On Vertex-Edge-Degree Topological Descriptors for Certain Crystal Networks

Due to the combinatorial nature of graphs they are used easily in pure sciences and social sciences.The dynamical arrangement of vertices and their associated edges make them flexible(like liquid)to attain the shape of any physical structure or phenomenon easily.In the field of ICT they are used to reflect distributed component and communication among them.Mathematical chemistry is another interesting domain of applied mathematics that endeavors to display the structure of compounds that are formed in result of chemical reactions.This area attracts the researchers due to its applications in theoretical and organic chemistry.It also inspires the mathematicians due to involvement of mathematical structures.Regular or irregular bonding ability of molecules and their formation of chemical compounds can be analyzed using atomic valences(vertex degrees).Pictorial representation of these compounds helps in identifying their properties by computing different graph invariants that is really considered as an application of graph theory.This paper reflects the work on topological indices such as ev-degree Zagreb index,the first ve-degree Zagrebindex,the first ve-degree Zagrebindex,the second ve-degree Zagreb index,ve-degree Randic index,the ev-degree Randic index,the ve-degree atom-bond connectivity index,the ve-degree geometric-arithmetic index,the ve-degree harmonic index and the ve-degree sum-connectivity index for crystal structural networks namely,bismuth tri-iodide and lead chloride.In this article we have determine the exact values of ve-degree and ev-degree based topological descriptors for crystal networks.

Synthesis and Crystal Structure of Zinc(II) Complex with Isonicotinate Containing a Three-dimensional Hydrogen-bond Network

A zinc complex, [Zn(iso)_2(H_2O)_4](iso=C_6H_4NO_2^-), was synthesized and characterized by elemental analysis, thermal analysis and IR spectrum studies. The crystal structure of the complex was determined by X-ray diffraction. The crystal crystallizes in the triclinic system, molecular formula ZnC12H16N2O8, Mr=381.64, space group P with a = 6.338(1), b =6.919(1), c=9.277(1), α=96.28(1), β=104.91(1), γ=112.85(1)°, V=352.12(9)?3, Z=1, Dc=1.80g?cm-3 and F(000)=196, μ =1.791mm-1. The crystal structure was solved by direct methods for final R=0.0204 and Rw=0.0542 for 1258 observed reflections with [Fo>4σ(Fo)]. The crystal structure reveals that zinc ion is trans-octahedral with two pyridyl nitrogens and two aque oxygens at the equational positions and two aqua oxygens at the axial positions. The complex forms a three-dimensional network through intermolecular hydrogen bonds.

SYNTHESIS AND CRYSTAL STRUCTURE OF THE FIRST THREE DIMENSIONAL NETWORK CU(Ⅱ) COMPLEX BRIDGED BY BOTH OXAMIDE AND AZIDE

A novel three dimensional network complex polymer [Cu_4(oxen)_2(N_3)_3]_n(ClO_4)_n·2nH_2O, where oxen is N,N' -bis(2-aminoethyl)oxamide dianion, has been synthesized. It crystallizes in triclinic system, space group P, with a=11.486(2), b=11.706(3), c=12.291(3) , α=77.42(2), β=67.59(2), γ=77.96(2)°, and z=2. The least-square refinements converged at R=0.047, with 3416 observed unique reflections. The complex has a pronounced three-dimensional character and can be viewed as the tetranuclear asymmetric repeating units through inversion and translation operations to extend a three-dimensional network. The structure of Cu_4 asymmetric unit consists of two square planar and two square pyramidal Cu central atoms linked by both azide ligands in end-on and end-to-end bonding modes, and oxamidate bridge in trans conformation.

Wideband Reconfigurable Millimeter-Wave Linear Array Antenna Using Liquid Crystal for 5G Networks

The advanced design of a 10 × 1 linear antenna array system with the capa-bility of frequency tunability using GT3-23001 liquid crystal (LC) is pro-posed. The design for this reconfigurable wideband antenna array for 5G ap-plications at Ka-band millimeter-wave (mmw) consists of a double layer of stacked patch antenna with aperture coupled feeding. The bias voltage over LC varies from 0 V to 10.6 V to achieve a frequency tunability of 1.18 GHz. The array operates from 25.3 GHz to 33.8 GHz with a peak gain of 19.2 dB and a beamwidth of 5.2° at 30 GHz. The proposed reconfigurable antenna ar-ray represents a real and efficient solution for the recent and future mmw 5G networks. The proposed antenna is suitable for 5G base stations in stadiums, malls and convention centers. It is proper for satellite communications and radars at mmw.

