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Seventeen samples from paintings by the distinguished 19th century Portuguese painter, Henrique Pousao, were characterized by micro-X-ray diffractometry and infrared and Raman microspectroscopy. The main advantages and limitations of each technique for pigment identification are outlined, revealing the need for the use of complementary techniques. Pousao's palette is discussed.

Semi-insulating InP is implanted with MeV P, As, Ga and In ions, and the resulting evolution of structural properties with increased annealing temperature is analyzed using double crystal x-ray diffractometry and cross sectional transmission electron microscopy. The studies show that the amount and type of damage caused by implantation does not scale with implant ion atomic mass.

In this study, we report the use of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FT-IR) for the identification and quantitation of two polymorphs of Aprepitant, a substance P antagonist for chemotherapy-induced emesis. Mixtures of the polymorph pair were prepared by weight and ATR-FT-IR spectra of the powdered samples were obtained over the wavelength range of 700-1500 [cm.sup.-1]. Significant spectral differences between the two polymorphs at 1140 [cm.sup.-1] show that ATR-FT-IR can provide definitive identification of the polymorphs. To investigate the feasibility of ATR-FT-IR for quantitation of polymorphic forms of Aprepitant, a calibration plot was constructed with known mixtures of the two polymorphs by plotting the peak ratio of the second derivative of absorbance spectra against the weight percent of form II in the polymorphic mixture. Using this novel approach, 3 wt % of one crystal form could be detected in mixtures of the two polymorphs. The accuracy of ATR-FT-IR in determining polymorph purity of the drug substance was tested by comparing the results with those obtained by X-ray powder diffractometry (XRPD). Indeed, polymorphic purity results obtained by ATR-FT-IR were found to be in good agreement with the predictions made by XRPD and compared favorably with actual values in the known mixtures. The present study clearly demonstrates the potential of ATR-FT-IR as a quick, easy, and inexpensive alternative to XRPD for the determination of polymorphic identity and purity of solid drug substances. The technique is ideally suited for polymorph analysis, because it is precise, accurate, and requires minimal sample preparation.

The development of the electrical properties of composites as a function of the degree of mixedness of a conductive filler distributed into an insulating polymer is investigated. A wide-angle X-ray diffraction (WAXD)-based quantitative phase analysis method was used to characterize the variations of the concentrations of the insulating binder and the conductive particles around their mean values as a function of mixing time in an intensive batch mixer. Increasing the time and hence, the specific energy input, during the mixing process results in a more homogeneous spatial distribution of the conductive filler in the polymeric matrix, which in turn results in a decrease of the volume conductivity of the composite. The decreasing conductivity of the composite is attributed to the better coating and hence the isolation of the conductive particles from each other, thus hindering the formation of a conductive network 'percolation.' Overall, these results suggest that the control of the electrical properties of con ductive composites could benefit from a good understanding and adequate control of the dynamics of the mixing process and the resulting degree of mixedness of the conductive particles in the polymer matrix., INTRODUCTION AND BACKGROUND OF THE STUDY Electrically conductive nonmetallic materials are used in various applications including electromagnetic interference (EMI) shielding, adhesives, devices and sensors (1-6). Doping of the polymer, vacuum [...]

The crystal structure of katoite hydrogarnet has been refined at 0.0001, 2.15, 4.21, 5.09, 6.00, 7.09, and 7.78 GPa from single-crystal X-ray diffraction data using a 4:1 methanol:ethanol mixture as pressure medium in a Merrill-Bassett diamond-anvil cell. Below ~5 GPa, the katoite structure has Ia3d symmetry and compresses by bond shortening rather than bond bending, in agreement with recent quantum mechanical calculations. An unconstrained third-order Birch-Murnaghan fit to the unit-cell volumes and pressures for Ia3d symmetry gave the following equation of state parameters: [V.sub.o] = 1987.6(1) [A.sup.3], [K.sub.o] = 58(I) GPa and K' = 4.0(7). Above this pressure, the structure undergoes a phase transition to space group I[bar]43d, a non-centric subgroup of Ia3d. In the I[bar]43d structure, there are two non-equivalent ([O.sub.4][H.sub.4]) groups. Both the Ca and Al atoms are displaced along a relative to their positions in Ia3d. It is proposed that compression of the short H-H distance between ([O.sub.4][H.sub.4]) groups destabilizes the structure and may initiate the observed phase transition. Corroboration of this model will require accurate information on the hydrogen atom positions at pressures above 5 GPa.

