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Development of an ε-type actuator for enhancing high-speed electro-pneumatic ejector valve performance

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Journal of zhejiang University-Science A(Applied Physics & Engineering) 2008年第11期9卷 1552-1559页

作者： Zhong XIANG Hao LIU Guo-Liang TAO Jun MAN Wei ZHONG State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

A novel ε-type solenoid actuator is proposed to improve the dynamic response of electro-pneumatic ejector valves by reducing moving mass weight. A finite element analysis (FEA) model has been developed to describe the static and dynamic operations of the valves. Compared with a conventional E-type actuator, the proposed ε-type actuator reduced the moving mass weight by almost 65% without significant loss of solenoid force, and reduced the response time (RT) typically by 20%. Prototype valves were designed and fabricated based on the proposed ε-type actuator model. An experimental setup was also established to investigate the dynamic characteristics of valves. The experimental results of the dynamics of valves agreed well with simulations, indicating the validity of the FEA model.

关键词： ε-type actuator High-speed electro-pneumatic ejector valve Finite element method Dynamic simulation and experiment

Moisture sorption characteristics of freeze-dried human platelets

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Journal of zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第3期12卷 210-218页

作者： Meng-jie XU Guang-ming CHEN Ju-li FAN Jin-hui LIU Xian-guo XU Shao-zhi ZHANG Institute of Refrigeration and Cryogenics Zhejiang University Hangzhou 310027 China College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Key Laboratory of Blood Safety Research Ministry of Health Blood Center of Zhejiang Province Hangzhou 310006 China

Freeze-drying is a promising method for a long-term storage of human *** moisture sorption characteristics of freeze-dried human platelets(FDHPs) were studied in this *** moisture sorption isotherms of FDHPs and freeze-dried lyophilization buffer(FDLB) were measured at 4,25,and 37°*** experimental data were fitted to Brunauer-Emmett-Teller(BET) and Guggenheim-Anderson-de Boer(GAB) *** were no sig-nificant statistical differences(P>0.05) between the sorption characteristics of FDHPs and FDLB at 4 and 25°C,while FDHPs absorbed more water at 37°*** net isosteric heat of sorption was *** heat for FDHPs showed an abnormal negative value at low moisture contents when 25 and 37°C data were *** sorption experiments were carried out at 25°C with environmental water activity controlled at 0.75,0.85,and *** moisture diffusion coefficient was fitted to be 8.24×10 -12 m 2 /s when experimental data at initial time were *** results would be helpful in choosing prehydration and storage condition for FDHPs.

关键词： Human platelets Freeze-drying Sorption Moisture

Corrosion performance of zinc coated steel in seawater environment

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Chinese Journal of Oceanology and Limnology 2017年第2期35卷 423-430页

作者：刘栓赵霞赵海超孙虎元陈建敏 Key Laboratory of Marine Materials and Related Technologies Zhejiang Key Laboratory of Marine Materials and Protective TechnologiesNingbo Institute of Materials Technologies and EngineeringChinese Academy of Sciences Key Laboratory of Marine Environmental Corrosion and Bio-Fouling Institute of OceanologyChinese Academy of Sciences

Considering the continuous exploitation of marine resources, it is very important to study the anticorrosion performance and durability of zinc coated streel （ZCS） because its increasing use as reinforcements in seawater. Tafel polarization curves and linear polarization curves combined with electrochemical impedance spectroscopy （EIS） were employed to evaluate the corrosion performance of ZCS at Qingdao test station during long-term immersion in seawater. The results indicated that the corrosion rate of the ZCS increased obviously with immersion time in seawater. The corrosion products that formed on the zinc coated steel were loose and porous, and were mainly composed of Zn5（OH）8C12, Zn5（OH）6（CO3）2, and ZnO. Pitting corrosion occurred on the steel surface in neutral seawater, and the rate of ZCS corrosion decreased with increasing pH.

