ATTRIBUTES FOR EXPEDIENT COMPUTER VISION INSPECTION

The visual inspection of parts as they progress through die manufacturing process is an important task in all industries. Visual inspection, when performed by humans is a tedious task and is prone to error. This is precisely what makes it a good candidate for automation. Although computer vision systems have been around for over 30 years, die industrial applications of vision systems have become practical only in die last decade. Image processing and pattern recognition algorithms used in industrial vision systems are built upon a broad body of knowledge in vision research. But the use of computer vision systems in quality control has been limited to replicating die visual inspection tasks as they would be performed by a human operator. It is die contention of this study that when computerized inspection is employed, quality control inspection plans suitable for computerized inspection should also be employed to assure cost-effectiveness.

We study a simple gauging inspection task and propose a quality control plan that exploits die characteristics of computer vision systems in order to improve cost-effectiveness.     

用溶胶—凝胶法制备[（Pb,La）（Zr,Ti）O3]铁电薄膜

利用溶胶－凝胶法制备了［Ｐｂ，Ｌａ）（Ｚｒ，Ｔｉ）Ｏ３］铁电薄膜。利用ＤＴＡ－ＴＧ，ＸＲＤ和ＳＥＭ研究了［（Ｐｂ，Ｌａ）（Ｚｒ，Ｔｉ）Ｏ３］凝胶的分解、晶化过程［（Ｐｂ，Ｌａ）（Ｚｒ，Ｔｉ）Ｏ３］薄膜的显微形貌。为了获得致密无龟裂的［（Ｐｂ，Ｌａ）（Ｚｒ，Ｔｉ）Ｏ３］薄膜，应使用具有适当粘度的前体溶胶，这是通过控制其浓度和水解度来获得的。     

Fully integrated on-chip electrochemical detection for capillary electrophoresis in a microfabricated device

Microfabricated lab-on-a-chip devices employing a fully integrated electrochemical (EC) detection system have been developed and evaluated. Both capillary electrophoresis (CE) channels and all CE/EC electrodes were incorporated directly onto glass substrates via traditional microfabrication techniques, including photolithographic patterning, wet chemical etching, DC sputtering, and thermal wafer bonding. Unlike analogous CE/EC devices previously reported, no external electrodes were required, and critical electrode characteristics, including size, shape, and placement on the microchip, were established absolutely by the photolithography process. For the model analytes dopamine and catechol, detection limits in the 4-5 microM range (approximately 200 amol injected) were obtained with the Pt EC electrodes employed here, and devices gave stable analytical performance over months of usage.     

Reduced Order Modeling of Interconnected Multimachine Power Systems Using Time-Scale Decomposition

Time-scale decomposition is used to systematically produce improved reduced order models of interconnected multimachine power systems. The method is illustrated with two fundamental examples. The first shows that the I = YV interface equation used for studying multimachine electromechanical transients is a zero order representation of the fast network transients. As such, the time-scale theory can be used to produce improved electromechanical models without adding the network transient equations. The second example shows how linear models for small change stability analysis can be improved to virtually any degree of accuracy. The advantages of the improved models are shown with both a two- and three-machine system.     

Analysis of tubular linear induction motors, using the concept of surface impedance

By using the surface-impedance method, equivalent circuit for an axial-flux tubular induction motor is obtained. This circuit is used to determine the performance characteristics of a laboratory model. The calculated results are compared with experimental results. The voltages and currents in the equivalent circuit are related directly to the field quantities within the actual device.     

Electrical resistivity studies on acid-treated E-glass fabric

E-glass fabrics were soaked in 0.1 to 2N hydrochloric acid for 0.5 to 3 h to remove the non-siliceous ions, and the volume resistivity of the treated fabrics was measured using d.c. voltages of 100, 250, 400 and 500. The electrical resistivity of the treated fabric increased sharply with increase in normality from 0.5N to 1.0N for a constant soaking time of 3 h; further increase was marginal at higher normalities (above 1.0N). A sharp increase in the electrical resistivity of the fabric was also found in the initial 1/2 h of soaking when fabrics were soaked in constant normality acid (2N) and resistivity was measured with time. The initial sharp increase in the electrical resistivity was attributed to the bulk removal of Na₂O + K₂O ions which are the main contributors to the conductivity. The removal of bivalent and trivalent ions did not contribute much to the increase in the electrical resistivity at this stage. The electrical resistivity of the treated fabrics increased with increase in the post heat-treatment temperature. During acid treatment, the non-siliceous ions are removed, which makes the fabric porous and susceptible to water absorption. Owing to absorption of moisture, the electrical resistivity of the fabric decreases with time and reaches a constant minimum value. The rate of decrease in electrical resistivity decreases with increase in the normality of the soaking acid. The constant minimum value of electrical resistivity increases with increase in post heat-treatment temperature for a fabric soaked in a constant normality acid. The mechanism of electrical conduction in the acid-treated fabrics after absorption of water is attributed to the proton movement which occurs by the polarization of the diffused water to the interior of the structure.     

Effect of pretreatment on the sublimation of ammonium perchlorate

The effects of pretreatments on the sublimation of pure ammonium perchlorate (AP) were studied by differential thermal analysis. The addition of inorganic salts (doping), or preheating, lead to desensitisation of the sublimation process, whereas it was sensitised by precompression. Sublimation increased with decrease in the particle size of the AP from 500 to 200 microns, but decreased with a further decrease in size from 200 to 100 microns. The results are interpreted in terms of gross imperfections and strain in the AP crystals.     

Effect of heat treatments on the volatile composition of coconut oil

Fresh coconut oil was heated under different conditions for 48 hr at 180 C. The heat treatments included heating in vacuo, heating in air and heating in air and water. The samples were distilled under high vacuum and the volatiles thus obtained were analyzed by combined gas chromatography-mass spectrometry. In all heated samples, a series of n-alkanes and I-alkenes, n-alkanals, methyl alkanones, alkenals, gamma-and delta-lactones, methyl and ethyl esters and free fatty acids were identified. The relative amounts of these compounds varied with the type of heat treatment to which the coconut oil was subjected.     

Atrial fibrillation: new management strategies

The main goal of therapy in atrial fibrillation is to restore sinus rhythm, if this is possible, to avoid adverse hemodynamic, electrical, and embolic consequences. The restoration of sinus rhythm is urgent if the patient is unstable. In a stable patient, if the duration is shorter than 48 hours and an atrial thrombus is unlikely, then sinus rhythm can be restored after initial rate control. If the duration of atrial fibrillation is more than 48 hours, the embolic risk may be significant, and anticoagulation will be required for 2 to 4 weeks before an attempt at cardioversion. In patients in whom sinus rhythm cannot be restored or maintained, the goal of therapy is rate control and reduction of embolic risk unless the risk of anticoagulation outweighs its benefit. In difficult cases, rate control may be accomplished with AV nodal ablation and pacemaker implantation or with one of the surgical procedures described above with varying degrees of normalization of the physiology. Although not included in this flow chart, we do not advocate episodic intermittent therapy for patients with infrequent episodes of atrial fibrillation because this could be potentially dangerous and may place the patient at a higher risk for developing proarrhythmia.