In vitro cytotoxicity of surface modified bismuth nanoparticles

This paper describes in vitro cytotoxicity of bismuth nanoparticles revealed by three complementary assays (MTT, G6PD, and calcein AM/EthD-1). The results show that bismuth nanoparticles are more toxic than most previously reported bismuth compounds. Concentration dependent cytotoxicities have been observed for bismuth nanoparticles and surface modified bismuth nanoparticles. The bismuth nanoparticles are non-toxic at concentration of 0.5 nM. Nanoparticles at high concentration (50 nM) kill 45, 52, 41, 34 % HeLa cells for bare nanoparticles, amine terminated bismuth nanoparticles, silica coated bismuth nanoparticles, and polyethylene glycol (PEG) modified bismuth nanoparticles, respectively; which indicates cytotoxicity in terms of cell viability is in the descending order of amine terminated bismuth nanoparticles, bare bismuth nanoparticles, silica coated bismuth nanoparticles, and PEG modified bismuth nanoparticles. HeLa cells are more susceptible to toxicity from bismuth nanoparticles than MG-63 cells. The simultaneous use of three toxicity assays provides information on how nanoparticles interact with cells. Silica coated bismuth nanoparticles can damage cellular membrane yet keep mitochondria less influenced; while amine terminated bismuth nanoparticles can affect the metabolic functions of cells. The findings have important implications for caution of nanoparticle exposure and evaluating toxicity of bismuth nanoparticles.     

Pb distribution in multistep bismuth refining products

Significant amounts of lead impurities have been removed from bismuth using a multistep refining process involving bismuth electrorefining in a hydrochloric acid solution, melting of a cathodic bismuth sponge, and pyrometallurgical processing of molten bismuth in an inert atmosphere. The Pb distribution between bismuth and the products forming in different refining steps has been studied.     

单晶Bi纳米带的合成与表征

采用溶剂热方法,以苯乙烯为还原剂和配位剂,合成了宽度为40nm-60nm、长度为600nm-1μm铋纳米带,并对其反应机理进行了探讨。在铋纳米带的合成中,α-铋的层状结构是形成铋纳米带的关键因素。配位试剂在各晶面的吸附对产物的形貌具有重要影响。通过改变配位试剂与铋盐的质量比,可以实现对铋纳米结构和形貌的调控。     

Thin bismuth oxide films prepared through the sol–gel method

In this paper, thin and uniform bismuth oxide films were prepared by the sol–gel method. These films were annealed at different temperatures. X-ray diffraction, X-ray photoelectron spectroscopy, atom force microscopy techniques, a surface profiler and a spectrophotometer were applied to characterize these bismuth oxide films annealed at different temperatures. The results show that different annealing temperatures cause the transformation between monoclinic phase and tetragonal phase of bismuth oxides, and that bismuth oxide films annealed at 550 °C contain the highest intensity of tetragonal phase of bismuth oxides.     

The photocatalytic properties of bismuth oxide films prepared through the sol-gel method

In this research, thin bismuth oxide films were prepared through the sol-gel method. In order to study the influence of bismuth oxide crystal phases on the photocatalytic properties of bismuth oxide films, these films were annealed at different temperatures and then applied to decompose a typical textile industry pollutant (Rhodamine B). Scanning electron microscopy, X-ray diffraction and profilometry were applied to characterize these films. It has been found that different annealing temperatures cause the transformation of different bismuth oxide crystal phases, which leads to the different removals of Rhodamine B photolyzed using bismuth oxide films as photocatalyst.     

Oxygen vacancy induced bismuth basic nitrate with excellent photocatalytic activity

A novel gray bismuth basic nitrate photocatalyst was synthesized. The results of Raman scattering spectroscopy, X-ray photoelectron spectroscopy and photoluminescence spectroscopy supported the presence of oxygen vacancies. Gray bismuth basic nitrate exhibits higher activity than white bismuth basic nitrate and BiOCl which is one of the most extensively studied bismuth-based photocatalytic material. The oxygen vacancies and internal electric field in bismuth basic nitrate possibly make it one of the promising materials for the degradation of environmental pollution.     

Novel solution route synthesis of low thermal conductivity nanocrystalline bismuth telluride

A novel synthesis approach based on a solution route has been developed for the fabrication of nanocrystalline bismuth telluride. The method consists of dissolving both bismuth and tellurium into the same organic solvent with the assistance of complexing agents and one-step coprecipitation of bismuth telluride. The synthesized nanocrystalline bismuth telluride powders possess rhombohedral crystal structure and are nanosheet/nanorod-like with an average size of between 30 and 40 nm. The thermal conductivity of the hot-pressed compact consolidated from the as-synthesized nanopowders is 0.39-0.45 Wm(-1)K(-1) in the temperature range of 323 to 523 K, which is at most one third of that of bulk bismuth telluride-based materials reported in the literature. Such low thermal conductivity of the investigated bismuth telluride is mainly attributed to substantially high concentration of grain boundaries provided by nanostructuring to scatter phonons intensively.     

