Synthesis and Characterization of a Novel Organic-Inorganic Hybrid Compound [Ni（DMF）6]3[PMo （12）O （40）]2

Inthelastfewyears,therehasbeenextensive researchinpolyoxometalates(POMs)fortheirstruc turaldiversityandpotentialapplicationinthefieldsof catalysis,biology,medicineandmaterialscience[1,2].POMs,whichareexcellentmolecularacceptors,can formnovelinorganic organiccomplexeswithanum beroforganicsubstratescontainingN,S,Oatoms.Inordertoimprovethephysicochemicalpropertiesof theorganic POMshybridmaterials,metalionscanbe introducedtothesystem.Organoamineisusually usedastemplateorstructure directingagen…     

SO2-4 , HCO-3侵蚀作用下水泥砂浆的抗压强度

工程结构中的水泥砂浆在使用过程中经常会受到侵蚀性离子的作用，致使水泥砂浆性能劣化强度降低.为了改善结构的耐久性，通过模拟试验，分别探讨了SO^2-₄ 、HCO^-3这两种侵蚀性离子在不同浓度不同龄期下对水泥砂浆的单轴抗压强度和应力应变关系的影响.试验结果表明，SO^2-₄、HCO^-3对水泥砂 浆的侵蚀性均比较明显，其中一定浓度的SO^2-₄对水泥砂浆的强度具有一定的增强作用.该研究对水泥砂浆在复杂环境中的应用有重要的参考价值.     

Al2O3/(W, Ti)C纳米复合陶瓷材料的力学性能与强韧化机理

采用纳米和亚微米级的α-Al₂O₃,以及微米级的(W,Ti)C粉体为原料,制备了Al₂O₃/(W,Ti)C纳米复合陶瓷材料.在基体Al₂O₃含有体积分数为11%的纳米Al₂O₃时复合材料的抗弯强度和断裂韧性达到最优,其抗弯强度、断裂韧性和硬度分别为840MPa,6.55MPa·m^1/2和20.1GPa.TEM实验表明,纳米颗粒的加入明显抑止了基体晶粒的长大,形成了典型的骨架结构,材料的断裂方式为沿晶断裂和穿晶断裂的混合.内晶型和晶间型第二相颗粒产生的残余应力场、断裂模式的改变和晶粒细化强化促进了复合材料抗弯强度和断裂韧性的提高.     

Synthesis,Characterization and Formation Mechanism of Friedel’s Salt（FS:3CaO·A12O3·CaCl2·10H2O） by the Reaction of Calcium Chloride with Sodium Aluminate

The synthesis of Friedel’s salt(FS: 3Ca O·A12O3·Ca Cl2·10H2O) by the reaction of calcium chloride with sodium aluminate was investigated. Factors affecting the preparation of Friedel’s salt, such as reaction temperature, initial concentration, titration speed, aging time and molar Ca/Al ratio were studied in detail. XRD, SEM images and particle size distribution show that the reaction temperature, aging time and molar Ca/Al ratio have significant effect on the composition, crystal morphology, and average particle size of the obtained samples. In addition, the initial Ca Cl2 concentration and Na Al O2 titration speed do not significantly influence the morphology and particle size distribution of Friedel’s salt. With the optimization of the operating conditions, the crystals can grow up to a average size of about 28 um, showing flat hexagonal(or pseudohexagonal) crystal morphology. Moreover, two potential mechanisms of Friedel’s salt formation including adsorption mechanism and anion-exchange mechanism were discussed. In the adsorption mechanism, Friedel’s salt forms due to the adsorption of the bulk Cl- ions present in the solution into the interlayers of the principal layers, [Ca2Al(OH-)6·2H2O]+, in order to balance the charge. In the anion-exchange mechanism, the free-chloride ions bind with the AFm(a family of hydrated compounds found in cement) hydrates to form Friedel’s salt by anion-exchange with the ions present in the interlayers of the principal layer, [Ca2Al(OH-)6· 2H2O]+-OH-.     

