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We demonstrate a low-cost and facile photochemical solution method to prepare the ZrO resistive switching arrays as memristive units on flexible PET/ITO substrates. ZrO solution sensitive to UV light of 337 nm was synthesized using zirconium n-butyl alcohol as the precursor, and benzoylacetone as the complexing agent. After the dip-coated ZrO gel films were irradiated through a mask under the UV lamp (with wavelength of 325-365 nm) at room temperature and rinsed in ethanol, the ZrO gel arrays were obtained on PET/ITO substrates. Subsequently, the ZrO gel arrays were irradiated by deep UV light of 254 and 185 nm at 150 °C, resulting in the amorphous ZrO memristive micro-arrays. The ZrO units on flexible PET/ITO substrates exhibited excellent memristive properties. A high ratio of 10 of on-state and off-state resistance was obtained. The resistive switching behavior of the flexible device remained stable after being bent for 10 times. The device showed stable flexibility up to a minimum bending diameter of 1.25 cm.

Superconducting YBa 2 Cu 3 O 7-x (YBCO) films were prepared using an ultralow-fluorine sol with F/Ba = 2, which was synthesized using fluorine-contained barium trifluoroacetate (Ba-TFA), and fluorine-free yttium, barium, and copper salts. The mole ratio of F/Ba = 2 was realized in the sol by controlling the content of Ba-TFA. During the pyrolysis process, the fluorine-free and fluorine-contained Ba-salts were found to be completely converted to BaF 2 phase, and almost no corrosive fluorinated gases (such as HF gas) were released out of the film, resulting in the film with smooth surface even under a high heating rate of 10-15°C/min. Single-coated YBCO film (*280 nm) with critical current density (J c ) of 5 MA/cm 2 (77 K, 0 T), and double-coated film (*550 nm) with J c over 3.5 MA/cm 2 (77 K, 0 T) were obtained on LaAlO 3 single crystal substrates. Compared with YBCO films deposited from solutions with higher fluorine content, the ultralow-fluorine solgel deposited YBCO films showed comparable superconductivity, but improved surface quality and production rate.

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In this paper, based on the finite element method, the stresses of the radius and ulna are analyzed at different flexion angles of the elbow when playing tennis. The finite element model is presented for the elbow position with flexion angles of 0°, 25°, 60°, and 80° according to the normal human arm bone. In this model, the whole arm with metacarpals, radius, ulna, humerus and scapula is considered. The calculation is simplified by setting the scapula and metacarpals as rigid bodies and using Tie binding constraints between the humerus and the radius and ulna. This model is discretized using the 10-node second-order tetrahedral element (C3D10). This model contains 109,765 nodes and 68,075 elements. The hitting forces applied to the metacarpal bone are 100 N and 300 N, respectively. The numerical results show that the highest principal stresses are at the points of 1/4 of the radius, the elbow joint, and the points of 1/10 of the ulna. The results of the maximum principal stress show that the external pressures are more pronounced as the elbow flexion angle increases and that the magnitude of the hitting force does not affect the principal stress distribution pattern. Elbow injuries to the radius can be reduced by using a stroke with less elbow flexion, and it is advisable to wear a reinforced arm cuff on the dorsal 1/4 of the hand, a radial/dorsal hand wrist, and an elbow guard to prevent radial ulnar injuries.

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