DFT

In this paper the conformational behavior and thermodynamics of radical scavenging action of alizarin (A) and alizarin red S (ARS) were investigated at the M06-2X/6-311++G(d,p) and M06-2X/cc-pVTZ levels of theory in the gas phase and water solution. For this purpose all BDE (bond dissociation enthalpy), IP (ionization potential), PDE (proton dissociation enthalpy), PA (proton affinity), and ETE (electron transfer enthalpy) values were calculated, implying that all radicals, anions, and radical cations issued from A and ARS were examined. Since it turned out that all thermodynamic parameters for A and ARS are mutually comparable, one can assume that the two compounds are of similar antioxidative capacity, implying that the influence of the sulfonate group is insignificant. It was shown that the hydroxyl group in position 2 of A and ARS is the preferential site for heterolytic and homolytic cleavage in both phases, as the negative charge and spin density in the formed anions and radicals are delocalized over the B ring. In spite of the fact that the IP values of A and ARS are significantly lower in water, SET-PT is not a favored mechanism of both molecules in either environment. On the other hand, HAT is the predominant reaction pathway of A and ARS in gas, whereas SPLET is the preferential mechanism in water.

The reaction of gold with thiosaccharin ligand and additional phosphorous coligands is studied. Four new Au(I) complexes with thiosaccharinate as coordinating counteranion: [Au(tsac)(PPh 3)], [Au 2 (tsac) 2 (dppm)]ÁEtOH, Au 2 (tsac) 2 (dppe)ÁEtOH, and Au(tsac)(Htsac) 2 Á0.25 EtOH (tsac: thiosaccharinate, C 6 H 4 C(S)NSO 2 À , dppm: bis(diphenylphosphino)methane, dppe: bis(diphenylphosphino)ethane) were synthesized and characterized by means of spectroscopic techniques (IR, UV-Vis, and 1 H, 13 C and 13 P NMR). The crystal structure of two of them, [Au(tsac)(PPh 3)] and [Au 2 (tsac) 2 (dppm)]ÁEtOH, were solved applying single crystal X-ray diffraction and studied using the density functional theory (DFT) formalism. In the latter, the aurophilic interaction between the two gold centers was analyzed and theoretically confirmed.

The adsorption properties of pyridine on H-ZSM-5 zeolites have been investigated by cluster calculations with the ONIOM scheme and with an embedded-ONIOM scheme. The active site has been modeled with cluster sizes of up to 46 tetrahedra. Two different types of pyridine adsorption complexes on the zeolite models are found. If Zeolite is modeled by a small 3T quantum cluster, the adsorption energy of the hydrogen-bonded pyridine complex (Py-Hz), is found to be À18.5 kcal/mol. When a larger cluster or the ONIOM models are employed, the optimized geometries show the formation of pyrdinium cation [PyH + ] bound as an ion-pair complex [PyH + ][Z À ]. The calculated energy of formation for this ion-pair complex is À36.8 kcal/mol in the ONIOM (B3LYP/6-31G(d,p):UFF) model. Both values are considerably lower than the experimentally estimated heat of adsorption of pyridine in ZSM-5 zeolite of À47.6 kcal/mol. Inclusion of the electrostatic effects of the zeolite crystal lattice via the embedded ONIOM model increases the adsorption energy to À44.4 kcal/mol. Performing the quantum-chemical treatment at the MP2/6-31G(d,p) level instead of the B3LYP/6-31G(d,p) leads to a slightly lower adsorption energy to À45.9 kcal/mol. These data suggest that the embedded ONIOM scheme provides an accurate method of studying the interaction of small organic molecules with zeolites.

