关于有机物分子式计算的多种解法

近年来,关于有机物分子式的计算已成为高考命题的热点之一.通常情况下,这类问题对大部分考生来说有一定难度;有些考生虽然最终能得到正确的答案,但却耗费了大量宝贵时间,影响了考试成绩.因此,如何既快又准地得到答案,是一个急需解决的问题.     

基于WWW的文本信息挖掘

基于 Ｉｎｔｅｒｎｅｔ 的信息挖掘是数据挖掘和数据仓库技术中的重要组成部分,也是网络信息处理领域中的一项新课题。本文介绍了网络信息挖掘的概念,并给出了在 Ｗｏｒｌｄ Ｗｉｄｅ Ｗｅｂ 上针对文本信息进行信息挖掘的算法和步骤。     

"图书馆之城"下的深圳地区医院图书馆发展思路

介绍深圳“图书馆之城”建设的背景和成果,分析深圳地区各医院图书馆的现状,提出借鉴“图书馆之城”的建设思路,从规划、创新、特色等方面建设深圳地区医院图书馆。     

Hierarchical structural complexity in atomically precise nanocluster frameworks

The supramolecular chemistry of nanoclusters is a flourishing area of nano-research; however, the controllable assembly of cluster nano-building blocks in different arrays remains challenging. In this work, we report the hierarchical structural complexity of atomically precise nanoclusters in micrometric linear chains (1D array), grid networks (2D array) and superstructures (3D array). In the crystal lattice, the Ag₂₉(SSR)₁₂(PPh₃)₄ nanoclusters can be viewed as unassembled cluster dots (Ag₂₉–0D). In the presence of Cs⁺ cations, the Ag₂₉(SSR)₁₂ nano-building blocks are selectively assembled into distinct arrays with different oxygen-carrying solvent molecules―Cs@Ag₂₉(SSR)₁₂(DMF)_x as 1D linear chains (Ag₂₉–1D), Cs@Ag₂₉(SSR)₁₂(NMP)_x as 2D grid networks (Ag₂₉–2D), and Cs@Ag₂₉(SSR)₁₂(TMS)_x as 3D superstructures (Ag₂₉–3D). Such self-assemblies of these Ag₂₉(SSR)₁₂ units have not only been observed in their crystalline state, but also in their amorphous state. Due to the diverse surface structures and crystalline packing modes, these Ag₂₉-based assemblies manifest distinguishable optical absorptions and emissions in both solutions and crystallized films. Furthermore, the surface areas of the nanocluster crystals are evaluated, the maximum value of which occurs when the cluster nano-building blocks are assembled into 2D arrays (i.e. Ag₂₉–2D). Overall, this work presents an exciting example of the hierarchical assembly of atomically precise nanoclusters by simply controlling the adsorbed molecules on the cluster surface.     

继往开来,鹏抟九天——靖继鹏先生情报学思想大观

[目的/意义]靖继鹏先生是我国情报学界的著名专家,其思域广阔,著作等身,对其思想视界进行梳理和透视,有助于启发后学晚辈,推动情报学研究稳步前进和创新发展。[方法/过程]运用访谈、文献调研等方法,对先生的学术研究成果及管理实践进行研读与梳理,从治学、育人、管理和办刊4个方面总结和探讨先生的思想贡献。[结果/结论]先生的四重思想大观,折射出有机整体观、可持续发展观、科学观、实践观、贯通观、系统观、历史观和角色观等丰富的哲学思维,具有十分重大的借鉴意义。