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Journal of Environmental Sciences 2013年第7期25卷 1492-1499页

作者： Dina Tan Honghu Zeng Jie Liu Xiaozhang Yu Yanpeng Liang Lanjing Lu College of Environmental Science and Engineering Guilin University of Technology guangxi Institute of Building Research & Design guangxi polytechnic of construction

The kinetics of thedegradation of trace nitrobenzene （NB） by a granular activated carbon （GAC） enhanced microwave （MW）/hydrogen peroxide （H202 ） systemwas studied. Effects of pH, NB initial concentration and tert-butyl alcohol on the removal efficiencywere examined. Itwas found that the reaction rate fitswell to first-order reaction kinetics in the MW/GAC/H202 process. Moreover, GAC greatly enhanced thedegradation rate of NB inwater. Under a given condition （MW power300 W, H202dosage 10 mg/L, pH 6.85 and temperature （60 ± 5）°C）, thedegradation rate of NBwas 0.05214 min 1when4 g/L GACwas added. In general, alkaline pHwas better for NBdegradation; however, the optimum pHwas 8.0 in the tested pH value range of4.0-12.0. At H202dosage of 10 mg/L and GACdosage of4 g/L, the removal of NBwasdecreasedwith increasing initial concentrations of NB, indicating that a low initial concentrationwas beneficial for thedegradation of NB. These results indicated that the MW/GAC/H202 processwas effective for trace NBdegradation inwater. Gas chromatography-mass spectrometry analysis indicated that a hydroxyl radical addition reaction anddehydrogenation reaction enhanced NBdegradation.

关键词： microwave granular activated carbon hydrogen peroxide nitrobenzene hydroxyl radicals

Study on the Quantitative Relationship between the Structure and Toxicity of Organophosphorus Pesticide

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Chinese Journal of Structural Chemistry 2015年第10期34卷 1473-1478页

作者：莫凌云覃如琼覃礼堂曾鸿鹄梁延鹏 Department of Environmental Science and Engineering Guilin University of Technology guangxi Key Laboratory of Environmental Pollution Control Theory and Technology guangxi polytechnic of construction

The molecular electronegativity distance vector（MEDV） was applied to characterize the molecular structures of 30 organophosphorous compounds. Optimum MEDV descriptors were selected by using the variable selection and modeling method based on the prediction（VSMP） technique. The quantitative structure-toxicity relationship（QSTR） model was built for acute toxicity（96h pLC50） of organophosphorous compounds to steelhead. The developed QSTR model with strictly internal and external validations presents relatively high correlation coefficient（R2） of 0.9518, leave-one-out（LOO） cross-validated correlation coefficient（Q2LOO） of 0.9355, and leave-many-out（LMO） cross-validated correlation coefficient（Q2LMO） of 0.9290. The robustness of the model was confirmed by the y-randomization test（R2yrand = 0.0772 and Q2 yrand = –0.5313） and bootstrapping（R2bstr = 0.9502 and Q2 bstr = 0.9177） method. The result of external validation, Q2F1 = 0.9336, Q2F2 = 0.9336, Q2F3 = 0.9447, r2 m = 0.8120, and CCC = 0.9602, shows that the QSTR model has a high predictive ability.

关键词： molecular electronegativity distance vector(MEDV) QSTR organophosphorus pLC50

Estimation of the complex frequency of a harmonic signal based on a linear least squares method

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Geodesy and Geodynamics 2015年第3期6卷 220-225页

作者： He Meilin Xiu Yanxia guangxi polytechnic of construction Institute of Surveying and Mapping Wuhan

In this study, we propose a simple linear least squares estimation method(LLS) based on a Fourier transform to estimate the complex frequency of a harmonic signal. We first use a synthetically-generated noisy time series to validate the accuracy and effectiveness of LLS by comparing it with the commonly used linear autoregressive method(AR). For an input frequency of 0.5 m Hz, the calculated deviations from the theoretical value were 0.004‰and 0.008‰ for the LLS and AR methods respectively; and for an input 5 10 6attenuation,the calculated deviations for the LLS and AR methods were 2.4% and 1.6%. Though the theory of the AR method is more complex than that of LLS, the results show LLS is a useful alternative method. Finally, we use LLS to estimate the complex frequencies of the five singlets of the0S2 mode of the Earth’s free oscillation. Not only are the results consistent with previous studies, the method has high estimation precisions, which may prove helpful in determining constraints on the Earth’s interior structures.

