时间分辨脉冲光声量热法及其应用

光声量热法是一种研究快速光化学反应的新方法，已广泛应用于有机和有机金属化学中涉及自由基中间体以及生物体系中光诱导化学反应生成亚稳态物质的动力学和热力学性质的研究。本文介绍了光声量热的基本原理、实验装置和它在化学、生物体系中的应用。     

光声位相理论及其在化学中的应用研究进展

光声位相作为光声光谱重要的一部分, 包含着很多有价值的信息, 对它的研究可以获得其它光谱甚至光声振幅谱都不能得到的信息。光声位相在测定样品的光学和热学性质、样品无辐射弛豫过程的研究以及深度剖面分析等方面显示了特有的能力。本文结合本实验室近几年的工作, 在光声光谱理论的基础上,对光声位相理论及其在化学中的应用作一综述。     

双联光声传感器和差分池在液体光声检测中的应用

利用双联传感器得到光声信号的叠加作用,可提高光声检测灵敏度或扣除溶液背景吸收。以亚硝基R盐测定钴为例,得到最低检测浓度为0.3ng/mL,相当于4.25×10~(-5)的吸收。     

透明质酸纳米材料在荧光/光声成像和光疗中的应用

荧光/光声成像和光疗技术的生物医学应用引起了人们越来越多的关注, 然而很多荧光/光声造影剂存在生物相容性较差, 缺乏肿瘤靶向性, 信噪比较低, 功能单一等共性问题, 严重限制其诊疗应用. 透明质酸具有优异的生物相容性和主动肿瘤靶向性, 可被透明质酸酶降解, 并且易于化学修饰和实现多种超分子弱相互作用力协同工作. 因此, 人们将透明质酸与荧光/光声造影剂结合制备纳米材料, 使其在细胞乃至活体的标记性能和治疗效果获得了很大的改善. 本文综述了将两类物质结合制备纳米材料的方法, 着重阐述了纳米材料的结构与性能关系, 为其未来设计和开发提供了指导, 最后对存在的主要问题以及未来的重要研究方向进行了分析和展望.     

石英毛细管液相色谱光声检测器

激光诱导光声检测具有灵敏度高,样品适用范围广等优点,将其与HPLC分离技术相结合,有可能成为一种高效分离和高灵敏检测的新分析方法。 我们曾研制了可用于HPLC流出组分检测的石英毛细管流动光声池和传感器。本文进一步报道该光声池在多核芳烃混合物色谱检测中的应用。     

色谱中的光声光谱检测

光声光谱是本世纪七十年代初期重新兴起的高灵敏度光谱分析新技术。它适用于透明、不透明,甚至强散射样品在紫外,可见,红外光区的光热性质研究,已在物理、化学、工程材料、生物、医学等领域得到广泛的应用。 光声光谱(简称PAS)是一种光热吸收光谱,当用一束调制后的(或脉冲的)单色光照射样品时,样品吸收以后,以无辐射弛豫方式将吸收的光能部分或全部地转换成热,样品受热体积膨胀,产生以光源为中心向外扩展的压力波,用置于其中的声传感器便可接收到光声信号。用波长扫描方法得到样品的光声图谱可做定性分析。根据光声信号大小与物质吸光度成正比的关系进行定量分     

固态光聚合反应研究进展

光引发的固态聚合反应一直是令人感兴趣的研究领域.本文综述了固态光聚合的研究进展.着重介绍了双炔类体系,二烯类体系以及(甲基)丙烯酸酯体系的固态光聚合的研究工作以及应用前景.     

光聚合引发剂研究进展

对最近几年光敏聚合引发体系的研究进展进行了评述，并就一些新型光敏引发体系及引发机理进行了介绍。     

固态Nd化合物f-f跃迁的光声光谱研究

通过光声光谱对固态 Nd化合物的 f -f跃迁进行了研究。根据 Nd F3、Nd(sal) 3· H2 O和 Nd(sal) 3(phen) 2 的谱峰位置 ,计算了它们的电子云重排参数β、键合参数 b1/2 和 Sinha共价参数δ,表明三元配合物中钕离子形成键的共价程度最高 ,而 Nd F3中键的共价性最弱。通过光声支量表征了不同化合物中 Nd3+ 的 f -f跃迁光声强度的变化 ,证实了随着键的共价程度增加和配位数的增大 ,超灵敏跃迁强度显著增大     

