Lead zirconate titanate thin film capacitors on electroless nickel coated copper foils for embedded passive applications

Lead zirconate titanate (PZT, 52/48) thin film capacitors were prepared on electroless Ni coated Cu foil by chemical solution deposition for printed wiring board embedded capacitor applications. Phase development, dielectric properties, and leakage characteristics of capacitors were investigated, in particular as a function of the process temperature. Dielectric properties of the capacitors were dependent on the crystallization temperature, and capacitance densities of more than 350 nF/cm² and loss tangent of less than 0.03 were measured for capacitors crystallized below 600 °C. Lowest leakage current densities (around 2 × 10^− 7 A/cm² at 10 V direct current (DC)) and highest breakdown fields could be obtained for capacitors crystallized at 650 °C.Capacitors with different thickness and a two-layer capacitor model were used in analyzing the interface layer between PZT and the underlying electroless Ni. From the capacitance and leakage measurements, it is suggested that the interface reaction layer has low permittivity (K around 30) and high defect concentration, which has an important effect on the electrical properties of capacitors. This interface is from the reaction of the electroless nickel layer with the adjacent PZT, and may specifically be moderated by the nickel phosphide (Ni-P) phase, transformed from amorphous Ni during the annealing step.The results have significant implications for embedded capacitors in printed wiring boards. They demonstrate that the process can be tuned to produce either voltage independent capacitors with low leakage and high breakdown fields (above 30 V DC), or the more usual hysteretic, switching, ferroelectric capacitors with higher capacitance densities.     

Economic production order quantity and quality

The purpose of this study is to integrate a conventional production-inventory management approach and a process-quality design approach so as to promote quality and reduce costs. Because the integration of these two approaches into a single system is conducted under the influence of a deterioration process, estimated costs of production must be modified. Only then can these various costs be presented as a total cost for the present integrated system. This total cost includes: a setup cost for production reordering and process resetting, quality-related costs stemming from the loss of product quality along with a tolerance-related production process cost and a failure cost for product defects, backorder costs for production shortage, carrying costs generated by the storing and handling of inventory, and material costs for determining the process mean. The Taguchi quality loss function is introduced to assess quality loss in the system. The decision variables include the initial setting (process mean), process tolerance, and production order quantity. These variables need to be determined simultaneously to minimise the average total cost for a cycle time. An example is presented to demonstrate the proposed approach.     

Power plant maintenance scheduling using ant colony optimization: an improved formulation

It is common practice in the hydropower industry to either shorten the maintenance duration or to postpone maintenance tasks in a hydropower system when there is expected unserved energy based on current water storage levels and forecast storage inflows. It is therefore essential that a maintenance scheduling optimizer can incorporate the options of shortening the maintenance duration and/or deferring maintenance tasks in the search for practical maintenance schedules. In this article, an improved ant colony optimization-power plant maintenance scheduling optimization (ACO-PPMSO) formulation that considers such options in the optimization process is introduced. As a result, both the optimum commencement time and the optimum outage duration are determined for each of the maintenance tasks that need to be scheduled. In addition, a local search strategy is presented in this article to boost the robustness of the algorithm. When tested on a five-station hydropower system problem, the improved formulation is shown to be capable of allowing shortening of maintenance duration in the event of expected demand shortfalls. In addition, the new local search strategy is also shown to have significantly improved the optimization ability of the ACO-PPMSO algorithm.     

Assessing the utility of environmental factors and objectives in environmental impact assessment practice: Western Australian insights

Environmental factors and objectives are formally identified during the scoping stage of environmental impact assessment (EIA) to structure and focus individual assessments. Environmental factors are broad components of the environment, while objectives set the desired outcome for a specific factor. This research assesses the utility of environmental factors and objectives in EIA practice based upon a combination of literature review and interviews with 21 EIA practitioners from Western Australia. Further to providing focus and structure for EIA, practitioners also use environmental factors and objectives for decision-making throughout the process. The majority of practitioners also note that factors and objectives are value adding and useful to their EIA practice. Due to their inherent subjective natures, interviewees noted a lack of consistency regarding how to meet the objectives and challenges in determining the significance of impacts on a factor. Identified opportunities to enhance use of objectives and factors in EIA included provision of more guidance, especially criteria or standards to apply and improve knowledge sharing between EIA stakeholders.     

XPS investigation of a CdS-based photoresistor under working conditions: operando-XPS

A noncontact chemical and electrical measurement X-ray photoelectron spectroscopy (XPS) technique is performed to investigate a CdS-based photoresistor during its operation. The main objective of the technique is to trace chemical- and location-specified surface potential variations as shifts of the XPS Cd 3d(5/2) peak position without and under photoillumination with four different lasers. The system is also modeled to extract electrical information. By analyzing the measured potential variations with this model, location-dependent resistance values are represented (i) two dimensionally for line scans and (ii) three dimensionally for areal measurements. In both cases, one of the dimensions is the binding energy. The main advantage of the technique is its ability to assess an element-specific surface electrical potential of a device under operation based on the energy deviation of core level peaks in surface domains. Detection of the variations in electrical potentials and especially their responses to the energy of the illuminating source in operando, is also shown to be capable of detecting, locating, and identifying the chemical nature of structural and other types of defects.     

Measurement selection for parametric IC fault diagnosis

This article presents experimental results which show feedforward neural networks are well-suited for analog IC fault diagnosis. Boundary band data (BBD) measurement selection is used to reduce the computational overhead of the FFN training phase. We compare the diagnostic accuracy between traditional statistical classifiers and feedforward neural networks trained with various measurement selection criteria. The feedforward networks consistently perform as well as or better than the other classifiers in term of accuracy. Training using BBD consistently reduces the FFN training efforts without degrading the performance. Experimental results suggest that feedforward networks provide a cost efficient method for IC fault diagnosis in a large scale production testing environment.This work is supported by NSF-IUC CDADIC, Project 90-1.     

What is being masked in object substitution masking?

Object substitution masking (OSM) is said to occur when a perceptual object is hypothesized that is mismatched by subsequent sensory evidence, leading to a new hypothesized object being substituted for the first. For example, when a brief target is accompanied by a longer lasting display of nonoverlapping mask elements, reporting of target features may be impaired. J. T. Enns and V. Di Lollo (2000) considered it an outstanding question whether OSM masks some or all aspects of a target. The authors report three experiments demonstrating that OSM can selectively affect target features. Participants may be able to detect a target while being unable to report other aspects of it or to report the color but not the orientation of a target (or vice versa). We discuss these findings in relation to two other visual phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)