PPV衍生物的合成及其在太阳能电池方面的研究进展

聚合物太阳能电池成为太阳能电池发展的重要方向,本研究针对聚合物太阳能电池材料中颇受关注的聚对苯乙炔(PPV)衍生物,综述了PPV衍生物的合成方法,简要介绍了聚合物太阳能电池的研究现状及存在问题,展望了聚合物太阳能电池的研究方向。     

电致发光材料PPV的合成研究──Ⅰ.PPV前驱聚合物的合成

报道了新型电致发光材料-聚对苯撑乙烯前驱聚合物的合成方法。研究了各中间体的合成工艺。并对前驱聚合物进行了性能测试，结果表明所选择的合成方法合理可行，并为PPV的合成提供参考数据。     

聚对芳撑次乙烯基聚合物

在高分子聚合物中引入刚直性链,可使聚合物的强度和弹性模量大大提高,特别是主链含有对苯撑基和次乙烯基共轭双键的高分子聚合物,具有优良的力学性能,优良的导电性能,以及光电传导性能。其中聚(对苯撑次乙烯基)聚合物(简称 PPV),由于采用了高分子锍盐中间体的制备路线,大大改变了用以往合成方法只能得到聚合度低的不溶不熔聚合物,且难于成型加工的困难局面。由新方法制得的PPV 聚合物加工成型容易,可制薄膜、纤维,用作各种有机光电元件,电子元件,以及近年来已具有实际意义的电发光材料及非线性光学元     

聚合物主体材料在磷光有机电致发光器件中的研究进展

综述了近几年用于磷光有机电致发光器件的聚合物主体材料的研究进展,着重介绍了聚咔唑类主体材料、聚芴类主体材料、聚苯乙烯类主体材料和聚间苯基类主体材料的结构单元的设计与修饰以及磷光器件性能的研究进展。同时,还展望了磷光聚合物主体材料的发展前景,提出了今后磷光聚合物主体材料的发展方向。     

热致调光聚合物材料进展

热致调光聚合物材料能随环境温度变化发生可逆的透明度或颜色转变,从而广泛应用于智能窗、温度传感器及热可逆记录等热光学领域.现有的各种热致调光聚合物材料主要分为热致散射、热致变色以及双功能3类.详细介绍了近年来这3类热致调光聚合物材料的研究状况,分析了其调光机理及性能,并展望了其未来的发展.     

主链含三苯胺链段的TPA-DHPPV共聚物的合成及表征

合成了2,5-二氯甲基-1,4-二己氧基苯、1,4-二己氧基-2,5-二甲苯双(三苯基氯化季膦)和4',4-三苯胺二醛3种单体.通过聚合反应制得了聚1,4-二己氧基对苯乙炔(DH-PPV)和含三苯胺链段的PPV类共聚物(TPA-DHPPV),对聚合物进行了结构表征和性能测试.DH-PPV和TPA-DHPPV聚合物物质结构准确,在紫外光激发下能发出强的蓝绿光,荧光光谱表征说明该类聚合物均能发射较强的荧光,电致发光器件的伏安特性测试表明该类聚合物具有较低的驱动电压和较高的发光亮度,并且该类聚合物具有较高的热稳定性.     

基于TNT敏感聚合物的纳米阵列结构的制备与性质

利用多孔氧化铝模板法制备了两种1,3,5-trinitrotoluene(TNT)敏感的荧光共轭聚合物Tri-phenylamine-CO-para-biphenyene vinylene(TPA-PBPV)和Triphenylamine-co-para-phenyl-ene vinylene(TPA-PPV)的纳米线阵列结构.纳米线的直径在80～100 nm之间,高度在150-200nm之间.和固体薄膜相比,TPA-PBPV和TPA-PPV荧光光谱都发生了蓝移,TPA-PBPV的发射峰从485变为455 nm,PPV的峰从495 nm变为475 nm.蓝移的发光表明聚合物纳米线阵列可以抑制低能量陷阱,有望提高材料的传感性能.     

用于光伏电池上的新型高分子PPV材料

聚对苯乙烯撑(PPV)由于具有优良的光电性质,是研究最多也是最有希望的光伏材料之一.然而单纯PPV作为光伏材料存在对太阳光利用率不高、载流子迁移率较低、稳定性不高等缺陷,制约了其实际应用.因此在围绕提高光伏效率和材料稳定性等基础上,近几年出现了大量PPV改性光伏材料.分析了新型PPV的各种改性措施的目的和相应的分子结构修饰方法,同时探讨了PPV光伏材料尚存在的问题和它作为高分子光电池材料的发展前景.     

Gilch法合成聚对苯乙炔缺陷及分子量的控制

聚对苯乙炔及其衍生物由于具有独特的导电性和荧光特性,目前广泛应用于有机光致器件、激光器件以及光探测器等领域.Gilch法合成聚对苯乙炔材料中往往存在缺陷,这些缺陷对材料及器件的光电性能产生影响.综述了控制PPV凝胶及苄基-二苯乙炔缺陷的方法,介绍了PPV分子量的影响因素.     

