多通道光纤可燃气体监测系统的研究

采用可调谐激光吸收光谱(TDLAS)技术和光分路技术,实现了多通道光纤可燃气体监测系统 的 研制。系统中,监测仪部分采用分离式设计,无源传感探头和有源仪表之间通过光纤连接, 含有浓度信息的光信号通过光纤传输到仪表进行处理。传感探头仅由气室和光纤组成,不带 有任何电路,可以保证探头的本质安全性和抗电磁干扰能力。设计了乘法解调电路,以解决 光纤传输产生的相位延时,而导致测量结果偏差的问题。测试结果表明,本文系统能够实现 现场非电、远程、长期在线和分布式气体浓度监测预警预报,且检测结果不受光纤 长度变化的影响,在工业标准的100最低爆炸极限(LEL)测量范围内能 够正确检测CH₄气体浓度值,检测灵敏度为0.1LEL。     

Machine cell formation in generalized group technology

In this paper, we study the configuration of machine cells in the presence of alternative routings for part types. The objective function is the minimization of transportation costs. Limits on cell sizes as well as separation constraints (i.e. machines that are not allowed to be placed in the same cell) and co-location constraints (i.e. machines that must be placed in the same cell) may be imposed. An efficient Tabu Search (TS) algorithm is proposed to solve this problem. Extensive computational experiences with large-size problems show that this method outperforms some existing Simulated Annealing (SA) approaches.     

抗干扰的光纤光栅边缘滤波解调技术研究

针对传统的光纤光栅边缘滤波解调系统中需使用双光功率计接收信号,而光功率计各自噪声的随机性,导致光功率计的噪声干扰无法消除的问题,利用光开关在光电接收处只使用单光功率计,达到解调并消除噪声干扰的目的,最终提高光纤光栅边缘滤波解调技术的抗噪声干扰能力。将该改进应用到悬臂梁拉力测试实验中,抗噪声干扰效果显著,可以避免使用复杂的波长解调设备,结构简单,有望在工程实践中获得实际应用。     

基于聚类SURF特征的商品识别算法*

图像存在遮挡、尺度缩放、多干扰时,传统加速鲁棒特征(SURF)算法会产生错误匹配问题,提出一种基于匹配角度聚类的匹配算法。算法先提取SURF特征点,利用特征点的主方向信息进行图像角度矫正,再统计并聚类粗匹配对的匹配角度信息,依据类中元素数目和类簇数目进行两级筛选,剔除异常角度信息的误匹配对。本文算法与随机抽样一致性算法(RANSAC)进行实验对比,表明该算法能有效提高匹配正确率和保证低误剔除率,提高了商品图像的识别率。     

The Physical and Antimicrobial Properties of Silver Doped Hydroxyapatite Sintered by Microwave and Conventional Sintering

In this paper, the silver-doped hydroxyapatite (AgHAp) nanoparticles were successfully synthesized by conventional and microwave sintering. The structural and antibacterial properties of AgHAp without heat treatment (AgHAp-90) and after heat treated at 800 and 1000?°C by conventional (AgHAp-800CS, AgHAp-1000CS) and microwave sintering (AgHAp-800MS, AgHAp-1000MS) were discussed respectively. The results of X-ray diffraction and fourier transform infrared spectroscopy suggested that the pure phase of AgHAp nanoparticles were obtained at 800?°C, but the β-TCP phase was observed when the temperature up to 1000?°C. Scanning electron microscopy images showed that the morphology and size of the nanoparticles changed with the improvement of temperature. The energy dispersive X-ray analysis identified the existence of Ag, Ca, P. The antibacterial test of AgHAp showed the excellent antimicrobial activity against gram-negative strains Escherichia coli and gram-positive strains Staphylococcus aureus. Also, the results showed the AgHAp had a smaller effect on gram-positive strains compare with gram-negative strains, and the antimicrobial activity of particles sintered by microwave was better than samples sintered by conventional. It showed the great advantages of microwave sintering. The silver ion releasing in solution was measured by the inductively coupled plasma and elucidated the results of antibacterial tests.     

