摘要：Regulating chemical bonds to balance the adsorption and disassociation of water molecules on catalyst surfaces is crucial for overall water splitting in alkaline *** we report a facile strategy for designing Ni2W4C-W3C Janus structures with abundant Ni-W metallic bonds on surfaces through interfacial *** Ni atoms into the W3C crystals in reaction progress generates a new Ni2 W4C phase,making the inert W atoms in W3C be active sites in Ni2W4C for overall water *** Ni2W4CW3C/carbon nanofibers(Ni2 W4-W3C/CNFs)require overpotentials of 63 mV to reach 10 mA cm^-2 for hydrogen evolution reaction(HER)and 270 mV to reach 30 mA cm^-2 for oxygen evolution reaction(OER)in alkaline electrolyte,*** utilized as both cathode and anode in alkaline solution for overall water splitting,cell voltages of 1.55 and 1.87 V are needed to reach 10 and 100 mA cm^-2,*** functional theory(DFT)results indicate that the strong interactions between Ni and W increase the local electronic states of W *** Ni2W4C provides active sites for cleaving H-OH bonds,and the W3C facilitates the combination of Hads intermediates into H2 *** in situ electrochemical-Raman results demonstrate that the strong absorption ability for hydroxyl and water molecules and further demonstrate that W atoms are the real active sites.

摘要：提出了一类近圆回归轨道的设计方法,解决当飞行任务对星下点有要求时,近圆回归轨道的设计问题。分析了星下点轨迹与轨道参数的关系,概括为当对星下点轨迹有要求时,近圆回归轨道的设计依赖于轨道半径和轨道倾角两个参数的确定。以轨道半径和轨道倾角为未知量依据星下点轨迹要求条件构建了非线性方程组,但直接求解过于复杂,采取迭代的方法解决。编制了MATLAB程序进行设计计算,并将计算结果用软件STK(Satellite Tool Kit)进行仿真。仿真结果显示,该算法能够较好的实现设计目标。

摘要：Objective To optimize the extraction procedure and obtain the maximum total polysaccharide yield from Turpiniae *** Response surface methodology(RSM),combining Plackett–Burman design(PBD),steepest ascent method,and Box–Behnken design(BBD),was *** significant factors contributing to polysaccharide production were determined by *** path of steepest ascent method was performed to rapidly reach the neighborhood of the optimum *** and RSM were applied to further investigate the mutual interaction between the variables and to define the optimal *** The significant factors contributing to polysaccharide production were enzyme concentration,extraction time,and liquid-to-solid *** optimal conditions for maximal TFP were:enzyme concentration of2.8%,extraction time of41min,and liquid-to-solid ratio of27mL/*** experimental yield of3.08%was in good agreement with the model-predicted yield of3.1%under the optimized *** This study was successfully applied to optimize the extraction conditions of Turpiniae Folium polysaccharide,which can contribute to its further production and application.

摘要：传统村落的创意性传承性保护是响应乡村振兴战略的有效道路。识别河南省传统村落的空间格局和影响因素对于河南传统村落的发展规划和体制升级具有重要的现实参考价值。以河南省5批国家级传统村落为研究对象,运用GIS空间分析法,利用核密度估计、热点探测揭示河南国家级传统村落的空间分布特征。结果表明:河南省国家级传统村落的空间分布具有明显的差异性和不均衡性,总体上呈分散分布,小范围内呈集聚分布,且形成了“两核一带”的空间分布格局,其中豫西、豫北为主要核心区,豫南为次核心区,豫西和豫北之间呈带状分布。传统村落空间分异特征的形成受城市经济发展水平、交通便利程度、自然地理环境和社会人文等多方面因素的综合影响。该研究可为河南省国家级传统村落的保护开发和传承利用提供借鉴。

摘要：The special electronic characteristics and high atom usage efficiency of metal-nitrogen-carbon(M-N-C)materials have made them extremely attractive for oxygen reduction reactions(ORRs).However,it is inevitable that hydrogen peroxide(H_(2)O_(2))will be formed via the two-electron pathway in ***,the Cu nanoparticles(NPs)have been encapsulated into Ni doped hollow mesoporous carbon spheres(Ni-HMCS)to reduce the generation of H_(2)O_(2)in *** tests confirm that the introduction of Cu NPs improves the ORR performance *** obtained Cu/Ni-HMCS exhibits a half-wave potential of 0.82 V *** hydrogen electrode and a limited current density of 5.5 mA cm^(-2),which is comparable with the commercial Pt/***,Cu/Ni-HMCS has been used in Zn-air battery,demonstrating a high power density of 161 mW cm^(-2)and a long-term recharge capability(50 h at 5 mA cm^(-2)).The theoretical calculation proposes a tandem catalysis pathway for Cu/Ni multi-sites catalysis,that is,H_(2)O_(2)released from the Ni-N_(4)and Cu-N_(4)sites migrates to the Cu(111)face,on which the captive H_(2)O_(2)is further reduced to H_(2)*** work demonstrates an interesting tandem catalytic pathway of dual-metal multi-sites for ORR,which provides an insight into the development of effective fuel cell electrocatalysts.

