Search

Crystallization by particle attachment (CPA) is a frequently occurring mechanism of colloidal crystallization that results in hierarchical morphologies.sup.1-4. CPA has been exploited to create nanomaterials with unusual properties.sup.4-6 and is implicated in the development of complex mineral textures.sup.1,7. Oriented attachment.sup.7,8--a form of CPA in which particles align along specific crystallographic directions--produces mesocrystals that diffract as single crystals do, although the constituent particles are still discernible.sup.2,9. The conventional view of CPA is that nucleation provides a supply of particles that aggregate via Brownian motion biased by attractive interparticle potentials.sup.1,9-12. However, mesocrystals often exhibit regular morphologies and uniform sizes. Although many crystal systems form mesocrystals.sup.1-9 and individual attachment events have been directly visualized.sup.10, how random attachment events lead to well defined, self-similar morphologies remains unknown, as does the role of surface-bound ligands, which are ubiquitous in nanoparticle systems.sup.3,9,11. Attempts to understand mesocrystal formation are further complicated in many systems by the presence of precursor nanoparticles with a phase distinct from that of the bulk.sup.1,13,14. Some studies propose that such particles convert before attachment.sup.15, whereas others attribute conversion to the attachment process itself.sup.16 and yet others conclude that transformation occurs after the mesocrystals exceed a characteristic size.sup.14,17. Here we investigate mesocrystal formation by iron oxides, which are important colloidal phases in natural environments.sup.18,19 and classic examples of systems forming ubiquitous precursor phases and undergoing CPA accompanied by phase transformations.sup.15,19-21. Combining in situ transmission electron microscopy (TEM) at 80 degrees Celsius with 'freeze-and-look' TEM, we tracked the formation of haematite (Hm) mesocrystals in the presence of oxalate (Ox), which is abundant in soils, where iron oxides are common. We find that isolated Hm particles rarely appear, but once formed, interfacial gradients at the Ox-covered surfaces drive Hm particles to nucleate repeatedly about two nanometres from the surfaces, to which they then attach, thereby generating mesocrystals. Comparison to natural and synthetic systems suggests that interface-driven pathways are widespread. Mesocrystal formation is investigated for haematite in the presence of oxalate, showing that chemical gradients at interfaces cause nucleation near surfaces rather than in the bulk, followed by particle attachment., Author(s): Guomin Zhu [sup.1] [sup.2] , Maria L. Sushko [sup.1] , John S. Loring [sup.1] , Benjamin A. Legg [sup.1] [sup.2] , Miao Song [sup.1] , Jennifer A. Soltis [sup.1] [...]

It is widely believed that [beta]-nucleating agent is beneficial for effectively toughening isotactic polypropylene (iPP). However, for the injection molding process, the shearing and thermo-mechanical conditions make the nucleation and crystallization process complicated. In this paper, the effects of injection rate on crystallization of [beta]-nucleated iPP were studied by scanning electron microscope (SEM), two-dimensional wide-angle X-ray diffraction and differential scanning calorimetry (DSC). It is observed that with increasing injection rate, the content of [beta]-crystals exhibits different tendencies in the skin, intermediate layers, and core zone. Specifically, for the intermediate layer, the [beta]-crystals content first increases with increasing injection rate to 85 cm [s.sup.-1], and begins to decrease afterward. By simulating the injection process, the most likely explanation for the [beta]-crystal change is the comparatively high shear rate and low shearing time that the melt experienced. Variations in [beta]-form content are mainly responsible for the mechanical properties of [beta]-nucleated iPP. The results of this study provide a valuable way to control the iPP toughness in the injection molding process., INTRODUCTION Isotactic polypropylene (iPP) is one of the most widely used thermoplastic materials [1]. However, low impact toughness has limited its extensive application, especially at low temperatures. To overcome the [...]

