“位”“构”“性”统领下的单元整体教学设计与实践——以人教版高中化学选择性必修2“原子结构与元素的性质”为例

本文通过对《普通高中化学课程标准(2017年版2022年修订)》及多版本教材的对比分析,确定“原子结构与元素的性质”主题的认识方式,围绕“位”“构”“性”关系的大概念和教学目标,选择合适的情境素材,在真实问题“对角线上的元素性质如何比较”的解决过程中巧妙衔接,形成单元整体教学,发展了学生建立基于“位”“构”“性”关系的系统思维框架,促进了学生化学学科核心素养的发展。

研高考习题,建“位-构-性”知识网络——以2014-2016年高考全国卷Ⅰ为背景

元素周期律与元素周期表知识不仅是化学学习的重要工具,更是高考的"宠儿",本文以2014-2016年高考全国卷Ⅰ为背景,通过常见考点归纳、基础知识梳理、"位-构-性"知识网络的构建,从而帮助考生轻松拿下元素周期律和元素周期表试题,做到"元素周期表在左,元素周期律在右,走在化学学习和高考的两旁,随时撒种,随时开花"。

广东高考化学“位”“构”“性”关系考点解析

本课题研究的是广东高考化学"位""构""性"关系考点解析。物质结构,元素周期律是中学化学的基本理论之一,也是高考的必考内容之一。要求理解并熟记主族元素的原子结构,同周期、同主族元素的性质递变规律及元素周期表的结构,理解三者之间的内在联系。高考题中主要以元素推断题出现,旨在考查考生的分析推断能力。

凸显模型建构 落实核心素养——以“元素周期律”教学设计为例

一、教材分析“元素周期律”是高中化学知识体系中重要的理论基础,其核心为元素性质的周期性变化规律及其应用,该课程内容揭示了原子结构与元素性质之间的关联,既是对已有元素化合物归纳总结,又是对未知元素化合物的发现理论指导,是学生建构完整知识结构的重要支撑。从科学方法角度看,本节课通过“提出问题——实验设计与验证——得出结论”的探究思路,帮助学生形成科学研究的一般思路和方法,建立元素的认识模型。从学科能力角度看,本节课借助实验和事实,发展学生归纳、演绎、证据推理、模型认知与建构等的科学探究能力、逻辑思维能力以及迁移能力。

在自主建构中深度认识非金属元素的研究思路--以卤族元素为例

以“位—构—性”思维模型为指引,充分发挥元素周期表的预测功能。基于卤族元素的位置和结构特点,引导学生对卤族元素的非金属性和对应单质的氧化性进行推断和预测,并设计实验验证,从而实现学生对卤族元素性质的意义建构,充分发挥学生的主体性,发展并提升学生证据推理与模型认知素养。

利用“位—构—性”推断元素的方法分析

元素的推断问题是高考中的热点问题,立意能力,考查基础,通过上挂下联,分化整合,可形成综合性问题,需要学生在熟知元素结构、常见单质、化合物的特性、元素周期表中规律,才能正确解答.利用元素的位构性之间的关系,对已知元素原子(离子)的核外电子排布、已知单质或化合物的特性、已知元素在周期表中的位置三类问题,通过例题进行详解总结解题的一般规律,指出了解答这类问题的一般方法.

Transition metal coordination polymers with flexible dicarboxylate ligand:Synthesis,characterization,and photoluminescence property

Under solvothermal conditions,six new coordination polymers(CPs)[Mn(L)(phen)(H_(2)O)]_(n)(1),[Co(L)(phen)(H_(2)O)]_(n)(2),[Cu(L)(phen)(H_(2)O)]_(n)(3),[Zn_(2)(L)_(2)(phen)2(H_(2)O)]_(n)(4),[Zn(L)(phen)]_(n)(5),and[Cd(L)(phen)2]_(n)(6)were synthesized by reactions of dicarboxylate ligand 2,2'-(1,2-phenylenebis(methylene))bis(sulfanediyl)dinobutyric acid(H_(2)L)and 1,10-phenanthroline(phen)with the corresponding metal salts.Complexes 1-6 have been structurally characterized by single-crystal X-ray diffraction analyses,elemental analysis,IR,thermogravimetric analysis,and powder X-ray diffraction.The structures of 1-6 are 1D chains,which are further connected by hydrogen bonding interac-tions to form 3D supramolecular structures.Among them,1 and 2 are isomorphic with L2-of syn-conformation,while L2-shows anti-conformation in 3-6.In addition,the solid-state photoluminescence property of 4-6 was investigated.

