Ying Yu  Xiu‐Ming Dou  Bin Wei  Guo‐Wei Zha  Xiang‐Jun Shang  Li Wang  Dan Su  Jian‐Xing Xu  Hai‐Yan Wang  Hai‐Qiao Ni  Bao‐Quan Sun  Yuan Ji  Xiao‐Dong Han  Zhi‐Chuan Niu 《Advanced materials (Deerfield Beach, Fla.)》2014,26(17):2710-2717

  相似文献   

    

Yanting Ni  Yi Wang  Jin Yao  Jingmin Li 《国际生产研究杂志》2013,51(16):4805-4819

The implementation of dynamic ordering policies is becoming increasingly important for the competitiveness of modern manufacturing systems. However, existing models on dynamic ordering pay little attention to production scheduling, which greatly affects the fulfilment of dynamic ordering, especially in complex manufacturing systems. Therefore, it is imperative to establish a new model which integrates both dynamic ordering and production scheduling. Accordingly, a quantitative measurement method for integration is needed. To this end, this paper proposes a semi-finished goods delayed differentiation (SFGDD) model by taking into account integration of the scheduling inventory control and dynamic ordering simultaneously. The objective of this model is to study the relationship between the shop floor inventory and the ordering control based on the semi-finished goods dynamic dispatching mechanism. In addition, the days of inventory (DOI) and a backorder penalty exponential function are developed to quantitatively measure such a relationship. To obtain the optimal results, this paper employs a heuristic genetic algorithm (HGA) with a heuristic encoding scheme to synchronise the generation and selection of inventory variables coherently. A case study on a semiconductor assembly and test manufacturing (ATM) is presented, and a significant revenue enhancement and inventory reduction are achieved accordingly.  相似文献   

    

W. He  X. G. Ming  Q. F. Ni  W. F. Lu  B. H. Lee 《国际生产研究杂志》2013,51(9):1757-1776

Information availability is a key factor for business success and competitive advantage. While created by design engineers, product structure is accessed and referenced by other users involved in product lifecycle from various departments. However, there is a lack of efficient ways of managing product structure information for enterprise business process integration. This study proposes a unified product structure management model to fill in this gap. With this proposed model, the product structure is managed in a unified way and can be accessed by different people with various disciplines in the right formats throughout the entire product lifecycle, including business processes of quotation, sales order processing, design, planning, scheduling, production, and delivery. This research is part of the enterprise business information management system project whose purpose is to streamline the information management for key business processes to integrate multi-disciplines in an enterprise for product development. A prototype system has been implemented to verify the model developed by taking real cases in a mould-manufacturing company. The results show the potential for substantial improvements in industrial competitive advantage.  相似文献   

    

Lin Li  Qing Chang  Jun Ni 《国际生产研究杂志》2013,51(18):5019-5036

Bottlenecks within a production line significantly reduce the productivity. Quick and correct identification of the bottleneck locations can lead to an improvement in the operation management of utilising finite manufacturing resources, increasing the system throughput, and minimising the total cost of production. Most of the current bottleneck detection schemes focus on the long-term bottleneck detection problem and an analytical or simulation model is usually needed. Due to recent developments, short-term process control and quick decision making on the plant floor have emerged as important qualities for operation management. This research proposes a new data driven method for throughput bottleneck detection in both the short and long term. The method utilises the production line blockage and starvation probabilities and buffer content records to identify the production constraints without building an analytical or simulation model. The method has been verified both analytically and by simulation. An industrial case study has also been used in order to demonstrate the implementation and validate the efficiency of the proposed bottleneck detection method.  相似文献   

    

Lin Li  Saumil Ambani  Jun Ni 《国际生产研究杂志》2013,51(24):7047-7061

In the current global scenario of extreme competition, factors such as productivity, availability, quality and cost of operations play a vital role in the success of a company. A critical component relating to all of the above is maintenance. The conventional maintenance decision support systems have primarily focused on maximising the gains of a single machine system. However, a real life application usually consists of multiple machines, and the operational level decisions are more complex. In this paper, an on line plant-level maintenance decision support system (PMDSS) is developed by combining the short term and long term decision making process to improve the overall system performance while continuously attempting to maximise immediate profits in the short term. The PMDSS works towards two basic aims: (1) unplanned downtime reduction by predicting the remaining useful life of the machines, and (2) efficient utilisation of the finite maintenance and production resources through identifying the throughput-critical machines. The benefits of this approach are presented by considering an industrial case study of an automotive assembly line. The results obtained using this PMDSS approach shows a big throughput improvement as compared to the conventional maintenance policies.  相似文献   