The isothermal equation of state (EoS) of phase A, [Mg.sup.7][Si.sub.2][O.sub.8][(OH).sub.6], has been determined using high-pressure single-crystal X-ray diffraction. A third-order Birch-Murnaghan EoS fit to pressure-volume data collected from room pressure and temperature to 7.6 GPa results in [V.sub.0] = 512.56(3) [[Angstrom].sup.3], [K.sub.0] = 97.5(4) GPa, and K' = 5.97(14). Compression of the hexagonal (P[6.sub.3]) structure is anisotropic with the c axis, which is perpendicular to the distorted close-packed planes of anions, approximately 23% less compressible than the a axis: [K.sub.a] = 90.1(5) GPa with [K'.sub.a] = 5.4(2) and [K.sub.c] = 116.8(9) GPa with [K'.sub.c] = 7.5(3). The bulk modulus of phase A is intermediate between those of brucite (Br) and forsterite (Fo) and less than those of hydroxylclinohumite and hydroxylchondrodite, in a manner that is entirely consistent with its water content and density in relation to the Fo-Br series of minerals.

Research has been conducted on the Escherichia coli branched-chain amino acid aminotransferase. The three-dimensional structures of the amino acid aminotransferase's forms have been determined via X-ray diffractional method.

Research is presented concerning the use of photoluminescence measurements at low temperatures to determine the optical emission characteristics of high- and low-arsenic content In1-xGaxAsyP1-y alloys.

Research describes the synthesis and characterization of ternary and quaternary R-phase single-crystal structures containing lithium-zinc-aluminum and lithium-magnesium-aluminum systems. Electronic structural data are used in quantifying the site potentials of the elements based on Mulliken population analysis method.

Analyses of hexasodium diphosphopentamolybdate hydrate using a combination of multiple-quantum magic-angle spinning nuclear magnetic resonace and magic-angle spinning NMR techniques and X-ray powder diffraction reveal that the compound is triclinic, possesses water molecules and two phosphorous sites, and six nonequivalent sodium sites.

Research demonstrates structural similarities between the solid and nonaqualanthanum(III) trifluoromethanesulfonate and lanthanum(III) perchlorate solution as revealed bt EXAFS and large-angle X-ray scattering techniques. Data indicate that the La-O bond distances are 2.52(2) and 2.65 (3) Angstroms to the water molecules in the prism and capping confugurations, respectively.

Research has been conducted on linear ferrocenyl phosphine gold(I) and silver(I) complexes. The use of X-ray diffraction in determining the crystal structure of the complexes is discussed.

Research has been conducted on sodium dicyanamide NaC (sub)2 N (sub)3. The use of temperature-dependent X-ray powder diffractometry and thermal analysis is discussed.

Single crystals of yeast RNA polymerase II without Tpb4 and Tpb7 have been grown for structural analysis and to test some ideas about the molecule. The result was structure determination to better than 6.0-angstrom resolution. Appropriate treatment os S-ray diffraction from an unoriented 18-heavy atom cluster derivative have significant phase information to 5-angstrom resolution. Some structure-function relationships which underlie the transcription mechanism have been suggested.

The in-plane and out-of-plane structure of phospholipid monolayers were determined at the air-water interface as a function of hydrophilic lipid headgroup size. Synchrotron grazing-incidence X-ray diffraction and reflectivity were employed. Di-stearoyl-phosphatidyl-ethanolamine (DSPE) lipid monolayers were systematically modified by chemically grafting hydrophilic poly(ethylene glycol) chains to the lipid headgroups. The increased packing stresses from these bulky polymer headgroups distort the unit cell and the in-plane packing modes of the monolayers, leading to large out-of-plane changes and staggering of the lipid molecules.

Polymorphism is defined as the ability of a compound to adopt two or more conformations and/or arrangements in its crystalline state. Polymorphism and pseudopolymorphism (i.e., a change in solvation state) are important because the different crystal forms of a compound can have different physical properties, such as density, melting point, and solubility. Powder X-ray diffraction is currently the most common method for determining the existence of polymorphism in crystalline organic compounds. Solid-state 13C NMR spectroscopy has emerged as another powerful analytical technique for determining polymorphism. Both solid-state 13C NMR spectroscopy and powder X-ray diffraction have been used to analyze mixtures of the solid forms of neotame. Neotame, N-(3,3-dimethylbutyl)-L-aspartyl-L-phenylalanine methyl ester, is a new high-potency sweetener that exists in multiple solid forms. The most stable form of neotame under ambient conditions in the presence of moisture is a monohydrate. Altering the crystallization and drying conditions can generate mixtures of solid forms of neotame. A systematic study has been performed to observe the conversion under vacuum of the monohydrate to a mixture of forms and then reconversion to the monohydrate upon exposure to moisture under ambient conditions. No significant changes were observed in the powder X-ray diffraction patterns during part of the reconversion process, suggesting that no change in form had occurred. The solid-state 13C NMR spectra, however, indicated the presence of many forms of neotame during the reconversion. One possible reason that solid-state 13C NMR spectroscopy detected the changes in forms and powder X-ray diffraction did not is that the conformation of the neotame molecules changes between forms but the unit cell parameters do not change significantly.

