Photocatalysed Reduction of Aqueous Sodium Carbonate Using LaCoO_3 Nano Particles

Heterogeneous photocatalysed reduction of aqueous Na_2CO_3 was carried out by using nano LaCoO_3 semiconductor powders. Formic acid and formaldehyde were identified as photoproducts,and were measured spectrophotometrically using Nash reagent. The effect of different parameters such as sodium carbonate concentration,amount of photocatalyst and different light sources on the yield of photoproducts was also investigated. It shows that nano LaCoO_3 has photocatalytic activity. Irradiation leads to the production of electrons in the conduction band of the LaCoO_3 semiconductor. It is likely that the photoproduced electrons initially reduce CO_3 (2-) to HCOO -,and then to HCHO and CH_3OH.

Enhanced thermoelectric performance through homogenously dispersed MnTe nanoparticles in p-type Bi_(0.52)Sb_(1.48)Te_3 nanocomposites

In this work,we report that the thermoelectric properties of Bi（0.52）Sb（1.48）Te3alloy can be enhanced by being composited with Mn Te nano particles（NPs）through a combined ball milling and spark plasma sintering（SPS）process.The addition of Mn Te into the host can synergistically reduce the lattice thermal conductivity by increasing the interface phononscattering between Bi（0.52）Sb（1.48）Te3 and MnTe NPs,and enhance the electrical transport properties by optimizing the hole concentration through partial Mn^2＋ acceptor doping on the Bi^3＋ sites of the host lattice.It is observed that the lattice thermal conductivity decreases with increasing the percentage of Mn Te and milling time in a temperature range from 300 Kto 500 K,which is consistent with the increasing of interfaces.Meanwhile,the bipolar effect is constrained to high temperatures,which results in the figure of merit z T peak shifting toward higher temperature and broadening the z T curves.The engineering z T is obtained to be 20%higher than that of the pristine sample for the 2-mol%Mn Te-added composite at a temperature gradient of 200 K when the cold end temperature is set to be 300 K.This result indicates that the thermoelectric performance of Bi0.52Sb1.48Te3 can be considerably enhanced by being composited with Mn Te NPs.

Effective photodegradation of 4-nitrophenol with CuO nano particles prepared by ionic liquids/water system

The hydrophobic ionic liquids/water two-phase system was developed to prepare CuO nano particles.The catalytic activity of the synthesized CuO was investigated by photodegradation of 4-nitrophenol(4-NP)in the presence of H_(2)O_(2) under visible light irradiation.The optical properties of the synthesized CuO were characterized by ultraviolet–visible(UV–Vis)diffuse reflectance spectroscopy(DRS).Experimental results indicated that the band gap energy(Eg),conduction band edge potential(ECB)and valence band edge potential(EVB)of the synthesized CuO were 1.37 e V,0.625 e V and 1.995 e V,respectively.A degradation efficiency of 4-NP(4.8 mmol L^(-1))as high as 95.3% could be achieved under the conditions of p H 6.0,0.48 g L^(-1)of CuO dosage,1.4% of H_(2)O_(2) dosage and 90 min of degradation time.The synthesized CuO exhibited poor catalytic activity under alkaline conditions due to the disassociation of 4-NP,which elevated the repulsion between CuO and the 4-NP anions.The synthesized CuO nano particles exhibited higher catalytic activity compared with the catalysts reported in literature.Furthermore,the synthesized CuO nano particles could be reused at least six times without decreasing their catalytic activity.Compared with the traditional hydrothermal method,mild operating conditions and time saving are the advantages of the developed method for the preparation of CuO.

The Study of Structural and Magnetic Properties of NiO Nanoparticles

Nickel Oxide (NiO) is an important transition metal oxide with cubic lattice structure. Among the magnetic nanoparticles, fabrication of nickel nanoparticles is often more difficult than that of the other particles. This is because they are easily oxidized. To achieve pure nickel nanocrystals, numerous methods have been conducted in organic environments in order to prevent formation of hydroxide or oxidation. In the present work, we report the synthesis of NiO nanoparticles. Magnetic properties of NiO nanoparticles with different sizes and at different temperatures are compared. The phase structures, particle sizes and magnetic properties of NiO nanoparticles have been characterized by X-ray diffraction, TEM images and Vibrating Sample Magnetometer (VSM). We collected the experimental data reported in the literature, for the same conditions, and after fitting, extrapolating and doing some calculations. The magnetization for smaller nanoparticles is bigger for the samples we consider here. This difference could be explained by the difference of surface volume ratio of nanoparticle which shows the contribution of the paramagnetic surface is more important with respect to the anti-ferromagnetism of the core for smaller particles. Also the nanoparticle at lower temperatures shows bigger magnetization.