Calorimetric measurements of nuclear quadrupole interactions in tellurium-doped bismuth

By doping bismuth with tellurium to increase the charge carrier density and thus speed up the slow nuclear spin-lattice relaxation the nuclear quadrupole heat capacity becomes measurable in contrast to pure bismuth. The quadrupole heat capacity is greatly influenced by doping, increasing by 64% over the pure bismuth value on the addition of 0.23 at. % of tellurium. This results from a local asymmetric distortion of the valence electron states of the bismuth ions around the impurity site.     

Intercalation of copper into bismuth telluride

The intercalation and leaching of copper into and out of bismuth telluride was investigated using aqueous and solid state electrochemical methods. It was found that copper intercalates up to a concentration of 3 mg/g bismuth telluride. Copper may also react with bismuth telluride to form copper telluride (Cu₂Te). Boiling hydrochloric acid leaches, or controlled potential electrochemical leaches, were effective at removing intercalated copper from bismuth telluride, returning the bismuth telluride to its original, undoped state. E.m.f. measurements using a solid, copper-ion conducting electrolyte resulted in copper activities of between 0.000 73 and 0.044 for intercalated bismuth telluride. An effective copper diffusion coefficient of 4×10^–5 cm²s^–1 was measured for a sintered polycrystalline bismuth telluride pellet at 483 K.This work was conducted at the Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3Q2, UK     

Biosynthesis of bismuth nanoparticles using Serratia marcescens isolated from the Caspian Sea and their characterisation

Today, synthesis of nanoparticles (NPs) using micro-organisms has been receiving increasing attention. In this investigation, a bismuth-reducing bacterium was isolated from the Caspian Sea in Northern Iran and was used for intracellular biosynthesis of elemental bismuth NPs. This isolate was identified as non-pigmented Serratia marcescens using conventional identification assays and the 16s rDNA fragment amplification method and used to prepare bismuth NPs. The biogenic bismuth NPs were released by liquid nitrogen and highly purified using an n-octanol water two-phase extraction system. Different characterisations of the purified NPs such as particle shapes, size and purity were carried out with different instruments. The energy-dispersive X-ray and X-ray diffraction (XRD) patterns demonstrated that the purified NPs consisted of only bismuth and are amorphous. In addition, the transmission electron micrograph showed that the small NPs formed larger aggregated NPs around <150?nm. Although the chemical syntheses of elemental bismuth NPs have been reported in the literature, the biological synthesis of elemental bismuth NPs has not been published yet. This is the first report to demonstrate a biological method for synthesising bismuth NPs and their purification with a simple solvent partitioning method.     

Enhanced activity of bismuth-compounded TiO(2) nanoparticles for photocatalytically degrading rhodamine B solution

TiO(2) nanoparticles compounded with different amounts of bismuth were prepared by a sol-gel method, and the effects of compounding bismuth on the phase transformation, photoinduced charge separation and photocatalytic activity for degrading rhodamine B solution were mainly investigated, along with enhancement mechanism of photocatalytic activity of TiO(2) nanoparticles by compounding bismuth species. It can be confirmed that, by means of X-ray diffraction (XRD), surface photovoltage spectroscopy (SPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), compounding bismuth can extend the optical response, and effectively inhibit the phase transformation process from anatase to rutile, consequently greatly improving the anatase crystallinity so as to promote the photoinduced charge separation. These factors are responsible for the increase in the photocatalytic activity of TiO(2) compounded with an appropriate amount of bismuth species.     

Determination of the purity of bismuth and bismuth oxide by atomic absorption spectrometry

To enable high-speed analyses in the preparation of high-purity bismuth and bismuth oxide, we have developed an atomic absorption technique which ensures Ag, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Te detection limits in the range 2 × 10⁻⁷ to 2 × 10⁻⁵ wt %. The technique was used to assess the purity of bismuth and bismuth oxide in metal refining and oxidation steps.     

二甲基亚砜溶剂中化学镀铋的研究

为了克服传统的电化学沉积铋使镀液不稳定,镀层受析氢影响的缺点,研究了一种新的以二甲亚砜为溶剂的化学镀铋体系,提出了两种可以沉积出银白光亮致密铋镀层的配方.探讨了不同基体上化学沉积铋的情况,结果以在铁片和铜片上沉积效果好,可作为代铬镀层应用.初步用电化学方法探讨了化学镀的机理,即先由铜提供电子,而后铋自催化使镀层增厚.用EDAX分析镀层确认只含铋,用XRD对镀层进行表征,证明了镀层中的铋以金属晶体存在,平均粒径为38 nm.     

