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1.
Phase Relations and Sodium Ion Conductivity within the Quasi-binary System Na2SiF6/Na2AIF6 . The phase diagram of the Na2SiF6/Na3AlF6 system has been determined by means of x-ray powder diffraction, thermal analysis and conductivity measurements in the sub-solidus region. Na3AlF6 accomodates up to 73 mol.-% Na2SiF6 maintaining the crystal structure type. The sodium ion conductivity increases by about five orders of magnitude upon doping Na3AlF6 with Na2SiF6. 相似文献
2.
Evolutionary algorithms are applied as problem-independent optimization algorithms. They are quite efficient in many situations. However, it is difficult to analyze even the behavior of simple variants of evolutionary algorithms like the (1+1) EA on rather simple functions. Nevertheless, only the analysis of the expected run time and the success probability within a given number of steps can guide the choice of the free parameters of the algorithms. Here static (1+1) EAs with a fixed mutation probability are compared with dynamic (1+1) EAs with a simple schedule for the variation of the mutation probability. The dynamic variant is first analyzed for functions typically chosen as example-functions for evolutionary algorithms. Afterwards, it is shown that it can be essential to choose the suitable variant of the (1+1) EA. More precisely, functions are presented where each static (1+1) EA has exponential expected run time while the dynamic variant has polynomial expected run time. For other functions it is shown that the dynamic (1+1) EA has exponential expected run time while a static (1+1) EA with a good choice of the mutation probability has polynomial run time with overwhelming probability. 相似文献
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Synthesis and Structure of K3N Two phases in the binary system K/N have been obtained via co‐deposition of potassium and nitrogen onto polished sapphire at 77 K and subsequent heating to room temperature. The powder diffraction pattern of one of these phases can be satisfactorily interpreted by assuming the composition K3N, and the anti‐TiI3 structure‐type, which is also adopted by Cs3O. The resulting hexagonal lattice constants are: a = 779.8(2), c = 759.2(9) pm, Z = 2, P63/mcm. Comparison with possible structures of K3N generated by computational methods and refined at Hartree‐Fock‐ and DFT level, reveals that the energetically most favoured structure has not formed (presumable Li3P‐type), but instead one of those with very low density. In this respect, the findings for K3N are analogous to the results on Na3N. The thermal evolution of the deposited starting mixture has been investigated. Hexagonal K3N transforms to another K/N phase at 233 K. Its XRD can be fully indexed resulting in an orthorhombic cell a = 1163, b = 596, c = 718 pm. Decomposition leaving elemental potassium as the only residue occurs at 263 K. 相似文献
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By reacting platinum with alkali metals (A = K, Rb, Cs) a new family of binary alkali metal platinides has been synthesized and characterized by chemical analysis, X‐ray powder diffraction, thermal analysis (DTA and DSC), and magnetic measurements. All three compounds exhibit similar XRD‐patterns with strong reflections that can be indexed on the basis of a rhombohedral crystal system (KxPt: a = 2.6462(1), c = 17.123(1); RbxPt: a = 2.6415(1) Å, c = 17.871(1) Å; CsxPt: a = 2.6505(1) Å, c = 18.536(1) Å; x < ½. The a lattice constant is independent on the alkali metal used and of value close to the Pt–Pt distance in NaPt2 (2.645Å). The c parameter increases monotonically with the growing atomic radius of the alkali metal. The average structure of the alloys consists of cubic close packed layers of platinum atoms with layers of disordered alkali metals in between. For all compounds besides the strong reflections small satellites are observed which cannot be indexed together with the rhombohedral peaks in any rational 3‐dimensional lattice. However, these satellites can be indexed as incommensurate modulations within the ab plane (found propagation vectors k = (0.1011, 0.2506, 0) for CsxPt, and k = (0.0168, 0.2785, 0) for RbxPt). 相似文献
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Nitrido-Sodalites. II. Synthesis, Crystal Structure, and Properties of M(6+(y/2)–x)H2x[P12N24]Zy with M = Fe, Co, Ni, Mn; Z = Cl, Br, I; 0 ≤ x ≤ 4; y ≤ 2 The nitrido sodalites M(6+(y/2)–x)H2x[P12N24]Zy with M = Fe, Co, Ni, Mn; Z = Cl, Br, I; 0 ≤ x ≤ 4; y ≤ 2 are obtained by the reaction of HPN2 or [PN(NH2)2]3 with the metal halogenide MZ2 (T = 700°C). The compounds are isotypic to Zn(7–x)H2x[P12N24]Cl2. An increase of the ionic radii of the cations or anions results in an expansion of the lattice which is caused by an increase of the P? N? P angle. The influence of the cation is more dominant than that of the anion. By reacting [PN(NH2)2]3 with metal halogenide (MZ2) hydrogen free, X-ray amorphous products are obtained. The formation of the chloride-containing P? N-sodalite in this reaction begins at temperatures below 450°C. 相似文献
10.
Jan F. Keij Jan Th . M. Jansen Frank W. Schultz Jan W. M. Visser 《Photochemistry and photobiology》1994,60(5):503-509
Abstract-During the development of a photodamage cell sorter several photosensitizers were tested for their ability to photoinactivate more than 90% of the sensitized cells after a brief irradiation with a fluence of 10 kJ/m2 . In pilot experiments, yeast cells sensitized with 10-dodecyl acridine orange (DAO) were effectively photoinactivated after receiving a fluence of 10 kJ/m2 delivered in 8 s. However, when the same fluence was delivered in 3 μ s during passage through a focused laser beam in the cell sorter, all cells survived.
Computer simulations of the relevant photophysical and chemical reactions inside the irradiated cell were used to investigate the cause of this phenomenon. The results indicated that the absence of photoinactivation by DAO, after flash irradiations, was caused by the combined effects of (1) limited oxygen diffusion into the cell and (2) a reduced number of collisions between photosensitizer triplet and oxygen molecules during the irradiation due to saturation of the intracellular photosensitizer triplet concentration. The contributions of triplet-triplet annihilation and triplet quenching by ground state photosensitizer molecules were found to be minimal and not significant. These findings indicate that Type II photosensitizers are incapable of rapid selective photoinactivation in cell sorters. 相似文献
Computer simulations of the relevant photophysical and chemical reactions inside the irradiated cell were used to investigate the cause of this phenomenon. The results indicated that the absence of photoinactivation by DAO, after flash irradiations, was caused by the combined effects of (1) limited oxygen diffusion into the cell and (2) a reduced number of collisions between photosensitizer triplet and oxygen molecules during the irradiation due to saturation of the intracellular photosensitizer triplet concentration. The contributions of triplet-triplet annihilation and triplet quenching by ground state photosensitizer molecules were found to be minimal and not significant. These findings indicate that Type II photosensitizers are incapable of rapid selective photoinactivation in cell sorters. 相似文献