Effects of Phenyl Content and Molecular Structure on the Refractive Index of Organic Silicon Polymer

The effects of phenyl content and group distribution on the refractive index of phenyl silicone oil were investigated by synthesis and characterization of silicone oils of different molecular structures.A group contribution function model was established to predict the refractive index. The results showed that refractive index of phenyl silicone oil increased as its phenyl content increased. A linear equation had been established to describe the quantitative relationship between the refractive index and phenyl content.Refractive index values from the group contribution function model showed good consistency with experimental results.

ELECTRONEGATIVITY TOPOLOGICAL INDEX AND ITS APPLICATION IN CORRELATION WITH MX,MX_2,MX_3,MX_4 MOLECULAR PROPERTIES

A New electronegativity topological index is defined and used to correlate with properties of MX,MX_2,MX_3,MX_4.

Coverless Information Hiding Based on the Molecular Structure Images of Material

The traditional information hiding methods embed the secret information by modifying the carrier,which will inevitably leave traces of modification on the carrier.In this way,it is hard to resist the detection of steganalysis algorithm.To address this problem,the concept of coverless information hiding was proposed.Coverless information hiding can effectively resist steganalysis algorithm,since it uses unmodified natural stego-carriers to represent and convey confidential information.However,the state-of-the-arts method has a low hidden capacity,which makes it less appealing.Because the pixel values of different regions of the molecular structure images of material(MSIM)are usually different,this paper proposes a novel coverless information hiding method based on MSIM,which utilizes the average value of sub-image’s pixels to represent the secret information,according to the mapping between pixel value intervals and secret information.In addition,we employ a pseudo-random label sequence that is used to determine the position of sub-images to improve the security of the method.And the histogram of the Bag of words model(BOW)is used to determine the number of subimages in the image that convey secret information.Moreover,to improve the retrieval efficiency,we built a multi-level inverted index structure.Furthermore,the proposed method can also be used for other natural images.Compared with the state-of-the-arts,experimental results and analysis manifest that our method has better performance in anti-steganalysis,security and capacity.

Vertex degree autocorrelation topological index and its application in QSAR study of organic chemicals

Considering the calculated result and higher degeneracy existing in the calculation of autocorrelation topological index totally depend on experimental parameters, a new group of autocorrelation topological index as A t, B t, C t and D t was designed and developed based on the vertex degree of molecular topology and autocorrelation function of mathematics. Autocorrelation function f(i) was calculated from the square root of the vertex degree, revised vertex degree and their combination, and they are (δ i) 1/2 , (δ V i) 1/2 ,(δ V i+δ i) 1/2  and (δ E i-δ i) 1/2 / N. With the matrix description method achieved, and the unit input in matrix of unsaturated bond and heteroatoms revised based on the adjacency matrix and distance matrix of organic molecular graph, the corresponding computer software has also been designed and developed. Better results have been obtained for the application of these indexes in QSAR study of organic chemicals.

Prediction of the Physical Properties for the Ionic Liquid Based on Topological Index

Based on the distance matrix and adjacent matrix of molecular structure, a novel topological index is proposed. A set of topological parameters is built to reflect the magnitude, shape and other structure information of the substance. The interdependency between new topological index and conductivity for alkylimidazolium cations was analyzed and a quantitative relationship to describe this interdependency was obtained using the linear analyzing method. The analysis results show that the proposed topological index is quite satisfied with higher precision of the prediction. From the molecular structure of ionic liquid, the value of conductivity can be predicted correctly. This method can be also used to predict other physical properties of the ionic liquid.

Structure-controlled slow dynamics in Al−Mg melts

Molecular dynamics simulation was employed to investigate the dynamical and structural properties of Al−Mg melts with the Al concentration systematically changed.The results show that the viscosity of Al67Mg33 abnormally surpasses that of Al85Mg15 below 550 K,inconsistent with the tendency at high temperatures.The evolution of the icosahedral order population is found to account for this dynamic behavior.Structural analysis shows a preferred bonding between Al and Mg atoms in the nearest neighbor shells,while a repelling tendency between them in the second shells,leading to the prepeak emergence in the partial static structure factors.The formation of icosahedral clusters is constrained in the Al-rich compositions because of the lack of sufficient Mg atoms to stabilize the clusters geometrically.These results demonstrate the structural consequence through the interplay between geometric packing and chemical interaction.These findings are crucial to understanding the structure−dynamic properties in Al−Mg melts.

Schultz Polynomials and Their Topological Indices of Jahangir Graphs J2,m

Let G = (V;E) be a simple connected graph. The Wiener index is the sum of distances between all pairs of vertices of a connected graph. The Schultz topological index is equal to and the Modified Schultz topological index is . In this paper, the Schultz, Modified Schultz polynomials and their topological indices of Jahangir graphs J2,m for all integer number m ≥ 3 are calculated.

