温敏性荧光纳米微球的聚合物配方筛选与制备EI北大核心CSCD

文中使用喷墨打印的方法制备包埋有荧光共轭聚合物(FCP)的聚丙烯酸酯微点阵列芯片,通过对微点的荧光强度分析筛选出对FCP具有荧光增益效应的聚合物配方,并以此配方进行放大实验制备了包埋有荧光共轭聚合物的荧光纳米微球。通过红外光谱、紫外、扫描电子显微镜、透射电子显微镜、荧光分析等对荧光纳米微球的组成及性能进行了分析。结果表明,通过控制单体的配方比例可获得使FCP荧光强度增强的荧光纳米微球,并且发现其具有温敏性,荧光强度随着温度的升高而减弱,降低而恢复。细胞毒性及成像实验表明,荧光纳米微球具有良好的生物相容性,在细胞成像方面有良好的应用前景。     

分子内电荷转移荧光探针法测定表面活性剂的临界胶束浓度

研究了分子内电荷转移荧光体4-二甲氨基查尔酮(DMAC)在表面活性剂水溶液中的荧光光谱。观察到随表面活性剂浓度增大,DMAC 的荧光光谱先红移然后蓝移,而荧光强度呈“S”型变化并于光谱位移方向转折处突跃。突跃处对应的表面活性剂浓度即为其临界胶束浓度(cmc)。结果表明由该法测定的 cmc 与已报道值符合,说明方法的可行性与准确性。用该法测定表面活性剂/β-环糊精混合体系的 cmc,表明β-环糊精的存在诱导了胶束的形成。     

一种超支化共轭聚合物的合成与2,4-二硝基甲苯的荧光猝灭

以2,4,6-三甲基均三嗪和甲酰基咔唑、二甲酰基咔唑为原料,通过羟醛缩合反应合成了化合物I及超支化荧光共轭聚合物II,其中I可以视为II的组成单体。聚合物II在常见有机溶剂中有较好的溶解度,其X射线衍射谱图中2θ=24.2°的位置有1个较宽的峰;其吸收和荧光光谱与I的相比仅有轻微红移(3nm),这些结果都说明聚合物II分子间没有紧密的π-π堆积作用。聚合物II的荧光强度是化合物I的2倍。2,4-二硝基甲苯对其荧光猝灭研究结果表明,超支化聚合物II具有比化合物I更大的荧光猝灭常数(Ksv=95.52L/mol),表现出了一定的分子导线效应。     

共轭聚合物荧光传感器

共轭聚合物由于存在分子线效应，比传统荧光小分子相比，作为传感器具有更高的灵敏度。本文介绍了共轭聚合物荧光信号放大机理，并举例说明了几种常见了的共轭聚合物荧光传感器的应用。     

稀土Eu配合物液晶聚合物性能研究

介绍了一类含Eu配合物的新型荧光液晶聚合物材料。通过把手性液晶单体M1(烯丙氧基苯甲酸胆甾醇酯,液晶区间达132.1℃)和具有荧光性能的金属稀土E+3配合物(C3)接枝到含氢硅氧烷上,制备得到含有稀土3价Eu配合物的侧链液晶聚合物。研究了Eu配体的共轭作用与荧光性能的关系。在紫外光激发下,该聚合物在室温下就显示较强的荧光,主波长为617 nm,Eu含量在4%~8%范围内荧光强度随Eu含量的增加而增强,Eu含量达到8%时,荧光最强,低于和高于8%,荧光强度下降。单体C3的荧光配合物的荧光强度仅为其荧光液晶聚合物在主波长荧光强度的30%,揭示了荧光液晶聚合物的优势。与不含Eu的聚合物相比,液晶织构类型不变,但熔点略有升高,而清亮点呈下降趋势。这类材料除具有配合物荧光性外,其液晶性的存在使加工性提高。该类新材料尚处于理论研究阶段,但为应用研究提供了基础,并揭示该类材料广阔的应用前景。     

