高聚物的声发射

材料在加荷形变过程中的声发射现象首先在金属材料中发现(1953年),而且已经相当广泛地用于金属材料、陶瓷材料、粘合剂粘结接头和复合材料的无损检验。凡是材料的局部缺陷地区以及在形变过程中由于     

时间相关单光子计数法测量荧光寿命

荧光寿命是激发单重态分子辐射弛豫过程的重要参数之一。对它的研究可为激发态分子运动变化微观图景及其动力学规律提供重要的信息,从而引起化学、物理学、生物学等领域的     

桥梁振动的激光干涉测量方法

为了实现对新建桥梁的质量检测及现有桥梁健康状况的定期检查,分析和评估桥梁结构振动特性,掌握抗震性能变化情况和趋势,本文提出了激光干涉测量桥梁振动频率的方法,克服了现有测量方法精度低、电磁干扰大、传输距离受限等缺点.实现了对桥梁振动情况的检测,为桥梁勘测提供了重要的分析数据,结构简单、测量精度高、应用前景广阔.     

左n-角范畴的稳定化及Grothendieck群

本文证明了左n-角范畴的稳定化范畴具有n-角结构,并证明了当n为奇数时,左n-角范畴的Grothendieck群与其稳定化范畴的Grothendieck群同构.     

基于EMD和PCA的暂态电能质量消噪

针对电能质量扰动的消噪问题,提出一种基于经验模态分解(EMD)和主成分分析(PCA)的消噪方法.方法先用EMD将信号分解为一组内蕴模态函数(IMF),对第一层IMF进行细节信息提取,然后对第二层及其后面的IMF进行PCA变换,根据噪声能量选择合适的主成分分量重构,去除各层IMF中的噪声.分别用电压聚降、电压中断、暂态脉冲、谐波及其组合进行数字仿真,和SureShrink小波阈值法、BayesShrink小波阈值法去噪结果比较,所用的方法去噪效果优于SureShrink小波阈值法、BayesShrink小波阈值法去噪结果,尤其对于电压暂降、电压中断、电压聚升这几个最重要的暂态电能质量问题消噪效果更为明显,结果证实了其有效性.     

线性代数与空间解析几何新形态教材建设的实践与思考

从线性代数与空间解析几何课程发展历史引入,对比分析传统教材内容与体系的差异,在此基础上探讨信息技术与教育教学深度融合背景下新形态教材出版的必要性,进而阐述线性代数与空间解析几何新形态教材出版创新的探索与实践,最后浅谈新形态教材建设的几点思考.     

Molecular dynamics simulation of latent track formation in α-quartz

The latent ion track in α-quartz is studied by molecular dynamics simulations. The latent track is created by depositing electron energies into a cylindrical region with a radius of 3nm. In this study, the electron stopping power varies from 3.0keV/nm to 12.0keV/nm, and a continuous latent track is observed for all the simulated values of electron stopping power except 3.0keV/nm. The simulation results indicate that the threshold electron stopping power for a continous latent track lies between 3.0keV/nm and 3.7 keV/nm. In addition, the coordination defects produced in the latent track are analyzed for all the simulation conditions, and the results show that the latent track in α-quartz consists of an O-rich amorphous phase and Si-rich point defects. At the end of this paper, the influence of the energy deposition model on the latent track in α-quartz is investigated. The results indicate that different energy deposition models reveal similar latent track properties. However, the values of the threshold electron stopping power and the ion track radius are dependent on the choice of energy deposition model.     

