A Scalable, Self-Analyzing Digital Locking System for use on Quantum Optics Experiments

Digital control of optics experiments has many advantages over analog control systems, specifically in terms of scalability, cost, flexibility, and the integration of system information into one location. We present a digital control system, freely available for download online, specifically designed for quantum optics experiments that allows for automatic and sequential re-locking of optical components. We show how the inbuilt locking analysis tools, including a white-noise network analyzer, can be used to help optimize individual locks, and verify the long term stability of the digital system. Finally, we present an example of the benefits of digital locking for quantum optics by applying the code to a specific experiment used to characterize optical Schrodinger cat states.Comment: 7 pages, 5 figure

Corrosion in MEA units for CO2 capture: Pilot plant studies

AbstractAmong the technologies that are under study for CO2 capture from flue gas, the separation process using monoethanolamine (MEA) could be the first to be available for immediate industrial applications in the next few years. The principles of CO2 separation using alkanolamines were discovered nearly a century ago. The process has been applied successfully for several decades in areas such as natural gas processing or coal gasification. The application to flue gas treatment was introduced in the early 1980s, but was not widespread.In such industrial processes, corrosion represents one of the major operational problems. For the capture of CO2 from flue gas using MEA, the problem is even more critical since (i) MEA is one of the most corrosive amine when compared to secondary or tertiary amines that are also used for gas sweetening, and (ii) flue gas contains a certain amount of oxygen, which can react with the amine to form corrosive degradation products.In the framework of the CAPRICE project, which is an International cooperation and exchange project supported by the EU, The International Test centre for CO2 Capture from the University of Regina (CA) and IFP (F) have shared their experience on corrosion monitoring from CO2 capture pilot plants. The first pilot plant facility is owned by ITC. It has a capacity to capture 1 ton CO2/day from a natural gas burner. It is equipped with corrosion control instruments and other monitoring systems. The second pilot plant is located in a coal fired power station in Esbjerg (DK). It was built with the financial support of the UE through the CASTOR project under the lead of IFP. It has been in operation since early 2006, and has a capacity of 1.0 ton CO2/hour. It is equipped with weight loss coupons for corrosion evaluation at different locations in the process.This paper presents the major results of corrosion testing from both pilot plants under MEA operation. It appeared from both pilot plants that the areas most susceptible to corrosion were the stripper inlet and outlet, with corrosion rates around 1 mm.year−1 for carbon steel

Damping of optomechanical disks resonators vibrating in air

We report on miniature GaAs disk optomechanical resonators vibrating in air in the radiofrequency range. The flexural modes of the disks are studied by scanning electron microscopy and optical interferometry, and correctly modeled with the elasticity theory for annular plates. The mechanical damping is systematically measured, and confronted with original analytical models for air damping. Formulas are derived that correctly reproduce both the mechanical modes and the damping behavior, and can serve as design tools for optomechanical applications in fluidic environment

Electrostatic vibration energy harvester using multimodal-shaped springs for pacemaker application

International audienceThis paper presents an innovative broadband electrostatic vibration energy harvester (eVEH) using miniaturized multimodal-shaped nonlinear springs for powering an autonomous pacemaker. The presented bioMEMS device has been designed for acceleration levels in the range of 1 g or lower, and a high frequency bandwidth in low frequency domain that allows harvesting of a real heartbeat excitation. An extensive study of the response of the device as a function of the heartbeat rate, the acceleration amplitude and its inclination with respect to the gravity field is performed. It is demonstrated that the presented device, with overall volume < 0.3 cm3, delivers up to 2.38 μW neat average power under real heartbeat excitation conditions with 10 m/s2 acceleration amplitude at 116 bpm. The harvester is using the Multimodal-shaped springs, which allow to construct the mechanical nonlinearity required for sensitive wideband device in a precise way while keeping the whole system sufficiently miniaturized. The device is fabricated with dedicated clean room process on silicon-on-glass (SoG) wafer. © 2018 IEEE

Forming Weakly Interacting Multilayers of Graphene Using Atomic Force Microscope Tip Scanning and Evidence of Competition between Inner and Outer Raman Scattering Processes Piloted by Structural Defects

[EN] We report on an alternative route based on nanomechanical folding induced by an AFM tip to obtain weakly interacting multilayer graphene (wi-MLG) from a chemical vapor deposition (CVD)-grown single-layer graphene (SLG). The tip first cuts and then pushes and folds graphene during zigzag movements. The pushed graphene has been analyzed using various Raman microscopy plots- AD/ AG × EL4 vs ΓG, ω2D vs Γ2D, Γ2D vs ΓG, ω2D+/- vs Γ2D+/-, and A2D-/ A2D+ vs A2D/ AG. We show that the SLG in-plane properties are maintained under the folding process and that a few tens of graphene layers are stacked, with a limited number of structural defects. A blue shift of about 20 cm-1 of the 2D band is observed. The relative intensity of the 2D- and 2D+ bands have been related to structural defects, giving evidence of their role in the inner and outer processes at play close to the Dirac cone.Funding by the Spanish Ministerio de Economía y Competitividad under Project MAT2015-65356-C3-1-R is acknowledged. French PACA Region is acknowledge

Forming Weakly Interacting Multilayers of Graphene Using Atomic Force Microscope Tip Scanning and Evidence of Competition between Inner and Outer Raman Scattering Processes Piloted by Structural Defects

International audienceWe report on an alternative route based on nanomechanical folding induced by an AFM tip to obtain weakly interacting multilayer graphene (wi-MLG) from a chemical vapor deposition (CVD)-grown single-layer graphene (SLG). The tip first cuts and then pushes and folds graphene during zigzag movements. The pushed graphene has been analyzed using various Raman microscopy plotsA D /A G × E L 4 vs Γ G , ω 2D vs Γ 2D , Γ 2D vs Γ G , ω 2D+/− vs Γ 2D+/− , and A 2D− /A 2D+ vs A 2D /A G. We show that the SLG in-plane properties are maintained under the folding process and that a few tens of graphene layers are stacked, with a limited number of structural defects. A blue shift of about 20 cm − 1 of the 2D band is observed. The relative intensity of the 2D − and 2D + bands have been related to structural defects, giving evidence of their role in the inner and outer processes at play close to the Dirac cone