疏水型二氧化硅粒子对泡沫体系稳定性的影响

本文对市售二氧化硅粒子进行疏水改性,分别用改性前和改性后的二氧化硅粒子与十二烷基硫酸钠制备泡沫分散液,探讨了二氧化硅粒子亲、疏水性,粒子浓度,粒子在气/液界面膜上的吸附量以及动态拉伸条件下的液膜稳定性的变化规律。研究结果表明,在搅拌条件下,与改性后粒子相比,改性前粒子对维持泡沫体系的起泡性和稳定性作用较强。泡沫稳定性随二氧化硅粒子质量分数的增加而增大,在粒子浓度为0.05%时达到最大值。在拉伸条件下,改性后粒子对液膜稳定性的增强效果优于改性前粒子的作用。改性后二氧化硅粒子质量分数为0.05%的分散液的液膜拉伸最长。     

基于缝洞型油藏自黏性粒子的制备及其性能

针对油田裂缝尺度不明确的缝洞型储层,采用悬浮聚合法制备聚丙烯酸酯类自黏性树脂,使其包覆丁腈橡胶粒子,制备表面具有黏性的橡胶粒子。研究了聚丙烯酸酯类树脂、丁腈橡胶粒子、包覆型橡胶粒子3种自黏性粒子的性能,比较了3种粒子的高温油溶率、粒子间的黏结性、热稳定性及力学性能。结果表明:聚丙烯酸酯类树脂粒子黏结性最优,机械强度最低;丁腈橡胶粒子热稳定性最优,自黏性最差;包覆型橡胶粒子解决了聚丙烯酸酯类树脂机械强度弱和橡胶粒子黏结性差的问题,最适用于油田裂缝的封堵。     

混合粒子群优化算法及其应用

提出了一种通过改进全局最优位置粒子寻优策略而提高粒子群优化计算效率的混合粒子群优化算法。针对流程工业典型设备的状态跟踪预报等有计算时间限制的优化问题,混合粒子群优化算法在不改变原有粒子群粒子寻优策略的前提下,将粒子群整体已搜寻到的全局最优位置看作一个特殊的粒子,令该粒子执行梯度下降寻优的寻优策略。在粒子群的寻优迭代计算中增加全局最优位置粒子单独的梯度下降寻优过程,从而将粒子群优化算法的全局寻优特性与梯度下降算法的邻域寻优特性相结合,以提高粒子群优化算法的整体寻优效率,进而缩短寻优计算的时间。针对流程工业典型设备的实际应用表明,混合粒子群优化算法能够减少寻优迭代次数,进而缩短优化计算时间。     

纳米科学技术进展和前景（Ⅳ）——兼论在化工新材料（含涂料）领域的应用

团聚－分散、吸附－脱附及纳米尺寸单元材料的烧结问题。纳米粒子表面修饰和包覆的研究目的应有明确的应用背景：制备纳米粒子防止粒子长大和解决团聚问题。包覆后的小粒子可以消除粒子表面的带电效应,防止团聚;在粒子表面形成一个势垒,使纳米粒子在制备烧结过程中（若用无机物包覆）,粒子不易长大;若用有机物包覆可使无机纳米粒子能与有机物润湿,若用有机物包覆可使无机纳米粒子能与有机物润湿,用于对塑料改性可以提高强度、韧性、使用温度、防水性等。     

ACR/纳米SiO2复合粒子的合成及其对PVC的增韧作用

研究了细乳液聚合制备ACR/纳米SiO2复合粒子及其对PVC的增韧作用。对丙烯酸酯单体中的纳米SiO2粒子进行偶联改性,提高了ACR对纳米粒子的包覆率和接枝率,复合粒子与PVC共混后纳米SiO2粒子在PVC基体中的分散性好。复合粒子对PVC的增韧效果明显优于纳米SiO2粒子和未改性ACR共聚物,复合粒子的用量较少时,就可明显提高PVC的冲击强度。     

