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A single-Rh-site catalyst (Rh-TPISP) that was ionically-embedded on a P(V) quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation. The [Rh(CO)I3]2– unit was proposed to be the active center of Rh-TPISP for the carbonylation reaction based on detailed Rh L3-edge X-ray absorption near edge structure (XANES), X-ray photoelectron spectroscopy (XPS), and Rh extended X-ray absorption fine structure (EXAFS) analyses. As the highlight of this study, Rh-TPISP displayed distinctly higher activity for heterogeneous ethanol carbonylation than the reported catalytic systems in which [Rh(CO)2I2]− is the traditional active center. A TOF of 350 h−1 was obtained for the reaction over [Rh(CO)I3]2–, with >95% propionyl selectivity at 3.5 MPa and 468 K. No deactivation was detected during a near 1000 h running test. The more electron-rich Rh center was thought to be crucial for explaining the superior activity and selectivity of Rh-TPISP, and the formation of two ionic bonds between [Rh(CO)I3]2– and the cationic P(V) framework ([P]+) of the polymer was suggested to play a key role in firmly immobilizing the active species to prevent Rh leaching.

A novel Rh based porous composed N polymer with hierarchical pore, high surface area and high thermal stability (Rh-POL-2BPY) was successfully obtained by impregnation of Rh2(CO)4Cl2 solution of dichloromethane. And based on Rh species as the most active carbonylation site, Rh-POL-2BPY was selected as a catalyst applied in heterogeneous methanol carbonylation system and behaved excellent carbonylation activity (TOF ≈ 1400 h−1) under 195 °C, 2.5 MPa, higher than the corresponding homogeneous system without acetic acid. In addition, contrast to the most reported unstable heterogeneous methanol carbonylation systems, Rh-POL-2BPY could maintain incredibly outstanding stability for near 400 h owing to the firm coordination bond between Rh and N and high exposed N content in the polymer. Here, POL-2BPY apart from its heat-resisting property acts as massive rivets to immobilize the Rh species in its framework solidly during carbonylation process. XPS, XANES, HAADF-STEM and EXAFS results verify the N species of bipyridine, the single atom dispersion of Rh and Rh N coordination bond. And above all, the novel five-coordinated Rh center is proposed as the real active site of methanol carbonylation by EXAFS spectra.

One-dimensional (1D) TiO2 nanoarrays (NAs) were synthesized by a hydrothermal process, and Ag nanoparticles (NPs) were deposited on the arrays using a photodeposition technique. The content of Ag NPs was changed by altering the photodeposition time to 0, 5, 10, 15, and 20 min. The influence of the content of Ag NPs on the structural, morphological, compositional, optical, and photocatalytic properties of 1D TiO2 NAs was systematically investigated. The results demonstrated that 1D TiO2 NAs showed improved visible light absorption and enhanced photocatalytic properties after deposition of Ag NPs. Compared with bare TiO2 NAs, the TiO2 NAs after deposition of Ag NPs for 15 min showed the best optical and photoelectrochemical properties, and photodegradation efficiency (98.8 %).

Single-crystalline TiO2 nanorod arrays (TiO2 NRAs) with dominant {001} facets sensitized with CdS nanosheets were prepared on fluorine-doped tin oxide (FTO) substrate by a simple combination of hydrothermal and successive ion layer absorption and reaction (SILAR) methods. The amount of CdS nanosheets was controlled by changing reaction time (0, 2, 6, and 10 min) in SILAR process. The effects of SILAR time on the microstructure, morphology, and optical and photoelectrochemical properties of TiO2 NRAs were investigated. Changing of SILRA times are accompanied by significant variations of optical properties including a decrease of the band gap from 2.98 to 2.41 eV and a red absorption peak shift from ultraviolet to visible region. Notably, the photoelectrochemical performance of TiO2 NRAs after 6 min SILAR deposition of CdS nonosheets improved significantly, displaying an optimal photocurrent density of 1.5 mA cm−2, which is about 15 times higher than that of pure TiO2 NRAs. This enhanced photoelectrochemical properties due to the synergistic effect of CdS nanosheets and rutile TiO2 NRAs with highly reactive {001} facets.

To achieve vibration energy collection in multiple directions, this paper reports a piezoelectric power generator with an axisymmetrically distributed PVDF array, which is used to acquire 2D vibration energy and monitor the vibration direction. The simulations and the experiments demonstrated that the flexible cylinder with an arc-shaped axisymmetrically distributed PVDF array, can harvest vibration energy form multiple directions. Meanwhile, the concept of angular bandwidth is proposed, which can describe the multi-directional vibration energy capability of the harvester. Experiments show that the design has a large AB value (89.2°). Furthermore, increase the output performance of the harvest by reverse series and parallel connection. Finally, a detailed study and summary of the output characteristics of all PVDFs in PVEH confirm that PVEH has potential as a vibration direction sensor. The PVEH can monitor the vibration direction of 8 areas in real-time.

An analytical surface potential model for the Dual Material Gate Stack (DUMGAS) fully depleted SOI MOSFET is developed based on the exact resultant solution of two dimensional Poisson equation. The model includes the effects of drain biases, gate workfunction, different combination length of Gate1 and Gate2, gate oxide thickness, source/drain doping concentration, substrate doping concentration and buried oxide thickness. More attention has been paid on seeking to explain the attributes of the DUMGAS fully depleted SOI MOSFET such as suppressing Drain-induced Barrier Lowering (DIBL), accelerating carrier drift velocity and device speed. The model is verified by comparison to the simulated results using the device simulator MEDICI. The accuracy of the results obtained using our analytical model is verified using 2-D numerical simulations. The model not only offers the physical insight into device physics but also provides the basic designing guideline for the device.

All digital delay-locked loops are widely used to solve the clock skew in modern day VLSI. However, the conventional SARDLL has the dead-lock problem, which limits its applications. So an improved SAR controller without dead-lock is proposed by embedding a restarting module into the conventional SAR controller. Using the improved SAR controller, a fast locking and relocking all digital SARDLL is implemented in 0.18μm CMOS . Post-layout transistor-level simulation results show that the lock-in and relock-in time are both within N cycles of input clock for N-bit SAR controller.