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1.
A. Z. Dubničková S. Dubnička M. E. Biagini A. Castro 《Czechoslovak Journal of Physics》1991,41(12):1177-1188
The behaviour of the -hyperon electric and magnetic form factors is predicted within the modified three resonance ((783), (1020), (1680)) vector-meson dominance (VMD) model with correct analytic properties and the asymptotic behaviour predestinated by the quark model for baryons. The resonance couplings to are evaluated from the known couplings to nucleons by utilizing theSU(3) symmetry and normalization conditions for Dirac and Pauli form factors. The masses and widths of the considered vector mesons are fixed at the world averaged values. The optimal position of the effective inelastic threshold, common for Dirac and Pauli form factors, is determined from the fit of the only existing Orsay DM2 point on the
cross section att=5·693 GeV2. The mean square charge and magnetic radii of the -hyperon are found to be r
E
2
=0·018 F2 and r
M
2
=–0·027 F2, respectively.The authors are very much indebted to Prof. R. Baldini-Ferroli for calling their attention to the problem of -hyperon e.m. ff 's in connection with the FENICE experiment. 相似文献
2.
3.
Characterization of high heating rate chars of biomass fuels 总被引:1,自引:0,他引:1
Data on biomass chars obtained under conditions similar to those of practical applications (high heating rate and low residence time) are required for co-combustion and gasification plants. A methodological procedure is developed and applied to two biomass fuels (cacao shells and olive cake) for producing high heating rate chars and characterizing their reactivity and morphology after the first steps of devolatilization. Different chars are produced in a drop tube reactor (rapid pyrolysis) by varying the nominal temperature and the residence time. Oxidation in air is performed to compare typical temperatures and kinetic parameters and evaluate the effect of the operating conditions on char reactivity. A detailed SEM analysis allows to assess the structural variations during the pyrolysis and detect the main phenomena (softening, swelling, melting, formation of bubbles). A quantitative morphological study is also performed to provide size and shape (important for biomasses) distributions of the parent fuel and the chars. These data are more significant than average values in advanced model to correctly simulate the fluid dynamic behaviour of each dimensional class of particles in large scale furnaces and gasifiers and predict a more reliable residence time of the particles. 相似文献
4.
Quadratic Hedging Methods for Defaultable Claims 总被引:2,自引:0,他引:2
We apply the local risk-minimization approach to defaultable claims and we compare it with intensity-based evaluation formulas
and the mean-variance hedging. We solve analytically the problem of finding respectively the hedging strategy and the associated
portfolio for the three methods in the case of a default put option with random recovery at maturity. 相似文献
5.
Self-injection length in La0.7Ca0.3MnO3-YBa2Cu3O7-δ ferromagnet-superconductor multilayer thin films
We have carried out extensive studies on the self-injection problem in barrierless heterojunctions between La0.7Ca0.3MnO3 (LCMO) and YBa2Cu3O7-δ (YBCO) thin films. The heterojunctions were formed in situ by sequentially growing LCMO and YBCO films on 〈100〉 LaAlO3 (LAO) substrate using a pulsed laser deposition (PLD) system. YBCO micro-bridges with 64 μm width were patterned both on
the LAO (control) and LCMO side of the substrate. Critical current, I
c, was measured at 77 K on both the control side as well as the LCMO side for different YBCO film thickness. It was observed
that while the control side showed a J
c of ∼ 2 × 106 A/cm2, the LCMO side showed about half the value for the same thickness (1800 ?). The difference in J
c indicates that a certain thickness of YBCO has become ‘effectively’ normal due to self-injection. From the measurement of
J
c at two different thicknesses (1800 ? and 1500 ?) of YBCO films both on the LAO as well as the LCMO side, the value of self-injection
length (at 77 K) was estimated to be ∼ 900 ?. To the authors’ best knowledge, this is the first time that self-injection length
has been quantified. A control experiment carried out with LaNiO3 deposited by PLD on YBCO did not show any evidence of self-injection. 相似文献
6.
Smith GE Sladen HL Biagini SC Blower PJ 《Dalton transactions (Cambridge, England : 2003)》2011,40(23):6196-6205
Conventional methods for radiolabelling biomolecules such as proteins and peptides with fluorine-18 for PET imaging rely on carbon-fluorine bond formation and are complex and inefficient. Several non-carbon elements form strong bonds (i.e. with high bond enthalpy) with fluorine, but with lower activation energy for their formation compared to carbon-fluorine bonds, whilst preserving a relatively high kinetic stability. In particular, by incorporating boron-, aluminium- and silicon-containing prosthetic groups into biomolecules, promising results have recently been achieved in the radiolabelling with F-18-fluoride under mild aqueous conditions, affording a level of convenience, efficiency and specific activity potentially superior to those offered by conventional C-F bond formation methods. The promise already shown by these early studies heralds a new branch of bioconjugate radiochemistry involving a wider range of "fluoridephilic" elements for synthesis of PET molecular imaging agents. 相似文献
7.
8.
The purpose of this paper is to present a general stochastic calculus
approach to insider trading. We consider a market driven by a standard Brownian
motion $B(t)$ on a filtered probability space $\displaystyle
(\Omega,\F,\left\{\F\right\}_{t\geq 0},P)$ where the coefficients are
adapted to a filtration ${\Bbb G}=\left\{\G_t\right\}_{0\leq t\leq T}$,
with $\F_t\subset\G_t$ for all $t\in [0,T]$, $T>0$ being a fixed terminal time.
By
an {\it insider} in this market we
mean a person who has access to a filtration (information)
$\displaystyle{\Bbb H}=\left\{\H_t\right\}_{0\leq t\leq T}$ which is strictly
bigger than the filtration
$\displaystyle{\Bbb G}=\left\{\G_t\right\}_{0\leq t\leq T}$.
In this context an insider strategy is represented by an
$\H_t$-adapted process
$\phi(t)$ and we interpret all anticipating integrals as
the forward integral defined in
[23] and [25].
We consider an optimal portfolio problem with
general utility for an insider with access to a general information
$\H_t \supset\G_t$ and show that if
an optimal insider portfolio $\pi^*(t)$ of this problem exists, then
$B(t)$ is an $\H_t$-semimartingale, i.e. the enlargement
of filtration property holds. This is a converse of previously
known results in this field.
Moreover, if $\pi^*$ exists
we obtain an explicit expression in terms of $\pi^*$ for the
semimartingale decomposition of $B(t)$ with respect to $\H_t$.
This is a generalization
of results in [16], [20] and [2]. 相似文献
9.
Francesca Biagini Yaozhong Hu Bernt
ksendal Agns Sulem 《Stochastic Processes and their Applications》2002,100(1-2):233-253
We prove a stochastic maximum principle for controlled processes X(t)=X(u)(t) of the formwhere B(H)(t) is m-dimensional fractional Brownian motion with Hurst parameter
. As an application we solve a problem about minimal variance hedging in an incomplete market driven by fractional Brownian motion. 相似文献
dX(t)=b(t,X(t),u(t)) dt+σ(t,X(t),u(t)) dB(H)(t),
10.