimal site in the primary motor cortex (M1), which stimulates the muscle of interest during the observation of hand movements (goal-directed or interacting) designed to elicit mirror system activity. Single EEG electrodes (C3, CZ, C4) recorded mu rhythm modulation concurrently. Results revealed that the patient group showed significantly less mu suppression compared to healthy controls. Surprisingly, motor resonance was not significantly different overall between groups; however, bipolar disorder participants showed a pattern of reduced reactivity on some conditions. Although preliminary, this study indicates a potential mirror system deficit in euthymic bipolar disorder, which may contribute to the pathophysiology of the disorder.

Mechanical-engineering aspects of mirror-fusion technology

International Nuclear Information System (INIS)

Fisher, D.K.; Doggett, J.N.

1982-01-01

The mirror approach to magnetic fusion has evolved from the original simple mirror cell to today's mainline effort: the tandem-mirror machine with thermal barriers. Physics and engineering research is being conducted throughout the world, with major efforts in Japan, the USSR, and the US. At least one facility under construction (MFTF-B) will approach equivalent energy breakeven in physics performance. Significant mechanical engineering development is needed, however, before a demonstration reactor can be constructed. The principal areas crucial to mirror reactor development include large high-field superconducting magnets, high-speed continuous vacuum-pumping systems, long-pulse high-power neutral-beam and rf-plasma heating systems, and efficient high-voltage high-power direct converters. Other areas common to all fusion systems include tritium handling technology, first-wall materials development, and fusion blanket design

Neural mirroring and social interaction: Motor system involvement during action observation relates to early peer cooperation.

Science.gov (United States)

Endedijk, H M; Meyer, M; Bekkering, H; Cillessen, A H N; Hunnius, S

2017-04-01

Whether we hand over objects to someone, play a team sport, or make music together, social interaction often involves interpersonal action coordination, both during instances of cooperation and entrainment. Neural mirroring is thought to play a crucial role in processing other's actions and is therefore considered important for social interaction. Still, to date, it is unknown whether interindividual differences in neural mirroring play a role in interpersonal coordination during different instances of social interaction. A relation between neural mirroring and interpersonal coordination has particularly relevant implications for early childhood, since successful early interaction with peers is predictive of a more favorable social development. We examined the relation between neural mirroring and children's interpersonal coordination during peer interaction using EEG and longitudinal behavioral data. Results showed that 4-year-old children with higher levels of motor system involvement during action observation (as indicated by lower beta-power) were more successful in early peer cooperation. This is the first evidence for a relation between motor system involvement during action observation and interpersonal coordination during other instances of social interaction. The findings suggest that interindividual differences in neural mirroring are related to interpersonal coordination and thus successful social interaction. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Diffraction scattering of strongly bound system

International Nuclear Information System (INIS)

Kuzmichev, V.E.

1982-04-01

The scattering of a hadron on a strongly bound system of two hadrons (dihadron) is considered in the high-energy limit for the relative hadron-dihadron motion. The dihadron scatterer motion and the internal interaction are included in our consideration. It is shown that only small values of the internal transfer momentum of dihadron particles bring the principal contribution to the three-particle propagator in eikonal approximation. On the basis of the exact analytical solution of the integral equation for the total Green function the scattering amplitude is derived. It is shown that the scattering amplitude contains only single, double, and triple scattering terms. The three new terms to the Glauber formula for the total cross section are obtained. These terms decrease both the true total hadron-hadron cross section and the screening correction. (orig.)

Parametric systems analysis for tandem mirror hybrids

International Nuclear Information System (INIS)

Lee, J.D.; Chapin, D.L.; Chi, J.W.H.

1980-09-01

Fusion fission systems, consisting of fissile producing fusion hybrids combining a tandem mirror fusion driver with various blanket types and net fissile consuming LWR's, have been modeled and analyzed parametrically. Analysis to date indicates that hybrids can be competitive with mined uranium when U 3 O 8 cost is about 100 $/lb., adding less than 25% to present day cost of power from LWR's. Of the three blanket types considered, uranium fast fission (UFF), thorium fast fission (ThFF), and thorium fission supressed (ThFS), the ThFS blanket has a modest economic advantage under most conditions but has higher support ratios and potential safety advantages under all conditions

Mirror fusion reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Moir, R.W.

1978-01-01

We have carried out conceptual design studies of fusion reactors based on the three current mirror confinement concepts: the standard mirror, the tandem mirror, and the field-reversed mirror. Recent studies of the standard mirror have emphasized its potential as a fusion-fission hybrid reactor, designed to produce fission fuel for fission reactors. We have designed a large commercial hybrid based on standard mirror confinement, and also a small pilot plant hybrid. Tandem mirror designs include a commercial 1000 MWe fusion power plant and a nearer term tandem mirror hybrid. Field-reversed mirror designs include a multicell commercial reactor producing 75 MWe and a single cell pilot plant

Mirror fusion reactors

International Nuclear Information System (INIS)

Anon.

1978-01-01

Conceptual design studies were made of fusion reactors based on the three current mirror-confinement concepts: the standard mirror, the tandem mirror, and the field-reversed mirror. Recent studies of the standard mirror have emphasized its potential as a fusion-fission hybrid reactor, designed to produce fuel for fission reactors. We have designed a large commercial hybrid and a small pilot-plant hybrid based on standard mirror confinement. Tandem mirror designs include a commercial 1000-MWe fusion power plant and a nearer term tandem mirror hybrid. Field-reversed mirror designs include a multicell commercial reactor producing 75 MWe and a single-cell pilot plant

Scattering theory for open quantum systems

International Nuclear Information System (INIS)

Behrndt, Jussi

2006-01-01

Quantum systems which interact with their environment are often modeled by maximal dissipative operators or so-called Pseudo-Hamiltonians. In this paper the scattering theory for such open systems is considered. First it is assumed that a single maximal dissipative operator A D in a Hilbert space H is used to describe an open quantum system. In this case the minimal self-adjoint dilation K of A D can be regarded as the Hamiltonian of a closed system which contains the open system {A D ,h}, but since K is necessarily not semibounded from below, this model is difficult to interpret from a physical point of view. In the second part of the paper an open quantum system is modeled with a family {A(μ)} of maximal dissipative operators depending on energy μ, and it is shown that the open system can be embedded into a closed system where the Hamiltonian is semibounded. Surprisingly it turns out that the corresponding scattering matrix can be completely recovered from scattering matrices of single Pseudo-Hamiltonians as in the first part of the paper. The general results are applied to a class of Sturm-Liouville operators arising in dissipative and quantum transmitting Schroedinger-Poisson systems. (orig.)

Scattering theory for open quantum systems

Energy Technology Data Exchange (ETDEWEB)

Behrndt, Jussi [Technische Univ. Berlin (Germany). Inst. fuer Mathematik; Malamud, Mark M. [Donetsk National University (Ukraine). Dept. of Mathematics; Neidhardt, Hagen [Weierstrass-Institut fuer Angewandte Analysis und Stochastik (WIAS) im Forschungsverbund Berlin e.V. (Germany)

2006-07-01

Quantum systems which interact with their environment are often modeled by maximal dissipative operators or so-called Pseudo-Hamiltonians. In this paper the scattering theory for such open systems is considered. First it is assumed that a single maximal dissipative operator A{sub D} in a Hilbert space H is used to describe an open quantum system. In this case the minimal self-adjoint dilation K of A{sub D} can be regarded as the Hamiltonian of a closed system which contains the open system {l_brace}A{sub D},h{r_brace}, but since K is necessarily not semibounded from below, this model is difficult to interpret from a physical point of view. In the second part of the paper an open quantum system is modeled with a family {l_brace}A({mu}){r_brace} of maximal dissipative operators depending on energy {mu}, and it is shown that the open system can be embedded into a closed system where the Hamiltonian is semibounded. Surprisingly it turns out that the corresponding scattering matrix can be completely recovered from scattering matrices of single Pseudo-Hamiltonians as in the first part of the paper. The general results are applied to a class of Sturm-Liouville operators arising in dissipative and quantum transmitting Schroedinger-Poisson systems. (orig.)

Granularity of the mirror neuron system: A complex endeavor. Comment on "Grasping synergies: A motor-control approach to the mirror neuron mechanism" by A. D'Ausilio et al.

Science.gov (United States)

Swinnen, S. P.; Alaerts, K.

2015-03-01

The review paper by D'Ausilio and coauthors [3] is very timely and addresses one of the long-standing issues with respect to the coding features of mirror neurons. Through the history of mirror neuron research, there has been some controversy with respect to the level of granularity of the mirror neuron system, as studied in animal and human systems. While some researchers have suggested that abstract (high level) features of movement are coded, others have claimed evidence for more muscle specific (low level) coding properties (for an example, see [1,2]). D'Ausilio et al. [3] take a strong position in their review, suggesting a convergence between basic mechanisms of movement control and the mirror neuron system. Their suggestion is inspired by Bernstein's influential work on the so-called degrees of freedom problem. Even though a goal can in principle be reached in an infinite number of ways, consistent and stereotypical patterns of kinematics and muscle activation are often observed [4]. This has led to the notion of movement synergies as the basic building blocks for movement control. Even though it is essentially possible to contract isolated muscles or even motor units, Bernstein suggested that control of complex movement relies on movement synergies or coordinative structures, referring to a group of muscles that behave as a functional unit. This reduces the computational demands of the central nervous system considerably by assigning more responsibility to the lower levels of the movement control system. Bernstein's approach has inspired the dynamical systems perspective that has focused on a better understanding of complex biological systems such as interlimb coordination in humans [8]. For example, the upper limbs behave as a coordinative structure whereby simultaneous activation of the homologous muscle groups constitutes the default or preferred coordination mode that has to be defied when alternative patterns of coordination need to be performed or

Sensorimotor learning and the ontogeny of the mirror neuron system

OpenAIRE

Catmur, C

2013-01-01

Mirror neurons, which have now been found in the human and songbird as well as the macaque, respond to both the observation and the performance of the same action. It has been suggested that their matching response properties have evolved as an adaptation for action understanding; alternatively, these properties may arise through sensorimotor experience. Here I review mirror neuron response characteristics from the perspective of ontogeny; I discuss the limited evidence for mirror neurons in ...

Chiral mirrors

International Nuclear Information System (INIS)

Plum, Eric; Zheludev, Nikolay I.

2015-01-01

Mirrors are used in telescopes, microscopes, photo cameras, lasers, satellite dishes, and everywhere else, where redirection of electromagnetic radiation is required making them arguably the most important optical component. While conventional isotropic mirrors will reflect linear polarizations without change, the handedness of circularly polarized waves is reversed upon reflection. Here, we demonstrate a type of mirror reflecting one circular polarization without changing its handedness, while absorbing the other. The polarization-preserving mirror consists of a planar metasurface with a subwavelength pattern that cannot be superimposed with its mirror image without being lifted out of its plane, and a conventional mirror spaced by a fraction of the wavelength from the metasurface. Such mirrors enable circularly polarized lasers and Fabry-Pérot cavities with enhanced tunability, gyroscopic applications, polarization-sensitive detectors of electromagnetic waves, and can be used to enhance spectroscopies of chiral media

Mirror agnosia and the mirrored-self misidentification delusion: a hypnotic analogue.

Science.gov (United States)

Connors, Michael H; Cox, Rochelle E; Barnier, Amanda J; Langdon, Robyn; Coltheart, Max

2012-05-01

Mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. Current theories suggest that one pathway to the delusion is mirror agnosia (a deficit in which patients are unable to use mirror knowledge when interacting with mirrors). This study examined whether a hypnotic suggestion for mirror agnosia can recreate features of the delusion. Ten high hypnotisable participants were given either a suggestion to not understand mirrors or to see the mirror as a window. Participants were asked to look into a mirror and describe what they saw. Participants were tested on their understanding of mirrors and received a series of challenges. Participants then received a detailed postexperimental inquiry. Three of five participants given the suggestion to not understand mirrors reported seeing a stranger and maintained this belief when challenged. These participants also showed signs of mirror agnosia. No participants given the suggestion to see a window reported seeing a stranger. Results indicate that a hypnotic suggestion for mirror agnosia can be used to recreate the mirrored-self misidentification delusion. Factors influencing the effectiveness of hypnotic analogues of psychopathology, such as participants' expectations and interpretations, are discussed.

Entangling movable mirrors in a double cavity system

DEFF Research Database (Denmark)

Pinard, Michel; Dantan, Aurelien Romain; Vitali, David

2005-01-01

We propose a double-cavity set-up capable of generating a stationary entangled state of two movable mirrors at cryogenic temperatures. The scheme is based on the optimal transfer of squeezing of input optical fields to mechanical vibrational modes of the mirrors, realized by the radiation pressure...... of the intracavity light. We show that the presence of macroscopic entanglement can be demonstrated by an appropriate readout of the output light of the two cavities....

Plasma impact on diagnostic mirrors in JET

OpenAIRE

A. Garcia-Carrasco; P. Petersson; M. Rubel; A. Widdowson; E. Fortuna-Zalesna; S. Jachmich; M. Brix; L. Marot

2017-01-01

Metallic mirrors will be essential components of all optical systems for plasma diagnosis in ITER. This contribution provides a comprehensive account on plasma impact on diagnostic mirrors in JET with the ITER-Like Wall. Specimens from the First Mirror Test and the lithium-beam diagnostic have been studied by spectrophotometry, ion beam analysis and electron microscopy. Test mirrors made of molybdenum were retrieved from the main chamber and the divertor after exposure to the 2013–2014 experi...

Scattering cross section for various potential systems

Directory of Open Access Journals (Sweden)

Myagmarjav Odsuren

2017-08-01

Full Text Available We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.

Scattering cross section for various potential systems

Energy Technology Data Exchange (ETDEWEB)

Odsuren, Myagmarjav; Khuukhenkhuu, Gonchigdorj; Davaa, Suren [Nuclear Research Center, School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar (Mongolia); Kato, Kiyoshi [Nuclear Reaction Data Centre, Faculty of Science, Hokkaido University, Sapporo (Japan)

2017-08-15

We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.

Mirror profile optimization for nano-focusing KB mirror

International Nuclear Information System (INIS)

Zhang Lin; Baker, Robert; Barrett, Ray; Cloetens, Peter; Dabin, Yves

2010-01-01

A KB focusing mirror width profile has been optimized to achieve nano-focusing for the nano-imaging end-station ID22NI at the ESRF. The complete mirror and flexure bender assembly has been modeled in 3D with finite element analysis using ANSYS. Bender stiffness, anticlastic effects and geometrical non-linear effects have been considered. Various points have been studied: anisotropy and crystal orientation, stress in the mirror and bender, actuator resolution and the mirror-bender adhesive bonding... Extremely high performance of the mirror is expected with residual slope error smaller than 0.6 μrad, peak-to-valley, compared to the bent slope of 3000 μrad.

Mirror suspension system for the TAMA SAS

CERN Document Server

Takamori, A; Bertolini, A; Cella, G; DeSalvo, R; Fukushima, M; Iida, Y; Jacquier, F; Kawamura, S; Marka, S; Nishi, Y; Numata, K; Sannibale, V; Somiya, K; Takahashi, R; Tariq, H; Tsubono, K; Ugas, J; Viboud, N; Yamamoto, H; Yoda, T; Wang Chen Yang

2002-01-01

Several R and D programmes are ongoing to develop the next generation of interferometric gravitational wave detectors providing the superior sensitivity desired for refined astronomical observations. In order to obtain a wide observation band at low frequencies, the optics need to be isolated from the seismic noise. The TAMA SAS (seismic attenuation system) has been developed within an international collaboration between TAMA, LIGO, and some European institutes, with the main objective of achieving sufficient low-frequency seismic attenuation (-180 dB at 10 HZ). The system suppresses seismic noise well below the other noise levels starting at very low frequencies above 10 Hz. It also includes an active inertial damping system to decrease the residual motion of the optics enough to allow a stable operation of the interferometer. The TAMA SAS also comprises a sophisticated mirror suspension subsystem (SUS). The SUS provides support for the optics and vibration isolation complementing the SAS performance. The SU...

Mirror reactor studies

International Nuclear Information System (INIS)

Moir, R.W.; Barr, W.L.; Bender, D.J.

1977-01-01

Design studies of a fusion mirror reactor, a fusion-fission mirror reactor, and two small mirror reactors are summarized. The fusion reactor uses 150-keV neutral-beam injectors based on the acceleration of negative ions. The injectors provide over 1 GW of continuous power at an efficiency greater than 80%. The fusion reactor has three-stage, modularized, Venetian blind, plasma direct converter with a predicted efficiency of 59% and a new concept for removal of the lune-shaped blanket: a crane is brought between the two halves of the Yin-Yang magnet, which are separated by a float. The design has desirable features such as steady-state operation, minimal impurity problems, and low first-wall thermal stress. The major disadvantage is low Q resulting in high re-circulating power and hence high cost of electrical power. However, the direct capital cost per unit of gross electrical power is reasonable [$1000/kW(e)]. By contrast, the fusion-fission reactor design is not penalized by re-circulating power and uses relatively near-term fusion technology being developed for the fusion power program. New results are presented on the Th- 233 U and the U- 239 Pu fuel cycles. The purpose of this hybrid is fuel production, with projected costs at $55/g of Pu or $127/g of 233 U. Blanket and cooling system designs, including an emergency cooling system, by General Atomic Company, lead us to the opinion that the reactor can meet expected safety standards for licensing. The smallest mirror reactor having only a shield between the plasma and the coil is the 4.2-m long fusion engineering research facility (FERF) designed for material irradiation. The smallest mirror reactor having both a blanket and shield is the 7.5-m long experimental power reactor (EPR), which has both a fusion and a fusion-fission version. (author)

Thermal forming of glass microsheets for x-ray telescope mirror segments

DEFF Research Database (Denmark)

Jimenez-Garate, M.A.; Hailey, C.J.; Craig, W.W.

2003-01-01

envisioned for future x-ray observatories. The glass microsheets are shaped into mirror segments at high temperature by use of a guiding mandrel, without polishing. We determine the physical properties and mechanisms that elucidate the formation process and that are crucial to improve surface quality. We......We describe a technology to mass-produce ultrathin mirror substrates for x-ray telescopes of near Wolter-I geometry. Thermal glass forming is a low-cost method to produce high-throughput, spaceborne x-ray mirrors for the 0.1-200-keV energy band. These substrates can provide the collecting area...... develop a viscodynamic model for the glass strain as the forming proceeds to find the conditions for repeatability. Thermal forming preserves the x-ray reflectance and scattering properties of the raw glass. The imaging resolution is driven by a large wavelength figure. We discuss the sources of figure...

An augmented reality home-training system based on the mirror training and imagery approach.

Science.gov (United States)

Trojan, Jörg; Diers, Martin; Fuchs, Xaver; Bach, Felix; Bekrater-Bodmann, Robin; Foell, Jens; Kamping, Sandra; Rance, Mariela; Maaß, Heiko; Flor, Herta

2014-09-01

Mirror training and movement imagery have been demonstrated to be effective in treating several clinical conditions, such as phantom limb pain, stroke-induced hemiparesis, and complex regional pain syndrome. This article presents an augmented reality home-training system based on the mirror and imagery treatment approaches for hand training. A head-mounted display equipped with cameras captures one hand held in front of the body, mirrors this hand, and displays it in real time in a set of four different training tasks: (1) flexing fingers in a predefined sequence, (2) moving the hand into a posture fitting into a silhouette template, (3) driving a "Snake" video game with the index finger, and (4) grasping and moving a virtual ball. The system records task performance and transfers these data to a central server via the Internet, allowing monitoring of training progress. We evaluated the system by having 7 healthy participants train with it over the course of ten sessions of 15-min duration. No technical problems emerged during this time. Performance indicators showed that the system achieves a good balance between relatively easy and more challenging tasks and that participants improved significantly over the training sessions. This suggests that the system is well suited to maintain motivation in patients, especially when it is used for a prolonged period of time.

Why is your spouse so predictable? Connecting mirror neuron system and self-expansion model of love.

Science.gov (United States)

Ortigue, Stephanie; Bianchi-Demicheli, Francesco

2008-12-01

The simulation theory assumes we understand actions and intentions of others through a direct matching process. This matching process activates a complex brain network involving the mirror neuron system (MNS), which is self-related and active when one does something or observes someone else acting. Because social psychology admits that mutual intention's understanding grows in close relationship as love grows, we hypothesize that mirror mechanisms take place in love relationships. The similarities between the mirror matching process and the mutual intention's understanding that occurs when two persons are in love suggest that exposure to love might affect functional and neural mechanisms, thus facilitating the understanding of the beloved's intentions. Congruent with our hypothesis, our preliminary results from 38 subjects strongly suggest a significant facilitation effect of love on understanding the intentions of the beloved (as opposed to control stimuli). Based on these phenomenological, and neurofunctional findings we suggest that the mirror mechanisms are involved in the facilitation effects of love for understanding intentions, and might further be extended to any types of love (e.g., passionate love, maternal love). Love experiences are important not only to the beloved himself, but also to any societal, cultural, and institutional patterns that relate to love. Yet, concerning its subjective character, love experiences are difficult to access. The modern procedures and techniques of socio-cognitive neuroscience make it possible to understand love and self-related experiences not only by the analysis of subjective self-reported questionnaires, but also by approaching the automatic (non-conscious) mirror experiences of love in healthy subjects, and neurological patients with a brain damage within the mirror neuron system. Although the psychology of love is now well admitted, the systematic study of the automatic facilitation effect of love through mirror

Relativistic electron mirrors from high intensity laser nanofoil interactions

International Nuclear Information System (INIS)

Kiefer, Daniel

2012-01-01

The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ 2 , where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those

FMRI evidence of 'mirror' responses to geometric shapes.

Science.gov (United States)

Press, Clare; Catmur, Caroline; Cook, Richard; Widmann, Hannah; Heyes, Cecilia; Bird, Geoffrey

2012-01-01

Mirror neurons may be a genetic adaptation for social interaction. Alternatively, the associative hypothesis proposes that the development of mirror neurons is driven by sensorimotor learning, and that, given suitable experience, mirror neurons will respond to any stimulus. This hypothesis was tested using fMRI adaptation to index populations of cells with mirror properties. After sensorimotor training, where geometric shapes were paired with hand actions, BOLD response was measured while human participants experienced runs of events in which shape observation alternated with action execution or observation. Adaptation from shapes to action execution, and critically, observation, occurred in ventral premotor cortex (PMv) and inferior parietal lobule (IPL). Adaptation from shapes to execution indicates that neuronal populations responding to the shapes had motor properties, while adaptation to observation demonstrates that these populations had mirror properties. These results indicate that sensorimotor training induced populations of cells with mirror properties in PMv and IPL to respond to the observation of arbitrary shapes. They suggest that the mirror system has not been shaped by evolution to respond in a mirror fashion to biological actions; instead, its development is mediated by stimulus-general processes of learning within a system adapted for visuomotor control.

FIR interferometer and scattering measurements of ATF

International Nuclear Information System (INIS)

Ma, C.H.; Hutchinson, D.P.; Fockedey, Y.; Vander Sluis, K.L.; Bennett, C.A.