关键词： Harmonic signal Complex frequency Least squares es

Degradation of trace nitrobenzene in water by microwave-enhanced H2O2-based process

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Frontiers of Environmental Science & Engineering 2012年第4期6卷 477-483页

作者： Honghu ZENG Lanjing LU Meina LIANG Jie LIU Yanghong LI College of Environmental Science and Engineering Guilin University of TechnologyGuilin 541004China guangxi polytechnic of construction Nanning 530003China

To evaluate possible use of microwave- enhanced H2O2-based （MW/H2O2） process to degrade trace nitrobenzene （NB） in water, a series of batch experiments were conducted. The results showed that 2450MHz microwave irradiation significantly enhanced oxidative decomposition of nitrobenzene （NB） in a H2O2 system. About 90% NB was degraded by the MW/H2O2 process in 30 min. Moreover, the MW/H2O2 process could enhanced the oxidative degradation of NB even at relatively low temperature （50℃）. When the initial concentration of NB was 300gg/L, the optimum ratio of H2O2 to NB and MW power were 70 and 300W respectively. The presence of humic acid significantly increased H2O2 dosage. The ultraviolet absorbance at 254 nm （UV254） indicated degradation of NB was stepwise and some intermediates were produced. The gas chromatography-mass spectrometric （GC-MS） analysis showed that main intermediates were nitrophenolic and carbonyl compounds.

关键词： microwave hydrogen peroxide nitrobenzene humic acid

Method of non-stationary random vibration reliability of hydro-turbine generator unit

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Acta Mechanica Sinica 2024年第9期40卷 98-115页

作者： Zhaojun Li Fuxiu Liu Ganwei Cai Jiang Ding Jiaquan Chen College of Civil Engineering and Architecture Guangxi UniversityNanning 530004China College of Mechanical Engineering Guangxi UniversityNanning 530004China School of construction Machinery Hunan Sany Polytechnic CollegeChangsha 410129China

The hydraulic excitation acting on a hydro-turbine generator unit exhibits obvious non-stationary *** order to account for these characteristics,this study focuses on the non-stationary random vibration reliability of the hydro-turbine generator ***,the non-stationary characteristics of the hydraulic excitation are analyzed,and a mathematical ex-pression is constructed using the virtual excitation ***,a dynamic model of the unit is established to demonstrate the non-stationary random vibration characteristics under hydraulic ***,an active learning non-stationary vibration reliability analysis method AK-MCS-T-H is proposed combining the Kriging model,the Monte Carlo simulation(MCS)method,and the information entropy learning function *** method reveals the influence of the non-stationary hydraulic excitation on the random vibration reliability of the hydro-turbine generator ***,an example is presented to analyze the random vibration *** study shows that the AK-MCS-T-H proposed in this paper can solve the problem of non-stationary random vibration reliability of the Francis hydro-turbine generator unit more effectively.

关键词： Hydro-turbine generator unit Hydraulic excitation Non-stationarity Vibration reliability Active learning

The Meso-inhomogeneous Deformation of Pure Copper under Tension-Compression Cyclic Strain Loading

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Acta Mechanica Solida Sinica 2020年第3期33卷 403-417页

作者： Lili Jin Shenghuan Qin Bin Zeng Yingjun Gao Keshi Zhang guangxi Key Lab of Disaster Prevention and Engineering Safety Key Lab of Disaster Prevention and Structural SafetyCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China Urban construction and Transportation Engineering Department Guangxi Polytechnic of ConstructionNanning 530007China School of Physical Science and Technology Guangxi UniversityNanning 530004 China College of Civil and Architectural Engineering Nanning UniversityNanning 530200China

The investigation based on experiments and crystal plasticity simulation is carried out to undertake research on mesodeformation inhomogeneity of metals under cyclic loading at grain *** tension-compression cycle tests are performed on pure copper specimens to observe the inhomogeneous distribution of slip deformation and its evolution with cycle *** hardening process and stable hysteretic behavior of pure copper under cyclic loading are simulated by applying a crystal plasticity constitutive model including nonlinear kinematic hardening associated with the polycrystalline representative volume element(RVE)constructed by Voronoi *** deformation processes of materials under six different strain amplitudes are simulated by 1600 cycles,*** discuss the variation law of the inhomogeneous meso-deformation distribution of material with the increase in cycle number,and research the rationality of characterizing the inhomogeneous deformation distribution and variation with the statistical standard deviation of the micro-longitudinal strain or the statistical average of the first principal strain based on the statistical analysis of the inhomogeneous deformation of the polycrystalline RVE model during the cycling *** is found that these two parameters are related to and approximately inversely proportional to the length of measuring gauge.

