基于D型光纤Bragg光栅的加速度传感器

本文介绍了一种新型的基于d型光纤brAgg光栅(d-fbg)测量加速度信号的方案,并对测量系统进行了理论分析和实验测量。该加速度传感器具有尺寸小、质量轻、结构简单、灵敏度高等优点,可用于测量低频振动(0.1Hz数量级)和小幅值的加速度信号。试验数据表明基于该方案的测量灵敏度可达到563.67με/g,最小分辨力为1.15x10-3g

Tunable narrow linewidth fiber laser with two FBG-FPs

基于游标原理,利用一对自由谱宽(fSr)略有不同的光纤布喇格光栅法布里-珀罗腔(fbg-fP)作为模式选择器件,设计了一种新颖的环形腔光纤激光器。从理论和实验上研究了该激光器的特性。通过对可调谐fbg-fP应力调谐,在1552.240~1552.912 nM范围内,以96 PM为平均间距,获得了8个由固定fbg-fP的透射谱所确定的窄线宽稳定激光输出。8个输出波长的平均功率为-17.66 dbM,波动在0.7 db范围内。当泵浦光的功率为95 MW的时候,输出信号的信噪比均大于50 db。实验上每隔1 MIn用光谱分析仪(OSA)对输出光波长自动扫描,记录的输出光波长漂移在数皮米范围内,且功率的波动小于0.1 db。这种可调谐的窄线宽光纤激光器在光纤通信和光纤传感方面有潜在的应用价值。Using a pair of Fiber Bragg grating Fabry-Pérots(FBG-FP)with a little different FSR as its wavelength-selective components,a novel ring laser based on the vernier effect is proposed.We have studied the characteristics of this kind of tunable fiber laser both theoretically and experimentally,and obtained 8 discretely tunable laser wavelengths ranging from 1552.240 nm to 1552.912 nm with an average 96 pm span by pulling the tunable FBG-FP.The output spectrum peak is uniform among different wavelength at-17.66 dBm with a fluctuation of 0.7 dB.When the pump power is 95 mW,the signal-to-noise ratio is better than 50 dB.The output spectrum of the laser is recorded automatically by an optical spectrum analyzer(OSA)once a minute.It is found that the output wavelength drift within a few pico-meter and the fluctuation of the output power is less than 0.1 dB.This kind of fiber ring laser may have potential applications in optical communications and sensors.国家自然科学基金项目(No.61077031/F050208); 福建省教育厅B类科技研究项目(No.JB11097)资

一株高效抑藻放线菌的分离筛选及鉴定

从福建云霄国家红树林自然保护区滩涂沉积物样品中,共分离获得521株纯培养物.通过检测球形棕囊藻(Pha-eocystis globosa)荧光强度计算抑藻率,从521株菌中筛选到27株具有抑藻活性的菌株.在27株抑藻菌中,菌株O3-26对球形棕囊藻具有最高的抑藻率(高达96.71%).菌株O3-26的抑藻谱实验显示,该菌株抑藻活性表现出一定的种属特异性,对硅藻门(Bacillariophyta)的三角褐指藻(Phaeodactylum tricornutum)和中肋骨条藻(Skeletonema costatum)2株测试藻株没有抑制作用,而对绿藻门(Chlorophyta)盐生杜氏藻(Dunaliella salina)和自养小球藻(Chlorella autotrophi-ca)2株藻株具有较强抑藻作用.扫描电镜观察显示,该菌株孢子丝直至螺旋状且孢子表面带刺.生理生化实验显示,该菌株在所得到的大多数培养基上生长良好,在营养琼脂培养基中可以产生水溶性色素;不能在棉子糖作为唯一碳源的培养基上生长.16SrRNA基因相似性分析表明,菌株O3-26属于链霉菌属(Streptomyces),并与灭癌素链霉菌(Streptomycesgancidicus)15412菌株具有最高的同源性(99%).生理生化实验表明,二者之间生理特征存在一定差异.综合形态特征、生理特征以及系统发育分析的结果,鉴定该菌株为灭癌素链霉菌