A review of nucleating agent (NA) types and their effect on crystallization in high-density polyethylene (HDPE) is presented. The focus is on methods to improve the physical properties of HDPE due to its widespread use in commercial applications and high volume use in typical industrial processes including extrusion, injection molding, and blow molding. The crystallization process in HDPE significantly affects its final optical, mechanical, and thermal properties. The addition of NAs affects the physical properties of HDPE by controlling the crystallization from the melt state. Specific NAs improve properties such as clarity, cycle time, and modulus. NAs are more widely developed for polypropylene (PP) than HDPE as its slower crystallization rate allows greater control in achieving property improvements. While certain NAs are effective in improving property characteristics in HDPE, greater control over the crystallization process would achieve further improvements in specific properties. Research has progressed in identifying effective NAs for HDPE, though the magnitude of the effects remains lower than those generally observed in PP. Inorganic and organic NAs are reviewed with an emphasis on the mechanisms by which they function. Fundamentals of polymer crystallization and modeling kinetics during both isothermal and nonisothermal studies provide the necessary framework for characterizing the effects of a NA in HDPE. Finally, the interactions between HDPE, NA, and industrial processing conditions as related to practical applications are discussed., INTRODUCTION In industrial applications, polymers are melted in processing steps such as extrusion and molding and the size, dimension, and distribution of crystalline domains, or crystallites developed upon cooling determine [...]

Viscoelasticity was applied to monitor the early stage of the crystallization process of poly(lactic acid). The evolution of the storage modulus in the process was divided into three stages with the help of optical microscopy. A simple model, combining the kinetics of embryo population and the Palierne Equation for suspension, was proposed to describe the evolution of the storage modulus along the process. The model was extremely successful in portraying the rheological behavior. Rate constants related to the nucleation and the formation and dissociation of the embryo, as well as the Avrami parameter, could therefore be determined by the rheological tool. Although linear viscoelasticity is frequency dependent, the rate constants were found to be essentially independent of the frequency applied. The Avrami parameter was found to have a threefold change over a frequency range of more than two orders of magnitude, which could be an important reference for the frequency selection when implementing the rheological tool in the investigation of polymer crystallization., INTRODUCTION The crystallization behavior of semicrystalline polymers is crucial in the final mechanical properties of the plastic products. Crystallization commonly occurs in industrial processing such as fiber spinning, die extrusion, [...]

Two semicrystalline poly(3-hydroxybutyrate) (PHB) and polylactic acid (PLLA) blends with and without poly (vinyl acetate) (PVAc) were prepared by dissolving different ratios in hot chloroform at 50 °C to obtain promising alternative biodegradable materials for eliminating plastic waste. The miscibility, crystallization, melting behavior and vibration modes of the prepared samples were characterized by differential scanning calorimetry (DSC), polarized optical microscopy (POM), Fourier transform infrared spectroscopy (FTIR), and wide angle X-ray diffraction (WAXD) techniques. DSC analysis showed that only one crystallization temperature for blends with PVAc (single homogeneous phase) and two crystallization temperatures for blends without PVAc (immiscible blends) were obtained. The POM results indicated that the morphological structures of B38I B551, and B83i samples consist of two types of spherulites (fibrils and banded) which created at different crystallization temperatures. The irrelevant interaction between PHB and PLLA structures was detected from FTIR spectra. The addition of PVAc caused an obvious decrease in the peak position of the carboxyl group C=0 from 1752 to 1724 cm'1 due to dipoledipole interactions. WAXD indicated that the lattice parameters are changed in blends with PVAc and unchanged without PVAc-Our results indicated that, the PVAc can be used as compatibilizer and improved the compatibility between PHB and PLLA. POLYM. ENG. SCI., 51:2191-2202, 2011. ©2011 Society of Plastics Engineers, INTRODUCTION The quantities of plastic waste are increasing in all places of the world as the production and consumption of plastic materials. Most of these plastic materials are produced from [...]

This study proposes an experimental method to quantify the molecular orientation of the crystalline phase of isotactic polypropylene from polarized Raman spectroscopy measurements. The method is based on the intensity sensitivity of two Raman scattering bands located at 973 (C-C stretching mode) and 998 c[m. sup -1] (C[H. sub 3] rocking mode) to laser light polarization. The first part of this article is devoted to the validation of the method by comparing Raman and Wide Angle X-ray Scattering (WAXS) results obtained on postmortem test samples uniaxially deformed at growing levels. Second, the method is applied to follow the molecular orientation in situ during a tensile test by combining a video-controlled test machine and a Raman spectrometer. Postmortem results show a quantitative agreement between Raman and WAXS measurements. In situ results mainly evidence the ability of the Raman method to characterize molecular orientation in real-time with less than 5 s time resolution. POLYM. ENG. SCI., 51:1607-1616, 2011. ©2011 Society of Plastics Engineers, DOI 10.1002/pen.21944 INTRODUCTION To gain a better understanding of the mechanical properties of solid polymers, it is fundamental to understand the mechanisms of deformation which take place at the microstructure [...]

