ChemInform Abstract: A Fully Size-Resolved Perspective on the Crystallization of Water Clusters.

Precisely size-selected (H₂O)_n clusters (n = 85—457) are characterized by IR spectroscopy.     

Navigating the Future of Separation Science Education: A Perspective

Chromatographia - A number of recommendations on how to improve the education and training of separation scientists were recently made by the National Academies of Sciences, Engineering, and...     

基于科学论证视角的职前科学教师培养研究述评

目前基于科学论证的教学设计研究成果缺乏,且科学教师论证水平普遍较低,且未养成习惯。通过文献法,关注国际本主题相关实证研究成果,发现职前科学教师对科学论证具有不同的理解,科学论证对职前科学教师科学本质观、科学概念和论证能力有影响。基于文献总结,从培养论证能力的专业课程设置、社会性科学议题教学和学科知识强化等3个方面提出建议。     

启蒙视野下的中国科幻小说发展流变

20世纪中国科幻小说创作呈现出科学观窄化、科技美学不张及人文哲理思考空间受限等不足,这源于将科学幻想作为民族国家启蒙的工具,以及前工业化时代的社会现实。20世纪八九十年代出现了以科技为中心的“人学”转向,新世纪则具备了较为成熟的出版平台和作家群体,二者促成了新世纪中国科幻小说新质的发生。表现为：一,开启了主流文学未竟的工业现代性启蒙之路,深化了现代性思考,建构起技术诗学这一新美学维度及以科技为轴的新历史维度,形成独特的“中国标识”;二,生成了后现代社会启蒙与世俗享乐主义的新价值体系。由于主流文学与科幻小说的长期隔阂,致使科幻小说的启蒙思考难以形成对主流文学启蒙观的补充,如何消除隔阂,确立科幻小说的文学价值和地位,任重而道远。     

从诺贝尔奖看高分子百年*

从高分子学科确立到现在已经经历了整整一个世纪。围绕高分子领域的历次诺贝尔奖,重点回顾了“高分子”概念的确立、高分子合成化学、高分子理论、功能高分子等领域的里程碑事件,分析了高分子学科的未来发展趋势。     

从百年诺贝尔科学奖看有机合成的发展

统计百年来诺贝尔科学奖发现，有机合成化学发展经历了经典有机合成阶段、有机合成艺术阶段和科学设计阶段，预示着有机合成将继续在新试剂、新反应、新方法、新理论的发现等方面取得很大的发展，在化学生物学、分子工程和绿色化学领域里有广阔的前景。     

大型仪器科学管理(204~208)从管理学角度看生命科学机构的仪器平台管理

当前, 生命科学机构的仪器平台管理均以经验为主, 在实际管理过程中产生了一些问题, 需要从管理学角度进行分析和解决.首先借鉴互联网平台的概念, 对仪器平台的组织构架进行分析, 再对仪器平台与科研团队的关系进行经济学分析, 指出生命科学学科思维框架下, 仪器平台工作人员需要了解管理活动自身的特点, 最后建议在研究机构的组织构架中给予仪器平台独立并与科研团队平行的定位.同时, 提出仪器使用价格应采取浮动机制, 仪器平台工作人员和管理者的培养、选择必须以提高管理能力为出发点, 并给出相关措施.     

A New Many-Body Expansion Scheme for Atomic Clusters: Application to Nitrogen Clusters

Although the many-body expansion (MBE) approach is widely applied to estimate the energy of large systems containing weak interactions, it is inapplicable to calculating the energies of covalent or metal clusters. In this work, we propose an interaction many-body expansion (IMBE) to calculate the energy of atomic clusters containing covalent bonds. In this approach, the energy of a system is expressed as the sum of the energy of atoms and the interaction energy between the atom and its surrounding atoms. The IMBE method is first applied to calculate the energies of nitrogen clusters, in which the interatomic interactions are truncated to four-body terms. The results show that the IMBE approach could significantly reduce the energy error for nitrogen clusters compared with the traditional MBE method. The weak size and structure dependence of the IMBE error with respect to DFT calculations indicates the IMBE method has good potential application in estimating energy of large covalent systems.     

