Surface activity of a series of fluoroether betaine amphoteric surfactants: Oxygen roles

As PFOS, PFOA and their derivatives were banned according to the Stockholm Convention for their potential bioaccumulation and toxicity, people attempted to substitute the legacy fluorosurfactants with short-chain ones. Although short-chain alternatives can alleviate bioaccumulation, surface activity was compromised. Fluorine industry kept seeking for effective solution. In this work, we prepared and investigated a series of fluoroether betaine surfactants for their surface activity and spreading property. The role of oxygen on surface activity was discussed. We found that insertion of oxygen atoms into fluorinated chain could increase hydrophobicity and thus enhance surface activity. The contribution of one oxygen is approximately half of that of a difluoromethylene group by experience. Moreover, introducing oxygen diversified the structure to fill in the gap of surface activity between short and long fluorosurfactants. In summary, this work provided basic knowledge for molecular design.

Design of a 3D Wilkinson power divider using through glass via technology

Due to its low electrical loss and low process cost, a glass interposer has been developed to provide a compelling alternative to the silicon-based interposer for packaging of future 2-D and 3-D ICs. In this study,through glass vias(TGVs) are used to implement 3-D inductors for minimal footprint and large quality factor. Using the inductors and parallel plate capacitors, a compact 3-D Wilkinson power divider is designed and analyzed.Compared with some reported power dividers, the proposed TGV-based circuit has an ultra-compact size and excellent electrical performance.

CNFET-based voltage rectifier circuit for biomedical implantable applications

Carbon nanotube field effect transistor（CNFET） shows lower threshold voltage and smaller leakage current in comparison to its CMOS counterpart. In this paper, two kinds of CNFET-based rectifiers, full-wave rectifiers and voltage doubler rectifiers are presented for biomedical implantable applications. Based on the standard 32 nm CNFET model, the electrical performance of CNFET rectifiers is analyzed and compared. Simulation results show the voltage conversion efficiency（VCE） and power conversion efficiency（PCE） achieve 70.82% and 72.49% for CNFET full-wave rectifiers and 56.60% and 61.17% for CNFET voltage double rectifiers at typical 1.0 V input voltage excitation, which are higher than that of CMOS design. Moreover, considering the controllable property of CNFET threshold voltage, the effect of various design parameters on the electrical performance is investigated.It is observed that the VCE and PCE of CNFET rectifier increase with increasing CNT diameter and number of tubes. The proposed results would provide some guidelines for design and optimization of CNFET-based rectifier circuits.