Search

Using surface‐templated electrophoretic deposition, arrays of polymer beads (photonic units) incorporating photo‐switchable DAE molecules are created, which can be reversibly and individually switched between high and low emission states by direct photo‐excitation, without any energy or electron transfer processes within the molecular system. The micropatterned array of these photonic units is spectroscopically characterized in detail and optimized with respect to both signal contrast and cross‐talk. The optimum optical parameters including laser intensity, wavelength and duration of irradiation are elucidated and ideal conditions for creating reversible on/off cycles in a micropatterned array are determined. 500 such cycles are demonstrated with no obvious on/off contrast attenuation. The ability to process binary information is demonstrated by selectively writing information to the given photonic unit, reading the resultant emissive signal pattern and finally erasing the information again, which in turn demonstrates the possibility of continuous recording. This basic study paves the way for building complex circuits using spatially well‐arranged photonic units. [ABSTRACT FROM AUTHOR]

To design an effective battery thermal management system, multiple simulations with different levels of modeling, physics, and details are generally needed. However, complex and high‐resolution models are time‐consuming, both in terms of buildup and in computation time. Especially the fast‐moving early‐stage development phases demand all‐in‐one model approaches allowing for quick and efficient concept evaluations. To meet these requirements, herein, a lumped‐mass modeling approach is proposed and a methodology for evaluating various liquid cooling plate topologies is derived. The framework aims to assist the volatile concept phase of battery system development in providing multidimensionally optimized cooling plate topologies. A novel modeling strategy preselects plate parameters using a reduction procedure that couples the transient models' accuracy with the steady‐state models' computation time advantages. The results analyze different initial battery geometries, indicating significant deviations in their optimized cooling plate properties. Plate topologies are varied between their main construction design parameters: tube size and tube‐to‐tube distance. In addition to battery's mean temperature, further meaningful parameters like resulting volume flow are evaluated, compared, and discussed for the entire set of battery geometries. Subsequent sensitivity analyses show geometry‐related optimal plate topologies depending on the cooling circuit performance, stressing the necessity for early‐stage cooling plate investigations. [ABSTRACT FROM AUTHOR]

Infrared thermography of brazed plate heat exchangers for evaporators and condensers recently was used to quantify maldistribution. With the knowledge of the secondary fluids heat transfer coefficient and a given secondary fluids distribution, the local heat transfer coefficient of the primary fluid (refrigerant) and its distribution to the channels can be calculated. A sensitivity analysis shows ± 10 % difference of the surface temperature to the wall center temperature at the expected ratios of heat transfer coefficients. The method is presented in this paper using an exemplary infrared picture. [ABSTRACT FROM AUTHOR]

The crystal structure of the new ternary phosphideTm5Pd9P7 was determined from powder X‐ray diffraction data: space group P6‾ , a=9.9971(2), c=3.94371(8) Å, RI=0.0518, Rp=0.0667, Rp=0.0667, wRp=0.1065. The crystal structure of the phosphide Tm5Pd9P7 is closely related with the Zr2Fe12P7‐type, and is formed by combination of two types of structural units with the compositions [TmPd6P3] and [TmTm3Pd3P3] mutually displaced by 1/2 along the c axis. Connection of the last units forms the trigonal prisms [Tm6] around P3 atoms in the crystallographic position 1a (0 0 0). The isotypic ternary phosphide Lu5Pd9P7 was synthesized (a=9.9934(7), c=3.9207(4) Å). The electronic and bonding properties of Tm5Pd9P7 are obtained from tight binding linear muffin‐tin orbital (TB‐LMTO) calculations and a crystal orbital Hamiltonian population (COHP) bonding analysis. These analyses show strong covalent bonding within (Pd9P7)15− nanotubes which are ionically bound via the Tm atoms to three dimensional network. [ABSTRACT FROM AUTHOR]

