摘要：The exploitation of competent electrocatalysts is a key issue of the broad application of many promising electrochemical processes,including the hydrogen evolution reaction(HER),the oxygen evolution reaction(OER),the oxygen reduction reaction(ORR),the CO_(2) reduction reaction(CO_(2)RR)and the nitrogen reduction reaction(NRR).The traditional searches for good electrocatalysts rely on the trial-and-error approaches,which are typically tedious and *** the past decades,some fundamental principles,activity descriptors and catalytic mechanisms have been established to accelerate the discovery of advanced ***,it is time to summarize these theory-related research advances that unravel the structure-performance relationships and enables predictive ability in electrocatalysis *** this review,we summarize some basic aspects of catalytic theories that are commonly used in the design of electrocatalysts(e.g.,Sabatier principle,d-band theory,adsorption-energy scaling relation,activity descriptors)and their ***,we briefly introduced the fundamental mechanisms and central challenges of HER,OER,ORR,CO_(2)RR and NRR electrocatalysts,and highlight the theory-based efforts used to address the challenges facing these electrocatalysis ***,we propose the key challenges and opportunities of theory-driven electrocatalysis on their future.

摘要：The large‐scale application of proton exchange membrane water electrolysis technology requires the development of high‐performance oxygen evolution electrocatalysts with as little iridium(Ir)as ***‐based double perovskite oxides(A_(2)B’IrO_(6);A=alkaline,alkaline‐earth,or rare‐earth elements;B’=transition metal or rare‐earth elements)represent a class of oxides with great potential to replace the commercial catalyst IrO_(2).However,the structural evolution of Ir‐based double perovskite oxides in electrolytes is incompletely understood,and foundational knowledge of the design principle of the“ideal”material is *** this work,we report the unexpected phenomenon of instant Ir leaching from Ir‐based double perovskite oxides in acid under non‐catalytic conditions and discuss the implications of this phenomenon for mechanism investigation and material *** well‐known Ir‐based double perovskite oxides,such as Ba_(2)PrIrO_(6) and Sr_(2)YIrO_(6),undergo instantaneous Ir leaching when they come into contact with acidic *** Ir‐leaching process is found to be non‐persistent and non‐thermodynamically determined,and its extent is correlated with the leaching of other B’‐site elements in the perovskite *** on this observation,we revisit the Ir dissolution‐precipitation process for surface IrO_(x) formation during the perovskite‐electrolyzed oxygen evolution reaction,emphasizing the non‐negligible role of Ir species owing to acid corrosion in the ***,we modify a screening protocol for low‐Ir oxygen evolution electrocatalysts and propose an instant acid corrosion test as an indispensable process to evaluate the structural stability of potential catalysts.

摘要：The development of efficient oxygen evolution electrocatalysts with reduced noble metal uses is a critical challenge for the deployment of various advanced energy conversion ***,a series of lanthanide-contained 6H-perovskites with a formula of Ba3LnIr2〇9(Ln=lanthanides)are investigated as oxygen evolution electrocatalysts,whose active subunits(i.e.,face-sharing Ir〇6 dimers)can be regulated by the lanthanides in terms of catalytic *** using density functional theory(DFT)calculations,we establish the theoretical trend in activity for Ba3LnIr2〇96H-perovskites,the activity of which is correlated with the difference of adsorption free energy(△G〇-△Goh)between O*and OH*reaction *** further establish a volcano curve between△Go—△Goh and the calculated 0 p-band center Among the Ba3LnIr2〇96H-perovskites,Ba3Lalr2〇9 locates at the peak of volcano curve,and correspondingly is the most active electrocatalyst due to the optimal 0 p-band property.

摘要：Z-scheme photocatalytic system has been regarded as a popular field of research in photoelectrochemical(PEC)water *** the many obstacles facing a Z-scheme photocatalytic system,the analysis methods of interfacial Z-scheme charge transfer still remain a significant ***,in this study,CdS/Ti-Fe_(2)O_(3)heterojunction photoanodes are elaborately designed to explore the charge-transfer behavior in PEC water *** this study,photophysical measurements,including the Kelvin probe measurement,surface photovoltage spectroscopy(SPV),and transient photovoltage spectroscopy(TPV),are used to monitor the migration behavior of photogenerated charges at the interface electric field of CdS/Ti-Fe_(2)O_(3)Z-scheme heterojunction *** Kelvin probe and SPV measurements demonstrate that CdS/Ti-Fe_(2)O_(3)interfacial driving force favors the rapid transfer of photoexcited electrons to *** double-beam strategy based on TPV indicates that more electrons of Ti-Fe_(2)O_(3)are combined with the holes of CdS owing to the intensive interface electric *** results of these measurements successfully prove the Z-scheme migration mechanism of CdS/Ti-Fe_(2)O_(3)*** from the desirable charge transfer at the interface electric field,CdS/Ti-Fe_(2)O_(3)photoanodes exhibit superior photocatalytic oxygen evolution reaction performance compared with that of pure Ti-Fe_(2)O_(3).The photocurrent density of the 25CdS/Ti-Fe_(2)O_(3)photoanode reaches 1.94 mA/cm^(2) at 1.23 V versus reversible hydrogen electrode without excess cocatalyst,and it is two times higher than that of pure Ti-Fe_(2)O_(3)***,an outstanding strategy is provided in this study to prove the Z-scheme charge-transfer mechanism of photocatalytic systems in PEC water splitting.