The importance of nonclassical, multistage crystallization pathways is increasingly evident from theoretical studies on colloidal systems and experimental investigations of proteins and biomineral phases. Although theoretical predictions suggest that proteins follow these pathways as a result of fluctuations that create unstable dense-liquid states, microscopic studies indicate these states are long-lived. Using in situ atomic force microscopy to follow 2D assembly of S-layer proteins on supported lipid bilayers, we have obtained a molecular-scale picture of multistage protein crystallization that reveals the importance of conformational transformations in directing the pathway of assembly. We find that monomers with an extended conformation first form a mobile adsorbed phase, from which they condense into amorphous clusters. These clusters undergo a phase transition through S-layer folding into crystalline clusters composed of compact tetramers. Growth then proceeds by formation of new tetramers exclusively at cluster edges, implying tetramer formation is autocatalytic. Analysis of the growth kinetics leads to a quantitative model in which tetramer creation is rate limiting. However, the estimated barrier is much smaller than expected for folding of isolated S-layer proteins, suggesting an energetic rationale for this multistage pathway. in situ atomic force microscopy imaging | protein crystal growth | two-step crystallization | amorphous precursors | assembly kinetics doi/ 10.1073/pnas.1008280107

A centrifuge-based microfluidic system has been developed that enables automated high-throughput and low-volume protein crystallizations. In this system, protein solution was automatically and accurately metered and dispensed into nanoliter-sized multiple reaction chambars, and it was mixed with various types of precipitants using a combination of capillary effect and centrifugal force. It has the advantages of simple fabrication, easy operation, and extremely low waste. To demonstrate the feasibility of this system, we constructed a chip containing 24 units and used it to perform lysozyme and cyan fluorescent protein (CyPet) crystallization trials. The results demonstrate that high-quality crystals can be grown and harvested from such a nanoliter-volume microfluidic system. Compared to other microfluidic technologies for protein crystallization, this microfluidic system allows zero waste, simple structure and convenient operation, which suggests that our microfluidic disk can be applied not only to protein crystallization, but also to the miniaturization of various biochemical reactions requiring precise nanoscale control. 10.1021/ac902904m

The recognition that postcumulus processes significantly modify primary textures in layered mafic intrusions has thrown into question many early observations on which classical crystallization theories are based. Petrographic observations combined with quantitative textural analysis of samples from various stratigraphic levels of the Lilloise intrusion, East Greenland, demonstrate that postcumulus textural modification of cumulates, formed during the solidification of a closed system magma chamber, may be detected. Crystal size distribution (CSD) measurements of Lilloise cumulates and the resulting CSD profiles are compared to predicted theoretical closed system CSD profiles. Similarities between the measured CSD profiles and published predicted CSD profiles support Lilloise magma evolving in a closed system chamber and indicate that primary crystallization processes can be distinguished using quantitative textural techniques. Textural coarsening driven by syn-magmatic deformation is suggested to be the dominant postcumulus process affecting CSD plot morphology. CSD slope values and profiles (plot shapes) remain relatively constant for a given liquidus mineral (particularly olivine and clinopyroxene), so that the number of phases on the liquidus at any one time affects mineral modal abundances. As a result, CSDs generally exhibit overall smaller grainsizes and progressively lower nucleation densities at higher levels in the intrusion. Keywords: Lilloise, layered mafic intrusion, crystal size distribution, closed system, solidification. doi: 10.1017/S0016756809990689

We report the fabrication and optical properties of planar and channel wavegnides on z-cut near-stoichiometric LiNb[O.sub.3] crystal formed by 6.0MeV [O.sup.3+] implantation at a dose of 5 x [10.sup.14] ions/[cm.sup.2]. The properties of the planar wavegnide are characterized by use of prism coupling and the reflectivity calculation method. It is found that the effective refractive indices of the transverse magnetic modes increase but the transverse electric ones decrease when an appropriate heat annealing treatment is performed. We also find that only transverse magnetic polarized light could be guided in this waveguide effectively, although the dark mode could be detected in both the transverse electric and the transverse magnetic directions. OCIS codes: 230.7380, 240.5440.