1989-01-01

A 15-channel far-infrared (FIR) interferometer system has been constructed to measure the electron densities on the ATF plasmas. The system consists of a pair of cw 214-μm difluoromethane (CH 2 F 2 ) lasers, optically pumped by separate CO 2 lasers. The large number of channels is achieved by the use of reflective beam expansion optics to create a beam of 2 cm /times/ 45 cm. After passing through the plasma discharge, the elongated beam produced by the cylindrical mirrors is dissected by an array of 15 off-axis paraboloid reflectors, each of which illuminates a single Schottky-diode detector. The use of the beam expanding optics system reduces the number of optical elements required for the interferometer to approximately 2-3 per channel. The FIR laser beams are transported from the laser room to the experimental area by 25 mm i.d. dielectric waveguides purged with dry nitrogen. The system can also be operated at a wavelength of 119-μm by changing the gas in FIR laser cavities to methanol for high density experiments. Details of the system are described. A study is underway to determine the optimum design of a FIR scattering system for the ATF. This scattering system will be used to investigate density fluctuations with scale lengths from 0.1 cm to the plasma radius. The laser for this scattering system may be operated at wavelengths of 447, 307, 214, 184, and 119 μm with power levels of 100 to 500 mW. A summary of the study is presented. 6 refs., 1 fig

Laser cleaning of ITER's diagnostic mirrors

Science.gov (United States)

Skinner, C. H.; Gentile, C. A.; Doerner, R.

2012-10-01

Practical methods to clean ITER's diagnostic mirrors and restore reflectivity will be critical to ITER's plasma operations. We report on laser cleaning of single crystal molybdenum mirrors coated with either carbon or beryllium films 150 - 420 nm thick. A 1.06 μm Nd laser system provided 220 ns pulses at 8 kHz with typical power densities of 1-2 J/cm^2. The laser beam was fiber optically coupled to a scanner suitable for tokamak applications. The efficacy of mirror cleaning was assessed with a new technique that combines microscopic imaging and reflectivity measurements [1]. The method is suitable for hazardous materials such as beryllium as the mirrors remain sealed in a vacuum chamber. Excellent restoration of reflectivity for the carbon coated Mo mirrors was observed after laser scanning under vacuum conditions. For the beryllium coated mirrors restoration of reflectivity has so far been incomplete and modeling indicates that a shorter duration laser pulse is needed. No damage of the molybdenum mirror substrates was observed.[4pt][1] C.H. Skinner et al., Rev. Sci. Instrum. at press.

Symmetry relationships for multiple scattering of polarized light in turbid spherical samples: theory and a Monte Carlo simulation.

Science.gov (United States)

Otsuki, Soichi

2016-02-01

This paper presents a theory describing totally incoherent multiple scattering of turbid spherical samples. It is proved that if reciprocity and mirror symmetry hold for single scattering by a particle, they also hold for multiple scattering in spherical samples. Monte Carlo simulations generate a reduced effective scattering Mueller matrix, which virtually satisfies reciprocity and mirror symmetry. The scattering matrix was factorized by using the symmetric decomposition in a predefined form, as well as the Lu-Chipman polar decomposition, approximately into a product of a pure depolarizer and vertically oriented linear retarding diattenuators. The parameters of these components were calculated as a function of the polar angle. While the turbid spherical sample is a pure depolarizer at low polar angles, it obtains more functions of the retarding diattenuator with increasing polar angle.

All solid-state SBS phase conjugate mirror

Science.gov (United States)

Dane, C.B.; Hackel, L.A.

1999-03-09

A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases. 8 figs.

3D phase-shifting fringe projection system on the basis of a tailored free-form mirror.

Science.gov (United States)

Zwick, Susanne; Heist, Stefan; Steinkopf, Ralf; Huber, Sandra; Krause, Sylvio; Bräuer-Burchardt, Christian; Kühmstedt, Peter; Notni, Gunther

2013-05-10

Phase-shifting fringe projection is an effective method to perform 3D shape measurements. Conventionally, fringe projection systems utilize a digital projector that images fringes into the measurement plane. The performance of such systems is limited to the visible spectral range, as most projectors experience technical limitations in UV or IR spectral ranges. However, for certain applications these spectral ranges are of special interest. We present a wideband fringe projector that has been developed on the basis of a picture generating beamshaping mirror. This mirror generates a sinusoidal fringe pattern in the measurement plane without any additional optical elements. Phase shifting is realized without any mechanical movement by a multichip LED. As the system is based on a single mirror, it is wavelength-independent in a wide spectral range and therefore applicable in UV and IR spectral ranges. We present the design and a realized setup of this fringe projection system and the characterization of the generated intensity distribution. Experimental results of 3D shape measurements are presented.

On the theory of ultracold neutrons scattering by Davydov solitons

International Nuclear Information System (INIS)

Brizhik, L.S.

1984-01-01

Elastic coherent scattering of ultracold neutrons by Davydov solitons in one-dimensional periodic molecular chains without account of thermal oscillations of chain atoms is studied. It is shown that the expression for the differential cross section of the elastic neutron scattering by Davydov soliton breaks down into two components. One of them corresponds to scattering by a resting soliton, the other is proportional to the soliton velocity and has a sharp maximum in the direction of mirror reflection of neutrons from the chain

LUTE primary mirror materials and design study report

Science.gov (United States)

Ruthven, Greg

1993-02-01

The major objective of the Lunar Ultraviolet Telescope Experiment (LUTE) Primary Mirror Materials and Design Study is to investigate the feasibility of the LUTE telescope primary mirror. A systematic approach to accomplish this key goal was taken by first understanding the optical, thermal, and structural requirements and then deriving the critical primary mirror-level requirements for ground testing, launch, and lunar operations. After summarizing the results in those requirements which drove the selection of material and the design for the primary mirror are discussed. Most important of these are the optical design which was assumed to be the MSFC baseline (i.e. 3 mirror optical system), telescope wavefront error (WFE) allocations, the telescope weight budget, and the LUTE operational temperature ranges. Mechanical load levels, reflectance and microroughness issues, and options for the LUTE metering structure were discussed and an outline for the LUTE telescope sub-system design specification was initiated. The primary mirror analysis and results are presented. The six material substrate candidates are discussed and four distinct mirror geometries which are considered are shown. With these materials and configurations together with varying the location of the mirror support points, a total of 42 possible primary mirror designs resulted. The polishability of each substrate candidate was investigated and a usage history of 0.5 meter and larger precision cryogenic mirrors (the operational low end LUTE temperature of 60 K is the reason we feel a survey of cryogenic mirrors is appropriate) that were flown or tested are presented.

Target scattering characteristics for OAM-based radar

Directory of Open Access Journals (Sweden)

Kang Liu

2018-02-01

Full Text Available The target scattering characteristics are crucial for radar systems. However, there is very little study conducted for the recently developed orbital angular momentum (OAM based radar system. To illustrate the role of OAM-based radar cross section (ORCS, conventional radar equation is modified by taking characteristics of the OAM waves into account. Subsequently, the ORCS is defined in analogy to classical radar cross section (RCS. The unique features of the incident OAM-carrying field are analyzed. The scattered field is derived, and the analytical expressions of ORCSs for metal plate and cylinder targets are obtained. Furthermore, the ORCS and RCS are compared to illustrate the influences of OAM mode number, target size and signal frequency on the ORCS. Analytical studies demonstrate that the mirror-reflection phenomenon disappears and peak values of ORCS are in the non-specular direction. Finally, the ORCS features are summarized to show its advantages in radar target detection. This work can provide theoretical guidance to the design of OAM-based radar as well as the target detection and identification applications.

Target scattering characteristics for OAM-based radar

Science.gov (United States)

Liu, Kang; Gao, Yue; Li, Xiang; Cheng, Yongqiang

2018-02-01

The target scattering characteristics are crucial for radar systems. However, there is very little study conducted for the recently developed orbital angular momentum (OAM) based radar system. To illustrate the role of OAM-based radar cross section (ORCS), conventional radar equation is modified by taking characteristics of the OAM waves into account. Subsequently, the ORCS is defined in analogy to classical radar cross section (RCS). The unique features of the incident OAM-carrying field are analyzed. The scattered field is derived, and the analytical expressions of ORCSs for metal plate and cylinder targets are obtained. Furthermore, the ORCS and RCS are compared to illustrate the influences of OAM mode number, target size and signal frequency on the ORCS. Analytical studies demonstrate that the mirror-reflection phenomenon disappears and peak values of ORCS are in the non-specular direction. Finally, the ORCS features are summarized to show its advantages in radar target detection. This work can provide theoretical guidance to the design of OAM-based radar as well as the target detection and identification applications.

Ballooning instabilities in toroidally linked mirror systems

International Nuclear Information System (INIS)

Hastie, R.J.; Watson, C.J.H.

1977-01-01

This paper examines the stability against ballooning modes of plasma equilibria in toroidally linked mirror configurations consisting of a number of quadrupole minimum-B mirrors linked toroidally. On the basis of the Kruskal-Oberman energy principle, a class of displacements is identified which are potentially unstable, and a necessary criterion for stability is derived. The criterion is obtained from the eigenvalues of an ordinary differential equation, which determines the variation of the displacement along a field line. The coefficients in the equation are determined by the configuration, and by inserting various model configurations, estimates are obtained of the maximum value of β consistent with stability. In cases of interest, quite high β-values are obtained. (author)

Facial expressions : What the mirror neuron system can and cannot tell us

NARCIS (Netherlands)

van der Gaag, Christiaan; Minderaa, Ruud B.; Keysers, Christian

2007-01-01

Facial expressions contain both motor and emotional components. The inferior frontal gyrus (IFG) and posterior parietal cortex have been considered to compose a mirror neuron system (MNS) for the motor components of facial expressions, while the amygdala and insula may represent an "additional" MNS

Mirror neuron system based therapy for emotional disorders.

Science.gov (United States)

Yuan, Ti-Fei; Hoff, Robert

2008-11-01

Mirror neuron system (MNS) represents one of the most important discoveries in the area of neuropsychology of past decades. More than 500 papers have been published in this area (PubMed), and the major functions of MNS include action understanding, imitation, empathy, all of which are critical for an individual to be social. Recent studies suggested that MNS can modulate emotion states possibly through the empathy mechanism. Here we propose that MNS-based therapies provide a non-invasive approach in treatments to emotional disorders that were observed in autism patients, post-stroke patients with depression as well as other mood dysregulation conditions.

Adaptive metal mirror for high-power CO2 lasers

Science.gov (United States)

Jarosch, Uwe-Klaus

1996-08-01

Spherical mirrors with a variable radius of curvature are used inside laser resonators as well as in the beam path between the laser and the workpiece. Commercially-available systems use piezoelectric actuators, or the pressure of the coolant, to deform the mirror surface. In both cases, the actuator and the cooling system influence each other. This interaction is avoided through the integration of the cooling system with the flexible mirror membrane. A multi- channel design leads to an optimized cooling effect, which is necessary for high power applications. The contour of the variable metal mirror depends on the mounting between the membrane and the mirror body and on the distribution of forces. Four cases of deformation can be distinguished for a circular elastic membrane. The realization of an adaptive metal mirror requires a technical compromise to be made. A mechanical construction is presented which combines an elastic hinge with the inlet and outlet of the coolant. For the deformation of the mirror membranes two actuators with different character of deformation are used. The superposition of the two deformations results in smaller deviations from the spherical surface shape than can be achieved using a single actuator. DC proportional magnets have been introduced as cheap and rigid actuators. The use of this adaptive mirror, either in a low pressure atmosphere of a gas laser resonator, or in an extra-cavity beam path is made possible through the use of a ventilation system.

FMRI evidence of 'mirror' responses to geometric shapes.

Directory of Open Access Journals (Sweden)

Clare Press

Full Text Available Mirror neurons may be a genetic adaptation for social interaction. Alternatively, the associative hypothesis proposes that the development of mirror neurons is driven by sensorimotor learning, and that, given suitable experience, mirror neurons will respond to any stimulus. This hypothesis was tested using fMRI adaptation to index populations of cells with mirror properties. After sensorimotor training, where geometric shapes were paired with hand actions, BOLD response was measured while human participants experienced runs of events in which shape observation alternated with action execution or observation. Adaptation from shapes to action execution, and critically, observation, occurred in ventral premotor cortex (PMv and inferior parietal lobule (IPL. Adaptation from shapes to execution indicates that neuronal populations responding to the shapes had motor properties, while adaptation to observation demonstrates that these populations had mirror properties. These results indicate that sensorimotor training induced populations of cells with mirror properties in PMv and IPL to respond to the observation of arbitrary shapes. They suggest that the mirror system has not been shaped by evolution to respond in a mirror fashion to biological actions; instead, its development is mediated by stimulus-general processes of learning within a system adapted for visuomotor control.

Application of MEMS Accelerometers and Gyroscopes in Fast Steering Mirror Control Systems

Directory of Open Access Journals (Sweden)

Jing Tian

2016-03-01

Full Text Available In a charge-coupled device (CCD-based fast steering mirror (FSM tracking control system, high control bandwidth is the most effective way to enhance the closed-loop performance. However, the control system usually suffers a great deal from mechanical resonances and time delays induced by the low sampling rate of CCDs. To meet the requirements of high precision and load restriction, fiber-optic gyroscopes (FOGs are usually used in traditional FSM tracking control systems. In recent years, the MEMS accelerometer and gyroscope are becoming smaller and lighter and their performance have improved gradually, so that they can be used in a fast steering mirror (FSM to realize the stabilization of the line-of-sight (LOS of the control system. Therefore, a tentative approach to implement a CCD-based FSM tracking control system, which uses MEMS accelerometers and gyroscopes as feedback components and contains an acceleration loop, a velocity loop and a position loop, is proposed. The disturbance suppression of the proposed method is the product of the error attenuation of the acceleration loop, the velocity loop and the position loop. Extensive experimental results show that the MEMS accelerometers and gyroscopes can act the similar role as the FOG with lower cost for stabilizing the LOS of the FSM tracking control system.

Using geometric algebra to understand pattern rotations in multiple mirror optical systems

International Nuclear Information System (INIS)

Hanlon, J.; Ziock, H.

1997-01-01

Geometric Algebra (GA) is a new formulation of Clifford Algebra that includes vector analysis without notation changes. Most applications of Ga have been in theoretical physics, but GA is also a very good analysis tool for engineering. As an example, the authors use GA to study pattern rotation in optical systems with multiple mirror reflections. The common ways to analyze pattern rotations are to use rotation matrices or optical ray trace codes, but these are often inconvenient. The authors use GA to develop a simple expression for pattern rotation that is useful for designing or tolerancing pattern rotations in a multiple mirror optical system by inspection. Pattern rotation is used in many optical engineering systems, but it is not normally covered in optical system engineering texts. Pattern rotation is important in optical systems such as: (1) the 192 beam National ignition Facility (NIF), which uses square laser beams in close packed arrays to cut costs; (2) visual optical systems, which use pattern rotation to present the image to the observer in the appropriate orientation, and (3) the UR90 unstable ring resonator, which uses pattern rotation to fill a rectangular laser gain region and provide a filled-in laser output beam

Single-photon switch: Controllable scattering of photons inside a one-dimensional resonator waveguide

Science.gov (United States)

Zhou, L.; Gong, Z. R.; Liu, Y. X.; Sun, C. P.; Nori, F.

2010-03-01

We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. References: L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons inside a one-dimensional resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). L. Zhou, H. Dong, Y.X. Liu, C.P. Sun, F. Nori, Quantum super-cavity with atomic mirrors, Phys. Rev. A 78, 063827 (2008).

Design of an optimized adaptive optics system with a photo-controlled deformable mirror

Czech Academy of Sciences Publication Activity Database

Pilař, Jan; Bonora, Stefano; Lucianetti, Antonio; Jelínková, H.; Mocek, Tomáš

2016-01-01

Roč. 28, č. 13 (2016), s. 1422-1425 ISSN 1041-1135 Institutional support: RVO:68378271 Keywords : adaptive optics * closed loop systems * deformable mirror Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.375, year: 2016

Morphological differences in the mirror neuron system in Williams Syndrome

OpenAIRE

Ng, Rowena; Brown, Timothy T.; Erhart, Matthew; Järvinen, Anna M.; Korenberg, Julie R.; Bellugi, Ursula; Halgren, Eric

2015-01-01

Williams syndrome (WS) is a genetic condition characterized by an overly gregarious personality, including high empathetic concern for others. Although seemingly disparate from the profile of autism spectrum disorder (ASD), both are associated with deficits in social communication/cognition. Notably, the mirror neuron system (MNS) has been implicated in social dysfunction for ASD; yet, the integrity of this network and its association with social functioning in WS remains unknown. Magnetic re...

Tunable system for production of mirror and cusp configurations using chassis of permanent magnets

Science.gov (United States)

Hyde, Alexander; Bushmelov, Maxim; Batishchev, Oleg

2018-03-01

Compact arrays of permanent magnets have shown promise as replacements for electromagnets in applications requiring magnetic cusps and mirrors. An adjustable system capable of suspending and translating a pair of light, nonmagnetic chassis carrying such sources of magnetic field has been designed and constructed. Using this device to align two cylindrical chassis, strong solenoid-like domains of field, as well as classic biconic cusp and magnetic mirror topologies, are generated. Employing a pair of ring-shaped chassis instead, the superposition of their naturally-emitted cusps is demonstrated to produce sextupolar and octupolar magnetic fields.

[Mirror neurons: from anatomy to pathophysiological and therapeutic implications].

Science.gov (United States)

Mathon, B

2013-04-01

Mirror neurons are a special class of neurons discovered in the 1990s. They respond when we perform an action and also when we see someone else perform that action. They play a role in the pathophysiology of some neuropsychiatric diseases. Mirror neurons have been identified in humans: in Broca's area and the inferior parietal cortex. Their responses are qualitative and selective depending on the observed action. Emotions (including disgust) and empathy seem to operate according to a mirror mechanism. Indeed, the mirror system allows us to encode the sensory experience and to simulate the emotional state of others. This results in our improved identification of the emotions in others. Additionally, mirror neurons can encode an observed action in motor stimuli and allow its reproduction; thus, they are involved in imitation and learning. Current studies are assessing the role of mirror neurons in the pathopysiology of social-behavior disorders, including autism and schizophrenia. Understanding this mirror system will allow us to develop psychotherapy practices based on empathic resonance between the patient and the therapist. Also, some authors report that a passive rehabilitation technique, based on stimulation of the mirror-neuron system, has a beneficial effect in the treatment of patients with post-stroke motor deficits. Mirror neurons are an anatomical entity that enables improved understanding of behavior and emotions, and serves as a base for developing new cognitive therapies. Additional studies are needed to clarify the exact role of this neuronal system in social cognition and its role in the development of some neuropsychiatric diseases. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Speaking with a mirror: engagement of mirror neurons via choral speech and its derivatives induces stuttering inhibition.

Science.gov (United States)

Kalinowski, Joseph; Saltuklaroglu, Tim

2003-04-01

'Choral speech', 'unison speech', or 'imitation speech' has long been known to immediately induce reflexive, spontaneous, and natural sounding fluency, even the most severe cases of stuttering. Unlike typical post-therapeutic speech, a hallmark characteristic of choral speech is the sense of 'invulnerability' to stuttering, regardless of phonetic context, situational environment, or audience size. We suggest that choral speech immediately inhibits stuttering by engaging mirror systems of neurons, innate primitive neuronal substrates that dominate the initial phases of language development due to their predisposition to reflexively imitate gestural action sequences in a fluent manner. Since mirror systems are primordial in nature, they take precedence over the much later developing stuttering pathology. We suggest that stuttering may best be ameliorated by reengaging mirror neurons via choral speech or one of its derivatives (using digital signal processing technology) to provide gestural mirrors, that are nature's way of immediately overriding the central stuttering block. Copyright 2003 Elsevier Science Ltd.

Research on Measurement Accuracy of Laser Tracking System Based on Spherical Mirror with Rotation Errors of Gimbal Mount Axes

Science.gov (United States)

Shi, Zhaoyao; Song, Huixu; Chen, Hongfang; Sun, Yanqiang

2018-02-01

This paper presents a novel experimental approach for confirming that spherical mirror of a laser tracking system can reduce the influences of rotation errors of gimbal mount axes on the measurement accuracy. By simplifying the optical system model of laser tracking system based on spherical mirror, we can easily extract the laser ranging measurement error caused by rotation errors of gimbal mount axes with the positions of spherical mirror, biconvex lens, cat's eye reflector, and measuring beam. The motions of polarization beam splitter and biconvex lens along the optical axis and vertical direction of optical axis are driven by error motions of gimbal mount axes. In order to simplify the experimental process, the motion of biconvex lens is substituted by the motion of spherical mirror according to the principle of relative motion. The laser ranging measurement error caused by the rotation errors of gimbal mount axes could be recorded in the readings of laser interferometer. The experimental results showed that the laser ranging measurement error caused by rotation errors was less than 0.1 μm if radial error motion and axial error motion were within ±10 μm. The experimental method simplified the experimental procedure and the spherical mirror could reduce the influences of rotation errors of gimbal mount axes on the measurement accuracy of the laser tracking system.

Characterization of HR coatings for the megajoule laser transport mirrors

International Nuclear Information System (INIS)

Fornier, A.; Cordillot, C.; Bernardino, D.; Lam, O.; Roussel, A.

1997-01-01

One of the concerns with the Megajoule Laser design is the laser-induced damage threshold of the transport mirrors. Earlier studies have shown that the main constraint on the laser damage threshold comes from nodules at the mirror surface. It is therefore important to restrict the number of such nodules. SFIM-ODS, in close collaboration with CEL-V, has initiated a special study to characterize these nodules as precisely as possible. The objective of the study is twofold: (1) to determine the origin of the nodules and subsequently to adapt the mirror fabrication process in order to limit their formation, (2) to analyze their shapes and dimensions in order to ascertain which nodules are critical for laser-induced damage. To understand the origin of the nodules and their effect on the laser damage threshold, the mirrors are characterized using various methods, (3) absorption and scatter mapping: does the presence of nodules result in specific absorption patterns? (4) surface analysis by atomic force microscopy: to characterize nodule shape and dimensions, (5) Focused Ion Beam (FIB) cutting of nodules: to locate the seed initiating the nodule (on the substrate or in the stack), and to characterize the seed shape and composition (contamination, material spatter during evaporation, etc.), and (6) laser damage threshold measurements: to determine the laser damage threshold of the mirror and study the behavior of nodules under laser irradiation depending on their dimensions and shape

Mirror neurons: from origin to function.