点击广东高考对元素周期律(表)的考查

元素周期律是高考热门考点,元素位构性间的相互推断是考查物质结构、元素周期律（表）、元素性质的重要题型,同时也是培养学生综合分析、逻辑推理、迁移应用等思维能力的常用手段.该类题型涉及知识面广,综合性强,除了考查以“位、构、性”关系推断元素外,还易于元素化合物知识、化学计算、基本理论问题等结合起来综合考查.在近四年的高考中均占4％～6％的分值,同时,元素周期律也是梳理元素化合物性质的重要工具,在复习中应加倍重视.

Allozyme Diversity and Population Genetic Structure of Three Medicinal Epimedium Species from Hubei

Three Epimedium species, E. pubescens Maxim., E. sagittatum （Sieb. ＆ Zucc.） Maxim., and E. wushanense T. S. Ying, which are sympatrically distributed in the western Hubei Province, have been used in traditional Chinese medicine （TCM） for about 2,000 years. Genetic variability and population genetic structure of 11 natural populations of these Epimedium species were investigated using isoelectric focusing in thin-layer polyacrylamide slab gels. Of the 22 enzyme systems prescreened, six coding for 13 loci and 45 alleles were resolved, which were used for analyzing genetic diversity and population structure at both intraspecific and interspecific levels. The results showed that： l） high levels of genetic diversity were observed in all three species （A = 2.6-3.2, P = 69.2%-84.6%, Ho= 0.274-0.377, HE= 0.282-0.369）, which were higher than that of other herbaceous and aulmal-pollinated species with similar life-history characteristics; 2） there was significant deviation from Hardy-Weinberg Equilibrium, with one half of the loci showing heterozygote excess and the other homozygote excess, in all populations, suggesting the complicated breeding system of Epimedium species; 3） the low level of intraspecific and interspecific genetic differentiation （GST= 0.0246-0.0409 and 0.0495-0.1213, respectively） indicated a high level of gene flow among populations and close genetic relationship among the three species; and 4） UPGMA cluster analysis further showed that E. pubescens was more closely related to E. sagittatum than to E. wushanense, which was in good agreement with the morphological characters and the recent phylogenetic analysis of these species. On the basis of these results, it was concluded that the mixed breeding system, long-lived perennial life form, ancient evolutionary history, and seed dispersal by ants in Epimedium are responsible for the genetic variation and population structure of these species.

Primary-transient creep and anelastic backflow of pure copper deformed at low temperatures and ultra-low strain rates

Creep and anelastic backflow behaviors of pure copper （4N Cu） with grain size dg=40 μm were investigated at low temperatures of T〈0.3Tm （Tm is melting point） and ultra-low creep rates of ε≤1×10^-10 s^-1 by a high strain-resolution measurement （the helicoid spring specimen technique）. Analysis of creep data was based on the scaling factors of creep curves instead of the conventional extrapolated steady-state creep rate. Power-law creep equation is suggested to be the best for describing the primary transient creep behavior, because the pre-parameter does not apparently change with elapsed time. The observed anelastic strains are 1/6 of the calculated elastic strains, and linear viscous behavior was identified from the logarithm plot of the anelastic strain rate versus anelastic strain （slope equals 1）. Therefore, the creep anelasticity is suggested to be due to the unbowing of there-dimensional network of dislocations.

Micro-displacement amplifying mechanism driven by piezoelectric actuator

Piezoelectric actuator has high stiffness, high frequency and infinite control precision, but a short output displacement which is often 1/1 000 of its length. In order to meet the requirements that tools feeding should be long-travel, high-frequency and high-precision in non-circular precision turning, a new one-freedom flexure hinge structure is put forward to amplify the output displacement of piezoelectric actuator. Theoretical analysis is done on the static and dynamic characteristics of the structure, differential equations are presented, and it is also verified by the finite element method. It's proved by experiments that the output displacement of the structure is 293 μm and its resonant frequency is 312 Hz.

