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提出了机械制图类课程教学应以实用为主和强化培养学生实际能力为原则,主张打破传统的教材体制,按需要精简教学内容,科学设置教学方法,强化学生的技能训练。 相似文献
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High repetition rate laser-ablation spark-induced breakdown spectroscopy(HRR LA-SIBS) was first used to analyze trace elements in copper alloy samples. The 1064 nm output of an acoustooptically Q-switched Nd:YAG laser operated at a pulse repetition rate of 1 kHz was utilized to ablate copper alloy and to form original plasma, spark-discharge was applied to further breakdown the ablated samples and enhance the emission of the laser-induced plasma. A compact multichannel fiber spectrometer was used to analyze the plasma emission under nongated operation mode. Under the assistance of high repetition rate spark discharge, the plasma emission was able to be improved significantly. The determined limits of the detection of lead and aluminum were 15.5 ppm and 1.9 ppm by HRR LA-SIBS, respectively, which were 11 and 6 folds better than that determined by HRR LIBS under the same laser-ablation condition. This work demonstrates the feasibility of using fiber spectrometer to analyze plasma emission under non-gated operation mode and the possibility of building a portable HRR LA-SIBS system for rapid elemental analysis of copper alloys and other solid samples. 相似文献
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为了对烟草行业价格满意度进行优化和评价,提出了客户价格满意度的基本思想,在简要阐述模拟退火神经网络(BPSA)算法的基础上建立客户价格满意度的非线性模型,并通过BPSA算法实现之。然后对某烟草公司价格满意度的相关数据进行了提取、优化、对比和分析,结果证明,BPSA算法局部加快了学习的收敛速度,克服了BP算法的局限性,能够在客户价格满意度中得到最小极值点区间,是一种行之有效的处理方法,在客户价格满意度方面具有一定的应用价值。 相似文献
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