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51.
Two new functionalized tetraphenylethene-based dyes were synthesized, and the enhanced AIE and mechanochrmic properties were evaluated upon grinding-fuming with the transformation from crystal forms to irregular amorphous forms. 相似文献
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Yang Zhirong Qu Timing Feng Feng Wang Linli Feng Pingfa 《Journal of Sol-Gel Science and Technology》2021,99(1):13-24
Journal of Sol-Gel Science and Technology - Wrinkling morphology could be utilized in various sensors because of its large specific surface area depending on the amplitude (A) of the wrinkles. The... 相似文献
53.
Cheng Tao Li Weilong Yu Baozhi He Mi Cao Linli Li Xinghua Zheng Xinliang Ren Zhaoyu 《Ionics》2017,23(11):3203-3210
Ionics - The design and optimization of electrode materials are critically important for the development of high-performance supercapacitors. Herein, hollow Fe2O3 nanotubes supported on... 相似文献
54.
A drug stability experiment accelerated by compressed oxygen was established. The stability of 10% ascorbic acid solution as a model was studied and the kinetic parameters were obtained with the newly established experimental method. Because ascorbic acid degrades under both anaerobic and aerobic conditions, the total rate constant k(total) can be expressed as: k(total)=k(anaerobic) + k(aerobic), where k(anaerobic) and k(aerobic) are the rate constants of anaerobic and aerobic degradations, respectively. The k(anaerobic) can be expressed as k(anaerobic) = A(anaerobic) x exp(-E(a,anaerobic)/RT) according to Arrhenius equation, and the k(aerobic) was found to be k(aerobic) = A(aerobic) x exp(-E(a,aerobic)/RT) x p(O2) in our study. 相似文献
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Magnetic graphene oxide as adsorbent for the determination of polycyclic aromatic hydrocarbon metabolites in human urine
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Detection of monohydroxy polycyclic aromatic hydrocarbons metabolites in urine is an advisable and valid method to assess human environmental exposure to polycyclic aromatic hydrocarbons. In this work, novel Fe3O4/graphene oxide composites were prepared and their application in the magnetic solid‐phase extraction of monohydroxy polycyclic aromatic hydrocarbons in urine was investigated by coupling with liquid chromatography and mass spectrometry. In the hybrid material, superparamagnetic Fe3O4 nanoparticles provide fast separation to simplify the analytical process and graphene oxide provides a large functional surface for the adsorption. The prepared magnetic nanocomposites were characterized by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. The experimental conditions were optimized systematically. Under the optimal conditions, the recoveries of these compounds were in the range of 98.3–125.2%, the relative standard deviations ranged between 6.8 and 15.5%, and the limits of detection were in the range of 0.01–0.15 ng/mL. The simple, quick, and affordable method was successfully used in the analysis of human urinary monohydroxy polycyclic aromatic hydrocarbons in two different cities. The results indicated that the monohydroxy polycyclic aromatic hydrocarbons level in human urine can provide useful information for environmental exposure to polycyclic aromatic hydrocarbons. 相似文献
56.
Yisheng ye Zhengquan Pan Linxi Zhang Linli He Agen Xia Haojun Liang 《Journal of Polymer Science.Polymer Physics》2010,48(17):1873-1881
The effects of applied magnetic field on the system composed of polymer brushes and magnetic particles are studied by means of Monte Carlo simulation. The direction of the applied magnetic field is chosen to be perpendicular to the substrate plane. Polymer brushes and magnetic particles are attracted to each other. The average heights of polymer brushes depend not only on the strength of applied magnetic field (H) but also on the brush grafting density (σ) and the chain length (N). The applied magnetic field influences the arrangement of magnetic particles, and in turn, the arrangement of magnetic particles affects the spatial distribution of polymer brush monomers. When the strength of the magnetic field is increased, the average height of polymer brushes will be increased accordingly. The reason is that the orientations of the magnetic moments of particles must be along the magnetic field direction, and this leads polymer brushes to rearrange along the magnetic field direction. At the same time, the chain length and the grafting density of polymer brushes have also effects on the properties of the magnetic particles, such as the magnetic particles distribution, magnetic susceptibility, and pair correlation functions. Comparisons with the experimental ones are also made, and this investigation can provide some insights into statistical properties of magnetic particle‐loaded brushes induced by external magnetic field. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1873–1881, 2010 相似文献
57.
