基于矩阵分析的STR荧光解谱技术

用多种荧光标记物进行STR检测时,由于荧光光谱的谱带展宽特性,各个荧光光谱之间有重叠部分,如何实现将相互重叠的各个波长上的能量有效利用起来,对提高荧光利用效率至关重要。本文给出了一种基于矩阵分析的数据处理方法,该方法在进行荧光探测前首先要对荧光谱进行光谱校正,即要得到每种所用标记染料受激发射荧光的光谱分布,根据光谱分布建立染料组合荧光信号矩阵,然后对矩阵进行归一,利用归一后的矩阵对所探测的荧光谱进行解谱,从而得到所期望的荧光谱图。理论分析和实验结果表明,该方法可以有效的利用各个波长的荧光光谱能量,并实现对不同荧光重叠谱的有效光谱解谱。     

用振动光谱的频率参数研究分子结构的构象变化 Ⅰ．芳香酯液晶分子的研究

通过振动光谱的频率参数，结合构象与键级的关系，观测了芳香酯液晶分子（一种高分子液晶模型化合物）在相态变化过程中的构象结构变化。认为这种液晶化合物在由晶态到液晶态的变化过程中是从酯基与苯环呈相互垂直状态到酯基与Ａ环是共平面状态而与Ｂ环不共平面即垂直的状态。     

拉曼光谱法鉴定文物及艺术品中染料的研究进展

中国是丝绸之路的发源地,染色历史源远流长。文物及艺术品中的有机染料蕴含着制作年代、原料来源、染色工艺及保存状况等丰富的信息,但因染料成分复杂、含量低、易于降解,其鉴定一直是文物分析领域的难点。拉曼光谱作为一种指纹光谱在文物及艺术品中染料分析方面具有独特的优势。系统阐述了显微拉曼光谱法(MRS/μ-Raman)、近红外傅里叶变换拉曼光谱法(NIR-FT-Raman)、表面增强拉曼光谱法(SERS)、共振拉曼光谱(RRS)法的原理、特点、局限性以及在染料鉴定中的研究进展和发展方向; 分类归纳总结出了黄栀子、姜黄等染料的拉曼光谱特性; 对比分析了紫茜素在采用不同波长激光器激发下的荧光现象; 介绍了以自制的灰绿色银胶颗粒为基底,联合薄层色谱(TLC) 分离技术及SERS鉴定茜草中的色素,表明银溶胶微粒产生的表面增强效应可显著降低拉曼光谱荧光背底。指出拉曼光谱作为一种快速、便捷的结构定性测试手段在文物和艺术品染料分析中应用前景广阔,提出多种拉曼光谱技术相结合、拉曼光谱技术与分离技术相结合以及拉曼光谱技术与远距离传导技术相结合是拉曼光谱技术的发展趋势。     

介电微球对oxazine溶液荧光的调制

研究了染料恶嗪（oxazine 1)溶液中掺有高折射率玻璃微球时，微球表面附近染料荧光的荧光光谱特性，发现微球外表面附近染料分子的荧光光谱也会象球内情况一样形成结构共振，用Mie散射理论和微腔理论对此实验现象进行了分析，实验与理论计算结果符合得较好。     

超声检测中的结构噪声

结构噪声是超声脉冲在介质结构上激发产生的一种特殊噪声，它严重妨碍超声检测，是超声检测的基本限制因素之一；但也可被利用进行某些检测。本文综述了有关结构噪声的基本研究，抑制或降低结构噪声的方法，以及在结构噪声背景下进行超声检测和利用结构噪声进行超声检测的有关工作。     

基于光谱特征拟合的艺术画颜料成分识别研究

高光谱成像技术作为一种高效无损的检测方法,根据不同的物质成分在光谱上表现出不同的光谱信息,可以从图像上方便的鉴定出物质成分组成。本文分别利用可见光高光谱与红外高光谱成像技术对一幅古画进行颜料光谱成像,通过最小噪声分离(MNF)、纯净像元提取(PPI)、光谱特征拟合方法(SFF),与标准波谱库匹配,识别出该幅古画所用颜料成分主要由:朱砂、石青、白云母和金云母等组成,匹配度分别为:0.76,0.57,0.62,0.89。实验表明:利用高光谱成像技术不但可保存图像信息,物质成分波谱信息,还可还原受污染区域,为以后深层次研究提供详实资料。     

