Rapid communication Preparation of TiO_2 nanometer thin films with high photocatalytic activity by reverse micellar method

Two kinds of TiO_2 nanometer thin films were prepared on stainless steel bythe reverse micellar and sol-gel methods, respectively. The calcined TiO_ 2 thin films werecharacterized by X-ray diffraction (XRD), atomic force microscopy (AFM), BET surface area and X-rayphotoelectron spectroscopy (XPS). Photocatalytic activity was evaluated by photocatalyticdecoloration of methyl orange aqueous solution. The results showed that the TiO_2 thin filmsprepared by reverse micellar method (designated as RM-TiO_2 films) showed higher photocatalyticactivity than those by sol-gel method (designated as SG-TiO_2 films). This is attributed to the factthat the former is composed of smaller monodispersed spherical particles with a size of about 15 nmand possesses higher surface areas.

Formation regularity of phases in nanometer powders of Al-Fe alloy prepared by gas evaporation

Nanometer powders of Al Fe alloy were prepared by gas evaporation. The formation regularity of the phases in the as prepared powders and the morphology of the particles were examined. The experimental results show that chemical composition of the master alloy is the key factor which controls the chemical composition of the compound phases in nanometer powders at given evaporating temperature, the compound phases with high Fe mole fraction will form with increasing of Fe content in master alloy. Only Al 13 Fe 4, FeAl 2 and Al 2Fe compound phases form in nanometer powders in present experiment, changing of the pressure of Ar can only alter relative amounts of the compound phases in the powders. Nanometer particles with inhomogeneous tissue were obtained, which is very different from that of pure Al and Fe nanometer particles. When mole fraction of Fe in particles increases, the inhomogeneity is enhanced. [

Tribological performance of nanometer samarium borate

Nanometer crystal samarium borate with a particle size of 20～40?nm was prepared using replacing solvent drying technique. The wear resistance and load carrying capacity of 500SN base oil could be improved and the friction coefficient could be decreased by the addition of nanometer samarium borate. But the dosage of samarium borate nanoparticles had to be controlled at a relatively low level, a higher concentration of nanoparticles was not of beneficial to the tribological performance of the oil. The optimal dosage of nanometer samarium borate is 1.0%. Tribochemical reactions took place in the tribological process, which resulted in the formation of deposition products including diboron trioxide and disamarium trioxide. Fe 2B and FeB were also found on the wear scar. The improvement of tribological properties of the oil comes from the formation of deposition layer and permeating layer. [

Catalysis of Nanometer α-Fe_2O_3 on the Thermal Decomposition of AP

Nanometer α-Fe2O3 catalysts were prepared by hydrolyzation in high temperature. Three kinds of precipitators, NaOH, （NH4）2CO3 and urea were used to compare the effect in the process of hydrolyzation. Nanometer sizer, transmission electron microscopy （TEM） and X-ray diffraction （XRD） were employed to test the profiles and diameters of the product particles. The test results indicate that the production is nanometer α-Fe2O3 with narrow particle size distribution （PSD） and good dispersibility. The catalysts are mixed with ammonia perchlorate （AP） in 1.0 wt.%. And the composite particles of catalysts with AP are prepared using a new solvent-nonsolvent method. Differential thermal analyzer （DTA） is employed to analysis the thermal decomposition of the composite particles and pure AP sample. The results imply that the thermal decomposition curve peaks of the samples in which nanometer α-Fe2O3 catalysts are added appear comparatively more ahead than that of pure AP sample. Among these mixtures added nanometer material, the smaller the particle diameter of catalyst is, the more ahead the thermal decomposition curve peaks of AP appear. The high and low temperature thermal decomposition curve peaks of AP mixed with the catalyst deposed by urea are more ahead of 77.8?℃ and 9.7?℃ than that of pure AP, respectively. The mechanism of the catalyst deposed by urea with smaller diameter and the distinct catalysis of the particles on the thermal decomposition of AP are discussed.

Sonocatalytic degradation of methyl orange in the presence of (nanometer and ordinary) anatase TiO_2 powders

The nanometer and ordinary anatase titanium dioxide(TiO_2) powders were adopted as the sonocatalysts for the degradation of methyl orange used as a model compound for the first time. It was found that the sonocatalytic degradation effect of methyl orange in the presence of TiO_2 powder were much better than that without TiO_2, but the sonocatalytic activity of the nanometer anatase TiO_2 particle was obviously higher than that of ordinary anatase TiO_2 particle. Although there are many factors influencing sonocatalytic degradation of methyl orange, the experimental results showed that the best degradation ratio of methyl orange could be obtained when the experimental conditions were: initial concentration 15 mg/L, nanometer anatase TiO_2 adding amount 750 mg/L, ultrasonic frequency 40 kHz, output power 50 W, pH = 3.0 and temperature 40℃ within 150 min. In addition, the catalytic activity of reused nanometer anatase TiO_2 catalyst was also studied and found to decline gradually comparing with initial nanometer anatase TiO_2 catalyst. All experiments indicated that the method of the sonocatalytic degradation of organic pollutants in the presence of TiO_2 powder was an advisable choice for non- or low-transparent organic wastewaters.