Expression and Anti-tumor Activity of Apo-allophycocyanin in Spirulina

目的对螺旋藻脱辅基异藻蓝蛋白(apo-APC)的原核表达、蛋白纯化和抗肿瘤活性进行研究。方法通过基因工程技术,将异藻蓝蛋白基因(apc)克隆至pET28(a),转化JM109(DE3),构建其原核表达载体,并实现apo-APC蛋白在工程菌中高效表达;采用金属离子螯合亲和层析纯化目的蛋白,凝胶电泳分析其纯度,Western blot鉴定;以S180荷瘤小鼠为动物模型,分析apoAPC的抗肿瘤活性。结果通过基因工程技术获得apo-APC蛋白;动物实验显示apo-APC可抑制荷瘤小鼠体内S180肉瘤的生长,升高荷瘤小鼠的白细胞数量。结论螺旋藻藻胆蛋白的抗肿瘤活性至少有部分来自于其脱辅基蛋白

data privacy protection mechanism for cloud storage based on data partition and classification

云存储系统数据管理权和所有权的分离导致数据安全和隐私保护难题。传统的基于单纯加密技术的云存储数据隐私保障机制在实际的数据操作过程中带来了较大的系统开销。为了以低开销实现云存储系统中异地托管数据的隐私保护机制,提出了一种基于数据分割与分级的云存储数据隐私保护机制。机制首先将数据合理分割为大小数据块;再分别将小块数据和大块数据部署在本地和异地;然后按数据不同的安全级别需求,联合采用数据染色和不同强度的数据加密技术进行数据染色或加密,以在保护云存储用户数据隐私的同时,提高灵活性,降低系统开销。国家自然科学基金(61202004,61272084)|国家教育部高等学校博士学科点专项科研基金(20093223120001,20113223110003)|中国博士后科学基金(2011M500095)|江苏省自然科学基金(BK2011754,BK2009426)|江苏省博士后科研项目(1102103C)|江苏省高校自然科学研究计划(12KJB520007)|江苏省科技支撑计划(BE2009158)|信息安全国家重点实验室开放课题(03-01-1)资

Measurement of the Linewidth of DFB Fibre Laser Based on the Delayed Self-homodyne

DFB单频光纤激光器输出的超窄线宽作为光学系统中的一个重要参数需要进行准确的测定,因此,采用延时零拍法重点对1053 nm波长的DFB掺Yb3+光纤激光器的超窄线宽进行了测量,并且研究了差拍光电流谱线的输出特性.针对超窄线宽DFB光纤激光器输出的特点设计了相应的光电转换放大电路,测得1053 nm的DFB光纤激光器的线宽为31 kHz.该测量结果对于窄线宽DFB光纤激光器应用于光纤传感、光纤通信领域具有一定的指导意义.As an important parameter in the laser system,the narrow linewidth of DFB fibre laser must be measured accurately.Therefore,the linewidth of a Yb3+ doped DFB fibre laser was measured with the delayed self-homodyne detection method in the present work.Meanwhile the characteristics of the frequency spectrum of the laser beat signal was studied,and the sensitivity,stability and frequency responsivity of the signal detection circuit used in the experiment were analyzed.The measured linewidth of the 1 053 nm DFB fiber laser is of 31 kHz,in agreement with the theoretical analysis.Furthermore,the results based on the delayed self-homodyne method are valuable for applications of DFB fibre laser in the field of optical fibre sensor and optical communication.福建省自然科学基金(A0010004)资

Theoretical and Experimental Investigation of the Bending Sensitivity of the D-shaped Fiber Bragg Gratings

