“基地班”用英语授课的体会

当今世界是一个开放的世界 ,经济的国际化及科技的全球化缩小了地域间及人与人之间的距离 ,一个全球化的高科技经济时代和信息时代已经到来。我们培养的学生将是 2 1世纪的建设者和接班人 ,他们担负着民族强盛和国家兴旺的重任 ,他们应是基础扎实、知识面广、学有专长、具有良好的自主能力和心理素质的创新性人才。在未来传承文明、沟通信息、开展合作与交流、参与国际竞争中 ,英语是主要的交流工具之一。社会对专业人才的外语水平提出了更高的要求。因此 ,我们培养的学生应具备很强的英语听、说、读、写的能力。而“听”作为直接交流的必备…     

县域“高中化学名师发展基地项目”的探索与实践

为落实《国家中长期教育改革和发展规划纲要》,提升教师专业素养,肥城市教体局与北京师范大学化学学院签订“高中化学名师发展基地项目”,围绕高中教师特别关注的教材教法、课程衔接、科普教育、教研与论文写作、高考指导等主题,形成了“教学研训立体化”的高中化学教师培训体系,提升了高中化学教师的整体教育教学水平,培养出一批教学名师,催生出县域高中与优质高师教育共建教师研训共同体新样态。     

水溶液体系ΔfHmθ、ΔfGmθ及Smθ的研究

依据单质与化合物热力学标准的基本概念,提出水溶液体系的热力学"0"标准,给出ΔfHθm、ΔfGθm、Sθm定义,并通过水合离子的Sθm计算实例和误差分析,论证了单质、化合物与水合离子热力学数据可以通用。     

“亲水”材料未必“疏油”

材料的亲液性 (亲水或亲油 )是许多领域对材料特性考察的一个重要方面。如纤维的亲水性与纤维制品的服用性能有密切关系 ,亲水性纤维制成的内衣能增加穿着舒适感[1] ;又如 ,在膜分离的核心技术———反渗透 (ＲＯ)、超滤 (ＵＦ)和微滤 (ＭＦ)中 ,采用具有亲水性表面的膜能显著减少膜污染 ,延长膜的使用寿命[2 ] ;此外 ,填料床中的填料以及浮选过程中的矿粒等的亲液性都对相关过程影响重大。　　对于材料的亲液性 ,不少人有这样一种认识 ,即亲水的材料必定是疏油的 ,反之亦然。但仔细考察材料亲水亲油现象发生的本质 ,就会发现并非任何材料都…     

<Superscript>35</Superscript>Cl NQR for the SbCl<Subscript>3</Subscript> complex with aniline,SbCl<Subscript>3</Subscript>·NH<Subscript>2</Subscript>C<Subscript>6</Subscript>H<Subscript>5</Subscript>

The temperature dependence of the ³⁵Cl NQR frequencies and spin-lattice relaxation times has been investigated for a trigonal-bipyramidal vn complex SbCl₃·NH₂C₆H₅. Thermally activated motion of chlorine atoms (pseudorotation) was not revealed in the complex, in contrast to the vπ complexes of SbCl₃ with related molecular structures. The high potential barrier of pseudorotation in the aniline complex is likely to be due to the unusually high nonequivalence of Sb-Cl chemical bonds.     

Ternary Systems LiBr–LiVO<Subscript>3</Subscript>–Li<Subscript>2</Subscript>CrO<Subscript>4</Subscript> and KBr–KVO<Subscript>3</Subscript>–K<Subscript>2</Subscript>CrO<Subscript>4</Subscript>

The binary system KVO₃–K₂CrO₄ and two ternary systems, LiBr–LiVO₃–Li₂CrO₄ and KBr–KVO₃–K₂CrO₄, were studied. In the ternary systems, the compositions and melting points of eutectic alloys were determined by differential thermal analysis: (49.0 mol % LiBr, 5.0 mol % LiVO₃, 46.0 mol % Li₂CrO₄, 400°C) and (17.0 mol % KBr, 78.0 mol % KVO₃, 5.0 mol % K₂CrO₄, 458°C), respectively.     

