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Period-doubling and chaotic oscillations in the ferroin-catalyzed Belousov-Zhabotinsky reaction in a CSTR

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Science china Chemistry 2007年第2期50卷 205-211页

作者： ZONG ChunYan GAO QingYu WANG YuMei FENG JiaMin MAO ShanCheng ZHANG Lu School of Chemical engineering China University of Mining and TechnologyXuzhou 221008China

The ferroin-catalyzed Belousov-Zhabotinsky(BZ) reaction,the oxidation of malonic acid by acidic bromate,is the most commonly investigated chemical system for understanding spatial pattern forma-tion. Various oscillatory behaviors were found from such as mixed-mode and simple period-doubling oscillations and chaos on both Pt electrode and Br-ISE at high flow rates to mixed-mode oscillations on Br-ISE only at low flow rates. The complex dynamic behaviors were qualitatively reproduced with a two-cycle coupling model proposed initially by Gy?rgyi and Field. This investigation offered a proper medium for studying pattern formation under complex temporal dynamics. In addition,it also shows that complex oscillations and chaos in the BZ reaction can be extended to other bromate-driven nonlinear reaction systems with different metal catalysts.

关键词： Belousov-Zhabotinsky reaction period-doubling oscillations numerical simulation

Numerical simulation of excess-enthalpy combustion flame propagation of coal mine methane in ceramic foam

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mining Science and technology 2010年第2期20卷 248-253页

作者： SONG, Zhengchang LIN, Boquan school of mechanical engineering china university of mining & technologyxuzhou 221008china school of safety engineering china university of mining & technologyxuzhou 221008china

Based on the assumption of a local non-equilibrium of heat transfer between a solid matrix and gas,a mathematic model of coal mine methane combustion in a porous medium was established,as well the solid-gas boundary *** simulated numerically the flame propagation *** results show that the flame velocity in ceramic foam is higher than that of free laminar flows;the maximum flame velocity depends on the combined effects of a radiation extinction coefficient and convection heat transfer in ceramic foam and rises with an increase in the chemical equivalent *** radiation extinction coefficient cannot be used alone to determine the heat regeneration effects in the design of ceramic foam burners.

关键词： combustion ceramic foam coal mine methane numerical simulation flame propagation

Current oscillations during the electrochemical oxidation of sulfide in the presence of an external resistor

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Science china Chemistry 2008年第4期51卷 333-340页

作者： FENG JiaMin GAO QingYu LI Jun LIU Li MAO ShanCheng College of Chemical engineering China University of Mining and TechnologyXuzhou 221008China

The electrochemical oxidation of sulfide on a polycrystalline platinum electrode was studied under potentiostatic condition when an external resistor is in series with the working electrode. Only two os- cillatory regions can be obtained in the absence of the external resistance, but four oscillatory regions, including two new current oscillations, were found in this system by controlling the external resistance. It is demonstrated that three oscillatory regimes, which arise on the positive branch of current-potential curve, can be classified as HN-NDR (Hidden N-shaped Negative Differential Resistance) oscillators. For the first oscillatory region, various transient complex phenomena, which result from the change of the electrode/electrolyte interface by accumulation of adsorbed element sulfur on the electrode, have been observed. The dynamic behavior of NDR (Negative Differential Resistance) oscillations, appearing along with negative branch of polarization curve, can transform from oscillations into bistability with a sufficient large external resistance in series. Two oscillatory regions in high-potential region classified as HN-NDR type oscillations are separated by a saddle-loop bifurcation. They displayed a sequence of bursting oscillations and irregular oscillations, respectively. The electrochemical oxidation of sulfide provides a model system for studying complex dynamics and possible application in sulfur removal.

