半导体激光泵浦Nd：YVO4激光器的1.34μm输出特性

报道了半导体激光泵浦Ｎｄ：ＹＶＯ４激光器在１．３４μｍ的输出特性，当入射的泵浦光功率为５１５ｍＷ时，最大１．３４μｍ激光输出功率达１５７ｍＷ，光－光转换效率为３０．５％，研究了激光器的纵模特性及弛豫噪声与泵浦功率的关系，发现不同的纵模具有各自不同的弛豫振荡频率。     

Dynamics of triple-flames in ignition of turbulent dual fuel mixture: A direct numerical simulation study

Pilot-ignited dual fuel combustion involves a complex transition between the pilot fuel autoignition and the premixed-like phase of combustion, which is challenging for experimental measurement and numerical modelling, and not sufficiently explored. To further understand the fundamentals of the dual fuel ignition processes, the transient ignition and subsequent flame development in a turbulent dimethyl ether (DME)/methane-air mixing layer under diesel engine-relevant conditions are studied by direct numerical simulations (DNS). Results indicate that combustion is initiated by a two-stage autoignition that involves both low-temperature and high-temperature chemistry. The first stage autoignition is initiated at the stoichiometric mixture, and then the ignition front propagates against the mixture fraction gradient into rich mixtures and eventually forms a diffusively-supported cool flame. The second stage ignition kernels are spatially distributed around the most reactive mixture fraction with a low scalar dissipation rate. Multiple triple flames are established and propagate along the stoichiometric mixture, which is proven to play an essential role in the flame developing process. The edge flames gradually get close to each other with their branches eventually connected. It is the leading lean premixed branch that initiates the steady propagating methane-air flame. The time required for the initiation of steady flame is substantially shorter than the autoignition delay time of the methane-air mixture under the same thermochemical condition. Temporal evolution of the displacement speed at the flame front is also investigated to clarify the propagation characteristics of the combustion waves. Cool flame and propagation of triple flames are also identified in this study, which are novel features of the pilot-ignited dual fuel combustion.     

36-W diode-pumped continuous-wave 1319-nm Nd:YAG ceramic laser

Continuous-wave output at 1319 nm was obtained from a laser-diode-pumped 1% ceramic Nd:YAG laser. As much as 36.3-W output was obtained under pump power of 290 W, with an optical-to-optical conversion efficiency of 12.5%.     

原子力显微镜法研究方解石(104)面的生长及溶解

研究生物矿化过程及生物矿物的形成机制具有重要的科学意义,这方面的研究不仅有助于我们认识自然,而且还可以指导体外仿生合成具有分级结构的功能性复合材料.原子力显微镜(atomic force microscope,AFM)是微米、纳米尺度上实时观测矿物成核或生长的强有力工具.本文综述了原子力显微镜法研究方解石(104)面生...     

石墨炉原子吸收法测定生物样品中的铊

为建立测定生物样品中铊的石墨炉原子吸收法,通过微波消解,采用基本改进剂,改变石墨炉灰化温度等操作条件,提高了该法的准确度和精密度.结果表明,方法的线性范围为0～100 μg/L;检出限:血为0.10 mg/L;尿为0.02 mg/L;头发为0.20 mg/kg;回收率:血为83.1%～108%;尿为89.6%～105%...     

Borel方向与亚纯函数的唯一性

设f是复平面上的亚纯函数,arg z=θ(0≤θ＜2π)是f的一条Borel方向.如果亚纯函数g和f在包含arg z=θ的角域内IM分担五个不同的值ai∈(C)(i=1,2,3,4,5),则f≡g.