Neutral particle Mass Spectrometry with Nanomechanical Systems

Current approaches to Mass Spectrometry (MS) require ionization of the analytes of interest. For high-mass species, the resulting charge state distribution can be complex and difficult to interpret correctly. In this article, using a setup comprising both conventional time-of-flight MS (TOF-MS) and Nano-Electro-Mechanical-Systems-based MS (NEMS-MS) in situ, we show directly that NEMS-MS analysis is insensitive to charge state: the spectrum consists of a single peak whatever the species charge state, making it significantly clearer than existing MS analysis. In subsequent tests, all charged particles are electrostatically removed from the beam, and unlike TOF-MS, NEMS-MS can still measure masses. This demonstrates the possibility to measure mass spectra for neutral particles. Thus, it is possible to envisage MS-based studies of analytes that are incompatible with current ionization techniques and the way is now open for the development of cutting edge system architectures with unique analytical capability

High Frequency top-down Junction-less Silicon Nanowire Resonators

We report here the first realization of top-down silicon nanowires (SiNW) transduced by both junction-less field effect transistor (FET) and the piezoresistive (PZR) effect. The suspended SiNWs are among the smallest top-down SiNWs reported to date, featuring widths down to ~20nm. This has been achieved thanks to a 200mm-wafer-scale, VLSI process fully amenable to monolithic CMOS co-integration. Thanks to the very small dimensions, the conductance of the silicon nanowire can be controlled by a nearby electrostatic gate. Both the junction-less FET and the previously demonstrated PZR transduction have been performed with the same SiNW. These self-transducing schemes have shown similar signal-to-background ratios, and the PZR transduction has exhibited a relatively higher output signal. Allan deviation AD of the same SiNW has been measured with both schemes, and we obtain AD~20ppm for the FET detection and AD~3ppm for the PZR detection at room temperature and low pressure. Orders of magnitude improvements are expected from tighter electrostatic control via changes in geometry and doping level, as well as from CMOS integration. The compact, simple topology of these elementary SiNW resonators opens up new paths towards ultra-dense arrays for gas and mass sensing, time keeping or logic switching systems in SiNW-CMOS platform

Strain Measurements During Structural Conservation Treatment and the Long-term Monitoring of a 17th-century Dutch Panel Painting

No abstract available

Strain Measurements During Structural Conservation Treatment and the Long-term Monitoring of a 17th-century Dutch Panel Painting

No abstract available

Image Correlation to Evaluate the Influence of Hygrothermal Loading on Wood

International audienceMany wooden objects from cultural heritage consist in wooden panels, painted on one face. Some of these panels show permanent cupping, micro-cracks of the painted layer, and cracks of the painted support itself. Different physical and mechanical phenomena are at the origin of these damages: wood is a hygroscopic material (its dimensions vary with humidity), it is highly anisotropic, the paint layer on one face has properties of permeability different from those of raw wood of the back face, and a rigid frame possibly restrained the deformation of the panel. Experimentations on our mock-up panels combined with numerical simulations of these panels in real situations of hygrothermal fluctuations will allow us to test specific situations and eventually to make suggestions to conservators and restorers and guide them in their interventions. Hygrothermal treatments are often used to improve wood durability thanks a reduction of its hygroscopicity. They have been considered as means to reproduce the physical properties of ancient wood. We intend to model the mechanisms involved in mechanical and chemical effects of wooden painted panels exposed to climatic variations. To develop such conservation tool, we need to work on mock-up, which replicate panel painting. So we will investigate the process of hygroscopic ageing and compression set generation of the back of painted panels to explain their permanent cupping and replicate their ageing state. For this purpose, digital image correlation is used to evaluate the strain field of the section of a wood piece submitted to variations of relative humidity

Étude expérimentale et numérique du comportement hygromécanique d'un panneau de bois: Application à la conservation des tableaux peints sur bois du patrimoine

National audienc

Étude expérimentale et numérique du comportement hygromécanique d’un panneau de bois. Application à la conservation des tableaux peints sur bois du patrimoine

No abstract available

Étude expérimentale et numérique du comportement hygromécanique d’un panneau de bois. Application à la conservation des tableaux peints sur bois du patrimoine

No abstract available

Characterisation and modelling of nonlinear resonance behaviour on very-high-frequency silicon nanoelectromechanical resonators

This paper reports a novel method to build a model for nonlinear resonance behaviour of very-high-frequency (VHF) silicon nanoelectromechanical (NEM) resonators, measured via 1-ω mixing resonance measurements. Systematic fitting results for the experimental data of a 1.5-μm-long beams have been achieved with explicit explanation of the amount of intrinsic mechanical nonlinearity and nonlinear voltage-tuning effect. Asymmetric line shape and onset of hysteresis on nonliner resonance behavour have been well demonstrated with less fitting errors. The development of a modelling method of nanoscale resonator devices which includes nonlinear response is beneficial for seamless technology transfer from individual devices to integrated systems in the future