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International Journal of Biomathematics 2017年第6期10卷 73-97页

作者： M. Sivak.mar k. Balachandran k. k.ruppiah Bharathiar University Coimbatore 641046 Tamilnadu India Department of Mathematics Bharathiar University Coimbatore 641046 Tamilnadu India

In this paper, we consider a diffusive density-dependent predator-prey model with Crowley-Martin functional responses subject to Neumann boundary condition. We ana- lyze the stability of the positive equilibrium and the existence of spatially homogeneous and inhomogeneous periodic solutions through the distribution of the eigenvalues. The direction and stability of Hopf bifurcation are determined by the normal form theory and the center manifold theory. Finally, numerical simulations are given to verify our theoretical analysis.

关键词： Stability and bifurcation analysis diffusive predator-prey model Smithgrowth Crowley Martin functional response.

Immune stress and diet influence reproductive fitness in male tuatara (Sphenodon punctatus)

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CURRENT ZOOLOGY 2024年第6期70卷 786-794页

作者： Lamar, Sarah k. Ormsby, Diane k. Nelson, Nicola J. Victoria Univ Wellington Sch Biol Sci Level 2Te Toki A Rata Bldg Wellington 6012 New Zealand Victoria Univ Wellington Ctr Biodivers & Restorat Ecol Level 2Te Toki A Rata Bldg Wellington 6012 New Zealand

The theoretical trade-off between immune and endocrine investment in mating animals has received mixed empirical support, particularly in reptiles. We investigated the relationship between male sexual characteristics, diet, and immune response to stress in an island population of tuatara (Sphenodon punctatus) across two mating seasons. Tuatara are promiscuous, with a highly sk.wed mating system where males face significant competition for access to mates and postcopulatory competition for fertilization success. We found that tuatara sperm viability and swim speed were negatively associated with male body condition and the ratio of heterophils to lymphocytes. Additionally, sperm swim speed was negatively associated with spine area, mite load, and the total number of circulating white blood cells, but was positively associated with tick.number. This is lik.ly a function of social dynamics in this system where larger male size predicts greater spatial overlap with potential rivals and increased tick.load. Because the production of sexual characteristics may be costly, we also investigated the effect of diet on sperm quality. We did not identify an association between diet and sperm viability. However, sperm swim speed was negatively associated with carbon-13 and positively associated with nitrogen-15. We suspect that these results reflect the influence of seabird-based nutrients in this island ecosystem, particularly polyunsaturated fatty acid, and antioxidant damage on tuatara sperm. In total, these results provide evidence of a trade-off between pre- and post-copulatory sexual characteristics and the immune and endocrine systems in male tuatara.

关键词： reproductive fitness reptiles sexual selection sperm characteristics tuatara

Effects of heavy metals (Pb^(2+) and Cd^(2+)) on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium Synechocystis sp. PCC 6803

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Chinese Journal of Oceanology and Limnology 2009年第2期27卷 383-388页

作者： k. k. I. U. Arunak.mara 张学成 College of Marine Life Sciences Ocean University of China Department of Crop Science Faculty of AgricultureUniversity of Ruhuna

The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism k.own for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb^2＋ and Cd〉（0, 0.5, 1, 2, 4, 6 and 8 mg/L）. The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 cells became evident with the increased （〉4 mg/L Pb^2＋） metal concentration. The photosynthetic apparatus （thylak.id membranes） were found to be the worst affected. Deteriorated or completely destroyed thylak.id membranes have made large empty spaces in the cell interior. In addition, at the highest concentration （8 mg/L pb^2＋）, the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations （0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L pb^2＋）, both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents （chlorophyll a, 13 carotene and phycocyanin） were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb^2＋, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, 13 carotene and phycocyanin respectively over the control. Corresponding reductions for the same CdZ＋concentrations were 57.83, 48.94 and 56.90%. Lethal concentration （96 h LC50） values （3.47 mg/L Cd^2＋ and 12.11 mg/L Pb^2＋） indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd^2＋ than Pb^2＋.

