多重分形降趋波动分析法和移动平均法的分形谱算法对比分析

多重分形降趋波动分析法(MFDFA)和多重分形降趋移动平均法(MFDMA)是用来估算一维随机分形信号多重分形谱的两种算法, 已被拓展应用于二维和高维分形信号的分析. 本文简要介绍了MFDFA和MFDMA算法及其在一维时间序列中的应用. 首次系统地从算法模型、计算统计精度、样本量的敏感性、无标度区选取的敏感性、矩选择的敏感性和计算量这六个方面对两种算法进行了对比分析, 以典型多重分形信号BMC信号为例, 分析两种算法的适用性和优劣性. 为实际应用中, 针对具体信号如何选用MFDFA或MFDMA算法, 以及两种算法的参数设置提供了有价值的参考.     

新外推完全多重网格法北大核心

使用新外推公式和高阶插值算子,为相邻细层提供好的初值,对初值使用磨光算子磨光几次后,再调用V型多重网格法求得该层数值解,构造了基于四阶紧致差分格式的新外推完全多重网格法.数值实验表明,与对比算法相比,新算法迭代次数少、计算时间短、稳健性强.     

黄酮-6-羧酸类化合物的合成、表征和抑菌活性

通过查尔酮路线合成了6种黄酮-6-羧酸化合物,采用I2/DMSO为氧化剂通过微波辐射合成了其中3种黄酮羧酸.所有化合物的结构通过NMR,IR和元素分析方法进行了表征,并采用X射线单晶衍射法进一步测定了黄酮-6,4'-二羧酸的晶体结构.初步生物活性试验结果表明,6种化合物对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌均有一定的抑制作用.     

N6-烷基-2-烷氧基腺苷化合物的合成及抗血小板凝集活性

以鸟瞟呤核苷(1)为原料,经羟基保护得到2’,3’,5’-三-O-乙酰基鸟嘌呤核苷(2),2与三氯氧磷反应得到2-氨基-6-氯-9-(2’,3’,5’-三-O-乙酰基-β-D-呋喃核糖)嘌呤(3),3经重氮化、水解和O-烷基化得到2-烷氧基-6-氯-9-(2’,3’,5’-三-O-乙酰基-β-D-呋喃核糖)嘌呤(4a～...     

新的滇桂艾纳香寡糖BROS结构分析

以滇桂艾纳香枝叶为原料,经陶瓷膜、有机膜分离,醇沉、Sevag法除蛋白,DEAE-纤维素柱层析和SephadexG- 10,SephadexG-50凝胶柱色谱纯化得到的BROS;经HPGPC检测分析表明,BROS为均一寡糖,MALDI-TOF-MS测定分子量为1314.用IR,HPLC,甲基化分析,GC-MS,NMR (1H NMR,13C NMR,1H)HCOSY,HMQC和HMBC)等方法对BROS结构进行表征,结果表明,该寡糖由1个葡萄糖(α-D-Glcp)和7个果糖(β-D-Fru组成,残基间以→2)Fruf-(1→链接,分子末端链接为a-Glcp-(1→,→2)-β-D-Fruf推出BROS的结构式为:β-D-Fruf1-(2→1)-β-D-Fruf2-(2→1)-β-D-Fruf3-(2→ 1)-β-D-Fruf4-(2→1)-β -D-Fruf5-(2→1)-β-D-Fruf6-(2→ 1)-β-D-Fruf7-(2→ 1)-a-D-Glcp.     

氨基酸席夫碱的合成及性质研究

合成了5种氨基酸席夫碱Sal-Gly(甘氨酸席夫碱)、Sal-Glu(谷氨酸席夫碱)、Sal-Met(甲硫氨酸席夫碱)、Sal-Tyr(酪氨酸席夫碱)、Sal-Arg(精氨酸席夫碱)及其金属锌离子配合物共10种化合物.用元素分析、核磁共振、红外光谱、紫外-可见光谱等手段对其组成的结构进行表征.以Sal-Tyr-Zn为主体,咪唑(1),1-甲基-咪唑(2),2-乙基-4-甲基咪唑(3),吡唑(4),4-碘苯胺(5),DABCO(1,4-重氮双环[2,2,2]辛烷)(6),邻苯二胺(7)和1,2-环己二胺(8)为客体,进行配位相互作用研究.选取大肠杆菌作为抑菌菌种,研究了氨基酸席夫碱的抑菌能力.结果表明,氨基酸席夫碱配体及金属锌配合物对大肠杆菌均有抑菌活性,配体的抗菌活性随氨基酸残基的增大而减小.金属锌配合物的抑菌活性大于其所对应的氨基酸席夫碱配体的抑菌活性,活性最大的则为Sal-Arg-Zn.     