Peace River is one of the few shocked members of the L-chondrites clan that contains both high-pressure polymorphs of olivine, ringwoodite and wadsleyite, in diverse textures and settings in fragments entrained in shock-melt veins. Among these settings are complete olivine porphyritic chondrules. We encountered few squeezed and flattened olivine porphyritic chondrules entrained in shock-melt veins of this meteorite with novel textures and composition. The former chemically unzoned ([Fa.sub.24-26]) olivine porphyritic crystals are heavily flattened and display a concentric intergrowth with Mg-rich wadsleyite of a very narrow compositional range ([Fa.sub.6]-[Fa.sub.10]) in the core. Wadsleyite core is surrounded by a Mg-poor and chemically stark zoned ringwoodite ([Fa.sub.28]-[Fa.sub.38]) belt. The wadsleyite-ringwoodite interface denotes a compositional gap of up to 32 mol % fayalite. A transmission electron microscopy study of focused ion beam slices in both regions indicates that the wadsleyite core and ringwoodite belt consist of granoblastic-like intergrowth of polygonal crystallites of both ringwoodite and wadsleyite, with wadsleyite crystallites dominating in the core and ringwoodite crystallites dominating in the belt. Texture and compositions of both high-pressure polymorphs are strongly suggestive of formation by a fractional crystallization of the olivine melt of a narrow composition ([Fa.sub.24-26]), starting with Mg-rich wadsleyite followed by the Mg-poor ringwoodite from a shock-induced melt of olivine composition ([Fa.sub.24-26]). Our findings could erase the possibility of the resulting unrealistic time scales of the high-pressure regime reported recently from other shocked L-6 chondrites. focused ion beam | transmission electron microscopy | shocked chondrite | high-pressure mineral

Abstract: Poly(L-lactide) ultrathin films of thicknesses between 10 and 80 nm were crystallized between 100 and 170 °C. Four different morphologies were obtained: single crystals, hedrites, dendrites, and spherulites. Dendrites [...]

Poly(phenylene sulfide)/ferrosoferric oxide composites (PPS/[Fe.sub.3][O.sub.4]) with various loading levels were prepared by melt compounding. The crystallization, thermal, and viscoelastic properties were characterized respectively by the DSC, DMA, TGA and parallel plate rheometer. The results reveal that the well-dispersed [Fe.sub.3][O.sub.4] particle restricts the segmental motion of polymer chain, leading to a remarkable increase of the glass transition temperature and thermal stability of the PPS due to the strong physical association and interactions between particles and matrix. The presence of the [Fe.sub.3][O.sub.4] particles, however, can not facilitate crystallization of PPS, because the particles only play the role of inert filler and have no heterogeneous nucleating effect. The crystallization kinetics, as a result, decreases with increasing particles loadings due to the increasing restriction of the chain mobility and high viscosity. In addition, the rheological percolated network of the [Fe.sub.3][O.sub.4] particles is very sensitive to the steady shear deformation, and also to the temperature. The network structure is easily broken by the steady shear flow due to the sharply reduced particle-particle interactions. However, the percolation threshold reduces with increase of temperature, because those interactions are temperature-dependent. POLYM. ENG. SCI., 48:966-975, 2008. © 2008 Society of Plastics Engineers, INTRODUCTION Poly(phenylene sulfide) (PPS) is a high-performance semicrystalline polymer that has been utilized in a variety of market segments such as electrical, electronic, automotive, appliance, industrial, and chemical sectors due [...]

Linear correlations of lnP vs. the thickness, t, of the TOT mica module and vs. the ditrigonal distortion, [alpha], have been established by analyzing a population of 43 natural phengites for which estimates of the crystallization pressure P independent of the Si content are available. Synthetic phengites are not included because they behave as a separate population. The equations for the resultant regression lines are InP = -0.35(3)[alpha] + 5.0(3) (R = 0.90, 26 observations) and lnP = -29(2)t + 293(22) (R = 0.90, 43 observations). These linear correlations are evidence of the links involving P, chemical composition, structural parameter c (i.e., t), and [alpha]. In turn, there is a linear correlation between t and [alpha]: t = 0.0110(9)[alpha] + 9.859(7) (R = 0.92, 26 observations). The linear correlations of lnP, t, and [alpha] vs. Si content have equations: InP = 4.2(4)Si - 12(I)(R = 0.86, 43 observations), t = 0.13(1)Si + 10.37(4) (R = 0.87, 43 observations), and [alpha] = -12.7(9)Si + 50(3) (R = 0.94, 26 observations). The observed dispersion of the data are mainly due to the uncertainty in the pressures estimated from mineral assemblages. The possibility of calculating P from only a measurement of neither overcomes this type of uncertainty nor pretends to be competitive with petrologic geobarometers, but is does open the possibility of estimating the crystallization pressure of nanoscale phengite relics (e.g., by transmission electron diffraction). Keywords: Phengites, crystallization pressure, pressure- structure correlation, ditrigonal distortion, mica module thickness

