6 resultados para DTM
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
随着自动化程度的不断提高,对设备的种类要求越来越广泛,由此带来的设备配置工作越来越繁琐。设备描述技术和FDT/DTM技术的出现解决了这个问题。本文在对这两种技术研究的基础上,从技术实现的角度上对这两种技术做了分析,并提出了一种多技术结合的方法,以适用于复杂多样的工业应用环境。
Resumo:
本文对国际上十分活跃的领域景观生态-概念、范畴、发展状况,人们的认识和研究概况做了仔细的综述,并提出了运用景观生态的综合整体思想进行大比例尺地学-生态学研究的基本模式,该模式分为以下几个阶段:景观调查-景观与景观要素制图-景观(生态分析)-景观评价-景观规划-景观动态监测-景观预测-景观管理。以辽西山地丘陵区为例,对这一模式进行了实践,研究并建立了大比例尺景观管理信息系统。在整个研究中即对每一个过程的独立性予以了分考虑,又对整个过程的系统性给予了高度重视,使水平和垂直的研究有机地结合。在LMIS有力的数据、图形、图像等处理功能的支持下,对工作区的基础数据进行了采集、分析、管理与贮存,绘制了各种单因子基础图件,包括土壤图,土地利用现状图,农业地貌图,DTM图,坡度图与坡向图等。在综合研究中进行了景观制图、农业土地评价,林业土地评价和景观生态规划的偿试。从基础的调查到数据的综合评价与系列制图的过程中,体现了景观生态研究的特点,在实践中是重要的。
Resumo:
Two triazole derivatives, 3,4-dichloro-acetophenone-O-1'-(1',3',4'-triazolyl)-methaneoxime (4-DTM) and 2,5-dichloro-acetophenone-O-1'-(1',3',4'-triazolyl)-methaneoxime (5-DTM) were synthesized, and the inhibition effects for mild steel in 1 M HCl solutions were investigated by weight loss measurements, electrochemical tests and scanning electronic microscopy (SEM). The weight loss measurements showed that these compounds have excellent inhibiting effect at a concentration of 1.0 x 10(-3) M. The potentiodynamic polarization experiment revealed that the triazole derivatives are inhibitors of mixed-type and electrochemical impedance spectroscopy (EIS) confirmed that changes in the impedance parameters (R-ct and C-dl) are due to surface adsorption. The inhibition efficiencies obtained from weight loss measurements and electrochemical tests were in good agreement. Adsorption followed the Langmuir isotherm with negative values of the free energy of adsorption Delta G(ads)(o). The thermodynamic parameters of adsorption were determined and are discussed. Results show that both 4-DTM and 5-DTM are good inhibitors for mild steel in acid media.
Resumo:
随着智能仪表的发展,FDT设备集成技术将具有广阔的发展前景。本文分析了FDT技术的特点和应用模式,并结合一个具体FDT设备管理系统的设计说明其在现场总线控制系统中的应用。
Resumo:
化程度的不断提高,在过程控制的现场对设备的种类要求越来越广泛。在这种情况下,大量不同厂商不同类型的设备应用到实际现场中。由此带来的设备配置工作越来越烦索。电子设备描述技术(EDD)和现场设备类型管理技术(FDT/DTM)的出现解决了这个问题。EDDL是描述电子(仪表)设备的语言,是各个不同设备进行互操作的基础。EDDL提供了一整套可裁剪的基本结构元素,用于对简单、复杂或模块化的设备进行描述。EDD是一种统一的、独立于平台的设备操作的基础。FDT/DTM技术是基于软件的设备集成解决方案,采用具有统一接口规范的FDT框架和DTM软件组件,其基本思想是提供标准的方法来管理现场设备。国内外对这两种技术的研究和技术推广逐年升温,研究开发具有自主知识产权的解决方案具有十分重要的意义。本文通过深入研究协议,掌握其关键技术,实现其实际的应用,并开发相应的软件。 介绍了两种协议的原理及应用设计实现过程。根据对协议的研究以及国内外相关应用现状的分析提出设备集成方案设计的思路,以达到实际工程应用的目的。详细介绍了EDD协议与FDT/DTM协议的主要机制,包括设备描述语言、描述方法、编译解释原理、组件技术、COM/ActiveX控件、组件通信等。并以博微公司生产的变送器为例,实现了设备集成的具体应用,包括基于EDDL技术的压力变送器与AMS和PDM集成、基于FDT技术的与美名fdtContainer集成。详细描述了设备集成的原理、集成的方案、设备描述文件的编写、设备DTM的开发等。
Resumo:
Solar ultraviolet (UV) radiation at wavelengths less than 400 nm is an important source of energy for aeronomic processes throughout the solar system. Solar UV photons are absorbed in planetary atmospheres, as well as throughout the heliosphere, via photodissociation of molecules, photoionization of molecules and atoms, and photoexcitation toexcitation including resonance scattering. In this paper, the solar irradiances data measured by TIMED SEE, as well as the solar proxies such as F10.7 and Mg II, thermosphere neutral density of CHAMP measurements and topside ionospheric plasmas densities from DMSP, are used to analyze solar irradiance effects on the variabilities of the thermosphere and the ionosphere. First, thermosphere densities near 410 km altitude are analyzed for solar irradiance variability effects during the period 2002-2004. Correlations between the densities and the solar irradiances for different spectral lines and wavelength ranges reveal significantly different characteristics. The density correlates remarkably well with all the selected solar irradiances except the lower chromospheric O I (130.4 nm) emission. Among the chosen solar proxies, the Mg II core-to-wing ratio index, EUV (30-120 nm) and F10.7 show the highest correlations with the density for short-term (< ~27 days) variations. For both long- (> ~27 days) and short-term variations, linear correlation coefficients exhibit a decreasing trend from low latitudes towards high latitudes. The density variability can be effectively modeled (capturing 71% of the variance) using multiple solar irradiance indices, including F10.7, SEUV (the EUV 30-120 nm index), and SFUV (the FUV 120-193 nm index), in which a lag time of 1 day was used for both F10.7 and SEUV, and 5 days