12,964 research outputs found
Multiple configuration shell-core structured robotic manipulator with interchangeable mechatronic joints : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Engineering in Mechatronics at Massey University, Turitea Campus, Palmerston North, New Zealand
With the increase of robotic technology utilised throughout industry, the need for skilled
labour in this area has increased also. As a result, education dealing with robotics has
grown at both the high-school and tertiary educational level. Despite the range of
pedagogical robots currently on the market, there seems to be a low variety of these
systems specifically related to the types of robotic manipulator arms popular for industrial
applications. Furthermore, a fixed-arm system is limited to only serve as an educational
supplement for that specific configuration and therefore cannot demonstrate more than
one of the numerous industrial-type robotic arms.
The Shell-Core structured robotic manipulator concept has been proposed to improve the
quality and variety of available pedagogical robotic arm systems on the market. This is
achieved by the reconfigurable nature of the concept, which incorporates shell and core
structural units to make the construction of at least 5 mainstream industrial arms
possible. The platform will be suitable, but not limited to use within the educational
robotics industry at high-school and higher educational levels and may appeal to
hobbyists.
Later dubbed SMILE (Smart Manipulator with Interchangeable Links and Effectors), the
system utilises core units to provide either rotational or linear actuation in a single plane.
A variety of shell units are then implemented as the body of the robotic arm, serving as
appropriate offsets to achieve the required configuration. A prototype consisting of a
limited number of ‘building blocks’ was developed for proof-of-concept, found capable of
achieving several of the proposed configurations.
The outcome of this research is encouraging, with a Massey patent search confirming the
unique features of the proposed concept. The prototype system is an economic, easy to
implement, plug and play, and multiple-configuration robotic manipulator, suitable for
various applications
Magnetometry with nitrogen-vacancy defects in diamond
The isolated electronic spin system of the Nitrogen-Vacancy (NV) centre in
diamond offers unique possibilities to be employed as a nanoscale sensor for
detection and imaging of weak magnetic fields. Magnetic imaging with nanometric
resolution and field detection capabilities in the nanotesla range are enabled
by the atomic-size and exceptionally long spin-coherence times of this
naturally occurring defect. The exciting perspectives that ensue from these
characteristics have triggered vivid experimental activities in the emerging
field of "NV magnetometry". It is the purpose of this article to review the
recent progress in high-sensitivity nanoscale NV magnetometry, generate an
overview of the most pertinent results of the last years and highlight
perspectives for future developments. We will present the physical principles
that allow for magnetic field detection with NV centres and discuss first
applications of NV magnetometers that have been demonstrated in the context of
nano magnetism, mesoscopic physics and the life sciences.Comment: Review article, 28 pages, 16 figure
The Equivalence of the Dekel-Fudenberg Iterative Procedure and Weakly Perfect Rationalizability
Two approaches have been proposed in the literature to refine the rationalizability solution concept: either assuming that players make small errors when playing their strategies, or assuming that there is a small amount of payoff uncertainty. We show that both approaches lead to the same refinement if errors are made according to the concept of weakly perfect rationalizability, and there is payoff uncertainty as in Dekel and Fudenberg [Journal of Economic Theory 52 (1990), 243-267]. For both cases, the strategies that survive are obtained by starting with one round of elimination of weakly dominated strategies followed by many rounds of elimination of strictly dominated strategies.Rationalizability, refinements
Magnetic-field-dependent photodynamics of single NV defects in diamond: Application to qualitative all-optical magnetic imaging
Magnetometry and magnetic imaging with nitrogen-vacancy (NV) defects in
diamond rely on the optical detection of electron spin resonance (ESR).
However, this technique is inherently limited to magnetic fields that are weak
enough to avoid electron spin mixing. Here we focus on the high off-axis
magnetic field regime for which spin mixing alters the NV defect spin dynamics.
