从科技竞赛获奖作品分析化学研究性学习选题的科学性

统计分析了近11届（2007-2017年）全国青少年科技创新大赛中化学参赛项目以及荣获一等奖的项目在化学二级学科中的分布情况，结果显示：涉及交叉学科的材料化学专业获奖项目数量和质量占据的比例越来越大，有机化学和物理化学也是中学生探究课题的热门方向，获奖项目数量仅次于材料化学。基于分析数据，总结了各二级学科中学生选题较为集中的研究领域，并对教师指导学生开展研究性学习选题的思路和方法提出了建议。     

含铥金属富勒烯的生成及其特殊的溶解行为

金属富勒烯的合成及结构研究是当前富勒烯化学研究的重要内容[1]．一些稀土金属元素，如Sc[2]、Y[3]及大部分斓系元素（La、Ce、Nd、Sin、Eu、Gd、Tb、Ho）[4]形成的金属富勒烯已被合成出来．但仍有一些稀土富勒烯的合成尚未见报道，使人们难以对金属富勒烯的形成机制及物化性能作出全面的判断．本文采用原位活化、交换电极回放电弧放电及两步提取法首次得到含锡金属富勒烯．通过空白对比实验确定了Tin＠C。怕9生成．对甲苯及毗院提取液的质谱研究表明含镀金属富勒烯具有区别于其它金属富勒烯的特殊的溶解性能，显示出其可能具有独特的…     

室温固态反应制备纳米Ba1－xSrxTiO3固溶体及其结构与介电性能研究

采用室温固态反应合成了一系列Ba_1－xSr_xTiO₃固溶体纳米粉末(0≤x≤1.0). 经XRD物相分析和d-间距-组成图证明, 产品为立方晶系的完全互溶取代固溶体. TEM形貌观察, 粒子基本为球形, 平均粒径40 nm. 该方法具有产率高, 无需溶剂, 对环境无污染等优点. 通过制陶实验, 分别测定了该系列固溶体的室温介电常数、介电损失以及介电常数随温度的变化. 结果发现, 采用室温固态反应在BaTiO₃中掺入适量锶, 由于掺杂离子均匀进入母体晶格, 引起居里点降低, 室温介电常数达11000以上, 介电损耗由BaTiO₃纯相的0.03 (3%)降为0.008 (0.8%). 纳米粉体的烧结温度为1180 ℃, 比传统微米级粉体的烧结温度降低100～150 ℃.     

On the Possibility of Using the Jellium Model as a Guide To Design Bimetallic Superalkali Cations

The potential application of the jellium model as guidance in the rational design of bimetallic superalkali cations is examined under gradient-corrected density functional theory for the first time. By using Li, Mg, and Al as atomic building blocks, a series of bimetallic cationic clusters with 2, 8, 20, and 40 valence electrons are obtained and investigated. As the corresponding neutral clusters tend to lose one valence electron to achieve closed-shell states in the jellium model, these studied cations exhibit much lower vertical electron affinities (EA_vert, 3.42–4.95 eV) than the ionization energies (IEs) of alkali metal atoms, indicating their superalkali identities. The high stability of these cationic clusters is guaranteed by their considerable HOMO–LUMO gaps and binding energies per atom. Moreover, the feasibility of using the designed superalkalis as efficient reductants to activate CO₂ and N₂ molecules and as stable building blocks to assemble ionic superatom compounds is explored. Therefore, this study may provide an effective method for obtaining various metallic superatoms with extensive applications on the basis of the simple jellium rule.     

建构学习仪式感 提升学习主动性*——以元素化学学习为例

结合元素化学课程特色和当代大学生心理性格特征,提出以学生为主体、提升学生素养能力为重点,构建元素代言人、身边的化学(现象、实验)、翻转课堂等一系列课内外学习活动,以学习活动的仪式感促进学生进行自我暗示,塑造愉悦学习的情境,克服焦虑厌学的情绪,提升学生学习的主动性,并以学科育人的思想贯穿课程始终,营造有形有实、充满活力的元素化学课堂。     

金属镍配合物的合成及其在烯烃异构化反应中的应用*

设计了一个无机化学教学实验,内容包括:(1)催化剂前体Ni[P(OEt)3]4的合成;(2)无水无氧条件下原位生成催化剂HNiL+3[L=P(OEt)3]及2-丙烯基苯的异构化反应。实验中使用高效液相色谱仪检测烯烃异构化反应的结果,并推测了异构化反应可能的机理。根据学生的实验数据,深入地分析了影响合成催化剂前体产率和烯烃异构化反应转化率的因素。该实验能够使学生在无水无氧操作、低温反应、微量反应的控制等方面得到训练,并且能够掌握高效液相色谱仪的使用原理和测试方法。     

Study of low momentum track reconstruction for the BESⅢ main drift chamber

In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESⅢ Main Drift Chamber(MDC),a specialized method called TCurlFinder was developed.This tracking method focuses on the charged track reconstruction under 120 MeV and possesses a special mechanism to reject background noise hits.The performance of the package has been carefully checked and tuned by both Monte Carlo data and real data.The study shows that this tracking method could obviously enhance the reconstruction efficiency in the low transverse momentum region,providing physics analysis with more and reliable data.     

Co含量对Bi6Fe2-xCoxTi3O18样品多铁性的影响

用固相工艺制备了Bi₆Fe_2-xCo_xTi₃O₁₈ (BFCT-x, x=0, 0.2, 0.6, 0.8, 1.0, 1.2, 1.6, 1.8, 和2.0)多铁陶瓷样品, 样品X射线谱分析发现, 随着Co含量的增加, 样品晶格常数出现了先增大后减小的变化. 室温下, BFCT-0.6样品呈现出相对较高的饱和磁化强度, 2M_s约为4.49 emu/g, BFCT-1.0具有最高的剩余磁化强度, 2M_r约为0.89 emu/g. Co含量在0.2 ≤x≤qslant 1.2范围内, 随着Co含量的增加样品顺磁–铁磁相变温度从752 K降至372 K. 小量的Co改善了样品的铁电性能, 当x=0.6时样品样品的铁电性能最佳, 随着含量增大样品铁电性能下降, 但当x >1.2时样品的铁电性能又得到了改善.     

Fabrication of LSM-SDC composite cathodes for intermediate-temperature solid oxide fuel cells

Microstructure, interfacial resistance, and activation energy for composite cathodes consisting of 50 wt% (La_0.85Sr_0.15)_0.9MnO_3-δ (LSM) and 50 wt% Sm_0.2Ce_0.8O_1.90 (SDC) were studied for intermediate-temperature solid oxide fuel cells based on SDC electrolytes. Microstructure and interfacial resistance were greatly influenced by the characteristics of starting powder and temperatures sintering the electrodes. Optimum sintering temperatures were 1100 and 950 °C, respectively, for electrodes with SDC prepared using oxalate coprecipitation technique (OCP) and glycine-nitrate process (GNP). Area-specific resistances determined using impedance spectroscopy were 0.47 and 0.92 Ω cm² at 800 °C for LSM-SDC/OCP and LSM-SDC/GNP, respectively. The high electrochemical performance is attributed to small grain size, high porosity, and high in-plane electrical conductivity of composite cathode, demonstrating the dramatic effects of microstructure on electrode performance. To increase the electrode performance, it is critical to enhance the diffusion rate of oxygen species.