This paper presents a new jetting dispenser which is applicable to high-frequency microelectronic packaging. In order to achieve high frequency glue jetting and improve the stability of jetting dispensers, we redesign a novel displacement amplifying mechanism, and a new on–off valve jetting dispenser driven by piezoelectric actuators is developed. Firstly, the core part of this jetting dispenser—the displacement amplifying mechanism with a corner-filleted flexure hinge—is proposed and a comparison with the previous structure is carried out; then the characteristic dimensional parameters of the amplifying mechanism are determined by theoretical calculation and finite element analysis. Secondly, a prototype of the dispenser with the displacement amplifying mechanism is fabricated based on the determined parameters. We use a laser displacement sensor to test the displacement of the needle, and a maximum amplifying displacement output of 367 µm is obtained under an applied 200 V to the piezoelectric actuator, which is consistent with the simulation result and meets the requirement of high displacement output. Thirdly, we build an integrated testing system. Mixed glycerol/ethanol is chosen as the experimental dispensing glue, and the experiment and analysis of a droplet diameter are conducted. A higher jetting frequency of 400 Hz and a smaller droplet diameter of 525 µm are achieved with the glycerol/ethanol mixture, and the characteristics of consistency and temperature influencing the droplet diameter are verified by experiments.

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The formation of chemical bonds between metal ions and their supports is an effective strategy to achieve good catalytic activity. However, both the synthesis of active metal species on a support and control of their coordination environment are still challenging. Here, we show the use of an organic compound to produce tubular carbon nitride (TCN) as a support for Pd nanoparticles (NPs), creating a composite material (NP-Pd-TCN). It was found that Pd ions preferentially bind with the electron-rich N atoms of TCN, leading to strong metal-support interactions that benefit charge transfer from g-C 3 N 4 to Pd. X-ray absorption spectroscopy further revealed that the metal-support interactions resulted in the formation of Pd-N bonds, which are responsible for the improvement in the charge dynamics as evidenced by the results from various techniques including photoluminescence (PL) spectroscopy, photocurrent measurements, and electrochemical impedance spectroscopy (EIS). Owing to the good dynamical properties, NP-Pd-TCN was used for photocatalytic hydrogen evolution under visible-light irradiation (λ > 420 nm) and an excellent evolution rate of ~ 381 μmol•h −1 (0.02 g of the photocatalyst) was attained. This work aims to promote a strategy to synthesize efficient photocatalysts for hydrogen production by controllably introducing metal nanoparticles on a support and in the meantime forming chemical bonds to achieve intimate metal-support contact.