Radial mixing and segregation of granular bed bi-dispersed both in particle size and density within horizontal rotating drum

Taking simultaneous variations in both particle volume and density into account, the radial mixing and segregation of binary granular bed in a rotating drum half loaded were investigated by a 3D discrete element method. Then, based on the competition theory of condensation and percolation, radial segregation due to differences in particle volume and/or density was analyzed. The results show that if either percolation effect induced by volume difference or condensation effect induced by density difference dominates in the active layer of moving bed, separation will occur. Controlling the volume ratio or density ratio of the two types of particles can achieve an equilibrium state between percolation and condensation, and then homogenous mixture can be obtained. When the percolation balances with the condensation, the relationship between volume ratioand density ratiopresents nearly a power function. Scaling up a rotating drum will not affect the mixing degree of the granular bed so long as the volume ratio and density ratio are predefined.

Removal of chromium(Ⅲ) from aqueous waste solution by predispersed solvent extraction

The extraction experiments of chromium（W） from aqueous waste solution by predispersed solvent extraction （PDSE） process with extractant （HEHPEHE） and its mixture, including acidic extractant （D2EHPA）, alkaline extractant （TOA） and neutral extractant （TBP） were carried out respectively. It is found that the extractant HEHPEHE exhibited high extraction selectivity to chromium（III） from aqueous waste solution. The colloidal liquid aphrons （CLAs） were successfully generated using kerosene as a solvent, HEHPEHE as an extractant, sodium dodecyl benzene sulphate （SDBS） as a surfactant in aqueous phase and polyoxyethylene sorbitol anhydride monolaurate （Tween-20） in oil phase. To study the extraction efficiency and advantages of the PDSE process in the removal of chromium（III）, the effects of major factors, such as initial chromium（III） concentration, volume of colloidal gas aphrons （CGAs）, HEHPEHE volume fraction, phase ratio （solvent phase to water phase）, mass fraction of dodecyl trimethylammonium bromide （HTAB）, mass fraction of SDBS, mass fraction of Tween-20 and initial pH of aqueous waste solution were also investigated and the appropriate process conditions were obtained. Under the appropriate conditions, the extraction efficiency of chromium（III） above 99.9 % can be achieved and the treated aqueous waste solution can be discharged directly without polluting the environment.

Numerical analysis of multicomponent responses of surface-hole transient electromagnetic method

We calculate the multicomponent responses of surface-hole transient electromagnetic method. The methods and models are unsuitable as geoelectric models of conductive surrounding rocks because they are based on regular local targets. We also propose a calculation and analysis scheme based on numerical simulations of the subsurface transient electromagnetic fields. In the modeling of the electromagnetic fields, the forward modeling simulations are performed by using the finite-difference time-domain method and the discrete image method, which combines the Gaver–Stehfest inverse Laplace transform with the Prony method to solve the initial electromagnetic fields. The precision in the iterative computations is ensured by using the transmission boundary conditions. For the response analysis, we customize geoelectric models consisting of near-borehole targets and conductive wall rocks and implement forward modeling simulations. The observed electric fields are converted into induced electromotive force responses using multicomponent observation devices. By comparing the transient electric fields and multicomponent responses under different conditions, we suggest that the multicomponent-induced electromotive force responses are related to the horizontal and vertical gradient variations of the transient electric field at different times. The characteristics of the response are determined by the varying the subsurface transient electromagnetic fields, i.e., diffusion, attenuation and distortion, under different conditions as well as the electromagnetic fields at the observation positions. The calculation and analysis scheme of the response consider the surrounding rocks and the anomalous field of the local targets. It therefore can account for the geological data better than conventional transient field response analysis of local targets.

WEIGHTED LEAST SQUARE METHOD FOR S-N CURVE FITTING

An S-N curve fitting approach is proposed based on the weighted least square method, and the weights are inversely proportional to the length of mean confidence intervals of experimental data sets. The assumption coincides with the physical characteristics of the fatigue life scatter. Two examples demonstrate the method. It is shown that the method has better accuracy and reasonableness compared with the usual least square method.

COMPUTER VISUALIZATION OF ELECTROMAGNETIC WAVE INTERACTION WITH STRUCTURES

In this paper, a computer visualization approach is proposed for electromagnetic wave interaction with structures by mains of finite difference-time doain method (F-D) and computer graphics. By visualization of FDTD, Phenomena such as wave propagation, penetration through structures, renection and absorption by structures are observed. Visualization of electromagnetic wave interactions with two wing-shaped structures is demonstrated. These examples indicate that the approach describe in the paper offers an effective way for investigating electromagnetic wave phenomena and is helpful to the engineers in controlling radar signature of the targets.