Bismuth-induced embrittlement of copper grain boundaries

Catastrophic brittle fracture of crystalline materials is one of the best documented but most poorly understood fundamental phenomena in materials science. Embrittlement of copper by bismuth is a classic example of this phenomenon. Because brittle fracture in any structural material can involve human tragedy, a better understanding of the mechanisms behind it is of the highest interest. In this study, we use a combination of two state-of-the-art atomic characterization techniques and ab initio theoretical materials simulations to investigate the geometric and electronic structure of a copper grain boundary with and without bismuth. Only with this unique combination of methods are we able to observe the actual distribution of bismuth in the boundary and detect changes in the electronic structure caused by the bismuth impurity. We find that the copper atoms that surround the segregated bismuth in the grain boundary become embrittled by taking on a more zinc-like electronic structure.     

Application of BiFeO3 and Bi4Ti3O12 in ferroelectric memory, phase shifters of a phased array, and microwave HEMTs

This paper examines the main applications of bismuth ferrite and bismuth titanate and demonstrates their potential applications in spintronics and radioelectronics.     

Characterization and fracture behavior of bismuth–tin thermal fuse alloy wires produced by the Ohno continuous casting process

Bismuth–tin binary alloys containing high bismuth concentrations of 40 to 77% were continuously cast into wires of approximately 2 mm in diameter with casting speeds between 15 and 150 mm min^?1 using the Ohno Continuous Casting (OCC) process. The microstructure was examined and tensile tests were performed for wires cast at various speeds. It was found that for slowly cast wires containing large primary bismuth dendrites, bismuth fracture occurring along the (111) plane exerted a key role in wire fracture, while microstructures with refined bismuth dendrites exhibited a mixture of bismuth cracks and inter-phase decohesion, allowing the accommodation of larger strain before wire fracture. For wires with microstructures containing primary tin dendrites, inter-phase decohesion played a key role in wire fracture.     

二甲基亚砜中半导体上脉冲电沉积Bi薄膜

从原有的化学镀铜的工业配方出发，对其用量进行改良，特别是镀液的pH值调试，配体的使用和还原剂的用量，在硅片上沉积出一层光亮而且致密的铜薄膜。结果表明，在二甲基亚砜中硅铜基体上的电沉积铋薄膜均匀、致密、粘附力强，XRD测试表明铋以晶体析出。     

铋含量对钛酸镧铋陶瓷结构和介电性能的影响

通过固相合成的方法制备了Bi3.25,LaxTi3O12（x=0．98～1．03，简称BLT）陶瓷。通过XRD，SEM和阻抗分析仪表征了陶瓷的晶体结构和晶体形貌，测试了陶瓷的介电频谱，结果表明陶瓷的晶体结构为典型的层状钙钛矿结构且不随Bi含量和温度的变化而改变；随着Bi含量的增加晶体形貌由棒状颗粒向片状颗粒转变，而且陶瓷的致密度也得到提高；介电常数随Bi含量的增加先增大后减小，并且在x=1．02时达到最大值。     

An electron microscopic study on MnBi thin films

The structure and orientation of MnBi thin films prepared by sequential evaporation of bismuth and manganese on glass substrates were studied by transmission electron microscopy and electron diffraction. Results indicate that these films develop a preferred orientation with thec-axis perpendicular to the film plane. This preferred orientation is due to the formation of MnBi from a highly oriented bismuth layer, i.e., a layer with thec-axis perpendicular to the film plane. Trace amounts of elemental bismuth, manganese and MnO are found in these MnBi films. There is evidence of close parallel alignment between the MnBi and the bismuth lattices.     

超声波对锡铋合金电镀层的影响

将超声和电沉积相结合电镀了锡铋合金.通过扫描电镜(SEM)和X射线衍射(XRD)对镀层的表面形貌和结晶状态进行了表征,并用光栅光谱法对镀层成分进行了分析,研究了超声波功率对锡铋合金镀层的影响.结果表明:超声波的作用使镀层表面更细致均匀,结晶晶面仍具有以Sn(101)面为主的择优取向,镀层中锡和铋的含量增加,且铋的增加更为显著.超声波提高了镀层的表面性能和质量,加快了电沉积速度,并有利于铋的电沉积和合金的形成,而镀层的择优取向不变,仅择优系数略有降低.