Composition Design and Luminescent Properties of Sr_（1-y）Ca_yWO_4 Ceramic Thin Films

采用原电池电化学法制备了钨酸锶钙（Sr1–yCayWO4）薄膜。利用X射线衍射仪、能谱仪和荧光计等对薄膜进行分析,并研究了薄膜中钙含量（y）与溶液中钙含量（x）之间的半定量关系。研究表明,所得薄膜为多晶膜,钙占据白钨矿结构的钨酸盐AWO4中A位晶格;可根据经验公式y=0.168＋0.79x（0.2≤x≤0.8）来半定量地控制膜中的钙含量。随着x的增加,制备的Sr1–yCayWO4多晶体的形貌由SrWO4的双锥形演变到CaWO4的花束状团簇。在258 nm的紫外光激发下,可观测到位于415 nm和463 nm处的2个发光带;发光强度并不随着x的增加表现出规律性的变化,但当x=0.2时制备的Sr1–yCayWO4薄膜样品的发光强度最大。     

Effects of Heat Treatment on Structural,Optical and Magnetic Properties of Electro Deposited Fe–Ni–P Thin Films

Nanocrystalline Fe–Ni–P thin films have been prepared by electrodeposition method for different temperature. The structural, morphological, mechanical and magnetic properties are analyzed by different measurements. The structural and surface morphology of thin film were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD results showed all the electro deposited Fe–Ni–P films exhibits nanocrystalline FCC structure. The SEM pictures of Fe–Ni–P thin films show that the deposits of thin films are crack free, uniform and bright surface. The mechanical properties of Fe–Ni–P thin films have been analyzed by VHT. The electroplated Fe–Ni–P thin films were strongly adherent to the copper substrate. The VHT result of Fe–Ni–P thin films shows that thin film coated at high bath temperature has highest hardness value. Also VSM result shows that thin film coated at high bath temperature has higher magnetization value. This shows that the soft magnetic properties of Fe–Ni–P thin films are greatly enhanced by various temperatures.     

Preparation of La1?x Sr x CoO3 Oxide Electrode Material and its Influence on the Structure and Dielectric Performance of the Supported Ba1?x Sr x TiO3 Thin Films

Using the sol–gel method, La_1−x Sr _x CoO₃ (LSCO) electrode films were first fabricated on the Si (100) substrates, followed by the growth of Ba_1−x Sr _x TiO₃ (BST) thin films on the LSCO electrode film. The crystal structure and surface morphology of these films were characterized by XRD and SEM. The effects of Sr-doping and annealing temperature on the structure and electric resistivity of the LSCO films and the dielectric properties of the BST films were studied. Results show that the La_0.5Sr_0.5CoO₃ electrode annealed at 750 °C has the lowest electric resistivity, 1.1 × 10⁻³Ω cm. The relative permittivity of the La_0.5Sr_0.5CoO₃-supported BST films first increases and then decreases with Sr-doping. The relative permittivity of the BST film decreases while the dielectric loss increases with frequency. Among the studied BST films, Ba_0.5Sr_0.5TiO₃ has the largest relative permittivity and the smallest dielectric loss (95 and 0.1, respectively) when the frequency is 1 kHz.     

Elastic Properties of 4–6 nm-thick Glassy Carbon Thin Films

Glassy carbon is a disordered, nanoporous form of carbon with superior thermal and chemical stability in extreme environments. Freestanding glassy carbon specimens with 4–6 nm thickness and 0.5 nm average pore size were synthesized and fabricated from polyfurfuryl alcohol precursors. Elastic properties of the specimens were measured in situ inside a scanning electron microscope using a custom-built micro-electro-mechanical system. The Young’s modulus, fracture stress and strain values were measured to be about 62 GPa, 870 MPa and 1.3%, respectively; showing strong size effects compared to a modulus value of 30 GPa at the bulk scale. This size effect is explained on the basis of the increased significance of surface elastic properties at the nanometer length-scale.     

Electrical and Optical Properties of Vinylidene Fluoride—Trifluoro Ethylene Copolymers Prepared by Solution Cast

Abstract

The dielectric and non-linear optical properties of a 60/40 copolymer of vinylidene fluoride with trifluoro ethylene prepared as thin films by a solution cast procedure are described. The relation of these properties with the microstructure of the system as derived by wide and small angle X-ray scattering experiments is also discussed. Some implications regarding to the use of these copolymers in electrooptics are pointed out.     

