4H-SiC has been widely exploited in semiconductor industry. Nevertheless, the scratch-free surface with less oxide layer (required for its high-performance) is difficult to realize at high efficiency. Hence, to address this issue, an electrochemical mechanical polishing (ECMP) test was conducted based on the electrochemical-mechanical balance between the SiC corrosion rate and the SiO2 layer removal rate. Firstly, we synthesized polystyrene (PS)/CeO2 core/shell abrasives, which have the potential to obtain the high-quality surface due to its elastic effect. These as-synthesized abrasives were then characterized by FESEM and XRD. Results showed the CeO2 shells were coated on the PS cores successfully. Next, equations of the SiO2 layer removal rate and the SiC corrosion rate were experimentally obtained based on the modified Preston's equation and the Faraday's law of electrolysis, respectively. Finally, a verified test for 4H-SiC-ECMP was conducted in a 0.2 M NaOH electrolyte solution containing 5.0 wt% PS/CeO2 abrasives. After ECMP, these samples were characterized by microscope, AFM, Raman spectrometer and profile-meter, respectively; and the scratch-reduction mechanisms were deduced based on these characterization results. Results showed under balanced conditions, the scratch-free surface (Ra: 0.449 nm) with less oxide layer was obtained at high efficiency (∼2.3 μm/h).

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In the last decade, immune checkpoint blockade (ICB) has revolutionized the standard of treatment for solid tumors. Despite success in several immunogenic tumor types evidenced by improved survival, ICB remains largely unresponsive, especially in “cold tumors” with poor lymphocyte infiltration. In addition, side effects such as immune-related adverse events (irAEs) are also obstacles for the clinical translation of ICB. Recent studies have shown that focused ultrasound (FUS), a non-invasive technology proven to be effective and safe for tumor treatment in clinical settings, could boost the therapeutic effect of ICB while alleviating the potential side effects. Most importantly, the application of FUS to ultrasound-sensitive small particles, such as microbubbles (MBs) or nanoparticles (NPs), allows for precise delivery and release of genetic materials, catalysts and chemotherapeutic agents to tumor sites, thus enhancing the anti-tumor effects of ICB while minimizing toxicity. In this review, we provide an updated overview of the progress made in recent years concerning ICB therapy assisted by FUS-controlled small-molecule delivery systems. We highlight the value of different FUS-augmented small-molecules delivery systems to ICB and describe the synergetic effects and underlying mechanisms of these combination strategies. Furthermore, we discuss the limitations of the current strategies and the possible ways that FUS-mediated small-molecule delivery systems could boost novel personalized ICB treatments for solid tumors.

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Fine-grained 7034 aluminium alloys were soldered with Zn–5Al filler metals, using liquid Ga as protective coatings to remove oxide films of the base and filler metals and prevent secondary oxidation. Holding times and coating modes were adjusted by experiments. Applying the Ga coating on both the base and filler metals caused the Ga enrichment in the α-Al particles and the formation of Mg2Ga5 intermetallic compound at the bonding interface, deteriorating joint mechanical performance. Ga enrichment was prevented by applying the coating on the filler metal alone, which avoided the early contact of Ga with Al substrate and reduced the mass of Ga in the joint. The tensile strength increased significantly to 159∼185 MPa with a sufficient holding time.