以三聚茚为核的星型电子受体材料的合成、 表征与光伏性能

以高度平面共轭的烷基取代三聚茚为中心核, 以噻吩基团桥联, 在末端连接氰基茚酮作为拉电子基团, 设计合成了一类星型受体分子2,2',2″-{[(5,5,10,10,15,15-己基-10,15-二氢-5H-二茚[1,2-a：1',2'-c]芴-2,7,12-三基)三(噻吩-5,2-二基)]三(亚甲基)}三(3-氧杂-2,3-二氢-1H-茚-2,1-二叉)三丙二腈(NFT-C6)和2,2',2″-{[(5,5,10,10,15,15-癸基-10,15-二氢-5H-二茚[1,2-a：1',2'-c]芴-2,7,12-三基)三(噻吩-5,2-二基)]三(亚甲基)}三(3-氧杂-2,3-二氢-1H-茚-2,1-二叉)三丙二腈(NFT-C10). NFT-C6和NFT-C10的最高占据轨道(HOMO)和最低未占轨道(LUMO)分别位于-5.66和-3.75 eV. 其薄膜在400~700 nm范围内具有较大的吸收强度, 最大吸收峰分别位于606和586 nm. 以聚[(2,6-{4,8-二[5-(2-乙基己基)噻吩-2-基]-苯并[1,2-b：4,5-b']二噻吩})-{5,5-(1',3'-二-2-噻吩基-5',7'-二(2-乙基己基)苯并[1',2'-c：4',5'-c']二噻吩-4,8-二酮)}](PBDB-T)为给体材料, 以NFT-C6或NFT-C10为受体材料制备了太阳能电池器件, 器件在300~700 nm之间具有较宽的响应光谱, 其光电转换效率(PCE)分别达到1.09%和5.23%. 原子力显微镜(AFM)结果表明, PBDB-T和NFT-C10共混制备的光伏器件活性层具有合适的相分离尺寸, 有利于激子的有效解离, 而PBDB-T: NFT-C6器件的活性层相分离尺寸过大, 增加了激子复合的几率, 使器件的短路电流、 填充因子和PCE降低. 研究结果表明, 基于三聚茚的星型光伏材料具有一定的应用前景.     

LBM-DEM四向耦合喷动床内介尺度模拟与分析

研究喷动床内颗粒的流动特性对于喷动床的设计和优化具有重要意义。基于气固两相流流动的LBM-DEM四向耦合模型,对单孔射流喷动床中颗粒的流动进行数值模拟。其中,气相采用修正的格子玻尔兹曼方法,颗粒相采用离散单元法,流固之间受力的双向耦合基于牛顿第三定律,颗粒与颗粒及颗粒与壁面的受力双向耦合采用软球模型。模拟得到了流化过程、颗粒与气体的速度分布、床层膨胀高度变化以及床宽对流化过程的影响。结果表明,喷动床内存在强烈的内循环,床宽增加导致颗粒运动能力减弱,射流速度增加使颗粒运动更加剧烈,床层膨胀高度增加。     

不同水胶比混凝土内部温湿度长期变化规律研究

鉴于混凝土内部温湿度显著影响混凝土耐久性, 为研究混凝土内部温湿度长期的变化规律, 将不同水胶比混凝土放置于室内大气环境中, 并测量其距离表面3cm、5cm、7cm及9cm处140d内温湿度的演变规律. 研究结果表明: 正常室温条件下, 混凝土内部温度变化主要受环境温度影响, 且与环境温度变化趋势基本相同, 浇筑完成7d后内部温度与环境温度温差大约为2℃, 60d以后内外温差基本消失. 高水灰比混凝土内部含水量充足, 140d内部相对湿度一直保持在85%以上; 低水灰比混凝土内部含水量较少, 早期相对湿度变化受水化耗水影响明显, 混凝土内部相对湿度存在明显梯度差, 5cm、7cm处相对湿度最低分别为60.18%和29.83%; 随着水化作用进行, 长期来看混凝土内部湿度逐步与环境湿度趋于一致.     

Translocation of Biopolymer Chain Through a Nanopore: Coil--Helix Transition

The translocation dynamics of a single biopolymer chain through a nanopore in a membrane is investigated by taking the coil-helix transition into account. Based on the changing of the free energy due to the coil-helix transition, the mean first passage time T is obtained, and then the corresponding numerical simulations are presented under different conditions. It is shown that the coil--helix transition can significantly shorten the translocation time of the biopolymer chain. In addition, we also discuss the scaling behaviour for T with the chain length N and some related problems.     

