FTIR光谱仪中基于定镜调整的动镜运动控制研究

动镜是FTIR光谱仪中唯一不断运动的部件,动镜的匀速运动性能以及动镜与定镜的准直性好坏影响干涉效果和光谱图质量,直接制约着仪器的精度和分辨率,对仪器整体指标起着重要作用。文章围绕FTIR光谱仪中干涉仪动镜运动的匀速性以及其与定镜的准直性展开研究,使用相位检测技术对定镜的姿态作出动态调整以补偿动镜与定镜间的倾斜夹角,并且设计了具有磁悬浮特点的动镜支撑系统。文章采用改进的模糊PID控制算法实现动镜运动速度的精确调节,对该控制方案从硬件设计和算法上实现。结果表明所研发的动镜运动控制系统具有足够的精度和实时性,能够保证FTIR光谱仪中干涉仪所需的准直性及动镜匀速性的要求。     

带有非吸收窗口的高性能InGaAs/AlGaAs量子阱激光二极管

为了解决限制近红外单发射区InGaAs/AlGaAs量子阱半导体激光二极管失效阈值功率提升的腔面光学灾变损伤问题,研制了一种带有Si杂质诱导量子阱混杂非吸收窗口的新型激光二极管,并对其性能进行了测试分析.首先,对于带有非吸收窗口的二极管,在其谐振腔上方前后腔面附近的窗口区域覆盖50 nm Si/100 nm SiO2组...     

Raman of indigo on a silver surface. Raman and theoretical characterization of indigo deposited on silicon dioxide-coated and uncoated silver nanoparticles

Raman, surface-enhanced Raman scattering, and shell isolated nanoparticles-enhanced Raman scattering techniques were used to study the indigo–nanoparticle interaction nature. Silver nanoparticles were employed with and without a silicon dioxide spacer inert layer. The SERS spectral profile, obtained using silver nanoparticles, is different from the Raman one, which led to the proposition that the indigo–silver interaction is in the range of intermolecular interactions. SERS spectral reproducibility suggests identical organization and orientation of the analyte on the metal surface. The shell isolated nanoparticles enhanced Raman scattering spectrum of indigo, obtained by using silicon dioxide coated silver nanoparticles resulted similar to its Raman spectrum. This result indicates that the indigo structure is chemically unmodified by the silicon dioxide-coated silver surface. From the shell-isolated nanoparticles-enhanced Raman scattering experiments, the electromagnetic mechanism is proposed as the reason for the spectral enhancement. Theoretical calculations allow one to infer both the indigo–silver surface interaction nature and the orientation of indigo on the surface.     

铝和银在铱（111）宽范围吸附的稳定性、原子构型及电子特性研究

利用第一性原理密度泛函理论研究了铝和银在铱的111面的宽范围吸附特性。基于密度泛函理论计算了覆盖度在0.11ML到2.00ML的结构稳定性、原子构型及平均结合能。对于铝原子在铱111面的吸附,最稳定的结构是铝原子覆盖度为0.5ML位于密堆六方空位（hcp-hollow）,相应的结合能为-4.68eV;对于亚层铝原子的吸附,最稳定结构是铝原子覆盖度为1.00ML时位于octahedral位置,相应的结合能为-5.28eV。对于覆盖度为2.00ML的满覆盖度混合结构的表层及亚层吸附,最稳定结构是Al位于六方密堆及八方密堆位置,相应的结合能为-4.70eV。这意味着当铝原子以满覆盖度吸附在铱的111面上时,趋向于在铱的111面的亚层形成化学键,而非吸附于表层。相比于铝吸附在铱111面,银的吸附特性呈现出很大的不同,面心位置更为稳定,在覆盖度为0.25ML时其结合能为3.89eV,略微高出密堆六方位置处3.88eV的结合能。     

矿山尾矿中微量银元素快速检测方法的研究

针对矿山尾矿中微量银元素测定的技术难题,提出了一种基于超短光路原理的能量色散X荧光能谱快速检测的方法。提高元素测量分辨率,提高样品分析效率,降低光管功率,延长仪器使用寿命。能谱系统优化了滤片以及探测器屏蔽物等设计,准直器采用对X射线基本无散射的聚四氟乙烯,达到微量银元素的检测要求。实际尾矿测试中,银的检出限达到0.1 mg·kg-1,RSD在0.1%～2.6%之间,准确度在87%～115%之间。对比尾矿、原矿及精矿的检测实验,证明了在能量色散X荧光能谱中引入超短光路设计方法,能够提升系统峰/本底比,满足微量银元素的检测要求。     

A 12.1-W SESAM mode-locked Yb:YAG thin disk laser

Pumped by a 940 nm fiber-coupled diode laser, a passively mode-locked Yb:YAG thin disk oscillator was demonstrated with a semiconductor saturable absorber mirror(SESAM). 12.1 W mode-locked pulses were obtained with pulse duration of 698 fs at the repetition rate of 57.43 MHz. Measurement showed that the beam quality was close to the diffraction limit.     

Induction time of silver nanoparticles precipitation: Experiment and modeling

This paper describes the measurement of induction time in precipitation of silver nanoparticles at different temperatures and supersaturations, and models it with Smoluchowski's coagulation theory. Silver nanoparticles are synthesized by reaction of silver nitrate with hydrazine in the presence of sodium citrate as stabilizer. The rate of association between clusters is found to depend on temperature and their sizes. The activation energy for the association between two clusters and interfacial tension of silver nanoparticles were also estimated. The results also show that induction time decreases with increasing supersaturation and temperature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

天基激光武器系统的发展

介绍了天基激光武器系统的概念、组成、应用和关键技术,分析了激光对目标的杀伤程度,并给出了相应的参考阈值。针对系统的关键问题提出一些解决方法,包括高能激光器的研制和种类,大口径反射镜研制技术和结构形式,以及天基目标捕获跟踪瞄准(ATP)系统精度的影响因素和提高精度的方法。通过对天基激光武器系统发展的研究,为该系统的进一步发展和精度的提高提供研究方向和理论基础。