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Avian feather is the outstanding protein fiber structure that still lacks an interpretation generally acceptable in any detail. In this paper, asio otus feathers were morphological represented and their barbs were mechanical characterized by a developed micro-tensile tester with a load resolution of 0.25 mN and a displacement resolution of 10 nm. With a tensile loading speed at 0.02 μm/s, Young’s modulus of the flight feather barbs with length of 1450-1900 μm was calculated to be 3.13-3.66 GPa, higher than 1.47-2.04 GPa for the down feather barbs with length of 520-710 μm. It is concluded that the asio otus’s flight feathers on its wing and tail are more rigid than the down feathers on its body.

Wood-polymer composite was prepared by a novel combined two-step method with maleic anhydride (MAN) for the first treatment, and mixed monomers of glycidyl methacrylate (GMA)/ methyl methacrylate (MMA) (1:5 of molar ratio) for the second treatment. SEM and FTIR technologies were employed to characterize the interfacial compatibility between resultant polymer and wood matrix, and the dimensional stability of the resultant wood-polymer composite was also tested. The results indicated that polymers fully filled up wood cell lumina and chemically bonded to wood cell wall, resulting in the improvement of interfacial compatibility between polymer and wood matrix without obvious lacunae. The dimensional stability of poplar wood was significantly improved after the combined two-step treatment, and became more stable than that of PEG-1000 treated Poplar Wood.

Fe/Cu nanometer-scale multilayers with nominal modulation wavelengths ranging from 5 to 40 nm are deposited by direct current magnetron sputtering on Si (100) substrates. Modulation structures of the multilayers are examined by small angle / wide angle x-ray diffraction (SA/WAXRD) and cross-sectional transmission electron microscopy (XTEM). Hardness of the multilayers is measured by using nanoindentation. All the multilayers have Fe (110) and Cu (111) textures. Interface coherency is observed in the multilayers with designed modulation wavelengths of 5 and 10 nm. The hardness increases firstly and then deceases with increasing the modulation wavelength, and reaches peak value of 7.29±0.29 GPa in the multilayers with nominal modulation wavelength of 10 nm. The evolution of the hardness of the mulitlayers is explained by interface width and modulus difference between sublayers.

SU-8 is not only an epoxy-based negative-tone photoresist but also a potential building structural material which can be directly used as movable parts in micro structures for its unique UV curing characters and high-aspect ratio. It is particularly suitable for the fabrication of a wide range of low-temperature processes objects, such as micro valves, micro gear wheels and micro grippers. A standard mechanical property parameter database of SU-8 in microscale has not been established while its characters can vary significantly depending on the process conditions. The Young's modulus is one of the important parameters to evaluate the mechanical properties of this novel structural material, especially for the optimum design, performance realization and reliability analysis of micro devices. This paper presents the design of free-standing SU-8 thin film specimens with different sizes. The fabrication processing is demonstrated and the Young's modulus is achieved through tensile testing. The experiments are operated on a micro-tensile testing system. The force is measured by a load cell with accuracy of 0.25 mN and elongation of specimen is obtained from a displacement sensor with accuracy of 0.1 um. The measured Young's modulus of 60um wide SU-8 specimens from force-displacement curves is about 2.2±0.1 GPa. The behavior of plastic deformation is also detected before elastic deformation during the experimental process.

This work presents the mechanical characterization of SU-8 photoresists studied in the form of microscaled free-standing thin films with various effective length/width (aspect) ratios, achieved by a tensile testing method. Specimens were designed with gauge segments measuring 240 to 540 μm long and 40 to 80 μm wide with thickness fixed at 20 μm, all fabricated in the same processing conditions. The experiments were carried out on a microtensile testing system which had a load and displacement resolution of 0.25 mN and 10 nm, respectively. With a tensile loading speed of 0.02 μm/s, the average fracture strength of SU-8 photoresist was measured to be 66.34 MPa, and the calculated Young's modulus ranged from 0.86 to 2.33 GPa and the maximum strain from 1.02% to 9.70%, with variation dependent on the effective aspect ratio of the tested films. As a result, effective aspect ratio is concluded to be a significant factor mechanically charactering the size effect of SU-8 photoresist in microscale.