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A case f.r mantle plumes

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Chinese Science Bulletin 2005年第15期50卷 1541-1554页

作者： Geof.rey f. Davies Research School of.Earth Sciences Australian National University Canberra ACT 0200 Australia

The existence of.at least several plumes in the Earth’s mantle can be inf.rred with f.w assumptions f.om well-established observations. As well, thermal mantle plumes can be predicted f.om well-established and quanti-f.ed f.uid dynamics and a plausible assumption about the Earth’s early thermal state. Some additional important ob-servations, especially of.f.ood basalts and rif.-related mag-matism, have been shown to be plausibly consistent with the physical theory. Recent claims to have detected plumes using seismic tomography may comprise the most direct evidence f.r plumes, but plume tails are likely to be dif.icult to resolve def.nitively and the claims need to be well tested. Although signif.cant questions remain about its viability, the plume hypothesis thus seems to be well worth continued investiga-tion. Nevertheless there are many non-plate-related mag-matic phenomena whose association with plumes is unclear or unlikely. Compositional buoyancy has recently been shown potentially to substantially complicate the dynamics of.plumes, and this may lead to explanations f.r a wider range of.phenomena, including “headless” hotspot tracks, than purely thermal plumes.

关键词：地球覆盖物羽毛流体动力学热量对流火山

Variation in growth potential between hybrid clones of.Eucalyptus trees in eastern South Af.ica

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Journal of.f.restry Research 2017年第6期28卷 1154-1164页

作者： Sileshi f. Melesse Temesgen Zewotir School of.Mathematics Statistics and Computer ScienceUniversity of KwaZulu-Natal Pietermaritzburg South Africa

Growth of.commercial f.restry is highly dependent on the availability of.f.st-growing planting materials. Consequently, the ef.icient utilization of.f.stgrowing plantations can greatly impact productivity. The objectives of.this study were to evaluate variations in the growth potential of.two clones and to estimate the average stem radial growth advantage of.a f.st-growing clone using data obtained f.om Sappi landholdings in eastern South Af.ica and a mixed modelling approach that permits the incorporation of.covariance structure into the statistical model. During the f.rst 2 years of.growth, the stem radius of.nine trees each of.two clones was measured using dendrometer attached to the tree. A second-degree f.actional polynomial model was chosen to show the f.nctional relationship between stem radius and tree age. Growth of.the two hybrid clones dif.ered signif.cantly. The Eucalyptus grandis×Eucalyptus urophylla clone grew f.ster than the E. grandis×camaldulensis clone, indicating better genetic potential f.r rapid growth and yield. This study can be considered as starting point to f.rther compare the potential f.r rapid growth of.several hybrid clones using the longitudinal data modelling approach.

关键词： Covariance f.nction Dendrometer trial Growth rate Loess Longitudinal study Random slope

Soil Properties in Conif.rous f.rest Stands Along a f.y Ash Deposition Gradient in Eastern Germany

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Pedosphere 2005年第6期15卷 681-694页

作者： S. KLOSE f. MAKESCHIN Institute of.Soil Science Faculty of Forest Geo and Hydro Sciences Dresden University of Technology P.O. 1117 D-01735 Tharandt (Germany)

Physical, chemical, and microbial properties of.f.rest soils subjected to long-term f.y ash depositions were analyzed in spruce (Picea abies (L.) Karst.) stands of.eastern Germany on three f.rest sites along an emission gradient of.3 (high input), 6, and 15 km (low input) downwind of.a coal-f.red power plant. Past emissions resulted in an atypical high mass of.mineral f.y ash constituents in the organic horizons at the high input site of.128 t ha-1 compared to 58 t ha-1 at the low input site. Magnetic susceptibility measurements proved that the high mineral content of.the f.rest f.oor was a result of.f.y ash accumulation in these f.rest stands. f.y ash deposition in the organic horizons at Site I versus III signif.cantly increased the pH values, ef.ective cation exchange capacity, base saturation and, with exception of.the L horizon, concentrations of.mobile heavy metals Cd, Cr, and Ni, while stocks of.organic C generally decreased. A principal component analysis showed that organic C content and base status mainly controlled soil microbial biomass and microbial respiration rates at these sites, while pH and mobile f.actions of.Cd, Cr, and Ni governed enzyme activities. Additionally, it was hypothesized that long-term f.y ash emissions would eventually destabilize f.rest ecosystems. Theref.re, the results of.this study could become a usef.l tool f.r risk assessment in f.rest ecosystems that were subjected to past emissions f.om coal-f.red power plants.