关键词： zinc coated steel seawater corrosion behavior pitting

Online process monitoring for complex systems with dynamic weighted principal component analysis

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Chinese Journal of Chemical Engineering 2016年第6期24卷 775-786页

作者： Zhengshun Fei Kangling Liu School of Automation and Electrical Engineering Zhejiang University of Science and Technology Hangzhou 310023 China State Key Lab of Industrial Control Technology Institute of Industrial Control Technology College of Control Science and Engineering Zhejiang University Hangzhou 310027 China

Conventional multivariate statistical methods for process monitoring may not be suitable for dynamic processes since they usually rely on assumptions such as time invariance or uncorrelation. We are therefore motivated to propose a new monitoring method by compensating the principal component analysis with a weight *** proposed monitor consists of two tiers. The first tier uses the principal component analysis method to extract cross-correlation structure among process data, expressed by independent components. The second tier estimates auto-correlation structure among the extracted components as auto-regressive models. It is therefore named a dynamic weighted principal component analysis with hybrid correlation structure. The essential of the proposed method is to incorporate a weight approach into principal component analysis to construct two new subspaces, namely the important component subspace and the residual subspace, and two new statistics are defined to monitor them respectively. Through computing the weight values upon a new observation, the proposed method increases the weights along directions of components that have large estimation errors while reduces the influences of other directions. The rationale behind comes from the observations that the fault information is associated with online estimation errors of auto-regressive models. The proposed monitoring method is exemplified by the Tennessee Eastman process. The monitoring results show that the proposed method outperforms conventional principal component analysis, dynamic principal component analysis and dynamic latent variable.

关键词： Principal component analysisWeightOnline process monitoringDynamic

Simulation of the relationship between porosity and tortuosity in porous media with cubic particles

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Chinese Physics B 2012年第10期21卷 1-8页

作者：唐晓武孙祖峰程冠初 MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Department of Civil EngineeringZhejiang University

Tortuosity is an important parameter used in areas such as vascular medicine,neurobiology,and the field of soil permeability and diffusion to express the mass transport in porous *** is a function of the porosity and the shape and distribution of *** this paper,the tortuosity of cubic particles is *** the assumption that the porous medium is homogeneous,the problem is converted to the micro-level over a unit cell,and geometry models of flow paths are *** three-dimensional（3D） cells,the flow paths are too complicated to ***,the 3D models are converted to two-dimensional（2D） models to simplify the calculation *** is noticed that the path in the 2D model is shorter than that in the 3D *** a result,triangular particles and the interaction are also taken into consideration to account for the longer distance *** have proposed quadrate particle and interaction（QI） and quadrate and triangular particle（QT） models with cubic *** models have shown good agreement with the experimental *** is also found that they can predict the toruosities of some kinds of porous media,like freshwater sediment and Negev chalk.

关键词： tortuosity porosity porous media cubic particles

Visual outcome and optical quality after bilateral implantation of aspheric diffractive multifocal, aspheric monofocal and spherical monofocal intraocular lenses: a prospective comparison

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International Journal of Ophthalmology(English edition) 2013年第3期6卷 300-306页

作者： Pan-Pan Ye Xia Li Ke Yao Eye Center the Second Affiliated Hospital College of Medicine Zhejiang University

·AIM: To evaluate the visual function after bilateral implantation of aspheric diffractive multifocal Tecnis ZMA00, aspheric monofocal ZA9003 versus spherical monofocal Akreos Adapt intraocular lenses (IOLs). ·METHODS: Tecnis ZMA00, Tecnis ZA9003 or Akreos Adapt IOLs were bilaterally implanted in 180 eyes from 90 patients. The following parameters were assessed 3 months postoperatively: monocular and binocular uncorrected visual acuity (UCVA) and distance-corrected visual acuity (DCVA) for distance, intermediate and near, spherical aberration (SA), contrast and glare sensitivity, near point refractive power, uncorrected and best corrected near stereoscopic acuity (NSA). Patient satisfaction was assessed by a questionnaire. ·RESULTS:Threemonthspostoperatively,themonocular and binocular UCVA and DCVA at near of Tecnis ZMA00 were significantly better than other two groups. The mean SA for 5.0mm optical zone in Tecnis ZMA00 and Tecnis ZA9003 was significantly lower than that in Akreos Adapt. Mean contrast sensitivity and glare sensitivity were better for Tecnis ZA9003 group than for other two groups. Patients with Tecnis ZMA00 had higher monocular and binocular near point refractive power and uncorrected NSA than monofocal groups. The patients in Tecnis ZMA00 had higher mean values for halo compared with other two groups. ·CONCLUSION: Tecnis ZMA00 provided better near VA and uncorrected NSA and higher near point refractive power than monofocal IOLs and patients were spectacle independent. The IOLs with Tecnis aspheric design improved contrast and glare sensitivity. Patients with Tecnis ZMA00 reported more disturbances on visual phenomena of halo. ·

