274 research outputs found

    遥感-岩石力学(III)——交汇断层粘滑的热红外辐射与声发射规律及其构造地震前兆意义

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    以构造地震孕震机制之三即交汇断层粘滑发震为模拟对象,利用双轴加载实验系统和红外热像仪对自然界经常出现的断层组合模式——不同交汇角度的组合断层的物理模型进行了室内加载实验,利用红外热像仪和声发射仪分别测定了加载过程中试样表面的红外辐射及断层活动的声发射时间序列。结果表明:(1) 声发射及红外辐射的时间序列特征受加载过程中试样的力学行为所控制,并表现出阶段性变化特点;(2) 声发射与红外辐射特征与断层几何结构有密切关系,当主应力与主断层成45°角时,红外辐射异常区主要沿主断层发育;(3) 垂直交汇的断层与斜交断层的声发射及红外辐射特征有明显差异,交汇角度(1°~90°)越大,交汇点处的红外辐射异常越明显

    Research on the automatic tool changer system of the machining center

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    自动换刀系统(ATC)包括刀库机构、换刀机构以及控制系统3个部分,是加工中心的重要组件之一。为了解决数控加工中心自动换刀速度慢、稳定性低及控制系统编程复杂等问题,将一种软件式内置PlC技术应用于自动换刀系统中。在分析自动换刀系统的基本结构、工作原理以及研究圆盘刀臂式自动换刀系统的控制流程的基础上,结合SErVOWOrkS CnC技术,开发了适用于各种自动换刀机构的PlC程序以及宏程序。最后,将所开发的控制系统应用于yy-1060立式加工中心,其在4 S~6 S内可完成整个换刀过程。研究结果表明,换刀过程快捷、准确、可靠,完全能够满足使用的要求。The automatic tool changer(ATC),which includes a magazine,a tool changer and a control system,is one of the key components of the machining center(MC).General issues of the ATC,however,are its slowness and low stability during tool changes and the complexity of control system programming.To solve those problems,one type of software and its internal PLC technology were investigated.Based on an analysis of the fundamental structure and operating principle of the ATC system and a research of the control procedure of the "disc with arm"-type ATC,the PLC program and macro programs combined with ServoWorks CNC technology were developed.Finally,it was shown that the newly designed control system can complete the whole process of changing tools in 4 to 6 seconds on the YY-1060 vertical MC.The results indicate that the process is rapid,accurate and reliable enough to completely meet the practical requirements

    Application of EtherCAT fieldbus in servo motion control system

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    为实现ETHErCAT现场总线在伺服运动控制系统中的具体应用,以五轴运动控制系统的研发为背景做了研究与测试。系统主站控制器采用爱迪纳控制技术(厦门)有限公司的AdX CnC纯软件开放式数控系统,从站设备由ETHErCAT从站接口控制器ET1100和dSP芯片组成,并由此构建了一主一从的ETHErCAT网络结构。研究结果表明:该技术可实现系统的实时信号传输和精确位置控制。To achieve the application of EtherCAT fieldbus in servo motion control system,some research and tests were done based on the five-axis motion control system.ADX CNC system was used as the master controller,which is a pure software open CNC system designed by Amoy Dynamics(Xiamen)Co.,Ltd..The slave station was consisted by EtherCAT slave controller ET1100 and digital signal processing(DSP).Research results show that the real-time transmission of signal and accurate position control can be achieved using the one-master and one-slave EtherCAT network structure

    Partitioning and transport of Polycyclic Aromatic Hydrocarbons in surface water from the downstream to Lingdingyang of Pearl River

