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To address the clinical need for readily available small diameter vascular grafts, biomimetic tubular scaffolds were developed for rapid in situ blood vessel regeneration. The tubular scaffolds were designed to have an inner layer that is porous, interconnected, and with a nanofibrous architecture, which provided an excellent microenvironment for host cell invasion and proliferation. Through the synthesis of poly(spirolactic-co-lactic acid) (PSLA), a highly functional polymer with a norbornene substituting a methyl group in poly(l-lactic acid) (PLLA), we were able to covalently attach biomolecules onto the polymer backbone via thiol-ene click chemistry to impart desirable functionalities to the tubular scaffolds. Specifically, heparin was conjugated on the scaffolds in order to prevent thrombosis when implanted in situ. By controlling the amount of covalently attached heparin we were able to modulate the physical properties of the tubular scaffold, resulting in tunable wettability and degradation rate while retaining the porous and nanofibrous morphology. The scaffolds were successfully tested as rat abdominal aortic replacements. Patency and viability were confirmed through dynamic ultrasound and histological analysis of the regenerated tissue. The harvested tissue showed excellent vascular cellular infiltration, proliferation, and migration with laminar cellular arrangement. Furthermore, we achieved both complete reendothelialization of the vessel lumen and native-like media extracellular matrix. No signs of aneurysm or hyperplasia were observed after 3 months of vessel replacement. Taken together, we have developed an effective vascular graft able to generate small diameter blood vessels that can function in a rat model.

We introduce Infinite Hidden Markov (IHM) models to forecasting realized volatilities of crude oil futures markets with exogenous factors. With these IHM models, we lift the restriction of a pre-defined number of regimes and allow for an unknown number of different parameter regimes and breakpoints. We employ two types of infinite hidden Markov models to accommodate structural breaks incurred by policy changes, exogenous shocks, and other factors. We find that IHM-HAR models outperform all other non-switching variants. In regard to forecasting performance, IHM-HAR models with exogenous factors such as realized volatilities of competing futures markets and the S&P500 are superior model choices for short-term forecasts. For longer-term forecasts, the equity channel shows only little positive impact. Evidence of economic gains in portfolio construction based on IHM-HAR forecasts is provided.

The catalysts’ redox capacity and surface acidity was important during the catalytic combustion of chlorobenzene (CB). CeO2 showed great attractiveness due to its high oxygen storage capacity. Furthermore, the increase of acidity on the catalyst surface could improve the resistance to the chlorine poisoning. In this work, the silicotungstic (HSiW) modified CeO2 catalysts prepared by four cerium salts and exhibited the different morphologies and catalytic activity. The HSiW modified CeO2 catalyst prepared by Ce(CH3COO)3 (Cat-A) exhibited the best catalytic activity due to its abundant surface weak acid sites, more Ce3+ species and surface adsorption oxygen. The HSiW mainly located on the CeO2 (111) planes of the Cat-A, which was conducive to redox property of CeO2, thus promoting the deep oxidation of CB. Meanwhile the redox ability together with the weak acidity influenced the catalytic efficiency at low temperature. And the redox ability played a major role at high temperature. In addition, the Cat-A still possessed high stability and water resistance and maintained high activity after continuous catalytic oxidation of CB at 235 and 295 °C for 100h, exhibiting the possibility of industrial application.

This paper investigates the realised volatility connectedness of US crude oil futures and five China's agricultural commodity futures using connectedness measures and high-frequency data. Time-varying volatility connectedness characteristics are identified by combining a multivariate heteroscedastic autoregressive (HAR) model with the DCC-GARCH model. The results verify the existence of volatility spillover from the US crude oil market to China's agricultural commodity markets, although the magnitude of this spillover is weak. Furthermore, the realised volatility is decomposed into positive and negative components to identify the asymmetric effect of volatility connectedness. The results show that market interdependence has obviously increased for negative volatility relative to positive volatility, implying that volatility transmission has a leverage effect across markets.

The catalytic activity and durability of catalysts were severely affected by preparation method. A series of Co-La catalysts were prepared and used to catlytic oxidation of toluene via sol–gel (SG), coprecipitation (CP), one-pot (OP) and physical mixing (PM) methods. The order of catalytic activity was SG > CP > OP > PM. SG catalyst exhibited the lowest apparent activation energy (Ea = 51.9 kJ/mol), the largest reaction rate (Rs), suggesting that the catalytic oxidation of toluene was more easily occured. SG catalyst possessed the smallest grain size (9.8 nm) and the largest SBET (41.4 m2/g), indicating that more active sites were provided. Meanwhile, it possessed the weakest Co-O bond strength, the abundant Co3+, active oxygen species and the excellent low-temperature reducibility, which could enhance the oxygen mobility and the redox performance. SG catalyst exhibited the excellent stability and durability, showing a great potential for industrial application.

