An effect of side chain length on the solution structure of poly(9,9-dialkylfluorene)s in toluene

The effect of side chain length of π-conjugated poly(9,9-dialkylfluorene)s has been studied in semi-dilute (10 mg/mL) toluene solutions using small-angle neutron scattering (SANS) and ¹H and ²H NMR spectroscopies. Under these conditions, SANS data indicate that poly(9,9-dinonylfluorene) and poly(9,9-dioctylfluorene) are dissolved down to the molecule level and appear as elongated one-dimensional chains (length >20-30 nm). In contrast, the shorter side chain polymers exhibit a self-association so that poly(9,9-diheptylfluorene) forms thin sheet-like (∼1 nm) and poly(9,9-dihexylfluorene) thin (∼1 nm) and thick sheet-like (>6 nm) aggregates. ¹H NMR data, together with the density functional theory (DFT) calculations, however, show that this occurs without changes in the conformation of the polymer backbone.     

Characterization of CuInS2 thin films for solar cells prepared by spray pyrolysis

We have made a study of the chemical composition, the electrical, the optical and the structural properties of polycrystalline CuInS₂ thin films prepared by spray pyrolysis to be used for thin film solar cells. These films were deposited starting from aqueous solutions with different chemical compositions ([Cu]/[In] and [S]/[Cu] ratios) and at different substrate temperatures. In all cases, the material is p-type with grains preferentially oriented in the (112) direction of the sphalerite structure. The electro-optical properties show a very strong dependence on the [Cu]/[In] ratio in the solution. Films with copper excess have smaller resistivity and better crystallinity than those which are stoichiometric or have indium excess. The results obtained in this work show the possibility of having CuInS₂ thin films with a wide range of resistivity, a fact that could be important for making solar cells based on this material.     

用工多样化与基层思想政治工作

随着国企体制改革的不断深入,江汉油田努力探索人力资源改革的新模式,用工形式呈现多样化趋势。如何在用工多样化的形势下加强和改进思想政治工作是当今基层思想政治工作的一项重要课题。通过强有力的思想政治工作,解决基层队伍中的新问题、化解新矛盾,为推动企业科学发展更好地发挥思想政治工作的保障作用。     

The Impact of Serial Solutions’ Summon™ on Information Literacy Instruction: Librarian Perceptions

Web-scale discovery systems, such as Serial Solutions’ Summon? Service, are replacing older federated search technologies as the tool for users to access library resources quickly and easily. The impact of Web-scale discovery systems on instruction is not known. This study of instruction librarian perceptions of Summon's impact on instruction and student information literacy skills is based on a survey. The survey reveals librarians’ ambivalence toward Summon. While some librarians agree that Summon has the potential to change the way librarians teach information literacy skills, it has not been fully integrated into the classroom.     

高校应用写作教学中的困惑与出路

应用写作以其广泛的社会需求而受到高校的关注,但在教学中存在着一些问题,主要有:不重视任课教师的选配、任课教师职称评定难、任课教师的理论教学与写作实践脱节、学生的言语能力与写作水平下降。为切实解决高校应用写作教学中存在的问题,为社会培养复合型应用人才,学校领导要充分重视,从政策上予以保证;同时,教师要从事一些秘书写作工作,将理论与实践结合起来。而重视教材建设等,是解决上述问题的重要措施。     

公路联网收费系统网络故障诊断与解决措施探讨

随着社会经济的蓬勃发展,我国的公路系统也越来越发达。网络给公路收费系统带来便利的同时,也带来了危机。本文对公路联网收费系统常见网络故障进行了分析,并提出了相关解决措施。     

常见网络故障及处理方法

计算机网络在现代企业中的应用及重要性与日俱增,这就要求我们的网络管理员在实际工作中,当网络发生问题后,在第一时间内以最快的速度和快捷的方法找出故障症结并迅速解决。本文就我们日常工作中遇到网络故障后如何分析进行探讨,并提出相应地解决方法。     

浅议ERP系统在企业财务管理中的应用

本文首先简单介绍了SAPERP系统;其次,分析了ERP系统对企业财务管理的影响;最后,探讨了ERP系统在企业财务管理中的应用问题及对策。     

浅谈网上银行存在的问题及解决办法

网上银行支持在网络上进行交易的虚拟银行。只要能够上网,无论身在何处,都能够安全便捷地管理自己的资产和享受银行提供的服务。然而网上银行存在诸多的安全问题。本文就针对这些安全问题提出相应的解决办法。