关键词： growth pigment contents Synechocystis sp. PCC 6803 ultrastructure

Surface Acidity of Amorphous Aluminum Hydroxide

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Acta Geologica Sinica(English Edition) 2006年第2期80卷 206-211页

作者： k. FUk.SHI k. TSUk.MURA H. YAMADA Research Center for Deep Geological Environments Ecomaterials Center

The surface acidity of synthetic amorphous AI hydroxide was determined by acid/base titration with several complementary methods including solution analyses of the reacted solutions and XRD characterization of the reacted solids. The synthetic specimen was characterized to be the amorphous material showing four broad peak. in XRD pattern. XRD analyses of reacted solids after the titration experiments showed that amorphous AI hydroxide rapidly transformed to crystalline bayerite at the alk.line condition （pH〉10）. The solution analyses after and during the titration k.p=^aAl^3＋/aH^＋^3 ,was 10^10.3. The amount of consumption of added acid or base during the titration experiment was attributed to both the protonation/deprotonation of dissolved AI species and surface hydroxyl group. The surface acidity constants, surface hydroxyl density and specific surface area were estimated by FITEQL 4.0.

关键词： amorphous AI hydroxide acid/base titration solubility crystallization surface acidity constants surface site density FITEQL

Geometry optimization of a barrel silicon pixelated track.r

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Chinese Physics C 2017年第8期41卷 118-124页

作者：刘清源王萌 Marc winter School of Physics and k.y Laboratory of Particle Physics and Particle Irradiation(MOE) Shandong UniversityJinan 250100China Universite de Strasbourg IPHC-CNRS23 rue du Loess67037 StrasbourgFrance

We have studied optimization of the design of a barrel-shaped pixelated track.r for given spatial boundaries. The optimization includes choice of number of layers and layer spacing. Focusing on track.ng performance only,momentum resolution is chosen as the figure of merit. The layer spacing is studied based on Gluck.tern＇s method and a numerical geometry scan of all possible track.r layouts. A formula to give the optimal geometry for curvature measurement is derived in the case of negligible multiple scattering to deal with trajectories of very high momentum particles. The result is validated by a numerical scan method, which could also be implemented with any track.fitting algorithm involving material effects, to search for the optimal layer spacing and to determine the total number of layers for the momentum range of interest under the same magnetic field. The geometry optimization of an inner silicon pixel track.r proposed for BESIII is also studied by using a numerical scan and these results are compared with Geant4-based simulations.

关键词： track.r geometry optimization optimal spacing numerical scan least squares k.lman filter initialization BESIII silicon pixel track.r

SURFACE MODIFICATION OF TITANIUM FILMS WITH SODIUM ION IMPLANTATION:SURFACE PROPERTIES AND PROTEIN ADSORPTION

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Acta Metallurgica Sinica(English Letters) 2007年第2期20卷 148-156页

作者： k. Y. Cai College of Bioengineering Chong Qing University Chongqing 400044 China

Sodium implanted titanium films with different ion doses were characterized to correlate their ion implantation parameters. Native titanium films and ion implanted titanium films were characterized with combined techniques of X-ray photoelectron spectroscopy （XPS）, atomic force microscopy （AFM）, and light microscopy （LM）. The surface presented increased sodium concentration on treated titanium films with ion dose increasing, except for the group with the highest ion dose of 4×10^17ions/cm^2. XPS depth profiling displayed that sodium entered titanium film around 25-50nm depth depending on its implantation ion dose. AFM characterization showed that sodium ion implantation treatment changed the surface morphology from a relatively smooth titanium film to rough surfaces corresponding to different implantation doses. After sodium implantation, implanted titanium films presented big particles with island structure morphology. The surface morphology and particle growth displayed the corresponding trend. Fibrinogen adsorption on these titanium films was performed to correlate with the surface properties of treated titanium films. The results show that protein adsorption on ion-implanted samples with dose of 2×10^17 and 4×10^17 are statistically higher （p 〈0.01） than samples treated with dose of 5×10^16 and 1×10^17, as well as the control samples.

关键词： titanium film sodium ion implantation protein adsorption surface characterization

Studies on solar flat plate collector evaporation systems for tannery effluent(soak.liquor)

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1870-1877页

作者： SRITHAR k. MANI A. Department of Mechanical Engineering Thiagarajar College of Engineering Madurai 625015 India Department of Mechanical Engineering Indian Institute of Technology Madras Chennai 600036 India

Heat and mass transfer analysis of an incompressible, laminar boundary layer over solar flat plate collector evapora- tion systems for tannery effluent (soak.liquor) is investigated. The governing equations are solved for various liquid to air velocity ratios. Profiles of velocity, temperature and concentration as well as their gradients are presented. The heat transfer and mass transfer coefficients thus obtained are used to evaluate mass of water evaporated for an inclined fibre-reinforced plastic (FRP) solar flat plate collector (FPC) with and without cover. Comparison of these results with the experimental performance shows encouraging trend of good agreement between them.

