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51.
臭氧高级氧化技术因其绿色高效、适用性广、操作简便等优势,成为当前水处理领域前沿技术之一,但臭氧在传统反应器内普遍存在吸收效果差,臭氧利用率低等缺陷。旋转填料床(RPB)利用高速旋转的填料产生超重力场,将液体剪切破碎为细小的液膜、液丝或液滴,其较高的相界面积、不断更新的界面以及内部流体的强制湍动,加快了臭氧的传质与分解,该技术对于传质受限的臭氧高级氧化过程的强化有着突出的优势。本文简述了超重力强化臭氧氧化过程的原理,介绍了RPB与O3、O3/H2O2、O3/Fenton、O3/PS(过硫酸盐)、催化臭氧氧化等高级氧化法耦合应用处理有机废水的研究现状,并对超重力技术的优势及技术突破进行了述评,总结了超重力应用臭氧高级氧化技术的潜在经济效益和环境效益,提出功能化填料及大型RPB的开发需求,以期为超重力技术在废水处理领域的拓展应用提供理论基础和技术参考。 相似文献
52.
Ball screws are crucial for improving the reliability and interchangeability of transmission mechanical systems; however, existing contact measurement methods that utilise stylus contact are not efficient, which precludes their use for rapid in-situ geometry evaluation. This paper presents a vision-based two-stage method for rapid measurement of key parameters (raceway arc radii and centre distance) of ball screws. The edge contour information is extracted from the acquired image using the dual-tree complex wavelet transform and non-maximal suppression. In the matching stage, a shape-matching algorithm is used for detecting approximate geometrical centres of raceway arcs. The refinement stage, on the other hand, is implemented for acquiring precise dimensional results. Furthermore, the method of averaging multiple measurements is performed to suppress random noise. A comparative experiment is presented to validate the robustness of the proposed method. Based on experimental results, the calculated mean absolute errors in the measurement of the two raceway arc radii and the centre distance are found to be 0.0082 mm, 0.0079 mm and 0.0055 mm, respectively. This study therefore paves the way for key parameter measurement without removing ball screws. 相似文献
53.
采用基于密度泛函的紧束缚模型(DFTB)和改进的反作用力场(ReaxFF)对全氟己酮的热分解机理进行反应分子动力学仿真研究,分析了热分解的初始反应路径、微观反应过程以及体系内气体的生成机理,探讨了温度对全氟己酮热分解的影响,建立了以仿真数据为基础的一级动力学方程并对热分解过程进行一级动力学评估。结果表明,全氟己酮热分解的起始反应为:全氟己酮→全氟异戊烷+一氧化碳,全氟己酮热分解的主要产物为一氧化碳、四氟甲烷、六氟丙烯、全氟异丁烯、十氟丁烷、全氟异戊烷及大量活性基团。经一级动力学评估得到指前因子和表观活化能分别为5.021 7×1014 s-1和1 771.96 kJ/mol。 相似文献
54.
ABSTRACTIn recent years, Wireless Sensor Networks (WSNs) are widely placed in real-time monitoring systems like environmental, structural, patient monitoring, etc. The major criterion for WSN includes energy efficiency and network lifetime. Scheduling is used as a large number of data packets focus on the same queue at the same time. Only limited data scheduling schemes have been implemented in WSN to enhance the performance. The existing First Come First Serve (FCFS) and Dynamic Multilevel Priority (DMP) have some technical challenges like delay, packet drop and high energy consumption due to starvation and deadlock. In this paper, we proposed a new algorithm to optimise and rank the incoming data packets based on multi-attributes decision-making methodology named as Packet Rank Based Data Scheduling (PRBDS), the algorithm selects packet priority, deadline, and size as the metrics to rank the incoming data packets. A simulation result shows when compared with existing scheduling, PRBDS not only provides less energy consumption, also significantly reduces the packet drop and increases the lifetime. Thus, the proposed algorithm is most suitable for real-time monitoring system since it combines data ranking method with scheduling algorithm to create accurate and reliable results to evaluate the incoming data packets. 相似文献
55.
以白云石粉为原料,利用TG、DTG、DSC联用的方法对白云石进行非等温热分解动力学研究,并进行了物相分析。结果表明,在Ar气保护和升温速率10 ℃/min的条件下,白云石的热分解是分两步进行的,第一步(CO32的扩散为控制步骤)、第二步(CO2的逸出为控制步骤)开始分解的温度分别在470、700 ℃,与纯物质的理论值相差较大;白云石的分解温度范围主要在470~590 ℃、700~820 ℃,在800 ℃时有个最大的吸热峰,此后白云石热分解吸热逐渐减小,温度达到820 ℃时失重率达到最大值45.27%,也几乎不再吸热,说明没有晶格转变在消耗能量。利用Freeman-Carroll的差减微分法对白云石非等温热分解计算分析,得到活化能E分别约为62.488、73.880 kJ/mol,指前因子A分别约为14.360、 ,两阶段的反应级数n分别约为0.490、0.819,白云石热分解过程属于相界反应模型。 相似文献
56.
