摘要：Developing highly active alloy catalysts that surpass the performance of platinum group metals in the oxygen reduction reaction(ORR)is critical in ***-based single-atom alloy(AuSAA)clusters are gaining recognition as promising alternatives due to their potential for high ***,enhancing its activity of AuSAA clusters remains challenging due to limited insights into its actual active site in alkaline ***,we studied a variety of Au_(54)M_(1) SAA cluster catalysts and revealed the operando formed MO_(x)(OH)_(y) complex acts as the crucial active site for catalyzing the ORR under the basic solution *** observed volcano plot indicates that Au_(54)Co_(1),Au_(54)M_(1),and Au_(54)Ru_(1) clusters can be the optimal Au_(54)M_(1) SAA cluster catalysts for the *** findings offer new insights into the actual active sites of AuSAA cluster catalysts,which will inform rational catalyst design in experimental settings.

摘要：Ruthenium(Ru)serves as a promising catalyst for ammonia synthesis via the Haber-Bosch process,identification of the structure sensitivity to improve the activity of Ru is important but not fully explored *** present here density functional theory calculations combined with microkinetic simulations on nitrogen molecule activation,a crucial step in ammonia synthesis,over a variety of hexagonal close-packed(hcp)and face-center cubic(fcc)Ru ***{2130}facet exhibits the highest activity toward N_(2) dissociation in hcp Ru,followed by the(0001)monatomic step *** other hcp Ru facets have N_(2) dissociation rates at least three orders ***{211}facet shows the best performance for N_(2) activation in fcc Ru,followed by{311},which indicates stepped surfaces make great contributions to the overall *** hcp Ru{2130}facet and(0001)monatomic step sites have lower or comparable activation barriers compared with fcc Ru{211}facet,fcc Ru is proposed to be more active than hcp Ru for N_(2) conversion due to the exposure of the more favorable active sites over step surfaces in fcc *** work provides new insights into the crystal structure sensitivity of N_(2) activation for mechanistic understanding and rational design of ammonia synthesis over Ru catalysts.

摘要：Fischer-Tropsch synthesis （FTS） is an increasingly important approach for producing liquid fuels and chemicals via syngas-that is, synthesis gas, a mixture of carbon monoxide and hydrogen-generated from coal, natural gas, or biomass. In FTS, dispersed transition metal nanoparticles are used to catalyze the reactions underlying the formation of carbon-carbon bonds. Catalytic activity and selectivity are strongly correlated with the electronic and geometric structure of the nanoparticles, which depend on the particle size, morphology, and crystallographic phase of the nanoparticles. In this article, we review recent works dealing with the aspects of bulk and surface sensitivity of the FTS reaction. Understanding the different catalytic behavior in more detail as a function of these parameters may guide the design of more active, selective, and stable FTS catalysts.

摘要：Sintering inhibition of a catalyst at high temperatures is a challenge during heterogeneous catalysis. In this paper, we report that hexagonal boron nitride(h-BN) is an optimal material for anti-sintering γ-Al_(2)O_(3)-supported Pt nanoparticles(NPs) originating from the high thermal conductivity of h-BN. The high thermal conductivity of h-BN ensures maximal heat dissipation from Pt NPs to γ-Al_(2)O_(3),thereby causing both Ostwald ripening and particle coalescence of Pt NPs to be decelerated at elevated *** of Pt NP sintering is also shown in the reducible TiO^(2-)supported Pt NPs with the help of h-BN. The proposed anti-sintering strategy using thermal management is universal, providing new insight into the design of anti-sintering materials and structures for a wide range of applications in heterogeneous catalysis.

摘要：The evolution of temperature field of the continual motion induction cladding and the depth of heat affected zone are studied in this study.A three-dimensional finite element model for the point type continual induction cladding is established to investigate temperature distributions of fixed and motion induction cladding *** novel inductor is designed for cladding of curved *** modeling reliability is verified by the temperature *** influence of process parameters on the maximum temperature and the generation and transfer of heat are *** calculation is performed to its melting rate to verify the temperature distribution and *** results show that a good metallurgical bond can be formed between the cladding layer and *** melting rate gradually falls from the top of the cladding layer to the substrate,and the grain size in the substrate gradually *** heat affected zone is relatively small compared to integral heating.

摘要：韩书力先生通过独特的视角、以独创的"黑画"即黑地水墨画这种艺术表现形式与语言,向世人展现了雪域高原的人文、地貌、大美景物和对西藏、对西藏人民深深的热爱。他对西藏传统唐卡绘画艺术进行深入研究和创新,形成其特有的开拓性、包容性、前瞻性的治学特点,独具匠心的画风尤具艺术魅力和学术贡献,使他成为当今西藏艺术学界极富开创性的学者之一。文章主要展现了韩书力先生四十年来在西藏的艺术探索历程和对艺术的感悟与思考。

摘要：对不同内收缩段设计的高超声道流场进行了数值仿真研究,考查了下壁面水平倾角对进气道各性能参数特别是再起动特性的影响。结果表明,减小进气道不起动流场大规模分离区尾部所在下壁面的水平倾角,可以显著提高不起动流场的性能,大幅降低再起动马赫数,但也带来内收缩段长度增加,起动流场性能降低的缺点。为兼顾两者性能,提出了一种新的内收缩段下壁面设计方案,该设计前段采用凹面收缩段,后段接以水平倾角更小的平直段。与原型相比,新设计的长度不变,起动流场的性能波动较小;而再起动马赫数则由9.4降为8,再起动特性改善效果明显。

摘要：上海世博会车载系留气球光电平台集成了多种对工作温度有严格要求的高精密光学设备,设备工作环境复杂,平台重量、功耗等技术指标约束严格。本文采用Sinda/Fluint软件建立了光电平台及载荷设备的热模型,根据计算结果对球载光电平台及其核心设备进行了有针对性的热设计,采用主动热控与被动热控相结合的方法,使整个平台满足热设计指标。实测结果表明,仿真结果与实际值吻合较好,光电平台各设备运行良好。

摘要：质量功能展开理论(Theory of Quality Function Deployment, QFD)和发明问题解决理论(Theory of Inventive Problem Solving, TRIZ)在工程领域已得到广泛应用,但在解决工程问题时存在各自的短板。本研究运用QFD理论与TRIZ理论的集成模型,让两种方法取长补短,帮助工程师发现关键问题,有效解决问题,为技术创新提供新思路。以燃气轮机机匣的改良方案设计为案例,经过需求分析、搭建质量屋、矛盾分析和方案产出等阶段,设计非对称结构机匣装配方案。通过QFD与TRIZ集成应用,可以识别需改进的关键技术参数,并对难以解决的矛盾问题,产生启发解决方案。

摘要：本文推广了传统的余项补偿方法并将其应用于多层差分格式的设计中 .由此不仅可以设计出高精度的多层差分格式 ,并且能有效的控制格式的耗散与色散效应以满足不同数值模拟的需要 .