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排序方式: 共有225条查询结果,搜索用时 15 毫秒
51.
M. Martinez Ll. Garrido R. Miquel J. L. Harton R. Tanaka 《Zeitschrift fur Physik C Particles and Fields》1991,49(4):645-655
An improved model independent formula to fit theZ line shape parameters is presented. The accuracy of the QED radiative corrections used in the formula is estimated, as is the absolute accuracy of the formula itself. The precision of the formula is compared with existing fitting formulae, in terms of cross sections produced and in terms of theZ parameters returned from a fit. The errors which the LEP-SLC experiments can expect to achieve on theZ parameters are examined as a function of total integrated luminosity. The formula presented here can fit theZ parameters with high accuracy: below 1 MeV for theZ mass, the order of 1 MeV for total width, and below 0.04% for the hadronic and leptonic peak cross sections. Such biases will remain much below the expected experimental uncertainties from LEP and SLC. 相似文献
52.
R.?VarónEmail author M.?García-Moreno F.?García-Molina M.?E.?Fuentes E.?Arribas J.?M.?Yago M.?Ll.?Amo-Saus E.?Valero 《Journal of mathematical chemistry》2005,38(4):437-450
Taking as starting point a previous contribution about the kinetics of the transient phase and steady-state of monocyclic
enzyme cascades, this paper suggest the definition and use of new regulatory modification properties involving the time elapses
from the onset of the reaction to the attainment of the steady-state for a monocyclic enzyme cascade. A minimal set of simplifying
assumptions allowing to derive analytical expressions for these properties has been used. From these general expressions we
derive, as particular cases, other simpler expressions by using additional assumptions which have, therefore, a smaller range
of validity. A discussion of the relationships between the kinetic parameters and concentrations needed to the additional
assumption is observed is carried out. The goodness of our analysis has been tested by using numerical integration of the
set of differential equation describing the kinetic behaviour of the cascade. The results obtained for a type of cascade are
extrapolable to other different schemes of monocyclic enzyme cascades. Finally, a kinetic data analysis and an experimental
design are suggested 相似文献
53.
在邻苯二甲酸氢钾 HCl 乙醇 水溶液中,钼(Ⅵ) 水杨基荧光酮体系在滴汞电极上,于-1.10V(vs.SCE)处有一良好的极谱波,其二阶导数峰电流与钼(Ⅵ)在8×10-10~6×10-8mol L范围内有良好的线性关系,检出限为5×10-10mol L。研究了极谱波的性质和电极反应机理。该方法已用于水及生物样品的测定。 相似文献
54.
M. Valın-Rodrıguez A. Puente Ll. Serra 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):387-390
We report an analysis of the dipole response of a symmetric quantum-dot molecule as a function of the dot-dot separation and
intensity of a perpendicular magnetic field. The potential barrier is assumed proportional to the interdot distance using
a two-center oscillator potential. The results are obtained within the symmetry-unrestricted TDLSDA. It is shown that the
FIR details, specially the fragmentation of the low-energy brach, are quite sensitive to the interdot separation and that
in both the small and large separation limits the results converge towards the analytic Kohn's magnetoplasmon energies. The
validity of the LSDA is checked by comparison with the Hartree-Fock dipole spectrum in one case.
Received 29 November 2000 相似文献
55.
Dan Shan Shao-lin Mu Bing-wei Mao Yong-fang Li Department of Chemistry School of Science Yangzhou University Yangzhou China State Key Laboratory of Physical Chemistry of Solid Surface Xiamen University Xiamen China Center for Molecular Science. Institute of Chemistry Chinese Academy of Sciences Beijing China 《高分子科学》2001,(5):483-492
The electrochemical copolymerization of aniline and N,N,N'-trimethylthionin (azure B) in aqueous solutions hasbeen carried out using the potential sweep method, The optimum conditions for the coelectrodeposition are that the pH valueand the temperature of the electrolytic solution are controlled at 5.57 and 30℃, respectively, and the scan potential range isset between - 0.25 and 1.10 V (versus SCE). The copolymerization rate of aniline and azure B is about 3 times larger thanthat of aniline in the absence of azure B. The copolymerization of aniline and azure B was verified from the results of visiblespectra during electrolysis, FTIR spectra and the atomic force microscopy (AFM) images of the polymers. The in situ visiblespectrum for the electrolysis of the solution containing aniline and azure B is different from that of the respective aniline andazure B. The FTIR spectrum of the copolymer is not a superposition of that of polyaniline and poly(azure B). The AFMimage of the copolymer is different from those of polyaniline and poly(azure B) and is not a mixture of individual polymers.The conductivity of thc copolymer synthesized at pH 5.57 is four orders of magnitude higher than that of polyanilinesynthesized under the same conditions, bat in the absence of azure B. The clectrochemical properties of the copolymer aremainly attributed to polyaniline, but the copolymer has a better electrochemical reversibility and a much faster charge transferthan those of polyaniline. 相似文献
56.
给出了相距为d的两个单电子圆盘量子点构成的人造分子的能级结构,讨论了能级随d,ω0(谐振子圆频率)及B(外磁场强度)变化的情况。 相似文献
57.
采用溶胶-凝胶法制备了单轴M型锶铁氧体SrFe12-x12-xCrxxO 1919(x=0—1)超细晶粒.实验结果表明, 随掺杂量x的增大,质量饱和磁化强 度σss在x≤04范围内增大,在x=02附近达到极大值.矫顽力Hcc在x<05的范围 内单调降低,这对于用作高密度磁记录材料非常有利.当x≤04时,样品是单相结构, 在 x=06以后出现非磁性相α-Fe22O3<
关键词:
锶铁氧体
3+')" href="#">Cr3+3+
结构
磁性 相似文献
58.
An analytical solution to the famous Falkner-Skan equation for the magnetohydrodynamic (MHD) flow is obtained for a special case, namely, the sink flow with a velocity power index of -1. The solution is given in a closed form. Multiple solution branches are obtained. The effects of the magnetic parameter and the wall stretching parameter are analyzed. Interesting velocity profiles are observed with reversal flow regions even for a stationary wall. These solutions provide a rare case of the Falkner-Skan MHD ... 相似文献
59.
60.