一种新型PDLC薄膜电-光性能的研究

选用丙烯酸胆固醇酯/甲基丙烯酸β-羟乙酯/液晶复合体系,在紫外光照射下制备聚合物分散液晶薄膜.研究了两种丙烯酸酯类单体的配比对聚合物分散液晶薄膜的电-光性能的影响规律,由此确定了制备综合电-光性能优异的PDLC薄膜材料的最佳制备条件.     

Chromatographic characteristics of surfactant-mediated separations: micellar liquid chromatography vs ion pair chromatography.

The effects of concentrations of organic solvent and surfactant on elution strength and selectivity in MLC and IPC are studied. It is observed that selectivity between most pairs of solutes used in this study increases in MLC and either decreases or passes through a minimum in IPC, with the volume fraction of organic modifier. In both MLC and IPC, selectivity varies with surfactant concentration; however, the overall variation in selectivity and elution order are more pronounced in MLC. The solvent strength decreases in IPC and increases in MLC as a result of an increase in surfactant concentration. An iterative regression design is used to predict the optimum mobile-phase compositions in terms of solvent strength and selectivity. The correlation between the predicted and measured chromatograms is excellent in MLC and poor in IPC. This is due to a more regular and reproducible retention behavior in MLC which greatly facilitates the development of robust methodologies. For a mixture of amino acids and peptides, a large retention gap between the first and the last eluting solutes is observed in IPC, which makes the use of organic solvent gradient inevitable. However, a better separation for the same mixture of solutes can be achieved in MLC isocratically. Apparently, the general elution problem can be alleviated in MLC by using an optimum eluent composition. It is observed that the efficiencies of MLC and IPC are comparable. The above observations indicate that MLC can be a powerful alternative to IPC in order to achieve optimized separations in shorter analysis time.     

FGH96合金反复镦拔与挤压缺陷对比分析

对FGH96合金反复镦拔变形与挤压变形两种制坯工艺的夹杂缺陷水平进行了比较,并分析了不同变形状态下非金属夹杂物的形变特性。结果表明:反复镦拔变形后,锻件内检测到的非金属夹杂物数量有不同程度的增多,超标缺陷成倍增长;而FGH96合金挤压+等温锻造变形后,锻件内检测到的非金属夹杂物数量明显减少,纯净度水平有大幅提高。从微观夹杂物形貌的变形特性来看,等温锻造变形时在垂直于变形方向合金中夹杂物缺陷的尺寸增大;反复镦拔变形时,合金中原有非金属夹杂物缺陷聚集使可检测到的缺陷面积增大;而在挤压变形过程中,夹杂物缺陷在挤出方向被拉长成不连续的线状,每个方向上夹杂物的面积均减小;FGH96合金挤压+等温锻造变形后夹杂缺陷的大小主要由挤压变形后夹杂缺陷破碎情况决定;因此大挤压比变形可有效破碎合金中非金属夹杂物,改善锻件质量。     

5G时代动态可变式校标设计及延展应用

目的探讨5G时代中国高校如何通过具有高识别度和多元变化的校标设计及延展应用,提升中国高校的国际品牌形象,助力中国高校的国际化进程。方法通过比较研究中国137所“双一流”高校与QS世界大学排名前100强高校的校标,以图像分析和统计学的方法揭示中国高校校标设计高度雷同化、辨识度低的现状,指出常见的圆形范式校标在国际竞争和品牌传播中所存在的局限性;借鉴西方品牌形象设计的成功案例,寻找5G时代中国高校校标设计的创新理念、设计方向以及具体的延展应用方法。结论强调独特性、高识别性的校标设计在高校品牌传播中的重要性,并创造性地提出了“动态可变式”校标设计及延展应用在5G时代必将成为高校品牌形象传播的主流趋势和重要手段。     

Leukaemia following childhood radiation exposure in the Japanese atomic bomb survivors and in medically exposed groups

Incidence and mortality risks of radiation-associated leukaemia are surveyed in the Japanese atomic bomb (A-bomb) survivors exposed in early childhood and in utero. Leukaemia incidence and mortality risks are also surveyed in 16 other studies of persons who received appreciable doses of ionizing radiation in the course of treatment in childhood and for whom there is adequate dosimetry and cancer incidence or mortality follow-up. Relative risks tend to be lower in the medical series than in the Japanese A-bomb survivors. The relative risks in the medical studies tend to diminish with increasing average therapy dose. After taking account of cell sterilisation and dose fractionation, the apparent differences between the relative risks for leukaemia in the Japanese A-bomb survivors and in the medical series largely disappear. This suggests that cell sterilisation largely accounts for the discrepancy between the relative risks in the Japanese data and the medical studies. Excess absolute risk has also been assessed in four studies, and there is found to be more variability in this measure than in excess relative risk. In particular, there is a substantial difference between the absolute risk in the Japanese atomic bomb survivor data and those in three other (European) populations. In summary, the relative risks of leukaemia in studies of persons exposed to appreciable doses of ionizing radiation in the course of treatment for a variety of malignant and non-malignant conditions in childhood are generally less than those in the Japanese A-bomb survivor data. The effects of cell sterilisation can largely explain the discrepancy between the Japanese and the medical series.     

