A wideband tunable phase shifter based on orthogonal optical single-sideband

We present a novel technique to generate an orthogonally polarized optical single sideband （OSSB） generated by a tunable bandpass filter （TBF）. When the OSSB passes through the other polarization modulation （PolM） which is polarization dependent, the phase shift of the optical carrier and first-order sideband is different under different bias. As a result, a wideband tunable phase shifter is realized by adjusting the bias applied to the polarization modulator.     

Photonic generation of amplitude-and phase-modulated microwave signals with frequency and modulation bit-rate tunability

A photonic approach for the generation of an amplitude- and phase-modulated microwave signal with tun-able frequency and modulation bit-rate is proposed and demonstrated. Two coherent optical wavelengths are generated based on external modulation by biasing a Mach-Zehnder modulator (MZM) at the minimum transmission point to generate ±1-order optical sidebands while suppressing the optical carrier. The two sidebands are sent to a circulator and are then spectrally separated by a fiber Bragg grating notch filter. With one sideband being amplitude-modulated at another MZM and the other being phase-modulated at a phase modulator, a frequency-tunable amplitude-and phase-modulated microwave signal is generated by beating the two sidebands at a photodetector. The proposed technique is investigated theoretically and experimentally. As a result, a 20-GHz amplitude-modulated, 20-GHz phase-modulated, and 25-GHz amplitude-and phase-modulated microwave signals with tunable modulation bit-rate are experimentally generated.     

结直肠癌组织中K-ras基因突变的毛细管电泳检测

通过对PCR扩增的76例结直肠癌组织及癌旁正常组织DNA基因组共152个样本纯化变性后,采用毛细管电泳-激光诱导荧光检测(CE-LIF)结合单链构象多态性(SSCP)分析方法检测了人结直肠癌组织及癌旁正常组织中K-ras基因第12/13位密码子突变。所检测的76例结直肠癌患者中有30例患者存在基因突变,并对异常片段进行测序验证,测序证实以碱基G→A点突变为主。结果表明所建立的CE-LIF技术结合SSCP分析检测K-ras基因突变的方法高效、快速、灵敏、准确,适合于临床上大样本结直肠癌中K-ras基因突变分析,对选择抗结直肠癌药物有一定的指导作用。     

基于混合导光型光子晶体光纤的波分解复用器研究

设计了一种基于混合导光型光子晶体光纤的波分解复用器,该波分解复用器同时具有折射率导光型光子晶体光纤和带隙导光型光子晶体光纤的特点,可用于稀疏型波分复用系统中.设计的稀疏型波分解复用器由一段三芯光子晶体光纤组成,通过填充不同折射率的材料.形成了混合导光型光子晶体光纤.根据耦合模原理,在临近的波导中,当传播常数相等时,模式之间发生强烈耦合.能量在波导之间交替.由于填充的材料折射率不同,使得光功率在两个小同的波长上发生耦合,构成了两个不同响应波长的光滤波器.通过选择合适的光纤长度,使得在光纤的输出端,不同波长的光从不同的波导输出,实现波分解复用的功能.采用全矢量有限元法分析了光纤传输特性,计算了不同波长光的耦合长度.采用光束传播法仿真发现,长度为4.3 mm的光纤能实现波长为1.31μm和1.55μm光的解复用.     

达罗他胺中间体合成中杂质的发现和结构表征

达罗他胺是治疗前列腺癌的重要药物,在进行其合成工艺研究时,在第一步Suzuki偶联和第二步水解脱保护反应中,发现并纯化得到3个杂质A、B和C,其中杂质A和B来自第一步反应,杂质C来自第二步反应.通过高分辨质谱(HRMS)、核磁共振氢谱(¹H NMR)和核磁共振碳谱(¹³C NMR)表征方法,确定了杂质A和B的结构,分别为初始反应原料化合物2的脱硼酸频哪醇酯产物和初始反应原料化合物1的双偶联产物;借助HRMS、¹H NMR、¹³C NMR、¹H-¹H COSY、¹H-¹³C HSQC、¹H-¹³C HMBC和¹H-¹H NOESY方法确定了中间体化合物3和杂质C的准确结构,对其形成机理和规避方法也进行了讨论分析.     

小型宇宙射线探测仪的模拟和测量

介绍了一款小型宇宙射线探测仪。该仪器具有宇宙射线科普演示功能,主要用于实时测量μ子射线并显示计数,以及长时间尺度下（年）稳定地对不同角度的次级宇宙线通量进行监控记录。简要地展示了探测器的硬件构造和探测效率的模拟计算。探测仪单个探测器的探测效率为93.1%,两个探测器符合测量的探测效率为86.6%。根据探测器的计数率以及模拟计算的探测效率,估计了次级宇宙射线垂直地面方向的通量,为J=29±3 m-2 sr-1 s-1。另外,利用该宇宙射线探测仪,测量了兰州市区的次级宇宙射线的天顶角分布。其结果很好地满足I（θ）=IH+I₀ cosα θ经验公式,其中的角度依赖参数α=2.42±0.52。A small cosmic ray device is introduced in this paper.It has the demonstration function for popularization of science,and can be used mainly to display the μ counts in a real-time measurement,and to monitor the secondary cosmic ray flux at different angles in a very long time scale (years).We briefly show the hardware of the device and the detecting efficiency calculation by simulation.The detecting efficiency for one detector of the device is 93.1%,and the detecting efficiency is 86.6% for the coincidence measurement of two detectors.Based on the count rate by the detector and the simulated efficiency,the secondary cosmic ray flux perpendicular to the ground surface is measured,which is J=29±3 m-2sr-1 s-1.Moreover,with an application of the device,we measured the angular distribution of the secondary cosmic ray rate in Lanzhou City.The resulting angular distribution agrees well with the empirical formula as I(θ)=IH+I₀ cosα θ,in which the parameter for the angle-dependence is α=2.42±0.53.     

高效阴离子交换-脉冲安培法测定化妆品中葡萄糖酸锌含量

建立了高效阴离子交换-脉冲安培法测定化妆品中葡萄糖酸锌的含量.样品用水超声提取后,离心取上清液过On Guard Ⅱ RP柱除去疏水性化合物,再经CarboPac PA1和CarboPacPA20保护柱分离,脉冲安培检测,葡萄糖酸锌在0.1～5.0mg/L范围内线性关系良好(r2=0.9999),加标回收率在98.9～107.7％之间,方法检出限为0.042mg/L,对应样品中检出限为4.2mg/kg,方法简单,灵敏度高.     

颜色可调的高荧光CdTe量子点的水相合成

以亚碲酸钠为碲源,硼氢化钠为还原剂,一步合成了巯基丁二酸(MSA)稳定的CdTe量子点.研究了反应液pH值、镉与碲的摩尔比及镉与巯基丁二酸的摩尔比等实验条件对CdTe量子点体系荧光量子产率的影响,并用荧光光谱、X射线粉末衍射及透射电子显微镜等对其进行了表征.结果表明,CdTe量子点具有闪锌矿结构,形貌呈球状;在pH=1...     

活性炭-离子液体凝胶电致动膜材料制备及性能研究

本文通过湿法涂膜和热压复合的方法,制备了基于活性炭-离子液体凝胶的电致动膜材料。使用电化学循环伏安法和原位激光位移传感器分别测定了不同活性炭含量对电致动膜材料的界面电容和电致动位移性能的影响。结果显示膜材料的界面电容和电致动位移性能随着活性炭含量增加而增加。