Unusual structural colors are demonstrated in thin‐film coatings due to a combination of optical interference and light scattering effects. These vivid colors are concealed under ambient illumination but can be observed when light is reflected from the film surface. The origin of the effect is explored computationally and it is shown that, in thin‐films of lossless dielectrics coated on near‐perfect conductors, incident electromagnetic waves form standing waves. Electric field intensities at the thin film interfaces are maximized for wavelengths that fulfil destructive interference conditions, while nanoscale roughness can enhance scattering at these boundaries. The interplay of these two factors yields vivid, thickness‐dependent colors. This approach increases the repertoire of optical effects and perceived colors in thin coatings. When combined with traditional thin‐film interference colours, dichromatic images with distinctly changing colors can be generated, which can function as a covert, optical security feature. [ABSTRACT FROM AUTHOR]

Hypercholesterolaemia is a major cardiovascular risk factor. A healthy diet and a healthy lifestyle reduces cardiovascular risk. 'Functional foods' supplemented with phytosterols are recommended for the management of hypercholesterolaemia and have become a widely used non-prescription approach to lower plasma cholesterol levels. Two billion euros are spent world-wide each year on various functional foods, which have regulator-approved health claims for the management of elevated cholesterol levels. While international societies, such as the European Atherosclerosis Society or the National Heart Foundation in Australia, still advise phytosterols as an additional dietary option in the management of hypercholesterolaemia, recently released guidelines such as those from the National Institute of Health and Clinical Excellence in the United Kingdom are more critical of food supplementation with phytosterols and draw attention to significant safety issues. This review challenges whether an intervention with phytosterol supplements is beneficial. We summarize the current evidence from genetic diseases, genetic association studies, clinical trial data and data from animal studies.Linked Articles: This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc. [ABSTRACT FROM AUTHOR]

A big challenge for nonlinear optical (NLO) materials is the application in high power lasers, which needs the simultaneous occurrence of large second harmonic generation (SHG) and high laser induced damage threshold (LIDT). Herein we report the preparation of a new Ga2Se3 phase, which shows the SHG intensities of around 2.3 times and the LIDT of around 16.7 times those of AgGaS2 (AGS), respectively. In addition, its IR transparent window ca. 0.59–25 μm is also significantly wider than that of AGS (ca. 0.48–≈11.4 μm). The occurrence of the strong SHG responses and good phase‐matching indicate that the structure of the new Ga2Se3 phase can only be non‐centrosymmetric and have a lower symmetry than the cubic γ‐phase. The observed excellent SHG and phase‐matching properties are consistent with our diffraction experiments and can be well explained by using the orthorhombic models obtained through our high throughput simulations. [ABSTRACT FROM AUTHOR]

This study presents the first laser porosificated silicon anode for lithium-ion batteries. The pulsed laser induced pore creation improves the cycling stability of the d = 210 nm thick sputtered thin film anodes compared to plain Si. Galvanostatic cycling with a charge capacity limited to C = 932 mAh g−1 and a 2 C current rate shows a stable cycling for more than N = 600 cycles. After N = 3000 cycles the laser porosificated and crystallized Si has a remaining capacity of C3000 > 120 mAh g−1. Postmortem scanning electron microscopy images after N = 3000 cycles prove that the laser porosification reduces cracks in the active layer. [ABSTRACT FROM AUTHOR]

The transport of excitation energy in molecular aggregates is of crucial importance for the function of organic optoelectronic devices and next-generation solar cells. First, this review summarizes the theoretical background of the nature of the electronically excited states of molecular aggregates. For these systems, the electronic interaction between the monomers leads to the formation of exciton states. This goes along with a shift of the excitation energies and a redistribution of the oscillator strength with respect to the monomers. Next, a brief overview is provided over experimental techniques that allow to study the properties of excitons in molecular aggregates. This includes single-molecule spectroscopy, coherent two-dimensional (2D) spectroscopy, and single-molecule coherent spectroscopy. Finally, examples of molecular aggregates spanning the range from natural systems that act in photosynthesis as light-harvesting antennas to artificial aggregates built from synthetic chromophores are illustrated. [ABSTRACT FROM AUTHOR]

