用于儿童斜视矫正的微结构压贴三棱镜

针对儿童斜视辅助治疗的色散问题,提出了利用微棱镜阵列组消除压贴三棱镜中的色散现象的设计方案。通过压贴三棱镜平移光线,用微棱镜阵列组进行色散补偿,设计了一个新颖的组合光学系统。阐述了微棱镜阵列组色散补偿的基本原理,并利用几何光学软件仿真了组合光学系统的色散、透过率等光学参数。点列图以及扩散函数图等仿真结果表明,微棱镜阵列对于减少压贴三棱镜的色散有较明显的效果。     

Isolation and characterization of Lactobacillus strains involved in koumiss fermentation

Koumiss is a slightly alcoholic fermented milk beverage, originally obtained by using natural mix starters (lactic acid bacteria and yeast). Seven Lactobacillus strains from lyophilized koumiss were isolated and identified as L. salivarius, L. buchneri and L. plantarum. The process of lactic acid fermentation caused by koumiss strains was faster (9–13 h) than that with other lactobacilli. The conversion ratio of glucose to lactic acid ranged from 47% to 79% and was strain dependent. All strains were resistant to low pH. Three of the strains isolated were viable during prolonged cold storage in fermented milk (3 weeks at 4°C).     

Tuneable Two-Pole One-Dielectric-Resonator Filter with Elliptic Characteristics

A frequency tuneable microwave filter based on a dual mode dielectric resonator has been developed. Tuning of the filter was realised by using metal plate located over the dielectric resonator and moved along the resonator axis by a piezoelectric bimorph. The main parameters of the filter were: central frequency in the middle of the range of tuning—2.35 GHz, bandwidth for 1dB level—～ 0.5%, range of tuning—～ 10%. The insertion losses in the whole tuning range were below ～ 1 dB.     

Sintering Behaviour of BaxSr1-xTiO3

This paper deals with the sintering behaviour of Barium Strontium Titanate (BST). Two methods were examined; method 1: BaTiO₃ + SrTiO₃ source powders; method 2: BaCO₃ + SrCO₃ + TiO₂ source powders. Commercially available 50 nm BST (x = 0.60) powder was used to investigate the effect of particle size on activation energy (E_a). Discs were sintered in a Netzsch 402C Dilatometer and E_a for the powders were obtained by applying the Arrhenius expression. The results indicate powders made from both methods display a varying trend in E_a over a range of x. The commercial powder yielded a higher E_a compared with powder made from method 1.     

Structural macromechanics approach in dynamics of fracture

Discrete features of the dynamics of fracture of solids are analyzed. The problem of modeling of some of the specific effects of brittle fracture in the high loading rate conditions is discussed. An approach based on the system of fixed material constants describing macro‐strength properties of the material is considered. New principles of material testing are analyzed. The corresponding incubation time criterion allows one to manage without the a priori given rate dependences of dynamic strength and fracture toughness. An application of the incubation time criterion to the problem of erosion is considered.     

微棱镜逆反射材料特性分析及制作

对微棱镜逆反射材料进行了理论研究和实验制作.理论分析了微棱镜单元内光线的逆反射特性,并研究了全反射条件对入射孔径角的限制以及阵列结构的逆反射率.提出了一种新的工艺方法,用于制作大尺寸的微棱镜模版.该方法将小尺寸镍模版利用类似"盖章"的方法在较大尺寸的聚碳酸酯基底上依次压制并使其紧密排列,然后再利用电铸的方法生长出大尺寸镍工作模版.最终得到了尺寸为500 mm×100 mm的模版.使用其制作的样片的逆反射系数最高大于750 cd/(1x·m2).