Effects of noise on rate oscillations during CO oxidation on Pt（110） surface were investigated, both theoretically and numerically, by focusing on the interplay of internal noise （IN） due to stochasticity in react...Effects of noise on rate oscillations during CO oxidation on Pt（110） surface were investigated, both theoretically and numerically, by focusing on the interplay of internal noise （IN） due to stochasticity in reaction events, and external noise （EN） resulting from parameter perturbation. The surface is divided into cells of variable size which are assumed to be well mixed, and we consider the behavior inside a single cell. Attention is paid to parameter regions subthreshold of the deterministic Hopf bifurcation, where noise can induce stochastic oscillations, the signal-to-noise ratio （SNR） of which shows a maximum with the variation of noise intensity, known as coherent resonance （CR）. By stochastic normal theory, we show that IN and EN contribute in a weighted additive way to an effective noise that lead to CR, such that SNR shows a ridge shape in the D-1/√N plane, where D and 1/√N measures the strength of EN and IN, respectively. It is shown that for too large IN （EN）, CR behavior with EN （IN） no longer exists. Numerical simulations show good agreements with the theoretical results.展开更多
A series of acetate ionic liquids were synthesized using a typical two‐step method.The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and...A series of acetate ionic liquids were synthesized using a typical two‐step method.The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and alcohols under mild conditions.The basic strengths of the ionic liquids were evaluated by determination of their Hammett functions,obtained using ultraviolet‐visible spectroscopy,and the relationship between their catalytic activities and basicities was established.The catalytic efficiencies of the ionic liquids were higher than that of the traditional basic catalyst NaOH.This can be attributed to the involvement of a novel reaction mechanism when these ionic liquids are used.A possible electrophilic‐nucleophilic dual activation mechanism was proposed and confirmed using electrospray ionization quadrupole time‐of‐flight mass spectrometry.In addition,the effects of significant reaction parameters such as concentration of catalyst,molar ratio of alcohol to propylene oxide,reaction temperature,and steric hindrance of the alcohol were investigated in detail.展开更多
O-nitro-phenol wastewater which contains refractory organic matters can not be degraded by conventional biological methods. In this work, o-nitro-phenol wastewater was effectively treated using magnetization-enhanced ...O-nitro-phenol wastewater which contains refractory organic matters can not be degraded by conventional biological methods. In this work, o-nitro-phenol wastewater was effectively treated using magnetization-enhanced oxidation by NaCIO solutions. The pollutant concentrations in wastewater were 250 mg/L o-nitro-phenol, 2,000 mg/L CODcr and 150 times color. The experimental results show that, using the method in this work, 94.4% o-nitro-phenol, 94.2% CODCr and 100% color can be removed at pH 6, 200 mg charcoal, 8 mL oxidizer, 5 min reaction time in 1000 mL wastewater. The treatment can be enhanced under magnetic field. CODCr and o-nitro-phenol removal can keep unchanged while the reaction time can be reduced to 3 min when the intensity of magnetic field was 60 mT.展开更多
文摘Effects of noise on rate oscillations during CO oxidation on Pt（110） surface were investigated, both theoretically and numerically, by focusing on the interplay of internal noise （IN） due to stochasticity in reaction events, and external noise （EN） resulting from parameter perturbation. The surface is divided into cells of variable size which are assumed to be well mixed, and we consider the behavior inside a single cell. Attention is paid to parameter regions subthreshold of the deterministic Hopf bifurcation, where noise can induce stochastic oscillations, the signal-to-noise ratio （SNR） of which shows a maximum with the variation of noise intensity, known as coherent resonance （CR）. By stochastic normal theory, we show that IN and EN contribute in a weighted additive way to an effective noise that lead to CR, such that SNR shows a ridge shape in the D-1/√N plane, where D and 1/√N measures the strength of EN and IN, respectively. It is shown that for too large IN （EN）, CR behavior with EN （IN） no longer exists. Numerical simulations show good agreements with the theoretical results.
基金supported by the One Hundred Talent Program of CASthe National Natural Science Foundation of China Petroleum & Chemical Corporation Joint Fund(U1662129)+1 种基金the National Natural Science Foundation of China(91434203)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(QYZDY-SSW-JSC011)~~
文摘A series of acetate ionic liquids were synthesized using a typical two‐step method.The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and alcohols under mild conditions.The basic strengths of the ionic liquids were evaluated by determination of their Hammett functions,obtained using ultraviolet‐visible spectroscopy,and the relationship between their catalytic activities and basicities was established.The catalytic efficiencies of the ionic liquids were higher than that of the traditional basic catalyst NaOH.This can be attributed to the involvement of a novel reaction mechanism when these ionic liquids are used.A possible electrophilic‐nucleophilic dual activation mechanism was proposed and confirmed using electrospray ionization quadrupole time‐of‐flight mass spectrometry.In addition,the effects of significant reaction parameters such as concentration of catalyst,molar ratio of alcohol to propylene oxide,reaction temperature,and steric hindrance of the alcohol were investigated in detail.
文摘O-nitro-phenol wastewater which contains refractory organic matters can not be degraded by conventional biological methods. In this work, o-nitro-phenol wastewater was effectively treated using magnetization-enhanced oxidation by NaCIO solutions. The pollutant concentrations in wastewater were 250 mg/L o-nitro-phenol, 2,000 mg/L CODcr and 150 times color. The experimental results show that, using the method in this work, 94.4% o-nitro-phenol, 94.2% CODCr and 100% color can be removed at pH 6, 200 mg charcoal, 8 mL oxidizer, 5 min reaction time in 1000 mL wastewater. The treatment can be enhanced under magnetic field. CODCr and o-nitro-phenol removal can keep unchanged while the reaction time can be reduced to 3 min when the intensity of magnetic field was 60 mT.
