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本文提出了一种基于logistic映射的混沌TPWM(CTPWM)方法,并采用M37705单片机实现。给出了该映射的统计特征分析和量化实现。大量实验表明,与传统的PWM方法相比,CTPWM在较低载波频率情况下具有低噪音及较好的谐波特性。采用CTPWM方法成功地开发了低成本高性能洗衣机变频调速器。 相似文献
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对PDP清洗工艺的探索 总被引:2,自引:0,他引:2
本文介绍了用于21英寸PDP清洗的工艺流程及解决各种对清洗质量造成影响的因素的办法。 相似文献
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金在新一轮找矿突破战略行动矿产分析中占有重要的地位,采用活性炭动态富集-火焰原子吸收光谱法测定岩石矿物样品中金的分析方法已被广泛应用。然而其分析条件的影响因素较多,在测定过程中活性炭的用量、灰分的大小、吸附层的设计以及洗涤液溶液温度等因素对测定结果的准确性具有重要影响。试验分别以活性炭用量、不同灰分值、吸附层数以及洗涤溶液的温度为变量,对金分析标准物质GBW(E)070013b、GBW07297a、GBW07299a、GBW07810进行实验对比分析。结果表明,金的回收率随着活性炭用量的增加而不断提升,在0.5g后趋于稳定;活性炭灰分值越大,金元素损失越多,当灰分值小于0.05%时,回收率趋于稳定,接近99%;活性炭吸附层设计为双层和三层时,测定值的平均值与认定值的相对偏差(RE/%)和相对标准偏差(RSD/%,n=6)分别为0.14%~3.22%和0.04%~3.68%,优于混合层和单层,满足岩石矿物质控标准规范中正确度和精密度的要求;抽滤洗涤热溶液(70℃~80℃)时,金矿石标准物质金元素的平行样的准确度和相对标准标准偏差最小,均小于2.1%,通过方法验证,测定金的正确度精密度(RSD,n=6)分别小于0.76%和3.78%,满足DZ/T 0130.3-2006《地质矿产实验室测试质量管理规范》中岩石矿物样品化学成分分析的质量要求。该方法优化了活性炭吸附测金的试验条件,试验方法的正确度和精密度均满足要求,能满足金矿石中金的准确测定。 相似文献
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In this paper, a novel and precise analytical procedure has been developed for quantitative determination of sodium percarbonate (SPC) in washing powder. The method is based on the partial least squares (PLS) treatment of data obtained by attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectrometry in wavenumber region of 1435-1342 cm−1. The statistical parameters such as R2, RSD, SEC and SECV have been evaluated, and number of factors, number of scan and the resolution have been optimized. In this method R2 and RSD for five independent analyses of a 0.552 g per 100 g solution of SPC, SEC for 10 standard samples and SECV for five validation samples were 0.998, 1.011, 0.002 and 0.039 respectively.Results obtained for six different commercial washing powders compared well with those obtained with a standard method. 相似文献
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Carboxymethylcellulose (CMC) was prepared from nine commercial dissolving pulps with different origins, viscosities and S18-values. The rate of the etherification reaction and the final DS were studied with respect to the influence of pulp composition,
pulp viscosity and S18-value, and with respect to the sodium hydroxide and sodium monochloro-acetate charges. The possible influence on the final
DS-value of the CMC of the washing procedure after the etherification was also investigated. 相似文献