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Time-dependent Early-age Behaviors of Concrete under Restrained Condition

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Journal of Wuhan University of Technology(Materials Science) 2007年第2期22卷 350-353页

作者：马新伟 R d hooton h Lam School of Materials Science and Engineering Harbin Institute of Technology department of Civil Engineering University of Toronto

To investigate the early-age behaviors of concrete under a restrained condition, a set of apparatus was developed. In this way, the tensile creep and other early-age properties can be investigated in depth. By measuring the modulus of elasticity of concrete, synchronous shrinkage of concrete and steel rings and free shrinkage of concrete, the deformations of concrete ring can be quantified respectively. The experimental results show the tensile stress in concrete is time-dependent, and the stress at cracking is much lower than the tensile strength at that age; the tensile creep plays an important role in relaxing the tensile stress and postponing the cracking of concrete.

关键词： shrinkage restrained shrinkage elastic strain tensile creep time-dependent behaviors

Evaluation of alternative conceptual models for groundwater modelling

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Geoscience Frontiers 2017年第3期8卷 437-443页

作者： Yangxiao Zhou h.M.P.S.d.herath UNESCO-IhE Institute for Water Education

This study evaluates the alternative conceptual models for groundwater modelling. A true model was created with a synthetic alluvial fan-plain hydrogeological framework. Various alternative conceptual models were evaluated for groundwater flow simulations. The first alternative model is a single aquifer layer model; the second alternative model is a 3-layer aquifer model; and the third model is a B-layer model consisting of 3 aquifers separated by 2 aquitards. All models could fit very well to the observa- tions with optimized values of hydraulic conductivities. however, the single aquifer layer model can only compute water balance components with good accuracy. The 3-layer aquifer model can be used for water balance computation and groundwater head simulation with small errors. The 5-layer model is capable of simulating water budget, groundwater head distribution and travel times with high accuracy. Multi- model analysis found only the 3rd alternative model superior.

关键词： Alternative conceptual modelsMulti-model analysisWater budgetTravel time

Conformable Fractional Nikiforov–Uvarov Method

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Communications in Theoretical Physics 2016年第7期65卷 12-18页

作者： h.Karayer d.demirhan F.Buyukkilic department of Physics Faculty of Science Ege University，35100 Bornova，Izmir，Turkey

We introduce conformable fractional Nikiforov–Uvarov(NU) method by means of conformable fractional derivative which is the most natural definition in non-integer calculus. Since, NU method gives exact eigenstate solutions of Schr¨odinger equation(SE) for certain potentials in quantum mechanics, this method is carried into the domain of fractional calculus to obtain the solutions of fractional SE. In order to demonstrate the applicability of the conformable fractional NU method, we solve fractional SE for harmonic oscillator potential, Woods–Saxon potential, and hulthen potential.

关键词： fractional calculus fractional differential equations conformable fractional derivative conformable fractional Nikiforov-Uvarov method

Natural Killer Cells:Biology and Clinical Use in Cancer Therapy

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Cellular & Molecular Immunology 2004年第1期1卷 12-21页

作者： William h.d.hallett William J.Murphy department of Microbiology and Immunology University of Nevada School of Medicine.University of Nevada.Reno.Reno.NV.USA.

Natural killer (NK) cells have the ability to mediate both bone marrow rejection and promote engraftment,as well as the ability to elicit potent anti-tumor *** the clinical results for these processes are still *** understanding of NK cell biology,from activating and inhibitory receptor functions to the role of NK cells in allogeneic transplantation,needs to be appreciated in order to draw out the clinical potential of NK *** of bone marrow cell (BMC) rejection are known to be dependant on inhibitory receptors specific for major histocompatibility complex (MhC) molecules and on activating receptors that have many potential *** modulation of activating and inhibitory receptors may hold the key to clinical success involving NK ***-clinical studies in mice have shown that different combinations of activating and inhibitory receptors on NK cells can reduce graft-versus-host disease (GVhd),promote engraftment,and provide superior graft-versus-tumor (GVT) *** clinical data have shown that the use of KIR-ligand incompatibility produces tremendous graft-versus-leukemia effect in patients with acute myeloid leukemia at high risk of *** review will attempt to be a synthesis of current knowledge concerning NK cells,their involvement in BMT,and their use as an immunotherapy for cancer and other hematologic *** & Molecular Immunology.2004;1(1):12-21.

关键词： NK cell BMT GVhd GVT

Impact of systems modelling on agronomic research and adoption of new practices in smallholder agriculture

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Journal of Integrative Agriculture 2015年第8期14卷 1478-1489页

作者： d J Connor h van Rees P S Carberry The University of Melbourne Crop Facts Mandurang South 3551 Australia Commonwealth Scientific and Industrial Research Organization

An analysis of the impact of simulation modelling in three diverse crop-livestock improvement projects in Agricultural Research for development（AR4d） reveals benefits across a range of aspects including identification of objectives, design and implementation of experimental programs, effectiveness of participatory research with smallholder farmers, implementation of system change and scaling-out of *** planning change, farmers must consider complex interactions within both biophysical and socioeconomic aspects of their crop and animal production *** this, whole-farm models that include household models of food, workload and financial requirements have the most utility and *** analysis also proposes improvements in design and implementation of AR4 d projects to improve the utility of simulation modelling for securing positive agronomic and livestock outcomes and lasting legacies.

