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The catalytic transformation of the biomass platform compound levulinic acid (LA) to γ-valerolactone (GVL) is a vital reaction to produce related renewable chemicals and fuels. Developing stable catalysts with highly dispersed and accessible ultrafine metal nanoparticle (NP) active sites for the hydrogenation of LA under solvent-free conditions is still a major challenge. Herein, a versatile nano-emulsion self-assembly method was employed to fabricate N-doped carbon nanospheres with a high specific surface area and hierarchically porous structure. Ultrafine Ru NPs were successfully anchored on the hierarchal porous N-doped carbon nanospheres (HPNC) with high dispersion. The obtained Ru/HPNC catalyst exhibited excellent catalytic performance for LA hydrogenation to GVL under solvent-free conditions with outstanding reusability. In contrast, Ru NPs embedded in other supports (including activated carbon and carbon nanotubes) were observed to be less effective under the same reaction conditions. The superior catalytic performance of the Ru/HPNC catalyst is due to the hierarchically porous catalyst structure, and accessible ultrafine Ru active sites which can promote the activation of CO bonds and H

The fabrication of catalysts with atomically dispersed metal active sites is a hot research topic in catalysis, but the controllable preparation of single-atom catalysts still possesses several challenges due to the aggregation tendency of active sites. Herein, an elaborate multistep protection strategy for preparation of atomically dispersed Fe atoms on three-dimensional N-doped hollow carbon spheres was reported. Experimental results show that the pre-separation of 1,10-phenanthroline, the anchoring effect with N sites, and the three-dimensional hollow spherical structure of the support are crucial to achieve atomic dispersion of Fe atoms. The obtained single-atom catalysts, defined as Fe-N@HCS-T (T represents the calcination temperatures), were detailed analyzed. Fe-N@HCS-T exhibited excellent catalytic activity and selectivity for the oxidation of ethylbenzene under mild reaction conditions. Furthermore, the prepared catalysts exhibit excellent stability and recyclability. Therefore, this study is expected to provide a feasible strategy for the design of high-efficiency single-atom catalysts for future catalytic applications.

Heterogeneous noble metal-based catalysts with stable, precise structures and high catalytic performance are of great research interest for sustainable catalysis. Herein, we designed the novel sandwich-like metal-organic-framework composite nanocatalyst UiO-66-NH2@Pt@mSiO2 using UiO-66-NH2@Pt as the core, and mesoporous SiO2 as the shell. The obtained UiO-66-NH2@Pt@mSiO2 catalyst shows a well-defined structure and interface, and the protection of the mSiO2 shell can efficiently prevent Pt NPs from aggregating and leaching in the reaction process. In the one-pot cascade reaction of nitroarenes and aromatic aldehydes to secondary amines, UiO-66-NH2@Pt@mSiO2 shows excellent catalytic performance due to acid catalytic sites provided by UiO-66-NH2 and Pt hydrogenation catalytic sites. Furthermore, the porous structure of the UiO-66-NH2@Pt@mSiO2 catalyst also enhances reactant diffusion and improves the reaction efficiency. This work provides a new avenue to meticulously design well-defined nanocatalysts with superior catalytic performance and stability for challenging reactions.

In order to obtain a better driving mechanism of the differential pump, a high-performance differential velocity vane pump was presented. The pump was driven by the novel eccentric non-circular gears. The working principle and structure of the differential pump were studied. The transmission mechanism of the high-order multisegment deformed eccentric non-circular gears were established, then the transmission characteristics were discussed. Finally an example was given. The example showed that the high-order multisegment deformed, eccentric non-circular gears could meet the large displacement requirements of the differential velocity vane pump.

