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Chemical Research in Chinese Universities 2004年第4期20卷 411-416页

作者： lai x. MA C. K. J. Robert M. C. Miller Institute of Particle Science and Engineering Department of Chemical Engineering University of LeedsInstitute of Particle Science and Engineering Department of Chemical Engineering University of LeedsInstitute of Particle Science and Engineering Department of Chemical Engineering University of LeedsCCLRC Daresbury Laboratory Daresbury Leeds LS2 9JT UKLeeds LS2 9JT UKLeeds LS2 9JT UKWarrington Cheshire WA4 4AD UK

A novel crystal characterization instrument has been built up in which a combination of x.ray multiple diffraction and x.ray topography is applied to enabling the cross-correlation between micro-crystallographic symmetry and its spatial dependence in relation to lattice defects. This facility is used to ex.mine, in a self-consistent manner, growth sector-dependant changes to both the crystallographic structure and the lattice defects associated with the action of habit-modifying additives in a number of representative crystal growth systems. In addition, the new instrument can be used to probe micro-crystallographic aspects(such as distortion to crystal symmetry) and relate these in a spatially resolved manner to the crystal defect structure in crystals doped with known habit modifiers.

关键词： x.ray diffraction x.ray multiple diffraction x.ray topography Habit modification Crystal growth Growth defects

New Distributed Positioning Algorithm Based on Centroid of Circular Belt for Wireless Sensor Networks

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International Journal of Automation and computing 2007年第3期4卷 315-324页

作者： x.-Zhi lai Simon x. Yang Gui-x.u Zeng Jin-Hua She Min Wu School of Information Science ＆ Engineering Central South UniversityChangsha 410083PRC Advanced Robotics and Intelligent Systems Laboratory School of EngineeringUniversity of GuelphGuelphOntario NIG 2W1Canada School of Bionics Tokyo University of Technology1404-1 KatakuraHachiojiTokyo 192-0982Japan

This paper presents a new distributed positioning algorithm for unknown nodes in a wireless sensor network. The algorithm is based ex.lusively on connectivity. First, assuming that the positions of the anchor nodes are already known, a circular belt containing an unknown node is obtained using information about the anchor nodes that are in radio range of the unknown node, based on the geometric relationships and communication constraints among the unknown node and the anchor nodes. Then, the centroid of the circular belt is taken to be the estimated position of the unknown node. Since the algorithm is very simple and since the only communication needed is between the anchor nodes and the unknown node, the communication and computational loads are very small. Furthermore, the algorithm is robust because neither the failure of old unknown nodes nor the addition of new unknown nodes influences the positioning of unknown nodes to be located. A theoretical analysis and simulation results show that the algorithm does not produce any cumulative error and is insensitive to range error, and that a change in the number of sensor nodes does not affect the communication or computational load. These features make this algorithm suitable for all sizes of low-power wireless sensor networks.

关键词： Positioning wireless sensor networks circular belt algorithm performance.

Numerical Study of an Annular Gas Turbine Combustor with Dump Diffuser

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Journal of Thermal Science 1999年第1期8卷 59-64页

作者： J.x.Zhao Y.B.lai DepartmentofPowerEngineering NanjingUniversityofAeronauticsandAstronautics210016NanjingChina Depar

A general numerical method is presented for calculating steady three-dimensional and two-phase turbulent reactive flows with a nonstaggered body-fitted coordinate system in an annular gas turbine combustor with the dump diffuser. The modified two-equation model and the EDC turbulent combustion model are used for the gas phase. The liquid phase equations are solved in a Lagrangian frame of reference by PSIC algorithm. The effect of different velocity profiles at the entry of the prediffuser on combustor flow characteristics is calculated.

关键词： numerical simulation annular combustor dump diffuser 3D body-fitted coordinate two phase combustion.

Nano-phase transformation of composite precipitates in multicomponent Al-Mg-Si(-Sc)alloys

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Journal of Materials Science & Technology 2022年第15期110卷 216-226页

作者： S.B.Wang C.F.Pan B.Wei x.Zheng Y.x.lai J.H.Chen Key Laboratory of LCR Materials and Devices of Yunnan Province National Center for International Research on Photoelectric and Energy MaterialsSchool of Materials and EnergyYunnan UniversityKunming 650091China Collaborative Innovation Center of Renewable Energy Materials and Department of Physics Guangxi UniversityNanning 530004China Center for High-Resolution Electron Microscopy College of Materials Science and EngineeringHunan UniversityChangsha 410082China

