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1.
An investigation of the properties ofa LiNbO3 photoelastic waveguide via the acceleration-induced effect is presented.A novel three-component hybrid-integrated optical accelerometer based on a Mach-Zehnder interferometer with a LiNbO3 photoelastic waveguide has been designed, which is capable of detecting seismic acceleration in high-accuracy seismic exploration.The Mach-Zehnder interferometer was successfully fabricated and a lighting test used to check its quality. The frequency response characteristic of the accelerometer was measured. The accelerometer with a resonant frequency of 3549 Hz was demonstrated to show good linear frequency responding characteristics in the range of 100-3000 Hz. The accelerometer also shows good stability and consistency. Experimental results indicate that the outputs of the on- and cross-axis are 147 and 21.3 mV, respectively.  相似文献   

2.
An investigation of the properties ofa LiNbO3 photoelastic waveguide via the acceleration-induced effect is presented. A novel three-component hybrid-integrated optical accelerometer based on a Mach-Zehnder interferometer with a LiNbO3 photoelastic waveguide has been designed, which is capable of detecting seismic acceleration in high-accuracy seismic exploration. The Mach-Zehnder interferometer was successfully fabricated and a lighting test used to check its quality. The frequency response characteristic of the accelerometer was measured2 The accelerometer with a resonant frequency of 3549 Hz was demonstrated to show good linear frequency responding characteristics in the range of 100-3000 Hz. The accelerometer also shows good stability and consistency. Experimental results indicate that the outputs of the on- and cross-axis are 147 and 21.3 mV, respectively.  相似文献   

3.
A temperature sensor is demonstrated and fabricated by coating the single-mode tapered optical fiber with temperature-sensitive silicone rubber. It works on the change of the evanescent fields in the tapered optical fiber. Small changes in the refractive index of coating film greatly influence the power of evanescent fields, which modulate the transmission optical power in the waist region. The range of temperature measured is from 20°C to 70°C. The results show that the temperature sensor has high temperat...  相似文献   

4.
三维地质力学模型试验中光纤传感器的应用研究   总被引:1,自引:0,他引:1  
近年来,在地下结构三维地质力学模型试验的研究中。多项新技术得到应用和开发,其中也包括采用光纤传感器量测模型材料中的应变和变形,这使模型试验上了一个新台阶。采用光纤传感器量测。对于地质力学模型试验来说还是一项新技术。该文结合在一个大比尺的地质力学模型试验中采用光纤传感器的经验,对它的实际应用及埋设方法做了进一步的探讨和设想。  相似文献   

5.
郭琼  马璟 《实验技术与管理》2011,28(8):166-168,208
基于无线传感技术,在专业原有过程控制实训室的基础上设计了一套采用传感网实现的流体测控实训系统.该实训系统不仅将传感技术、通信技术、嵌入式技术及控制技术融于一体,而且还引入了虚拟仪器技术.整个系统结构清晰、扩展灵活,有助于大学生了解现代传感技术及其在流体测控领域中的应用.  相似文献   

6.
7.
Among complex network models, the hierarchical network model is the one most close to such real networks as world trade web, metabolic network, WWW, actor network, and so on. It has not only the property of power-law degree distribution, but also the scaling clustering coefficient property which Barabási-Albert (BA) model does not have. BA model is a model of network growth based on growth and preferential attachment, showing the scale-free degree distribution property. In this paper, we study the evolution of cooperation on a hierarchical network model, adopting the prisoner's dilemma (PD) game and snowdrift game (SG) as metaphors of the interplay between connected nodes. BA model provides a unifying framework for the emergence of cooperation. But interestingly, we found that on hierarchical model, there is no sign of cooperation for PD game, while the frequency of cooperation decreases as the common benefit decreases for SG. By comparing the scaling clustering coefficient properties of the hierarchical network model with that of BA model, we found that the former amplifies the effect of hubs. Considering different performances of PD game and SG on complex network, we also found that common benefit leads to cooperation in the evolution. Thus our study may shed light on the emergence of cooperation in both natural and social environments.  相似文献   

8.
Operational reliability evaluation theory reflects real-time reliability level of power system. The component failure rate varies with operating conditions. The impact of real-time operating conditions such as ambient temperature and transformer MVA (megavolt-ampere) loading on transformer insulation life is studied in this paper. The formula of transformer failure rate based on the winding hottest-spot temperature (HST) is given. Thus the real-time reliability model of transformer based on oper- ating conditions is presented. The work is illustrated using the 1979 IEEE Reliability Test System. The changes of operating conditions are simulated by using hourly load curve and temperature curve, so the curves of real-time reliability indices are ob- tained by using operational reliability evaluation.  相似文献   