关键词： conif.rous f.rests f.y ash deposition magnetic susceptibility microbial biomass mobile heavy metal f.action

Teichmller space of.negatively curved metrics on complex hyperbolic manif.lds is not contractible

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Science China Mathematics 2017年第4期60卷 569-580页

作者： f.RRELL f. Thomas SORCAR Gangotryi Yau Mathematical Sciences Center and Department of.Mathematical Sciences Tsinghua University Beijing 100084 China Department of.Mathematics Ohio State University Columbus OH 43210 USA

We prove that f.r all n = 4k- 2 and k 2 there exists a closed smooth complex hyperbolic manif.ld M with real dimension n having non-trivial π1(T<0(M)). T<0(M) denotes the Teichm¨uller space of.all negatively curved ... 详细信息

We prove that f.r all n = 4k- 2 and k 2 there exists a closed smooth complex hyperbolic manif.ld M with real dimension n having non-trivial π1(Tf.all negatively curved Riemannian metrics on M, which is the topological quotient of.the space of.all negatively curved metrics modulo the space of.self.dif.eomorphisms of.M that are homotopic to the identity.

关键词： space of.Riemannian metrics negative curvature complex hyperbolic space

Isometry Groups of.Some Dunwoody Manif.lds

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Algebra Colloquium 2016年第1期23卷 117-128页

作者： f. Spaggiari A.I. Telloni Dipartimento di Matematica Universit& di Modena e Reggio E. Via Campi 213/B 41100 Modena Italy

Dunwoody manif.lds are an interesting class of.closed connected orientable 3-manif.lds, which are def.ned by means of.Heegaard diagrams having a rotational symmetry. They are proved to be cyclic coverings of.lens spaces （possibly S3） branched over （1, 1）-knots. Here we study the Dunwoody manif.lds which are cyclic coverings of.the 3-sphere branched over two specif.ed f.milies of.Montesinos knots. Then we determine the Dunwoody parameters f.r such knots and the isometry groups f.r the considered manif.lds in the hyperbolic case. A list of.volumes f.r some hyperbolic Dunwoody manif.lds completes the paper.

关键词： Dunwoody manif.ld Montesinos knot branched covering isometry group

THEORY Of.BAINITIC TRANSf.RMATION: A MODEL WITH COUPLED f.RST-ORDER PHASE TRANSf.RMATIONS

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Acta Metallurgica Sinica(English Letters) 2000年第3期13卷 901-910页

作者： Liu, X. Zhong, f. Baoshan Iron and Steel Corp Shanghai China

The Ginzbury-Landau theory f.r bainitic transf.rmation was devised, which contains two f.rst-order phase transf.rmations, one being reconstructive represented by the dif.usional proeutectoidal precipitation of.f.rrite, and the other the displacive transf.rmation. It provides a coupled mechanism f.r the f.rmation of.bainite. With the numerical simulation results, a dif.usion-induced nucleation and a dif.usion-accompanied growth of.displacive transf.rmation were suggested. This theory can be helpf.l to over- throw the thermodynamic dif.iculty of.displacive transf.rmation above the Ms temperature, and also helpf.l to understand the Bs temperature, the partial supersaturation, the single variation of.bainitic carbides, and the incomplete-reaction phenomenon of.bainitic transf.rmation, etc..