Effect of Biopolymer Blend Matrix on Structural,Optical and Biological Properties of Chitosan–Agar Blend ZnO Nanocomposites

The present research is focused on the development of ecofriendly biopolymer blend based nanocomposites to enhance the effect of cytotoxic activity. Novel eco-friendly synthesis of pure Chitosan–Agar blend and Chitosan–Agar/ZnO nanocomposites was successfully synthesized by in-situ chemical synthesis method. The influence of Chitosan–Agar (1:1 wt/wt%) concentrations (0.1, 0.5, 1 and 3 g) was studied. The presence of ZnO nanoparticles in Chitosan–Agar polymer matrix was confirmed by UV, FTIR, XRD, FESEM, EDAX and TEM. The crystallite size of the nanocomposites in the range of 12–17 nm is observed from XRD analysis. PL and UV reveal that Nanocomposites shows an blue shift by increase in the blend concentrations. TEM analysis shows that 0.1 and 3 g of Chitosan–Agar/ZnO Nanocomposites are in spindle and spherical shape with polycrystalline nature. The prepared Nanocomposites shows the respectable Antibacterial activity against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Pseudomonas aureginosa and Klebsilla pneumonia) bacteria. The potential toxicity of Chitosan–Agar/ZnO nanocomposites was studied for normal (L929) and breast cancer cell line (MB231). The result of this investigation shows that the Chitosan–Agar/ZnO nanocomposites deliver a dose dependent toxicity in normal and cancer cell line.     

Effect of γ-Irradiation on Electrical Conductivity of Metal-Chloride-Treated Polyacrylamide

The electrical conductivity of polyacrylamide (PAAm) before and after treatment with low concentrations of ZnCl₂, NiCl₂, and CoCl₂ was determined at different temperatures. The effects of γ-irradiation on the electrical conductivity and activation energy of the original and the metal-chloride-treated specimens were investigated. The experimentally obtained data revealed that the conduction in PAAm is ionic in nature. The treatment of the polymer with 2% or 4% (w/w) of ZnCl₂, NiCl₂, or CoCl₂, as determined from its weight, either increases or decreases its conductivity according to the nature of the metal ions, concentration of metal chloride, ratio of KOH/metal chloride, and temperature and cycle of measurement. The exposure of PAAm to 2 to 10 Mrad of γ-radiation produces no significant changes in its conductivity. On the other hand, the exposure of the PAAm pretreated with a metal chloride produces considerable changes in its conductivity. Also, the γ-irradiation of PAAm increases its activation energy. The extent of the γ-induced changes in activation energy was influenced by the pretreatment of PAAm with metal chlorides.     

Intense Red Catho- and Photoluminescence from 200 nm Thick Samarium Doped Amorphous AlN Thin Films

Samarium (Sm) doped aluminum nitride (AlN) thin films are deposited on silicon (100) substrates at 77 K by rf magnetron sputtering method. Thick films of 200 nm are grown at 100–200 watts RF power and 5–8 m Torr nitrogen, using a metal target of Al with Sm. X-ray diffraction results show that films are amorphous. Cathodoluminescence (CL) studies are performed and four peaks are observed in Sm at 564, 600, 648, and 707 nm as a result of ⁴G_5/2 → ⁶H_5/2, ⁴G_5/2 → ⁶H_7/2, ⁴G_5/2 → ⁶H_9/2, and ⁴G_5/2 → ⁶H_11/2 transitions. Photoluminescence (PL) provides dominant peaks at 600 and 707 nm while CL gives the intense peaks at 600 nm and 648 nm, respectively. Films are thermally activated at 1,200 K for half an hour in a nitrogen atmosphere. Thermal activation enhances the intensity of luminescence.     

Synthesis of High Coercivity Core–Shell Nanorods Based on Nickel and Cobalt and Their Magnetic Properties

Hybrid magnetic nanostructures with high coercivity have immense application potential in various fields. Nickel (Ni) electrodeposited inside Cobalt (Co) nanotubes (a new system named Ni @ Co nanorods) were fabricated using a two-step potentiostatic electrodeposition method. Ni @ Co nanorods were crystalline, and they have an average diameter of 150 nm and length of ~15 μm. The X-ray diffraction studies revealed the existence of two separate phases corresponding to Ni and Co. Ni @ Co nanorods exhibited a very high longitudinal coercivity. The general mobility-assisted growth mechanism proposed for the growth of one-dimensional nanostructures inside nano porous alumina during potentiostatic electrodeposition is found to be valid in this case too.     