准波导结构下染料薄膜的荧光光谱和放大自发辐射光谱特性

通过对RhB/PMMA和Rh6G/PMMA染料薄膜的荧光光谱和放大自发辐射(ASE)光谱的实验测量和理论分析,研究了准波导结构染料薄膜的荧光光谱和ASE光谱特性。实验上采用连续激光和脉冲激光照射,分别测量准波导结构RhB/PMMA和Rh6G/PMMA染料薄膜的荧光光谱和ASE光谱,发现荧光峰和ASE峰随着染料掺杂浓度和薄膜厚度的增加产生红移;理论上考虑准波导结构下薄膜中染料的自吸收效应,类比激光器谐振腔模型,分析低阶导模传输的增益特性,获得了荧光光谱与ASE光谱中荧光峰和ASE峰对应波长与染料掺杂浓度的关系,数值计算与实验测量相吻合。结果表明,准波导结构下薄膜中染料自吸收效应导致荧光峰及ASE峰发生红移,改变染料掺杂浓度,可以在较大调谐范围实现ASE。     

基于香豆素的荧光传感器及其对次氯酸根的快速检测（英文）

本文报道了两个基于香豆素染料的次氯酸根荧光传感器(化合物C2和C4),可在不同条件下实现对次氯酸根的快速响应。利用次氯酸独特的氧化性,传感器C2和C4均可实现对次氯酸根的高选择性检测。在化合物C2的溶液中加入次氯酸根之后,溶液的荧光光谱表现出极大的荧光猝灭,这有利于在检测过程中产生明显的荧光信号输出。不同的是,化合物C4则对次氯酸根表现出明显的荧光增强响应。     

利用地基红外高光谱发射率数据进行云参数反演(1): 云相态判别

云相态是气候模式中的重要参数,也是遥感反演过程中进行云滴有效半径、云水含量等微物理参数反演的重要前提。在研究了云层有效发射率光谱对云相态敏感性的基础上,提出了基于云层有效发射率光谱的云相态表达特征,包括800～900 cm-1区域的有效发射率斜率、900～1 000 cm-1区域的有效发射率斜率、上述两个区域的有效发射率斜率之差、862.1与989.8 cm-1的有效发射率之比、862.1与989.8 cm-1的有效发射率之差、1 900.1与2 029.3 cm-1的有效发射率之比、远红外窗区有效发射率平均值与900 cm-1有效发射率之比等7个特征。建立了利用支持向量机进行云相态判别的方法,开展了模拟数据验证试验,并利用遗传算法优化了支持向量机的径向基核函数参数和惩罚因子。将该方法用于处理ARM计划中SGP站点的AERI仪器获得的数据,得到的云相态判别结果与Shupe提出的多仪器综合判别结果进行了比较。结果表明,利用红外波段不同窗区的有效发射率光谱特征可以实现发射率低于0.95的云层的相态判别,建立的基于支持向量机的云相态判别方法与Shupe方法的总体判别结果较为一致,但有约30%的云层由于发射率较大而标记为不透明云。基于红外高光谱发射率数据的云相态判别技术充分考虑了光谱斜率、比值和差值等信息,是较为稳定有效的薄云相态判别方法。     

旋转光栅式光谱仪的研制与应用

根据光谱仪原理,研制了一种光栅匀速旋转式光谱仪,其特点是测量周期短、灵敏度高、结构简单和操作方便.该仪器可用于各种光谱的在线测量系统中,已成功地用于烟道SO₂浓度检测、空气中NO₂浓度检测和固体染料的荧光光谱测量中.     

Effect of temperature on the phase behavior and microstructure of aggregates in SDS/Triton X-100/aH2O systems

The phase behavior and microstructure of a system containing polyoxyethylene tert-octylphenyl (Triton X-100), sodium dodecyl sulfate (SDS) and water were investigated using polarized optical microscopy (POM), differential scanning calorimetry (DSC) and small-angle X-ray diffraction (XRD). Phase-behavior study revealed that lamellar and hexagonal phases occurred in different compositions, and that lyotropic liquid crystal phases tended to form an H phase with increased Triton X-100 content. The effects of temperature on the phase behavior and microstructure of lyotropic liquid crystals were also studied. Heating induced a change from hexagonal to lamellar phase and from gel to hexagonal phase. POM and small-angle X-ray diffraction (SXRD) revealed that the phase-transition temperature of LLCs increased with increased Triton X-100 content, as further supported by DSC data.     