运用《九章算术》的算法破解分数除法教学之难题

分数除法的教学是一个公认的难题。运用刘徽所记载的“散分法”和“颠倒法”两种运算方法,能成功破解分数除法教学的难题。“散分法”与整数除法一脉相承,运用它可合理地解析分数除法的意义和算理;散分的过程和结果可用分数乘法进行表征,散分法就转化成了颠倒法;颠倒法的运算过程比散分法更为简便,颠倒法成为了分数除法的普适性计算法则。

Surface edge element method for 3-D electromagnetic computation

A surface edge element method is proposed and implemented in the study ofelectromagnetic scattering fields of general targets. The basis functions for surfaces of arbitraryshape are derived according to the geometrical properties of each triangular patch. The proposedbasis functions are 3-D linear functions and the tangential components of the vectors are continuousas the traditional edge element method. Combined field integral equations (CFIE) that include bothelectrical field and magnetic field integral equations are used to model the electromagneticscattering of general dielectric targets. Special treatment for singularity is presented to enhancethe quality of numerical solutions. The proposed method is used to compute the scattering fieldsfrom various targets. Numerical results obtained by the proposed method are validated by resultsfrom other numerical methods.

Preparation and in vitro Studies of Stealth PEGylated PLGA Nanoparticles as Carriers for Arsenic Trioxide

The aim of this study was to prepare arsenic trioxide （ATO）-loaded stealth PEGylated PLGA nanoparticles （PEG-PLGA-NPs） and to assess the merits of PEG-PLGA-NPs as drug carriers for ATO delivery. PEG-PLGA copolymer was synthesized with methoxypolyethyleneglycol （Mw=5000）, D, L-lactide, and glycolide by the ring-opening polymerization method. Amorphous ATO was transformed into cubic crystal form to increase its solu-bility in the organic solvent. ATO-loaded PEG-PLGA-NPs were prepared by the modified spontaneous emulsification solvent diffusion （SESD） method, and the main experimental factors influencing the characteristics of nanopar- ticles were investigated, to optimize the preparation. To confirm the escape of PEG-PLGA-NPs from phagocytosis by phagocytes, PEG-PLGA-NPs labeled rhodamine B uptake by murine peritoneal macrophages （MPM） were analyzed by flow cytometry. The results showed that the physicochemical characteristics of PEG-PLGA-NPs were affected by the type and concentration of the emulsifiers, polymer concentration, and drug concentration. ATO-loaded PEG-PLGA-NPs, with particle size of 120.8nm, zeta potential of-10.73mV, encapsulation efficiency of 73.6%, and drug loading of 1.36%, were prepared under optimal conditions. The images of transmission electron micros-copy （TEM） indicated that the optimized nanoparticles were near spherical and without aggregation or adhesion. The release experiments in vitro showed the ATO release from PEG-PLGA-NPs exhibited consequently sustained release for more than 26d, which was in accordance with Higuchi equation. The uptake of PEG-PLGA-NPs by MPM was found to decrease markedly compared to PLGA-NPs. The experimental results showed that PEG-PLGA-NPs were potential nano drug delivery carriers for ATO.

Quadrature Method of Moments for Nanoparticle Coagulation and Diffusion in the Planar Impinging Jet Flow

A computational model combining large .eddy simulation with quadrature moment method was em-ployed to study nanoparticle evolution in a confined impinging jet. The investigated particle size is limited in the transient regime, and the particle collision kernel was obtained by using the theory of flux matching. The simulation was validated by comparing it with the experimental results. The numerical results show coherent structure acts to dominate particle number intensity, size and polydispersity distributions, and it also induce particle-laden iet to be diluted by .the ambient.The evolution of particle dynarnics in.the impinging jet flow are strongly related to the Rey-nolds number and nozzle-to-plate distance, and their relationships were analyzed.

