石蜡微胶囊的制备

针对太阳能利用以及一些蓄热场合,通过示差扫描量热法（DSC）选取了合适的石蜡,以脲醛树脂为囊壁,采用原位聚合法制备了石蜡一脲醛树脂微胶囊,拟将此微胶囊添加到上述应用场合的传热流体中,提高传热流体的热容。实验结果表明,乳化剂OP更适合于熔点60℃石蜡微胶囊的制备。     

脲甲醛缩聚物制备电子墨水微胶囊研究

在原位聚合法制备脲甲醛树脂微胶囊的过程中 ,使用水溶性低分子量脲甲醛缩聚物代替传统的脲甲醛预聚体 (一羟甲基脲、二羟甲基脲 )作为反应单体 ,由于脲甲醛缩聚物比后者更容易吸附在分散相液滴表面 ,解决了用原位聚合法制备脲甲醛微胶囊所常有的结块、粘连、表面粗糙、产率低的问题 .研究了低分子量脲甲醛缩聚物水溶液的粘度特征和表面活性及其与胶囊包封率的关系 .使用这种方法制备出了电子墨水微胶囊     

原位聚合法制备厌氧胶固化引发剂微胶囊

采用原位聚合法制备了以脲醛树脂为壁材、过氧化苯甲酰为芯材的厌氧胶固化引发剂微胶囊。研究了乳化剂聚丙烯酸钠、十二烷基苯磺酸钠、阿拉伯树胶、苯乙烯-马来酸酐共聚物的单独使用及阿拉伯树胶与苯乙烯-马来酸酐共聚物的复配组合和其它工艺条件对微胶囊制备的影响;运用FT-IR、TG和SEM等测试技术对微胶囊进行了表征。结果表明,以苯乙烯-马来酸酐共聚物和阿拉伯树胶作为复合乳化剂,反应终点pH值为1.5左右,反应温度70℃,反应时间4 h,搅拌速率1 000 r/m in,可制得分散适中、形貌较好、粒径约为100μm的微胶囊。以实验制备的微胶囊配制成可预涂厌氧胶胶液,性能可以达到国外公司同类产品的技术指标。     

原位聚合法制备鱼藤酮微胶囊

原位聚合法制备;鱼藤酮微胶囊;鱼藤酮;原位聚合法;微胶囊;三聚氰胺甲醛树脂     

生物农药微胶囊壁材料研究

用原位聚合法对生物农药阿维菌素进行包囊,然后制备微胶囊制剂,并对用于该制剂的两种高分子囊壁材料-三聚氰胺甲醛树脂和脲醛树脂的性能进行了研究。结果表明,两种树脂皆为较好的生物农药用微胶囊缓释剂型的囊壁材料,其制备工艺简单,具有良好的稳定性、粒径大小与分布、悬浮性、缓释性等,包封率均达80％以上。其中三聚氰胺甲醛树脂悬浮性较脲醛树脂更好,缓释性更持久。     

热敏显色微胶囊的制备与表征

热敏显色微胶囊是用于传真、条形码系统、医用图像、各种打印等领域的重要材料,它是一种内部含有染料隐色体的球形胶囊。染料隐色体是一种内酯结构的无色染料,在一定条件下,与显色剂发生显色反应。由于染料隐色体的化学惰性不够理想,易受外界因素的干扰,因而在应用中受到一定限制,所以为了克服其存在的不足,常将其微胶囊化。微胶囊的芯壁结构可以将芯材与外界隔离,提高芯材的稳定性,同时保留芯材原有的化学性质。当环境温度在微胶囊的玻璃化温度以上时,由于形成微胶囊壁的物质透过性显著增加,因此显色成分接触而发生显色反应。本文利用界面聚合法,以聚乙烯醇为保护胶体,曲拉通X-100为表面活性剂,聚氨酯为壁材,染料隐色体为芯材,合成了聚氨酯热敏显色微胶囊。研究了三个主要因素对微胶囊的粒径及其分布、表面形貌和热敏显色性能的影响。结果表明,增大保护胶体浓度,提高乳化速度,增加乳化剂用量,微胶囊的平均粒径变小,粒径分布变窄,表面变得光滑而且致密,具有较高的热敏显色密度。利用红外光谱仪确认了微胶囊的结构,在最优条件下,所制备的微胶囊玻璃化温度为131 ℃,并具有良好的热稳定性。     

