Effect of Background Noise on the Photon Statistics of Triggered Single Molecules

We theoretically derive exact expressions for Mandel‘s Q parameter of the triggered single molecular source, which is inferred from the probabilities PRs (n) using the recorded of each photon detection event based on Hanbury Brown and Twiss detection. The real triggered source is recognized as an ideal single photon source with a Poissonian statistics background. How to decease the background and to increase the efficiency are discussed. It is established that the sub-Poissonian statistics formation can be determined by comparing the measured QRs of the real single triggered molecular with Qc of the Poissonian source containing the same mean photons. By this method, we also give an efficient way to measure signal-to-background ratios of triggered single photons.     

硫化ZIF-67薄膜作为方酸敏化太阳能电池对电极的研究

沸石-咪唑框架结构(ZIFs)是一种新型多孔材料,具有表面积大、孔隙度高、孔隙大小可调节和通道规则等独特的优点。本文通过硫化涂覆在导电玻璃上的ZIF-67薄膜,制备了多孔碳和硫化钴复合材料,研究了其对I-/I-3氧化还原对的催化性能,以替代铂作为方酸染料敏化太阳能电池的对电极。通过X射线衍射、扫描电镜和等温吸附的测量,分析了硫化ZIF-67得到的对电极多孔膜的结构和形态特征,并通过Tafel曲线和电化学阻抗谱图对其催化性能进行评价。结果表明,硫化60min的ZIF-67对电极催化性能与Pt对电极相当,方酸敏化太阳能电池的光电转换效率分别是4.03%和4.10%。     

大豆异黄酮和大豆皂甙的分离纯化研究

黄酮类化合物的分离精制常用溶剂沉淀、pH梯度萃取法和柱色谱法.其中,溶剂萃取法虽然成本较低,但工艺过程繁琐,得率低且产品纯度不高.PH梯度萃取法所获得高纯度的黄酮化合物单体,可满足结构鉴定.柱色谱法是精制黄酮类化合物最常用的方法之一,Naim等曾用氧化铝柱从大豆提取物中成功分离了在C5位有羟基和在C5位没有羟基的两大类异黄酮组分,利用聚酰胺柱进一步从不含C5位羟基的异黄酮组分中分离出两种异黄酮单体.     

Nafion修饰电极同位镀金膜阳极溶出伏安法测定痕量砷

金膜电极阳极溶出伏安法测定痕量砷已有报道,但铜、锑、铋存在严重干扰。本文采用Nafion修饰电极同位镀金膜阳极溶出伏安法测定痕量砷,大大提高了其选择性,铜、锑、铋分别为砷含量的6倍,3倍和6.5倍以下时,不干扰测定;测定灵敏度也较同位镀金膜电极时高。本法应用于标钢和黄河底泥中砷含量的测定,均获得满意结果。     

0.1——1毫升适用范围之滴定装置

本文介绍的滴定装置,具有容积大于1毫升的主件,和一支容积与它相当的平衡管。溶液的排放,系由滴定管尖的表面张力与被平衡管降低了的溶液静压力控制。这种装置可由简单的玻璃器材装配成。构造和操作装置中有一个三向活塞,被固定在支架上:它的三支支管分别借橡皮管连接2毫升注射器,分度玻管与平衡管。连接平衡管的橡皮管较长, 可绕平衡管摆动。分度玻管可以是1毫升Bang滴定管的标度部分,其最小分度为0.01毫升,估计读数至小数第三位;下端连接毛细管尖。平衡管是由一支细玻管插入带支管的粗玻管构成的;细玻管的内径几乎与分度玻管内径相等,长度相当于分度玻管零刻线至毛细管尖收缩处。     

Fabry–Prot resonance coupling associated exceptional points in a composite grating structure

The exceptional point(EP) is a significant and attractive phenomenon in an open quantum system. The scattering properties of light are similar to those in the open quantum system, which makes it possible to achieve EP in the optic system. Here we investigate the EP in a Fabry–P′erot(F–P) resonant coupling structure. The coupling between different types of F–P resonances leads to a near zero reflection, which results in a degeneration of eigenstates and thus the appearing of EP. Furthermore, the multi-wavelength EPs and unidirectional invisibility can be achieved which may be used in integrated photonics systems.     

一个基于差积的匿名会议密钥分配方案

本文基于椭圆曲线上向量差积的性质,提出了一个基于差积的会议密钥分配方案.在此方案中,会议主席利用三个多项式来隐藏真正的会议密钥,使得该方案具有较强安全性和匿名性.     

α—溴代芳基酮还原脱溴的新方法

α—溴代芳基酮的还原脱溴是有机化学中一种非常重要的官能团相互转换，通常有机合成中经常采用的是由芳基酮来制备α—溴代芳基酮，而反过来由α—溴代芳基酮来制备芳基酮的研究甚少，现在对碲使α—溴代芳基酮的还原脱溴反应进行研究，不仅拓宽了碲的应用范围，而且对将...