Studies on the Dielectric and Transport Properties of PEO/Chitosan Proton Conducting Polymer Electrolyte

1 Results The effect of ammonium nitrate (NH4NO3) content in 40 wt.% PEO and 60 wt.% chitosan blend has been analyzed in this study.The sample containing 40 wt.% NH4NO3 exhibited the highest room temperature conductivity.In order to ascertain that water does not influence the conductivity,the samples were dried in a dessicator and the conductivity determined daily until it shows a constant value.Results are as shown in Fig.1.Samples containing other salt concentrations were also kept in the dessicator f...     

催化剂作用下聚甲基丙烯酸甲酯/聚碳酸酯的反应共混

研究了聚内烯酸甲酯（ＰＭＭＡ）／聚碳酸酯（ＰＣ）共混体系在各种催化剂作用下的反应性溶融共混。考察了不同种类催化剂对ＰＭＭＡ／ＰＣ熔融共混反应的影响,根据共混产物红外分析的结果及共混体系扭矩变化、共混物透明性观察,发现乙酸锂、乙酸镁、硅酸钠、乙酸锰、多聚磷酸、二丁氧基锡、二月桂酸二丁基锡等催化剂能催化ＰＭＭＡ／ＰＣ熔融共混体系两相之间的反应,反应过程中ＰＭＭＡ／ＰＣ接枝共聚物的形成,可以提高两组份的     

青蒿素分子结构的理论研究

文章用量子化学从头算法,研究了青蒿素分子的几何结构,结果表明青蒿素分子的构型、键距、键角、二面角C1-O24-O23-C20等参数与X—射线分析测定值十分接近。为青蒿素及其衍生物的构效研究提供了理论方法。     

液压系统中液压冲击产生的原因及预防措施简

介绍了管路中流动的液体因液流速度突变、运动部件被制动或换向引起的液压冲击,分析了产生液压冲击的原因及危害,提出了预防液压冲击的措施,对提高液压系统工作的可靠性和稳定性提供了理论依据.     

Effects of Polyethylene Oxide Concentration on the Size of Beads in Electrospun Beaded Nanofibers

Embedding particle drugs in beaded nanofibers by electrospinning has been shown a potential approach to control drug release in tissue engineering. The bead size is one of the critical parameters in controlling the drug release rate. In this study,the relationship between polymer concentration and beads size was investigated. Aqueous polyethylene oxide（ PEO） solutions with different concentrations were prepared to obtain various beaded nanofibers by electrospnning. Optical microscope and scanning electron microscope（ SEM） were used to observe the variation tendency of bead size. With an increase in the polymer concentration,the diameter of fibers between beads became bigger,while the fiber uniformity improved. In addition, the polymer concentration influenced the distribution of bead diameter. Higher polymer concentration would reduce the possibility of small-sized beads formation and improve the uniformity of bead diameter. The study provides a possible way to control the size of beads,which is helpful for further research on the control of particle drug release.     

STUDY OF RADIO DEVICES ON 2.4GHZ ISM BAND IN PHYSICAL PHASE

In the unlicensed 2.4GHz ISM band,there is not only IEEE 802.11 wireless systems being used,but also some other devices,such as residential microwave oven,Bluetooth devices,and cordless phone.All these devices that are not used for the data communications cause unintentional interference that will degrade the WI-FI system.In this paper,the transmission powers for common RF devices are measured and the SIR （signal-to-interference ratio） of different interferers to Wi-Fi is also studied.With this information,the effect of different interference on WI-FI signal can hence be quantified.Furthermore,the ability of the interference avoidance protocols,which is built into the AP, to address interference problems caused by that device is determined.     

广义拓扑空间中的μ-正规与g_μ-正规空间

在广义拓扑空间中引入μ-正规和gμ-正规空间的概念,建立它们与μ-Ti空间(i=0,1,2,3,4)之间的关系,并给出了μ-正则空间和μ-正规空间的一些性质.     

聚甲基丙烯酸甲酯颗粒诱导假体周围骨溶解的实验研究

通过破骨细胞培养及动物模型,探讨颗粒诱导假体周围骨质溶解的机制。取SD仔鼠骨髓细胞,在聚甲基丙烯酸甲酯(PMMA)颗粒的刺激下,进行体外破骨细胞培养,然后行TRAP染色,观察颗粒对破骨细胞形态的影响;对骨片上形成的骨吸收陷窝行甲苯胺蓝染色观察并计数。选用24只BALB/c小鼠,在小鼠颅骨部位注入PMMA颗粒,建立骨吸收动物模型。按照注入颗粒的不同随机分为2组,即实验组和对照组,每组12只。2周后处死动物并取材,行HE染色、TRAP染色及TNF-α免疫组化检查。结果显示,PMMA颗粒在体外条件下实验组TRAP染色阳性细胞数及骨吸收陷窝数均较对照组多。动物模型结果显示实验组有明显的骨吸收现象,而对照未发现明显的骨吸收;免疫组化检测亦显示实验组TNF-α较对照组明显。说明PMMA颗粒可诱导假体周围骨质溶解,继而引发假体松动。