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801.
Regina Benveniste 《Mathematical Programming》1981,21(1):224-228
A method is presented for the solution of the parametric quadratic programming problem by the use of conjugate directions. It is based on the method for quadratic programming proposed by the author in [1].While engaged in this research the author had a part-time post with the Manpower Services Commission. 相似文献
802.
803.
Rodolfo L. Patyk Bruno S. Lomba Ana Flávia Nogueira Clascídia A. Furtado Adelina Pinheiro Santos Regina M. Q. Mello Liliana Micaroni Ivo A. Hümmelgen 《固体物理学:研究快报》2007,1(1):R43-R45
We report the preparation of photovoltaic devices using modified single wall carbon nanotubes, SWNTs. Devices are produced stacking on top of fluorine‐doped tin‐oxide, an electrochemically deposited polybithiophene layer, a layer of SWNT blended with poly(3‐octylthiophene) and an evaporated top metal contact, Ca/Al or Al. Ca/Al‐top‐electrode devices achieve open‐circuit voltages of 1.81 V and average power conversion efficiency of 1.48% at irradiance of 15.5 W m–2, spectrally distributed following AM1.5. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
804.
Luisa Bataglin Avila Elis Regina Correa Barreto Paloma Krolow de Souza Brbara De Zorzi Silva Thamiris Renata Martiny Caroline Costa Moraes Marcilio Machado Morais Vijaya Raghavan Gabriela Silveira da Rosa 《Molecules (Basel, Switzerland)》2020,25(23)
This research investigated the bioactive potential of jaboticaba peel extract (JPE) and proposed an innovative material for food packaging based on carrageenan films incorporated with JPE. The extract was obtained through microwave assisted extraction (MAE) according to central composite rotational design and the optimized conditions showed a combined antimicrobial and antioxidant actions when the extraction process is accomplished at 80 °C and 1 min. The carrageenan film incorporated with JPE was manageable, homogeneous and the presence of JPE into film increased the thickness and improved the light barrier of the film. The results of solubility and mechanical properties did not show significant differences. The benefit of using MAE to improve the recovery of bioactive compounds was demonstrated and the carrageenan film with JPE showed a great strategy to add additives into food packaging. 相似文献
805.
Reinald Fischer Heiner Schmidt Fadi M. Younis Helmar Görls Regina Suxdorf Matthias Westerhausen 《无机化学与普通化学杂志》2020,646(4):207-214
The reaction of MCl4(thf)2 (M = Zr, Hf) with 1,4-dilitiobutane in diethyl ether at –25 °C or at 0 °C with a molar ratio of 1 : 3 yields the homoleptic “ate” complexes [(thf)4Li] [{(thf)Li}M(C4H8)3] 1 - Zr (M = Zr) and 1 - Hf (M = Hf). The crystalline compounds form ion lattices with solvent-separated [(thf)4Li]+ cations and [{(thf)Li}M(C4H8)3]– anions. The NMR spectra at –20 °C show magnetic equivalence of the M–CH2 and of the β-CH2 groups of the butane-1,4-diide ligands on the NMR time scale. Analogous reactions of MCl4(thf)2 with 1,4-dilithiobutane with a molar ratio of 1 : 2 proceed unclear. However, single crystals of [Li(thf)4] [HfCl5(thf)] ( 2 ) can be isolated with the hafnium atom in a distorted octahedral coordination sphere of five chloro and one thf ligand. NMR spectra allow to elucidate the time-dependent degradation of 1-Hf and 1-Zr in THF and toluene at 25 °C via THF cleavage. Addition of tmeda to a solution of 1-Zr allows the isolation of intermediately formed [{(tmeda)Li}2Zr(nBu)2(C4H8)2] ( 3 ). 相似文献
806.