The First Eccentric Zagreb Index of Linear Polycene Parallelogram of Benzenoid

Let G = (V,E) be a graph, where V(G) is a non-empty set of vertices and E(G) is a set of edges, e = uv∈E(G), d(u) is degree of vertex u. Then the first Zagreb polynomial and the first Zagreb index Zg1(G,x) and Zg1(G) of the graph G are defined as Σuv∈E(G)x(du+dv) and Σe=uv∈E(G)(du+dv) respectively. Recently Ghorbani and Hosseinzadeh introduced the first Eccentric Zagreb index as Zg1*=Σuv∈E(G)(ecc(v)+ecc(u)), that ecc(u) is the largest distance between u and any other vertex v of G. In this paper, we compute this new index (the first Eccentric Zagreb index or third Zagreb index) of an infinite family of linear Polycene parallelogram of benzenoid.

Different effects of economic and structural performance indexes on model construction of structural topology optimization

The objective and constraint functions related to structural optimization designs are classified into economic and performance indexes in this paper.The influences of their different roles in model construction of structural topology optimization are also discussed.Furthermore,two structural topology optimization models,optimizing a performance index under the limitation of an economic index,represented by the minimum compliance with a volume constraint（MCVC）model,and optimizing an economic index under the limitation of a performance index,represented by the minimum weight with a displacement constraint（MWDC）model,are presented.Based on a comparison of numerical example results,the conclusions can be summarized as follows：（1）under the same external loading and displacement performance conditions,the results of the MWDC model are almost equal to those of the MCVC model;（2）the MWDC model overcomes the difficulties and shortcomings of the MCVC model;this makes the MWDC model more feasible in model construction;（3）constructing a model of minimizing an economic index under the limitations of performance indexes is better at meeting the needs of practical engineering problems and completely satisfies safety and economic requirements in mechanical engineering,which have remained unchanged since the early days of mechanical engineering.

Some Topological Indices Computing Results If Archimedean Lattices L(4,6,12)

The introduction of graph-theoretical structure descriptors represents an important step forward in the research of predictive models in chemistry and falls within the lines of the increasing use of mathematical and computational methods in contemporary chemistry.The basis for these models is the study of the quantitative structure-property and structure-activity relationship.In this paper,we investigate Great rhom-bitrihexagonal which is a kind of dodecagon honeycomb net-work covered by quadrangle and hexagon.Many topological indexes of Great rhom-bitrihexagonal have being investigated,such as sum-connectivity index,atom-bond connectivity index,geometric-arithmetic index,fifth,harmonic index,Randićconnectivity index,first Zagreb index,second Zagreb index and the corresponding Zagreb polynomials,modified Zagreb index,fourth atom-bond connectivity index,augmented Zagreb index,hyper-Zagreb index,Sankruti index,forgotten topological index,first multiple Zagreb index,second multiple Zagreb index,as well as derived geometric-arithmetic index,Narumi-Katayama index and modified Narumi-Katayama index.

一种有机杂化硅膜分子模型的重构研究

BTESA有机杂化硅膜具有复杂的无定形结构,广泛应用于气体分离、有机溶剂处理和能源存储等领域,但目前仍缺乏成熟的分子级表征模型.本文结合分子动力学模拟和反应力场,在纳米尺度上构建BTESA有机杂化硅膜的分子模型,并采用X射线衍射、径向分布函数、孔径分布探究该分子模型的化学结构和孔隙拓扑.结果表明,采用分子模拟构建的BTESA样品的衍射图样与实验数据一致,准确地揭示了BTESA有机杂化硅膜的化学结构与孔隙拓扑.研究结果为BTESA有机杂化硅膜及其他有机杂化硅膜提供了一种成熟的纳米尺度模型构建方法和孔隙拓扑结构分析技术.

一种新型二级凸轮式分度机构动力学仿真

针对一种新型二级凸轮式分度机构的拓扑结构特点,在ADAMS软件环境下建立了机构动力学模型,分析机构的输出响应。在此基础上,研究了转速、惯性负载及针齿分度圆半径等因素对整机动态性能的影响规律。此外,分析了传动构件的针齿强度。结果表明:机构输出轴角速度值随着转速的提高而大幅度增加,随着针齿分度圆半径的增大而减小,其波动幅值随负载的增大而明显减小。机构分度期内针齿与凸轮间的动态啮合力显著波动,上述研究成果可为该类分度机构的工况参数选择原则提供一定的参考。

基于深度学习的多参数结构拓扑优化方法

基于有限元的拓扑优化方法,需要多次有限元求解与迭代,由此消耗了大量的计算资源与时间。为提高拓扑优化效率,本文以悬臂梁结构拓扑优化设计为例,引入过滤半径、体积分数、载荷作用点及加载方向4个优化参数,提出了一种基于残差连接的生成式卷积神经网络(CNN)模型,分析了样本数量及损失函数类型对生成式CNN模型精度的影响规律。结果表明:所建立的生成式CNN模型具有较高的精度与泛化能力,模型预测值与有限元仿真结果平均结构相似度可达0.9720,平均绝对误差为0.0143。该模型预测耗时仅为有限元法的0.0041倍,显著提升了结构拓扑优化效率。