“对角线规则”教学内容的挖掘与拓展

通过梳理初、高中教材"对角线规则"相关知识,明确各阶段学生需达到的进阶目标和思维层级;简述"对角线规则"在近年高考试题中的应用,说明对角线规则对推理预测陌生元素性质的重要作用。补充教材中位于对角线上的元素"锂-镁、铍-铝、硼-硅"性质的相似之处,并拓展至"碳-磷、氮-硫、氧-氯"元素,于深度和广度上挖掘和拓展"对角线规则",帮助学生建立完整的元素周期律体系,培养基于"位-构-性"认知模型分析复杂问题的能力。

Electronic and geometric structure of the copper-ceria interface on Cu/CeO2 catalysts

The atomic structure of the active sites in Cu/CeO2 catalysts is intimately associated with the copper-ceria interaction. Both the shape of ceria and the loading of copper affect the chemical bonding of copper species on ceria surfaces and the electronic and geometric character of the relevant interfaces. Nanostructured ceria, including particles(polyhedra), rods, and cubes, provides anchoring sites for the copper species. The atomic arrangements and chemical properties of the(111),(110) and(100) facets, preferentially exposed depending on the shape of ceria, govern the copper-ceria interactions and in turn determine their catalytic properties. Also, the metal loading significantly influences the dispersion of copper species on ceria with a specific shape, forming copper layers, clusters, and nanoparticles. Lower copper contents result in copper monolayers and/or bilayers while higher copper loadings lead to multi-layered clusters and faceted particles. The active sites are usually generated via interactions between the copper atoms in the metal species and the oxygen vacancies on ceria, which is closely linked to the number and density of surface oxygen vacancies dominated by the shape of ceria.

Microstructures,tensile properties and serrated flow of Al_xCrMnFeCoNi high entropy alloys

Microstructures and mechanical properties of dual-phase AlxCrMnFeCoNi (x=0.4, 0.5, 0.6, at.%) alloys were investigated. Thermomechanical processing leads to a microstructural evolution from cast dendritic structures to equiaxed ones, consisting of face-centered cubic (fcc) and body-centered cubic (bcc) phases in the two states. The volume fraction of bcc phase increases and the size of fcc grain decreases with increasing Al content, resulting in remarkably improved tensile strength. Specifically, the serrated flow occurring at the medium temperatures varies from type A+B to B+C or C as the testing temperature increases. The average serration amplitude of these Al-containing alloys is larger than that of CoCrFeNiMn alloy due to the enhanced pinning effect. The early small strain produces low-density of dislocation arrays and bowed dislocations in fcc grains while the dislocation climb and shearing mechanism dominate inside bcc grains. The cross-slip and kinks of dislocations are frequently observed and high-density-tangled dislocations lead to dislocation cells after plastic deformation with a high strain.

Impact of Oxygen Vacancy on Band Structure Engineering of n-p Codoped Anatase TiO2

Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i.e. V-N and Cr-C） and non-compensated （i.e. V-C and Cr-N） codoped anatase TiO2 by performing extensive density functional theory calculations. Theoretical results show that oxygen vacancy prefers to the neighboring site of metal dopant （i.e. V or Cr atom）. After introduction of oxygen vacancy, the unoccupied impurity bands located within band gap of these codoped TiO2 will be filled with electrons, and the posi- tion of conduction band offset does not change obviously, which result in the reduction of photoinduced carrier recombination and the good performance for hydrogen production via water splitting. Moreover, we find that oxygen vacancy is easily introduced in V-N codoped TiO2 under O-poor condition. These theoretical insights are helpful for designing codoped TiO2 with high photoelectrochemical performance.

