液晶自适应光学的研究进展

概述了中科院长春光学精密机械与物理研究所(长春光机所)在液晶自适应光学方面的研究进展。针对液晶自适应光学技术存在的能量利用率低和校正频率慢的两大国际难题,液晶自适应光学研究组采取了一系列有效措施,不但攻克了能量利用率低的难题,且在校正频率方面也取得了质的飞跃。目前,系统能量利用率已从最初的5%提高到85%,基本和变形镜自适应光学系统的能量利用率相当;校正频率也从5 Hz提高到140 Hz,接近了校正大气湍流的实用化水平。利用该研究成果,分别研制了针对中科院国家天文台2.16 m望远镜和长春光机所1.2 m望远镜的液晶自适应光学系统并对恒星进行了有效校正,使1.2 m望远镜对恒星的分辨能力提高至约3倍衍射极限。     

表面活性剂含量对全息聚合物分散液晶光栅电光特性的影响

研究了含表面活性剂Actyflon-G04的全息聚合物分散液晶透射光栅的表面形貌和电光特性,通过理论分析得出驱动电压和膜的锚定能及表面自由能的关系.实验结果表明,在Actyflon-G04含量为4wt%-8wt%时光栅相分离程度高,相界面平滑,聚合物层的致密度增加.光栅的衍射效率达到96%,接近理想值.实现了在提高光栅衍射效率的同时降低驱动电压,使光栅的电光特性得到改善.     

2 ns, 351 nm激光黑腔靶受激Raman散射实验研究

 介绍了在神光Ⅱ装置上开展的长脉冲2 ns,351 nm激光与黑腔靶相互作用的实验，报道了受激Raman散射光时间分辨谱图及能量测量的实验结果。长脉冲2 ns激光注入小腔靶（Ø700 mm×1 250 mm）时，激光辐照缝靶产生的SRS光能量是激光与全腔靶作用产生的SRS光能量的1.3倍。在2 ns激光与不同尺寸黑腔靶作用的情况下，激光辐照小腔靶产生的SRS光能量比标准腔靶(Ø800 mm×1 350 mm)产生的SRS光能量高1.6倍。由于激光功率密度下降，2 ns激光打靶SRS散射光要弱于短脉冲1 ns激光打靶，但持续时间稍长。实验结果表明：长脉冲2 ns激光与标准腔靶相互作用时，等离子体“堵腔效应”比较严重，标准腔靶尺寸不再合适。     

Low-field electron emission from pinaster-like MoO2 nanoarrays as two-stage emitters

Low-field electron emission is obtained from the pinaster-like MoO2 nanoarrays. The turn-on field of the pinasterlike MoO2 nanoarrays is found to be as low as 2.39 V/μm with the current density of 10μA/cm2. The enhancement factor is extracted to be 3590 from the Fowler-Nordheim plot. These excellent emission properties are attributed to the special structure of the pinaster-like MoO2 nanoarrays and confirmed by the calculation in the frame of the two -stage model. Our results show that the pinaster-like MoO2 nanoarrays are promising candidate in realizing field emission displays.     

温度对全息聚合物分散液晶光栅形貌及电光特性的影响

采用光敏预聚物、向列相液晶和光引发剂混合物体系,在不同温度条件下制备全息光栅.利用红外光谱、光学显微镜、He-Ne激光器对预聚物和光栅进行测试.实验结果表明,光栅的衍射效率随制备温度的升高先增加后减小.对实验结果进行分析,发现它与光聚合反应体系的特性有很好的对应关系,同时深入探讨了制备温度对光栅形貌及电光特性的影响.     

高效液相色谱-电喷雾串联质谱法对氧化条件下缬草素降解产物的结构及氧化动力学研究

建立了评价缬草素在氧化条件下稳定性的系统方法。采用高效液相色谱-电喷雾串联质谱(HPLC-ESI MS/MS)法对缬草素在氧化条件下(H2O2)的降解产物进行分离,并对主要降解产物进行结构鉴定,样品经Agilent Extend-C18分离,以乙腈-0.25%乙酸水溶液为流动相,梯度洗脱,质谱条件为电喷雾离子源(ESI),正离子模式检测。在上述条件下,共鉴定出4个主要降解产物,其中1个由标准品对照而得,4个化合物的结构母核均为缬草醛类成分。利用HPLC测定缬草素在H2O2中不同时间点的含量变化,经计算缬草素在H2O2中的变化符合一级动力学方程,10%的原型产物发生降解的时间为0.5 h。实验从定性和定量两方面揭示了缬草素的降解机制和降解规律,可为缬草素或含有缬草素的中药制剂的进一步研究与应用提供依据。     

Force-Field Derivation and Atomistic Simulation of HMX/Graphite Interface and Polycrystal Systems

Interface is the key issue to understand the performance of composite materials.In this work,we study the interface between octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX) and graphite,try to find out its contribution to mixture explosives.The work starts from the force-field derivation.We get ab initio based pair potentials across the interface,and then use them to study the interface structural and mechanical properties.A series of large scale molecular dynamics simulations are performed.The structure evolution,energy variation and elastic/plastic transformation of interface and polycrystal systems are calculated.The desensitizing mechanism of graphite to HMX is discussed.     

527nm激光辐照盘靶背向散射能量测量

在星光Ⅱ激光装置上,测量了脉宽1ns、能量40-110J的527nm激光在不同条件下辐照Au盘靶、Al盘靶的背向散射能量。结果表明:激光辐照Au盘靶时．在聚焦条件下背向散射能量约占打靶激光能量的7．8％;在束匀滑条件下背向散射能量份额下降到6.2％左右,证明了束匀滑可有效抑制背向散射。对比Au盘靶、Al盘靶背反能量与打靶激光能量关系曲线,可以看出背向散射能量与打靶激光能量基本上成线性关系。 Au and Al disk target were irradiated with -1 ns, 40-110 J, 527 nm laser at Xingguang-Ⅱ facility. The backscattered lights by laser-produced plasma were studied experimentally. The results are in troduced in this paper. Backscattered light energy is 7.8% of laser energy when laser is focused on Au disk target; when laser beam is smoothed, it is 6.2%. The comparison shows that laser smoothing can restrain backscattered light efficiency. The experimental results :also show that there is a linear relation between backscattered light energy and the laser energy.