The Effect of Surface Roughness and Composition on Wetting and Corrosion of Al−Si Alloys

This paper presents results of wetting and corrosion of cast Al−Si alloys with composition varying from 7–50 wt% Si in contact with water. The dependency of the wetting angle and corrosion properties on the alloy composition, surface roughness, size of water droplets, and microstructure were studied. An increase in the Silicon content reduced the water contact angle (WCA) while an increase in the roughness and/or droplet size increased the WCA. No systematic variation in corrosion was found due to change in the Silicon content. The results are of interest for the development of lightweight (Al−Si) alloys with non-wetting and corrosion-resistant properties.     

Effect of Ionic Liquids on Surface and Aggregation Properties of Non-ionic Surfactant Triton™ X-100 in Aqueous Media

The effect of the hydrophilic ionic liquids (ILs) 1-butyl-2,3-dimethylimidazolium bromide [bdmim][Br] and 1-hexyl-2,3-dimethylimidazolium bromide [hdmim][Br] on the aggregation and surface active behaviour of the non-ionic surfactant Triton? X-100 (TX-100) was studied in aqueous media. Several aggregation properties of TX-100 + IL/water systems, such as critical micelle concentration (CMC), surface active parameters, aggregation number (N _agg) and aggregate size, were determined by surface tension, fluorescence and dynamic light scattering (DLS) techniques. It was found that the average micellar size and aggregation number decrease, whereas the CMC increases with increasing concentration of ILs. Interestingly, the CMC value of TX-100 is reduced slightly below 0.5 wt% of both the ILs in the medium. At higher wt% of IL in the system the CMC increases. It was demonstrated that ILs [bdmim][Br] and [hdmim][Br] can be judiciously used at different wt% for modifying the physico-chemical properties of TX-100.     

Effect of Direct Dyes on the Physical and Mechanical Properties of α-Keratin Fibers

Fibre Chemistry - The effect of direct dyes on the physical and mechanical properties of human hair (a-keratin fibers) in the native state and subjected to bleaching with Estel haute couture...     

Effect of Molding Press Direction on Properties of Periclase-spinel-carbon Brick

The effect of press direction on the thermal expansion,slag resistance,etc.of periclase-spinel-carbon brick has been studied in this article.The results show that the therma‘ expansion rate in the direction parallel to the press axis is larger than that in the direction perpendicular to the press axis and the slag resistance in the direction parallel to the press axis is much better than that in the perpendicular direction.The directional distribution of graphite in the specimen is observed with the microscope.     

Influence of Solvent–Evaporation Effect on the Structure and Properties of PVDF-g-PNIPAAm Membranes

Temperature-sensitive poly(vinylidene fluoride)-graft-poly(N-isopropylacrylamide)(PVDF-g-PNIPAAm) copolymer was synthesized and its flat membranes were prepared through phase inversion method with mixture of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) as solvent in water coagulation bath. The effects of “open time” (solvent–evaporation time) on the structure and performance of membranes were investigated by X-ray photoelectron spectroscopy, field-emission scanning electronic microscopy, contact angle, filtration experiments and static protein adsorption. It was found that the increasing “open time” endowed the membrane with more pores on the surface, higher flux and better hydrophilicity, provided the membrane with lower protein adsorption. Thus, the copolymer membranes showed a good antiprotein fouling.     

Metal-Ion Type Effect on the Crystal Structure and Optical Properties of 2,2′-bipyridine Complexes of Pb(II) and Cd(II)

To investigate the effect of metal ion type on the crystal structure and optical and thermal behaviors of coordination compounds, two homometal and one heterometal 2,2′-bipyridine complexes of Pb(II) and Cd(II) have been synthesized and characterized by elemental analysis, PXRD, FT-IR and single crystal X-ray diffraction. Crystal structure analysis of heterometal coordination polymer, [Pb₂Cd(2,2′-bipy)₄(NO₃)₆]_n, displays the attendance of a centrosymmetric 1D coordination polymer that crystallizes in the triclinic system with the space group of \({\text{p}}_{1}^{ - }\). Thermal behavior of prepared coordination compounds was examined under air atmosphere by thermogravimetric analysis. The study of optical properties of compounds showed that metal ion type of coordination compounds is influential on their photophysical properties. Moreover, heterometal coordination polymer was doped into a PVK:PBD blend in two different concentrations as a light emitting material in the fabrication of two organic light-emitting diodes.     

