Search results for " solution"

Multiple solutions for a Sturm-Liouville problem with mixed boundary conditions

2010

Investigating the cryopreservation of nodal explants of Lithodora rosmarinifolia (Ten.) Johnst., a rare, endemic Mediterranean species

2012

In this study, we investigated the possibility of using the droplet-vitrification technique for cryopreserving nodal segments of in vitro plantlets of the endangered plant species Lithodora rosmarinifolia. Among the three vitrification solutions tested, only solutions B1, containing (w/v) 50 % glycerol and 50 % sucrose, and B3, containing 40 % glycerol and 40 % sucrose, were able to induce cryotolerance in nodal explants, resulting in intermediate survival and recovery after cryopreservation. A three-step vitrification protocol, including an additional dehydration treatment with half-strength vitrification solution for 30 min before the treatment with full-strength vitrification solution, d…

Cryopreservation of Limonium serotinum apical meristems from in vitro plantlets using droplet-vitrification

2011

Abstract In this study in vitro shoot tips of a Sicilian genotype of Limonium serotinum were successfully cryopreserved using the droplet-vitrification technique. Growth recovery of cryopreserved shoot tips was possible only when samples were pretreated for 16 h in liquid medium with 0.3 M sucrose, then for 5 h in liquid medium with 0.7 M sucrose before performing the cryopreservation protocol. Optimal conditions included treatment for 20 min in a loading solution containing 1.9 M glycerol + 0.5 M sucrose, treatment with vitrification solution B5 (glycerol 40.0%, sucrose 40.0%, w/v) for 60 and 90 min or vitrification solution A9 (glycerol 30.0%, dimethylsulfoxide 20.0%, ethylene glycol 20.0…

Structural effects of macrocyclic compounds and their partition in sodium dodecylsulphate aqueous solutions

2003

The partition of 1,4,7,10,13,16-esaoxacyclooctadecane (18C6), 4,7,13,16-tetraoxa-1,10-diazacyclooctadecane (2.2), 2,5,8,11,14,17-esaoxabicyclo[16.4.0]dicosane (B18C6) and 2,5,8,15,18,21-esoxatricyclo[20.4.0.09.14]esacosane (Cy218C6) in sodium dodecyl sulfate (SDS) aqueous solutions and their effect on the structure of surfactant aggregates has been investigated by small-angle neutron scattering. Results from data analysis have shown that by increasing macrocycle concentration the SDS micelles dimensions reduce for all systems investigated. At the same time information on macrocycles partition between the micellar and the continuous phase have been obtained. It was found that an appreciable …

Ab initio calculations of SrTiO3, BaTiO3, PbTiO3, CaTiO3, SrZrO3, PbZrO3 and BaZrO3 (001), (011) and (111) surfaces as well as F centers, polarons, K…

2014

In this paper, the review of recent results of calculations of surface relaxations, energetics, and bonding properties for ABO 3 perovskite (001), (011) and (111) surfaces using mostly a hybrid description of exchange and correlation is presented. Both AO and BO 2-terminations of the nonpolar (001) surface and A , BO , and O terminations of the polar (011) surface, as well as B and AO 3-terminations of the polar (111) surface were considered. On the AO -terminated (001) surface, all upper-layer A atoms relax inwards, while all second layer atoms relax outwards. For the BO 2-terminated (001) surface, in most cases, the largest relaxations are on the second-layer metal atoms. For almost all …

<title>High-excitation-density luminescence as probe of mixed silver halides</title>

1992

Two kinds of intrinsic luminescence in mixed AgBr1-xClx (1 io. Dependence of the parameters of this process on crystal composition has been investigated in terms of spatially well correlated Frenkel defect recombinations. The main effect found was the linear increase of the Agio migration energy with the crystal composition x. The second kind of luminescence arising due to exciton molecules has been shown to be sensitive to the solid solution composition and the quality of a crystal. It is shown that this luminescence correlates with the optical losses of the fibers studied.

Computational stability of an initially radial solution of a growth/dissolution problem in a nonradial implementation

1991

We consider a free boundary problem modelling the growth/dissolution of a crystal. The aim is to investigate the following question: Does the solution to the crystal growth problem posed in two dimensions with radially symmetric initial and boundary condition evolve as a radially symmetric solution?

Effect of Hydrostatic Pressure on the Phase Transitions of {N(CH3)4}2ZnCl4-xBrxMixed Crystals

1991

Single crystals of the solid solution system {N(CH 3 ) 4 } 2 ZnCl 4- x Br x have been prepared in a low x region, and the effect of hydrostatic pressure on the phase transitions were measured for x =0.2 and 0.3. The normal-to-incommensurate phase transition temperatures increase linearly with increasing pressure with the rates of 0.126 K/MPa and 0.129 K/MPa for x =0.2 and 0.3 crystals, respectively. The ferroelectric III phase disappears at about 60 MPa for x =0.2 crystal. On the other hand, phase III is not observed for the x =0.3 crystal both at 0 pressure and at high pressures. The II-IV or III-IV transition temperatures also increases with increasing pressure with the rates of 0.162 K/M…

Morphotropic ceramic solid solutions of the Pb(B3+½Nb½)O3- PbTiO3binary system

2000

Abstract The structure, dielectric, ferroelectric and electromechanical properties of lead lutecium niobate-titanate (PLuNT) and lead erbium niobate-titanate (PErNT) binary systems are reported. The data of phase diagram, crystallographic symmetry and morphotropic phase boundaries (MPB) are provided. High values of the electromechanical coupling coefficients kp = 0.66, kt = 0.48, k31 = 0.36 of (1−x)PLuN − xPT ceramics are attained in compositions near the MPB at x≈0.41.

Ab initio calculations of the Ni K ‐edge XANES in Ni c Mg 1‐c O solid solutions

2005

An interpretation of the Ni K-edge X-ray absorption near edge structure (XANES) in pure NiO and NicMg1-cO solid solutions is given based on three types of ab initio theoretical calculations: the full-multiple-scattering (FMS) approach, the finite difference method (FDM) and the full potential linear muffin-tin orbital (FP-LMTO) method within the LSDA+U approach. The first two methods differ in the cluster potential approximation: the spherically symmetric muffin-tin potential is used in the FMS approach, whereas a non-muffin-tin numerical potential makes the core of the FDM. We found that the FMS and FDM techniques allow rather accurate description of the experimental XANES signal especiall…