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Catalytic steam reforming of biomass over Ni-based catalysts: Conversion from poplar leaves to hydrogen-rich syngas

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Journal of Natural Gas Chemistry 2011年第4期20卷 377-383页

作者： Lingyan cao Zhigang jia Shengfu Ji Jinyong Hu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China

A series of Ni/SBA-15 catalysts with Ni contents from 5 wt%–20 wt%and cao-12.5%Ni/SBA-15 catalysts with cao contents from 1.4 wt%– 9.8 wt%have been *** structure of the catalysts was characterized using X-ray diffraction（XRD）,N2 adsorption-desorption,transmission electron microscopy（TEM）and X-ray photoelectron spectroscopy（XPS）.The performance of catalytic steam reforming of the poplar leaves to the hydrogen-rich syngas was tested in a fixed-bed *** results indicate that the 7.0wt%cao-12.5wt%Ni/SBA-15 catalyst exhibits the best performance for the catalytic steam reforming of poplar leaves to hydrogen-rich *** ratio of H2：CO can reach ca 5：1 in the hydrogen-rich *** yield of H2 can reach 273.30 mL/g（poplar leaves）.In the cao-Ni/SBA-15 catalyst,Ni active component mainly fills the role of catalytic steam reforming of the poplar leaves,and cao active component mainly plays the role as water-gas shift and CO2 sorbent.

关键词： biomass steam reforming hydrogen-rich syngas Ni-basic catalyst cao

WAMS-based monitoring and control of Hopf bifurcations in multi-machine power systems

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第6期9卷 840-848页

作者： Shao-bu WANG Quan-yuan jiaNG Yi-jia cao School of Electrical Engineering Zhejiang University Hangzhou 310027 China

A method is proposed to monitor and control Hopf bifurcations in multi-machine power systems using the information from wide area measurement systems (WAMSs). The power method (PM) is adopted to compute the pair of conjugate eigenvalues with the algebraically largest real part and the corresponding eigenvectors of the Jacobian matrix of a power system. The distance between the current equilibrium point and the Hopf bifurcation set can be monitored dynamically by computing the pair of con- jugate eigenvalues. When the current equilibrium point is close to the Hopf bifurcation set, the approximate normal vector to the Hopf bifurcation set is computed and used as a direction to regulate control parameters to avoid a Hopf bifurcation in the power system described by differential algebraic equations (DAEs). The validity of the proposed method is demonstrated by regulating the reactive power loads in a 14-bus power system.

关键词： Wide area measurement system (WAMS) Hopf bifurcations Monitoring of bifurcations Control of bifurcations

Hydrolysis and Photolysis of Herbicide Clomazone in Aqueous Solutions and Natural Water Under Abiotic Conditions

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Journal of Integrative Agriculture 2013年第11期12卷 2074-2082页

作者： cao jia DIAO Xiao-ping HU Ji-ye School of Agriculture Hainan University School of Chemistry and Biological Engineering University of Science and Technology Beijing

The hydrolysis and photolysis of clomazone in aqueous solutions and natural water were assessed under natural and controlled conditions. Kinetics of hydrolysis and photolysis of clomazone were determined by HPLC-DAD. Photoproducts were identiifed by HPLC-MS. No noticeable hydrolysis occurred in aqueous buffer solutions （（25±2）°C, pH （4.5±0.1）, pH （7.4±0.1）, pH （9.0±0.1）;（50±2）°C, pH （4.5±0.1）, pH （7.4±0.1）） or in natural water up to 90 d. At pH （9.0±0.1） and （50±2）°C the half-life of clomazone was 50.2 d. Clomazone photodecomposition rate in aqueous solutions under UV radiation and natural sunlight followed ifrst-order kinetics. Degradation rates were faster under UV light （half-life of 51-59 min） compared to sunlight （half-life of 87-136 d）. Under UV light, four major photoproducts were detected and tentatively identiifed according to HPLC-MS spectral information such as 2-chlorobenzamide, N-hydroxy-（2-benzyl）-2-methylpropan-amide, 2-[2-phenol]-4,4-dimethyl-3-isoxazolidinone and 2-[（4,6-dihydroxyl-2-chlorine phenol）]-4,4-dimethyl-3-isoxazolidinone. These results suggested that clomazone photodegradation proceeds via several reaction pathways：1） dehalogenation;2） substitution of chlorine group by hydroxyl;3） cleavage of the side chain. Photosensitizers, such as H2O2 and ribolfavin, could enhance photolysis of clomazone in natural sunlight. In summary, we found that photoreaction is an important dissipation pathway of clomazone in natural water systems.