Strain in patterned Al-Cu interconnect lines was measured with the x-ray microdiffraction method with about 1 micron spatial resolution. Measurements were made before and after the line sample was stressed for electromigration. Findings indicated an increase in inter- and intra-grain strain variation after the testing. Differences in strain behavior of grains with (111) and (200) crystallographic plates parallel to the substrate surface were seen. A position dependent variation of strain after the testing was measured while no such dependence was observed before the testing.

The composition and strain of pseudomorphic epitaxial layers were measured by high-resolution x-ray diffraction. Rocking curves or reciprocal space maps were measured from several reflections from sets of lattice planes, and their peak positions combined to yield the physical parameters of interest. Findings showed that the peak positions are best evaluated as the centers of gravity of the peaks. These data were then examined using least-squares multiple linear regression.

Research was conducted to examine the synthesis of phosphoranylidene carbenoids Mes*-P(=E)=C(X)Li(THF)3 (E = NMes*, C(SiMe3)2; X = Br, Cl, F) and to characterize their molecular structures using low-temperature X-ray diffractometry and multinuclear NMR studies. Results confirm the presence of moomeric molecules with THF-solvated metal atoms in both solution and solid state. NMR studies demonstrate that the dynamic exchange between the two components in solution can be directly monitored in 2D 6Li, 31P shift correlations.

A study using elemental, crystallographic structural and X-ray diffraction analyses was conducted to determine the structural and magnetic properties of trigonal bipyramid iron nitrosyl complexes. Results indicate that these iron nitrosyl complexes have almost similar molecular structures. The differences of their Fe-N-O angles have been assessed to range from 178.2(5) degrees in [Fe1iPr(NO)]- to 160.3(2) degrees in [Fe1dmp(NO)]-.

A study was conducted to characterize the structure of a mixed electron-proton conductor with specific capacitance called hydrous ruthenium oxide. Analysis of data gathered from thermogravimetric analysis, X-ray diffraction and X-ray absorption spectroscopy revealed that the local structures of the hydrous ruthenium oxides affect their electrochemical properties, particularly those that allow them to store energy.

One effective technique to characterize yttrium barium copper oxide bulk materials, thin film and single crystals is the microwave surface resistance measurements of high temperature superconductors. The method is done by adding mercury oxide to YBCO system. Studies that employed powder X-ray diffraction confirmed that pure orthorhombic 123 phase is formed without any indication of Hg or known Hg compounds.

Ag-doped YBa2Cu3O7-x (YBCO) thin films which are pulsed laser deposited in diameter sapphire wafers are regularly used in developing microwave filters for future communication systems. Critical current densities of 4 MA/cm2 at at 77 K and homogeneous maps of microwave surface resistance of about 45 momega at 145 GHz and 77 K are manifested in the reproducibly deposited YBCO:Ag films of about 250 nm thickness.

The strength of the adhesive properties of high temperature insulation materials on silver tapes was evaluated using a mini tensile testing machine. Scanning Electron Microscope, Energy Dispersive Spectroscopy and X-ray diffraction were used to determine the microstructures of coatings and their interfaces. Findings show that Y2O3, MgO and CeO2 doped ZrO2 demonstrated the best adhesive properties.

Various sizes of Al203 particles were added to Bi-2212 and conventional partial-melt processing methods were implemented to produce bulk material. The specimens were investigated through X-ray diffraction, transmission electron microscopy, scanning electron microscopy and through measurement of their superconducting properties. Slight decreases in the Tc and melting point of the Bi2Sr2CaCu2Ox and large expansions in magnetic-hysteresis were found after the additions.

An analysis on how the chemical reaction during partial melting and solidification is affected by the per-annealing and intermediate rolling (PAIR) process. The thermal analysis found no remarkable difference in the partial melting behavior between PAIR processed and control samples. However, results of the analyses using high temperature X-ray diffraction and scanning electron microscopes suggest that the (CaSr)CuO2 crystals did not grow in the samples processed by the PAIR technique.

Two pulse laser ablation-fabricated artificial superlattices were studied to determine the correlation between structural disorder and transport properties of superlattices. Using reflection high energy electron diffraction and X-ray diffraction analyses, it was found that the 10% of doping cannot bring too much disorder to the structure and resistivity of the superlattices, nor can it induce metal insulator transition.