Science.gov (United States)

Cook, Richard; Bird, Geoffrey; Catmur, Caroline; Press, Clare; Heyes, Cecilia

2014-04-01

This article argues that mirror neurons originate in sensorimotor associative learning and therefore a new approach is needed to investigate their functions. Mirror neurons were discovered about 20 years ago in the monkey brain, and there is now evidence that they are also present in the human brain. The intriguing feature of many mirror neurons is that they fire not only when the animal is performing an action, such as grasping an object using a power grip, but also when the animal passively observes a similar action performed by another agent. It is widely believed that mirror neurons are a genetic adaptation for action understanding; that they were designed by evolution to fulfill a specific socio-cognitive function. In contrast, we argue that mirror neurons are forged by domain-general processes of associative learning in the course of individual development, and, although they may have psychological functions, they do not necessarily have a specific evolutionary purpose or adaptive function. The evidence supporting this view shows that (1) mirror neurons do not consistently encode action "goals"; (2) the contingency- and context-sensitive nature of associative learning explains the full range of mirror neuron properties; (3) human infants receive enough sensorimotor experience to support associative learning of mirror neurons ("wealth of the stimulus"); and (4) mirror neurons can be changed in radical ways by sensorimotor training. The associative account implies that reliable information about the function of mirror neurons can be obtained only by research based on developmental history, system-level theory, and careful experimentation.

Flexural-Phonon Scattering Induced by Electrostatic Gating in Graphene

DEFF Research Database (Denmark)

Gunst, Tue; Kaasbjerg, Kristen; Brandbyge, Mads

2017-01-01

Graphene has an extremely high carrier mobility partly due to its planar mirror symmetry inhibiting scattering by the highly occupied acoustic flexural phonons. Electrostatic gating of a graphene device can break the planar mirror symmetry, yielding a coupling mechanism to the flexural phonons......-limiting factor, and show how the carrier density and temperature scaling of the mobility depends on the electrostatic environment. Our findings may explain the high deformation potential for in-plane acoustic phonons extracted from experiments and, furthermore, suggest a direct relation between device symmetry...

Highly efficient end-side-pumped Nd:YAG solar laser by a heliostat-parabolic mirror system.

Science.gov (United States)

Almeida, J; Liang, D; Vistas, C R; Guillot, E

2015-03-10

We report a large improvement in the collection and slope efficiency of an Nd:YAG solar laser pumped by a heliostat-parabolic mirror system. A conical fused silica lens was used to further concentrate the solar radiation from the focal zone of a 2 m diameter primary concentrator to a Nd:YAG single-crystal rod within a conical pump cavity, which enabled multipass pumping to the active medium. A 56 W cw laser power was measured, corresponding to 21.1  W/m2 record-high solar laser collection efficiency with the heliostat-parabolic mirror system. 4.9% slope efficiency was calculated, corresponding to 175% enhancement over our previous result.

Mirror therapy: A potential intervention for pain management

Directory of Open Access Journals (Sweden)

Priscilla G. Wittkopf

Full Text Available Summary The consequences of chronic pain and associated disabilities to the patient and to the health care system are well known. Medication is often the first treatment of choice for chronic pain, although side effects and high costs restrict long-term use. Inexpensive, safe and easy to self-administer non-pharmacological therapies, such as mirror therapy, are recommended as adjuncts to pain treatment. The purpose of this review is to describe the principles of use of mirror therapy so it can be incorporated into a health care delivery. The physiological rationale of mirror therapy for the management of pain and the evidence of clinical efficacy based on recent systematic reviews are also discussed. Mirror therapy, whereby a mirror is placed in a position so that the patient can view a reflection of a body part, has been used to treat phantom limb pain, complex regional pain syndrome, neuropathy and low back pain. Research evidence suggests that a course of treatment (four weeks of mirror therapy may reduce chronic pain. Contraindications and side effects are few. The mechanism of action of mirror therapy remains uncertain, with reintegration of motor and sensory systems, restored body image and control over fear-avoidance likely to influence outcome. The evidence for clinical efficacy of mirror therapy is encouraging, but not yet definitive. Nevertheless, mirror therapy is inexpensive, safe and easy for the patient to self-administer.

Scattered radiation in fan beam imaging systems

International Nuclear Information System (INIS)

Johns, P.C.; Yaffe, M.

1982-01-01

Scatter-to-primary energy fluence ratios (S/P) have been studied for fan x-ray beams as used in CT scanners and slit projection radiography systems. The dependence of S/P on phantom diameter, distance from phantom to image receptor, and kilovoltage is presented. An empirical equation is given that predicts S/P over a wide range of fan beam imaging configurations. For CT body scans on a 4th-generation machine, S/P is approximately 5%. Scattered radiation can produce a significant cupping artefact in CT images which is similar to that due to beam hardening. When multiple slices are used in scanned slit radiography, they can be arranged such that the increase in S/P is negligible. Calculations of scatter-to-primary ratios for first order scattering showed that for fan beams the contribution of coherent scatter is comparable to or greater than that of incoherent first scatter

Relativistic electron mirrors from high intensity laser nanofoil interactions

Energy Technology Data Exchange (ETDEWEB)

Kiefer, Daniel

2012-12-21

The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ{sup 2}, where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those

The Gasdynamic Mirror Fusion Propulsion System -- Revisited

International Nuclear Information System (INIS)

Kammash, Terry; Tang, Ricky

2005-01-01

Many of the previous studies assessing the capability of the gasdynamic mirror (GDM) fusion propulsion system employed analyses that ignored the 'ambipolar' potential. This electrostatic potential arises as a result of the rapid escape of the electrons due to their small mass. As they escape, they leave behind an excess positive charge which manifests itself in an electric field that slows down the electrons while speeding up the ions until their respective axial diffusions are equalized. The indirect effect on the ions is that their confinement time is reduced relative to that of zero potential, and hence the plasma length must be increased to accommodate that change. But as they emerge from the thruster mirror - which serves as a magnetic nozzle - the ions acquire an added energy equal to that of the potential energy, and that in turn manifests itself in increased specific impulse and thrust. We assess the propulsive performance of the GDM thruster, based on the more rigorous theory, by applying it to a round trip Mars mission employing a continuous burn acceleration/deceleration type of trajectory. We find that the length of the device and travel time decrease with increasing plasma density, while the total vehicle mass reaches a minimum at a plasma density of 3 x 1016 cm-3. At such a density, and an initial DT ion temperature of 10 keV, a travel time of 60 days is found to be achievable at GDM propulsion parameters of about 200,000 seconds of specific impulse and approximately 47 kN of thrust

Mirror Me: Imitative Responses in Adults with Autism

Science.gov (United States)

Schunke, Odette; Schöttle, Daniel; Vettorazzi, Eik; Brandt, Valerie; Kahl, Ursula; Bäumer, Tobias; Ganos, Christos; David, Nicole; Peiker, Ina; Engel, Andreas K; Brass, Marcel; Münchau, Alexander

2016-01-01

Dysfunctions of the human mirror neuron system have been postulated to underlie some deficits in autism spectrum disorders including poor imitative performance and impaired social skills. Using three reaction time experiments addressing mirror neuron system functions under simple and complex conditions, we examined 20 adult autism spectrum…

PLANET-PLANET SCATTERING LEADS TO TIGHTLY PACKED PLANETARY SYSTEMS

International Nuclear Information System (INIS)

Raymond, Sean N.; Barnes, Rory; Veras, Dimitri; Armitage, Philip J.; Gorelick, Noel; Greenberg, Richard

2009-01-01

The known extrasolar multiple-planet systems share a surprising dynamical attribute: they cluster just beyond the Hill stability boundary. Here we show that the planet-planet scattering model, which naturally explains the observed exoplanet eccentricity distribution, can reproduce the observed distribution of dynamical configurations. We calculated how each of our scattered systems would appear over an appropriate range of viewing geometries; as Hill stability is weakly dependent on the masses, the mass-inclination degeneracy does not significantly affect our results. We consider a wide range of initial planetary mass distributions and find that some are poor fits to the observed systems. In fact, many of our scattering experiments overproduce systems very close to the stability boundary. The distribution of dynamical configurations of two-planet systems may provide better discrimination between scattering models than the distribution of eccentricity. Our results imply that, at least in their inner regions which are weakly affected by gas or planetesimal disks, planetary systems should be 'packed', with no large gaps between planets.

Outgoing Cuntz scattering system for a coisometric lifting and ...

Indian Academy of Sciences (India)

Multivariate operator theory; row contraction; contractive lifting; outgoing. Cuntz scattering system ... multivariate operator setting. In § 3 we study the ..... Our goal is to find an outgoing Cuntz scattering system inside our model. Let as before.

A real-space renormalization approach to the Kubo-Greenwood formula in mirror Fibonacci systems

International Nuclear Information System (INIS)

Sanchez, Vicenta; Wang Chumin

2006-01-01

An exact real-space renormalization method is developed to address the electronic transport in mirror Fibonacci chains at a macroscopic scale by means of the Kubo-Greenwood formula. The results show that the mirror symmetry induces a large number of transparent states in the dc conductivity spectra, contrary to the simple Fibonacci case. A length scaling analysis over ten orders of magnitude reveals the existence of critically localized states and their ac conduction spectra show a highly oscillating behaviour. For multidimensional quasiperiodic systems, a novel renormalization plus convolution method is proposed. This combined renormalization + convolution method has shown an extremely elevated computing efficiency, being able to calculate electrical conductance of a three-dimensional non-crystalline solid with 10 30 atoms. Finally, the dc and ac conductances of mirror Fibonacci nanowires are also investigated, where a quantized dc-conductance variation with the Fermi energy is found, as observed in gold nanowires

Design of the GOES Telescope secondary mirror mounting

Science.gov (United States)

Hookman, Robert A.

1989-01-01

The GOES Telescope utilizes a flexure mounting system for the secondary mirror to minimize thermally induced distortions of the secondary mirror. The detailed design is presented along with a discussion of the microradian pointing requirements and how they were achieved. The methodology used to dynamically tune the flexure/secondary mirror assembly to minimize structural interactions will also be discussed.

The mirror-neuron system and observational learning: Implications for the effectiveness of dynamic visualizations.

OpenAIRE

Van Gog, Tamara; Paas, Fred; Marcus, Nadine; Ayres, Paul; Sweller, John

2009-01-01

Van Gog, T., Paas, F., Marcus, N., Ayres, P., & Sweller, J. (2009). The mirror-neuron system and observational learning: Implications for the effectiveness of dynamic visualizations. Educational Psychology Review, 21, 21-30.

Using Mu Rhythm Desynchronization to Measure Mirror Neuron Activity in Infants

Science.gov (United States)

Nystrom, Par; Ljunghammar, Therese; Rosander, Kerstin; von Hofsten, Claes

2011-01-01

The Mirror Neuron System hypothesis stating that observed actions are projected onto the observer's own action system assigns an important role to development, because only actions mastered by the observer can be mirrored. The purpose of the present study was to investigate whether there is evidence of a functioning mirror neuron system (MNS) in…

Action observation: Inferring intentions without mirror neurons

DEFF Research Database (Denmark)

Frith, Christopher; Kilner, James M

2008-01-01

A recent study has shown, using fMRI, that the mirror neuron system does not mediate action understanding when the observed action is novel or when it is hard to understand.......A recent study has shown, using fMRI, that the mirror neuron system does not mediate action understanding when the observed action is novel or when it is hard to understand....

Onset of superradiant instabilities in the composed Kerr-black-hole–mirror bomb

Directory of Open Access Journals (Sweden)

Shahar Hod

2014-09-01

Full Text Available It was first pointed out by Press and Teukolsky that a system composed of a spinning Kerr black hole surrounded by a reflecting mirror may develop instabilities. The physical mechanism responsible for the development of these exponentially growing instabilities is the superradiant amplification of bosonic fields confined between the black hole and the mirror. A remarkable feature of this composed black-hole–mirror-field system is the existence of a critical mirror radius, rmstat, which supports stationary (marginally-stable field configurations. This critical (‘stationary’ mirror radius marks the boundary between stable and unstable black-hole–mirror-field configurations: composed systems whose confining mirror is situated in the region rmrmstat are unstable (that is, there are confined field modes which grow exponentially over time. In the present paper we explore this critical (marginally-stable boundary between stable and explosive black-hole–mirror-field configurations. It is shown that the innermost (smallest radius of the confining mirror which allows the extraction of rotational energy from a spinning Kerr black hole approaches the black-hole horizon radius in the extremal limit of rapidly-rotating black holes. We find, in particular, that this critical mirror radius (which marks the onset of superradiant instabilities in the composed system scales linearly with the black-hole temperature.

Fast force actuators for LSST primary/tertiary mirror

Science.gov (United States)

Hileman, Edward; Warner, Michael; Wiecha, Oliver

2010-07-01

The very short slew times and resulting high inertial loads imposed upon the Large Synoptic Survey Telescope (LSST) create new challenges to the primary mirror support actuators. Traditionally large borosilicate mirrors are supported by pneumatic systems, which is also the case for the LSST. These force based actuators bear the weight of the mirror and provide active figure correction, but do not define the mirror position. A set of six locating actuators (hardpoints) arranged in a hexapod fashion serve to locate the mirror. The stringent dynamic requirements demand that the force actuators must be able to counteract in real time for dynamic forces on the hardpoints during slewing to prevent excessive hardpoint loads. The support actuators must also maintain the prescribed forces accurately during tracking to maintain acceptable mirror figure. To meet these requirements, candidate pneumatic cylinders incorporating force feedback control and high speed servo valves are being tested using custom instrumentation with automatic data recording. Comparative charts are produced showing details of friction, hysteresis cycles, operating bandwidth, and temperature dependency. Extremely low power actuator controllers are being developed to avoid heat dissipation in critical portions of the mirror and also to allow for increased control capabilities at the actuator level, thus improving safety, performance, and the flexibility of the support system.

Linear systems formulation of scattering theory for rough surfaces with arbitrary incident and scattering angles.

Science.gov (United States)

Krywonos, Andrey; Harvey, James E; Choi, Narak

2011-06-01

Scattering effects from microtopographic surface roughness are merely nonparaxial diffraction phenomena resulting from random phase variations in the reflected or transmitted wavefront. Rayleigh-Rice, Beckmann-Kirchhoff. or Harvey-Shack surface scatter theories are commonly used to predict surface scatter effects. Smooth-surface and/or paraxial approximations have severely limited the range of applicability of each of the above theoretical treatments. A recent linear systems formulation of nonparaxial scalar diffraction theory applied to surface scatter phenomena resulted first in an empirically modified Beckmann-Kirchhoff surface scatter model, then a generalized Harvey-Shack theory that produces accurate results for rougher surfaces than the Rayleigh-Rice theory and for larger incident and scattered angles than the classical Beckmann-Kirchhoff and the original Harvey-Shack theories. These new developments simplify the analysis and understanding of nonintuitive scattering behavior from rough surfaces illuminated at arbitrary incident angles.

Modeling of biaxial gimbal-less MEMS scanning mirrors

Science.gov (United States)

von Wantoch, Thomas; Gu-Stoppel, Shanshan; Senger, Frank; Mallas, Christian; Hofmann, Ulrich; Meurer, Thomas; Benecke, Wolfgang

2016-03-01

One- and two-dimensional MEMS scanning mirrors for resonant or quasi-stationary beam deflection are primarily known as tiny micromirror devices with aperture sizes up to a few Millimeters and usually address low power applications in high volume markets, e.g. laser beam scanning pico-projectors or gesture recognition systems. In contrast, recently reported vacuum packaged MEMS scanners feature mirror diameters up to 20 mm and integrated high-reflectivity dielectric coatings. These mirrors enable MEMS based scanning for applications that require large apertures due to optical constraints like 3D sensing or microscopy as well as for high power laser applications like laser phosphor displays, automotive lighting and displays, 3D printing and general laser material processing. This work presents modelling, control design and experimental characterization of gimbal-less MEMS mirrors with large aperture size. As an example a resonant biaxial Quadpod scanner with 7 mm mirror diameter and four integrated PZT (lead zirconate titanate) actuators is analyzed. The finite element method (FEM) model developed and computed in COMSOL Multiphysics is used for calculating the eigenmodes of the mirror as well as for extracting a high order (n system inputs and scanner displacement as system output. By applying model order reduction techniques using MATLABR a compact state space system approximation of order n = 6 is computed. Based on this reduced order model feedforward control inputs for different, properly chosen scanner displacement trajectories are derived and tested using the original FEM model as well as the micromirror.

A 40 W cw Nd:YAG solar laser pumped through a heliostat: a parabolic mirror system

International Nuclear Information System (INIS)

Almeida, J; Liang, D; Guillot, E; Abdel-Hadi, Y

2013-01-01

Solar-pumped solid-state lasers are promising for renewable extreme-temperature material processing. Here, we report a significant improvement in solar laser collection efficiency by pumping the most widely used Nd:YAG single-crystal rod through a heliostat–parabolic mirror system. A conical-shaped fused silica light guide with 3D-CPC output end is used to both transmit and compress the concentrated solar radiation from the focal zone of a 2 m diameter parabolic mirror to a 5 mm diameter Nd:YAG rod within a conical pump cavity, which enables multi-pass pumping through the laser rod. 40 W cw laser power is measured, corresponding to 13.9 W m −2 record-high collection efficiency for the solar laser pumped through a heliostat–parabolic mirror system. 2.9% slope efficiency is fitted, corresponding to 132% enhancement over that of our previous pumping scheme. A 209% reduction in threshold pump power is also registered. (paper)

Three-mirror anastigmat for cosmic microwave background observations.

Science.gov (United States)

Padin, S

2018-03-20

An off-axis three-mirror anastigmat is proposed for future cosmic microwave background observations. The telescope has a 5 m diameter primary, giving 1.5 ' angular resolution at λ=2  mm, which is sufficient for measurements of gravitational lensing and for galaxy cluster surveys. The design includes several key features, not previously combined in a large telescope, that are important for sensitive measurements, especially on large angular scales: (1) high throughput (8° diameter diffraction-limited field of view at λ=1  mm, and 12×8° at λ=3  mm, so a single telescope could support all the detectors for an optimistic, future experiment); (2) low scattering (all the mirrors are small enough to be monolithic, so there are no segment gaps); (3) full boresight rotation, over the full elevation range, for measuring polarization errors; and (4) a comoving shield or baffle around the entire telescope to control pickup.

Mirror neurons and their clinical relevance.

Science.gov (United States)

Rizzolatti, Giacomo; Fabbri-Destro, Maddalena; Cattaneo, Luigi

2009-01-01

One of the most exciting events in neurosciences over the past few years has been the discovery of a mechanism that unifies action perception and action execution. The essence of this 'mirror' mechanism is as follows: whenever individuals observe an action being done by someone else, a set of neurons that code for that action is activated in the observers' motor system. Since the observers are aware of the outcome of their motor acts, they also understand what the other individual is doing without the need for intermediate cognitive mediation. In this Review, after discussing the most pertinent data concerning the mirror mechanism, we examine the clinical relevance of this mechanism. We first discuss the relationship between mirror mechanism impairment and some core symptoms of autism. We then outline the theoretical principles of neurorehabilitation strategies based on the mirror mechanism. We conclude by examining the relationship between the mirror mechanism and some features of the environmental dependency syndromes.

Einstein's Mirror

Science.gov (United States)

Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

2008-01-01

Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity. The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a…

Performance of lightweight large C/SiC mirror

Science.gov (United States)

Yui, Yukari Y.; Goto, Ken; Kaneda, Hidehiro; Katayama, Haruyoshi; Kotani, Masaki; Miyamoto, Masashi; Naitoh, Masataka; Nakagawa, Takao; Saruwatari, Hideki; Suganuma, Masahiro; Sugita, Hiroyuki; Tange, Yoshio; Utsunomiya, Shin; Yamamoto, Yasuji; Yamawaki, Toshihiko

2017-11-01

Very lightweight mirror will be required in the near future for both astronomical and earth science/observation missions. Silicon carbide is becoming one of the major materials applied especially to large and/or light space-borne optics, such as Herschel, GAIA, and SPICA. On the other hand, the technology of highly accurate optical measurement of large telescopes, especially in visible wavelength or cryogenic circumstances is also indispensable to realize such space-borne telescopes and hence the successful missions. We have manufactured a very lightweight Φ=800mm mirror made of carbon reinforced silicon carbide composite that can be used to evaluate the homogeneity of the mirror substrate and to master and establish the ground testing method and techniques by assembling it as the primary mirror into an optical system. All other parts of the optics model are also made of the same material as the primary mirror. The composite material was assumed to be homogeneous from the mechanical tests of samples cut out from the various areas of the 800mm mirror green-body and the cryogenic optical measurement of the mirror surface deformation of a 160mm sample mirror that is also made from the same green-body as the 800mm mirror. The circumstance and condition of the optical testing facility has been confirmed to be capable for the highly precise optical measurements of large optical systems of horizontal light axis configuration. Stitching measurement method and the algorithm for analysis of the measurement is also under study.

Adaptive Optics System with Deformable Composite Mirror and High Speed, Ultra-Compact Electronics

Science.gov (United States)

Chen, Peter C.; Knowles, G. J.; Shea, B. G.

2006-06-01

We report development of a novel adaptive optics system for optical astronomy. Key components are very thin Deformable Mirrors (DM) made of fiber reinforced polymer resins, subminiature PMN-PT actuators, and low power, high bandwidth electronics drive system with compact packaging and minimal wiring. By using specific formulations of fibers, resins, and laminate construction, we are able to fabricate mirror face sheets that are thin (2 KHz. By utilizing QorTek’s proprietary synthetic impendence power supply technology, all the power, control, and signal extraction for many hundreds to 1000s of actuators and sensors can be implemented on a single matrix controller printed circuit board co-mounted with the DM. The matrix controller, in turn requires only a single serial bus interface, thereby obviating the need for massive wiring harnesses. The technology can be scaled up to multi-meter aperture DMs with >100K actuators.

Mirror-based broadband scanner with minimized aberration

Science.gov (United States)

Yu, Jiun-Yann; Tzeng, Yu-Yi; Huang, Chen-Han; Chui, Hsiang-Chen; Chu, Shi-Wei

2009-02-01

To obtain specific biochemical information in optical scanning microscopy, labeling technique is routinely required. Instead of the complex and invasive sample preparation procedures, incorporating spectral acquisition, which commonly requires a broadband light source, provides another mechanism to enhance molecular contrast. But most current optical scanning system is lens-based and thus the spectral bandwidth is limited to several hundred nanometers due to anti-reflection coating and chromatic aberration. The spectral range of interest in biological research covers ultraviolet to infrared. For example, the absorption peak of water falls around 3 μm, while most proteins exhibit absorption in the UV-visible regime. For imaging purpose, the transmission window of skin and cerebral tissues fall around 1300 and 1800 nm, respectively. Therefore, to extend the spectral bandwidth of an optical scanning system from visible to mid-infrared, we propose a system composed of metallic coated mirrors. A common issue in such a mirror-based system is aberrations induced by oblique incidence. We propose to compensate astigmatism by exchanging the sagittal and tangential planes of the converging spherical mirrors in the scanning system. With the aid of an optical design software, we build a diffraction-limited broadband scanning system with wavefront flatness better than λ/4 at focal plane. Combined with a mirror-based objective this microscopic system will exhibit full spectral capability and will be useful in microscopic imaging and therapeutic applications.

Machine and plasma diagnostic instrumentation systems for the Tandem Mirror Experiment Upgrade

International Nuclear Information System (INIS)

Coutts, G.W.; Coffield, F.E.; Lang, D.D.; Hornady, R.S.