The mesoporous N, S-codoped TiO2(B) nanobelts are synthesized via hydrothermal synthesis and post-treatment, and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption measurements (BET), X-ray photoelectron spectra (XPS), and UV-vis diffuse reflectance spectra (DRS). The results show that the prepared samples are mesoporous structured and exhibit stronger absorption in the visible light region with red shift in the absorption edge. The photocatalytic activity of N, S-codoped mesoporous TiO2(B) nanobelts is evaluated by the photocatalytic photodegradation of potassium ethyl xanthate (KEX) under visible light irradiation. It is found that the photocatalytic activity of the prepared samples increases with increasing the molar ratio of thiourea to Ti (R). At R = 3, the photocatalytic activity of the N, S-codoped TiO2(B) sample TBLTS-3 reaches a maximum value. With further increasing R, the photocatalytic activity of the sample decreases. The high photocatalytic activity of N, S-codoped TiO2(B) nanobelts can be attributed to the balance between strong absorption in visible light region and low recombination rate of electron/hole pairs. 相似文献
58.
Three mononuclear vanadium complexes containing aromatic 1, 2‐diols (catechol and naphthalene‐2, 3‐diol) ligands,[VIVO(cat)2][1, 3‐HPDA]2 · CH3OH ( 1 ), [VIVO(N‐2, 3‐D)2][1, 3‐H2PDA] ( 2 ), and [VVO2(N‐2, 3‐D)(1, 3‐HPDA)] · 1, 3‐PDA ( 3 ) (cat = catechol, N‐2, 3‐D = naphthalene‐2, 3‐diol, 1, 3‐PDA = 1, 3‐propanediamine) were synthesized and characterized by X‐ray diffraction, IR and UV/Vis spectroscopy, and cyclovoltammetry. X‐ray analysis reveals that the spatial frameworks of complexes 1 – 3 are all constructed by hydrogen bonds donated by [1, 3‐HnPDA]n+ (n = 1, 2) cation, forming distinct chain structures. Complexes 1 and 2 are both in the non‐chiral form of VO(L)2, but 2 crystallizes in the chiral space group (P6522), due to the symmetry element of spiral axis, whereas complex 3 contains both enantiomers of chiral VO2(L1)(L2) units, but crystallizes in the non‐chiral space group (P$\bar{1}$ ). The electrochemical behavior of the three complexes is studied in comparison with that of the free ligands. Complex 1 shows a pair of potentials assigned to the redox behavior of vanadium, while complexes 2 and 3 exhibit no such redox potentials. Pharmaceutical screening of complexes 1 – 3 were carried out against three representative cancer cell lines: A‐549 (lung cancer), Bel‐7402 (liver cancer) and HCT (colonic cancer) by MTT [3‐(4, 5‐dimethylthiazoyl‐2‐yl)‐2, 5‐diphenyltetrazolium bromide] assay. The results show that the vanadium‐catechol complex 1 exhibits more obvious anti‐proliferating effects against the three cell‐lines, whereas the two vanadium‐N‐2, 3‐D complexes 2 and 3 basically display no such effects. 相似文献
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A simple and controlled method of preparing uniform Ag midnanoparticles on Tollens-soaked silica spheres 总被引:1,自引:0,他引:1
Chen Z Chen X Zheng L Gang T Cui T Zhang K Yang B 《Journal of colloid and interface science》2005,285(1):146-151
Ag midnanoparticles (midnanoparticles are those particles whose diameters are in the range from 20 to 80 nm) with average size of 30-50 nm and tunable packing densities were formed on the surface of preformed Tollens-soaked silica spheres by a simple and controlled method. The process mainly involved two steps. In the first step the absorption of Ag(NH3)2(+) ions occurred on the silica spheres and in the second step Ag(NH3)2(+) ions on the silica spheres were reduced to Ag midnanoparticles in the presence of glucose solution. The amount of Ag midnanoparticles on the silica spheres could easily be tuned by varying the washing times in the process of preparing the Tollens-soaked silica spheres. The washing process also effectively avoided the reduction of Ag(NH3)2(+) ions and the nucleation of Ag particles in solution and easily produced more uniform Ag midnanoparticles on the silica spheres. Attributing to the uniform Ag midnanoparticles, the Ag midnanoparticle-coated silica spheres show unique optical properties in the UV-vis absorption spectra. The resulting Ag midnanoparticle-coated silica spheres were characterized with transmission electron microscopy, UV-vis-IR recording spectrophotometry, and X-ray photoelectron spectroscopy. 相似文献