C. Schaeffer

Accessory olfactory bulb lesions and lordosis behavior in the male rat feminized with ovarian hormones

Orchidectomized rats were given estrogen and progesterone and tested for feminine behavior in the presence of a mounting male after accessory olfactory bulb removal (AOBR). Complete AOBR caused a rise in the number of estrogen-progesterone-treated male rats responding by lordosis behavior to male mounts as compared to controls and sham-operated animals. By contrast, LQ scores did not appear to differ in these three groups of animals. The results are discussed in terms of involvement of the main and the accessory olfactory systems in the regulation of feminine behavior in the male rat.

Empirical power MOSFET modeling: practical characterization and simulation implantation

This study deals with power MOSFET models. Parasitic capacitors are one of the main parameters for dynamic models, and have a critical influence on switching waveforms and switching losses. Most of classical models consider that these capacitors are one-voltage dependent. The aim of this paper is to present a new insight based on a physical structure analysis of charge locations and moves and electrical waveforms, both during switching transitions. Establishment of the model with respect to critical voltage changes is presented, and results are compared with experimental curves. This model appears to be more accurate and more reliable than PSPICE or manufacturer original models.

Microchannel integrated heat sinks in silicon technology

The use of microchannels in silicon substrates as a forced liquid cooling device for power integrated circuits is investigated. Thermal dissipation characteristics are calculated for several microchannels geometry. An optimised structure is proposed and its technological realisation is described.

AC switches with integrated gate driver supplies

Monolithic integration dedicated to power electronics applications simplifies design and implementation of converters. This paper presents a simple and highly integrated gate driver powering technique for AC switches and AC to AC converters. Gate driver supply operating principle and integration are first recalled. Then, it is shown how the proposed solution can easily be implemented into or within AC switches made with two elements or even with double sided switches. Finally, it is shown how this gate driver powering technique operates when used in AC to AC converters. An experimental set up comes to validate this operation and the overall approach

Analytical investigation of flat silicon micro heat spreaders

Conventional methods of cooling are not an ideal way to overcome the heat problem in power electronics today. A simple solution would be using micro heat spreader as an integrated part in the silicon substrate. This investigation presents a detailed analysis on maximum heat transfer capabilities of silicon-water cooling devices, flat plate micro heat spreaders. The predictive hydraulic and thermal models were developed to define the heat spreader thermal performances and capillary limitations. Theoretical results of the maximal heat flux that could be transferred agreed reasonably well with the experimental data and the developed model provides a better understanding of the heat transfer capability of micro heat spreaders.

Fuses for power IGBT-converters

The case of a power IGBT can be severely damaged by high fault currents. Fast fuses can eliminate this problem. Studies and tests show that a specially designed fuse can prevent an IGBT from exploding and keep the circuit inductance below acceptable values. A thermal model is proposed in order to see how an IGBT behaves thermally during short circuits and thus to select the appropriate fuses rating.<<ETX>>

Experimental Study of a Pulsating Heat Pipe with Combined Circular and Square Section Channels

Pulsating heat pipes (PHPs) have already found some applications in cooling power / micro electronic components. It was investigated whether a flat plate closed loop pulsating heat pipe can be applied for power electronics cooling. The measured thermal resistances were strongly influenced by the tilt angle, fill rate and working fluid. The best PHP performance was observed with fill rates around 30% in vertical orientation. The maximum heat throughput was 1400 W using water as tested fluid. Methanol results were very close to water performances, even the device was able to work against gravity. Consequently, it was found that the typical PHP concept could be applied with some limitations for power electronics applications with water or methanol as working fluid.

Thermal Management for Stacked 3D Microelectronic Packages

The 3D packaging allow to create compact, lightweight and multifunctional electronic packages. They are obtained by stacking of electronic substrates and ensure better performances of all the system. The main constraint generated by these developments is the thermal management of the entire module. According to applications, specific thermal constraints appear and require the implementation of adapted cooling techniques. The objective of this work is to design and develop a 3D electronic module with the high heat dissipative capacities (50 W). With this intention, a thermal study of the 3D system was led in order to optimize the thermal transfer in the module. Interlayer thermal interactions affect significantly the response of the stacked 3D module. An option of cooling of the module is proposed in order to evacuate the required power. Micro heat pipes were retained to evacuate the required power. The potential applications are envisioned in avionics, space and radar sectors

Electrothermal characterization of IGBT

The improvement of the switch function, due to technological evolution, is still limited by the intrinsic characteristics of silicon. It is therefore crucial, for the design of power convertors, to develop an understanding of electrical and thermal behaviours of power components, in order to estimate their actual performances and to be able to choose a device among several. This experimental and theoretical investigation on IGBTs aims to a better power convertors achievement.<<ETX>>

Lordosis behavior in intact male rats: Effects of hormonal treatment and/or manipulation of the olfactory system

The aim of this study was to investigate the olfactory mechanisms regulating the display of lordosis behavior in intact Wistar male rats bred in our colony. Gonadally intact males show a low capacity to respond by lordosis to male mounts and were insensitive to manipulations of the olfactory system (exposure to the odor of male urine or accessory bulb removal (AOBR)) which have been previously shown to facilitate the display of lordosis behavior in orchidectomized animals primed with ovarian hormones. Treatment with either estradiol benzoate (EB) or EB and progesterone (P) consecutively did not render these gonadally intact animals sensitive to the effects of AOBR. By contrast exposure to male urine was capable of facilitating the display of lordosis behavior in intact male rats given EB + P consecutively. These results are discussed in the light of previous findings showing that (1) two inhibitory structures, the accessory olfactory bulb and the septal and preoptic areas, are involved in the control of lordosis behavior in the male rat; (2) the effects of olfactory cues on the display of lordosis behavior are dependent on the action of both EB and P in orchidectomized animals.