1981-01-01

To evaluate performance of a second generation Tandem Mirror Machine, an extensive instrumentation system is being designed and installed as part of the major device fabrication. The systems listed will be operational during the start-up phase of the TMX Upgrade machine and provide bench marks for future performance data. In addition to plasma diagnostic instrumentation, machine parameter monitoring systems will be installed prior to machine operation. Simultaneous recording of machine parameters will permit evaluation of plasma parameters sensitive to machine conditions

Onset of superradiant instabilities in the composed Kerr-black-hole–mirror bomb

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emeq Hefer 40250 (Israel); The Hadassah Institute, Jerusalem 91010 (Israel)

2014-09-07

It was first pointed out by Press and Teukolsky that a system composed of a spinning Kerr black hole surrounded by a reflecting mirror may develop instabilities. The physical mechanism responsible for the development of these exponentially growing instabilities is the superradiant amplification of bosonic fields confined between the black hole and the mirror. A remarkable feature of this composed black-hole–mirror-field system is the existence of a critical mirror radius, r{sub m}{sup stat}, which supports stationary (marginally-stable) field configurations. This critical (‘stationary’) mirror radius marks the boundary between stable and unstable black-hole–mirror-field configurations: composed systems whose confining mirror is situated in the region r{sub m}systems whose confining mirror is situated in the region r{sub m}>r{sub m}{sup stat} are unstable (that is, there are confined field modes which grow exponentially over time). In the present paper we explore this critical (marginally-stable) boundary between stable and explosive black-hole–mirror-field configurations. It is shown that the innermost (smallest) radius of the confining mirror which allows the extraction of rotational energy from a spinning Kerr black hole approaches the black-hole horizon radius in the extremal limit of rapidly-rotating black holes. We find, in particular, that this critical mirror radius (which marks the onset of superradiant instabilities in the composed system) scales linearly with the black-hole temperature.

Einstein's Mirror

Science.gov (United States)

Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

2008-10-01

Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity.1-4 The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a constant velocity.5 Einstein showed an intriguing fact that the usual law of reflection would not hold in the case of a uniformly moving mirror, that is, the angles of incidence and reflection of the light would not equal each other. Later on, it has been shown that the law of reflection at a moving mirror can be obtained in various alternative ways,6-10 but none of them seems suitable for bringing this interesting subject into the high school classroom.

System model for analysis of the mirror fusion-fission reactor

International Nuclear Information System (INIS)

Bender, D.J.; Carlson, G.A.

1977-01-01

This report describes a system model for the mirror fusion-fission reactor. In this model we include a reactor description as well as analyses of capital cost and blanket fuel management. In addition, we provide an economic analysis evaluating the cost of producing the two hybrid products, fissile fuel and electricity. We also furnish the results of a limited parametric analysis of the modeled reactor, illustrating the technological and economic implications of varying some important reactor design parameters

Mirror Advanced Reactor Study (MARS)

International Nuclear Information System (INIS)

Logan, B.G.

1983-01-01

Progress in a two year study of a 1200 MWe commercial tandem mirror reactor (MARS - Mirror Advanced Reactor Study) has reached the point where major reactor system technologies are identified. New design features of the magnets, blankets, plug heating systems and direct converter are described. With the innovation of radial drift pumping to maintain low plug density, reactor recirculating power fraction is reduced to 20%. Dominance of radial ion and impurity losses into the halo permits gridless, circular direct converters to be dramatically reduced in size. Comparisons of MARS with the Starfire tokamak design are made

Use of webcams as tools for alignment and supervision of a Thomson scattering system in the near infrared

Energy Technology Data Exchange (ETDEWEB)

Andrebe, Y., E-mail: yanis.andrebe@epfl.ch [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, Station 13, 1015 Lausanne (Switzerland); Behn, R.; Duval, B.P.; Etienne, P.; Pitzschke, A. [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, Station 13, 1015 Lausanne (Switzerland)

2011-10-15

The alignment stability is a major concern for Thomson scattering systems. Even small angular deviations of the laser beams crossing the plasma lead to a loss of the calibration resulting in unreliable measurements of the electron density profile. For the TCV (Tokamak a Configuration Variable) installation, the beam paths from the laser output to the vacuum chamber are {approx}25 m long and include several optical components. In order to monitor the alignment on a regular basis, a set of 9 cameras has been installed at several locations along the beam path. They view the actual laser beam pattern by recording the scattered light from an intercepting optical surface (mirror or window) together with the position of markers used for reference. Small 'webcams' are used for this purpose; they feature adequate intensity response at the laser wavelength of 1.06 {mu}m, are compact, cheap and several units may be connected to a server PC simultaneously. The real-time images from all the cameras are accessible from a Web browser. This installation has proven to be extremely useful in the early detection of alignment problems and to assist the alignment procedure .

Database mirroring in fault-tolerant continuous technological process control

Directory of Open Access Journals (Sweden)

R. Danel

2015-10-01

Full Text Available This paper describes the implementations of mirroring technology of the selected database systems – Microsoft SQL Server, MySQL and Caché. By simulating critical failures the systems behavior and their resilience against failure were tested. The aim was to determine whether the database mirroring is suitable to use in continuous metallurgical processes for ensuring the fault-tolerant solution at affordable cost. The present day database systems are characterized by high robustness and are resistant to sudden system failure. Database mirroring technologies are reliable and even low-budget projects can be provided with a decent fault-tolerant solution. The database system technologies available for low-budget projects are not suitable for use in real-time systems.

Amorphous Metals and Composites as Mirrors and Mirror Assemblies

Science.gov (United States)

Hofmann, Douglas C. (Inventor); Davis, Gregory L. (Inventor); Agnes, Gregory S. (Inventor); Shapiro, Andrew A. (Inventor)

2016-01-01

A mirror or mirror assembly fabricated by molding, pressing, assembling, or depositing one or more bulk metal glass (BMG), bulk metal glass composite (BMGMC), or amorphous metal (AM) parts and where the optical surface and backing of the mirror can be fabricated without machining or polishing by utilizing the unique molding capabilities of this class of materials.

Mirror machine reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Moir, R.W.

1976-01-01

Recent mirror reactor conceptual design studies are described. Considered in detail is the design of ''standard'' Yin-Yang fusion power reactors with classical and enhanced confinement. It is shown that to be economically competitive with estimates for other future energy sources, mirror reactors require a considerable increase in Q, or major design simplifications, or preferably both. These improvements may require a departure from the ''standard'' configuration. Two attractive possibilities, both of which would use much of the same physics and technology as the ''standard'' mirror, are the field reversed mirror and the end-stoppered mirror

A Research on the Primary Mirror Manipulator of Large Segmented-mirror Telescope

Science.gov (United States)

Zuo, H.

2012-09-01

Since Galileo firstly used the telescope to observe the sky 400 years ago, the aperture of the telescope has become larger and larger to observe the deeper universe, and the segmented-mirror telescope is becoming more and more popular with increasing aperture. In the early 21st century, a series of segmented-mirror telescopes have been constructed including the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) of China. LAMOST is a meridian reflecting Schmidt telescope, and the dimension of the primary mirror is about 6.7 m× 6 m, which is composed of 37 hexagonal sub-mirrors. However, a problem about the mirror installation appears with the increasing aperture. If there are hundreds of sub-mirrors in the telescope, it is a challenging job to mount and dismount them to the truss. This problem is discussed in this paper and a manipulator for the primary mirror of LAMOST is designed to perform the mount and dismount work. In chapter 1, all the segmented-mirror telescopes in the world are introduced and how the sub-mirrors of these telescopes are installed has been investigated. After comparing with the serial and the parallel robot, a serial robot manipulator proposal, which has several redundant degrees of freedom (DOFs), has been chosen from a series of design proposals. In chapter 2, the theoretical analysis has been carried out on the basis of the design proposal, which includes the forward kinematics and the inverse kinematics. Firstly the D-H coordinate is built according to the structure of the manipulator, so it is possible to obtain the end-effector position and orientation from the individual joint motion thanks to the forward kinematics. Because of the redundant DOFs of the manipulator, the inverse kinematics solution can be a very trick task, and the result may not be only, therefore a kind of simulation is carried out to get the numerical solution using ADAMS (Automatic Dynamic Analysis of Mechanical System). In the dynamics analysis the

Learning of spatial relationships between observed and imitated actions allows invariant inverse computation in the frontal mirror neuron system.

Science.gov (United States)

Oh, Hyuk; Gentili, Rodolphe J; Reggia, James A; Contreras-Vidal, José L

2011-01-01

It has been suggested that the human mirror neuron system can facilitate learning by imitation through coupling of observation and action execution. During imitation of observed actions, the functional relationship between and within the inferior frontal cortex, the posterior parietal cortex, and the superior temporal sulcus can be modeled within the internal model framework. The proposed biologically plausible mirror neuron system model extends currently available models by explicitly modeling the intraparietal sulcus and the superior parietal lobule in implementing the function of a frame of reference transformation during imitation. Moreover, the model posits the ventral premotor cortex as performing an inverse computation. The simulations reveal that: i) the transformation system can learn and represent the changes in extrinsic to intrinsic coordinates when an imitator observes a demonstrator; ii) the inverse model of the imitator's frontal mirror neuron system can be trained to provide the motor plans for the imitated actions.

Classical mirror symmetry

CERN Document Server

Jinzenji, Masao

2018-01-01

This book furnishes a brief introduction to classical mirror symmetry, a term that denotes the process of computing Gromov–Witten invariants of a Calabi–Yau threefold by using the Picard–Fuchs differential equation of period integrals of its mirror Calabi–Yau threefold. The book concentrates on the best-known example, the quintic hypersurface in 4-dimensional projective space, and its mirror manifold. First, there is a brief review of the process of discovery of mirror symmetry and the striking result proposed in the celebrated paper by Candelas and his collaborators. Next, some elementary results of complex manifolds and Chern classes needed for study of mirror symmetry are explained. Then the topological sigma models, the A-model and the B-model, are introduced. The classical mirror symmetry hypothesis is explained as the equivalence between the correlation function of the A-model of a quintic hyper-surface and that of the B-model of its mirror manifold. On the B-model side, the process of construct...

Synchronisation of electron-beam controlled CO2 lasers with a plasma mirror

International Nuclear Information System (INIS)

Basov, N.G.; Boiko, V.A.; Danilychev, V.A.; Zvorykin, V.D.; Lobanov, A.N.; Kholin, I.V.; Chugunov, A.Y.

1979-03-01

A new approach to the development of laser systems for spherically symmetrical compression of thermonuclear targets which essentially involves using a plasma formed by the action of laser radiation on the surface of a target as a common mirror for high-power electron-beam-controlled CO 2 lasers distributed uniformly around a sphere has been proposed. The achievement of the required time-synchronised operation of several lasers to obtain symmetrical irradiation is discussed here. It is found that the lasers cannot be synchronised accurately by stabilising only the electrical parameters of the systems. Even if the laser pumping systems are switched on strictly simultaneously, small random fluctuations in the pumping level, active mixture composition, optical Q factor of the resonators and other parameters give rise to an appreciable scatter in the output pulse evolution times. Methods for precise synchronisation based on introducing optical coupling between the laser resonators are proposed. (UK)

Mirror suspension system for the TAMA SAS

International Nuclear Information System (INIS)

Takamori, Akiteru; Ando, Masaki; Bertolini, Alessandro; Cella, Giancarlo; DeSalvo, Riccardo; Fukushima, Mitsuhiro; Iida, Yukiyoshi; Jacquier, Florian; Kawamura, Seiji; Marka, Szabolcs; Nishi, Yuhiko; Numata, Kenji; Sannibale, Virginio; Somiya, Kentaro; Takahashi, Ryutaro; Tariq, Hareem; Tsubono, Kimio; Ugas, Jose; Viboud, Nicolas; Yamamoto, Hiroaki; Yoda, Tatsuo; Wang Chenyang

2002-01-01

Several R and D programmes are ongoing to develop the next generation of interferometric gravitational wave detectors providing the superior sensitivity desired for refined astronomical observations. In order to obtain a wide observation band at low frequencies, the optics need to be isolated from the seismic noise. The TAMA SAS (seismic attenuation system) has been developed within an international collaboration between TAMA, LIGO, and some European institutes, with the main objective of achieving sufficient low-frequency seismic attenuation (-180 dB at 10 HZ). The system suppresses seismic noise well below the other noise levels starting at very low frequencies above 10 Hz. It also includes an active inertial damping system to decrease the residual motion of the optics enough to allow a stable operation of the interferometer. The TAMA SAS also comprises a sophisticated mirror suspension subsystem (SUS). The SUS provides support for the optics and vibration isolation complementing the SAS performance. The SUS is equipped with a totally passive magnetic damper to suppress internal resonances without degrading the thermal noise performance. In this paper we discuss the SUS details and present prototype results

Unbroken Mirror Neurons in Autism Spectrum Disorders

Science.gov (United States)

Fan, Yang-Teng; Decety, Jean; Yang, Chia-Yen; Liu, Ji-Lin; Cheng, Yawei

2010-01-01

Background: The "broken mirror" theory of autism, which proposes that a dysfunction of the human mirror neuron system (MNS) is responsible for the core social and cognitive deficits in individuals with autism spectrum disorders (ASD), has received considerable attention despite weak empirical evidence. Methods: In this electroencephalographic…

Mirror reactor blankets

International Nuclear Information System (INIS)

Lee, J.D.; Barmore, W.L.; Bender, D.J.; Doggett, J.N.; Galloway, T.R.

1976-01-01

The general requirements of a breeding blanket for a mirror reactor are described. The following areas are discussed: (1) facility layout and blanket maintenance, (2) heat transfer and thermal conversion system, (3) materials, (4) tritium containment and removal, and (5) nuclear performance

System design for the new TMX machine

International Nuclear Information System (INIS)

Chargin, A.K.; Calderon, M.O.; Mooney, L.J.; Vogtlin, G.E.

1977-01-01

The Tandem Mirror Experiment (TMX) is designed to test the physics of a new approach to Q-enhancement in open confinement systems. In the tandem mirror concept, the ends of a long solenoid are plugged electrostatically by means of ambipolar potential barriers created in two mirror machines or plugs, one at each end of the solenoid. The ambipolar potential in mirror machines develops as a consequence of the higher scattering rate of electrons and the balancing of electron and ion loss rates. The TMX experiment incorporates very few new engineering developments, but it does involve a new way of combining in an integrated system many previously developed ideas. The engineering task is to design the machine that would provide a proof-of-principle evaluation of the tandem mirror concept as rapidly as possible. The preliminary design was started in September 1976 and was completed by December 1976. It led to a cost estimate of $11 million and a scheduled construction period of 18 months

Plasma impact on diagnostic mirrors in JET

Directory of Open Access Journals (Sweden)

A. Garcia-Carrasco

2017-08-01

Full Text Available Metallic mirrors will be essential components of all optical systems for plasma diagnosis in ITER. This contribution provides a comprehensive account on plasma impact on diagnostic mirrors in JET with the ITER-Like Wall. Specimens from the First Mirror Test and the lithium-beam diagnostic have been studied by spectrophotometry, ion beam analysis and electron microscopy. Test mirrors made of molybdenum were retrieved from the main chamber and the divertor after exposure to the 2013–2014 experimental campaign. In the main chamber, only mirrors located at the entrance of the carrier lost reflectivity (Be deposition, while those located deeper in the carrier were only slightly affected. The performance of mirrors in the JET divertor was strongly degraded by deposition of beryllium, tungsten and other species. Mirrors from the lithium-beam diagnostic have been studied for the first time. Gold coatings were severely damaged by intense arcing. As a consequence, material mixing of the gold layer with the stainless steel substrate occurred. Total reflectivity dropped from over 90% to less than 60%, i.e. to the level typical for stainless steel.

Mirrors design, analysis and manufacturing of the 550mm Korsch telescope experimental model

Science.gov (United States)

Huang, Po-Hsuan; Huang, Yi-Kai; Ling, Jer

2017-08-01

In 2015, NSPO (National Space Organization) began to develop the sub-meter resolution optical remote sensing instrument of the next generation optical remote sensing satellite which follow-on to FORMOSAT-5. Upgraded from the Ritchey-Chrétien Cassegrain telescope optical system of FORMOSAT-5, the experimental optical system of the advanced optical remote sensing instrument was enhanced to an off-axis Korsch telescope optical system which consists of five mirrors. It contains: (1) M1: 550mm diameter aperture primary mirror, (2) M2: secondary mirror, (3) M3: off-axis tertiary mirror, (4) FM1 and FM2: two folding flat mirrors, for purpose of limiting the overall volume, reducing the mass, and providing a long focal length and excellent optical performance. By the end of 2015, we implemented several important techniques including optical system design, opto-mechanical design, FEM and multi-physics analysis and optimization system in order to do a preliminary study and begin to develop and design these large-size lightweight aspheric mirrors and flat mirrors. The lightweight mirror design and opto-mechanical interface design were completed in August 2016. We then manufactured and polished these experimental model mirrors in Taiwan; all five mirrors ware completed as spherical surfaces by the end of 2016. Aspheric figuring, assembling tests and optical alignment verification of these mirrors will be done with a Korsch telescope experimental structure model in 2018.

All solid-state diode pumped Nd:YAG MOPA with stimulated Brillouin phase conjugate mirror

NARCIS (Netherlands)

Offerhaus, Herman L.; Godfried, Herman; Godfried, H.P; Witteman, W.J.

1996-01-01

At the Nederlands Centrum voor Laser Research (NCLR) a 1 kHz diode-pumped Nd:YAG Master Oscillator Power Amplifier (MOPA) chain with a Stimulated Brillouin Scattering (SBS) Phase Conjugate mirror is designed and operated. A small Brewster angle Nd:YAG slab (2 by 2 by 20 mm) is side pumped with 200

Vibratory response of a mirror support/positioning system for the Advanced Photon Source project at Argonne National Laboratory

International Nuclear Information System (INIS)

Basdogan, I.; Shu, Deming; Kuzay, T.M.; Royston, T.J.; Shabana, A.A.

1996-01-01

The vibratory response of a typical mirror support/positioning system used at the experimental station of the Advanced Photon Source (APS) project at Argonne National Laboratory is investigated. Positioning precision and stability are especially critical when the supported mirror directs a high-intensity beam aimed at a distant target. Stability may be compromised by low level, low frequency seismic and facility-originated vibrations traveling through the ground and/or vibrations caused by flow-structure interactions in the mirror cooling system. The example case system has five positioning degrees of freedom through the use of precision actuators and rotary and linear bearings. These linkage devices result in complex, multi-dimensional vibratory behavior that is a function of the range of positioning configurations. A rigorous multibody dynamical approach is used for the development of the system equations. Initial results of the study, including estimates of natural frequencies and mode shapes, as well as limited parametric design studies, are presented. While the results reported here are for a particular system, the developed vibratory analysis approach is applicable to the wide range of high-precision optical positioning systems encountered at the APS and at other comparable facilities

Mirror symmetry

CERN Document Server

Voisin, Claire

1999-01-01

This is the English translation of Professor Voisin's book reflecting the discovery of the mirror symmetry phenomenon. The first chapter is devoted to the geometry of Calabi-Yau manifolds, and the second describes, as motivation, the ideas from quantum field theory that led to the discovery of mirror symmetry. The other chapters deal with more specialized aspects of the subject: the work of Candelas, de la Ossa, Greene, and Parkes, based on the fact that under the mirror symmetry hypothesis, the variation of Hodge structure of a Calabi-Yau threefold determines the Gromov-Witten invariants of its mirror; Batyrev's construction, which exhibits the mirror symmetry phenomenon between hypersurfaces of toric Fano varieties, after a combinatorial classification of the latter; the mathematical construction of the Gromov-Witten potential, and the proof of its crucial property (that it satisfies the WDVV equation), which makes it possible to construct a flat connection underlying a variation of Hodge structure in the ...

Calibration of the ORNL two-dimensional Thomson scattering system

International Nuclear Information System (INIS)

Thomas, C.E. Jr.; Lazarus, E.A.; Kindsfather, R.R.; Murakami, M.; Stewart, K.A.

1985-10-01

A unified presentation of the calibrations needed for accurate calculation of electron temperature and density from Thomson scattering data for the Oak Ridge National Laboratory two-dimensional Thomson scattering system (SCATPAK II) is made. Techniques are described for measuring the range of wavelengths to which each channel is responsive. A statistical method for calibrating the gain of each channel in the system is given, and methods of checking for internal consistency and accuracy are presented. The relationship between the constants describing the relative light collection efficiency of each channel and plasma light-scattering theory is developed, methods for measuring the channel efficiencies and evaluating their accuracy are described, and the effect on these constants of bending fiber optics is discussed. The use of Rayleigh or Raman scattering for absolute efficiency (density) calibration, stray light measurement, and system efficiency evaluation is discussed; the relative merits of Rayleigh vs Raman scattering are presented; and the relationship among the Rayleigh/Raman calibrations, relative channel efficiency constants, and absolute efficiencies is developed

Technology of mirror machines: LLL facilities for magnetic mirror fusion experiments

International Nuclear Information System (INIS)

Batzer, T.H.

1977-01-01

Significant progress in plasma confinement and temperature has been achieved in the 2XIIB facility at Livermore. These encouraging results, and their theoretical corroboration, have provided a firm basis for the design of a new generation of magnetic mirror experiments, adding support to the mirror concept of a fusion reactor. Two new mirror experiments have been proposed to succeed the currently operating 2XIIB facility. The first of these called TMX (Tandem Mirror Experiment) has been approved and is currently under construction. TMX is designed to utilize the intrinsic positive plasma potential of two strong, and relatively small, minimum B mirror cells to enhance the confinement of a much larger, magnetically weaker, centrally-located mirror cell. The second facility, MFTF (Mirror Fusion Test Facility), is currently in preliminary design with line item approval anticipated for FY 78. MFTF is designed primarily to exploit the experimental and theoretical results derived from 2XIIB. Beyond that, MFTF will develop the technology for the transition from the present small mirror experiments to large steady-state devices such as the mirror FERF/FTR. The sheer magnitude of the plasma volume, magnetic field, neutral beam power, and vacuum pumping capacity, particularly in the case of MFTF, has placed new and exciting demands on engineering technology. An engineering overview of MFTF, TMX, and associated MFE activities at Livermore will be presented

Inelastic two composite particle systems scattering at high energy

International Nuclear Information System (INIS)

Zhang Yushun.

1986-11-01

In this paper, by using the collective coordinate of Bohr and phenomenological deformed optical potentials, the scattering amplitudes of two composite particle systems can be obtained and the collective excitation for two composite particle systems in the scattering process is discussed. (author). 10 refs, 6 figs, 2 tabs

Scattering and the Point Spread Function of the New Generation Space Telescope

Science.gov (United States)

Schreur, Julian J.