光声光谱法及其在稀土配合物研究中的应用

结合光声光谱法的基本原理和特点，介绍了光声光谱法在稀土配合物研究中的应用     

Spectrophotometric determination of pentaerythritol tetranitrate (PETN) in waste water from lead styphnate primer plants

An accurate spectrophotometric method is proposed for the determination of pentaerythritol tetranitrate (PETN) in waste water from lead styphnate primer plants by use of phenoldisulphonic acid. The waste water is filtered through a sintered glass crucible and the PETN is determined in the filtrate and the residue. In the determination of PETN in the filtrate, sodium hydroxide is added and the PETN is extracted with methylene chloride (in alkaline solution, styphnate and TNT are not extracted). The methylene chloride solution is then evaporated to dryness, the residue is treated with a solution of phenoldisulphonic acid in sulphuric acid, water and ammonia are added, and the yellow colour is measured. In the determination of PETN in the residue, the PETN is dissolved in acetone, an aliquot of the acetone solution is treated with water and sodium hydroxide, the PETN is extracted with methylene chloride and the colour is developed as above. Various factors affecting the determination were investigated. The solubility of PETN in water was studied.     

冶金炉料中二氧化硅和碳化硅的联合测定

提出冶金炉料中二氧化硅及碳化硅的联合测定方法，硝酸－氢氟酸－盐酸溶解二氧化硅，用硅氟酸钾容量法测定，残渣经焦硫酸钾溶解杂质，不溶碳化硅以重量法测定，经试样全分析及精密度考证，方法简便、可靠．     

山东省主栽果树生殖器官中稀土与微量营养元素的相关性研究

通过对山东省5大类主栽果树20余个树种的花粉、种子和果实稀土与微量元素自然含量进行分析比较, 认为稀土(RE)与微量元素在各树种花粉中平均含量顺序为Fe＞Zn＞B＞Cu＞Mn＞RE, 种子中B＞Fe＞Zn＞Mn＞Cu＞RE, 果实中Fe＞B＞Zn＞Cu＞Mn＞RE. 各元素在各生殖器官中的自然分布因树种而有很大差异. 但基本规律类同, 即花粉＞种子＞果实. 花粉富集各种微量营养元素的能力都很强. 花粉和果实稀土与微量元素之间绝大多数呈正相关, 种子大多呈负相关, 但相关性均不显著.     

Recombination of ions of a dense ion plasma in a fluorine atmosphere

A new effect leading to the slowing of recombination in a weakly nonideal ion plasma is considered. The solvation of ions is included in the explanation of the results from studying a gas discharge afterglow in a fluorine atmosphere. It is shown that recombination in such a system is slowed in comparison to the standard relationships for ideal plasma. The formation and composition of cluster ions in such a medium are considered. The relationship between the variation in the kinetics of recombination and the course of the process according to a complicated mechanism with the intermediate formation of metastable cluster pairs is established. A quantitative model is built and a formula allowing us to describe the recombination rate over a wide range of parameters of the medium is obtained. It is shown that the proposed model is in good agreement with the experimental data.     

蟹,虾壳微观形貌与结构研究

用Ｘ射线衍射与扫描电镜研究了蟹壳，虾壳的形貌与微观结构，蟹壳中以方解石晶型存在的碳酸钙分布在网状结构的有机质中，网孔的尺寸约５～２５μｍ有机基质脱去蛋白后留下的甲壳质呈片层状结构，它的重复距离为０．９６ｎｍ。     

Spectrophotometric determination of bismuth in copper and cartridge brass by the iodide method

An improved spectrophotometric method is proposed for the determination with iodide of trace amounts of bismuth in copper and cartridge brass. The sample is dissolved in nitric acid and the bismuth is separated from the copper by an ammoniacal precipitation in the presence of iron(III) hydroxide as a gathering agent. The hydroxide precipitate is dissolved in hydrochloric acid, sulfuric acid is added, the solution is evaporated to a few ml, hydrobromic acid is added to volatilize the antimony and tin, and the solution is evaporated to fumes of sulfuric acid. The bismuth iodide color is then developed with a composite potassium iodide—sodium hypophosphite reagent. Factors affecting the bismuth iodide color are investigated.     