A study of the effect of Sudan Ⅰ, Ⅲ, and Ⅳ on the DNA/RNA ratio and 3D structure of HepG-2 using LCM

To explore the effect of sudan Ⅰ, Ⅲ, and Ⅳ on the DNA/RNA ratio and changes in the 3D structure of HepG-2. LCM and 3D images are used to detect the DNA/RNA ratio and changes in the 3D structure of HepG-2 when treated with different dosages of sudan Ⅰ, Ⅲ, and Ⅳ. The DNA/RNA ratio of the control group is 1. 223 2 ± 0. 084 4, while the fluorescence intensity of DNA in HepG-2 treated with sudan Ⅰ, Ⅲ, or Ⅳ is markedly greater than that of RNA, with the low-dosage group showing significant effect (P ＜ 0.01 ), yielding DNA/RNA ratios of 1. 609 6 ±0. 199 0, 1. 445 5 ±0. 163 3, 1. 708 1 ±0. 109 0 respectively; 3D images show that DNA fluorescence in HepG-2 is mostly concentrated in the nuclear region, and is denser and stronger than RNA fluorescence. The DNA/RNA ratio of a treated group increases after being treated with different dosages of sudan, but it declines with increasing dosage, and within a certain dosage range, sudan Ⅰ, Ⅲ, and Ⅳ are shown to promote the growth of HepG-2.     

A study of the effect of Sudan Ⅰ, Ⅲ, and Ⅳ on the DNA/RNA ratio and 3D structure of HepG-2 using LCM

To explore the effect of sudan Ⅰ, Ⅲ, and Ⅳ on the DNA/RNA ratio and changes in the 3D structure of HepG-2. LCM and 3D images are used to detect the DNA/RNA ratio and changes in the 3D structure of HepG-2 when treated with different dosages of sudan Ⅰ, Ⅲ, and Ⅳ. The DNA/RNA ratio of the control group is 1. 223 2 ± 0. 084 4, while the fluorescence intensity of DNA in HepG-2 treated with sudan Ⅰ, Ⅲ, or Ⅳ is markedly greater than that of RNA, with the low-dosage group showing significant effect (P ＜ 0.01 ), yielding DNA/RNA ratios of 1. 609 6 ±0. 199 0, 1. 445 5 ±0. 163 3, 1. 708 1 ±0. 109 0 respectively; 3D images show that DNA fluorescence in HepG-2 is mostly concentrated in the nuclear region, and is denser and stronger than RNA fluorescence. The DNA/RNA ratio of a treated group increases after being treated with different dosages of sudan, but it declines with increasing dosage, and within a certain dosage range, sudan Ⅰ, Ⅲ, and Ⅳ are shown to promote the growth of HepG-2.     

A study of the effect of Sudan I, III, and IV on the DNA/RNA ratio and 3D structure of HepG-2 using LCM

Sudans are artificially synthesized red colorants.As industrial colorants,they are widely used for hyper-chromatic effect for solvents,oils,waxes,and petrole-um,and as polish for shoes and floor boards.Sudans are lipophilic azo-compounds,and includemainly sudan I,II,III,and IV.In chemical nomen-clature,sudan I is1-phenylazo-2-naphthalenol,orC6H5=NC10H6OHin structural formula,with a molec-ular weight of248·28,and sudan II,III,and IV are1-[(2,4-dimethylphenyl)azo]-2-naphthalenol,1-{[4-…     

The Corrosion Behavior of Ni-Y Binary Alloys in Air and in Molten （0.62Li,0.38K）2CO3 Mixture at 650℃

The corrosion behavior of pure Ni and of binary Ni-Y alloys containing 1wt%,3wt%,5wt% Y,respectively,was investigated in air and in the eutectic (0.62Li,0.38K)2CO3 mixture at 650 ℃.The alloys are two-phase composed of γ-Ni solid solution and intermetallic compound Ni17Y2.The experimental results indicated that the corrosion of Ni-Y alloys in air and in molten salts,respectively,produced an external NiO scale with a small amount of Y2O3 and an internal oxidation region composed of Ni and Y2O3 resulting from the oxidation of the intermetallic phase Ni17Y2.The presence of yttrium in the alloy had a positive effect on the lithiation reaction of NiO during immersion in the melt.     