Using optical microscopy, we have studied the phase behavior of mixtures of 12- to 22-bp-long nanoDNA oligomers. The mixtures are chosen such that only a fraction of the sample is composed of mutually complementary sequences, and hence the solutions are effectively mixtures of single-stranded and double-stranded (duplex) oligomers. When the concentrations are large enough, such mixtures phase-separate via the nucleation of duplex-rich liquid crystalline domains from an isotropic background rich in single strands. We find that the phase separation is approximately complete, thus corresponding to a spontaneous purification of duplexes from the single-strand oligos. We interpret this behavior as the combined result of the energy gain from the end-to-end stacking of duplexes and of depletion-type attractive interactions favoring the segregation of the more rigid duplexes from the flexible single strands. This form of spontaneous partitioning of complementary nDNA offers a route to purification of short duplex oligomers and, if in the presence of ligation, could provide a mode of positive feedback for the preferential synthesis of longer complementary oligomers, a mechanism of possible relevance in prebiotic environments. condensation | nucleation | depletion | prebiotic | PEG

There are [approximately equal to]350 non-odorant G protein-coupled receptors (GPCRs) encoded by the human genome, many of which are predicted to be potential therapeutic targets, but there are only two structures available to represent the whole of the family. We hypothesized that improving the detergent stability of these receptors and simultaneously locking them into one preferred conformation will greatly improve the chances of crystallization. We developed a generic strategy for the isolation of detergent-solubilized thermo-stable mutants of a GPCR, the [beta]1-adrenergic receptor. The most stable mutant receptor, [beta]AR-m23, contained six point mutations that led to an apparent [T.sub.m] 21[degrees]C higher than the native protein, and, in the presence of bound antagonist, [beta]AR-m23 was as stable as bovine rhodopsin. In addition, [beta]AR-m23 was significantly more stable in a wide range of detergents ideal for crystallization and was preferentially in an antagonist conformation in the absence of ligand. G protein-coupled receptor | membrane protein | stabilization

The atomic structure of amorphous Bi4Ti3O12 (BiT) prepared by rapid quenching is studied and its crystallization process using high-energy X-ray diffraction is investigated. The structural relationship between the amorphous and the crystalline state by high-energy X-ray diffraction and atomic pair distribution function analyses is established.

Graphite, graphite-tantalum (Ta) and Ta growth environment to the sublimination epitaxy of aluminum nitride (AIN) is implemented, and morphological and cathodoluminescence emission properties of AIN crystals are studied. Three different types of crystallites form in the three different type of growth environment, which presumably manifests the relationship between crystallite-habit-type and impurities are presented.

Conjugate bases of phosphoric acid form adducts with the hexaazamacrocycle, [18]aneN6, the composition of which varies with the ph of crystallization. At higher ph, the addition of water aids in the formation of stable structures.

Combined solution chemistry crystallization and crystallographic data are combined to investigate the impact of molecular speciation on crystal nucleation in polymorphic systems. The conclusion states that solution speciation and the consequent interactions between charged species and developing crystal nuclei determine the structural outcome of the crystallization process.

The first direct transmission electron microscopic (TEM) observation is carried out on the continuous monocrystal-thick b-oriented pure silica zeolite MFI films produced by in situ crystallization. This TEM investigation provides direct unambiguous new evidence to support the homogeneous nucleation mechanism by which the films form through homogeneous nucleation and crystal growth in the bulk to form equal-sized disk-shape crystals followed by self-assembly of these crystals onto the substrate to produce a two-dimensional close-packed structure.

Fourier transform infrared (FTIR) spectroscopy technique is used to analyze the isothermal crystallization behavior of poly(L-lactide) (PLLA) at 150 degree Celsius from the melt. The two-dimensional (2D) correlation analysis of time-dependent IR spectra is used to elucidate the details about the intermolecular interaction of the CH3 and C=O groups and the conformational changes in the C-O-C backbone during melt crystallization process.

The process of preparing molecularly ordered layered silicate-surfactant mesophases from the stepwise phase transformation of surfactant-silicate composites is described. The resulted calcined molecularly ordered layered mesoporous silica exhibit structurally well-ordered domains with relatively high surface area and pore volume.

A study focused on the 2-shot sequential lateral solidification (SLS) process for crystallization of thin films for thin-film transistor (TFT) applications by investigating the effect of process parameter variation on the resulting microstructure, as well as on the performance of TFTs fabricated on the material is presented. The method helps to improve the mobility directionality ration between devices with majority carrier flow parallel and perpendicular to the lateral growth direction, respectively from 0.3 to over 0.7.

