Development of a Tunable Multiband UWB Radar Sensor and Its Applications to Subsurface Sensing

Development of a new tunable multiband ultra-wideband (UWB) radar sensor is presented. The UWB sensor integrates the transmitter, receiver, and antennas completely in a single package using microwave integrated circuits and operates over multiple pulse durations or frequency bands. The sensor can transmit pulses with duration varying from 450 to 1170 ps and peak power from 200 to 400 mW and can detect signals with a conversion gain of 6.5-9.5 dB and a dynamic range of 50dB over a 5.5-GHz RF bandwidth. It has a range resolution of around 1 in. The sensor performs well through tests of various samples, demonstrating its success for subsurface sensing. The multipulse/multiband feature allows the sensor to achieve both fine-range resolution and long operating range and enhanced target detection and classification     

Increase in urinary calcium and oxalate after fructose infusion

We have previously shown that an oral glucose load increased both calciuria and oxaluria while the ingestion of fructose induced a rise in calciuria and a decrease in oxaluria. This latter effect remains unclear and might be linked to the reduced intestinal oxalate absorption subsequent to digestive intolerance in some subjects. Such a hypothesis could be enlightened by the study of a parenteral fructose load. Therefore in 7 healthy subjects, we compared the effects of fructose infusion (F) (15 min iv infusion at 0.185 mmol/kg BW/min) to a control glucose infusion (G) on urinary calcium and oxalate. In this study, glycemia and insulinemia increased less after (F) than after (G) (respectively + 21% vs + 216%, p < 0.001 and + 230% vs + 402%, p < 0.05) and phosphatemia decreased less after (F) than after (G) (-7% vs -14%, p < 0.05). Urinary calcium and oxalate increased only after (F) (respectively + 64%, p < 0.01 and + 60%, p < 0.05). Urinary uric acid, another urolithiasis factor, increased after both (F) and (G) (respectively + 45%; p < 0.01 and + 42%; p < 0.01) but uricemia increased only after (F) (+ 25%; p < 0.01). Our results suggest an additional reason to avoid the use of fructose in parenteral nutrition, particularly in individuals with a known history of either calcium oxalate or urate urolithiasis.     

Energy-aware wireless networking with directional antennas: the case of session-based broadcasting and multicasting

We consider ad hoc wireless networks that use directional antennas and have limited energy resources. To explore quantitatively the advantage offered by the use of directional antennas over the case of omnidirectional antennas, we consider the case of connection-oriented multicast traffic. Building upon our prior work on multicasting algorithms, we introduce two protocols that exploit the use of directional antennas and evaluate their performance, We observe significant improvement with respect to the omnidirectional case, in terms of both energy efficiency and network lifetime. Additionally, we show that further substantial increase in the network's lifetime can be achieved by incorporating a simple measure of a node's residual energy into the node's cost function.     

A new millimeter-wave step-frequency radar sensor for distancemeasurement

A new compact millimeter-wave distance-measurement sensor prototype has been developed. The sensor is a step-frequency radar implemented using coherent heterodyne technique. It operates in Ka-band (26.5-40 GHz) and is realized using MICs and MMICs. The sensor transmits sinusoidal signals of incremental frequencies and demodulates the received signals into base-band I/Q signals for processing. Experimental results show that the sensor is capable of measuring distance with less than 0.2 inch of absolute error and a low transmitted power of only -20±3 dBm     

A selective CVD tungsten-strapped polysilicon local interconnectiontechnology

A local interconnection technology utilizing polysilicon strapped with selective-chemical-vapor-deposited (CVD) tungsten has been developed. Both n- and p-channel MOS transistors have been successfully fabricated using this technology. Tungsten deposited on polysilicon is an attractive gate shunt and local interconnection material because of its low resistivity, immunity to dopant segregation and diffusion, and resistance to electromigration. A potential problem of this technology is the excessive diode leakage current associated with strapping shallow source/drain diodes with tungsten. The leakage is attributed to defects induced by the heavy source/drain implant, which can be effectively eliminated with a proper annealing procedure     

Benchmarks of simple, generic, shaped plates for validation oflow-frequency electromagnetic computational codes

The validation of low-frequency measurements and electromagnetic (EM) scattering computations for several simple, generic shapes, such as an equilateral-triangular plate, an equilateral-triangular plate with a concentric equilateral-triangular hole, and diamond- and hexagonal-shaped plates, is discussed. The plates were constructed from a thin aluminium sheet with a thickness of 0.08 cm. EM scattering by the planar plates was measured in the experimental test range (ETR) facility of NASA Langley Research Center. The dimensions of the plates were selected such that, over the frequency range of interest, the dimensions were in the range of λ₀ to 3λ₀. In addition, the triangular plate with a triangular hole was selected to study internal-hole resonances     

An analysis of multiple parallel coupled quasi-tem transmission lines

A theoretical analysis of general multiple parallel coupled transmission lines in an inhomogeneous medium is presented. The analysis is based on the generalized telegraphists' equation. It is relatively simple and has the advantage of giving explicit solutions for the properties of the coupled-line system. Considerations are also given to a coupled-line structure whose lines have the same characteristic impedance. Results for two and three coupled lines are found in agreement with those published previously.     

A simple approach to intracytoplasmic sperm injection

OBJECTIVE: To describe a simple injection apparatus and method for performing intracytoplasmic sperm injection in a clinical IVF program. DESIGN: A prospective clinical trial of intracytoplasmic sperm injection. SETTING: A private office-based fertility program. PATIENTS: Five couples undergoing IVF-ET with intracytoplasmic sperm injection as a treatment for male factor infertility. INTERVENTIONS: Intracytoplasmic sperm injection was performed at room temperature (23.5 to 24.5 degrees C) in a simple zwitterion-buffered medium. MAIN OUTCOME MEASURES: Fertilization rates, cleavage rates, clinical pregnancy rates, implantation rates. RESULTS: Intracytoplasmic sperm injection was performed on 44 fresh oocytes from five patients. Twenty-three oocytes fertilized (52.3%) and 22 zygotes cleaved (95.7%). Three of five patients became pregnant (60%), resulting in the live birth of one normal male infant, one continuing singleton pregnancy, and one continuing twin gestation (46XX, 46XY). The implantation rate was 23.5%. CONCLUSION: Intracytoplasmic sperm injection can be performed successfully in a simple medium at room temperature using commercially available microtools.