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。

Crystal structure graph neural networks for high-performance superconducting critical temperature prediction

The utilization of machine learning methods to predict the superconducting critical temperature(T_(c))traditionally necessitates manually constructing elemental features,which challenges both the provision of meaningful chemical insights and the accuracy of predictions.In this work,we introduced crystal structure graph neural networks to extract structure-based features for T_(c)prediction.Our results indicated that these structure-based models outperformed all previously reported models,achieving an impressive coefficient of determination(R^(2))of 0.962 and a root mean square error(RMSE)of 6.192 K.From the existing Inorganic Crystal Structure Database(ICSD),our model successfully identified 76 potential high-temperature superconducting compounds with T_(c)≥77 K.Among these,Tl_(5)Ba_(6)Ca_(6)Cu_(9)O_(29)and TlYBa_(2)Cu_(2)O_(7)exhibit remarkably high T_(c)values of 108.4 and 101.8 K,respectively.This work provides a perspective on the structure-property relationship for reliable T_(c)prediction.

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。

A machine learning-based crystal graph network and its application in development of functional materials

An active area of MGI(Materials Genome Initiative)/MGE(Materials Genome Engineering)is to accelerate the development of new materials by means of active learning and“digital trial-error”using a prediction model of material property.Machine learning methods have widely been employed for predicting crystalline materials properties with crystal graph neural networks(CGNN).The prediction accuracy of the state-of-the-art(SOTA)CGNN models based on big models and big data is generally higher.However,for the development of some classes of materials,the datasets obtained by experiments are usually lacking due to costly experiments and measurement costs.The lack of datasets will impact the accuracy of CGNN models and may result in overfitting during training models.This paper proposes a simplified crystal graph convolutional neural network(S-CGCNN)which possesses higher prediction accuracy while reducing the vast amount of train datasets and computation costs.The S-CGCNN model has successfully predicted properties of crystalline materials,such as piezoelectric materials and dielectric materials,and increased the prediction accuracy up to 12%-20%than existing SOTA CGNN models.Furthermore,the distribution map between properties and compositions of materials has been built to screen the latent space of candidate materials efficiently by principal component analysis.

增材铜合金拉伸力学行为的卷积神经网络预测

深度学习因其在处理复杂数据和解决复杂问题方面的显著优势而备受关注,已应用于材料性能预测领域。本文提出了一种结合卷积神经网络模型与晶体塑性有限元方法的预测框架,在晶体塑性模型中考虑了增材铜合金(CuCrZr)固溶强化、位错强化以及晶界强化的贡献,实现了基于增材铜合金的晶体学织构极图、微结构图和晶粒尺寸预测单轴拉伸力学行为的目标。首先,基于实验结果对晶体塑性模型参数进行校正,验证了模型的准确性及预测能力。随后,使用参数校正后的晶体塑性模型对增材铜合金不同的代表体积元进行了一系列的有限元模拟,并利用这些模拟结果对卷积神经网络模型进行了训练、验证与测试。研究结果表明,该卷积神经网络模型在保证预测精度的同时,显著减少了计算时间,展示了其在增材铜合金力学性能预测方面的应用前景。

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.

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。

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.