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Fabrication of different shapes of tool electrodes using a variable-parameter bipolar-pulsed liquid membrane electrochemical etching method

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JOURNAL OF MATERIALS PROCESSING TECHNOLOGY 2025年 339卷

作者： Wu, Xiujuan Wang, Li Yang, Tao Kong, Weijing Hang, Yusen Zeng, Yongbin Nanjing Vocat Univ Ind Technol Coll Mech Engn Nanjing 210023 Peoples R China Nanjing Univ Aeronaut & Astronaut Coll Mech & Elect Engn Nanjing 210016 Peoples R China

With traditional liquid membrane electrochemical etching methods, it is difficult to effectively control the electrolytic products. In this paper, a variable-parameter bipolar-pulsed liquid membrane electrochemical etching technique is proposed for the preparation of microelectrodes. The introduction of negative voltage will generate insoluble electrolytic products on the electrode surface. By adjusting the processing parameters, these electrolytic products can be precisely controlled, thereby shaping the morphology of the electrodes. In step one, the positive voltage is larger and the electrode surface is coated with a layer of insoluble electrolytic products. In step two, the positive voltage is smaller and hydrogen is generated on the electrode surface, dispersing the electrolytic products. The effects of positive voltage, negative voltage and processing time on the distribution of electrolytic products and electrode morphology were investigated in different steps. It was found that the upper and lower electrodes changed significantly with the change of processing time. Based on the experimental results, the droplet-shaped upper electrode and conical-shaped lower electrode with tiny size and controllable shape were prepared. In addition, a repeated-variable-parameter method was used to mitigate the problem of inconsistent etching speed that was caused by the electrolytic product coating, and enabled the preparation of cylindrical electrodes that are uniform in size. While keeping the processing mode unchanged, different shaped electrodes can be manufactured by simply adjusting the parameters to control the distribution of electrolytic products, demonstrating good processing flexibility.

关键词： Bipolar pulse Electrochemical etching variable parameter Micro-tool electrode

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variable parameter and double sampling (X)over-bar charts in the presence of correlation: The Markov chain approach

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INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS 2011年第2期130卷 224-229页

作者： Branco Costa, Antonio Fernando Guerreiro Machado, Marcela Aparecida Sao Paulo State Univ UNESP Prod Dept Guaratingueta SP Brazil

The general assumption under which the (X) over bar chart is designed is that the process mean has a constant in-control value. However, there are situations in which the process mean wanders. When it wanders according to a first-order autoregressive (AR (1)) model, a complex approach involving Markov chains and integral equation methods is used to evaluate the properties of the (X) over bar chart. In this paper, we propose the use of a pure Markov chain approach to study the performance of the (X) over bar chart. The performance of the chat (X) over bar with variable parameters and the (X) over bar with double sampling are compared. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Markov chain (X)over-bar chart Correlation variable parameter Double sampling

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variable parameter sliding controller design for vehicle brake with wheel slip

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JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY 2006年第11期20卷 1801-1812页

作者： Liang, Hong Chong, Kil To Chonbuk Natl Univ Fac Elect & Informat Chonju 561756 South Korea

In this paper, a 4-wheel vehicle model including the effects of tire slip was considered, along with variable parameter sliding control, pushrod force as the end control parameter, and an antilock sliding control, in order to improve the performance of the vehicle longitudinal response. The variable sliding parameter is made to be proportional to the square root of the pressure derivative at the wheel, in order to compensate for large pressure changes in the brake cylinder. A typical tire force-relative slip curve for dry road conditions was used to generate an analytical tire force-relative slip function, and an antilock sliding control process based on the analytical tire force-relative slip function was used. A retrofitted brake system, with the pushrod force as the end control parameter, was employed, and an average decay function was used to suppress the simulation oscillations. Simulation results indicate that the velocity and spacing errors were slightly larger than the results that without considering wheel slip effect, the spacing errors of the lead and follower were insensitive to the adhesion coefficient up to the critical wheel slip value, and the limit for the antilock control on non-constant adhesion road condition was determined by the minimum of the equivalent adhesion coefficient.