Development and validation of a gas chromatography/mass spectrometry procedure for confirmation of para-toluenesulfonamide in edible fish fillet tissue

Chloramine-T is a disinfectant being developed as a treatment for bacterial gill disease in cultured fish. As part of the drug approval process, a method is required for the confirmation of chloramine-T residues in edible fish tissue. The marker residue that will be used to determine the depletion of chloramine-T residues from the edible tissue of treated fish is para-toluenesulfonamide (p-TSA), a metabolite of chloramine-T. The development and validation of a procedure for the confirmation of p-TSA is described. Homogenized fish tissue is dried by mixing with anhydrous sodium sulfate, and the mixture is extracted with methylene chloride. The extract is passed through a silica gel solid-phase extraction column, from which p-TSA is subsequently eluted with acetonitrile. The acetonitrile extract is evaporated, and the oily residue is dissolved in hexane. The hexane solution is shaken with fresh acetonitrile. The acetonitrile solution is evaporated and the residue is redissolved in dilute potassium hydroxide solution. The aqueous solution is extracted with methylene chloride to further remove more of the fat co-extractive. The aqueous solution is reacted with pentafluorobenzyl bromide in presence of tetrabutylammonium hydrogensulfate. The resulting di-(pentafluorobenzyl) derivative of p-TSA is analyzed by gas chromatography/mass spectrometry. This method permits the confirmation of p-TSA in edible fish tissue at 20 ppb.     

A non-linear equilibrium analysis of blowdown policy in pressure—swing—adsorption separation

Using the local non-linear equilibrium approach, we investigated pressure—swing—adsorption (PSA) cycles directed toward the removal of an adsorbable impurity present in large amounts in an inert substance. Three blowdown policies are compared (the blowdown is the part of the PSA cycle in which the pressure of a column is released by rejecting gas). In one such policy, the gas resulting from blowdown is rich in the impurity and is rejected as waste. In a second policy in contrast, the production is adjusted so that the blowdown gas is pure and is considered as a product or is reused to recompress or purge another column. The third policy is intermediate, in the sense that part of the blowdown gas is pure and recovered, and part is impure and rejected.The equilibrium approach presented neglects mass-transfer and dispersion effects, but accounts for non-linear equilibria and variations in gas velocity. It thus allows analytical or semi-analytical expressions to be obtained for quantities such as the inert recovery ratio, and hence an easy qualitative discussion of the effects of operating parameters on the recovery. It is shown that the intermediate policy (partial recovery of the blowdown gas) is optimal. The adsorption of methane and ethane on activated carbon from helium or hydrogen are presented as illustrations.     

PP2A in the regulation of cell motility and invasion

Cell motility is a very critical phenomenon that plays an important role in the development of eukaryotic organisms. One of the well studied cell motility phenomena is chemotaxis, which is described as a directional movement of cell in response to changes in external chemotactic gradient. Numerous studies conducted both in unicellular organism and in mammalian cells have demonstrated the importance of phosphatidylionositol-3 kinase (PI3K) in this process. In addition, it is now well established that although PI3K plays an activation role in chemotaxis, the role of phosphatases is also critical to maintain this dynamic cyclical process. Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase that is a key player in regulating PI3K signaling. PP2A is abundantly and ubiquitously expressed and has been highly conserved during the evolution of eukaryotes. PP2A is composed of three protein subunits, A, B, and C. Subunit 'A' is a 60-65 kDa structural component, 'C' is a 36-38 kDa catalytic subunit, and 'B' is a 54-130 kDa regulatory subunit. The core complex of PP2A is comprised of the A and C subunits, which are tightly associated and this dimeric core complexes with the regulatory B subunit. The B subunit determines the substrate specificity as well as the spatial and temporal functions of PP2A. PP2A plays an important role in regulating multiple signal transduction pathways, including cell-cycle regulation, cell-growth and development, cytoskeleton dynamics, and cell motility. This review focuses on the role of PP2A in regulating motility of normal and transformed cells.     

Bimolecular reaction of 2,4,6-tri-tert-butylphenoxyl with hydroperoxide group in a solid polymer matrix

2,4,6-Tri-tert-butylphenoxyl (TBP) is dissolved and reacted with hydroperoxide groups of polyethylene and polypropylene in the amorphous phase. The reaction is not limited by diffusion, and unlike the case in the liquid phase, the concentration of TBP is not zero at the end of the reaction time, even though hydroperoxide groups are in excess. The biomolecular rate constant is smaller in the solid than it is in the liquid phase and depends on molecular motion. A linear relationship between the rate constant and frequency of rotation of radicals in polymers is observed.