Ladder‐Type Nonacyclic Arene Bis(thieno[3,2‐b]thieno)cyclopentafluorene as a Promising Building Block for Non‐Fullerene Acceptors

The ladder‐type nonacyclic arene (bis(thieno[3,2‐b]thieno)cyclopentafluorene (BTTF)) has been designed and synthesized through fusing thienothiophenes with the fluorene core from the synthon of dimethyl 9,9‐dioctyl‐2,7‐bis(thieno[3,2‐b]thiophen‐2‐yl)fluorene‐3,6‐dicarboxylate. With BTTF as the central donor unit, a novel acceptor–donor–acceptor (A‐D‐A) type non‐fullerene small‐molecule acceptor ( BTTFIC ) was prepared with 1,1‐dicyanomethylene‐3‐indanones (IC) as the peripheral acceptor units. The energy level of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of BTTFIC locate at ?5.56 and ?3.95 eV, respectively, presenting a low optical band gap of 1.58 eV. Encouragingly, polymer solar cells based on the blends of BTTFIC with both the representative wide‐ and low‐bandgap polymer donors (PBDB‐T, 1.82 eV. PTB7‐Th, 1.58 eV) offer power conversion efficiencies over 8 % (8.78±0.18 % for PBDB‐T: BTTFIC and 8.18±0.29 % for PTB7‐Th: BTTFIC ). These results highlight the advantage of ladder‐type BTTF on the preparation of nonfullerene acceptors with extended conjugated backbones.     

Quantum Binary Search Algorithm

International Journal of Theoretical Physics - Problems which can be solved on classical computer in polynomial time may not be able to be solved on quantum computer. And a quantum algorithm will...     

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本文利用广义p值和广义置信区间理论,研究了两独立服从双参数指数分布产品平均寿命比率的统计推断问题.给出了平均寿命比率的广义置信区间,并对该区间的覆盖率和区间长度进行了数据模拟,模拟结果与已有文献中的近似置信区间进行了比较,结果显示本文给出的广义置信区间的区间覆盖率和区间长度都要优于近似置信区间,特别是在小样本的情况下.     

Ce(Ⅳ)/Ce(Ⅲ)电对在甲基磺酸体系中还原动力学的研究

采用循环伏安、极化曲线、交流阻抗等方法对甲基磺酸体系中Ce(Ⅳ)/Ce(Ⅲ)电对在Pt电极上的反应机制和Ce(Ⅳ)还原反应的动力学进行了研究。极化曲线分析表明,Ce(Ⅳ)还原反应是单电子过程,在低过电位下电荷传递电阻为129.1Ω.cm2。循环伏安结果显示:Ce(Ⅳ)/Ce(Ⅲ)电对在Pt电极上的反应是准可逆过程,计算得到Ce(Ⅳ)的扩散系数Dc为5.89×10-6cm2.s-1,标准速率常数k0=3.06×10-4cm.s-1。交流阻抗图谱表明,Ce(Ⅳ)在电解液中的扩散是制约电极反应速率的重要因素。     

基于极化强度叠加模型的高功率微波混合气体传播特性

 基于气体极化强度叠加模型,推导了混合气体的介电常数,得到了高功率微波在混合气体中传播时的折射指数和衰减系数。研究发现,高功率微波大气电离产生的混合气体是快速时变的色散有耗介质。根据其色散性分析了微波在混合气体中的传播速度以及微波脉冲在其中的展宽效应,同时,根据其有耗性对微波脉冲在混合气体中传播时的缩短效应进行了研究。研究结果均能自洽地过渡到对流层或电离层电波传播理论。     

具有消像差和光程补偿功能的新型取样光栅

 在惯性约束聚变(ICF)终端光学聚焦系统中,采用取样光栅将透射的高功率三倍频光按约0.5%的效率进行聚焦采样,送入能量计中进行诊断。提出了用取样光栅对结构取代单取样光栅,通过合理选择系统参数,包括两块光栅的距离、光栅倾斜角度等,设计出的消像差取样光栅可同时进行能量诊断、光脉冲响应测量、以及远场光斑质量的检测。计算结果显示：光程差从8.3 cm降低到8.7 mm,像点的均方根半径为0.777 μm,达到衍射极限和使用要求。这为ICF系统中激光能量、波前畸变的诊断提供了一种可供选择的新诊断装置。     

Trajectory Segmentation and Symbolic Representation of Dynamics of Delayed Recurrent Inhibitory Neural Loops

We develop a general symbolic dynamics framework to examine the dynamics of an analogue of the integrate-and-fire neuron model of recurrent inhibitory loops with delayed feedback, which incorporates the firing procedure and absolute refractoriness. We first show that the interaction of the delay, the inhibitory feedback and the absolute refractoriness can generate three basic types of oscillations, and these oscillations can be pinned together to form interesting coexisting periodic patterns in the case of short feedback duration. We then develop a natural symbolic dynamics formulation for the segmentation of a typical trajectory in terms of the basic oscillatory patterns, and use this to derive general principles that determine whether a periodic pattern can and should occur.     

Hydrothermal synthesis and magnetic properties of gadolinium-doped CoFe2O4 nanoparticles

CoFe_2−xGd_xO₄ (x=0-0.25) nanoparticles were synthesized via a simple hydrothermal process at 200 °C for 16 h without the assistance of surfactant. The as-synthesized powders were characterized by X-ray diffraction, transmission electron microscopy, and a vibrating sample magnetometer. The X-ray diffraction results showed that the as-synthesized powders were in the pure phase with a doping amount of ≤0.25, and the peaks could be readily indexed to the cubic spinel cobalt ferrite. Transmission electron microscopy and high resolution transmission electron microscopy observations revealed that the gadolinium-doped cobalt ferrite nanoparticles were single crystal, roughly spherical, uniformly distributed, and not highly agglomerated. The room temperature magnetic field versus magnetization measurements confirmed a strong influence of gadolinium doping on the saturation magnetization and coercivity due to large lattice distortion and grain growth of small particles.     

拼接光栅缝隙对激光脉冲光强分布的影响

以拼接光栅作为色散元件的激光脉冲压缩器中,要求脉冲压缩光栅表面光强分布均匀、能量输出效率高。利用菲涅耳-基尔霍夫衍射原理对脉冲压缩光栅表面光强和远场光强分布进行了研究。计算了拼接光栅缝隙宽度对光栅表面光强变化量和远场光强极大值的影响。在利特罗角附近入射时发现激光脉冲光强分布与拼接光栅缝隙宽度相关,得出了光栅拼接缝隙宽度应控制在0.5 mm以内。适当提高缝隙衍射效率能够改善光强分布均匀性和提高光能量输出,提出了对拼接缝隙采用两次重复曝光以提高其衍射效率的方法。     

反相高效液相色谱法同时测定果汁中8种添加剂

建立了反相高效液相色谱法（ＲＰ－ＨＰＬＣ）同时直接测定进口果汁中柠檬黄和苋菜红等８种添加剂含量的方法。色谱柱为Ｈｙｐｅｒｓｉｌ　ＢＤＳ　Ｃ１８柱（２５０ｍｍ×４．０ｍｍｉ．ｄ,５μｍ）,流动相为甲醇／０．０１ｍｏｌ／Ｌ乙酸铵,梯度洗脱,流速为 １．０ ｍＬ／ｍｉｎ,柱温为 ４０℃,ＤＡＤ紫外检测器波长为 ２３０ ｎｍ。在此色谱条件下,各组分在１０ ｍｉｎ内均得到良好分离。平均回收率为 ９０％～１１４％,相对标准偏差 １．３％～８．０％。