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91.
Bezier surface/surface intersection 总被引:2,自引:0,他引:2
The computational requirements and accuracy of two methods for finding the intersection of Bezier surfaces are examined. In both methods, the existence of an intersection curve is confirmed by using the convex hull property of such surfaces. The first method evaluates the intersection by recursive subdivision of two patches with overlapping hulls. The second method detects a point on the intersection curve and then incrementally traces the intersection in the parametric spaces of the two surfaces. With both methods, the intersection of a pair of first-order planar patches must be solved analytically. The intersection is approximated by first-order Bezier patches in the first case and by planar triangles in the second. Overall, the method of incremental tracing is shown to give more accurate results than the method of recursive subdivision 相似文献
92.
JAIN protocol APIs 总被引:3,自引:0,他引:3
JAIN envisions the creation of a number of Java APIs that abstract the details of networks and protocol implementations, and allow for the development of portable applications. The JAIN Protocol Experts Group (PEG) will focus on developing Java APIs for protocols used in telephony, INs, wireless networks, and the Internet. The PEG is organized into an SS7 subgroup and an IP subgroup. The article provides an introduction to PEG. It next describes the JAIN SS7 APIs. It then describes the JAIN IP APIs. The article also explains how JAIN SS7 and IP APIs can be leveraged for the converged SS7-IP networks of the future and describes the JAIN PEG roadmap 相似文献
93.
N. Recham V.V. Bhat M. Kandavel L. Aymard J.-M. Tarascon A. Rougier 《Journal of Alloys and Compounds》2008,464(1-2):377-382
Enhanced sorption properties of ball-milled MgH2 are reported by adding NbF5. Among various catalyst amounts, 2 mol% of NbF5 reveals to be the optimum concentration leading to significant reduction of the desorption temperature as well as faster kinetics of ball-milled MgH2. At 200 °C, temperature at which MgH2 does not show any activity, MgH2NbF5/2 mol% composite desorbs 3.2 wt.% of H2 in 50 mins. Interestingly, the addition of NbF5 is also associated with an increase in the desorption pressure. At 300 °C, MgH2NbF5/2 mol% composite starts to desorb hydrogen at 600 mbar in comparison with 1 mbar for MgH2. Further improvements were successfully achieved by pre-grinding NbF5 prior to ball-milling the catalyst with MgH2. Such pre-ground NbF5 catalyzed MgH2 composite desorbs 3 wt.% of H2 at 150 °C. Improved properties are associated with smaller activation energies down to values close to the enthalpy of formation of MgH2. Finally, the mechanism at the origin of the enhancement is discussed in terms of catalyst stability, MgF2 formation and electronic density localization. 相似文献
94.
The substrate temperature achieved during physical vapor deposition significantly affects the properties and phases of thin films. An Isoflux ICM-10 Dual Target Inverted Cylindrical Magnetron Sputtering system is used to deposit low temperature alpha-phase alumina, for which an experimentally determined substrate temperature is desired. Constraints inherent to the Isoflux system limit the use of a thermocouple. Instead, a pressure vessel containing numerous samples of temperature indicating liquids is placed in the chamber during operation. These indicator paints are observed upon completion of the deposition process to record the substrate temperature. Measurements indicate a temperature range of 343 °C to 399 °C for our alpha-phase alumina films deposited at a pressure of 0.27 Pa (2 mTorr), a substrate bias of − 35 V, and a power of 5 kW. Theoretical heat transfer calculations support the experimental measurements. A parametric investigation showed that the removal of the − 35 V substrate bias decreases the substrate temperatures by approximately 35 °C and that the substrate temperature increases about 50 °C for each additional kilowatt of power in the range of 1 kW to 6 kW. 相似文献
95.
