一例水溶液中识别铜离子的染料探针

通过罗丹明B与乙二胺反应生成的中间体合成了一例可以对铜离子进行比色检测的探针R-Cu.R-Cu可以实现对在HEPES(5 mmol/L;pH 7.4)溶液中Cu2+的比色可视化识别,加入Cu2+后,R-Cu的吸收明显增强,呈现出罗丹明B的紫红色.探针对Cu2+具有较高的选择性和灵敏性,对其他常见的金属离子具有较强的抗干扰能力.该探针可以在较宽的特别是近中性pH环境下有效检测Cu2+,最低检出限为2.70×10?7 mol/L.     

A novel successive demultiplexing scheme based on optical-CDMA balanced demodulation for FBG sensor systems

In order to increase the multiplexing density of the fiber Bragg gratings （FBGs） for a low cost per-sensor, based on the analysis of the spectrum shadow distortion （SSD）, a novel successive demultiplexing scheme for FBG sensors has been developed. It is based on the optical cade division multiple access （CDMA） balanced demodulation. A high-density multiplexing-demultiplexing system for FBG sensors has been designed, and corresponding simulation carried out has demonstrated that the FBG sensors＇ reflective signals can still be obtained accurately and respectively, even if FBG sensors＇ operating bandwidths heavily overlap. The SSD has been greatly mitigated.     

Pressure dependence of Brillouin frequency shift in bare silica optical fibers

The effect of hydrostatic pressure (up to 28 MPa) on Brillouin frequency shift (BFS) within two types of bare, single-mode fibers is studied via Brillouin optical time domain analysis technique. Experimental results show a negative linear relation between pressure and BFS, with almost the same sensitivity in both types of fibers. The average value of experimental slopes is -0.742 MHz/MPa. This value is found to be well suited to theoretical analysis on the basis of data on bulk silica glass in previous reports. This preliminary evaluation may result in a new method for distributed pressure sensing along silica optical fiber.