摘要：With the ever-pressing issues of global energy demand and environmental pollution,molecular hydrogen has been receiving increasing attention as a clean alternative energy *** hydrogen production,the design and development of high-performance catalysts remains rather *** the compositions and structures of catalyst interfaces have paramount influences on the catalytic performances,the central topic here has always been to design and engineer the interface structures via rational routes so as to boost the activities and stabilities of electrocatalysts on hydrogen evolution reaction(HER).Here in this review,we focus on the design and preparation of multi-scale catalysts specifically catering to HER *** start from the design and structure-activity relationship of catalytic nanostructures,summarize the research progresses related to HER nanocatalysts,and interpret their high activities from the atomistic perspective;then,we review the studies regarding the design,preparation,HER applications and structure-activity relationship of single-atom site catalysts(SASCs),and thereupon discuss the future directions in designing HER-oriented *** the end of this review,we present an outlook on the development trends and faced challenges of catalysts for electrochemical HER.

摘要：Well-dispersed bimetallic NiRh nanoparticles （NPs） with different compositions supported on nitrogen-doped porous carbon （NPC） derived from metal-organic frameworks （ZIF-8） were synthesized through a co-reduction method. The NPC-900 supported NiRh catalyst exhibits the highest catalytic activity and 100% hydrogen selectivity toward hydrogen generation from hydrazine. These properties might be attributed to the high surface area and high graphitization of the NPC. This strategy may open up a new avenue for designing high-performance catalysts by utilizing NPC as a support to anchor active metal NPs for additional applications.

摘要：Modern distance education essentially differs from traditional pattern of education in providing personalized education support service. This paper analyzes the status in which distance education provides personalized education support service nowadays. A distance education system is put forward based on Web usage mining techniques. Through analyzing the access behavior, the frequency, the browsing contents and the staying time of the students, get the general pattern of students access behaviors, and than provide personalized education support service comprehensively according to these analysis.

摘要：Superhydrophobic and superhydrophilic surfaces have been extensively inves- tigated due to their importance for industrial applications. It has been reported, however, that superhydrophobic surfaces are very sensitive to heat, ultraviolet （UV） light, and electric potential, which interfere with their long-term durability. In this study, we introduce a novel approach to achieve robust superhydrophobic thin films by designing architecture-defined complex nanostructures. A family of ZnO hollow microspheres with controlled constituent architectures in the morphologies of 1D nanowire networks, 2D nanosheet stacks, and 3D mesoporous nanoball blocks, respectively, was synthesized via a two-step self-assembly approach, where the oligomers or the constituent nanostructures with specially designed structures are first formed from surfactant templates, and then further assembled into complex morphologies by the addition of a second co-surfactant. The thin films composed of two-step synthesized ZnO hollow microspheres with different architectures presented superhydrophobicities with contact angles of 150°-155°, superior to the contact angle of 103° for one-step synthesized ZnO hollow microspheres with smooth and solid surfaces. Moreover, the robust superhydrophobicity was further improved by perfluorinated silane surface modification. The perfluorinated silane treated ZnO hollow microsphere thin films maintained excellent hydrophobicity even after 75 h of UV irradiation. The realization of environmentally durable promising solution for their long-term irradiations. superhydrophobic surfaces provides a service under UV or strong solar light

摘要：A Z-scheme is a promising approach to achieve broad-spectrum photocatalysis. Integration of TiO2 with another semiconductor with a band gap of -1.0 eV would be ideal to harvest both ultraviolet and visible-near infrared light for photocatalysis; however, most narrow-bandgap semiconductors have straddling band structure alignments with TiO2, constituting an obstacle to forming the Z-scheme for photocatalytic hydrogen production. In this communication, we demonstrate Ag2S as a model system where the energy band upshift of the narrow-bandgap semiconductor that shares an interface with a metal can overcome this limitation. To fabricate the design, we developed a unique approach to synthesize Ag2S-Ag-TiO2 hybrid structures. The obtained ternary hybrid structures exhibited dramatically enhanced performance in photocatalytic hydrogen pro- duction under full-spectrum light illumination. The activities were significantly higher than the sum of those of Ag2S-Ag-TiO2 structures under λ〈 400 nm and λ 〉 400 nm irradiation as well as those of their counterparts under any light illumination conditions.

摘要：On-Line Analytical Processing (OLAP) refers to the technologies that allow users to efficiently retrieve data from the data warehouse for decision support purposes. OLAP queries tend to be complex, often requiring computationally expensive operations such as multi-table joint and aggregation. In the high dimensional DW, we fully materialize the data cube impossibly. In this paper, we propose a novel aggregation algorithm, DHEPHA, to vertically partition a high dimensional dataset into a set of disjoint low dimensional datasets called shell Cube fragments. Using inverted hierarchical encoding indices and pre-aggregated results, OLAP queries are computed online by dynamically constructing cuboids from these Cube fragments. DHEPHA uses the small and their prefix, so it can rapidly retrieve the matching dimension member hierarchical encoding and evaluate the set of query ranges for each dimension, so that it can drastically reduce the multi-table joining effort and even could completely remove one or more join operations. As a result, the method we propose in this paper can greatly reduce the disk I/Os and highly improve the efficiency of OLAP queries.