石墨炉原子吸收光谱法测定红薯粉丝中的痕量铅含量

为建立对红薯粉丝中有害元素铅含量的测定方法,采用微波消解法处理红薯粉丝样品,加入2％NH4H2PO4和0．2％Mg（NO3）：混合液作为基体改进剂,用石墨炉原子吸收分光光度法测定了红薯粉丝中铅含量。结果表明,红薯粉丝样品中铅在2．0—40．0ng／mL的范围内吸光度与含量呈良好的线性关系（r=0．9956）,平均回收率为98．06％,RSD=1．67％（n=5）。可见该法简单、准确,可作为检测红薯粉丝中铅含量的方法。     

C60-丙烯酸月桂酯共聚物的合成及其摩擦学行为

合成了一种新颖的油溶性C60-丙烯酸月桂酯共聚物,采用四球摩擦磨损试验机、扫描电子电镜研究了其作为液体石蜡润滑添加剂的摩擦学特性,结果表明,C60-丙烯酸月桂酯共聚物可提高石蜡基础液的抗磨性能,改善微观磨损状态.     

遗传算法在结构优化中的研究进展

遗传算法(genetic algorithm)是基于Darwin的进化论和Mendal遗传学说而形成的新算法,具有全局收敛性和并行性,适用性广,并要求较少的先验知识,现在已广泛应用于优化、模式识别等方面.本文简要地介绍了简单遗传算法的基本过程及其数学基础;并从编码机制、收敛性和算子的研究等方面详细地阐述了遗传算法理论的发展;对约束处理方式、适应值函数的选取等方面的研究进行分析和评论;最后还提出遗传算法存在的主要问题和展望.      

流动注射化学发光抑制法测定抗坏血酸

基于抗坏血酸对Ｌｕｍｉｎｏｌ－ＫＩＯ４－Ｈ２Ｏ２体系化学发光反应的抑制作用,建立了化学发光抑制快速测定抗坏血酸的新方法。该方法线性范围为１．０＊１０＾－７－１．０＊１０＾－５ｍｏｌ／Ｌ,检出限为６．０＊１０＾－８ｍｏｌ／Ｌ,对８．０＊１０＾－７ｍｏｌ／Ｌ抗坏血酸１１次平行测定的相对标准偏差为１．０％。用于维生素Ｃ片剂及注射液中抗坏血酸含量的测定,结果令人满意。     

Quadrangular Prism: A Unique Self‐Assembly from Amphiphilic Hyperbranched PMA‐b‐PAA

The novel hyperbranched poly(methyl acrylate)‐block‐poly(acrylic acid)s (HBPMA‐b‐PAAs) are successfully synthesized via single‐electron transfer‐living radical polymerization (SET‐LRP), followed with hydrolysis reaction. The copolymer solution could spontaneously form unimolecular micelles composed of the hydrophobic core (PMA) and the hydrophilic shell (PAA) in water. Results show that the size of spherical particles increases from 8.18 to 19.18 nm with increased pH from 3.0 to 12.0. Most interestingly, the unique regular quadrangular prisms with the large microstructure (5.70 μm in length, and 0.47 μm in width) are observed by the self‐assembly of unimolecular micelles when pH value is below 2. Such self‐assembly behavior of HBPMA‐b‐PAA in solution is significantly influenced by the pH cycle times and concentration, which show that increased polymer concentration favors aggregate growth.

     

Self-Catalyzed Hydroxyl-Yne Click Reaction: A Powerful Tool toward Red-Emitting Nontraditional Small Organic Luminogens

Nontraditional small organic luminogens (NTSOLs) without classic conjugated chromophores have attracted significant attention. However, the design and synthesis of NTSOLs with fluorescence in the red region remain significantly challenging. In this study, we established a self-catalyzed hydroxyl-yne click reaction for preparing long-wavelength and red-emitting NTSOLs. Owing to their perfect reaction selectivity, high efficiency, and excellent universality, a series of compounds with well-defined structures were obtained in high yields. Moreover, the obtained compounds showed concentration-enhanced and excitation-dependent emission characteristics. The compounds also exhibited dramatical chemical structure-dependent and aggregation-induced red-shifted fluorescence properties, based on which we successfully obtained red-emitting NTSOLs by simply adjusting chemical structure and concentration. Also, the compounds show good cell staining ability, which can be used in cell imaging.