长、短周期光纤光栅退火实验研究

光纤光栅技术是光纤通信领域继光纤放大器之后的一个里程碑 ,由此产生的全光纤光子线路及其集成将对光纤通信的发展产生巨大的推动作用。获得性能稳定的光纤光栅具有重要的意义。介绍了长、短周期光纤光栅的光学特性及退火特性     

线性啁啾光纤光栅色散补偿性能的数值分析

对线性啁啾光纤光栅的色散补偿性能进行了数值分析。结果表明 ,啁啾光栅时延曲线的纹波大小和线性度是影响其色散补偿性能的两个重要因素。对高斯型耦合系数分布光栅而言 ,更长的光栅将具有更佳的色散补偿性能     

Characterization of signs change of nonlinear refraction in ZnSe based on a modified double 4f imaging system with a phase object

Signs change of nonlinear refractive index in ZnSe is observed by employing a modified double 4f imaging system at the wavelength of 800 nm using picosecond pulses with different pulse energies. This process results from the competition of the bound electronic nonlinear refraction and the free carrier refraction. At low intensity, positive nonlinear refraction is obtained, which is attributed to bound electrons. As the increase of laser beam intensity, the nonlinear refractive index become small, and changes to negative. This is ascribed to free carriers generated by two-photon absorption. Additionally, the nonlinear refractive index of bound electron and the refractive index change of free carrier are determined unambiguously by a simple method.     

Liquid chromatography tandem mass spectrometry method for determination of bisoprolol in human plasma using d5‐bisoprolol as the internal standard

A simple, reliable and sensitive liquid chromatography tandem mass spectrometry (LC‐MS/MS) protocol was developed and validated for quantification of bisoprolol in human plasma. The sample was pretreated with a simple procedure of protein precipitation and an isotope‐labeled d5‐bisoprolol was used as internal standard. The chromatographic separation was performed on a Capcell Pak C₁₈ MG III column (100 mm × 2.0 mm, 5 µm). The protonated ion of the analyte was detected in positive ionization by multiple reaction monitoring mode. The mass transition pairs of m/z 326.3 → 116.3 and m/z 331.3 → 121.3 were used to detect bisoprolol and the internal standard, respectively. Linearity, accuracy, precision, recovery, matrix effect, dilution test and stability were evaluated during method validation over the range of 0.5–100 ng/mL. The validated method was successfully applied to analyze human plasma samples in a bisoprolol bioavailability study. Copyright © 2009 John Wiley & Sons, Ltd.     

Yalongenes A and B,Two New Cembranoids with Cytoprotective Effects from the Hainan Soft Coral Sarcophyton trocheliophorum Marenzeller

Two new cembranoids, yalongenes A ( 1 ) and B ( 2 ), were isolated from the South China Sea soft coral Sarcophyton trocheliophorum Marenzeller . Their structures were elucidated by detailed spectroscopic analysis (IR, MS, and NMR) and by comparison with a related model compound. Yalongenes 1 and 2 were evaluated for their cytoprotective effects on SH‐SY5Y cell injury induced by H₂O₂ in vitro, and the result showed that only compound 1 had a significant cytoprotective activity at the concentration of 1 μM .     

Microwave-Promoted Rapid Synthesis of 1-Aryl-1,2,3-Triazoles

1, 2, 4- and 1, 2, 3-triazole derivatives have found wide applications as plant growth regulators1, bactericides and medical fungicides2, insecticides3 and in dyeing and color development4.One of the general routes of synthesis of 1-aryl-1, 2, 3-triazoles was to treat aryl azides with a-keto phosphorus ylides in dry refluxing benzene for 0.5 to 2 days5. Herein we report, for the first time, a very quick and simple, microwave-promoted synthesis of 1-aryl-1, 2, 3-triazoles 3 from aryl azides 1 an…     

Topographies of Organized Monolayer of α-Amylase Observed by Atomic Force Microscopy

Preparing the organized ultrathin film of proteins is the key to developing of protein-based molecular devices such as biosensors. In the past, the organized molecular layers were fabricated by the means of Langmuir-Blodgett (LB), which utilized the amphipathy of molecules. Molecular deposition (MD) which is based on the electrostatic interaction between the charged substrates and oppositely charged absorbate is a new and versatile method for preparing organized self-assembled ultrathin film…     

Laser-enhanced thermal effect of moderate intensity focused ultrasound on bio-tissues

For avoiding extra-damage to healthy tissues surrounding the focal point during high intensity focused ultrasound (HIFU) treatment in medical therapy, to reduce the ultrasonic intensity outside the focal point is expected. Thus, the heating processes induced by moderate intensity focused ultrasound (MIFU) and enhanced by combined irradiation of laser pulses for bio-tissues are studied in details. For fresh bio-tissues, the enhanced thermal effects by pulsed laser combined with MIFU irradiation are observed experimentally. To explore the mechanisms of these effects, several tissue-mimicking materials composed of agar mixed with graphite powders are prepared and studied for comparison, but the laser-enhanced thermal effects in these mimicking materials are much less than that in the fresh bio-tissues. Therefore, it is suggested that the laser-enhanced thermal effects may be mainly attributed to bio-activities and related photo-bio-chemical effects of fresh tissues.     

强激光加载下锡材料微喷颗粒与气体混合回收实验研究及颗粒度分析

冲击波在金属材料自由面卸载时,材料表面会形成微颗粒向外喷射,这是材料表面一种特殊的破坏形态.在内爆压缩和高压工程领域的相关物理过程中,微喷射颗粒是引起界面混合现象的重要来源,会直接影响后期的混合状态和压缩过程.而微颗粒的尺寸、形态、运动速度等是开展微喷混合过程理论和数值模拟研究的重要参数.由于实验中动态诊断的难度较大,目前已获取的微喷颗粒尺寸及分布数据十分有限.基于神光Ⅲ原型激光装置,本文设计并开展了强激光驱动冲击加载,锡材料微喷颗粒经过气体区混合后,低密度泡沫材料对微颗粒进行回收分析的实验研究.通过对微喷颗粒回收样品的X光电子计算机断层扫描分析和图像重建,获得了两个典型加载压强条件下与气体混合后微喷颗粒的三维图像,通过与真空实验条件下回收微喷颗粒图像的对比分析,对混合后的微喷颗粒分布形态有了初步的认识;测量统计了回收颗粒尺寸与数目,并通过分析,给出了微喷颗粒尺寸的双指数分布规律.     

气相色谱-串联质谱法测定人参和黄芪中7种毒杀芬残留量

建立了人参和黄芪中毒杀芬代表性单体残留量的检测方法。选择7种指示性毒杀芬单体为检测品种,样品用环己烷-丙酮(9:1,v/v)加速溶剂萃取法提取,经弗罗里硅土固相萃取柱净化后,以气相色谱-电子轰击离子源串联质谱(GC-EI-MS/MS)在多反应监测(MRM)模式下进行测定。在人参和黄芪两种中药材样品基质,0.005、0.01和0.1 mg/kg 3个加标水平条件下,7种毒杀芬单体的回收率为72.4%～105%,相对标准偏差为0.96%～10.4%;方法的检出限(S/N=3)为0.2～1.7 μg/kg,均符合农药残留检测要求。该方法提取效果好,检测灵敏度高,适用于人参和黄芪中7种毒杀芬残留量的检测。