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991.
992.
Vincenzo Amico Rosa Chillemi Giuseppe Impellizzeri Giovanna Oriente Mario Piattelli Sebastiano Sciuto Corrado Tringali 《The Science of the total environment》1982,24(1):91-99
Levels of PCBs, DDTs and BHCs were measured in sediments taken from the central Mediterranean. BHC was usually < 1 ng g?1; ΣDDT (sum of DDT, DDE and DDD) ranged from < 1 ng g?1 to 27.5 ng g?1; ΣPCBs generally ranged from ca. 1 ng g?1 to > 80 ng g?1, but exceptionally high values (130–457 ng g?1) were observed from stations within Augusta Harbor. 相似文献
993.
A method is presented that offers the possibility of estimating solar irradiation sums on the basis of sunshine and cloudiness observations only. Its application requires the knowledge of the local hourly sums of global and diffuse solar irradiation by clear weather as well as the hourly sums of diffuse solar irradiation due to clouds. These quantities were determined for the actual radiation climate in Lisbon. Effective daily amount of sunshine and cloudiness are defined and compared with the usual daily sunshine and cloudiness concepts; the relationship between daily relative amount of sunshine and cloudiness is established for Lisbon. 相似文献
994.
Diffusion experiments were conducted in vacuum with bimetallic couples of the Ti3Ga (α2) composition and unalloyed α titanium. The gallium-composition profiles after various timetemperature exposures were determined by microprobe analyzer transverses and evaluated by established techniques. Results from this evaluation include the definition of the α to α +α2 and the α + α2 to α2 phase boundaries for the Ti?Ga system and the determination of the interdiffusion coefficients for gallium in the α Ti and Ti3Ga (α2) phases. The interdiffusion coefficients were found to conform to the relationships: $$\tilde D_{\alpha Ti} = 4.4 \times 10^{ - 4} \exp [ - (43.4 \pm 4.7)10^3 /RT]cm^2 /\sec $$ $$\tilde D_{\alpha Ti_3 Ga} = 7.4 \times 10^{ - 5} \exp [ - (43.8 \pm 10.7)10^3 /RT]cm^2 /\sec $$ 相似文献
995.
Y. Deslandes E. Alva Rosa F. Brisse T. Meneghini 《Journal of Materials Science》1991,26(10):2769-2777
We have applied microindentation to a series poly(ether-ether-ketone) films crystallized at different temperatures from the
melt and from the glass to measure their microhardness. The morphology of the samples was characterized by X-ray diffraction,
density measurements and differential scanning calorimetry. The results show that a relationship between microhardness, density
and degree of crystallinity can be established for samples crystallized at various temperatures from both the glass and the
melt. The values of the microhardness of the crystalline component of the samples can be correlated with the lamellar thickness
of the polymer crystals. 相似文献
996.
High-power performance of single-mode fiber-optic connectors 总被引:1,自引:0,他引:1
de Rosa M. Carberry J. Bhagavatula V. Wagner K. Saravanos C. 《Lightwave Technology, Journal of》2002,20(5):879-885
We measured the continuous wave (CW) laser-induced damage threshold of single-mode fiber-optic connectors at 1550 nm. Clean standard physical contact and angled physical contact connectors did not show any evidence of damage for 10 min exposures of 1 W or 3 W. Defective connectors with scratched or undercut endfaces showed identical high-power tolerance as clean connectors without defects. Samples contaminated with carbon black-doped acrylate showed drastic optical failure signatures at approximately 50 mW. Contaminated connectors with expanded mode field diameters ranging from 20 to 62 /spl mu/m showed higher failure thresholds than standard connectors with 10-/spl mu/m spot sizes. We observed that the optical failure threshold power level (P/sub failure/) increased linearly with spot size for the highly contaminated connectors used in this study. 相似文献
997.
The aim of this paper is to construct and apply a model for the allocation of water between two competing users, namely irrigation and hydropower. The model is applied in a case study of a specific water system located in North Eastern Spain. Starting with an irrigation-hydropower joint income function, we develop a constrained maximization process that takes into account the environmental, institutional and actual priority of the water rights. The resulting solution can be useful as a guide for potential bargains between users. Furthermore, we evaluate the results for different supply (precipitation) and water allotments (increase in irrigated land). The results show that there are sufficient incentives so as to reach agreements that lead to improvements in a Pareto sense without side payments. 相似文献
998.
Casimir J. Rosa 《Metallurgical and Materials Transactions A》1983,14(1):199-202
A diffusion coefficient of C in nonstoichiometric α-Mo2C has been determined from the growth kinetics of the carbide layer.
The results conform to the relationship:Dc (in cm2/s) = 68.86 ± 1.51 exp [(-294.77 ± 4.98)/RT] for the temperature range of 1273 to 1673 K, with the activation energy in kJ/mole.
The growth rate,Kp, of the carbide thickness can be expressed as:Kp (in cm2/s) = 32.63 ± 1.52 exp [(-319.06 ± 5.12)/RT]. 相似文献
999.
Rengarajan R. Boyong He Ransom C. Chang Ju Choi Ramachandran R. Haining Yang Butt S. Halle S. Yan W. Lee K. Chudzik M. Robl W. Parks C. Massey J.G. La Rosa G. Yujun Li Radens C. Divakaruni R. Crabbe E. 《Electron Device Letters, IEEE》2002,23(10):621-623
This letter reports on 1.5-V single work-function W/WN/n/sup +/-poly gate CMOS transistors for high-performance stand-alone dynamic random access memory (DRAM) and low-cost low-leakage embedded DRAM applications. At V/sub dd/ Of 1.5-V and 25/spl deg/C, drive currents of 634 /spl mu/A//spl mu/m for 90-nm L/sub gate/ NMOS and 208 /spl mu/A-/spl mu/m for 110-nm L/sub gate/ buried-channel PMOS are achieved at 25 pA//spl mu/m off-state leakage. Device performance of this single work function technology is comparable to published low leakage 1.5-V dual work-function technologies and 25% better than previously reported 1.8-V single work-function technology. Data illustrating hot-carrier immunity of these devices under high electric fields is also presented. Scalability of single work-function CMOS device design for the 90-nm DRAM generation is demonstrated. 相似文献
1000.
Zirconium dioxide (ZrO2) nanoparticles were systematically added as reinforcement to a diglycidyl ether of bisphenol A (DGEBA)-based epoxy resin.
A series of composites with varying amounts of nanoparticles was prepared and their morphology and mechanical properties were
studied. The obtained nanocomposites were characterized by tensile tests, dynamic mechanical thermal analysis, and fracture
toughness (KIC) investigations; by standardized methods, to define the influence of the nanoparticle content on their mechanical and thermal
properties. The morphological analysis of the composites shows that nanoparticles form small clusters, which are uniformly
distributed into the matrix bulk. The tensile modulus (E) and the KIC of the epoxy matrix increase at rising zirconia content. Improvements of more than 37% on modulus and 100% on KIC were reached by the nanocomposite containing 10 vol.-% ZrO2 with respect to the neat epoxy (Eo = 3.1 GPa, KICo = 0.74 MPam0.5). The presence of nanoparticles produces also an increment on glass transition temperature (T
g). The epoxy resin added with 8 vol.-% ZrO2 records a T
g approximately 8% higher than the unmodified matrix (T
go = 100.3 °C). 相似文献