CPTU试验在土体动力学参数计算中的应用研究

为探讨孔压静力触探(CPTU)数据能否在土体动力学参数计算中进行应用,结合港珠澳大桥补充勘察项目CPTU及波速测试资料,利用SPSS和OriginPro软件对比分析前人研究成果,提出了更适合于计算研究区波速(Vp、Vs)的经验拟合公式,公式考虑了深度影响,计算结果优于前人经验公式,尤其是当土层埋深大于30m时。基于此,对CPTU数据在土体动力学参数Ed、Gd及μd计算方面进行了对比分析研究,提出了研究区土体动力学参数计算公式,公式计算偏差均在可接受范围之内。同时发现土层深度及修正锥尖阻力的负指数形式在拟合土层纵、横波速Vp、Vs时具有重要意义。

克拉霉素胶囊人体生物等效性试验

本试验对12名男性健康自愿受试者口服四川抗菌素工业研究所及制药厂研制提供的克拉霉素胶囊和市售进口克拉霉素片的血药浓度和药代动力学参数进行了比较。血药浓度采用生物效价法测定,用3P87和NDST程序,按统计矩进行药代动力学参数计算和配对t检验分析。

The Calculation of Parameters for DNA Kinetic Structure Based on Monte-Carlo Multiple Integrals

Based on protein-DNA complex crystal structural data in up-to-date Nucleic Acid Database,the related parameters of DNA Kinetic Structure were investigated by Monte-Carlo Multiple Integrals on the base of modified DNA structure statistical mechanical model,and time complexity and precision were analyzed on the calculated results.

Effects of expanding zone parameters of vacuum dust suction mouth on flow simulation results

Based on the parametric analysis of the expanding zone of the vacuum dust suction mouth,the flow in the vacuum dust suction mouth was simulated by computational fluid dynamics(CFD)software,Fluent.The effects of the expanding zone parameters on flow simulation were analyzed.The results show that simulation effects depend on threshold values of the expanding zone parameters of the dust suction mouth,and the threshold values of the expanding zone can be obtained according to the different structures of the vacuum dust suction mouth and be selected as the geometric parameters in calculating,and also corners of the expanding zone make unobvious difference in calculation accuracy and in computational efficiency compared with no corner.The simulation results provide practical guidance to the flow simulation on the dust suction mouth.

Numerical simulation of effect of bionic V-riblet non-smooth surface on tire anti-hydroplaning

Inspired by the idea that bionic non-smooth surfaces(BNSS) can reduce fluid adhesion and resistance, and the effect of bionic V-riblet non-smooth structure arranged in tire tread pattern grooves surface on anti-hydroplaning performance was investigated by using computational fluid dynamics(CFD). The physical model of the object(model of V-riblet surface distribution, hydroplaning model) and SST k-ω turbulence model were established for numerical analysis of tire hydroplaning. With the help of a orthogonal table L16(45), the parameters of V-riblet structure design compared to the smooth structure were analyzed, and obtained the priority level of the experimental factors as well as the best combination within the scope of the experiment. The simulation results show that V-riblet structure can reduce water flow resistance by disturbing the eddy movement in boundary layers. Then, the preferred type of V-riblet non-smooth structure was arranged on the bottom of tire grooves for hydroplaning performance analysis. The results show that bionic V-riblet non-smooth structure can effectively increase hydroplaning velocity and improve tire anti-hydroplaning performance. Bionic design of tire tread pattern grooves is a good way to promote anti-hydroplaning performance without increasing additional groove space, so that tire grip performance and roll noise are avoided due to grooves space enlargement.

An improved self-adaptive membrane computing optimization algorithm and its applications in residue hydrogenating model parameter estimation

In order to solve the non-linear and high-dimensional optimization problems more effectively, an improved self-adaptive membrane computing(ISMC) optimization algorithm was proposed. The proposed ISMC algorithm applied improved self-adaptive crossover and mutation formulae that can provide appropriate crossover operator and mutation operator based on different functions of the objects and the number of iterations. The performance of ISMC was tested by the benchmark functions. The simulation results for residue hydrogenating kinetics model parameter estimation show that the proposed method is superior to the traditional intelligent algorithms in terms of convergence accuracy and stability in solving the complex parameter optimization problems.

Seeing permeability from images： fast prediction with convolutional neural networks

Fast prediction of permeability directly from images enabled by image recognition neural networks is a novel pore-scale modeling method that has a great potential. This article presents a framework that includes (1) generation of porous media samples,(2) computation of permeability via fluid dynamics simulations,(3) training of convolutional neural networks (CNN) with simulated data, and (4) validations against simulations. Comparison of machine learning results and the ground truths suggests excellent predictive performance across a wide range of porosities and pore geometries, especially for those with dilated pores. Owning to such heterogeneity, the permeability cannot be estimated using the conventional Kozeny–Carman approach. Computational time was reduced by several orders of magnitude compared to fluid dynamic simulations. We found that, by including physical parameters that are known to affect permeability into the neural network, the physics-informed CNN generated better results than regular CNN. However, improvements vary with implemented heterogeneity.

A study on the catalytic performance of carbide slag in transesterification and the calculation of kinetic parameters

The catalytic performance of carbide slag in transesterification is investigated and the reaction kinetic parameters are calculated. After being activated at 650℃, calcium compounds of carbonate and hydroxide in the carbide slag are mainly transformed into calcium oxide. The activated carbide slag utilized as the transesterification catalyst is characterized by X-ray diffraction （XRD）, attenuated total reflectance-Fourier transform infrared spectroscopy （ATR-FTIR）, nitrogen adsorption-desorption and the Hammett indicator method. Compared with the carbide slag activated at 700 and 800℃, the largest surface area of 22.63 m2g^-1, the smallest particle size of 265.12 nm and the highest catalytic efficiency of the carbide slag activated at 650℃ guarantee its capacity in catalyzing transesterification. Then, the influences of activated temperature （Ta）, molar ratio of methanol to oil （γ）, catalyst added amount （ζ）, reaction temperature （Tr） and reaction time （τ） on the catalytic performance are investi- gated. Under the optimal transesterification condition of Ta=650℃, γ=15, ζ=3%, Tr=60℃ and τ=-110 rain, the catalytic efficiency of 92.98% can be achieved. Finally, the kinetic parameters of transesterification catalyzed by the activated carbide slag are calculated, where activation energy （E） is 68.45 kJ mol^-1 and pre-exponential factor （k0） is 1.75×10^9 min^-1. The activated carbide slag shows better reused property than calcium hydroxide.