Crystals of Pd2MCh2 (M=Fe, Co, Ni; Ch=Se, Te) were synthesized by heating the elements at 823-1323 K in silica ampoules under argon atmosphere. Their structures were determined by single-crystal X-ray diffraction at room temperature. The metallic compounds crystallize in a variant of the K2ZnO2 type (Ibam, Z=4, Pd2CoSe2: a=5.993(1), b=10.493(2), c=5.003(1) Å; Pd2FeSe2: a=5.960(1), b=10.576(2), c=5.078(1) Å; Pd2CoTe2: a=6.305(1), b=11.100(2), c=5.234(1) Å; Pd2NiTe2: a=6.286(1), b=11.194(2), c=5.157(1) Å). One-dimensional tetrahedra chains with remarkably short M—M bonds run along [001], separated by [Pd2] dumbbells with palladium in fivefold coordination of selenium or tellurium atoms. The structure may also be described as a filled variant of the SiS2 type. M atoms occupy of the tetrahedral voids and the Pd atoms fill all octahedral voids in a distorted ccp motif of chalcogen atoms. Even though the Pd2MCh2 compounds are isotypic to K2ZnO2 from the crystallographic viewpoint, we find a different bonding situation with additional homo- and heteronuclear metal-metal bonds between the Pd and Co atoms. The electronic structures and topologies of the electron densities of Pd2CoSe2 and isotypic Na2CoSe2 are analyzed and compared by using Bader's AIM theory. Different values of topological charge transfer and electron density flatness indices uncover striking quantitative differences in the nature of chemical bonding between the metallic compound Pd2CoSe2 and nonmetallic Na2CoSe2. 相似文献
807.
Ethanol/water pulps from sugar cane straw and their biobleaching with xylanase from Bacillus pumilus
The influence of independent variables (temperature and time) on the cooking of sugar cane straw with ethanol/water mixtures was studied to determine operating conditions that obtain pulp with high cellulose contents and a low lignin content. An experimental 2(2) design was applied for temperatures of 185 and 215 degrees C, and time of 1 and 2.5 h with the ethanol/water mixture concentration and constant straw-to-solvent ratio. The system was scaled-up at 200 degrees C cooking temperature for 2 h with 50% ethanol-water concentration, and 1:10 (w/v) straw-to-solvent ratio to obtain a pulp with 3.14 cP viscosity, 58.09 kappa-number, and the chemical composition of the pulps were 3.2% pentosan and 31.5% lignin. Xylanase from Bacillus pumilus was then applied at a loading of 5-150 IU/g dry pulp in the sugar cane straw ethanol/water pulp at 50 degrees C for 2 and 20 h. To ethanol/water pulps, the best enzyme dosage was found to be 20 IU/g dry pulp at 20 h, and a high enzyme dosage of 150 IU/g dry pulp did not decrease the kappa-number of the pulp. 相似文献
808.
Alina Khaybullina Gulnaz Akhtaryanova Regina Mingazova Debasish Saha Ramil Izmailov 《International Journal of Theoretical Physics》2014,53(5):1590-1600
We investigate the stability regions of the thin-shells obtained by gluing the exterior Schwarzschild vacuum with two distinct classes of Ellis wormholes, one with zero and the other with nonzero total mass. Using the new concepts of thin-shell “mass” and of “external force” discovered recently by Garcia, Lobo and Visser, we shall apply their method to the explicit cases where some of the energy conditions in the bulk (on two sides) are violated. The stability regions are analyzed and the energetics is briefly discussed. Remarkably, we find that the stability zones are quite similar although the classes of Ellis wormholes are different. By the present examples, we confirm that the stability zones indicated by the force constraint (involving Φ and its derivatives) are more complete but restrictive than those from the mass constraint (not involving Φ). 相似文献
809.
We report a first dissipative dispersive-managed soliton fiber laser operating at 2?μm. The cavity comprised of all-anomalous-dispersion fiber employs chirped fiber Bragg grating, which ensures net-normal cavity dispersion and semiconductor saturable absorber for mode-locking. 相似文献
810.
For a two-class two-node bandwidth sharing network called parking lot network we investigate the tail behavior of the queue
length and sojourn time under light-tailed assumptions. These results extend previous results in the literature obtained for
a single-node network. Explicit conditions are given that indicate whether congestion at the second node influences the large
deviations behavior or not. To overcome the complexities that arise when moving away from the single node case, we rely on
recent results on overloaded bandwidth sharing networks obtained by Borst et al. (2009), and a comparison with the modified
proportional fairness discipline, as introduced by Massoulié (Ann Appl Probab 17: 809–839, 2007). Specifically, our results include upper bounds for the distribution of the number of flows in the network, finiteness of
the moment generating function of the workload, and large-deviations asymptotics for the sojourn time assuming flow size distributions
having a bounded hazard rate. 相似文献