Kinematic analysis of geosynthetics-reinforced steep slopes with curved sloping surfaces and under earthquake regions

A procedure of kinematic analysis is presented in this study to assess the reinforcement force of geosynthetics required under seismic loadings, particularly for steep slopes which are hardly able to maintain its stability. Note that curved sloping surfaces widely exist in natural slopes, but existing literatures were mainly focusing on a planar surface in theoretical derivation, due to complicated calculations. Moreover, the non-uniform soil properties cannot be accounted for in conventional upper bound analysis. Pseudo-dynamic approach is used to represent horizontal and vertical accelerations which vary with time and space. In an effort to resolve the above problems, the discretization technique is developed to generate a discretized failure mechanism, decomposing the whole failure block into various components. An elementary analysis permits calculations of rates of work done by external and internal forces. Finally, the upper bound solution of the required reinforcement force is formulated based on the work rate-based balance equation. A parametric study is carried out to give insights on the implication of influential factors on the performance of geosynthetic-reinforced steep slopes.

Fractal Dromion,Fractal Lump,and Multiple peakon Excitations in a New （2＋1）—Dimensional Long Dispersive Wave SYstem

By means of variable separation approach, quite a general excitation of the new (2 + 1)-dimensional long dispersive wave system: is derived. Some types of the usual localized excitations such as dromions, lumps, rings, and oscillating soliton excitations can be easily constructed by selecting the arbitrary functions appropriately. Besides these usual localized structures, some new localized excitations like fractal-dromion, fractal-lump, and multi-peakon excitations of this new system are found by selecting appropriate functions.

Continuum and Discrete Element Coupling Approach to Analyzing Seismic Responses of a Slope Covered by Deposits

Numerical analyses of earthquake effects on the deformation, stability, and load transfer of a slope covered by deposits are traditionally based on the assumption that the slope is a continuum. It would be problematic, however, to extend these approaches to the simulation of the slide, collapse and disintegration of the deposits under seismic loading. Contrary to this, a discrete element method （DEM） provides a means to consider large displacement and rotation of the non-continuum. To take the advantages of both methods of continuum and non- continuum analyses, seismic responses of a slope covered by deposits are studied by coupling a twodimensional （a-D） finite difference method and a 2-D DEM, with the bedrock being modelled by the finite difference grids and the deposits being represented by disks. A smooth transition across the boundaries of the continuous/discontinuous domains is obtained by imposing the compatibility condition and equilibrium condition along their interfaces. In the course of computation, the same time-step value is chosen for both continuous and discontinuous domains. The free-field boundaries are adopted for lateral grids of bedrock domain to eliminate the radiation damping effect. When the static equilibrium under gravity load is obtained, dynamic calculation begins under excitation of the seismic wave input from the continuum model bottom. In this way, responses to the earthquake of a slope covered by deposits are analyzed dynamically. Combined with field monitoring data, deformation and stability of the slope are discussed. The effects of the relevant parameters of spectrum characteristic, duration, andpeak acceleration of seismic waves are further investigated and explained from the simulations.

Influences of nonassociated flow rules on three-dimensional seismic stability of loaded slopes

The influences of soil dilatancy angle on three-dimensional （3D） seismic stability of locally-loaded slopes in nonassociated flow rule materials were investigated using a new rotational collapse mechanism and quasi-static coefficient concept. Extended Bishop method and Boussinesq theorem were employed to establish the stress distribution along the rupture surfaces that are required to obtain the rate of internal energy dissipation for the nonassociated flow rule materials in rotational collapse mechanisms. Good agreement was observed by comparing the current results with those obtained using the translational or rotational mechanisms and numerical finite difference method. The results indicate that the seismic stability of slopes reduces by decreasing the dilatancy angle for nonassociated flow rule materials. The amount of the mentioned decrease is more significant in the case of mild slopes in frictional soils. A nearly infinite slope under local loading, whether its critical failure surface is 2D or 3D, not only depends on the magnitude of the external load, but also depends on the dilataney angle of soil and the coefficient of seismic load.

