Search results for "DISPERSION"
showing 10 items of 1101 documents
Polymer Synthesis in Supercritical Carbon Dioxide
2003
It is current opinion of most of the people involved in supercritical fluids (SCFs) technology that as the end of the twentieth century has been devoted to enlarge exploitation of compressed gases in separation processes the beginning of the twenty-first will be mainly aimed to improve their utilisation as solvents for reactions.
Synthesis of Liquid-Crystalline Colloids in Nonpolar Media and their Manipulation in Electric Fields
2009
The first synthesis of anisotropic liquid-crystalline colloids in silicone oil by a direct (radical) polymerization of a monomer in THF/silicone oil mixtures with the help of siloxane containing stabilizers is described. The size of the colloids is in the lower μm range and can be adjusted by varying the mixture. The resulting colloids show a bipolar director configuration if they are small (<1.5 μm) and a radial configuration if they are larger. The colloids are sterically stabilized, and, due to the nonpolarity of the solvent, the disturbing effects of migrating ions are excluded and experiments in the electric field can be conducted. Both line formation in DC fields and a periodic switch…
The Hamilton–Jacobi Equation
2001
We already know that canonical transformations are useful for solving mechanical problems. We now want to look for a canonical transformation that transforms the 2N coordinates (q i , p i ) to 2N constant values (Q i , P i ), e.g., to the 2N initial values \((q_{i}^{0},p_{i}^{0})\) at time t = 0. Then the problem would be solved, q = q(q0, p0, t), p = p(q0, p0, t).
Tunable dual-wavelength thulium-doped fiber laser in the range from 2067 to 2073.5 nm
2017
A tunable dual-wavelength lineal cavity Tm-doped fiber laser is presented. The generation of the laser lines is based on the use of cascaded fiber Bragg gratings and a Hi-Bi fiber optic loop mirror.
Generation of Bound States of Three Ultrashort Pulses With a Passively Mode-Locked High-Power Yb-Doped Double-Clad Fiber Laser
2004
We report the generation of high-power ultrashort bound states of three pulses in an ytterbium-doped double-clad fiber laser. The laser is mode-locked through nonlinear polarization rotation technique in a unidirectional cavity configuration. A pair of diffraction grating is incorporated in the cavity to compensate for the normal dispersion of the fiber. The laser generates chirped bound states of three pulses with either equal or different time separations, with more than 500-pJ energy per pulse. These pulses are subsequently compressed to 100 fs with a compression factor of more than 40.
Actively Q-switched DFB fiber laser for Brillouin sensor applications
2009
Q-switching of distributed feedback (DFB) fiber lasers permits to achieve high peak powers, preserving an ultra narrow linewidth [1,2]. The development of a new in-line acousto-optic modulator based on a magnetostrictive actuator, instead of a piezoelectric-based device, permits an efficient excitation of elastic pulses propagating along the optical fiber and an easy access to both emission outputs of the laser. The repetition rate can be continuously adjusted, as well as the amplitude of the elastic pulses. The interaction of these elastic pulses with a fiber Bragg grating written in an erbium-doped fiber permits an actively Q-switched operation of the DFB fiber laser [3]. The birefringenc…
Single- to three-wavelength switchable ytterbium-doped fiber laser based on intracavity induced loss by a long-period holey fiber grating
2011
In this paper, we propose and demonstrate a versatile and simple single-, dual- and three-wavelength switchable ytterbium-doped fiber laser using the intracavity induced-loss generated by a mechanically induced long-period grating (MLPFG) in a holey fiber. The laser net gain in the cavity is reshaped through the MLPFG by adjusting the twist rate and the pressure of the holey fiber in the long-period grating. In this way, the twist response of the MLPFG enables the laser to switch between the single-, dual-, and three-wavelength operations and the tuning of the simultaneous two- and three-wavelengths. These results are of great interest in the design of flexible multiwavelength sources with …
Impact of diffusion and dispersion of contaminants in water distribution networks modelling and monitoring
2019
Abstract In recent years, there has been a need to seek adequate preventive measures to deal with contamination in water distribution networks that may be related to the accidental contamination and the deliberate injection of toxic agents. Therefore, it is very important to create a sensor system that detects contamination events in real time, maintains the reliability and efficiency of measurements, and limits the cost of the instrumentation. To this aim, two problems have to be faced: practical difficulties connected to the experimental verification of the optimal sensor configuration efficiency on real operating systems and challenges related to the reliability of the network modelling …
3D-Printed Solid Dispersion Drug Products.
2019
With the well-known advantages of additive manufacturing methods such as three-dimensional (3D) printing in drug delivery, it is disappointing that only one product has been successful in achieving regulatory approval in the past few years. Further research and development is required in this area to introduce more 3D printed products into the market. Our study investigates the potential of fixed dose combination solid dispersion drug products generated via 3D printing. Two model drugs&mdash
Convergence in the OECD: Transitional Dynamics or Narrowing Steady-State Differences?
2004
I. INTRODUCTION Research on growth and convergence has proceeded through several stages that can be described as a process of accommodating cross-country heterogeneity into the convergence equation. In the first stage, the world could be described as countries approaching to equal (absolute convergence) or to different (conditional convergence) steady states. In both cases--see Baumol (1986) Barro and Sala i Martin (1992), or Mankiw et al. (1992)--the assumption of parameter homogeneity of the underlying production function was assumed and not tested. Later, some researchers (Knight et al. [1993], Islam [1995], Durlauf and Johnson [1995], or Caselli et al. [1996], among others) began to cha…