氧化石墨烯/液晶网络复合膜的响应性能及仿生设计

液晶网络是由液晶聚合物单体适度交联得到,兼具有聚合物的弹性和液晶的各向异性,包括多刺激响应能力、可逆的驱动以及可编程的形状变形等性能,因此具有良好的外场响应性、分子协同作用和弹性。氧化石墨烯膜层具有优秀的光热转换性能,而光具有环保性、远程可控性等优异的特性,因此光致形变的氧化石墨烯/液晶网络(GO-LCNs)复合膜逐渐成为人们的研究热点。它可以制作柔性机器人、仿生光热驱动器等先进器件,具有良好的发展前景。本文在两种厚度的液晶网络膜上制作氧化石墨烯薄膜,构成氧化石墨烯/液晶网络复合膜,测量了温度或红外光作用下液晶网络膜厚度对其响应性能的影响。本文结果为复合膜的应用设计提供了实验基础,并以此为基础设计了GO-LCNs复合膜的仿生器件。

不同拉伸方式引起BOPP薄膜的结构特征与绝缘介电性能

采用不同拉伸方式以及改变双向拉伸聚丙烯(BOPP)薄膜厚度,调节伸直链晶含量(厚晶片)、纤维化形貌和取向形态,并考察这些结构因素对介电性能的作用规律。结果表明,热稳定的伸直链晶和纤维网络的结构各向同性有利于提高击穿场强、降低介电损耗;对电介质薄膜加工-结构-性能关系的深入理解能够为设计、开发高品质电容膜产品提供参考。

图卷积神经网络在晶体材料研发中的应用进展

【目的】探讨图卷积神经网络模型在晶体材料研究中的应用及未来可能的发展方向。【方法】首先介绍图卷积神经网络的发展历程及研究现状,然后对目前图卷积神经网络在晶体材料中的应用进行分类探讨,最后展望未来图卷积神经网络在晶体材料领域中的研究方向。【结果】图卷积神经网络在自然科学研究中得到越发广泛的应用,在晶体材料的结构设计和性能预测中展现出较好的效果。【结论】图卷积神经网络已逐渐应用于晶体材料的设计和预测,提高模型的泛化性以及如何提取深层特征,是图卷积神经网络未来的研究方向。

Influence of Annealing and Additives on the Crystallization Behavior and Properties of Poly(vinyl chloride)

Acetanilide （AC）, adipic acid （AA） and potassium hydrogen phthalate （PHP） were chosen as additives to accelerate PVC crystallization and improve its mechanical properties. The influences of the additives and annealing on the crystallization behavior, micromorphology and the tensile properties were investigated by the thermal analysis, scanning electron microscopy （SEM） and the tensile test. Based on the analysis results, it was concluded that the melting peaks ranging from 110 to 200 ℃ and 200 to 240 ℃ were caused by the fusion of the fringed micelle crystals and chain-folded crystals respectively. AC advanced the fringed micelle crystal to develop, while AA and PHP promoted obviously the chain-folded crystal to grow. The addition of the foreign additives did not change the growth pattern ofPVC crystallites, the growth of the micelle crystal was favorable at 110 ℃, and the chain-folded crystal was developed at higher temperature. For PVC/ AA and PVC/PHP, when annealed at 110 ℃, a regular nest like network was formed, the crystallinity and the crystallite size were increased as well, and as a result, the tensile strength, Young＇s modulus and the elongation at break point were improved simultaneously and greatly.

Supramolecular Network Obtained from the Interaction of Dihydrophosphate Anions and Thiourea-based Receptors

