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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Environmental geology 36 (1998), S. 277-284 
    ISSN: 1432-0495
    Keywords: Key words Soil ; Trace element ; Alluvial plain ; China
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  A study investigating the contents of 13 trace elements and the correlations between these trace elements and soil parameters of the surface soils in the eastern alluvial plains of China is summarized and discussed in this paper. The results show that the contents of some elements studied differ from region to region. Close relations have been noted between all the trace element contents in the soils of the eastern alluvial plains and the relevant surface materials of erosion regions, which demonstrate the effects of parent materials, while climatic conditions and human interventions are also found to be important factors. Close relations were found between the transition elements of the Quaternary period and the chalcophile elements (except Cu). The chemical and geochemical properties of these elements are identified as beeing important inherent characteristics that affect the relations of these elements in the soils.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Environmental geology 39 (2000), S. 1334-1340 
    ISSN: 1432-0495
    Keywords: Keywords China ; Geochemistry ; River ; Sediment ; Trace metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  A total of 26 geographically and hydrologically diverse sediment samples were collected from 12 major rivers in eastern China. The 〈63-μm fraction of the sediments was analysed for both total concentrations of Cu, Zn, Pb and Cd, and their associations with various geochemical phases. The geographical variations of sediment-bound trace metals can be related to the bedrock types and weathering processes in the corresponding river basins. The rivers in southern China had notably higher concentrations of trace metals in sediments because of abundant non-ferrous mineral deposits and stronger weathering process in the region. A large proportion of trace metals in these sediments was associated with iron and manganese oxides and organic matter. Relative low levels of trace metals were found in river sediments in northern China, and a significant proportion of the metals was bound to organic matter, carbonates, and the residual fraction. The sediments in the Yellow River, originating from special loess, had the lowest concentrations of trace metals. Most of the trace metals were associated with the carbonates and residual phases.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 24 (1975), S. 401-406 
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 53 (1980), S. 235-236 
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 52 (1991), S. 151-154 
    ISSN: 1432-0630
    Keywords: 66.30 ; 81.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The annealing behaviour of the Cu/Mo/Au metallization system is investigated. Backscattering spectrometry reveals a rapid diffusion of Cu and Au across the Mo film and the formation of AuCu after annealing at 600°C for 30 min in vacuum, but only when no impurity is detected in the as-deposited polycrystalline Mo layer. The Au-Cu interaction is impeded when 5.5 at% of oxygen is introduced in the as-deposited Mo layer. The thin film microstructures are analyzed using X-ray diffraction and transmission electron microscopy. The thermal stability difference between the samples with a pure Mo layer and a contaminated Mo layer is discussed in terms of fast diffusion process inhibited by a grain boundary decoration with oxygen atoms.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 40 (1991), S. S11 
    ISSN: 1432-1041
    Keywords: HMGCoA reductase in inhibitors ; cholesterol-lowering agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Lovastatin and simvastatin are potent competitive inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase. Key inhibit the synthesis of cholesterol in cultured HepG23 cells, rat hepatocytes and in rats. The primary target organ of cholesterol synthesis inhibition by lovastatin and simvastatin is the liver. Lovastating and simvastatin lower levels of plasma cholesterol in rats, dogs and rabbits by inhibition the endogenous cholesterol synthesis and induction of LDL receptor in the liver.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Computational mechanics 25 (2000), S. 157-168 
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  In this paper, a continuum-based shape design sensitivity formulation for a frictional contact problem with a rigid body is proposed using a meshless method. The contact condition is imposed using the penalty method that regularizes the solution of variational inequality. The shape dependency of the contact variational form with respect to the design velocity field is obtained. The dependency of the response with respect to the shape of the rigid body is also considered. It is shown that the sensitivity equation needs to be solved at the final converged load step for the frictionless contact problem, whereas for the frictional contact case the sensitivity solution is needed at the converged configuration of each load step because the sensitivity of the current load step depends on that of the previous load step. The continuum-based contact formulation and consistent linearization is critical for accurate shape design sensitivity results. The accuracy of the proposed method is compared with the finite difference result and excellent agreement is obtained for a door seal contact example. A design optimization problem is formulated and solved to reduce the contact gap opening successfully in a demonstration of the proposed method.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  Two major difficulties are encountered in the meshfree solution of incompressible boundary value problems. The first is due to the employment of higher-order quadrature rules that leads to an over-constrained discrete system in incompressible problems. The second is associated with the treatment of essential boundary conditions and contact conditions owing to the loss of Kronecker delta properties in the meshfree shape functions. This paper discusses some recent enhancements in meshfree methods for incompressible boundary value problems, carries out numerical convergence analysis, and compares accuracy and efficiency improvement of these methods. Presented methods are a pressure projection method to remedy the over-constrained discrete system, and a mixed transformation method and a boundary singular kernel method for imposition of essential boundary conditions and contact constraints. Several linear and nonlinear problems were analyzed to demonstrate the effectiveness of the new approaches.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Computational mechanics 19 (1997), S. 211-227 
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  A nonlinear formulation of the Reproducing Kernel Particle Method (RKPM) is presented for the large deformation analysis of rubber materials which are considered to be hyperelastic and nearly incompressible. In this approach, the global nodal shape functions derived on␣the basis of RKPM are employed in the Galerkin approximation of the variational equation to formulate the discrete equations of a boundary-value hyperelasticity problem. Existence of a solution in RKPM discretized hyperelasticity problem is discussed. A Lagrange multiplier method and a direct transformation method are presented to impose essential boundary conditions. The characteristics of material and spatial kernel functions are discussed. In the present work, the use of a material kernel function assures reproducing kernel stability under large deformation. Several of numerical examples are presented to study the characteristics of RKPM shape functions and to demonstrate the effectiveness of this method in large deformation analysis. Since the current approach employs global shape functions, the method demonstrates a superior performance to the conventional finite element methods in dealing with large material distortions.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    The international journal of advanced manufacturing technology 12 (1996), S. 266-275 
    ISSN: 1433-3015
    Keywords: Accuracy ; CNC machine tools ; Error compensation ; Thermal error modelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A modelling strategy for the prediction of both the scalar and the position-dependent thermal error components is presented. Two types of empirical modelling method based on the multiple regression analysis (MRA) and the artificial neural network (ANN) have been proposed for the real-time prediction of thermal errors with multiple temperature measurements. Both approaches have a systematic and computerised algorithm to search automatically for the nonlinear and interaction terms between different temperature variables. The experimental results on a machining centre show that both the MRA and the ANN can accurately predict the time-variant thermal error components under different spindle speeds and temperature fields. The accuracy of a horizontal machining centre can be improved through experiment by a factor of ten and the errors of a cut aluminium workpiece owing to thermal distortion have been reduced from 92.4 µm to 7.2 µm in the lateral direction. The depth difference due to the spindle thermal growth has been reduced from 196 µm to 8 µm.
    Type of Medium: Electronic Resource
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