一种基于感兴趣区域提取的医学图像检索技术

针对胸部CT扫描图像库,提出了一种基于感兴趣区域提取的图像检索方法．首先为了提取感兴趣区域,提出一种基于灰度层共现矩阵的区域增长算法,分割出病灶区域,再通过闽值算法进行边界的磨合,然后针对感兴趣区域提取形状和分布特性作为图像匹配准则的客观依据．最后,将该算法与其他底层特征算法进行比较和分析．实验结果表明,该算法能够比较有效地应用于基于内容的医学图像检索系统中．     

微视频在无机化学实验教学中的应用

To improve the students' autonomous learning ability and learning enthusiasm in practice course,we introduce micro video,which is short,fast,precise,easy,and fun,into inorganic chemistry laboratory teaching.As an important supplementary means of teaching,micro videos will solve the repeated problems,help students promote study efficiency,provide students with a good way for communication,and improve the students' study enthusiasm.     

Chaos in an Ar+ Composite Resonator Laser Using KNSBN;Cu Crystal Self-Pumped Phase-Conjugator

Observation of the dynamics in a single-mode Ar⁺ composite resonator laser using KNSBN;Cu crystal self-pumped phase-conjugator is reported. The sequence of instabilities occurring on gain change corresponds to the transition the chaos of the logistic equation. Period-doubling route to chaos, and period-5, -3,-3×2, and -2 together with -3 windows in the chaotic range were observed. The strange attractor which is similar to that of the forced Duffing equation is obtained by reconstructing phase-space pictures of the system.     

横向磁场导致CO2激光器混沌运转及其奇异吸引子的观测

在外加磁场的情况下,对单模均匀展宽CO₂激光器进行了实验研究。改变磁场的大小,观察到了自脉动和混沌现象,同时还获得了该系统的奇异吸引子,并对其物理机制进行了探讨。     

SYNTHESIS AND NMR CHARACTERIZATION OF PRECURSORS OF EPOXY NETWORK AS POLYMER HOST FOR SOLID ELECTROLYTE

To raise the room temperature ionic conductivity and improve the mechanical strength of a PEO-based polymer electrolyte, a noncrystalline two-component epoxy electrolyte system has been prepared. The diglycidyl ether of polyethylene glycols as precursors of the system were synthesized by a two-step process. The presumed structure of the product was characterized, by ~(13)C, ~1H NMR and IR spectroscopy. It was found that a side-reaction occurred between the secondary hydroxyl group of PEG-chlorohydrin and epichlorohydrin in some degree, resulting in a by- product containing—CH_2Cl side group. By selecting a characteristic signal, which is undistorted by the increase in the length of CH_2 CH_2—O segment, a ~1H NMR approach of determining the equivalent epoxy weight (EEW) was proposed. The method is valid to specimens even though the EEW is as high as 2,000. The examination of the specimens by DSC showed that epoxidation greatly depressed the crystallinity of the PEG's, whereas the T_g was raised.     

VISCOELASTICITY AND IONIC CONDUCTIVITY OF TWO-COMPONENT EPOXY NETWORK CONTAINING LITHIUM PERCHLORATE*

Polymeric solid electrolyte system composed of triglycidyl ether of glycerol (TGEG), diglycidyl ether of polyethylene glycol (DGEPEG)and LiClO_4 salt were synthesized. In this" system the electrolyte has a pecularity that not merely can the LiClO_4 provide ionic carriers, but also catalyze the crosslinking reaction without adding an usual curing agent. The effect of salt content and degree of crosslinking on the viscoelasticity and ionic conductivity were studied. Both WLF and VTF equations were used to treat the experimental data in order to elucidate the mechanism of ionic conduction. It was found that the ionic conductivity of the system is carded out through the segmental motion mechanism. However, the data must be treated with care. For example, in evaluating WLF parameters, the contribution concerned with ionic carrier generation with temperature to the conductivity must be differentiated from that concerned with segmental motion. Besides, the temperature range suitable to WLF equation must also be considered. For VTF equation, it might be inapplicable ff the temperature is too low and close to the glass transition temperature of the specimen. Further study is needed in order to have a quantitative information on the limitation of these equations.