- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - In-situ Microscopy Characterization of Cu(In,Ga)Se <sub/>2</sub> Potential-Induced Degradation
摘要： During irradiation UO2 nuclear fuel experiences the development of a non-uniform distribution of porosity which contributes to establish varying mechanical properties along the radius of the pellet. Radial variations of both porosity and elastic properties in high burnup UO2 pellet can be investigated via high frequency acoustic microscopy. For this purpose ultrasound waves are generated by a piezoelectric transducer and focused on the sample, after having travelled through a coupling liquid. The elastic properties of the material are related to the velocity of the generated Rayleigh surface wave (VR). A UO2 pellet with a burnup of 67 GWd/tU was characterized using the acoustic microscope installed in the hot cells of the JRC-ITU at a 90 MHz frequency, with methanol as coupling liquid. VR was measured at different radial positions. A good agreement was found, when comparing the porosity values obtained via acoustic microscopy with those determined using SEM image analysis, especially in the areas close to the centre. In addition, Young’s modulus was calculated and its radial pro?le was correlated to the corresponding burnup pro?le and to the hardness radial pro?le data obtained by Vickers micro-indentation
关键词： Nuclear fuels,piezoelectric devices,Vickers microhardness,Young’s modulus,nuclear power
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Rough and Straightforward Estimation of the Mismatching Loss by Partial Shading of the PV Modules Installed on an Urban Area or Car-Roof
摘要： During irradiation UO2 nuclear fuel experiences the development of a non-uniform distribution of porosity which contributes to establish varying mechanical properties along the radius of the pellet. Radial variations of both porosity and elastic properties in high burnup UO2 pellet can be investigated via high frequency acoustic microscopy. For this purpose ultrasound waves are generated by a piezoelectric transducer and focused on the sample, after having travelled through a coupling liquid. The elastic properties of the material are related to the velocity of the generated Rayleigh surface wave (VR). A UO2 pellet with a burnup of 67 GWd/tU was characterized using the acoustic microscope installed in the hot cells of the JRC-ITU at a 90 MHz frequency, with methanol as coupling liquid. VR was measured at different radial positions. A good agreement was found, when comparing the porosity values obtained via acoustic microscopy with those determined using SEM image analysis, especially in the areas close to the centre. In addition, Young’s modulus was calculated and its radial pro?le was correlated to the corresponding burnup pro?le and to the hardness radial pro?le data obtained by Vickers micro-indentation
关键词： Nuclear fuels,piezoelectric devices,Vickers microhardness,Young’s modulus,nuclear power
更新于2025-09-19 17:13:59
-
Ultrasound-assisted electrodeposition of Fe-Ni film for OLED mask
摘要： Fe-Ni alloy is considered as the most suitable metal for OLED mask making due to its excellent properties. However, electrodeposited Fe-Ni ?lm is often companied with poor surface quality and thermal expansion. To get proper ?lm for masks making, experiments of electroforming Fe–Ni were performed with di?erent ultrasonic powers and current densities. Results show that Fe-Ni ?lm with smooth surface could be electrodeposited at high current density due to the reducing of internal stress of ?lm by ultrasonic power. The iron content, grain size, micro-hardness and Young’s modulus of ?lm all present an upward trend with ultrasonic power increases from 13 W to 93 W, and then a downward trend due to the intensively transient cavitation caused by higher ultrasonic power 120 W. With the ultrasonic power of 93 W and current density of 1 A/dm2, a good surface quality of Fe-Ni ?lms with 60.07 wt.% iron content, microhardness 351 HV, Young's modulus 167.5 GPa and CTE 3.38 × 10?6/℃ can be electrodeposited.
关键词： Fe-Ni ?lm,Electroforming,Young's modulus,Ultrasonic power,Thermal expansion
更新于2025-09-19 17:13:59
-
The Elastic Property of Bulk Silicon Nanomaterials through an Atomic Simulation Method
摘要： This paper reports a systematic study on the elastic property of bulk silicon nanomaterials using the atomic finite element method. The Tersoff-Brenner potential is used to describe the interaction between silicon atoms, and the atomic finite element method is constructed in a computational scheme similar to the continuum finite element method. Young’s modulus and Poisson ratio are calculated for [100], [110], and [111] silicon nanowires that are treated as three-dimensional structures. It is found that the nanowire possesses the lowest Young’s modulus along the [100] direction, while the [110] nanowire has the highest value with the same radius. The bending deformation of [100] silicon nanowire is also modeled, and the bending stiffness is calculated.
