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Spherical silica-based mesoporous materials encapsulating magnetic nanoparticles have been synthesized following an aerosol-assisted route. The influence of nonionic surfactant P123 concentration in the structural and textural parameters has been investigated. Moreover, the effect of adding different amounts of magnetic nanoparticles to the precursor solution has been studied attending to structural, textural, and magnetic properties. The ability of these materials to achieve stability in aqueous solution at physiological pH, and their potential to be magnetically guided, have been evaluated. The microspheres adsorption and release performance have been tested by using ibuprofen as a model drug.

Three-dimensional networks with periodicity of several nanometres consisting of platinum crystallites have been examined by a combination of transmission electron microscopy, electron diffraction and high-angle annular dark-field scanning transmission electron microscopy. It has been clarified that the average three-dimensional structure of the networks deviates slightly from that of the mould, a silica mesoporous material. The existence of local distortion, misorientation of constituent platinum crystals and a defect structure of the networks have been found. The effectiveness and the importance of three-dimensional electron microscopy observations of nanomaterials with complicated configurations have been proved.

Two imidazolium templated aluminophosphate layers [N2C3H5]2 [Al3P4O16H] (1) and [N2C3H5] [AlP2O8H2(OH2)2] (2) have been synthesized under solvothermal conditions at 160°C. The effects of P/Al ratio the amount of organic amine and the type of solvent on the products are investigated. Their structures are characterized by single-crystal X-ray diffraction (XRD) powder XRD 27Al DOR NMR 31P MAS NMR and thermal analyses. Both compounds exhibit unusual structure architectures which are different from previously reported [Al3P4O16]3- and [AlP2O8]3- families. Compound 1 crystallizes in the triclinic space group of P1 (No. 2) with a=8.940(2), b=9.360(2), c=11.721(2) A, α=97.10(2), β=95.10(2), γ=91.91(2)°, V=968.4(3) A3 and Z=2. The structure contains a new macroanionic inorganic sheet characterized by a series of double six-membered ring (D6R) in which Al moieties (including AlO4 and AlO5) and P moieties [including PO4, PO3(=O) and PO2(=O) (OH)] are corner-shared through oxgens in an alternative manner. Compound 2 crystallizes in the monoclinic space group of C2/c (No. 15) with a=21.854(4), b=7.188(2), c=6.990(2) A, β=103.77(2)°, V=1063.5(5) A3 and Z=4. The structure is based on a new two-dimensionally connected inorganic network containing eight-membered rings in which AlO4(OH2)2 and PO2(OH)(=O) units are connected alternatively.

High-resolution electron microscopy (HREM) images of silicalite (ZSM-5) along [010] were taken with a 400-kV EM with a resolution of 1.6 A. The images contain a dark contrast in the centers of the main channels, where there are no atoms. This contrast is an artifact and is not appreciable in the HREM images which have been published so far. That this problem can be overcome by choosing the proper experimental conditions was confirmed by both computer-simulated and experimental HREM images. Computer image processing is also applicable to this kind of problem.

The authors describe a motion planning system for sliding operations with a parallel two-fingered gripper used to escape from a situation where an object cannot be grasped. First they describe the problems of escaping from a situation where an object cannot be grasped and the actions to solve them. Then they propose a new method for planning manipulator motions for these actions using sliding operations based on geometrical information about the environments. The results of the method and its validity are shown.

Publisher Summary This chapter discusses the template synthesis of ordered mesoporous carbon (OMC) molecular sieves. OMC of various structures, designated as CMK-1∼5, have been synthesized by the carbonization of sucrose, furfuryl alcohol, or other carbon sources inside silica or aluminosilicate mesopores that are interconnected into three-dimensional networks, such as in MCM-48, SBA-1, and SBA-15. The mesoporous carbon molecular sieves, obtained after template removal, show transmission electron microscopy (TEM) images and X-ray diffraction (XRD) patterns characteristic of the ordered arrangement of uniform mesopores. The OMC, which are opening up a new area of the nanoporous materials, exhibit high Brunauer–Emmett–Telle (BET) specific surface areas, excellent thermal stability in inert atmospheres, and strong resistance to attack by acids and bases.

