tissues could be organized into a helical assembly, [4][5][6] showing remarkable photonic properties and attractive structural anisotropy. The advantages of cellulosic sustainability and biocompatibility make it superior to other photonic materials to produce optical materials. Bioinspired cellulose's multiscale architecture has implemented a series of photonic building blocks, mainly including hydroxypropyl cellulose, [7] ethylcellulose, [8] and cellulose nanocrystal (CNC). [9,10] Among them, the self-assembly of CNCs into chiral photonic structures is the most representative. An artistic view (Figure 1a) shows a solid film formed by the selfassembly of CNCs, which is similar to the Bouligand structure of the beetle exoskeleton. [11,12] CNCs consist of each chain of β-(poly-1,4-D-glucose) stabilized via hydrogen bonds and hydrophobic interactions that provide mechanical stiffness to the solid film. [13] CNC-derived photonic materials have spawned a series of exciting applications in the fields of sensors, [14,15] optics, [16,17] electronics, [18] and engineering. [19,20] However, in many cases, the above materials rarely undergo elastic deformation but crack in bending, thus compromising their outstanding properties. In addition, the photonic structures of these materials are incompatible with humid and liquid environments because of their high hygroscopicity and water solubility.Cellulose nanocrystals (CNCs)-derived photonic materials have confirmed great potential in producing renewable optical and engineering areas. However, it remains challenging to simultaneously possess toughness, strength, and multi ple responses for developing high-performance sensors, intelligent coatings, flexible textiles, and multifunctional devices. Herein, the authors report a facile and robust strategy that poly(ethylene glycol) dimethacrylate (PEGDMA) can be converged into the chiral nematic structure of CNCs by ultraviolet-triggered free radical polymerization in an N,N-dimethylformamide solvent system. The resulting CNC-poly(PEGDMA) composite exhibits impressive strength (42 MPa), stretchability (104%), toughness (31 MJ m −3 ), and solvent resistance. Notably, it preserves vivid optical iridescence, displaying stretchable variation from red, yellow, to green responding to the applied mechanical stimuli. More interestingly, upon exposure to spraying moisture, it executes sensitive actuation (4.6° s −1 ) and multiple complex 3D deformation behaviors, accompanied by synergistic iridescent appearances. Due to its structural anisotropy of CNC with typical left-handedness, the actuation shows the capability to generate a high probability (63%) of right-handed helical shapes, mimicking a coiled tendril. The authors envision that this versatile system with sustainability, robustness, mechanochromism, and specific actuating ability will open a sustainable avenue in mechanical sensors, stretchable optics, intelligent actuators, and soft robots.The ORCID identification number(s) for the author(s) of this article can be found under https:/...

High-performance graphene-based transistors crucially depend on the creation of the high-quality graphene-metal contacts. Here we report an approach for achieving ultralow contact resistance simply with optical lithography by engineering a metal-graphene interface. Note that a significant improvement with optical lithography for the contact-treated graphene device leads to a contact resistance as low as 150 Ω·μm. The residue-free sacrificial film impedes the photoresist from further doping graphene, and all of the source and drain contact regions defined by optical lithography remain intact. This approach, being compatible with complementary metal-oxide-semiconductor (CMOS) fabrication processes regardless of the source of graphene, would hold promise for the large-scale production of graphene-based transistors with optical lithography.

Experimental and numerical investigations were carried out to study the average cooling performance of two different rectangular structures: 1) purely ribbed channel (only ribs were periodically embedded inner the wall of the structure); 2) combined structure of film cooling with the ribs (in the ribbed wall, film holes were periodically drilled). To create a similar environment of gas turbine blade, the experiments were performed at a high temperature mainstream, and the ambient temperature cooling air passed through the channel with the direction normal to the mainstream. In the experimental and numerical investigations, the overall cooling effect contributed by the heat conduction through channel’s wall and convections including internal ribbed wall and external film cooling was considered. In the numerical investigation, 3D conservation equations including mass, momentum, energy, turbulence eddy frequency and turbulence kinetic energy equations were solved with ANSYS-CFX, and the hybrid mesh technique and shear stress transport (SST) k-ω model were adopted. This numerical approach was validated by the experimental data. Using the validated numerical approach, the influence factors on the overall cooling effectiveness are discussed, and the effects of the internal ribs and external film cooling are numerically compared by the two structures. The relationship of the overall cooling effectiveness averaged over the rectangular surface with the mainstream Reynolds number, mass flow ratio and temperature ratio of the mainstream to cooling air, as well as the blowing ratio injected through the film holes was fitted by the numerical results.

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All the existing constitutive relationships are only corresponding to a special hardness and will be inapplicable when the hardness changes. Therefore, the constitutive relationship that is based on the J-C model and that considers hardness is presented in this paper through considering the influence of hardness on yield strength and tensile strength. The constitutive relationship that considers hardness is built for AISI 4340 steel and the comparison with experimental results shows that this model can correctly express the material's dynamic mechanical performance at different hardness