摘要：快速断路器可实现短路故障的快速切除,对保证电力系统安全稳定运行具有重要意义。针对一种快速响应、高速运动的新型液压操动机构,建立液压操动机构、传动系统和灭弧室之间的耦合关系,开展液-机-气联合仿真研究,分析不同操作功对动触头运动特性、液压缸缓冲特性和灭弧室反力特性的影响规律,在此基础上,对传动系统应力分布进行计算,对存在破坏风险的零部件提出改进策略,确定试验样机设计方案。研究结果表明:操作功对分闸速度影响明显,确定机构活塞杆侧作用面积为3160mm^(2),分闸速度提升至13.63m/s,触头机械分离时间缩短至4.45 ms,满足快速开断需求。随着机构操作功的提升,机构缓冲力峰值和灭弧室压气反力峰值提升明显,造成部分传动件应力值超标,通过优化液压操动机构缓冲性能以及传动件结构,设计出满足机械强度要求的传动系统。研究成果指导研发了操动机构试验样机,试验结果满足快速开断要求。

摘要：氢因具有高热值、资源丰富和环境友好等优点,被认为是推动全球能源系统脱碳转型的强大动力.基于可再生能源的电解水制氢技术是实现碳中和目标的重要途径,该技术亟需开发低成本、高活性和高稳定性的电解水催化剂.钙钛矿氧化物具有高容忍度的晶体结构、灵活的元素组成和可调变的电子结构,是开发新型电催化剂的理想材料.此外,许多基于钙钛矿氧化物的研究还揭示了电催化剂中涉及的一些催化关键问题,如构效关系、电子结构调控作用、催化机理以及催化剂的动态结构演化等,使钙钛矿氧化物逐渐成为推广科学理论的理想模型催化剂.虽然人们已经在性能优化策略(如元素掺杂、纳米结构工程、缺陷调节)、应用环境(如酸性或碱性介质中)、所含元素(如钴基、铱基和镍基钙钛矿氧化物)等方面对此类催化剂进行了详细总结,但对其催化时所涉及的诸多关键科学问题却缺乏系统讨论.本文总结了钙钛矿氧化物在电催化水裂解反应方面的研究进展,尤其对近期引起关注的关键科学问题进行了详细讨论.首先回顾了钙钛矿氧化物在催化领域的发展历程,随后介绍了钙钛矿氧化物在元素组成与晶相结构方面的多样性.在深入探讨了钙钛矿氧化物中电子特性与催化性能之间的构效关系后,列举了几种代表性的活性描述符(即eg轨道填充数、B-O键共价性、O 2p带中心位置和电荷转移能),分析了各自的适用范围与局限性.重点研究了钙钛矿型电催化剂在水裂解过程中的催化机理和结构演变,强调了原位表征技术在监测动态结构信息和识别关键活性物种方面的重要性.最后,展望了钙钛矿型催化剂应用于电解水技术中的机遇和挑战,提出了此类催化剂的未来发展方向:(1)探索更为理性的材料设计策略;(2)发展更先进的制备技术;(3)揭示更深层次的催化/失活机制;(4)开发更能满足工业需求的高性能催化剂.

摘要：文章依托石门山明洞、稠下一号线明洞、大横明洞填土压力计算测试工程实例,通过考虑路堑偏压式与半路堑单压式两种结构形式,进行了现场测试与理论公式计算,获取了一定数量的双线铁路明洞隧道典型截面位置计算模式不定性随机变量ζ的样本值。采用A-D法检验随机变量ζ的分布概型,获取了ζ的统计特征,再通过统计不定性计算对其进行了修正,得到了土压力计算模式不定性ζ的统计特征。结果表明,ζ的均值为1.065,变异系数为0.127,服从正态分布。该研究结果将明洞土压力计算模式不定性的适应性由单线隧道推广到双线隧道,对基于可靠度的隧道结构设计规范修订有重要意义。

摘要：文章依托国道318线米拉山隧道,开展高海拔寒区隧道凝灰岩变形及力学特征研究。基于对隧道径向变形及围岩压力进行现场监测的结果,表明土体变形较大,围岩应力不能得到及时控制,现有的设计与施工方案无法满足隧道安全要求,需要及时对其调整;通过对实测数据分析,采用弥散裂缝模型分析米拉山隧道凝灰岩裂隙岩体特征,确定REV尺度后进行隧道岩体卸荷试验,结果表明,凝灰岩地段围岩大变形主要由产状为170°∠88°的节理组影响;通过采用超前支护增加节理面抗剪强度以及缩短台阶距离,利用掌子面的约束作用降低卸荷量等措施后,有效地保障了米拉山隧道顺利贯通。研究成果可为类似施工中采取相应措施控制围岩大变形、保障隧道顺利通过不良地质带提供了依据。

摘要：某热电公司电厂一期装设2×300 MW国产引进型亚临界燃煤火电机组。一期1号、2号机组分别于2005年和2006年正式投运,并在2009年进行了供热改造,然而改造后其供电煤耗率依然较高。为积极响应国家节能减排号召,该热电公司电厂基于原有的设备状况、供热能力、热负荷以及预测新增的热负荷,以通流改造、扩大一抽供热能力为基准,对高压供热系统、中压供热系统、汽汽换热器相关系统、疏水系统、回热抽汽系统及减温水系统等子系统进行了基于能量匹配的改造,旨在提升能源利用率,增加经济效益。本次改造将达到节约能源、改善环境,提高经济效益、环境效益、社会效益的目的。

摘要：为研究某供热机组改造后回热系统设备运行的可行性,对设备进行适应性校核,选取高压加热器、低压加热器、凝汽器和除氧器进行性能核算。结果表明:高压加热器壳侧强度校核满足改造参数的要求,但是由于壳侧设计压力的提高,需要重新对壳侧进行水压试验;低压加热器的热力校核与壳侧强度校核满足改造参数要求,但是低压加热器蒸汽流速增加,可能出现管束振动风险;凝汽器热力校核与强度校核结果均为安全;改造后除氧器基本满足参数要求,但是存在一定的振动风险。