PM567-Doped solid dye lasers based on PMMA

Polymers are a kind of attractive hosts for laser dyes due to their high transparency in both pumping and lasing ranges and superior optical homogeneity. In this paper solid dye samples based on polymethyl methacrylate (PMMA) doped with different concentrations of 1, 3, 5, 7, 8 -pentamethyl-2, 6-diethylpyrromethene-BF$_{2 }$ (PM567) are prepared. The absorption, fluorescence and lasing spectra of the samples are obtained. Wide absorption and fluorescence bands are obtained and a red shift of the maxima of the lasing emission spectra is observed. With the second-harmonic generation of Q-switched Nd:YAG laser (532\,nm, $\sim $20\,ns) pumping the samples longitudinally, the slope efficiencies of the samples are obtained. There is an optimal dye concentration for the highest slope efficiency when the pumping energy is lower than some typical value ($\sim $250\,mJ), and the highest slope efficiency 35.6{\%} is obtained in the sample with a dye concentration of $2\times10^{ - 4}$\,mol/L. Pumping the samples at a rate of 10Hz with a pulse energy as high as 200\,mJ (the fluence is 0.2\,J/cm$^{2})$, the output energy drops to one-half of its initial value after approximate 15500 pulses and the normalized photostability is 5.17\,GJ/mol. A kind of solid dye laser which could have some applications is built.     

Optical phase conjugation by resonant degenerate four-wave mixing in liquid phase medium

In this paper, frequency-doubled Nd:YAG laser's phase conjugation has been investigated experimentally using resonant degenerate four-wave mixing (DFWM). The iodine solution was used as resonant medium. In this way, the energy of the DFWM phase conjugation beam arrived at 43μJ/pulse while the total pump beam's energy reached 8mJ/pulse. The relation between the pulse energy of the DFWM phase conjugation beam and that of the pump beam was investigated. We also measured the optical field distributions of pump beam and DFWM phase conjugation beam, from which it can be noticed that the DFWM phase conjugation can improve the laser beam quality. At the same time, we observed the influence of the pump beam's disturbance on the DFWM signal.     

模糊加工时间排序问题的性质

本文根据实际背景提出加工时间为三角形模糊数的排序问题,分析这个问题的性质,并就进一步研究提出几个思考。     

光场电离类镍氪等离子体参数研究

计算了１０ＨＺ、１４０ｆｓ、５０ｍＪ、８００ｎｍ圆偏振光场电离产生的类镍氪等离子体参数,着重研究了电离激光强度对等离子体参数的影响,并由此确定了适合于电子撞激发类镍氪３１．９ｎｍ超紫外（ＸＵＶ）激光系统的最佳激光强度。     

受激布里渊散射相位共轭腔及腔内光学参量振荡器

利用受激布城渊散射相位共轭特性和Ｑ开关特性组成Ｎｄ：ＹＡＧ激光谐振腔,代替传统激光器全反镜和调Ｑ装置,获得能量１００ｍＪ,脉宽１３ｎｓ的线偏振相位共轭激光输出,相应的激光器总体转换效率为０．４７％,同时将单共振ＫＴＰ光学参量振荡器置入腔内,得到波长１．５７μｍ、能量１５ｍＪ的参理振荡激光,实验证实了受激布城渊散射相位共轭腔内光学参量振荡器运行的可行性。     

圆偏振光场电离电子能量分布的计算

以准静态隧道电离理论为基础,建立了描述圆偏振光场电离电子能量分布的简单模型,与现有的理论计算及实验结果的比较表明,该模型数学推导简单,物理意义明显,可用于研究高电子温度和（或）较低电子密度的光场电离等离子体参数。     

单向砌体填充墙激波管试验和动力行为分析

为研究远场爆炸荷载作用下单向砌体填充墙的动力行为及其失效破坏机理,首先,基于研发的压缩空气驱动大截面（3 m×3 m）激波管开展了两面不同厚度单向实心砌体填充墙的面外加载试验,获得了作用在墙体表面的反射超压荷载时程、墙体面外挠度时程及墙体的变形失效模式。其次,建立了激波管精细化有限元模型,提出了砌体墙简化微观有限元建模方法,以及扩展砖块的Riedel-Hiermaier-Thoma材料模型和接缝的内聚力接触模型参数取值计算方法,对激波管中的压力传播以及试验墙体面外动态响应和损伤破坏开展了数值模拟。最后,基于爆炸荷载作用下单向砌体填充墙面外抗力方程和等效单自由度模型对试验墙体中心点面外挠度时程进行预测。结果表明：减小墙体高厚比可以增大框架拱推力,从而显著提升墙体的抗爆性能,厚105 mm的墙体在经历1次激波管试验后发生倒塌,而厚235 mm的墙体在经历6次激波管试验后仅有轻微损伤;墙体表面反射超压荷载时程的试验和数值模拟结果均为均布脉冲型荷载,且两者吻合很好,验证了激波管设计和激波管精细化有限元模型的合理性;数值模拟和理论预测的墙体动力行为与试验结果吻合较好,可为砌体填充墙抗爆评估与分析...     

一步电沉积法合成Au-rGO及其在DNA传感器中的应用

采用一步沉积法将金纳颗粒和还原氧化石墨烯成功地负载FTO导电玻璃上,形成了Au-rGO三维网状结构。并通过XRD、Raman、SEM、TEM对该结构进行了形貌表征和分析。采用EIS、SWV等电化学方法实现了对突变p53基因片段的高灵敏性、高选择性检测,得到检测灵敏度为5.11μA·M~(-1)·cm~(-2),检测限为2.19×10~(-14)M(S/N=3),检测结果良好。本文尝试将杂交后的电极在含有电化学活性物质的电解液中直接测试,省去了电化学活性物质吸附的步骤,以达到简化实验减少误差的目的。     

低抖动Marx发生器设计与实验

提出并设计了一种Marx发生器线路,将电路模拟和实验验证结果与传统的Marx线路进行了比较,结果表明,所设计的线路通过保证Marx后级开关上的过电压幅值,来保证开关可靠击穿并减小开关自击穿所需时间,从而减小Marx发生器的抖动和增大工作范围。在此线路基础上,设计了一种用于直线感应加速器脉冲功率系统的Marx发生器,该发生器采用正负双极性直流充电,使用低抖动的场畸变火花隙开关作为脉冲形成开关,最大储能16.87 kJ,最高输出电压450 kV,在一定工作状态下可以达到亚纳秒级的时间抖动。     

The dissociation pathways of N2+ in intense femtosecond laser fields

Using a neutral N2 beam as target,this paper studies the dissociation of N2+ in intense femtosecond laser fields(45 fs,～1×10 16 W/cm 2) at the laser wavelength of 800 nm based on the time-of-flight mass spectra of N + fragment ions.The angular distributions of N+ and the laser power dependence of N + yielded from different dissociation pathways show that the dissociation mechanisms mainly proceed through the couplings between the metastable states(A,B and C) and the upper excited states of N2+.A coupling model of light-dressed potential energy curves of N+2 is used to interpret the kinetic energy release of N+.