Supramolecular polymorphism of DNA in non-cationic L<Subscript>α</Subscript> lipid phases

The structure of a complex between hydrated DNA and a non-cationic lipid is studied, including its phase diagram. The complex is spontaneously formed by adding DNA fragments (ca. 150 base pairs in length) to non-cationic lipids and water. The self-assembly process often leads to highly ordered structures. The structures were studied by combining X-ray scattering, fluorescence and polarized microscopy, as well as freeze-fracture experiments with transmission electron microscopy. We observe a significant increase of the smectic order as DNA is incorporated into the water layers of the lamellar host phase, and stabilization of single phase domains for large amounts of DNA. The effect of confinement on DNA ordering is investigated by varying the water content, following three dilution lines. A rich polymorphism is found, ranging from weakly correlated DNA-DNA in-plane organizations to highly ordered structures, where transmembrane correlations lead to the formation of columnar rectangular and columnar hexagonal superlattices of nucleotides embedded between lipid lamellae. From these observations, we suggest that addition of DNA to the lamellar phase significantly restricts membrane fluctuations above a certain concentration and helps the formation of the lipoplex. The alteration of membrane steric interactions, together with the appearance of interfacial interactions between membranes and DNA molecules may be a relevant mechanism for the emergence of highly ordered structures in the concentrated regime.     

Freeze-fracture studies on lipids and membranes

Freeze-fracture electron microscopy is especially useful for investigation of lipid structures by the advantageous fracture course within hydrophobic zones. Freezing is, on the other hand, a restriction because the structures of lamellar and non-lamellar phase states with disordered acyl chains (L(alpha), H(II,) cubic) are difficult to preserve. An important aspect of this method is therefore the lipid structure of phase states with ordered acyl chains (crystal, gel), and with a different degree of hydration. Freeze-fracture of pure lipid systems creates a valid representation of the structure of non-lamellar phases and of the general structure of the "lamellar" lipid bilayer, and lamellar phases with characteristic deformations (ripples, curvatures, plane sectors) can be identified. Fracture through the hydrophobic bilayer centre of biological membranes reveals characteristic protein components, the intramembraneous particles (IMPs). The lateral distribution of the IMPs is a helpful marker for fluid and rigid phase states, also without deformation of the lamella. The overall history and the present state of knowledge concerning the different structures revealed by the freeze-fracture and freeze-etch techniques in lipid systems, and to a limited extent in biological membranes, is reviewed, taking into account studies from our own laboratory.     

Phase behavior and structure of an ABC triblock copolymer dissolved in selective solvent

A mean-field lattice theory is applied to predict the self-assembly into ordered structures of an ABC triblock copolymer in selective solvent. More specifically, the composition-temperature phase diagram has been constructed for the system (C)₁₄(PO)₁₂(EO)₁₇/water, where C stands for methylene, PO for propylene oxide and EO for ethylene oxide. The model predicts thermotropic phase transitions between the ordered hexagonal, lamellar, reverse hexagonal, and reverse cubic phases, as well as the disordered phase. The thermotropic behavior is a result of the temperature dependence of water interaction with EO- and PO-segments. The lyotropic effect (caused by changing the solvent concentration) on the formation of different structures has been found weak. The structure in the ordered phases is described by analyzing the species volume fraction profiles and the end segment and junction distributions. A “triple-layer” structure has been found for each of the ordered phases, with each layer rich in C-, PO-, and EO-segments, respectively. The blocks forming the layers are not stretched. The dependence of the domain spacing on polymer volume fraction and temperature is also considered. Received 17 April 2002 Published online: 21 January 2003     

声学蜂窝结构中的拓扑角态

高阶拓扑绝缘体是近年来发现的一类具有特殊拓扑相的新型拓扑绝缘体,目前已在光学、声学等多种经典波系统中实现.本文采用数值模拟方法研究了一种二维声学蜂窝结构,通过调节胞内和胞间耦合波导管,使体能带发生反转诱导拓扑相变,进而利用拓扑相构建出声学二阶拓扑绝缘体.蜂窝结构的拓扑性质可以用量子化的四极矩Q_ij表征,当Q_ij=0时,系统是平庸的;而当Q_ij=1/2时,系统是拓扑的.基于该蜂窝结构,分别研究了六边形和三角形结构的声学高阶态,在两种构型的蜂窝结构中均观测到了孤立的零维角态,研究结果表明只有存在钝角的六边形结构对缺陷具有鲁棒性,受拓扑保护.本文的拓扑角态丰富了高阶拓扑绝缘体的研究,同时可为紧凑声学系统中的鲁棒限制声提供一条新途径.     

