Micron sized hexagon- and flower-like nanostructures of lead oxide（α-PbO2） have been synthesized by very simple and cost effective route of anodic oxidation of lead sheet. These structures were easily obtained by t...Micron sized hexagon- and flower-like nanostructures of lead oxide（α-PbO2） have been synthesized by very simple and cost effective route of anodic oxidation of lead sheet. These structures were easily obtained by the simple variation of applied voltage from 2-6 V between the electrodes. Lead sheet was used as an anode and platinum sheet served as a cathode. Anodic oxidation at 2 V resulted in the variable edge sized（1-2 μm） hexagon-like structures in the electrolyte. When the applied potential was increased to 4 V a structure of distorted hexagons consisting of some flower-like structures were obtained. Further increment of potential up to 6 V resulted in flower like structures of α-PbO2 having six petals. The diameter of the flower-like structures was 200-500 nm and the size of a petal was 100-200 nm.展开更多
The deposition of copper selenide(CuSe)thin films was carried out using liquid phase chemical bath deposition process at the optimized growth parameters as:60℃deposition temperature,90 minutes deposition time,pH equa...The deposition of copper selenide(CuSe)thin films was carried out using liquid phase chemical bath deposition process at the optimized growth parameters as:60℃deposition temperature,90 minutes deposition time,pH equal to 10.5±0.1 and 72±2 r/min speed of mechanical rotation.The as-grown deposits exhibited excellent uniformity and physical adherency with the substrate surface and are smooth and diffusely reflecting with colour changing from yellowish orange to dark chocolate during deposition.The layer is of the order of 300 nm thick.The EDS analysis technique gave film composition to be nearly stoichiometric(Cu=47.89%,Se=52.11%).An X-ray diffraction analysis showed CuSe to be polycrystalline hexagonal with a good match of d-values and intensities of reflections.The crystallite size is in the nanorange(50-60 nm).The as-deposited CuSe exhibited a high coefficient of absorption(α=105cm-1)with a direct optical band gap of 1.81 eV.Compared to other chalcogenides,CuSe films exhibit low resistance;room temperature electrical resistivity being 1.55×103?cm.The electrical conductivity decreased with increase in temperature up to 473 K;showing totally unusual behaviour from that of the semiconducting property.The thermo probe measurements showed n-type conduction of the samples.展开更多
Hexagonal trumpet-like sodium hexafluorosilicate （SFS） flowers, grown on an ordered porous polystyrene film （OPPF）, were prepared via a synchronous dissolution/regrowth process. Their formation process can be divi...Hexagonal trumpet-like sodium hexafluorosilicate （SFS） flowers, grown on an ordered porous polystyrene film （OPPF）, were prepared via a synchronous dissolution/regrowth process. Their formation process can be divided into several steps： first, the dissolution of the silica spheres induced the crystallization of SFS onto the OPPF; second, some pores emerged on the closely packed bumps when being blown by the SiF4 gas; third, when the crystal was blown by continuous gas from the pores, the span of the top became larger than that of the bottom.展开更多
基金financial support from USACH-Chile, Council of Scientific and Industrial Research (CSIR) and University Grant Commission (UGC) New Delhi, India
文摘Micron sized hexagon- and flower-like nanostructures of lead oxide（α-PbO2） have been synthesized by very simple and cost effective route of anodic oxidation of lead sheet. These structures were easily obtained by the simple variation of applied voltage from 2-6 V between the electrodes. Lead sheet was used as an anode and platinum sheet served as a cathode. Anodic oxidation at 2 V resulted in the variable edge sized（1-2 μm） hexagon-like structures in the electrolyte. When the applied potential was increased to 4 V a structure of distorted hexagons consisting of some flower-like structures were obtained. Further increment of potential up to 6 V resulted in flower like structures of α-PbO2 having six petals. The diameter of the flower-like structures was 200-500 nm and the size of a petal was 100-200 nm.
文摘为了进一步研究用球磨法制备B C N物质的规律性,在4 5～5 8GPa压力、800～1300℃温度条件下,对用球磨法获得的石墨 六角氮化硼微晶混合物进行高压热处理。热处理后产物的XRD、XPS及FT IR测试表明:在4.5GPa、800℃时,样品中出现部分hBN晶化现象,但石墨仍然保持微晶状态;当温度升到1300℃时,样品中不仅存在晶化的hBN,而且出现一种类石墨结构的B C N三元化合物。与相关研究资料对比后认为:这一新化合物近似于BC3N。压力增加到5 8GPa而温度保持1300℃时,结果变化不大。
文摘The deposition of copper selenide(CuSe)thin films was carried out using liquid phase chemical bath deposition process at the optimized growth parameters as:60℃deposition temperature,90 minutes deposition time,pH equal to 10.5±0.1 and 72±2 r/min speed of mechanical rotation.The as-grown deposits exhibited excellent uniformity and physical adherency with the substrate surface and are smooth and diffusely reflecting with colour changing from yellowish orange to dark chocolate during deposition.The layer is of the order of 300 nm thick.The EDS analysis technique gave film composition to be nearly stoichiometric(Cu=47.89%,Se=52.11%).An X-ray diffraction analysis showed CuSe to be polycrystalline hexagonal with a good match of d-values and intensities of reflections.The crystallite size is in the nanorange(50-60 nm).The as-deposited CuSe exhibited a high coefficient of absorption(α=105cm-1)with a direct optical band gap of 1.81 eV.Compared to other chalcogenides,CuSe films exhibit low resistance;room temperature electrical resistivity being 1.55×103?cm.The electrical conductivity decreased with increase in temperature up to 473 K;showing totally unusual behaviour from that of the semiconducting property.The thermo probe measurements showed n-type conduction of the samples.
基金supported by the National Natural Science Foundation of China(Nos.51273056,21202091,5121010502,21074031)Postdoctoral Science Foundation Projects of China(No.2013M531008)Heilongjiang Provincial Department of Education(No.12521398)
文摘Hexagonal trumpet-like sodium hexafluorosilicate （SFS） flowers, grown on an ordered porous polystyrene film （OPPF）, were prepared via a synchronous dissolution/regrowth process. Their formation process can be divided into several steps： first, the dissolution of the silica spheres induced the crystallization of SFS onto the OPPF; second, some pores emerged on the closely packed bumps when being blown by the SiF4 gas; third, when the crystal was blown by continuous gas from the pores, the span of the top became larger than that of the bottom.