9.
Titanium dioxide (TiO_2) thin film was deposited on the surface of the light addressable potentiometric sensor (LAPS) to modify the sensor surface for the non-labeled detection of DNA molecules. To evaluate the effect of ultraviolet (UV) treatment on the silanization level of TiO_2 thin film by 3-aminopropyltrietboxysilane (APTS), fluorescein isothiocyanate (FITC) was used to label the amine group on the end of APTS immobilized onto the TiO_2 thin film. We found that, with UV irradiation, the silani-zation level of the irradiated area of the TiO_2 film was improved compared with the non-irradiated area under well-controlled conditions. This result indicates that TiO_2 can act as a coating material on the biosensor surface to improve the effect and effi-ciency of the covalent immobilization of biomolecules on the sensor surface. The artificially synthesized probe DNA molecules were covalently linked onto the surface of TiO_2 film. The hybridization of probe DNA and target DNA was monitored by the recording of Ⅰ-Ⅴ curves that shift along the voltage axis during the process of reaction. A significant LAPS signal can be detected at 10 μmol/L of target DNA sample.  相似文献   

10.
基于结构健康监测的润扬悬索桥有限元模型修正与验证   总被引:5,自引:0,他引:5  
采用大型有限元分析软件ANSYS建立了润扬悬索桥的三维有限元模型并对其进行了自振特性分析,同时计算了各种工况下大桥的应力及位移响应.基于灵敏度的物理意义以及罚函数的思想,提出了一种结构有限元模型修正的新方法.该方法仍以自振特性为目标函数,以结构设计参数为待修正参数,但设计参数的上下限根据测试所得静力响应值和理论值的对比以及工程经验来确定,因此静力响应可用于验证修正后的有限元模型.采用结构健康监测系统数据及提出的方法对大桥有限元模型进行了修正与验证,得到了能够较好地反映大桥整体动静力性能的有限元基准模型,为润扬悬索桥的健康监测和损伤预警提供了研究基础.  相似文献   

11.
针对当传染病发生时医药物资的配送对于应急需求响应至关重要这一特点,以在一定区域内发生传染病疫情为研究背景,根据传染病扩散规律和疫区紧急救助程度的不同,研究了具有多个疫区和多个应急配送中心的疫苗配送最优方案.引入具有脉冲接种的SIQR模型来描述传染病的扩散规律和获得各区域疫苗需求量,在SIQR模型的基础上,利用SOM神经网络将各疫区进行聚类并量化结果.以实现运输成本和缺货量最小为目标,在聚类的基础上建立了动态的疫苗配送模型.以20个受感染区域和4个分布中心为例,给出了算例和仿真分析,结果表明所提出的方法有助于控制具有较高紧急等级区域的疫情,且与不使用聚类方法进行疫苗配送相比,利用聚类方法能更好地控制疫情扩散.  相似文献   

12.
To establish a financial early-warning model with high accuracy of discrimination and achieve the aim of long-term prediction, principal component analysis (PCA), Fisher discriminant, together with grey forecasting models are used at the same time. 110 A-share companies listed on the Shanghai and Shenzhen stock exchange are selected as research samples. And 10 extractive factors with 89.746% of all the original information are determined by applying PCA, which obtains the goal of dimension reduction without information loss. Based on the index system, the early-warning model is constructed according to the Fisher rules. And then the GM(1,1) is adopted to predict financial ratios in 2004, according to 40 testing samples from 2000 to 2003. Finally, two different methods, a self-validated and a forecasting-validated, are used to test the validity of the financial crisis warning model. The empirical results show that the model has better predictability and feasibility, and GM(1,1) contributes to the ability to make long-term predictions.  相似文献   

13.
Sensor localization is crucial for the configuration and applications of wireless sensor network (WSN). A novel distributed localization algorithm, MDS-DC was proposed for wireless sensor network based on multidimensional scaling (MDS) and the shortest path distance correction. In MDS-DC, several local positioning regions with reasonable distribution were firstly constructed by an adaptive search algorithm, which ensures the mergence between the local relative maps of the adjacent local position regions and can reduce the number of common nodes in the network. Then, based on the relationships between the estimated distances and actual distances of anchors, the distance estimation vectors of sensors around anchors were corrected in each local positioning region. During the computations of the local relative coordinates, an iterative process, which is the combination of classical MDS algorithm and SMACOF algorithm, was applied. Finally, the global relative positions or absolute positions of sensors were obtained through merging the relative maps of all local positioning regions. Simulation results show that MDS-DC has better performances in positioning precision, energy efficiency and robustness to range error, which can meet the requirements of applications for sensor localization in WSN.  相似文献   