Sc-addition can significantly enhance the performance of the micro-alloyed Al-Mg-Si-Sc ***,the mechanisms by which the Sc element modifies the microstructure of the alloys are still unknown in many ***,using atomic-scale transmission electron microscopy and atomic-resolution spectroscopy,we have revealed the microstructural differences between two age-hardened Al-0.5Mg-0.4Si(wt.%)alloys with and without *** first significant effect of Sc-addition on the precipitation microstructure of the Al-Mg-Si-Sc alloy is that Sc-atoms may distribute at theβ"-precipitate/Al-matrix.interface and therefore accelerate aging kinetics at the initial stage of *** second significant effect of Sc-addition is that in the transition from theβ"-hardened peak-age stage to theβ′-hardened late stage,Sc-atoms can greatly improve the stability of transitionalβ"/B'/β′composite precipitates by entering the B'-substructures and/or locating at the precipitate/Al *** such Sc-atoms effectively suppressβ"toβ'transformation and cross-sectional coarsening of bothβ"and composite precipitates,leading to much finer precipitate needles with smaller diameter but much larger length,as compared with those precipitate needles formed in the alloy without ***,the alloy with Sc-addition ex.ibits a much better thermal stability than that without Sc.

关键词： Al alloy Strengthening mechanism Phase transition Transmission electron microscopy

Investigation on 3Dt wake flow structures of swimming bionic fish

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Acta Mechanica Sinica 2012年第5期28卷 1494-1508页

作者： G.-x.Shen G.-K.Tan G.-J.lai Fluid Mechanics Institute Beihang University

A bionic ex.erimental platform was designed for the purpose of investigating time accurate three-dimensional flow field, using digital particle image velocimetry （DSPIV）. The wake behind the flapping trail of a robotic fish model was studied at high spatial resolution. The study was performed in a water channel. A robot fish model was designed and built. The model was fix.d onto a rigid support frame- work using a cable-supporting method, with twelve stretched wires. The entire tail of the model can perform prescribed motions in two degrees of freedom, mainly in carangiform mode, by driving its afterbody and lunate caudal fin respectively. The DSPIV system was set up to operate in a trans- lational manner, measuring velocity field in a series of parallel slices. Phase locked measurements were repeated for a number of runs, allowing reconstruction of phase average flow field. Vortex.structures with phase history of the wake were obtained. The study reveals some new and complex.three-dimensional flow structures in the wake of the fish, including ＂reverse hairpin vortex. and ＂reverse Karman S-H vortex.rings＂, allowing insight into physics of this complex.flow.

关键词： Fish swimming 3D flow structure Unsteadyhydrodynamics DSPIV measurement - Vortex.ring

Validation of Growth and Nutrient Uptake Models for Tomato on a Gravelly South Florida Soil Under Greenhouse Conditions

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Pedosphere 2011年第1期21卷 46-55页

作者： D. A. CHIN x. H. FAN Y. C. LI Department of Civil and Environmental Engineering University of Miami Coral Gables FL 33124 (USA) Tropical Research and Education Center Soil and Water Science Department University of Florida Homestead FL 33031 (USA)

The Soil and Water Assessment Tool(SWAT) has been widely used throughout the world to model crop growth and nutrient uptake in various types of soils.A greenhouse ex.eriment was performed to validate the process equations embedded in SWAT for describing the growth and nutrient uptake of tomatoes in south *** scaled growth curve of greenhouse-grown tomatoes was in close agreement with the theoretical model for field conditions,with the scaling factors being the max.mum canopy height and the potential heat ***,the scaled leaf area index.lai) growth curve and the scaled root depth curve for greenhousegrown tomatoes agreed with the SWAT functions,with the scaling factors being the max.mum lai and max.mum root *** greenhouse ex.eriment confirmed that the growth of biomass is a linear function of the intercepted photosynthetically active *** fractions of nutrients in the plant biomass under greenhouse conditions were found to be on the order of 60% of those fractions observed in the *** of the initial P distribution(0.2 mg kg -1),initial ratio of mineral stable P to mineral active P(50:1),and initial ratio of humic N to humic P(2.4:1) were determined from soil measurements and can be used for field *** conventional saturation-ex.ess model for soil-water percolation was used to predict the movement of water in the top 10 cm of the greenhouse containers and the results agreed well with measurements.

关键词： container plants crop modeling Krome soil nitrogen phosphorus

Comparative Molecular Field Analysis on a Set of New Herbicidal Sulfonylurea Compounds

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Chinese Chemical Letters 1997年第6期8卷 503-504页

作者： Liu, J Wang, x.Ma, Y Li, ZM lai, CM Jia, GF Wang, Lx NANKAI UNIV STATE LAB ELEMENTOORGAN CHEMELEMENTOORGAN CHEM INSTTIANJIN 300071PEOPLES R CHINA

In this paper Comparative Molecular Field Analysis (CoMFA) method was applied to study the three-dimensional quantitative structure activity relationship (3D-QSAR) on a set of new herbicidal sulfonylureas. We optimize... 详细信息