荧光介孔二氧化硅纳米粒子的制备及其性能探究

利用单层十六烷基三甲基溴化铵(CTAB)表面活性剂包覆染料并将其转相到水中,通过溶胶-凝胶法制备以荧光染料为核、介孔二氧化硅纳米粒子(MSNs)为壳的荧光介孔二氧化硅纳米粒子。利用DLS探讨了正硅酸乙酯、表面活性剂、氨水、染料浓度对粒子粒径的影响,利用SEM、TEM、TG、UV、PL光谱分析手段对复合纳米粒子结构、形貌、热稳定性、光谱进行了表征和探讨。结果表明,随着正硅酸乙酯和氨水用量增多,粒子粒径增加;表面活性剂用量较少时粒径会较大;染料浓度较低时对粒径影响较小;制备出的粉体可以在100nm左右可控;荧光强度提高、染料与二氧化硅最佳掺杂质量比为1.5×10-3;由于是物理包覆所以热稳定性提高有限,但抗紫外耐老化性有显著的提高。     

温敏性荧光纳米微球的聚合物配方筛选与制备

文中使用喷墨打印的方法制备包埋有荧光共轭聚合物(FCP)的聚丙烯酸酯微点阵列芯片,通过对微点的荧光强度分析筛选出对FCP具有荧光增益效应的聚合物配方,并以此配方进行放大实验制备了包埋有荧光共轭聚合物的荧光纳米微球。通过红外光谱、紫外、扫描电子显微镜、透射电子显微镜、荧光分析等对荧光纳米微球的组成及性能进行了分析。结果表明,通过控制单体的配方比例可获得使FCP荧光强度增强的荧光纳米微球,并且发现其具有温敏性,荧光强度随着温度的升高而减弱,降低而恢复。细胞毒性及成像实验表明,荧光纳米微球具有良好的生物相容性,在细胞成像方面有良好的应用前景。     

荧光共轭聚合物的合成策略及其应用研究

有机共轭聚合物在发光材料中具有良好的应用前景而倍受研究者们的关注。相对于荧光小分子来说,荧光共轭聚合物具有结构多样性、功能化强、可加工性好和合成简单等优势。近年来,荧光共轭聚合物材料在化学传感、生物成像、光电器件和有害物的吸附与降解等领域显示了重要的应用价值。综述了以suzuki偶联反应聚合、Sonogashira反应聚合、Wittig-Heck-McMurry反应聚合等方法合成共轭聚合物以及在荧光调控、化学传感、刺激响应、生物细胞成像、气体吸附及有机染料降解等方面的应用。设计合成具有特异性识别、更高灵敏度、更容易加工、卓越稳定性和功能化强的荧光共轭聚合物是主要的研究方向。     

含萘单元共聚物的合成与性质研究

单体4,8-二溴-1,5-二正丁氧基萘(M-I)分别与1,4-二乙烯基-2,5-二正丁氧基苯(M-Ⅱ)和4,4′-二乙烯基联苯(M-Ⅲ),在钯催化下通过Heck耦合反应得到共轭聚合物P-1、P-2.单体和聚合物进行了1H,13C NMR、质谱、FT-IR、UV、循环伏安和荧光光谱等测试.萘基团是一种很好的荧光团,侧链上引入了丁氧基醚链,使得聚合物具有适当的溶解度.聚合物P-1、P-2具有较强的绿色荧光,它们将是一类潜在的光电高分子材料.     

超支化荧光聚合物的合成及性能

以季戊四醇为"中心核",与1,2,4-偏苯三酸酐和环氧氯丙烷反应合成超支化聚合物,利用合成聚合物分子外围的羧基与2-(4-羧基苯基-)苯并口恶唑改性乙二醇二缩水甘油醚反应,得到超支化荧光聚合物。通过TG、红外光谱和荧光光谱等手段表征了合成聚合物的热稳定性,及结构与荧光性能的关系。将2-(4-羧基苯基-)苯并口恶唑结构引入超支化聚合物分子外围,其发射光谱的峰值由568 nm紫移至528nm,同时荧光强度增强。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。