摘要：The selective hydrogenation of quinolines to 1,2,3,4-tetrahydroquinolines(py-THQ) and its derivatives has attracted a considerable amount of attention as they show great versatility in many pharmaceuticals, agrochemicals, and fine chemicals. Over the past few decades, great breakthroughs have been achieved in the controlled synthesis of efficient heterogeneous catalysts used for the selective hydrogenation of functionalized quinoline compounds, which allow one to correlate the structure-property relationships. In this review, we will summarize the recent significant progress achieved in this field covering the synthetic strategies, microstructural and chemical features, catalytic performance, and internal relationships. State-of-the-art noble metal-based single(Pd, Pt, Ru, Rh, Ir and Au) and bi/multi-metallic catalysts(RuCu, AuPd, and PdNi) are first introduced, followed by a summary of earth-abundant metal-based catalysts(Co, Fe, Ni, and Cu). Finally, the dehydrogenation of N-heterocycles is introduced to form a reversible hydrogenation/dehydrogenation system for H2 storage, which can be employed in a liquid organic hydrogen system. Furthermore, the reaction mechanism and future research direction in these areas are also discussed. This review will deepen our understanding of the catalytic transformation of N-heterocycles and provide guidance for researchers on the rational design of catalysts.

摘要：H‐ZSM‐5 zeolite is a typical catalyst for methanol‐to‐olefins(MTO)*** the performance of zeolite catalysts for MTO conversion is related to the actual location of acid sites in the zeolite framework,the catalytic roles of the acid sites in different pore channels of the H‐ZSM‐5 zeolite are not well *** this study,the MTO reaction network,involving the aromatic cycle,alkene cycle,and aromatization process,and also the diffusion behavior of methanol feedstock and olefin and aromatic products at different acid sites in the straight channel,sinusoidal channel,and intersection cavity of H‐ZSM‐5 zeolite was comparatively investigated using density functional theory calculations and molecular dynamic *** results indicated that the aromatic cycle and aromatization process occurred preferentially at the acid sites in the intersection cavities with a much lower energy barrier than that at the acid sites in the straight and sinusoidal *** contrast,the formation of polymethylbenzenes was significantly suppressed at the acid sites in the sinusoidal and straight channels,whereas the alkene cycle can occur at all three types of acid sites with similar energy barriers and ***,the catalytic performance of H‐ZSM‐5 zeolite for MTO conversion,including activity and product selectivity,can be regulated properly through the purposive alteration of the acid site distribution,viz.,the location of Al in the zeolite *** study helps to elucidate the relation between the catalytic performance of different acid sites in the H‐ZSM‐5 zeolite framework for MTO conversion,which should greatly benefit the design of efficient catalyst for methanol conversion.

摘要：Obtaining a detailed understanding of the surface modification of supports is crucial;however,it is a challenging task for the development and large-scale fabrication of supported electrocatalysts that can be used as alternatives to Pt-based catalysts for the oxygen reduction reaction(ORR).In this study,commercial silicon carbide(SiC)was modified through surface oxidization(O-SiC)to support the use of Pd nanoparticles(Pd NPs)as electrocatalysts for *** obtained Pd/O-SiC catalysts exhibited better ORR activity,stronger durability,and higher resistance to methanol poisoning than that exhibited by commercial Pt/*** role of the support in enhancing the ORR performance,especially the oxidization of SiC surfaces,was discussed in detail based on the experimental characterizations and density functional theory *** underlying mechanism of the superior ORR performance of Pd/O-SiC catalysts was attributed to the charge transfer from SiC_(x)O_(y)to Pd NPs on the surfaces of SiC and the strong metal–support interactions(SMSIs)between Pd and SiC_(x)O_(y).The charge transfer enhanced the ORR activity by inducing electron-rich Pd,increased the adsorption of the key intermediate OOH,and decreased the Gibbs free energy of the critical ORR ***,SMSIs enhanced the ORR stability of the Pd/O-SiC *** study provided a facile route for designing and developing highly active Pd-based ORR electrocatalysts.

摘要：北京老城是东方古都的杰出代表,北京向来重视历史文化的传承,但在现代化进程中,古都历史文化保护仍然面临来自社会、经济、城市定位及交通方式变化等诸方面的压力和挑战。针对东方古都的杰出代表——北京老城,设计通过对北京老城东方营城智慧挖掘探索的研究主线,强调中轴线统领作用的“一轴带两翼”总体布局。在保护与发展并重的规划引导下,设计凝练了北京老城何以杰出的营城智慧——山水格局的自然调和、都城规制的礼制大成、理想城市的市井生活,揭示了北京老城历史传承的重大价值。在此基础上,通过传统城市设计与数字化城市设计技术方法的综合运用,设计进一步诠释了北京老城形态构成的内在规律特征,形成了“营城八法”的北京老城空间解析及价值体系,并最终指导了北京老城空间形态及环境的设计营造。

