High-intensity femtosecond laser absorption by rare-gas clusters

The energy absorption efficiency of high-intensity (～10^{16}W/cm^2) femtosecond laser pulses in a dense jet of large rare-gas clusters has been measured. Experimental results show that the energy absorption efficiency is strongly dependent on the cluster size and can be higher than 90%. The measurement of the ion energy indicates that the average ion energies of argon and xenon can be as high as 90 and 100keV, respectively. The dependence of the average energy of the ions on the cluster size is also measured. At comparatively low gas backing pressure, the average ion energies of argon and xenon increase with increasing gas backing pressure. The average ion energy of argon becomes saturated gradually with further increase of the gas backing pressure. For xenon, the average ion energy drops a little after the gas backing pressure exceeds 9 bar (3.2×10^5 atoms/cluster). The result showing the existence of a maximum average ion energy has been interpreted within the framework of the microplasma sphere model.     

形貌可控表面修饰纳米级tio2的合成与表征

纳米tio2;超临界co2;非水解;形貌可控;表面修饰;纳米棒     

Near crack line elastic-plastic analysis for a finite plate loaded by two pairs of antiplane point forces

I.IntroductionThenearcracklineanalysismethodhasbeengreatlyimprovedbyYill'2].In[l,21,theimprovednearcracklineanalysismethodhasbeenusedtoinvestigateamodeIllcrackinanelastic-perfectlyplasticsolid.Andthesmallscaleyieldingconditionshavebeencompletelyabandoned,andcompletelynewandprecisesolutionsoftheelastic-plasticfieldsofamodeillstationarycrackandamodelillquasi-staticallygrowingcrackwithremotealltiplaneshearinginanelastic-perfectlyplastic'materialhavebeenobtained,respectively.In[3]weanalyzedthene…     

四面体无定型无氢非晶碳膜的制备及其摩擦学性能研究

采用磁过滤阴极真空弧系统分别在硅片[Si(100)]、W18Cr4V高速钢和Cr18Ni9不锈钢基体上沉积了一系列sp3键含量较高的四面体无定型无氢非晶碳膜(ta-C),研究了所合成薄膜的结构、硬度、附着强度和摩擦磨损性能,考察了基体和薄膜厚度对薄膜摩擦系数的影响,简要分析了相应ta-C膜的失效机理.结果表明,在高速钢基体上沉积的ta-C膜的显微硬度为76 GPa,结合力Lc值达42 N,具有优良的摩擦学性能,其摩擦系数为0.12,且摩擦系数可以在16 000 r范围内保持稳定.     

赝卤素阴离子工程在钙钛矿太阳能电池中的应用研究进展

金属卤化物钙钛矿太阳能电池已经能够实现25.7%的认证光电转化效率，接近于晶硅太阳能电池26.7%的最高认证效率。众所周知，ABX3钙钛矿材料的晶体结构组分工程在实现高效和稳定的器件方面发挥着关键作用，尤其是近几年受到研究人员广泛关注的X位卤素阴离子组分工程。最近，研究人员在引入赝卤素阴离子作为钙钛矿晶体的掺杂组分、前驱体添加剂、薄膜后处理材料、电荷传输材料、界面钝化剂以及改性剂等方面开展了多项研究工作，结果证明赝卤素离子修饰是提高器件效率和稳定性的重要策略。本综述详细对比和总结了目前可用于钙钛矿太阳能电池的多种类型的赝卤素离子，并对其影响钙钛矿晶体薄膜形貌、光电特性、载流子迁移特性和器件光伏特性及稳定性等方面的深入机理和作用本质进行了深入总结。同时，本文还对目前尚未被探索开发的赝卤素离子进行了展望和分析，以期在未来研究中能有效促进钙钛矿太阳能电池光伏特性的提升。