Research on fiber gas sensor system based on average filtering algorithm

数字平均滤波是信号处理中一种常用的方法。在小信号检测中,使用数字平均滤波可以获得较高的信噪比,提高检测的灵敏度。本文提出了一种利用光学器件来实现数字平均滤波的新方法,应用于基于差分吸收检测原理的窄带扫描光源光纤气体传感系统。系统的输出是一段连续的光谱,包含有被测乙炔气体的多个特征吸收峰。系统使用法珀标准具ETAlOn和参考光栅提供波长参考,完成对输出信号的光谱重建。对相同波长范围的信号进行平均滤波,使气体的相同特征吸收峰重合,提高检测的灵敏度。利用光谱重建,克服了可调谐fAbry-PErOT滤波器驱动电压和透射波长不稳定因素的影响。实验结果表明,本系统可以方便有效地实现光谱意义上的数字平均滤波,检测到较低浓度的乙炔气体,比较适用于工业化气体检测系统。Digital average filtering is a widely used signal processing method.In small signal detection,digital average filtering can obtain higher signal-to-noise ratio and can improve the detection sensitivity.This paper puts forward a new method using optical device to realize the digital average filtering.Basing on difference absorption principle,a new optical fiber gas sensor system based on a scanning light source is presented,and a novel optical gas sensor system is designed.By utilizing ETALON and reference grating,it can provide reference wavelength,and realize the spectrum reproducing of the output signal.Therefore,the same spectral signals can be superposed.This method is able to overcome the uncertainty effect caused by the transmission wavelength of tunable Fabry-Perot filter and filter′s driving voltage.Experimental results show that the gas detection sensitivity is remarkably improved and can detect fairy low concentration acetylene gas.The system is suitable for industrial gas monitoring.国家自然科学基金项目(No.61077031);厦门大学“985”与“211”工程项目资

Isolation and Characterization of a H2 -producing Strain Enterbacter sakazakii HP

通讯作者 Tel 0592-2185731, E-mail： longmn@ xmu.edu.cn[中文文摘]在自然环境中分离到一株具有高产氢活性的微生物菌株,经细菌鉴定仪及16S rRNA基因序列分析,鉴定该菌株为Enterbacter sakazakii HP。分析了起始pH值、反应温度、碳源、起始糖浓度、起始氧浓度及菌体密度等因素对菌株产氢活性的影响。研究表明,该菌株发酵产氢较适合的条件为:以葡萄糖为产氢底物,起始pH值8.0,菌体密度OD600=0.7,反应温度35℃,糖浓度为0.1mol/L,氧浓度为0%的条件下,此时产氢菌株的最高产氢活性为5.34μmolH2/h.mgdw,氢的得率为1.94molH2/mol葡萄糖。[英文文摘]A H2 -producing bacterial strain was newly isolated and identified as Enterbacte sakazakii HP by 16S rDNA sequence analysis and detection by BBLCRYSTAL AUTOREADER.Various factors,including substrates and its concentration,initial pH,temperature and oxygen,on the hydrogen production of E.sakazakii HP have been studied extensively.Among several sugars,glucose was the favorite substrate for hydrogen production.The optimum condition for hydrogen production by Enterbacte sakazakii HP was achieved as:initial pH8.0,cell density OD600 =0.7,temperature 35℃,glucose concentration 0.1 mol/L,oxygen concentration 0%.Under batch fermentative hydrogen production conditions,the maximal hydrogen production activity and hydrogen yield were obtained as 5.34μmol H2 /h·mg dw and 1.94mol H2 /mol glucose,respectively.The research results suggest that Enterbacter sakazakii HP is an ideal candidater for biological hydrogen production.国家自然科学基金项目(No30470395);厦门市科技项目(No3502Z20041070);厦门大学新世纪优秀人才计划项目;福建省青年科技人才创新项目(No2005J003

Study on the Distributions of Lead and Cadmium in Rats by ICP-MS with Stable Isotope Tracer