具有聚集荧光增强性质的双(4-二乙氨基水杨醛)缩偶氮二甲酰肼二丁基锡的合成和晶体结构

在甲醇溶液中,卡巴肼、(4-二乙氨基)水杨醛和二乙酸二丁基锡"一锅法"反应,合成了一个新颖的基于双(4-二乙氨基水杨醛)缩偶氮二甲酰肼(L)的七配位有机锡配合物[Sn(L)(n-butyl)_2]n(T)。经元素分析、IR、(1H,119Sn,13C)NMR和X射线衍射晶体结构表征,T的晶体属单斜晶系C2/c空间群,中心锡周围由双(4-二乙氨基水杨醛)缩偶氮二甲酰肼的O,N配位原子占据赤道位置和2个丁基占据顶端位置形成畸变五角双锥构型。通过烯醇式氧原子的桥联配位作用,T向一维带状无限扩展产生"竹筏状"超分子结构。配合物T在二甲基甲酰胺、四氢呋喃、乙醇、甲醇和甲苯有机溶剂及其有机溶剂-水混合物中具有强荧光发射峰,当含水量的体积分数在0～10%(V/V)时具有良好的聚集荧光增强效应,含水量大于10%(V/V)时发生荧光淬灭。     

Syntheses,Structures and Herbicidal Activity of Bis(5-R-2-hydroxybenzylidene) Thiocarbohydrazide Monobutyltin Complexes [R: H(T1), Me(T2)]

The 1,5-disubstituted thiocarbohydrazide ligands were prepared by the condensation of thiocarbohydrazide with salicylaldehyde and 5-methylsalicylaldehyde, respectively. The butyltin complexes, [(5-R-2-hydroxy)ArCH=NNH]_2 CS(n-BuSnCl)_2, R = H(T1); R = Me(T2), based on the1,5-disubstituted thiocarbohydrazide were obtained by microwave-assisted solvothermal reaction of n-butyltintrichloride precursor with the ligands in methanol environments, which have been structurally characterized by elemental analysis, IR and(~1 H, ~(13) C) NMR spectra. The crystals belong to monoclinic system, space groups C2/c(T1) and Pc(T2), respectively. The Sn atom is six-coordinated with distorted octahedral geometry by O, N and S atoms from ligand, C atom of butyl and two Cl atoms. In the crystal, complex T1 forms three-dimensional supramolecular assembly mediated by noncovalent interactions such as C–H···Cl and π-stacking interactions.Similarly, T2 forms an interesting two-dimensional supramolecular structure by noncovalent interactions(e.g. C–H×××Cl and N–H×××Cl) of one-dimensional band-like chain. These ligands and its butyltin complexes have growth effect on the target plants, such as Portulaca oleracea L.,Amaranthus spinosus L., Cassia tora L., Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee and Amaranthus tricolor L. The ligand L1 has a good inhibitory effect on the growth of Cassia tora L., and complex T2 has selective inhibition on the growth of Portulaca oleracea L. and Amaranthus tricolor L., which can be used as a candidate compound for Cassia tora L., Portulaca oleracea L.and Amaranthus tricolor L. herbicide.     

1,3,5-三(羧基甲氧基)苯镍配位聚合物的合成、晶体结构及性质研究

采用溶剂热法,1,3,5-三(羧基甲氧基)苯为定向配体和乙酸镍反应构筑了一个新型的金属配位聚合物[Ni(TB)₂(H₂O)₂]_n·2H₂O,其中H₃TB=1,3,5-三(羧基甲氧基)苯,通过元素分析、IR及X射线单晶衍射对配合物结构进行表征,并研究其荧光性质、热稳定性及Hirshfeld表面作用力。单晶结构分析表明,该配合物属于三斜晶系,空间群$P \overline{1}$,配合物中心离子Ni(Ⅱ)分别与来自两个水分子上的氧原子及四个不同1,3,5-三(羧基甲氧基)苯配体的羧酸氧原子配位,形成六配位的NiO₆八面体构型,并通过与1,3,5-三(羧基甲氧基)苯配体的氧原子配位不断延伸形成具有孔洞结构的一维链状构型。配合物具有良好的荧光性能和热稳定性。Hirshfeld表面作用分析表明配合物分子中O…H/H…O作用占主导且占比为39.0%,而H…H的作用力占比为25.9%,O…O的作用力占比为13.6%。