破碎出矿巷道围岩变形机制数值模拟研究

研究了九顶山铜钼矿2 480 m水平201采场出矿巷道开挖后的二次应力分布及巷道变形机制。首先根据现场工程地质勘查和室内岩石力学试验对巷道围岩进行了岩石力学参数确定;在此基础上运用FLAC3D数值模拟软件研究了巷道开挖后的应力应变状态,分析了围岩变形机制。研究结果表明,围岩条件不同的出矿巷道其二次应力分布影响范围有所差异,但围岩主应力总体上表现为由巷道边墙中下部位的压应力集中带逐步过渡到拱顶、底板一定范围内的拉应力集中带。     

一维4H-碳化硅光栅红外光学特性及红外尺应用

从理论和实验上对极化材料4H-SiC一维光栅的光学特性进行了研究。发现该结构中存在四种光学模式:传播表面声子极化激元、偶极子天线、局域表面声子极化激元和准静态表面声子极化激元。进一步利用传播表面声子极化激元对于光栅结构参数的敏感性和原子层沉积技术生长介质材料,观察到了沉积材料厚度变化和传播表面声子极化激元的峰位偏移量呈现线性关系。该研究有助于新型微纳器件如纳米尺、传感器等的开发。     

Isolation, purification and ultrastructure of bacteriophages from natural mosquito breeding places in Egypt

Two bacteriophages were isolated from field collected samples representing two different mosquito breeding places. The phage AB-1 (isolated from Abheit village, Faiyoum Governorate "seepage water") and the phage GA-2 (isolated from El-Gabal El-Asfer Qualyobia Governorate "sewage drain water") were purified. Both bacteriophages were ultrastructurally described with respect to their morphology, dimensions, phases of bacterial attack and lysogeny. No major differences were observed between both isolated phages in relation to specificity, however; they were isolated from two different types of breeding places and two different geographic areas as well. This study may assume a wide host range of the isolated phages and reflect how bacterial insecticides used for mosquito larval control could be inhibited by such bacteriophage.     

Longitudinal Excitations in Triangular Lattice Antiferromagnets

We study the longitudinal excitations of quantum antiferromagnets on a triangular lattice by a recently proposed microscopic many-body approach based on magnon-density waves. We calculate the full longitudinal excitation spectra of the antiferromagnetic Heisenberg model for a general spin quantum number in the isotropic limit. Similar to the square lattice model, we find that, at the center of the first hexagonal Brillouin zone Γ (q=0) and at the magnetic ordering wavevectors ±[Q=(4π/3,0)], the excitation spectra become gapless in the thermodynamic limit, due to the slow, logarithmic divergence of the structure factor. However, these longitudinal modes on two-dimensional models may be considered as quasi-gapped, as any finite-size effect or small anisotropy will induce a large energy gap, when compared with the counterpart of the transverse spin-wave excitations. We also discuss a possible second longitudinal mode in the triangular lattice model due to the noncollinear nature of its magnetic order.     

基于FLAC~(3D)的采场顶板稳定性分析与支护设计

为了维护采场顶板稳定性,确保采场安全生产,在前期现场调查、原岩应力测定、确定室内岩石力学参数试验数据等基础上,采用FLAC3D方法对谦比希西矿体采空区稳定性进行模拟计算和支护设计。设计采用锚杆支护作为顶板稳定性控制措施,并采用工程类比法确定了锚杆的合理参数;对无支护和锚杆支护两种方案进行了分析研究,模拟结果表明选取树脂锚杆支护能够减小顶板压力,控制顶板位移变形和岩体冒落。后期的现场实际观测表明,用树脂锚杆支护顶板之后,顶板的竖向下沉量从未支护的88.68mm减小到29.24mm;顶板塑性区也明显减小。说明能够保证采场顶板的安全稳定。     

On the numerical solution of the model for HIV infection of CD4 T cells

In this article, a variational iteration method (VIM) is performed to give approximate and analytical solutions of nonlinear ordinary differential equation systems such as a model for HIV infection of CD4⁺ T cells. A modified VIM (MVIM), based on the use of Padé approximants is proposed. Some plots are presented to show the reliability and simplicity of the methods.     

Mechanical,Thermal, and Microstructure Analysis of Silk- and Cotton-Waste-Fiber-Reinforced High-Density Polyethylene Composites

In this study, composite structures were produced using HDPE polymer with silk and cotton waste as reinforcement fibers in different ratios. Cotton and silk wastes were mixed in the ratios of HDPE/silk or cotton waste 100%/0%, 97%/3%, and 94%/6%. This mixture was prepared with double-screwed extruder. The tests were carried out in terms of tensile strength, % elongation, yield strength, elasticity module, izod impact strength, melt flow index (MFI), heat deflection temperature (HDT), and vicat softening temperature. Materials' thermal transitions were determined with differential scanning calorimetric (DSC) and microstructure properties with scanning electron microscope (SEM).