中南大学学报·社会科学版杂志 CSSCI南大期刊 北大期刊

中南大学学报·社会科学版 2017年第08期杂志 文档列表

Electrocatalytic behaviour of Ni and NiCu alloy modified glassy carbon electrode in electro-oxidation of contraflam1703-1712

摘要：The electrocatalytic oxidation of contraflam was investigated in alkaline solution on nickel and nickel–copper alloy modified glassy carbon electrodes(GC/Ni and GC/NiCu). We prepared these electrodes by galvanostatic deposition and the surface morphologies and compositions of electrodes were determined by energy-dispersive X-ray(EDX) and scanning electron microscopy(SEM). Cyclic voltammetry and chronoamperometric methods were employed to characterize the oxidation process and its kinetics. Voltammetric studies exhibit one pair of well-defined redox peaks, which is ascribed to the redox process of the nickel and followed by the greatly enhanced current response of the anodic peak in the presence of contraflam and a decrease in the corresponding cathodic current peak. This indicates that the immobilized redox mediator on the electrode surface was oxidized contraflam via an electrocatalytic mechanism. The catalytic currents increased linearly with the concentration of contraflam in the range of 0.25– 1.5 mmol/L. The anodic peak currents were linearly proportional to the square root of scan rate. This behaviour is the characteristic of a diffusion-controlled process. The determination of contraflam in capsules is applied satisfactorily by modified electrode.

Elasticity under pressure and thermal property of Mg2La from first-principles calculations1713-1719

摘要：The elastic properties, thermodynamic and electronic structures of Mg2La were investigated by using first-principles. The calculated results show that pressure affects the elastic constants of C11 more than that of C12 and C44. Specifically, higher pressure leads to greater bulk modulus（B）, shear modulus（G）, and elastic modulus（E）. We predict B/G and anisotropy factor A based on the calculated elastic constants. The Debye temperature also increases with increasing pressure. Based on the quasi-harmonic Debye model, we examined the thermodynamic properties. These properties include the normalized volume（V/V0）, bulk modulus（B）, heat capacity（Cv）, thermal expansion coefficient（α）, and Debye temperature（■）. Finally, the electronic structures associated with the density of states（DOS） and Mulliken population are analyzed.

Preparation of microsized hematite powder from ferrous sulfate via microwave calcination1720-1726

摘要：The preparation of microsized hematite powder from ferrous sulfate using microwave calcination was investigated based on the TG/DTG curves. The decomposition of industrial ferrous sulfate under air atmosphere was divided into three stages, and a ferrous sulfate sample added with 15% Fe2O3 could strongly absorb microwave energy. Therefore, preparing hematite powder from ferrous sulfate using microwave calcination was feasible. Hematite was obtained under the following optimized conditions: calcination temperature, 850 °C; microwave power, 650 W; and sample amount, 40 g. The obtained hematite satisfied the first-grade quality requirements. The total ferrum value was more than 58%, and the total sulfur and phosphorus contents were less than 0.5% and 0.2%, respectively. X-ray powder diffraction and scanning electron microscopy were used to characterize the structure and morphology of microsized hematite powder. The particles were non-spherical in shape, and the average particle size distribution was 10.45 μm. This work provides new potential applications for waste ferrous sulfate.

A hybrid zeolitic imidazolate framework Co-IM-mIM membrane for gas separation1727-1735

摘要：A zeolitic imidazolate hybrid membrane（Co-IM-mIM） containing two imidazolate ligands deposited on a macroporous α-alumina support was prepared by pre-depositing and secondary growth technique. XRD, TGA and SEM characterizations demonstrate that a stable and thin, but dense and pure-phase Co-IM-mIM membrane can be obtained on the macroporous-alumina discs in Teflon-lined autoclave at 120 °C after pre-depositing by dip-coating at room temperature. No visible cracks, pinholes or other defects were observed on the membrane layer. The gas separation studies of Co-IM-mIM membrane were carried out at 25 °C and 1×105 Pa, showing ideal selectivity of 6.95, 5.25, 3.40 for H2/CO2, H2/N2 and H2/CH4, respectively, and a permeance of 17.37× 10-6 mol/（m2·s·Pa） for H2. The influence of temperature and trans-membrane pressure on hydrogen separation and permeation was also carried out. The gas permeation and selectivity demonstrate that this membrane may have potential applications for efficient H2 separation.