Publisher Summary This chapter discusses the synthesis of offretite single crystals using pyrocatechol as complex agent. Compared with other methods, zeolite offretite prepared in this system has much larger size and better morphology. The influence of pyrocatechol has been studied, and the X-ray diffraction (XRD) patterns and the scanning electron microscopy (SEM) photographs of offretite single crystals have been shown. The role of pyrocatechol has been characterized by 27 Al nuclear magnetic resonance (NMR) and 29 Si NMR, which shows that an aluminum–pyrocatechol complex is formed in the reaction gel.

Publisher Summary This chapter presents the light-emitting boron nitride (BN), silicon (Si), and silicon carbide nanopowder (SiC) nanoparticles encapsulated in molecular sieves. Nanoparticles of Si, BN, and SiC encapsulated in zeolites, such as ZSM-5, L, APO-5, and MCM-41, have been successfully prepared, and strong visible photoluminescence (PL) have been observed at room temperature. Analysis of the PL spectra allows proposing that the transformation from indirect-gap semiconductor materials to quasi-direct-gap ones by encapsulation in the channels of zeolites is the possible origins of the strong PL.

Publisher Summary This chapter discusses a three-dimensional open-framework nickel aluminophosphate [NiAlP 2 O 8 ][C 2 N 2 H 9 ]. Its structure is solved by charge-coupled device (CCD) single crystal X-ray diffractometer, with Monoclinic, space group P2 1 /c (No. 14), a=8.542(2) A, b=15.564(3) A, c=7.627(1) A, and β=110.60(1)°, V=949.1(3)A 3 , Z=4, assemblied by one-dimensional AlP 2 O 8 3- and one-dimensional [Ni-O-Ni] chains. It is characterized by powder X-ray diffraction, thermogravimetric/differential thermal analysis, element analysis, and magnetic measurement.

The distal-proximal representation of the finger and palm in the first somatosensory cortex was reexamined. Somatosensory evoked magnetic fields (SEFs) were measured with a 37-channel first-order axial gradiometer system. Sensory stimulus comprising a 20-ms vibration at a frequency of 200 Hz was delivered to five successive sites in 3-cm increments along the distal-proximal direction over the volar surface of the right index finger and palm. Using a single dipole model, the sources and the signal strengths of the main peak (M50) of the SEFs were estimated. All of the sources were located in the 3b area. There were no statistically significant differences between the locations of dipoles evoked by stimulation of different sites. The results support those of our previous study using a 122-channel whole-head planar gradiometer system that orderly distal-proximal representation of the hand, as described in monkeys, is blurred in the adult human somatosensory cortex.

PbI2 clusters confined in spaces of LTA zeolite are successfully prepared through vapour phase. An HREM image showed that the crystallinity of the zeolite was preserved after preparation and showed directly that the clusters were incorporated into the α-cages. Absorption spectra were measured by diffuse reflection method as a function of loading density of PbI2 molecules. Several absorption bands from different cluster sizes were observed and showed remarkable blue shift. At the maximum loading, extra reflections, which are forbidden for Fm3A of LTA, were observed in electron and X-ray diffraction patterns. The appearence of the extra reflections and the dependence of absorption curve on the loading density suggest that superlattice of clusters was produced. The characteristic feature of zeolites as containers to make an artificial superlattice of clusters is pointed out.

24 European Crystallographic Meeting, ECM24, Marrakech, 2007 Page s229 Acta Cryst. (2007). A63, s229 MS26 P06 Lattice Geometry Change of Nanothin Selenium Crystals with the Growth in Amorphous Films V.B. Malkov, A.V. Malkov, O.V. Malkov, V.G. Pushin, B.V. Shulgin Institute of High-Temperature Electrochemistry, Ural Branch RAS, "ROSNA" Scientific and Production Center, Institute of Metal Physics, Ural Branch RAS, Ural State Technical University. E-mail: mvb@ihte.uran.ru