Polybenzene unit BTA_48, described by O'Keeffe et al. 20 years ago, to form a diamond-like fcc-net, by computer identification of octagons R(8), can also dimerize by identifying the ''opening'' rings R(12) when an ''intercalated'' dendrimer-dimer is formed. The dendrimer can grow up to the second generation and next the dendritic structure is completely superimposed over the diamond-like network. A third way of dimerization of BTA_48 is to an ''eclipsed'' isomer, that can form pentagonal hyper-rings. These can selfassemble into complex hollow-containing structures, of five-fold symmetry, called here multi-tori. They can evolve either radially or follow a linear periodicity. The polybenzene multi-tori, based on BTA_48, were compared to those based on BTZ_24, a unit earlier proposed by Diudea. A rational structure construction, based on operations on maps, is given for all the multi-tori and their subunits herein discussed. Their stability, relative to C 60 , was evaluated on the ground of calculations made at HF and DFT level of theory. The results showed a stability providing a pertinent hope in their future synthesis in laboratory. In this respect, the Infrared and Raman spectra of the units and their ''eclipsed'' dimers were simulated.

The structures and relative free energies in aqueous solution of the Cu(II) complexes of the ''histidine walk'' peptides, AcHGGGNH2, AcGHGGNH2, AcGGHGNH2, and AcGGGHNH2, were determined as a function of pH. Numerous structures of each species were found by gaseous-and solution-phase geometry optimization at the B3LYP/6-31G(d) level, and the effect of solvation estimated by the IEFPCM continuum solvation model. Free energies of solvation of the ionic species are large and favour structures with an extended peptide chain. In all Cu(II)-peptide complexes, deprotonation of two amide groups occurs readily at or below pH 7. In each system, the most abundant species at pH 7 is a neutral 1:1 complex with N3O1 coordination pattern. Binding in the forward direction toward the C terminus is preferred. The results are compared to recent experimental spectroscopic and potentiometric studies on related systems. Alternative explanations are offered for some of the experimental observations. Résumé : On a déterminé les structures et les énergies libres, en solutions aqueuses et en fonction du pH, des complexes de Cu(II) des peptides de la série histidine, AcHGGGNH 2 , ACGHGGNH 2 , AcGGHGNH 2 et ACGGGHNH 2 . On a déterminé les diverses structures de chacune des espèces, en phase gazeuse et en solution, par une optimisation de la géométrie au niveau B3LYP/6-31G(d) et on a évalué l'effet de solvatation par le modèle de solvatation continue IEEPCM. Les énergies libres de solvatation des espèces ioniques sont importantes et elles favorisent les structures avec une chaîne peptidique étendue. Dans tous les complexes Cu(II)-peptide, la déprotonation de deux groupes amides se produit facilement à des pH égal ou inférieurs à 7. Dans chaque système, l'espèce la plus abondante au pH 7 est un complexe 1:1 neutre comportant un patron de coordination N3O1. La fixation est favorisée dans la direction allant vers la position C-terminale. On compare les résultats obtenus ici avec ceux rapportés récemment pour des études expérimentales spectroscopiques et potentiométriques sur des systèmes apparentés. Des explications alternatives sont proposées pour un certain nombre d'observations expérimentales.

To subdivide the axis k into 2 new axes p and q, we place k=p+qN/r with p=0,1, ... , N/r s-1, s=0,1, ... ,logrN-1 and q = 0,1,...., r -1. Therefore, X(k) is replaced using new indices p and q where x [n] is the input sequence, X[k] is the output sequence, N is the transform length, w: k = e-j(2tr/N)nk is called the twiddle factor in the butterfly structure, and j2=_1. Both x [n] and X [k] are complex valued number sequences.

Ab initio harmonic force fields were calculated for 1,3,4-oxadiazole and 1,3,4-thiadiazole at the M¢ller-Plesset (MP2) level of theory using the 6-31G** basis set at the corresponding optimized geometries assuming a C2,, symmetry. Scaled quantum mechanical (SQM) force fields for both molecules were calculated using the experimental vibrational frequencies available from the literature. Under the C2,, symmetry constraint, the assignment of the experimental to the calculated frequencies for both molecules and their -2,5-d 2 and -2-d I (C~ symmetry) isotopomers was performed. Vibrational absorption intensities were calculated using the MP2 dipole derivative tensors. The calculations showed possible misassignment for 1,3,4-oxadiazole and its -2,5-d2 and -2-d~ isotopomers and indicated misassignments for 1,3,4-thiadizole and its -2,5-d and -2-dl isotopomers. Good agreement between the experimental and calculated frequencies and absorption intensities was found.

