80 research outputs found

    自然灾害环境风险评价研究进展

    Get PDF
    总结了国内外关于自然灾害风险评价的研究现状,包括了自然灾害风险的定义、分类以及风险评价的研究进展。在次基础上分析了当前自然灾害风险评价存在的问题,并提出了建议和展望

    水库水源保护区生态补偿机制的探讨

    Get PDF
    本论文提出建立水库水源保护区的生态补偿机制作为长效机制以解决水源保护问题;对生态补偿的定义、建立生态补偿的必要性、定量研究、补偿费分摊率的确定以及资金的来源进行了探讨

    The Hydraulic Cylinder with Extensive Position Controlled Piston Rod

    Get PDF
    该文介绍了一种活塞杆伸出量可测并可控的液压缸。该缸利用滚珠丝杆将活塞杆的直线位移转化为丝杆角位移的方法进行位置测量,其结果由光栅编码器输出并传送到控制中心,由控制中心控制伺服阀的阀口方向和开口大小,从而对液压缸活塞杆产生控制作用。本文对其原理进行了阐述,并对可能存在的测量误差进行了分析。This paper introduces a hydraulic cylinder that its piston rod extension can be effectively controlled,linear displacement of the piston rod can be changed into the screw angular displacement by ball screw,then the distance are outputted by grating angular displacement sensor to the control center,valve port opening direction and size are controlled by the control center and then hydraulic cylinder piston rod is controlled so.This paper describes its principles and demonstrates its feasibility

    Excel软件在环境监测数据处理中的应用

    Get PDF
    环境监测在环境保护中的作用日益显著,随着自动化监测设备的发展和普及,在我国不少水系、饮用水和污染源等地方广泛使用。自动监测数据较以往的人工监测数据有了新的特点,如数据量大、监测时间长、污染事故的预警预报。如何充分使用监测数据,发挥其在环境保护中的作用?传统的监测数据处理,要通过几个Excel命令操作,本文尝试将Excel功能之一的“数据分析”中的“描述统计”命令对自动监测数据进行分析处理。该命令处理后的结果表明,简单的一个命令就可以分析出数据的特点,可以减少监测数据分析人员的工作量。同时,也便于监测数据的利用,对环境评价具有实用性

    正交匹配追踪和BIC准则的自适应双频段预失真模型优化算法

    Get PDF
    针对双频段预失真模型复杂度高以及当前的模型优化算法不具有自适应性的问题,提出一种自适应的模型优化算法.采用双频段广义记忆多项式作为预失真模型,通过正交匹配追踪算法对原始模型的基函数项进行排序,每次迭代时用所有已挑选的基函数项构成备选模型,推导了模型输出向量元素服从非独立同分布情况下的贝叶斯信息准则(Bayesian Information Criterion,BIC),并将BIC值最小的备选模型作为优化后模型,从而在原始模型稀疏度和拟合误差门限未知情况下,实现了模型的自适应优化.结果表明:优化后模型与原始模型相比,二者分别预失真后的信号在邻道功率比和归一化均方误差方面均非常接近,预失真效果良好,而模型的系数量减少了75%以上.国家自然科学基金项目(No.61401099);;福建省教育厅项目(No.JAT170087

    Optimization of camera calibration process based on PSO algorithm

    Get PDF
    摄像机标定为机器视觉在物体位姿与姿态的测量过程中最重要一环,其映射物体三维空间与二维图像之间关系是一个复杂非线性最优化问题。为了更好地解决这一复杂优化问题,阐述了利用粒子群优化(PSO)算法计算摄像机标定过程的一种优化方法,重点描述了PSO算法的原理,单目视觉测量系统,以及基于CMOS摄像机的成像模型及其原理和算法。通过图像软件提取靶体模型上特征控制点,及摄像机标定算法建立了相应的计算公式。结合PSO算法优化像机外参,实验结果表明,PSO算法计算准确、速度快,具有很强的工程应用价值。The camera calibration for machine vision plays an important role in measuring position and pose of objects,it maps the relationship from 3D space objects and 2D image.However,it is a difficult non-linear optimization problem.In order to solve the complex optimization problems,particle swarm optimization(PSO) algorithm was put forward to solve the problem as a kind of optimization method.The method and the related theory of PSO were described,such as the principle of PSO algorithm,the monocular vision measurement system,the imaging model based on CMOS camera and its principle and algorithm.Combined with the PSO algorithm,the experiment results show that this algorithm is accurate,and it has a strong engineering application value.国家自然科学基金资助项目(11072207

