Lanthanoid Antimonides Ln2Sb5 (Ln = Sm,Gd, Tb,Dy) and Rationalization of Chemical Bonding within the Antimony Polyanion by Combining the Zintl‐Klemm Concept with Bond‐Length Bond‐Strength Relationships

The title compounds are formed by peritectic reactions. Single crystals could be isolated from samples with high antimony content. Their structure was determined for Dy₂Sb₅ from four‐circle X‐ray diffractometer data: P2₁/m, a = 1306.6(1) pm, b = 416.27(4) pm, c = 1458.4(1) pm, β = 102.213(8)°, Z = 4, R = 0.061 for 2980 structure factors and 86 variable parameters. All dysprosium atoms have nine antimony neighbors forming tricapped trigonal prisms with Dy–Sb distances varying between 308 and 338 pm. The antimony atoms occupy ten different sites with greatly varying coordination. One extreme case is an antimony atom surrounded only by dysprosium atoms in trigonal prismatic arrangement, the other one is an antimony atom in distorted octahedral antimony coordination. The various antimony‐antimony interactions (with Sb–Sb distances varying between 284 and 338 pm) are rationalized by combining the Zintl‐Klemm concept with bond‐length bond‐strength considerations.     

概念转变理论的发展及面临的挑战

经过30年的发展,经典概念转变理论的内涵已发生了变化。通过对概念转变理论发展历程的分析,总结了概念转变研究的视角、研究的共识和研究的争议,指出当前概念转变研究面临3方面的挑战:寻找概念转变有效证据的研究方法;如何将成功的概念转变策略引入课堂教学实践;要进一步明确"概念转变"的含义。     

试论化学核心素养的结构

化学核心素养包含了“化学”的素养、“核心”的素养、“人”的素养三重意蕴。基于对化学核心素养的概念分析和层次分析,提出其四维度结构模型。在4个维度中,“化学基本观念”是基础维度,“化学过程”和“化学在生活中的应用”是2个活化维度,“对化学的态度”是动力维度。化学核心素养为学术性化学素养和生活性化学素养的发展同时奠定了基础。把握3种化学素养在结构和具体维度上的差异有助于理解化学核心素养的内涵,也有助于把握中学化学课程中不同模块的教学定位。     

离子反应中几个问题的质疑

对离子反应的概念、离子反应的实质、离子方程式表示的意义及离子方程式的书写步骤产生质疑,指出这些问题并纠正。     

基于元素观的专题式复习教学法在高职有机化学教学中的应用

采用专题式复习教学法对高职有机化学进行教学。教学过程设计主要分为专题问题、专题导读、专题讨论、专题总结、专题升华等5个步骤。结果显示效果良好,并能使学生建立化学观念,有效提高学生的化学素养。     

关于气相色谱比保留体积概念问题的商榷

提出气相色谱中所谓校正到273．15K的“比保留体积”的定义是不科学的,也是没有必要的。分析了问题产生的原因和可能带来的影响。     

PGraphD*: Methods for Drift Detection and Localisation Using Deep Learning Modelling of Business Processes

This paper presents a set of methods, jointly called PGraphD*, which includes two new methods (PGraphDD-QM and PGraphDD-SS) for drift detection and one new method (PGraphDL) for drift localisation in business processes. The methods are based on deep learning and graphs, with PGraphDD-QM and PGraphDD-SS employing a quality metric and a similarity score for detecting drifts, respectively. According to experimental results, PGraphDD-SS outperforms PGraphDD-QM in drift detection, achieving an accuracy score of 100% over the majority of synthetic logs and an accuracy score of 80% over a complex real-life log. Furthermore, PGraphDD-SS detects drifts with delays that are 59% shorter on average compared to the best performing state-of-the-art method.     

钾元素概念的发展史及其意义

通过对钾元素概念的发展史考证分析可知,钾是电化学兴起后最先发现的活泼金属。19世纪初,随着科学思想和实验条件的发展,通过电解法首次制取到钾的单质,但并未确定为元素。19世纪中期,对钾元素性质的实验验证和原子论的发展,使得钾元素的概念被确认。20世纪20年代,钾元素同位素的发现,形成了现代的钾元素概念。钾元素概念的发展史不仅是元素概念的发展史,也是科学方法的发展史与科学思想的演变史。     

The LPS concept, a new way to look at anionic conductors

A new approach to anionic conduction is presented, and illustrated using already well-known anion conductors, as well as the recently discovered fast oxide-ion conductor La₂Mo₂O₉. The so-called LPS (lone-pair substitution) concept could be used to seek for novel families of anion conductors, issued from already known compounds with lone-pair elements. It is based on the similarity in volume between an electronic lone pair and oxide or fluoride anions, and on the vacancy created by the replacement of a lone-pair by a non-lone-pair cation. A tentative list of the most appropriate substituting elements for given lone-pair cations is presented.