Absorbers with lightweight, low filler loading and broad absorption band are highly desirable for electromagnetic wave absorption field. Here, hollow Co1–xS microspheres constructed by nanosheets are fabricated via a facile synthetic method based on hydrothermal route. As an efficient wave absorber, the Co1–xS hollow spheres demonstrate excellent microwave absorption performance. With a weight content of only 3 wt%, the maximum reflection loss (RL) can reach as strong as −46.1 dB at 13.92 GHz and its qualified frequency bandwidth (with RL value over −10 dB) remarkably achieves 5.6 GHz, covering 35% of the entire measured bandwidth. In addition, compared with other cobalt sulfides (such as CoS2 and Co9S8), the Co1–xS microspheres with hollow structure exhibit more superior absorption intensity and broader qualified bandwidth. Therefore, this work provides a promising approach for the design and synthesis of hollow Co1–xS microspheres with lightweight and high‐performance microwave absorption.

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Good antiinfection properties of medical polymers, especially those used in artificial organs, are crucial to the minimization of microbial attack in nosocomial treatments. However, medical polymers fabricated by conventional methods usually have unstable and short-lived antimicrobial effects because of unsteady out-diffusion of the antibacterial species from the organic matrix. Here, we introduce a dual plasma implantation process to enhance the properties. An inorganic antibacterial element, copper, is introduced into a medical polymer, polyethylene (PE), by means of copper plasma immersion ion implantation (PIII) and a subsequent nitrogen PIII process is used to regulate the release of the implanted Cu. X-ray photoelectron spectroscopy and transmission electron microscopy reveal that a relatively large amount of copper of about 11% is implanted into PE to a depth of several hundred nanometers. Chemical analyses confirm that the implanted Cu does not bond with the polymer matrix. However, the N(2) plasma treatment produces various functional bonds such as C=N, and C[triple bond]N which exert appreciable influence on regulating the out-diffusion rate of copper. The large amount of embedded Cu, coupled with controlled release of the element to the surface, gives rise to excellent and long-lasting surface antibacterial properties of the plasma-treated polymer. The capability of controlling the release and storing the antibacterial reagent in a buried layer leads to better antimicrobial polymeric materials for medicine.

A physical model on dipole formation at high-k/SiO2 interface is proposed to study possible mechanism of flatband voltage (VFB) shift in metal-oxide-semiconductor device with high-k/metal gate structure. Dielectric contact induced gap states (DCIGS) on high-k or SiO2 side induced by high-k and SiO2 contact are assigned to dominant origin of dipole formation. DCIGS induced interface dipole is considered to cause VFB shift through charge transfer effect. Based on the proposed model, directions of dipoles at several high-k/SiO2 interfaces are predicted, and magnitudes of dipoles are approximately calculated. Both directions and magnitudes are in agreement with the reported results.