1996-01-01

Preliminary design work on the New Generation Space Telescope (NGST) is currently under way. This telescope is envisioned as a lightweight, deployable Cassegrain reflector with an aperture of 8 meters, and an effective focal length of 80 meters. It is to be folded into a small-diameter package for launch by an Atlas booster, and unfolded in orbit. The primary is to consist of an octagon with a hole at the center, and with eight segments arranged in a flower petal configuration about the octagon. The comers of the petal-shaped segments are to be trimmed so that the package will fit atop the Atlas booster. This mirror, along with its secondary will focus the light from a point source into an image which is spread from a point by diffraction effects, figure errors, and scattering of light from the surface. The distribution of light in the image of a point source is called a point spread function (PSF). The obstruction of the incident light by the secondary mirror and its support structure, the trimmed corners of the petals, and the grooves between the segments all cause the diffraction pattern characterizing an ideal point spread function to be changed, with the trimmed comers causing the rings of the Airy pattern to become broken up, and the linear grooves causing diffraction spikes running radially away from the central spot, or Airy disk. Any figure errors the mirror segments may have, or any errors in aligning the petals with the central octagon will also spread the light out from the ideal point spread function. A point spread function for a mirror the size of the NGST and having an incident wavelength of 900 nm is considered. Most of the light is confined in a circle with a diameter of 0.05 arc seconds. The ring pattern ranges in intensity from 10(exp -2) near the center to 10(exp -6) near the edge of the plotted field, and can be clearly discerned in a log plot of the intensity. The total fraction of the light scattered from this point spread function is called

From music making to speaking: Engaging the mirror neuron system in autism

OpenAIRE

Wan, Catherine Y.; Demaine, Krystal; Zipse, Lauryn; Norton, Andrea; Schlaug, Gottfried

2010-01-01

Individuals with autism show impairments in emotional tuning, social interactions and communication. These are functions that have been attributed to the putative human mirror neuron system (MNS), which contains neurons that respond to the actions of self and others. It has been proposed that a dysfunction of that system underlies some of the characteristics of autism. Here, we review behavioral and imaging studies that implicate the MNS (or a brain network with similar functions) in sensory-...

Imitation and Action Understanding in Autistic Spectrum Disorders: How Valid Is the Hypothesis of a Deficit in the Mirror Neuron System?

Science.gov (United States)

Hamilton, Antonia F. de C.; Brindley, Rachel M.; Frith, Uta

2007-01-01

The motor mirror neuron system supports imitation and goal understanding in typical adults. Recently, it has been proposed that a deficit in this mirror neuron system might contribute to poor imitation performance in children with autistic spectrum disorders (ASD) and might be a cause of poor social abilities in these children. We aimed to test…

Learning of Spatial Relationships between Observed and Imitated Actions allows Invariant Inverse Computation in the Frontal Mirror Neuron System

Science.gov (United States)

Oh, Hyuk; Gentili, Rodolphe J.; Reggia, James A.; Contreras-Vidal, José L.

2014-01-01

It has been suggested that the human mirror neuron system can facilitate learning by imitation through coupling of observation and action execution. During imitation of observed actions, the functional relationship between and within the inferior frontal cortex, the posterior parietal cortex, and the superior temporal sulcus can be modeled within the internal model framework. The proposed biologically plausible mirror neuron system model extends currently available models by explicitly modeling the intraparietal sulcus and the superior parietal lobule in implementing the function of a frame of reference transformation during imitation. Moreover, the model posits the ventral premotor cortex as performing an inverse computation. The simulations reveal that: i) the transformation system can learn and represent the changes in extrinsic to intrinsic coordinates when an imitator observes a demonstrator; ii) the inverse model of the imitator’s frontal mirror neuron system can be trained to provide the motor plans for the imitated actions. PMID:22255261

Mirror neurons: Enigma of the metaphysical modular brain.

Science.gov (United States)

Acharya, Sourya; Shukla, Samarth

2012-07-01

Mirror neurons are one of the most important discoveries in the last decade of neuroscience. These are a variety of visuospatial neurons which indicate fundamentally about human social interaction. Essentially, mirror neurons respond to actions that we observe in others. The interesting part is that mirror neurons fire in the same way when we actually recreate that action ourselves. Apart from imitation, they are responsible for myriad of other sophisticated human behavior and thought processes. Defects in the mirror neuron system are being linked to disorders like autism. This review is a brief introduction to the neurons that shaped our civilization.

Polarization and reflectivity changes on mirror based viewing systems during long pulse operation

Energy Technology Data Exchange (ETDEWEB)

Malaquias, A. [Association-Euratom/IST, Instituto Superior Tecnico, Lisboa (Portugal); Von Hellermann, M. [Association-Euratom-FOM, Institute for Plasma Physique Rijnhuizen (Netherlands); Lotte, P. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Tugarinov, S. [SRC Triniti, Troitsk (Russian Federation); Voitsenya, V.S. [Institute of Plasma Physics of the National Science Center, Kharkov Institute of Physics and Technology (Ukraine)

2003-07-01

In ITER, long plasma discharges will produce a high flux of energetic particles leading to high erosion rate, as a consequence materials from first wall and divertor i.e. Be and C (or eventually W) will be released and will pile up on slightly-buried surfaces. Particularly affected by this scenario are MSE (motional Stark effect) diagnostic first mirrors. In this work the change in the polarization state of incident light induced by Be and C deposition on Au mirror is calculated. The results show that Be and C deposition on Au mirror will induce changes on light polarization and reflectivity properties as a function of layer thickness. For Be case, all the induced effects are seem to stabilize above 75 nm. This result indicates that the otherwise Au mirror becomes a Be mirror suggesting that the use of Be mirror as first mirror may help to diminish the transitional optical changes from Au to Be. For the case of C deposit, the results show that the polarization induced changes and intensity modulation (interference) are quite marked and much more visible than in the case of Be. In that sense, machines using C components will produce a more undesirable mirror deposit than a BPX with a Be first wall, although, they take advantage of a lower deposition rate. We have no data on Be or C deposition rate for ITER yet, but for the ITER MSE case, control and monitoring of the mirror state shall be included in the optical design. Uncertainties on measuring the polarization angle can be translated on the achievable spatial resolution.

Polarization and reflectivity changes on mirror based viewing systems during long pulse operation

International Nuclear Information System (INIS)

Malaquias, A.; Von Hellermann, M.; Lotte, P.; Voitsenya, V.S.

2003-01-01

In ITER, long plasma discharges will produce a high flux of energetic particles leading to high erosion rate, as a consequence materials from first wall and divertor i.e. Be and C (or eventually W) will be released and will pile up on slightly-buried surfaces. Particularly affected by this scenario are MSE (motional Stark effect) diagnostic first mirrors. In this work the change in the polarization state of incident light induced by Be and C deposition on Au mirror is calculated. The results show that Be and C deposition on Au mirror will induce changes on light polarization and reflectivity properties as a function of layer thickness. For Be case, all the induced effects are seem to stabilize above 75 nm. This result indicates that the otherwise Au mirror becomes a Be mirror suggesting that the use of Be mirror as first mirror may help to diminish the transitional optical changes from Au to Be. For the case of C deposit, the results show that the polarization induced changes and intensity modulation (interference) are quite marked and much more visible than in the case of Be. In that sense, machines using C components will produce a more undesirable mirror deposit than a BPX with a Be first wall, although, they take advantage of a lower deposition rate. We have no data on Be or C deposition rate for ITER yet, but for the ITER MSE case, control and monitoring of the mirror state shall be included in the optical design. Uncertainties on measuring the polarization angle can be translated on the achievable spatial resolution

Mirroring Facial Expressions and Emotions in Dyadic Conversations

DEFF Research Database (Denmark)

Navarretta, Costanza

2016-01-01

This paper presents an investigation of mirroring facial expressions and the emotions which they convey in dyadic naturally occurring first encounters. Mirroring facial expressions are a common phenomenon in face-to-face interactions, and they are due to the mirror neuron system which has been...... and overlapping facial expressions are very frequent. In this study, we want to determine whether the overlapping facial expressions are mirrored or are otherwise correlated in the encounters, and to what extent mirroring facial expressions convey the same emotion. The results of our study show that the majority...... of smiles and laughs, and one fifth of the occurrences of raised eyebrows are mirrored in the data. Moreover some facial traits in co-occurring expressions co-occur more often than it would be expected by chance. Finally, amusement, and to a lesser extent friendliness, are often emotions shared by both...

Advances in the FTU collective Thomson scattering system

Energy Technology Data Exchange (ETDEWEB)

Bin, W., E-mail: wbin@ifp.cnr.it; Bruschi, A.; Grosso, G.; Alessi, E.; De Angeli, M.; Figini, L.; Garavaglia, S.; Granucci, G.; Lontano, M.; Mellera, V.; Minelli, D.; Moro, A.; Muraro, A.; Nardone, A.; Simonetto, A.; Tartari, U. [Istituto di Fisica del Plasma “P. Caldirola,” Consiglio Nazionale delle Ricerche, Milano (Italy); D’Arcangelo, O.; Castaldo, C.; Centioli, C.; Magagnino, S. [ENEA for EUROfusion, Frascati (Italy); and others

2016-11-15

The new collective Thomson scattering diagnostic installed on the Frascati Tokamak Upgrade device started its first operations in 2014. The ongoing experiments investigate the presence of signals synchronous with rotating tearing mode islands, possibly due to parametric decay processes, and phenomena affecting electron cyclotron beam absorption or scattering measurements. The radiometric system, diagnostic layout, and data acquisition system were improved accordingly. The present status and near-term developments of the diagnostic are presented.

The magnet power control system for the tandem mirror experiment-upgrade

International Nuclear Information System (INIS)

Bell, H.H.

1983-01-01

This paper describes the desktop computer/CAMAC based system that controls the power source for the Tandem Mirror Experiment-Upgrade (TMX-U) magnet power system. Presently it contains 42 dc rectifier power supplies connected to 24 magnet coils arranged in 17 circuits. During each shot, the system delivers 22.6 MW dc to the magnets for about 3 s. The system is presently being changed to add six power supplies, two solenoidal throttle coils, and two reverse C-coils. When complete, the delivered power will increase to 36.9 MW. The closed-loop control system usually provides current (and thus, magnetic field) that is within 1% of the requested current. Achieving this accuracy required using grounding, shielding, and isolation methods to reduce noise and related problems

Paraboloidal X-ray telescope mirror for solar coronal spectroscopy

Science.gov (United States)

Brown, W. A.; Bruner, E. C., Jr.; Acton, L. W.; Franks, A.; Stedman, M.; Speer, R. J.

1979-01-01

The telescope mirror for the X-ray Spectrograph Spectrometer Telescope System is a sixty degree sector of an extreme off-axis paraboloid of revolution. It was designed to focus a coronal region 1 by 10 arc seconds in size on the entrance slit of the spectrometer after reflection from the gold surface. This paper discusses the design, manufacture, and metrology of the mirror, the methods of precision mechanical metrology used to focus the system, and the mounting system which locates the mirror and has proven itself through vibration tests. In addition, the results of reflection efficiency measurements, alignment tolerances, and ray trace analysis of the effects of misalignment are considered.

Near specular scatter analysis method with a new goniophotometer

Science.gov (United States)

Meyen, Stephanie; Sutter, Florian; Heller, Peter

2014-09-01

The challenge of improving component quality and reducing cost has focused the attention of the solar thermal power industry on reliable component characterization methods. Since the reflector plays a key role in the energy conversion chain, the analysis of its reflectance properties has become a lively discussed issue in recent years. State of the art measurement instruments for specular reflectance do not give satisfying results, because they do not resolve sufficiently the near specular scatter of possible low cost mirror material candidates. The measurement of the BRDF offers a better solution than the traditional approach of placing a detector in the specular reflected beam path. However, due to the requirement of high angular resolution in the range of 1 mrad (0.057°) or better and the challenge of measuring high dynamic differences between the specular peak and the scatter signal, typical commercial scanning goniophotometers capable of this are rare. These instruments also face the disadvantages of impractically long acquisition times and, to reach the high angular resolution, occupy a large space (several meters side length). We have taken on the appealing idea of a parallel imaging goniophotometer and designed a prototype based on this principle. A mirrored ellipsoid is used to redirect the reflected light coming from a sample towards a camera with a fisheye lens. This way the complete light distribution is captured simultaneously. A key feature allows the distinction of the high intensity specular peak and the low intensity scatter. In this article we explain the prototype design and demonstrate its functionality based on comparison measurements done with a commercial scanning goniophotometer. We identify limitations related in part to the concept and in part to the specific prototype and suggest improvements. Finally we conclude that the concept is well suitable for the analysis of near specular scatter of mirror materials, although less adequate for

Smart Makeup Mirror: Computer Augmented Mirror to Aid Makeup Application

OpenAIRE

岩渕, 絵里子; 椎尾, 一郎

2008-01-01

In this paper, we present the system that aids people in wearing makeup easily and make the process enjoyable. The proposed system is the Smart Makeup Mirror device, which is an electronic dressing table that facilitates the process of makeup application. In this system, we place a high-resolution camera on top of a computer display. We developed some functions such as Automatic zoom to a specific part of the face, Display our face from various angles , and Simulation of the lighting conditio...

Laser beam-forming by deformable mirror for laser isotope separation

International Nuclear Information System (INIS)

Nemoto, Koshichi; Fujii, Takashi; Goto, Naohiko

1995-01-01

A rectangular laser beam of uniform intensity is very suitable for laser isotope separation. In this paper, we propose a beam-forming system which consists two deformable mirrors. One of the mirrors changes the beam intensity and the other compensates for phase distortion. We developed a deformable mirror for beam-forming. Its deformed surface is similar to the ideal mirror surface for beam-forming. We reshaped a Gaussian-like He-Ne laser beam into a beam with a more uniform intensity profile by a simple deformable mirror. (author)

Quasi-Three Body Systems: Properties and Scattering

International Nuclear Information System (INIS)

Amusia, M. Ya.

2017-01-01

We investigate systems of three mutually interacting particles with masses m e , m μ , M that obey the following inequality m e ≪ m μ ≪ M. Then the three-body problem reduces to the two-body scattering or structure of m e in the field of the pseudo-nucleus m μ M. We calculate analytically the properties of considered systems, such as the scattering cross-sections, hyperfine splitting, Auger decay of exited states and Lamb shifts, presenting them as expansions in powers of the parameter β=m e /m μ ≪1. (author)

Mirror neuron framework yields representations for robot interaction

NARCIS (Netherlands)

Barakova, E.I.; Lourens, T.

2009-01-01

Common coding is a functional principle that underlies the mirror neuron paradigm. It insures actual parity between perception and action, since the perceived and performed actions are equivalently and simultaneously represented within the mirror neuron system. Based on the parity of this

Fabrication of high precision metallic freeform mirrors with magnetorheological finishing (MRF)

Science.gov (United States)

Beier, Matthias; Scheiding, Sebastian; Gebhardt, Andreas; Loose, Roman; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas

2013-09-01

The fabrication of complex shaped metal mirrors for optical imaging is a classical application area of diamond machining techniques. Aspherical and freeform shaped optical components up to several 100 mm in diameter can be manufactured with high precision in an acceptable amount of time. However, applications are naturally limited to the infrared spectral region due to scatter losses for shorter wavelengths as a result of the remaining periodic diamond turning structure. Achieving diffraction limited performance in the visible spectrum demands for the application of additional polishing steps. Magnetorheological Finishing (MRF) is a powerful tool to improve figure and finish of complex shaped optics at the same time in a single processing step. The application of MRF as a figuring tool for precise metal mirrors is a nontrivial task since the technology was primarily developed for figuring and finishing a variety of other optical materials, such as glasses or glass ceramics. In the presented work, MRF is used as a figuring tool for diamond turned aluminum lightweight mirrors with electroless nickel plating. It is applied as a direct follow-up process after diamond machining of the mirrors. A high precision measurement setup, composed of an interferometer and an advanced Computer Generated Hologram with additional alignment features, allows for precise metrology of the freeform shaped optics in short measuring cycles. Shape deviations less than 150 nm PV / 20 nm rms are achieved reliably for freeform mirrors with apertures of more than 300 mm. Characterization of removable and induced spatial frequencies is carried out by investigating the Power Spectral Density.

The simultaneous measurement of energy and linear polarization of the scattered radiation in resonant inelastic soft x-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Braicovich, L., E-mail: lucio.braicovich@polimi.it; Minola, M.; Dellea, G.; Ghiringhelli, G. [CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo Da Vinci 32, Milano I-20133 (Italy); Le Tacon, M. [Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Moretti Sala, M.; Morawe, C.; Peffen, J.-Ch.; Yakhou, F.; Brookes, N. B. [European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble F-38043 (France); Supruangnet, R. [Synchrotron Light Research Institute, Nakhon Ratchasima (Thailand)

2014-11-15

Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution soft-RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B{sub 4}C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF (European Synchrotron Radiation Facility); it has been fully characterized and it has been used for a demonstration experiment at the Cu L{sub 3} edge on a high-T{sub c} superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%.

New Reflections on Mirror Neuron Research, the Tower of Babel, and Intercultural Education

Science.gov (United States)

Westbrook, Timothy Paul

2015-01-01

Studies of the human mirror neuron system demonstrate how mental mimicking of one's social environment affects learning. The mirror neuron system also has implications for intercultural encounters. This article explores the common ground between the mirror neuron system and theological principles from the Tower of Babel narrative and applies them…

Mirror Station for studies of the protection of diagnostic mirrors from impurity contamination in ITER: Design and first results

International Nuclear Information System (INIS)

Litnovsky, Andrey; Krasikov, Yuri; Kotov, Vladislav; Matveeva, Maria; Panin, Anatoly; Vera, Liliana; Buzi, Luxherta; Neubauer, Olaf; Biel, Wolfgang; Nicolai, Dirk; Mertens, Philippe; Linsmeier, Christian

2015-01-01

Highlights: • Paper is devoted to protection of diagnostic mirrors for ITER. • Modeling predicts suppression of impurity deposition on mirrors by using ducts. • The mirror tube system (Mirror Station) was built to validate the model. • The Mirror Station was exposed in TEXTOR. • The decrease of deposition in cylindrical ducts with fins cannot be confirmed. • All mirrors located in conical ducts preserved their reflectivity. - Abstract: Optical and laser-based diagnostics in ITER will use mirrors to transmit plasma radiation and laser light to the corresponding detectors and cameras. Mirrors will be sputtered by the fast plasma particles and contaminated by impurities leading to the degradation of the reflectivity and hampering the performance of corresponding diagnostics. Dedicated measures were proposed to minimize the impurity deposition comprising the use of shutters and fins inside diagnostic ducts to trap impurities on their way toward the mirror located in the end of these ducts. Modeling results predict at least 7-fold suppression of the deposition for the duct having four fins located at the distance of a half of a diameter from each other. The Mirror Station (MS) was designed to validate modeling predictions and to study the suppression of deposition inside of diagnostic ducts. The MS contained cylindrical and cone-shaped tubes of different lengths with smooth and shaped geometry of ducts. The MS was exposed in the midplane port of TEXTOR for about 3960 s of plasma operation. After exposure, no drastic suppression of deposition was observed in the cylindrical ducts with fins. In the conical tubes no deposition was detected outlining the advantages of a cone form.

Avoiding unstable regions in the design space of EUV mirror systems comprising high-order aspheric surfaces

NARCIS (Netherlands)

Marinescu, O.; Bociort, F.; Braat, J.

2004-01-01

When Extreme Ultraviolet mirror systems having several high-order aspheric surfaces are optimized, the configurations often enter into highly unstable regions of the parameter space. Small changes of system parameters lead then to large changes in ray paths, and therefore optimization algorithms

Mirrors for synchrotron-radiation beamlines

International Nuclear Information System (INIS)

Howells, M.R.

1993-09-01

The authors consider the role of mirrors in synchrotron-radiation beamlines and discuss the optical considerations involved in their design. They discuss toroidal, spherical, elliptical, and paraboloidal mirrors in detail with particular attention to their aberration properties. They give a treatment of the sine condition and describe its role in correcting the coma of axisymmetric systems. They show in detail how coma is inevitable in single-reflection, grazing-incidence systems but correctable in two-reflection systems such as those of the Wolter type. In an appendix, they give the theory of point aberrations of reflectors of a general shape and discuss the question of correct naming of aberrations. In particular, a strict definition of coma is required if attempts at correction are to be based on the sine condition

Language comprehension warps the mirror neuron system.

Science.gov (United States)

Zarr, Noah; Ferguson, Ryan; Glenberg, Arthur M

2013-01-01

Is the mirror neuron system (MNS) used in language understanding? According to embodied accounts of language comprehension, understanding sentences describing actions makes use of neural mechanisms of action control, including the MNS. Consequently, repeatedly comprehending sentences describing similar actions should induce adaptation of the MNS thereby warping its use in other cognitive processes such as action recognition and prediction. To test this prediction, participants read blocks of multiple sentences where each sentence in the block described transfer of objects in a direction away or toward the reader. Following each block, adaptation was measured by having participants predict the end-point of videotaped actions. The adapting sentences disrupted prediction of actions in the same direction, but (a) only for videos of biological motion, and (b) only when the effector implied by the language (e.g., the hand) matched the videos. These findings are signatures of the MNS.

Mirror and (absence of) counter-mirror responses to action sounds measured with TMS.

Science.gov (United States)

Ticini, Luca F; Schütz-Bosbach, Simone; Waszak, Florian

2017-11-01

To what extent is the mirror neuron mechanism malleable to experience? The answer to this question can help characterising its ontogeny and its role in social cognition. Some suggest that it develops through sensorimotor associations congruent with our own actions. Others argue for its extreme volatility that will encode any sensorimotor association in the environment. Here, we added to this debate by exploring the effects of short goal-directed 'mirror' and 'counter-mirror' trainings (a 'mirror' training is defined as the first type of training encountered by the participants) on human auditory mirror motor-evoked potentials (MEPs). We recorded MEPs in response to two tones void of previous motor meaning, before and after mirror and counter-mirror trainings in which participants generated two tones of different pitch by performing free-choice button presses. The results showed that mirror MEPs, once established, were protected against an equivalent counter-mirror experience: they became manifest very rapidly and the same number of training trials that lead to the initial association did not suffice to reverse the MEP pattern. This steadiness of the association argues that, by serving direct-matching purposes, the mirror mechanism is a good solution for social cognition. © The Author (2017). Published by Oxford University Press.

Axisymmetric magnetic mirrors for plasma confinement. Recent development and perspectives

International Nuclear Information System (INIS)

Kruglyakov, E.P.; Dimov, G.I.; Ivanov, A.A.; Koidan, V.S.

2003-01-01

Mirrors are the only one class of fusion systems which completely differs topologically from the systems with closed magnetic configurations. At present, three modern types of different mirror machines for plasma confinement and heating exist in Novosibirsk (Gas Dynamic Trap,- GDT, Multi-mirror,- GOL-3, and Tandem Mirror,- AMBAL-M). All these systems are attractive from the engineering point of view because of very simple axisymmetric geometry of magnetic configurations. In the present paper, the status of different confinement systems is presented. The experiments most crucial for the mirror concept are described such as a demonstration of different principles of suppression of electron heat conductivity (GDT, GOL-3), finding of MHD stable regimes of plasma confinement in axisymmetric geometry of magnetic field (GDT, AMBAL-M), an effective heating of a dense plasma by relativistic electron beam (GOL-3), observation of radial diffusion of quiescent plasma with practically classical diffusion coefficient (AMBAL-M), etc. It should be mentioned that on the basis of the GDT it is possible to make a very important intermediate step. Using 'warm' plasma and oblique injection of fast atoms of D and T one can create a powerful 14 MeV neutron source with a moderate irradiation area (about 1 square meter) and, accordingly, with low tritium consumption. The main plasma parameters achieved are presented and the future perspectives of different mirror machines are outlined. (author)

Autism and the mirror neuron system: Insights from learning and teaching

OpenAIRE

Vivanti, G; Rogers, SJ

2014-01-01

Individuals with autism have difficulties in social learning domains which typically involve mirror neuron system (MNS) activation. However, the precise role of the MNS in the development of autism and its relevance to treatment remain unclear. In this paper, we argue that three distinct aspects of social learning are critical for advancing knowledge in this area: (i) the mechanisms that allow for the implicit mapping of and learning from others' behaviour, (ii) the motivation to attend to an...

