温度对PEEK太赫兹光谱特性影响研究

聚醚醚酮(PEEK)由于其耐热、耐腐蚀、耐辐照、抗疲劳、电绝缘性等优良性能,在许多领域可以代替金属、陶瓷等传统材料而得到广泛应用。特别是随着5G技术的发展和应用,PEEK已经成为5G热门材料。在PEEK材料实际应用中,温度的影响是一个非常重要和关键的因素。主要研究了PEEK太赫兹光谱以及温度对PEEK太赫兹光谱特性的影响。通过利用太赫兹透射光谱技术,同时结合控温装置,在温度从25～300℃均匀上升过程中,每间隔5℃测试得到PEEK片状样品的太赫兹时域光谱数据,利用光学参数提取算法可以得到PEEK的吸收系数、介电常数等光学参数,进一步得到特定频率下光学常数随温度的变化趋势,从而对材料进行表征和分析。在0.5～4 THz有效光谱范围内,实验结果表明,在常温(25℃)下,PEEK在3.5 THz具有一个明显的特征吸收峰。在25～300℃这个温度范围内,在1 THz频率下,PEEK的吸收系数、介电常数相对于室温分别有4.38%和5.0%的波动,同时PEEK在常温下在1 THz的介电损耗正切值为2.5×10^-3,相比于PMMA和PE等高分子材料,PEEK的介电损耗正切值要低...     

Synthesis,Crystal Structure and Antimicrobial Property of 4-Bromo-2-[(3-methypyridin-2-ylimino)methyl]phenol

The title Schiff base compound 4-bromo-2-[(3-methylpyridin-2-ylimino)me-thyl]phenol was prepared and structurally characterized by elemental analysis,IR spectrum,and single-crystal X-ray diffraction.The crystal belongs to monoclinic,space group P21/n,with a=4.4870(9),b=19.953(4),c=13.860(3)(A),β=93.13(3)°,V=1239.O(4)(A)3,Z=4,Dc=1.561g/cm3,C13H11BrN2O2,Mr=291.15,μ=3.302mm-1 and F(000)=584.The final refinement gave R =0.0608 and wR=0.1377 for 1329 observed reflections with I＞2σ(I).X-ray diffraction reveals that the non-hydrogen atoms in the compound are nearly coplanar,with the mean deviation of 0.0197 (A) from the plane.The molecule adopts an E configuration about the central C=N functional bond.The compound possesses moderate antimicrobial property.     

A Novel （4,6）-Connected Net Based on Dysprosium Benzenedicarboxylate, [Dy（OAc）（BDC）]n

A new lanthanide coordination polymer, [Dy（OAc）（BDC）]n 1 （OAc = acetate, BDC = 1,4-benzenediacarboxylate）, has been synthesized under hydrothermal conditions. Single-crystal X-ray diffraction analysis reveals that complex 1 has infinite zigzag Dy-OAc chains, which are further connected by BDC to form a 3D metal-organic framework. According to topology analysis, this framework can be characterized as （4,6）-connected （3.4.54）（32.4.56.66） net that has never been reported before. Crystal structure for 1： space group Pbca, a = 13.314（3）, b = 8.0269（18）, c = 20.275（5）A, V= 2166.8（9）A3, C10H7O6Dy, Mr = 385.66, Z= 8, Dc = 2.364 g/cm^3, μ= 6.910 mm^-1, F（000） = 1448, the final R = 0.0181 and wR = 0.0520.     

Synthesis and Crystal Structure of a New Double 2D Layer Complex Assembled by H4btec

Assembly of H4btec with cobalt（Ⅱ） acetate afforded a new double 2D layer coordination polymer, [Co（bteC）1/2（H2O）4·2H2O]n （H4btec = benzene-1,2,4,5-tetracarboxylic acid） 1. The polymeric structure has been characterized by single-crystal X-ray diffraction, FT-IR and thermal analysis. The crystal is of triclinic, space group PI with a = 10.8762（2）, b = 11.1411（1）, c = 11.5084（3） A, a = 82.8950（10）, β = 63.0050（10）, γ = 62.1500（10）°, V = 1091.72（4） A^3, C5H13CoO10, Mr= 292.08, Z = 4, Dc = 1.777 g/cm^3, μ = 1.612 mm^-l, F（000） = 600, R = 0.0578, and wR = 0.2162 for 3576 observed reflections （Ⅰ 〉 2σ（Ⅰ））. Complex 1 consists of a new double 2D layer structure [Co（btec）1/2（H2O）4]n, both consisting of 4 ＋ 4 grids with the sizes of 11.3667（2）A × 11.5084（3）A （Co（1）-Co（1A） × Co（2A）-Co（2B）） and 11.5084（3）A × 11.3667（2）A （Co（3）-Co（3C） × Co（4）- Co（4A））, respectively. The phenyl rings are at the comers while the Co（Ⅱ） atoms are in the sides of the grids, and lattice water molecules decorate between the layers. Hydrogen bonds between the layers and lattice water molecules result in the final 3D framework.     