for SFUV. In our regression formulation SEUV has the largest contribution to the density variation (40%), with the F10.7 having the next largest contribution (32%) and SFUV accounting for the rest (28%). Furthermore, a pronounced period of about 27.2 days (mean period of the Sun's rotation) is present in both density and solar irradiance data of 2003 and 2004, and a pronounced period of about 54.4 days (doubled period of the solar rotation) is also revealed in 2004. However, soft X-ray and FUV irradiances did not present a pronounced 54.4 day period in 2004, in spite of their high correlation with the densities. The Ap index also shows 54-day periodicities in 2004, and magnetic activity, together with solar irradiance, affects the 54-day variation in density significantly. In addition, NRLMSISE00, DTM-2000 and JB2006 model predictions are compared with density measurements from CHAMP to assess their accuracy, and the results show that these models underestimate the response of the thermosphere to variations induced by solar rotation. Next, the equatorial topside ionospheric plasmas densities Ni are analyzed for solar irradiance variability effects during the period 2002-2005. Linear correlations between Ni and the solar irradiances for different wavelength ranges reveal significantly different characteristics. XUV (0-35 nm) and EUV (115-130 nm) show higher correlation with Ni for the long-term variations, whereas EUV (35-115 nm) show higher correlation for the short-term variations. Moreover, partial correlation analysis shows that the long-term variations of Ni are affected by both XUV (0-35 nm) and EUV (35-115 nm), whereas XUV (0-35 nm) play a more important role; the short-term variations of Ni are mostly affected by EUV (35-115 nm). Furthermore, a pronounced period of about 27 days is present in both Ni and solar irradiance data of 2003 and 2004, and a pronounced period of about 54 days is also revealed in 2004. Finally, prompted by previous studies that have suggested solar EUV radiation as a means of driving the semiannual variation, we investigate the intra-annual variation in thermosphere neutral density near 400 km during 2002-2005. The intra-annual variation, commonly referred to as the ‘semiannual variation’, is characterized by significant latitude structure, hemispheric asymmetries, and inter-annual variability. The magnitude of the maximum yearly difference, from the yearly minimum to the yearly maximum, varies by as much as 60% from year to year, and the phases of the minima and maxima also change by 20-40 days from year to year. Each annual harmonic of the intra-annual variation, namely, annual, semiannual, ter-annual and quatra-annual, exhibits a decreasing trend from 2002 through 2005 that is correlated with the decline in solar activity. In addition, some variations in these harmonics are correlated with geomagnetic activity, as represented by the daily mean value of Kp. Recent empirical models of the thermosphere are found to be deficient in capturing most of the latitude dependencies discovered in our data. In addition, the solar flux and geomagnetic activity proxies that we have employed do not capture some latitude and inter-annual variations detected in our data. It is possible that these variations are partly due to other effects, such as seasonal-latitudinal variations in turbopause altitude (and hence O/N2 composition) and ionosphere coupling processes that remain to be discovered in the context of influencing the intra-annual variations depicted here. Our results provide a new dataset to challenge and validate thermosphere-ionosphere general circulation models that seek to delineate the thermosphere intra-annual variation and to understand the various competing mechanisms that may contribute to its existence and variability. We furthermore suggest that the term “intra-annual” variation be adopted to describe the variability in thermosphere and ionosphere parameters that is well-captured through a superposition of annual, semiannual, ter-annual, and quatra-annual harmonic terms, and that “semiannual’ be used strictly in reference to a pure 6-monthly sinusoidal variation. Moreover, we propose the term “intra-seasonal” to refer to those shorter-term variations that arise as residuals from the above Fourier representation.