Gamma-ray scatter methods applied to industrial measurement systems

Energy Technology Data Exchange (ETDEWEB)

Holstad, Marie Bueie

2004-09-01

Throughout the work presented in this dissertation it has been confirmed that the use of scattered gamma-radiation is a complex but useful tool in industrial measurement science. Scattered radiation has shown to be useful both when traditional measurement principles cannot be used (Chapter 4) and when more information about a system is needed than what is obtained with transmission measurements (Chapter 6). All three main projects (Chapters 4, 5 and 6) confirm that the sensitivity and accuracy of systems based on scattered gamma-radiation depends strongly on the geometry of the setup and that that presence of multiple scattered radiation makes the problems complex. Chapter 4 shows that multiple scattered gamma-radiation can be used for detection of changes in density where the dimensions are too large to use transmitted radiation. There is, however, an upper limit on the thickness of the absorbing medium also when scattered radiation is utilized. As seen in Chapter 5, multiple scattered gamma-radiation can in principle also be used in level gauges with very compact measurement geometries. The main challenges are the sensitivity to interfaces between materials with similar densities and low count rate. These challenges could not be overcome for level measurements in gravitational separator tanks. The results presented in Chapter 6 show that it is feasible to combine transmission and scatter measurements to characterize produced water in the oil and gas industry. (Author)

Development of multiple scattering lidar to retrieve cloud extinction and size information

International Nuclear Information System (INIS)

Kim, Dukhyeon; Cheong, Hai Du; Kim, Young Gi; Park, Sun Ho

2008-01-01

Traditional Mie scattering cloud lidar have some limitations because of multiple scattering effects. Because this multiple scattering effects induce depolarization of spherical particle and enhancement of extinction coefficient. We cannot measure the phase of water with depolarization lidar, and also cannot measure the extinction coefficient with single FOV(Field Of View)Mie cloud lidar system. In the study, we have developed a multiple field of view Mie cloud liar system which can give many information about the cloud droplet such as cloud effective size, cloud number density, extinction coefficient of cloud, and phase of water through the correction of multiple scattering effects. For this purpose, we have developed a multiple field of view lidar system which composed of 32 different pinholes. Figure 1 shows the schematic diagram and picture of pinholes which start from 100μm to 8mm. Pihole is located at the focal plane of the parabolic mirror, in this case the minimum FOV is 67μrad, maximum FOV is 5.3 mrad. Figure 2 shows Monte Carlo simulation of the multiple scattering photons vs. cloud depth. In this calculation we assumed that wavelength normalized aerosol size(x)is 100, and density of cloud (extinction efficiency)is 0.01m"-1". By measuring FOV dependent signals and aerosol extinction coefficient we can extract effective droplet size through following equations. Here θ"d"is aerosol effective size, and z"j", f, Θ(z)are height, aerosol density dependent function, and angular size of lidar signal at the height z. Finally. f(z)depends on the light mean free path and number of scattering

Rise to SUMMIT: the Sydney University Multiple-Mirror Telescope

Science.gov (United States)

Moore, Anna M.; Davis, John

2000-07-01

The Sydney University Multiple Mirror Telescope (SUMMIT) is a medium-sized telescope designed specifically for high resolution stellar spectroscopy. Throughout the design emphasis has been placed on high efficiency at low cost. The telescope consists of four 0.46 m diameter mirrors mounted on a single welded steel frame. Specially designed mirror cells support and point each mirror, allowing accurate positioning of the images on optical fibers located at the foci of the mirrors. Four fibers convey the light to the future location of a high resolution spectrograph away from the telescope in a stable environment. An overview of the commissioning of the telescope is presented, including the guidance and automatic mirror alignment and focussing systems. SUMMIT is located alongside the Sydney University Stellar Interferometer at the Paul Wild Observatory, near Narrabri, Northern New South Wales.

Multilayer X-ray mirrors for formation of sub-nanometer wavelength range beams

International Nuclear Information System (INIS)

Akhsakhalyan, A.A.; Akhsakhalyan, A.D.; Klyuenkov, E.B.; Murav'ev, V.A.; Salashchenko, N.N.; Kharitonov, A.I.

2005-01-01

Paper reviews the efforts undertaken in the RF Academy of Sciences IPM within recent 5 years to design multilayer mirror systems to produce X-ray wavelength subnanometer range beams. Paper describes a process to fabricate the mentioned systems covering the procedures to obtain supersmooth surfaces of the specified shape, to deposit gradient multilayer structures on the mentioned surfaces and describes the rules to calculate the optimal parameters of mirrors. Paper presents characteristics of mirror system two types: a mirror in the shape of a parabolic cylinder to collimate radiation in the DRON-4, DRON-6 production-type X-ray diffractometers and in the shape of a quadraelliptic reflector - a new wide-aperture four-corner focusing system [ru

Gated integrator PXI-DAQ system for Thomson scattering diagnostics

Energy Technology Data Exchange (ETDEWEB)

Patel, Kiran, E-mail: kkpatel@ipr.res.in; Pillai, Vishal; Singh, Neha; Thomas, Jinto; Kumar, Ajai

2017-06-15

Gated Integrator (GI) PXI based data acquisition (DAQ) system has been designed and developed for the ease of acquiring fast Thomson Scattered signals (∼50 ns pulse width). The DAQ system consists of in-house designed and developed GI modules and PXI-1405 chassis with several PXI-DAQ modules. The performance of the developed system has been validated during the SST-1 campaigns. The dynamic range of the GI module depends on the integrating capacitor (C{sub i}) and the modules have been calibrated using 12 pF and 27 pF integrating capacitors. The developed GI module based data acquisition system consists of sixty four channels for simultaneous sampling using eight PXI based digitization modules having eight channels per module. The error estimation and functional tests of this unit are carried out using standard source and also with the fast detectors used for Thomson scattering diagnostics. User friendly Graphical User Interface (GUI) has been developed using LabVIEW on Windows platform to control and acquire the Thomson scattering signal. A robust, easy to operate and maintain with low power consumption, having higher dynamic range with very good sensitivity and cost effective DAQ system is developed and tested for the SST-1 Thomson scattering diagnostics.

Advanced Thomson scattering system for high-flux linear plasma generator

NARCIS (Netherlands)

Meiden, van der H.J.; Lof, A.R.; Berg, van den M.A.; Brons, S.; Donné, A.J.H.; Eck, van H.J.N.; Koelman, Peter; Koppers, W.R.; Kruijt, O.G.; Naumenko, N.N.; Oyevaar, T.; Prins, P.R.; Rapp, J.; Scholten, J.; Schram, D.C.; Smeets, P.H.M.; Star, van der G.; Tugarinov, S.N.; Zeijlmans van Emmichoven, P.A.

2012-01-01

An advanced Thomson scattering system has been built for a linear plasma generator for plasma surface interaction studies. The Thomson scattering system is based on a Nd:YAG laser operating at the second harmonic and a detection branch featuring a high etendue (f /3) transmission grating

Mirroring the videos of Anonymous:cloud activism, living networks, and political mimesis

OpenAIRE

Fish, Adam Richard

2016-01-01

Mirrors describe the multiplication of data across a network. In this article, I examine the politics of mirroring as practiced on videos by the hacktivist network Anonymous. Mirrors are designed to retain visibility on social media platforms and motivate viewers towards activism. They emerge from a particular social structure and propagate a specific symbolic system. Furthermore, mirrors are not exact replicas nor postmodern representations. Rather, mirroring maps a contestation over visibil...

MSFC Test Results for Selected Mirrors: Brush-Wellman/Goodrich 0.5 meter Joined-Beryllium Mirror; IABG 0.5 meter C/SiC Mirror; Xinetics 0.5 meter SiC Mirror; and Kodak 0.23 meter SiO2 Mirror

Science.gov (United States)

Hadaway, James; Blackwell, Lisa; Matthews, Gary; Eng, Ron; Stahl, Phil; Hraba, John; Thornton, Gary

2002-01-01

The results of cryo tests performed at the XRCF on the above mirrors will be presented. Each mirror was tested from room-temperature to around 30 K. The first three were tested together on a 3-mirror stand in the large chamber using the PhaseCam interferometer, while the Kodak mirror was tested in the small chamber using the EPI interferometer.

Tactile interactions activate mirror system regions in the human brain.

Science.gov (United States)

McKyton, Ayelet

2011-12-07

Communicating with others is essential for the development of a society. Although types of communications, such as language and visual gestures, were thoroughly investigated in the past, little research has been done to investigate interactions through touch. To study this we used functional magnetic resonance imaging. Twelve participants were scanned with their eyes covered while stroking four kinds of items, representing different somatosensory stimuli: a human hand, a realistic rubber hand, an object, and a simple texture. Although the human and the rubber hands had the same overall shape, in three regions there was significantly more blood oxygen level dependent activation when touching the real hand: the anterior medial prefrontal cortex, the ventral premotor cortex, and the posterior superior temporal cortex. The last two regions are part of the mirror network and are known to be activated through visual interactions such as gestures. Interestingly, in this study, these areas were activated through a somatosensory interaction. A control experiment was performed to eliminate confounds of temperature, texture, and imagery, suggesting that the activation in these areas was correlated with the touch of a human hand. These results reveal the neuronal network working behind human tactile interactions, and highlight the participation of the mirror system in such functions.

Mirror neurons, birdsong and human language: a hypothesis

OpenAIRE

Florence eLevy

2012-01-01

AbstractThe Mirror System Hypothesis (MSH) and investigations of birdsong are reviewed in relation to the significance for the development of human symbolic and language capacity, in terms of three fundamental forms of cognitive reference: iconic, indexical, and symbolic. Mirror systems are initially iconic but can progress to indexal reference when produced without the need for concurrent stimuli. Developmental stages in birdsong are also explored with reference to juvenile subsong vs comple...

Volumetric display using a roof mirror grid array

Science.gov (United States)

Miyazaki, Daisuke; Hirano, Noboru; Maeda, Yuuki; Ohno, Keisuke; Maekawa, Satoshi

2010-02-01

A volumetric display system using a roof mirror grid array (RMGA) is proposed. The RMGA consists of a two-dimensional array of dihedral corner reflectors and forms a real image at a plane-symmetric position. A two-dimensional image formed with a RMGA is moved at thigh speed by a mirror scanner. Cross-sectional images of a three-dimensional object are displayed in accordance with the position of the image plane. A volumetric image can be observed as a stack of the cross-sectional images by high-speed scanning. Image formation by a RMGA is free from aberrations. Moreover, a compact optical system can be constructed because a RMGA doesn't have a focal length. An experimental volumetric display system using a galvanometer mirror and a digital micromirror device was constructed. The formation of a three-dimensional image consisting of 1024 × 768 × 400 voxels is confirmed by the experimental system.

The Axisymmetric Tandem Mirror: A Magnetic Mirror Concept Game Changer Magnet Mirror Status Study Group

International Nuclear Information System (INIS)

Simonen, T.; Cohen, R.; Correll, D.; Fowler, K.; Post, D.; Berk, H.; Horton, W.; Hooper, E.B.; Fisch, N.; Hassam, A.; Baldwin, D.; Pearlstein, D.; Logan, G.; Turner, B.; Moir, R.; Molvik, A.; Ryutov, D.; Ivanov, A.A; Kesner, J.; Cohen, B.; McLean, H.; Tamano, T.; Tang, X.Z.; Imai, T.

2008-01-01

Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT

The Axisymmetric Tandem Mirror: A Magnetic Mirror Concept Game Changer Magnet Mirror Status Study Group

Energy Technology Data Exchange (ETDEWEB)

Simonen, T; Cohen, R; Correll, D; Fowler, K; Post, D; Berk, H; Horton, W; Hooper, E B; Fisch, N; Hassam, A; Baldwin, D; Pearlstein, D; Logan, G; Turner, B; Moir, R; Molvik, A; Ryutov, D; Ivanov, A A; Kesner, J; Cohen, B; McLean, H; Tamano, T; Tang, X Z; Imai, T

2008-10-24

Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT

High-resolution and super stacking of time-reversal mirrors in locating seismic sources

KAUST Repository

Cao, Weiping

2011-07-08

Time reversal mirrors can be used to backpropagate and refocus incident wavefields to their actual source location, with the subsequent benefits of imaging with high-resolution and super-stacking properties. These benefits of time reversal mirrors have been previously verified with computer simulations and laboratory experiments but not with exploration-scale seismic data. We now demonstrate the high-resolution and the super-stacking properties in locating seismic sources with field seismic data that include multiple scattering. Tests on both synthetic data and field data show that a time reversal mirror has the potential to exceed the Rayleigh resolution limit by factors of 4 or more. Results also show that a time reversal mirror has a significant resilience to strong Gaussian noise and that accurate imaging of source locations from passive seismic data can be accomplished with traces having signal-to-noise ratios as low as 0.001. Synthetic tests also demonstrate that time reversal mirrors can sometimes enhance the signal by a factor proportional to the square root of the product of the number of traces, denoted as N and the number of events in the traces. This enhancement property is denoted as super-stacking and greatly exceeds the classical signal-to-noise enhancement factor of. High-resolution and super-stacking are properties also enjoyed by seismic interferometry and reverse-time migration with the exact velocity model. © 2011 European Association of Geoscientists & Engineers.

Robust adaptive optics systems for vision science

Science.gov (United States)

Burns, S. A.; de Castro, A.; Sawides, L.; Luo, T.; Sapoznik, K.

2018-02-01

Adaptive Optics (AO) is of growing importance for understanding the impact of retinal and systemic diseases on the retina. While AO retinal imaging in healthy eyes is now routine, AO imaging in older eyes and eyes with optical changes to the anterior eye can be difficult and requires a control and an imaging system that is resilient when there is scattering and occlusion from the cornea and lens, as well as in the presence of irregular and small pupils. Our AO retinal imaging system combines evaluation of local image quality of the pupil, with spatially programmable detection. The wavefront control system uses a woofer tweeter approach, combining an electromagnetic mirror and a MEMS mirror and a single Shack Hartmann sensor. The SH sensor samples an 8 mm exit pupil and the subject is aligned to a region within this larger system pupil using a chin and forehead rest. A spot quality metric is calculated in real time for each lenslet. Individual lenslets that do not meet the quality metric are eliminated from the processing. Mirror shapes are smoothed outside the region of wavefront control when pupils are small. The system allows imaging even with smaller irregular pupils, however because the depth of field increases under these conditions, sectioning performance decreases. A retinal conjugate micromirror array selectively directs mid-range scatter to additional detectors. This improves detection of retinal capillaries even when the confocal image has poorer image quality that includes both photoreceptors and blood vessels.

3D Laser Scanning Assisted by Ordinary Plane Mirror for Non-direct Viewing Area

Directory of Open Access Journals (Sweden)

ZHANG Fan

2017-12-01

Full Text Available Terrestrial 3D laser scanning is one of principal methods to get the geometric information of object surface,and the integrity of the scanned object is a basic requirement in data acquisition. In order to solve the missing point cloud problem due to the scanning dead angle caused by confined working space,this paper proposes a method using ordinary plane mirror to obtain laser scanning data for non-direct viewing area according to the plane mirror reflection principle,analyzes the influence mechanism of the ordinary plane mirror on the propagation path and distance of laser beam,deduces the coordinate equation of the object point corresponding to the image point reflected by ordinary plane mirror in laser scanning. Given the laser scanning characteristic,this paper introduces a mirror reflection system included target balls and ordinary plane mirror,and expounds the system construction,system calibration and constructing method of system coordinate system. The feasibility and precision of the method are verified by experiments.

Planet-planet scattering leads to tightly packed planetary systems

OpenAIRE

Raymond, Sean N.; Barnes, Rory; Veras, Dimitri; Armitage, Philip J.; Gorelick, Noel; Greenberg, Richard

2009-01-01

The known extrasolar multiple-planet systems share a surprising dynamical attribute: they cluster just beyond the Hill stability boundary. Here we show that the planet-planet scattering model, which naturally explains the observed exoplanet eccentricity distribution, can reproduce the observed distribution of dynamical configurations. We calculated how each of our scattered systems would appear over an appropriate range of viewing geometries; as Hill stability is weakly dependent on the masse...

On whether mirror neurons play a significant role in processing affective prosody.

Science.gov (United States)

Ramachandra, Vijayachandra

2009-02-01

Several behavioral and neuroimaging studies have indicated that both right and left cortical structures and a few subcortical ones are involved in processing affective prosody. Recent investigations have shown that the mirror neuron system plays a crucial role in several higher-level functions such as empathy, theory of mind, language, etc., but no studies so far link the mirror neuron system with affective prosody. In this paper is a speculation that the mirror neuron system, which serves as a common neural substrate for different higher-level functions, may play a significant role in processing affective prosody via its connections with the limbic lobe. Actual research must apply electrophysiological and neuroimaging techniques to assess whether the mirror neuron systems underly affective prosody in humans.

RF-heating and plasma confinement studies in HANBIT mirror device

International Nuclear Information System (INIS)

Kwon, M.; Bak, J.G.; Choh, K.K.

2003-01-01

HANBIT is a magnetic mirror confinement device. Recently, with almost finishing the first campaign for the basic system development, it started the second campaign for the high-temperature plasma confinement physics study in mirror configuration. Here, we introduce briefly the HANBIT device and report initial physics experiments results on RF-plasma heating and confinement in the simple mirror configuration. It appears that the discharge characteristics of HANBIT are quite different from those in other mirror devices, and an explanation is presented to clarify the difference. (author)

Multiple pulse nanosecond laser induced damage threshold on hybrid mirrors

Science.gov (United States)

Vanda, Jan; Muresan, Mihai-George; Bilek, Vojtech; Sebek, Matej; Hanus, Martin; Lucianetti, Antonio; Rostohar, Danijela; Mocek, Tomas; Škoda, Václav

2017-11-01

So-called hybrid mirrors, consisting of broadband metallic surface coated with dielectric reflector designed for specific wavelength, becoming more important with progressing development of broadband mid-IR sources realized using parametric down conversion system. Multiple pulse nanosecond laser induced damage on such mirrors was tested by method s-on-1, where s stands for various numbers of pulses. We show difference in damage threshold between common protected silver mirrors and hybrid silver mirrors prepared by PVD technique and their variants prepared by IAD. Keywords: LIDT,

A Human Mirror Neuron System for Language: Perspectives from Signed Languages of the Deaf

Science.gov (United States)

Knapp, Heather Patterson; Corina, David P.

2010-01-01

Language is proposed to have developed atop the human analog of the macaque mirror neuron system for action perception and production [Arbib M.A. 2005. From monkey-like action recognition to human language: An evolutionary framework for neurolinguistics (with commentaries and author's response). "Behavioral and Brain Sciences, 28", 105-167; Arbib…

The Mirror Neuron System and Observational Learning: Implications for the Effectiveness of Dynamic Visualizations

Science.gov (United States)

van Gog, Tamara; Paas, Fred; Marcus, Nadine; Ayres, Paul; Sweller, John

2009-01-01

Learning by observing and imitating others has long been recognized as constituting a powerful learning strategy for humans. Recent findings from neuroscience research, more specifically on the mirror neuron system, begin to provide insight into the neural bases of learning by observation and imitation. These findings are discussed here, along…

Distributed sensing signal analysis of deformable plate/membrane mirrors

Science.gov (United States)

Lu, Yifan; Yue, Honghao; Deng, Zongquan; Tzou, Hornsen

2017-11-01

Deformable optical mirrors usually play key roles in aerospace and optical structural systems applied to space telescopes, radars, solar collectors, communication antennas, etc. Limited by the payload capacity of current launch vehicles, the deformable mirrors should be lightweight and are generally made of ultra-thin plates or even membranes. These plate/membrane mirrors are susceptible to external excitations and this may lead to surface inaccuracy and jeopardize relevant working performance. In order to investigate the modal vibration characteristics of the mirror, a piezoelectric layer is fully laminated on its non-reflective side to serve as sensors. The piezoelectric layer is segmented into infinitesimal elements so that microscopic distributed sensing signals can be explored. In this paper, the deformable mirror is modeled as a pre-tensioned plate and membrane respectively and sensing signal distributions of the two models are compared. Different pre-tensioning forces are also applied to reveal the tension effects on the mode shape and sensing signals of the mirror. Analytical results in this study could be used as guideline of optimal sensor/actuator placement for deformable space mirrors.

Six-strut arrangements for cartesian movements of mirrors

International Nuclear Information System (INIS)

Noll, T.; Zeschke, Th.; Reichardt, G.; Lammert, H.; Gudat, W.

2001-01-01

At BESSY a new six-strut arrangement for general small travel mirror adjustment mechanisms has been developed. This patented (Patent DE 10042802.5) arrangement allows very simple movements in all six linear and rotational degrees of freedom. The movements of the mirror are simply determined by moving either one drive, or up to three drives by the same amount. The first mirror adjustment systems of this design is successfully in operation since the start of BESSY II. Their performance and reliability is very satisfactory. This contribution will present the concepts

A one-dimensional ion beam figuring system for x-ray mirror fabrication

International Nuclear Information System (INIS)

Idir, Mourad; Huang, Lei; Bouet, Nathalie; Kaznatcheev, Konstantine; Vescovi, Matthew; Lauer, Ken; Conley, Ray; Rennie, Kent; Kahn, Jim; Nethery, Richard; Zhou, Lin

2015-01-01

We report on the development of a one-dimensional Ion Beam Figuring (IBF) system for x-ray mirror polishing. Ion beam figuring provides a highly deterministic method for the final precision figuring of optical components with advantages over conventional methods. The system is based on a state of the art sputtering deposition system outfitted with a gridded radio frequency inductive coupled plasma ion beam source equipped with ion optics and dedicated slit developed specifically for this application. The production of an IBF system able to produce an elongated removal function rather than circular is presented in this paper, where we describe in detail the technical aspect and present the first obtained results

A one-dimensional ion beam figuring system for x-ray mirror fabrication

Energy Technology Data Exchange (ETDEWEB)

Idir, Mourad, E-mail: midir@bnl.gov; Huang, Lei; Bouet, Nathalie; Kaznatcheev, Konstantine; Vescovi, Matthew; Lauer, Ken [NSLS-II, Brookhaven National Laboratory, P.O. Box 5000, Upton, New York 11973 (United States); Conley, Ray [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Rennie, Kent; Kahn, Jim; Nethery, Richard [Kaufman & Robinson, Inc., 1330 Blue Spruce Drive, Fort Collins, Colorado 80524 (United States); Zhou, Lin [College of Mechatronics and Automation, National University of Defense Technology, 109 Deya Road, Changsha, Hunan 410073 (China); Hu’nan Key Laboratory of Ultra-precision Machining Technology, Changsha, Hunan 410073 (China)

2015-10-15

We report on the development of a one-dimensional Ion Beam Figuring (IBF) system for x-ray mirror polishing. Ion beam figuring provides a highly deterministic method for the final precision figuring of optical components with advantages over conventional methods. The system is based on a state of the art sputtering deposition system outfitted with a gridded radio frequency inductive coupled plasma ion beam source equipped with ion optics and dedicated slit developed specifically for this application. The production of an IBF system able to produce an elongated removal function rather than circular is presented in this paper, where we describe in detail the technical aspect and present the first obtained results.

