Photocatalytic degradation of dyes and organic contaminants in water using nanocrystalline anatase and rutile TiO2

Nanocrystalline TiO₂ was synthesized by controlled hydrolysis of titanium tetraisopropoxide. The anatase phase was converted to rutile phase by thermal treatment at 1023 K for 11 h. The catalysts were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), Fourier-transform infrared absorption spectrophotometry (FT-IR) and N₂ adsorption (BET) at 77 K. This study compare the photocatalytic activity of the anatase and rutile phases of nanocrystalline TiO₂ for the degradation of acetophenone, nitrobenzene, methylene blue and malachite green present in aqueous solutions. The initial rate of degradation was calculated to compare the photocatalytic activity of anatase and rutile nanocrystalline TiO₂ for the degradation of different substances under ultraviolet light irradiation. The higher photocatalytic activity was obtained in anatase phase TiO₂ for the degradation of all substances as compared with rutile phase. It is concluded that the higher photocatalytic activity in anatase TiO₂ is due to parameters like band-gap, number of hydroxyl groups, surface area and porosity of the catalyst.     

一种改进的α-β目标跟踪滤波算法

数据处理系统是相控阵雷达实现搜索和对多目标精确跟踪的关键部分，目标跟踪滤波算法的优劣将直接决定系统的性能。介绍了一种改进的α-β滤波算法，然后将它和最小二乘滤波算法、卡尔曼滤波算法进行比较，对三种算法跟踪空中目标的直线飞行、改变航向的直线飞行两种情况的距离、方位、速度和航向等参数的均方差加以分析，证明了改进的α-β滤波算法在直线飞行模型下有着很好的综合效果，且计算量小，更有利于系统建模与仿真。     

Formation of high-purity organic thin films by gas flow deposition and the effect of impurities on device characteristics

A gas flow deposition (GFD) system was developed to manufacture large-scale organic light-emitting diodes (OLEDs). A N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (α-NPD) thin film with a high purity of 99.97% was obtained using the GFD system. The film properties such as morphology, and electrical and optical characteristics were almost the same as those of films made by conventional vacuum thermal evaporation.     

Chemical deposition of nanocrystalline nickel oxide from urea containing bath and its use in liquefied petroleum gas sensor

Nanocrystalline nickel oxide (NiO) was deposited onto glass substrates using a chemical deposition method from a bath containing nickel (Ni²⁺) ions and urea at 363 K. The deposition process was based on the reaction between Ni²⁺ and hydroxide ions released from the protolysis of ammonia formed in the decomposition of urea heated at 363 K, which caused to form nickel hydroxide. The structural properties of nickel oxide films were studied by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analyses showed that nanocrystalline nature remained after heating at 523 K for 2 h. Surface morphology of the nickel oxide film showed worm-like mesoporous structure with pore size in a nanometer range. The chemically deposited nickel oxide films were effectively used as a liquefied petroleum gas (LPG) sensor and the maximum response of 36.5% was recorded on exposure to 0.3 vol% of LPG at 698 K.     

Effect of pH on the Crystallization of Homogeneously Precipitated Nanosized PZT Powder

Nanosized lead zirconate titanate (PZT) powder with Zr:Ti ratio in the morphotropic phase boundary region was synthesized by homogeneous precipitation of metal ions. The powder precipitated at 90°C and at pH 6.7 resulted single-phase perovskite lead zirconate titanate powder when calcined at 550°C and above for 4 hours in air. The solution pH and the precipitation temperature strongly affect the composition of the calcined powder. The results obtained by structural characterization of homogeneously precipitated powder were compared with that obtained from the conventional precipitation method using ammonia in terms of crystallization, homogeneity, and microstructure. The homogeneously precipitated powder showed smaller particle size, minimum agglomeration and uniform shape on calcination and annealing. Powdered samples that precipitated by homogeneous precipitation crystallized directly to perovskite PZT, without any intermediate pyrochlore phase formation. In contrast, the NH₃ precipitated powder converted to perovskite PZT via metastable pyrochlore and it showed phase segregation upon annealing at higher temperatures. The reaction kinetics has been studied by X-ray diffraction, differential thermal analysis, and differential scanning calorimetry.     

Spectroscopic studies of sol–gel grown CdS nanocrystalline thin films for optoelectronic devices

CdS is one of the highly photosensitive candidate of II–VI group semiconductor material. Therefore CdS has variety of applications in optoelectronic devices. In this paper, we have fabricated CdS nanocrystalline thin film on ultrasonically cleaned glass substrates using the sol–gel spin coating method. The structural and surface morphologies of the CdS thin film were investigated by X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) respectively. The surface morphology of thin films showed that the well covered substrate is without cracks, voids and hole. The round shape particle has been observed in SEM micrographs. The particles sizes of CdS nanocrystals from SEM were estimated to be～10–12 nm. Spectroscopic properties of thin films were investigated using the UV–vis spectroscopy, Photoluminescence and Raman spectroscopy. The optical band gap of the CdS thin film was estimated by UV–vis spectroscopy. The average transmittance of CdS thin film in the visible region of solar spectrum found to be～85%. Optical band gap of CdS thin film was calculated from transmittance spectrum ～2.71 eV which is higher than bulk CdS (2.40 eV) material. This confirms the blue shifting in band edge of CdS nanocrystalline thin films. PL spectrum of thin films showed that the fundamental band edge emission peak centred at 459 nm also recall as green band emission.     

Molecular Dynamic Simulation of Lattice Distortion Region Produced by Rounded Grain Boundary in Nanocrystalline Materials

The distortion structure in nanocrystalline NiAl is studied using molecular dynamics simulation.The rounded grain boundaries in these nanograins are a direct source for the observed lattice distortion.The change of grain size affects directly the volume fraction of the distorted lattice in the nanograin.     

Reduction of non-digestible oligosaccharides in horse gram and green gram flours using crude α-galactosidase from Streptomyces griseoloalbus

The effectiveness of using crude extracellular α-galactosidase from Streptomyces griseoloalbus for the treatment of horse gram and green gram flours was investigated by comparing with traditional treatments such as soaking and cooking. The enzymatic treatment was most effective and the raffinose content in horse gram flour was reduced by 97.5% and stachyose content by 93.2%. The reduction in the raffinose content of green gram flour was 96.3% and that for stachyose was 91.8%. The information obtained from the present investigation is advantageous for the large-scale production of horse gram flour and green gram flour free of flatulence-causing oligosaccharides.     

Expression and Characterization of Bioactive Recombinant Human α-Lactalbumin in the Milk of Transgenic Cloned Cows

Improvement of the nutritional value of cow milk with transgenic expression of recombinant human α-lactalbumin (α-LA) has been previously attempted. However, the detailed characterization of the recombinant protein and analysis of the transgenic milk components are not explored yet. Here, we first report production of healthy transgenic cows by somatic cell nuclear transfer, in which expression of up to 1.55 g/L of recombinant human α-LA was achieved. The recombinant human α-LA was purified from transgenic milk and displayed physicochemical properties similar to its natural counterpart with respect to molecular weight, structure, and regulatory activity for β-1,4-galactosyltransferase. Additionally, no N-glycosylation was found in the recombinant human α-LA, whereas the endogenous bovine α-LA was glycosylated at the unusual site ⁷¹Asn-Ile-⁷³Cys. Compared with milk from nontransgenic cows, expression of the transgene did not materially alter milk composition, such as fat and protein content. Our research thus provides scientific evidence supporting the feasibility of humanizing cow milk.