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In-situ SEM nanoindentation and nanoscratch testing methods are commonly used for mechanical characterization and investigation of the deformation and failure mechanisms of coating materials with micro-to nano-scale thicknesses. However, existing SEM-based integrated nanoindentation and nanoscratch instruments have two main limitations. First, the measured mechanical properties of the coating materials at micro-to nano-scale thicknesses are highly sensitive to surface roughness. Second, the existing SEM-based instruments lack the capability to acquire the morphology of residual imprints in real-time after nanoindentation and nanoscratching. In this study, a novel SEM-based integrated nanoindentation, nanoscratch, and atomic force microscopy (AFM) instrument, namely, NMT-AFM was proposed, developed and fabricated. The self-sensing piezoresistive cantilever (PRC) was selected as the AFM force sensor owing to its miniaturization ability. However, the resistance of the PRC sensor fluctuated because of the electron irradiation from SEM, resulting in the continuous drift of the PRC signal during SEM imaging. To overcome this limitation, a mechanism of PRC signal drift inside SEM was analyzed for the first time, and a PRC signal drift reduction method was proposed based on the mechanism analysis. The experimental results indicated that the PRC signal drift was reduced to 2 nm in 2 min by applied external voltage value UA of 30 V to modified PRC, which proved the proposed mechanism of PRC signal drift during SEM imaging. Finally, the X–Y fine nanopositioner angle calibration test using AFM calibration chip VGRP-UM and the nanoindentation/nanoscratch characterizations of the TiAlSiN coating material were conducted.

Nanopositioning stage, based on the stick–slip principle, is a hot research topic due to its unparallel merits such as compact structure, high resolution, and long travel stroke. However, most of the conventional stick–slip nanopositioning stages only have the ability to move along the horizontal directions. In addition, analysis of vertical stage movement is few. This paper proposes a novel stick–slip nanopositioning stage capable of moving upwards and downwards with an excellent performance. An adjusting unit was developed and integrated into the stage to effectively change friction force which is the key to the vertical stage movement. Theoretical and numerical analysis show that many parameters including revised driving signal contributes to the upward movement of stick–slip nanopositioning stage. Experimental results show that the stage has the capability of traveling up to 22 mm with an upward positioning accuracy of 7.00 nm and a downward positioning accuracy of 5.00 nm, respectively. The maximum speed for maximum speeds of stage for upward and downward motion were measured to be 2.70 and 0.77 mm/s, respectively. The maximum load of stage in vertical direction is 72 g. This stage design has a huge potential in applications requiring vertical manipulation while requiring nanometer positioning accuracies, high travel stroke, compact structure, and large load.

Instrumented indentation test inside SEM has become a versatile method for nanomechanical characterization and studying of deformation and failure mechanisms of coating materials at nano-to micro-scale thickness. However, the existing SEM-based nanoindentation instrument cannot acquire surface roughness of coating materials at nano-to micro-scale thickness before nanoindentation and the morphology of residual imprints in real-time inside SEM after nanoindentation. To overcome those two limitations, a new SEM-based nanoindentation instrument integrated with AFM function has been developed. This paper presents a miniature piezoresistive transducer capable of measuring force up to ±2.5N with a resolution of 0.5μN, and measuring displacement up to ±36μm with a resolution of 0.01nm for new developed SEM-based nanoindentation instrument. The transducer design, optimization, readout electronics and characterization are described. Cross-shape compliant mechanism is adopted considering the influence of the lateral force during nanoindentation process. Moreover, four piezoresistive bar-type semiconductor strain gauges (SCSG) have been glued on the cross-shape compliant mechanism enabling the transducer has a compact structure. A new temperature compensation method for SCSG sensors is proposed and solves the problem of amplifier saturation compared with traditional temperature compensation method. Compared with the existing widely used capacitive-based transducer for instrumented indentation test inside SEM, cross-shape piezoresistive transducer shows larger measured ranges. Compared with the existing piezoresistive-based transducer for instrumented indentation test inside SEM, cross-shape piezoresistive transducer shows better resolutions. In the end, the validation test of AFM imaging inside HITACHI SU5000 using standard AFM calibration chip SiC/0.75 is tested.

International audience; Nitrogen (N) and Phosphorus (P) losses from rural landscapes are of major concern as they can cause eutrophication of inland and coastal waters. Spatial management of landscape features distribution is sometimes proposed as a viable solution to limit nutrient transfer to streams and rivers. However, the effectiveness of such measures is rarely quantified at the catchment scale. We propose a spatially explicit data analysis to assess whether the spatial distribution of nutrient sources in agricultural landscapes influences nitrate and total phosphorus (TP) exports.We sampled water in 19 independent headwater catchments (1 to 14 km²) every two weeks for 18 months and analyzed nitrate and TP. The headwaters studied were located within the same 375 km² catchment and they had similar soil type, climate and farming systems but their landscapes differ in their composition (i.e. percentage of agricultural land) and distribution (i.e. agricultural land distance to ditches/streams & degree of overlay with flow accumulation zones). The method consisted in comparing a model only accounting for the land use composition (lumped) with a spatially explicit index that weights agricultural land according to its spatial distribution. We derived a hydrological distance to the stream (HDS) map, and a flow accumulation map (FAcc) from a 10m resolution digital elevation model. We aggregated land-use, HDS and FAcc maps within a catchment-level metric defined as Σ(LU*FAcc^a / HDS^b), where LU takes the value of 1 for agricultural land use and 0 for other land-uses. The parameters a and b were calibrated against median concentration of TP and nitrate, with the objective of maximizing the correlation on ranks.Results showed that median nitrate concentrations depended largely on landscape composition whereas the landscape distribution had a great influence on TP exports. From the optimal values of a and b we showed that both distance to the stream and overlay with flow accumulation influence TP exports. Our research provides useful insights to design new landscape management strategies.