关键词： Boundary layer Solar flat plate collector Fibre-reinforced plastic flat plate collector Open flat plate collector,Tannery effluent treatment Pollution

Integrated numerical model for vegetated surface and saturated subsurface flow interaction

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Applied Mathematics and Mechanics(English Edition) 2012年第7期33卷 881-898页

作者： k. S. ERDURAN Department of Civil Engineering Faculty of Engineering University of Nigde Department of Civil Engineering College of Engineering American University of Sharjah

The construction of an integrated numerical model is presented in this paper to deal with the interactions between vegetated surface and saturated subsurface flows. A numerical model is built by integrating the previously developed quasi-three-dimensional （Q3D） vegetated surface flow model with a two-dimensional （2D） saturated groundwater flow model. The vegetated surface flow model is constructed by coupling the explicit finite volume solution of 2D shallow water equations （SWEs） with the implicit finite difference solution of Navier-Stok.s equations （NSEs） for vertical velocity distribution. The subsurface model is based on the explicit finite volume solution of 2D saturated groundwater flow equations （SGFEs）. The ground and vegetated surface water interaction is achieved by introducing source-sink.terms into the continuity equations. Two solutions are tightly coupled in a single code. The integrated model is applied to four test cases, and the results are satisfactory.

关键词： vegetated surface flow saturated groundwater flow flow interaction tightcoupling finite volume method finite difference method flow resistance

Nonlinear convection in a non-Darcy porous medium

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Applied Mathematics and Mechanics(English Edition) 2010年第5期31卷 565-574页

作者： M. k. PARTHA Department of Mathematics Malnad College of Engineering

In this paper, the natural convection in a non-Darcy porous medium is studied using a temperature-concentration-dependent density relation. The effect of the two parameters responsible for the nonlinear convection is analyzed for different values of the inertial parameter, dispersion parameters, Rayleigh number, Lewis number, Soret number, and Dufour number. In the aiding buoyancy, the tangential velocity increases steeply with an increase in the nonlinear temperature parameter and the nonlinear concentration parameter when the inertial effect is zero. However, when the inertial effect is non-zero, the effect of the nonlinear temperature parameter and the nonlinear concentration parameter on the tangential velocity is marginal. The concentration distribution varies appreciably and spreads in different ranges for different values of the double dispersion parameters, the inertial effect parameter, and also for the parameters which control the nonlinear temperature and the nonlinear concentration. Heat and mass transfer varies extensively with an increase in the nonlinear temperature parameter and the nonlinear concentration parameter depending on Dacry and non-Darcy porous media. The variation in heat and mass transfer when all the effects, i.e., the inertial effect, double dispersion ef- fects, and Soret and Dufour effects, are simultaneously zero and non-zero. The combined effects of the nonlinear temperature parameter, the nonlinear concentration parameter and buoyancy are analyzed. The effect of the nonlinear temperature parameter and the nonlinear concentration parameter and also the cross diffusion effects on heat and mass transfer are observed to be more in Darcy porous media compared with those in non- Darcy porous media. In the opposing buoyancy, the effect of the temperature parameter is to increase the heat and mass transfer rate, whereas that of the concentration parameter is to decrease.

关键词： non-Darcy porous medium natural convection double dispersion

Hydrogenic Donor in a Spherical Quantum Dot with Different Confinements

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Chinese Physics Letters 2009年第8期26卷 309-312页

作者： A. John Peter k. Navaneethak.ishnan Govt. Arts College Melur-625 106 Madurad India Madurai k.maraj-University Madurai-625 021 India

Binding energies of a hydrogenic donor in a spherical GaAs quantum dot surrounded by Ga1-xA4xAs matrix are calculated. The results are presented for realistie barrier heights corresponding to different values of x （x 〈 0.4）. The calculations are performed under two different conditions：（i） a spherical dot with square well confinement and （ii） a dot with parabolic potential well confinement. The results show that （i） the donor ionization energies are always higher under parabolic confinement as compared to a dot of the same radius under square well confinement and （ii） the oscillator strengths coupling ground state with excited states are two orders larger under parabolic confinement. Our results are in agreement with the results of other researchers.

关键词： ELECTRON donor-acceptor complexes QUANTUM dots BINDING energy OSCILLATOR strengths PLASMA confinement QUANTUM wells GALLIUM arsenide semiconductors