摘要：Phase transformation of two-dimensional(2D)nanomaterials can lead to significant changes in electronic and optical properties,which enables the development of novel *** strategies for phase engineering of 2D nanomaterials have drawn considerable attention in recent *** review focuses on the state-of-the-art progress in the phase transformation of 2D nanomaterials and their catalytic ***,the basic concepts of phase transformation and the outstanding electronic and optical properties induced by phase transformation are briefly ***,different strategies for achieving phase transformation are discussed in detail and classified into several types based on their characteristics,including(i)doping,(ii)external fields,(iii)optical irradiation,(iv)strain effect,(v)high-energy particle excitation,and(vi)thermal *** applications of 2D nanomaterials in catalysis based on phase transformation have also been ***,a summary of the technical challenges to phase control in 2D nanomaterials and potential opportunities for developing novel applications is presented.

摘要：The development of low-cost,highly active platinum(Pt)-based electrocatalysts for oxygen reduction reaction(ORR)is crucial for widespread applications of fuel *** effective approach lies in alloying Pt with non-noble transition metals to modulate the physicochemical state of the Pt ***,fundamental challenges remain in understanding the structure-performance relationship due to the complexity of composition,crystal type,and surface structure during the alloying *** this study,we synthesized a series of PtCo bimetallic solid solutions with varying ratios using a liquid-phase synthesis *** exploiting the characteristics of solid solutions,the resulting PtCo bimetallic alloy maintains the face-centered cubic crystal structure of pure platinum,minimizing the complexities introduced during alloying and facilitating mechanism ***,under controlled alloy composition and crystal structure,we investigated the dependence of the electrocatalytic activity for the oxygen reduction reaction on the surface strain of the platinum *** S-PtCo-SNPs cathode designed accordingly endows both proton exchange membrane fuel cell(PEMFC)(2.08 W cm^(−2) at 4 A cm^(−2))and Zn-air battery(ZAB)(143.1 mW cm^(−2) at 214.5 mA cm^(−2))with outstanding performance.

摘要：为了进行高拱坝的地震风险分析,引入幂指数函数的形式来描述地震危险性曲线,结合概率地震需求模型和地震易损性曲线函数,推求了概率地震风险分析解析函数。基于此,以实际工程为例,开展了高拱坝-地基体系整体稳定概率地震风险分析。在概率统计框架下,以高拱坝-地基系统整体抗震稳定安全评价为研究目标,在考虑坝基岩体内控制性滑动块体滑裂面力学参数不确定性基础上,构建了概率地震风险分析模型,得到了基于残余滑动位移的高拱坝-地基体系年超越概率曲线。从而给出了设计基准期限内,高拱坝-地基体系整体地震稳定达到不同性能水平的概率,为其在极限地震下的抗震安全评价提供依据,同时为现有基于准则的混凝土坝抗震安全决策转向基于风险概率的安全决策提供科学依据。

摘要：针对重庆忠万高速绿化带滴灌工程的比降大、管道长的复杂条件,基于Darcy-Weisbach公式建立了迭代求解数学模型,并布置室内水力学实验获得实测参数来验证。针对滴管管网设计参数,包括管长、滴头间距、坡比等对出流均匀度的影响,指出在一定的坡比、管长等边界条件下,适当的初始水头、滴头间距参数组合可满足滴灌系统的出流均匀度要求。

摘要：某多层砌体结构房屋墙体受压承载力不足,结合体外预应力加固技术的特点和研究现状,提出一种采用体外预应力卸载砌体结构墙体竖向荷载的方法,从而使墙体受压承载力满足设计要求.该方法施工简单、传力明确、对原结构干扰较小,能够满足墙体加固需要.解决了实际工程中存在的问题,并阐述了该加固方法相比传统加固方法所具有的优势.