Search results for "VCS"

Mesure de la section efficace de l'électroproduction de photons à JLAB dans le but d'effectuer une Séparation Rosenbluth de la contribution DVCS

2014

The study of the inner structure of hadrons allows us to understand the nature of the interactions between partons, quarks and gluons, described by Quantum Chromodynamics. The elastic scattering reactions, which have been studied in order to measure the nucleon form factors, are included in this frame. The inelastic scattering reactions are also included in this frame, they allow us to obtain information about the nucleon structure thanks to the development of the parton distribution functions (PDFs). While through elastic scattering we can obtain information about the charge distribution of the nucleon, and hence, about the spatial distribution of the partons, through inelastic scattering …

Electrical and optical low frequency noises in multimodal vertical cavity surface emitting lasers

2006

Experimental investigations of the low frequency noise of multimode 780 nm vertical cavity surface emitting lasers are reported. Electrical noise, optical noise and their correlation have been measured in the frequency range 1 Hz–95 kHz. The results show that the main contribution to the electrical noise is located in the distributed Bragg reflector layers of the laser. The optical power and pump current noise sources are strongly correlated below and around the threshold, while are weakly correlated above threshold. It is argued that the noise in the optical power is due to both free injection carrier noise and optical gain fluctuations.

Coherence functions of the electrical and the optical noises in monomodal packaged vertical cavity surface emitting lasers

2006

Calculations of the frequency noise spectra and of the coherence functions between the electrical and the optical noises for a single-mode packaged vertical surface emitting laser (VCSEL) are reported.A rate-equation model for an index guided VCSEL is used, implemented with the electrical noise model including the intrinsic device, the package and external bias network.The extended model works up to the laser relaxation frequency. The amplitude optical noise and its correlation with the frequency and electrical noises are also analysed. The influence on the calculated quantities of some electrical and laser parameters is evaluated. The results show that generally the frequency noise is corr…

New Insight in the $Q^2$-Dependence of Proton Generalized Polarizabilities

2019

Virtual Compton scattering on the proton has been investigated at three yet unexplored values of the four-momentum transfer $Q^2$: 0.10, 0.20 and 0.45 GeV$^2$, at the Mainz Microtron. Fits performed using either the low-energy theorem or dispersion relations allowed the extraction of the structure functions $P_{LL} -P_{TT} / \epsilon$ and $P_{LT}$, as well as the electric and magnetic generalized polarizabilities $\alpha_{E1}(Q^2)$ and $\beta_{M1}(Q^2)$. These new results show a smooth and rapid fall-off of $\alpha_{E1}(Q^2)$, in contrast to previous measurements at $Q^2$ = 0.33 GeV$^2$, and provide for the first time a precise mapping of $\beta_{M1}(Q^2)$ in the low-$Q^2$ region.

1.3 µm GaInNAs optically-pumped vertical cavity semiconductor optical amplifier

2003

A GaInNAs/GaAs vertical cavity semiconductor optical amplifier (VCSOA) is reported. This is believed to be the first monolithic VCSOA operating at 1.3 mum. Under continuous-wave optical pumping in a singlemode fibre coupled format, gain figures of up to 17.7 dB were achieved. Amplification with 12 GHz bandwidth,was obtained at 12.8 dB peak gain.

LightCycler Septifast® and VCS: Relationship Between Two Innovative Instruments in Severe Sepsis and Septic Shock

2009

VCS: a Cheap and Fast Parameter for Early Diagnosis of Severe Sepsis and Septic Shock

2010

GaInNAs VCSEL structure as a modelocking element for a 1.3 µm Nd:YVO4 laser

2001

1.3 µm GaInNAs monolithic vertical-cavity semiconductor optical amplifier

2003

Evaluation of automated hematologic VCS parameters in severe sepsis and septic shock: a case-control study.

2010

A cheap and quick hematologic diagnostic parameter for detection of sepsis would have both economic and therapeutic benefits. The Coulter LH series hematology analyzer uses the VCS technology (Volume, Conductivity, Laser Scatter) providing information about cell volume, size, internal structure, and surface morphology. Many authors analyzed the clinical usefulness of VCS parameters in reactive neutrophils for detection of sepsis. An increase in mean cell volume and a decrease in mean light scatter in septic patients have been described. Our aim is to verify the correlation between VCS parameters and sepsis.