14.
在分析技术接受模型(technology acceptance model,TAM)和任务技术匹配(task technology fit,TTF)整合的必要性的基础上,运用基于TAM和TTF整合的信息技术接受模型,采取二手资料和开放式问卷调查获取影响因素,构建出P2P网络借贷投资者接受模型。模型研究表明:感知风险是阻碍投资者使用P2P平台进行投资的最重要的影响因素。感知有用、感知收益和感知信任从一定程度上能促进投资者使用P2P平台进行投资。政策法规、P2P平台的质量、主观规范、感知行为控制对P2P平台投资也会产生一定的影响。同时,结合本研究模型提出了针对P2P平台应用和推广的建议。  相似文献   

15.
MRI and PET images fusion based on human retina model   总被引:1,自引:0,他引:1  
The diagnostic potential of brain positron emission tomography (PET) imaging is limited by low spatial resolution. For solving this problem we propose a technique for the fusion of PET and MRI images. This fusion is a trade-off between the spectral information extracted from PET images and the spatial information extracted from high spatial resolution MRI. The proposed method can control this trade-off. To achieve this goal, it is necessary to build a multiscale fusion model, based on the retinal cell photoreceptors model. This paper introduces general prospects of this model, and its application in multispectral medical image fusion. Results showed that the proposed method preserves more spectral features with less spatial distortion. Comparing with hue-intensity-saturation (HIS), discrete wavelet transform (DWT), wavelet-based sharpening and wavelet-à trous transform methods, the best spectral and spatial quality is only achieved simultaneously with the proposed feature-based data fusion method. This method does not require resampling images, which is an advantage over the other methods, and can perform in any aspect ratio between the pixels of MRI and PET images.  相似文献   

16.
研究了在语音传输过程中由于参数丢失导致语音质量急剧下降的丢帧补偿问题.利用大规模隐式马尔可夫模型对自适应多速率宽带语音编码(AMR-WB)的ISF参数进行建模,然后对丢失的ISF参数进行基于最小均方误差(MMSE)准则的最优估计,将估计的ISF参数和前帧的ISF参数进行加权以平滑估计值,得到补偿的ISF参数.在接收端,利用ISF参数的估计值进行语音合成.将本算法的合成语音和由G.722.2标准附件Ⅰ的基准补偿的合成语音进行比较,仿真结果表明,本补偿算法可以得到更好的性能,在频率加权谱失真和信噪比这2种评价准则上都有所改善,信噪比提高约2.41 dB,频率加权谱失真下降约0.885 dB,证明了该算法的有效性.  相似文献   

17.
Objective video quality assessment plays a very important role in multimedia signal processing. Several extensions of the structural similarity (SSIM) index could not predict the quality of the video sequence effectively. In this paper we propose a structural similarity quality metric for videos based on a spatial-temporal visual attention model. This model acquires the motion attended region and the distortion attended region by computing the motion features and the distortion contrast. It mimics the visual attention shifting between the two attended regions and takes the burst of error into account by introducing the non-linear weighting fimctions to give a much higher weighting factor to the extremely damaged frames. The proposed metric based on the model renders the final object quality rating of the whole video sequence and is validated using the 50 Hz video sequences of Video Quality Experts Group Phase I test database.  相似文献   

18.
实训基地建设是高等职业教育办学工作的重要组成部分,是提高实训教学质量的基本保障。以江苏农林职业技术学院每个系为1个决策单元,通过建立数据包络分析模型,对8个决策单元的校内实训基地建设进行绩效评价。结果表明,8个决策单元的实训基地运行状况较为理想,技术效率DEA有效的结果优于规模效率。通过绩效评价能使实训基地管理效率得到不断提升,实训资源配置更加优化。  相似文献   

19.
应用向量自回归EGARCH模型,对中国黄金市场与外汇市场间的收益与波动溢出效应进行经验分析。研究显示:美元兑人民币汇率和中国黄金不存在收益溢出效应,欧元兑人民币汇率对黄金存在负向溢出效应;危机期间市场之间新息冲击的"杠杆效应"减弱,对黄金走势持乐观态度,但波动性比较大。  相似文献   

20.
为了方便工程设计以及沿海防洪减灾,对可能由台风引起的风暴潮进行了研究.利用三角形非结构网格建立ADCIRC水动力模型和SWAN波浪模型的耦合模型,并将其应用于江苏沿海风暴潮和波浪研究.风速、潮位和波高的验证表明该ADCIRC+SWAN耦合模型可以很好地模拟研究区域的水位和波高.研究结果表明辐射应力对风暴潮计算结果有影响,且在如江苏沿海和长江口此类的浅水区域影响更为显著.模型计算的水位结果在江苏沿海得到工程应用,例如风暴潮预警和极端水位预测.  相似文献   

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