关键词： clomazone hydrolysis photolysis photoproducts abiotic

APPLICATION OF QUADRATIC AND CUBIC TURBULENCE MODELS ON CAVITATING FLOWS AROUND SUBMERGED OBJECTS

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Journal of Hydrodynamics 2012年第6期24卷 823-833页

作者： CHEN Ying LU Chuan-jing cao jia-yi CHEN Xin Department of Engineering Mechanics Shanghai Jiao Tong University Department of Engineering Mechanics and State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University

Quadratic and cubic Non-Linear Eddy-Viscosity Models （NLEVMs） at low Reynolds number （Re） correction were introduced into the present Computational Fluid Dynamics （CFD） framework, to provide better numerical treatment about the anisotropic turbulence stress in cavitating flows, which have large density ratio and large-scaled swirling flow structures. The applications of these NLEVMs were carried out through a self-developed cavitation code, coupled with a cavitation model based on the transport equation of liquid phase. These NLEVMs were firstly validated by the benchmark of disk supercavity, and found able to obtain more accurate capture of the hydrodynamic properties than the linear models. One of such models was further applied on the cavitation problem of submerged vehicles. Ultimately, the supercavitating flows around an especially designed underwater vehicle were predicted using the cubic k - e turbulence model, and its cavitation behaviors were studied.

关键词： cavitating flow Non-Linear Eddy-Viscosity Model (NLEVM) submerged object cavitation model

Forward and backward models for fault diagnosis based on parallel genetic algorithms

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第10期9卷 1420-1425页

作者： Yi LIU Ying LI Yi-jia cao Chuang-xin GUO School of Electrical Engineering Zhejiang University Hangzhou 310027 China

In this paper, a mathematical model consisting of forward and backward models is built on parallel genetic algorithms (PGAs) for fault diagnosis in a transmission power system. A new method to reduce the scale of fault sections is developed in the forward model and the message passing interface (MPI) approach is chosen to parallel the genetic algorithms by global sin-gle-population master-slave method (GPGAs). The proposed approach is applied to a sample system consisting of 28 sections, 84 protective relays and 40 circuit breakers. Simulation results show that the new model based on GPGAs can achieve very fast computation in online applications of large-scale power systems.

关键词： Forward and backward models Fault diagnosis Global single-population master-slave genetic algorithms (GPGAs) Parallel computation

Wall sheeting diagnosis in fluidized beds based on chaos analysis of acoustic emission signals

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第9期10卷 1341-1349页

作者： Yi-jia cao Jing-dai WANG Wei LIU Yong-rong YANG State Key Laboratory of Chemical Engineering Zhejiang University Hangzhou 310027 China Department of Chemical and Biochemical Engineering Zhejiang University Hangzhou 310027 China

A novel method, based on acoustic emission (AE) techniques, for detecting agglomeration in fluidized beds is presented. Particle size characteristics are determined based on the principle that AE signals with different frequency band energies are emitted when particles of different sizes impact an internal wall. By applying chaotic analysis to the AE signals, the malfunction coefficients are well defined. Agglomeration in the fluidized bed can then be detected by the sudden variation of malfunction coefficients. AE signals were investigated in a laboratory scale heated fluidized bed and an industrial polyethylene fluidized bed. Experimental data showed that the malfunction coefficients increased with the growth of agglomeration. The results indicated that agglomeration in fluidized beds can be predicted and diagnosed effectively and precisely using AE techniques based on chaotic analysis.