Fabrication and Investigation of the Magnetic Properties of Co and Co3O4 Nanoparticles

The nanoparticles exhibit some novel optical and magnetic properties, which are different from its bulk material. Cobalt oxide has been known as a semi-conductor compound of p type with a Spinel structure. Therefore, they are used as gas sensor and absorbent of solar energy. Furthermore, they are employed as an effective catalyzer in environmental clearing. In the thermal gradation method, carbonyl cobalt Co2(CO)8 is often used as a precursor, though cobalt carbonyl is very toxic and expensive. Magnetic compounds have been among interesting issues for human beings for over 4000 years. In large societies, magnetic compounds including computer disks, credit cards, speakers, coolers, automatic doors, and many other devices can be observed on a daily basis. The structure and morphology of as-prepared Co3O4 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The TEM images showed that the product nanoparticles consisted of dispersive quasi- spherical particles with a narrow size distribution ranged from 5 to 15 nm and an average size around 10 nm. The magnetic measurements confirmed that the Co3O4 nanoparticles show a little ferromagnetic behavior which could be attributed to the uncompensated surface spins and finite size effects. The ferromagnetic order of the Co3O4 nanoparticles is raised with increasing the decomposition temperature.

Application of Nanotechnology in Soil Stabilization

Nano-technology is expanding its horizon in various science and technology fields.In civil engineering,soil is a complex material and used for various functions and applications.Meanwhile,sometimes an effective soil stabilization technique is needed to fulfil the site criteria and can be achieved by adopting various methods e.g.,physical,chemical,thermal or reinforcement using geotextiles and fabrics.The mechanism of soil stabilization using nanomaterials is still unexplored and open to prospective researchers.The present article attempts to touch and explore the possibilities of nano-technology in soil improvement and its applications in various civil engineering works.Microstructural analysis of the nanomaterials treated soils using the latest equipment has also been discussed.The study interprets that the use of nano materials is still limited,due to their high cost and sophisticated handling procedures.Though the use of nanoparticles in soil stabilization results in extraordinary improvements in various soil properties,the improved soil properties could be utilized for various geotechnical projects.The present study bridges the past findings to the present scenario of nanomaterials in soil improvement.

STRUCTURAL DETERMINATION OF TITANIUM-OXIDE NANOPARTICLES BY X-RAY ABSORPTION SPECTROSCOPY

As a potential application of titanium-oxide nanoparticles, it is extremely important to investigate a detailed picture of the surface and interior structural properties of nanocrystalline materials, such as rutile and anatase with diameters 7.0 and 4.5nm, respectively. X-ray absorption spectroscopy has been used to identify the local Ti environment and related electronic structure. We combine the experimental results at the Ti edge in both bulk and nano-crystals to determine the lattice distortion in terms of differently characteristic preedge features and the variation in the multiple-scattering region of X-ray absorption near-edge structure (XANES) spectra. The relationship between the transition peaks and the surface-to volume ratio is also discussed.

Formation of AlN Nano Particles Precipitated in St-14 Low Carbon Steel by Micro and Nanoscopic Observations

In low carbon steels, dissolution and precipitation of the second phases such as carbides and nitrides during annealing cycles can affect the final structure and properties of the materials. The interaction of above processes depends on parameters such as reheating temperature, heating rate, annealing temperature, soaking time and finishing temperature in hot rolling stage before cold rolling. The effects of heating rate and annealing temperature on the microstructure and hardness were investigated. Two heating rates for annealing temperatures of 550, 610 and 720℃ were applied on cold-rolled specimens and St-14 low carbon steel, which were immediately quenched after isothermal annealing. The intercept method was used tO measure average grain sizes. However, resulted microstructures are dif- ferent for the two heating rates. While pancaked structures were observed in specimens annealed with low heating rate, in samples annealed with high heating rate, equiaxed microstructures were observed. Vickers micro-hardness values decreased at all temperatures, which were more significant at higher temperatures. At longer annealing time, signs of increase of hardness values were detected. All results and observations consistently suggest that a precipitati- on process has occurred concurrently with restoration processes during annealing. In addition, the energy dispersive spectroscopy analysis resulted from transmission electron microscopic micrographs have proved that the nano particles precipitated in grain boundaries are AlN.