采用稳定同位素示踪技术研究重金属元素铅、镉在大鼠体内的分布,通过对大鼠进行浓缩同位素206Pb、112Cd灌喂,解剖取其肝、肾、睾丸和心脏等脏器,通过相应的化学处理,用电感耦合等离子体质谱(ICP-MS)测量铅、镉元素在各个脏器中的含量及其同位素组成变化。根据同位素比值的变化研究Pb、Cd在各脏器中的分布、蓄积规律和各脏器对引入的浓缩同位素利用率。结果发现:重金属Pb和Cd蓄积的最主要场所是肝和肾,其次是睾丸和心脏,而在脑中的积累最少。在肝和肾中Cd的同位素利用率为0.0488%、0.0154%,Pb的同位素利用率为0.0101%、0.0078%,远高于其它脏器。与传统的方法相比较,该法具有更接近慢性中毒、危害性小,能将重金属来源分为天然来源和人为引入等特点。The distributions of lead and cadmium in rats were studied using stable isotope tracer technique.The rats were fed with enriched stable isotope 206Pb and 112Cd,then the liver,kidney,testicle and heart were eviscerated.After chemical treatment,the contents of lead and cadmium and their isotope ratios in each viscera were determined by ICP-MS.Experimental results showed that lead and cadmium accumulated mostly in liver and kidney,next in testicle and heart,and least in brain.The utilization rates of cadmium and lead isotopes in liver were 0.048 8% and 0.010 1%,respectively,and in kidney 0.015 4% and 0.007 8%,respectively.Compared with the traditional methods,the present method can differentiate the origins of lead and cadmium.福建省重大科技项目资助课题(2003Y005-04,2003Y003

An Algorithm of Filtering Background Noise of Optical Fiber Gas Sensor

在光纤气体传感系统中,为提高检测的灵敏度,需要采取措施抑制系统的各类噪声。通过设计低噪声的前置放大器和光源驱动电路可有效地降低系统的噪声;但对于因光路变化和光在传输过程中偏振态发生变化引起的背景噪声的处理一直是光纤气体传感系统测量灵敏度提高的难点。提出一种基于最小二乘拟合的背景噪声滤除算法。利用参考光栅和法布里-珀罗标准具实现对输出信号的光谱重建。在此基础上,利用气体特征吸收峰两边的输出拟合整个输出曲线。将系统的输出与拟合曲线相除,实现系统输出的归一化,有效地滤除了系统的背景噪声,避免了当传感系统背景噪声发生变化时,需要重新采集背景气的繁琐工作,为测量带来方便。In fiber gas sensor systems,in order to improve the detection sensitivity,it is vitally necessary to make intensive efforts to restrain various noises of the system.Designing low-noise preamplifier and light driving circuit can effectively reduce the system noise,but cannot reduce the noise caused by the changes of optical path.This kind of noise is called background noise,which influences the measuring sensitivity of fiber gas sensor system.Therefore,how to filter the background noise affects the improvement of measurement accuracy.This paper puts forward a method based on least logarithm square method which can easily reduce the background noise of optical gas sensor system.By using reference grating and Fabry-Perot etalon,it can reconstruct the output spectra.A modified least square method is used to fit the envelope of gas absorption lines by using the data of absorption peaks on both sides.Dividing the gas absorption lines by the envelope line of absorption lines,the normalization of output is realized and thus the drift of the background noise curve due to the change of experimental environment can be reduced.This method can avoid data collection again when the background noise is drifting,and brings convenience to measurement.国家自然科学基金(61077031);厦门大学985和211工程资助课

Biohydrogen Production from Rice Straw by Simultaneous Saccharification and Fermentation Using Klebsiella oxytoca HP1

氢作为一种清洁的能源引起了人们的普遍重视.实验以产酸克雷伯氏菌(Klebsiella oxytoca)HP1为产氢菌株,以稻草粉为产氢底物,进行同步糖化发酵(Simultaneous Saccharification and Fermentation,SSF)产氢.对影响同步糖化发酵产氢的单因子进行试验,选取对氢产率影响较大的因子:温度、pH、纤维素酶用量等进行L9(34)正交试验.结果表明同步糖化发酵产氢的最佳条件为:温度40℃,pH6.5,纤维素酶用量为20FPAU/g稻草粉,摇床转速100r/min,发酵时间42h.在该条件下的最大氢产率为110.6mL/g稻草粉,稻草粉的氢转化率为22%.进行了10L放大发酵产氢试验,最大氢产率为122.3mL/g稻草粉,氢转化率为24.3%.与分步糖化发酵(Separate Hydrolysis and Fermentation,SHF)产氢相比,氢产率提高34.4%.研究表明,利用同步糖化发酵工艺可以提高生物制氢的产量和得率.Being regarded as a clean energy source,biological hydrogen attracts more and more attention.Hydrogen production from rice straw by simultaneous saccharification and fermentation (SSF) was studied using the Klebsiella oxytoca HP1 in this report.The experiments of batch ferment hydrogen production were carried out in 600 mL serum bottles.Single factor and orthogonal experiments showed that the optimal conditions for hydrogen production were:pH6.5,ferment temperature 40℃,cellulose dose 20 FPAU/g rice straw,revolution 100 r/min and ferment time 42 h.The maximum H2 production (110.6 mL/g rice straw) and H2 yield efficiency (22%) were obtained under the above conditions.The enlarge experiments were carried out in a 10 L bioreactor,a maximum H2 production of 122.3 mL/g rice straw and a H2 yield efficiency of 24.3% were achieved.The H2 production increased by 34.4% compared with the separate hydrolysis and fermentation hydrogen production.This research indicated a perfect application of SSF in biohydrogen production from cellulose material.国家自然科学基金项目(30470395);; 厦门市科技项目(3502Z20041070);; 厦门大学新世纪优秀人才计划项目(X07114)资

