A number of facts about quadratic load ow problems y = f(x) = 0, x 2 R n x , y 2 R n y is proved. The main results are the following 1]. If any point x belongs to a straight line connecting a pair of distinct solutions in the state space R n x , the Newton-Raphson iterative process goes along this line. If a loading process y() reaches a singular point of the problem, the corresponding trajecto...

Abstract A Lennard–Jones model of a binary dense liquid (A,B) with a symmetrical miscibility gap is investigated by means of computer simulation methods. Semigrand–canonical Monte Carlo simulations yield the phase diagram in the T–x plane (T : temperature, x: concentration of A or B particles) as well as equilibrated configurations at coexistence. Then Molecular Dynamics simulations use these c...

We assume that internal shocks of gamma-ray bursts (GRBs) consist of multiple sub-jets with a collimation half-angle of about several times gamma-1i, where gammai is the Lorentz factor of each sub-jet. If by chance a sub-jet is first emitted off-axis from the line of sight, the observed peak energy can be in the X-ray region. Next, if by chance a subsequent sub-jet is emitted along the line of ...

We have modelled the X-ray emission from the young rapid rotator AB Doradus (Prot = 0.514 days) using as a basis Zeeman-Doppler maps of the surface magnetic field. This allows us to reconcile the apparently conflicting observations of a high X-ray emission measure and coronal density with a low rotational modulation in X-rays. The technique is to extrapolate the coronal field from the surface m...

Over the last three years, the Galactic center region has been monitored with the Chandra X-Ray Observatory. Besides the X-ray emission from the target object, Sgr A*, diffuse X-ray emission was detected throughout most of the 17 × 17 field of view. With 11 Chandra observations through 2002 June, the total effective exposure reaches ∼590 ks, providing significant photon statistics on much of th...

Let (P,Ξ) be the naturally polarized model of the Prym variety associated to the étale double cover π : C̃ → C of smooth connected curves, where Ξ ⊂ P ⊂ Pic2g−2(C̃), and g(C) = g. If L is any “non exceptional” singularity of Ξ, i.e. a point L on Ξ ⊂ Pic2g−2(C̃) such that h0(C̃, L) ≥ 4, but which cannot be expressed as π∗(M)(B) for any line bundle M on C with h0(C,M) ≥ 2 and effective divisor B ≥ 0 ...

Biological effects of low-dose radiation (LDR) are distinguishable from those of high-dose radiation. Hormetic and adaptive responses are such two examples. However, whether adaptive response could be induced in tumor cells by LDR, especially under in vivo condition, remains elusive, and was systemically investigated in the present study. Four tumor cell lines: two human leukemia cell lines (er...

The fluid flow and heat transfer in a three-dimensional microchannel filled with Al2O3- water nanofluid is numerically investigated. The hybrid scheme is used to discretize the convection terms and SIMPLER algorithm is adopted to couple the velocity and pressure field in the momentum equations. The temperature fields, variation of horizontal velocity along the centre line of the channel, a...