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Strategies for improving ductility of ordered intermetallics

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Progress in Natural Science:Materials International 2016年第1期26卷 1-12页

作者： Z.b.Jiao J.H.Luan C.t.Liu Center for Advanced Structural Materials Department of Mechanical and Biomedical Engineering College of Science and Engineering City University of Hong Kong

ordered intermetallics possess attractive high-temperature properties; however, low ductility and brittle fracture limit their use as engineering materials in many cases. this paper provides a comprehensive review on the recent progress in the development of ductile ordered intermetallics and summarizes the strategies used to improve the tensile ductility of ordered intermetallics, including control of ordered crystal structures,engineering grain-boundary structure and chemistry, eliminating environmental embrittlement, microstructure optimization, control of phase stability, and promoting transformation-/twining-induced plasticity. the basic ideas and related mechanisms underlying these ductilizing strategies are discussed. In addition, a brief mention of the current use of intermetallic alloys for structural and corrosion applications is made.

关键词： ordered intermetallics Ductility Ductilizing strategy Microstructure Alloy design

Real-time wavelength routing based on bragg reflection with integrated forward Raman for long-reach networks

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optoelectronics Letters 2020年第1期16卷 40-44页

作者： G.M.Isoe t.b.Gibbon South African Radio Astronomy observatory(SARAo) Cape Town 7925South Africa Centre for broadband Communication Nelson Mandela UniversityPort Elizabeth 6031South Africa

We experimentally demonstrate the all-optical efficient technique for dynamic full-duplex wavelength routing and reach extension through adoption of passive fibre bragg grating(FbG),energy efficient vertical cavity surface emitting lasers(VCSELs)and high gain forward Raman *** this study,two VCSEL channels at 1549.62 nm and 1550.01 nm are directly modulated with a 8.5 Gbit/s data signal each,and transmitted over 25.5 km fibre to a passive single mode FbG-based wavelength routing *** precise wavelength selectivity of the FbG is exploited to achieve all-optical real-time wavelength routing of the 1549.62 nm VCSEL channel with a maximum insertion loss of 22.1 *** 1550.01 nm channel is transmitted through the FbG with a maximum penalty of 1.03 *** utilizing the 7.2 db flat gain of a forward Raman pump,the routed 1549.62 nm VCSEL channel is transmitted over 76.7 km fibre with a maximum penalty of 3.84 db at bit error rate(bER)of *** technique is all-optical,power efficient as it employs passive FbG and circulators and has low cross talk allied to precise wavelength selectivity of the technique.

关键词： passive pump fibre

Characterization of ion irradiated silicon surfaces ablated by laser-induced breakdown spectroscopy

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Chinese Physics b 2018年第8期27卷 505-510页

作者： t Iqbal M Abrar M b tahir M Seemab A Majid S Rafique Department of Physics Faculty of Sciences University of Gujrat Hafiz Hayat Campus Department of Physics Hazara University Mansehra Department of Physics University of Engineering and Technology (UET)Lahore Pakistan

Low energy metallic ions, generated by a Q-switched Nd：YAG laser （1064-nm wavelength, 10-mJ energy, 9-nm 12-ns-pulse width, 1011 W/cm2 intensity） irradiated on a silicon substrate to modify various properties, such as electrical, morphological, and structural modifications. thomson parabola technique is used to calculate the energy of these metallic ions whereas the electrical conductivity is calculated with the help of Four-point probe. Interestingly circular tracks forming chain like damage trails are produced via these energetic ions which are carefully examined by optical microscopy. It is observed that excitation, ionization, and cascade collisions are responsible for surface modifications of irradiated samples. Four-point probe analysis revealed that the electrical conductivity of substrate has reduced with increasing trend of atomic number of irradiated metallic ions （A1, ti, Cu, and Au）. the x-ray diffraction analysis elucidated the crystallographic changes leading to reduction of grain size of N-type silicon substrate, which is also associated with the metallic ions used. the decreasing trend of conductivity and grain size is due to thermal stresses, scattering effect, structural imperfections, and non-uniform conduction of energy absorbed by substrate atoms after the ion irradiation.