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    为了研究河口水体中多环芳烃(PAHS)的相态分布、传输特征及其变化趋势,本文沿珠江下游至河口对表层水体PAHS进行采样分析。结果显示,16种优控PAHS的总浓度为(17.50~168.35)ng/l,平均83.40 ng/l,其中溶解相为(3.76~83.60)ng/l,颗粒相为(1.59~84.75)ng/l。PAHS浓度自下游至伶仃洋有波动降低的趋势,该趋势受陆源的持续输入、浮游植物的吸附吸收以及海水的稀释作用等因素的共同影响;PAHS组成及两相分配的变化主要受控于输入特征、悬浮颗粒物和黑碳吸附以及盐析效应等环境因子。荧蒽和芘的分配系数kP自珠江下游至伶仃洋的逐渐下降也说明了海水的稀释显著降低了悬浮颗粒物对PAHS的吸附。另外,特征化合物比值沿程的变化不仅指示了PAHS在广州段水体中较长的停留时间,也说明了虎门河口存在持续的PAHS输入。利用主因子分析和多元线性回归的方法,指示出煤和木材燃烧以及机动车排放是该区域表层水体PAHS污染的最主要来源,约贡献了80%的PAHS输入。In order to study the phase distribution,transport and variation of polycyclic aromatic hydrocarbons(PAHs),surface water samples were collected along the downstream to Lingdingyang of Pearl River.The total concentrations of 16 US EPA PAHs ranged from 17.50 ng /L to 168.35 ng /L with the average of 83.40 ng /L [dissolved phase:(3.76 ~ 83.60) ng /L,particle phase:(1.59 ~ 84.75) ng /L].The declining trend of PAHs concentrations was showed from the downstream to Lingdingyang under the influence of the terrestrial continuous inputs,phytoplankton adsorption and seawater dilution.Variations of PAHs composition and partitioning were controlled by input pathway,adsorption of suspended particulate matters(SPM) and black carbons and the salting out effect.The partition coefficients of Fluo and Py decreased gradually indicated that the water dilution affected the adsorption of SPM to PAHs.In addition,the trend of Fluo /(Py + Fluo) suggested the longer retention time of PAHs in downstream of Pearl River and the continuous inputs of PAHs in Humen estuary.The principal factor analysis indicated the coal and wood combustion and vehicle emissions were the major sources of PAHs in the surface water,which contributed almost 80%of PAHs input.国家自然科学基金项目(41276066

    Improvement of Segmentation Correction Model Based on Local Features

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    基于局部特性的分割校正模型能够在图像分割的同时实现对非均匀场的校正,从而对灰度不均匀图像有较好的分割效果,然而,该模型具有局部特性,且采用多相分割,使得活动轮廓曲线对初始位置较为敏感,且分割速度较慢。针对该不足,通过引入自适应距离保持水平集算法,采用分割校正模型与自适应距离保持水平集相结合的方法,提出一种新的快速分割算法。实验结果表明,该算法可摆脱初始轮廓的限制,避免在分割灰度不均匀图像时边缘泄漏和分割不足现象,并且具有分割快速的特点。Segmentation correction model based on local features can implement the correction of intensity inhomogeneity images,for which has better segmentation effect,but with the local features of the proposed model,and using multiphase segmentation,so that it is sensitive to the initial position of the active contour curve and the segmentation is slow.Aiming at the shortage,a new fast segmentation algorithm is proposed by introducing Adaptive Distance Preserving Level Set(ADPLS) algorithm,combining the segmentation correction model and adaptive distance preserving level set method.Experimental results show that the improved algorithm not only gets rid of the influence of the initial contour,but also avoids the edge leakage and segmentation shortage phenomenon,maintains the fast segmentation.福建省自然科学基金资助项目(2008J0312

    Determination of Estrogenic Compounds in Water of Jiulong River Using Polar Organic Chemical Integrative Sampler