植物精油成分气相色谱保留指数的全息定量构效关系

气相色谱保留指数(RI)是色谱分析中的重要参数,但通过实验获取RI值的过程较为繁琐,需要建立一种简便、高效、准确的模型来预测RI值。本文搜集了60种植物精油成分的RI实验值,构建了精油成分化合物的结构性质与RI值之间的全息定量构效关系(HQSAR)模型。当碎片大小(fragment size)、碎片特征(fragment distinction)和全息长度(hologram length)模型参数分别设置为“1~4”、“C,Ch”和199时,可以建立最优HQSAR模型。利用外部测试集验证和留一交叉验证对模型进行检验,经外部测试集验证的预测均方根误差(RMSEP)、预测决定系数(Q_(F3)^(2))、一致性相关系数(CCC)和平均相对误差(MRE)分别为40.45、0.984、0.968和2.20%;经留一交叉验证的交叉验证均方根误差(RMSECV)和MRE分别为72.56和4.17%。此外,HQSAR模型的分子贡献图表明,芳香族化合物的烷基链在连接了羟基基团后,其RI值会增大;脂肪族化合物中存在的长链烷基也会导致RI值增大。研究结果表明,所建立的HQSAR模型能够用于预测植物精油成分的RI值,并为其他精油成分RI值的预测提供可靠依据。

Stratification structures on a kind of completely distributive lattices and their applications in theory of topological molecular lattices

A completely distributive lattice is also called a molecular lattice.The least and the greatestelements in a lattice are denoted by 0 and 1,respectively.For the empty subset L of alattice L,we assume that V=0 and ∧=1.The set of all the molecules（i.e.non-zero∨-irreducible elements）in a lattice L is denoted by M（L）. Let L1 and L2 be completely distributive lattices,f:L1→L2 and g:L2→L1 be order-preserving maps.If for any a∈L1 and any b∈L2,f（a）≤b if and only if a≤g（b）,then fis called the left adjoint of g,or g is called the right adjoint of f.The right adjoint of f

分子结构和拓扑结构选择性调控PMA型添加剂的性能

黏度是润滑油分级与选用的重要指标,合适的黏度是充分润滑的保证。在众多的润滑油添加剂中,降凝剂和黏度指数改进剂被认为是调节油品黏度、确保油品具有出色低温流动性和卓越黏温性能的关键。甲基丙烯酸酯类聚合物(PMA)具有灵活的结构可调变性和较强的合成工艺适应性,在降凝剂和黏度指数改进剂领域占有重要的地位。基于此,综述了PMA添加剂在改善润滑油低温流动性和黏温性能方面的作用机理,重点讨论和总结了PMA分子结构和拓扑结构对其产品性能的影响机制,展望了PMA添加剂未来的发展方向。

加强胶质细胞瘤中分子网络的整体性研究

胶质母细胞瘤(Glioblastoma,GBM)是由多种遗传和表观遗传学改变而驱动的一类疾病,单个或少数几个分子靶点可能不足以治愈这类肿瘤.特别是当前的很多研究,虽然在实验研究中取得了较好的结果,但是在临床治疗中却难以获得明显的疗效.这充分说明,人体内真实的肿瘤环境,是多因素驱动的一类疾病,而针对单一或少数几个靶点,是难以逆转肿瘤的恶性程度的.在这类多因素之中,最主要的一个方面就是基因表达的多样性.根据目前的研究报导,GBM中存在大量异常表达的基因,在这些异常基因中,是否存在单个或少数的基因可作为治疗的靶点?对于这一问题目前仍是未解之谜.然而,一个普遍接受的事实是,众多的分子存在相互作用,这种作用形成了一个复杂的分子互作网络(molecular interacting network,MINW)系统.这个MINW的整体性质,将最终影响肿瘤的进展和转归.本文就这一现象,进行归纳性小结,以飨读者.

一个新的分子拓扑指数

通过将键参数和量子数引入原子点价,重新定义原子点价δYi,认为分子中某一原子的δYi与该原子的杨氏电负性力标、价电子数、成键电子数及最外层主量子数有关.由此提出新的分子拓扑指数mXY.并用一级指数1XY与饱和烷烃的沸点、液体热容、气体热容、蒸发热、临界温度、临界压力,卤代苯的辛醇/水分配系数,烷氧氯硅烷的气相色谱保留指数、含氮杂环化合物的毒性,碱金属卤化物的晶格焓与F心能带,卤化锡的119SnMossbauer等性质/活性进行相关关系的研究.结果表明,1XY与有机物和无机物的性质/活性间具有广泛良好的相关性.

表面活性剂HLB值的分析测定与计算 Ⅱ.HLB值的计算

介绍了根据表面活性剂的结构和结构参数等性质直接计算表面活性剂 HLB值的多种公式 。

单硫醚气相色谱保留指数拓扑化学研究

在分子拓扑化学理论的基础上,根据分子中原子的特性,用分子中原子的平衡电负性对分子图进行着色,在距离矩阵的基础上结合分子中各原子的支化度构建一组新的拓扑指数NPm(m=1,2,3),利用多元线性回归技术将单硫醚在4种极性固定相的气相色谱保留指数与NPm(m=1,2,3)建立相应的定量结构-保留相关关系模型(QSRR),并用这种模型对单硫醚的气相色谱保留指数进行预测,结果表明,预测结果和实验值吻合较好。