We explored under what conditions perovskite oxides ABO3 adopt a polar or an antiferrodistortive structure from the viewpoint of the tolerance factor τ and the orbital interactions of the empty orbitals of the A and B cations with the filled orbitals of their surrounding O2- ions. Polar structures require the presence of a substantial size-mismatch as well as strong cation-anion orbital interactions at A or B cation sites. A tetragonal polar structure is preferred when the A cation empty orbitals are extended or when the B-cation empty orbitals are contracted. A trigonal polar structure is favored in opposite cases. An antiferrodistortive structure is found for perovskites with weak size-mismatch or those with substantial size-mismatch if both A and B cations do not generate strong cation-anion orbital interactions. Antiferrodistortive structures result from interactions involving the A cations with the O4 squares of the face-sharing AO8 square-prisms in a two-in-two-out manner, and are found only when the A/O cation-anion interactions are substantial. [ABSTRACT FROM AUTHOR]

The new ternary intermetallic phase, BaPtCd2, was synthesized by solid-state reaction from direct combination of the elements in a stoichiometric mixture. The reaction was done at 850 °C for 15 h, followed by an equilibration at 600 °C for 4 d. The crystal structure was determined by X-ray diffraction method on a single crystal. BaPtCd2 is isotypic to MgCuAl2 and crystallizes in the orthorhombic space group Cmcm [ a = 4.467(2), b = 11.143(4), c = 8.240(3) Å, V = 410.2(3) Å3, and Z = 4]. Barium atoms are linked together forming zigzag chains. Cadmium atoms are bonded to each other forming six-membered rings of platinum centered boat and anti-boat conformations. BaPtCd2 contains 16 electrons per formula unit and belongs to the electron poorest compounds with MgCuAl2 type structure. Calculations based on the linear muffin-tin orbitals method in the atomic spheres approximation show that significant bonding states in BaPtCd2 are unoccupied. [ABSTRACT FROM AUTHOR]

The new ternary intermetallic phase, BaPtCd2, was synthesized by solid-state reaction from direct combination of the elements in a stoichiometric mixture. The reaction was done at 850 °C for 15 h, followed by an equilibration at 600 °C for 4 d. The crystal structure was determined by X-ray diffraction method on a single crystal. BaPtCd2 is isotypic to MgCuAl2 and crystallizes in the orthorhombic space group Cmcm [ a = 4.467(2), b = 11.143(4), c = 8.240(3) Å, V = 410.2(3) Å3, and Z = 4]. Barium atoms are linked together forming zigzag chains. Cadmium atoms are bonded to each other forming six-membered rings of platinum centered boat and anti-boat conformations. BaPtCd2 contains 16 electrons per formula unit and belongs to the electron poorest compounds with MgCuAl2 type structure. Calculations based on the linear muffin-tin orbitals method in the atomic spheres approximation show that significant bonding states in BaPtCd2 are unoccupied. [ABSTRACT FROM AUTHOR]

The dynamical properties of EuTiO3 are investigated to gain insight into its precursor effects analogous to those observed in many other perovskite oxides. In spite of the fact that a competition between the long wave length transverse optic mode and the zone boundary acoustic mode is absent, which makes the mode-mode coupling inessential, acoustic instabilities on limited spatial regions appear well above TS. This confirms the notion that dynamic forerunners are inherent and precede any phase transition in cubic perovskite oxides. [ABSTRACT FROM AUTHOR]

The dynamical properties of EuTiO3 are investigated to gain insight into its precursor effects analogous to those observed in many other perovskite oxides. In spite of the fact that a competition between the long wave length transverse optic mode and the zone boundary acoustic mode is absent, which makes the mode-mode coupling inessential, acoustic instabilities on limited spatial regions appear well above TS. This confirms the notion that dynamic forerunners are inherent and precede any phase transition in cubic perovskite oxides. [ABSTRACT FROM AUTHOR]