Design of GA thermochemical water-splitting process for the Mirror Advanced Reactor System

International Nuclear Information System (INIS)

Brown, L.C.

1983-04-01

GA interfaced the sulfur-iodine thermochemical water-splitting cycle to the Mirror Advanced Reactor System (MARS). The results of this effort follow as one section and part of a second section to be included in the MARS final report. This section describes the process and its interface to the reactor. The capital and operating costs for the hydrogen plant are described

Advanced Dispersed Fringe Sensing Algorithm for Coarse Phasing Segmented Mirror Telescopes

Science.gov (United States)

Spechler, Joshua A.; Hoppe, Daniel J.; Sigrist, Norbert; Shi, Fang; Seo, Byoung-Joon; Bikkannavar, Siddarayappa A.

2013-01-01

Segment mirror phasing, a critical step of segment mirror alignment, requires the ability to sense and correct the relative pistons between segments from up to a few hundred microns to a fraction of wavelength in order to bring the mirror system to its full diffraction capability. When sampling the aperture of a telescope, using auto-collimating flats (ACFs) is more economical. The performance of a telescope with a segmented primary mirror strongly depends on how well those primary mirror segments can be phased. One such process to phase primary mirror segments in the axial piston direction is dispersed fringe sensing (DFS). DFS technology can be used to co-phase the ACFs. DFS is essentially a signal fitting and processing operation. It is an elegant method of coarse phasing segmented mirrors. DFS performance accuracy is dependent upon careful calibration of the system as well as other factors such as internal optical alignment, system wavefront errors, and detector quality. Novel improvements to the algorithm have led to substantial enhancements in DFS performance. The Advanced Dispersed Fringe Sensing (ADFS) Algorithm is designed to reduce the sensitivity to calibration errors by determining the optimal fringe extraction line. Applying an angular extraction line dithering procedure and combining this dithering process with an error function while minimizing the phase term of the fitted signal, defines in essence the ADFS algorithm.

Variable reflectivity signal mirrors and signal response measurements

International Nuclear Information System (INIS)

Vine, Glenn de; Shaddock, Daniel A; McClelland, David E

2002-01-01

Future gravitational wave detectors will include some form of signal mirror in order to alter the signal response of the device. We introduce interferometer configurations which utilize a variable reflectivity signal mirror allowing a tunable peak frequency and variable signal bandwidth. A detector configured with a Fabry-Perot cavity as the signal mirror is compared theoretically with one using a Michelson interferometer for a signal mirror. A system for the measurement of the interferometer signal responses is introduced. This technique is applied to a power-recycled Michelson interferometer with resonant sideband extraction. We present broadband measurements of the benchtop prototype's signal response for a range of signal cavity detunings. This technique is also applicable to most other gravitational wave detector configurations

Variable reflectivity signal mirrors and signal response measurements

CERN Document Server

Vine, G D; McClelland, D E

2002-01-01

Future gravitational wave detectors will include some form of signal mirror in order to alter the signal response of the device. We introduce interferometer configurations which utilize a variable reflectivity signal mirror allowing a tunable peak frequency and variable signal bandwidth. A detector configured with a Fabry-Perot cavity as the signal mirror is compared theoretically with one using a Michelson interferometer for a signal mirror. A system for the measurement of the interferometer signal responses is introduced. This technique is applied to a power-recycled Michelson interferometer with resonant sideband extraction. We present broadband measurements of the benchtop prototype's signal response for a range of signal cavity detunings. This technique is also applicable to most other gravitational wave detector configurations.

Plasma cleaning of ITER first mirrors

Science.gov (United States)

Moser, L.; Marot, L.; Steiner, R.; Reichle, R.; Leipold, F.; Vorpahl, C.; Le Guern, F.; Walach, U.; Alberti, S.; Furno, I.; Yan, R.; Peng, J.; Ben Yaala, M.; Meyer, E.

2017-12-01

Nuclear fusion is an extremely attractive option for future generations to compete with the strong increase in energy consumption. Proper control of the fusion plasma is mandatory to reach the ambitious objectives set while preserving the machine’s integrity, which requests a large number of plasma diagnostic systems. Due to the large neutron flux expected in the International Thermonuclear Experimental Reactor (ITER), regular windows or fibre optics are unusable and were replaced by so-called metallic first mirrors (FMs) embedded in the neutron shielding, forming an optical labyrinth. Materials eroded from the first wall reactor through physical or chemical sputtering will migrate and will be deposited onto mirrors. Mirrors subject to net deposition will suffer from reflectivity losses due to the deposition of impurities. Cleaning systems of metallic FMs are required in more than 20 optical diagnostic systems in ITER. Plasma cleaning using radio frequency (RF) generated plasmas is currently being considered the most promising in situ cleaning technique. An update of recent results obtained with this technique will be presented. These include the demonstration of cleaning of several deposit types (beryllium, tungsten and beryllium proxy, i.e. aluminium) at 13.56 or 60 MHz as well as large scale cleaning (mirror size: 200 × 300 mm2). Tests under a strong magnetic field up to 3.5 T in laboratory and first experiments of RF plasma cleaning in EAST tokamak will also be discussed. A specific focus will be given on repetitive cleaning experiments performed on several FM material candidates.

Activity-Dependent Neurorehabilitation Beyond Physical Trainings: "Mental Exercise" Through Mirror Neuron Activation.

Science.gov (United States)

Yuan, Ti-Fei; Chen, Wei; Shan, Chunlei; Rocha, Nuno; Arias-Carrión, Oscar; Paes, Flávia; de Sá, Alberto Souza; Machado, Sergio

2015-01-01

The activity dependent brain repair mechanism has been widely adopted in many types of neurorehabilitation. The activity leads to target specific and non-specific beneficial effects in different brain regions, such as the releasing of neurotrophic factors, modulation of the cytokines and generation of new neurons in adult hood. However physical exercise program clinically are limited to some of the patients with preserved motor functions; while many patients suffered from paralysis cannot make such efforts. Here the authors proposed the employment of mirror neurons system in promoting brain rehabilitation by "observation based stimulation". Mirror neuron system has been considered as an important basis for action understanding and learning by mimicking others. During the action observation, mirror neuron system mediated the direct activation of the same group of motor neurons that are responsible for the observed action. The effect is clear, direct, specific and evolutionarily conserved. Moreover, recent evidences hinted for the beneficial effects on stroke patients after mirror neuron system activation therapy. Finally some music-relevant therapies were proposed to be related with mirror neuron system.

Beam-guiding system for Rutherford-scattering diagnostic at TEXTOR

International Nuclear Information System (INIS)

Cosler, A; Bertschinger, G.; Kemmereit, E.; Ven, H.W. van der; Barbian, E.P.; Blokland, A.A.E. van

1988-01-01

A beam-guiding system for a neutral beam probe diagnostic has been developed for implementation at TEXTOR. Energetic helium atoms scattered on the plasma ions provide information about the local ion temperature. Time resolution is attained by sampling scattered particles measured individually by a time-of-flight analyser. The mechanical supports have been designed for lateral and angular movement of the beam-guiding system to be used for radial scanning of the torus and for optimization of the scattering angle. The parameters of the probing beam itself can be controlled jby a small beam profile diagnsotic. Provisions are made to observe separately the radial or axial component of the ion velocity distribution. (author). 10 refs.; 7 figs

ICRF heating of passing ions in a thermal barrier tandem mirror

International Nuclear Information System (INIS)

Molvik, A.W.; Dimonte, G.; Campbell, R.; Barter, J.; Cummins, W.F.; Falabella, S.; Poulsen, P.

1985-05-01

Ion heating is used in the central cells of tandem mirrors to reduce the collisional trapping of passing ions in the end cell thermal barriers. In this paper, we reevaluate ICRF heating of the TMX-U central cell in two limits. The first we term isotropic, because we impose the condition that ions heated in the perpendicular direction be confined for at least one 90 0 scattering time, thereby heating the passing ions. The second we call anisotropic heating. It uses higher ICRF power to mirror trap a majority of the ions near the midplane, thereby reducing the density and collisionality of passing ions. Anisotropic heating has the advantage of increasing with ICRF power, whereas isotropic heating is limited by ion collisionality. Both techniques require gas fueling near the central cell midplane, with an ion cyclotron resonance toward each end cell to heat the cold ions

The Thomson scattering system at DANTE

International Nuclear Information System (INIS)

Gadeberg, M.

1983-08-01

The construction and operation of the 90 deg Thomson Scattering diagnostic at DANTE is described. The system is based on a double-pulse ruby laser and a three channel spectrometer. Two single point measurements can be made during each plasma discharge. (Auth.)

Plasma cleaning of ITER First Mirrors in magnetic field

Energy Technology Data Exchange (ETDEWEB)

Moser, Lucas, E-mail: lucas.moser@unibas.ch [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Steiner, Roland [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Leipold, Frank; Reichle, Roger [ITER Organization, Route de Vinon-sur-Verdon, 13115 St Paul-lez-Durance (France); Marot, Laurent; Meyer, Ernst [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

2015-08-15

To avoid reflectivity losses in ITER’s optical diagnostic systems, plasma sputtering of metallic First Mirrors is foreseen in order to remove deposits coming from the main wall (mainly beryllium and tungsten). Therefore plasma cleaning has to work on large mirrors (up to a size of 200 × 300 mm) and under the influence of strong magnetic fields (several Tesla). This work presents the results of plasma cleaning of aluminium and aluminium oxide (used as beryllium proxy) deposited on molybdenum mirrors. Using radio frequency (13.56 MHz) argon plasma, the removal of a 260 nm mixed aluminium/aluminium oxide film deposited by magnetron sputtering on a mirror (98 mm diameter) was demonstrated. 50 nm of pure aluminium oxide were removed from test mirrors (25 mm diameter) in a magnetic field of 0.35 T for various angles between the field lines and the mirrors surfaces. The cleaning efficiency was evaluated by performing reflectivity measurements, Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy.

Evolution of the mirror approach to fusion: some conjectures

International Nuclear Information System (INIS)

Post, R.E.

1984-01-01

Some possible directions for the future evolution of the mirror approach to fusion are outlined, in the context of economically-motivated criteria. Speculations are given as to the potential advantages, economic and otherwise, of the use of axially-symmetric systems, operated in semi-collisional regimes of lower Q (fusion power balance ratio) than that projected for present-day tandem mirror designs. These regims include barely tandem modes, and ion-heated modes, in association with higher efficiency direct conversion. Another possible economically advantageous approach mentioned is the use of a tandem mirror plasma to stabilize a FRM (field-reversed mirror) plasma, with potential synergistic advantages

NiCrNx interlayer thickness dependence of spectral performance and environmental durability of protected-silver mirrors

Science.gov (United States)

Xu, Xu; Li, Bincheng; He, Wenyan; Wang, Changjun; Wei, Ming

2018-04-01

Gemini-style protected-silver mirror (Sub / NiCrNx / Ag / NiCrNx / SiNx / Air) is a suitable choice for optical instruments requiring both long-term environmental durability and high broadband reflectance. Three Gemini-style protected-silver mirrors with NiCrNx interlayer thicknesses between 0.1 and 0.6 nm were prepared by magnetron sputtering, and the dependences of spectral properties and environmental durability of these protected-silver mirrors on the thickness of NiCrNx interlayer between the silver layer and SiNx layer were investigated in-depth. The reflectance, transmittance and total scattering loss measurements, optical microscope, and scanning electron microscope imaging were employed to characterize the spectral properties and surface morphology, and accelerated environmental tests, including humidity test and salt fog test, were applied to investigate the environmental durability. The experimental results showed that both optical and corrosion-resistant properties of protected-silver mirrors were NiCrNx interlayer thickness dependent, and an optimum NiCrNx interlayer thickness should be ˜0.3 nm for Gemini-style protected-silver mirrors to have reasonably both high reflectance in a broadband spectral range from visible to far infrared and good corrosion resistance for long-lifetime applications in harsh environments.

Overview of deformable mirror technologies for adaptive optics and astronomy

Science.gov (United States)

Madec, P.-Y.

2012-07-01

From the ardent bucklers used during the Syracuse battle to set fire to Romans’ ships to more contemporary piezoelectric deformable mirrors widely used in astronomy, from very large voice coil deformable mirrors considered in future Extremely Large Telescopes to very small and compact ones embedded in Multi Object Adaptive Optics systems, this paper aims at giving an overview of Deformable Mirror technology for Adaptive Optics and Astronomy. First the main drivers for the design of Deformable Mirrors are recalled, not only related to atmospheric aberration compensation but also to environmental conditions or mechanical constraints. Then the different technologies available today for the manufacturing of Deformable Mirrors will be described, pros and cons analyzed. A review of the Companies and Institutes with capabilities in delivering Deformable Mirrors to astronomers will be presented, as well as lessons learned from the past 25 years of technological development and operation on sky. In conclusion, perspective will be tentatively drawn for what regards the future of Deformable Mirror technology for Astronomy.

Development of in situ cleaning techniques for diagnostic mirrors in ITER

International Nuclear Information System (INIS)

Litnovsky, A.; Laengner, M.; Matveeva, M.; Schulz, Ch.; Marot, L.; Voitsenya, V.S.; Philipps, V.; Biel, W.; Samm, U.

2011-01-01

Mirrors will be used in all optical and laser-based diagnostic systems of ITER. In the severe environment, the optical characteristics of mirrors will be degraded, hampering the entire performance of the respective diagnostics. A minute impurity deposition of 20 nm of carbon on the mirror is sufficient to decrease the mirror reflectivity by tens of percent outlining the necessity of the mirror cleaning in ITER. The results of R and D on plasma cleaning of molybdenum diagnostic mirrors are reported. The mirrors contaminated with amorphous carbon films in the laboratory conditions and in the tokamaks were cleaned in steady-state hydrogenic plasmas. The maximum cleaning efficiency of 4.2 nm/min was reached for the laboratory and soft tokamak hydrocarbon films, whereas for the hard tokamak films the carbidization of mirrors drastically decreased the cleaning efficiency down to 0.016 nm/min. This implies the necessity of sputtering cleaning of contaminated mirrors as the only reliable tool to remove the deposits by plasma cleaning. An overview of R and D program on mirror cleaning is provided along with plans for further studies and the recommendations for ITER mirror-based diagnostics.

Lateralization of the human mirror neuron system.

Science.gov (United States)

Aziz-Zadeh, Lisa; Koski, Lisa; Zaidel, Eran; Mazziotta, John; Iacoboni, Marco

2006-03-15

A cortical network consisting of the inferior frontal, rostral inferior parietal, and posterior superior temporal cortices has been implicated in representing actions in the primate brain and is critical to imitation in humans. This neural circuitry may be an evolutionary precursor of neural systems associated with language. However, language is predominantly lateralized to the left hemisphere, whereas the degree of lateralization of the imitation circuitry in humans is unclear. We conducted a functional magnetic resonance imaging study of imitation of finger movements with lateralized stimuli and responses. During imitation, activity in the inferior frontal and rostral inferior parietal cortex, although fairly bilateral, was stronger in the hemisphere ipsilateral to the visual stimulus and response hand. This ipsilateral pattern is at variance with the typical contralateral activity of primary visual and motor areas. Reliably increased signal in the right superior temporal sulcus (STS) was observed for both left-sided and right-sided imitation tasks, although subthreshold activity was also observed in the left STS. Overall, the data indicate that visual and motor components of the human mirror system are not left-lateralized. The left hemisphere superiority for language, then, must be have been favored by other types of language precursors, perhaps auditory or multimodal action representations.

The manufacturing and metrology of off-axis mirrors

Science.gov (United States)

Penzkofer, Karlheinz; Rascher, Rolf; Küpper, Lutz; Liebl, Johannes

2015-10-01

Especially in the area of the large mirror manufacturing only a few manufacturers are capable to produce optical surfaces of high quality. Therefore a deterministic process should be developed in the project IFasO. In the field of telescope optics off-axis optical systems are becoming increasingly important. These systems try to avoid an obstructing of the incoming light by moving the secondary mirror out of the primary mirror's optical axis. This advantage leads to an increasing market for this type of optical surface. Until now off-axis mirrors were difficult or almost impossible to produce. With the processes developed in IFasO, high quality mirrors become possible. For this reason, this paper describes the manufacturing of off-axis surfaces and its problems. The mirror production used in the project IFasO is based on the specific design of the CNC center developed by the company Optotech. This center UPG2000 is capable of grinding, polishing, sagitta measurement and interferometric measurement in one mounting of the specimen. Usually a large optics has to be transported during their manufacturing after every individual process step. There is always a risk of damage of the specimen. The exact orientation of the surface relatively to the tool position is also required. This takes a huge amount of time and makes up most of the production time. In this presentation the use of UPG2000 and the next steps within the process development are described. In the current status the manufacturing of large off-axis elements with a PV < λ/10 rms is reproducible.

Design for an aberration corrected scanning electron microscope using miniature electron mirrors.

Science.gov (United States)

Dohi, Hideto; Kruit, Pieter

2018-06-01

Resolution of scanning electron microscopes (SEMs) is determined by aberrations of the objective lens. It is well known that both spherical and chromatic aberrations can be compensated by placing a 90-degree bending magnet and an electron mirror in the beam path before the objective lens. Nevertheless, this approach has not led to wide use of these aberration correctors, partly because aberrations of the bending magnet can be a serious problem. A mirror corrector with two mirrors placed perpendicularly to the optic axis of an SEM and facing each other is proposed. As a result, only small-angle magnetic deflection is necessary to guide the electron beam around the top mirror to the bottom mirror and around the bottom mirror to the objective lens. The deflection angle, in the order of 50 mrad, is sufficiently small to avoid deflection aberrations. In addition, lateral dispersion at the sample plane can be avoided by making the deflection fields symmetric. Such a corrector system is only possible if the incoming beam can pass the top mirror at a distance in the order of millimeters, without being disturbed by the electric fields of electrodes of the mirror. It is proposed that condition can be satisfied with micro-scale electron optical elements fabricated by using MEMS technology. In the proposed corrector system, the micro-mirrors have to provide the exact negative spherical and chromatic aberrations for correcting the aberration of the objective lens. This exact tuning is accomplished by variable magnification between the micro-mirrors and the objective lens using an additional transfer lens. Extensive optical calculations are reported. Aberrations of the micro-mirrors were analyzed by numerical calculation. Dispersion and aberrations of the deflectors were calculated by using an analytical field model. Combination aberrations caused by the off-axis position of dispersive rays in the mirrors and objective lens were also analyzed. It is concluded that the proposed

Clinical characteristics of mirror syndrome: a comparison of 10 cases of mirror syndrome with non-mirror syndrome fetal hydrops cases.

Science.gov (United States)

Hirata, Go; Aoki, Shigeru; Sakamaki, Kentaro; Takahashi, Tsuneo; Hirahara, Fumiki; Ishikawa, Hiroshi

2016-01-01

To investigate clinical features of mirror syndrome. We retrospectively reviewed 71 cases of fetal hydrops with or without mirror syndrome, and compared with respect to maternal age, the body mass index, the primipara rate, the gestational age at delivery, the timing of fetal hydrops onset, the severity of fetal edema, placental swelling, the laboratory data and the fetal mortality. The data are expressed as the medians. Mirror syndrome developed in 29% (10/35) of the cases with fetal hydrops. In mirror group, the onset time of fetal hydrops was significantly earlier (29 weeks versus 31 weeks, p = 0.011), and the severity of fetal hydrops (fetal edema/biparietal diameter) was significantly higher than non-mirror group (0.23 versus 0.16, p < 0.001). There was significantly higher serum human chorionic gonadotropin (hCG) (453,000 IU/L versus 80,000 IU/L, p < 0.001) and lower hemoglobin (8.9 g/dL versus 10.1 g/dL, p =0.002), hypoalbuminemia (2.3 mg/dL versus 2.7 mg/dL, p = 0.007), hyperuricemia (6.4 mg/dL versus 5.0 mg/dL, p = 0.043) in mirror group. Mirror syndrome is occurred frequently in early and severe fetal hydrops and cause hemodilution and elevation of serum hCG.

Thermal performance of the ATST secondary mirror

Science.gov (United States)

Cho, Myung K.; DeVries, Joe; Hansen, Eric

2007-12-01

The Advanced Technology Solar Telescope (ATST) has a 4.24m off-axis primary mirror designed to deliver diffractionlimited images of the sun. Its baseline secondary mirror (M2) design uses a 0.65m diameter Silicon Carbide mirror mounted kinematically by a bi-pod flexure mechanism at three equally spaced locations. Unlike other common telescopes, the ATST M2 is to be exposed to a significant solar heat loading. A thermal management system (TMS) will be developed to accommodate the solar loading and minimize "mirror seeing effect" by controlling the temperature difference between the M2 optical surface and the ambient air at the site. Thermo-elastic analyses for steady state thermal behaviors of the ATST secondary mirror was performed using finite element analysis by I-DEAS TM and PCRINGE TM for the optical analysis. We examined extensive heat transfer simulation cases and their results were discussed. The goal of this study is to establish thermal models by I-DEAS for an adequate thermal environment. These thermal models will be useful for estimating segment thermal responses. Current study assumes a few sample time dependent thermal loadings to synthesize the operational environment.

Performance evaluations of the ATST secondary mirror

Science.gov (United States)

Cho, Myung K.; DeVries, Joseph; Hansen, Eric

2007-09-01

The Advanced Technology Solar Telescope (ATST) has a 4.24m off-axis primary mirror designed to deliver diffraction-limited images of the sun. Its baseline secondary mirror (M2) design uses a 0.65m diameter Silicon Carbide mirror mounted kinematically by a bi-pod flexure mechanism at three equally spaced locations. Unlike other common telescopes, the ATST M2 is to be exposed to a significant solar heat loading. A thermal management system will be developed to accommodate the solar loading and minimize "mirror seeing effect" by controlling the temperature difference between the M2 optical surface and the ambient air at the site. Thermo-elastic analyses for steady state thermal behaviors of the ATST secondary mirror was performed using finite element analysis by I-DEAS TM and PCFRINGE TM for the optical analysis. We examined extensive heat transfer simulation cases and their results are discussed. The goal of this study is to evaluate the optical performances of M2 using thermal models and mechanical models. Thermal responses from the models enable us to manipulate time dependent thermal loadings to synthesize the operational environment for the design and development of TMS.