Chemoselective hydrogenation of unsaturated organic compounds is a significant research topic in the catalysis field. Herein, a sulfur-doped ordered mesoporous carbon (SMC) material was prepared to anchor ultrafine platinum (Pt) clusters for the chemoselective hydrogenation of halogenated nitroarenes. The confinement effect of the ordered pores and the strong metal-support interaction caused by Pt clusters and sulfur atoms, efficiently suppress the aggregation and regulate the electronic states of the ultrafine Pt clusters. Thus, the hydrogenation of parachloronitrobenzene (p-CNB) shows high selectivity catalyzed by the ultrafine Pt clusters with electron-rich states. Meanwhile, the catalytic performance of the hydrogenation reaction catalyzed by Pt/SMC is capable of being maintained after at least 5 cycles, and the catalytic universality can also be applied to different halogenated nitroarenes hydrogenation. Therefore, this study may promote the research into the construction of noble metal-based catalysts for chemoselective hydrogenation reactions in green and sustainable chemical processes.

Heterogeneous noble metal-based catalysts with stable, precise structures and high catalytic performance are of great research interest for sustainable catalysis. Herein, we designed the novel sandwich-like metal-organic-framework composite nanocatalyst UiO-66-NH

Guidelines for the management of irritable bowel syndrome (IBS) recommend that psychological therapies should be considered, but their relative efficacy is unknown. We performed a protocol for systematic review and meta-analysis to try to resolve this uncertainty.Two individual researchers conducted the platform searches on Ovid Medline In-ProcessOther Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, Ovid PsycINFO, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus from inception to February 2022. Systematic review and meta-analysis of the data will be performed in STATA13.0 software according to the preferred reporting items for systematic reviews and meta-analyses protocols guidelines. Two authors independently performed the literature searching, data extraction, and quality evaluation. Risk of bias was assessed using the Cochrane Risk of Bias Tool for randomized controlled trials.A synthesis of current evidence of psychological interventions for IBS will be provided in this study.This result will provide a comprehensive analysis and synthesis to inform practitioners and policy makers about the effectiveness of psychological interventions for patients with IBS.

The transmission systems of the differential velocity vane pumps (DVVP) have periodic vibrations under loads. And it is not easy to find the reason. In order to optimize the performance of the pump, the authors proposed DVVP driven by the hybrid Higher-order Fourier non-circular gears and tested it. There were also similar periodic vibrations and noises under loads. Taking into account this phenomenon, the paper proposes fluid mechanics and solid mechanics simulation methodology to analyze the coupling dynamics between fluid and transmission system and reveals the reason. The results show that the pump has the reverse drive phenomenon, which is that the blades drive the non-circular gears when the suction and discharge is alternating. The reverse drive phenomenon leads the sign of the shaft torque to be changed in positive and negative way. So the transmission system produces torsional vibrations. In order to confirm the simulation results, micro strains of the input shaft of the pump impeller are measured by the Wheatstone bridge and wireless sensor technology. The relationships between strain and torque are obtained by experimental calibration, and then the true torque of input shaft is calculated indirectly. The experimental results are consistent to the simulation results. It is proven that the periodic vibrations are mainly caused by fluid solid coupling, which leads to periodic torsional vibration of the transmission system.

Transfer hydrogenation reactions using non-noble metal-based nanocatalysts are extensively attractive due to their low-cost and green reaction conditions. But construction of such catalysts with maximum metal atom efficiency and high catalytic activity is still a challenging research goal. Here, atomically dispersed Co catalysts with Co-N4 active sites were fabricated, which builds a bridge for transfer hydrogenation between nitroarenes and saturated N-heterocycles in aqueous solution. The TOF value of the transfer hydrogenation reaction is much higher than nanoparticle catalyst for this reaction. Density functional theory (DFT) calculations and control experiments reveal that the excellent performance origins from the Co-N4 sites, which combines the dehydrogenation of 1,2,3,4-tetrahydroquinoline with hydrogenation of nitrobenzene in one-pot. This work not only has an in-depth understanding of active sites but also shows a unique activity to the challenging, highly efficient, and green transfer hydrogenation reaction.

In recent years, with the development of GPU, based on the general purpose computation on graphics processors has became a new field. Aiming at the processing of GPU, this paper provides the formal description for data parallel mode, a detailed description of the CUDA programming mode land the principle of optimization. It shows by the comparative experiment that CUDA owns strongly of the ability to the parallel processing and provides new methods and ideas to GPGPU.