智能电磁流量计抗干扰技术的研究

本文简要阐述了几种电磁流量计 (EMF)的抗干扰技术。同时 ,讨论了电磁流量计三类干扰噪声产生的物理机理和特征。研究了矩形波励磁型智能电磁流量计的硬件和软件抗干扰技术 ,为实现智能电磁流量计的高精度、高可靠性、高抗干扰能力奠定了坚实的技术基础。     

对电磁流量计中干扰问题的讨论

作为一种新型的流量测量仪表,电磁流量计在最近几年里获得了长足的发展,其以自身优良的性能和特点被广泛应用于工业领域中各种导电液体的流量测量,同时在食品、化工以及水处理等行业中各类浆液流量的测量中也有所应用。虽然与其它流量计相比,电磁流量计有着诸多优点,但它也有一定的缺陷,即容易受到外界的干扰。为此,在应用电磁流量计时,必须采取有效的抗干扰措施,这对于确保测量结果的准确性具有非常重要的意义。基于此点,本文就电磁流量计中干扰问题展开探讨。     

电磁流量计在水厂流量测量中的应用

首先介绍电磁流量计在水厂流量测量中的应用,然后简述电磁流量计的测量原理、优点;根据性能价格比选择流量计;从安装、环境条件和流体特性等方面,论述它在安装调试、运行期的故障。最后介绍清洗探头、防雷电,抗干扰等措施的解决方法。     

电磁流量计在线诊断技术的发展

确保电磁流量计在应用过程中的精度一直是用户所关心的问题，尤其是在给水行业，随着行业的扩展和流量计制作技术的发展，传统的断流取表外送检验的方式已不能满足需要．因此电磁流量计的应用者和制造商都希望有一种在线的电磁流量计检验方法．来替代传统的离线检验方法。     

电磁屏蔽机理和设计分析

本文介绍了电磁干扰形成的原因,电磁兼容的机理以及电磁屏蔽的技术原理,通过介绍电磁干扰来了解到抗电磁干扰的重要性;从研究电磁屏蔽的技术原理与设计措施来比较各种方法的优缺点,从而说明采用电磁屏蔽在生活中不容忽视的优点等抗干扰措施的必要性。     

四电极电磁流量计磁场分布特性数值模拟

文章开展了四电极电磁流量计磁场分布数值模拟研究工作.采用有限元分析方法计算了四电极电磁流量计磁场分布特性,考察了四电极电磁流量计权重函数分布.分析了仪器偏心、流体磁导率对磁场分布影响.为正确理解注聚井中四电极电磁流量计测量响应特性提供了理论分析基础,指出了采用有限元技术是分析电磁流量计测量特性的较好途径.     

电磁流量计的空管检测

本文介绍了电磁流量计空管干扰的原理 ,并介绍了一种简单、可靠的空管检测电路。     

静态质量法小口径流量计检定装置控制系统中干扰因素分析及措施

静态质量法小口径流量计检定装置中 ,采用计算机对检定过程进行控制 ,由于现场存在电磁动力设备和其他影响因素 ,因此要保证控制系统稳定可靠地运行 ,必须对控制系统实行抗干扰措施     

电磁流量计的空管干扰及干扰闭锁

本文分析电磁流量计在空管状态下的干扰机理，进行了实验测试，并给出一种实用的阻断空管干扰的闭锁电路。     

智能旋进漩涡流量计在安装、使用中应注意的问题

近年来．智能旋进漩涡流量计由于其使用方便、价廉物美的特点,在中小气站、中小天然气用户中得到了广泛的应用．然而．由于对智能旋进漩涡流量计安装及日常使用、维护保养的不合理．造成了智能旋进漩涡流量计存在较大的计量误差。笔者现根据现场使用经验．对流量计安装、使用等相关问题进行探讨。     

Investigation of Composition of Endometallofullerene Extracts

Gases evolved upon heating endometallofullerene (EMF) extracts with La or Y have been investigated. It has been shown that solvent molecules used to release EMF are observed in extracts up to high temperatures. It has been found that in the dimethylformamide (DMF) extract the EMF molecules are present mainly as the [EMF]^- anions, which were observed in electrospray mass spectra. The treatment of such extracts with iodine results in the anion reduction to neutral molecules.     

Investigation of Composition of Endometallofullerene Extracts

Abstract

Gases evolved upon heating endometallofullerene (EMF) extracts with La or Y have been investigated. It has been shown that solvent molecules used to release EMF are observed in extracts up to high temperatures. It has been found that in the dimethylformamide (DMF) extract the EMF molecules are present mainly as the [EMF]^? anions, which were observed in electrospray mass spectra. The treatment of such extracts with iodine results in the anion reduction to neutral molecules.     

电磁成形技术的最新进展

电磁成形是目前应用最广泛的高能率成形方法之一.综述了成形磁场力的求解方法及解决电磁成形问题的3个主要方面内容,包括磁场、磁场力及变形,阐述了电磁成形工艺的成形方法及研究现状,列举了大量的国内、外工艺应用及研究成果,介绍了电磁成形工艺的最新应用--电磁校形、粉末压实,并展望了电磁成形技术的发展前景.     

