Acyl-chloride functionalized graphene oxide chemically grafted with hindered phenol and its application in anti-degradation of polypropylene

In this study,graphene oxide (GO) nanosheets were first functionalized by the acyl-chloride reaction and then reacted with hindered phenol (HP) to obtain HP grafted GO (GO-g-HP).The GO-g-HP prepared under the optimized condition exhibited a high efficiency against both thermal and photo oxidation of isotactic polypropylene (iPP).GO-g-HP exhibited a much better anti-aging efficiency than that of HP and GO used individually or that of their physical mixture.The outstanding anti-aging effect of GO-g-HP was attributed to the excellent synergistic effect produced between the chemically bonded GO and HP,which resulted in an improved oxygen barrier property of GO and excellent utilization of the free radical scavenging capability of GO and HP.Also,thanks to the grafting of HP on GO,the physical loss of HP,which was one of the main shortcomings for traditional small molecular antioxidants,was largely suppressed.It is expected that the GO-g-HP prepared can well meet the requirement of long-term applications of polymers in some harsh service conditions.     

一价金属Ag、Au同步辐射光激发下的室温和低温光电子能谱分析

文章的实验采用同步辐射光源的能量范围60-200eV,分别测定单晶Ag的3d、4p、4d和5s电子以及研究其能带和谱峰的性质,分析给出Ag的光电子能谱的半高峰值的宽度。分析Ag在室温和低温下光电子能谱产生差异,以及低温下Ag的光电子能谱的性质。最终比较得出Ag、Au各个价带产生的光电子能谱谱峰中单色性最好的谱峰。计算出Ag导带的宽度与实验值进行比较。     

光电效应实验方法的改进

用通常的实验装置演示光电效应现象，由于所产生的光电流很弱，因而现象不明显，不易观察，我们在原有的实验装置中增加了一个放大电路，将光电流加以放大，从而改进了实验效果，本文介绍用改进后的装置，演示实验的情况。     

运用像素点法进行效能分析研究

针对基于实物图片进行模拟射击的效能分析问题,提出了运用像素点法进行蒙特卡罗模拟的方法,研究了基于实物图片运用像素点法进行效能分析的步骤和运用Matlab软件编程实现的方法,并通过实例分析进行了仿真验证。     

摻铟氧化铕光学特性的研究

采用溶胶-凝胶制备了非晶氧化铕及摻杂铟离子的氧化铕. 利用X-射线衍射谱、光致发光谱、荧光光谱对其性质进行表征. 铕的5D0 →7FJ(J=0, 1, 2, 4, 5, 6)发射被观测到,并对加入等摩尔分数的铟离子和铕离子,600 ℃退火的样品变温光致发光谱进行了研究. 不同掺杂浓度的非晶Eu2O3在600 ℃退火时的光致发光谱均在615 nm和619 nm处出现强发射,随着掺杂浓度的提高,615 nm处发光增强,619 nm处发光减弱,峰位没有改变,其中以少量掺杂(xIn=0.01)非晶Eu2O3光致发光强度最强.     

光敏电路在控制汞电极形成过程的应用

在一个新设计的以汞为电极流动注入分析体系中,蠕动泵不能提供恒定流速,因而常用的时钟法已很难准确地控制体系,为此,采用了光敏耦台器来代替时钟控制整个分析体系,与时钟法比较,流动体系的流速对光敏电路的影响不大,因而系统控制过程更接近该体系的设计要求。     

摄影"分离主义"与斯蒂格里茨

早期的摄影依附于绘画,绘画主义长期支配着摄影创作的方向。1891年,受爱默森“自然主义摄影”理论的影响,一场从对绘画的依附中独立出来的摄影“分离主义”运动从英国肇始,迅速蔓延到欧洲和美国,并在斯蒂格利茨的推动下,成为一种自觉的长达四分之一世纪的现代艺术运动,直接催生了现代摄影艺术的诞生。斯蒂格利茨也被当之无愧地誉为“当代摄影之父”。     

便携式红外测尘仪的研制

粉尘是环境和工业现场的重要污染物,粒径在几个μm以下的呼吸性粉尘可进入人体肺部造成尘肺病和矽肺病.为了保障居民和工人的健康,有关部门制定了相应标准,要求把环境的粉尘浓度控制在这一标准之下.空气中的含尘量用粉尘浓度来表示,单位为mg/m~3.最常用的测尘方法是采样称重法,此法简单直观.现行国家标准就是依据它制定的.其缺点是:a.操作繁琐,易受主观因素影响;b.不能实时给出结果;c.仅用粉尘重量表示其对人体的危害程度是不全面的;d.不能自动测量,在现场应用也很不便等.因此迫切需要研制能实时给出结果的“快速测尘仪”.     

Sulfurized hematite for photo-Fenton catalysis

A hematite/amorphous sulfur composite was prepared via simple heating hematite and α-sulfur in Teflon-lined autoclave at low temperature. The composite was characterized by X-ray diffraction(XRD), Raman spectrum,Thermal Gravity Analysis(TGA), Transmission Electron Microscopy(TEM) and X-ray photoelectron spectroscopy(XPS). The results revealed that an allotrope sulfur at 5-37% weight percent was found in the composite.After sulfuration, S_n~(2-) or S_2~(2-) was doped in the lattice of hematite, large amounts of OH and SO_4 were adsorbed on the surface of hematite. Hematite/amorphous sulfur composite had superior photo-Fenton activities than pure hematite. This work also demonstrated that amorphous sulfur also had the activity of photo-Fenton catalysis. OH~-and SO_4 radicals facilitated dye adsorption and acted as a bridge to link H_2 O_2. Moreover, SO_4 radicals on hematite served as electron trapping center that can receive photo-induced electron from conduction band of hematite and transfer it to the adsorbed H_2 O_2, increasing the rate of photo-Fenton reaction eventually.