摘要：针对传统声束的衍射极限问题,如何构建具有更高分辨率的聚焦声场,是实现超分辨声成像和声操控领域的重大挑战之一.本文在考虑成像分辨率同时兼顾声场可控制性,提出了一种基于粒子群优化算法的多频超振荡超分辨聚焦声场设计方法.基于常规换能器声场的衍射效应,利用半波带法设计中心频率菲涅耳透镜,并以中心频率为基准在换能器带宽范围内设置多频信号来构建超振荡声场,进一步通过粒子群算法对多频声束的振幅和相位进行优化,在远场构建了焦域半径能够小于中心频率半波长的超振荡声场,还发现其尺寸小于最高频率声场的所形成焦域半径,进一步证明其焦域半径随着中心频率和超振荡频率数的增大而减小.研究结果为可控超分辨声聚焦提供了一种简便易行的方法.

摘要：本文主要以水泥厂风管固定支架工程设计为研究对象,对支架顶部荷载计算和支架结构构建进行计算分析,并对支架施工图设计中的关键因素和存在的主要问题进行分析,为水泥厂风管支架设计提供理论依据。

摘要：本文以工程实例进行阐述,分析了轻钢结构厂房加固工作的重要性,并结合多年工作经验,为加固厂房的设计工作提供了优化建议,为后续轻钢结构厂房建设,提高其荷载能力奠定理论基础。

摘要：为了研究盾构法、顶管法、定向钻法等非开挖工艺下的海塘大堤保护范围,本文从三种非开挖施工工艺对海塘的影响机理、影响范围分析及保护范围界定三个方面论述,并确定了上海地区三种施工工艺下海塘堤的纵向及横向保护范围。

摘要：为保障施工期间海塘安全稳定,文章研究了定向钻施工对海塘渗流稳定的影响,结合上海地区某穿堤工程案例,提出了穿堤处防渗处理措施。分析了定向钻施工对大堤变形影响,根据计算结果防汛大堤沉降可控制在允许范围内。研究成果对类似穿堤工程具有一定的借鉴意义。

摘要：Alloyed nanoparticles with core-shell structures provide a favorable model to modulate interfacial interaction and surface structures at the atomic level,which is important for designing electrocatalysts with high activity and ***,core-shell structured Pd3M@Pt/C nanoparticles with binary PdM alloy cores(M=Fe,Ni,and Co)and a monolayer Pt shell were successfully synthesized with diverse *** these,Pd3Fe@Pt/C exhibited the best oxygen reduction reaction catalytic performance,roughly 5.4 times more than that of the commercial Pt/C catalyst used as *** significantly enhanced activity is attributed to the combined effects of strain engineering,interfacial electron transfer,and improved Pt *** functional theory simulations and extended X-ray absorption fine structure analysis revealed that engineering the alloy core with moderate lattice mismatch and alloy composition(Pd3Fe)optimizes the surface oxygen adsorption energy,thereby rendering excellent electrocatalytic *** researches may use this study as a guide on the construction of highly effective core-shell electrocatalysts for various energy conversions and other applications.