Interaction of Puerarin with Phospholipid in Solid Dispersion

Aim To study the interaction of puerarin (PU) with phospholipid (PL) in soliddispersion. Methods PU/PL solid dispersion was prepared with solvent evaporation and theinteraction between PU and PL was studied by analysis of their ultraviolet spectra, infraredspectra, ~1H NMR spectra and thin layer chromatogram. Results In chloroform the maximum absorptionpeak of PU in PU/PL mixture was located at 243 nm, but 251 nm for that of PU in solid dispersion.However in methanol, QU in mixture or solid dispersion had the same maximum absorption peak locationin ultraviolet spectra. Compared with the infrared spectra of mixture, that of solid dispersionshowed the specific absorption peak location of benzene ring framework in PU molecule was markedlychanged, the stretching vibration peak of P= O in PL molecule was shifted to high wavenumbers andthe stretching vibration peak of C = C in PL molecule was disappeared. In ~1H NMR spectra, most ofthe signals from PU in solid dispersion were weaken markedly or disappeared and the signals from thepolar part of PL molecule were significantly changed. PU and PL in solid dispersion could beseparated on silica gel plate with the mixed solvent of chloroform, methanol and water (65:25:5) orethyl acetate and methanol (10:1) . Conclusion In solid dispersion the benzene ring framework of PUmolecule could act with the polar part and unsaturated part of PL molecule through charges transfer,and the interacted part could be surrounded by fat chains of PL molecule.

Clinical Experience in Multiple Needling Therapy

The multiple needling therapy refers to the techniques used in acupuncture treatment with multineedles in multi-directions. But, it does not mean that more insertions with more needles would bring about better therapeutic effects.

Dispersion penalty analysis gor VSR-1 optical links

This paper presents an approach to calculate dispersion penalty for VSR-1 optical links.Based on parameters of a specific VSR-1 link,dispersion penalties are computed for various modal dispersion bandwidths respectively.The worst-case eye closure is expressed numerically by using the signal waveform at time 0,and the signal waveform is obtained in frequency domain through FFT algorithm.By this approach,the dispersion penalty is determined by the shape of transfer functions of the various components in the links.To simplify the derivation of multimode fiber link transfer function,a Gaussian form of normalized impulse response is used.This calculation approach can be used to estimate the worst-case dispersion penalty of VSR-1 links in the link budget analysis.

AN ESTIMATION OF FUZZY RELIABILITY OF DISTINCT ELEMENT METHOD IN PREDICTION OF SURFACE SUBSIDENCE DUE TO COAL MINING

The quantitative evaluation of errors involved in a particular numerical modelling is of prime importance for the effectiveness and reliability of the method. Errors in Distinct Element Modelling are generated mainly through three resources as simplification of physical model, determination of parameters and boundary conditions. A measure of errors which represent the degree of numerical solution 'close to true value' is proposed through fuzzy probability in this paper. The main objective of this paper is to estimate the reliability of Distinct Element Method in rock engineering practice by varying the parameters and boundary conditions. The accumulation laws of standard errors induced by improper determination of parameters and boundary conditions are discussed in delails. Furthermore, numerical experiments are given to illustrate the estimation of fuzzy reliability. Example shows that fuzzy reliability falls between 75%-98% when the relative standard errors of input data is under 10 %.

A NEW PUBLIC-KEY ENCRYPTION SCHEME BASED ON LUCAS SEQUENCE

Investigated the properties of LUCas sequence(LUC), the paper proposed a new variant of (probabilistic) public-key encryption scheme. Security analysis of the proposed encryption schemes shows that its one-wayness is equivalent to partial LUC discrete logarithm problem in ZN, and for the proposed probabilistic encryption scheme, its semantic security is equivalent to decisional LUC Diffie-Hellman problem in ZN. At last, the efficiency of the proposed schemes is briefly analyzed.

A RP-HPLC method for determination of paclitaxel in its solid dispersion

Aim To develop and validate a RP-HPLC method for the analysis of paclitaxel in a solid dispersion. Methods Paclitaxel and the internal standard norethisterone were separated using a Phenomenex ODS 3 column and monitored at a wavelength at 227 nm. The isocratic mobile phase consisting of methanol-acetonitrile-water （40：30：30, V/V） was pumped at a flow-rate of 1.0 mL·min^-1. The dissolution studies were performed according to published studies. Results Under these chromatographic conditions, the calibration curve was linear in the range of 4-40 μg·mL ^-1 with the correlation coefficient of 0.9999. The mean recovery was 98.42 % （RSD = 1.19 %）. At the 60 min time point, the dissolution of paclitaxel from the solid dispersion was nearly 100 %, however, the original form of paclitaxel was about 30 %. Conclusion The method was proven to be specific, accurate and precise for determining the dissolution of paclitaxel from solid dispersion.

HIGH-ORDER NYSTRM METHOD FOR THE EFIE OF EM SCATTERING PROBLEMS

Nystrm method is a new method for solving electromagnetic scattering problems. This paper gives the detailed description on high-order Nystrm method used for the electric field integral equation of electromagnetic scattering problems. The numerical solutions of two examples are correct compared with Method Of Moment(MOM).