Synthesis and Molecular Structure of 3-（p-Methoxyphenyl）-4-hydroxymethyl-6-bromo- 7-hydroxycoumarin Co-crystallized with Methanol

The title compound, C18H17BrO6 （Mr = 409.23）, was synthesized as angiogenesis inhibitor and structurally characterized by ^1H-NMR, ^13C-NMR, MS, elemental analysis and X-ray single-crystal diffraction. Structure analysis indicates that the title compound is of triclinic, space group P1^-, with a = 8.100（3）, b = 10.536（4）, c = 11.689（5）A, a = 67.405（7）, βl = 69.736（3）, γ = 88.510（5）°, V = 857.3（5） A^3, Z = 2, Dc = 1.585 g/cm^3, μ = 2.429 mm^-1, F（000） = 416, the finial R = 0.0356 and wR = 0.0929 for 2541 observed reflections. The bond lengths of C（7）-C（16） proved that the title compound possesses coumarin rather than flavone scaffold.     

顺铂前药接枝修饰硫代DNA及其自组装靶向纳米药物研究

选用具有良好生物相容性的硫代修饰嵌段核酸为载体,将其非硫代修饰部分设计为靶向MUC-1蛋白的核酸适配体序列,同时在其硫代修饰部分通过硫代磷酸酯基团(Phosphorothioate, PS)接枝修饰四价顺铂前药,制备了两亲性核酸-顺铂前药缀合物MUC-1/^PODNA-b-(^PSDNA-g-Pt),并进一步自组装成类似球形核酸(Spherical nucleic acid, SNA)的含铂靶向纳米药物(MUC-1/Pt-SNAs).结果表明,该纳米药物递送体系载药率高、形貌稳定、分散性好,能够高效靶向MUC-1蛋白过表达的MCF-7乳腺癌细胞,并在体内外实验中表现出优异的抗肿瘤效果和极低的毒副作用.     

Schwarz Lemma at the Boundary on the Classical Domain of Type Ⅲ

Let R_Ⅲ(n) be the classical domain of type Ⅲ with n≥2. This article is devoted to a deep study of the Schwarz lemma on R_Ⅲ(n) via not only exploring the smooth boundary points of R_Ⅲ(n) but also proving the Schwarz lemma at the smooth boundary point for holomorphic self-mappings of R_Ⅲ(n).     

泵浦光激发下金刚石纳米柱内部光场的研究

金刚石纳米柱是实现色心单光子源增强的有效结构,而纳米柱结构尺寸决定泵浦光对色心的激发强度.本文为提高其激发效率,采用时域有限差分法(Finite Difference Time Domain, FDTD)研究金刚石纳米柱的光学性质.通过仿真分析了纳米柱直径和高度对内部电场强度的影响.结果表明,在泵浦光波长为532 nm时,纳米柱内部中轴线上场强受尺寸变化影响较大,当直径不变、改变高度时,场强最大值随高度周期性变化,周期约为150 nm;当高度不变、改变直径时,场强最大值也随直径周期性变化,周期约为150 nm.通过研究不同波长的泵浦光对金刚石纳米柱内部中轴线上电场分布的影响发现,不同波长的泵浦光对纳米柱内部中轴线上最强场强对应的纳米柱尺寸有较大影响,但对于纳米柱最大场强随纳米柱尺寸变化的趋势几乎没有影响.本文通过研究上述内容,较为全面地掌握了纳米柱尺寸及泵浦光对纳米柱内部电场强度的影响规律,找到了纳米柱内部中轴线上最强场强位置,确定了激发色心的效率最高值所在位置,为金刚石纳米柱单光子源的制备提供理论指导.     

地磁环境下基于SQUID三轴磁强计的矢量稳场

超导量子干涉器件(Superconducting Quantum Interference Device,简称SQUID)是一种高灵敏度的矢量磁探测器.本文采用低温超导SQUID作为传感器,搭建了一套三轴矢量磁场稳定装置.该系统由两个三轴SQUID磁强计模块、比例积分微分(PID)控制器和反馈线圈组组成.在该系统的矢量稳场下,磁场波动峰峰值在有效带宽内可以降低四个数量级,可达pT量级,稳场效果显著.此技术可以满足大部分需要稳定磁场,如高灵敏度磁传感器的标定等应用场合.     

基于电热模型的SNSPD响应过程模拟与时间抖动分析

超导单光子探测器(SNSPD)具有高探测效率,低时间抖动、低暗计数率、高计数率等优点.文章通过对纳米线电热过程的建模,分析了纳米线的电热响应过程,探讨了负载电阻、偏置电流和动态电感对SNSPD响应时间的影响,结合蒙特卡洛方法来模拟研究了纳米线空间不均匀性对于SNSPD时间抖动的影响,结果表明随着纳米线空间不均匀性的增加,纳米线的时间抖动不断增加,并求出了典型的时间抖动约为7.73 ps.