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Accelerated Simulation Study of Space Charge Effects in Quadrupole Ion Traps Using GPU Techniques 总被引:1,自引:0,他引:1
Xingchuang Xiong Wei Xu Xiang Fang Yulin Deng Zheng Ouyang 《Journal of the American Society for Mass Spectrometry》2012,23(10):1799-1807
Space charge effects play important roles in the performance of various types of mass analyzers. Simulation of space charge effects is often limited by the computation capability. In this study, we evaluate the method of using graphics processing unit (GPU) to accelerate ion trajectory simulation. Simulation using GPU has been compared with multi-core central processing unit (CPU), and an acceleration of about 390 times have been obtained using a single computer for simulation of up to 105 ions in quadrupole ion traps. Characteristics of trapped ions can be investigated at detailed levels within a reasonable simulation time. Space charge effects on the trapping capacities of linear and 3D ion traps, ion cloud shapes, ion motion frequency shift, mass spectrum peak coalescence effects between two ion clouds of close m/z are studied with the ion trajectory simulation using GPU. 相似文献
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Antibiotics, once being released into the environment, become recalcitrant organic pollutants, which pose a potential risk to ecological balance and human health. In this study, a Z-scheme heterojunction of bismuth oxyiodide (BiOI)/exfoliated g-C3N4 (BiOI/ECN hereafter) was synthesized by the combination of thermal exfoliation of g-C3N4 and chemical precipitation of BiOI for efficient photocatalytic degradation of tetracycline in aqueous solutions under visible light irradiation. The optimized BiOI/ECN delivered an outstanding degradation rate at circa 0.0705 min?1, which was 10 times higher than that of the bulk g-C3N4. The photocatalytic degradation efficiency of tetracycline remained almost unchanged in a pH range of 3–11, and the BiOI/ECN displayed an excellent photostability upon recycled usage. The photocatalytic mechanism of tetracycline was ascribed to the main reactive oxidation species of photogenerated holes and superoxide radicals. In addition, the possible degradation pathways of tetracycline were investigated by HPLC-MS to identify intermediates. The toxicity of photocatalytic-generated intermediates of tetracycline was found significantly alleviated according to the calculation of quantitative structure–activity relationship prediction. This work not only provides an attractive photocatalyst for the removal of tetracycline but also opens a new avenue for rational design of Z-scheme heterojunction composites for tetracycline degradation. 相似文献
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Yuan Wang Xuemei Liu Quyun Chen Tian C. Zhang Like Ouyang Shaojun Yuan 《Materials Today Chemistry》2022
Addressing arsenite pollution in groundwater has drawn great attention. It is attractive to pre-oxidize highly mobile As(III) to relatively low-toxic As(V) with a subsequent adsorption separation process. Herein, BiOI anchoring on γ-Fe2O3 is performed to synthesize BiOI/γ-Fe2O3 core–shell nanoparticles for efficient removal of As(III) via a simultaneous photocatalytic oxidization–adsorption process. The physical and chemical structures of BiOI/γ-Fe2O3 are investigated by transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction measurements. The photoluminescence and electron spin resonance (ESR) characterization were employed to ascertain the possible reaction mechanism of visible-light-driven photocatalytic oxidation of As(III). Such BiOI/γ-Fe2O3 delivers a superior As(III) removal capability under visible light irradiation with an arsenic removal efficiency of 99.8% within 180 min, higher than those of BiOCl/γ-Fe2O3 (81.7%) and BiOBr/γ-Fe2O3 (98.9%). The optimal BiOI/γ-Fe2O3 (molar ratio of 2:1) is obtained by rationally adjusting the molar ratio of BiOI to γ-Fe2O3. The as-synthesized BiOI/γ-Fe2O3 performs well in a wide pH range of 2–8. Only coexisting PO43? anions have a significant effect on the As(III) removal. The free radical trapping experiment and ESR results demonstrate that the ?O2? and h+ are the main active substances for the photocatalytic oxidation of As(III) on BiOI/γ-Fe2O3. This work not only gives a novel magnetic core–shell nanoparticle photocatalyst for efficient photocatalytic oxidation and adsorption of As(III) but also offers a new strategy to rationally design BiOX for its related practical applications. 相似文献
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采用高效毛细管电泳法分离两对D-氨基酸取代的胸腺五肽类似物。对影响分离的缓冲液pH值、电泳温度、电泳电压等进行了系统的研究。用含20mmol/L2,6-二甲基-β-环糊精(DM-β-CD),40mmol/L磷酸盐缓冲液(Ⅰ:pH6.03;Ⅱ:pH5.05)作运行缓冲液,柱温15℃,电压20kV,使样品获得基线分离,取得了满意的分离结果。结果显示,两组样品的D-氨基酸取代物均比L-氨基酸取代物出峰早,提示D-氨基酸取代物的电泳移动速度较快,与DM-β-CD的结合稳定性较L-氨基酸取代物弱。 相似文献
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Yang Wu Qing Ma Xiangrong Song Yu Zheng Wen Ren Jinkun Zhang Liang Ouyang Fengbo Wu Gu He 《Journal of polymer science. Part A, Polymer chemistry》2012,50(21):4532-4537
A novel amphiphilic poly(ethylene glycol)‐block‐poly(γ‐cholesterol‐L ‐glutamate) (mPEG–PCHLG) diblock copolymer has been synthesized. The mPEG–PCHLG copolymer has good biocompatibility and low toxicity. The mPEG–PCHLG copolymers could aggregate into nanoparticles with PCHLG blocks as the hydrophobic core and PEG blocks as the hydrophilic shell through emulsion solvent evaporation method. The copolymers were characterized by nuclear magnetic resonance spectroscopy, mass spectrum, Fourier transform infrared spectroscopy, and gel permeation chromatography. The particle sizes, size distributions, and zeta potentials of nanoparticles can also be determined by dynamic light scattering and transmission electron microscopy. This work provides a new and facile approach to prepare amphiphilic block copolymer nanoparticles with controllable performances. This novel copolymer may have potential applications in drug delivery and bioimaging applications.© 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献