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    极性有机物一体化采样器(POCIS)作为富集水体中有机物的新型采样技术,可以反映目标物在被测水体中的时间权重浓度,因此在环境监测中是对主动采样方式的重要补充.本研究采用POCIS进行了4种固醇类雌激素化合物(雌酮、雌二醇、雌三醇及雌炔醇)的富集动力学,以及温度和目标物浓度对POCIS富集雌激素影响的实验室模拟研究.结果表明,POCIS对目标化合物的富集放置时间7 d内呈现显著的线性关系(r2≥0.988 1,P12%),随着温度的升高,目标化合物在POCIS上的采样速率减小.而目标物浓度对POCIS富集没有显著的影响(rSd 12%).As for different concentrations of target compounds,the sampling rate was not affected by the concentrations( RSD < 5%).After laboratory experiments,an environmental field study was performed in Jiulong River.The results showed that there was a relatively good correlation between the measured and calculated values( r2= 0.720 9,P < 0.001).It demonstrated that POCIS can be used in aquatic field systems.近海海洋环境科学国家重点实验室访问学者基金项目; 海洋公益性行业科研专项(201105013

    Estimation of the sources of organophosphorus pesticides in Xiamen sea area,

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    利用SPEGCFPD对厦门附近海域的微表层、表层、底层海水及九龙江入海口高、低潮水中有机磷农药进行了分析.结果表明,有机磷农药的含量范围为:低于检测限~725.54ng·L-1,平均值为136.47ng·L-1.研究海区中马銮内湾有机磷农药污染最为严重(165.77~453.42ng·L-1,平均296.01ng·L-1),九龙江口、西海域和西南海域污染水平接近(16.26~200.65ng·L-1,平均84.59ng·L-1),东部海域有机磷农药污染最轻(10.38~66.01ng·L-1,平均38.14ng·L-1).九龙江入海口高潮水中农药的浓度明显低于低潮水中浓度,说明海域中多数农药污染来源于九龙江流域输入,少数农药来源于海域周边地区或九龙江流域和海域周边地区共同输入,微表层对有机磷农药的富集作用不明显. 【英文摘要】 Organophosphorus Pesticides (OPPs) were determined in microsurface water, subsurface water and bottom water in Xiamen sea area with SPE-GC-FPD. The result showed that the levels of all OPPs ranged from below detection limit to 725.54ng·L -1, the mean was 136.47ng·L -1. The pollution in Maluan Bay was the most serious(165.77~453.42ng·L -1,mean 296.01ng·L -1) and the Eastern Sea was the slightest(10.38~66.01ng·L -1,mean 38.14ng·L -1). Meanwhile, the levels of OPPs in Jiulong estuary were closed to that in the...国家自然科学基金(No.40106012)~

    磺基水杨酸的分子内质子转移及其在酸性锡电镀液中的荧光快速测定

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    根据磺基水杨酸反常大的荧光Stokes位移的实验现象,提出了它在一定条件下发生分子内质子转移的机理.据此建立了酸性锡电镀液中磺基水杨酸的直接快速荧光分析新方法.该方法不受共存组分干扰,5~10min可完成测定,测定的相对标准偏差小于3%

    Bio-Inspired Aggregation Control of Carbon Nanotubes for Ultra-Strong Composites

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    High performance nanocomposites require well dispersion and high alignment of the nanometer-sized components, at a high mass or volume fraction as well. However, the road towards such composite structure is severely hindered due to the easy aggregation of these nanometer-sized components. Here we demonstrate a big step to approach the ideal composite structure for carbon nanotube (CNT) where all the CNTs were highly packed, aligned, and unaggregated, with the impregnated polymers acting as interfacial adhesions and mortars to build up the composite structure. The strategy was based on a bio-inspired aggregation control to limit the CNT aggregation to be sub 20--50 nm, a dimension determined by the CNT growth. After being stretched with full structural relaxation in a multi-step way, the CNT/polymer (bismaleimide) composite yielded super-high tensile strengths up to 6.27--6.94 GPa, more than 100% higher than those of carbon fiber/epoxy composites, and toughnesses up to 117--192 MPa. We anticipate that the present study can be generalized for developing multifunctional and smart nanocomposites where all the surfaces of nanometer-sized components can take part in shear transfer of mechanical, thermal, and electrical signals
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