Single chamber compact two-phase heat spreaders withmicrofabricated boiling enhancement structures

Presents the thermal performance evaluation of a compact single-chamber two-phase heat spreader. The heat spreader setup has a central evaporator section with integrated fins for cooling along the edges. The evaporator employs a micro-fabricated three-dimensional (3-D) copper structure for enhancing boiling heat transfer. The thermal performance of the system was characterized at various power levels and condenser cooling conditions. The size of the boiling enhancement structure and effects of liquid fill volumes on performance were also investigated. Incorporation of the enhancement structure resulted in an improvement in the spreader thermal performance by decreasing the wall temperature at the evaporator by 8°C, for a power dissipation of 36 W/cm² at an air speed of 1 m/s. The maximum heat flux obtained based on a maximum evaporator temperature of 75°C for an air speed of 1 m/s was 42.5 W/cm². Variation in the liquid fill volume showed negligible effect on the maximum temperature at the evaporator, as long as the enhanced structure was fully flooded     

A method of simulating magnetically driven arcs [in switchgear]

This paper presents a new, practical method of simulating the behavior of arcs driven by magnetic forces in a gas. This simulation method is very useful in designing electric devices using magnetically driven arc techniques. First, the authors describe the arc model. In this model, the arc is assumed to be a chain of small rigid cylindrical current elements. Each element receives Lorentz's force from the magnetic field and a fluid drag force from the surrounding gas. Owing to the similarity between an arc and a rigid column, the drag force of the arc is expressed by that of the column. The element moves with the velocity determined by these forces. Consequently, one can obtain the behavior and the shape of the whole arc. Finally, a simulation example is shown     

Interfacial lithium-ion transfer at the LiMn2O4 thin film electrode/aqueous solution interface

Interfacial lithium-ion transfer at the LiMn₂O₄ thin film electrode/aqueous solution was investigated. The cyclic voltammograms of the film electrode conducted in the aqueous solution was similar to an adsorption-type voltammogram of reversible system, suggesting that fast charge transfer reaction proceed in the aqueous solution system. We found that the activation energy for this interfacial lithium-ion transfer reaction obtains 23–25 kJ mol⁻¹, which is much smaller than that in the propylene carbonate solution (50 kJ mol⁻¹). This small activation energy will be responsible for the fast interfacial lithium-ion transfer reaction in the aqueous solution. These results suggest that fast lithium insertion/extraction reaction can be realized by decreasing the activation energy for interfacial lithium-ion transfer reaction.     

Images in cardiovascular medicine. Primary cardiac B-cell lymphoma

This article describes a procedure for making an interocclusal record for a remount procedure after tryin of the castings. This method can also be used for the initial mounting by substituting autopolymerizing acrylic resin copings for the metal castings.     

Impurity-profile-based threshold-voltage model of pocket-implanted MOSFETs for circuit simulation

A new threshold voltage (V/sub th/) model has been developed for the pocket-implant technology. The model extracts the threshold condition from the entire mobile charge concentration in the channel with only five additional parameters; the maximum doping concentration (N/sub subp/) of the pocket profile, the penetration length (L/sub p/) into the channel, and three enhanced short-channel parameters. The model reproduces the measured V/sub th/ versus. gate-length (L/sub gate/) characteristics with an average error of a few millivolts under any bias conditions.     

Enhanced protein synthesis in the ipsilateral substantia nigra following middle cerebral artery occlusion in the rat

The purpose of this randomised single blinded study was to determine the optimal size of laryngeal mask airway in the normal adult population, to test the validity of the current selection criteria and to determine if any externally measured anatomical variable correlated with optimal size. In each of 30 apnoeic anaesthetised adults weighting less than 100 kg, size 3, 4 and 5 laryngeal mask airways were inserted in random order by a skilled user and the cuff inflated to a standard pressure (60 cm H2O). Optimal size was based on four criteria in order of priority: number of attempts at placement, oropharyngeal leak pressure, fiberoptic score and percentage of vocal cords seen. The size 5 laryngeal mask airway was optimal in 19/30 and the size 4 in 11/30. In no patient was the size 3 the optimal fit. Oropharyngeal leak pressure was significantly higher for each progressively large size and the fiberoptic view was significantly better for the size 4 and size 5. There was no significant predictive value in any externally measured anatomical variable, but height was the most useful. The best current selection strategy was to choose a size 5 for males and size 4 for females. Potentially useful new strategies may be to use the size 5 in all adults, or a size 5 > or = 165 cm in height and size 4 for < 165 cm. We conclude that predicting the optimal size of laryngeal mask airway for individual adult patients is complex. The best size selection strategies involve use of the size 4 and 5 laryngeal mask airways in adults.