解吸法校准微量溶氧仪

基于气体溶解定律,提出了校准微量溶氧仪的解吸方法,设计制造了解吸法溶解氧分析仪检定装置,通过理论计算确定了检定装置的技术指标及溶氧水的测量不确定度,并通过实验验证了该方法的可行性。     

利用N型半导体纳米材料抑制单量子点的荧光闪烁特性

利用N型半导体纳米材料氧化铟锡(ITO)作为单CdSe/ZnS量子点的基质来抑制单量子点的荧光闪烁特性. 实验采用激光扫描共聚焦显微成像系统测量了单量子点荧光的亮、暗态持续时间的概率密度分布的指数截止的幂律特性, 并与直接吸附在SiO₂玻片上的单CdSe/ZnS量子点的荧光特性进行比较. 研究发现处于ITO中的单量子点比SiO₂玻片上的单量子点荧光亮态持续时间提高两个数量级, 掺杂于ITO中的单量子点的荧光寿命约减小为SiO₂玻片上的单量子点的荧光寿命的41%, 并且寿命分布宽度变小50%.     

近红外光区波长标准物质的研制

从薄膜材料选择出发,研究化学计量领域分光光度计近红外光区窄带干涉滤光片的加工工艺,并测试了此标准物质的均匀性及检定周期内的稳定性,同时评价了定值过程中的不确定度.结果表明所研制的近红外窄带干涉滤光片可作为分光光度计近红外光区的波长标准物质.     

室温单分子偶极取向与量子化再取向动力学实验研究

对室温下染料单分子进行了偶极取向和偶极再取向动力学的实验研究.利用共焦扫描显微镜光学系统与荧光偏振探测分析相结合的方法分别测量了聚合体薄膜中的单分子和无聚合体薄膜的单分子偶极方向变化特性,经采样统计测量镶嵌于聚合体薄膜中的单分子发生偶极再取向的概率约为5%—9%,无聚合体薄膜的单分子发生偶极再取向的概率约为26%.通过测量单分子荧光的偏振度轨迹曲线发现,偶极再取向存在着在多个偏振态之间的量子化跳跃行为. 关键词： 单分子 偶极取向 再取向 量子化跳跃     

基于实时优化单光子干涉可视度的相位编码量子密钥分发

在相位编码量子密钥分发系统中,单光子干涉可视度决定了系统的成码率。本文提出一种优化单光子干涉可视度的方法,即利用遗传算法和四通道偏振控制器实时补偿单光子偏振漂移,同时利用时分复用参考光连续无复位地补偿单光子相位漂移,最终在25km光纤中实时优化的单光子干涉可视度达到98.6%,相位编码量子密钥分发系统成码率为2.2kbit/s。     

Development of series SQUID array with on-chip filter for TES detector

A cold preamplifier based on superconducting quantum interference devices(SQUIDs)is currently the preferred readout technology for the low-noise transition edge sensor(TES).In this work,we have designed and fabricated a series SQUID array(SSA)amplifier for the TES detector readout circuit.In this SSA amplifier,each SQUID cell is composed of a first-order gradiometer formed using two equally large square washers,and an on-chip low pass filter(LPF)as a radiofrequency(RF)choke has been developed to reduce the Josephson oscillation interference between individual SQUID cells.In addition,a highly symmetric layout has been designed carefully to provide a fully consistent embedded electromagnetic environment and achieve coherent flux operation.The measured results show smooth V-Φcharacteristics and a swing voltage that increases linearly with increasing SQUID cell number N.A white flux noise level as low as 0.28μφ;/Hz;is achieved at 0.1 K,corresponding to a low current noise level of 7 pA/Hz;.We analyze the measured noise contribution at mK-scale temperatures and find that the dominant noise derives from a combination of the SSA intrinsic noise and the equivalent current noise of the room temperature electronics.     

Single-photon modulation spectrum

We present a robust method of single-photon modulation by directly modulating the single photons and observe its frequency spectrum. Compared with conventional photon counting technique, the single-photon modulation spectrum shows that the method could not only realize high-frequency modulation but also obtain higher signal-to-noise ratio. Moreover, the theoretical calculations show good agreement with the experimental results.     

低碳钢试件弹塑性边界的白光相关检测

金属试件的弹塑性边界检测对判断该试件是否失效有着重要意义,因此一直是研究人员较感兴趣的研究课题。利用激光和白光作为照明光源的方法都曾被提出以检测金属试件的弹塑性边界以及塑性变形。为避免激光测量的诸多缺点,本文提出一种用白光作为照明光源并结合数字图像处理来检测低碳钢试件弹塑性边界的方法。该方法将数字图像相关和低碳钢试件表面弹塑性变形前后对照明光强的反射特性结合起来以判断试件是否进入塑性屈服。文中通过对加载过程中低碳钢试件表面序列图像的处理,准确地判断了该试件是否进入塑性屈服,验证了该方法的可行性。     

Multichannel fetal magnetocardiography using SQUID bootstrap circuit

Fetal magnetocardiography （MCG） is a sophisticated non-invasive technique for the fetal heart diagnosis. We constructed a multichannel fetal MCG system based on a novel superconducting quantum interference device （SQUID） direct readout scheme called SQUID bootstrap circuit （SBC）. The system incorporates four SBC gradiometers for the signal detection and three SBC magnetometers as the references. The fetal MCG signal at a 28-weeks’ gestation was measured. By the fetal MCG signal separation and average, the P-wave and QRS complex can be clearly identified. These results indicate that the SBC is one of the most promising techniques for the fetal MCG recordings.     

螺吡喃分子光开关

螺吡喃是一类研究最早,最广泛的有机光致变色分子.利用光照前后螺吡喃分子结构上和光化学与光物理性质的变化,将其作为分子光开关材料被广泛应用于光电器件、化学传感、药物控制释放等领域.综述了部分螺吡喃分子光开关的合成和性质及其在相关领域中的应用,对其作为新型的荧光探针未来在生物成像领域的应用做了展望.