Factors Affecting the Reductive Properties of the Core-Shell SiO2-Coated Iron Nanoparticles

In this study, novel core-shell SiO2-coated iron nanoparticles (SiO2-nZVI) were synthesized using a one-step Stoeber method. The Malachite green degradation abilities of the nanoparticles were investigated. The effects of ethanol/distilled water volume ratio, presence and absence of PEG, tetraethyl orthosilicate (TEOS) dosage, and hydrolysis time used in the nanoparticles preparation process were investigated. The results indicated that the SiO2-coated iron nanoparticles had the highest reduction activity when the particles synthesized with ethanol/H2O ratio of 2:1, PEG of 0.15 ml, TEOS of 0.5 ml and the reaction time was 4 h. The SiO2-nZVI nanoparticles were characterized using Transmission Electron Microscopy (TEM), Energy Dispersive Spectrometry (EDS) and powder X-Ray Diffraction (XRD). The results showed that the average particles diameter of the SiO2-nZVI was 20 - 30 nm. The thickness of the outside SiO2 film is consistent and approximately 10 nm. The results indicated that the nanoparticles coated completely with a transparent SiO2-film. Such nanoparticles could have wide applications in dye decolorization.

Climate Shifts and the Role of Nano Structured Particles in the Atmosphere

A global net sum equilibrium in heat exchange is a fact and thus a global climate change doesn’t exist, but climate shifts in climate cells, especially in the northern temperate cell, do. The global climate has been ever since homeostatic, and has recuperated far huger climate impacts in the past. Current climate models need a drastically revision on the focus of carbon dioxide as main driver. Carbon dioxide and other carbon gasses do influence albedo patterns, but provide globally a homeostatic effect with a commonly accepted increase impact of 0.3 degrees Celsius. Carbon dioxide does not trigger the climate shifts, but is an indicator of exhaust of combustion processes that emit very small particles which drive these climate shifts. They are the fine dust and nano structured particles that cause the shifts of the climate in cells, as demonstrated in this article and results i.e. in more thunder and lightning, extreme weather, distinct droughts and precipitation patterns. The causes underlying these shifts are nano structured particles in the upper troposphere and lower stratosphere, especially largely produced and remain in the temperate climate northern hemisphere cell and get dispersed by jet streams and low and high pressure areas. However, because of electrical charge, caused by friction or due to anthropogenic negatively charged nano structured particle, emissions will travel up to the lower stratosphere and become neutralized at the electro sphere level, and they do also have a tendency to move to the Arctic. The southern hemisphere climate faces limited anthropogenic emissions, because only 10 percent of the world population can contribute with less pollutant providing activities, and hasn’t changed, but that could well be because it is equally influenced and driven, like the northern hemisphere, by the variation of sun activity in diverse cycles. The present problem is that we produce huge amounts of air borne nano structured particles from combustion processes that never exist before. The only nano particles known in nature are those who are limited produced from volcano eruptions and natural forest fires. The natural feedback systems that moderate climate shifts and influence global climate are: convection by cumulonimbus clouds, sea currents and vegetation adaptation. A novel ultra-fine dust electric reduction device (UFDRS-System), created by the author, diminishs to a size of less than 10 nano particles in diameter and thus prevents major electrical drift of nano structured particulates in the upper troposphere and lower stratosphere and contributes largely in purifying the air and thus reduces the effects of climate shifts. Like solving the acid rain problems with sulphuric acid reduction and ozone depletion with CFCs proscription in the past, the present climate shifts can be mitigated via a reduction of the anthropogenic nano structured particulates in the atmosphere. The UFDRS-System together with the given nature’s solutions can re-balance our atmosphere in a period of two years or a little bit longer due to extension of the lifespan of a particle in the stratosphere.

The Nano Pulverization of Traditional Chinese Medicine Liuwei Dihuang

The crude drug of Liuwei Dihuang was pulverized to nano particles to improve its bioavailability. The appropriate technique parameters were studied. Paeonol, typical marker of Liuwei Dihuang , was extracted with organic solveat in ultrasonic and its content was determined by HPLC. The appropriate techrdques parameters are as follows ： rotating speed control 1200 r/ min , grinding time control 50min and mass percent concentration control 3.8% . The experimental results show that the average particle diameter is 161.9 nm and the great majority of the plant cell wall is broken into pieces after nano pulverization. The extraction efficiency of paeonol is increased by 23.5% .