Four lanthanide(III) nitride bismuthides of the new class M2NBi ( M = La-Nd) have been synthesized by the reaction of the respective lanthanide metal ( M) with caesium azide (CsN3), elemental bismuth (Bi), the corresponding lanthanide trichloride ( MCl3), and caesium chloride (CsCl) as flux in evacuated silica tubes for 7 days at 900 °C. The M2NBi compounds crystallize tetragonally in the space group P4/ nmm with Z = 2 with the lattice parameters a = 480.61(4) pm, c = 948.34(9) pm ( M = La), a = 475.48(4) pm, c = 938.76(9) pm ( M = Ce), a = 471.80(4) pm, c = 929.51(9) pm ( M = Pr), and a = 468.13(4), c = 921.08(9) pm ( M = Nd). As the main structural feature of the crystal structures, ∞2{[N M2]3+} layers of condensed nitride-centered square pyramids of M3+ cations dominate. These pyramids, in which the base is built of ( M1)3+ and the top of terminal ( M2)3+ cations ( t), are connected by all four basal edges ( e) to form a two-dimensional network according to ∞2{[N( M1) e4/4( M2) t1/1]3+} that is separated by square double layers of Bi3- anions. Both crystallographically independent M3+ cations bear two types of anions (N3- and Bi3-) as ligands. ( M1)3+ is coordinated in the shape of a square antiprism by four N3- and four Bi3- anions, and ( M2)3+ is surrounded by a distorted octahedron consisting of one N3- and five Bi3- anions. The Bi3- anions reside in capped square antiprisms of nine M3+ cations. The partial density of states (PDOS) and the band structure of La2NBi show that this compound has to be considered as a zero-band-gap semiconductor with a nontrivial topology and a high potential as a topological insulator. [ABSTRACT FROM AUTHOR]

The new low valent iridiumindiumoxogallate Ir2In12Ga4O15 was prepared by heating intimate mixtures of Ir, In, In2O3, and Ga2O3 in a platinum crucible under an atmosphere of argon (1400 K, 70 h). The compound has an orange color. X-ray powder diffraction patterns can be indexed on the basis of a primitive orthorhombic unit cell with lattice parameters a = 1954.5(1) pm, b = 674.0(1) pm, and c = 745.9(1) pm. The crystal structure of Ir2In12Ga4O15 was solved from powder diffraction data and refined using the Rietveld method ( Pnn2, R(prof.) = 4.4 %, R(int.) = 2.5 %). Ir2In12Ga4O15 is according to [IrIn5In2/2]9+2[GaO4]5-2[Ga2O7]8- an ortho-gallate- pyro-gallate with chains of corner sharing [IrIn7]9+ polyhedra, [GaO4]5-2 tetrahedra, and [Ga2O7]8- double tetrahedra. The Ir-In distances within the IrIn7 polyhedra are shorter than in Ir-In intermetallic phases and lie between 256-261 pm. [ABSTRACT FROM AUTHOR]

The new low valent iridiumindiumoxogallate Ir2In12Ga4O15 was prepared by heating intimate mixtures of Ir, In, In2O3, and Ga2O3 in a platinum crucible under an atmosphere of argon (1400 K, 70 h). The compound has an orange color. X-ray powder diffraction patterns can be indexed on the basis of a primitive orthorhombic unit cell with lattice parameters a = 1954.5(1) pm, b = 674.0(1) pm, and c = 745.9(1) pm. The crystal structure of Ir2In12Ga4O15 was solved from powder diffraction data and refined using the Rietveld method ( Pnn2, R(prof.) = 4.4 %, R(int.) = 2.5 %). Ir2In12Ga4O15 is according to [IrIn5In2/2]9+2[GaO4]5-2[Ga2O7]8- an ortho-gallate- pyro-gallate with chains of corner sharing [IrIn7]9+ polyhedra, [GaO4]5-2 tetrahedra, and [Ga2O7]8- double tetrahedra. The Ir-In distances within the IrIn7 polyhedra are shorter than in Ir-In intermetallic phases and lie between 256-261 pm. [ABSTRACT FROM AUTHOR]

