摘要：Clearly understanding the structure-function relationship and rational design of efficient CO2 electrocatalysts are still the *** article describes the molecular origin of high selectivity of formic acid on N-doped SnO2 nanoparticles,which obtained via thermal treatment of g-C3N4 and SnCl2·2H2O *** with density functional theory(DFT)calculations,we discover that N-doping effectively introduces oxygen vacancies and increases the charge density of Sn sites,which plays a positive role in CO2 *** addition,N-doping further regulates the adsorption energy of^*OCHO,^*COOH,^*H and promotes HCOOH *** from above modulation,the obtained N-doped SnO2 catalysts with oxygen vacancies(Ov-N-SnO2)exhibit faradaic efficiency of 93% for C1 formation,88% for HCOOH production and well-suppression of H2 evolution over a wide range of potentials.

摘要：Solar energy has promising potential for building sustainable *** of solar energy into solar fuels plays a crucial role in overcoming the intennittent nature of the renewable energy source.A pliotoclectrochernical (PEC) cell that employs semiconductor as photoelectrode to split water into hydrogen or fixing carbon dioxide (CO2) into hydrocarbon fuels provides great potential to achieve zcrocarbon-oiiiission society.A proper design of those semiconductor photoelectrodes thus directly influences the performance of the PEC *** this review,we investigate the strategics that have been put towards the design of efficiont photoelectrodes for PEC water splitting and CO2 reduction in recent years and provide sonic future design directions toward noxt-goneration FEC cells for water splitting and CO2 reduction.

摘要：Based on principles of electromagnetic fluid dynamics the exerted forces and movement states of melted aluminum in the traditional reduction cells and the drained cells were compared and analyzed in this paper. And based on the theory of slow movement, a formula in respect of the drained angle was derived, i.e. θ≥(J zB x-J xB z)ρg-(J xB y-J yB x ). It can be seen that the drained slope can be decided by respectively multiplying the area current densities and magnetic induction intensities in three coordinate directions in aluminum reduction cells, and the drained slope is approximate to 0.6% derived from typical data based on measurement and calculation, which implies that the key parameter is obtained in designing of drained cells. The results can be used for a designing basis for drained cathodes.

摘要：In this study we designed a novel,cost‐efficient and green method for the synthesis of copper nanoparticles(Cu NPs)supported on manganese dioxide(MnO2)NPs,using Centella asiatica *** extract as a naturally‐sourced reducing agent,without stabilizers or *** synthetic process is environmentally‐friendly and avoids the use of toxic reducing *** hydroxyl groups in the leaf extract are believed to reduce Cu2+in solution to generate Cu NPs that are subsequently stabilized on the MnO2NP *** resulting Cu/MnO2nanocomposite was fully characterized using X‐ray diffraction,transmission electron microscopy,field emission scanning electron microscopy,energy‐dispersive X‐ray spectroscopy and Fourier transform infrared *** material was found to function as a highly active,efficient and recyclable heterogeneous catalyst for the reduction of Congo red,rhodamine B and methylene blue as well as nitro compounds such as2,4‐dinitrophenylhydrazine and4‐nitrophenol in the presence of NaBH4in aqueous media at ambient *** high stability of the Cu/MnO2nanocomposite also allows the catalyst to be separated and reused several times without any significant loss of activity.?2018,Dalian Institute of Chemical Physics,Chinese Academy of *** by Elsevier *** rights reserved.

摘要：Three new control factors are presented for calculating the multipole mode number （MMN） efficiently and precisely. The effects of these control factors on the number of integral samples and the precision of multilevel fast multipole algorithm （MLFMA） are investigated. A new approach based on control factors which is proven to be able to improve the computational efficiency and reduce the needed memory significantly as well as ensuring the proper precision. For three aircraft models,the improved MLFMA is employed to analyze their multi-frequency scattering characteristics. It is found that aircraft shape can influence radar cross section （RCS） in different frequency zones. Both the multi-frequency RCS reduction characteristics of shape stealth aircraft and the conventional aircraft with stealth design taken into account are investigated,and the results show that shape stealth exhibits significant RCS reduction in the resonance and high-frequency zones,and with a weaker influence in the Rayleigh zone. Compared with radar absorbing material （RAM）,shape stealth yields a wider multi-frequency RCS reduction. The above-mentioned results can be applied to stealth design for multiple frequencies or even for all frequencies.