Glass Formation in the Ternary System La<Subscript>2</Subscript>O<Subscript>3</Subscript>–As<Subscript>2</Subscript>S<Subscript>3</Subscript>–Er<Subscript>2</Subscript>O<Subscript>3</Subscript>

The boundaries of the glass formation region in the ternary system La₂O₃–As₂S₃–Er₂O₃ were found. Transparent glass of composition (La₂O₃)_0.03(As₂S₃)0.90(Er₂O₃)0.07 was studied by X-ray photoelectron and Raman spectroscopy. The intensities of the bands characterizing As–S, La–O, and Er–O bonds increased, and these bands were shifted toward higher energies. This was due to an increase in the covalence of these bonds and probably due to the formation of new bonds in the glasses. Samples in the glass formation region are resistant at 300 K to air, water, and organic solvents.     

Interactions in the Sn<Subscript>2</Subscript>Sb<Subscript>6</Subscript>S<Subscript>11</Subscript>–PbSnSb<Subscript>4</Subscript>S<Subscript>8</Subscript> system

The Sn₂Sb₆S₁₁–PbSnSb₄S₈ system was studied by physicochemical analysis methods (differential thermal, X-ray powder diffraction, and microstructural analyses and microhardness and density measurements). It was found that this system is a quasi-binary section of the SnS–PbS–Sb₂S₃ ternary system of the eutectic type. The coordinates of the eutectic are 42 mol % PbSnSb₄S₈ and 600 K. In the studied system, regions of solid solutions were detected, which extend for solid solutions based on Sn₂Sb₆S₁₁ to 4 mol % PbSnSb₄S₈ (α) and for solid solutions based on PbSnSb₄S₈ to 6 mol % Sn₂Sb₆S₁₁ (β).     

Crystal structure of glycine phosphite C<Subscript>2</Subscript>H<Subscript>5</Subscript>NO<Subscript>2</Subscript>·H<Subscript>3</Subscript>PO<Subscript>3</Subscript>

Single crystal X-ray diffraction study of glycine phosphite C₂H₅NO₂·H₃PO₃ was performed (monoclinic, space group P2₁/c, a = 7.401(3) Å, b = 8.465(3) Å, c = 9.737(3) Å; β = 100.73(5)°, Z = 4). It has been found that one of hydrogen atoms is located at the centre of symmetry forming two strong hydrogen bonds to yield H₄P₂O ₆ ^?2 dimers, while another hydrogen atom is statistically disordered over two positions and organizes the dimers into an infinite corrugated chain. The ordering of this hydrogen atom position and/or displacement of the other one from the centre of symmetry will lead to the loss of symmetry centre and lowering of the point group symmetry from C_2h to piezo-active group C₂ or C _s .     

CsBr—Cs<Subscript>2</Subscript>ZnBr<Subscript>4</Subscript>—Cs<Subscript>2</Subscript>CdBr<Subscript>4</Subscript>—Cs<Subscript>2</Subscript>HgBr<Subscript>4</Subscript> Four-component system

Component interactions in the CsBr—Cs₂ZnBr₄—Cs₂CdBr₄—Cs₂HgBr₄ system were studied using differential thermal analysis (DTA) and powder X-ra y diffraction. The system is characterized by a continuous solid solution series. New compounds have not been found.     

Reciprocal system 3Tl<Subscript>2</Subscript>S + Sb<Subscript>2</Subscript>Se<Subscript>3</Subscript> ⇆ 3Tl<Subscript>2</Subscript>Se + Sb<Subscript>2</Subscript>S<Subscript>3</Subscript>

Phase equilibria in the reciprocal system 3Tl₂S + Sb₂Se₃ ? 3Tl₂Se + Sb₂S₃ are investigated by DTA, X-ray powder diffraction, and emf measurements. Some polythermal sections, the isothermal section of the phase diagram at 400K, and the liquidus-surface projection for this system are constructed. The types and coordinates of invariant and univariant equilibria are determined. It is shown that the system is non-diagonal. Broad regions of solid solutions are found on the basis of the binary compounds Tl₂S and Tl₂Se and along the boundary system Sb₂S₃-Sb₂Se₃ and the sections Tl₃SbS₃-Tl₃SbSe₃, TlSbS₂-TlSbSe₂, and TlSb₃S₅-TlSb₃Se₅ of the phase diagram.     

