Influence of ethyl methacrylate content on the volume‐phase transition of temperature‐sensitive poly[(N‐isopropylacrylamide)‐co‐(ethyl methacrylate)] microgels

A novel series of temperature‐sensitive poly[(N‐isopropylacrylamide)‐co‐(ethyl methacrylate)] (p(NIPAM‐co‐EMA)) microgels was prepared by the surfactant‐free radical polymerization of N‐isopropylacrylamide (NIPAM) with ethyl methacrylate (EMA). The shape, size dispersity and volume‐phase transition behavior of the microgels were investigated by transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy, dynamic light scattering (DLS) and differential scanning calorimetry (DSC). The transmission electron micrographs and DLS results showed that microgels with narrow distributions were prepared. It was shown from UV–Vis, DLS and DSC measurements that the volume‐phase transition temperature (VPTT) of the p(NIPAM‐co‐EMA) microgels decreased with increasing incorporation of EMA, but the temperature‐sensitivity was impaired when more EMA was incorporated, causing the volume‐phase transition of the microgels to become more continuous. It is noteworthy that incorporation of moderate amounts of EMA could not only lower the VPTT but also enhance the temperature‐sensitivity of the microgels. The reason for this phenomenon could be attributed to changes in the complicated interactions between the various molecules. Copyright © 2004 Society of Chemical Industry     

Experimental investigation of adhesive meltblown web production using accessory air

Using a low‐melting‐point polymer, copolyamide, as raw material, adhesive meltblown webs were formed on the ordinary melt‐blowing line by using the accessory air and the accessory air chamber. The webs thus produced exhibit narrower fiber diameter distribution and a more uniform pore structure. At the same time, four main melt‐blowing parameters, the primary air pressure, the accessory air pressure, the melt throughput rate, and the die‐to‐collector distance, are discussed in terms of their influence on geometric mean diameter of fibers and fiber diameter distribution. POLYM. ENG. SCI., 46:1–7, 2006. © 2005 Society of Plastics Engineers     

Array SSL VPN如何保障番禺有线办公网的安全运行

企业办公自动化系统的应用十分广泛,随着互联网的高速发展,WEB应用成为主流,OA系统在互联网上的延伸成为大趋势,本文阐述在WEB应用中如何保障数据和系统安全的手段和方法。     

聚乙烯醇修饰维生素E脂质体的制备及性质研究

用乳化法制备聚乙烯醇修饰的包封维生素E的脂质体,考察了脂质体的形态、包封率和脂质体在4℃、25℃以及在与皮肤类似条件下的稳定性.实验结果表明,脂质体为圆球状,包封率为86.42%.聚乙烯醇的修饰增加了脂质体的稳定性,在4℃下可以稳定储存90d.泄漏率为4.88%.脂质体通过融合、聚结和泄漏缓慢释放包封的维生素E,并且其泄漏率随着pH的减小、Ca2-浓度的增加和储存时间的增加而增加,在pH＜5.0和c(Ca2 )＞6.0mmol/L时脂质体的泄漏加快.     

在 AUTO CAD 中实现零件轮廓数控自动编程

介绍了在ＡＵＴＯＣＡＤ系统中用ＡＵＴＯＬＩＳＰ语言对图形实现数控铣自动编程的方法，实现图形交互式数控机床自动编程。     

Synthesis and characteristics of SiC whiskers with “rosary bead” morphology

SiC whiskers with ″rosary bead″ morphology were synthesized using suitable silicon source and carbon source through solid reaction at the temperature above 1537 K. The diameter and length of the SiC whiskers were about 0.1-1.0 μm and 20-100 μm,respectively. The largest diameter of their enlarged ends of the whiskers was about 0.2-1.0 μm, and it gradually and smoothly decreased to the size of the plain part of the whiskers. The results of X-ray diffraction analysis show that the crystalline structure of the obtained SiC whiskers is β-SiC. It is considered that the SiC whiskers grow via a vapor-solid mechanism.     

高职高专“计算机应用”专业教改可行性研究

高职高专“计算机应用”专业建设是通过专业整体建设来强化专业的可持续性发展,提升技能人才培养能力。通过高职高专“计算机应用”专业教改可行性研究,清晰的可以看到随着专业建设的深入与教学实践的展开,最终目标是为社会提供满足职业岗位能力需求的合格的毕业生和技能人才。     

UpG法用于辐射损伤的量效关系研究

应用常规染色体制作法和紫外线照射加吉姆萨染色法(Ultraviolet plus GienlSa technology,UpG)检测经60Coγ射线离体照射后的人外周血淋巴细胞染色体畸变率(双着丝粒体 环),研究其剂量-效应关系,探讨UpG法用于辐射损伤的剂量估算效果.实验结果表明:两种方法得出的染色体畸变率与照射剂量密切相关(P<0.05),均可用于辐射损伤的量效关系研究.两种方法的结果相比,在同一照射剂量下,UpG法高于常规法,具有显著性差异(P<0.05).UpG法可以很好用于辐射损伤的剂量估算中,且较为准确、灵敏.     

可见分光光度检测离子色谱仪分析铬鞣液中铬含量

本文介绍了用可见分光光度检测离子色谱仪分析铬鞣液中铬含量,允其适用于大量样品的连续分析。实验证明,该方法精密度高,变异系数0.32%,线性关系好,回收率为98～100.25%,准确,快速,方便是该方法的特点。