A recyclable fluorescence sensor for Hg2+ and Zn2+, based on rhodamine 6G(R6G) and 8-aminoquinoline(8-AQ) co-modified core/shell Fe3O4@Si O2 nanoparticles(denoted as R6G/8-AQ co-functionalized Fe3O4@Si O2 NPs), was developed. R6 G derivative and 8-AQ derivative were conjugated onto the water-soluble core/shell Fe3O4@Si O2 nanoparticles(NPs) by covalent interaction. The R6G/8-AQ co-functionalized core/shell Fe3O4@Si O2 NPs showed fluorescence emission bands at 548 and 480 nm. When the R6G/8-AQ co-functionalized core/shell Fe3O4@Si O2 NPs were coordinated with Hg2+ and Zn2+, emission intensity at 548 nm increased with [Hg2+], while that at 480 nm increased with [Zn2+]. Moreover, there existed approximate linear relationships between fluorescence intensities and concentration of metal ions, in the range of 4.0×10-9–7.65×10-8 M for Hg2+ and 3.3×10-9–3.96×10-8 M for Zn2+, respectively. The lower detection limits for Hg2+ and Zn2+ were 1.0×10-9 and 3.0×10-9 M, respectively. The R6G/8-AQ co-functionalized core/shell Fe3O4@Si O2 NPs showed good selectivity to Hg2+ and Zn2+ over other common metal ions examined in neutral aqueous solutions. Moreover, the R6G/8-AQ co-functionalized core/shell Fe3O4@Si O2 NPs could be recycled from the detected samples using a magnet. This work has thus showed not only a practical sensing method for Zn2+ and Hg2+, but also a promising guide to the design of fluorimetric/colorimetric sensors for other targets.
提出了一种He气辅助熔接的全光纤型空芯光子晶体光纤(HC-PCF)低压气体腔的制备方法。通过用高压待充气体冲洗HC-PCF,确保了腔内的气体纯度;通过利用光谱监测系统监测HC-PCF降压过程及He气辅助熔接过程中CO2吸收光谱的变化,研究了HC-PCF中气体动力学运动过程;通过利用He气辅助熔接方法,制备得到压强为7 k Pa、插入损耗小于2 d B、长度为10 m的全光纤型HC-PCF低压CO2气体腔。该方法也适用于更低压强的HC-PCF气体腔的研制,且制备的气体腔具有良好的气密性和长期稳定性。
实验研究了激光诱导化学沉积法(LICDM)中诱导激光功率及诱导时间对锥形光纤表面增强拉曼散射(SERS)探针性能的影响。通过优化激光诱导功率为90 m W、诱导时间为50 min,制备出高灵敏度的锥形光纤SERS探针,结合便携式拉曼光谱仪实现了1.0×10-7mol/L甲基对硫磷(MP)的检测;该方法制备的探针对MP的SERS光谱检测具有良好的重复性。这种高灵敏度、可重复性好的锥形光纤SERS探针在农残现场检测、定量分析等方面具有潜在的应用前景。
A compact and stable all-normal-dispersion mode-locked ring fiber laser with the repetition rate of 312 MHz is obtained with a wavelength-division multiplexing isolator. The compressed pulse is nearly transform-limited and the pulse width is 118 fs. It exhibits an optical efficiency of 50% and the maximum output power is about 205 mW with a 410 mW pump.
The surface topography of noble metal particles is a significant factor in tailoring surface-enhanced Raman scattering （SERS） properties. Here, we present a simple fabrication route to hexagonally arranged arrays of surface-roughened urchin- like Ag hemispheres （Ag-HSs） decorated with Ag nanoparticles （Ag-NPs） for highly active and reproducible SERS substrates. The urchin-like Ag-HS arrays are achieved by sputtering Ag onto the top surface of a highly ordered porous anodic aluminum oxide （AAO） template to form ordered arrays of smooth Ag-HSs and then by electrodepositing Ag-NPs onto the surface of each Ag-HS. Owing to the ordered arrangement of the Ag-HSs and the improved surface roughness, the urchin-like hierarchical Ag-HS arrays can provide sufficient and uniform ＂hot spots＂ for reproducible and highly active SERS effects. Using the urchin-like Ag-HS arrays as SERS substrates, 10-7 M dibutyl phthalate （a member of plasticizers family） and 1.5 × 10-5 M PCB-77 （one congener of polychlorinated biphenyl, a notorious class of pollutants） are identified, showing promising potential for these substrates in the rapid recognition of organic pollutants.
Haibin TangGuowen MengZhongbo LiChuhong ZhuZhulin HuangZhaoming WangFadi Li
