1,182 research outputs found
Research on Keyhole Diameterβs Vision Measurement Based on Parallel Technology
A keyhole diameter of the cartridgeβs measurement based on machine vision is a part of the cartridgeβs geometry measurement system, according to the system requirements, to complete the measurement within 5 seconds. A Image Collection System was constructed using computer, CCD camera, LED source, meanwhile a measurement system was compiled by C# on VS2010 platform based on machine vision. Use the Otsu algorithm to extracts the keyholeβs edge and near the pixels in order to reduce the computational Canny operator, and use parallel computing in the Canny operator to improve computing speed purposes. Use QueryPerformanceCounter timer for each module timing Canny operator, Canny operator improved computation time is reduced from the original 6s to nearly a hundred ms improved. Meet the time requirements of cartridge geometry measurement system, and other machine vision in which the project can be widely used
Anthriscifolcine A, a C18-diterpenoid alkaloid
The title compound, C26H39NO7, which was isolated from Delphinium anthriscifolium var. majus, has a lycoctonine carbon skeleton containing four six-membered rings (A, B, D and E) and three five-membered rings (C, F and G). Rings A, B and E adopt chair conformation, while ring D adopts a boat conformation. Rings C and F adopt envelope conformations
More on volume dependence of spectral weight function
Spectral weight functions are easily obtained from two-point correlation
functions and they might be used to distinguish single-particle from
multi-particle states in a finite-volume lattice calculation, a problem crucial
for many lattice QCD simulations. In previous studies, it is shown that the
spectral weight function for a broad resonance shares the typical volume
dependence of a two-particle scattering state i.e. proportional to in a
large cubic box of size while the narrow resonance case requires further
investigation. In this paper, a generalized formula is found for the spectral
weight function which incorporates both narrow and broad resonance cases.
Within L\"uscher's formalism, it is shown that the volume dependence of the
spectral weight function exhibits a single-particle behavior for a extremely
narrow resonance and a two-particle behavior for a broad resonance. The
corresponding formulas for both and channels are derived. The
potential application of these formulas in the extraction of resonance
parameters are also discussed
Radiative transitions in charmonium from twisted mass lattice QCD
We present a study for charmonium radiative transitions:
, and
using twisted mass lattice QCD gauge
configurations. The single-quark vector form factors for and
are also determined. The simulation is performed at a lattice
spacing of fm and the lattice size is . After
extrapolation of lattice data at nonzero to 0, we compare our results
with previous quenched lattice results and the available experimental values.Comment: typeset with revtex, 15 pages, 11 figures, 4 table
TMRT observations of 26 pulsars at 8.6 GHz
Integrated pulse profiles at 8.6~GHz obtained with the Shanghai Tian Ma Radio
Telescope (TMRT) are presented for a sample of 26 pulsars. Mean flux densities
and pulse width parameters of these pulsars are estimated. For eleven pulsars
these are the first high-frequency observations and for a further four, our
observations have a better signal-to-noise ratio than previous observations.
For one (PSR J0742-2822) the 8.6~GHz profiles differs from previously observed
profiles. A comparison of 19 profiles with those at other frequencies shows
that in nine cases the separation between the outmost leading and trailing
components decreases with frequency, roughly in agreement with
radius-to-frequency mapping, whereas in the other ten the separation is nearly
constant. Different spectral indices of profile components lead to the
variation of integrated pulse profile shapes with frequency. In seven pulsars
with multi-component profiles, the spectral indices of the central components
are steeper than those of the outer components. For the 12 pulsars with
multi-component profiles in the high-frequency sample, we estimate the core
width using gaussian fitting and discuss the width-period relationship.Comment: 33 pages, 49 figures, 5 Tables; accepted by Ap
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