粒子表面处理对纳米Ag/PMMA复合粒子的影响

纳米银/聚甲基丙烯酸甲酯(Ag/PMMA)复合粒子是一种新型的功能粒子,可以有效利用昂贵金属纳米粒子组元的独特性能,是高表面能金属纳米粒子稳定化的有效途径。在Ag/PMMA复合粒子的制备过程中,纳米Ag粒子表面处理时所用表面活性剂的种类及用量直接影响Ag/PMMA复合粒子的粒径及分布。纳米Ag粒子在超声波场作用下经十二烷基硫酸钠(SDS)处理后,可在纳米Ag粒子表面形成单体和引发剂的富集区,在适当条件下引发以纳米Ag粒子为核心的原位分散聚合反应。本文通过对各影响因素的研究,采用阴离子表面活性剂SDS对纳米Ag粒子进行表面处理,且用量控制在Ag粒子质量的10%～15%范围内,可实现Ag粒子的PMMA有机包覆。     

基于粒子健康度的快速收敛粒子群优化算法

针对现有粒子群优化算法在工程应用中,特别是在粒子维数较高的情况下,很容易发生早熟收敛等缺点,提出了一种基于粒子健康度的快速收敛粒子群优化算法(HPSO)。给出了粒子健康度的概念及计算方法。该算法通过动态监控粒子的健康度指标,对健康度较低的粒子单独进行变异操作。从而可以在保护健康粒子继续搜索最优值的同时,有效“治疗”非健康的早熟粒子,提高了整个粒子群的寻优能力及跳出局部最优值的能力。然后通过大量的标准测试函数对其进行测试,并将其与标准粒子群优化算法(SPSO)、权重递减的粒子群优化算法(WPSO)进行对比。测试结果表明,在粒子维数较高的应用中HPSO算法的收敛速度更快,效率更高。     

POM/EVA/CaCO3复合材料拉伸载荷下界面应力的数值模拟

应用ANSYS软件对聚甲醛(POM)/乙烯-乙酸乙烯共聚物(EVA)/CaC03拉伸过程中界面应力及其分布进行了数值模拟,以考察相邻的EVA粒子与CaCO3粒子之间的相互作用对界面应力及其分布的影响.EVA粒子与CaCO3粒子之间存在明显的应力集中,尤其是CaCO3粒子靠近EVA粒子的一侧；两粒子的最大剪切应力都偏离了...     

综合相分离法制备聚酰胺6粒子的研究

首先采用滴加非溶剂法和冷却降温法分别制备了聚酰胺6（PA6粒子）,结果表明,前者制备的PA6粒子表面结构疏松,但粒子之间分散性好,而后者制备的PA6粒子表面结构致密,但粒子之间分散性差。然后将滴加非溶剂法和冷却降温法相结合,提出了综合相分离法,采用此方法制备的PA6粒子粒径分布较均匀,粒子与粒子之间分散性好,表面仍有孔洞但结构比较致密。     

核壳型粒子改性聚氯乙烯的发展

分别介绍了国内外有关核壳结构粒子增强增韧PVC的研究工作，核壳结构的粒子包括弹性体、有机刚性粒子和无机刚性粒子。     

新型氨基化磁性纳米粒子的合成

通过嫁接方法在包有二氧化硅的纳米CoFe2O4磁粒表面进行氨基化修饰,制备出一种可用于生物医学领域的新型氨基化纳米磁粒,采用TGA-DTA,IR,VSM和Zeta-potential等测定方法,对氨基化和未氨基化的CoFe2O4纳米粒子进行了表征。元素分析结果显示,有0.98 mmol/g的有机分子固定在纳米粒子表面;红外和热分析数据显示,带氨基的有机分子嫁接到磁粒表面的二氧化硅壳层上;Zeta电位数据也显示,带氨基的有机分子嫁接到纳米磁粒表面;样品的磁性参数显示,氨基化纳米磁粒仍具有好的磁学性能。     

纳米CeO2的制备方法研究现状

介绍了固相法、液相法及气相法制备纳米CeO_2材料的工艺过程及原理,分析了纳米CeO_2制备方法的研究现状,并提出了当前纳米CeO_2制备研究中的难点和工业化生产的解决途径。     