The synthesis and photophysical properties of two novel multichromophoric compounds is presented. Their molecular design comprises a carbonyl-bridged triarylamine core and either naphthalimides or 4-(5-hexyl-2,2′-bithiophene)naphthalimides as second chromophore in the periphery. The lateral chromophores are attached to the core via an amide linkage and a short alkyl spacer. The synthetic approach demonstrates a straightforward functionalization strategy for carbonyl-bridged triarylamines. Steady-state and time-resolved spectroscopic investigations of these compounds, in combination with three reference compounds, provide clear evidence for energy transfer in both multichromophoric compounds. The direction of the energy transfer depends on the lateral chromophore used. Furthermore, the compound bearing the lateral 4-(bithiophene)naphthaimides is capable of forming fluorescent gels at very low concentrations in the sub-millimolar regime whilst retaining its energy transfer properties. [ABSTRACT FROM AUTHOR]

Sequenzen von hochaufgelösten Tieftemperaturemissionsspektren einzelner LH2 ‐ Lichtsammelkomplexe von Rhodopseudomonas acidophila zeigen eine deutlich größere Vielfalt an Emissionsprofilen als zuvor beobachtet. Die Ergebnisse liefern einen direkten Beleg für beträchtliche Fluktuationen in der Elektron ‐ Phonon ‐ Kopplung und, verbunden damit, der Excitonen(de)lokalisierung innerhalb einzelner Pigment ‐ Protein ‐ Komplexe. [ABSTRACT FROM AUTHOR]

Pigeon blood red powder samples of SnO were synthesized via a soft chemistry route. A precipitate was obtained from a freshly prepared SnCl2 solution containing phosphorus acid by adding ammonia until a pH value of 4.9 is reached. Heating of the mixture at 95 °C leads after 5 d to microcrystalline powders of red SnO. The crystal structure was solved and refined from X-ray powder diffraction data ( Cmc21; a = 5.0045(3) Å, b = 5.7457(3) Å, c = 11.0485(5) Å, Z = 8). Red SnO crystallizes in a new structure type. Characteristic building units are double layers of tin and oxygen atoms. The tin atoms are surrounded by four oxygen atoms with distances ranging from 2.04 Å to 2.67 Å, and the highly asymmetric coordination around the Sn2+ ions indicates the presence of a stereochemically active lone pair. LMTO band structure calculations show that the red modification of SnO is an insulator. The electronic structures of red SnO and the zero band gap semiconductor black SnO are compared. The lone pairs of the tin atoms are visualized via the electron localization function. [ABSTRACT FROM AUTHOR]

Orchid colored powder samples of Cs2AgF4 were prepared by a solid state reaction from CsF and AgF2. The diffuse reflectance spectrum of a powder sample of Cs2AgF4 was measured in the UV/Vis region. It shows three broad bands, two in the visible-light region at 650 nm, 500 nm and one in the UV region at 259 nm. The bands are assigned to F 2p → Ag 4d and Ag 4d → Ag 4d transitions. The optical band gap for Cs2AgF4 determined from the UV/Vis diffuse reflectance spectrum is approx. 2.17 eV. In order to interpret the observed absorptions, the theoretical absorption spectrum of Cs2AgF4 was obtained from density functional calculations. [ABSTRACT FROM AUTHOR]

Orchid colored powder samples of Cs2AgF4 were prepared by a solid state reaction from CsF and AgF2. The diffuse reflectance spectrum of a powder sample of Cs2AgF4 was measured in the UV/Vis region. It shows three broad bands, two in the visible-light region at 650 nm, 500 nm and one in the UV region at 259 nm. The bands are assigned to F 2p → Ag 4d and Ag 4d → Ag 4d transitions. The optical band gap for Cs2AgF4 determined from the UV/Vis diffuse reflectance spectrum is approx. 2.17 eV. In order to interpret the observed absorptions, the theoretical absorption spectrum of Cs2AgF4 was obtained from density functional calculations. [ABSTRACT FROM AUTHOR]