Large area pulsed lased deposition (PLD) was used to grow homogenous YBa2Cu3O(sub 7-x) (YBCO) thin films and buffer layers on r-plane sapphire, MgO, LaAlO3 and on yttria stabilized ZrO2 substrates. Structural and electrical properties of these fabricated thin films were analyzed using X-ray diffraction and Rutherford Backscattering Spectroscopy/Channeling. Results show the homogeneity and reproducibility of the deposition process through PLD. Findings confirm the potential of the PLD method in fabricating large area thin films of complex oxide systems.

A study was conducted to examine the physical and structural properties of YBa2Cu3O(sub 7-delta) (YBCO) thin films, which have been deposited on two sides of a 2' lathanium aluminate (LaAlO3) substrate. The composition of the fabricated YBCO thin films was analyzed using Rutherford Backscattering spectrometry, electron microscopy and ion channeling, electrical resistivity and x-ray diffraction experiments. Results show that both side deposits have grown similar films. These fabricated films were found to be useful in making passive microwave devices.

A study was conducted to determine the effects of MgO particle addition to the flux pinning characteristics of the Bi-2212 superconducting bulk. Using X-ray diffraction analysis, electron probe microanalysis and SQUID magnetometer, it was found that the MgO particle addition enhances the flux pinning characteristics of Bi-2212 bulk. Hence, MgO particles act as effective pinning centers for processed Bi-2212 bulk.

Pulsed laser scanning was used to grow high-quality, high-temperature superconducting yttrium barium copper oxides (YBBCO) thin films with large area on phi 36 mm diameter LaAlO3 and phi 42 mm diameter Y-ZrO2 single crystal substrates. Using X-ray diffraction analysis, it was found that the fabricated YBCO thin films are completely c-axis oriented and have critical temperatures of 90 K both at the center and edge.

A new approach for making yttrium barium copper oxide (YBCO) coated tape conductors that produce biaxially texture textured thick films without the need for textured substrates is presented. The proposed method, which involves the use of a dynamic magnetic grain alignment technique, enhances the transport current critical density of the biaxially textured YBCO as compared to the identically prepared untextured or uniaxially textured samples.

A study was conducted to examine film growth of YBCO films with a high-quality in-plane texture deposited on different Ni, yttria-stabilized Zirkonia (YSZ) and Stainless Steel (SS) substrates. Using X-ray and TEM analyses, it was found that a difference in average temperature expansion coefficients of the substrate and YBCO films causes strains of -0.2% in the case of YSZ ceramic, and of -(0.3-0.4)% for Ni and Ss substrates.

The biaxial alignment of textured, Y2O3 stabilized ZrO2 (YSZ) buffer layers and large-area YBCO films on polycrystalline substrates was examined through X-ray diffraction. Findings show that the in-plane alignment of the YSZ buffer layer is at 14 to 18 degrees while YBCO exhibits a better alignment of seven to nine degrees. It also was noted that the difference of the alignment of the YSZ and YBCO is proportional to the alignment of the YSZ buffer layer.

YBa2Cu3O(sub 7-y) thin films were grown on (100)(001) cube textured Ag tape by hot-wall type organic chemical vapor deposition (MOCVD). Using x-ray diffraction, x-ray pole figure measurements and scanning electron microscopy, it was observed that the created films are highly c axis oriented and have smooth surfaces. It was also noted that the in-plane alignment of the films was not pure four-fold symmetric.

The capability of high-resolution x-ray diffraction, as a nondestructive technique, to provide data on atomic diffusion was studied. The study focused on the examination of Ti-diffused waveguide layers of LiNbO3 crystals for optoelectronic applications. Depth-resolved profiles of the interplanar spacing obtained from x-ray diffraction data were contrasted with the Ti-concentration profiles obtained by secondary ion mass spectrometry. Findings showed that both results can be employed for obtaining the Ti-diffusion coefficients in LiNbO3.

The potential energy surface for a catalyzed reaction has the fundamental parameters that determine the energy states in which the populations of reactants, intermediates and products are to be found. The goal of a study of a catalyzed conversion is finding a complete mechanism. Powerful X-ray diffraction techniques make it possible to take apart many substrate-catalyst structures. Enzyme-catalyzed reactions are discussed and multidimensional graphic models are used.

A study was conducted to analyze the correlation of atomic motions in crystals. The experiments were carried out in flat plate, transmission geometry for InAs and reflection geometry for nickel. It was shown that the motion of atoms and bonding with crystals can be determined by examining the peak width of the atomic pair distribution function. In addition, the Debye temperature was obtained that was in excellent agreement with literature values.