The influence of initial rotational energy on the adsorption of CO to the (0001) crystalline ice I(sub h) surface is predicted using molecular dynamics (MD) simulations. At low incidence energies (viz. 24.1 and 48.2 kJ mol(super -1), there is an approximately exponential decrease in the trapping probability with increased initial rotation.

The photocatalytic properties for water decomposition of RuO2-dispersed alkaline earth metal and lanthanum indates with an octahedrally coordinated In(super 3+) ion of d(super 10) configuration are studied. It was shown that the combination of well-crystallized CaIn2O4 with highly dispersed RuO2 particles led to high photocatalytic performance: Hydrogen and oxygen were stably produced at nearly the stoichiometric ratio under UV irradiation.

The pH and salt dependent self-association of hen egg-white lysozyme (HEWL) is studied extensively, mainly by scattering techniques. The findings of the study help to explain why HEWL tends to form amorphous precipitates in the presence of sulfate and why crystallization of HEWL is facilitated by sulfobetaine.

Neutron and X-ray crystal structures of p-chlorophenylformamide (ClC6H4NHCHO, 1) are determined after recrystallization from methanol and acetone solvents. All structures reveal that the formamide group is essentially coplanar with the chlorophenyl ring.

Pharmaceutical compounds are molecular solids that frequently exhibit polymorphism of crystal form. One high profile case of polymorphism was ritonavir, a peptidomimetic drug used to treat HIV-1 infection and introduced in 1996. In 1998, a lower energy, more stable polymorph (form II) appeared, causing slowed dissolution of the marketed dosage form and compromising the oral bioavailability of the drug. This event forced the removal of the oral capsule formulation from the market. We have carried out high-throughput crystallization experiments to comprehensively explore ritonavir form diversity. A total of five forms were found: both known forms and three previously unknown forms. The novel forms include a metastable polymorph, a hydrate phase, and a formamide solvate. The solvate was converted to form I via the hydrate phase by using a simple washing procedure, providing an unusual route to prepare the form I 'disappearing polymorph' [Dunitz, J. D. & Bernstein, J. (1995) Acc. Chem. Res. 28, 193-200]. Crystals of form I prepared by using this method retained the small needle morphology of the solvate and thus offer a potential strategy for particle size and morphology control.

The crystallization of the diluent occurs within the entangled polymer chains, which act as a confining frozen and hard tube involving an unfrozen solvent within. The calculation for two different cases of lightly cross-linked and un-cross-linked rubber mixtures explain the crystal sizes determined by X-ray and NMR measurements for some relevant concentrations.

Several solid-state NMR techniques are used in conjunction with powder X-ray diffraction (XRD) and FT-Raman spectroscopy to characterize the structures of the intermediate phases of AlPO4-11 molecular sieve synthesis. The evolution of the gel phases as a function of crystallization time was followed by (super 31)P and (super 27)Al magic angle spinning NMR to obtain information on the local environments of Al and P atoms and by powder-XRD to detect the long range ordering of the gel samples.

A study is conducted to develop the highly crystalline nanoprticles of NiO(sub x)/In(sub 0.9)Ni(sub 0.1)TaO(sub 4), with a wolframite-type structure, with the help of a solid-state reaction method. The TEM measurements indicate that nearly spherical nano NiO(sub x) particles with a size of about 15 nm are distributed on the surface of In(sub 0.9)Ni(sub 0.1)TaO(sub 4) with a quantum yield of about 0.66 percentage.

The two new mixed-valent triple perovskites, Ba3MRu2O9 (M=Li, Na), that were grown from reactive hydroxide fluxes are reported. They crystallize in the hexagonal space group P6(sub 3)/mmc, where Ru(V) and Ru(VI) are disordered on only one crystallographic site.

The crystal structures of cage complex 1b with neutral guest molecules are discussed. The solid structures obtained are found to be in good accordance with solution structures elucidated by NMR, showing that the encapsulation geometry in the solid-state remains unchanged even in solution.

Block copolymers self assemble in selective solvents and normally give spherical star like micelles in solvents selected for longer blocks. It is found that samples of poly(ferrocenylsilane-dimethyl siloxane) (PFS) with block ratios of 1:12 form nanotubes and when self-assembly takes place the PFS blocks add up and crystallize to form a shell with a cavity in the center of the tube.