Inhibition mechanism between sodium（Na3AlF6） and sulfur on coke reactivity1736-1744

摘要：Inhibition mechanism between sodium（Na3AlF6） and sulfur on coke reactivity was investigated by simulating petroleum coke with low-impurity pitch coke and by impurity doping. The mechanism was discussed by scanning electron microscopy, energy-dispersive spectrometry, and X-ray powder diffraction. Results show that Na effectively inhibited S catalysis during carbon–air/CO2 reactions, and S inhibited the catalysis of Na during carbon– air reaction to a certain extent. A stable structure with a Na-to-S atomic ratio of 1.4 and a cyclic reaction system of “Na2SO3→ Na2S→ Na2CO3→ Na2SO3” were likely the keys to producing this mutual inhibition.

Sustainable synthesis of 5-hydroxymethylfurfural from waste cotton stalk catalyzed by solid superacid-SO42-/ZrO21745-1753

摘要：A sustainable process was explored for the preparation of 5-hydroxymethylfurfural（HMF） by catalytic degradation of the waste cotton stalk. Solid super-acid(SO42-/ZrO2) was used as an efficient catalyst for the degradation of cotton stalk. Both decomposition experiments and kinetic study were conducted for the exploration of degradation condition and kinetics mechanism. The optimized experimental conditions are reaction temperature 503 K, reaction time 75 min and dosage of catalyst 30%（mass fraction） based on the decomposition experiments, under which a maximum yield of 27.2% for HMF could be achieved. Kinetic study was then carried out in the presence of SO42-/ZrO2. The theoretical results indicate that the activation energies for reducing sugar and HMF with catalyst are 96.71 k J/mol, 84.21 kJ/mol in the presence of SO42-/ZrO2, and they are 105.96 k J/mol and 119.37 k J/mol in the absence of SO42-/ZrO2.

Effect of applied load on transition behavior of wear mechanism in Cu-15Ni-8Sn alloy under oil lubrication1754-1761

摘要：Tribological behavior of Cu-15Ni-8Sn（mass fraction, %） alloy against GCr15 ring under various loads was investigated on a ring-on-block tester in oil lubrication. The results showed that the wear rate increased slowly from 1.7×10-7 to 9.8× 10-7 mm3/mm under the load lower than 300 N, and then increased dramatically to the climax of 216×10-7 mm3/mm under the load over 300 N, which indicated the transition of wear mechanism with the increase of applied load. The wear mechanism mainly was plastic deformation and abrasive wear under the load less than 300 N. As the applied load was more than 300 N, the wear mechanism of Cu-15Ni-8Sn alloy primarily was delamination wear. Besides, the transition can also be confirmed from the different morphologies of worn surface, subsurface and wear debris. It is distinctly indicated that the appearance of flaky debris at the applied load over 300 N may be a critical point for the change of wear mechanism.

High-temperature acoustic properties of porous titanium fiber metal materials1762-1766

摘要：The high-temperature acoustic absorption performance of porous titanium fiber material was investigated in terms of sample thickness, porosity, temperature, air-cavity thickness and double-layer structure arrangement. The effects on absorption coefficient were systematically assessed. The results show that the sound absorption performance is improved by increasing the sample porosity and/or thickness, and/or increasing the air-cavity thickness. Meanwhile, increasing the temperature gives better acoustic absorption performance in the low frequency range but also lowers the performance in the high frequency range, while double-layer structure enables better acoustic absorption performance.

New method for calculating face gear tooth surface involving worm wheel installation errors1767-1778

摘要：The machining principle and realization method for the continuous generative grinding face gear by a worm wheel are introduced. Based on a five-axis linked CNC grinding machine, a new method is presented to deprive the equation of face gear error tooth surface by assuming the tool surface as the error surface, where actual tool installation position error is introduced into the equation of virtual shaper cutter. Surface equations and 3-D models for the face gear and the worm wheel involving four kinds of tool installation errors are established. When compared, the face gear tooth surface machined in VERICUT software for simulation based on this new method and the one obtained based on real process(grinding face gear by using a theoretical worm wheel with actual position errors) are found to be coincident, which proves the validity and feasibility of this new method. By using mesh planning for the rotating projection plane of the face gear work tooth surface, the deviation values of the tooth surface and the difference surface are acquired, and the influence of four kinds of errors on the face gear tooth surface is analyzed. Accordingly, this work provides a theoretical reference for assembly craft of worm wheel, improvement of face gear machining accuracy and modification of error tooth surface.

