1,545 research outputs found
The HeH Reaction with Full Final--State Interaction
An {\it ab initio} calculation of the HeH longitudinal
response is presented. The use of the integral transform method with a Lorentz
kernel has allowed to take into account the full four--body final state
interaction (FSI). The semirealistic nucleon-nucleon potential MTI--III and the
Coulomb force are the only ingredients of the calculation. The reliability of
the direct knock--out hypothesis is discussed both in parallel and in non
parallel kinematics. In the former case it is found that lower missing momenta
and higher momentum transfers are preferable to minimize effects beyond the
plane wave impulse approximation (PWIA). Also for non parallel kinematics the
role of antisymmetrization and final state interaction become very important
with increasing missing momentum, raising doubts about the possibility of
extracting momentum distributions and spectroscopic factors. The comparison
with experimental results in parallel kinematics, where the Rosenbluth
separation has been possible, is discussed.Comment: 17 pages, 5 figure
Development of a New Parallel Kinematics Machine Tool
Development of the computer techniques has made possible the application
of a new machine tool
construction, the parallel kinematics. Hexapod robots can be used in
several fields of the
manufacturing and robotics. On the TU Budapest, Department of Manufacturing
Engineering, we
have developed a new 3 leg-parallel kinematics machine tool, we described
the mathematical model
of the kinematics, and completed the design necessary for the production.
This
paper gives summary about the parallel kinematics and our development
activity
Design and Properties of Octaslide Redundant Parallel Kinematics
This paper describes the conceptual design process of OCTASLIDE redundant parallel kinematics for a machine tool. Redundantly actuated parallel kinematics is a recently developed new concept for machine tools. It enables all mechanical properties of machine tools to be improved several times simultaneously. This is particularly demonstrated on the design of the OCTASLIDE. This is a concept of a five-axis machine tool centre. The paper describes the critical initial design phases and the accessible mechanical properties. The design process has follow the newly developed design methodology for parallel kinematics machines
Measuring longitudinal amplitudes for electroproduction of pseudoscalar mesons using recoil polarization in parallel kinematics
We propose a new method for measuring longitudinal amplitudes for
electroproduction of pseudoscalar mesons that exploits a symmetry relation for
polarization observables in parallel kinematics. This polarization technique
does not require variation of electron scattering kinematics and avoids the
major sources of systematic errors in Rosenbluth separation.Comment: intended for Phys. Rev. C as a Brief Repor
Вільна система ЧПУ для верстата паралельної структури
Application of LinuxCNC (open-source Linux based CNC software) to control parallel kinematic machine tools is considered. A control architecture and configuration files developed for LinuxCNC parallel kinematics machine tool with Stewart platform. Розглянуто використання вільної системи ЧПУ LinuxCNC з відкритим кодом для управління верстатами паралельної структури. Запропоновано структурну схему та файли конфігурації системи управління, використаної для верстата паралельної структури на основі платформи Стюарта
Study of Concepts of Parallel Kinematics Machines for Advanced Manufacturing
This paper deals with possible new concepts for machine tools based on parallel kinematics for advanced manufacturing. Parallel kinematics machines (PKM) enable the mechanical properties of manufacturing machines to be improved. This has been proven by several new machine tool concepts. However, this potential can be and must be increased by applying the principle of redundant actuation. This paper deals with the extension of the concepts of redundantly actuated parallel kinematics structures for five-sided five-axis machine tools and for a free-forming sheet metal forming machine. The design principles of previous successful PKMs are summarized and new concepts are proposed. The most important requirement criteria are summarized. The proposed concepts are qualitatively and initially quantitatively evaluated according to these criteria.
Quasi-elastic polarization-transfer measurements on the deuteron in anti-parallel kinematics
We present measurements of the polarization-transfer components in the
H reaction, covering a previously unexplored kinematic
region with large positive (anti-parallel) missing momentum, , up
to 220 MeV, and . These measurements, performed
at the Mainz Microtron (MAMI), were motivated by theoretical calculations which
predict small final-state interaction (FSI) effects in these kinematics, making
them favorable for searching for medium modifications of bound nucleons in
nuclei. We find in this kinematic region that the measured
polarization-transfer components and and their ratio agree with the
theoretical calculations, which use free-proton form factors. Using this, we
establish upper limits on possible medium effects that modify the bound
proton's form factor ratio at the level of a few percent. We also
compare the measured polarization-transfer components and their ratio for H
to those of a free (moving) proton. We find that the universal behavior of
H, He and C in the double ratio
is maintained in the positive
missing-momentum region
Correlated Strength in Nuclear Spectral Function
We have carried out an (e,e'p) experiment at high momentum transfer and in
parallel kinematics to measure the strength of the nuclear spectral function
S(k,E) at high nucleon momenta k and large removal energies E. This strength is
related to the presence of short-range and tensor correlations, and was known
hitherto only indirectly and with considerable uncertainty from the lack of
strength in the independent-particle region. This experiment confirms by direct
measurement the correlated strength predicted by theory.Comment: 4 pages, 2 figures, accepted by Phys. Rev. Let
- …