    基于切向超滤技术的胶体有机碳和无机氮分离及物源初探

    Get PDF
    利用切向超滤技术对九龙江口天然水体中胶体相(1 kDa~0. 45μm)、真溶解相(<1 kDa)和\"溶解相\"(<0. 45μm)的溶解有机碳和无机氮进行了分离与提取,初步探讨了水环境因子对其理化特性的影响机制,进而探讨了它们的来源和转化.结果表明,切向超滤过程的膜空白和质量平衡符合技术要求;溶解有机碳、亚硝酸盐氮、氨氮、硝酸盐氮和无机氮存在形式以真溶液相(<1 kDa)为主,其在胶体相中的质量浓度分别为0. 207~0. 810 mg/dm3、0. 001~1. 870μg/dm3、ND~2. 08μg/dm3、0. 62~79. 30μg/dm3和1. 07~81. 10μg/dm3;胶体态溶解有机碳(COC)含量主要受陆源输入控制.国家海洋局海洋公益性行业科研专项资助项目(201505034-4);;福建省科学技术厅公益专项资助项目(2015R1003-12

    Structural,Electrical,and Optical Properties of Transparent Conductive Al-Doped ZnO Films Prepared by RF Magnetron Sputtering

    Get PDF
    室温下采用RF磁控溅射技术在石英衬底上制备了多晶ZnO:Al(AZO)透明导电薄膜,通过XRD,AFM,AES,Hall效应及透射光谱等测试研究了RF溅射功率、氩气压强对薄膜的结构、电学和光学性能的影响.分析表明:在最优条件下(溅射功率为250W,氩气压强为1.2Pa时),180nmAZO薄膜的电阻率为2.68×10-3Ω.cm,可见光区平均透射率为90%,适合作为发光二极管和太阳能电池的透明电极.所制备的AZO薄膜具有c轴择优取向,晶粒间界中的O原子吸附是限制薄膜电学性能的主要因素.Highly conductive transparent Al-doped zinc oxide(AZO)films with highly(002)-preferred orientation were successfully deposited on glass substrates at room temperature by RF magnetron sputtering.Optimization of deposition parameters was based on sputtering RF power and Ar pressure in the vacuum chamber.AZO films of 180nm with an electrical resistivity as low as 2.68×10-3 Ω·cm and an average optical transmission of 90% in the visible range were obtained at RF power of 250W and Ar pressure of 1.2Pa.The effect of chemisorption of oxygen on the grain boundary would capture electrons from conduction band and lead the formation of potential barriers among the crystallites,which will influence the electric property of the AZO thin films.The films have satisfactory properties of low resistance and high transmittance for application as transparent conductive electrodes in light emitting diodes(LEDs)and solar cells

    Identification and analysis of odor of patients with exterior syndrome based on medical electronic nose

    Get PDF
    目的:运用自主研发的医用电子鼻探讨表证患者口腔呼气的气味图谱特征及气味识别准确率。方法:选择表证青年患者150例和健康青年人200名,运用基于薄膜型气体传感器阵列技术的医用电子鼻(nAnOfIlM-EnOSE MEdICAl001)采集口腔呼气的气味图谱,以响应曲线的振幅和上升斜率作为曲线特征,分析表证患者及其寒热病性的图谱特征,并进行判别分析。结果:表寒证和表热证患者的气味图谱响应曲线A、b、d、E、g、H的振幅和上升斜率均显著高于健康学生(P<0.01)。表热证患者的气味图谱响应曲线A、b、d、E、H的振幅和上升斜率均显著高于表寒证患者(P<0.05,P<0.01),表热证患者的气味图谱响应曲线g的振幅显著高于表寒证患者(P<0.01)。判别分析显示对健康青年人、表寒证青年患者、表热证青年患者口腔呼气的识别准确率分别为90.5%、86.5%、88.0%,对全部案例的识别准确率为89.1%。结论:表证青年患者口腔呼气的气味较健康青年人浓烈,且表热证青年患者气味变化较表寒证青年患者更明显,本医用电子鼻能够较为敏感和准确地辨识表证青年患者口腔呼气的气味特征及其寒热病性。医用电子鼻技术的发展可为中医嗅诊客观化研究提供手段和方法。Objective: to explore the odor response pattern characteristics of oral breath of patients with exterior syndrome and accuracy rates of odor identiication by medical electronic nose which was independent research and development.Methods: 150 young patients with exterior syndrome and 200 healthy young students were observed.Odor response patterns of oral breath were collected by the electronic nose(Nanoilm-Enose Medical001) based on a ilm of gas sensor array.The amplitude and rising slope of response curves were selected as curve characteristics to analyze pattern characteristics of exterior syndrome including exterior cold syndrome and exterior heat syndrome,and discriminant analysis was done.Results: In odor response patterns of patients with exterior cold syndrome and with exterior heat syndrome,the amplitudes and rising slopes of response curve A,B,D,E,G and H were signiicantly higher than those of healthy students(P<0.01).In odor response patterns of patients with exterior heat syndrome,the amplitudes and rising slopes of response curve A,B,D,E and H were signiicantly higher than those of patients with exterior cold syndrome(P<0.05,P<0.01),and the amplitude of response curve G was signiicantly higher than that of patients with exterior cold syndrome(P<0.01).Discriminant analysis showed that the accuracy rate of oral breath identiication of healthy students,patients with exterior cold syndrome and patients with exterior heat syndrome was 90.5%,86.5% and 88.0% respectively,and the accuracy rate of all cases was 89.1%.Conclusion: The odors of oral breath of patients with exterior syndrome were signiicantly stronger than those of healthy people.The odors of patients with exterior heat syndrome were signiicantly stronger than those of patients with exterior cold syndrome.This medical electronic nose could distinguish odor characteristic of oral breath of patients with exterior syndrome sensitively and accurately;and it could also distinguish odor characteristic of exterior cold syndrome from exterior heat syndrome.The development of medical electronic nose could provide a kind of new means for the study on the objectiication of TCM smelling examination.国家自然科学基金项目(No.30901899); 福建省教育厅A类项目(No.JA09132)~