关键词： ablation thomson parabola technique four-point probe

Enhanced green emission from La＿(0.4)F＿3:Ce＿(0.45),tb＿(0.15)/tio＿2 core/shell structure

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Journal of Rare Earths 2015年第1期33卷 20-26页

作者： t.K.Srinivasan b.S.Panigrahi N.Suriyamurthy P.K.Parida b.Venkatraman Indira Gandhi Centre for Atomic Research Kalpakkam–603102 India

Nano sized La0.4F3：Ce0.45,tb0.15（core）, La0.4F3：Ce0.45,tb0.15（ti o2）（core） shell, La0.55F：Ce0.45, and La0.85F3：tb0.15 particles were synthesized by adopting co-precipitation technique in acidic environment and coated with ti o2 to form a core-shell structure by adopting a mechanical dispersion method at room temperature. the synthesized materials were characterized using X-ray diffraction（XRD）, transmission electron microscopy（tEM）, Fourier transform infrared spectroscopy（FtIR）, ultraviolet-visible spectroscopy（UV-Vis） absorption, photoluminescence and lifetime spectroscopy. the crystal structure of La0.4F3：Ce0.45,tb0.15 remained the same as La F3 after being doped with Ce and tb ions but with a slight decrease in the lattice parameter. tEM image confirmed the formation of a core-shell structure. the La0.4F3：Ce0.45,tb0.15/ti o2 exhibited tb3＋ fluorescence enhancement by a factor of 1.76. Scintillation from the synthesized materials was also observed under X-ray excitation.

关键词： core-shell cerium terbium luminescence lanthanum fluoride scintillation rare earths

Virtual Australia:its key elementsknow,think,communicate

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International Journal of Digital Earth 2008年第1期1卷 66-87,I0005页

作者： b.thompson t.o.Cha R.Slee P.Kinne A.Jahshan P.Woodgate I.bishop D.McKenzie Spatial Information Infrastructure Department of Sustainability and EnvironmentLevel 13Marland House570 Bourke StreetMelbourne Victoria 3000Australia oracle Fusion Middleware Sales Oracle Corporation Asia Pacific4 Julius AvenueNorth Ryde NSW 2113Australia open Spatial technologies Pty Ltd 433 Logan RoadStones Corner QLD 4120Australia Australian Cooperative Research Centre for Spatial Information 723 Swanston StreetUniversity of MelbourneVictoria 3010Australia Department of Geomatics The University of Melbourne VictoriaAustralia

Virtual Australia is not a well-defined or agreed *** discussion paper conceptualises Virtual Australia as a‘virtual[digital]model containing and representing all non-trivial objects and their contextual environmentfrom blue sky to bedrockin real world Australia’.It describes a scenario for Virtual Australia,one or two decades from now,in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a‘Supranet’.It then examines the concept of the‘Supranet’a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real timeand develops and discusses three principal characteristics of the Supranet:the ability to have or collect specific information(know);the ability to process information(think);and the ability to communicate that ***,in the near future,any or all non-trivial devices are to some extent able to know,think and communicate,the potential for object autonomy will be realised.

关键词： virtual spatial supranet digital information sensors motes innovation Australia

Impacts of Soil Additives on Crop Yield and C-Sequestration in Post Mine Substrates of Lusatia,Germany

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Pedosphere 2012年第3期22卷 343-350页

作者： A.RoDIoNoV S.NII-ANNANG o.bENS M.tRIMboRN S.SCHILLEM b.U.SCHNEIDER t.RAAb R.F.HttL Institute of Crop Science and Resource Conservation University of BonnBonn 53115 (Germany) Faculty of Environmental Science and Process Engineering Brandenburg University of TechnologyCottbus 03046 (Ger-many) German Research Centre for Geosciences GFZ Potsdam 14473 (Germany)

opencast lignite mining in the Lusatia region of Germany has resulted in large scale landscape disturbances, which require suitable recultivation techniques in order to promote plant growth and establishment in the remaining nutrient-poor substrates with low water-holding capacity. thus, the effects of two commercial soil additives （CSA）, a hydrophilic polymer mixed with volcanic rock flour and bentonite （a-CSA）, and digester solids from biogas plants enriched with humic acids and bentonite （b-CSA）, on soil organic carbon （SoC） storage, plant yields and root biomass were assessed after cultivating perennial crops （Dactylis 9lornerata L.） in monoculture and Helianthus annuus L.-brassica napus L. in crop rotation systems. the CSA were incorporated into the top 20 cm soil depth using a rotary spader. the results indicated that a-CSA led to a significant increase in plant yield during the first year, and improved root biomass in the following year. As a result, SoC stocks increased, especially in the 0 10 cm soil layer. No significant sequestration of additional SoC was observed on b-CSA-amended plots at the end of both years. bulk density values decreased in all treatments under the monoculture system. It can be concluded that application of a-CSA enhanced soil water availability for plant uptake and consequently promoted plant growth and organic carbon sequestration. the relative enrichment of organic matter without effects on water-holding capacities of b-CSA treatments suggested that it was not suitable for rapid land reclamation.

