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排序方式: 共有2140条查询结果,搜索用时 15 毫秒
91.
Fengfeng Gao Jinhua Luo Xuefeng Zhang Xiaogang Hao Guoqing Guan Zhong Liu Jun Li Qinglong Luo 《中国化学工程学报》2022,49(9):161-169
Effective extraction and regeneration of radioactive iodide is one of urgent concerns for the safe utilization of nuclear energy. As a novel environmentally benign ion separation technique, electrochemically switched ion extraction (ESIE) process can be applied for effective capture and recovery of iodide ions (I-). Herein, a novel kelp seaweed-like core/shell I- imprinted polypyrrole@bismuth oxyiodide (PPy/I-@BiOI) composite film is successfully prepared for the selective I- capture in the ESIE system. It is found that the I- can be easily trapped in the PPy/I-@BiOI film after I- is in situ desorbed from the film by an electrochemical reduction process since it offers particular electroactive binding sites for I- extraction. The I- imprinted PPy/I-@BiOI film displays an extraction capacity as high as 325.2 mg·g-1 for I- with favorable stability. In particular, the extraction and desorption of I- is achieved by adjusting the redox potential and the pristine PPy/I-@BiOI film can be regenerated and reused for multiple times without decrease in extraction capacity. It is expected that such a PPy/I-@BiOI film would be useful as an electrochemically switched renewable extractor that could capture and regenerate I- from radioactive water. 相似文献
92.
This paper considers the separation in 2-period double round robin tournaments (2P-DRRTs) with minimum breaks. The separation is a lower bound on the number of slots between the two games with the same opponents. None of known schemes provides 2P-DRRTs with minimum breaks and a positive separation. We first propose a new scheme to generate 2-separation 2P-DRRTs with minimum breaks, based on single round robin tournaments (SRRTs) with minimum breaks which have the last break in the third slot from the end. Our experiment results show that such SRRTs exist for 8-68 teams. Secondly, we consider maximizing the separation in general 2P-DRRTs with minimum breaks by integer programming and constraint programming, respectively. The two approaches of direct formulation and “first-break, then-schedule” decomposition are presented and compared. We obtain the maximum separation for up to 14 teams. Furthermore, we consider the application with place constraints to show the flexibility and efficiency of scheduling 2P-DRRTs with minimum breaks and a positive separation. 相似文献
93.
The main purpose of this work was the modification of NaX nanozeolite using copper oxide nanoparticles and various monovalent cations such as K~+, Cs~+, and Ag~+in order to make the negatively charged zeolite surface accessible for anionic forms of uranium which are the most dominant species of uranium in the contaminated radioactive waters at natural p H. Various methods such as the X-ray fluorescence(XRF), X-ray powder diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FT-IR), and atomic absorption spectroscopy(AAS) were used to characterize the final synthesized absorbents. Batch technique was used to study the adsorption behavior of uranium ions from polluted drinking water by Na X nanozeolite and its modified forms. In order to better understand the performance of them, the results were compared with those that were obtained for synthesizing bulk NaX zeolite and Na-form of clinoptilolite natural zeolite. Preliminary results indicated that uranium sorption increased as the loading level of CuO nanoparticles on NaX nanozeolite increased from 2.1 wt% to 11.2 wt%. In addition,from the obtained data, an increase in uranium removal efficiency resulted as charge/ionic radius ratio of exchanged cation decreased. Also, the effect of contact time, solid–liquid ratio, initial concentration and temperature on the adsorption process was studied. It is worth mentioning that, in this study, the sorption of uranium was performed under natural conditions of pH and the presence of competing cations and anions which are available in drinking waters. 相似文献
94.
Emulsion droplet size is information of paramount importance in the design and evaluation of oil–water separators. This paper describes the application of a technique for in situ determination of water droplet diameter distribution (DDD) in actual production scenarios. We discuss the DDD and water content measurements in emulsions obtained during normal operation and plant upsets including variations of the demulsifier chemical dosage or tripping of the electrostatic coalescer grids inside a large dehydrator vessel operated on a crude oil production field in Saudi Arabia. It is demonstrated that DDD data can provide a detailed understanding of the oil–water separation phenomena occurring inside the dehydrator vessel, which helped in planning process recovery strategies in the event of a plant upset. 相似文献
95.
Mixtures of various proportions of a polyolester and a polyphenylether (5P4E) have been prepared and their elastohydrodynamic film thicknesses measured in a rolling point contact. It has been found that small amounts of polyolester reduce the film thickness of 5P4E far more than viscosity values would predict. One explanation for this is that the pressure-viscosity coefficient of 5P4E is very sensitive to small amounts of polyolester, and is reduced by a factor of five with only 20 percent of polyolester. This might result from the ester acting as a plasticizer in reducing the glass transition temperature of 5P4E. Alternatively, 5P4E may be behaving in a non-Newtonian fashion over the range of shear rates studied. 相似文献
96.
Deniz Akta Uygun A. Alev Karagzler Sinan Akgl Adil Denizli 《Materials science & engineering. C, Materials for biological applications》2009,29(7):2165-2173
N-Methacryloyl-l-phenylalanine (MAPA) containing poly(2-hydroxyethylmethacrylate) based magnetic [mag-poly(HEMA–MAPA)] nanobeads was prepared for lysozyme purification form chicken egg white. MAPA was synthesized by reacting methacryloyl chloride with l-phenylalanine methyl ester and provided hydrophobic functionality to the nanobeads. Size of mag-poly(HEMA–MAPA) nanobeads was 386 nm and obtained by surfactant free emulsion polymerization of HEMA and MAPA having a specific surface area of 580 m2/g. Mag-poly(HEMA–MAPA) nanobeads were characterized by FTIR, AFM, TEM, ESR, and elemental analysis. Lysozyme adsorption experiments were investigated under different conditions in batch system (i.e., medium pH, protein concentration, temperature, salt type). Lysozyme adsorption capacity of mag-poly(HEMA) and mag-poly(HEMA–MAPA) nanobeads from aqueous solutions was estimated as 24 and 517 mg/g, respectively. Lysozyme molecules were desorbed with 50% ethylene glycol solution with 98% recovery. It was observed that mag-poly(HEMA–MAPA) nanobeads can be used without significant decrease in lysozyme adsorption capacity after ten adsorption–desorption cycles. Mag-poly(HEMA–MAPA) nanobeads was used for the purification of lysozyme from chicken egg white. Purity of lysozyme was estimated by SDS-PAGE. 相似文献
97.
98.
提供了一种新的方法来分离二甲苯异构体-盐效应法。实验最重要的改进是在普通精馏中采用盐加溶剂。从分离结果看,利用盐效应将二甲苯分离是完全可能的。 相似文献
99.
本文研究了在氢氟酸溶液中以氯化亚汞及硫化汞作载体共沉淀分离微量稀土的方法。研究结果表明微克量稀土能与大量铁、铝、钼、铬、镍等定量分离。10μg稀土氧化物能与1000mgFe(Ⅱ)定量分离。 相似文献
100.