We first study in a quantitative manner the dependence of the NV defect optical
properties on the magnetic field vector B. Magnetic-field-dependent
time-resolved photoluminescence (PL) measurements are compared to a seven-level
model of the NV defect that accounts for field-induced spin mixing. The model
reproduces the decreases in (i) ESR contrast, (ii) PL intensity and (iii)
excited level lifetime with an increasing off-axis magnetic field. We next
demonstrate that those effects can be used to perform all-optical magnetic
imaging in the high off-axis magnetic field regime. Using a scanning NV defect
microscope, we map the stray field of a magnetic hard disk through both PL and
fluorescence lifetime imaging. This all-optical method for high magnetic field
imaging at the nanoscale might be of interest in the field of nanomagnetism,
where samples producing fields in excess of several tens of milliteslas are
typical
Coherent population trapping of a single nuclear spin under ambient conditions
Coherent control of quantum systems has far-reaching implications in quantum
engineering. In this context, coherent population trapping (CPT) involving dark
resonances has played a prominent role, leading to a wealth of major
applications including laser cooling of atoms and molecules, optical
magnetometry, light storage and highly precise atomic clocks. Extending CPT
methods to individual solid-state quantum systems has been only achieved in
cryogenic environments for electron spin impurities and superconducting
circuits. Here, we demonstrate efficient CPT of a single nuclear spin in a room
temperature solid. To this end, we make use of a three-level system with a
-configuration in the microwave domain, which consists of nuclear spin
states addressed through their hyperfine coupling to the electron spin of a
single nitrogen-vacancy defect in diamond. Dark state pumping requires a
relaxation mechanism which, in atomic systems, is simply provided by
spontaneous emission. In this work, the relaxation process is externally
controlled through incoherent optical pumping and separated in time from
consecutive coherent microwave excitations of the nuclear spin
-system. Such a pumping scheme with controlled relaxation allows us
(i) to monitor the sequential accumulation of population into the dark state
and (ii) to reach a new regime of CPT dynamics for which periodic arrays of
dark resonances can be observed, owing to multiple constructive interferences.
This work offers new prospects for quantum state preparation, information
storage in hybrid quantum systems and metrology.Comment: 13 pages including supplementary information, links to figures
correcte
Coherent population trapping of a single nuclear spin under ambient conditions
Coherent control of quantum systems has far-reaching implications in quantum
engineering. In this context, coherent population trapping (CPT) involving dark
resonances has played a prominent role, leading to a wealth of major
applications including laser cooling of atoms and molecules, optical
magnetometry, light storage and highly precise atomic clocks. Extending CPT
methods to individual solid-state quantum systems has been only achieved in
cryogenic environments for electron spin impurities and superconducting
circuits. Here, we demonstrate efficient CPT of a single nuclear spin in a room
temperature solid. To this end, we make use of a three-level system with a
-configuration in the microwave domain, which consists of nuclear spin
states addressed through their hyperfine coupling to the electron spin of a
single nitrogen-vacancy defect in diamond. Dark state pumping requires a
relaxation mechanism which, in atomic systems, is simply provided by
spontaneous emission. In this work, the relaxation process is externally
controlled through incoherent optical pumping and separated in time from
consecutive coherent microwave excitations of the nuclear spin
-system. Such a pumping scheme with controlled relaxation allows us
(i) to monitor the sequential accumulation of population into the dark state
and (ii) to reach a new regime of CPT dynamics for which periodic arrays of
dark resonances can be observed, owing to multiple constructive interferences.
This work offers new prospects for quantum state preparation, information
storage in hybrid quantum systems and metrology.Comment: 13 pages including supplementary information, links to figures
correcte
Measuring the magnetic moment density in patterned ultrathin ferromagnets with submicron resolution
We present a new approach to infer the surface density of magnetic moments
in ultrathin ferromagnetic films with perpendicular anisotropy. It relies
on quantitative stray field measurements with an atomic-size magnetometer based
on the nitrogen-vacancy center in diamond. The method is applied to
microstructures patterned in a 1-nm-thick film of CoFeB. We report measurements
of with a few percent uncertainty and a spatial resolution in the range
of nm), an improvement by several orders of magnitude over existing
methods. As an example of application, we measure the modifications of
induced by local irradiation with He ions in an ultrathin ferromagnetic
wire. This method offers a new route to study variations of magnetic properties
at the nanoscale.Comment: 9 pages and 7 figures including main text and Supplemental
Informatio
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