Two crystals of receptor 1, C（42）H（52）N（10）O4S2（anthracene-9,10-dicarbaldehyde bis-（phenyl-semithiocarbazone）） and-1-H2PO4, C（68）H（114）N（10）O（10）P2S2 were obtained at room temperature successfully, and their structures were characterized by X-ray crystallography diffraction. X-ray diffraction reveals that, receptor 1 crystallizes in monoclinic, space group P21/c, with a = 9.487（3）,b = 20.674（6）, c = 11.821（4）A, β = 113.416（8）o, Mr = 825.06, V = 2127.5（12） A^3, Z = 2, Dc = 1.288g/cm^3, μ = 0.18 mm^-1, F（000） = 876, MoK α radiation（λ = 0.71073 A）, the final R = 0.0472 and wR = 0.0930. A total of 3758 unique reflections were collected, of which 3313 with I 〉 2σ（I） were observed. Compound 1-H2PO4^-crystallizes in triclinic, space group P21/n, with a = 8.767（1）, b =13.6190（15）, c = 16.615（2） ？, α = 98.727（14）, β = 103.061（14）, γ = 91.382（16）°, Mr = 1357.75, V =1906.6（4） A^3, Z = 1, Dc = 1.183 g/cm^3, μ = 0.17 mm-（-1）, F（000） = 734, MoK α radiation（λ = 0.71073？）, the final R = 0.0769 and wR = 0.1884. A total of 6699 unique reflections were collected, of which 2989 with I 〉 2σ（I） were observed. As it was observed in the crystal structure of 1-H2PO4^-, 1bound H2PO4^-at a 1：2 ratio by intermolecular interaction of N-H···O hydrogen bond obviously.Another interesting feature was that H2PO4--groups assembled chains themselves via intramolecular hydrogen bond O-H···O and connected the 1 molecules together through the interaction of H-bonds,which improved the planarity of 1 and increased the stability of the entire structure.

基于GRU神经网络的恒温晶振频率漂移预测

恒温晶振作为新时代5G通信系统的重要器件,其频率稳定性相当重要,准确预测恒温晶振频率漂移可以提高系统工作状态的安全性与可靠性。为进一步提高频率漂移预测精度,满足5G通信系统需求,提出了一种基于门控循环单元(GRU)神经网络的晶振频率预测模型。该模型同时考虑温度、老化两种因素,并利用神经网络具有出色的自适应性与非线性泛化能力,学习恒温晶振频率漂移变化规律。最后以14 d实测数据为例进行研究分析,并与循环神经网络、长短时记忆神经网络做对比实验,以均方根误差、平均绝对误差、算法运行时间作为评价指标,结果表明GRU网络具有更高的预测精度、更快的运算速度。

基于Crystal Ball的PERT网络计划项目工期风险分析

文章介绍了网络计划技术,对PERT网络计划项目各活动持续时间的确定进行了分析,总结了使用Crystal Ball进行风险分析的步骤,构建了某PERT网络计划项目各活动的时间参数的Excel模型。在此基础上,使用Crystal Ball建立该项目的工期风险分析模型,并对该模型进行风险分析,获得有效的分析结果。

Hydrothermal Synthesis and Crystal Structure of Manganese(Ⅱ) Coordination Polymer Assembled by 4-Sulfophthalate and 4,4′-Bipyridine

The rational design and synthesis of metal-directed supramolecular framework compounds have received much attention in coordination chemistry because of their potential applications in catalysis, molecular selection, nonlinear optics, ion exchange, and microelectronics. Many high-dimensional coordination complexes have been designed and prepared through molecular self-assembly processes. The open metal organic framework can be produced via two kinds of interactions, i. e. , coordinate covalent bonds and weaker intermolecular forces. For this reason, the most efficient means to synthesize these compounds is to establish possible connections among different units.

Synthesis and Crystal Structure of a Novel Three-dimensional Manganese(Ⅱ) Coordination Polymer:[Mn(pdc)]_n (pdc=Pyridine-2,4-dicarboxylate)

A novel manganese（H） coordination polymer [Mn（pdc）]n （pdc = pyridine-2,4- dicarboxylate） has been synthesized under hydrothermal conditions. The crystal is of monoclinic, space group P211n with a = 6.506（4）, b = 9.392（6）, c = 11.217（7） A, β = 105.650（12）°, V= 660.0（7）A3, Z = 4, Mr = 220.04, Dc = 2.215 g/cm3,μ = 1.971 mm-1, F（000） = 436, Rint = 0.0345, R = 0.0360 and wR = 0.0778 for 1259 observed reflections with I 〉 2σ（I）. In the structure, the Mn（Ⅱ） atom is coordinated in a distorted octahedral arrangement by one pyridine N and five carboxylate O atoms from five pdc ligands, each of which coordinates to five Mn atoms to propagate a three-dimensional layered framework.

