摘要：Electrochemical CO_(2) reduction is a promising technology for solving the CO_(2) emission problems and producing value-added products. Here, we report a hierarchically porous Cu1Au single-atom alloy(SAA) as an efficient electrocatalyst for CO_(2) reduction. Benefiting from the hierarchically porous architectures with abundant vacancies as well as three-dimensional accessible active sites, the as-prepared nanoporous Cu1Au SAA catalyst shows remarkable CO_(2) reduction performance with nearly 100% CO Faraday efficiency in a wide potential range(-0.4 to -0.9 V vs. reversible hydrogen electrode. The in-situ X-ray absorption spectroscopy studies and density functional theory calculations reveal that the Cu-Au interface sites serve as the intrinsic active centers,which can facilitate the activated adsorption of CO_(2) and stabilize the *COOH intermediate.

摘要：The design of highly active and stable catalysts for the oxygen evolution reaction(OER) in acidic media has become an attractive research area for the development of energy conversion and storage technologies. However, progress in this area has been limited by the poor understanding of the dynamic active structure of catalysts under realistic OER conditions. Here, an atomic Co-doped nanoporous Ru O_(2)electrocatalyst, which exhibited excellent OER activity and stability in acidic conditions, was synthesized through annealing and etching of a nanoporous Co-Ru alloy. Operando X-ray absorption spectroscopy results confirmed that the etching strategy produced abundant oxygen vacancies around the metal centers in the atomic Co-doped nanoporous Ru O_(2)electrocatalyst. These vacancies created contracted metaloxygen ligand bonds under realistic OER conditions. The dynamic structural evolution of the synthesized electrocatalyst allowed them to experience lower kinetic barriers during OER catalysis, resulting in enhanced catalytic activity and *** study also provided atomic details on the active structure of the electrocatalyst and the influence of their structural evolution on OER activity.

摘要：建立完整有效的大坝帷幕防渗体系,是保证水库顺利竣工、正常运行的关键。本文以青海省晓龙沟水库为例,提出一种经济可靠的重力坝帷幕灌浆加深方案。采用现场灌浆试验数据结合数值模拟计算,论证了帷幕灌浆加深方案的可行性,并在此基础上分析验证了大坝的渗漏量、渗流分布、扬压力等关键物理力学参数的合理性。该方案能够有效提高帷幕整体性和完整性,当岸坡部分坝基帷幕底界的灌前透水率稍偏大,而坝基渗流、应力满足水库大坝设计要求时,可不再对岸坡坝基帷幕进行加深。研究成果可为类似条件下大坝帷幕灌浆提供指导和参考。

摘要：基于极限平衡法建立了以工程造价为目标的土钉支护结构优化设计模型,采用改进复形法求解,并通过优化后分析进一步揭示了模型参数变化对优化问题的影响。该方法已编制成计算机设计软件,实际工程应用证明是成功的。

摘要：The CoCrFeNiMn high entropy alloy was produced by homogenization, cold rolling and recrystallization. The effects of thermomechanical processing on microstructures and tensile properties at different temperatures were investigated using X-ray diffractometry（XRD）, optical microscopy（OM）, scanning electron microscopy（SEM） and multi-functional testing machine. The results show that dendritic structures in cast alloy evolve into equiaxed grains after being recrystallized, with single face-centered cubic（FCC） phase detected. The most refined alloys, stemming from the highest rolling ratio（40%）, exhibit the highest strength due to the grain boundary strengthening, while the variation of elongation with temperature shows a concave feature. For the coarse-grained alloys, both the ductility and work hardening ability decrease monotonically with increasing temperature. Serrated flow observed at intermediate temperatures is attributed to the effective pinning of dislocations, which manifests the occurrence of dynamic strain hardening and results in the deterioration in ductility. Besides, dimples on the fracture surfaces indicate the typical ductile rupture mode.

摘要：Today s SAN architectures promise unmediated host access to storage. To keep this promise, however, several issues and opportunities raised by SANs must be addressed, including security, scalability and management. Object storage, such as introduced by the NASD work, is a means of addressing these issues and opportunities. RAID using Object-Based Storage Devices is described, about which some issues are discussed and then its performance by queuing model is investigated.

摘要：本文聚焦20世纪初期大西洋两岸的西方艺术史学者在学术讨论中对中国绘画接受程度的转变,并研究了其在动摇古典模式的美学讨论中的地位和作用。方法上的趋同导致了对西方连接历史、美学和史学语境的逻辑的质疑。此外,20世纪最初几十年对世界文化开放的加剧,同样推动了中国绘画新认知的产生。如果说中国绘画展现出另一种绘画参考系的有效性及其内在一致性,那么在艺术史学者中则形成了一种观念,即对于区别或偏离古典规范的表达形式的探索也应该在西方传统的背景下进行。这有利于中国绘画与意大利早期绘画或现当代艺术之间的调和与比较,反过来也为重新解读西方艺术开辟了道路。因此,对欧洲之外文化可能存在的其他美学准则的讨论,在很大程度上促进了关于中国绘画观念的转变,而后者同样对这些讨论作出了贡献。

摘要：A novel series of pyrido[ 1,2-e]purin-4（3H）-one derivatives containing polar substituents on 5＇-position were designed and prepared as potential PDE5 inhibitors. This paper reports the synthetic routes, 1H-NMR data, and the PDE5 inhibitory activities of the target compounds. The polar piperazinyl group contained （on 5＇-position） compound, 3B2, showed the highest activity among the tested derivatives but less potency than sildenafil 1.

摘要：采用了多学科设计优化方法,根据涡流理论建立了倾转旋翼桨叶空气动力学分析模型,利用CATIA,ANSYS和ADAMS等软件分析倾转旋翼桨叶结构动力学特性,采用iSIGHT多学科设计优化软件集成空气动力学和结构动力学分析模型,建立起倾转旋翼桨叶空气动力学/结构动力学多学科设计优化系统,进行多学科设计优化研究.并以倾转旋翼机XV-15的桨叶为算例,进行设计优化,结果表明提出的倾转旋翼桨叶空气动力学/结构动力学多学科设计优化方法是可行和有效的.

摘要：A new challenge has been brought by the rapid development of information technology to medical teaching, and the teaching reform of the medical education in China should be deepened for attaining a development. The core of deepening medical teaching reform is to break the traditional teaching model （i.e. giving a lecture）, and create a better classroom teaching situation by making full use of the modern teaching methods. In B-learning, the effective combination of the traditional teaching method＇ s advantages with the E-learning in a pure technical environment is advocated. In the task-driven teaching, a teaching design is made by students in a real or simulated real environment. In this paper, the effective combination of B-learning with the task-driven teaching model is introduced, so that the better teaching effect is achieved.