Effect of Anion Surface Active Agent on the Preparation of SrTiO_3 Nano-Crystals

SrTiO_3 nano-crystal samples with floccule or flake crystal morphology,which were indexed as a perovskite-type crystal structure based on the results of XRD and TEM,were successfully prepared by one-step liquid reaction method.And the growth mechanism of the SrTiO_3 nano-crystals under the liquid condition with/without adding the surface active agent was investigated.It was found that adding the surface active agent contributes to the processing in which the ions gathering bodies transit to a more stable phase through the chemical reaction and form the flake SrTiO_3 nano-crystals.

New Nano Polymer Materials for Composite Exterior-Wall Coatings

A triethylenetetramine epoxy mixture was synthesized through the reaction of a low-molecular-weight liquid epoxy resin with triethylenetetramine(TETA).Then triethyltetramine(TETA)was injected dropwise into a pro-pylene glycol methyl ether(PM)solution for chain extension reaction.A hydrophilic andflexible polyether seg-ment was introduced into the hardener molecule.The effects of TETA/DGEPG,reaction temperature and reaction time on the epoxy conversion of polyethylene glycol diglycidyl ether(DGEPG)were studied.In addition,several alternate strategies to add epoxy resin to the high-speed dispersion machine and synthesize MEA DGEBA adduct(without catalyst and with bisphenol A diglycidyl ether epoxy resin)were compared.It was found that the higher the molecular weight of triethylenetetramine,the longer the chain segment of the surface active molecule.When the equivalence ratio of amine hydrogen and epoxy group is low,the stability of lotion is good.When the ratio of amine hydrogen to epoxy group is large,the content of triethylenetetramine is small.The main objective of this study is the provision of new data and knowledge for the development of new materials in the coating and electronic industry.

Effects of reinforced nanofluid with nanoparticles on cutting tool wear morphology

Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported on factors governing tool life in machining superalloys,no study was found on the effect of nanoparticles stability on nanofluid performance and consequently resulted tool wear morphologies.In the present work,the nanoparticles were reinforced by means of improving the stability of the base fluid.To that accomplished,the surface active agent (surfactant) was added to the base cutting fluid as a reinforcing element.The effects of new lubricant on the tool wear morphology of A286 works parts were assessed.

Agglomeration Control of Ultrafine Y_2O_3-ZrO_2 and (MgO, Y_2O_3)-ZrO_2 Powders Synthesized by Coprecipitation Process

Chemical coprecipitation was used to produce ultrafine and easily sinterable Y2O3-stabilized and （Y2O3,MgO）-stabilized ZrO2 powders. Six precipitation processes for preparation of ZrO2-based ultrafine powders were designed separately, meanwhile different techniques used to control the agglomeration formation were proposed. By means of TEM, SEM, Raman spectroscopy and IR spectroscopy, the mechanisms of agglomeration control in the precipitation processes and post-precipitation and drying process were investigated. The experimental results show that adding appropriate anion surface active agents （such as PAA1460） or polymer （PEG1540 matching with PEG200） in aqueous solution systems during precipitation processes could reinforce charge effect and location effect for gel particles interface. Adding wetting agents to wet gels washing with distilled water during drying process could change interface structure of gel particles and decrease surface tension between gel particles. The agglomeration control in the precipitation, post-precipitation and drying processes had remarkable influence on the characteristics of powders. By adding various macromolecules in the processes, the agglomeration state could be controlled efficiently, and the characteristics of powders were improved.

Extraction of copper ions by supercritical carbon dioxide

Complexation combined with supercritical fluid extraction was used to extract Cu2+ in this study. The effects of pressure, temperature, volume of CO2 on the efficiency of extraction were systematically investigated. At the optimum condition a 57.32% recovery was achieved. Addition of suitable amount of methanol (v/v = 5%) to the supercritical CO2 can increase in the extraction of Cu2+ (72.69%, RSD = 2.12%, n = 3). And the recovery can further increase in the presence of non-ionic surfactant Triton X-100 because of its function of solubilization. Surfactant was first used in the extraction of metal ions in the present study, and the results are satisfied (90.52%, RSD = 2.20%, n = 3).

Preparation of nanometer complex oxide of Ce_xZr_(1-x)O_2 by mechanically activated solid state chemical reaction

Nanometer cerium-zirconium oxide solution Ce1-x ZrxO2 was synthesized by mechanically activated solid state re- action at middle-low temperatures, with Ce2（CO3）3, ZrOCl2-SH2O and H2C2O4·2H2O as raw materials. The crystal structure and microstructure of the nanometer Ce1-x Zrx O2 were studied with X-ray diffractometry （XRD） and transmission electron microscope （TEM）. The results show that the product is single-cubic-phase solid solution with an average crystal size 19.64 nm. In this article, the influence of surface active agent is also evaluated. Mechanically activated solid state reaction for the preparation of Ce1-xZrxO2 is a new technique of green chemistry without solvent and waste.

Optical property of nanocomposite of mesoporous silica thin films incorporated with gold nanoparticles

Amino-functionalized mesoporous silica thin films （MTFs） are produced using surface active agent F127,and then gold nanoparticles are introduced into the pore channels to prepare the Au/SiO 2 nanocomposite.After assembling the gold,the amino-functionalized MTF undergoes some shrinkage but remains a periodic structure as demonstrated by X-ray diffraction （XRD） patterns.The nanocomposite shows an acute characteristic diffraction peak assigned to （111） plane of the face-centered-cubic structure of gold,indicating that gold nanoparticles crystallize well and grow in a preferred orientation in the pore channels.The surface plasma resonance （SPR） absorption peak near 570 nm undergoes a red-shift accompanied by a strengthening of intensity when HAuCl 4 is used to react with the amino groups on the internal pore surfaces for 4,6,and 8 h.The simulative results are consistent with the experimental ones shows that the absorption property of the Au/SiO 2 nanocomposite is influenced by the dipping time,which affects the size and volume fraction of embedded gold nanoparticles.

Structure and photoluminescence properties of fishbone-like PbMoO_4 nanostructures obtained via the surfactant-assisted hydrothermal method

Fishbone-like PbMoO4 nanostructures are successfully obtained via the surfactant-assisted hydrothermal method at 160 ℃. Polyethylene glycol （PEG2000） is used as the template agent. The nanostructures are characterized via X-ray diffraction, field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible light （UV-Vis） spectroscopy, and photoluminescence （PL） measurements. The PbMoO4 morphology is highly associated with the molecular nature of PEG2000. PbMoO4 nanoparticles obtained from PEG2000 have a fishbone-shaped, scheelite-type tetragonal structure, in which numerous secondary branches vertically grow on both sides of the main stem. The structures exhibit broad PL emission bands with the maximum at 306 and 390 nm when excited at 250 nm. In addition, the UV-Vis absorption edge of the structures is in the 280 to 310 nm region, and the band gap is 4.07 eV. A plausible formation mechanism for the fishbone-like PbMoO4 nanostructures is also discussed.

On Diffuse Interface Modeling and Simulation of Surfactants in Two-Phase Fluid Flow

An existing phase-fieldmodel of two immiscible fluids with a single soluble surfactant present is discussed in detail.We analyze the well-posedness of the model and provide strong evidence that it is mathematically ill-posed for a large set of physically relevant parameters.As a consequence,critical modifications to the model are suggested that substantially increase the domain of validity.Carefully designed numerical simulations offer informative demonstrations as to the sharpness of our theoretical results and the qualities of the physical model.A fully coupled hydrodynamic test-case demonstrates the potential to capture also non-trivial effects on the overall flow.