排序方式: 共有23条查询结果,搜索用时 31 毫秒
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铝电解车间具有高温、强磁、多粉尘等环境特点,当前生产过程中熔融原铝的成分检测主要是人工取样然后离线分析,化验过程及结果具有较大的滞后性,故将激光诱导击穿光谱(LIBS)技术应用于铝电解车间铝液成分原位、实时测量具有重要意义。实验采用Nd:YAG脉冲激光器,多通道光纤光谱仪和电感耦合器件(CCD)探测器组成的激光诱导击穿光谱测量系统对电流为400kA电解槽中熔融铝液的主要成分铁、硅进行了探测,对原铝中部分元素的特征谱线进行了归属分析。考察了激光能量在磁场环境下的衰减变化及谱线梯度变迁规律,结果表明,距离电解槽边缘约2m处激光能量衰减达最大。分析了磁场对测试系统的影响,并建立了定标曲线,铁和硅两种元素按照内标法建立的定标曲线拟合度分别为93.50%和97.10%,采用该模型进行了测试实验,并用国标GB/T 7999—2015中光电直读发射光谱(OES)测试的相关指标验证测试结果的重复性与允许差。实验证明,LIBS技术在电解铝行业在线检测方面具有较好的应用前景,但是测试的稳定性与重复性也是面临的一个重要问题。 相似文献
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废旧金属回收是工业中金属的重要来源之一,是发展循环经济的重要内容。废旧金属产量巨大,通常表面覆盖杂质,凹凸不平,因此对分类方法的判别能力和计算速度提出较高要求。采用激光诱导击穿光谱技术研究分析了7种废旧金属分类识别问题,包括生铝、熟铝、镁、不锈钢、锌、黄铜与红铜。为了符合现场应用条件,实验中每个样本点只激发一次建立并分析了多种分类模型,包括支持向量机(SVM)分类模型,主成分分析方法结合支持向量机(PCA-SVM)分类模型,遗传算法结合支持向量机(GA-SVM)分类模型,遗传算法选择特征光谱结合主成分分析方法和支持向量机(GA-PCA-SVM)分类模型,以及遗传算法选择特征光谱结合主成分分析方法和人工神经网络(GA-PCA-BP)分类模型。通过遗传算法选取包含丰富特征的谱段组合与支持向量机方法相结合建立GA-SVM分类模型,490组验证样本分类准确率为93.47%。为了判断该模型的鲁棒性,对一批新样品,在自研的分选系统上以传送带匀速运行的方式进行测试,获取的750组光谱测试数据,分类准确率为88.27%,证明了该分类模型具有很好的移植性和应用性。 相似文献
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KONG Haiyang 《等离子体科学和技术》2015,17(11):964-970
Principal component analysis (PCA) combined with artificial neural networks was used to classify the spectra of 27 steel samples acquired using laser-induced breakdown spec?troscopy. Three methods of spectral data selection, selecting all the peak lines of the spectra, selecting intensive spectral partitions and the whole spectra, were utilized to compare the influ?ence of different inputs of PCA on the classification of steels. Three intensive partitions were selected based on experience and prior knowledge to compare the classification, as the partitions can obtain the best results compared to all peak lines and the whole spectra. We also used two test data sets, mean spectra after being averaged and raw spectra without any pretreatment, to verify the results of the classification. The results of this comprehensive comparison show that a back propagation network trained using the principal components of appropriate, carefully se?lected spectral partitions can obtain the best results. A perfect result with 100% classification accuracy can be achieved using the intensive spectral partitions ranging of 357-367 nm. 相似文献
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本文就思维问题作了简要说明,举例说明了培养学生创造性思维能力的方法,还提出了培养学生创造性思维能力的几个关键点。 相似文献
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孙兰香 《甘肃水利水电技术》2004,40(3):244-245
综合自动化系统作为一门新兴技术 ,其功能还有待于不断扩充和完善。针对目前变电站综合自动化系统设计 ,提出了一些值得注意的问题 ,结合工程实际进行了探讨 ,总结出了解决方法 相似文献
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基于激光诱导击穿光谱的钢液成分在线监视 总被引:2,自引:0,他引:2
基于激光诱导击穿光谱(LIBS)技术对钢液中的Cr,Si和Mn 3种元素成分进行浓度在线监视。实验采用中频感应炉熔炼钢材,并在熔炼过程中添加一定量的添加料调整成分。采用研发的SIA-LIBS-02实验系统对炉中的钢液进行直接测量,研究了钢液温度和元素浓度对谱线强度的影响。结果表明,钢液温度对元素特征谱强影响严重,而且不同元素的谱强随温度变化不同,钢液中微量元素的检出能力要高于常温固态钢样;采用相对谱线强度能够补偿在线测量过程中的动态干扰,在保持钢液温度一致的情况下,能够成功在线监视钢液中Cr,Si和Mn元素的浓度变化。 相似文献
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Peng ZHANG 《等离子体科学和技术》2022,24(8):84006
The concentrations of SiO2, Al2O3, K2O, Na2O, CaO, MgO, Fe2O3 and TiO2, and loss on ignition (L.O.I.) are the main inorganic components of geological samples. Concentrations of the eight oxides and L.O.I. are also the main indicators of concern in the production of building ceramics. Quantitative analysis of the eight oxides and L.O.I. was performed using fiber-laser-based laser-induced breakdown spectroscopy (LIBS). A combination of continuous background deduction, full width at half maximum (FWHM) intensity integral and spectral sum normalization was proposed for data processing. After the data processing combined the continuous background deduction, FWHM intensity integral and spectral sum normalization, the mean absolute errors (MAEs) of the calibration of L.O.I., SiO2, Al2O3, K2O, Na2O, CaO, MgO, Fe2O3 and TiO2 was reduced from 2.03%, 12.06%, 4.84%, 1.10%, 0.69%, 0.31%, 0.11%, 0.20% and 0.10% to 1.80%, 9.48%, 2.12%, 0.36%, 0.58%, 0.11%, 0.08%, 0.19% and 0.05%, respectively. This multivariate method was further introduced and discussed to improve the analysis performance. The MAEs of L.O.I., SiO2, Al2O3, K2O and Na2O were further reduced to 1.12%, 2.07%, 1.38%, 0.35% and 0.43%, respectively. The results show that the overall prediction error can meet the requirements for the production of building ceramics. The LIBS desktop analyzer has great potential in detection applications on geological samples. 相似文献
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参数时变系统可以通过增广状态法转换成一种标准形式.本文应用极点配置设计法,设计了基于网络控制系统标准形式模型的控制规律和观测器,并证明了分离定理仍然成立.仿真研究表明该设计方法应用到网络控制系统的有效性. 相似文献