一种蓝光单体的合成及其荧光性能研究

吡唑啉衍生物在生物医药[1,2]应用的领域非常广泛.吡唑啉还是一种优质的发光材料[3],其发射波长位于450nm左右,具有很高的荧光量子效率,且发光波长窄,色纯度好,是一种纯正的蓝光.当吡唑啉环3位引入给电子基时,化合物则具有很高的荧光量子产率,可制得具有高热稳定性的空穴传输蓝光发光材料[4-6]和荧光探针[7].它还可以将吸收的不可见的紫外光转变为蓝色的可见光反射出来,从而增加了光线的反射率,使被其处理过的物体白度和光泽提高,所以吡唑啉又被做为荧光增白剂和荧光染料[8,9]进行广泛地应用.     

A novel efficient halogen-free flame retardant system for polycarbonate

A novel silicon- and phosphorus-containing flame retardant, poly (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide siloxane), P(DOPO-VTES) was synthesized from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO) and vinyltriethoxy silane(VTES). Its chemical structure was confirmed by FTIR. The thermal gravimetrical analysis (TGA) showed that P(DOPO-VTES) had good thermal stability and a high of char yield (86.31%) at 700 °C in nitrogen atmosphere. Its XRD patterns showed that this compound had a certain ordered structure. P(DOPO-VTES) was blended with polycarbonate (PC) together with montmorillonite(MMT) to prepare a series of organic-inorganic hybrids of flame retardant (PC)/P(DOPO-VTES)/MMT via melt blending. The thermal degradation behavior and flame retardancy of those hybrids were investigated with TGA, limiting oxygen index (LOI), vertical burning test (UL-94), and cone calorimeter. The LOI value of the flame-retardant PC systems could reach a maximal value of 32.8 when the content of P(DOPO-VTES) was 5 wt%. When 2 wt% MMT was added into the PC/5%P(DOPO-VTES) system, the UL-94 rating reached V-0. The possible flame retardant mode of MMT was studied via the dynamic rheological properties of the systems and the morphology of the chars remaining after the LOI test and the cone calorimeter test.     

High-Tc planar SQUID gradiometer for eddy current non-destructive evaluation

This paper reports the fabrication and test of a high-Tc SQUID planar gradiometer which is patterned from YBCO thin film deposited on a SrTiO3 bicrystal substrate. The measurement of noise spectrum at 77K shows that the white noise at 200 Hz is about 1×10^-4 φ0/√Hz. The minimal magnetic gradient is measured and the results suggest that the minimal magnetic gradient is 94 pT/m. The planar gradiometer is used in non-destructive evaluation （NDE） experiments to detect the artifacts in conducting aluminium plates by performing eddy current testing in an unshielded environment. The effect of the exciting coil dimension on the NDE results is investigated. By mapping out the induced field distribution, flaws about 10mm below the plate surface can be clearly identified.     

Degradation study in flexible substrate organic light-emitting diodes

Indium tin oxide (ITO) coated polycarbonate (PC) multilayer flexible substrates have been subjected to different cycles of bending. Atomic force microscopy (AFM) results on bent ITO surfaces show that bending results in much rougher ITO surfaces. The Ca degradation test shows that the ITO cracks are perpendicular to the flexing direction and that barrier performance deteriorated after bending. When an organic light emitting device is fabricated on the bent substrate, electrical and optical performance decrease. This can be attributed to moisture and oxygen permeated through deteriorated substrate and barrier degraded polymer and oxidized cathode materials. However, optical microscopy observation found that the dark spots have less relationship with the size and position of the cracks on oxide film. Instead to a great extent, they are directly related to the ITO surface spikes. The results further prove that the dark spot is due to electrical stress generated by intense local current at sharp anode and cathode points, which degrade the polymer causing the formation of the dark center. PACS 78.66.Qn; 82.35.Cd; 62.60.Mk     

~(13)C核磁共振研究稀土催化剂聚合双烯的机理

用~(13)C-NMR 方法测定了稀土顺丁二烯和聚异戊二烯链端结构及序列结构,从链端结构推测的聚合活性链端结构与前文是一致的。在聚异戊二烯中存在着“头-头”和“尾-尾”结构,这种结构引起活性链端甲基位置的改变,从而解释了稀土异戊二烯中3,4-链节的形成。测定了不同聚合温度对聚合物中顺、反结构含量的影响,可用活性链端的 anti-syn异构化加以解释。     

周期性声学栅对声子晶体相空间的调控研究

基于周期性声学栅修饰的二维声子晶体,本文从理论上计算其能带结构、等频率色散线,详细讨论引入周期性声学栅后晶体相空间的各种改变.计算结果表明:周期性声学栅的引入能够灵活调制声子晶体的色散关系,更加有效地利用晶体中存在的各种模式,由此可以实现一些较为新颖的声波人工操控.     

一类限制m元over-分拆同余式

We discuss a family of restricted m-ary overpartition functions bm,j （n）, which is the number of m-ary overpartitions of n with at most i ＋ j copies of the non-overlined part m^i allowed, and obtain a family of congruences for bm,lm-1 （n）.     

压电智能梁的阻抗分析与损伤识别

压电陶瓷具有正、逆压电效应,可以用作自驱动传感器.该文对表面粘贴有单片压电陶瓷的压电智能钢梁进行了阻抗分析.讨论了单压电片驱动下钢梁的纵向振动和弯曲振动,得到了压电智能梁的机械阻抗.介绍了压电片与基梁的机电耦合作用及基于压电阻抗技术的结构损伤识别机理.以两端自由钢梁为例对压电智能梁的压电阻抗进行了数值与实验验证,结果表明数值计算结果与实验结果基本相符.利用压电阻抗技术对两端自由的裂纹钢梁进行了损伤识别实验研究,实验结果发现,裂纹的出现引起高频段压电阻抗实部和虚部曲线出现了明显的变化;随着裂纹尺寸的增大,曲线谐振频率和反谐振频率逐渐减小.由此可见,通过测量钢梁损伤前后压电陶瓷片的电阻抗变化能够识别梁中的裂纹损伤.     

Study of 1,3‐Dipolar Cycloaddition and Ring Contraction of New 1,4‐Phenylene‐bis[1,5]benzothiazepine Derivatives

Some 1,4‐phenylene‐bis[1,2,4]oxadiazolo‐[5,4‐d][1,5]benzothiazepine derivatives ( 4a , 4b , 4c ) were synthesized by 1,3‐dipolar cycloaddition reaction of benzohydroximinoyl chloride with 1,4‐phenylene‐bis(4‐aryl)‐2,3‐dihydro[1,5]benzothiazepine ( 2a , 2b , 2c ); meanwhile, compounds 2a , 2b , 2c also occurred ring contraction under acylating condition to obtain bis[2‐aryl‐2′‐(β‐1,4‐phenylenevinyl)‐3‐acetyl]‐2,3‐dihydro[1,5]benzothiazoles ( 3a , 3b , 3c ). The structures of some novel compounds were confirmed by IR, ¹H‐NMR, elemental, and X‐ray crystallographic analysis.