Comparison study of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres

To compare two microspheres of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin loaded theophylline as pulmonary sustained drug delivery carriers, the characteristics and ciliotoxicity were studied. The drug loadings of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres were 21.09% and 21.42%, and the encapsulation efficiencies were 91.40% and 92.80%. The distributions of 50% (d _0.5) of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres were 4.89 and 5.83 μm, respectively. Both microspheres showed spherical shape with smooth or wrinkled surfaces. FT-IR of chitosan/β-cyclodextrin microspheres demonstrated that theophylline had formed hydrogen bonds with chitosan and β-cyclodextrin, while for the carboxymethyl chitosan/β-cyclodextrin microspheres theophylline had interaction with carboxymethyl chitosan. The moisture absorption showed that an equilibrium was reached within 24 h. The two microspheres possessed better adaptability. In vitro release of theophylline from chitosan/β-cyclodextrin microspheres was slower than that from carboxymethyl chitosan/β-cyclodextrin microspheres at pH 6.8. Biography: LI Ruobao(1968–), male, Associate professor, research direction: foundation research of respiratory system.     

海子抒情诗中“秋”意象解析

海子诗歌意象丰富,意蕴深厚,极具艺术张力,例如“秋”意象。本文从三方面论述海子抒情诗中“秋”意象。首先,“秋”象征丰收而荒凉的人世;其次,论述“秋”的感伤;最后,“秋”是幻象丛生的国度。     

Banach空间一类非线性算子方程的不动点

利用锥理论和非对称迭代方法,讨论了不具有连续性和紧性条件的非线性算子方程A（x,x）＋u0=Bx解的存在唯一性,并给出了迭代序列收敛于解的误差估计,所得结果是某些已知结果本质改进和推广．     

一类半线性椭圆方程组非平凡解的不存在性

一类半线性椭圆方程组：{△u（x）＋f1（u（x））g1（v（x））=0 x∈Ω △v（x）＋f2（u（x））g2（v（x））=0 x∈Ω u（x）＋v（x）=0 x∈aΩ其中,Ω R^N是关于0的星形区域f1、f2、g1、g2：R→R＋为非负函数．在一定条件下,它的非平凡解是不存在的．     

汤旺河干流水电站规划二氧化硫减排量的分析和计算

开发水电资源,可以替代火电,减少二氧化硫的排放量,为节能减排做出积极地贡献．根据汤旺河干流水电规划,尝试对规划实施后替代的二氧化硫减排量进行分析和计算．     

松花江水污染模型的数值研究

研究参考文献[4]中干支流水系统所建立的反应扩散方程组.使用傅里叶级数方法,在不同条件下对此方程组的解进行数值模拟.     

Distributed modeling of the beginning and ending dates and durations of limited temperatures over the rugged terrain of Chongqing

A physically based empirical model was established for the beginning and ending dates (BED) of limited temperatures.Data used were daily mean temperatures from 34 conventional stations in the Chongqing region,measured from 1961 to 2000.Using this model in combination with the distributed modeling results of monthly mean temperatures,we developed a method for creating a distributed simulation of the BED and durations of limited temperatures in the rugged terrain of Chongqing.Spatial distribution maps were generated at a resolution of 100×100 m for the BED and durations of the limited temperatures of 0,10,15 and 20.Simulations suggest that the distributed model is able to successfully reveal the macroscopic trends and local distributions.For the modeled BED,the mean absolute bias error is 0.6-2.4 d.Cross-validation and case-year tests show mean absolute bias errors of 1.3-2.8 d and 0.7-2.5 d,respectively.Comparison shows that the simulation results are consistent with the field investigations.This implies that the simulations are as good as observations,thus providing a viable technique for simulating mountainous heat resources using conventional meteorological data.     

我国电子政务的发展与研究

目前,电子政务已成为世界许多国家和地区政府追求的目标和关注的焦点,我国的电子政务同样也得到了党和国家的高度重视,并成为国家信息化建设中极为重要的组成部分。本为首先介绍了我国电子政务的发展历程,然后经过深入研究总结出我国电子政务存在的问题,并提出相应的解决措施。     

离心级联供料扰动过程中丰度分布的数值模拟

为了得到离心级联流体状态变化时同位素丰度分布情况,建立了丰度变化下的动态数学模型,与水力学数值模拟进行耦合,利用Q迭代算法求解了动态丰度方程。Xe分离数值模拟结果表明,该模型和算法可以有效求解离心级联动态丰度分布。在扰动幅度和持续时间都相同的情况下,丰度的变化与该组分在同位素中的位置、距离扰动级的位置、机器滞留量以及稳态下丰度的分布情况都密切相关。研究结果可供实际同位素生产中参数分析和调整时参考。     

Research on catalysis of sodium-metallochlorophylls in Ni/MH battery

The effects of sodium-metallochlorophylls including sodium-iron chlorophyllin, sodium-copper chlorophyllin and sodium-magnesium chlorophyllin on performance of Ni/MH battery were investigated. The results show that sodium-iron chlorophyllin can effectively activate the gases produced during charge in Ni/MH battery, therefore reducing the reduction potential of oxygen and the oxidation potential of hydrogen, and the increased speed of inner pressure of battery is decreased significantly. With the aid of DMol3 software, the activation process of oxygen and hydrogen by sodiummetallochlorophylls was simulated and analyzed. It was found that the catalysis behavior is in agreement with the experimental results, and the activation process also gets a reasonable explanation from the calculated results.