Investigation of Transport Properties of Pr Doped Cerium Oxide Nanoparticles as a Solid Electrolyte for IT-SOFC Applications

Pure and Pr doped CeO₂ nanoparticles were synthesized by citrate–nitrate auto combustion method. The XRD patterns of the prepared nanoparticles were found to be polycrystalline nature having cubic fluorite CeO₂ structure. SEM images depicted all the samples exhibited flaky and porous structure with few large aggregates. FT-Raman studies showed the suppression of F_2g peak in Pr doped CeO₂ nanoparticles which indicated the increased oxygen vacancy concentration. UV-DRS spectra revealed the red shifting of absorption edge on Pr doping. The vibrational band assignment of pure and Pr doped CeO₂ nanoparticles were analyzed by FT-IR spectroscopy. PL intensities of doped CeO₂ nanoparticles decreased compared with pure CeO₂ nanoparticles due to the evolution of non-radioactive oxygen vacancies in the structure. The variation of ionic conductivity as a function of temperature was studied using impedance spectroscopy for pure and Pr doped CeO₂ nanoparticles. It was observed that the ionic conductivity of Pr doped CeO₂ nanoparticles increased compared to pure CeO₂ nanoparticles at the intermediate temperature.     

Antibacterial performance of TiO2 ultrafine nanopowder synthesized by a chemical vapor condensation method: Effect of synthesis temperature and precursor vapor concentration

TiO₂ nanoparticles were synthesized using a chemical vapor condensation (CVC) method, and their physicochemical properties were characterized to optimize the synthesis conditions for antibacterial activity. The antibacterial activities of CVC-TiO₂ nanoparticles and commercialized TiO₂ nanoparticles (P25, Deggusa) were investigated according to UV exposure time and amount of photocatalyst. We found that the specific surface area and the crystallinity of CVC-TiO₂ nanoparticles were varied depending on synthesis temperature and precursor vapor concentration. As a result, the CVC-TiO₂ nanoparticles showed a higher specific surface area and better crystallinity than that of P25TiO₂. More importantly, CVC-TiO₂ nanoparticles generated a larger amount of hydroxyl radicals than P25TiO₂. Consequently CVC-TiO₂ nanoparticles were more effective as an antibacterial photocatalyst than P25TiO₂ under irradiation with UV light. Based-on these results, the optimum synthetic conditions of CVC-TiO₂ nanoparticles for bactericidal effect were found.     

Study on the visible-light-induced photokilling effect of nitrogen-doped TiO2 nanoparticles on cancer cells

Nitrogen-doped TiO2 (N-TiO2) nanoparticles were prepared by calcining the anatase TiO2 nanoparticles under ammonia atmosphere. The N-TiO2 showed higher absorbance in the visible region than the pure TiO2. The cytotoxicity and visible-light-induced phototoxicity of the pure- and N-TiO2 were examined for three types of cancer cell lines. No significant cytotoxicity was detected. However, the visible-light-induced photokilling effects on cells were observed. The survival fraction of the cells decreased with the increased incubation concentration of the nanoparticles. The cancer cells incubated with N-TiO2 were killed more effectively than that with the pure TiO2. The reactive oxygen species was found to play an important role on the photokilling effect for cells. Furthermore, the intracellular distributions of N-TiO2 nanoparticles were examined by laser scanning confocal microscopy. The co-localization of N-TiO2 nanoparticles with nuclei or Golgi complexes was observed. The aberrant nuclear morphologies such as micronuclei were detected after the N-TiO2-treated cells were irradiated by the visible light.     

Photocatalytic Preparation of Encapsulated Gold Nanoparticles by Jingle-bell-shaped Cadmium Sulfide–silica Nanoparticles

Gold (Au) nanoparticles were deposited inside silica: (SiO₂) shells containing cadmium sulfide (CdS) nanoparticles through photocatalytic reduction of potassium dicyanogold(I) by CdS. Photocatalytic Au deposition occurred only when core-shell nanoparticles having a void space between the core and shell, i.e., a jingle-bell-shaped structure, were used. These core-shell nanoparticles were prepared by size-selective photoetching of SiO₂ -covered CdS nanoparticles. The size of Au nanoparticles could be controlled by adjustment of the void space in SiO₂-covered CdS. Dissolution of CdS by acid treatment from the Au-deposited jingle-bell nanoparticles did not have any effect on the surface-plasmon absorption by Au. These facts indicate that Au nanoparticles of adjustable size can be prepared in an SiO₂ shell that prevents mutual coalescence of Au nanoparticles but allows permeation of molecules and ions.     

