An investigation for structure transformation in electric pulse modified liquid aluminum

The electric pulse (EP) modification of liquid metal is a novel method for grain refinement. In this work, the structure tests of EP-modified liquid aluminum were conducted and investigated using high-temperature X-ray diffractometer by virtue of the outstanding structural heredity of EP-modified liquid aluminum. The results show that the EP-modified liquid structure tends to be slack and unordered with increasing temperature similar to that of the unmodified. Nevertheless, the quantitative characterization denoted by the liquid structural parameters exhibits its discrepancy. At the modifying temperature of 750 °C, the order of degree of EP-modified liquid aluminum is remarkably strengthened and the value of average atomic number per cluster changes from 119 (no EP) up to 174 (EP) by an increase of 46%. These tests experimentally testified Wang's electric pulse modification (EPM) model that was built only by phenomenology, and hereby the mechanism of grain refinement resulting from EPM is further elucidated.     

Cross metathesis of butene-2 and ethene to propene over Mo/MCM-22-Al2O3 catalysts with different Al2O3 contents

A series of 3.0Mo/MCM-22-Al2O3 catalysts with γ-Al2O3 contents in the range of 0-100 wt% were prepared and applied in the metathesis reaction of ethene and butene-2. Addition of γ-Al2O3 did not affect the structure of MCM-22 zeolite as evidenced by XRD and N2 adsorption measurements. It was deduced from TPR experiments that γ-Al2O3 phase favored the formation of polymolybdate or multilayered Mo oxide, while more Al2(MoO4)3 species were generated over MCM-22 zeolites. Alumina content in the support was directly related to the metathesis activity of ethene and butene-2 to propene. Mo species with higher valence (Mo⁶⁺or Mo⁵⁺) contributed more to the excellent performance of catalyst than metallic Mo. The best catalyst activity and stability was obtained over 3.0Mo/(MCM-22-30%Al2O3) under the reaction condition of 1.0 MPa and 125 ℃ using N2 as the pretreatment gas.     

On Gliding Hump Properties of Matrix Domains

In this note, we establish several results concerning the gliding hump properties of matrix domains. In order to discuss F-WGHP, we introduce the UAK-property and find that this sort of property has close relationship with F-WGHP. In the course of discussing F-WGHP and WGHP of （C0）cn, we discuss the F-WGHP and WGHP of the almost-null sequence space f0.     

固体石蜡利多卡因碳糊电极电位法测定利多卡因

制备了一种以利多卡因与HgI₄^2-形成的缔合物为电活性物质的固体石蜡利多卡因碳糊电极,并对其性能做了测定。结果显示:电极对利多卡因有较好的能斯特响应。利多卡因的线性范围为5.0×10^-5～1.6×10^-2mol·L^-1,极差电位为29 mV/pc,测定下限为1.3×10^-5mol·L^-1。电极用于盐酸利多卡因注射液中利多卡因含量的测定,结果与药典法测定值相符。     

线性扫描伏安法测定氟罗沙星

应用线性扫描伏安法和循环伏安法研究氟罗沙星在玻碳电极上的电化学行为。在含有铜离子的pH 6.5的0.10mol.L-1磷酸盐缓冲溶液中,铜离子在玻碳电极上分别于-0.136V和-0.728V处形成两个还原峰,加入氟罗沙星后铜离子的还原峰电位不变但峰电流均降低。在优化的试验条件下,于-0.136V处的峰电流降低值Δip与氟罗沙星浓度在6.40×10-7～1.5×10-4 mol.L-1范围内呈线性关系,检出限为2.10×10-7 mol.L-1。方法用于氟罗沙星片剂中氟罗沙星含量的测定,回收率在96.8%～103.5%之间。     

基于观测器的一类模糊时滞系统的容错控制

针对一类带有传感器故障的模糊时滞系统,提出了一种实现对系统的状态和传感器故障估计的观测嚣设计方法.在此基础上,给出了模糊容错控制方法及保证模糊控制系统的渐近稳定充分条件.应用广义Lyapunov函数和线性矩阵不等式方法,证明了模糊闭环时滞系统的渐近稳定性.仿真结果进一步验证了所提出的方法和条件的有效性.     

3D nonlinear variable strain-rate-dependent-order fractional thermoviscoelastic dynamic stress investigation and vibration of thick transversely graded rotating annular plates/discs

In the present article, the idea of using the variable-order fractional-derivative thermoviscoelastic constitutive laws in dynamic stress and vibration analysis of the engineering structures, the required implementation backgrounds, and the relevant numerical solution procedures are investigated for the first time. In this regard, dynamic 3D stress and displacement fields and radial/transverse vibrations of transversely graded viscoelastic spinning thick plates/discs exposed to sudden thermoelastic loads are investigated. Instead of using the approximate plate theories, the exact thermoviscoelasticity theory is employed in the development of the governing equations. Since the variable fractional order is dependent on the localized deformation rates, the resulting thermoviscoelastic integro-differential equations are nonlinear. These equations are solved by utilizing a combination of the second-order backward/central/forward finite difference discretization of the spatial and time domains, numerical evaluation and updating of the Caputo-type fractional derivatives, updating the growing number of terms of the governing equations, and Picard's iterations. Various edge conditions are considered. Finally, comprehensive sensitivity analyses and various 3D plots are presented and discussed regarding the effects of the variable fractional order of the constitutive law, time variations of the nonuniformly distributed transverse loads, and edge conditions on the distributions and damping of the resulting displacement and stress components.     

Numerical analysis of bifurcation problem with corank-n

In this paper, numerical approximation of solution branches of bifurcation problem with corank-n is studied. This project is supported by the Natural Science Foundation of Liaoning Province     

同心球间旋转流动类Lorenz方程组的分歧问题

本文对同心球间旋转流动的Navier-Stokes方程谱展开后进行三模态截断,研究了所得到的类Lorenz型方程组的分歧问题.推导了同心球间旋转流动的Navier-Stokes方程的流函数-涡度形式,给出了静态奇异点的条件,并计算出解分支.