Zn0.76Cd0.24Se/ZnSe多量子阱的共振喇曼光谱

本文报道了在Zn0.76Cd0.24Se/ZnSe多量子阱(MQWs)中,用不同的Ar+激光线激发,观察到了共振增强的喇曼散射。首次在室温和77K的条件下,用Ar+的457.9nm谱线激发,观察到分别来自ZnSe垒层和Zn0.76Cd0.24Se阱层的限制纵光学声子模(LO)的喇曼散射,并对上述不同的光学模的起因进行了分析。     

低密度聚乙烯光引发交联机理——Ⅱ.BNB自旋捕捉ESR研究

在光引发剂二苯甲酮(BP)存在下,紫外光辐照低密度聚乙烯(LDPE)所形成的自由基中间体已被自旋捕捉剂2,4,6-三特丁基亚硝基苯(BNB)所捕捉,其自旋加合物自由基已为电子自旋共振(ESR)所特征。现已检测和鉴定到二种自旋加合物:一种是叔碳自由基;另一种是仲碳自由基。它们分别是由BP的激发三重态从LDPE链的支化点和亚甲基团上夺氢所形成的自由基中间体同自旋捕捉剂BNB反应生成的。上述的证据表明:LDPE的光引发交联点主要发生在叔碳和仲碳原子上,且H-型交联点占主导地位。     

Facile cyclic ammonium salt with the smallest size for high performance electric double layer capacitors

A novel cyclic ammonium salt, N,N-dimethylpyrrolidinium tetrafluoroborate (P₁₁-BF₄), was successfully synthesized for the first time. The smallest cyclic structure of P₁₁-BF₄ induced high solubility and conductivity in PC, which can easier enter the micropores of activated carbon and occupy more surface area during charge/discharge process.     

Oligomerization and Polymerization of Ethylene Initiated by a Novel Ni(Ⅱ)-Based Acetyliminopyridine Complexes as Single-Site Catalysts

Novel Ni(Ⅱ)-based acetyliminopyridine complexes 1b, 2b, 3b (1-3b), which are synthesized from ligands 1a, 2a, 3a (1-3a) and [NiCl2(DME)], are suitable precursors for the catalysts that are necessary for ethylene oligomerization and polymerization reactions, activated by methylaluminoxane (MAO). The MAO-treated 1-3b presents an active catalytic center, which may oligomerize and polymerize ethylene to produce linearα-olefins and polyethylene, respectively. The molecular weight distributions of oligomers that are obtained are in good agreement with the Schulz-Flory rules for oligomers>C4. The activity of 3b-MAO complex is 6.3×107 g/(molNi·h) at 50℃. The activities and molecular weight distributions of oligomers show significant reliance on the structures of catalyst precursors.     

基于核酸的纸基荧光生物传感器的设计及应用

纸基生物传感器由于其具有成本低、操作方便、生物可降解、识别元件用量低等优点,近年来受到了广泛的关注。其中,以功能核酸作为识别元件的纸基荧光生物传感器具有较高的灵敏度、瞬时响应以及实时检测等特性,在便携式传感设备方面展现出巨大的潜力。此外,将核酸作为识别元件的纸基无细胞蛋白合成平台,通过条件合成的报告荧光蛋白可实现对病毒、重金属等目标物的特异性检测,具有良好的应用前景。首先,本文介绍了基于核酸的纸基荧光生物传感器的设计,特别是基于核酸的识别元件与纸基材料的结合方式。其次,总结了基于核酸的纸基荧光生物传感器在临床诊断、食品安全检测、环境污染物检测等不同领域的最新研究进展,讨论了其优势与局限性。最后,探讨了基于核酸的纸基荧光生物传感器的发展方向与应用前景,以期为相关领域的研究提供参考。     

Preparation of modified multi‐walled carbon nanotubes as a reinforcement for epoxy shape‐memory polymer composites

Effectively improving the mechanical properties and thermal resistance of epoxy shape‐memory polymers (ESMPs) without affecting their shape‐memory performance is necessary to expand these polymers in practical applications. In this article, modified multi‐walled carbon nanotubes (MWCNTs) were prepared and used as efficient reinforcement for enhancing the comprehensive properties of ESMPs. Increases of nearly 289% to 444% for impact strength and 112% to 184% for tensile force were obtained by adding only 0.1 to 1 wt% epoxy‐modified MWCNTs. The addition of unmodified and carboxyl‐modified MWCNTs was also investigated but showed less impact on the mechanical properties of the ESMPs than epoxy‐modified MWCNTs. Thermogravimetry analysis (TGA) and dynamic mechanical analyses (DMA) showed that less than 1 wt% modified MWCNTs can enhance the heat resistance of ESMPs greatly. Although the shape recovery time for composite materials increased upon adding the MWCNTs, the entire recovery time was still less than 1 minute, and the shape recovery rate was relatively high, nearly 100%.     

Zn1-xCdxSe-ZnSe多量子阱的光学双稳态

用常压MOCVD法在GaAs衬底上生长了Zn_1-xCd_xSe-ZnSe多层结构.通过X-射线衍射谱和光致发光等方法判断,表明该材料为多量子阱结构.从室温下的透射光谱上可以观察到这种多量子阱中的n=1的激子吸收峰,并观测到起因子激子的ns量级的光学双稳态.     

A note on regularity for a class of quasilinear elliptic equations

The following regularity of weak solutions of a class of elliptic equations of the form are investigated.     

Detection of air target based on multi-fractal analysis in a laser radar

A novel approach for detecting laser radar target based on multi-fraction dimension (MFD) of laser clutters has been proposed. The fractal dimension (FD) of laser clutter and the echoes from the plan are estimated using box-counting dimension algorithm. The intrinsic difference in the spectrum of FD Dq between them is extracted and used to detect targets. Experimental results show that the method based on MFD is more reliable than that on FD and can improve the accuracy of detection.