关键词： agricultural systems animal production crop production modelling research for development

Experimental investigation of tool wear and chip formation in cryogenic machining of titanium alloys

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Advances in Manufacturing 2015年第4期3卷 292-299页

作者： d. Biermann h. Abrahams M. Metzger Institute of Machining Technology TU Dortmund University Baroper StraBe 303 44227 Dortmund Germany

Titanium alloys are one of the most important design materials for the aircraft industry. The high strength-to-density-ratio and the compatibility with carbon fibre reinforced plastic are the reasons for a raising application in this field. The outstanding properties lead to challenging machining processes. high strength and low heat conductivity affect high mechanical and thermal loads for the cutting edge. Thus, the machining process is characterized by a rapid development of tool wear even at low cutting parameter. To reach a sufficient productivity it is necessary to dissipate the resulting heat from the cutting edge by a coolant. Therefore the cryogenic machining of two different titanium alloys is investigated in this work. The results point out the different behavior of the machining processes under cryogenic conditions because of the reduced thermal load for the cutting tool. According to this investigation, the cryogenic cooling with COa enables an increase of the tool life in comparison to emulsion based cooling principles when machining the α＋β-titanium alloy Ti-6Al-4V. The machining process of the high strength titanium alloy Ti-6Al-2Sn-4Zr-6Mo requires an additional lubrication realized by a minimum quantity lubrication （MQL） with oil. This combined cool- ing leads to a smoother chip underside and to slender shear bands between the different chip segments.

关键词： Titanium alloys . Cryogenic cooling Machining . Tool wear - Chip formation

AN AdAPTIVE VERSION OF GLIMM'S SChEME

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Acta Mathematica Scientia 2010年第2期30卷 428-446页

作者： h.Kim M.Laforest d.Yoon department of Mathematics Korea University département de mathématiques et génie industriel cole Polytechnique de MontréalMontréalQuébec

This article describes a local error estimator for Glimm＇s scheme for hyperbolic systems of conservation laws and uses it to replace the usual random choice in Glimm＇s scheme by an optimal choice. As a by-product of the local error estimator, the procedure provides a global error estimator that is shown numerically to be a very accurate estimate of the error in L1 （R） for all times. Although there is partial mathematical evidence for the error estimator proposed, at this stage the error estimator must be considered ad- hoc. Nonetheless, the error estimator is simple to compute, relatively inexpensive, without adjustable parameters and at least as accurate as other existing error estimators. Numerical experiments in 1-d for Burgers＇ equation and for Euler＇s system are performed to measure the asymptotic accuracy of the resulting scheme and of the error estimator.

关键词： conservation laws finite difference methods adaptive error estimation aposteriori

Mechanical Property Prediction of Commercially Pure Titanium Welds with Artificial Neural Network

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Journal of Materials Science & Technology 2005年第3期21卷 403-407页

作者： YanhongWEI K.K.d.h.Bhadeshia T.Sourmail StateKeyLaboratoryofAdvancedWeldingProductionTechnology HarbinInstituteofTechnologyHarbin150001China departmentofMaterialsScienceandMetallurgy UniversityofCambridgeCambridgeCB23QZUK

Factors that affect weld mechanical properties of commercially pure titanium have been investigated using artificial neural networks. Input data were obtained from mechanical testing of single-pass, autogenous welds, and neural network models were used to predict the ultimate tensile strength, yield strength, elongation, reduction of area, Vickers hardness and Rockwell B hardness. The results show that both oxygen and nitrogen have the most significant effects on the strength while hydrogen has the least effect over the range investigated. Predictions of the mechanical properties are shown and agree well with those obtained using the 'oxygen equivalent' (OE) equations.

关键词： Commercially pure titanium Artificial neural networks Mechanical properties Weld

Solution of Spin and Pseudo-Spin Symmetric dirac Equation in (1＋1) Space-Time Using Tridiagonal Representation Approach

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Communications in Theoretical Physics 2018年第3期69卷 241-256页

作者： I.A.Assi A.d.Alhaidari h.Bahlouli department of Physics and Physical Oceanography Memorial University of Newfoundland St. John's NL A1B3XT Canada Saudi Center for Theoretical Physics P.O. Box 32741 Jeddah 21438 Saudi Arabia Physics department King Fahd University of Petroleum & Minerals Dhahran 31261 Saudi Arabia

The aim of this work is to find exact solutions of the dirac equation in(1+1) space-time beyond the already known *** consider exact spin(and pseudo-spin) symmetric dirac equations where the scalar potential is equal to plus(and minus) the vector *** also include pseudo-scalar potentials in the *** spinor wavefunction is written as a bounded sum in a complete set of square integrable basis,which is chosen such that the matrix representation of the dirac wave operator is tridiagonal and *** makes the matrix wave equation a symmetric three-term recursion relation for the expansion coefficients of the *** solve the recursion relation exactly in terms of orthogonal polynomials and obtain the state functions and corresponding relativistic energy spectrum and phase shift.

关键词： dirac equation spin and pseudo-spin tridiagonal representations recursion relation orthogonal polynomials