关键词： Strain cycle Deformation inhomogeneity Polycrystalline representative volume element Measuring gauge Crystal plasticity

YIELD SURFACES AND PLASTIC FLOW OF 45 STEEL UNDER TENSION-TORSION LOADING PATHS

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Acta Mechanica Solida Sinica 2012年第4期25卷 348-360页

作者： Guijuan Hu Keshi Zhang Shihong Huang Jiann-Wen Woody Ju Key Laboratory of Disaster Prevention and Structural Safety Guangxi UniversityNanning 530004China guangxi polytechnic of construction Nanning 530004China Department of Civil and Environmental Engineering University of CaliforniaLos AngelesCA 90095-1593USA

An experimental analysis on the subsequent yield-surfaces evolution using multiple specimens is presented for a 45 steel after a prescribed pre-strain loading in three different directions respectively, and the yielding is defined by a designated offsetting strain. The size of the subsequent yield surface is found smaller than the initial yield surface; the negative cross effects are observed in the normal loading direction, its shape is not a Mises circle but has a rather blunt nose in loading direction and flat in the opposite. These results strongly depend on the loading path and the prescribed offset plastic strain. The plastic flow direction to the subsequent yield surface is investigated, and it is found that the plastic flow direction deviates from the normal flow rule. The deviation differs from preloading case to preloading case. And the plastic flow direction would have a larger deviation from the normal of the yield surface, if the subsequent yield was defined by a smaller offset strain. Furthermore, the experiments are simulated using the Chaboche model, and the results show that it can rationally predict yield-surface only when yield is defined by a fairly large offset strain.

关键词： subsequent yield surface plastic flow direction multiple specimen methods offsetstrain

Research on Enterprise Mobile Office Platform based on Cloud Computing

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International Journal of Technology Management 2015年第2期 37-40页

作者： Jianfeng WEN guangxi polytechnic of construction NarmingGuangxi530003 China

This paper systematically analyzes the structure and function of mobile office system in cloud platform, puts forward the method how to blend the advantages of cloud computing to organically integrate mobile office scene. Firstly, this paper introduces the key technology of mobile OA platform based on cloud computing; secondly, this paper proposes the ideas of cloud computing middleware combination with original system, and on this basis, forming a mobile office architecture model based on cloud computing, gives the mobile office platform architecture scheme, combined with the actual development problems in some model specifications and solutions to build mobile office system based on cloud computing..

关键词： Communication Cloud-computing Mobile Office Cloud middleware Mobile technology

Visualisation study on water management of cathode dead-ended PEMFC under pressure-swing operation

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Progress in Natural Science:Materials International 2024年第4期34卷 814-823页

作者： Houchang Pei Zhangda Liu Liangbo Sun Beihai Wang Jibin Chen Lu Xing School of Mechanical Engineering Wuhan Polytechnic University Mechanical and construction Engineering Northumbria University

Dead-ended proton exchange membrane fuel cells(PEMFC) using pure hydrogen oxygen can improve fuel efficiency and simplify fuel cell systems have been wildly used for a closed space. But the dead-ended operation of the PEMFC will cause difficulties in water management, especially in the cathode side, resulting in deteriorating of fuel cell stability. For this reason, gravity assisted drainage method, static drainage method are designed to migrate the water out of the cell. However, even with these methods, the reliability of the water removing from the cell remains questionable. Therefore, this paper introduces a novel water removal method to solve these problems and visualisation techniques were used to a more comprehensive knowledge of water transport mechanisms in dead-ended PEMFCs. A pressure-swing operation is realized by controlling the inlet of PEMFC solenoid valve to remove water and recycle oxygen during purging. The dynamic response characteristics of this system under different current densities, pressure differences, cell temperature and purging intervals are experimentally investigated in detail. It found that the water removal rate of the cathode flow channel of dead-ended PEMFC was as high as 99.25 %, and the fuel utilisation of the cell was close to 100 % in this water management mode.

关键词： Visualisation Pressure-swing Dead-ended PEMFC Water management

Effect of rock composition microstructure and pore characteristics on its rock mechanics properties

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International Journal of Mining Science and Technology 2018年第2期28卷 303-308页

作者： Li Huamin Li Huigui Wang Kailin Liu Chuang School of Energy Science and Engineering Henan Polytechnic University Opening Project of Key Laboratory of Deep Mine construction Henan Polytechnic University

This paper is to study the influence of composition, microstructure and pore characteristics on the rock mechanical properties. Five kinds of sandstone compositions were analyzed by using X-ray diffraction instrument. And the microstructure was observed by using scanning electron microscope. Then the pore distribution characteristic was investigated by using the low field nuclear magnetic resonance equipment. Finally, the uniaxial compression test was carried out to investigate the mechanical characteristics by using RMT150C mechanics experimental system and the uniaxial compressive strength, Poisson's ratio and elastic modulus were obtained. Compared to the analysis of the composition, structure and pore distribution and mechanical properties of the five kinds of sandstones, the relationship among composition,structure, pore distribution and mechanical properties was obtained. The results show that the composition, microstructure, pore distribution and mechanical properties of sandstone are closely *** the decrease of feldspar and quartz particles, the compressive strength and elastic modulus increase, while the porosity decreases.

关键词： Mechanical characteristics Pore characteristics Microstructure Composition Scanning electron microscope