Search results for "Polarization"
showing 10 items of 1884 documents
Photoinduced Electron Transfer in a Porphyrin-Fullerene Dyad at a Liquid Interface
2022
The excited-state properties of an amphiphilic porphyrin–fullerene dyad and of its porphyrin analogue adsorbed at the dodecane/water interface are investigated by using surface second-harmonic generation. Although the porphyrin is formally centrosymmetric, the second-harmonic spectra of both compounds are dominated by the intense Soret band of the porphyrin. Polarization-selective measurements and molecular dynamics simulations suggest an angle of about 45° between the donor–acceptor axis and the interfacial plane, with the porphyrin interacting mostly with the nonpolar phase. Time-resolved measurements reveal a marked concentration dependence of the dynamics of both compounds upon Q-band e…
All polarization-maintaining assively mode-locked yb-doped fiber laser : pulse compression using an anomalous polarization-maintaining photonic cryst…
2019
We report the generation of short pulses at 1 μm using an all-polarization-maintaining (PM) fiber configuration. The pulses are provided by an all normal-dispersion Fabry-Perot Yb-doped cavity and are compressed with an anomalous polarization-maintaining photonic crystal fiber (PM PCF). Opposed to standard configurations; here the filtering action is solely performed by the finite bandwidth of the gain medium. The laser generates 8 ps width sech 2 profile pulses at 1046.8 nm with a −10 dB bandwidth of 5.9 nm. After compression using the PM PCF, pulses with an FWHM of 3 ps were obtained, limited by the actual value of the available anomalous dispersion. We also report the changes in the outp…
All-Fiber Laser With Intracavity Acousto-Optic Dynamic Mode Converter for Efficient Generation of Radially Polarized Cylindrical Vector Beams
2017
We report an all-fiber laser that emits a radially polarized cylindrical vector beam (CVB) at 1 μm based on an intracavity acousto-optic mode converter. We efficiently generate the CVB, taking advantage of the acousto-optic coupling from the HE11 mode to the TM01 mode in a two-mode fiber. The laser can be switched from emitting a Gaussian-like beam to a radially polarized CVB. Radially polarized CVBs with modal and polarization purities >98% and a maximum power of 65 mW were generated.
Time evolution of medium and long-period ground tilting at Campi Flegrei caldera
2020
Abstract. We analyse tiltmeter time series recorded from April 2015 to March 2019 at three borehole instruments installed at Campi Flegrei caldera (Italy). We evaluate the crustal response in terms of ground tilting to external excitations of medium/long-period tidal constituents by applying a polarization analysis. The azimuths of the tilt vectors show well-defined polarization directions and the ground tilting planes oscillate with the periodicity of the corresponding tidal constituents. For two of the three tiltmeters, the average ground oscillation pattern related to the monthly Mm and fortnightly Mf constituents show seasonal variations, which can be ascribed to rainfall-induced tiltin…
Failure Rate Measurement on Silicon Diodes Reverse Polarized at High Temperature
2017
This paper calculates the failure rate on reversed polarized silicon diodes with the aim to justify, experimentally, the rules of the European Space Agency (ESA) which are referred to the component life’s extension, the reliability increase and the end of life performance enhancement, by using oversized devices (derating rules). In order to verify the derating rules, 80 silicon diodes are used, which are reverse polarized in a high temperature environment. The diodes are divided in 4 groups of 20 diodes, applying a different voltage to each group, in order to relate the failure rate to the applied derating rule. The experiment described in this paper is developed using a temperature acceler…
Tumor-Infiltrating γδ T Lymphocytes: Pathogenic Role, Clinical Significance, and Differential Programing in the Tumor Microenvironment.
2014
There is increasing clinical evidence indicating that the immune system may either promote or inhibit tumor progression. Several studies have demonstrated that tumors undergoing remission are largely infiltrated by T lymphocytes [tumor-infiltrating lymphocytes (TILs)], but on the other hand, several studies have shown that tumors may be infiltrated by TILs endowed with suppressive features, suggesting that TILs are rather associated with tumor progression and unfavorable prognosis. γδ T lymphocytes are an important component of TILs that may contribute to tumor immunosurveillance, as also suggested by promising reports from several small phase-I clinical trials. Typically, γδ T lymphocytes …
Resonance in Interacting Induced-Dipole Polarizing Force Fields: Application to Force-Field Derivatives
2009
The Silberstein model of the molecular polarizability of diatomic molecules, generalized by Applequist et al. for polyatomic molecules, is analyzed. The atoms are regarded as isotropically polarizable points located at their nuclei, interacting via the fields of their induced dipoles. The use of additive values for atom polarizabilities gives poor results, in some cases leading to artificial predictions of absorption bands. The molecular polarizability of methane and its derivative are computed. The agreement with experimental mean molecular polarizabilities is within 1–5%. A hypothesis is indispensable for a suitable representation of polarizability derivative.
Outlying location of logistics activities : the example of the Burgundy in France
2015
International audience; This paper contributes to the understanding of spatial location of logistics activities in an outlying region. A quantitative analysis in Burgundy (French region) underlines the important polarization of warehousing developed in a limited area during 1980–1990s intensified during 2000s. The companies that locate their warehouses in Burgundy have different strategies that could explain this outlying location. For example, the low cost of land, favorable terms of tax system and the presence of a labour pool with an important unemployed rate incentive could incentive some companies to locate their warehouses in an outlying region like the Burgundy.
Rosenbluth separation of the $\pi^0$ Electroproduction Cross Section off the Neutron
2017
We report the first longitudinal/transverse separation of the deeply virtual exclusive $\pi^0$ electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions $d\sigma_L/dt$, $d\sigma_T/dt$, $d\sigma_{LT}/dt$ and $d\sigma_{TT}/dt$ are extracted as a function of the momentum transfer to the recoil system at $Q^2$=1.75 GeV$^2$ and $x_B$=0.36. The $ed \to ed\pi^0$ cross sections are found compatible with the small values expected from theoretical models. The $en \to en\pi^0$ cross sections show a dominance from the response to transversely polarized photons, and are in good agreement with calculations based on the transversity GPDs of the nucle…
Magnetoelectric effects in superconductor/ferromagnet bilayers
2018
We demonstrate that the hybrid structures consisting of a superconducting layer with an adjacent spin-textured ferromagnet demonstrate the variety of equilibrium magnetoelectric effects originating from coupling between the conduction electron spin and superconducting current. By deriving and solving the generalized Usadel equation which takes into account the spin-filtering effect we find that a supercurrent generates spin polarization in the superconducting film which is non-coplanar with the local ferromagnetic moment. The inverse magnetoelectric effect in such structures is shown to result in the spontaneous phase difference across the magnetic topological defects such as a domain wall …