摘要：Electrochemical CO2 reduction to chemicals or fuels presents one of the most promising strategies for managing the global carbon balance, which yet poses a significant challenge due to lack of efficient and durable electrocatalyst as well as the understanding of the CO2 reduction reaction(CO2RR) *** from the large surface area, high electrical conductivity, and tunable structure, carbon-based metal-free materials(CMs) have been extensively studied as cost-effective electrocatalysts for *** development of CMs with low cost, high activity and durability for CO2RR has been considered as one of the most active and competitive directions in electrochemistry and material *** this review article,some up-to-date strategies in improving the CO2RR performance on CMs are ***, the approaches to optimize the adsorption of CO2RR intermediates, such as tuning the physical and electronic structure are introduced, which can enhance the electrocatalytic activity of CMs ***, some design strategies are proposed to prepare CMs with high activity and selectivity for CO2RR.

摘要：Diffractive diffusers (phase gratings) are routinely used for homogenizing and beam shaping for laser beam applications. Another use for diffractive diffusers is in the reduction of speckle for pico-projection systems. While diffusers are unable to completely eliminate speckle they can be utilized to decrease the resultant contrast to provide a more visually acceptable image. Research has been conducted to quantify and measure the diffusers overall ability in speckle reduction. A theoretical Fourier optics model is used to provide the diffuser’s stationary and in-motion performance in terms of the resultant contrast level. Contrast measurements of two diffractive diffusers are calculated theoretically and compared with experimental results. Having a working theoretical model to accurately predict the performance of the diffractive diffuser allows for the verification of new diffuser designs specifically for pico-projection system applications.

摘要：In recent years, graphical processing unit （GPU）-accelerated intelligent algorithms have been widely utilized for solving combination optimization problems, which are NP-hard, These intelligent algorithms involves a common operation, namely reduction, in which the best suitable candidate solution in the neighborhood is selected. As one of the main procedures, it is necessary to optimize the reduction on the GPU. In this paper, we propose an enhanced warp-based reduction on the GPU. Compared with existing block-based reduction methods, our method exploit efficiently the potential of implementation at warp level, which better matches the characteristics of current GPU architecture. Firstly, in order to improve the global memory access performance, the vectoring accessing is utilized. Secondly, at the level of thread block reduction, an enhanced warp-based reduction on the shared memory are presented to form partial results. Thirdly, for the configuration of the number of thread blocks, the number of thread blocks can be obtained by maximizing the size of thread block and the maximum size of threads per stream multi-processor on GPU. Finally, the proposed method is evaluated on three generations of NVIDIA GPUs with the better performances than previous methods.

摘要：Beam emittance reduction is an effective method to increase the brightness of a synchrotron light *** wiggler can play a role in the beam emittance reduction by increasing the horizontal damping partition number.A replacement of the quadrupoles in the arc section with short combined function dipoles will construct a single-periodic Robinson wiggler in the SSRF storage *** scheme provides a lower beam emittance,without occupying any straight *** analysis is presented in this paper.

摘要：Strong shock waves and flow separation often occur during the integration of nacelle and airframe for blended-wing-bodies with podded engines. To address this problem, this paper presents an integration method with numerical simulations. The philosophy of channeling flow and avoiding the throat effect on the nacelle and airframe is established based on the analysis of flow interference in the initial configuration. A parametric integration design method is proposed from twodimensional plane to three-dimensional space with control mechanisms and selection principles of the key parameters determined by their influences. Results show that strong shock waves and flow separation can be successfully eliminated under the influence of both the reshaped channel and decelerated inflow below the nacelle. Supersonic regions around the nacelle are effectively reduced, concentrating mainly on the lip position. Thus, a significant cruise drag reduction(8.7%) is achieved though the pressure drag of the nacelle increases.