Papers by Keyword: Preparation

Abstract: SO₄^2-/TiO₂, SO₄^2-/Fe₂O₃ nanoparticles were prepared by the impregnation precipitation method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy disperse spectroscopy (EDS) results showed that the uniform size of SO₄^2-/TiO₂, SO₄^2-/Fe₂O₃ nanoparticles with high purity, good dispersivity and particle size range from 50nm to 200nm. A comparative study between SO₄^2-/TiO₂ and SO₄^2-/Fe₂O₃ nanoparticles applied in the photocatalytic experiment on unsymmetrical dimethylhydrazine (UDMH) wastewater was carried out.

Abstract: Bridge pier collision avoidance system is a hot research topic. As the representative of the intelligent material, the Magnetorheological Grease has become one of the main research directions in the research of bridge pier collision due to its special mechanical properties and rheological properties. In this work, we present a bridge pier collision avoidance system using Magnetorheological Grease Material. Firstly, according to the characteristics of bridge pier collision, a series of Magnetorheological Grease Material are configured, and then the collision avoidance structure of the actual size of the bridge pier is given. The structure can be directly applied to the bridge pier collision avoidance. Secondly the experimental characteristics of the Magnetorheological Grease Material are given, and the experimental results are analyzed. The strong theoretical guidance and engineering basis were provided for the related scientific and technical workers and researchers.

Abstract: With the continuous development of science and technology, the function of the electrochemical biosensor is becoming more and more diversified. The fourth generation of enzyme-free glucose sensor because of its particular advantages has become one of research focuses in glucose sensor now. For all sorts of optimization also are not enzyme glucose as the new material was born has made great progress. Enzyme-free glucose sensors are becoming more and more an integral part of electrochemical research. This article summarizes the characteristics of all kinds of conventional materials of enzyme-free glucose sensor, the domestic and foreign general preparation methods of enzyme-free glucose sensors, the specific characterization of the electrode, its application fields, and prospects for future development.

Abstract: Nanostructured Cu-Ag alloys with bimodal grain size distribution were prepared and their tensile deformation behaviors were studied. The alloys were processed by hot isostatic pressing of blends of nanoand micrometer-sized powder particles. The microstructure of the alloys consisted of nanograins with an average grain size of 40 nm and coarse-grains with an average grain size of 30 um. The bimodal structured alloy exhibited high tensile strengths 522 MPa and a large plastic strain to failure approximately 30%. Simultaneously, Their tensile stress-strain curves displayed a long work-hardening region, and their tensile ductility increased with increasing coarse-grained volume fraction. The high strength primarily results from the contribution of nanograins, while the enhanced ductility may be attributed to the improved strain hardening capability by the presence of coarse grains.

Abstract: In this work, graphene quantum dots were simply and rapidly prepared by thermal decomposition of citric acid. The resulting graphene quantum dots shows good dispersion and high crystallinity, the sizes can be effectively adjusted by controlling the temperature of decomposition. The results indicate that with the increase of temperature, the size of GQDs increased from 2 nm to 12 nm. The effect of the size of graphene quantum dots on the optical properties were carefully studied. Based on the optical properties and electrochemical results, the HOMO and LUMO value of GQDs with different sizes were obtained and the band gap becomes smaller from 3.36 eV to 2.87 eV with the increase of size of GQDs, which provides a potential application in the field of optoelectronic devices.

Abstract: This work presents investigations on preparation of 20 wt. % Pt_0.5Pd_0.5/C nanoelectrocatalysts by electroless and their electrocatalytic properties. The 20 wt. % Pt_0.5Pd_0.5/C nanoelectrocatalysts were prepared by electroless successfully. The optimum experimental conditions of the main effect factors in preparing the PtPd nanoelectrocatalysts are [Pt²⁺ or Pd²⁺] =2-10g/L, [HCHO] =10-20g/L, temperature: 40-60°C, the dosage of protection reagent: 1-3 % of the platinum and palladium content, the agitation rate 400-500r/min. The characterization of 20 wt. % Pt_0.5Pd_0.5/C was performed with cyclic voltammetry (CV) and transmission electron microscope (TEM), respectively. Particles of PtPd are distributed symmetrically on C by TEM, of which are very small and the average granularity is less than 3nm. The nanoelectrocatalysts have high stabilization and lots of catalysis nuclei through CV.

Abstract: The magnesium hydroxide whiskers,its length being about 30μm and its diameter being about 3μm, was prepared by hydrothermal conditions. The effect of preparation technology, which includes the reaction temperature and reaction time, was discussed according to the results of XRD, TEM, and SEM. Moreover, the mechanism of the preparation of magnesium hydroxide whiskers was studied.

Abstract: In this paper, a new type of natural adsorption materials were prepared by spray granulation. The structure and properties of the product were characterized by scanning electron microscope analysis, N₂ adsorption desorption analysis, infrared analysis, X ray diffraction analysis, the rmogravimetric analysis. The results showed that: the best preparation conditions of the adsorption materials were as follows: the temperature was 59.21°C, the pressure was 0.28 Bar, and the rate was 14.15 ml/min. In addition, the natural materials had high porosity and specific surface areas , which was better for adsorption. The pore size was mainly concentrated between 13 ~ 28nm. Moreover, these materials had more functional groups. The decomposition temperature was 250°C,which resulted in better thermal stability. Consequently, the materials had better adsorption properties, and the materials will have better application prospect.

Abstract: In this paper,using water extraction acid sinking method to extract the active components of scutellaria baicalensis.Taking a certain amount of scutellaria baicalensis powder, adding water to boil, adding hydrochloric acid to the filtrate,through a series of steps,the effective components of scutellaria baicalensis could be obtained. Through infrared spectrum and mass spectrum analysis means,it was known that the effective components was baicalin.By using the grinding method, the chitosan and baicalin were mixed to prepare the mixture.Through the cutting of mice tail hemostasia test , the performance of the product was studied.The results showed that the performance of the mixture of chitosan and baicalin was better than that of chitosan,while chitosan and baicalin optimum ratio was 1: 0.8.

Abstract: Carboxymethyl chitosan (CAS) was obtained by carboxymethylation of chitosan (CS).The Ag⁺-CAS,TiO₂-CAS and Ag⁺-TiO₂-CAS were prepared by introducing AgNO₃ and nanometre TiO₂ solution into the product obtained the previous step. The structures of samples were characterized by IR, XRD, SEM etc. The properties of cruor and hemostasis were studied by biological experiment. The results showed that there were characteristic absorption peaks of carboxymethyl chitosan sodium salt around 3423cm^-1 and 1380cm^-1 in the IR spectra of modified carboxymethyl chitosan. The XRD showed it was metals Crystalline. The average diameter of CAS was about 14.8nm, the Ag⁺ was 143.5nm, nanometre TiO₂ was 267.2nm and all of them were homodisperse. The properties of crour and hemostasis of Ag⁺-TiO₂-CAS were superior to Ag⁺-CAS and TiO₂-CAS, while the Ag⁺-CAS and TiO₂-CAS were also have an advantage over CAS.