北京城区和远郊区大气细颗粒PM_(2.5)元素特征对比分析

为了对比大气悬浮颗粒PM2.5及其所含元素在北京城区与远郊区的特征,在2007年不同季节和2008年北京奥运会期间进行了PM2.5的采样分析。结果表明:城区PM2.5和元素的浓度均高于郊区,元素浓度在城区与郊区具有不同的季节变化特征,春、冬季地壳元素浓度在城区与郊区都有所增加,在城区S元素和其它污染元素在秋、冬季最高,而郊区S元素浓度在夏季最高。污染元素的富集程度夏秋季高于春冬季,郊区高于城区,城、郊两地PM2.5中元素来源相似。雾霾天PM2.5及元素浓度在城区增加明显,奥运期间污染元素的质量分数较奥运前明显降低。     

21世纪之初工程哲学在东西方的同时兴起

科学哲学和技术哲学都是首先在欧美国家兴起的,可是,工程哲学却是于21世纪之初在中国和欧美发达国家同时兴起和基本同步发展的。文章简要介绍了2002年以来工程哲学在中国和欧美国家发展的重要事件和已经发表的重要著作,最后,简要评论了东、西方工程哲学发展的主要特点。     

铝合金的动态再结晶

本文展现了当前铝及铝合金动态再结晶研究的一些进展。分析了铝合金动态再结晶的特点和材料状态,形变条件对动态再结晶的影响。指出了铝合金动态再结晶研究在理论,实际生产中的意义和铝合金动态再结晶研究的方向。     

Osteoarthritic process modifies expression response to NiTi alloy presence

Nickel-titanium alloy (nitinol, NiTi) is a biomaterial with unique thermal shape memory, superelasticity and high damping properties. Therefore NiTi has been used in medical applications. In this in vitro study, the effect of NiTi alloy (with two surface modifications – helium and hydrogen) on gene expression profile of selected interleukins (IL-1β, IL-6 and IL-8) and matrix metalloproteinases (MMP-1 and MMP-2) in human physiological osteoblasts and human osteoarthritic osteoblasts was examined to respond to a question of the different behavior of bone tissue in the implantation of metallic materials in the presence of cells affected by the osteoarthritic process. The cells were cultivated in contact with NiTi and with or without LPS (bacterial lipolysaccharide). Changes in expression of target genes were calculated by 2^-ΔΔCt method. An increased gene expression of IL-1β in osteoarthritic osteoblasts, with even higher expression in cells collected directly from the metal surface was observed. In case of physiological osteoblasts, the change in expression was detected after LPS treatment in cells surrounding the disc. Higher expression levels of IL-8 were observed in osteoarthritic osteoblasts after NiTi treatment in contact with alloy, and in physiological osteoblasts without relation to location in combination of NiTi and LPS. IL-6 was slightly increased in physiological osteoblastes after application of LPS. MMP-1 expression level was obviously significantly higher in osteoarthritic osteoblasts with differences regarding the metal surface and location. MMP-2 expression was decreased in both cell lines after LPS treatment. In conclusion, results of present study show that the NiTi alloy and the treatment by LPS, especially repeated doses of LPS, change the gene expression of selected ILs and MMPs in human osteoblast cell cultures. Some of the changes were depicted solely to osteoarthritic osteoblasts.     

Quantum Communication Networks and Trust Management: A Survey

This paper summarizes the state of art in quantum communication networks and trust management in recent years. As in the classical networks, trust management is the premise and foundation of quantum secure communication and cannot simply be attributed to security issues, therefore the basic and importance of trust management in quantum communication networks should be taken more seriously. Compared with other theories and techniques in quantum communication, the trust of quantum communication and trust management model in quantum communication network environment is still in its initial stage. In this paper, the core technologies of establishing secure and reliable quantum communication networks are categorized and summarized, and the trends of each direction in trust management of quantum communication network are discussed in depth.     

功率超声在金属熔体成形中的作用效应及其可视化研究进展

主要介绍功率超声在金属熔体成形领域中的作用,详述了超声在铸造成形、辅助焊接成形中细化晶粒、除气除杂、强化焊缝、减小残余应力、促进界面润湿等方面的应用和作用机理。针对超声空化气泡的高速摄影及金属熔体中晶体生长的同步辐射X射线成像观察的研究进展,提出将高速摄影与同步辐射X射线成像结合起来,通过原位观察方法研究超声波与液态金属媒质的相互作用机理,为进一步促进超声在金属熔体成形中的应用提供理论指导。