甲胺基阿维菌素苯甲酸盐微胶囊的制备与表征

以三聚氰胺-甲醛树脂为壁材,采用原位聚合法制备了甲胺基阿维菌素苯甲酸盐微胶囊,研究了三聚氰胺与甲醛的质量比、芯壁比、乳化剂、搅拌速度与时间、pH值、温度等因素对微胶囊形成的影响,对制备的微胶囊进行了表征,测定了甲维盐微胶囊化前后的光解率。结果表明,三聚氰胺与甲醛质量比为1∶2、芯材与壁材质量比为3∶2、以质量分数1%羟乙基纤维素(HEC)为乳化剂、在1000r/min搅拌速度下、pH=5.0和50℃保温2h可制备出形貌较好、平均粒径4.4μm的甲维盐微胶囊。红外光谱分析证明,甲维盐已完全被包覆在微胶囊中。紫外分光光度法测定其缓释性能良好。光解实验表明,微胶囊化可有效降低甲维盐原药的光解。     

不同相对分子质量羟乙基纤维素对甲维盐微胶囊制备的影响

采用原位聚合法以三聚氰胺-甲醛树脂为壁材制备了甲维盐微胶囊。 探讨了不同黏均相对分子质量羟乙基纤维素作为乳化剂对微胶囊表面形貌、粒径及其分布、包覆率与载药量的影响,对使用不同黏均相对分子质量羟乙基纤维素作为乳化剂制备的微胶囊的释放性能进行了表征。 结果表明,以相对分子质量较小的羟乙基纤维素制备的微胶囊外形规则、致密且无黏连现象。 随羟乙基纤维素黏均相对分子质量的增加所得微胶囊的平均粒径及粒径分布逐渐增大,包覆率与载药量逐渐减小。 释放性能的研究表明,采用相对分子质量较小的羟乙基纤维素制备的微胶囊的释放性能较好。     

微胶囊化石蜡的制备和热性能

微胶囊化石蜡的制备和热性能;微胶囊;原位聚合法;相变材料;差示扫描量热法     

主链含酪氨酸磷酸酯药物控制释放材料的研究

采用溶液缩聚方法制备了含酪酸烷基酯的聚磷酸酯，研究了聚合物对氨甲蝶呤的体外释放性能和聚合物包裹氨甲蝶呤微胶囊的制备方法及其释药性能。     

Review of Analytical Methods for Atmospheric Oxidants Measurements

Abstract

Instrumental and manual methods currently available for the measurement of atmospheric oxidants are surveyed. Techniques used in the United States are emphasized and their advantages and disadvantages are discussed. Commercial systems are evaluated in terms of general operating principles rather than of specific instruments. The ability of these techniques to meet the measurement requirements defined by U.S. Federal air quality oxidant criteria are discussed. Alternative chemical techniques that may have some advantages over the neutral, buffered KI procedure are discussed. Also some attractive, alternative instrumental procedures that are ozone-specific are presented. These systems are based on chemiluminescence and ultraviolet absorption photometry. Electrochemical and colorimetric methods for total oxidant measurements are compared. Finally, some data are presented on relationships of ozone and total oxidants.     

A study of mica structure and strength properties of polymer materials based on it

The mica microstructure is studied, and its shape and particle sizes are found as dependent on coating technology. Using epoxy and organosilicon polymers, several lots of materials with different contents of mica are prepared and mechanical tests are performed. The optimal amounts of mica wherein the initial strength characteristics are preserved are found. The thicknesses of epoxy and organosilicon polymer wherein high optical decorative properties of mica are preserved are determined.     

On topological and geometrical distance matrices

Differences between topological and geometrical distance matrices are examined. Some examples of geometrical distances when graphs are embedded in spaces of different dimensions are given. Relations of topological distance matrices to other graph matrices are shown. The topological distance matrices are defined in the Hilbert space and their elements are distances through the graph lattices.     

Densities,speeds of sound,excess volumes and viscosities of binary mixtures of mtbe with tetralin and decalin at 303.15 k

Measurements of densities, speeds of sound, excess volumes and viscosities of binary mixture of methyl tert-butyl ether with tetralin and decalin are reported at 303.15?K over the entire range of composition. Excess volumes are measured using batch dilatometer technique. Sound speeds are obtained using ultrasonic interferometer. Densities are computed from excess volume data. Isentropic compressibilities are derived from density and sound speed data. Speeds of sound are evaluated on the basis of Jacobson's free length theory and Schaff's collision factor theory. The predicted values are in good agreement with the experimental results. The viscosity data are analysed on the basis of corresponding states approach. Excess volumes and deviation in isentropic compressibilities are negative and deviation in viscosities are positive over the entire composition range. The experimental results are discussed in terms of possible molecular interactions between unlike molecules.     