摘要：基于运动想象的脑-机接口系统是脑-机接口中的一个主要研究方向,共空间模式(CSP)算法是一种流行的运动想象数据分析特征提取方法。共空间模式的性能依赖于恰当的带通滤波,通常高度依赖于神经生理先验知识。本研究提出一种称为共迭代时空模式(ICSTP)的运动想象时空特征提取方法,该算法用与空域滤波器设计相同的广义特征值问题优化时域滤波器,并给出了算法收敛性的证明。真实脑电数据实验结果表明算法的收敛只需数个循环,且平均正确率高于人工选择时域滤波器的标准CSP方法。

摘要：研究目的:为改善实际工程结构在不确定性条件下的多性能指标,提供一种高效的区间多目标优化方法。创新要点:建立一个目标和约束均为区间不确定性参数函数的区间约束多目标优化模型,提出并实现基于径向基函数、区间分析和非支配排序遗传算法(NSGA-II)的区间多目标优化算法。研究方法:首先,利用区间序关系将每个区间目标转换为同时优化其中点和半径的确定性双目标,利用区间可能度法将区间约束转换为确定性约束,并在此基础上,利用加权法和罚函数法将每个区间目标的约束优化问题转换为相应的无约束优化问题;然后,利用拉丁超立方实验设计和有限元分析构建预测各待优化结构性能指标值的径向基函数;最后,将径向基函数、区间分析法与NSGA-II相结合,快速求出转换后确定性无约束多目标优化问题的所有Pareto最优解,并通过考虑材料不确定性的高速压力机滑块机构设计实例验证该方法的有效性。重要结论:目标和约束均为不确定性参数函数的区间多目标优化模型能有效反映实际工程中同时改善结构多性能指标的需求。基于径向基函数、区间分析和NSGA-II相结合的区间多目标优化算法将传统区间优化模型求解中的嵌套优化过程简化为单层遗传优化过程,大大提高了求解效率,并可获得多目标优化问题的所有Pareto最优解。

摘要：针对扩展卡尔曼滤波(EKF)在线性化过程中会引入误差的问题,采用平淡卡尔曼滤波器(UKF)进行了系统滤波器设计;提出一种构建虚拟观测量的方法,并分析了其噪声特性.虚拟观测量与高精度器件量测量搭配可实现对姿态的校正.以太阳敏感器、微电子机械系统(M EM S)陀螺、磁强计为姿态敏感器件,构建了定姿滤波器并用STK(Satellite T oo l K it)数据进行了仿真.结果表明,所提出方法能有效地提高定姿性能,采用UKF的系统定姿误差与EKF相当,但收敛时间、稳定性要优于EKF.

摘要：非洲雕刻艺术是非洲艺术的重要组成部分,对西方乃至世界艺术的发展起到了极大的推动作用。非洲雕刻艺术的魅力不仅在于其令人耳目一新的外在设计,更重要的是,其背后蕴含的丰富的文化信息。通过重点介绍非洲雕刻艺术的基本含义及特征、非洲雕刻的分类,并挖掘非洲雕刻所反映出的传统宗教信仰、民俗文化、社会意识等文化信息,分析其国际传播情况,旨在增进国人对非洲艺术和文化的了解,推动中非文化交流与合作。

摘要：采用有限元数值模拟手段,分析了锚杆锚索不同布置方式和支护参数等情况下锚杆、锚索与围岩间应力场特征。在此基础上,以淮南顾北煤矿12326煤巷为工程背景,结合实际地质条件设计相应的支护方案。通过无损检测仪器,对实践地点回采巷道锚杆锚索工作载荷进行监测,监测结果表明锚杆锚索工作载荷处于屈服载荷的30%-50%,说明施加的预紧力和锚固方式有效,锚索起到承载围岩作用,锚杆（索）支护设计合理科学。