关键词： sulfide electrochemical oxidation series resistance bistability and oscillations mixed-mode and bursting oscillations

Control of stochastic spike motion in an excitable system via recycled noise

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Science china Chemistry 2011年第9期54卷 1504-1509页

作者： MA Juan GAO QingYu College of Chemical engineering China University of Mining and Technology Xuzhou 221008 China

The control effect of recycled noise,generated by the superposition of a primary Gaussian noise source and a secondary source with a constant delay,has been studied in an excitable FitzHugh-Nagumo *** mainly focus on the performance of noise-induced spike and coherence resonance in a parameter region sub-threshold to supercritical Hopf *** fixed noise intensity,simulations show that the coherence(quantitatively measured by R,which is defined as the mean value of the spike interval time T normalized to its mean square root) and the emission velocity of the noise-induced spikes exhibit damped oscillations with the variation of delay time,demonstrating a new kind of multi-resonance ***,the optimal delay times for resonance and the fast emission velocity are related to the inherent frequency of the *** seems that there are some synchronization effects between the dynamic character of the system and the delay time of recycled *** results give clear information about how one can control the coherence and emission velocity of the noise-induced spike in a rather effective way,by deliberately adjusting the delay time and the fraction of the secondary noise.

关键词： stochastic spike excitable recycled noise coherent resonance

Kinetic study on hydrolysis and oxidation of formamidine disulfide in acidic solutions

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Science china Chemistry 2012年第2期55卷 235-241页

作者： HU Ying FENG JiaMin LI YanWei SUN YanYan XU Li ZHAO YueMin GAO QingYu College of Chemical engineering China University of Mining and Technology Xuzhou 221008 China

Hydrolysis and oxidation of formamidine disulfide in acidic medium were investigated using high-performance liquid chro- matography （HPLC） and mass spectrometry （MS） at 25 ~C. By controlling the slow reaction rate and choosing appropriate mobile phase, HPLC provides the unique advantages over other methods （UV-Vis, chemical separation） in species tracking and kinetic study. In addition to thiourea and formamidine sulfinic acid, two unreported products were also detected in the hy- drolysis reaction. Mass spectrometry measurement indicates these two products to be formamidine sulfenic acid and thiocyan- ogen with mass weights of 92.28 and 116,36, respectively. In the oxidation of formamidine disulfide by hydrogen peroxide, besides thiourea, formamidine sulfenic acid, formamidine sulfinic acid, thiocyanogen and urea, formamidine sulfonic acid and sulfate could be detected. The oxidation reaction was found to be first order in both forrnamidine disulfide and hydrogen per- oxide. The rate constants of hydrolysis and oxidation reactions were determined in the pH range of 1.5-3.0. It was found both rate constants are increased with the increasing of pH. Experimental curves of different species can be effectively simulated via a mechanism scheme for formamidine disulfide oxidation, including hydrolysis equilibrium of formamidine disulfide and irre- versible hydrolysis of formamidine sulfenic acid.

关键词： formamidine disulfide hydrolysis oxidation HPLC-MS

Effective remediation of organic-metal co-contaminated soil by enhanced electrokinetic-bioremediation process

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Frontiers of Environmental Science & engineering 2021年第6期15卷 221-230页

作者： Fu Chen Qi Zhang Jing Ma Qianlin Zhu Yifei Wang Huagen Liang Low Carbon Energy Institute China University of Mining and TechnologyXuzhou 221008China School of Environmental Science and Spatial Informatics China University of Mining and TechnologyXuzhou 221008China School of Public Policy and Management China University of Mining and TechnologyXuzhou 221116China

This work investigates the influence of electrokinetic-bioremediation(EK-BIO)on remediating soil polluted by persistent organic pollutants(POPs)and heavy metals(mainly Cu,Pb and Ni),originated from electronic waste recycling *** results demonstrate that most of POPs and metals were removed from the *** than 60%of metals and 90%of POPs in the soil were removed after a 30-day EK-BIO remediation assisted by citrate.A citrate sodium concentration of 0.02 g/L was deemed to be suitable because higher citrate did not significantly improve treatment performance whereas increasing dosage *** increased soil electrical current and electroosmotic *** remediation,metal residues mainly existed in stable and low-toxic states,which could effectively lower the potential hazard of toxic metals to the surrounding environment and ***-BIO treatment influenced soil microbial counts,dehydrogenase activity and community structure.

