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The efficient use of renewable high-energy radiation (X/γ-rays or accelerated e‒) as the energy input for the chemical transformation of carbon dioxide (CO2) and water to energy-rich fuels holds new promise for a carbon-neutral, sustainable energy economy; however, such processes are challenging to implement, and require the assistance of catalysts capable of sensitizing the secondary electron scattering and providing active metal sites to bind intermediates. Herein, we report that atomic Cu-Ni dual-metal-sites embedded in a metal-organic framework matrix enable efficient and selective (~ 98%) conversion of CO2 to CH3OH in irradiated aqueous solutions. The reaction is initiated by the direct generation of CO2•‒ radicals via aqueous electrons attachment, followed by a series of interfacial reactions. We showed that the UiO-66(Hf) matrix serves as a radiation sensitizer to break electron yield limitation in water radiolysis, dramatically promoting CO2 activation and conversion efficiency. With the synergistic metal centers and a hydroxyl radical scavenger, we achieved stable and selective CH3OH production over multiple irradiation cycles. Pulse radiolysis experiments with theoretical calculations revealed the transient kinetics occurred on the nanosecond timescale and cascade hydrogenation steps. Our study highlighted an unprecedented catalytic route to produce CH3OH with CO2 feedstock and introduced a desirable atomic structure to improve performance.

It is difficult to realize a traveling wavemode current on a single conductor loop to generate a wideband circularly polarized (CP) radiation wave using a single feeding structure. In this communication, with the help of the characteristic mode analysis, we cut a wide gap in the annular ring conductor patch and design the feeding structure with capacitive coupling effect on the patch. By this way, the annular patch is effectively distributed with traveling wave currents and a printed annular ring antenna operating in the 2.4 GHz band is constructed. The experimental results show that the proposed antenna can generate CP radiation with impedance and axial ratio bandwidths of 26% and 10.6%, respectively. Meanwhile, this antenna has a good structural tolerance capability.

A discussion is conducted on the problems of ideological and political education, rotation learning in departments, clinical and scientific research capabilities, paper writing, and improvement of the quality of papers encountered by professional master of clinical medicine in the “two-track integration” mode during the standardized training of resident doctors. On that basis, several methods are proposed in the present study (e.g., stressing ideological education for professional masters, coordinating learn of professional skills, enhancing paper writing ability and scientific research ability, organizing a professional team of tutors). On that basis, this study summarizes the problems and challenges exposed in training professional medical students, especially under “two-track integration” mode, seeks to propose a novel idea to serve better for the “two-track integration” educational mode, including provide solutions to help students establish learning goals, to enhance their writing ability, to narrow the bridge between teachers and students, etc. All of which, aims to optimize the training of professional masters of clinical medicine, and give some feasible suggestions for subsequent research. Hopefully, the suggestions and proposal in this study would draw attention and serve better to increase the education quality on professional medical students.

High-performance ternary transition-metal chalcogenides (TMDs) are desired in various application fields. However, developing ternary TMDs with unique performance via an efficient and economical me...

MoS2 microrods constructed by ultrathin nanosheets have been synthesized, for the first time, by thermal decomposition of intermediate (NH4)2MoS4 crystals, which could not only provide the single-source for both the molybdenum and sulfur atoms, but also served as the self-sacrificed template. The well-defined microstructure was characterized by XRD, SEM, TEM, XPS, BET, respectively. The results indicated that MoS2 microrods with uniform morphology were assembled by defective ultrathin nanosheets. Moreover, these MoS2 microrods exhibit superior catalytic activity with the apparent rate constant (κapp) of 0.161 min−1 for the reduction of 4-nitrophenol (4-NP) by NaBH4. Encouragingly, the MoS2 microrods still show evident activity for the reduction of 4-NP after five cycle tests, which has significant importance for the application in the reduction of 4-NP to p-aminophenol (4-AP). Also, this method can be extended to construct other kinds of metal dichalcogenides (TMDs).

