Highly soluble perylene dyes: Synthesis, photophysical and electrochemical characterizations

Highly soluble perylene diimide derivatives with symmetrical and unsymmetrical secondary, tertiary alkyl side chains were synthesized and their photophysical properties, redox potentials and thermal stabilities were measured and compared with previously reported 1-pentylhexyl substituted swallow-tailed perylene diimide. Diasteroisomers of the novel, unsymmetrical swallow-tailed substituted perylene diimide compound could not be detected using low temperature NMR spectroscopy. The novel dyes were soluble in a range of organic solvents indicating potential for photo-electronic applications and photocatalytic reactions. Two dyes were not only soluble in organic solvents but also showed solubility in aqueous media as the hydrochloride salt, thus offering potential use in biological applications.     

示波器探头种类及其工作原理

介绍了示波器探头的种类及其工作原理,主要从探头的负载效应、探头的补偿、探头的接地引线电感等方面论述了示波器探头在测量过程中对被测信号的影响和注意的一些问题.     

Optical sensing of materials movements occurring at a plant surface with a probe beam

Optical sensing of materials movements across a plant surface with a probe beam is reported. It is based on monitoring of deflection of a probe beam passing through a vicinity of the plant surface. The deflection of the probe beam was caused by concentration gradients of chemical species involved in the materials moments in physiological activities of the plant. Typha angustifolia L. was used as a model plant. The beam deflection at different locations of both leaves and roots in respiration process were monitored and compared. It is found that deflection signals changed with time and locations. Experimental results showed that the beam deflection method could be used for noninvasive sensing and monitoring of materials movements across the plant surface.     

Synthesis and photophysical properties of structural isomers of novel 2,10-disubstituted benzofuro[2,3-e]naphthoxazole-type fluorescent dyes

Structural isomers of novel 2,10-disubstituted benzofuro[2,3-e]naphthoxazole fluorescent dyes have been synthesized. The phtophysical properties have been investigated in solution and in the solid state. The absorption and fluorescence intensities of the naphth[1,2-d]oxazoles are much stronger than those of the naphth[2,1-d]oxazoles in solution. Moreover, in the solid state, the emission intensities of the former are typically much stronger than those of latter isomers. To understand the differences in photophysical properties, semi-empirical molecular orbital calculations and the X-ray crystallographic analyses have been performed.     

Flying Probe Tester : Architecture, Principle and Implementation

1 IntroductionThere are mainly three kinds of circuit faults:components' fault, PCB' s (Printed Circuit Board)fault and assemblage fault. Among them, PCB' s faultaccounts for half of all. Generally speaking, PCB' sfault comes into being in the manufacturing process andthe most common forms of the fault include the short ofconductors in different nets and the open of conductorsin the same net. There will be economy loss if we solderthe electron components on a PCB with fault. So, it isve…     

All-fiber Based Er^3＋∶Yb^3＋ Co-doped Fiber Laser

An all-fiber based Er^3＋ ：Yb^3＋ co-doped double clad fiber laser operating at 1 550 nm is demonstrated. By using 9 m long Er^3＋ ： Yb^3＋ co-doped fiber（EYDF） as the gain medium, and using a pair of fiber Bragg gratings as wavelength filters, the line-width of the output laser is as narrow as 0.2 nm and the output power is more than 6 mW. The fluorescent effect of the laser before its emission is also studied. And it is found that the Er^3＋ ： Yb^3＋ co-doped double-clad fiber laser also exhibits a high gain for Yb^3＋ transition near 1 080 nm.     

荧光灯与电子镇流器的最佳匹配

荧光灯在电子镇流器高频状态下的工作机理及工作特性和电感镇流器５０Ｈｚ工作状态下有很大区别，本文通过试验和理论分析，就紧凑型荧光灯在电子镇流器工作状态下的波峰系数，工作电流，工作电压，光通量，光效等光电参数进行讨论，提出了最佳匹配参数。     

A high efficiency single molecule localisation algorithm with sub-pixel resolution based on fluorescence images

We introduce a technique of fast single molecule localisation including image de-noising and Gaussian mask sub-pixel refinement (IDGM) with the characteristics of simplicity, great computational efficiency as well as high accuracy and precision. The image de-noising corrects images suffering from background and shot noise, and the Gaussian mask is used to derive the centres of single molecules with sub-pixel resolution. We quantitatively evaluate the performance of IDGM compared to two-dimensional direct Gaussian fitting (2DDGF) on 1000 simulated images at variable signal-to-noise ratios (SNRs), where the single molecule diffraction spot is simulated as a point spread function distribution. It is shown that IDGM performs better than 2DDGF in terms of accuracy and precision for all tested SNRs. In addition, the execution time is shorted by one order of magnitude, making the IDGM algorithm suitable for localising single molecules especially for on-line or time-critical applications.