关键词： Bainitic transf.rmations Computer simulation Crystalline materials f.nite dif.erence method Metallographic phases Nucleation Phase transitions Steel metallurgy Thermodynamics

Pico–nano bubble column f.otation using static mixer-venturi tube f.r Pittsburgh No.8 coal seam

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International Journal of.Mining Science and Technology 2015年第3期25卷 347-354页

作者： Peng f.licia f. Yu Xiong The Department of.Mining Engineering West Virginia University

The f.otation process is a particle-hydrophobic surf.ce-based separation technique. To improve the essential f.otation steps of.collision and attachment probabilities, and reduce the step of.detachment probabilities between air bubbles and hydrophobic particles, a selectively designed cavitation venturi tube combined with a static mixer can be used to generate very high numbers of.pico and nano bubbles in a f.otation column. f.lly embraced by those high numbers of.tiny bubbles, hydrophobic particles readily attract the tiny bubbles to their surf.ces. The results of.column f.otation of.Pittsburgh No. 8 seam coal are obtained in a 5.08 cm ID and 162 cm height f.otation column equipped with a static mixer and cavitation venturi tube, using kerosene as collector and MIBC as f.other. Design of.the experimental procedure is combined with a statistical two-stepwise analysis to determine the optimal operating conditions f.r maximum recovery at a specif.ed grade. The ef.ect of.independent variables on the responses has been explained. Combustible material recovery of.85–90% at clean coal product of.10–11% ash is obtained f.om f.ed of.29.6% ash, with a much-reduced amount of.f.other and collector than that used in conventional column f.otation. The column f.otation process utilizing pico and nano bubbles can also be extended to the lower limit and upper limit of.particle size ranges, minus 75 lm and 300–600 lm, respectively, f.r better recovery.

关键词： Pico-nano bubble generation Cavitation venturi tube f.ne coal f.otation Statistical analysis method

Simulation of.the f.ssion dynamics of.the excited compound nuclei ^206Po and ^168Yb produced in the reactions ^12C＋^194Pt and ^18O＋^150Sm

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Chinese Physics C 2017年第4期41卷 69-74页

作者： H. Eslamizadeh f. Bagheri Department of.Physics Persian Gulf University *** Bushehr Iran

A two-dimensional dynamical model based on the Langevin equation was used to study the f.ssion dynamics of.the compound nuclei ^206Po and ^168Yb produced in the reactions ^12C＋^194Pt and ^18O＋^150Sm,*** f.ssion cross section and average pre-scission neutron multiplicity were calculated f.r the compound nuclei ^206Po and ^168Yb,and results of.the calculations compared with the experimental *** elongation coordinate was used as the f.rst dimension and the projection of.the total spin of.the compound nucleus onto the symmetry axis,K,considered as the second dimension in the Langevin dynamical *** the two-dimensional calculations,a constant dissipation coef.icient of.K and a non-constant dissipation coef.icient have been used to reproduce the abovementioned experimental *** is shown that the two-dimensional Langevin equation can satisf.ctorily reproduce the f.ssion cross section and average pre-scission neutron multiplicity f.r the compound nuclei ^206Po and ^168Yb by using constant values of.the dissipation coef.icient of.K equal to γκ=0.18（MeV zs）^-1/2 and γκ= 0.20（MeV zs）^-1/2f.r the compound nuclei ^206Po and ^168Yb,respectively.

关键词： dissipation coef.icient Langevin model f.ssion cross section

Study of.the Reaction of.5-Aryl-7-hydrazino-2-phenylpyra- zolo[1,5-c]pyrimidines with 1,3-Dicarbonyl Compounds

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Chinese Journal of.Chemistry 2011年第11期29卷 2451-2460页

作者： Atta, Kamal f. M. Chemistry Department Faculty of Science Alexandria University lbrahimia P. O. Box 426 Alexandria 21321 Egypt

A novel synthetic method f.r the preparation of.5-aryl-7-（3,5-dimethyl-lH-pyrazol-l-yl）-2-phenylpyra- zolo[1,5-c]-pyrimidines and 1-（5-aryl-2-phenylpyrazolo[1,5-c]pyrimidin-7-yl）-3-methyl-lH-pyrazol-5-ols is provided by condensative cyclization of.5-aryl-7-hydrazino-2-phenylpyrazolo[1,5-c]pyrimidines with 1,3-dicarbonyl compounds. The study of.the more reactive position f.r electrophilic substitusion reactions on such ring system was also achieved.

关键词： cyclization electrophilic substitution pyrazolylpyrazolopyrimidine IR NMR mass spectrometry