Designing printed circuit stators for brushless permanent magnet motors

Progress in a number of areas of technology has made printed circuit motors a serious contender for many applications. Modern cost effective neodymium magnets have allowed compact motor designs. Multi-layer circuit board production techniques have made the production of printed circuit coils cheaper and easier. However, in spite of the growing importance of printed circuit brushless motors, there is a lack of analytical tools to assist with their design. Geometrical analysis has been used to allow the plotting of printed circuit tracks to be carried out more systematically. The track plotting procedures have been linked with the finite element method to predict rotational electromotive force (EMF) waveforms. Six prototype motors were built and they were used to experimentally validate the method of predicting EMF waveforms. A general design algorithm is presented based on the suggested track plotting procedure and the EMF prediction technique.     

Development of a High-Speed Permanent-Magnet Brushless DC Motor for Driving Embroidery Machines

We describe the development of a permanent-magnet (PM) brushless DC motor for driving high-speed embroidery machines by employing advanced design and analysis techniques. In the design of the motor, magnetic field finite-element analyses accurately calculate the key motor parameters such as the air-gap flux, back electromotive force (EMF), and inductance. Using the numerical magnetic field solutions, a modified incremental energy method calculates the self and mutual inductances of the stator windings. A phasor diagram is derived to compute the motor's steady-state characteristics. To predict the dynamic performance and increase the prediction accuracy, a Simulink-based model simulates the motor performance with the real waveforms of applied phase voltage, back EMF, and current. The motor prototype tested with both a dynamometer and a high-speed embroidery machine validated the theoretical calculations.     

N-step linear phase-shifting algorithms with optimum signal to noise phase demodulation

The wave side of wave–photon duality, describing light as an electromagnetic field (EMF), is used in this article. The EMF of spontaneous light emission (SE) of a laser-excited atom is calculated from first principles for the first time. This calculation is done using the simple method of atomic quantum electrodynamics. The EMF of SE is also calculated for three types of polyatomic light sources excited by a laser. It is shown that light radiated by such sources can be coherent, which explains recent experiments on SE of laser-excited atoms. Small sources of SE can be superradiant, which also conforms to experiment. Thus, SE is shown not to be a random event itself. Random properties of natural light are simply explained as a result of thermal excitation randomness without additional hypotheses. The EMF of SE is described by simple complex functions, but not real ones.     

FeNi29Co18MnSi合金材料热电特性的影响研究

主要研究了FeNi29CO18MnSi合金材料的热电特性,分析了Ni-Co合金、Ni-Fe合金的热电性能,研究了FeNi29Co18MnSi合金中Mn、Si含量及冷形变对合金热电势的影响.研究表明,随着微量添加元素Mn、Si含量的增加,合金单极对铂(Pt)的热电势绝对值减小,且合金冷形变对热电势具有较大的调整作用.     

不同热处理状态铝合金在电磁成形条件下的成形性研究

目的 研究不同热处理状态下多种铝合金在准静态拉伸和电磁单向拉伸条件下的成形性能,并探究其中机理.方法 选择不同牌号(1060,3003,5052)和不同热处理状态(加工硬化态和完全退火态)的铝合金材料,获得材料在准静态和电磁成形条件下材料的成形性能,并通过扫描电镜(SEM)和透射电镜(TEM)对1060铝合金试样进行显微断口和微观组织分析.采用数值仿真方法,获取板料和线圈的最佳相对位置.结果 与退火态材料相比,在电磁成形条件下加工硬化态材料的成形性能提高得更多,特别是在1060铝合金中,退火态试样准静态拉伸的伸长率和动态拉伸的伸长率几乎一致,而H24态试样的动态拉伸伸长率(20.2％)为准静态拉伸(5.1％)的3.96倍.扫描断口发现电磁成形断裂面更窄,韧窝大小更均匀.1060-O试样电磁成形后,晶粒内部位错密度低,微观结构主要为亚晶.1060-H24试样电磁成形后的组织中位错密度较高,出现位错胞.结论 加工硬化态材料中存在的初始缺陷有利于电磁成形过程中位错的产生和交滑移的发生,从而提高合金成形性.     

变速箱结构设计专家系统技术的研究

结构设计是机械产品设计过程中的重要环节，解决结构设计的智能化不但可以缩短产品的设计周期，而且还可以降低成本，提高设计质量。专家系统是解决智能化设计的技术之一。本文讨论有关结构专家系统的几个关键技术，主要包括系统的控制策略，面积对象的知识表达方式及结构设计的并行设计     

数字化智能化产品设计方法与技术的发展

目的 回顾产品设计方法与技术的发展经历,建立设计方法与技术的定式化分类框架,分析数字化智能化产品设计技术的研究与应用热点,展望智能化创新设计技术的未来发展趋势与挑战。方法 通过对已有的产品设计方法与技术的分析,将设计对象、设计阶段、设计资源、设计手段作为设计方法与技术的分类要素,构建设计方法与技术的定式化分类框架;通过确定各分类要素的具体内容,可以明确不同的设计方法与技术,如数字化智能化产品设计技术;利用该定式化分类框架,展望未来数字化智能化产品设计技术的发展趋势。结论 提出了一种用于产品设计方法与技术定式化的分类框架,界定了基于模型的系统设计与仿真优化、基于互联网的开放式众包设计和数据驱动的设计等三个热点研究方向,指出了产品全生命周期一体化设计、混合智能驱动的创新设计的趋势与挑战。