New continuous solid solution in the Zn<Subscript>2</Subscript>InV<Subscript>3</Subscript>O<Subscript>11</Subscript>–Mg<Subscript>2</Subscript>InV<Subscript>3</Subscript>O<Subscript>11</Subscript> system

In this study, mechanical activation process was used for intimate mixing as well as producing finely ground particles, increased surface area and improved chemical reactivity of milled materials for producing SrTiO₃ from commercially pure strontium carbonate and TiO₂ as a contributive process. Characterization of milled powder mixture by X-ray diffraction analysis showed that disappearing, decreasing and/or shifting of the patterns occurred with mechanical activation that means amorphization was taken place. Amorphization was also demonstrated by FT-IR analysis where shift of band centers as well as the decrement of transmittance related to CO₃ was observed. Advantage of amorphization was established with high-temperature XRD analysis which showed 1300 °C was not enough for non-activated mixture to form SrTiO₃, whereas structure only composed of SrTiO₃ at 1000 °C for activated ones. The reason for this phenomenon was investigated by DTA-TG analysis, and it was based on energy accumulation originated from mechanical activation that corresponds to peak temperature shifting to the lower temperatures and CO₂ liberation at mechanical activation step arising from local temperature rising at the vial during high-energy milling that was understood from peak temperature, and area decrement of endothermic peak corresponds to decomposition of SrCO₃.     

Zr<Subscript>5</Subscript>Ir<Subscript>2</Subscript>In<Subscript>4</Subscript> – A Superstructure of the Lu<Subscript>5</Subscript>Ni<Subscript>2</Subscript>In<Subscript>4</Subscript> Type

Summary. Zr₅Ir₂In₄ was synthesized by reaction of the elements in a glassy carbon crucible in a water-cooled sample chamber of an induction furnace. The sample was characterized by X-ray diffraction on both powder and single crystals. Zr₅Ir₂In₄ crystallizes with a pronounced Lu₅Ni₂In₄ type subcell, space group Pbam, a=1739.5(6), b=766.3(2), c=338.9(2) pm. Weak additional reflections force a doubling of the subcell c axis. The superstructure of Zr₅Ir₂In₄ is of a new type: Pnma, a=1739.5(6), b=677.8(2), c=766.3(2) pm, wR2=0.0529, 1592 F² values, and 60 variable parameters. The group-subgroup scheme for the klassengleiche symmetry reduction is presented. The formation of the superstructure is most likely due to a puckering effect (size of the iridium atoms). The crystal chemistry of Zr₅Ir₂In₄ is briefly discussed.     

“蒸馏酒”还是“发酵酒”——对《科学史导论》中“spirits” 和“distillation”的再思考

科学史奠基者乔治·萨顿在《科学史导论》第二卷的第一部分对我国宋代酿酒著作《北山酒经》予以了简要描述,出现了“spirits”“distillation”等字样;而《北山酒经》被众多学者认为其描述对象是发酵酒(黄酒)。本文从东西方蒸馏技术和相关著作的文本分析对《科学史导论》中提及的蒸馏技术和蒸馏酒存在的可能性提出了质疑。     

Transformations of CO<Subscript>2</Subscript> in Two-Phase Systems C<Subscript>8</Subscript>F<Subscript>18</Subscript>–H<Subscript>2</Subscript>O and C<Subscript>6</Subscript>F<Subscript>6</Subscript>–H<Subscript>2</Subscript>O

The transformation of carbon dioxide in aqueous emulsions of perfluorons in the presence of oxygen in the air results in the formation of a mixture of oxalic acid and a minor set of organic compounds C₄–C₈. The maximum CO₂ consumption occurs in the emulsion with the C₈F₁₈: H₂O vol/vol ratio of 1: 0.42 at pH 2.4; the H₂C₂O₄ yield is 11 mol %.     