甘草粗提物对鲫的抗应激及免疫保护功效研究

采用腹腔注射和混饲投喂两种方式研究中药甘草(Glycyrrhiza uralensis Fiseh)粗提物对鲫(Carassius auratus)的抗应激和免疫保护功效。将一部分粗提物按0.5%和2%的质量分数制成药饵投喂实验鲫,分别在第14 d、28 d、35 d、42 d、56 d采集血样;将另一部分粗提物用无菌生理盐水按0.5%和2%的浓度配成针剂腹腔注射鲫,分别在第3 d、7 d、14 d、21 d、28 d采集血样。结果显示:投喂实验中药物组和对照组血清皮质醇水平均呈先升后降趋势,除第14

INVESTIGATION of ADSORPTION,DISTRIBUTION AND MIGRATION of LEAD BETWEEN ENVIRONMENT AND PLANT BY STABLE LEAD ISOTOPIC TRACER

以低浓度的稳定铅同位素为示踪剂,采用电感耦合等离子质谱法,通过盆栽实验,考察了在不同的PH值环境和不同铅源引入方式下,茶树植株对铅的吸收情况以及铅在植株体内的分布及迁移规律.结果表明:茶树植株对大气铅源污染的反应比土壤铅源污染灵敏;大气铅源污染有往顶端(芽)迁移的趋势,而土壤铅源污染则主要聚集在根部;低PH条件增强植株对铅的吸收且能促使植株体内的铅的往高处迁移.本实验方法危害小,更接近植株承受低浓度污染的实际情况,能区分实验引入铅源和环境引入铅源.Low concentration isotopic lead tracer(SRM982)was adopted,ICP-MS was used as a detection tool.By pot test,the chemical action of lead in tea under the condition of different pH and different modes of lead exposure was studied.Simulated rain water(CPb=0.5mg·l-1) was used to pot soil and spray leaf to investigate the adsorption,distribution and migration of lead in two systerms:atmosphere-tea and soil-tea.The results are:1.the reaction to lead pollution from atmosphere is more sensitive than that from soil;2.the migration and distribution in tea of lead pollution from atmosphere and from soil is different,the former has the trend of conveying to bud while the latter focus mainly in root;3.pH has an evidently effect on the migration of lead in tea,generally,low pH facilitates migration to upper parts.This method has the advantages that tea beared low polution,and the hazard to plant is less than traditional ways.In addition,lead from environment and from tracer can be separated.国家“863”计划(2007AA09Z115)资

Study on CA speciation in different tissues of rats by stable isotope tracer with SEC-ICP-MS

通过建立凝胶排阻色谱分离紫外与电感耦合等离子体质谱在线检测的联用技术,研究了灌喂低浓度镉富集同位素后大鼠各器官中镉与蛋白结合的形态。结果发现,镉主要在肝、肾、睾丸中与硫蛋白结合形成金属硫蛋白。与传统方法相比,该法危害性小、具有更接近慢性中毒、能将重金属来源分为天然来源和人为引入等特点。The experiment aims to study combination of Cd and proteins in different tissues of rat fed with Cd isotope by SEC-UV-ICP-MS.In testicle,liver and kidney,Cd-MTs were found to be the binding product of Cd and MTs.This method is much more accurate,humanl than traditional method,and be able to distinguish the heavy metal from nature and artificiality.福建省重大科技(2003Y005-04)和(2003Y003)项目资

甘草粗提物对鲫的免疫调节作用

本研究对中药甘草(Glycyrrhiza uralensis Fiseh)进行了粗提,将粗提物按0.5%和2%的质量分数制成药饵投喂鲫鱼(Carassius auratus)后,于第14天、28天、35天、42天5、6天采样检测其免疫指标。结果显示,低剂量组试验鱼血清溶菌酶活性逐渐升高,高剂量组在35d达到最大值(205.5±28.8)U/mL,之后略有下降。低剂量组和高剂量组试验鱼血清杀菌活性均有所波动,波动范围分别为62.0%—73.1%和75.0%—83.3%,就各期而言,对照组、低剂量组和高剂量