共查询到19条相似文献,搜索用时 312 毫秒
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测量无取向电工钢磁性能的方法有爱泼斯坦方圈法和单片法。文章介绍了爱泼斯坦方圈法和单片法测量无取向电工钢所用设备、取样方法、试样尺寸、数量和检测方法等,主要对爱泼斯坦方圈法与单片法测量的检验数据结果进行分析。结果表明,爱泼斯坦方圈法测量铁损值和磁极化强度值的极差值和标准偏差均小于单片法,更精准。爱泼斯坦方圈法取样量大,对试样尺寸要求严格,而单片法取样量小,且偏差在允许范围内,单片法可以代替爱泼斯坦方圈法测量无取向电工钢磁性能。 相似文献
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线性测量系统是化学分析、物理测试领域最普遍的测量系统,按其线性关系的构建和拟合方式,可分为单点校准、双点校准、多点校准(线性拟合)及标准加入法。其中,单点校准常用于色谱分析、滴定分析等分析方法及气体分析、碳硫分析等测量项目。实验引入2个随机效应修正因子或相对随机误差表征各种条件变异及系统波动对校准用标准物质和实际样品测量重复性的影响,提出了蒙特卡洛法(MCM)评定单点校准线性测量系统不确定度的数学模型与方法,并基于惰性气体熔融-热导法测定TC4钛合金中氢含量的示例,系统阐释了MCM的具体评定流程与应用。在实验测量条件下(标准物质重复4次,实际样品重复7次),平均测量结果为w(H)=(20±3)μg/g,k=2,该扩展不确定度评定结果与采用“不确定度传播律”得到被测量估计值测量不确定度的方法(GUM法)相一致。实验所给出的方法和示例可直接应用于气体分析(惰气熔融-红外吸收法/热导法)、碳硫分析(高频感应燃烧红外吸收法)与色谱分析、滴定分析等单点校准线性测量系统的不确定度的评定,一定程度上解决了MCM应用于化学分析领域的模型构建与仪器校准引入不确定度的量值导入等关键问题,有望推动MCM在单点校准、多点校准、标准曲线法、标准加入法等线性测量系统不确定度的评定中得到实质性的应用,进一步促进测量不确定度的应用研究开创新局面。 相似文献
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铁表面镀镍工艺流程中,电镀检测站采用涡流法镀层测厚仪对电镀产品的镍镀层厚度进行测量.在使用随机配置的标准片校准仪器时发现其不适用于电镀产品的测定.本文根据涡流法镀层测厚原理,阐述了如何运用电镀产品自制标准片用于测厚仪的校准,从而大大提高了测量数据的准确性. 相似文献
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针对无速度传感器矢量控制系统中电压模型磁通观察器存在积分运算问题和低速运行时转速难以控制的问题,设计了利用电流模型修正电压模型的磁通观察器和PI自适应法速度观察器,建立了转速电流双闭环调速系统。仿真结果表明:低速下稳态精度比较好,估算速度毛刺较少,系统对转子参数有较强的鲁棒性。仿真证明了该方法的有效性。 相似文献
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多点校准线性测量系统相比单点或两点校准具有更宽的测定范围和更高的准确度、可靠性,在化学分析、物理测试等多个领域都有着广泛的应用。实验提出了蒙特卡洛法(MCM)评定多点校准线性测量系统不确定度的数学模型和仿真模拟方法,并以电感耦合等离子体原子发射光谱法(ICP-AES)测量低合金钢中锰含量为例,介绍了MCM评定测量不确定度的详细步骤和应用方法。首先采用MCM法,根据输入量的概率分布类型,通过模拟抽样分析进行测量不确定度评定,再采用GUM法进行评定。实验结果显示,试样中锰含量的平均测量结果为(0.919±0.012)%,k=1.96,与GUM法计算得到的扩展不确定度一致。给出的方法实现了MCM法在多点校准线性测量系统不确定度评估中的应用,一定程度上解决了标准样品参考值与线性校准波动性引入不确定度量值的导入问题,有助于进一步推动不确定度评估与应用的创新与发展。 相似文献
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采用可调移液枪移取样品溶液,制成溶液滤片,以波长色散X射线荧光光谱仪直接测定了铑镀液中铑的含量。实验表明,利用溶液滤片法绘制的校准曲线线性相关系数为0.999 1,与传统方法制得的校准曲线线性相关系数相一致,且不同体积的溶液在纸片上的扩散不会对测量结果造成影响。该方法样品用量少,消除了基体效应,且校准曲线能够保证长期使用。方法的检出限为11.52 μg。对实际镀铑液样品进行测试,结果同电感耦合等离子体质谱法和火焰原子吸收光谱法测量结果一致,相对标准偏差<2.1%。 相似文献
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Narutoshi Nakata Billie F. Spencer Jr. Amr S. Elnashai 《Canadian Metallurgical Quarterly》2010,136(2):189-198
Due to the nonlinear nature of coordinate transformations, evaluation and calibration of multiaxial loading systems in global Cartesian coordinates are challenging problems. This study proposes a systematic calibration method for multiaxial loading systems in global coordinates using an external measurement system. Global coordinate measurement for a multiaxial loading system is usually obtained from a geometric transformation based on internal actuator measurements. However, any misrepresentation of initial