基于主客体识别技术构建的DNA电化学传感识别灯塔

传统的电化学DNA生物传感技术通常包括以下3个步骤,即电极表面探针DNA的固定、固液两相间DNA的杂交反应和电化学信号的读出,由于探针和目标序列的杂交过程发生在两相间,所以降低了杂交效率.在此,我们基于主客体识别和分子信标技术,设计了一种新型的电化学DNA传感器,可实现DNA在均一水相中的杂交反应,然后杂交体被捕获到电极表面进行电化学检测,具有高的灵敏度和选择性.     

聚苯胺纳米线修饰的DNA电化学传感器的研究

采用电流密度递减的方法在玻碳电极表面修饰聚苯胺纳米线(PAINW), 以SEM对其形貌进行表征, 测得PAINW的尖端直径在80～100 nm之间. 以乙基-(3-二甲基丙基)碳化二亚胺盐酸盐(EDC)为偶联活化剂, 将5'-磷酸基修饰的寡聚核苷酸片断共价固定在聚苯胺修饰的电极上, 一定条件下, 以亚甲基蓝为电化学杂交指示剂, 采用差分脉冲伏安法对杂交信号进行检测, 实现了对特定序列DNA片段的互补、非互补序列的识别.     

共轭二茂铁基席夫碱的合成及电化学性质

以乙炔二茂铁为原料,通过Sonogashira和胺醛缩合反应合成了三个共轭二茂铁基席夫碱配合物,通过元素分析、1H和13C NMR对产物进行了表征,并用X射线单晶衍射测定了配合物I的晶体结构,电化学研究表明合成的配合物均经历一个可逆的单电子氧化还原过程。     

Preliminary study of the higher-harmoni ccavity for HLS-Ⅱ

A higher-harmonic cavity will be used to increase the beam lifetime and suppress coupled-bunch instabilities for Hefei Light Source-Ⅱ. In this paper, results simulated by the particle-tracking model confirm that tuning in the harmonic cavity may suppress the parasitic coupled-bunch instabilities. The factors calculated for lifetime improvement are larger than 2.5. The 3rd and 4th harmonic cavities have been designed. In particular, the absorbers and antenna couplers are applied in harmonic cavities to damp the higher order modes. Finally, the 4th harmonic cavity similar to the Duke's RF cavity will be used for HLS-Ⅱ.     

基于主客体识别作用构建的电化学发光传感器检测丹参中汞离子

使用联吡啶钌(Ru(bpy)32+)/β-环糊精-金纳米粒子(β-CD-AuNPs)/全氟磺酸(Nafion)复合物和二茂铁标记(Fc)的DNA探针(Fc-DNA)构建了电化学发光(Electrochemiluminescence,ECL)生物传感器,将其用于检测中药材丹参中的汞离子。 该传感器包含ECL发光基底和ECL强度开关两部分,将Ru(bpy)32+/β-CD-AuNPs/Nafion组装到玻碳电极(GCE)上构成发光基底,产生稳定的ECL信号;Fc-DNA探针作为ECL信号开关,通过分子识别策略设计,利用β-CD与Fc的主客体相互作用与β-CD-AuNPs相连。 该检测方法和以往的汞离子检测方法相比,具有背景信号低、选择性高、仪器简单、操作快速等特点。 该 “Off-On” 电致化学发光生物传感器在0.04~800 ng/mL范围内对Hg²⁺具有良好的线性响应,检测限为0.02 ng/mL(S/N=3)。     

Calculations for shortening the bunch length in storage rings using a harmonic cavity

Using the Hefei Light Source phaseⅡproject(HLS-Ⅱ)as an example,a theoretical analysis of shortening the bunch lengths using a higher harmonic cavity(HHC)is given.The threshold voltage of an active HHC and the threshold tuning angle of a passive HHC are first analysed.The optimum tuning angle for the constant detuning scenario and the optimum harmonic voltage for the constant voltage scenario are presented.The calculated results show that the reduced bunch length is about half that of the nominal bunch.The bunch lengths vary from 11 mm at 0.1 A to 7 mm at 0.4 A for the constant detuning scenario,while the bunch lengths are around 7 mm over the beam current range for the constant voltage scenario.In addition,the synchrotron frequency spread is increased.It indicates that HHC may be used to reduce the bunch length and increase the Landau damping of synchrotron oscillations in a storage ring.     

Calculations for shortening the bunch length in storage rings using a harmonic cavity

Using the Hefei Light Source phase Ⅱ project （HLS- Ⅱ） as an example, a theoretical analysis of shortening the bunch lengths using a higher harmonic cavity （HHC） is given. The threshold voltage of an active HHC and the threshold tuning angle of a passive HHC are first analysed. The optimum tuning angle for the constant detuning scenario and the optimum harmonic voltage for the constant voltage scenario are presented. The calculated results show that the reduced bunch length is about half that of the nominal bunch. The bunch lengths vary from 11 mm at 0.1 A to 7 mm at 0.4 A for the constant detuning scenario, while the bunch lengths are around 7 mm over the beam current range for the constant voltage scenario. In addition, the synchrotron frequency spread is increased. It indicates that HHC may be used to reduce the bunch length and increase the Landau damping of synchrotron oscillations in a storage ring.