Fluorescence imaging and point measurements of tissue: applications to the demarcation of malignant tumors and atherosclerotic lesions from normal tissue

The possibilities of using laser-induced fluorescence for tissue diagnostics are discussed. The tissue types investigated are malignant tumors and atherosclerotic lesions. Studies with natural autofluorescence as well as with fluorescent tumor markers are included in this paper. Fluorescence emission and decay data are presented for some tissue chromophores contributing to tissue autofluorescence. Optical spectroscopic characteristics of fluorescent malignant tumor markers are analyzed and instrumental designs for clinical applications are discussed. Images recorded with a multicolor fluorescence imaging system developed in Lund are presented.     

若干含多硫基的配合物的合成方法及结构特征

本文综述了近年来我们合成的十二种多硫基的配合物，这些配合物含有Ｓ＾２－２，Ｓ＾２－４，Ｓ＾２－５，Ｓ＾２－６，Ｓ＾２－７等多硫革配体，总结了这些配合物中的金属配位构型，比较了各种多硫基的Ｓ－Ｓ键长及有关键角，归纳了配合物外光谱，并阐述了其中几个配合物与ＮＨ２ＮＨ２的反应性能。     

Studies in atomic-fluorescence spectroscopy-IV The atomic-fluorescence spectroscopic determination of selenium and tellurium

Selenium and tellurium are determined down to 0.25 and 0.12 p pm respectively by measuring the atomic-fluorescence signals at 2040 A and 2143 A respectively. Other possible wavelengths of measurement are considered in detail and the effects of some extraneous ions are examined. Microwave-excited electrodeless discharge tubes are used as spectral sources and intensity measurements are made with a Unicam SP 900A atomic-absorption/flame-emission spectrophotometer. Atomic-absorption measurements are also made with the same sources and spectrophotometer. The advantages of atomic-fluorescence methods and the use of electrodeless discharge tubes are discussed.     

A perturbative calculation of the rovibrational energy levels of methane

The rovibrational energy levels of methane are determined from a quartic ab initio potential energy force field where the expansion coordinates are the Morse coordinates for the stretches and extension coordinates for the bends. Energies are calculated using canonical Van Vleck perturbation theory. Results are obtained for both rotation-vibration Hamiltonians expressed as functions of curvilinear and rectilinear normal coordinates. Second, fourth, and sixth order curvilinear results are compared with experimental results, and fourth order results for the rectilinear and curvilinear Hamiltonian are compared to each other. The calculated rovibrational levels are in good agreement with the experimental values for low J levels. The calculated rotational level splittings are in even better agreement with the experiment. In particular, the ground state tetrahedral splittings, which are as small as 10(-4) cm(-1), are well reproduced by our calculations at sixth order.     

Spot-test detection of aryl hydrazines, hydrazones, osazones, oximes and aromatic amines

Arylhydrazines are detected by oxidation with N-bromosuccinimide and coupling with resorcinol to form azo-dyes which are intensely coloured in alkaline media. Hydrazones and osazones are hydrolysed to form the arylhydrazines, which are then tested for 4-Nitro- and 2,4-dinitrophenylhydrazines are tested for by forming their hydrazone with salicylaldehyde and adding alkali to produce a violet colour. The hydroxylamine formed by the hydrolysis of oximes is oxidized by iodine monochloride in the presence of sulphanilic acid; coupling with 8-hydroxyquinoline forms a dye that is red in alkali. Intense colours are immediately produced when primary, secondary and tertiary aromatic amines are mixed with diacetoxyiodobenzene. All the tests are sensitive and appear to be specific.     

Contactless conductivity detection for microfluidics: designs and applications

Different methods for construction of contactless conductivity detectors (CCD) for microchip electrophoresis device are described in this review. This includes three main schemes of CCD for microchips, such as (i) the detection electrodes are placed along the microchannel from outside of the microchip and they are insulated from the channel by the cover lid of microchip device; (ii) the electrodes are placed across of the microchannel in the same plane and they are insulated by thin separation channel walls and (iii) electrodes are buried in widened part of microchannel and they are insulated from solution by ultrathin layer of silicon carbide. Specific issues related to the CCD on microfluidics are discussed, such as an influence of shape and magnitude of ac voltage and placement of electrodes and their insulation. Various applications for security, pharmacological, bioassays and food analysis purposes are described.