关键词： automatic highway vehicles wheel slip antilock control sliding control variable parameter smoothing

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variable parameter Uzawa method for solving the indefinite least squares problem

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NUMERICAL ALGORITHMS 2024年第2期99卷 1043-1061页

作者： Meng, Lingsheng Xin, Kailiang Li, Jun Northwest Normal Univ Coll Math & Stat Lanzhou 730070 Peoples R China Lanzhou Univ Technol Sch Sci Lanzhou 730050 Peoples R China

In this paper, the variable parameter Uzawa method is presented to solve the indefinite least squares problem. The proposed iterative method is unconditionally convergent, and its iterative algorithm and parameter designing are simple and efficient. Numerical experiments show that the variable parameter Uzawa method is superior to the USSOR method (Song, Int. J. Comput. Math. 97, 1781-1791 2020) and the splitting-based randomized iterative method (Zhang and Li, Appl. Math. Comput. 446, 127892 2023).

关键词： Indefinite least squares problem variable parameter Uzawa method Convergence Minimize norm

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variable parameter Uzawa method for solving a class of block three-by-three saddle point problems

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NUMERICAL ALGORITHMS 2020年第4期85卷 1233-1254页

作者： Huang, Na China Agr Univ Coll Sci Dept Appl Math Beijing Peoples R China

In this work, we consider numerical methods for solving a class of block three-by-three saddle point problems, which arise from finite element methods for solving time-dependent Maxwell equations and a class of quadratic programs. We present a variant of Uzawa method with two variable parameters for the saddle point problems. These two parameters can be updated easily in each iteration, similar to the evaluation of the two iteration parameters in the conjugate gradient method. We show that the new iterative method converges to the unique solution of the saddle point problems under a reasonable condition. Numerical experiments highlighting the performance of the proposed method for problems are presented.

关键词： Saddle point problem Uzawa iterative method variable parameter

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Rating Curve Development at Ungauged River Sites using variable parameter Muskingum Discharge Routing Method

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WATER RESOURCES MANAGEMENT 2014年第11期28卷 3783-3800页

作者： Sahoo, Bhabagrahi Perumal, Muthiah Moramarco, Tommaso Barbetta, Silvia Indian Inst Technol Sch Water Resources Kharagpur 721302 W Bengal India Indian Inst Technol Roorkee Dept Hydrol Roorkee 247667 Uttar Pradesh India CNR Ist Ric Protez Idrogeol Perugia Italy

A physically based simplified discharge routing method, namely, the variable parameter Muskingum discharge-hydrograph (VPMD) routing method, having the capability of estimating the stage hydrographs simultaneously in channels with floodplains is presented herein. The upstream discharge hydrograph is routed using this VPMD method in different two-stage symmetrical trapezoidal compound cross section channel reaches. The performance of the VPMD method is evaluated by numerical experiments using the benchmark MIKE11 hydrodynamic model and the field data of the Tiber River in central Italy. The proposed method is capable of accurately routing the discharge hydrographs, corresponding stage hydrographs and synthesizing the normal rating curves at any downstream ungauged river site which is not affected by any downstream effects. This study can be helpful for various planning and management of river water resources in both the diagnostic and prognostic modes.

关键词： Hydrograph Rating curve Routing Ungauged river variable parameter VPMD routing method

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Vehicle longitudinal brake control using variable parameter sliding control

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CONTROL ENGINEERING PRACTICE 2003年第4期11卷 403-411页

作者： Liang, H Chong, KT No, TS Yi, SY Chonbuk Natl Univ Reg Res Ctr Duckjin Gu Chonju 561756 South Korea

A modified sliding control with variable control parameter was introduced to reduce the large change of pressure feedback in the hydraulic brake control process of automated highway vehicles. An average decay function was used to smooth both high and low frequency oscillations of the desired diaphragm force and output force in the vacuum booster to remedy the oscillations generated by using the pushrod force as the end-brake control. Simulation results indicate that the variable parameter sliding control significantly reduces the speed and space tracking errors in the large brake processes, and the errors experienced during these processes are dominated by the large brake pressure lag rather than the switching delay time between throttle and brake. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词： automatic highway vehicles brake control sliding control variable parameter smoothing