关键词： atomic finite element method,silicon nanowires,Poisson ratio,elastic property,bending stiffness,Young’s modulus
更新于2025-09-10 09:29:36
-
Properties of ta-C coatings prepared by pulsed cathodic arc source at various distances
摘要： Tetrahedral amorphous carbon (ta-C) coatings have been prepared on silicon substrates by the pulsed cathodic arc source. For the limitation of the heat flux of the carbon plasma to the sample, the diaphragm of 27 mm diameter has been used. The deposition process has been carried out at three different distances between the arc source and the substrate: 150, 215 and 265 mm. The properties of ta-C coatings have been studied by Raman spectroscopy and dynamic nanoindentation techniques. The analysis of Raman spectra parameters has revealed that the concentration of ordered aromatic rings in Csp2 cluster decreases with distance between the arc source and the substrate while the concentration of chain groups increases. Nanoindentation has shown the decrease in nanohardness and Young's modulus with the distance. Nanohardness value falls from 21 GPa to 16 GPa and Young's modulus value goes down from 197 GPa to 177 GPa. So, it’s possible to control the formation of ta-C coatings structure by changing distance between the pulsed cathodic arc source and the substrate.
关键词： ta-C coatings,nanohardness,Young's modulus,pulsed cathodic arc source,nanoindentation,Raman spectroscopy
更新于2025-09-09 09:28:46
-
Young’s Modulus of Fullerene C <sub/>60</sub> –C <sub/>70</sub> Alloy Crystalline Nanowhiskers
摘要： Crystalline nanowhiskers (NWs) composed of fullerene C60 and C70 molecules, i.e., alloy NWs, were synthesized by a liquid–liquid interfacial precipitation method. The nominal composition of C70 ranged from 0 to 40 mass%. The bending tests of the alloy NWs were performed inside a high-resolution transmission electron microscope, and the deformation behavior was observed in situ. The bending force acting on the NWs were measured simultaneously by an optical deflection method, and the Young’s modulus was estimated from the resulting force–flexure curves. The average Young’s modulus was found to increase to approximately 30 GPa as the C70 composition was increased to the solubility limit. In contrast, the Young’s modulus decreased with increasing NW diameter caused by the addition of C70.
关键词： Fullerene,Bending,Young’s Modulus,Transmission Electron Microscopy,Nanowhisker
更新于2025-09-09 09:28:46
-
Stress control of tensile-strained In <sub/>1?</sub><sub/><i>x</i> </sub> Ga <sub/><i>x</i> </sub> P nanomechanical string resonators
摘要： We investigate the mechanical properties of freely suspended nanostrings fabricated from tensile-stressed, crystalline In1?xGaxP. The intrinsic strain arises during epitaxial growth as a consequence of the lattice mismatch between the thin film and the substrate, and is confirmed by x-ray diffraction measurements. The flexural eigenfrequencies of the nanomechanical string resonators reveal an orientation dependent stress with a maximum value of 650 MPa. The angular dependence is explained by a combination of anisotropic Young’s modulus and a change of elastic properties caused by defects. As a function of the crystal orientation, a stress variation of up to 50% is observed. This enables fine tuning of the tensile stress for any given Ga content x, which implies interesting prospects for the study of high Q nanomechanical systems.
关键词： In1?xGaxP,tensile-strained,defects,nanomechanical string resonators,Young’s modulus,stress control
更新于2025-09-09 09:28:46
-
Nanoindentation of circular multilayer graphene allotropes
摘要： Nanoindentaion has been proposed as an efficient technique to measure mechanical single-layer two-dimensional (2D) materials via combining the membrane theory with the indentation data. However, for multilayered structures of 2D materials, significant discrepancy exists between the Young’s modulus obtained from the existing membrane model and those from other methods. Here we develop a multilayer indentation model by taking the multilayer effect into account in the previous membrane model. We show that the present model can accurately predict the Young’s modulus of multilayered 2D carbon materials. For few layer graphene and twin graphene structures, the deviation of the Young’s moduli obtained by the present model are both within a reasonable range, while the error caused by the direct use of the previous single-layer membrane model increases with the number of layers. The present model provides an efficient tool to extract the mechanical properties of 2D materials from the nanoindentation data of their multilayered structures.
关键词： Young’s modulus,two-dimensional materials,nanoindentaion,molecular dynamics
更新于2025-09-04 15:30:14