基于等离激元纤维素微丝的微流控SERS检测实验研究

在实验工作中,将Ag纳米粒子包覆于纤维素微丝表面,获得等离激元纤维素微丝,将其置于微流通道中组装成一种新型微流控芯片,用于微流控的SERS检测。受益于等离激元纤维素微丝分布在微流管道中对管道空间的高利用,溶液中的微量分子更容易聚集在Ag纳米粒子周围进行拉曼增强。为了获得高灵敏度,对纤维素微丝的结构进行了纯化、羧化处理,从该微流控芯片中收集到的SERS光谱表明:等离激元纤维素微丝在检测时具有很高的灵敏度,最低检测限可达10^(-13)mol/L,并且在SERS检测中具有良好的可重复性。实验表明,这种带有等离激元纤维素微丝的微流控SERS检测系统在在线SERS检测中具有很高的灵敏度,在人体体液检测领域呈现出较好的应用前景。

垃圾分类快速发展阶段动态分类模式

“十三五”以来,我国垃圾分类已进入快速发展阶段,但地区与社区的情况复杂多样,现有垃圾分类模式的优缺各异,仍然缺乏可推广、可持续的垃圾分类投放、源头减量与资源化模式。文章根据市场化程度梳理了现有的典型模式,总结了14个分类要素,利用层次分析法和逼近理想解排序法量化分析了分类要素在发展阶段前期和后期的综合评价值,在前中期,物质奖惩、桶站指导人员和撤桶并站等较为有效;在中后期,以社区物业或管理组织作为责任主体、精神奖惩、按类计量收费和定时定点等措施相对适用。最后,该研究构建了4个动态发展的垃圾分类主型模式。

Plasmonic hybridization properties in polyenes octatetraene molecules based on theoretical computation

Relationship of plasmonic properties of multiple clusters to molecular interactions and properties of a single cluster or molecule have become increasingly important due to the continuous emergence of molecular and cluster devices or systems.A hybrid phenomenon similar to plasmonic nanoparticle hybridization exists between two molecules with plasmon excitation modes.We use linear-response time-dependent density functional theory,real-time propagation time-dependent density functional theory,the plasmonicity index,and transition contribution maps(TCMs)to identify the plasmon excitation modes for the linear polyenes octatetraene with–OH and–NH_(2)groups and analyze the hybridization characteristics using charge transitions.The results show that molecular plasmon hybridization exists when the two molecules are coupled.The TCM analysis shows that the plasmon modes and hybridization result from collective and single-particle excitation.The plasmon mode is stronger,and the individual properties of the molecules are maintained after coupling when there is extra charge depose in the molecules because the electrons are moving in the molecules.This study provides new insights into the molecular plasmon hybridization of coupled molecules.

向列相溶致液晶旋转黏度研究

溶致液晶具有良好的生物相容性、无毒性、生物降解性以及光学、电磁学各向异性等,在细胞相互作用、神经刺激传递、脂肪吸收、药物智能输运等生命活动研究、医药工程和液晶显示等领域有广泛应用.本文采用旋转磁场法测得溶致液晶日落黄在不同温度和溶液浓度下向列相时旋转黏度,并结合溶致液晶分子自组装过程,理论分析了溶致液晶向列相旋转黏度随温度和溶液浓度的变化规律.研究结果表明:溶致液晶旋转黏度与液晶分子自组装柱状体平均长度的平方呈正比增大关系,随溶液浓度的增大而增大,随温度的升高表现出指数减小的规律.构建了与向列相溶致液晶温度和浓度相关的旋转黏度经验表达式,经验表达式计算结果与实验值吻合较好,最大误差仅为18.56%.提出采用旋转流变仪间接获得溶致液晶剪切能的新方法,溶致液晶剪切能随溶液浓度的增大而增大,但在实验温度范围内,溶致液晶剪切能几乎不随温度而改变.利用旋转流变仪间接获得的溶致液晶剪切能与报道的利用X-Ray检测所得的结果之间最大误差仅为3%.成功地利用了液晶分子自组装能力随温度的变化规律来研究柱状体长径比对旋转黏度的影响规律,创新地提出了“一步法”测量研究,大大减少相关实验研究的成本和复杂性.

声光衍射实验的衍射距离读取软件设计

声光衍射是大学物理中的一个重要实验,涉及声光相互作用及光的衍射等相关知识。本文尝试设计从衍射图像中获取衍射信息的软件,即获取各级衍射斑纹对应的衍射距离,并计算出超声波速,以解决实验中通过手动描点测量引入的误差问题。本文设计的软件通过Matlab程序运行,首先把理想的衍射图像转化为灰度图,通过判定衍射斑点的位置后,以固定距离的标尺来获取衍射距离。本文对软件测量过程中所涉及的斑点连续和光标位置的确定等问题进行了讨论,并在最后通过真实的衍射斑点图像进行了测量验证。