关键词： Comparative Molecular Field Analysis on a Set of New Herbicidal Sulfonylurea Compounds

EFFECT OF Cu-Ni CONTENT ON THE CORROSION RESISTANCE OF(Cu-Ni)/(10NiO-90NiFe_2O_4)CERMET INERT ANODE FOR ALUMINUM ELECTROLYSIS

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Acta Metallurgica Sinica(English Letters) 2008年第1期21卷 72-78页

作者： Z.L. Tian Y.Q. lai J. Li Y.x. Liu School of Metallurgical Science and Engineering Central South University Changsha 410083 China

（Cu-Ni）/（10NiO-90NiFe204） cermet inert anodes containing metal Cu-Ni0, 5, 10, 15 and 20 wt pct were prepared and their corrosion resistance to Na3AlF6-Al2O3 melts was investigated. The results indicate that the content of metal Cu-Ni has little effect on the steady-state concentration of Ni in the electrolyte and the values could not be used to effectively differentiate their corrosion resistance. The steady-state concentration of Fe decreases from 304×10^-6 to 168×10^-6 and that of Cu increases from 21×10^-6 to 71×10^-6 with the content of metal Cu-Ni increasing from 0 to 20 wt pct. Post-ex.mination shows that metallic phase Cu-Ni is corroded preferentially during electrolysis and many pores are left at the anode surface. Considering the corrosion resistance and electrical conductivity, the cermet containing metal Cu-Ni 5 wt pct should be selected and studied further.

关键词： Aluminum electrolysis Inert anode NiFe2O4 based cermet Corrosion resistance

Anisotropic Inter-granular Corrosion Behaviors and Microstructures of AlMgSiCu Alloy Sheets Made by Thermal–Mechanical Treatments

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Acta Metallurgica Sinica(English Letters) 2022年第2期35卷 275-284页

作者： L.M.Liu Y.x.lai C.L.Wu Z.Zhang J.H.Chen Center for High-Resolution Electron Microscopy College of Materials Science and EngineeringHunan UniversityChangsha 410082China

This study investigates the microstructure and local corrosion behavior of an Al-Mg-Si-Cu alloy,which has been subjected to cold-rolling with different deformation strain ratios(DSRs)and followed by artificial *** corrosion tests show that peak-aged samples with a small DSR(5-10%)are sensitive to inter-granular corrosion(IGC)along both the normal and rolling *** the DSR increases to medium strength(20-40%),IGC sensitivity decreases along both directions and corrosion propagates *** the DSR is 60-80%,IGC sensitivity along the normal direction continues to decrease,but increases along the rolling direction,indicating pronounced corrosion *** characterization reveals the decreased IGC sensitivity is mainly attributed to a reduction in element segregation at high-angle grain boundaries and the kinked and discontinuous grain boundary corrosion *** increased IGC sensitivity along the rolling direction could be related to the significantly flattened grains.

关键词： Al alloys Local corrosion Anisotropy Transmission electron microscopy(TEM) Electron backscattering diffraction(EBSD)

Structures and formation mechanisms of dislocation-induced precipitates in relation to the age-hardening responses of Al-Mg-Si alloys

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Journal of Materials Science & Technology 2020年第6期41卷 127-138页

作者： Y.x.lai W.Fan M.J.Yin C.L.Wu J.H.Chen Center for High-Resolution Electron Microscopy College of Materials Science&EngineeringHunan UniversityChangsha 410082China Electron Microscopy Center Shenzhen UniversityShenzhen 518060China

In the slightly deformed Al-Mg-Si alloys,dislocation-induced precipitates are frequently observed,and they usually line up,forming sophisticated precipitation *** atomic-resolution electron microscopy in association with hardness measurements,we systematically investigated these precipitates in relation to the age-hardening responses of the *** study reveals that the majority of dislocation-induced complex.precipitates are actually short-range ordered while long-range disordered polycrystalline precipitates and multiphase composite precipitates,including polycrystalline U2 precipitates,B’/U2,B’-2/U2,B’/B’-2/U2 and’/U2 composite *** is suggested that the formation of these complex.precipitates is mainly owing to a high nucleation rate and rapid growth of different precipitate phases parallel to the associated dislocation *** dislocation-induced precipitates consume more Mg than Si from the matrix.and have a high formation kinetics,they will have different impacts on the matrix.precipitation in different types of Al-Mg-Si *** results further demonstrate that for the"normally-β"-hardened"alloy,their formation leads to a coarser precipitate microstructure in the matrix.whereas for the"normally-β’-hardened"alloy,their formation reverses the precipitation pathway in the matrix.resulting in a reduced age-hardening potential of the former alloy and an improved age-hardening potential of the latter alloy.

关键词： Al-Mg-Si alloys Precipitation Dislocation Age-hardening Electron microscopy