This study develops a flexible strain sensor with electromagnetic interference(EMI)shielding,hydrophobicity,and acid/alkali resistance by integrating a bi-ordered porous structure with a micro-raised surface.The struc...This study develops a flexible strain sensor with electromagnetic interference(EMI)shielding,hydrophobicity,and acid/alkali resistance by integrating a bi-ordered porous structure with a micro-raised surface.The structure,mimicking lotus leaves,is fabricated using magnetic field-assisted freezing orientation and laser ablation on graphene(Gr)/Fe nanowire(NW)-infused aerogel and polydimethylsiloxane.The sensor,with a Gr to Fe NW ratio of 9:1,shows a high gauge factor of 85.19 in the 0–30%tensile strain.These values are 304%,430%,702%,and 1226%of the samples with Gr to Fe NWs ratios of 7:1,5:1,3:1,and 1:1,respectively.It achieves an EMI shielding efficiency(SE)of 20.02 dB and a specific SE of 807.48 dB cm^(2)/g in the 8.2–12.4 GHz range,150%higher than isotropic samples.The sensor exhibits a contact angle of 155.76°,maintaining hydrophobic stability under stretching and showing excellent resistance to acid and alkali.Additionally,the sensor can be integrated into wearable devices like gloves for gesture recognition,machine hand manipulation,and controlling neon bulbs,demonstrating potential for applications in field robotics and human-robot interaction.展开更多
Unified and extended splines(UE-splines), which unify and extend polynomial, trigonometric, and hyperbolic B-splines, inherit most properties of B-splines and have some advantages over B-splines. The interest of this ...Unified and extended splines(UE-splines), which unify and extend polynomial, trigonometric, and hyperbolic B-splines, inherit most properties of B-splines and have some advantages over B-splines. The interest of this paper is the degree elevation algorithm of UE-spline curves and its geometric meaning. Our main idea is to elevate the degree of UE-spline curves one knot interval by one knot interval. First, we construct a new class of basis functions, called bi-order UE-spline basis functions which are defined by the integral definition of splines.Then some important properties of bi-order UE-splines are given, especially for the transformation formulae of the basis functions before and after inserting a knot into the knot vector. Finally, we prove that the degree elevation of UE-spline curves can be interpreted as a process of corner cutting on the control polygons, just as in the manner of B-splines. This degree elevation algorithm possesses strong geometric intuition.展开更多
基金supported by the Chongqing New Youth Innovation Talent Program(Grant No.CSTB2024NSCQ-QCXMX0086)National Natural Science Foundation of China(Grant No.52205589)+4 种基金Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K202300606)Natural Science Foundation of Anhui Province(Grant No.2208085QE141)China Postdoctoral Science Foundation(Grant Nos.2023T160765,2022MD713695)Young Elite Scientists Sponsorship Program by CAST(China Association for Science and Technology)(Grant No.2022QNRC001)Hong Kong Scholars Program。
文摘This study develops a flexible strain sensor with electromagnetic interference(EMI)shielding,hydrophobicity,and acid/alkali resistance by integrating a bi-ordered porous structure with a micro-raised surface.The structure,mimicking lotus leaves,is fabricated using magnetic field-assisted freezing orientation and laser ablation on graphene(Gr)/Fe nanowire(NW)-infused aerogel and polydimethylsiloxane.The sensor,with a Gr to Fe NW ratio of 9:1,shows a high gauge factor of 85.19 in the 0–30%tensile strain.These values are 304%,430%,702%,and 1226%of the samples with Gr to Fe NWs ratios of 7:1,5:1,3:1,and 1:1,respectively.It achieves an EMI shielding efficiency(SE)of 20.02 dB and a specific SE of 807.48 dB cm^(2)/g in the 8.2–12.4 GHz range,150%higher than isotropic samples.The sensor exhibits a contact angle of 155.76°,maintaining hydrophobic stability under stretching and showing excellent resistance to acid and alkali.Additionally,the sensor can be integrated into wearable devices like gloves for gesture recognition,machine hand manipulation,and controlling neon bulbs,demonstrating potential for applications in field robotics and human-robot interaction.
基金Project supported by the National Natural Science Foundation of China(Nos.60933008 and 61272300)
文摘Unified and extended splines(UE-splines), which unify and extend polynomial, trigonometric, and hyperbolic B-splines, inherit most properties of B-splines and have some advantages over B-splines. The interest of this paper is the degree elevation algorithm of UE-spline curves and its geometric meaning. Our main idea is to elevate the degree of UE-spline curves one knot interval by one knot interval. First, we construct a new class of basis functions, called bi-order UE-spline basis functions which are defined by the integral definition of splines.Then some important properties of bi-order UE-splines are given, especially for the transformation formulae of the basis functions before and after inserting a knot into the knot vector. Finally, we prove that the degree elevation of UE-spline curves can be interpreted as a process of corner cutting on the control polygons, just as in the manner of B-splines. This degree elevation algorithm possesses strong geometric intuition.
