Controlled release of urea encapsulated by starch-g-poly(L-lactide)

This paper presented a new approach for preparing a new type of slow-release membrane-encapsulated urea fertilizer with starch-g-PLLA as biodegradable carrier materials. By solution-casting and washing rapidly with water the urea was individually encapsulated within the starch matrix modified by L-lactide through in situ graft-copolymerization.

Synergistic extraction and recovery of Cerium(IV) and Fluorin from sulfuric solutions with Cyanex 923 and di-2-ethylhexyl phosphoric acid

Synergistic extraction and recovery of Cerium(IV) (Ce(IV)) and Fluorin (F) from sulfuric solutions using mixture of Cyanex 923 and di-2-ethylhexyl phosphoric acid (D2EHPA) in n-heptane have been carried out. in order to investigate the synergistic extraction of Cyanex 923 + D2EHPA, extraction Ce(IV), F, Ce(III) and Ce-F mixture solution using D2EHPA or Cyanex 923 as extractant alone were studied firstly, and then Synergistic extraction of Ce(IV), F and Ce(IV)-F mixture solution with D2EHPA + Cyanex 923 were carried out. The largest synergistic coefficient of Ce(IV) is obtained at the mole fraction X-Cyanex (923) = 0.8. The synergistic enhancement coefficients (R-max) obtained for Ce(IV) are 23.12 in Ce(IV) solution, and in Ce-F mixed solution R-max for Ce(IV) and F are 2.24 and 3.25 respectively.

A facile pathway to prepare enzymatically degradable microcapsules with tunable capsule shell properties

Dextran sulfate (DS)/poly-L-lysine (PLL) microcapsules are fabricated by an in situ coacervation method using DS-doped CaCO3 microparticles as templates. Twinned superstructures or spherical CaCO3 microparticles are produced depending on DS concentration in the starting Solution. DS/PLL microcapsules with ellipsoidal or spherical outline are obtained after removal of templates in disodium ethylene diamine tetraacetate dehydrate (EDTA) without PLL. Their shell thickness and negative surface charges increase with the DS weight percentage in the templates. The surface potential of DS/PLL microcapsules.

用于纳米粒子合成的微乳液

微乳液作为纳米反应器的最大优点是可以实现纳米粒子尺寸控制。体系中水的含量、表面活性剂、助表面活性剂等都是控制粒子尺寸的可调因素 ,研究这些因素对所合成的纳米粒子尺寸以及产量的影响对于实际应用有重要的意义。本文评述了近年来相关的研究进展 ,对微乳液法在合成纳米粒子中的应用前景作了展望。

电极用纳米Ag_2O的电化学阻抗行为

用电化学阻抗技术(EIS)对具有不同粒径分布组成的氧化银电极进行了研究。通过建立合理的模拟等效电路,解析了各测试电极间电化学性能的差异。在充放电循环过程中,具有合适配比的混配电极A非法拉第电荷消耗减少,电极的传质传荷性能明显优于传统电极C和纯纳米粒子组成电极F,展示出可逆电极的电化学行为。通过对动电位阻抗谱的解析,发现电极反应经历了4个明显的动力学过程,对不同组成电极的动力学可控程度有了大致了解。

An approach for fabricating self-assembled monolayer of Ag nanoparticles on gold as the SERS-active substrate

In this paper, an approach for fabricating an active surface-enhanced Raman scattering (SERS) substrate is adopted. This approach is based on the assembling of silver nanoparticles film on gold substrate. Rhodamine 6G (R6G) and p-aminothiophenol (P-ATP) were used as probe molecules for SERS experiments, showing that this new active substrate has sensitivity to SERS response. Tapping-mode atomic force microscopy (AFM) was also used to investigate the surface morphology following the fabricating process of the active SERS substrate, which showed that large quantities of silver nanoparticles were uniformly coated on the substrate.

Self-organization of interlaced network lamellar crystals of trans-1,4-polybutadiene (TPBD) on an amorphous surface

A novel morphology of TPBD crystals consisting of a three-dimensional interlaced network was obtained by casting the self-seeded 0.1% benzene solution onto carbon-boated mica. Both the transmission electron microscopy (TEM) and electron diffraction (ED) analyses showed that the network was composed of well-developed lamellae. It is imagined this interesting morphology is the results of asymmetrical growth of the original TPBD lamellae on the amorphous interface, and that their preferred orientation changed when they encountered each other.

Positive- and negative-ion matrix-assisted laser desorption/ionization mass spectrometry of saccharides

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) of oligosaccharides and polysaccharides has been investigated in detail, It is demonstrated that cationized species of oligosaccharides, [M+Na](+) and [M+K](+), are dominant products under the MALDI condition, and negative ions of oligosaccharides are not formed to any significant extent in this process, The molecular masses of polysaccharides are similarly determined by positive- and negative-ion MALDI-MS with the help of column chromatography. The distinction between positive- and negative-ion MALDI mass spectra of oligo-and polysaccharides indicates that the MALDI processes for saccharides vary with molecular mass. The matrix plays a more important role in the ionization process for oligosaccharides, while in the desorption process for polysaccharides. (C) 1998 John Wiley & Sons, Ltd.

高效毛细管电泳安培检测的进展

本文对高效毛细管电泳电化学检测方法中的安培检测进行了评述.安培检测具有灵敏度高、选择性好的特点.安培检测根据毛细管内径的大小有离柱安培检测和柱端安培检测.近年来脉冲安培分析法、化学修饰电极也已被引入毛细管电泳电化学检测.

聚氧化乙烯和聚醋酸乙烯酯共混热力学参数的理论估算

实验测定了聚氧化乙烯（ＰＥＯ）和聚醋酸乙烯酯（ＰＶＡｃ）的共混热以及共混组分的热压系数和热膨胀系数．并由上述实测值计算了状态方程参数．用Ｈａｍａｄａ~［１－２］等改进的Ｆｌｏｒｙ状态方程理论估算了ＰＥＯ／ＰＶＡｃ混体系的交换能参数（Ｘ_１２）、相互作用参数（ｘ_１２／ｒ_１）和剩余混合体积（Ｖ~Ｅ／Ｖ~０）．