57.
M. Said Ashraf A. M. Khalaf Ashraf 《International Journal of Adaptive Control and Signal Processing》2020,34(3):354-371
An electrocardiogram (ECG) signal is a record of the electrical activities of heart muscle and is used clinically to diagnose heart diseases. An ECG signal should be presented as clear as possible to support accurate decisions made by doctors. This article proposes different combinations of combined adaptive algorithms to derive different noise-cancelling structures to remove (denoise) different kinds of noise from ECG signals. The algorithms are applied to the following types of noise: power line interference, baseline wander, electrode motion artifact, and muscle artifacts. Moreover, the results of the suggested models and algorithms are compared with those of conventional denoising tools such as the discrete wavelet transform, an adaptive filter, and a multilayer neural network (NN) to ensure the superiority of the proposed combined structures and algorithms. Furthermore, the hybrid concept is based on dual, triple, and quadruple combinations of well-known algorithms that derive adaptive filters, such as the least mean squares, normalized least mean squares and recursive least squares algorithms. The combinations are formulated based on partial update, variable step-size (VSS), and second iterative VSS algorithms, which are considered in different combinations. In addition, biased NN and unbiased linear neural network (ULNN) structures are considered. The performance of the different structures and related algorithms are evaluated by measuring the post-signal-to-noise ratio, mean square error, and percentage root mean square difference. 相似文献
58.
根据水泥熟料煅烧过程操作控制原理研发的"回转窑人工智能专家系统"采用了人工智能模拟技术、实时数据清洗技术、控制数据关联匹配技术。该系统由分解炉出口温度自动控制系统、篦速自动控制系统和氨水用量自动控制系统三个模块组成。该系统投运后,分解炉出口温度控制有效率由之前人工控制的平均60%~70%提高至平均80%~95%;篦下压力和二次风温稳定性提高;氨水消耗量下降显著;窑系统投料量增加10 t/h左右,熟料标准煤耗降低2.85 kg/t,熟料强度均有提高。 相似文献
59.
Jianhuai Dong Zhixuan Dong 《International Journal of Adaptive Control and Signal Processing》2020,34(10):1466-1482
This article studies the optimal filtering and control for wireless networked control systems (WNCSs). In WNCSs, packets may be lost in both control and feedback channels and user datagram protocol is usually used to improve the performance of the real-time control. Relevant literature indicates that the conventional optimal filtering for such a system cannot be applied in practice due to the complex calculation with Gaussian mixtures. This paper proposes a novel scheme to realize the optimal filtering and the linear quadratic Gaussian control for WNCSs, in which the controlled node performs a local estimation and the remote-control node performs the final estimation and control, and a synchronization of two estimators is guaranteed by a communication mechanism. An optimal filtering algorithm is developed, the stability condition of the filtering error covariance is obtained, optimal finite-horizon and infinite-horizon control are derived, and the stability of the closed-loop control system is proved. Numerical simulations show the validity and feasibility of the theoretical results. 相似文献
60.
针对多输入多输出的广义频分复用(MIMO-GFDM)系统的等效信道矩阵维度极大,传统的MIMO检测算法复杂度高且性能不佳的问题,将大规模MIMO系统中的动态禁忌搜索(RTS)检测算法运用到MIMO-GFDM系统中,并解决了RTS算法初始值的求解复杂度高的问题。首先利用最小均方误差(MMSE)检测算法所用到矩阵的正定对称性将矩阵Cholesky分解,并结合Sherman-Morrison公式迭代计算初始值,降低了初始值求逆的高复杂度;然后以改进的MMSE检测结果作为RTS算法的初始值,从初始值逐步全局搜索最优解;最后通过仿真,对不同算法的迭代次数和误码率(BER)性能进行了研究。理论分析与仿真结果表明:在MIMO-GFDM中,所提改进RTS信号检测算法误码率远低于传统信号检测算法。在4QAM时,RTS算法大约有低于MMSE检测6 dB的信噪比性能增益(误码率在10-3时);在16QAM时,RTS算法大约有低于MMSE检测4 dB的信噪比性能增益(误码率在10-2时)。与传统RTS算法性相比,所提改进算法在不影响误码率性能的同时降低了算法复杂度。 相似文献