A novel hybrid estimation of distribution algorithm for solving hybrid flowshop scheduling problem with unrelated parallel machine1779-1788

摘要：The hybrid flow shop scheduling problem with unrelated parallel machine is a typical NP-hard combinatorial optimization problem, and it exists widely in chemical, manufacturing and pharmaceutical industry. In this work, a novel mathematic model for the hybrid flow shop scheduling problem with unrelated parallel machine(HFSPUPM) was proposed. Additionally, an effective hybrid estimation of distribution algorithm was proposed to solve the HFSPUPM, taking advantage of the features in the mathematic model. In the optimization algorithm, a new individual representation method was adopted. The(EDA) structure was used for global search while the teaching learning based optimization(TLBO) strategy was used for local search. Based on the structure of the HFSPUPM, this work presents a series of discrete operations. Simulation results show the effectiveness of the proposed hybrid algorithm compared with other algorithms.

THRFuzzy: Tangential holoentropy-enabled rough fuzzy classifier to classification of evolving data streams1789-1800

摘要：The rapid developments in the fields of telecommunication, sensor data, financial applications, analyzing of data streams, and so on, increase the rate of data arrival, among which the data mining technique is considered a vital process. The data analysis process consists of different tasks, among which the data stream classification approaches face more challenges than the other commonly used techniques. Even though the classification is a continuous process, it requires a design that can adapt the classification model so as to adjust the concept change or the boundary change between the classes. Hence, we design a novel fuzzy classifier known as THRFuzzy to classify new incoming data streams. Rough set theory along with tangential holoentropy function helps in the designing the dynamic classification model. The classification approach uses kernel fuzzy c-means(FCM) clustering for the generation of the rules and tangential holoentropy function to update the membership function. The performance of the proposed THRFuzzy method is verified using three datasets, namely skin segmentation, localization, and breast cancer datasets, and the evaluated metrics, accuracy and time, comparing its performance with HRFuzzy and adaptive k-NN classifiers. The experimental results conclude that THRFuzzy classifier shows better classification results providing a maximum accuracy consuming a minimal time than the existing classifiers.

Experimental and simulated studies on hydraulic buffering valve for ZF-4WG308 power-shift transmission1801-1807

摘要：The structure and working principle of a hydraulic buffering valve for a power-shift transmission ZF-4WG308 were studied comprehensively, and a model of the hydraulic buffering valve was developed with AMESim. A bench test was conducted on a buffering valve for transmissions(ZF-4WG308) and the test results agree well with the simulated results. Further more, the influences of the key parameters of the valve on the buffering performance were also studied in details.

Health risk of whole body vibration in mining trucks during various operational conditions1808-1816

摘要：Mining machineries are generally exposed to intensive vibrations in harsh mining environment. If vibrations are beyond the tolerable limit, the machine and its operator health will be under the risk. In this work, the vibration of a mining truck at different operational conditions are simulated and discussed. To achieve this aim, three haul roads with low, medium and poor qualities are considered based on the ISO standard. Accordingly, the vibration of a mining truck in different speeds, payload and distribution qualities of materials in the dump body are evaluated in each haul road quality using Trucksim software. The simulation results with statistical discussions indicate that the truck speed and the materials distribution quality have significant effects on the root mean square(RMS) of vertical vibrations. However, the effect of the payload is not considerable on the RMS. Moreover, the accumulation of materials on the rear side of the truck dump body is efficient on the vibrational health risk.

Improving cam profile design optimization based on classical splines and dynamic model1817-1825

摘要：Cam profiles play an important part in the performance of cam mechanisms. Syntheses of cam profile designs and dynamics of cam designs are studied at first. Then, a cam profile design optimization model based on the six order classical spline and single DOF(degree of freedom) dynamic model of single-dwell cam mechanisms is developed. And dynamic constraints such as jumps and vibrations of followers are considered. This optimization model, with many advantages such as universalities of applications, conveniences to operations and good performances in improving kinematic and dynamic properties of cam mechanisms, is good except for the discontinuity of jerks at the end knots of cam profiles which will cause vibrations of cam systems. However, the optimization is improved by combining the six order classical spline with general polynomial spline which is the so-called “trade-offs”. Finally, improved optimization is proven to have a better performance in designing cam profiles.

