数形结合思想在二次函数问题中的应用

正一、借助二次函数图像,解决二次方程根的分布问题二次方程的根其实质就是其相应二次函数的图像与x轴交点的横坐标.因此,可以借助于二次函数及其图像,利用数形结     

AutoCAD的功能扩展及实现

文章论述了在ＡｕｔｏＣＡＤ中添加两项新功能的实用性，并给出了实现这两项功能的部分源程序。     

《啊，拓荒者!》中人物形象的生态女性主义分析

《啊，拓荒者!》，女主人公由于受到父权制世界观和人类中心主义的影响，缺乏对女性身份及自然的正确认知，因而性格中曾经存在着男权倾向：排斥女性身份并以征服和利用土地来满足自我利益。但随着其认知的深入，主人公逐渐接受自我身份，并产生了对人类与自然相互依存关系的深层认知。     

Synthesis and Crystal Structure of a New Two-dimensional Manganese Coordination Polymer： [Mn（L）（1,4-bdc）]

A new coordination polymer,[Mn(L)(1,4-bdc)] (L=11-fluoro-dipyrido[3,2-a:2,3-c]phenazine,1,4-bdc=benzene-1,4-dicarboxylate),has been synthesized through the hydrothermal method and characterized by elemental analysis,IR and single-crystal X-ray diffraction.It crystalli-zes in triclinic,space group P1 with a=9.7544(9),b=10.8254(10),c=11.5288(10),α=114.1300(10),β=96.6110(10),γ=105.0390(10)°,V=1038.62(16)3,Z=2,C 26 H 13 FMnN 4 O 4,M r=519.34,D c=1.661 g/cm 3,F(000)=526,μ(MoKa)=0.691 mm-1,R=0.0405 and wR=0.0977.The 1,4-bdc dianions link the neighboring Mn(II) atoms to yield a two-dimensional layer structure.The L ligands are attached on both sides of the layer.The π-π interactions between the L ligands of neighboring layers result in a three-dimensional supramolecular architecture.     

Synthesis,Crystal Structure and Characterization of a New Coordination Polymer Based on Trinuclear Mn（Ⅱ） Cluster：[Mn3（L）2（adip）3]·2H2O

The coordination polymer,[Mn3(L) 2(adip) 3]·2H2O(L = 2-(4-fluorophenyl) -1H-imidazo[4,5-f] [1,10]phenanthroline and H2adip = adipic acid) ,has been synthesized under hydro-thermal conditions and characterized by elemental analysis,IR and single-crystal X-ray diffraction. It crystallizes in triclinic,space group P1 with a = 8.4085(11) ,b = 11.1273(14) ,c = 14.5758(18) ,α = 78.528(2) ,β = 75.425(2) ,γ = 78.143(2) °,V = 1276.0(3) 3,Z = 1,C56H50F2Mn3N8O14,Mr = 1261.86,Dc = 1.642 g/cm3,F(000) = 647,μ(MoKa) = 0.819 mm-1,R = 0.0446 and wR = 0.1008. The backbones of the two types of adip dianions link the neighboring trinuclear Mn(Ⅱ) clusters to yield a two-dimensional layer structure. The large conjugated L ligands are located on both sides of the two-dimensional layers. Additionally,the O-H···O,O-H···N and N-H···O hydrogen bonds further stabilize the structure.