Influence of microstructure of lactone‐based triblock copolymers on drug release behavior of their microspheres

The current work focuses on the influence of microstructure of different lactone‐based triblock copolymers on drug delivery, where the middle segment was δ‐valerolactone or ?‐caprolactone and the terminal segment was d ,l ‐lactide or <i>cis </i>‐lactide. Microspheres were fabricated from the triblocks using salicylic acid as the model drug. The microsphere formation and drug release were investigated by scanning electron microscopy, ultraviolet–visible spectroscopy, X‐ray diffraction, and thermogravimetry. The size of the microspheres ranged from 2 to 20 µm in diameter. The diffusion coefficient values showed that replacement of the middle segment, δ‐valerolactone with ?‐caprolactone, retarded the diffusion of the drug molecules. The diffusion coefficient was lowered when d ,l ‐lactide content was decreased in the triblock. Mathematical models were used to predict the drug release from the microspheres of different triblocks. The modeling study on drug release profiles revealed that the biodegradable nature of the triblock played a crucial role in determining the drug release kinetics. The diffusion and degradation reaction justified the drug release from microsphere. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , <i>134 </i>, 45284.     

轿车制动钳总成的缸孔与活塞间隙匹配设计

针对球磨铸铁件材料的制动钳总成在低纬度地区高温工作环境中的可靠性和综合性能进行优化设计,减小因环境温度变化大对制动性能影响,提高制动钳总成的综合性能和使用寿命。     

波动理论在强夯加固机理研究中的应用

介绍了强夯法加固地基的几个主要作用 ,基于波动理论推导了土层中的波动方程和超静孔压微分方程并得到通解。研究表明 ,强夯产生的震动作用使得土体的孔隙水压呈波动上升 ,砂土层液化的难易取决于埋深与地面加速度。并可据此方程推算强夯法加固地基中不同强夯击能的加固深度     

一种新的基于多尺度几何分析的图像融合方法

基于多尺度几何分析方法——非下采样轮廓波(Con tourlet)变换(NSCT)和Beamlet变 换,提出一种全新的医学图像融合方法。在进行NSCT分解后,在高频成分首先使用Beamlet 变换进行边缘检测, 然后根据聚类分割边缘密度的差值确定其系数的融合规则;对于低频成分,采用局部区域标 准方差系数的融合规则;经过 一致性校正后,通过对融合后的高频与低频子带系数进行逆NSCT得到重构图像。数值实验表 明,与传统的融合方法相 比较,本文方法能够有效减少噪声对融合图像的干扰,增强了融合的线性细节表达能力,提 高了信息量。     

卫星信号地面接收干扰的解决方案探讨

简要介绍了卫星信号地面接收受干扰时的解决思路,着重介绍了几种异地接收回传方案,给出了系统原理结构框图及该方案的优缺点.     

直流电阻箱检定装置测量不确定度的评定

重点论述了直流电阻箱检定装置的不确定度来源，并对此检定装置的不确定度进行了分析与计算。     

Impact of fluid path geometry and operating parameters on l/l-dispersion in interdigital micromixers

The dispersion of two immiscible fluids in interdigital micromixers was investigated using silicon oil/water and <em>n</em>-heptane/water as test systems. The experiments revealed the dependence of the average droplet size and size distribution on geometrical parameters of the micromixer and operating conditions. The mean droplet size was found to be correlated with total volume flow, volume flow ratio and corresponding pressure drop of the two liquids for a given micromixer geometry, which could be explained in light of the energy input. As a major focus, the effect of mixing chamber geometry and feeding system geometry was investigated with regard to droplet size distribution by systematically varying decisive dimensions in the mixer and by changing the feeding structure. It was shown that reducing the slit height and the number of feeding channels had a significant effect on droplet size distribution, leading to a smaller mean droplet size. Furthermore, the dispersion efficiency was also investigated by an extraction process.     

试论职工队伍技术素质下降原因及对策

21世纪世界经济的竞争是人才的竞争。而我国目前产业工人队伍的技术素质令人担忧，本文论述了职工队伍技术素质下降的原因及对应的解决办法。     

具有影像增强反射层的全彩色透反射型胆甾相液晶显示器

本文介绍了一种低功耗全彩透反射型液晶显示器。该液晶显示器利用高双折射率(Δn)胆甾相液晶(Ch-LC),并在透射区域的顶部设置了一块影像增强反射层(IER)。高双折射率(Δn)胆甾相液晶能够反射宽波段的光而显示白色图像。采用传统的彩色滤光膜方法就可以显示全彩色图像。此外,在透射区顶部的IER为透射光和反射光提供了相似的光路。在任何环境下,透射区与反射区总是显示相同的图像颜色,因而大大提高了全彩色透反射型胆甾相液晶显示器显示图像的质量。     

空调室内三维紊流流动与传热的数值模拟

采用三维紊流模型，应用有限容积法计算了室内空调的气固耦合传热问题，并对室内空调的气流组织形式，主要是对流速场，温度场进行了数值模拟计算，为空调室内的气流组织形式的优化设计及舒适性提供了研究依据。