摘要：Electrocatalytic ammonia synthesis under mild conditions is an attractive and challenging process in the earth’s nitrogen cycle,which requires efficient and stable catalysts to reduce the *** N2 activation and reduction overpotential of different Ti3C2O2-supported transition metal(TM)(Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Mo,Ru,Rh,Pd,Ag,Cd,and Au)single-atom catalysts have been analyzed in terms of the Gibbs free energies calculated using the density functional theory(DFT).The end-on N2 adsorption was more energetically favorable,and the negative free energies represented good N2 activation performance,especially in the presence Fe/Ti3C2O2(﹣0.75 eV).The overpotentials of Fe/Ti3C2O2,Co/Ti3C2O2,Ru/Ti3C2O2,and Rh/Ti3C2O2 were 0.92,0.89,1.16,and 0.84 eV,*** potential required for ammonia synthesis was different for different TMs and ranged from 0.68 to 2.33 *** possible potential-limiting steps may be involved in the process:(i)hydrogenation of N2 to*NNH and(ii)hydrogenation of*NH2 to *** catalysts can change the reaction pathway and avoid the traditional N–N bond-breaking *** also simplifies the understanding of the relationship between the Gibbs free energy and overpotential,which is a significant factor in the rational designing and large-scale screening of catalysts for the electrocatalytic ammonia synthesis.

摘要：历史城区作为承载中华文化的生命有机体,不仅承担着保护与发展的使命,还面临着传统风貌特色亟待强化、社区生活环境急需改善、整体景观环境有待提升等问题。以太原府城城市设计为例,以“历史保护”和“环境提升”两大突破口为破局之道,紧扣历史人文线、社区生活线、景观环境线3条贯通性主线,分别遴选出具有前置性、关键性、高显示度的核心工作和项目抓手,并建立“核心问题—贯通性主线—专题研究—设计干预—基本思路”的城市设计工作路线,以盘活历史城区格局,为太原府城实现“唐风晋韵·锦绣龙城”的美好图景提供核心空间框架和长效导控依据,并为历史街区的活力再生与韧性发展提供普适性示范和参考。

摘要：风电齿轮箱不同轮系间存在的耦合调制现象干扰了实际故障诊断,为此,针对两级行星一级平行结构的齿轮箱提出一种考虑级间耦合调制的现象学模型。首先,在风电齿轮箱振动信号幅值、频率解调分析基础上,定义了多级传动下的级间串联调制特性,并提出幅值-频率级间串联调制模型;通过构造多级调幅信号和调频信号,在频谱和解调谱中对串联调制特性进行仿真分析,并提出耦合调制特性边带能量指标用于模型评价;设计了与现场齿轮箱具有相同结构的缩比齿轮箱实验台,并在正常与故障状态下进行实验、现场联合分析,验证级间串联调制模型的有效性。结果表明:频率耦合调制现象在四种状态下尤为明显,其耦合调制特性边带能量分别为1.02、1.04、1.18、1.25。本模型所反映的齿轮箱级间耦合调制现象是齿轮箱本身所有,不会因齿轮箱的状态而发生改变,本模型为提高风电齿轮箱故障诊断准确性提供参考。

摘要：The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N‐heterocycles is a *** this study,Ru_(2)P/AC effectively promoted reversible transformations between unsaturated and saturated N‐heterocycles affording yields of 98%and 99%,***,a remarkable enhancement in the reusability of Ru_(2)P/AC was observed compared with other Ru‐based *** to density functional theory calculations,the superior performance of Ru_(2)P/AC was ascribed to specific synergistic factors,namely geometric and electronic effects induced by P.P greatly reduced the large Ru‐Ru ensembles and finely modified the electronic structures,leading to a low reaction barrier and high desorption ability of the catalyst,further boosting the hydrogenation and acceptorless dehydrogenation processes.

摘要：目的提升钛合金异型环轧制时的填充效果,提高成形精度,确定轧制型腔对环件成形质量的影响。方法以TC4合金斜I型截面环件为研究对象,设计了开式与闭式2种轧制型腔,对该环件的轧制过程进行了研究。建立了斜I型截面环件的有限元模型,基于有限元模拟结果全面分析了不同轧制型腔对环件等效应变、温度分布以及型腔填充效果的影响规律。结果与开式型腔相比,闭式型腔轧制的环件具有更优的等效应变和温度分布,型腔填充情况也明显更优,填充率在96%以上,进而确定了闭式型腔的轧制方式。采用设计的闭式型腔进行了环件轧制试验,试验环件尺寸与模拟结果吻合良好,误差在0.3%以内,同时组织性能均能够满足生产要求。结论选择闭式型腔轧制可以有效提升钛合金异型环轧制时的填充效果,提高成形精度,提升环件成形质量。

摘要：面向对流层飞艇起降过程复杂、气象适应能力弱等特殊性,传统基于文本的运行概念分析方法具有设计一致性较差、设计无法有效追溯、验证困难等局限性。基于此,提出了基于模型的系统工程的对流层飞艇运行概念设计方法。首先,建立系统用例与利益攸关者需求的关联关系,保证了设计可追溯性。然后,基于活动图、时序图与内部块图建立对流层飞艇运行场景模型,详细梳理了飞艇运行的执行逻辑与外部交互关系。通过执行状态机对飞艇运行概念模型进行验证,并进一步补充完善利益攸关者需求。最后,通过执行状态机验证了该无人飞艇系统能够满足任务飞行、飞行控制和应急情况响应等利益攸关者的需求。