介绍两种数字-模拟混合式无笔记录仪

该文介绍了两种高品质的记录仪──XJRA－303数字－模拟混合式无笔记录仪和PHA／PHC型彩色喷墨式记录仪在结构原理和功能上的特点，以便于工程技术人员选择和应用。

Characterization on the hydrodynamics of a covering-plate Rushton impeller

A modified Rushton impeller with two circular covering-plates mounted on the upper and lower sides of the blades was designed.There are gaps between the plates and the blades.The turbulent hydrodynamics was analyzed by the computational fluid dynamics(CFD) method.Firstly,the reliability of the numerical model and simulation method was verified by comparing with the experimental results from literature.Subsequently,the power consumption,flow pattern,mean velocity and mixing time of the covering-plate Rushton impeller(RT-C) were studied and compared with the standard Rushton impeller(RT) operated under the same conditions.Results show that the power consumption can be decreased about 18%.Compared with the almost unchanged flow field in the lower stirred tank,the mean velocity was increased at the upper half of the stirred tank.And in the impeller region,the mean axial and radial velocities were increased,the mean tangential velocity was decreased.In addition,the average mixing time of RT-C was shortened about 4.14% than the counterpart of RT.The conclusions obtained here indicated that RT-C has a more effective mixing performance and it can be used as an alternative of RT in the process industries.

Numerical Simulation of Response of SRC Columns Subjected to Blast Loading

The dynamic characteristics and failure modes of steel reinforced concrete (SRC) columns subjected to blast loading are complicated because of the transient stress wave in the SRC columns and the interaction between steel and concrete. This paper presents a numerical simulation of the response of SRC columns subjected to blast loading using hydrocode LS-DYNA. In the numerical model, a sophisticate concrete material model (the Concrete Damage Model) is employed with consideration of the strain rate effect and the damage accumulation. An erosion technique is adopted to model the spalling process of concrete. The possible failure modes of SRC columns are evaluated. It is observed that the failure of SRC columns subjected to blast load can generally be classified into three modes, namely, a direct failure in concrete body due to the stress wave, a transverse shear failure near the support sections due to the high shear force, and a flexural failure pertaining to large local and global deformation of the reinforcing steel.

Mathematical model of convection diathermanous coefficient of refrigerator car

It is analyzed that the influence factors on temperature field of refrigerator car. The mathematical model of convection diathermanous coefficient has been put forward. It is considered in the model that the parameters of wind speed , car speed , temperature of car surface , temperature of surroundings , etc. If the boundary conditions and parameters used in calculation model of convection transmits heat coefficient are confinned as following： the cold plank car velocity Vis 120 km/h, and air temperature is 25 ℃, and the atmosphere press is 1013250 Pa, and wind velocity Viis 10 m/s, and the length of car bodywork Lis 5 m, and bodywork surface temperature is 25 ℃. The results were obtained by the model： when the wind velocity direction is the same as car velocity, the coefficient Kof convection transmits heat is 51.4（W· m^-2· K^-1 ）, and when the wind velocity direction is against the car velocity, K is 90.58 （W ·m^-2· K^-1）.

An intuitive general rank-based correlation coefficient

Correlation analysis is an effective mechanism for studying patterns in data and making predictions.Many interesting discoveries have been made by formulating correlations in seemingly unrelated data. We propose an algorithm to quantify the theory of correlations and to give an intuitive, more accurate correlation coefficient.We propose a predictive metric to calculate correlations between paired values, known as the general rank-based correlation coefficient. It fulfills the five basic criteria of a predictive metric： independence from sample size,value between-1 and 1, measuring the degree of monotonicity, insensitivity to outliers, and intuitive demonstration.Furthermore, the metric has been validated by performing experiments using a real-time dataset and random number simulations. Mathematical derivations of the proposed equations have also been provided. We have compared it to Spearman＇s rank correlation coefficient. The comparison results show that the proposed metric fares better than the existing metric on all the predictive metric criteria.

Numerical simulation of physiologically relevant pulsatile flow of blood with shear-rate-dependent viscosity in a stenosed blood vessel

Pulsatile flow of blood in a blood vessel having time-dependent shape （diameter） is inves-tigated numerically in order to understand some important physiological phenomena in arteries. A smooth axi-symmetric cosine shaped constriction is considered. To mimic the realistic situation as far as possible, viscosity of blood is taken to be non-uniform, a shear-thinning viscosity model is considered and a physiologically relevant pulsatile flow is introduced. Taking advantage of axi-symmetry in the proposed problem, the stream function-vorticity formulation is used to solve the governing equations for blood flow. Effect of different parameters associated with the problem on the flow pattern has been investigated and disparities from the Newtonian case are discussed in detail.

Singularly Perturbed Solution for Nonlinear Equations of Fourth Order with Two Parameters

A class of singularly perturbed boundary value problem for nonlinear equation of fourth order with two parameters is considered. Under suitable conditions, the existence and asymptotic behavior of solution for boundary value problem are studied using theory of differential inequalities.

Influence of mantle convection to the crustal movement pattern in the northeastern margin of the Tibetan Plateau based on numerical simulation

Based on the recent observations about the movement and rheological structure of the lithosphere and deformation pattern of the crust, we developed a three-dimensional finite element model for the northeastern margin of the Tibetan Plateau.The model considered the impacts of both external and internal conditions, including mantle convection, gravitational potential energy and block interactions. We compared the simulated surface movement rates to the observed GPS velocities, and the results revealed that crustal movement gradually decreased toward the edge of the plateau. The factors controlling this pattern are the interactions of adjacent blocks, gravitational potential energy of the plateau, and also mantle convection as well. Additionally,according to the observation that there was an apparent difference between the horizontal movement rate of the lithosphere and convective velocity of the underlying mantle, and also based on the results of seismic anisotropy studies that suggest different strengths and deformation regimes of the lithosphere in different tectonic blocks, we proposed that the impact of mantle convection on the lithosphere may have varied in space, and introduced a parameter named mantle convection intensity factor in numerical simulations. Our simulation results show consistent surface movement rates with GPS observations, which further supports the viewpoint of seismic anisotropy studies, i.e., the degree of coupling between the crust and mantle varies significantly among different blocks.

Bingham Flows in Periodic Domains of Infinite Length

The Bingham fluid model has been successfully used in modeling a large class of non-Newtonian fluids. In this paper, the authors extend to the case of Bingham fluids the results previously obtained by Chipot and Mardare, who studied the asymptotics of the Stokes flow in a cylindrical domain that becomes unbounded in one direction, and prove the convergence of the solution to the Bingham problem in a finite periodic domain, to the solution of the Bingham problem in the infinite periodic domain, as the length of the finite domain goes to infinity. As a consequence of this convergence, the existence of a solution to a Bingham problem in the infinite periodic domain is obtained, and the uniqueness of the velocity field for this problem is also shown. Finally, they show that the error in approximating the velocity field in the infinite domain with the velocity in a periodic domain of length 2l has a polynomial decay in , unlike in the Stokes case （see [Chipot, M. and Mardare, S., Asymptotic behaviour of the Stokes problem in cylinders becoming unbounded in one direction, Journal de Mathgmatiques Pures et Appliqudes, 90（2）, 2008, 133-159]） where it has an exponential decay. This is in itself an important result for the numerical simulations of non-Newtonian flows in long tubes.