关键词： Acoustic emission (AE) Fluidized bed Malfunction coefficient Agglomeration Chaos

Optimal power flow calculation in AC/DC hybrid power system based on adaptive simplified human learning optimization algorithm

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Journal of Modern Power Systems and Clean Energy 2016年第4期4卷 690-701页

作者： jia cao Zheng YAN Xiaoyuan XU Guangyu HE Shaowei HUANG The Ministry of Education Key Laboratory of Control of Power Transmission and Conversion Department of Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Power Systems Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading effects of generators,carbon tax,and prohibited operating zones of generators,*** algorithm,involves random learning operator,individual learning operator,social learning operator and adaptive *** compare and analyze the computation performance of the ASHLO method,the proposed ASHLO method and other heuristic intelligent optimization methods are employed to solve OPF problem on the modified IEEE 30-bus and 118-bus AC/DC hybrid test *** results indicate that the ASHLO method has good convergent property and ***,the impacts of wind speeds and locations of HVDC transmission line integrated into the AC network on the OPF results are systematically analyzed.

关键词： Adaptive simplified human learning optimization algorithm Optimal power flow AC/DC hybrid power system Valve-point loading effects of generators Carbon tax Prohibited operating zones

RESEARCH ON THE BASE CAVITY OF A SUB-LAUNCHED PROJECTILE

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Journal of Hydrodynamics 2012年第2期24卷 244-249页

作者： cao jia-yi LU Chuan-jing CHEN Ying CHEN Xin LI Jie Department of Mechanics Shanghai Jiao Tong University Shanghai 200240 China MOE Key Laboratory of Hydrodynamics Shanghai Jiao Tong University Shanghai 200240 China

The finite volume method based on a multiphase model is adopted to solve the Reynolds-Averaged Navier-Stokes （RANS） equations,which takes into account the effects of fluid compressibility,viscosity,gravity,medium mixture and energy transfer of water and combustion *** program Fluent User Define Function （UDF） module combined with the dynamic mesh method is employed to simulate the coupling flow field of combustion gas,water field and trajectory of *** results show that the volume of gas cavity at the bottom of projectile and tail pressure will fluctuate after bottom of the projectile leaving the launch *** cause of the fluctuation is analyzed and its effects on the trajectory of projectile are *** numerical and experimental results agree well with each other.

关键词： sub-launched projectile gas cavity trajectory

Decreased Pollen Viability and Thicken Pollen Intine in Antisense Silenced Brassica campestris Mutant of BcMF19

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Journal of Integrative Agriculture 2014年第5期13卷 954-962页

作者： LIU Jin-long GAO Ming-hui LIU Ying cao jia-shu Laboratory of Cell and Molecular Biology Institute of Vegetable Science Zhejiang University

Brassica campestris male fertility 19 （BcMF19; GenBank accession number GQ902048.1）, a gene that is specially expressed in tapetum cells and microspores during anther development in B. campestris ssp. chinensis, which is learned from the previous in situ hybridization study. In the present study, we constructed antisense-silenced plants of BcMF19 using B. campestris ssp. chinensis to validate this prediction. The morphology of the pistils, long anthers, and short anthers was significantly affected in 35sbcmf19 compared with the control samples. 4＇-6-Diamidino-2-phenylindole staining revealed that two generative nuclei and one large vegetative nucleus were not affected in the mutant compared with control. Statistical analysis of Alexander＇s staining results showed that 96% of the control pollen grains had vitality, whereas only 86% of the mutant pollen grains did. Under scanning electron microscopy, the mutant demonstrated numerous abnormal pollen grains and resembled dried persimmon. The frequency of normal pollen grains was approximately 18%. Under transmission electron microscopy, the pollen intine during the binucleate and mature pollen stages in 35sbcmf19 exhibited abnormal thickening, especially at the germinal furrows, compared with control. In vitro pollen germination test showed that the tips of the mutant pollen tubes transformed into globular alveoli and stopped growing compared with control. On the other hand, in vivo pollen germination test suggested that BcMF19 affected the pollen tube extension in the pistil. These findings indicate that BcMF19 is essential to the pollen development and pollen tube extension orB. campestris ssp. chinensis.

关键词： Brassica rapa ssp. chinensis PGIP pollen polygalacturonase-inhibiting protein tapetum pollen germination