ZnSe纳米片晶的可控合成

以乙二胺四乙酸(EDTA)为稳定剂、丁胺(BA)为结构导向模板, 采用水热合成方法制备了尺寸和晶型可控的ZnSe纳米片晶; 利用XRD, TEM, SEM以及紫外-可见漫反射等手段对所得的产物进了表征, 结果表明, 通过改变水热温度和BA用量, 可以实现ZnSe纳米片晶的大小和物相的调控, 并初步分析了其形成过程.     

HG-AAS测定废水中微量As(Ⅲ)和As(Ⅴ)

在自然界水体中砷主要以无机的As(Ⅲ)和As(Ⅴ)的形态存在,而As(Ⅲ)的毒性比As(Ⅴ)大得多[1],因此必须对As(Ⅲ)和As(Ⅴ)分别测定才能可靠评价砷的毒性及其生物重要性[2-4]。目前砷的化学形态分析方法很多,萃取法、巯基棉富集分离法、离子交换法[5]等可实现砷的形态分析,但操作复     

基于同步辐射原位CT的水牛角结构性能关系研究

为探究水牛角的结构性能关系,基于上海同步辐射光源搭建了高分辨原位CT系统,对水牛角角鞘进行初始表征和准静态压缩下的实时表征,并通过Top-Hat方法提取了角鞘内孔洞三维形貌.结果显示,水牛角角鞘孔隙率在1％左右,椭圆柱状孔洞沿牛角生长方向排列成线,首尾相连却并未连通,均匀分布在波浪状片层之间.孔洞特征椭球的轴长分布满足...     

Theoretical Study on Enol-keto Tautomerism of α-Fluorine-β-diketones

Density Functional Theory method is applied to investigate the enol-keto tautome- rism of both acyclic and cyclic α-fluorine-β-diketones. It is shown that, for acyclic cases, α-fluorine could improve the relative stability of keto tautomer by lessening intramolecular hydrogen bond of enol form, whereas the relative stability of cyclic enol could be attributed to two factors: destabi- lization of keto and stabilization of enol. Furthermore, the relative stabilities of all enol tautomers are improved in THF to different extents.     

Synthesis and Crystal Structure of 4,4′-(4-(1-Naphthyl)-4-phenyl- 1,3-butadienylidene)-bis[N,N-diethylbenzenamine]

The title compound (C40H42N2) has been synthesized by the reaction of 1-(1-naphthyl)-1-phenyl-3-chloropropylene and bis(4-(diethylamino) phenyl)methanone, and characterized by IR, 1H NMR, MS and X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 17.047(3), b = 10.807(2), c = 1&494(4) (A), β = 105.727(4)°, V=3279.4(11) A3, Mr = 550.76, Z = 4, Dc = 1.115 g/cm3, μ(MoKα) = 0.085 mm-1, F(000) = 1184, the final R = 0.0625 and wR = 0.1384 for 2276 observed reflections (I ＞ 2σ(Ⅰ)). X-ray analysis reveals that the butadiene fragment adopts a planar cisiod conformation and makes a dihedral angel of 69.4(2)° with the naphthalene ring.     

Synthesis, Spectroscopic Properties and Crystal Structural Characterization of a Triphenyltin(Ⅳ) Complex with 5-Bromonicotinic Acid

A novel organotin complex [Ph3Sn(C2H5OH)(OCOC5H3NBr)SnPh3(OCOC5H3NBr)]has been synthesized by the reaction of 5-bromonicotinic acid with triphenyltin hydroxide in ethanol and characterized by elemental analysis, IR and 1H NMR. The crystal structure was determined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 15.564(2), b = 24.975(4), c = 12.2973(19) (A), β = 92.224(2)°, Z = 4, V = 4776.5(13) (A)3, Dc = 1.596g/cm3, μ(MoKα) = 2.765 mm-1, F(000) = 2264, R = 0.0385 and wR = 0.0667. In the molecular structure of the title complex, the tin atoms are five-coordinated in a trigonal bipyramidal geometry.     

Lamb波频域逆散射全聚焦成像方法研究

Lamb波因其传播距离远、衰减小常被用于板状结构的无损检测中,在基于Lamb波损伤检测的诸多成像技术中,全聚焦方法(Total Focus Method,TFM)方法因其成像分辨率高、信噪比高而受青睐.然而Lamb波的频散效应导致时域延时量不能被准确计算,进而影响传统TFM方法对损伤定位及成像的精度;此外,既有的TFM...     

Synthesis and Crystal Structure of a New Mononuclear Nickel(Ⅱ) Mixed Complex Derived from 2-Aminoethyl-bi(3-bi-aminopropyl)amine with 1,10-Phenanthroline

The mixed complex [Ni(L)(L')](ClO4)2 has been synthesized using 2-aminoethyl- bi(3-bi-aminopropyl)amine with phen (1,10-phenanthroline) in the presence of Ni(II) ion, and its structure was determined by X-ray diffraction. The crystal crystallizes in monoclinic, space group P21/c with a = 13.713(2), b = 13.1466(19), c = 14.780(2) (A), β = 97.620(3)°, V = 2640.9(7)(A)3, F(000) = 1272, Z = 4, Dc = 1.540 g/cm3, R = 0.0536 and wR = 0.1207. The Ni2+ ion is six- coordinated to furnish a distorted octahedral geometry.     

完全三部图K(n-k,n,n)的色唯一性

通过对图的特征子图个数的比较,给出了图K(n-k,n,n)色唯一性的数值条件.     

MATLAB曲面绘制中的挖补方法

在MATLAB绘图中,将函数数据的某一部分换成内置变量NaN(或Inf),或者将函数数据中的NaN换成适当的实数,可分别实现绘图中的挖、补方法.并且给出一些具体的应用实例.