Novel synthesis of cerium oxide nano photocatalyst by a hydrothermal method

Crystalline cubic cerium oxide nano particles have been synthesized from cerium(Ⅲ)nitrate(Ce(NO_(3))_(3).6H2_(O))and sodium hydroxide by a hydrothermal method.The effect of three different molar ratios of the NaOH precipitating agent on structural,optical,and photo catalytic activity was investigated.The synthesized cerium oxide nano particles were characterized by X-ray diffraction(XRD),a UV-vis spectrometer,scanning electron microscope(SEM),energy-dispersive X-ray spectroscopy(EDAX),Raman spectroscopy and X-ray photo electron spectroscopy(XPS).According to the findings,hydrothermally synthesized cerium oxide NPs have a high efficiency for photocatalytic degradation of methylene blue when exposed to UV light.Environmental water pollution is the major issue of the atmosphere.To get fresh water,humans could search the resources to purify the water in simple way and degradation is the one of the methods to purify salt water.

INVESTIGATION OF BONDING IN NANO-SiO_(2) BY Si L_(2,3) X-RAY ABSORPTION NEAR-EDGE STRUCTURE SPECTROSCOPY

The Si L2,3 X-ray absorption near-edge structure (XANES) can be used to probe thelocal structure around Si and derive electronic information of the unoccupied s- andd-like partial density of states in nano-size SiO2. We present Si L2,3-edge for threedifferent size silicates acquired by total electron yield (TEY) at the photoemission sta-tion of Beijing Synchrotron Radiation Facility (BSRF). The Si L2,3-edge spectra areinterpreted based on ab initio full multiple-scattering (MS) calculation. The Si L2.3-edge of nano-size materials has XANES similar to that of a-quartz. The similaritiesbetween the Si L2.3-edge shapes attest to a common molecular-orbital picture of theirSi-O bonding and the same coordination state. However, a considerable broadeningof Si L2,3-edge XANES spectra as decrease of particle size is also an indicative ofpolyhedral distortions.

Electrical and Optical Properties of Nano Aluminum Film/Particle Structure

The electrical and optical effects of particles on the nano aluminum film deposited by thermal evaporation was investigated. From the characterization results of scanning electron microscope（SEM）, the accumulation in tens of nanometers had been observed. The current-voltage（I-V） curve of the sample indicates its nonlinear electrical characters expecting the corresponding nonlinear optical properties. By the theoretical calculation, nonlinear conduction of the carrier transportation may result from the barrier-well-barrier structure, where negative resistance and Coulomb blockade effect appears. The simulation results are approximately matched with the experimental results. By testing the fluorescence emission spectrum of the sample, peaks were found to be located at 420 and 440 nm. In addition, the full width at half maximum（FWHM） had been obviously broadened by means of adding 2, 5-diphenyloxazole（DPO）. Therefore, discrete energy levels could be estimated inside those particles.

Understanding the Mechanism of Nanoparticle Formation in a Wire Explosion Process by Adopting the Optical Emission Technique

In the present study nano-tungsten carbide particles were generated in a wire explosion process.The plasma generated during the wire explosion process was analyzed using optical emission spectroscopy（OES）.The impact of ambient pressure on the plasma temperature,electron density and plasma lifetime was studied.Lifetime variations of the plasma produced under different experimental conditions were analyzed.The produced nanoparticles were characterized through wide angle X-ray diffraction（WAXD） and transmission electron microscopy（TEM） studies. Particles produced with a negative DC charging voltage had a larger mean size when compared to a positive charging voltage.Polarity dependence on the plasma duration was observed where plasma was sustained for a longer duration with a negative DC charging voltage.

Performance analysis of thermal storage unit with possible nano enhanced phase change material in building cooling applications

The heat transfer performance of the phase change materials used in free cooling and air conditioning applications is low,due to the poor thermal conductivity of the materials.The recent phenomenal advancement in nano technology provides an opportunity for an appreciable enhancement in the thermal conductivity of the phase change materials.In order to explore the possibilities of using nano technology for various applications,a detailed parametric study is carried out,to analyse the heat transfer enhancement potential with the thermal conductivity of the conventional phase change materials and nano enhanced phase change materials under various flow conditions of the heat transfer fluid.Initially,the theoretical equation,used to determine the time for outward cylindrical solidification of the phase change material,is validated with the experimental results.It is inferred from the parametric studies,that for paraffinic phase change materials with air as the heat transfer fluid,the first step should be to increase the heat transfer coefficient to the maximum extent,before making any attempt to increase the thermal conductivity of the phase change materials,with the addition of nano particles.When water is used as the phase change material,the addition of nano particles is recommended to achieve better heat transfer,when a liquid is used as the heat transfer fluid.