The three-dimensional structure of E. coli phosphoenolpyruvate carboxylase (PEPC) complexed with allosteric inhibitor L-aspartate is determined by x-ray diffraction at 2.8 angstrom resolution. The tetrameric structure of PEPC is described as dimer of dimers with a total molecular symmetry of D2. The PEPC monomer has an alpha-/beta-barrel motif with eight beta-strands surrounded by many helices. The C-terminal side of the beta-barrel is the assigned active site because the catalytically essential residues are found there.

The vertical variation of in-plane strain induced by an In0.1Ga0.9As single quantum well fixed in a free-standing wire structure on GaAs is analyzed using depth resolved x-ray grazing incidence diffraction. The basis of the theoretical investigation is the distorted wave Born approximation for grazing incidence geometry. By fitting the complete set of experimental grating truncation rods simultaneously, the structural parameters of the surface nanostructure were identified. The results are discussed.

Codeposited Ta and Ti on Si (111) and (100) substrates were analyzed at 1023, 1123 and 1223 using x-ray diffraction and sheet resistance measurements. To obtain (Ti,Ta)Si2 solid solution, high temperatures were required. The rate of solution formation relied on the substrate Si orientation and developed at a faster rate on Si (111). Multisilicide phases of the respective metals were obtained at lower temperatures. The results indicate that (Ti,Ta)Si2 solid solution is formed at high temperatures.

The phosphavinylidene carbenoid DME-solvate (Z)-Mes*-P=C(Cl){Li(DME)2} or the corresponding THF-solvate was distinguished by nuclear magnetic resonance spectroscopy and single-crystal X-ray diffractometry. Carbenoids were believed to be possible building blocks in organic chemistry and exhibit unique bonding capacity. It was observed that the carbenoid complex was a closely bound ion pair with its carbenic core acting mainly as a cryptocarbanion.

The crystal structure of a high-pressure [Fe.sub.3][O.sub.4] phase was determined by in situ X-ray diffraction measurements at high pressure and temperature, using an imaging plate detector and monochromatic synchrotron X-radiation. The high-pressure phase has the Pbcm space group (Ca[Mn.sub.2][O.sub.4]-type structure) with cell parameters a = 2.7992(3) [Angstrom], b = 9.4097(15) [Angstrom], and c = 9.4832(9) [Angstrom] at 23.96 GPa and 823 K. [Fe.sup.3+] occupies an octahedral site and [Fe.sup.2+] is in an eightfold-coordinated site described as a bicapped trigonal prism. The high-pressure Ca[Mn.sub.2][O.sub.4]-type [Fe.sub.3][O.sub.4] phase is about 6.5% more dense than the spinel form at 24 GPa.

A study was conducted to examine two spinel solid solution series by x-ray diffractometry and Mossbauer spectroscopy. Polycrystalline samples were prepared by solid state reactions using Fe2O3, NiO, CuO, and Al2O3 as starting materials. The fraction of iron ions were then obtained using the areas of Mossbauer effect subspectra. Results indicated the presence of cubic spinel phase supporting no additional lines that correlate with other phases.

A study was conducted to analyze the high-pressure response of the cell parameters of calcite, CaCO3. Single crystal X-ray diffraction was utilized to carry out the analysis. Data on the anisotropy of compression in calcite was determined. The unit cell parameters were refined from 0 to 1.435 GPa. Results indicated similarities between the pressure response of rhombohedral calcite and rhombohedral carbonates.

The stress-induced martensite transformation in TiNi at room temperature was analyzed in situ using synchrotron X-ray diffraction method. Martensic transformation in TiNi changes from a high-temperature B2 structure to a low-temperature monoclinic B19' phase. The results show that in the alloys with termperature-induced martensite in the beginning condition, a nonperiodic fluctuation of intensity of the X-ray reflexes appeared because of anomalous transformation.

A study was conducted to analyze the underpotential deposition of copper on Au(111) during the presence of bromide anions using electrochemical methods, crystal truncation rod measurements and in-situ grazing incidence x-ray diffraction. The x-ray reflections were correlated to the hexagonal coordinations of the Au(111) substrate. Specular crystal truncation red measurements were then performed across the Brag diffraction points.

Titanium nitride films were deposited by the methods of ion beam enhanced deposition (IBED), plasma chemical vapor deposition (PCVD) and ion plating (IP). X-ray diffraction analysis was employed to determine the internal stress state of TiN film and 52100 steel substrate at both sides of the interface. The effect of stress state on their bonding strength and tribological behavior was analyzed systematically, their wear and failure mechanisms were discussed in detail as well.