Study on Adsorption Behavior of Rare Earth Complexes on Nanometer-Size Titanium Dioxide with ICP-AES

A new method of using nanometer TiO 2 as solid phase extractant coupled with ICP AES was proposed for speciation of rare earth elements. The adsorption behavior of rare earth complexes on nanometer TiO 2 was investigated. Effect of pH value, contact time, elution solution and interfering ions on the recovery of the rare earth complexes were studied. A quantitative recovery (>90%) was found in the pH range of 4～9.0 for Eu citric, 4.5～9.0 for Eu oxine and Eu HIBA, and 6.5～9.0 for Eu 3+ . Eu EDTA can not be adsorbed in the pH range studied. There is large difference in the adsorption behavior on nanometer TiO 2 between rare earth element and its complexes. The possibility of application of nanometer TiO 2 on the speciation of rare earth element was explored.

Induction of SiHa Cells Apoptosis by Nanometer Realgar Suspension and Its Mechanism

The effects of nanometer realgar uterine cervix cancer cell line SiHa cells and suspension on proliferation and apoptosis of human oncogenic genes HPV16E6/E7 were investigated. A ＂micro-jet effiux＂ strategy was used for the preparation of nanometer realgar suspension. SiHa cells were treated with nanometer Realgar suspension in various concentrations （6.25, 12.5, 25 and 50 mg/L） for different durations （12, 24, 48 and 72 h）. The inhibitive effect of nanometer realgar suspension on growth of SiHa cells was detected by MTT method. Special morphological changes of apoptosis were observed by transmission electron microscopy （TEM） and DNA fragments electrophoresis. The apoptotic rate was quantified by flow cytometry （FCM）. The expression of HPV 16E6/E7 mRNA and protein was assayed by RT-PCR and Western blot respectively. The results showed after being treated with 25--50 mg/L nanometer realgar suspension for 48 h, the survival rate of SiHa cells was decreased, and apoptotic rate markedly increased in a time- and concentration-dependent manner. TEM and DNA electrophoresis revealed the special morphological changes of apoptosis. The apoptotic rate of SiHa cells treated with nanometer realgar suspension was significantly higher than in the control group （P〈0.01）, and G0/G1 phase arrest appeared following treatment with nanometer realgar suspension in 25 and 50 mg/L for 48 h. RT-PCR and Western blot assay indicated that nanometer realgar suspension reduced the HPV16E6/E7 gene expression. Nanometer realgar suspension could inhibit the proliferation and induce apoptosis of SiHa cells. The mechanism may be related to the down-regulation of the HPV16E6/E7 gene expression.

PREPARATION OF NANOMETER ZINC OXIDE BY EVAPORATION METHOD

Nanometer ZnO particles were synthesized by evaporating of zinc powders of averageparticle size of 370μm studied by XRD, TEM and electron diffraction. The particleswere formed by the oxidation of evaporated zinc vapor in the air. It was found that the particles range from 70 to 100nm in average particle size. The effect of experimental parameters was investigated, the increase of the air flow-rates reduced the average particle size, while increasing the evaporation temperature and the amount of metal charged increased the average particle size. TEM of the particles collected showed that the crystal habits of particles have a tetrapod-like of wurtzite structure consists of four needle crystals. It was found by electron diffraction that all particles were single crystal.

Absorption and Photocataly tic Degradation of Machine Oil by Exfoliated Graphite-Supported Nanometer TiO2 Material

By loading nanometer anatase onto exfoliated graphite with the sol-gel method, exfoliated graphite-TiO2 composite （EG-TiO2） can be prepared, which can adsorb oil and can also degrade oil. In a technologic condition for preparing EG-TiO2, the impregnated number of times is the most important factor to influence oil-adsorbing capability, that is, when the impregnated number of times increases, the amount of saturation-adsorbed oil decreases. The study of EG-TiO2 photocatalytic degradation of machine oil based on the weight-loss method and infrared spectrum method indicates that EG-TiO2 has obvious effect of photocatalytic degradation for machine oil. Its performance is superior to pure nanometer TiO2 powder because nanometer TiO2 in EG-TiO2 has three-dimension laminar structure and comparatively high adsorption capability.

PREPARATION OF CAPACITIVE-TYPE CO_2 GASSENSITIVE ELEMENT USING NANOMETER POWDERS

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Development and Evaluation of a New Nanometer Based Spacer NMS-I

In view of the inadequate cementing quality in the cementation for long isolation intervals ofoil and gas wells, and considering the field practice in Tarim Oilfield, a nanometer material LC-212 was introduced as the base stock to experimentally develop a new spacer system NMS-I, in combination with other materials, including a chemical gel plugging agent, carboxymethyl cellulose and barite. Experimental results indicated that the system had a wide adjustable range of density, good rheological property, static stability and compatibility with cement slurry. It also showed no flocculating or thickening effect on the water-base drilling fluid and low-density cement system. Meanwhile, the capacity of lost circulation control and the influence of the spacer on the second interfacial cementing strength were evaluated by a self-made lost circulation simulator and shearing test facility. The results showed that the spacer had favorable plugging and flushing effect, and the second interfacial cementing strength can be greatly improved. Moreover, based on the experiments, the mechanisms of spacer function were analyzed. The results obtained from the investigation offer a novel approach to resolving some practical problems in cementing jobs.