    Study on odor response patterns of patients with exterior syndrome based on electronic nose technology

    Get PDF
    目的:运用电子鼻技术探讨表证患者口腔呼气的气味图谱特征。方法:选择表证患者(青年学生)114例和健康青年学生255名,运用基于薄膜型气体传感器阵列技术的医用电子鼻(nAnOfIlM-EnOSE MEdICAl001)采集口腔呼气的气味图谱,以响应曲线的振幅和上升斜率作为曲线特征,分析表证患者及其寒热病性的图谱特征。结果:1表证患者的气味图谱响应曲线A、b、d、E、g、H的振幅和上升斜率均显著高于健康学生(P<0.05,P<0.01)。2表寒证和表热证患者的气味图谱响应曲线A、b、d、E、g、H的振幅均显著高于健康学生(P<0.05,P<0.01)。3表寒证患者的气味图谱响应曲线A、b、d、g的上升斜率显著高于健康学生(P<0.05,P<0.01)。表热证患者的气味图谱响应曲线A、b、d、E、g、H的上升斜率显著高于健康学生(P<0.05,P<0.01)。4表热证患者的气味图谱响应曲线A、b、d、E、H的振幅和上升斜率均显著高于表寒证患者(P<0.05)。结论:表证患者口腔呼气的气味较健康人浓烈,且表热证患者气味变化较表寒证患者更明显,本电子鼻能够较为敏感和准确地辨识表证患者口腔呼气的气味特征及其寒热病性,电子鼻技术的发展可为中医嗅诊客观化研究提供手段和方法。Objective: To explore the odor response pattern characteristics of oral breath of patients with exterior syndrome by electronic nose.Methods: 114 patients with exterior syndrome(young students) and 255 healthy young students were observed.Odor response patterns of oral breath were collected by the electronic nose(Nanofilm-Enose Medical001) based on a thin film of gas sensors array.The amplitude and rising slope of response curves were selected as curve characteristics to analyze pattern characteristics of exterior syndrome including exterior cold syndrome and exterior heat syndrome.Results: ①In odor response patterns of patients with exterior syndrome,the amplitudes and rising slopes of response curve A,B,D,E,G and H were significantly higher than those of healthy students(P<0.05,P<0.01).②In odor response patterns of patients with exterior cold syndrome and with exterior heat syndrome,the amplitudes of response curve A,B,D,E,G and H were significantly higher than those of healthy students(P<0.05,P<0.01).③In odor response patterns of patients with exterior cold syndrome,the rising slopes of response curve A,B,D and G were significantly higher than those of healthy students(P<0.05,P<0.01).In odor response patterns of patients with exterior heat syndrome,the rising slopes of response curve A,B,D,E,G and H were significantly higher than those of healthy students(P<0.05,P<0.01).④In odor response patterns of patients with exterior heat syndrome,the amplitudes and rising slopes of response curve A,B,D,E and H were significantly higher than those of patients with exterior cold syndrome(P<0.05).Conclusion: The odors of oral breath of patients with exterior syndrome were significantly stronger than those of healthy people.The odors of patients with exterior heat syndrome were significantly stronger than those of patients with exterior cold syndrome.This electronic nose could distinguish odor characteristics of oral breath of patients with exterior syndrome sensitively and accurately;and it could also distinguish odor characteristics of exterior cold syndrome from exterior heat syndrome.The development of electronic nose could provide a kind of new means for the study on the objectification of TCM smelling examination.国家自然科学基金项目(No.30901899); 福建省教育厅A类项目(No.JA09132)~
    corecore