ASIC for High-Speed-Gating and Free Running Operation of SPADs

Single photon detection at telecom wavelengths is of importance in many industrial applications ranging from quantum cryptography, quantum optics, optical time domain reflectometry, non-invasive testing of VLSI circuits, eye-safe LIDAR to laser ranging. In practical applications, the combination of an InGaAs/InP APD with an appropriate electronic circuit still stands as the best solution in comparison with emerging technologies such as superconducting single photon detectors, MCP-PMTs for the near IR or up-conversion technique. An ASIC dedicated to the operation of InGaAs/InP APDs in both gated mode and free-running mode is presented. The 1.6mm2 chip is fabricated in a CMOS technology. It combines a gate generator, a voltage limiter, a fast comparator, a precise timing circuit for the gate signal processing and an output stage. A pulse amplitude of up to +7V can be achieved, which allows the operation of commercially available APDs at a single photon detection probability larger than 25% at 1.55μm. The avalanche quenching process is extremely fast, thus reducing the afterpulsing effects. The packaging of the diode in close proximity with the quenching circuit enables high speed gating at frequencies larger than 10MHz. The reduced connection lengths combined with impedance adaptation technique provide excellent gate quality, free of oscillations or bumps. The excess bias voltage is thus constant over the gate width leading to a stable single photon detection probability and timing resolution. The CMOS integration guarantees long-term stability, reliability and compactness

New method of Chitosan spinning: application to reinforcing plate

Advances in Chitin Science, Proceedings of the 6th International Conference of the European Chitin Society, Volume VIII, p214-219, H. Struszczyk , A. Domard, M.G. Peter, H. Pospieszny Eds, Institute of Plant Protection, Poznan, ISBN 83-89867-25-

Morphology and mechanical properties of chitosan fibers obtained by gel-spinning: Influence of the dry-jet-stretching step and ageing

International audienc

New method of Chitosan spinning: application to reinforcing plate

Advances in Chitin Science, Proceedings of the 6th International Conference of the European Chitin Society, Volume VIII, p214-219, H. Struszczyk , A. Domard, M.G. Peter, H. Pospieszny Eds, Institute of Plant Protection, Poznan, ISBN 83-89867-25-

Polyelectrolyte microstructure in chitosan aqueous and alcoholic solutions

International audienceThis work deals with chain ordering in aqueous and water−alcohol solutions of chitosan. The so-called polyelectrolyte peak is investigated by small-angle synchrotron X-ray scattering. The polyelectrolyte microstructure was characterized by the position of the maximum of the polyelectrolyte scattering peak qmax, which scales with the polymer concentration cp as qmax cpα. An evolution of the power law exponent α is observed as a function of the degree of acetylation (DA) of chitosan, which is responsible for changes of both the charge density (f) and the hydrophobicity of the polymer chains. The results highlighted the two organization regimes of the theory of Dobrynin and Rubinstein,1 investigated here for the first time for a natural polymer. At low DAs, α ≈ 1/2, in agreement with a pearl necklace organization where the structure is controlled by the string between pearls. For higher DA, α ≈ 1/3, and the correlation revealed by the polyelectrolyte peak is controlled by the pearls. This analysis offers a way to study quantitatively the balance between solvophobic−solvophilic interactions that play an important role in the solution properties of natural polymers. In addition, the role of several parameters acting on the interaction balance were evidenced, such as the nature of the counterion, the composition of the solvent (amount of alcohol in the aqueous solution), and the screening of Coulombic forces by salt addition. Finally, the nanostructure transition from a polyelectrolyte solution to a physical gel is discussed. The gel state is reached when the solvophobic interactions are favored, but depending on the gelation route the polyelectrolyte ordering could be preserved or not

Ordering in Bio-Polyelectrolyte Chitosan Solutions

International audienc

Chitosan Physical Hydrogels: a new therapeutic way to burn injuries treatment., in Advances in Chitin Science, Volume VIII, 193-198

Proceedings of the 6th International Conference of the European Chitin Society, EUCHIS '4Advances in Chitin Science, vol VIII, 193-198, ISBN 83-89867-25-7,H. Struszczyk , A. Domard, M.G. Peter, H. Pospieszny Eds, Poznan 2005

Chitosan Physical Hydrogels: a new therapeutic way to burn injuries treatment., in Advances in Chitin Science, Volume VIII, 193-198

Proceedings of the 6th International Conference of the European Chitin Society, EUCHIS '4Advances in Chitin Science, vol VIII, 193-198, ISBN 83-89867-25-7,H. Struszczyk , A. Domard, M.G. Peter, H. Pospieszny Eds, Poznan 2005

Microwave-Assisted Chemical Ablation (MA-CA): A Novel Microwave-Assisted Tissue Ablation Procedure—Preliminary Assessment of Efficiency

Microwave (MW) ablation is becoming a routine technology in the interventional radiology field. A new approach combining MW ablation and chemical ablation is developed in this paper. The rationale for the development of this Microwave-Assisted Chemical Ablation (MA-CA) technology was to improve the utility of thermal ablation as a minimally invasive treatment for cancer. The experimental conditions for ex vivo bovine liver samples were: A—100 W (120 s) with no addition of ethanol; B—100 W (30 s), wait (60 s) (no power), and 100 W (90 s) with no addition of ethanol; C—100 W (30 s), wait (60 s), 100 W (30 s), and 100 W (60 s) with the addition of 5 mL ethanol; and D—100 W (30 s), wait (60 s), 100 W (30 s), 0 W (30 s) with the addition of 2.5 mL ethanol, and 100 W (60 s) with the addition of 5 mL ethanol (12,000 Joules Total). The results showed that with the use of ethanol, the ablation zone was enlarged and revealed improved sphericity. This novel combination has greater advantages than either technology individually. The objective is to increase the precision and efficiency of MW ablation and to broaden the range of tissues and pathologies that can be treated using this new approach, and to validate the benefits that arise from combining the advantages of MW and chemical ablation in a relevant setting