基于氧化锆传感器的氧含量校正及接口电路设计

通过对氧含量测量的现实意义的探讨,以及目前应用较为广泛的氧化锆传感器相关原理的研究,介绍了一种对由氧化锆传感器测得的电压信号进行一系列数据处理,除去误差影响,计算出所需要的待测气体准确的氧体积含量步骤的方法,最后给出传感器与MCU接口电路的硬件设计。     

一种准确简便地标定氧化锆氧量分析仪的新方法

本文提出仅用一种标准气或不用标准气标定氧化锆氧量分析仪的新方法。它符合我国的相关检定规程,适宜含氧量下限不小于0．1％的氧量分析仪的首次检定、后续检定和使用中的检验,尤其适宜在发电厂使用了较长时间后,对“检测器的多孔陶瓷过滤网已破损或其气孔被堵塞程度不明”的情况下进行检定或标定。     

Strategies for electrosynthesis of poly(vinylbenzyltrimethylammonium chloride) and composite films

Poly(vinylbenzyl trimethyl ammonium chloride) (PVT) exhibits functional properties, which have generated interest in the fabrication of PVT and composite films. New electrochemical strategies have been utilized for the deposition of PVT-zirconia composites. The problems, related to the electrodeposition of strong polyelectrolytes, such as PVT, were addressed by the development of charge compensation mechanisms. The deposition strategies involved electrophoretic cathodic deposition (EPD) of PVT and EPD or electrochemical synthesis of zirconia. The proof of concept investigations involved deposition yield studies under different conditions, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and electron microscopy studies. The electrochemical strategies can be used for electrodeposition of various composites, utilizing the properties of functional polymers and inorganic materials.     

Multi-response optimization of the electrical discharge machining of insulating zirconia

In this study, electrical discharge machining has been used to machine insulating zirconia via the assisting electrode method. The process parameter optimization was investigated by combining the Taguchi method with grey relational analysis. The application of Taguchi–grey relational analysis is proven to effectively improve the performance of electrical discharge machining in drilling insulating zirconia. The results of this analysis indicate that the final optimal process parameters are a peak current of 8 A, a pulse duration of 16?µs, a duty cycle of 0.5, and a flushing pressure of 6?MPa. Additionally, the material removal rate, electrode wear rate, and hole taper ratio increase by 39%, 1.5%, and 1.3%, respectively, which improves the grey relational grade by 6.8%. The electrical resistance test confirms that the conductivity of the conductive layer obtained using the final optimal process parameters is better than that of the conductive layer obtained using the initial optimal process parameters. Energy spectrum analysis reveals that the conductive layer is composed of C, Cu, Zn, Zr, and O. Analysis of variance shows that the most significant component of the multi-responses is the peak current, with a 51.4% contribution.     

Cyclic Nanoindentation for Local High Cycle Fatigue Investigations: A Methodological Approach Accounting for Thermal Drift

Cyclic nanoindentation allows characterizing the influence of single phases and their interactions on fatigue mechanisms. Herein, a method for high cycle fatigue testing by nanoindentation is presented. By combining high- and low-frequency indentation modes, high cycle numbers are achieved while obtaining sufficient data points to reconstruct force–displacement hysteresis loops. A challenge is the stochastic course of thermal drift which is addressed by measuring drift rate in regular low-force holding segments. Drift rates are used to correct the displacement values, yielding reproducible cyclic deformation data as it is shown for two very different materials, a ductile metal and a brittle ceramic.     

Pentane isomerization and disproportionation catalyzed by sulfated zirconia promoted with iron and manganese

Fe- and Mn-promoted sulfated zirconia was used to catalyze the conversion ofn-pentane in a flow reactor at temperatures in the range of –25 to 40C andn-pentane partial pressures in the range of 0.005 to 0.01 atm. The rates of reaction increased with time on stream during an induction period and then decreased rapidly. The predominant reaction at –25C and short times on stream was isomerization to give isopentane; no dibranched products were observed. The selectivity for isomerization decreased and that for disproportionation increased with increasing temperature, with disproportionation becoming predominant at 40C; the principal product was then isobutane. The product distribution data are consistent with acid-base catalysis and carbocation intermediates. However, there appears to be more to the reaction mechanism than acid-base chemistry, and the roles of the iron and manganese promoters are not yet explained.     

基于SIMD部件的四倍精度浮点乘加器设计

如何减少四倍精度浮点运算的硬件开销和延迟是需要解决的重要问题。为减少四倍精度乘加器的硬件开销,基于支持64位×4的双精度浮点SIMD FMA部件,设计并实现了一种新的四倍精度浮点乘加器(QPFMA),来支持4种浮点乘加运算和乘法、加减法、比较运算,运算延迟为7拍。通过将四倍精度113位×113位尾数乘法器分解为4个57位×57位乘法器来共享双精度浮点SIMD FMA部件的53位×53位乘法器,显著减少了实现QPFMA的硬件开销。基于65nm工艺的逻辑综合结果表明,该QPFMA频率可达1.1GHz,面积是常规QPFMA设计的42.71％,仅与一个双精度浮点乘加器相当。与现有的QPFMA设计相比,相当工艺和频率下,其运算延迟减少了3拍,门数减少了65.96％。     

基于BP神经网络的氧化锆氧量计的非线性补偿研究

氧化锆氧量计的工作原理是氧浓差电池原理,其氧浓差电势的计算是严重的非线性函数;选用只含一个隐含层的三层BP神经网络结构,充分利用BP神经网络的非线性函数逼近能力,无需模型只要适量的学习样本通过反复训练,即可按指定精度完成对氧化锆氧量计非线性特性的辩识和输出信号的非线性补偿;就隐含层节点数、学习率、误差指标等参数对该方法中BP神经网络训练次数和收敛过程的影响进行了比较研究。     

Effect of magnesium and nickel coatings on the wetting behavior of alumina toughened zirconia by molten Al-Mg ahoy

The wettability of alumina toughened zirconia (ZTA) by Al-Mg alloy was investigated using the sessile drop technique.The effects of nickel coating,magnesium content,nitrogen atmosphere,and processing temperature on the contact angle between the molten alloy and the substrate were determined.Likewise,the effect of these factors on the wetting properties was studied.The results showed that the nickel coating on the ceramic substrate caused a significant reduction in solid/liquid surface energy and the contact angle decreased obviously.The presence of magnesium in the molten aluminum alloy in nitrogen atmosphere reduced the contact angle effectively.The presence of magnesium in the alloy must be at a minimum amount of 2wt％-3wt％.Moreover,it was suggested that some chemical reactions in the Al-Mg-N system led to the production of Mg3N2 and A1N compositions.These compositions improved the wetting properties of the systems by reducing the surface energy of the molten.It was shown that increasing the temperature is also an effective factor for the enhancement of wetting properties.