苄基接枝海藻酸衍生物对TiO2纳米粒分散稳定性的影响

以溴化苄为疏水改性剂,采用双分子亲核取代反应(SN2)制得苄基接枝海藻酸衍生物(BAD)。通过动态光散射技术,考察了在不同p H和离子强度下BAD对Ti O_2纳米粒水悬浮液分散稳定性的影响。并采用红外光谱和扫描电镜对BAD/Ti O_2纳米粒复合物的官能团和表面形貌进行了测试。结果表明,通过SN2反应成功地合成了具有胶体性能的BAD。BAD胶束的平均水动力学粒径(dH)大小为423.4 nm,Zeta电位值为-27.4 m V,表现出较好的胶体性能。在不同p H下,BAD的吸附可提高Ti O_2纳米粒的带电性,使其Zeta电位均低于-30 m V,而且其dH相比单一的Ti O_2纳米粒显著减小。在不同离子强度下,BAD可明显削弱反离子对Ti O_2纳米粒静电屏蔽作用的影响,使Ti O_2纳米粒的团聚行为大大降低,dH显著减小。BAD分子链不仅能够提高Ti O_2颗粒间的静电斥力,而且还能提供有效的空间位阻,提高Ti O_2纳米粒在不同p H和离子强度下的分散稳定性。红外和扫描电镜分析结果表明,BAD和Ti O_2纳米粒主要通过氢键作用来实现BAD在Ti O_2纳米颗粒上的吸附,从而提高Ti O_2纳米颗粒间的空间位阻作用使其稳定分散。     

SCL@SiO2纳米颗粒制备及其稳定Pickering乳液的研究

用共轭亚油酸钠（SCL）在SiO2纳米颗粒表面吸附,得到表面改性的SiO2纳米颗粒,然后在80 oC条件下通过热聚合引发SCL分子自交联,从而稳定SCL@SiO2纳米颗粒的SCL层并改善表面润湿性。通过Zeta电位表征手段证实SCL吸附在SiO2纳米颗粒表面。以SCL@SiO2纳米颗粒作为单一乳化剂制备液体石蜡的Pickering乳液,结果表明该Pickering乳液比传统乳液更稳定。由于SCL@SiO2纳米颗粒的SCL层比简单吸附脂肪酸的SiO2改性颗粒更稳定,且粒径会随着pH的变化而发生变化,因此由其稳定的Pickering乳液具有一定的pH响应性。     

纳米锌铁氧体研究现状及发展前景

简要介绍了纳米锌铁氧体（ZnFe2O4）的研究现状。详细分析了目前国内外纳米锌铁氧体的主要制备方法及研究进展,比较了各种制备方法的优缺点。结合相关行业的发展,指出纳米锌铁氧体今后的研究方向及发展前景。     

共沉淀法合成小粒径单分散Fe3O4纳米颗粒

研究以FeSO4·7H2O和FeCl3·6H2O为原料,NH3·H2O作为沉淀剂,采用共沉淀法制备纳米Fe3O4颗粒,利用IR（红外光谱）、XRD（X射线衍射）等表征手段对割得的纳米颗粒进行了表征。结果表明：制备的纳米Fe3O4粒子粒径较细,且粒径分布较窄。据此找出制备纳米Fe3O4粒子的最佳实验条件为：铁盐溶液浓度为0．5mol／L,沉淀剂溶液浓度为0．2mol／L,Fe^2＋：Fe^3＋：OH^-=1．00：1．00：6．00,反应温度为30℃。制备纳米Fe3O4粒子粒径在10-20mm,且分散性较好;通过XRD谱图可以得出产物为具有立方晶系的纳米Fe3O4粒子。