Zeolite Y or X (FAU) has a very open framework structure with 13 Å diameter cages. Small metal clusters fit well in such cages. In catalytic research it is essential to localize the metal clusters; are they in the zeolite cavities or on the zeolite surface? In this study we will describe a method, using high resolution transmission electron microscopy (HRTEM) imaging of ultrathin sections, that give evidence that platinum is located within the zeolite. It will be shown that clusters preferably aggregate in the larger cages of the frequently occurring {111}-twin planes (TP). Zeolite NaY (Si/Al=2.8) crystals were ion exchanged with Pt(NH3)4 Cl2 according to standard literature procedures. After ion exchange the specimen was oxidized in O2 at 383 K for three hours and finally reduced in H2 at 298 K for two hours.The zeolite crystals were embedded in epoxy resin (Spurr) for preparation of ultrathin sections. The composition of the resin was 15.0 g vinylcyclohexene dioxide (ERL 4206), 6.0 g polypropylene glycol diglycidyl ether (DER 736), 39.0 g nonenyl succinic anhydride (NSA), and 0.3 g dimethylamino ethanol (S-l).

High-resolution structure images of the 23-5 and 24 at.% Mn alloys annealed at 573 K were studied by 1 MV electron microscopy. It was shown that the 24 at.,% Mn alloy consists of two-dimensional antiphase structure (2d-APS) of Au3Mn with the boundaries parallel to the (100) and (010) planes. The average domain sizes were measured as M 1 = 1.04 and M 2 = 2.41, and an orthorhombic structure model with Mt=l and M2=2.5 was proposed for the ideal structure of the 2d-Au3Mn. From the 23.5 at.°,o Mn alloy, the structures corresponding to the intermediate state between the 2d-Au3Mn and the 2d-APS(I), which consists of lozenge- and parallelogram-shaped domains and exists in the alloys with 21--23 at.°o Mn, were observed. It was concluded that the statistical order of appearance of the stable ordered phases with increasing Mn content in the composition range of 20-24 at.to Mn is Au4Mn~Au,2Mno~Au 3~ Mn,~---, 2d-APS(I)~2d-AuaMn {so-called Watanabe structure).

The dependence of high-resolution electron microscope (HREM) images on the diffracted beams passing through the objective aperture is employed to derive the conditions necessary to observe particular structural features in the images. Using Ag-Y as an example, we show the advantage of “tuning” the electron microscope (EM) at a resolution dependent on the nature of the structural information sought by the experimenter and that, in some cases, lower rather than higher resolution may be preferable. Some failures in a recent HREM study of zeolites (Chan et al., 1987) are put in perspective.

A cryostat has been designed for an energy-dispersive X-ray diffractometer so that the specimen can be measured between 1.48 K and room temperature. Three powder samples can successively be measured at a fixed temperature by rotating the cryostat in steps of 120°. This design is very suitable particularly for detecting a slight change or difference, if any, in lattice constant among samples. A typical example is described of detecting the difference in lattice constant between 92Mo and 100Mo.

Zeolite L (idealized formula K 6 Na 3 Al 9 Si 27 O 72 . 21H 2 O) and synthetic mazzite (idealized formula Mg 2 (Ca, K 2 ) 3 Al 10 Si 26 O 72 . 28H 2 O ) otherwise known as zeolite omega and ZSM-4, are interesting mieroporous crystalline aluminosilicates of potential value as heterogeneous catalysts and catalyst supports. Their performance and future development for such purposes depend, however, upon their microstructural characteristics. We describe how these characteristics can be extracted from high resolution electron micrographs coupled with optical diffractometry and computer simulation. To improve the beam -stability of the zeolites they are first partly de- aluminated by using a process that is comparable with that employed industrially to enhance the thermal stability of zeolites in catalytic reactions. The correspondence between observed and calculated high-resolution images, both as a function of specimen thickness and extent of defocus of the objective lens, is good with synthetic mazzite, lending credence to the general correctness of the X -ray based structure, at least down to a resolution of 2.4 Å (1 Å = 10 -10 m = 0.1 nm). Several new types of structural faults have been discovered in the mazzite framework, and plausible models can be given for some, but not all, of these. In zeolite L, an unusual coincidence boundary, based on a mesh of √13x √13 times the hexagonal a dimension, has been discovered. The presence of such boundaries on (00.1) planes in a sample of catalyst would lead to severe diminution in diffusivity of reactant molecules to, or products from, active sites that are predominantly located, as for most zeolitic catalysts, on the interior surfaces of the crystal.

