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A model for short-term forecasting of electricity demand is developed, which consists of an annual base load augmented by demand variations on a weekly, daily, and hourly or half-hourly basis. Each of these components is individually modelled and forecast, and the aggregate forecast is refined by inclusion of a stochastic component for characterization of variations not attributable to elements of time. The approach is consistent with the operational concept of power system management, and can be readily adopted for on-line forecasting and control. 相似文献
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Y.W. Goh Y.F. Lu Z.M. Ren T.C. Chong 《Applied Physics A: Materials Science & Processing》2003,77(3-4):433-439
Aluminium nitride (AlN) thin films have been grown on Si(100), Si(111) and Sapphire Al2O3(001) substrates by pulsed KrF excimer laser (wavelength 248 nm, duration 30 ns) ablation of an AlN target with the assistance of nitrogen-ion-beam bombardment. The influence of process parameters such as substrate temperature and ion-beam energy has been investigated in order to obtain high-quality AlN films. The AlN films deposited by pulsed-laser deposition (PLD) have been characterized by X-ray diffraction (XRD) to determine the crystalline quality, grain size and growth orientation with respect to the substrate. The XRD spectra of AlN films on Si(100), Si(111) and Sapphire substrates yield full-width-half-maximum (FWHM) values of approximately 1.6. The bonding characteristics in the films have been evaluated by Raman spectroscopy. The chemical composition of the films has been characterized by X-ray photoelectron spectroscopy (XPS). The surface morphology of the films has been measured by atomic force microscopy (AFM). At a substrate temperature of at least 600 °C, polycrystalline AlN films with orientations of AlN(100) and AlN(101) have been synthesized. PACS 68.55.-a; 81.15.Fg; 77.84.Bw 相似文献
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Unprecedented Acid‐Promoted Polymerization and Gelation of Acrylamide: A Serendipitous Discovery 下载免费PDF全文
Siew Yin Chan Dr. Shermin S. Goh Dr. Qingqing Dou Benjamin Qi Yu Chan Dr. Wee Sim Choo Prof. David James Young Prof. Xian Jun Loh 《化学:亚洲杂志》2018,13(14):1797-1804
Dilute acid polymerizes degassed, aqueous acrylamide with concomitant gelation, without the need for added free radical initiator or cross‐linking agent. This reaction is accelerated by sonication or UV irradiation, but inhibited by adventitious oxygen or the addition of a free radical inhibitor, suggesting an acid‐accelerated free radical process. The resulting hydrogels are thixotropic in nature and partially disrupted by the addition of chaotropic agents, indicating the importance of hydrogen bonding to the 3D network. This discovery was made while trying to prepare pectin‐polyacrylamide hydrogels. We observed that pectin initiated the gelation of acrylamide, but only if the aqueous pectin samples had a pH lower than ca. 5. 相似文献
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Boussie TR Diamond GM Goh C Hall KA LaPointe AM Leclerc M Lund C Murphy V Shoemaker JA Tracht U Turner H Zhang J Uno T Rosen RK Stevens JC 《Journal of the American Chemical Society》2003,125(14):4306-4317
For the first time, new catalysts for olefin polymerization have been discovered through the application of fully integrated high-throughput primary and secondary screening techniques supported by rapid polymer characterization methods. Microscale 1-octene primary screening polymerization experiments combining arrays of ligands with reactive metal complexes M(CH(2)Ph)(4) (M = Zr, Hf) and multiple activation conditions represent a new high-throughput technique for discovering novel group (IV) polymerization catalysts. The primary screening methods described here have been validated using a commercially relevant polyolefin catalyst, and implemented rapidly to discover the new amide-ether based hafnium catalyst [eta(2)-(N,O)[bond](2-MeO[bond]C(6)H(4))(2,4,6-Me(3)C(6)H(2))N]Hf(CH(2)Ph)(3) (1), which is capable of polymerizing 1-octene to high conversion. The molecular structure of 1 has been determined by X-ray diffraction. Larger scale secondary screening experiments performed on a focused 96-member amine-ether library demonstrated the versatile high temperature ethylene-1-octene copolymerization capabilities of this catalyst class, and led to significant performance improvements over the initial primary screening discovery. Conventional one gallon batch reactor copolymerizations performed using selected amide-ether hafnium compounds confirmed the performance features of this new catalyst class, serving to fully validate the experimental results from the high-throughput approaches described herein. 相似文献
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Cp2Cr2(CO)4( - 2 - P2), 1, reacts with one molar equivalent of Fe2(CO)9 in THF to yield the mono- and di-iron complexes, Cp2Cr2(CO)4P2[Fe(CO)4], 2, (16.5% yield) and Cp2Cr2(CO)4P2[Fe(CO)4]2, 3, (16.9% yield), as dark magenta brown and dark greenish brown crystals, respectively. Both complexes were characterized by single-crystal X-ray diffraction analysis. Crystal data –2: space group =P21/c,a=17.024(1) Å,b=8.180(1) Å,c=30.891(2) Å, =100.953(5)°,V=4223.4(7)Å3,Z=8, 3743 observed reflections,R
F=0.033; 3: space group P1,a=10.209(2) Å,b=10.212(2) Å,c=15.989(3) Å, =106.93(1)°, =91.87(1)°, =119.50(1)°,V=1356.5(4) Å3,Z=2, 3489 observed reflections,R
F=0.029. 相似文献