Abstract: 2-Ethoxy-6-[(E)-[(2-hydroxyphenyl)imino]methyl]phenol derivative Schiff bases (4-chloro-2-((3-ethoxy-2-hydroxybenzylidene)amino)phenol; 5S1 and 2-((3-ethoxy-2-hydroxybenzylidene)amino)-4-methylphenol; 5S2 have been synthesized and characterized with 1H-NMR, 13C-NMR, IR and elemental analysis in this study. The stable conformers and possible tautomer forms of Schiff base derivatives have been determined in theoretical calculations. All the calculations considering for the energetically stable conformers were performed with Gaussian09 program by using B3LYP/6-311g(2d,p) level of theory. The Gibbs Free energies, stable tautomer forms, H-bond, Mulliken charges, dipole moments, solvent accessibility surface areas (SAS), molecular electrostatic potential values, HOMO, LUMO and band gap energies (EGAP) were also calculated. The consistency between the theoretical and experimental 1H-NMR, 13C-NMR and IR spectra has also been investigated.

We investigate molecular scale mechanisms for radiation-induced release of hydrogen from precursor sites using density functional theory applied to a fully periodic model of SiO 2 . We focus on proton release from H-decorated oxygen vacancies in the bulk oxide. After hole-capture at the vacancy, a proton can hop to an energetically favorable bound state at a neighboring oxygen atom. In a-quartz, this release mechanism has an activation energy of about 1.2 eV. In amorphous silica, this hop has a range of low barriers, from 0.1 to 0.5 eV. Furthermore, another proton release mechanism involves cracking of H 2 molecules by a reaction with an isolated, positively charged Sidangling bond.

The structure and force field of pyridine-3-carboxamide (nicotinamide)-d 0 and-d 2 have been studied by IR spectra, ab initio and density functional calculations. According to the energy analysis, the E-conformer is more stable than the Zone. This result is in agreement with the correlation analysis performed (experimental vs theoretical IR frequencies), that indicates the same conformer is prevalent in CHCl 3 /CDCl 3 solutions, as well as in the solid state. Both ab initio and DFT force field calculations give good descriptions of the IR spectra of nicotinamided 0 and-d 2 studied, and fairly good ones for the corresponding isotopic shifts. The theoretical bond lengths and angles are in excellent agreement with those determined experimentally by electron and neutron diffractions. According to the calculations, the carboxamide group holds a negative electric charge and the Mulliken charge transfer between it and the b-pyridyl ring is 0.30 e K .

An optimized effective potential (OEP) approach based on density functional theory for individual excited states and a simple to implement method which takes the orthogonality constraints into account (TOCIA) for the Kohn–Sham determinants is developed with the aim of constructing the orbital-dependent correlation energy corrections. It is shown that the TOCIA methodology makes it possible to apply both the OEP experience and the perturbative second-order correction for the ground state to the excited state problem with the same computational effort. A performance of the proposed method is demonstrated by calculations of excitation energies for the Li atom and HeH and LiHe molecules at the different levels of approximation. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007

The FT-IR and Laser-Raman spectra of the title compound were recorded in solid phase. The optimized geometry and vibrational frequencies were calculated for the first time. The HOMO-LUMO energies and related molecular properties were evaluated. g r a p h i c a l a b s t r a c t

AbstractÐThe formation of methyl acrylate from formaldehyde and methoxyacetylene, and the in¯uence of BF 3 as a model Lewis acid are studied by means of ab initio HF and DFT calculations (HF/6-31G p and B3LYP/6-31G p ). In both cases calculations are in favour of a pathway involving the asynchronous (or stepwise) formation (the C±C bond being formed ®rst) of the reactive intermediate methoxy oxete, and its further electrocyclic ring-opening into methyl acrylate. q Scheme 1. Formation of a,b-unsaturated esters from carbonyl compounds and ethoxyalkynes under Lewis acid catalysis. Mechanism proposed by Vieregge et al. in 1966. 2