The intersecting-Kikuchi-line method, which is one of the electron diffraction methods of determining crystal structure factors, has been applied to Si at 1000 kV, with the object of improving the accuracy. It is shown that, with a favourable choice of line intersections, the accuracy is improved by at least a factor of two at 1000 kV compared to the case of 100 kV. From the intersections of the weak Kikuchi lines 1004, 9{\bar 1}3 and 0106 with the {\bar 1} {\bar 1} {\bar 1} line and from those of the 9{\bar 1}3, 8{\bar 2}2 and {\bar 1}95 lines with the {\bar 2}{\bar 2}{\bar 2} line, both the 111 and 222 structure factors are determined simultaneously, including their sign. The 220 structure factor, which cannot be determined by the critical-voltage method unless an accelerating voltage higher than 1000 kV is applied, is also determined from the intersection of the 95{\bar 3} line with the {\bar 2}{\bar 2}0 line. The results obtained agree with those determined by the X-ray Pendellosung method.

The concentration of vanadium atoms at interstitial tetrahedral sites in disordered VO0.82 and VO1.20 crystals has been determined by use of both the intersecting-Kikuchi-line method and the critical-voltage method. It is shown that not only the structure factor but also the temperature factor can be determined by combining the two methods. From the structure-factor values obtained, the existence of interstitial vanadium atoms is confirmed for the disordered VO1.20, supporting the assumption that the defect cluster typical of the ordered phase persists in the disordered state, whereas the interstitial concentration in the disordered VO0.82 is found to be nearly zero. For VO1.20 and VO0.82 the values of 1.21 ± 0.12 and 1.05 ± 0.10 A2 respectively at room temperature were obtained for the B factor which includes contributions from static atom displacements as well as the effect of thermal vibrations.

Production cross sections of composite particles at THETA/sub lab/ = 90/sup 0/ (the target-rapidity region) from 12-GeV proton reaction on nuclear targets have been measured. The particle spectra were analyzed with the coalescence model, and the radius of the production source was deduced to be R/sup rms//sub 0/ = 1.7 +- 0.5 fm. The radius is significantly smaller than the nuclear radii, and is independent on the target nuclear mass within uncertainties.

Electron micrographs of an f.c.c. Au-Mn alloy, of nominal composition mu79Mn21, recorded at 500 kV and better than 2 A point resolution, have demonstrated that it is possible to distinguish between different atomic columns of this material in thin specimen regions. These results have been confirmed by computer simulations which indicate that the conditions for imaging, namely the specimen thickness and the objective-lens defocus, are not critical. Some experimental images suggest that the occupation probability of separate columns in the beam direction might be determined although the sensitivity of the technique has not been examined. A small region of a novel superstructure, AulaMn4, has been observed.

Powdered samples of TiO0.82, TiO1.04 and TiO1.25 having the cubic rocksalt-type structure with high concentration of vacancies randomly distributed were held at combined conditions of high pressure, ranging from 1 GPa to 8 GPa, and high temperature, ranging from 973 K to 1173 K, and structural changes occurring were investigated by synchrotron radiation diffraction at the conditions and by conventional X-ray diffraction after the samples were brought back to ambient condition. Pressure has been shown to suppress formation of ordered arrangements of vacancies in all the samples and lead to precipitation of a hexagonal δ-Ti3O2 in TiO0.82 and TiO1.04 and precipitation of a corundum-type Ti2O3 in TiO1.25. Irreversible change in the lattice parameter of the remaining rocksalt-type structure has been observed which is due to partial annihilation of vacancies under pressure.

Differences in the lattice constants of Mo-100 and Mo-92 have been measured by x-ray diffraction, in order to search directly for the volume effect of isotopes in a superconductor. No significant difference in the lattice constanta(Mo-100)−a(Mo-92) could be detected at 290 K, while the differences −0.0014±0.0008 and −0.0029±0.0009 A were detected at 85.3 and 4.31 K, respectively. These values, and their temperature dependence, are considered to be theoretically reasonable. The exponent α in the isotope effect defined by Tc∝M-α is represented thermodynamically by α=−(∂ lnT c /∂ lnM)−(∂ lnT c /∂ lnV)(d lnV/d lnM). From the results, d lnV/d lnM is found to be −0.033±0.009 at 4.31 K. Then, the second term representing the isotopic volume effect is estimated to be about 0.09, with ∂ lnT c /∂ lnV≃2.81. The observed value of α is 0.33, so that the contribution of the second term, 0.09, is 27% of the value of α. It becomes quite clear that the isotopic volume effect in superconducting Mo should not be neglected.