用材料力学理论分析了D形光纤Bragg光栅(D-shaped fiber Bragg grating,D-FBG)以及常规光纤Bragg光栅由弯曲引起的轴向应变,得到了光栅Bragg波长漂移的弯曲敏感特性.实验结果和理论计算结果基本相符.与常规FBG相比,该D-FBG的弯曲灵敏度要高近80倍.因此D-FBG可以直接应用于弯曲形变的测量,以及间接应用于压力、加速度等物理量的测量.理论分析和实验结果对采用该类型光纤光栅的器件和传感系统的设计具有参考意义.The axial strain of D-shaped fiber Bragg grating(D-FBG) and normal fiber Bragg grating induced by bending was analyzed with mechanics of materials.Bending sensitivity characteristic of Bragg wavelength′s shift was obtained.Experiment result was in good agreement with the theory analysis.D-FBG′s bending sensitivity was about 80 times higher than normal circularly symmetrical FBG.The studied D-FBG can be directly applied in bending measurement,and indirectly in pressure or acceleration measurement.The theory analysis and experiment result was helpful for the design of device or sensor system using D-FBG.国家自然科学基金(60177026);; 福建省自然科学基金(0012-K32008)资

一种溶解MAX相陶瓷材料的方法

本发明提供了一种溶解MAX相陶瓷材料的方法。该方法将MAX相陶瓷材料作为阳极，惰性电极或者耐电解液腐蚀电极作为阴极，电解液选用氢氟酸溶液，进行通电电解，电解过程中MAX相陶瓷材料失去电子成为离子形态进入电解液，实现了MAX相陶瓷材料的溶解。该方法简单易行、安全可控，当MAX相陶瓷作为包壳材料时还可以用于实现芯壳分离，因此在核能系统乏燃料处理等技术领域具有良好的应用前景

Photonic Generation of Microwave Signals

文章对现有通过光子学技术生成微波信号的方法作了简要的综述,并介绍了我们提出的一种利用激光拍频产生可调谐微波信号的新方法。这种方法基于光纤光栅法珀滤波器与光纤环形腔激光器技术,产生波长间隔可调谐的双波长单纵模激光,使用高速光电探测器对双波长激光进行拍频,生成频率可调的微波信号。实验上获得了频率为9.4885～10.0712GHz的微波信号。文中所提出的方法在无线接入网,无线传感网,射频信号光纤传输,软件无线电等方面有应用前景。In this letter,the present techniques for photonic generation of microwave signals are summarized,and a novel method for generating frequency-tunable microwave signals is proposed.The techniques of thefiber Bragg gratings based Fabry-Perot filter and the optical fiber ring laser are adopted to generate the dual-wavelength single-longitudinal-mode lasings with tunable wavelength- spacing.Then the frequency-tunable microwave signals can be generated by beating the dual-wavelength lasings with a high-speed photodetector.A series of microwave signals with frequency from 9.4885 GHz to 10.0712 GHz are realized experimentally.This proposed technique will have potential applications in wireless access networks,wireless sensing networks,ROF systems,software defined radio,and so on

EFFECTS OF MICROSTRUCTURE AND STRESS RATIO ON HIGH-CYCLE AND VERY-HIGH-CYCLE FATIGUE BEHAVIOR OF Ti-6A1-4V ALLOY

采用旋转弯曲和超声疲劳实验分别测试了全等轴和等轴双态组织Ti-6A1-4V合金的高周和超高周疲劳性能,并用SEM观察了疲劳断口特征.结果表明:2种组织T1-6A1-4V合金的高周和超高周疲劳行为相似,不同应力比下,其S-N曲线均表现出单线形或双线形的形式;存在滑移机制和解理机制2种疲劳破坏机制.随应力比增加,2种组织Ti-6A1-4V合金的高周和超高周疲劳破坏机制均从滑移机制向解理机制转变.基于疲劳寿命和疲劳强度建立模型分析了应力比对2种机制之间竞争行为的影响,模型预测结果与实验结果趋势吻合.</p