Enhancing Heterogeneous Catalytic Activity of Iron （Ⅱ） Phthaloeyanine by Ethanol and Its Application in 2,4-diehlorophenol Detection

A chemical system for facile and accurate detection of 2,4-dichlorophenol(DCP) via iron(II) phthalocyanine(Fe(II)Pc) catalyzed chromogenic reaction is reported for the fi rst time. In this system, DCP could be oxidized by dioxygen with the catalysis of Fe(II)Pc and then coupled with 4-aminoantipyrine(4-AAP) to generate pink antipyrilquinoneimine dye. Control experiments showed that the addition of ethanol could obviously enhance the catalytic activity of heterogeneous Fe(II)Pc catalysts because of the partial dissolution of Fe(II)Pc nanocubes, which was confirmed by the SEM analysis. On the basis of the detection results of DCP in the range from 2×10-5 to 9×10-4 mol/L, we obtained a regression equation(A = 0.187 5 + 0.01 209C(R2=0.995 6)) with the detection limit(3σ) of 3.26×10-6 mol/L, which could be successfully used in detecting the real samples.     

双折射下啁啾光栅径向局部受压特性研究

采用光学分析和实验相结合的方法,分析了啁啾光纤布拉格光栅(CFBG)径向局部受压时的双折射现象、啁啾光栅径向局部受压时的光谱变化以及双折射对径向局部受压啁啾光栅光谱的影响。对所观察到光谱响应的突出特点进行了定性解释,以获得对光栅局部受压特性的真实洞悉。结果表明:受压处反射谱的下沉幅度随着受压载荷的增加而增大。实验结果与理论分析一致。     

Preparation of magnetic chitosan nanoparticles and immobilization of laccase

The magnetic chitosan nanoparticles were prepared by reversed-phase suspension method using Span-80 as an emulsifier, glutaraldehyde as cross-linking reagent. And the nanoparticles were characterized by TEM, FT-IR and hysteresis loop. The results show that the nanoparticles are spherical and almost superparamagnetic. The laccase was immobilized on nanoparticles by adsorption and subsequently by cross-linking with glutaraldehyde. The immobilization conditions and characterizations of the immobilized laccase were investigated. The optimal immobilization conditions were as follows: 10 mL of phosphate buffer (0.1 M, pH 7.0) containing 50 mg of magnetic chitosan nanoparticles, 1.0 mg · mL⁻1 of laccase and 1% (v/v) glutaraldehyde, immobilization temperature of 4°C and immobilization time of 4 h. The immobilized laccase exhibited an appreciable catalytic capability (480 units · g⁻¹ support) and had good storage stability and operation stability. The K _m of immobilized and free laccase for ABTS were 140.6 and 31.1 μM in phosphate buffer (0.1 M, pH 3.0) at 37 °C, respectively. The immobilized laccase is a good candidate for the research and development of biosensors based on laccase catalysis. Funded by Key Project of National Science Foundation of China (No. 60537050) and the National Science Foundation of China (No. 60377032)     

Synthesis and optical properties of MgO-doped ZnO microtubes using microwave heating

The Zn_1−xMg_xO (x = 0%, 2% and 5%) microtubes have been successfully synthesized via a microwave heating method. The as synthesized microtubes were carefully investigated. Field emission scanning electron microscope (FE-SEM) showed that all the microtubes exhibit an exact hexagonal hollow structure with smooth surfaces and straight characteristics throughout their whole lengths. UV–Vis measurement indicates that the absorption peak for ZnO microtube was shifted from 378.88 nm (3.27 eV) to 369.91 nm (3.35 eV) for Zn_0.95Mg_0.05O microtube. Room temperature photoluminescence (PL) spectra showed that the intensity of UV emission peak decreased with increase of MgO concentration and the visible emission band showed a blue shift from 538.06812 nm for ZnO microtube to 529.54114 nm for Zn_0.95Mg_0.05O microtube. Energy-dispersive spectrometer (EDS) analysis revealed the presence of Zn and O as the only elementary components with the absence of MgO as a doping material.