From Cs<Subscript>2</Subscript>Mo<Subscript>6</Subscript>Cl<Subscript>14</Subscript> to Cs<Subscript>2</Subscript>Mo<Subscript>6</Subscript>Cl<Subscript>14</Subscript>·H<Subscript>2</Subscript>O and Vice Versa: Crystal Chemistry Investigations

We report here the synthesis, the crystal structure and the luminescent properties of the new cluster compounds Cs₂Mo₆Cl₁₄·H₂O and Cs₂Mo₆Br₁₄·H₂O. Single-crystal X-ray diffraction performed on Cs₂Mo₆Cl₁₄·H₂O indicates that the compound crystallizes in the monoclinic space group C2/c with refined cell parameters a = 19.578 Å, b = 15.151 Å, c = 9.347 Å, and β = 115.64°. The structure can be described from discrete \(\left[ {{\text{Mo}}_{ 6} {\text{Cl}}^{\text{i}}_{ 8} {\text{Cl}}^{\text{a}}_{ 6} } \right]^{ 2- }\) anionic cluster units arranged in a “A–A’–A–A’” pseudo prismatic stacking parallel to (b, c) plane with both Cs⁺ cations and water molecules located between the layers. Moreover, the centric character of the trigonal structure of Cs₂Mo₆Cl₁₄ was also studied by combination of single-crystal X-ray diffraction and both X-ray and neutron powder diffraction. The results suggest an important influence of the sample preparation on the symmetry of the crystal structure. The crystal structure relationship between the \(\left[ {{\text{Mo}}_{ 6} {\text{Cl}}^{\text{i}}_{ 8} {\text{Cl}}^{\text{a}}_{ 6} } \right]^{ 2- }\) anionic cluster unit arrangements in Cs₂Mo₆Cl₁₄ and Cs₂Mo₆Cl₁₄·H₂O is discussed. Finally, the characterization of the luminescent properties of Cs₂Mo₆X₁₄ and Cs₂Mo₆X₁₄·H₂O (X = Cl, Br) indicates that emission profile is comparable regardless existence of water molecule in the crystal structure.     

Na<Subscript>2</Subscript>MoO<Subscript>4</Subscript>-K<Subscript>2</Subscript>MoO<Subscript>4</Subscript>-H<Subscript>2</Subscript>O system at 25°C

Phase formation in the Na₂MoO₄-K₂MoO₄-H₂O system was studied at 25°C. Two incongruently saturating complex phases are formed in this system: Na₃K(MoO₄)₂ · 9H₂O and NaK₃(MoO₄)₂. The densities, refractive indices, and dynamic viscosities of saturated solutions of the system were determined; molar volume and ionic strength isotherms were calculated. A correlation relation was found between solubility and solution properties in the system. The indicated double salts were recovered and characterized using chemical analysis, powder X-ray diffraction, complex thermal analysis, and IR spectroscopy.     

Coordinatively Unsaturated Polynuclear Mixed-Valent Sn<Superscript>II</Superscript>–Sn<Superscript>IV</Superscript> and Cu<Superscript>II</Superscript>–Sn<Superscript>IV</Superscript> Oxo-Centered Carboxylates

The tetranuclear mixed-valent oxo-cluster [Sn^IISn^IVO(O₂CCF₃)₄]₂ (1) has been prepared by reacting SnCl₂ with AgO₂CCF₃ in a sealed ampoule at 90 °C. Alternatively, 1 was obtained by acidolysis of Ph₃SnSnPh₃ with trifluoroacetic acid in solution. The X-ray diffraction study of 1 revealed the presence of a Sn^IIOSn₂^IVOSn^II core comprised of the penta-coordinated divalent and six-coordinated tetravalent tin atoms. The ¹¹⁹Sn NMR studies confirmed the stability of the cluster in solution and the presence of two different oxidation states of tin. An acidolysis of Ph₃SnSnPh₃ in the presence of [Cu₂^II(O₂CCF₃)₄] followed by sublimation of the resulting product at 90 °C afforded the first trinuclear mixed metal Sn–Cu cluster [(C₆H₅)₂Sn₂^IVCu^IIO(O₂CCF₃)₆] (2). The X-ray diffraction analysis of 2 revealed the presence of two phenyl groups attached to the six-coordinated tin(IV) atoms and the tetragonal pyramidal environment of the copper(II) atom. Both complexes have been obtained free of exogenous ligands.