Material issues for construction of organic and polymeric driving circuits for display and electronic applications

Organic and polymeric driving circuits may be a possible alternative to realize low cost flexible and large area flat panel displays. Recent efforts have been directed to the discovery of solution processable polymeric semiconductors for the ease of fabrication and low cost. In this paper, we report the investigation of various 3‐substituted regioregular polythiophenes as active semiconductors for field‐effect transistors. The best transistor performance has been found with regioregular poly(3‐heaxylthiophene). The difference in their device performance was correlated to the structure and morphological behavior of these regioregular polythiophenes.     

Silsesquioxane Resins as High‐Performance Solution Processible Dielectric Materials for Organic Transistor Applications

Silsesquioxane polymers have been successfully used as the dielectric layer in organic field‐effect transistors (FETs) deposited on robust, plastic substrates. Performance comparable to that found with silicon substrates having SiO₂ as the active dielectric layer was observed with six p‐ and n‐ channel organic semiconductors. These organopolysiloxane materials can be deposited using conventional liquid coating technologies and are compatible with non‐photolithographic microcontact printing. Their low curing temperature permits the use of a variety of low‐cost plastic materials as substrates in FET devices. These findings have facilitated the realization of low‐cost, large area plastic electronics.     

Bis­(tetra­phenyl­phospho­nium) (μ‐tetra­thio­tungstenio‐κ4S,S′:S′′:S′′′)­bis­[(cyano‐κC)­cuprate](2–) aceto­nitrile solvate monohydrate

The reaction of CuCN and KCN with (NH₄)₂[WS₄] followed by cation exchange with PPh₄Br produced the title compound, (C₂₄H₂₀P)₂[Cu₂WS₄(CN)₂]·CH₃CN·H₂O or (PPh₄)₂[(NC)Cu(μ‐S)₂W(μ‐S)₂Cu(CN)]·MeCN·H₂O. In the structure of the dianion, [(NC)Cu(μ‐S)₂W(μ‐S)₂Cu(CN)]²⁻, the WS₄ moiety acts as a bidentate ligand that binds two CuCN groups, thus forming a slightly bent WCu₂ core with approximate D_2d symmetry. The W—Cu distances are in the range 2.6463 (6)–2.6545 (6) Å.     

摩托车正时链和传动链磨损特性的研究

研究油润滑条件下摩托车发动机正时链的磨损特性,发现疲劳磨损,裂纹的形成和扩展是影响疲劳寿命的主要因素;定期刷油或滴油润滑条件下,摩托车传动链的磨损机制是磨粒磨损,并伴有疲劳磨损,销轴和套筒零件的渗层及心部组织等是影响链条磨损特性的重要因素,因为中碳调质钢经碳氮共渗后可获得弥散分布的颗粒状碳化物的表层组织及回火屈氏体的心部组织,从而显示出表层耐磨、心部强韧性好及抗塑变能力高的综合机械性能。     

Dynamic Time-Dependent Emission in Solution and Stable Dual Emission in Solid Matrix Exhibited by a Single-Component Fluorescence System

Organic luminescent materials with time-dependent emission colors show promising applications in the fields of chemical sensing, high-resolution bioimaging, and high-security information encryption. Herein a time-dependent fluorescence system based on a spirocyclic scaffold-bridged cyanostilbene dimer ( SDCS ) as the single component in a mixed CH₃CN/H₂O solvent is presented. Specifically, the original orange-emitting nanoparticles prepared from SDCS by reprecipitation can transform into green-emitting nanosheets over time driven by supramolecular self-assembly. It is worth noting that such a transformation rate can be controlled by tuning the water fraction. Based on these unique properties, fluorescent binary codes are developed, enabling time-dependent information encryption with a higher level of security. Moreover, the dual color can be individually fixed by solid matrices such as hydrogel or powder. The obtained luminescent powders are successfully used in two-color fluorescence imaging of latent fingerprints. This work demonstrates the use of a supramolecular strategy to control multiple emissions in a single-component system for multifunctional applications.     

Security of continuous-variable measurement-device-independent quantum key distribution with imperfect state preparation

The state preparation operation of continuous-variable measurement-device-independent quantum key distribution (CV-MDI-QKD) protocol may become imperfect in practical applications. We address the security of the CV-MDI-QKD protocol based on imperfect preparation of the coherent state under realistic conditions of lossy and noisy quantum channel. Specifically, we assume that the imperfection of Alice's and Bob's practical state preparations equal to the amplification of ideal modulators and lasers at both Alice's and Bob's sides by untrusted third-parties Fred and Gray employing phase-insensitive amplifiers (PIAs), respectively. The equivalent excess noise introduced by the imperfect state preparation is comprehensively and quantitatively calculated by adopting the gains of PIAs. Security analysis shows that CV-MDI-QKD is quite sensitive to the imperfection of practical state preparation, which inevitably deteriorates the performance and security of CV-MDI-QKD system. Moreover, a lower bound of the secret key rate is derived under arbitrary collective attacks, and the upper threshold of this imperfection tolerated by the system is obtained in the form of the specific gains of PIAs. In addition, the methods presented will improve and perfect the practical security of CV-MDI-QKD protocol.     

二维纳米片组成的花状铁醇盐及其微纳结构三氧化二铁衍生物的储锂性能

Fe₂O₃作为锂电池负极材料具有诸多优点,但其较低的本征电导率和充放电循环过程中材料粉化使得其电化学储锂性能有待改善。 本文以具有花状微纳结构的铁醇盐为反应中间体,在空气气氛下烧结制备出具有花状微纳结构的铁基负极材料Fe₂O₃。 纳米花状的铁醇盐可以在低烧结温度下转化为目标产物,从而使得产物能够保持中间体的形貌。 300 ℃热处理条件下,所得样品在电流密度为200 mA/g时首次放电比容量为1360 mA·h/g,循环100次后的容量仍然达到515.6 mA·h/g;相比之下,450和800 ℃热处理所得样品100次循环后,比容量分别为247.6和206.7 mA·h/g。 微纳结构在增加材料的活性的同时,也能够抑制材料的粉化现象,因而所制得的材料表现出较大的比容量和良好的循环性能,为解决Fe₂O₃负极材料循环性能差的问题提供了思路。     

Experimental investigations of mechanical and reaction responses for drop-weight impacted energetic particles

Low-velocity drop-weight impact experiments on individual and multiple Cyclotetramethylene tetranitramine (HMX) energetic particles were performed using a modified drop-weight machine equipped with high-speed photogra-phy components. Multiple particles experienced more severe burning reactions than an individual particle. Comparisons between impacted salt and HMX particle show that jetting in HMX is mainly due to the motion of fragmented parti-cles driven by gaseous reaction products. Velocity of jetting, flame propagation, and area expansion were measured via image processing, making it possible to quantify the chemi-cal reaction or mechanical deformation violence at different stages.