Papers by Keyword: Synthesis

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Authors: R.H.L. Garcia, Valter Ussui, Nelson Batista de Lima, Dolores Ribeiro Ricci Lazar
Abstract: The addition of alumina in a zirconia stabilized in a tetragonal phase matrix enhances ceramic hardness and inhibits the tetragonal → monoclinic phase transformation of zirconia when exposed to an aqueous environment. These characteristics are important for applications such as bioceramics and structural materials. For these purposes, the strict control of powder synthesis and the processing conditions are vital to tailor the ceramic characteristics. This work evaluates the influence of 20 wt% alumina in a Y-TZP matrix on powder characteristics, obtained by coprecipitation route, and calcined from 600 to 1200°C for 1 and 3 hours. The powders obtained were characterized by X-ray diffraction, scanning electronic microscopy, laser diffraction and gaseous adsorption (BET). The results reveal that presence of Al3+ inhibits the crystallization of composite at lower temperatures.
Authors: Feng Wang, Mu Sen Li
Abstract: Hydroxyapatite (HA) powders were directly synthesized in simulated body fluid (SBF) at 37°C, without the need for high-temperature calcified. These powders were found to contain trace amount of CO32-, Cl-, Na+ and K+ impurities, originated from the of SBF solutions during their deposition. The characterizations of the synthesized HA powders were performed by X-ray diffraction (XRD), Fourier-transformed infra-red spectroscopy (FTIR) and Transmission electron microscope (TEM). The experimental results showed that the HA synthesized by the SBF route might be more close to that human bone in structure and compositions. Furthermore, the processes flow for HA synthesis was optimized and the synthesized mechanism was also discussed.
Authors: Gui Fa Li, Shi Qiang Lu, Jun Wei Liu, Ping Peng
Abstract: Based on the method of LST/QST improved in the molecular orbital DMol3 program, with the aid of the minimum energy path (MEP) in the climbing image nudged elastic band (CI-NEB) method, the Oh-Al13 cluster is investigated under different synthesis process, i.e. Al6+Al7→Al13. The results show that: there are two stages in the synthesis reaction: the distortion stage and the configuration revolution stage. In the first stage, the metastable structures are forced to change into stable structures. In the configuration evolution stage, two different cases exist. For the synthesis of crystal clusters it is an automatic exothermic reaction if all reactants being of typical crystal symmetrical elements, i.e., Al6+Al7M®Oh-Al13. While an energy barrier must be overcome if one of reactants having fivefold or tenfold symmetrical axes, i.e.,Al6+Al7、Al6M+Al7 and Al6M+Al7M . So the five-symmetry structures are only appearing in rapidly solidified processes except crystallization processes.
Authors: Hao Zhang, Xi Jiang
Abstract: The recognition and sensing of biologically and environmentally important species has emerged as a significant goal in the field of chemical sensors in recent years1. Fluorogenic methods in conjunction with suitable probes are preferable approaches for the measurement of these analytes because fluorimetry is rapidly performed, is nondestructive, is highly sensitive, is suitable for high-throughput screening applications2,3. We synthesized rhodamine derivatives compounds by a Schiff base reaction.
Authors: Shan Shan Han, Jin Yun Xu, Guo Zheng, Yu Sun
Abstract: This first part of this paper will introduce the mechanical-dynamical properties of polysiloxane defoamer thoroughly. Defoamers or foam breakers are added to eliminate the existing foam and usually act on the outer surface of the foam because a bubble is a closed system and the defoamer can only reach the outer surfaces. Then, some of synthesis methods and compounds under real application conditions are given, such as synthesis of methyl hydrogen silicone oil, synthesis methods of polyether and compounds of polyether modified polysiloxane defoamer.
Authors: Qiu Ying Chen, Qi Wang
Abstract: A facile and effective route to the synthesis of different sulfonyl azides using the inexpensive NaN3 and common sulfonyl chlorides was reported, which could be further applied to the synthesis of sulfonamide-containing compounds.
Authors: Rui Lin, Gu Qiao Ding, Peng He, Jing Chen
Abstract: A facile method is proposed to synthesize carbon quantum dots (C-dots) from citric acid using concentrated sulfuric acid as carbonization reagents with temperature below 100 °C during the whole process. The prepared C-dots has a Gaussian distribution in its lateral size with the average value around 6.37 nm. High quality of the C-dots is revealed through the optical performances such as sharp band-edge absorption, typical absorption peak and nearly excitation-independent blue emissions. Further, the pH condition is found to have correlation on the strong and stable photoluminescence property.
Authors: Miao Wang, Si Yuan Xu, Yong Xin She, Mao Jun Jin, Fen Jin, Hua Shao, Jing Wang
Abstract: A simple and convenient method to make a novel material of DNA-coated magnetic-fluorescent composite particles was presented in this article. Hydrothermal synthesis was used for obtaining Fe3O4 magnetic nanoparticles. After modified by oleic acid, the nanoparticles were coated by the macromolecular shell, which came form the polymerization of ethyleneglycol dimethacrylate and methacrylic acid. With the help of ethylenediamine as linker molecules and the condensation effect of ethyl (dimethylaminopropyl) – carbodiimide and N-Hydroxysuccinimide (EDC/NHS) reaction system, salmon DNA were linked to the surface of the shell. After labeling a fluorescent dye Syber Green Ⅰ®, the magnetic-fluorescent composite particles were produced.
Authors: Yao Yu Ren, Chang Sheng Deng, De Sheng Ai, Jing Tao Ma, Qing Feng Zan, Jiang Rong Kong, Jing Ming Xu
Abstract: Pr-doped ceria solid solutions have attracted much attention as promising mixed electronic-ionic conductor and oxygen storage materials. However, little effort has been made to synthesize Pr-doped ceria with one-dimensional nanostructure. In this paper, Pr-doped ceria nanorods were prepared via a facile hydrothermal method using Pr(NO3)3, Ce(NO3)3 and NaOH as raw materials. X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED) indicated that the as-prepared Pr-doped ceria nanorods had a cubic fluorite structure, with the length around 200 ~ 400 nm and the diameters around 10 ~ 18 nm. The effect of alkaline concentration has been systematically studied and the results indicated that higher alkaline concentration was favorable for the formation of nanorods.
Authors: Xuan Qi, Zhong Tian Fu, Liang Li, Xiao Min Hu, Hong Bin Sun
Abstract: Abstract. Two applied synthesis techniques of bentazone were introduced including the disadvantages. Innovative adjustments were developed to eliminate the produce of waste water in isatoic anhydride route, and determined as: DMF as the solvent of o-amino-benzoyl isopropylamine preparation, based on certain treatments bentazone sodium salt solution as the product, soda lime as hydrolysis reagent to eliminate phosphorus oxychloride. With 95% recycling rate of 2-methyl pyridine, in the sodium salt aqueous solution, bentazone was prepared from isatoic anhydride with the yield of 85.5% and purity of 98%.
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