2,815 research outputs found
Cytoplasmic contribution to protoperithecium formation
Cytoplasmic contribution to protoperithecium formatio
Quantitative Rescattering Theory for high-order harmonic generation from molecules
The Quantitative Rescattering Theory (QRS) for high-order harmonic generation
(HHG) by intense laser pulses is presented. According to the QRS, HHG spectra
can be expressed as a product of a returning electron wave packet and the
photo-recombination differential cross section of the {\em laser-free}
continuum electron back to the initial bound state. We show that the shape of
the returning electron wave packet is determined mostly by the laser only. The
returning electron wave packets can be obtained from the strong-field
approximation or from the solution of the time-dependent Schr\"odinger equation
(TDSE) for a reference atom. The validity of the QRS is carefully examined by
checking against accurate results for both harmonic magnitude and phase from
the solution of the TDSE for atomic targets within the single active electron
approximation. Combining with accurate transition dipoles obtained from
state-of-the-art molecular photoionization calculations, we further show that
available experimental measurements for HHG from partially aligned molecules
can be explained by the QRS. Our results show that quantitative description of
the HHG from aligned molecules has become possible. Since infrared lasers of
pulse durations of a few femtoseconds are easily available in the laboratory,
they may be used for dynamic imaging of a transient molecule with femtosecond
temporal resolutions.Comment: 50 pages, 15 figure
Technique for removing resin from a molded object
Resin is removed from a molded object in such a way that no cracks or expansion occurs in the casting. The resin is first mixed with a ceramics powder or metal powder. This mixture is then molded and the resin is removed by heat. The molded object is then placed into a container which is sealed and large enough to allow the gas from the resin to be controlled by heat from the resin. The gas pressure at the surface of the object is increased by the gas pressure generated from the resin and the resin removed. The increase in gas pressure from the surface of the molded object is 1.5 atm to 3 atm at 350 C to 400 C
A New Approach for Assessing Kinematics of Torso Twist in Baseball Batting: A Preliminary Report
The motions of segments involved in striking and throwing events are generally sequenced in a proximal-to-distal fashion (Putnam 1993). Welch et al. (1995) analyzed baseball batting using a rigid-body-link model with a two-segment torso, and indicated the importance that the lower torso starts rotation in the direction of pitcher before the upper torso, which, in turn, should start before the arm segments. Also, this sequential motion is considered to allow the kinetic link system to generate synergy between the musculature of the torso and upper extremity. Specifically, the upper torso is expected to have an important function to accelerate distal upper extremity and bat. However previous studies employed a two-segment torso model and the influence of the motions of the shoulder-girdles to the torso’s sequential action for twisting was ignored. In the present study, torso’s sequential twisting was analyzed with a three-segment torso model, and the kinematics of torso twist in baseball batting was evaluated
Potential for ultrafast dynamic chemical imaging with few-cycle infrared lasers
We studied the photoelectron spectra generated by an intense few-cycle
infrared laser pulse. By focusing on the angular distributions of the back
rescattered high energy photoelectrons, we show that accurate differential
elastic scattering cross sections of the target ion by free electrons can be
extracted. Since the incident direction and the energy of the free electrons
can be easily changed by manipulating the laser's polarization, intensity, and
wavelength, these extracted elastic scattering cross sections, in combination
with more advanced inversion algorithms, may be used to reconstruct the
effective single-scattering potential of the molecule, thus opening up the
possibility of using few-cycle infrared lasers as powerful table-top tools for
imaging chemical and biological transformations, with the desired unprecedented
temporal and spatial resolutions.Comment: 16 pages, 6 figure
Critical evaluation of attosecond time delays retrieved from photoelectron streaking measurements
Citation: Wei, H., Morishita, T., & Lin, C. D. (2016). Critical evaluation of attosecond time delays retrieved from photoelectron streaking measurements. Physical Review A - Atomic, Molecular, and Optical Physics, 93(5). doi:10.1103/PhysRevA.93.053412A photoelectron streaking experiment which was conceived as a means to extract the electron wave packet of single-photon ionization has also been employed to retrieve time delays in the fundamental photoemission processes. The discrepancies between the time delays thus measured and those from many sophisticated theoretical calculations have generated a great deal of controversy in recent years. Here we present a careful examination of the methods that were used to retrieve the time delays and demonstrate the difficulty of achieving an accuracy of the retrieved time delays of a few to tens of attoseconds in typical streaking measurements. The difficulty owes more to the lower sensitivity of the streaking spectra to the phase of the photoionization transition dipole than to the spectral phase of the attosecond light pulse in the experiment. The retrieved time delay contains extra errors when the attochirp of the attosecond pulse is large so that the dipole phase becomes negligible compared to it. © 2016 American Physical Society
Observation of Root Rot and Internal Breakdown of Redclover (\u3ci\u3eTrifolium pratense\u3c/i\u3e L.) in the 3rd Year
Two red clover (Trifolium pratense L.) cultivars; Hokuseki and Merviot were surveyed growth habits and deterioration at the crown and taproot in the 3rd year. Each cutting plants were marked and measured the plant height and dry matter weight. After 3rd cutting of the 3rd year, plants were digged out and scored the degree of root rot and internal break down (no symptom: 0-severe damaged: 5). The severe damaged plants at the 3rd cutting tend to have larger plant size at the 1st cutting. And other root development traits during growth were observed
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