关键词： bulk density organic C inputs polyacrylate soil organic carbon water-holding capacity

Atomistic simulations of friction at an ice−ice interface

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Friction 2013年第3期1卷 242-251页

作者： N.SAMADASHVILI b.REISCHL t.HYNNINEN t.ALA-NISSILÄ A.S.FoStER CoMP Centre of Excellence Aalto University School of ScienceDepartment of Applied PhysicsP.O.Box 11100FI-00076 AaltoFinland Department of Physics Tampere University of TechnologyP.O.Box 692FI-33101 TampereFinland

Even though the slipperiness of ice is important both technologically and environmentally and often experienced in everyday life,the nanoscale processes determining ice friction are still *** study the friction of a smooth ice-ice interface using atomistic simulations,and especially consider the effects of temperature,load,and sliding *** this scale,frictional behavior is seen to be determined by the lubricating effect of a liquid premelt layer between the sliding ice *** general,increasing temperature or load leads to a thicker lubricating layer and lower friction,while increasing the sliding velocity increases friction due to viscous shear.

关键词： ice friction nanoscale molecular dynamics tIP4P/ice

Numerical simulation of self-similar thermal convection from a spinning cone in anisotropic porous medium

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Journal of Hydrodynamics 2016年第2期28卷 184-194页

作者： o. Anwar bEG M. J. UDDIN t. bEG R. Reddy GoRLA Spray Research Group Petroleum and Gas Engineering Division Room G77 Newton Building School of Computing Science and Engineering (CSE) University of Salford M54WT UK Department of Mathematics American International University-Bangladesh Dhaka Bangladesh Engineering Mechanics Associates Dickenson Road Manchester M 16 England UK Department Mechanical Engineering Cleveland State University Cleveland Ohio USA

Self-similar steady natural convection thermal boundary layer flow from a rotating vertical cone to anisotropic Darcian porous medium is investigated theoretically and numerically. the transformed non-dimensional two-point boundary value problem is reduced to a system of coupled, highly nonlinear ordinary differential equations, which are solved subject to robust surface and free stream boundary conditions with the MAPLE 17 numerical quadrature software. Validation with earlier non-rotating studies is included, and also further verification of rotating solutions is achieved with a variational finite element method （FEM）. the rotational （spin） parameter emerges as an inverse function of the Grashof number. the influence of this parameter, primary Darey number, secondary Darcy number and Prandtl number on tangential velocity and swirl velocity, temperature and heat transfer rate are studied in detail. It is found that the dimensionless tangential velocity increases whilst the dimensionless swirl velocity and temperature decrease with the swirl Darcy number, tangential Darcy number and the rotational parameters. the model finds applications in chemical engineering filtration processing, liquid coating and spinning cone distillation columns.

关键词： self-similarity spinning cone finite element method (FEM) anisotropic porous medium heat transfer MAPLE FEM

Geostatistical modelling and mapping of nematode-based soil ecological quality indices in a polluted nature reserve

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Pedosphere 2021年第5期31卷 670-682页

作者： Israel o.IKoYI Gerard b.M.HEUVELINK Ron G.M.DE GoEDE Wageningen University&Research Soil Biology GroupWageningen 6700 AA(The Netherlands) Current address:University of Limerick School of Natural SciencesDepartment of Biological SciencesLimerick V94T9PX(Ireland) Wageningen University&Research Soil Geography and Landscape GroupWageningen 6700 AA(The Netherlands)

Nematodes are indicators of soil quality and soil *** of the relationships between nematode-based soil quality indices and environmental properties is beneficial for assessing environmental threats on soil *** study evaluated the spatial distribution of nematode-based soil quality indices in a 23-ha heavy metal-polluted nature reserve using geostatistical *** expected that a selection of abiotic soil properties(pH and moisture,clay,organic matter,cadmium(Cd),and zinc(Zn)contents)could explain a significant portion of the spatial variation of the indices and that regression kriging could more accurately model their spatial distribution than ordinary kriging.A stratified simple random sampling scheme was used to select 80 locations where soil samples were taken to extract nematodes and derive the *** area had a distinct gradient in soil properties with Cd and Zn content ranging from 0.07 to 68.9 and 5.3 to 1329 mg kg^(-1),*** regression models were fitted to describe the relationships between the indices and soil *** also modelling the spatial correlation structure of regression residuals using spherical semivariograms,regression kriging was used to produce maps of the *** regression models explained between 21% and 44% of the total original variance in the *** pH was a significant explanatory variable in almost all cases,while heavy metal conent had a remarkably low *** some cases,the regression residuals had spatial *** validation indicated that in all cases,regression kriging performed slightly better because of having lower values of the root mean square prediction error and a mean prediction error closer to zero than ordinary *** study showed the importance of soil properties in explaining the spatial distribution of biological soil quality indices in ecological risk assessment.

关键词： ecological risk assessment heavy metals model validation regression kriging semivariance analysis soil property spatial structure