Anticancer potential of Ferula assa-foetida and its constituents,a powerful plant for cancer therapy

Cancer is one of the main challenges of the health system around the world.This disease is increasing in developing countries and imposes heavy costs on patients and governments.On the other hand,despite various drugs,the death rate among cancer patients is still high and the current treatments have many harmful effects.In the traditional medicine of different countries,there are many medicinal plants that can be effective in the treatment of cancer.Ferula plants are traditionally used as spices and food or for medicinal purposes.Ferula assa-foetida is one of the famous plants of this genus,which has been used for the treatment of various diseases since ancient times.Among the main compounds of this plant,we can mention monoterpenes,sulfide compounds and polyphenols,which can show different therapeutic effects.This article has been compiled with the aim of collecting evidence and articles related to the anti-cancer effects of extracts,derived compounds,essential oils and nanoparticles containing Ferula assa-foetida.This review article was prepared by searching the terms Ferula assa-foetida and cancer,and relevant information was collected through searching electronic databases such as ISI Web of Knowledge,PubMed,and Google Scholar.Fortunately,the results of this review showed that relatively comprehensive studies have been conducted in this field and shown that Ferula assa-foetida can be very promising in the treatment of cancer.

化学还原法制备纳米银粉及性能表征

在低温反应条件下,通过化学还原的方法以双氧水还原银氨配离子,制备了Ag纳米粉,并利用X射线衍射(XRD)、透射电子显微镜(TEM)对样品的成分、形貌、晶体结构、粒度及其分布进行性能表征;用红外吸收光谱(FT-IR)对结构组成进行定性分析;采用热失重分析(TGA)和差示扫描量热分析(DSC)研究了在热处理过程中的物相转变。结果表明:在所选择的实验条件下制备了类球形分布、分散性好的Ag纳米颗粒,其粒径主要分布在10￣50nm范围,平均粒径为26nm,晶体结构与相应的块体材料基本相同,为fcc结构,样品具有很强的吸附性。

纳米银粉在水溶液中的分散及粒径表征

利用直流电弧等离子体蒸发冷凝法制备纳米银粉,采用X射线衍射分析对纳米银粉的结构进行表征,采用纳米激光粒度仪研究不同超声分散工艺与不同离子类型的分散剂聚乙烯吡咯烷酮、十六烷基三甲基溴化氨、十二烷基硫酸钠对纳米银粉在水溶液中分散性能的影响,获得纳米银粉的最佳分散工艺与激光粒径分布,对比研究纳米银粉的激光粒径与透射电镜统计的粒径的差异。结果表明:纳米银颗粒为立方晶系多晶体,颗粒的结晶性良好;以十六烷基三甲基溴化氨为分散剂的效果最理想,最佳超声波功率为600 W;当十六烷基三甲基溴化氨的质量浓度为0.5 g/L时,纳米银颗粒的分散稳定性较好;激光粒径反映的纳米颗粒的动态二次粒径略大于从透射电镜图像统计得到的粒径。

NONCONVENTIONAL EMULSION POLYMERIZATION OF ACRYLONITRILE CATALYZED BY in situ METAL COMPLEX

Nano-sized polyacrylonitrile （PAN） particles were prepared under the catalytic effect of in situ developed CoCl2/EDTA complex with ammonium persulfate as the initiator in the absence of any added emulsifier. The emulsion polymerization was studied at varying concentrations of the initiator, monomer, complex and solvent over a temperature range of 30-70℃. The overall activation energy （Ea, 49.79 kJ/mol）, energy of dissociation of initiator （Ed, 82.68 kJ/mol）, number of micelles （0.163 × 10^18） and the viscosity average molecular weight of the polymer were computed. The distribution of particle sizes was determined by transmission electron microscopy （TEM）. It was found that the oil-in-water polymerization was stabilized by the presence of the CoCl2/EDTA in situ complex reducing the particle size into the nano order. The average diameters of PAN nano particles, obtained by TEM, were in the range of 50-150 nm at the maximum conversion. The experimental particle size was mainly dependent on the concentration of the complex and temperature.