A novel SMC-PHD filter based on particle compensation1826-1836

摘要：As a typical implementation of the probability hypothesis density(PHD) filter, sequential Monte Carlo PHD(SMC-PHD) is widely employed in highly nonlinear systems. However, the particle impoverishment problem introduced by the resampling step, together with the high computational burden problem, may lead to performance degradation and restrain the use of SMC-PHD filter in practical applications. In this work, a novel SMC-PHD filter based on particle compensation is proposed to solve above problems. Firstly, according to a comprehensive analysis on the particle impoverishment problem, a new particle generating mechanism is developed to compensate the particles. Then, all the particles are integrated into the SMC-PHD filter framework. Simulation results demonstrate that, in comparison with the SMC-PHD filter, proposed PC-SMC-PHD filter is capable of overcoming the particle impoverishment problem, as well as improving the processing rate for a certain tracking accuracy in different scenarios.

Multi-objective planning model for simultaneous reconfiguration of power distribution network and allocation of renewable energy resources and capacitors with considering uncertainties1837-1849

摘要：This research develops a comprehensive method to solve a combinatorial problem consisting of distribution system reconfiguration, capacitor allocation, and renewable energy resources sizing and siting simultaneously and to improve power system’s accountability and system performance parameters. Due to finding solution which is closer to realistic characteristics, load forecasting, market price errors and the uncertainties related to the variable output power of wind based DG units are put in consideration. This work employs NSGA-II accompanied by the fuzzy set theory to solve the aforementioned multi-objective problem. The proposed scheme finally leads to a solution with a minimum voltage deviation, a maximum voltage stability, lower amount of pollutant and lower cost. The cost includes the installation costs of new equipment, reconfiguration costs, power loss cost, reliability cost, cost of energy purchased from power market, upgrade costs of lines and operation and maintenance costs of DGs. Therefore, the proposed methodology improves power quality, reliability and security in lower costs besides its preserve, with the operational indices of power distribution networks in acceptable level. To validate the proposed methodology’s usefulness, it was applied on the IEEE 33-bus distribution system then the outcomes were compared with initial configuration.

Optimal selection of annulus radius ratio to enhance heat transfer with minimum entropy generation in developing laminar forced convection of water-Al2O3 nanofluid flow1850-1865

摘要：Heat transfer and entropy generation of developing laminar forced convection flow of water-Al2O3 nanofluid in a concentric annulus with constant heat flux on the walls is investigated numerically. In order to determine entropy generation of fully developed flow, two approaches are employed and it is shown that only one of these methods can provide appropriate results for flow inside annuli. The effects of concentration of nanoparticles, Reynolds number and thermal boundaries on heat transfer enhancement and entropy generation of developing laminar flow inside annuli with different radius ratios and same cross sectional areas are studied. The results show that radius ratio is a very important decision parameter of an annular heat exchanger such that in each Re, there is an optimum radius ratio to maximize Nu and minimize entropy generation. Moreover, the effect of nanoparticles concentration on heat transfer enhancement and minimizing entropy generation is stronger at higher Reynolds.

Forming condition of transient saturated zone and its distribution in residual slope under rainfall conditions1866-1880

摘要：Rainfall, as one of the most significant factors triggering the residual soil slope failure, leads to not only the reduction of soil shear strength, but also the increase of soil weight and the decrease of matric suction as well. All these modifications in soil properties have important influence on the slope stability. The water infiltration and redistribution inside the slope are the preconditions of the slope stability under rainfall conditions. Based on the numerical simulation via finite element method, the water infiltration process under rainfall conditions was studied in the present work. The emphases are the formation, distribution and dissipation of transient saturated zone. As for the calculation parameters, the SWCC and the saturated permeability have been determined by pressure plate test and variable head test respectively. The entire process(formation, development, dissipation) of the transient saturated zone was studied in detail. The variations of volumetric water content, matric suction and hydraulic gradient inside the slope, and the eventually raise of groundwater table were characterized and discussed, too. The results show that the major cause of the formation of transient saturated zone is ascribed to the fact that the exudation velocity of rainwater on the wetting front is less than the infiltration velocity of rainfall; as a result, the water content of the soil increases. On the other hand, the formation and extension of transient saturated zone have a close relationship with rainfall intensity and duration. The results can help the geotechnical engineers for the deeper understanding of the failure of residual slope under rainfall condition. It is also suggested that the proper drainage system in the slope may be the cost-effective slope failure mitigation method.