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941.
Gu P Haas P Hogan WP Kim SK Matthews JN Myung SS Schnetzer S Thomson GB Zou Y Arisaka K Roberts D Slater W Spencer MB Weaver M Briere RA Cheu E Harris DA Krolak P McFarland KS Roodman A Schwingenheuer B Somalwar SV Wah YW Winstein B Winston R Barker AR Swallow EC Bock GJ Coleman R Crisler M Enagonio J Ford R Hsiung YB Jensen DA O'Dell VR Ramberg E Tschirhart R Collins EM Gollin GD Nakaya T Yamanaka T 《Physical review letters》1996,76(23):4312-4315
942.
943.
Gerhard Hasslinger Erik S. Rieger 《The Journal of the Operational Research Society》1996,47(5):640-653
This paper deals with approximate analysis methods for open queueing networks. External and internal flows from and to the nodes are characterized by renewal processes with discrete time distributions of their interarrival times. Stationary distributions of the waiting time, the queue size and the interdeparture times are obtained using efficient discrete time algorithms for single server (GI/G/1) and multi-server (GI/D/c) nodes with deterministic service. The network analysis is extended to semi-Markovian representations of each flow among the nodes, which include parameters of the autocorrelation function. 相似文献
944.
Steve PhillipsJr. 《The Journal of the Operational Research Society》1996,47(5):697-701
The paper presents an application oriented procedure for solving the project management duration/resource tradeoff problem. A procedure is presented for reducing a project from a normal to a crash duration state at a minimum amount of additional resource expenditure assuming a linear utilization functions. The procedure is network based using a graphical Cut Search Approach to locate the minimal resource level at each reduction in total project duration. Activity-on-arc networks and flow networks are utilized. The paper is presented for practical application and for conceptual development as compared to a theoretical treatment. 相似文献
945.
946.
Krishna S Kumar 《Pramana》1993,41(1):45-53
We report on two sensitive tests of lepton universality carried out by the 4 LEP experiments at the Z0 pole. From measurements of the τ polarization in e+ e?→τ + τ ?, the ratios of the vector and axial vector coupling constants of the electron and the tau lepton to the weak neutral current are obtained to beg v e /g a e =0.066±0.015 andg V τ /g A τ =0.070±0.009 respectively. From measurement of the τ lifetime and the τ leptonic branching ratios, the ratio of the coupling constants describing weak leptonic decays of the τ and the μ is measured to beG τ /G μ =0.996±0.008. 相似文献
947.
A review is given of the StandardSU(5) supergravity model. This model has passed an important check regarding unification of the electro-weak and the strong couplings using high precision LEP data. It is shown that for a significant domain of the parameter space the model also satisfies constraints on the SUSY spectrum from CDF and LEP, as well as proton stability and cosmological relic density constraints. 相似文献
948.
Hanjiang Dong Zhengping Zhang Man-Ho Lee D. W. Mueller Richard F. Reidy 《Journal of Sol-Gel Science and Technology》2007,41(1):11-17
Sol-gel polymerization of methyltrimethoxysilane (MTMS) in ethanol using a two-step acid/base catalyzed procedure (B2) is
followed by 29Si NMR spectroscopy. Analysis of the structural evolution of the B2 system shows that esterification of monomeric and end
silicon species is rate-limited while that of linear and cyclic species is able to reach pseudoequilibrium in the second basic
step. Condensation reactivity is reduced with increasing network connectivity, however, to a much less degree under B2 conditions
than MTMS polymerization under acidic conditions. Steric effects as well as many other factors are attributed to this trend.
The concentration of cyclic and polycyclic species of the B2 system is nearly 3 times lower compared to the acid-catalyzed
system. The empirical degree of condensation at the gel point is determined to be 0.88. The effects of cyclization and phase
separation on MTMS gelation are discussed for both B2 and acid-catalyzed systems. Based on these results it is believed that
MTMS-based gels form for B2 and not acid-catalyzed conditions due to reduced cyclization, rapid hydrolysis and condensation,
effective use of functional groups, and effective contribution of branched and polycyclic species as crosslinking points to
connect polymeric chains in the B2 system. 相似文献
949.
Two flow injection analyses (FIA) methods for the determination of diffusion coefficients in a straight single tube FIA system were developed. Based on the analytical solution of the convection-diffusion equation, linear relationships of the logarithmic values of the dispersion coefficient (D) and the half-peak width (W1/2) with the diffusion coefficient (Dm) were obtained. Experiments were designed to verify these methods. For example, for potassium hexacyanoferrate (III) a Dm value of 0.72 × 105 cm2 s−1 was found versus a literature value of 0.76 × 105 cm2 s−1 (error, 5%). For potassium hexacyanoferrate (II) a Dm value of 0.67 × 105 cm2 s−1 was obtained versus a literature value of 0.63 × 105 cm2 s−1 (error, 6%). The diffusion coefficients of some important biomedical compounds, such as dopamine, epinephrine, norepinephrine and ascorbic acid, were then determined. The values of 105 Dm/cm2 s−1 are 0.60 ± 0.03, 0.44 ± 0.02, 0.60 ± 0.01 and 0.68 ± 0.06, respectively. 相似文献
950.
The extended Koopmans’ theorem is related to Fukui function, which measures the change in electron density that accompanies
electron attachment and removal. Two approaches are used, one based on the extended Koopmans’ theorem differential equation
and the other based directly on the expression of the ionized wave function from the extended Koopmans’ theorem. It is observed
that the Fukui function for electron removal can be modeled as the square of the first Dyson orbital, plus corrections. The
possibility of useful generalizations to the extended Koopmans’ theorem is considered; some of these extensions give approximations,
or even exact expressions, for the Fukui function for electron attachment. 相似文献