Microphase separation in polymer solutions containing surfactants

A microphase separation in solutions containing a polymer and a mixture of two solvents, one of which consists of amphiphilic molecules (surfactant), is considered theoretically in the weak-segregation regime. A surfactant molecule is described as a dimer consisting of hydrophobic and polar parts. The energy gain due to the orientation of surfactant molecules can lead to the appearance of non-homogeneities in the solution, where density fluctuations cause the orientational ordering of surfactant molecules. The difference in the interaction energies of hydrophobic and polar groups of a surfactant with solvent is considered as a main reason for orienting surfactant molecules. The free energy is calculated for various morphologies (lamellar, cylindrical hexagonal, spherical particles arranged at different cubic lattices). The phase diagrams are presented. With worsening the solvent quality, the transitions from disordered to a macro-separated state at low polymer and surfactant concentrations or to a body-centered-cubic, then hexagonal, and then lamellar structure at high polymer and surfactant concentrations are predicted. The amphiphilicity degree of surfactant molecules should exceed a certain critical value to make a microstructure formation possible. The period of the lamellar microstructure decreases with increasing the surfactant and polymer concentrations.     

六边形格子态斑图的数值模拟

采用双层耦合的Lengel-Epstein模型, 通过改变两子系统图灵模的强度比, 获得了四种的六边形格子态和多种非格子态结构. 模拟结果表明: 反应扩散系统的格子态结构由三套子结构叠加而成, 是两图灵模的波数比和强度比共同作用的结果, 两模的强度比决定了三波共振的具体模式; 另外, 系统选择格子态斑图所需的两图灵模的强度比大于非格子态斑图的强度比; 逐步增加两图灵模强度比, 出现的斑图趋于从复杂到简单变化. 深入研究发现: 不同互质数对(a, b)对应的格子态斑图的稳定性不同, 其中(3, 2)对应的格子态结构最为稳定.     

NMR studies of restricted diffusion in lyotropic systems

Tortuosity, 1/alpha, and surface-to-volume ratio, S/V, were determined in aqueous solutions of decylammonium, dodecylammonium and tetradecylammonium chlorides of various concentrations by measuring the apparent diffusion coefficient of water, D(app)(delta). This was found to be much smaller than in the bulk state. Such restricted diffusion is interpreted in terms of the Mitra model, where D(delta) depends on diffusion time and is controlled primarily by S/V. The samples exhibit lamellar (L), hexagonal (H) and isotropic (I) liquid crystalline phases. We observed changes in S/V upon phase transition. In the lamellar and hexagonal phases, the system is ordered, resulting in relatively small S/V ratios, compared to the micellar-isotropic phase. We did not observe a dependence on the diffusion time, delta, in the isotropic phase, because the duration of the experiment was not sufficiently short to observe the change from D(app)(delta) to D(eff). We observed the effective diffusion coefficient of water, which directly probes the tortuosity of the system. The S/V ratios were obtained by fitting the Mitra model, using known values of the bulk water diffusion coefficients, and the assumption that D(app) --> D0 for delta --> 0. S/V is correlated with the type of structure, increasing on transition to the isotropic phase and decreasing on transition to other phases. The change in tortuosity is small, but slightly larger for the isotropic phase.     

Nucleation and collapse of the superconducting phase in type-I superconducting films

The phase transition between the intermediate and normal states in type-I superconducting films is investigated using magneto-optical imaging. Magnetic hysteresis with different transition fields for collapse and nucleation of superconducting domains is found. This is accompanied by topological hysteresis characterized by the collapse of circular domains and the appearance of lamellar domains. Magnetic hysteresis is shown to arise from supercooled and superheated states. Domain-shape instability resulting from long-range magnetic interaction accounts well for topological hysteresis.     

嵌段共聚物溶致液晶相中水的2H-NMR动力学分析

采用D₂O 的²H-NMR线型和弛豫分析了PEO-PPO-PEO/D₂O/对二甲苯体系的层状和六角液晶相的动力学行为. 通过实验测得了两个不同体系的自旋 晶格弛豫时间T₁、自旋-自旋弛豫时间T₂和²H-NMR 谱. ²H-NMR 谱均为具有四极劈裂的粉末谱线型，且在谱图的中心，β_LD=54.7°时存在一个倒峰. 倒峰的出现直接表明引起体系中弛豫的主要动力学过程处于极窄化区域. 采用NMR弛豫模型，通过调节动力学参数，使理论模拟的²H-NMR谱、弛豫时间、倒峰的大小与实验的对应量相吻合，求得了体系的动力学参数.