Intermolecular H···O═C bonds induced 2D self‐assembly of thiophene based diketopyrrolopyrrole derivative

Compounds with diketopyrrolopyrrole (DPP) and thiophene moieties have attracted considerable attention because of their promising charge transport properties. The molecular conformation and self‐assembly of 2,5‐dihexadecyl‐3,6‐di(thiophen‐2‐yl)‐2,5‐dihydropyrrolo[3,4‐c]pyrrole‐1,4‐dione (TDPP‐C16) molecule have been investigated by scanning tunneling microscopy and density functional theory alculation. The TDPP‐C16 molecules adsorb with their optimized S‐shaped conformation and form a zipper‐like pattern on highly oriented pyrolytic graphite surface. R and S rotated structures are observed. The nanostructure is dominated by intermolecular double hydrogen bonds between C═O of the DPP units and hydrogen atom of thiophene rings in the neighboring molecules in each row. Atomic force microscopy and density functional theory calculation also display the existence of strong intermolecular hydrogen bonding. The results provide molecular evidence for the intermolecular interactions of the surface structure, which could benefit to the design of the organic semiconducting materials and understanding of underlying principle of charge transfer process. Copyright © 2017 John Wiley & Sons, Ltd.     

Equilibrium phase behavior of aqueous two-phase systems containing 17R4/L64 and citrates

The cloud points (CPs) of the copolymers 17R4 and L64 were first measured, and then the effects of salts ((NH₄)₃C₆H₅O₇, K₃C₆H₅O₇) on 17R4 and L64 were researched. After finishing the work described above, the temperature (278.15, 283.15, and 288.15) K of aqueous two-phase systems was determined, which consist of 17R4-(NH₄)₃C₆H₅O₇, 17R4-K₃C₆H₅O₇, L64-(NH₄)₃C₆H₅O₇, and L64-K₃C₆H₅O₇. Finally, the liquid–liquid equilibrium (LLE) data of binodal curve and the tie line for 17R4-(NH₄)₃C₆H₅O₇ aqueous two- phase systems (ATPSs) 17R4-K₃C₆H₅O₇ ATPSs, L64-(NH₄)₃C₆H₅O₇ ATPSs, and L64-K₃C₆H₅O₇ ATPSs were obtained. Nonlinear fitting of the empirical equation was used for making the diagram. The results showed that the change in the size of the two-phase areas increases with the increase of temperature. The capacity of the salts to induce phase segregation follows the Hofmeister series, that is, K₃C₆H₅O₇?>?(NH₄)₃C₆H₅O₇. In addition, the findings also showed that the phase separation ability of 17R4 is better than that of L64.     

Two-dimensional self-assembly of esters with different configurations at the liquid-solid interface

Self-assembled monolayers of hexadecyl palmitate (HP) and 3,3′-thiodipropionic acid di-n-octadecyl ester (TADE) physisorbed on highly oriented pyrolytic graphite (HOPG) are investigated using scanning tunneling microscope (STM) and computer simulation. Both molecules form alkane-like linear shapes to maximize the interactions with substrate when they adsorb on HOPG surface. The HP molecules self-assemble into lamellae with the chain-trough angle of 48°, which is the result of a shifting 3/2 units from the adjacent molecule in a lamella. Based on the simulation insights combined with STM images, we confirm that a perpendicular orientation appears in which the HP molecular backbone is rotated 90° with respect to the substrate such that the carbonyl points away from the HOPG surface. TADE molecules form three kinds of configurations with chain-trough angles of 90°, 72° and 60° by shifting 0, 1/2 and 1 units from their adjacent molecules, respectively. The bright stripes in STM images reveal the electron density distribution of the part between two ester groups. The energy differences of three TADE adsorption configurations by molecular mechanics (MM) simulation are used to explain the structural coexistence phenomenon. It is also shown that lattice match between alkyl chain of molecules and HOPG substrate could change molecular conformation upon self-assembly.     

基于微分变分不等式的多商品流网络动态模型

针对由多个制造商和多个零售商构成并且具有多商品流的供应链网络,建立了制造商、零售商之间从事微分Nash博弈的供应链网络动态模型.首先,在介绍微分变分不等式定义的基础上,利用微分变分不等式的方法建立了制造商、零售商以及供应链网络的均衡条件.然后,在正则条件下分析了供应链网络动态模型解的存在性条件.最后,利用数值算例验证了模型的合理性.     

New sets of frequency-hopping sequences with optimal Hamming correlation

Frequency-hopping spread spectrum and direct-sequence spread spectrum are two main spread coding technologies in communication systems. Frequency-hopping sequences are needed in FH-CDMA systems. In this paper, a construction of optimal sets of frequency-hopping sequences using cyclotomy and the Chinese remainder theorem is introduced. It generalizes some earlier constructions, and produces new optimal sets of frequency-hopping sequences.     

长吻鮠肝脏线粒体DNA的研究

采用密度梯度离心法及ＤＮａｓｅⅠ、ＲＮａｓｅ消化法制备并纯化了长吻鮠　（ＬｅｉｏｃａｓｓｉｓＬｏｎｇｉｒｏｓｔｒｉｓ）肝脏线粒体ＤＮＡ（ｍｔＤＮＡ）．用９种限制性内切酶对ｍｔＤＮＡ进行了分析．ＸｈｏⅠ、ＢｇｌⅡ、ＥｃｏＲⅠ、ＰｓｔⅠ、ＢｇｌⅠ、ＢａｍＨⅠ、ＸｂａⅠ、ＨｉｎｄⅢ、ＳａｌⅠ在长吻　ｍｔＤＮＡ分子上分别具１、３、３、２、１、２、４、７、０个切点．ｍｔＤＮＡ分子量约１０．３１×１０５道尔顿，大小为１６．６９ｋｂ．根据单酶和双酶解片段的数目和分子量，建立了长吻　ｍｔＤＮＡ的限制性酶切图谱．     

弯道水流二维浅水模型的修正研究

借鉴有关弯道水流流速分布的研究成果,计入深度平均流速与真实流流速分布差值引起的扩散效应,在正交曲线坐标系下建立了平面二维浅水模型.采用以标准κ-ε模型为基础的曲率效应修正紊流模型模拟紊动应力项,在一定程度上考虑了流线弯曲水流紊动应力的各向异性.应用控制体积法和交错网格法离散方程,并用SIMPLEC算法求解离散方程;同时采用修正后的模型对90°弯道水流进行了数值模拟,并与原模型的计算结果及实测资料进行了比较,结果表明该模型能够有效地模拟流线弯曲水流的水力特性.     

一种同轴低电感低抖动多级多通道气体开关

 研制了一种触发电极位于放电通道之外、间隙电极为环状不锈钢弹簧的同轴多级多通道气体开关。该开关通过分布电容耦合实现触发，利用多间隙串联减小抖动，利用弹簧不同匝之间电感隔离形成多通道放电。实验表明：该开关触发可靠、电感低（～20nH）、抖动小（～3ns）、触发特性稳定。     

湖北绿茶中两种新的没食子酸类衍生物的结构鉴定

用2D NMR技术研究了从绿茶中分离得到的2种新的没食子酸类衍生物,对其¹H和¹³C NMR谱线作了全归属.