Scattering from correlations in colloidal systems

International Nuclear Information System (INIS)

Hayter, J.B.

1984-01-01

Colloidal suspensions typically exhibit spatial correlations over distances of order 10-10 4 A, corresponding either to the size of individual particles (e.g., polymer chains, surfactant micelles) or to the range of interaction between particles (e.g., charged polymer lattices at low ionic strength). Apart from having fundamental intrinsic interest, such systems are also extremely useful as model systems with which to study, for example, non-Newtonian hydrodynamics, since temporal correlations are generally much longer lived (10 -8 -10 -3 sec) than those found in simple atomic or small molecular systems (10 -13 -10 -10 sec). Colloids have long been the subject of macroscopic phenomenological research (on rheological properties, for example), but it is only recently that microscopic light, x-ray and neutron scattering techniques have been applied to their study, in large part because of theoretical difficulties in understanding the scattering from dense liquid-like systems of interacting particles. For spherical colloids, such theoretical problems have now been largely overcome, and for anisotropic colloids experimental techniques are being developed which circumvent the intractable theoretical areas. This paper will first review some static light and small-angle neutron scattering (SANS) results on colloidal suspensions, both at equilibrium and in steady-state non-equilibrium situations, and will then discuss some dynamic measurements on polymer solutions and melts made using the neutron spin-echo (NSE) technique. Emphasis is placed on experiments which have a possible counterpart in synchrotron radiation studies. In particular, NSE extends the results of photon correlation spectroscopy (PCS) to larger momentum transfers and shorter time-scales than are available with visible light, and the extension of PCS to short wavelength on a synchrotron source would be of similar fundamental interest

Coherent scattering of electromagnetic radiation by a polarized particle system

International Nuclear Information System (INIS)

Agre, M.Ya.; Rapoport, L.P.

1996-01-01

The paper deals with the development of the theory of coherent scattering of electromagnetic waves by a polarized atom or molecular system. Peculiarities of the angular distribution and polarization peculiarities of scattered radiation are discussed

Small mirror fusion reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Schultz, K.R.; Smith, A.C. Jr.

1978-01-01

Basic requirements for the pilot plants are that they produce a net product and that they have a potential for commercial upgrade. We have investigated a small standard mirror fusion-fission hybrid, a two-component tandem mirror hybrid, and two versions of a field-reversed mirror fusion reactor--one a steady state, single cell reactor with a neutral beam-sustained plasma, the other a moving ring field-reversed mirror where the plasma passes through a reaction chamber with no energy addition

Study of fusion product effects in field-reversed mirrors

International Nuclear Information System (INIS)

Driemeyer, D.E.

1980-01-01

The effect of fusion products (fps) on Field-Reversed Mirror (FRM) reactor concepts has been evaluated through the development of two new computer models. The first code (MCFRM) treats fps as test particles in a fixed background plasma, which is represented as a fluid. MCFRM includes a Monte Carlo treatment of Coulomb scattering and thus provides an accurate treatment of fp behavior even at lower energies where pitch-angle scattering becomes important. The second code (FRMOD) is a steady-state, globally averaged, two-fluid (ion and electron), point model of the FRM plasma that incorporates fp heating and ash buildup values which are consistent with the MCFRM calculations. These codes have been used extensively in the development of an advanced-fuel FRM reactor design (SAFFIRE). A Catalyzed-D version of the plant is also discussed along with an investigation of the steady-state energy distribution of fps in the FRM. User guides for the two computer codes are also included

Impact of large field angles on the requirements for deformable mirror in imaging satellites

Science.gov (United States)

Kim, Jae Jun; Mueller, Mark; Martinez, Ty; Agrawal, Brij

2018-04-01

For certain imaging satellite missions, a large aperture with wide field-of-view is needed. In order to achieve diffraction limited performance, the mirror surface Root Mean Square (RMS) error has to be less than 0.05 waves. In the case of visible light, it has to be less than 30 nm. This requirement is difficult to meet as the large aperture will need to be segmented in order to fit inside a launch vehicle shroud. To reduce this requirement and to compensate for the residual wavefront error, Micro-Electro-Mechanical System (MEMS) deformable mirrors can be considered in the aft optics of the optical system. MEMS deformable mirrors are affordable and consume low power, but are small in size. Due to the major reduction in pupil size for the deformable mirror, the effective field angle is magnified by the diameter ratio of the primary and deformable mirror. For wide field of view imaging, the required deformable mirror correction is field angle dependant, impacting the required parameters of a deformable mirror such as size, number of actuators, and actuator stroke. In this paper, a representative telescope and deformable mirror system model is developed and the deformable mirror correction is simulated to study the impact of the large field angles in correcting a wavefront error using a deformable mirror in the aft optics.

Associative learning is necessary but not sufficient for mirror neuron development

OpenAIRE

Bonaiuto, James

2014-01-01

Existing computational models of the mirror system demonstrate the additional circuitry needed for mirror neurons to display the range of properties that they exhibit. Such models emphasize the need for existing connectivity to form visuomotor associations, processing to reduce the space of possible inputs, and demonstrate the role neurons with mirror properties might play in monitoring one's own actions.

Associative learning is necessary but not sufficient for mirror neuron development.

Science.gov (United States)

Bonaiuto, James

2014-04-01

Existing computational models of the mirror system demonstrate the additional circuitry needed for mirror neurons to display the range of properties that they exhibit. Such models emphasize the need for existing connectivity to form visuomotor associations, processing to reduce the space of possible inputs, and demonstrate the role neurons with mirror properties might play in monitoring one's own actions.

Heavy particle scattering by atomic and nuclear systems

International Nuclear Information System (INIS)

Lazauskas, R.

2003-10-01

In this thesis quantum mechanical non-relativistic few-body problem is discussed. Basing on fundamentals ideas from Faddeev and Yakubovski three and four body equations are formulated and solved for fermionic atomic and nuclear systems. Former equations are modified to include long range interactions. Original results for nuclear and molecular physics were obtained: -) positively charged particle scattering on hydrogen atoms was considered; predictions for π + → H, μ + → H and p + → H scattering lengths were given. Existence of an unknown, very weakly bound H + 2 bound state was predicted. -) Motivated by the possible observation of bound four neutron structure at GANIL we have studied compatibility of such an existence within the current nuclear interaction models. -) 4 nucleon scattering at low energies was investigated. Results for n → 3 H, p → 3 H and p → 3 He systems were compared with the experimental data. Validity of realistic nucleon-nucleon interaction models is questioned. (author)

Design of Efficient Mirror Adder in Quantum- Dot Cellular Automata

Science.gov (United States)

Mishra, Prashant Kumar; Chattopadhyay, Manju K.

2018-03-01

Lower power consumption is an essential demand for portable multimedia system using digital signal processing algorithms and architectures. Quantum dot cellular automata (QCA) is a rising nano technology for the development of high performance ultra-dense low power digital circuits. QCA based several efficient binary and decimal arithmetic circuits are implemented, however important improvements are still possible. This paper demonstrate Mirror Adder circuit design in QCA. We present comparative study of mirror adder cells designed using conventional CMOS technique and mirror adder cells designed using quantum-dot cellular automata. QCA based mirror adders are better in terms of area by order of three.

Preliminary project of s Thomson scattering system for the ETE tokamak

International Nuclear Information System (INIS)

Berni, Luiz Angelo

1997-01-01

This report presents the preliminary project of the injection and laser light block system for the Thomson (ET) scattering diagnostic to be implanted at the ETE spheric tokamak of the Instituto Nacional de Pesquisas Espaciais (INPE/LAP). Also, a scanning system for the optics of scattered light

Bronze rainbow hologram mirrors

Science.gov (United States)

Dawson, P.

2006-02-01

This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.

Review of the Tandem Mirror Experiment-Upgrade (TMX-U) machine-parameter-instrumentation system

International Nuclear Information System (INIS)

Kane, R.J.; Coffield, F.E.; Coutts, G.W.; Hornady, R.S.

1983-01-01

The Tandem Mirror Experiment-Upgrade (TMX-U) machine consists of seven major machine subsystems: magnet system, neutral beam system, microwave heating (ECRH), ion heating (ICRH), gas fueling, stream guns, and vacuum system. Satisfactory performance of these subsystems is necessary to achieve the experimental objectives planned for TMX-U operations. Since the performance quality of the subsystem is important and can greatly affect plasma parameters, a 233-channel instrumentation system has been installed. Data from the instrumentation system are acquired and stored with the plasma diagnostic information. Thus, the details of the machine performance are available during post-shot analysis. This paper describes all the machine-parameter-instrumentation hardware, presents some typical data, and outlines how the data are used

Mirror mounts designed for the Advanced Photon Source SRI-CAT

International Nuclear Information System (INIS)

Shu, D.; Benson, C.; Chang, J.; Barraza, J.; Kuzay, T. M.; Alp, E. E.; Sturhahn, W.; Lai, B.; McNulty, I.; Randall, K.; Srajer, G.; Xu, Z.; Yun, W.

1997-01-01

Use of a mirror for beamlines at third-generation synchrotron radiation facilities, such as the Advanced Photon Source (APS) at Argonne National Laboratory, has many advantages. [Yun et al., Rev. Sci. Instrum. 67(9)(1996)CD-ROM] A mirror as a first optical component provides significant reduction in the beam peak heat flux and total power on the downstream monochromator and simplifies the bremsstrahlung shielding design for the beamline transport. It also allows us to have a system for multibeamline branching and switching. More generally, a mirror is used for beam focusing and/or low-pass filtering. Six different mirror mounts have been designed for the SRI-CAT beamlines. Four of them are designed as water-cooled mirrors for white or pink beam use, and the other two are for monochromatic beam use. Mirror mount designs, including vacuum vessel structure and precision supporting stages, are presented in this paper

Conception and design of a control and monitoring system for the mirror alignment of the CBM RICH detector

Science.gov (United States)

Bendarouach, J.

2016-08-01

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Anti-proton and Ion Research (FAIR) complex will investigate the phase diagram of strongly interacting matter at high baryon density and moderate temperatures created in A+A collisions. For the SIS100 accelerator, the foreseen beam energy will range up to 11 AGeV for the heaviest nuclei. One of the key detector components required for the CBM physics program is the Ring Imaging CHerenkov (RICH) detector, which is developed for efficient and clean electron identification and pion suppression. An important aspect to guarantee a stable operation of the RICH detector is the alignment of the mirrors. A qualitative alignment control procedure for the mirror system has been implemented in the CBM RICH prototype detector and tested under real conditions at the CERN PS/T9 beamline. Collected data and results of image processing are reviewed and discussed. In parallel a quantitative method using recorded data has also been employed to compute mirror displacements of the RICH mirrors. Results based on simulated events and the limits of the method are presented and discussed as well. If mirror misalignment is detected, it can be subsequently included and rectified by correction routines. A first correction routine is presented and a comparison between misaligned, corrected and ideal geometries is shown.

Conception and design of a control and monitoring system for the mirror alignment of the CBM RICH detector

International Nuclear Information System (INIS)

Bendarouach, J

2016-01-01

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Anti-proton and Ion Research (FAIR) complex will investigate the phase diagram of strongly interacting matter at high baryon density and moderate temperatures created in A+A collisions. For the SIS100 accelerator, the foreseen beam energy will range up to 11 AGeV for the heaviest nuclei. One of the key detector components required for the CBM physics program is the Ring Imaging CHerenkov (RICH) detector, which is developed for efficient and clean electron identification and pion suppression. An important aspect to guarantee a stable operation of the RICH detector is the alignment of the mirrors. A qualitative alignment control procedure for the mirror system has been implemented in the CBM RICH prototype detector and tested under real conditions at the CERN PS/T9 beamline. Collected data and results of image processing are reviewed and discussed. In parallel a quantitative method using recorded data has also been employed to compute mirror displacements of the RICH mirrors. Results based on simulated events and the limits of the method are presented and discussed as well. If mirror misalignment is detected, it can be subsequently included and rectified by correction routines. A first correction routine is presented and a comparison between misaligned, corrected and ideal geometries is shown. (paper)

Photon scattering from a system of multilevel quantum emitters. I. Formalism

Science.gov (United States)

Das, Sumanta; Elfving, Vincent E.; Reiter, Florentin; Sørensen, Anders S.

2018-04-01

We introduce a formalism to solve the problem of photon scattering from a system of multilevel quantum emitters. Our approach provides a direct solution of the scattering dynamics. As such the formalism gives the scattered fields' amplitudes in the limit of a weak incident intensity. Our formalism is equipped to treat both multiemitter and multilevel emitter systems, and is applicable to a plethora of photon-scattering problems, including conditional state preparation by photodetection. In this paper, we develop the general formalism for an arbitrary geometry. In the following paper (part II) S. Das et al. [Phys. Rev. A 97, 043838 (2018), 10.1103/PhysRevA.97.043838], we reduce the general photon-scattering formalism to a form that is applicable to one-dimensional waveguides and show its applicability by considering explicit examples with various emitter configurations.

Dual wavelength multiple-angle light scattering system for cryptosporidium detection

Science.gov (United States)

Buaprathoom, S.; Pedley, S.; Sweeney, S. J.

2012-06-01

A simple, dual wavelength, multiple-angle, light scattering system has been developed for detecting cryptosporidium suspended in water. Cryptosporidium is a coccidial protozoan parasite causing cryptosporidiosis; a diarrheal disease of varying severity. The parasite is transmitted by ingestion of contaminated water, particularly drinking-water, but also accidental ingestion of bathing-water, including swimming pools. It is therefore important to be able to detect these parasites quickly, so that remedial action can be taken to reduce the risk of infection. The proposed system combines multiple-angle scattering detection of a single and two wavelengths, to collect relative wavelength angle-resolved scattering phase functions from tested suspension, and multivariate data analysis techniques to obtain characterizing information of samples under investigation. The system was designed to be simple, portable and inexpensive. It employs two diode lasers (violet InGaN-based and red AlGaInP-based) as light sources and silicon photodiodes as detectors and optical components, all of which are readily available. The measured scattering patterns using the dual wavelength system showed that the relative wavelength angle-resolved scattering pattern of cryptosporidium oocysts was significantly different from other particles (e.g. polystyrene latex sphere, E.coli). The single wavelength set up was applied for cryptosporidium oocysts'size and relative refractive index measurement and differential measurement of the concentration of cryptosporidium oocysts suspended in water and mixed polystyrene latex sphere suspension. The measurement results showed good agreement with the control reference values. These results indicate that the proposed method could potentially be applied to online detection in a water quality control system.

Measurement of charge symmetry breaking in np elastic scattering at 350 MeV

International Nuclear Information System (INIS)

Abegg, R.; Berdoz, A.R.; Birchall, J.

1994-10-01

TRIUMF experiment 369, a measurement of charge symmetry breaking in np elastic scattering at 350 MeV, has completed data taking. Scattering asymmetries were measured with a polarized (unpolarized) neutron beam incident on an unpolarized (polarized) frozen spin target. Coincident scattered neutrons and recoil protons were detected by a mirror symmetric detection system in the center-of-mass angle range from 50 deg - 90 deg. A preliminary result for the difference of the zero-crossing angles, where analyzing powers cross zero, is Δθ cm = 0.445 deg ± 0.054 deg (stat.) ± 0.051 deg (syst.) based on fits over the angle range 53.4 deg ≤ θ cm ≤ 86.9 deg. The difference of the analyzing powers ΔA ≡ A n - A p , where the subscripts denote polarized nucleons, was deduced with dA/dθ cm = (-1.35 ± 0.05) x 10 -2 deg -1 to be [60 ± 7(stat.) ± 7(syst.) ± 2(syst.)] x 10 -4 . (author). 11 refs., 6 figs

Fragility of complexity biophysical systems by neutron scattering

Energy Technology Data Exchange (ETDEWEB)

Magazu, Salvatore [Dipartimento di Fisica, Universita di Messina, P.O. Box 55, I-98166 Messina (Italy)]. E-mail: smagazu@unime.it; Migliardo, Federica [Dipartimento di Fisica, Universita di Messina, P.O. Box 55, I-98166 Messina (Italy); Bellocco, Ersilia [Dipartimento di Chimica Organica e Biologica, Universita di Messina, I-98166 Messina (Italy); Lagana, Giuseppina [Dipartimento di Chimica Organica e Biologica, Universita di Messina, I-98166 Messina (Italy); Mondelli, Claudia [CNR-INFM OGG and CRS-SOFT, c/o ILL, 6 Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France)

2006-11-15

Neutron scattering is an exceptional tool to investigate structural and dynamical properties of systems of biophysical interest, such as proteins, enzymes, lipids and sugars. Moreover, elastic neutron scattering enhances the investigation of atomic motions in hydrated proteins in a wide temperature range and on the picosecond timescale. Homologous disaccharides, such as trehalose, maltose and sucrose, are cryptobiotic substances, since they allow to many organisms to undergo in a 'suspended life' state, known as cryptobiosis in extreme environmental conditions. The present paper is aimed to discuss the fragility degree of disaccharides, as evaluated of the temperature dependence of the mean square displacement by elastic neutron scattering, in order to link this feature with their bioprotective functions.

Mirror plasma apparatus

International Nuclear Information System (INIS)

Moir, R.W.

1981-01-01

A mirror plasma apparatus which utilizes shielding by arc discharge to form a blanket plasma and lithium walls to reduce neutron damage to the wall of the apparatus. An embodiment involves a rotating liquid lithium blanket for a tandem mirror plasma apparatus wherein the first wall of the central mirror cell is made of liquid lithium which is spun with angular velocity great enough to keep the liquid lithium against the first material wall, a blanket plasma preventing the lithium vapor from contaminating the plasma

Mesmerising mirror neurons.

Science.gov (United States)

Heyes, Cecilia

2010-06-01

Mirror neurons have been hailed as the key to understanding social cognition. I argue that three currents of thought-relating to evolution, atomism and telepathy-have magnified the perceived importance of mirror neurons. When they are understood to be a product of associative learning, rather than an adaptation for social cognition, mirror neurons are no longer mesmerising, but they continue to raise important questions about both the psychology of science and the neural bases of social cognition. Copyright 2010 Elsevier Inc. All rights reserved.

Correcting the wavefront aberration of membrane mirror based on liquid crystal spatial light modulator

Science.gov (United States)

Yang, Bin; Wei, Yin; Chen, Xinhua; Tang, Minxue

2014-11-01

Membrane mirror with flexible polymer film substrate is a new-concept ultra lightweight mirror for space applications. Compared with traditional mirrors, membrane mirror has the advantages of lightweight, folding and deployable, low cost and etc. Due to the surface shape of flexible membrane mirror is easy to deviate from the design surface shape, it will bring wavefront aberration to the optical system. In order to solve this problem, a method of membrane mirror wavefront aberration correction based on the liquid crystal spatial light modulator (LCSLM) will be studied in this paper. The wavefront aberration correction principle of LCSLM is described and the phase modulation property of a LCSLM is measured and analyzed firstly. Then the membrane mirror wavefront aberration correction system is designed and established according to the optical properties of a membrane mirror. The LCSLM and a Hartmann-Shack sensor are used as a wavefront corrector and a wavefront detector, respectively. The detected wavefront aberration is calculated and converted into voltage value on LCSLM for the mirror wavefront aberration correction by programming in Matlab. When in experiment, the wavefront aberration of a glass plane mirror with a diameter of 70 mm is measured and corrected for verifying the feasibility of the experiment system and the correctness of the program. The PV value and RMS value of distorted wavefront are reduced and near diffraction limited optical performance is achieved. On this basis, the wavefront aberration of the aperture center Φ25 mm in a membrane mirror with a diameter of 200 mm is corrected and the errors are analyzed. It provides a means of correcting the wavefront aberration of membrane mirror.

The Thomson scattering system at Wendelstein 7-X

Science.gov (United States)

Pasch, E.; Beurskens, M. N. A.; Bozhenkov, S. A.; Fuchert, G.; Knauer, J.; Wolf, R. C.

2016-11-01

This paper describes the design of the Thomson scattering system at the Wendelstein 7-X stellarator. For the first operation campaign we installed a 10 spatial channel system to cover a radial half profile of the plasma cross section. The start-up system is based on one Nd:YAG laser with 10 Hz repetition frequency, one observation optics, five fiber bundles with one delay line each, and five interference filter polychromators with five spectral channels and silicon avalanche diodes as detectors. High dynamic range analog to digital converters with 14 bit, 1 GS/s are used to digitize the signals. The spectral calibration of the system was done using a pulsed super continuum laser together with a monochromator. For density calibration we used Raman scattering in nitrogen gas. Peaked temperature profiles and flat density profiles are observed in helium and hydrogen discharges.

Electrostatic polymer-based microdeformable mirror for adaptive optics

Science.gov (United States)

Zamkotsian, Frederic; Conedera, Veronique; Granier, Hugues; Liotard, Arnaud; Lanzoni, Patrick; Salvagnac, Ludovic; Fabre, Norbert; Camon, Henri

2007-02-01

Future adaptive optics (AO) systems require deformable mirrors with very challenging parameters, up to 250 000 actuators and inter-actuator spacing around 500 μm. MOEMS-based devices are promising for the development of a complete generation of new deformable mirrors. Our micro-deformable mirror (MDM) is based on an array of electrostatic actuators with attachments to a continuous mirror on top. The originality of our approach lies in the elaboration of layers made of polymer materials. Mirror layers and active actuators have been demonstrated. Based on the design of this actuator and our polymer process, realization of a complete polymer-MDM has been done using two process flows: the first involves exclusively polymer materials while the second uses SU8 polymer for structural layers and SiO II and sol-gel for sacrificial layers. The latest shows a better capability in order to produce completely released structures. The electrostatic force provides a non-linear actuation, while AO systems are based on linear matrices operations. Then, we have developed a dedicated 14-bit electronics in order to "linearize" the actuation, using a calibration and a sixth-order polynomial fitting strategy. The response is nearly perfect over our 3×3 MDM prototype with a standard deviation of 3.5 nm; the influence function of the central actuator has been measured. First evaluation on the cross non-linarities has also been studied on OKO mirror and a simple look-up table is sufficient for determining the location of each actuator whatever the locations of the neighbor actuators. Electrostatic MDM are particularly well suited for open-loop AO applications.

Geometry of mirror manifolds

International Nuclear Information System (INIS)

Aspinwall, P.S.; Luetken, C.A.

1991-01-01

We analyze the mirror manifold hypothesis in one and three dimensions using the simplest available representations of the N = 2 superconformal algebra. The symmetries of these tensor models can be divided out to give an explicit representation of the mirror, and we give a simple group theoretical algorithm for determining which symmetries should be used. We show that the mirror of a superconformal field theory does not always have a geometrical interpretation, but when it does, deformations of complex structure of one manifold are reflected in deformations of the Kaehler form of the mirror manifold, and we show how the large radius limit of a manifold corresponds to a large complex structure limit in the mirror manifold. The mirror of the Tian-Yau three generation model is constructed both as a conformal field theory and as an algebraic variety with Euler number six. The Hodge numbers of this manifolds are fixed, but the intersection numbes are highly ambiguous, presumably reflected a rich structure of multicritical points in the moduli space of the field theory. (orig.)

Resonant X-ray scattering in correlated systems