At ultrahigh pressure (>110 GPa), H2S is converted into a metallic phase that becomes superconducting with a record Tc of approximately 200 K. It has been proposed that the superconducting phase is body-centered cubic H3S (Im m, a=3.089 Å) resulting from the decomposition reaction 3 H2S→2 H3S+S. The analogy between H2S and H2O led us to a very different conclusion. The well-known dissociation of water into H3O+ and OH− increases by orders of magnitude under pressure. H2S is anticipated to behave similarly under pressure, with the dissociation process 2 H2S→H3S++SH− leading to the perovskite structure (SH−)(H3S+). This phase consists of corner-sharing SH6 octahedra with SH− ions at each A site (the centers of the S8 cubes). DFT calculations show that the perovskite (SH−)(H3S+) is thermodynamically more stable than the Im m structure of H3S, and suggest that the A site hydrogen atoms are most likely fluxional even at Tc . [ABSTRACT FROM AUTHOR]

At ultrahigh pressure (>110 GPa), H2S is converted into a metallic phase that becomes superconducting with a record Tc of approximately 200 K. It has been proposed that the superconducting phase is body-centered cubic H3S (Im m, a=3.089 Å) resulting from the decomposition reaction 3 H2S→2 H3S+S. The analogy between H2S and H2O led us to a very different conclusion. The well-known dissociation of water into H3O+ and OH− increases by orders of magnitude under pressure. H2S is anticipated to behave similarly under pressure, with the dissociation process 2 H2S→H3S++SH− leading to the perovskite structure (SH−)(H3S+). This phase consists of corner-sharing SH6 octahedra with SH− ions at each A site (the centers of the S8 cubes). DFT calculations show that the perovskite (SH−)(H3S+) is thermodynamically more stable than the Im m structure of H3S, and suggest that the A site hydrogen atoms are most likely fluxional even at Tc . [ABSTRACT FROM AUTHOR]

For SiBr4 no crystal structures have been reported yet. In this work the crystal structures of SiBr4 were predicted by global lattice-energy minimizations using force-field methods. Over an energy range of 5 kJ mol-1 above the global minimum ten possible structures were found. Two of these structures were experimentally determined from X-ray synchrotron powder diffraction data: The low-temperature β phase crystallizes in P21/c, the high-temperature a phase in Pa3¯. Temperature- dependant X-ray powder diffraction shows that the phase transition occurs at 168 K. [ABSTRACT FROM AUTHOR]

First principles density functional theory calculations were carried out for the series of metal-rich compounds, LiPt2, LiPt, and Li2Pt, and elemental Pt for comparison, to probe the bonding picture that captures the essence of their electronic structures. Our analysis shows that the 5d-electron configuration of Pt in these compounds is close to (5d)10, and the electrons released from the Li atoms in the Li/Pt binary compounds are delocalized among the Pt0 atoms and Li+ ions through the interactions of the Pt 5d orbitals of each Pt with the Pt 6s/6p of neighboring Pt atoms and the Li 2s/2p orbitals of neighboring Li atoms. The electron counting schemes best representing the electronic structures of Pt metal, LiPt2, LiPt and Li2Pt are Pt0 (d10), Li+[Pt0 (d10)]2(e-), Li+[Pt0 (d10)](e-), and (Li+)2[Pt0 (d10)](2e-), respectively, and hence the Pt atoms of the Li/Pt binary compounds are predicted to exist as partially negative anions. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008 [ABSTRACT FROM AUTHOR]

The primary events of bacterial photosynthesis rely on the interplay of various specialized protein complexes organized in a supramolecular structure commonly termed the photosynthetic unit (PSU), which consists of the photochemical reaction center and of an associated antenna network. Employing single-molecule spectroscopic techniques we have been able to observe the excitation-energy transfer within a single PSU. From these findings we conclude that the building blocks of the PSU spontaneously form stable, functional aggregates in a non-membrane environment. [Copyright &y& Elsevier]