5,621 research outputs found
A NEW METHOD FOR ANALYZING TORQUE CURVES OF UNIAXIAL ANISOTROPIC MATERIALS
No full textWe present a simple analytic method to determine the intrinsic anisotropy energy K(u) and the easy axis orientation delta of a uniaxial anisotropic thin film by analyzing the torque curve. Analytical expressions for K(u) and delta are explicitly derived using the peak value in the measured torque curve and the angle where the torque is zero.We would like to thank A. K. Aganvala for helpful discussions.
This work was supported by Korea Standards Research lnstitute and
the Korea Science and Engineering Foundation under Grant No. 901 -
0206 - 022 - 2
PREDICTIONS OF STRUCTURE WITH SOOT CONCENTRATION OF PROPANE-AIR TURBULENT-DIFFUSION FLAMES
No full textThe required signal power for multimedia traffic in multipath faded CDMA systems
No full textThe reverse link signal power required for multimedia traffic in multipath faded single-code (SC-) and multi-code CDMA (MC-CDMA) systems is investigated. The effect of orthogonality loss among multiple spreading code channels is characterized by introducing the orthogonality factor. The required signal power in both CDMA systems is analyzed with varying system parameters of spreading bandwidth, the orthogonality factor, and the number of spreading codes. Analytical results show that MC-CDMA users transmitting only a single traffic type require significantly more power than SC-CDMA users with only a single traffic type. On the other hand, MC-CDMA users transmitting multimedia traffic require power levels approximately identical to SC-CDMA users with multimedia traffic
Link capacity and signal power according to allocations of spreading codes and bandwidth in CDMA systems
No full textReverse link performance analysis in single-code and multi-code CDMA systems is presented. Results show that the single-code system yields better performance than does the multi-code system in terms of link capacity and signal power. This improvement increases as spreading bandwidth is reduced and the number of spreading codes assigned to a user is increased
Effect of Bandwidth and Spreading Codes on Spectrum Utilization of Spectrally Overlaid CDMA Systems
No full textBuilding bridges between convex regions
No full textAbstractIn the Euclidean traveling salesman and buyers problem (TSBP), we are given a set of convex regions in d-dimensional space, and we wish to find a minimum-cost tour that visits all the regions. The cost of a tour depends on the length of the tour itself and on the distance that buyers within each region need to travel to meet the salesman. We show that constant-factor approximations to the TSBP and several similar problems can be obtained by visiting the centers of the smallest enclosing spheres of the regions
ELECTRICAL AND OPTICAL-PROPERTIES OF DEEP-RED TOP-SURFACE-EMITTING LASERS
No full textBy studying thermal behavior of all-MBE surface-emitting lasers, barrier heights and optimum cavity design parameters are obtained. The barrier heights for holes between hetero-interfaces of Al0.3Ga0.7As-Al0.65Ga0.35As and AlAsAl0.65Ga0.35As (DELTAx = 0.35) are measured to be 77 meV at zero bias for the deep-red top-surface-emitting laser. The barrier height decreases linearly with forward bias voltage, explaining the nonlinearity in current-voltage characteristics of the top-surface-emitting laser. The contribution of electrons to electrical resistance is estimated to be negligibly small compared to that of holes for the structure consisting of DELTAx = 0.35. Minimum threshold current and maximum differential quantum efficiency observed around 200 K indicates slight mismatch between gain maximum and Fabry-Perot resonance for the deep-red top-surface-emitting laser
Doped fibre length and pump power of gain-flattened EDFAs
No full textA simple method for determining the doped fibre length and the pump power of gain-flattened EDFAs has been proposed on the basis of average inversion of the erbium ions with maximum gain flatness. The difference between the obtained and the desired gains to achieve the output power per channel of -5 -5dBm while maintaining the maximum gain flatness was <+/-0.3dB
- …
