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Computer modeling and description of nonstoichiometric apatites Cd5-η/2(VO4)3I1-η and Cd5-η/2(PO4)3Br1-η as modified chimney-ladder structures with ladder-ladder and chimney-ladder coupling

Diffraction patterns from apatite-structure compounds Cd5-η/2(TO4)3X1-η with T=P, V and X=Br, I show sheets of diffuse scattering normal to c* at incommensurate l=q (q=1.63 for Cd-V-I apatite and q=1.78 for Cd-P-Br apatite), because the c repeat of the average unit cell is shorter than two X diameters. The equilibrium X..X spacing along c defines the incommensurate periodicity c/q and stoichiometr

Gallium and indium under high pressure

A study was carried out to explore the structural competition between the high symmetry fcc and low symmetry bct structure for the IIIA metals Al, Ga, and In. It was found that the competition originates from electronic properties. As a result, the high pressure behavior of the metals appears reversed to the corresponding-states rule.

Single crystsl refinement of the incommensurately modulated Mn0.55Ta0.45O1.7, an oxygen deficient fluorite type compound

A structural investigation of the incommensurately ordered compound Mn0.55Ta0.45O1.7 has been carried out, using single-crystal X-ray diffraction data. The basic structure is related to the fluorite type with a monoclinic distortion. Electron diffraction (ED) patterns for various crystal orientations were used for determination of unit cell, incommensurate modulation vector and superspace group. T

Reassessing the compound CeCd6 : the structure of Ce6Cd37

The crystal structure of the phase Ce6Cd37 was determined by single-crystal X-ray diffraction. It is closely related to, and indeed probably identical to, the previously reported compound CeCd6. The compound crystallizes in the centrosymmetric space group Pn3̄ with the unit cell axis 15.808(2) angstrom. The structure may be described by successive shells centered around the origin and the position

On the question of commensurability - The Nowotny chimney-ladder structures revisited

A composite approach was used for the structure solution and refinement of two new Nowotny chimney-ladder phases, (Mo/Rh)11Ge18 and (Mo/Rh)13Ge22, found during investigations in the Mo/Rh/Ge system. The descriptions of the phases with conventional models (in I4̄2d (No. 122) with a = 5.885(2) Å, c = 52.62(2) Å for (Mo/Rh)11Ge18 and a = 5.922(1) Å, c = 62.88(4) Å for (Mo/Rh)13Ge22) led to high numbe

Incommensurately modulated cadmium apatites

Two cadmium apatites, Cd5(PO4)3Br and Cd5(VO4)3I, earlier reported to be halogenide deficient, were prime suspects of being modulated. In this study, incommensurate ordering was found in satellites occurring in planes perpendicular to c*. The structure of Cd5(PO4)3Br was refined from single-crystal X-ray diffraction data in the four-dimensional super space group R:P3̄:(00γ): a = 16.932(2) Å, c = 6

Electrical resistivity of one-dimensional quasiperiodic η8-Cu5Sn4

The electrical resistivity, ρ, of one-dimensional quasiperiodic η8-Cu5Sn4 has been studied, and compared with crystalline Cu6Sn5 of identical basic structure (B8) and closely related atomic structure. ρ was measured between 1.5 and 300 K on needle-shaped crystals with their axes along the base lattice c direction, corresponding to the quasiperiodic direction in η8-Cu5Sn4. ρ (4 K) was found to be n

Iodo-oxyapatite, the first example from a new class of modulated apatites

Iodo-oxyapatite [pentadecacalcium iodide oxide nonaphosphate, Ca15(PO4)9IO] was synthesized by a flux method and the structure was solved from single-crystal X-ray data. The crystal structure was refined in the space group P63/m [a = 9.567 (1), c = 20.754 (2) Å and Z = 2] to wR on F of 0.0459. Iodo-oxyapatite has a typical hexagonal apatite structure but the unit cell is tripled along the hexad ow

The origin of the distorted close-packed elemental structure of indium

Why does indium adopt a tetragonally distorted fcc structure, and not a fcc structure like its lighter homologue aluminum? This question has puzzled chemists and physicists for a long time, and has now been addressed by means of ab initio full-potential calculations in the framework of density functional theory. It was found that the different tendency of aluminum and indium to form s-p hybridized

On the first incommensurate ordering of NH4Cu7-xS4

The first incommensurate ordering of NH4Cu7-xS4 (x = 0.16) has been investigated using X-ray single crystal diffraction at 174 K. The modulated structure is described with monoclinic symmetry with the cell parameters a = 10.272 (angstrom), b = 10.272 (angstrom), c = 7.694 (angstrom) and β=90.0°. It belongs to the four-dimensional space group P:P2/n:-11 {conventional setting P:P2/b:-11 (no. 13.1)}.

Growing and Characterizing Biofilms Formed by Streptococcus pneumoniae

It is estimated that over 80% of bacterial infections are associated with biofilm formation. Biofilms are organized bacterial communities formed on abiotic surfaces, such as implanted or inserted medical devices, or on biological surfaces, such as epithelial linings and mucosal surfaces. Biofilm growth is advantageous for the bacterial organism as it protects the bacteria from antimicrobial host f

Tracing livelihood trajectories : Patterns of livelihood adaptations in rural communities in eastern Nepal

Mountain communities are adapting their livelihoods to a complex combination of social, political and economic changes and associated risks. Despite recognition of adaption in response to multiple changes in sustainable livelihood and critical climate change literature, risks attributed to biophysical effects of climate change have increasingly assumed importance. Consequently, diversification is

Conflicts in adaptation : Case studies from Nepal and the Maldives

Purpose – Adaptation appears to be regarded as a panacea in policy circles to reduce the risk of impending crises resulting from contemporary changes, including but not restricted to climate change. Such conceptions can be problematic, generally assuming adaptation as an entirely positive and non-conflictual process. The purpose of this paper is to challenge such uncritical views, drawing attentio

Gendered consequences of mobility for adaptation in small island developing states : Case studies from Maafushi and Kudafari in the Maldives

In recent years island communities have actively adapted in response to a complex combination of changes that has shaped life on the islands, and this has had gendered consequences. The gender ramifications of adaptation on islands are still largely neglected in adaptation policies, although they are increasingly being addressed in the scientific literature. Understanding gendered consequences is

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During the communist dictatorship, police and detectivistic literature was an amphibious species, and had to hide rather than to embrace courageous assumptions. In the multilateral developed socialism (for communism has never been reached), criminals and criminals were urgently annihilated and then exposed to public atrocities. All the strategy based on the propaganda for the ideological success,