Synthesis and Crystal Structure of [{Cd(hmbdc)(H_2O)_3}·2H_2O]_n

A novel coordination polymer [{Cd（hmbdc）（H20）3}-2H20],, （hmbdc = 5-hydroxyisophthalic acid） has been synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P2Jc, with a = 9.599（3）, b = 18.699（5）, c = 7.557（2） A, r= 108.198（4）°, V= 1288.6（6） A3, Z= 4, M,.= 382.60, Dc = 1.972 g/cm^, F（000） = 760, p = 1.740, the final R =0.0555 and wR = 0.0995 for 1732 observed reflections with 1 〉 2σ（I）. The structural analysis shows that the intermolecular hydrogen bonds and π-π interactions result in a three-dimensional supramolecular framework.

Solvothermal Synthesis,Crystal Structure and Characterizations of a Novel 2D Organic Decorated Manganese Thiostannate:MnSnS3(1,2-DACH)

A novel 1,2-diaminocyclohexane（1,2-DACH） decorated manganese thiostannate,namely MnSnS_3（1,2-DACH）（1）,has been solvothermally synthesized by the reaction of Mn（CH_3COO）_2·4H_2O,Sn and S in the stoichiometric ratio in 1,2-DACH,which acted as an efficient structure-directing agent（SDA） and reactive solvent in the formation of the title compound. Single-crystal X-ray diffraction studies revealed that the title compound crystallizes in the monoclinic space group P2_1/c with a = 12.2458（7）,b = 13.8588（7）,c = 7.2292（4） ？,β = 99.460（6）°,V = 1210.20（12） ？~3,Z = 4,Dc = 2.108 g·cm^（-3）,F（000） = 748,μ = 3.584 mm^（-1）,R = 0.0348 and wR = 0.0823（I 〉 2σ（I））. The structure features a neutral two-dimensional（2D） network constructed by the unsaturated [Mn（1,2-DACH）] complexes interconnecting [SnS_3]_n^（2n-） chains via sharing S. Thermal stability and optical property of compound 1 were characterized.

ClO_4^--directed Assembly of Two Co^ⅡComplexes Based on Flexible N-donor Ligands:Syntheses,Crystal Structures and Magnetic Properties

The reaction of Co^II ions with 1,4-bis（imidazol）butane（bimb） or 1,4-bis（triazol）butane（bitb） in the presence of ClO4^-, respectively affords two CoII coordination complexes, namely {[Co（bimb）3]·2ClO4}n（I） and {[Co（bitb）3]·2ClO4}n（II）. Single-crystal X-ray analysis indicates that both complexes I and II show the same α-Po topological structures. However, complex I exhibits a 2-fold interpenetrating network, while complex II features a 3-fold interpenetrating network. In addition, solid-state properties such as thermal stabilities and magnetic properties of two complexes were also investigated.

Construction and the Second-order Nonlinear Optics of a New Chiral Coordination Network Based on Two Types of Homo-chiral Helices

A new 2D chiral cadmium coordination network [Cd（TCBA）2]？2EtOH （1） was prepared by the reaction of achiral angular asymmetric bridging ligand 2-（（3,5-dimethyl- 4H-1,2,4-triazol-4-yl）-carbamoyl）-benzoic acid （TCBA） with cadmium acetate, which was structurally characterized by IR, elemental analysis, thermogravimetric analysis and single-crystal X-ray diffraction. Complex 1 crystallizes in the chiral space group P21 and features a 2D chiral network consisting of two types of homo-chiral helices, which are further extended into a 3D chiral framework along the a-axis via hydrogen bonds. Moreover, powder second-order nonlinear optical （NLO） measurements reveal complex 1 has a modest second-harmonic-generation （SHG） efficiency at room temperature.

Synthesis and Crystal Structure of a New Supramolecular Compound Constructed from Flexible 1,1'-(1,4-Butanediyl)bis(imidazole) and 1,2,4,5-Benzenetetracarboxylic Acid

A new bis（imidazolium） compound,[H2L（H2btec）2]·H4btec（1,L=1,1＇-（butane-1,4-diyl）bis（imidazole）,H4btec=1,2,4,5-benzenetetracarboxylatic acid）,has been synthesized and structurally characterized by single-crystal X-ray diffraction.The title compound crystallizes in the monoclinic system,space group Pnma,with a=13.3908（11）,b=13.9249（12）,c=16.2166（14）,V=2957.6（4）3,Z=4,Mr=698.55,Dc=1.569 mg/m3,F（000）=1448,μ（MoKα）=0.130 mm-1,the final R=0.0584 and wR=0.1538 for 4295 observed reflections with I2σ（I）.The compound consists of one 1,1＇-（butane-1,4-diyl）bis（imidazolium） cation,one neutral H4btec and one H2btec2-（Only two para carboxyl groups are deprotonated,and two protonated ones remain free） anion.A one-dimensional hydrogen bonding chain and a 2D hydrogen bonding network are formed via intermolecular N–H…O and O–H…O hydrogen bonds.These adjacent chains are further stacked through intermolecular π-π and hydrogen bonding interactions to form a 3D supramolecular network.

