Synthesis and Crystal Structure of[Na(DB24C8)]_2(WMo_5O_(19))

Complex C_(48)H_(64)Mo_5Na_2O_(36) W, M_r=1910.55, monoclinic, space group P2_1/c, a=10. 906(4), b=14. 230(5) , c=20. 519(5) A, β=92. 77(2)°, V=3180. 7(8) A￣3, Z=2 , D_c=1. 995 g/cm3, F(000) = 1876 . μ=28. 78 cm￣(-1), the final R=0. 050 and R_ω=0. 055 for 2863 observed unit reflections I≥3σ(I), The supermolecule consists of one [WMo_5O_(19)]2-anion that has a crystallographic inversion centre and two DB24C8 complexes of Na+ cation which is located in the cavity by electrostatic interaction.

Synthesis and Crystal Structure of ［Na（DB18C6）（CH_3OH）］_2Mo_6O_（19）·（DB18C6）·（CH_3OH）

The preparation method of [Na ( DB18C6) (CH_3OH )]_2Mo_6O_(19)·(DB18C6)·(CH_3OH) , where DB18C6 is dibenzo-18-crown-6, is described. Thecrystal and molecular structure of the title complex has been determined crystallographically. The title complex crystallizes in the monoclinic system,space group P2_1/c ,a=18. 727(6) ,b=19. 555(6) , c=22. 827(7) ,β=112. 84(3)°, V=7704(4) ￣3 ,M_r = 2102. 9 , Z = 4 , F (000 ) = 4224 , μ= 1 . 028 mm ￣(-1), D_c = 1.813 g/cm￣3 . final R =0. 075 and R_w= 0. 078 based on 4463 observed reflections with F>6. 0σ(F) . The complex consists of [Mo_6O_(19)]￣(2-) ,[Na(DB18C6)]￣+ and CH_3OH, which are linked by long distance interaction through O-Na-O bond.

Synthesis and Crystal Structure of Co(C_6NO_2H_4)_3. H_2O

The reaction of CoCl2. 6H2O with picolinic acid gives the title compound Co-(C6NO3H4)3. H2O at room temperature. The crystallographic data for Co(C6NO3H5)3. H2O: monoclinic, space group C2/c, a= 29. 8316(6), b= 8. 573(2),c= 13. 835(3) , β= 95. 93(3)°, Z= 16, Mr=443. 3, Dc= 1. 673 g/cm3, μ(MoKa)= 1. 109 mm-1, F (000) = 1808, R =0. 036, R. =0.048 for 2497 independent observed reflections [F≥4.0σ(F)]. The Co atom is coordinated by three oxygen andthree nitrogen atoms, forming a distorted octahedral coordination geometry. In the unitcell, two kinds of isomerides are included. They are the mirror images to each other.

基于DEM的双线隧道地表沉降规律

为研究隧道开挖引起的地表沉降规律,运用PFC2D软件模拟Trapdoor试验,通过沉陷门下沉对双线隧道开挖引起的地表沉降规律及影响因素进行了系统研究。基于休止角试验和单Trapdoor模型试验得到数值模型的计算参数,通过开展单Trapdoor数值试验获取地表沉降曲线,拟合得到单线隧道开挖引起的地面沉降Peck公式参数。开展同时开挖的双Trapdoor数值试验,利用单Trapdoor参数叠加得到双线隧道开挖引起的地表沉降预测公式,并与简单叠加公式的拟合结果进行对比。最后进行先后开挖的双Trapdoor数值试验,揭示了隧道间距、埋深和双线隧道开挖顺序对地表沉降的影响规律。结果表明:随着隧道埋深的增加和隧道间距的减小,地表沉降曲线由"W"形态向"V"形态过渡;先后开挖工况下双线隧道引起的地表沉降曲线呈非对称分布,地表沉降量最大值出现在先行隧道一侧,且随着隧道埋深的增加,地表沉降曲线两侧最大值的差异有增加趋势;Peck公式拟合结果与离散单元法(DEM)数值模型和模型试验结果吻合较好,可用于双线隧道开挖引起的地表沉降预测,具有重要的理论指导和工程意义。