The present study proposes a new approach for direct CO 2 conversion using primary radicals from water irradiation. In order to ensure reduction of CO 2 into CO 2 •- by all the hydrated electrons, we use formate ions to scavenge simultaneously the parent oxidizing radicals H • and OH • producing the same transient CO 2 •- radicals. Conditions are optimized to obtain the highest conversion yield of CO 2 . The goal is achieved under mild conditions of room temperature, neutral pH and 1 atm of CO 2 pressure. All the available radicals are exploited for selectively converting CO 2 into oxalate that is accompanied by H 2 evolution. Besides, at high CO 2 pressure, CO is also produced via presolvated electron scavenging and the H • radicals with CO 2 •- . The mechanism presented accounts for the results and also sheds light on the data in the literature. The radiolytic approach is a mild and scalable route of direct CO 2 capture at the source in industry and the products, oxalate salt and H 2 , can be easily separated.

The present study proposes a new approach for direct CO

A series of experiments was performed to investigate the enhancement effect of micro fin, contact pressure, and interface temperature on thermal contact conductance. The specimens were made of 7075 aluminum alloy. The contact surfaces of specimens with micro fin were specially machined such that two specimens were coaxially inlayed together. Contact pressure ranged from 2 MPa to 4.2 MPa, and interface temperature ranged from 165 °C to 180 °C and 215 °C to 227 °C. Experimental results showed that the micro fin could enhance thermal contact conductance, and the contact heat transfer enhancement effects caused by the micro fin gradually increased with contact pressure. Thermal contact conductance was high under higher interface temperature. The loading process changed the enhancing effect of the micro fin, and enhancement of contact heat transfer was greater in the unloading process than in the loading process. A qualitative analysis on the enhancement effect was conducted to explain the contact heat transfer enhancement effect for different micro-finned surfaces.

Willow branch-shaped MoS2/CdS heterojunctions are successfully synthesized for the first time by a facile one-pot hydrothermal method. The as-prepared samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption measurements, diffuse reflectance spectroscopy, and photoelectrochemical and photoluminescence spectroscopy tests. The photocatalytic hydrogen evolution activities of the samples were evaluated under visible light irradiation. The resulting MoS2/CdS heterojunctions exhibit a much improved photocatalytic hydrogen evolution activity than that obtained with CdS and MoS2. In particular, the optimized MC-5 (5 at.% MoS2/CdS) photocatalyst achieved the highest hydrogen production rate of 250.8 μmol h-1, which is 28 times higher than that of pristine CdS. The apparent quantum efficiency (AQE) at 420 nm was 3.66%. Further detailed characterizations revealed that the enhanced photocatalytic activity of the MoS2/CdS heterojunctions could be attributed to the efficient transfer and separation of photogenerated charge carriers resulting from the core-shell structure and the close contact between MoS2 nanosheets and CdS single-crystal nanorods, as well as to increased visible light absorption. A tentative mechanism for photocatalytic H2 evolution by MoS2/CdS heterojunctions was proposed. This work will open up new opportunities for developing more efficient photocatalysts for water splitting.

In this paper, patch antenna structures are studied to simultaneously excite the ground radiation mode and patch radiation mode. Based on the analysis of characteristic current distribution on the ground plane of patch antenna, an exciting method of the ground radiation mode is proposed. Then a dual-mode patch antenna of patch radiation and ground radiation is designed, which can achieve a wideband radiation using two modes resonating at two adjacent frequencies. To improve the radiation efficiency of the ground mode, the electric field distribution of the dual-mode antenna is investigated in detail and the electric field models for two modes are constructed. It is suggested that the additional notches introduced on the ground plane can enhance the resonance component of the ground mode. By this way, the modified patch antenna presents better radiation efficiency over the operating band. The measurement results show that the relative bandwidth of the patch antenna prototype with the notches is about 16.2%, defined by the reflection coefficient less than -10 dB. The proposed dual-mode antennas have the inherent characteristics of weak directivity, for that the antenna application scenarios also are indicated.