Self-assembly 2D plasmonic nanorice film for surface-enhanced Raman spectroscopy

As an ultrasensitive sensing technology,the application of surface enhanced Raman spectroscopy(SERS)is one interesting topic of nano-optics,which has huge application prospectives in plenty of research fields.In recent years,the bottleneck in SERS application could be the fabrication of SERS substrate with excellent enhancement.In this work,a two-dimensional(2D)Ag nanorice film is fabricated by self-assembly method as a SERS substrate.The collected SERS spectra of various molecules on this 2D plasmonic film demonstrate quantitative detection could be performed on this SERS substrate.The experiment data also demonstrate this 2D plasmonic film consisted of anisotropic nanostructures has no obvious SERS polarization dependence.The simulated electric field distribution points out the SERS enhancement comes from the surface plasmon coupling between nanorices.And the SERS signals is dominated by molecules adsorbed at different regions of nanorice surface at various wavelengths,which could be a good near IR SERS substrate for bioanalysis.Our work not only enlarges the surface plasmon properties of metal nanostructure,but also exhibits the good application prospect in SERS related fields.

磁场中激光牵引热解石墨的理论与实验研究

利用钕铁硼永磁体搭建了悬浮平台,抗磁性物质热解石墨片做悬浮物,在光热效应下,研究了激光牵引磁悬浮热解石墨的运动机制.从悬浮物受力公式出发,将其分为磁场与热场2部分影响,结合Matlab给出理论公式与实验方案,通过实验验证了理论的自洽性.使用COMSOL进行数值模拟,给出定位情况下的受力情况、磁场分布以及热场分布等.使用COMSOL建立了相关APP,可以得到磁铁序列的磁场分布、势场分布、热解石墨片的热场分布及其在磁场中任意位置的受力.

Light focusing in linear arranged symmetric nanoparticle trimer on metal film system

Benefiting from the induced image charge on film surface,the nanoparticle aggregating on metal exhibits interesting optical properties.In this work,a linear metal nanoparticle trimer on metal film system has been investigated to explore the novel optical phenomenon.Both the electric field and surface charge distributions demonstrate the light is focused on film greatly by the nanoparticles at two sides,which could be strongly modulated by the wavelength of incident light.And the influence of nanoparticle in middle on this light focusing ability has also been studied here,which is explained by the plasmon hybridization theory.Our finding about light focusing in nanoparticle aggregating on metal film not only enlarges the novel phenomenon of surface plasmon but also has great application prospect in the field of surface-enhanced spectra,surface catalysis,solar cells,water splitting,etc.

面包的吸声性能

多孔材料因其优异的吸声性能在声学领域有深入的研究和广泛的应用。面包作为一种典型的多孔材料,其声学性能少有人关注。本文探究了面包制备工艺的对其声学性能的影响规律。本文主要通过研究酵母菌用量,发酵时间,厚度,面水比例,面筋强度的不同来探究对其吸声效率的影响。实验结果表明:实验用量酵母菌4g,发酵时间40min为宜,在此条件上,增加厚度,面水比例,面筋强度可以进一步增强吸收率,增强面包品质。

Near-Infrared Properties of Hybridized Plasmonic Rectangular Split Nanorings

The near-infrared properties of gold rectangular split nanorings （RSNs） are investigated by simulation using the finite element method. In the results, the distribution and enhancement of electromagnetic （EM） fields are confirmed by the distribution of charge and current density. The spectrum variation with split distance of RSNs in absorption is in accordance with the hybridization theory. The influence of split distance and light wavelength on the enhancement of EM field is also studied for devices that make use of surface plasmon resonance in nearinfrared, such as in optical trapping, biomedicine, and solar energy. Additionally, the spectra in mediums with various refractive indices suggest the potential application of the hybridized plasmonic RSNs as an ultra-sensitive sensor in the near-infrared region.

二维Mxenes-Ag微纳复合膜表面增强拉曼研究

作为新兴的超高灵敏检测技术,表面增强拉曼光谱(SERS)在环境、医药、食品、生理检测等多个领域有巨大的应用前景。由于该技术的检测灵敏度完全依赖于等离激元微纳结构的理化特性,其增强基底的设计和制备成为该领域的研究关键和热点。本文采用二维MXenesAg微纳复合膜作为增强基底,并通过优化Ag纳米颗粒的大小和分布来系统研究其SERS检测性能。相比传统的SERS增强基底,二维MXenes-Ag微纳复合膜具有更大的比表面积和更多的增强位点,MXenes作为吸附层的同时也可以为拉曼检测分子提供电子,使得检测分子发生电荷转移,在电荷转移的过程中会增强拉曼信号的强度,更容易吸附检测分子以获得更大的SERS增强。研究结果表明,该基底对典型SERS探针分子耐尔蓝(NB)与亚甲基蓝(MB)的检测限分别为1×10^(-11)和1×10^(-12)mol·L^(-1)。此外,为分析该SERS增强基底的应用潜力,其增强SERS信号的重现性和均匀性也进行了探究,典型环境污染物福美双和食品添加剂三聚氰胺的检测限为10和100μg·ml^(-1)。本研究成果拓展了SERS增强基底的研究领域,对SERS技术的广泛应用提供了技术支撑。