Syntheses,Characterization,and Crystal Structures of Three New Divalent Metal Sulfonates

Reactions of M（Ⅱ） acetate （M = Cu, Ni） with disodium 4,4＇-biphenyldisulfonate （BPDS） and 2,2＇-bipyridine （2,2＇-bipy） yielded three new metal sulfonates formulated as {[Cu2（2,2＇-bipy）2（H2O）（C2O4）（BPDS）]·2H2O}n 1, [Cu（2,2＇-Bipy）（H2O）3]（BPDS）＇2H2O 2 and [Ni（2,2＇-Bipy）（H2O）4]（BPDS）·2.5H2O 3. These three compounds were characterized by elemental analyses, FT-IR spectra, TG-DTA analyses and single-crystal X-ray diffraction analyses. Compound 1 belongs to the monoclinic system, space group P21/c with a = 17.7942（2）, b = 10.1369（10）, c = 19.8681（3） A, β = 104.323（10）°, V = 3472.20（7）A3, Mr = 893.82, Z = 4, F（000） = 1824,μ（CuKa） = 3.295 mm-1, R = 0.0427 and wR = 0.1278. Compound 2 is of orthorhombic system, space group Pca21 with a = 20.1016（7）, b = 7.2460（2）, c = 17.4802（6）A, V= 2546.10（14）A3, Mr = 622.11, Z= 4, F（000） = 1284,μ （CuKα） = 3.314 mm-1, R = 0.0415 and wR = 0.1291. Compound 3 belongs to the monoclinic system, space group C2/c with a = 15.9204（5）, b = 11.7511（4）, c = 15.2559（4）A, β = 98.886（3）°, V = 2819.85（15）A3, Mr = 1288.60, Z = 2, F（000） = 1340,μ（CuKa） = 2.957 mm^-1, R = 0.0515 and wR = 0.1454. Compound 1 is composed of one-dimensional helical chains of [Cu2（2,2＇-bipy）2（H2O）（C2O4）]2＋ fragments bridged alternately by 4,4＇-biphenyldisulfonate ligands, along the c axis of the unit cell. In compound 2, 4,4＇-biphenyldisulfonate anions are arranged in a zigzag mode and interact with the lattice waters via hydrogen bonds resulting in the formation of infinite chains. Adjacent chains are linked by lattice waters to form 2D extended sheets. The complex cations are located in the interlayer regions and interact with the sheets through hydrogen bonds. In compound 3, the Ni center resides at a crystallographic inversion center and adopts a distorted octahedral coordination sphere. The complex cations interact with 4,4＇-biphenyldisulfonate anions via O-H…O hydrogen bonds, creating 2D extended grid structures. The lattice waters are located in the interlayer regions.

Synthesis and Crystal Structure of a Three-dimensional (3D) Complex Mn(H_2O)_2(HNic)_2 (HNic=2-Hydroxynicotinic Acid)

The title complex Mn（H2O）2（HNic）2 （C22H12MnN2O8, Mr = 367.18） crystallizes in monoclinic, space group P21/c with a = 7.5735（8）, b = 12.5295（13）, c = 7.6466（8）A.β = 101.2790（10）°, Z = 2, V= 711.59（13） A^3, D, = 1.714 g/cm^3,μ（MoKa） = 0.974 mm^-1, F（000） = 374, R1 （1255 observed reflections （Ⅰ 〉 2σ（Ⅰ）） = 0.0250） and wR2 = 0.0662 （all data）. In this paper, we report the complexation of Mn（Ⅱ） by the bidentate ligand 2-hydroxynicotinic acid （HNic）. In the crystal the Mn（Ⅱ） ion exhibits a deformed octahedron structure. The title complex Mn（H2O）2（HNic）2 has a three-dimensional （3D） network structure extended by hydrogen bonds, which are formed by two typical eight-membered hydrogen-bonded rings.