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11.
Joongsuk Park Cam Nguyen 《Microwave and Wireless Components Letters, IEEE》2002,12(6):221-222
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 相似文献
12.
Lee V.V. Kuehne S.C. Nguyen C.T. Beiley M.A. Wong S.S. 《Electron Devices, IEEE Transactions on》1993,40(7):1223-1230
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 相似文献
13.
Cam Nguyen 《Journal of Infrared, Millimeter and Terahertz Waves》1993,14(5):969-985
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. 相似文献
14.
R Fukuda XT Nguyen N Ishimura S Ishihara A Chowdhury N Kohge S Akagi M Watanabe S Fukumoto 《Canadian Metallurgical Quarterly》1995,172(5):1191-1197
Hepatitis B virus (HBV) carriers with antibody to hepatitis e antigen comprise asymptomatic carriers (ASCs), who have low replication levels of HBV, and patients with chronic active hepatitis (CAH), who have high levels of viral replication. To investigate whether defects in the X protein might be responsible for this difference in the level of viral replication, nucleotide sequences of X and precore gene regions in serum HBV were analyzed in 19 ASCs and 9 CAH patients. All patients had a point mutation creating a stop codon in the precore region. Seventeen ASCs (87.3%) had identical mutations consisting of 4 noncontiguous 1-bp deletions or an 8-bp deletion, both of which truncate the normal X protein, whereas no CAH patient had an X gene mutation (P < .001). Thus, deletion of the X protein might be responsible for the low levels of viral replication in ASCs. 相似文献
15.
Development of Online Ultrasound Instructional Module and Comparison to Traditional Teaching Methods
A Web‐based teaching device was constructed to deliver information on fundamentals of ultrasound imaging to approximately one‐half the students in an undergraduate medical imaging course, while the remaining students were taught the same material via traditional lectures and typed notes. The students participating in this study were separated randomly but in such a manner that prior achievement was statistically equivalent for the two groups. After approximately two weeks of instruction, an ultrasound imaging exam was administered. Results indicated no statistically significant difference in scores on homework assigned during the instructional period between the traditional and online groups. Similarly, there was no statistically significant difference in the average exam scores of students in the two groups. The traditional group required significantly more time on learning activities than did the online group. These results indicated that level of understanding was not affected by use of the online device, while efficiency of learning improved dramatically. Reasons reported by the students for the improved efficiency of the online method included flexibility in time usage and ability to cater to the individual, which came with the added responsibility of self‐discipline. The traditional teaching method, meanwhile, allowed interaction with and instant feedback from a professor and other students. In this study we have demonstrated that the nature of an online device yields a higher level of efficiency than traditional lectures, despite the inherent drawbacks of the approach. The effectiveness of this device could potentially be improved by implementing enhancements to increase the level of interaction for the user and to help with discipline and time management. 相似文献
16.
A new miniature bandpass filter, comprising three-conductor short-circuited spurline resonators of approximately a quarter-wavelength long, with a very wide bandwidth approaching multioctaves is reported for the first time. The chain matrix of the filter resonator is derived. The new filter has been developed using microstrip line with less than 1 dB insertion loss over a passband from 2 to 8 GHz. Reasonably good agreement between the measured and calculated results is observed 相似文献
17.
18.
Hayden J.D. Taft R.C. Kenkare P. Mazure C. Gunderson C. Nguyen B.-Y. Woo M. Lage C. Roman B.J. Radhakrishna S. Subrahmanyan R. Sitaram A.R. Pelley P. Lin J.-H. Kemp K. Kirsch H. 《Electron Devices, IEEE Transactions on》1994,41(12):2318-2325
An advanced, high-performance, quadruple well, quadruple polysilicon BiCMOS technology has been developed for fast 16 Mb SRAM's. A split word-line bitcell architecture, using four levels of polysilicon and two self-aligned contacts, achieves a cell area of 8.61 μm2 with conventional I-line lithography and 7.32 μm2 with I-line plus phase-shift or with deep UV lithography. The process features PELOX isolation to provide a 1.0 μm active pitch, MOSFET transistors designed for a 0.80 μm gate poly pitch, a double polysilicon bipolar transistor with aggressively scaled parasitics, and a thin-film polysilicon transistor to enhance bitcell stability. A quadruple-well structure improves soft error rate (SER) and allows simultaneous optimization of MOSFET and bipolar performance 相似文献
19.
Digital filter bank design quadratic-constrained formulation 总被引:5,自引:0,他引:5
Formulate the filter bank design problem as an quadratic-constrained least-squares minimization problem. The solution of the minimization problem converges very quickly since the cost function as well as the constraints are quadratic functions with respect to the unknown parameters. The formulations of the perfect-reconstruction cosine-modulated filter bank, of the near-perfect-reconstruction pseudo-QMF bank, and of the two-channel biorthogonal linear-phase filter bank are derived using the proposed approach. Compared with other design methods, the proposed technique yields PR filter banks with much higher stopband attenuation. The proposed technique can also be extended to design multidimensional filter banks 相似文献
20.