Engineering of single atomic Fe-N sites on hollow carbon cages to achieve highly reversible MoS anodes for Li-ion batteries.

Although the single atom electrocatalysts have been demonstrated as efficient catalysts for promoting LiS/NaS formation and decomposition in Li-S/Na-S batteries, the functional morphological and structural engineering capable of exposing more active sites is regarded as an essential factor to further enhance the catalytic activity. Here, we have synthesized a single atomically dispersed Fe sites embedded within hollow nitrogen doped carbon cages (Fe-N-HCN) using FeO spheres as an oxidant and sacrificial template, which is used as a high-efficiency catalyst for boosting the reversible capacity of MoS anode in lithium-ion batteries (LIBs). As expected, the electrochemical reaction of MoS/Fe-N-HCN anode exhibits higher reversibility than pure MoS electrodes.

Slurry-Phase Hydrogenation of Different Asphaltenes to Liquid Fuels on Dispersed MoS Nanocatalysts.

Asphaltene, the most complex and recalcitrant fraction of heavy oil, was investigated in this study to gain new insights into its structure and reactivity. Two types of asphaltenes, ECT-As and COB-As, were extracted from ethylene cracking tar (ECT) and Canada's oil sands bitumen (COB), respectively, and used as reactants for slurry-phase hydrogenation. Characterization of ECT-As and COB-As was carried out by a combination of techniques, including XRD, elemental analysis, simulated distillation, SEM, TEM, NMR, and FT-IR, to gain insights into their composition and structure.

A novel method of temperature compensation for piezoresistive microcantilever-based sensors.

Microcantilever with integrated piezoresistor has been applied to in situ surface stress measurement in the field of biochemical sensors. It is well known that piezoresistive cantilever-based sensors are sensitive to ambient temperature changing due to highly temperature-dependent piezoresistive effect and mismatch in thermal expansion of composite materials. This paper proposes a novel method of temperature drift compensation for microcantilever-based sensors with a piezoresistive full Wheatstone bridge integrated at the clamped ends by subtracting the amplified output voltage of the reference cantilever from the output voltage of the sensing cantilever through a simple temperature compensating circuit.

Optimization of sensing and feedback control for vibration/flutter of rotating disk by PZT actuators via air coupled pressure.

In this paper, a feedback control mechanism and its optimization for rotating disk vibration/flutter via changes of air-coupled pressure generated using piezoelectric patch actuators are studied. A thin disk rotates in an enclosure, which is equipped with a feedback control loop consisting of a micro-sensor, a signal processor, a power amplifier, and several piezoelectric (PZT) actuator patches distributed on the cover of the enclosure. The actuator patches are mounted on the inner or the outer surfaces of the enclosure to produce necessary control force required through the airflow around the disk.