Ag~+型配位树脂的制备及对FK506分离纯化的研究

将HZM-3大孔树脂磺化,动态法载银依次获得Ag+-1#、Ag+-2#、Ag+-3#、Ag+-4#、Ag+-5#共5种Ag+型配位树脂,通过它们对FK506的静态吸附与解吸实验优选出了Ag+-3#树脂,其吸附率为77%,解吸率为92%;Ag+-3#树脂与FK506形成络合物的稳定性受溶液极性的影响,在室温下的静态吸附曲线表明,其对FK506的配位吸附符合Langmuir单分子层吸附模型;Ag+-3#树脂配位层析分离FK506,当甲醇:乙酸乙酯(V/V)=50:50,上样量为8mg/m L,流速为1BV/h时,可在4.5倍柱体积内完成整个分离过程,合并不含类似物的收集液,浓缩后在HPLC上检测纯度为98.83%,收率为87.35%,无类似物FK520与2H-FK506检出;乙醇结晶最终产品的纯度达到99.6%以上,样品经过ICP-AES检测,在其检测限内未检测出Ag+。     

Great enhancement in remnant polarization of SrBi4Ti4O15 thin films by A-site doping of Fe3+ ions

SrBi4-xFexTi4O15 (SBFT-x) thin films (x = 0.00, 0.05, 0.08, 0.15) have been synthesized on Pt/Ti/SiO2/Si (100) substrates by sol-gel method. This paper finds that Fe-doping does not change the crystal structure of SrBi4Ti4O15 (SBTi). The coercive filed (Ec) and remnant polarisation (Pr) increase at first, then decrease with the increase of Fe doping content. At a maximum applied field of 229 kV/cm, the 2Pr reaches a maximum value of 91.1 μC/cm2 at x = 0.05 and the corresponding Ec is 72 kV/cm. The 2Pr increases by about 260% and the Ec decreases by about 6%, respectively. Obviously, the ferroelectric property of SrBi4Ti4O15 is greatly enhanced by Fe doping. The fatigue-endurance characteristic of the SBFT-0.05 is not improved. After 1.1×109 read/write cycles at a frequency of 50 kHz, the nonvolatile polarisations (Pnv = P*-P∧) decreased about 48% of its initial value.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser.We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations.The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

与794nm飞秒激光精确同步的无直流背底的1064nm脉冲光的产生

基于非共线光参量放大(NOPA)，以宽带794nm飞秒激光的倍频光为抽运光，以连续的He-Ne激光为信号光，产生了与宽带794nm飞秒激光精确同步的无直流背底的1064nm的脉冲光.实验结果显示该1064nm的光脉冲可作为光参量啁啾脉冲放大系统的抽运激光链的种子光，从而实现用全光学方法实现OPCPA系统抽运光和信号光的精确同步.还将非共线光参量放大器置于经特殊设计的He-Ne激光腔内，也同样成功得到了无直流背底的1064nm的光脉冲.经一次光参量放大后所得到的1064nm光的光谱和空间啁啾特性与非共线光参量放大器置于He-Ne激光腔外时得到的1064nm的光脉冲相同，而其单脉冲能量约为腔外NOPA的10倍. 关键词： 非线性光参量放大 光参量啁啾脉冲放大 时间同步     

A Sensitive Scheme to Observe Weak Photo-Refraction Effects in Some Nonlinear Optical Crystals Pumped by Ultrashort Optical Pulses

We present a sensitive scheme, for the first time to our knowledge, to observe photo-retraction （PR） ettects in some nonlinear optical crystals, e,g. β-BBO, LBO and BIBO, pumped by an intense ultrashort laser pulse chain. These quite weak effects are ＂amplified＂ by sensitive cw intraeavity loss modulation. Our results show that they are repeatable and are dependent on pumping power and wavelength, and their response time ranges from tens of seconds to several minutes. The recorded dynamical transitions between the self-focusing to the self-defocusing （or vice versa） induced by the PR effect may be critically important for us to give more insight into the stability of some cascade nonlinear frequency conversions, e.g. multi-stage optical parametric amplifiers.     

在线分析脱丙烷塔顶中气体组分的气相色谱柱系统研究

 根据生产要求 ,对裂解装置中高压和低压脱丙烷塔顶中工艺气的气相色谱在线监控柱切换流程进行了研究。通过 3个进样器的二次异步进样 ,结合前吹、反吹等技术 ,应用 7根柱子 ,成功地在 6min内实现了对 C2 ' S、丙烷、丙烯、丙炔、丙二烯及 C4' S的在线分离分析。现场应用表明 ,研制的柱切换系统满足工艺监控要求。     

几何问题中的函数值域

在近几年高考中,频繁出现的求直线的斜率和截距、动点坐标、向量夹角、图形面积等参数的取值范围问题,表面看来是几何问题,但其实质可以看作是函数的值域问题.从数量关系来看,需把所求的量用另外一个量表示,建立这两个量之间的函数关系,然后通过求函数的值域,即可得到所求参数的范围.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

A Theoretical and Experimental Research on Terahertz Electro-Optic Sampling at Near-Zero Optical Transmission Point

We report an improved theoretical model to characterize terahertz electro-optic （F,O） sampling detection operating at near crossed-polarizer design by considering the nonzero minimal transmission of polarizers and the polarization purity of laser beam. The proof-of-concept experiments show that the model can give quiet reasonable explanations on many experimental phenomena in THz EO detection, e.g. the modulation depth vs the different optical biases, the noise level from the balance detector vs the input probe beam power, the main origin of the background light and the incomplete cancellation of noise from the laser intensity fluctuation in balanced detection. The terahertz signals and the noises are also measured based on two different EO sampling schemes for comparison. The measured results support our model very well.