A modern approach for controlled transdermal delivery of diflunisal: optimization and in vivo evaluation

The purpose of the present work was to elaborate an optimized transdermal therapeutic system for diflunisal. Selection of suitable ingredients was done via solubility and phase behavior studies. Composition of microemulsion (ME) systems consisting of butyl lactate, Brij^® 97, Transcutol^® and water was optimized using augmented simplex lattice mixture design. The independent variables selected were the percentages of butyl lactate, surfactant mixture and water. The dependent variables were refractive index, pH, conductivity, viscosity, drug solubility in the ME formulation and the ex vivo skin permeation flux. Mathematical equations and response surface plots were used to relate the dependent and independent variables. The statistical validity of the polynomials was established. Optimized formulation factors were selected by desirability approach. The optimized ME formulation was converted into gel using Carbomer^® 934. The microemulsion based gel (MBG) showed better spreadability and 5.07-fold increase in the transdermal flux than Carbomer^® 934 gel. The in vivo antihyperalgesia assay performed on mice showed significant reduction of the licking time in the treated group compared to the control group. This demonstrated the reliability of the simplex lattice statistical design for predicting optimum ME formulation. The developed MBG proved its in vivo efficiency for transdermal delivery of diflunisal.     

Self-assembly of rod-terminally tethered three-armed star-shaped coil block copolymer: Investigation of the presence of the branching in the coil to the self-assembled behavior

Self-assembled behavior of rod-terminally tethered three-armed star-shaped coil block copolymer melts was studied by applying self-consistent-field lattice techniques in three-dimensional (3D) space. Similar to rod-coil diblock copolymers, five morphologies were observed, i.e., lamellar, perforated lamellar, gyroidlike, cylindrical and sphericallike structures, while the distribution of the morphologies in the phase diagram was dramatically changed with respect to that of rod-coil diblock copolymers. The perforated lamella was replaced by the cylinder when f_rod = 0.45, and the lamella was replaced by the perforated lamella when f_rod = 0.5 when the arms A₁ and A₂ had an equal length and the volume fraction of A₃ arm was low enough. Simulations were also performed when the arms A₁ and A₂ had unequal lengths. These results demonstrate that simple branching in the coil induces interesting microphase transitions.     

一维光折变光子晶格的带结构研究

利用双光束干涉在光折变LiNbO_3晶体中写入折射率周期性排列的光子晶格,运用平面波展开法研究这种光折变光子晶格的带结构,并对比不同折射率对比度下的带结构情况。     

二维光折变缺陷光子晶格的制作

研究了一种制作缺陷光子晶格的新方法,即交叉相位法。利用此方法,成功地在(2+1)维12μm×12μm的光子晶格中构造了微米量级的线缺陷和点缺陷,验证了此方法在构造缺陷光子品格的可行性和优越性。     

清洁机器人全覆盖路径规划算法综述．

各种应用型移动机器人的设计是目前研究的焦点,它具有广阔的科研价值和市场前景,而路径规划技术是其中关键技术之一。本文系统总结了当前全覆盖路径规划算法的主要研究成果,并在覆盖效率、算法实现难易等指标方面进行比较剖析,探讨了各种算法的优势和不足。最后,提出进一步研究的方向。     

首都国际机场T3航站楼交通中心钢结构体系稳定分析

以首都国际机场交通运输中心(GTC)大跨箱型钢拱结构为工程背景,以单拱、组拱和整体屋盖钢拱结构为研究对象,采用非线性有限元法分析结构失稳问题。在多种不利荷载组合作用下,研究对应于GTC钢结构体系的理想结构整体稳定性能并得出结构特征屈曲系数的基础上,考虑几何非线性、材料非线性,按最不利原则施加初始几何缺陷,计算结构的非线性稳定屈曲系数,获得相应的折减系数,并讨论了双重非线性对结构整体稳定的影响。同时,数值分析了主拱拱脚处腹板的局部稳定问题,结果说明,在拱脚处需合理设置加劲肋板来避免腹板局部失稳。     

常规焦炉上的完全型煤炼焦

简单介绍了型煤炼焦技术在国内外的发展情况。分析了型煤炼焦的优点,包括提高了非主流炼焦煤种的利用量;在降低入炉煤水分的同时,缩短了炼焦周期,降低了焦粉产率。但型煤炼焦也存在诸多问题,主要包括炉型小且适应性差,炼焦过程中对环境的污染严重,产出的炼焦产品质量不稳定。为了解决上述问题,研究了常规焦炉上的完全型煤炼焦技术。介绍了该工艺的流程,重点分析了其经济意义与技术可行性。结果表明:完全型煤炼焦可以提高不粘煤的配入比例,从而直接提高焦炭产量。在降低入炉煤成本的情况下,提高了焦炭品质。     

不同温度下U_3O_8结构的XRD研究

在大气环境及25～850℃条件下，用X射线衍射(XRD)法研究了八氧化三铀(U3O8)的结构变化情况。在实验温度范围内发现，U3O8存在两种相结构，相变温度约为300℃。低于300℃时，U3O8为底心正交结构(Amm2)，在300℃附近转变为对称性更高的简单六方结构(P-62m)。在两种相结构稳定的温度范围内，U3O8的点阵参数随温度的增加呈现出规律性变化。     

支撑体系在城市钢箱梁高架桥施工中的应用

针对闹市区内城市钢箱梁高架桥支撑体系的安装特点,在交通繁忙的道路口施工应考虑减少封道作业,做到"边施工边保通","夜施工日保通"。依据工程现场实际情况,结合钢箱梁结构形式、重量、施工活荷载等要素,选用组合式格构柱支撑体系。支撑体系安装时,通过测量精确定位,在其纵横向设置十字撑保证支撑体系整体稳定性,施工过程中,严格按照施工方案及规范要求实施。采用受力均匀、重复利用等显著特点的组合式格构柱支撑体系,使工程的施工更加经济合理,对类似的城市钢箱梁高架桥施工具有借鉴意义。     

水泥工厂预均化库屋盖柱面网壳悬挑安装方法

通过对跨度49 m预均化库双层柱面网壳进行研究,采用有限元法对网壳小拼单元悬挑安装方法进行了施工全过程数值模拟,考察了悬挑安装过程中网壳结构杆件内力的变化情况,对柱面网壳结构悬挑安装的实际实施提出建议。