actuator configuration (e.g., origin, pin locations, etc.) introduces errors and cross-talk in the global Cartesian coordinates. Such errors and cross-talk cannot be observed or eliminated based on internal measurements. The method proposed in this paper is based on the sensitivity of the global coordinates with respect to the initial actuator length. To validate the proposed method, calibration is performed using the state-of-the-art Load and Boundary Condition Box at University of Illinois at Urbana-Champaign as the multiaxial loading system and the Krypton Dynamic Measurement Machine as the external measurement system. Experimental results demonstrate that the proposed sensitivity-based external calibration method is effective for improving control accuracy and reducing cross-talk of multiaxial loading systems in global Cartesian coordinates. 相似文献
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A method was developed to determine the activity of specific components in liquid high-temperature metal solutions. A vacuum
furnace was located in the beam path of a commercial atomic absorption spectrophotometer. Direct measurements of the vapor
of an alloy component contained in a Knudsen cell were made. The applicability of the method was proven on the Sn-Mg system,
which has a well-known activity of magnesium. A pseudoisopiestic Knudsen cell containing a slug of pure Mg was used for calibration
of the system.
Formerly Graduate Student, University of British Columbia 相似文献
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采用温压成形工艺将水雾化Fe Si Al粉末制备成磁粉芯;用X射线衍射对原始粉末和经过绝缘包覆及热处理的粉末进行物相分析;采用软磁交流测试仪测量磁粉芯的磁损耗;利用精密磁性元件分析仪测量样品的磁导率。混合不同质量分数的硬脂酸锌和聚乙二醇(PEG)作为温压润滑剂,并研究其对Fe Si Al磁粉芯性能的影响。结果表明,1 100 MPa/100℃的温压成形条件下,当硬脂酸锌和PEG质量比为2:3,添加温压润滑剂的质量分数为1.3%时,磁粉芯生坯密度达到最大值5.75 g/cm3,热处理后为5.74 g/cm3。660℃×1 h热处理后,100 k Hz下,相应的有效磁导率?e达到137.9;350 k Hz/50 m T下磁损耗Ps为81.78 W/kg。 相似文献
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使用盐酸-硝酸-氢氟酸并采用微波消解法处理样品,选择Al 308.215nm和Si212.412nm作为分析线,基体匹配法配制标准溶液系列绘制校准曲线,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铝和硅,从而建立了微波消解-电感耦合等离子体原子发射光谱法(ICP-AES)测定铁硅铝磁芯中铝和硅的方法。结果表明,铝和硅的质量分数分别为1.00%~9.00%和2.50%~12.50%时与其发射强度呈线性,线性相关系数均不小于0.999 4;方法中铝和硅的检出限分别为0.020%和0.021%(质量分数)。实验方法应用于铁硅铝磁芯样品中铝和硅的测定,结果的相对标准偏差(RSD,n=6)为1.4%~2.2%;将测定结果与滴定法(测定铝)和重量法(测定硅)的测定结果进行比对,二者相吻合。 相似文献
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Effect of Structure Parameters on Power and Magnetic Field in Electromagnetic Soft-Contact Continuous Casting System 总被引:1,自引:0,他引:1