立方图的邻域同调分类

立方图是指每个顶点的次数都等于３的有限简单连通图，本文讨论了立方图的邻域复形的性质，证明了两个立方图是邻域同调的充要条件为它们的二分性相同并且Ｄ值相等。     

边色临界图的1-因子和几乎1-因子的存在性

根据Vizing邻接引理和关于临界图和二分图的3个结论,利用图的1-因子和几乎1-因子存在的充要条件,采用结构图论的方法证明了:1)若G是2n阶临界图,且δ(G)≥n-3,则G存在1-因子;2)若G是2n+1阶临界图,且δ(G)≥n-4,则G存在几乎1-因子.     

边色临界图的1-因子和几乎1-因子的存在性

根据Vizing邻接引理和关于临界图的独立数的一个结论,利用图的1-因子和几乎1-因子存在的充要条件,采用结构图论的方法证明了：1）若G是2n阶△～临界图,且△≥n,δ≥n-2,则G存在1-因子;2）若G是2n＋1阶△-临界图,且△≥n＋1,δ≥n-2,则G存在几乎卜因子．     

关于平面图的3-选色

图G的选色数记为ch(G),定义为最小的自然数K,使得满足:对于任意顶点给定的K种颜色列表,染色时每个顶点的颜色只能从自身的颜色列表中选择时,图G的顶点总存在一个正常着色。我们证明了每个围长至少为4且不含5-,8-和11-圈的平面图是3-可选色的,以及每个围长至少为4且不含6-,9-和10-圈的平面图是3-可选色的。     

关于图的海明优美性

给出了海明优美图的一个必要性定理,证明了海明优美图Ｇ的任意个点上接任意棵树所得的图也是海明优美图,海明优美图Ｇ（Ｇ≠Ｋ２）与任意棵树的并图是海明优美图。     

关于扇图的优美性

图的标号问题在编码设计等方面的应用越来越受到关注。求出一个特殊图类的所有优美编号是一种新的尝试。对扇图Fn的优美性进行了研究,给出了详尽的证明过程,通过建立的数学模型和计算机算法求得了扇图的所有优美标号。     

图集上随机游动的覆盖时

研究了有限图上的简单随机游动对它的顶点至少访问一次所需的期望时间,得到了完全图的期望上界为Ｏ（ｎｌｏｇｎ）,（其中ｎ为相应图的顶点数）对对称图,也给出了它的覆盖时的上、下界以上结论改进了原有的结果,是有关图集上随机游动的覆盖时研究有意义的新的成果     

导出子图中不含K4-e的无爪立方图的完美匹配个数

设G是一个简单图,具有顶点集合V（G）和边集合E（G）。若图G的任意导出子图都不与K1,3同构,则称G是一个无爪图。一个立方图是一个所有顶点都是三度点的图。本文给出了一类特殊图--不含K4-e的无爪立方图的完美匹配计数。 更多还原     

关于无6-,7-和8-圈的平面图的3-可选择性

G的列表着色是指V(G)的一个颜色安排使得每个点从给定的列表L(v)中得到一个颜色并且使相邻的点染不同的颜色.L(G)=(L(v)v∈V(G))称为G的颜色列表.如果G满足一个列表着色,且每个列表中包含k种颜色,则称G是k-可选择的.本文证明了围长为4的无6-,7-和8-圈的平面图是3-可选择的.     

图的2-下交[O,k_j]_1~m-因子分解

在[0,k1 … km-m 1]-图的正交[0,kj]1m-因子分解问题的基础上,讨论了[0,k1 … km-m 1]-图的2-正交[0,kj]1m-因子分解问题,并给出了该问题的一个充分条件.