Sonocatalytic Damage of Bovine Serum Albumin (BSA) in the Presence of Nanometer Titanium Dioxide (TiO_2) Catalyst

The sonocatalytic damage of bovine serum albumin （BSA） was studied in the presence of nanometer titanium dioxide （TiO2） powders by low frequency （80 kHz） ultrasound. The destruction of secondary structure and change of α-helical structure of BSA were reflected by ultraviolet （UV） and circular dichroism （CD） spectroscopies.

PREPARATION OF NANOMETER ZrO_2-8% Y_2O_3 POWDERS BY AZEOTROPIC DISTILLATION PROCESSING

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Nanometer Stripe Microstructure of Supersaturated Solid Solution in Fe-Cu Alloy

Strengthening due to precipitation of Cu in the a-Fe matrix is an important phenomenon utilized in the design of HSLA steels. In the present work, the microstructure of supersaturated solid solution in Fe-1.18%Cu binary alloy was investigated by means of high resolution electron microscopy. The results indicated that the solid solution was heterogeneous, there were lots of Cu atom clusters, which consisted of diffractive stripe microstructure similar to twin crystal. Orientation deviation was observed between two （110）o planes in diffractive stripes, which results in light and shade contrast. Furthermore, formation mechanisms of the nanometre stripe microstructure were discussed in terms of the interaction of Cu and Fe atoms in the Fe-Cu binary alloys.

Progress in Research on Nanometer Al_2O_3 Fabricated by Sol-Gel Method

Nanometer Al_2O_3 is one of new types of functional materials with broad application and development prospects in the future. The basic principle and ways of nanometer Al_2O_3 fabricated using sol-gel technique were introduced, and the factors affecting nanometer Al_2O_3 fabricated using sol-gel method were analyzed. The progress in research on nanometer Al_2O_3 and the application fields of nanometer Al_2O_3 were reviewed. The existing problems and the problems prospect for nanometer Al_2O_3 were pointed out.

Synthesis, Characterization, and Electrochemical Property of Nanometer Porphyrin Dimer

A nanometer porphyrin dimer was synthesized with fumaryl chloride as a bridge-linked reagent. The characterization was carried out with elemental analyses, ^1H NMR, UV-Vis, and IR spectrometries, and then the electrochemical properties of the porphyrins were studied. The authors found that there was moderate electronic communication between the two porphyrin rings in the nanometer porphyrin dimer.

PREPARATION OF NANOMETER TiO_2 ORGANIC SOLUTION——EFFECT OF ORGANIC SILOXANE ON SOL PROPERTIES

A homogeneous longtime stabilized transparent nanometer TiO2 organic solution was obtained by means of the simultaneous hydrolysis and co-polycodensation of tetrabutyltitanate (TBT) and methacryloxypropyltrimethoxysilane (MAPTMS) by the sol-gel process. The particle size of nanometer titanium dioxide was controlled by use of bifunctional silanes, such as diphenyldimethoxysilane (DPDMS), diphenyldiethoxysilane (DPDES) and dimethyldiethoxysilane (DMDES). The effect of TiO2 content in the solution on the refractive index of system was discussed in detail. The result shows that the refractive index of solution increases linearly with TiO2 content. The refractive index of the three hybrid nanometer materials attained 1.6053, 1.5846 and 1.5346, respectively. The size of nanometer particles was characterized by TEM and the particle diameter thus obtained is in the range of 20-90 nm. FT-IR spectra of the materials show that the Ti— O—Si bond is formed.

Study on the Properties of Nanometer CeO_2 Doped with Zr^(4+),La^(3+),Pr^(3+)

Different nanometer CeO_2-ZrO_2 mixed oxides doped with lanthanum or praseodymium were prepared by coprecipi-tation. The characteristics of all mixed oxides were tested by XRD, SEM, TEM, and XPS. XRD results showed thatall oxides were formed solid solution with CaF_2 structure at low temperature and had good thermal stability. MoreCe^(4+) ions were rich on the surface by XPS, which were beneficial to oxygen storage. The particle mediun sizes (d_(50))of all oxides powders were approximately 10～20 nm by small angle scattering goniometer. When doped Zr^(4+) inCeO_2, the specific surface areas were improved at low or high temperature. The area of Ce_(0.6)Zr_(0.3)La_(0.04)Pr_(0.06)O_2powder had excess 110 m^2/g after calcining at 923 K for 4 h, even calcined at 1273 K for 4 h, the area was up to65 m^2/g.