Heterogeneous N-coordinated single-atom photocatalysts and electrocatalysts

Single-atom catalysts(SACs)have been widely used in heterogeneous catalysis owing to the maximum utilization of metal-active sites with controlled structures and well-defined locations.Upon tailored coordination with nitrogen atom,the metal-nitrogen(M-N)-based SACs have demonstrated interesting physical,optical and electronic properties and have become intense in photocatalysis and electrocatalysis in the past decade.Despite substantial efforts in constructing various M–N-based SACs,the principles for modulating the intrinsic photocatalytic and electrocatalytic performance of their active sites and catalytic mechanism have not been sufficiently studied.Herein,the present review intends to shed some light on recent research made in studying the correlation between intrinsic electronic structure,catalytic mechanism,single-metal atom(SMA)confinement and their photocatalytic and electrocatalytic activities(conversion,selectivity,stability and etc).Based on the analysis of fundamentals of M–N-based SACs,theoretical calculations and experimental investigations,including synthetic methods and characterization techniques,are both included to provide an integral understanding of the underlying mechanisms behind improved coordination structure and observed activity.Finally,the challenges and perspectives for constructing highly active M–N based photocatalysis and electrocatalysis SACs are provided.In particular,extensive technical and mechanism aspects are thoroughly discussed,summarized and analyzed for promoting further advancement of M-N-based SACs in photocatalysis and electrocatalysis.

基于学科理解的高中化学教学设计——以“元素周期表”为例

基于学科理解的视角分析人教版普通高中化学教科书必修第一册(2019年6月第1版)第四章的“原子结构与元素周期表”和“元素周期律”的内容,以“元素周期表”为例对如何准确把握化学史内涵和价值进行学科理解、教学设计和教学实践,引导学生逐步建构“位”“构”“性”认识模型,增进对化学学科思维的理解。

Interactions Between Anticancer Pt(II) complexes and Human Erythrocyte Spectrin *

The interactions between human erythrocyte spectrin(SP) and Pt(II) complexes with different composition and configuration were studied by fluorescence and circular dichroism spectra. The results showed that there are 4.7×10 2 binding sites of cisplatin(CDDP) in a spectrin tetramer(SPT). Among them, about 70 sites with apparent binding constant K 1】3.47×10 6 were of highest affinity, 1.8×10 2 sites with K 2 = 3.47×10 6 were of high affinity, and other 2.2×10 2 sites with K 3 = 8.77×10 5 were of low affinity. The conformation change of spectrin, depending on the concentration of Pt(II) complex and molar ratio(R) of Pt(II) complex to spectrin, was induced by the binding of Pt(II) complexes. It indicated that the interaction of both CDDP and cis diaquodiamine platinum(DADP) with SP followed a two step first order kinetic process in the first stage (1 h), and the kinetic constants were determined. In the second stage, the induced conformation change, polymerization and depolymerization of SP were probably involved. It was noticed that in the reaction of SP and Pt(II) complexes with 1,2 cyclohexanediammine isomers as chiral carrier ligand, stereo matching played a more important role than the affinity of Pt(II) to thiol groups of SP.

Mechanical properties and fracture mechanism of as-cast MnFeCoCuNix high-entropy alloys

MnFeCoCuNix high-entropy alloys(HEAs)with different Ni contents were fabricated by vacuum induction melting.XRD and SEM−EDS were used to analyze the phase constitution and structure,and the tensile properties of the samples were determined using a universal tensile tester.The results show that the HEAs consist of a dual-phase structure,in which FCC1 phase is rich in Fe and Co,while the FCC2 phase has high contents of Cu and Mn.As Ni content increases,the segregation of Cu decreases,accompanied by the decrease of FCC2 phase.Moreover,the tensile strength of the HEAs increases first and then decreases,and the elongation increases slightly.This is attributed to the combined effect of interface strengthening and solid solution strengthening.The in-situ stretched MnFeCoCuNi0.5 alloy shows obvious neck shrinkage during the tensile fracture process.In the initial deformation stage,the slip lines show different morphologies in the dual-phase structure.However,in the later stage,the surface slip lines become longer and denser due to the redistribution of atoms and the re-separation of the dissolved phase.

Domain adaptive methods for device diversity in indoor localization

To solve the problem of variations in radio frequency characteristics among different devices,transfer learning is applied to transform device diversity to domain adaptation in the indoor localization algorithm.A robust indoor localization algorithm based on the aligned fingerprints and ensemble learning called correlation alignment for localization(CALoc)is proposed with low computational complexity.The second-order statistical properties of fingerprints in the offline and online phase are needed to be aligned.The real-time online calibration method mitigates the impact of device heterogeneity largely.Without any time-consuming deep learning retraining process,CALoc online only needs 0.11 s.The effectiveness and efficiency of CALoc are verified by realistic experiments.The results show that compared to the traditional algorithms,a significant performance gain is achieved and that it achieves better positioning accuracy with a 19%improvement.