含脱氢松香骨架的1,8-萘酰亚胺衍生物的合成及其对阴离子的识别

以歧化松香胺为原料合成了6个新型含脱氢松香骨架的1,8-萘酰亚胺衍生物2a～2b和3a～3d,其结构用1H NMR,13C NMR,MS和元素分析进行了表征.对3a～3d进行了阴离子识别研究,并对其识别机理进行了讨论.     

Syntheses and Characterization of Two Diiron Dithiolate Complexes Containing 4-Dimethylaminopyridine

Two diiron dithiolate complexes, (μ-pdt)Fe2(CO)5(C7H10N2) 3 and (μ-edt)-Fe2(CO)5(C7H10N2) 4 (pdt = -S(CH2)3S-, edt = -S(CH2)2S-), have been synthesized and characterized by single-crystal X-ray diffraction. Complex 3 crystallizes in the monoclinic system, space group P21/c with a = 10.168(4), b = 11.816(4), c = 16.595(7)  and β = 95.195(6)o; and complex 4 crystallizes in the orthorhombic system, space group P212121 with a = 9.317(3), b = 11.898(4), c = 34.006(10)  .The distances of Fe(1)–Fe(2) are 2.5058(9)  in 3 and 2.4942(10)  in 4, falling in the normal range of Fe–Fe bond length (2.49～2.57 ). The cyclic voltammograms show that 3 and 4 display irreversible reduction peaks (FeIFeI/ FeIFe0) at –1.717 V and –1.673 V vs. Ag/AgCl, respectively. With different acids, complex 3 has distinguishable behavior, two protonations in addition of HBF4-Et2O and single protonation besides HOAc-CH3CN, and complex 4 has a similar action to 3 with HOAc-CH3CN for a semblable structure.     

Synthesis and Characterization of a Homochrial Manganese（Ⅱ）Complex Constructed from （1R,2R）-（-）-Diaminocyclohexane-N,N biscarboxyl-salicylidene）

A homochrial manganese(Ⅱ) complex derived from chiral salen ligand (1R,2R)-(-)diaminocyclohexane-N,N-biscarboxyl-salicylidene) (1) has been synthesized through solvothermal procedure and characterized by IR,elemental analysis,TGA,circular dichroism (CD),powder and single-crystal X-ray crystallography.It crystallizes in monoclinic,space group C2 with a=32.987(7),b=7.4662(15),c=17.931(4),β=97.82(3)°,V=4375.0(15) 3,Z=8,D c=1.544 g/cm 3,F(000)=2096,M r=508.36,μ=0.658 mm-1,the final GOOF=0.975,R=0.0676 and wR=0.2068 for 6357 observed reflections with I > 2σ(Ⅰ).The coordination polymer 1 possesses a 1D infinite zigzag chain architecture constructed by the dicarboxyl-functionalized metallosalen ligand (MnSalen),and the polymeric chains are further assembled into a 2D supramolecular network structure via strong intermolecular hydrogen bonding interactions between the adjacent zigzag chains.     

Synthesis,Characterization and X-ray Crystal Structure of N,N＇-Bis（4-nitrophenylcarba-mothioyl）-isophthalamide·DMF

A new crystal of N,N'-bis(4-nitrophenylcarbamothioyl)isophthalamide DMF solva-te has been prepared at room temperature and characterized by elemental analysis and IR,MS,1H NMR spectra and X-ray single-crystal determination.The complex crystallizes in monoclinic,space group P21/c with a = 11.2093(12),b = 22.081(2),c = 13.9640(15) ,β= 112.128(2)°,V = 3201.8(6) 3,C28H30N8O8S2,Mr = 670.72,Dc = 1.391 Mg/m3,Z = 4,μ= 0.228 mm-1,F(000) = 1400,the final R = 0.0483 and wR = 0.1411(I > 2σ(I)).The molecular packing in the crystal is the result of N-H…O hydrogen bonding.