A domain-like atomic arrangement is observed in the incommensurate 2d Au3+Zn with two-dimensional antiphase structure of Cu3Pd-type by high-resolution structure imaging method using 1000 kV electron microscope. Two types of domains with different structures occur by turns along (100) and (001). Inside the domains atomic arrangements are commensurate and antiphase periods are 6a and 5c, and the relative configuration of the domains produces incommensurate character.

An electron microscope investigation of slightly reduced rutile (TiOx x= 1·986, 1·94) suggests the existence of a new family of ordered phases, probably TinO 2n-1 (n=15,…∼36), derived from rutile by crystallographic shear on planes parallel to {132}. Still smaller degrees of reduction (x= 1·995) introduce disordered shear planes parallel to {132} and {101}. Some comments on the mechanism of reduction are also included.

The accelerating voltage Ec at which the second-order Kikuchi line vanishes has been measured for the 400 reflexions of A1, Ni and Cu and the 0004 reflexion of Ti. The X-ray atomic scattering factors fx for the first-order reflexion have been determined from the measured values of Ec and the results are compared with theoretical and X-ray experimental data.

According to the papers so far published about diffractometers with energy-dispersive detectors, the precision of a measured lattice spacing has been estimated to be about 0.05% at best. In the present paper, it is shown that a precision of about 0.01% is attainable without much difficulty by the use of a suitable Soller-slit system and a suitable scattering angle. This was demonstrated on an Al powder sample. It has been concluded that the limitation of precision is in the electronics rather than in the detector, when the necessary conditions are realised in the present improved system.

Superstructures existing in the composition range of 16–22 at .% Mg of the Au‐Mg system were investigated by electron diffraction. Besides the long‐period stacking variants, 4H and 10H, based on the DO23 structure and complex structure Au77Mg23. Two new structure were found to exist, i.e. a two‐dimensional antiphase structure of the 2d‐Cu3Pd type and a structure with unknown atomic arrangement. The existence ranges in composition and temperature of these structures were determined.

Dark-field images of two-dimensional antiphase domain structures with stepped boundaries have been simulated for imaging conditions corresponding to some current high resolution electron microscopes. The simulations reveal that the positions of the dots in the dark-field images do not give a true representation of atomic structure; thus, in contrast to the brightfield superstructure images, it is very misleading to say that bright dots in the dark-field image correspond exactly to the positions of the minority atoms.

Changes in the ordered structures of the Au-Mn system, existing at temperatures below 400°C, with composition have been studied in the range of 20–28 at.% Mn by high-resolution electron microscopy. The superstructures, Au4Mn, Au22Mn6, Au31Mn9 and 2d-APS(I), exist in the range of 20–23 at.% Mn. The Au22Mn6 and Au31Mn9 are the one-dimensional (ld) and two-dimensional (2d) antiphase structure (APS), respectively, based on the Au4Mn, and the 2d-APS(I) is based on the DO22 structure and consists of parallelogram and lozenge shaped domains. When Mn content increases, the Mn-Mn nearest-neighbour pairs are formed across the antiphase boundaries of the 2d-APS(I), and the structure changes to orthorhombic 2d-Au3Mn at about 24 at.% Mn. When Mn content increases further, the Mn-Mn pairs align in the direction and the structure transforms continuously to the monoclinic Au5Mn2.

The X-ray atomic scattering factors f ; X for the 110 reflection of V and Cr have been determined by high voltage electron diffraction, and the results are compared with theoretical values.

The λ ray Compton profiles along the three major axes have been measured on a chromium single crystal with a pure Ge solid-state detector. Anisotropy curves observed among these profiles have been compared with the relevant theoretical curves.

Compton profileswere measured on TiO 1.25 and TiO 0.82 with an SSD and γ-ray source. The results were compared with the profiles calculated from isolated ions and also with the scattering factor values obtained with the critical voltage effect.