Effect of Microsilica Addition on the Properties of Mullite-Corundum Ceramic

1IntroductionCorundum-mullite materials have been recognizedand adopted as important refractories because of theirexcellent properties,such as high refractoriness,highresistance to creep,good mechanical and chemical sta-bility at high temperatures,high th…     

Adhesion and Scratch Resistance of Polycarbonate Films on Ferroplate Substrates: Effect of γ-APS Primers

The influence of γ-aminopropyltriethoxysilane (γ-APS) primers on the adhesion and scratch resistance of polycarbonate (PC) films on ferroplate substrates was determined from the critical normal loads at which debonding of the films from the substrates occurred during scratch testing. The critical load was a strong function of the concentration of the aqueous solutions from which the γ-APS primers were adsorbed and of the thickness of the primer films. Thus, the critical normal load increased from 0.09 ± 0.02 N to 0.31 ± 0.07 N as the concentration of the γ-APS solutions increased from 0.05% to 0.2%, respectively. However, the critical load increased only slightly as the solution concentration increased beyond 0.2%. The increase in critical load as concentration of γ-APS solutions increased was related to the formation of an interphase involving chemical reaction and physical entanglement of PC and γ-APS molecules. The critical load for debonding of PC films from the substrates also depended strongly on the temperature at which the γ-APS films were dried before application of the PC films. Thus, the critical normal loads for debonding were 0.31 ± 0.07, 0.20 ± 0.02, and 0.05 ± 0.01 N for γ-APS films that were dried for 15 min at room temperature, 60°C, or 110°C, respectively. The decrease in critical load with increasing drying temperature was attributed to the greater cross-link density in γ-APS films that were dried at elevated temperatures, which limited interdiffusion and physical entanglement of PC and γ-APS molecules. High reaction temperature of γ-APS and PC induced a fragmentation of amine. However, it also increased the probability of amines to react with carbonate because of increasing mobility of PC chains. Optimization of these two factors was required to obtain the greatest adhesion and scratch resistance. Chemical reactions occurring between PC films and γ-APS primers were investigated by reflection–absorption infrared spectroscopy (RAIR) and X-ray photoelectron spectroscopy (XPS) using diphenyl carbonate (DPC) as a model compound. The carbonyl absorption band of neat DPC was observed at 1780 cm^?1. However, two carbonyl bands were observed at 1738 and 1652 cm^?1 in RAIR spectra of γ-APS films that were reacted with DPC and were assigned to urethane and urea groups, respectively. XPS results revealed that urethane was the main reaction product between DPC and γ-APS. It was concluded that urethane groups formed by the reaction of PC with γ-APS were responsible for adhesion and scratch resistance of PC to ferroplate substrates that were primed with γ-APS.     

Effect of γ-Irradiation on the Electrical Properties of Poly (Methyl Methacrylate) Doped with Some Transition Metal Complexes

Abstract

The electrical resistivity (p) of pure and doped poly(methyl methacrylate), PMMA, with dithizone (HDZ) and its metal complexes, Zn(HDZ)₂, Cd(HDZ)₂ and Hg(HDZ)₂ has been investigated before and after γ-irradiation. The results show a phase transition at nearly 323°K. The activation energy of the conduction process has been calculated below and above the transition temperature. Further information concerning the electrical behaviour is obtained by considering the type and mechanism of the conduction process. This has been achieved by studying the effect of temperature and γ-irradiation on the mobility and the number of charge carriers which take part in the conduction process.     

Effect of 50 MeV Li+3 Ion Beam Irradiation on Thermomechanical Properties of PMMA/PC Blend Films

This paper reports the effect of the irradiation of 50 MeV Li⁺³ ions on the thermomechanical properties of PMMA/PC blends. The radiation has been carried out at fluences of 10¹⁰ to 10¹² ions/cm² to observe any kind of chain scissoring/crosslinking occurring in the sample. The irradiated as well as the pristine samples have been characterized using X-ray diffraction (XRD), Fourier transform spectroscopy (FTIR), scanning electron microscopy (SEM) and dynamic mechanical analyzer (DMA) to study the induced changes in the structural, morphological and mechanical properties in blend films. The XRD results show an increase in the degree of crystallinity upon ion irradiation at low fluences (≤10¹¹ ions/cm²) and a decrease in crystallinity at high fluences (>10¹¹ ions/cm²), while the FTIR spectra show no appreciable change after irradiation. The mechanical characterization reveals that radiation significantly modifies the mechanical properties and the glass transition temperature of these polymeric blends.     

Effect of Sintering Additive on the Properties of Sialon-SiC by Gelcasting

Sintering additivesto gelcasting Sialon‘SiC were decided by the optimizing experiments , The resuhs show that Sialon-SiC can be sintered under 1450℃ and sintering temperature dcreases by 100℃，when 2%～3% TiO2 or Guangxi clay is used as sintering additive.