Gold thin films, of thickness 30, 60, 100, and 300 angstrom were studied for use as miniature strain gauges. The thin metal films were thermally evaporated onto silicon dioxide coated silicon wafers and patterned into...
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Gold thin films, of thickness 30, 60, 100, and 300 angstrom were studied for use as miniature strain gauges. The thin metal films were thermally evaporated onto silicon dioxide coated silicon wafers and patterned into strain gauges with dimensions of 100 mum x 70 mum and annealed at a maximum temperature of 400-degrees-C. The silicon substrate was cut into cantilever beams to calibrate the strain gauges by loading the beams. The impedance, Z, was measured over a frequency range from 5 kHz to 1 MHz. For the 30, 60, and 100 A thick films the magnitude of the impedance was typically 1 MOMEGA at 5 kHz and the gauge factor ([DELTA\Z\/\Z\]/epsilon) was 24-48 at small strain (epsilon < 2.8 X 10(-6)). The gauge factor was independent of frequency but decreased at larger strains. The 300 angstrom thick films were typically 110OMEGA with a gauge factor of 2.6. The conduction process for the island-like film was modeled with activated tunneling. The sensitivity [DELTA\Z\/\Z\]/epsilon versus strain response model included a contribution from the strain energy in the activated tunneling.
In order to solve the speed problem and shallow reasoning problem met in current research in fault diagnosis expert system, this paper presents a model based parallel fault diagnosis expert system for energy managemen...
The etch rates and plane selectivity for single-crystal silicon anisotropic etching in aqueous rubidium hydroxide are reported. Silicon wafers of (100) and (110) orientation were etched in 25, 30, 40, and 50 weight pe...
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The etch rates and plane selectivity for single-crystal silicon anisotropic etching in aqueous rubidium hydroxide are reported. Silicon wafers of (100) and (110) orientation were etched in 25, 30, 40, and 50 weight percent (w/o) aqueous RbOH at 50, 60, 70, and 80-degrees-C. The activation energy, based on an Arrhenius equation, was 0.48 eV for the (100) and (110) planes. The etch rate ratio for the (110)/(100) planes was equal to 1.5 at 50 w/o, and 0.6 at 25 w/o. The plane selectivity is not a function of temperature. Silicon spheres, approximately 0.25 in. diam were etched to reveal fast etching high index {522}/{311} planes in the vicinity of the [100] direction.
Magnetic resonance imaging and spectroscopy techniques are now being used to detect changes in blood flow, volume and oxygenation level associated with brain function. The authors describe a prototype system, called a...
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An alternative approach, based on a multiple scale analysis, is presented in order to reconcile the traditional WKB approach to the modeling of interplanetary fluctuations in a mildly inhomogeneous large-scale flow wi...
An alternative approach, based on a multiple scale analysis, is presented in order to reconcile the traditional WKB approach to the modeling of interplanetary fluctuations in a mildly inhomogeneous large-scale flow with a more recently developed transport theory. This enables us to compare directly, at a formal level, the inherent structure of the two models. In the case of noninteracting, incompressible (Alfven) waves, the principle difference between the two models is the presence of leading-order couplings (called ''mixing effects'') in the non-WKB turbulence model which are absent in a WKB development. Within the context of linearized MHD, two cases have been identified for which the leading order non-WKB ''mixing term'' does not vanish at zero wavelength. For these cases the WKB expansion is divergent, whereas the multiple-scale theory is well behaved. We have thus established that the WKB results are contained within the multiple-scale theory, but leading order mixing effects, which are Likely to have important observational consequences, can never be recovered in the WKB style expansion. Properties of the higher-order terms in each expansion are also discussed, leading to the conclusion that the non-WKB hierarchy may be applicable even when the scale separation parameter is not small.
A technique for precisely aligning structures before a Au-Si eutectic bond has been developed. A (100) silicon wafer is anisotropically etched to create v grooves around the periphery of the structure to be bonded. Go...
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We present a fast loop parallelization heuristic that assigns separate invocations of a loop to different processors. If the loop contains data dependences between iterations, later iterations can be delayed while awa...
We present a fast loop parallelization heuristic that assigns separate invocations of a loop to different processors. If the loop contains data dependences between iterations, later iterations can be delayed while awaiting a result computed in an earlier iteration. In this paper we study a scheduling problem, called the Delay Problem, that approximates the problem of minimizing the delay in the start time of loops with loop-carried dependences. Our major result is a fast (O(n log 2 n)) time algorithm for the case where the precedence constraints are a forest of in-trees or a forest of out-trees. Since most graphs for the Delay Problem that arise in practice are sparse and consist of such a forest with possibly a few additional edges, this is an important case. We prove that the Delay Problem becomes NP-Complete when the precedence constraints are a set of arbitrary trees. We also prove that the Delay Problem becomes NP-Complete for independent chains when it is generalized to allow either non-unit execution times or release times and deadlines.