With the rapid development such as vehicle collision avoidance radars and the fifth generation mobile communication systems, millimeter wave technologies have become the current research hotspot. To improve the corresponding system performances and popularize their applications, the key components such as antennas need to be designed using new concepts and technologies. The on-chip antenna, which is part of the chip system rather than a stand-alone device, is a typical example of this design philosophy. Considering the high loss and high dielectric constant of the silicon-based substrate, however, the implementation of the on-chip antenna is difficult. In this paper, using the substrate integrated waveguide technology and loading the split ring resonators (SRR) of the metamaterial structure, an on-chip antenna based on the silicon substrate is constructed. This antenna structure achieves high radiation efficiency at 77GHz and has good directivity. Thus, this proposed on-chip antenna can be used as the array element of vehicle-mounted millimeter-wave radar to realize the high integration of the antenna structure and high directionality of the radiation beam.

MoS₂ microrods constructed by ultrathin nanosheets have been synthesized, for the first time, by thermal decomposition of intermediate (NH₄)₂MoS₄ crystals, which could not only provide the single-source for both the molybdenum and sulfur atoms, but also served as the self-sacrificed template. The well-defined microstructure was characterized by XRD, SEM, TEM, XPS, BET, respectively. The results indicated that MoS₂ microrods with uniform morphology were assembled by defective ultrathin nanosheets. Moreover, these MoS₂ microrods exhibit superior catalytic activity with the apparent rate constant (

p-Nitrophenol (p-NP), a well-known organic pollutant in industrial and agricultural wastewater, is difficult to degrade. Therefore, an exploiting efficient and economical reductant is of great significance for environmental remediation and human health. Herein, MoS2 nanocrystals with different morphologies were successfully prepared by a simple hydrothermal method in the mixed solution of ethylenediamine and ethylene glycol. The morphology can be readily controlled by tuning the volume ratio of ethylenediamine to the solvent (R). Moreover, well-crystallized MoS2 nanocrystals were developed by the following heat treatment process. The as-prepared MoS2 nanocrystals were employed as catalysts for the reduction of toxic p-NP to industrially beneficial p-aminophenol (p-AP). It was clearly revealed that both the morphology and crystallinity play critical roles in the catalytic reduction efficiency. Among the MoS2 samples, the optimized R75 sample with a rough surface exhibits the highest rate constant of kapp = 0.3906 min−1 for the reduction of p-NP, while improved crystallinity will decrease the catalytic efficiency. These novel findings can promote the development of a new non-noble metal catalyst which can be used for wastewater reductive treatment.

Design and construction of highly efficient and stable co-catalysts are critical for the photocatalytic H2 generation from water. In this work, we report the novel CdS/CoMoSx core-shell nanowires (CCMS NWs) prepared by a facile in situ synthesis method. The in situ growth of amorphous CoMoSx shell on the surface of CdS NWs core efficiently promoted the photocatalytic H2 evolution under visible light irradiation. The optimized CCMS sample containing 15 mol% CoMoSx (CCMS-15) achieves a H2 evolution rate as high as 477.96 μmol·h−1 under visible light irradiation, up to 26.3 times over bare CdS (18.2 μmol·h−1). Moreover, the constructed core-shell CdS/CoMoSx photocatalyst shows a long-term stability without noticeable activity degradation. Based on the detailed analyses of PL, UV–vis DRS, transient photocurrent responses, EIS, Mott-Schottky plots and ESR, the significantly enhanced activity is ascribed to the synergistic effect of increased visible light absorption, suppressed photo-generated charge carries recombination and the amorphous defective structure of CoMoSx co-catalyst. In consideration of its facile synthesis, low cost, and superior performance, the amorphous CoMoSx appears to be promising co-catalyst for photocatalytic water splitting.