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A fully mass conservative variable parameter McCarthy-Muskingum method: Theory and verification

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JOURNAL OF HYDROLOGY 2013年 502卷 89-102页

作者： Perumal, Muthiah Price, Roland K. Indian Inst Technol Roorkee Dept Hydrol Roorkee 247667 Uttar Pradesh India Inst Water Educ UNESCO IHE NL-2601 DA Delft Netherlands

This paper presents the hydraulic derivation of a fully mass conservative, variable parameter McCarthy-Muskingum (VPMM) method derived directly from the Saint-Venant equations for routing flood waves in prismatic channels having any cross-section shape, and using the Manning's friction law. The approach employed in the development of the method theoretically justifies the heuristic assumption made by McCarthy in 1938 in expressing the channel reach storage of the Muskingum method in terms of prism and wedge storages. The approach advocated in this paper also provides a solution to the mass conservation problem associated with the variable parameter Muskingum routing method, which has been a major issue in the hydrological literature for the last three decades. Moreover, the VPMM method enables the simultaneous computation of the stage hydrograph corresponding to a given inflow or routed discharge hydrograph. The verification of the methodology and the evaluation of its performance in routing floods in three different shapes of a hypothetical channels are presented by reproducing the corresponding numerical solutions of the Saint-Venant equations. The results are also compared with the corresponding results of the mass conservative variable parameter Muskingum-Cunge-Todini method proposed by Todini in 2007 with and without the inclusion of the correction introduced by Cappelaere in 1997 for diffusion. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Hydrograph Routing variable parameter Muskingum routing method

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Periodic solutions for generalized Lienard neutral equation with variable parameter

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NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS 2009年第6期70卷 2387-2394页

作者： Du, Bo Guo, Lixiang Ge, Weigao Lu, Shiping Beijing Inst Technol Dept Math Beijing 100081 Peoples R China Anhui Normal Univ Dept Math Wuhu 241000 Peoples R China

By means of Mawhin's continuation theorem, existence criteria is established for the periodic solutions to a neutral equation with variable parameter. It is worth stating that the coefficient c is not a constant, ... 详细信息

关键词： Neutral variable parameter Periodic solution Mawhin's continuation theorem

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A variable parameter bidirectional stage routing model for tidal rivers with lateral inflow

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JOURNAL OF HYDROLOGY 2018年 564卷 1036-1047页

作者： Zhang, Xiaoqin Bao, Weimin Liang, Wenqing Shen, Dandan Hohai Univ Coll Hydrol & Water Resources Nanjing 210098 Jiangsu Peoples R China Hohai Univ Natl Cooperat Innovat Ctr Water Safety & Hydrosci Nanjing 210098 Jiangsu Peoples R China Jiangsu Water Source Co Ltd Eastern Route South North Water Divers Project Nanjing 210029 Jiangsu Peoples R China

Water stage variations are complicated in tidal rivers due to the combination of upstream flood and downstream tide. This study proposed a bidirectional stage routing model (BSR) for tidal rivers by considering the stage hydrograph as the overlay of bidirectional propagation of upstream flood wave and downstream tidal wave. The basic stage routing equations derived from the storage equation and water balance equation are used to calculate the upstream flood wave routing and the downstream tidal wave propagation, respectively. The lateral inflow can be directly specified as an additive term in the basic equation of BSR model or indirectly estimated by a lateral flow rate reflecting the proportion of lateral inflow to the upstream water. Parts of the model parameters are time-variable to account for the effect of water surface slope on water stage. The model inputs include stage hydrographs at the upstream and downstream boundaries. The channel geometric characteristics data are not required when the average channel width is estimated as a parameter. The case study results in the tidal reaches of the Caoe River and Qiantang River in China demonstrate that the BSR model performs well in water stage simulation. With relatively simple structure, modest data requirement and stable performance, the physically-based BSR model has the potential for water stage routing in tidal rivers when channel geometry data are not available.

关键词： Water stage routing Tidal river Bidirectional propagation Lateral inflow variable parameter

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