The catalytic oxidation of toluene was investigated over CeO2-MnOx catalysts with the different cerium sources. The CeO2-MnOx catalyst synthesized by ceric ammonium nitrate (marked as Cat-A) possessed the superior catalytic performance among the samples. Notably, the synergistic effect between CeO2 and MnOx could provide more amounts of oxygen vacancy, the highest concentration of Mn3+ and the highest Ce3+ contents, which resulted in the outstanding oxygen mobility, causing the improvement of catalytic activity. In brief, the catalytic performance of CeO2-MnOx was closely related to the different modulation cerium sources during the preparation process.

Video dubbing is a new type of language learning practice. Because of the fun it brings into learning, video dubbing mobile applications have become quite popular. During video dubbing, learners not only mimic characters’ pronunciations but also other voicing characteristics, e.g., emotions. In this study, we collected a corpus from Liulishuo English learning App’s video dubbing practices and investigated three research questions. We find that L2 learners do try to mimic emotions via their voices, and human raters tend to focus more on the emotion production aspect when evaluating dubbing performance. Furthermore, we develop state-of-the-art speech emotion recognition technology and show it can be used for evaluating emotion production automatically.

A series of Mn2O3 catalysts were prepared by different hydrothermal temperatures and employed to the catalytic oxidation of benzene due to their high activity. The Mn-120 sample with three-dimensional (3D) hierarchical cube-like morphology mainly exposed (2 1 1) crystal plane exhibited the best catalytic activity for the oxidation of benzene and achieved the benzene conversion of 90% at 248 °C. Meanwhile, the best catalytic performance of the Mn-120 sample was attributed to the most amounts of the Mn3+ species and surface-adsorbed oxygen. With the increase of Mn3+ species, the oxygen binding capacity of Mn-120 was reduced, which could increase its oxygen mobility. The abundant adsorbed oxygen species of Mn-120 could improve the replenishment capacity of lattice oxygen species, and the reaction pathway of catalytic oxidation of benzene over MnO2 obeyed the Mars-Van-Krevelen (MVK) mechanism.

Catalytic combustion is an effective and economic technology to remove volatile organic compounds (VOCs). The La2O3, Co3O4, 90Co-10La, 80Co-20La and 70Co-30La samples were prepared via traditional precipitation means, and employed for the catalytic oxidation of toluene. Coupled with XRD, SEM, BET, Ranman, XPS, O2-TPD and H2-TPR analyses, it were found that the addition of LaOx could change the microstructure and redox ability of catalyst, resulting in the formation of LaCoO3 perovskite and the increase in the concentrations of Co2+ and Oads. The 80Co-20La sample exhibited the best toluene conversion (T90 = 242 °C), CO2 selectivity, stability, the optimal specific reaction rates (Rs = 2.0 × 10−3 mmol h−1m−2) and Ea (17.4 kJ/mol). The high catalytic efficiency could be explained by the enhanced synergistic effect between LaOx and CoOx due to the appropriate incorporation of LaOx, and the formed more LaCoO3 perovskite. It was related to the concentrations of Co2+ and Oads, which was beneficial to the low-temperature reducibility, and thus catalytic performance at low temperature was improved. The present work provids a useful idea for the rational design of the removal of VOCs for using transition/rare earth bimetallic oxides efficient to replace the noble metal catalysts.

The 2.5-terahertz quantum cascade lasers (THz QCLs) based on first-order distributed feedback (DFB) Bragg grating are reported. The loss and threshold gain within different grating duty cycles are calculated according to the mode-coupling theory. The laser output power reaches up to record values of 34.1 mW in pulse mode and 23.4 mW in continuous wave mode at 15 K. The threshold current density is as low as 125 A / cm2. The single-mode emission is achieved, and the side-mode suppression ratio is 12 dB. In addition, the device is bonded together with the other two DFB THz QCLs (2.9 and 3.0 THz) on a copper chip. The simultaneous different wavelength emissions with single mode are successfully realized.

An electrothermal bimorph micromirror with integrated temperature control is presented. The central mirror plate position is controlled against the ambient temperature variation through a thermally-isolated frame with embedded Pt heaters and temperature sensors.

This paper reports recent works on calibrating peak power sensors with the measurement traceability to a primary power standard, microcalorimeter. Several practical measurement setups have been evaluated and compared. Those uncertainty components relevant and significant to the calibration process are also discussed.

This paper reports recent theoretical modeling and analysis of traceable peak envelope power measurements for mobile communications. Double Sideband Large Carrier (DSB-LC) amplitude modulation has been used, for establishing the measurement traceability to primary RF and microwave power standard. In this work, the reference peak envelope power calculated from modulation index and reference average power is used in calibrations. This is followed by performance comparison of the proposed model with detailed uncertainty analysis.