关键词： Electrokinetic Co-contamination Debromination

Microstructure and Tribological Properties of Plasma Nitriding Cast CoCrMo Alloy

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Journal of Materials Science & technology 2012年第1期28卷 60-66页

作者： Qingliang Wang Chuanhui Huan Lei Zhang School of Material Science and engineering China University of Mining&TechnologyXuzhou 221116China College of Electro-mechanical engineering Xuzhou Institute of TechnologyXuzhou 221008China

A medical cast CoCrMo alloy was coated by plasma nitriding process to enhance the wear resistance. The microstructures, phases and micro-hardness of nitrided layers were investigated by atomic force microscopy （AFM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and micro-hardness. Tribological prop- erties were investigated on a pin-on-disc wear tester under 25% bovine serum solutions. The experimental results showed that plasma nitriding was a promising process to produce thick, hard and wear resistant layers on the surface of CoCrMo alloy. The harder CrN and Cr2N phases formed on the plasma nitrided layer with the compact nano-crystalline structure. Compared with the untreated sample, all nitrided samples showed the lower wear rates and higher wear resistance at different applied loads and nitriding temperatures. It was concluded that the improvement of wear resistance could be ascribed to the formation of thicker and harder nitrided layers with the specific microstructures on nitrided surfaces.

关键词： CoCrMo alloy Plasma nitrlding Microstructure Tribology

Study on Synthesis and Gas Sensitivity of SnO2 Nanobelts

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Chinese Physics Letters 2006年第4期23卷 1026-1028页

作者：应鹏展倪自丰修伟杰贾良菊罗勇 School of Materials Science and engineering China University of Mining and Technology Xuzhou 221008

Tin dioxide （SnO2 ） nanobelts have been successfully synthesized in bulk quantity by the CVD process based on the thermal evaporation of tin powders. The x-ray diffraction analysis indicates that the nanobelts are the tetragonal futile structure of SnO2. Scanning electron microscopy and transmission electron microscopy observations reveal that the nanobelts are uniform. The selected-area electron diffraction analysis demonstrates that the nanobelts are single crystals. The energy dispersive x-ray analysis of the nanobelt shows that the nanobelts are composed of Sn and O, Gas-sensing components have been manufactured with prepared SnO2 nanobelts. Their performance indicates that SnO2 nanobelts have high sensitivity and selectivity to liquefied petroleum gas with fairly good response-recovery characteristic and stability at 220℃.

关键词： TIN OXIDE NANORIBBONS NANOWIRES GROWTH

Stratum energy of coal-bed gas reservoir and their control on the coal-bed gas reservoir formation

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Science china Earth Sciences 2007年第9期50卷 1319-1326页

作者： WU CaiFang QIN Yong FU XueHai Department of Earth Resources and Geosciences China University of Mining & Technology Xuzhou 221008 China Department of Earth Resources and Geosciences China University of Mining & Technology Xuzhou 221008 China Department of Earth Resources and Geosciences China University of Mining & Technology Xuzhou 221008 China

Stratum energy of coal-bed gas reservoir, including coal-radix flexibility energy, groundwater flexibility energy and gas flexibility energy (hereinafter "three energy"), depends on the energy homeostasis system, the core process of which is the effective transfer of energy and the geological selective process. Combining with the mechanics experimentations of coal samples, different flexibility energy has been analyzed and researched quantificationally, and a profound discussion to their controls on the coal-bed gas reservoir formation has been made. It is shown that when gas reservoir is surrounded by edge water and bottom water, the deposited energy in the early phase of forming gas reservoir is mostly coal-radix and gas flexibility energy, but the effect of groundwater flexibility energy increases while water-body increases. The deposited energy in the middle and later phase of forming gas reser voir is mostly gas flexibility energy, which is greater than 80% of all deposited energy. In the whole process, larger groundwater body exerts greater influences on gas accumulation. The paper indicated that higher stratum energy is more propitious to forming coal-bed gas reservoir. And higher coal-radix flexibility energy and gas flexibility energy are more propitious to higher yield of gas reservoirs, while higher groundwater flexibility energy is more propitious to stable yield of gas reservoirs. Therefore, the key to evaluating the coal-bed gas reservoir formation is the stratum energy of coal-bed gas reservoir.

关键词： coal-bed reservoir, flexibility energy, coal-radix flexibility energy, groundwater flexibility energy, gas flexibility energy, coal-bed gas reservoir formation