A New Three—dimensional Network Constructed by Heptamolybdate,SodiumIons and Hexamethylene Tetramine Cations via Hydrogen Bonds

1 INTRODUCTION The role played by CH…O hydrogen bonds in determining molecular conformation and crystal packing, in molecular recognition processes, in the stabilization of inclusion complexes, and possibly in the activity of biological macromolecules has been well established[1,2]. According to Desirajus structural setting for C-H贩稯 hydrogen bonds, the D (to define the C贩稯 contact distances) values within the range of 3.00~4.00 and the angles of CH…O with 150≤≤180 are stru…     

Synthesis, Structural Characterization and Reactivity of Two New Triangular Molybdenum Cluster Compounds: Mo_3Te_7-[S_2CN(CH_2CH_2OH)_2]_3I and Mo_3Te_4Y_3[S_2P( ~iPrO)_2]_3I (Y_3=1.43Te+1.57S)

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由氨基酸配位的铜修饰十二核钨单元构成的一维链状化合物(H3O)3{[Na3(H2O)13][(Cu(Gly)2)2(H2W12O42)]}·11H2O

The design and synthesis of organic-inorganichybrid compounds have aroused contemporary inter-est;not only owing to their diverse structures,but alsoto their potential applications in fields such as catal-ysis,medicine,analytical chemistry and photochem-i…     

A Novel Two-dimensional Layer Compound Built up by Hexapolyoxotungstates and Coordinated Sodium Chains

1 INTRODUCTION There has been extensive interest in the synthesis of heteroxometallates owing to their fascinating pro- perties and great potential applications in many fields, such as catalysis, material science, medicine and magnetochemistry as well as their unusual topo- logical properties[1～4]. Although various preparation methods have been proposed for the preparation of such materials, to find new synthetic method for novel compounds in this field is still one of the major chal- le…     

回归正交设计分光光度法测定克感敏片各组分含量

本文提出了克感敏片中氨基比林、非那西丁、咖啡因和扑尔敏四组分回归正交设计分光光度法同时测定的新方法，比ＡＫＣ法和ＣＰＡ法更简便、快速、准确。     

Syntheses and Structural Characterizations of a Series of Capped Keggin Derivatives

Hydrothermal reactions of Na2 Mo O2·2H2O and NH4VO3(or V2O5) with appropriate reducing agents such as organic amines, NH2OH·HCl and Mo(CO)6 gave rise to the formation of a series of capped Keggin derivatives, [N(CH3)4]2Na3(NH4)2[(VVO4)MoVI8VIV4O36(VIVO)2]·-13H2O(1), [NH4]7[(VVO4)MoVI8VIV4O36(VIVO)2]·7H2O(2), [HN(CH2CH2)3NH][(PO4)MoV3MoVI9O36(VIVO)2]·-3[N(CH2CH2)3N]·(en)·4.5H2O(3) and [HNH2OH][NH4]2[(VVO4)MoVI8VIV4O36(VIVO)4]·24H2O(4). Single-crystal X-ray diffraction analysis revealed that the anions in 1~3 are two-capped Keggin derivatives with characteristic trans vanadium-oxygen caps, whereas the heteropoly anion in 4 is a tetra-capped α-Keggin derivative with characteristic vanadium-oxygen caps on the equatorial plane.     

激光诱导氮气等离子体时间分辨光谱研究及温度和电子密度测量

激光诱导击穿光谱(LIBS)作为一种重要的分析手段被广泛应用于材料分析、环境监测等领域.特别是随着大气污染问题的日趋严重,基于LIBS的大气污染在线监测分析技术快速发展,氮气等离子体特性的时间演化规律对研究激光诱导大气等离子体动力学和发展大气污染监测的LIBS技术具有重要意义.而温度和电子数密度作为表征等离子体状态最重要的参数,直接影响着等离子体形成、膨胀和退化中的动力学过程以及等离子体中的能量传输效率.本文利用等离子体时间分辨光谱,研究了连续背景辐射、分子谱线强度及信背比(分子谱线与连续背景辐射的比值)在等离子体演化过程中的变化规律,结果显示连续背景辐射寿命在700 ns左右,N_2~+(B~2Σ_u~+-X~2Σ_g~+,v:0-0)跃迁谱线强度在12—15μs范围内达到最大值,信背比随时间呈现上升、稳定的趋势,因此利用N+2分子离子第一负带系(B~2Σ_u~+-X~2Σ_g~+)研究等离子体温度的观测窗口应选择在10—25μs之间;基于双原子光谱理论,通过拟合实测光谱和仿真光谱研究了大气压下激光诱导氮气等离子体温度随时间的演化趋势,由于辐射损耗远小于碰撞作用,在10—28μs内等离子体温度从约10000 K按指数衰减到约6000 K;在准确测定仪器展宽线型的基础上,利用Nelder-Mead单纯形算法,研究了N原子746.831 nm谱线的Stark展宽和位移随时间的演化趋势,计算了等离子体中电子数密度随时间在10~(17)—10~(16)cm~(-3)量级间衰减,通过分析发现造成等离子体中电子数衰减的主要机理是三体碰撞复合.     

有意义学习理论对中学化学教学的启示

奥苏贝尔有意义学习理论系统阐述了发现学习与接受学习、有意义学习与机械学习的区别与联系。本文从当前中学化学教学中存在的偏颇入手,介绍了有意义学习理论对中学化学教学的指导作用,提出了中学化学教学中实施先行组织者策略,运用同化模式条件,帮助学生完备认知结构的方法,对提高教学效率有一定的借鉴作用。     

CRDS-CARS-PLIF技术精确定量测量火焰OH浓度实验研究（英文）

在预混甲烷/空气燃烧的平面火焰炉上，采用脉冲式光腔衰荡光谱技术(cavity ring-down spectroscopy, CRDS)实现了对OH分子浓度的定量测量。根据光腔衰荡吸收光谱理论，选取OH的A₂Σ⁺-X₂Π(0,0)电子跃迁带中的P₁(2)吸收谱线构搭建了一套激光波长在308.6 nm的脉冲CRDS实验装置。脉冲CRDS装置中的衰荡光腔是由一对反射率为99.7%的高反射镜组成且其衰荡腔的腔长为270 cm,并测量空腔(光腔中无火焰)的衰荡时间为2.33μs。通过理论分析影响浓度精确测量的实验参数，分别采用平面激光诱导荧光(planar laser induced fluorescence, PLIF)、相干反斯托克斯拉曼散射(coherent anti-stokes Raman scattering, CARS)和脉冲CRDS三种技术精确测量OH的有效吸收长度、高温火焰的温度和有效的光腔衰荡时间。当在平面火焰炉上燃烧预混的甲烷(1.1 L·min^-1)和空气(15...