The purpose of this article is to demonstrate a simple technique for magnetron sputter deposition of thin ITO films at room temperature without postdeposition annealing. Using a gas mixture of 0.7% O2 balanced with Ar...
The purpose of this article is to demonstrate a simple technique for magnetron sputter deposition of thin ITO films at room temperature without postdeposition annealing. Using a gas mixture of 0.7% O2 balanced with Ar and 50 W rf power, thin films with resistivity as low as 8.2 X 10(-4) OMEGA cm have been fabricated. The sputter deposited films have optical transmittance of over 80% in the visible range. The absorption edge located in the mid-infrared (4000-400 cm-1) has been observed to shift toward increasing wave number (decreasing wavelength) with increasing resistivity of the thin ITO films. At 0.7% O2 concentration it has been found that the resistivity is insensitive to the total pressure of the sputtering chamber over the range of 1.4-8.0 mTorr.
作者：
BOHM, SELHAKEEM, AKHACHICHA, MDepartment of Electrical and Computer Engineering
Concordia University 1455 De Maisonneuve Blvd. West Montreal H3A 1M8 Canada Was born in Montreal
Canada on 14 September 1966. He received the B. Eng. degree in electrical engineering from Concordia University Montreal Canada in 1989. He is at present completing the M.A.Sc. degree in electrical engineering at Concordia University. (S'75–S'79–M'79–SM'86) received the Ph.D. degree from Southern Methodist University
Dallas TX in 1979. He spent the next two years working as a Visiting Professor in Egypt after which he moved to Ottawa Canada in 1982. He assumed teaching and research positions in Carleton and Manitoba Univerities and later moved to Concordia University Montreal Canada in 1983 where he is now a Professor in the Electrical and Computer Engineering Department. He has published numerous papers in IEEE and international journals in the areas of spread spectrum and networking. He is a well-known expert in these areas and serves as a consultant to many companies. His current research interests include wide-band metropolitan networks switching architectures and performance of on-board multibeam satellites acquisitionless CDMA networks code distribution and orthogonalization of CDMA signals responsive congestion control for ATM-based networks ARQ techniques and investigation of the novel SUGAR CDMA systems in fading channels. Dr. Elhakeem is a Senior Member of the Canadian Electrical Engineering Society and Armed Forces Association. He has chaired numerous technical sessions in IEEE Conferences was the Technical Program Chairman for IEEE Montech 1986 Montreal Canada. Dr. Elhakeem is the key guest editor of theIEEE Journal of Selected Areas in Communicationsfor the May June issues 1993 covering CDMA networks. Advanced Technology & Networks
VISTAR Telecommunications Inc. Ottawa Ontario K1G 3J4 Canada An Associate Director of Advanced Technology & Networks Group
VISTAR Telecommunications Inc. Ottawa Canada. He is also an Adjunct Pr
In this paper, we study the performance of a prioritized on-board baseband switch in conjunction with a multibeam satellite handling integrated services. The services considered for the analysis include voice, video, ...
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In this paper, we study the performance of a prioritized on-board baseband switch in conjunction with a multibeam satellite handling integrated services. The services considered for the analysis include voice, video, file transfer and interactive data. The prioritized switch uses both input and output buffering, switch speed-up as well as a two-phase head-of-line resolution algorithm, in order to reduce the buffer loss while maintaining acceptable user delays. The minimum required buffer capacity and switch speed-up for each service in a prioritized environment are found under uniform traffic conditions. It is shown that under uniform traffic conditions, only minimal buffering and switch speed-up are needed even for the lowest priority users. The performance dependence on the switch size is also substantially reduced with head of line resolution and buffering even in a prioritized environment.
Efficient and cost-effective manufacturing techniques can be aided by built-in microsensors. In order to monitor the curing of polyimide, an important component of multichip modules two types of embedded capacitive se...
Efficient and cost-effective manufacturing techniques can be aided by built-in microsensors. In order to monitor the curing of polyimide, an important component of multichip modules two types of embedded capacitive sensors have been developed. One is composed of parallel plates, the other is formed by interdigitated electrodes. The capacitors fabricated on multiple Ultradel(R) 4212 polyimide layers probe the dielectric constant and thickness of the polyimide. Capacitance and loss factor of the sensors are measured after curing the polyinide over the temperature range 100-350-degrees-C, as a function of frequency from 100 kHz to 1 MHz. The interdigitated capacitance decreases during the curing cycle to a stable value indicating that the cure has taken place. Curing time-temperature measurements indicate that a temperature is critical for complete curing. The dielectric constant is calculated from the measured interdigitated capacitance using Schwartz-Christoffel transformation. The film thickness is determined from the parallel plate capacitance. The interdigitated capacitance increases by 4.5% due to humidity, however, when baked at 350-degrees-C the capacitance returns to its initial value. Interdigitated capacitance changes by 10.8% with extra polyimide coating layers.
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