Sue‐Siang Teh Rajeev Bhat Rosma Ahmad Wan‐Nadiah Wan‐Abdullah Min‐Tze Liong 《International Journal of Food Science & Technology》2010,45(10):2089-2095
We aimed at evaluating agricultural wastes as solid supports for the immobilisation of lactobacilli in a liquid media, namely soymilk. Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733 and L. bulgaricus FTCC 0411 were immobilised on solid supports produced from durian (Durio zibethinus), cempedak (Artocarpus champeden) and mangosteen (Garcinia mangostana). The immobilised cells were inoculated into soymilk and stored at 4 °C over 168 h. Soymilk inoculated with non‐immobilised cells was used as the control. Immobilised cells showed higher survivability over 168 h compared to the control, accompanied by higher reduction of simple sugars and oligosaccharides in soymilk. Higher growth and higher utilisation of substrates also led to the higher production of lactic and acetic acids, which lowered the pH in soymilk compared to the control. Our results illustrated that agrowastes could be used as immobilisers to enhance the growth of lactobacilli in a liquid medium. 相似文献
96.
Favourable conditions for the growth of good quality silicon carbide (SiC) whiskers from rice husk have been discussed in
the light of available evidence on the probable growth mechanism and the theoretical understanding of the same. Preliminary
results indicate an increase in whisker yield at lower temperatures and coarsening of whiskers with longer duration of conversion. 相似文献
97.
We demonstrate the first integration of active electronic devices with semiconductor waveguide modulators. By combining ion-implanted GaAs MESFET amplifiers with directional-coupler electro-optic modulators, the DC drive voltage has been reduced by a factor of ?v = 9, making an effective electro-optic figure-of-merit ?vn3r41 for GaAs superior to that of LiNbO3 相似文献
98.
W.K. Chan J.H. Abeles K.C. Nguyen R. Bhat M.A. Koza 《Photonics Technology Letters, IEEE》1989,1(3):65-67
Optical taps are key elements for optical signal processing. The authors demonstrate the high-speed operation of an InGaAs p-i-n photodetector on InP waveguides. For a 300- mu m-long tap that samples 19% of the light propagating in a 7- mu m-wide waveguide, the response time is 50 ps at a 1 V reverse bias. The taps require a simple epitaxial growth and can readily be integrated with electrooptic modulators and other optoelectronic devices for multigigahertz optical signal processing.<> 相似文献
99.
We report morphology and mechanical properties of natural nanoclay incorporated spunbond polypropylene composite webs. Nanocomposite spunbond webs were produced with up to 5 wt % natural nanoclay additives on Reicofil®‐2 spunbond line. Influence of nanoclay on the resin rheological properties, processibility, and mechanical properties of webs were studied. Wide angle X‐ray diffraction and transmission electron microscopy analysis were used to investigate the nanocomposite morphology. Intercalated and flocculated morphology was observed for all the concentrates and for all the spunbond fiber webs. The microstructure and polymer morphology in the presence of additives was characterized using a polarized optical microscope. At higher percentage, excess clay platelets were excluded out of the spherulite boundaries. About 20–30% increase in tear strength was observed for webs with up to 2 wt % nanoclay additives. Compared with the control polypropylene spunbond web, nanoclay reinforced samples showed better dimensional stability. Different failure mode was observed for spunbond webs with additives. Spunbond webs with even as low as 1 wt % clay retain their morphology and integrity in bond point after thermal bonding. Nanoclay incorporated spunbond webs showed significant improvements in the stiffness. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
100.
Ya.I. Alivov Q. Fan X. Ni S. Chevtchenko I.B. Bhat H. Morko 《Microelectronics Reliability》2010,50(12):2090-2092
Heterojunction bipolar transistor (HBTs) based on Al0.15Ga0.85 N/6H–SiC heterojunction was fabricated. Room-temperature current–voltage (I–V) characteristics of n-Al0.15Ga0.85 N/p-6H–SiC emitter–base heterojunction exhibited good rectifying behavior with a forward current 5 × 10−2 A and reverse current 3 × 10−9 A at 10 V and −10 V, respectively. Analysis of the temperature dependent I–V characteristics of this heterojunction revealed a barrier height of 1.1 eV. The fabricated n-Al0.15Ga0.85 N/p-SiC/n-SiC bipolar transistor did not exhibit common-emitter operation, however, common-base operation was observed with current gain β = IC/IB ranging in 75–100. 相似文献