关键词： intraocular lens aberration visual acuity multifocal

Assessment of the TFM in predicting the onset of turbulent fluidization

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Chinese Journal of Chemical Engineering 2019年第5期27卷 979-992页

作者： Musango Lungu Haotong Wang Jingdai Wang Ronald Ngulube Yongrong Yang Fengqiu Chen John Siame State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 31002乙 China Chemical Engineering Department School of Mines and Mineral SciencesCopperbelt University10101 KitweZambia

Accurate prediction of the onset of turbulent fluidization still remains elusive owing to the dependence of the transition velocity on several factors including measurement methods and interpretation of results. In this work, numerical simulations using the two fluid model (TFM) are performed in an attempt to predict the regime change reported by Gopalan etal.(2016) in a small scale pseudo-2D gas-solid fluidized bed containing Geldart D particles. Various time and frequency domain analyses were applied on predicted absolute and differential pressure time series data to reveal the bed dynamics. Numerical predictions of the transition velocity, Uc are in reasonably good agreement with experimental results from the small scale challenge problem. The literature correlations completely fail to predict the transition velocity for the system considered in this work. This work thus provides a different approach for validating the CFD model against experimental measurements.

关键词： CFD Fluidization Regime identification Slugging Turbulent Wavelet analysis

Electron–acoustic phonon interaction and mobility in stressed rectangular silicon nanowires

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Chinese Physics B 2015年第1期24卷 411-417页

作者：朱林利 Department of Engineering Mechanics School of Aeronautics and Astronautics Zhejiang University

We investigate the effects of pre-stress and surface tension on the electron–acoustic phonon scattering rate and the mobility of rectangular silicon nanowires. With the elastic theory and the interaction Hamiltonian for the deformation potential, which considers both the surface energy and the acoustoelastic effects, the phonon dispersion relation for a stressed nanowire under spatial confinement is derived. The subsequent analysis indicates that both surface tension and pre-stress can dramatically change the electron–acoustic phonon interaction. Under a negative（positive） surface tension and a tensile（compressive） pre-stress, the electron mobility is reduced（enhanced） due to the decrease（increase） of the phonon energy as well as the deformation-potential scattering rate. This study suggests an alternative approach based on the strain engineering to tune the speed and the drive current of low-dimensional electronic devices.

关键词： phonon properties elastic model electron–acoustic phonon interaction carrier mobility

Cu–Mn–Ce ternary mixed-oxide catalysts for catalytic combustion of toluene

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Journal of Environmental Sciences 2015年第6期27卷 102-107页

作者： Hanfeng Lu Xianxian Kong Haifeng Huang Ying Zhou Yinfei Chen Institute of Catalytic Reaction Engineering College of Chemical Engineering Zhejiang University of Technology College of Biological and Environmental Engineering Zhejiang University of Technology

Cu-Mn, Cu-Mn-Ce, and Cu-Ce mixed-oxide catalysts were prepared by a citric acid sol-gel method and then characterized by XRD, BET, H_2-TPR and XPS analyses. Their catalytic properties were investigated in the toluene combustion reaction. Results showed that the Cu-Mn-Ce ternary mixed-oxide catalyst with 1：2：4 mole ratios had the highest catalytic activity, and 99% toluene conversion was achieved at temperatures below 220°C. In the Cu-Mn-Ce catalyst, a portion of Cu and Mn species entered into the Ce O2 fluorite lattice, which led to the formation of a ceria-based solid solution. Excess Cu and Mn oxides existed on the surface of the ceria-based solid solution. The coexistence of Cu-Mn mixed oxides and the ceria-based solid solution resulted in a better synergetic interaction than the Cu-Mn and Cu-Ce catalysts, which promoted catalyst reducibility, increased oxygen mobility, and enhanced the formation of abundant active oxygen species.

关键词： Cu-Mn-Ce mixed oxide Toluene Catalytic combustion Volatile organic compounds(VOCs)