The microjet injector system accelerates drugs and delivers them without a needle, which is shown to overcome the weaknesses of existing jet injectors. A significant increase in the delivered dose of drugs is reported with multiple pulses of laser beam at lower laser energy than was previously used in a Nd:YAG system. The new injection scheme uses the beam wavelength best absorbable by water at a longer pulse mode for elongated microjet penetration into a skin target. A 2.9 μm Er:YAG laser at 250 μs pulse duration is used for fluorescent staining of guinea pig skin and for injection controllability study. Hydrodynamic theory confirms the nozzle exit jet velocity obtained by the present microjet system.
We consider a synchronized, circular-orbit binary consisting of a polytrope with index n and a point-mass object, and use a self-consistent field method to construct the equilibrium structure of the polytrope under rotational and tidal perturbations. Our self-consistent field method is distinct from others in that the equilibrium orbital angular velocity is calculated automatically rather than being prescribed, which is crucial for obtaining apsidal motion rates accurately. We find that the centrifugal and tidal forces make perturbed stars more centrally condensed and larger in size. For n = 1.5 polytopes with fixed entropy, the enhancement factor in stellar radii is about 23% and 4 − 8% for µ = 1 and ∼ 0.1 − 0.9, respectively, where µ is the fractional mass of the polytrope relative to the total. The centrifugal force dominates the tidal force in determining the equilibrium structure provided µ > ∼ 0.13 − 0.14 for n > ∼ 1.5. The shape and size of rotationally-and tidally-perturbed polytropes are well described by the corresponding Roche models as long as n > ∼ 2. The apsidal motion rates calculated for circular-orbit binaries under the equilibrium tide condition agree well with the predictions of the classical formula only when the rotational and tidal perturbations are weak. When the perturbations are strong as in critical configurations, the classical theory underestimates the real apsidal motion rates by as much as 50% for n = 1.5 polytropes, although the discrepancy becomes smaller as n increases. For practical uses, we provide fitting formulae for the density concentration, volume radius, coefficient of the mass-radius relation, moment of inertia, spin angular momentum, critical rotation parameter, effective internal structure constant, etc., as functions of µ and the perturbation parameters.
The mass-loss rate of donor stars in cataclysmic variables (CVs) is of paramount importance in the evolution of short-period CVs. Observed donors are oversized in comparison with those of isolated single stars of the same mass, which is thought to be a consequence of the mass loss. Using the empirical mass-radius relation of CVs and the homologous approximation for changes in effective temperature T 2 , orbital period P, and luminosity of the donor with the stellar radius, we find the semi-empirical mass-loss rateṀ 2 of CVs as a function of P. The derivedṀ 2 is at ∼10 −9.5 -10 −10 M yr −1 and weakly depends on P when P > 90 minutes, while it declines very rapidly toward the minimum period when P < 90 minutes, emulating the P-T 2 relation. Due to strong deviation from thermal equilibrium caused by the mass loss, the semi-empiricalṀ 2 is significantly different from and has a less-pronounced turnaround behavior with P than suggested by previous numerical models. The semi-empirical P-Ṁ 2 relation is consistent with the angular momentum loss due to gravitational wave emission and strongly suggests that CV secondaries with 0.075 M < M 2 < 0.2 M are less than 2 Gyr old. When applied to selected eclipsing CVs, our semi-empirical mass-loss rates are in good agreement with the accretion rates derived from the effective temperatures T 1 of white dwarfs, suggesting thatṀ 2 can be used to reliably infer T 2 from T 1 . Based on the semi-empiricalṀ 2 , SDSS 1501 and 1433 systems that were previously identified as post-bounce CVs have yet to reach the minimal period.
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