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971.
On the size of small single-walled carbon nanotubes 总被引:1,自引:1,他引:0
We derive a formula relative to the diameter/length ratio of a small single-walled carbon nanotube by means of calculations referring to Fermi energy. These calculations arise from the consideration of the Fermi's velocity for a multiwalled carbon nanotube. 相似文献
972.
973.
INVESTIGATION ON KANE DYNAMIC EQUATIONS BASED ON SCREW THEORY FOR OPEN-CHAIN MANIPULATORS 总被引:4,自引:0,他引:4
IntroductionDynamicsofroboticmanipulatorsisthebasisofdynamiccontrolandmechanicaldesignofroboticmanipulators.Dynamicanalysisofrobotscanemploytheapproachesoftheoreticalmechanicsanddynamicequationsofanalyticalmechanics,suchasNewton_Eulerdynamicequations,Lagrange_Eulerdynamicequations ,Routhequation ,Appellequation ,andKaneequations.Theultimateresultsarethesamewhenweinvestigateononekindofmotionsaboutoneobjectivebydifferentdynamicequations,butthespeedandquantitiesofcomputationoftheseequationsare… 相似文献
974.
A.G. Shmakov O.P. Korobeinichev V.M. Shvartsberg D.A. Knyazkov T.A. Bolshova I.V. Rybitskaya 《Proceedings of the Combustion Institute》2005,30(2):2345-2352
The inhibition/extinction of various flames—premixed stoichiometric C3H8/air, nonpremixed counterflow CH4/O2/N2, and nonpremixed coflow n-heptane/air cup-burner flames doped with a number of phosphorus-containing compounds (PCCs)—has been investigated experimentally. More than 20 PCCs (organic phosphates, phosphonates, phosphates) and their fluorinated derivatives were studied. All PCCs exhibited similar dependencies in burning velocities, extinction strain rates, and extinction volume fractions of CO2 upon PCC loading in the range of mole fractions of 0–7000 ppm within an experimental deviation of ± 5%. This confirms that the inhibition effectiveness of the PCCs is influenced by the phosphorus content in the PCC molecule rather than by the structure of the molecule. The burning velocity of a stoichiometric C3H8/air mixture and the extinction strain rate of a nonpremixed counterflow CH4/O2/N2 flame doped with trimethylphosphate were calculated. Satisfactory agreement between experimental and modeling results confirms the conclusion that the reactions of phosphorus oxyacids with radicals are responsible for flame inhibition. 相似文献
975.
Thin films based on two very different metal-organic systems are developed and some nonlinear optical applications are explored.
A family of zinc complexes which form perfectly polar assemblies in their crystalline state are found to organize as uniaxially
oriented crystallites in vapor deposited thin films on glass substrate. Optical second harmonic generation from these films
is investigated. A simple protocol is developed for thein-situ fabrication of highly monodisperse silver nanoparticles in a polymer film matrix. The methodology can be used to produce
free-standing films. Optical limiting capability of the nanoparticle-embedded polymer film is demonstrated 相似文献
976.
S. H. Saker 《Acta Mathematica Hungarica》2003,100(1-2):37-62
We present new oscillation criteria for the second order nonlinear neutral delay differential equation [y(t)-py(t-τ)]'+ q(t)y
λ
(g(t)) sgn y(g(t)) = 0, t ≧ t
0. Our results solve an open problem posed by James S.W . Wong [24]. The relevance of our results becomes clear due to a carefully
selected example.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
977.
利用铜激光与光纤技术测量光速 总被引:5,自引:2,他引:3
利用脉冲式铜激光技术与光纤技术测量了光速,该实验结合光电技术,提高了测量精度. 相似文献
978.
A topological sphere theorem is obtained from the point of view of submanifold geometry. An important scalar is defined by the mean curvature and the squared norm of the second fundamental form of an oriented complete submanifold Mn in a space form of nonnegative sectional curvature. If the infimum of this scalar is negative, we then prove that the Ricci curvature of Mn has a positive lower bound. Making use of the Lawson–Simons formula for the nonexistence of stable k-currents, we eliminate Hk (Mn, Z) for all 1 ` k ` n – 1.We then observe that the fundamental group of Mn is trivial. It should be emphasized that our result is optimal. 相似文献
979.
硫化天然橡胶物理松弛时间的测量裘怿明刘从伟时锋傅政(青岛化工学院橡胶工程学院青岛266042)关键词硫化天然橡胶,应力松弛速率,数值计算方法,曲线拟合高分子热运动的特点之一是存在松弛现象,通常,人们描述高分子材料的松驰速度采用松驰时间τ[1].实际... 相似文献
980.
本文研究分析了煤岩层的物性参数分布规律和组合特征,阐述了井下物探多参数综合应用的方法原理。通过探测实例论述了井下物探采用多参数综合物探的必要性。指出多参数井下物探可以消除资料的多解性,提高资料解释的准确性。对井下物探工作具有一定的指导意义。 相似文献