To design a power source system and mold for electromagnetic soft-contact continuous casting process and to theoretically estimate the heat losses from the charges and the system power, the effect of structure parameters on system power and magnetic flux density distribution was calculated using finite element method. The results show that as for electromagnetic soft-contact continuous casting system with partial-segment type mold, the power consumption is much more than that with a full-segment type mold; about 62% of electric power is dissipated in the mold, and the effective acting range of magnetic field is relatively narrow. Optimizing mold structure is a crucial measure of remarkably reducing mold power consumption and saving electric energy. Increasing slit number, width, and length can remarkably increase the magnetic flux density in the mold and can reduce the electric energy consumption. Among structure parameters, slit number and slit width are relatively more effective to reduce energy consumption. For a round billet electromagnetic continuous casting system with diameter of 178 ram, the reasonable slit number, width, and length are about 24--32, 0. 5--1.0 mm, and 160 mm, respectively. 相似文献
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Rodents are able to rely on self-motion (idiothetic) cues and navigate toward a reference place by path integration. The authors tested the effects of dorsal hippocampal and parietal lesions in a homing task to dissociate the respective roles of the hippocampus and the parietal cortex in path integration. Hippocampal rats exhibited a strong deficit in learning the basic task. Parietal rats displayed a performance impairment as a function of the complexity of their outward paths when the food was placed at varying locations. These results suggest that the parietal cortex plays a specific role in path integration and in the processing of idiothetic information, whereas the hippocampus is involved in the calibration of space used by the path integration system. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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针对工频配电网中节能变压器、兆瓦级DC/DC变换器中频隔离变压器、柔性低频交流输电领域低频变压器等电力装备对高性能取向硅钢的应用需求,采用任意波形磁场激励软磁测量系统,研究了0.10~0.27 mm不同牌号取向硅钢在不同工作频率下的电磁特性,探讨了薄规格取向硅钢在中低频电力装备中的应用前景。与0.10 mm超薄取向硅钢相比,0.18 mm高磁感取向硅钢在15~400 Hz中低频率范围具有更低的损耗特征。0.18 mm产品不仅在轧向的铁损低于0.23 mm和0.27 mm产品,在横向也具有最低损耗优势;但对于相同厚度材料,轧向低损耗并不意味着横向同样具有低损耗。分析了不同厚度取向硅钢电磁特性差异及原因,结果可支撑各类型变压器铁心材料选型。结合工频、中频和低频领域电力装备技术发展对铁心材料性能要求,展望了薄规格取向硅钢未来的发展趋势。 相似文献
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采用熔融制样,建立了镁质耐火材料(制品镁砖等)及其原料(水镁石,原料镁砂等)中MgO、Al2O3 、SiO2 、CaO、P2O5 、TiO2、TFe2O3、Na2O、K2O、MnO的X射线荧光光谱分析方法。与以往方法相比,增加了Na2O、K2O的含量测试,为最终对于MgO的准确测试提供了依据。对高镁样品(MgO含量大于90%)的熔剂体系、样品与熔剂稀释比等方面进行了考察,同时对水镁石、菱镁矿等高烧失量样品的烧失量校正进行了探讨。采用国家标准样品GBW07105和高纯镁砂配制的系列校准样品来建立校准曲线,用经验系数法回归校正共存元素间的吸收增强效应。方法的检出限在0.031%~0.45%之间。对样品进行了精密度试验,各成分的相对标准偏差(RSD,n=10)在0.31%~3.4%之间。对人工合成样品及标准样品进行测试,结果与湿法测定结果吻合。 相似文献