    

Fan Niu;Tai-Li Chen;Zhi-Guo Wang;Wei Wang;Xiu-Fang Gong;Xiu-Yang Fang;Jing Ni;Zhen-Bing Cai; 《Fatigue & Fracture of Engineering Materials & Structures》2024,47(12):4478-4497

The high-temperature fretting fatigue damage characteristics of dovetail specimens strengthened by nanosecond laser (NL) and nanosecond combined femtosecond laser (F-NL) were investigated. The results show that the fretting fatigue life of the NL strengthened sample (NL sample) is improved by 211.2% compared to the base metal samples (BM sample). The lifetime of the nanosecond combined femtosecond strengthened sample (F-NL sample) was increased by 319.6%. It was attributed to the strengthening introducing hardened layers, residual compressive stress field, and high density of dislocations. The combined strengthening process reduces the surface roughness of the NL strengthened surfaces, while the strengthening influence layer is further increased. The fracture morphology shows that the crack source of the strengthened specimen has changed from multi-source sprouting to single-source sprouting, and the crack source sprouted on the subsurface. The fatigue strip morphology similarly confirms that a reduction in the crack propagation rate occurs.  相似文献   

    

Jie Wang  Yunzhou Ni  Wenfeng Jiang  Huimei Li  Yannan Liu  Shaoliang Lin  Yongfeng Zhou  Deyue Yan 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(35):4485-4490

  相似文献   

    

Xun Han  Weiming Du  Ruomeng Yu  Caofeng Pan  Zhong Lin Wang 《Advanced materials (Deerfield Beach, Fla.)》2015,27(48):7963-7969

  相似文献   

    

Tian-Yang Han  Jie Zhang  Ming-Jiu Ni 《Numerical Heat Transfer, Part A: Applications》2013,63(12):1786-1803

Abstract

The spreading characteristics of a liquid metal droplet impacting onto a flat solid surface under the influence of a horizontal magnetic field are investigated numerically. The simulated parameters are selected based on our previous experiment but over a wider range of magnetic field (0–5?T). The time evolution of the droplet shape is shown in detail and exhibits an elliptical spreading pattern, namely the droplet is stretched in the direction perpendicular to the magnet lines, which agrees well with the experimental results. To clarify the mechanism underlying the elliptical spreading pattern as well as the asymmetrical rim bulges appeared at the later stage of spreading, the current line distribution and the resultant Lorentz force at two representative times are analyzed quantitatively. The effect of the magnetic field intensity and the initial impact velocity on the anisotropic spreading of droplets is demonstrated by the maximum spreading radius and the time required to reach this maximum extent in two orthogonal directions. Finally, an energy conversion analysis of the overall spreading process is presented and the dissipation of the initial kinetic energy of droplets by Joule heat explains the inhibition effect of the horizontal magnetic field on the average spreading radius.  相似文献   

    

Meng Ni 《国际能源研究杂志》2010,34(12):1027-1041

A 2D computational fluid dynamics (CFD) model is developed to study the performance of an advanced planar solid oxide fuel cell based on proton conducting electrolyte (SOFC‐H). The governing equations are solved with the finite volume method (FVM). Simulations are conducted to understand the transport phenomena and electrochemical reaction involved in SOFC‐H operation as well as the effects of operating/structural parameters on SOFC‐H performance. In an SOFC based on oxygen ion conducting electrolyte (SOFC‐O), mass is transferred from the cathode side to the anode side. While in an SOFC‐H, mass is transferred from the anode to the cathode, which causes different velocity fields of the fuel and oxidant gas channels and influences the distributions of temperature and gas composition in the cell. It is also found that increasing the inlet gas velocity leads to an increase in the local current density and a slight decrease in the SOFC‐H temperature due to stronger cooling effect of the gas species at a higher velocity. Another finding is that the electrode structure does not significantly affect the heat and mass transfer in an SOFC‐H at typical operating voltages. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献