印刷技术发展的回顾与展望

从单纯的技术角度,印刷可以定义为是通过选择性添加适当物质的方法将拟表达的信息、内容或功能呈现在适当载体上的过程,属于典型的附加型、面处理(并行处理)技术范畴,具有空间分辨率高、生产效率高和成本低的特点.正是由于这些特质,印刷是开创现代文明的重要载体,也是人类文明历史上最重要、历史最悠久的传媒技术,今天又在表面装饰、印刷电子、超高规模集成电路制备等领域得到广泛应用.作为传媒技术,印刷的核心作用是可视化,因此将适当呈色剂放置在适当载体上成为技术关键;在表面装饰和印刷电子领域中,印刷的作用是将适当功能单元(如,防护、装饰、电子或光电子功能单元)选择性放置在适当载体上,以满足装饰或/和某种功能的需要;在超高规模集成电路领域,印刷的作用主要体现在表面微加工,核心是印刷技术拥有的微纳米加工的能力.本文也是从这个几个方面,对印刷技术在过去几千年的发展历程和今后的发展趋势有一个概略的回顾和展望.     

A Personal Perspective on the Rise of MTDSC

Journal of Thermal Analysis and Calorimetry -     

Studies on NaXe Clusters

In this paper all NaCl crystal samples containing metallic sodium colloids used in experiments were cleaved to ~1mm thickness from a block of NaCl single crystal at room temperature1,2. Two parallel large surfaces of each crystal were polished. Then these NaCl crystal specimens were implanted at 10-6 Torr with xenon ions using an accelerating voltage of 36 keV. The xenon ion fluences were in the range from 1(1015/cm2 to 7(1017/cm2. The chemical shifts of 23Na in these NaCl crystal specime…     

A New Two-dimensional Coordination Polymer Based on Trinuclear Manganese Clusters

A novel two-dimensional Mn（II） coordination polymer, [Mn3（L）R（cis-chdc）fftrans- chdc）]n （L = 2-amino-4-（1H-imidazo[4,5-J][1,10]phenanthrolin-2-yl）phenol and chdc = 1,4-cyclo- hexanedicarboxylate）, has been hydrothermally synthesized and characterized by elemental analysis, IR, TG PL and single-crystal X-ray diffraction. Crystallographic data for this compound： monoclinic space group P2/n with a = 11.0058（13）, b = 9.0179（11）, c = 28.431（3） A, β = 92.850（2）°, V = 2818.3（6） A3, Z = 2, C62Hs6Mn3N10O14, Mr = 1329.99, Dc = 1.567 g/cm3, F（000） = 1370, p（MoKa） = 0.742 mm-1, R = 0.0553 and wR = 0.1421. The chdc carboxylates bridge the Mn（II） atoms to form a trinuclear Mn（lI） cluster. The cis-chdc ligands are held together by the trinuclear Mn（II） clusters to result in a chain structure. Further, the trans-chdc ligands link adjacent chains to furnish a two-dimensional network. The π-π interactions between neighboring layers link the adjacent layers into a three-dimensional supramolecular architecture. Moreover, the N-H...O and O-H...O hydrogen bonds further stabilize the 3D supramolecular architecture.     

ChemInform Abstract: Local Density Functional Study of Copper Clusters: A Comparison Between Real Clusters,Model Surface Clusters,and the Actual Metal Surface.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

科学概念转变教学的效果论证*——基于元分析的国际比较视角

采用元分析的方法,以化学内容主题为例,综合探索2000-2018年间英文期刊中概念转变的实验研究和准实验研究的效果。根据入选标准和极值筛查,得到60个有效研究。采用CMA2.0软件分析数据,结果发现19年来科学概念转变研究的整体效果显著;类比思维类、情意教学类、学习方式类、教学媒体类等4类概念转变策略的效果差异显著,但都是有效的策略和方法。     

A Density Functional Investigation of Fluorinated Silicon Clusters

Density functional calculations have been carried out on a series of fluorinated empty cages X_nF_n(n=2–20) with X?Si, Ge, and Sn. It indicates that the fullerene‐like cage structure with pentagons turns out to be the most stable with n increasing, and the stability of the X_nF_n isomers increases with the number of five‐membered rings. The HOMO‐LUMO gap for Ge (n=6, 10) cages is found to be even larger than the values for Si cages, though in bulk Ge has a smaller band gap than Si. Moreover, calculation of the Gibbs free energy of oligomerization reaction of SiF→1/n (SiF)_n showed that this reaction is exothermic even at 900 K, indicating the favorability of their formation from the SiF monomer.     

A Quantum-Chemical Study of Dissociation of H2 Molecule on Palladium Clusters

The mechanism of the reaction of Pd _n clusters with an H₂ molecule was suggested on the basis of DFT B3LYP/HW calculations. The catalytic center in an elementary event of the process is one of the vertices of the Pd _n cluster; spillover of hydrogen atoms along the cluster edges results in the formation of a stable Pd _n H₂ complex with a significant energy gain in the case of the singlet reaction channel. In such a mechanism, the cluster size should not significantly affect the reaction up to a certain moment; therefore, when simulating processes involving large clusters, we can restrict ourselves to relatively small sites of their surface.