In many applications, it is desirable to have a fast algorithm (RFliT) for the computation of the real discrete Fourier transform (RDFf) for any number of data points N. To achieve this, the two-factor Cooley-Tukey decimation-in-time and decimation-in-frequency RFFI algorithms are first developed and expressed in terms of matrix factorization using Kronecker products. Then, this is generalized to any number of factors with arbitrary radices. Each factor M involves the computation of size h f RDFf which is carried Out by the best size-M m algorithm available. The m algorithm for M equal to a prime number is also developed. The RFFf algorithms are more efficient in the number of operations when the complex FliT algorithms, which have the same number of opera-and x(N-1 27rnk x(k , sink = O N ' O < n < N ;-n> = X o (n) =

RESUMEN El problema del deslizamiento de frecuencia asociado a la estimación digital de las magnitudes eléctricas, cuando se utiliza como algoritmo de medida la Transformada de Fourier es analizado en este artículo. Se mencionan algunos otros factores que influyen en la precisión de las medidas de tensión, corriente, potencia y frecuencia, y se obtienen analíticamente los errores de las señales básicas de tensión y de corriente, cuando la frecuencia del sistema tiene variaciones y se mantiene fija la frecuencia de muestreo del medidor. En la parte final, se presentan algunos resultados y las conclusiones obtenidas para la estimación de magnitudes eléctricas, cuando se tiene como entrada señales con contaminación armónica y con magnitudes diferentes a plena escala del medidor.

Although it is a time-domain method, the finitedifference time-domain (FDTD) method has been used extensively for calculating frequency domain parameters such as specific absorption rate, radar cross-section, and S-parameters. When a broad frequency band is of interest, using a broad-band pulsed excitation can provide this frequency response with a single FDTD simulation. The frequency domain data can be calculated from the time domain data using either a discrete Fourier transform (DFT) or a fast Fourier transform (FFT). This letter examines both methods and analyzes why the DFT is generally more efficient and easier to use than the FFT for FDTD time-tofrequency domain conversions.

Complete assignment of the 1 H and 13 C NMR spectra of all possible D D-glucopyranosyl-D D-glucopyranosides was performed and the 1 H chemical shifts and proton-proton coupling constants were refined by computational spectral analyses (using PERCH NMR software) until full agreement between the calculated and experimental spectra was achieved. To support the experimental results, the 1 H and 13 C chemical shifts and the spin-spin coupling constants between the non-hydroxyl protons of a-and b-D D-glucopyranose (1a and 1b) were calculated with density functional theory (DFT) methods at the B3LYP/pcJ-2//B3LYP/ 6-31G(d,p) level of theory. The effects of different glycosidic linkage types and positions on the glucose ring conformations and on the a/b-ratio of the reducing end hydroxyl groups were investigated. Conformational analyses were also performed for anomerically pure forms of methyl D D-glucopyranosides (13a and 13b) and fully protected derivatives such as 1,2,3,4,6-penta-O-acetyl-D Dglucopyranoses (14a and 14b).

The current study investigates the structural, elastic, electronic and optical properties of CeO 2 , PrO 2 and TbO 2 using the full potential (linearized) augmented plane wave plus local orbital method within the Wu-Cohen generalized gradient approximation (GGA) with Hubbard (U) correction and spin-orbit coupling (SOC). The GGA þ U implementation lead us to describe correctly the relativistic effect on 4f electrons for CeO 2 . We clarify that the inclusion of the Hubbard U parameter and the spin-orbit coupling are responsible for the ferromagnetic insulating of PrO 2 and TbO 2 . The magnetic description is achieved by the spin-density contours and magnetic moment calculations, where we show the polarization of oxygen atoms from the rare earth atoms. The mechanical stability is shown via the elastic constants calculations. The optical properties, namely the dielectric function and the reflectivity are calculated for radiation up to 12 eV, giving interesting optoelectronic properties to these dioxides.

Watermarking, which belong to the information hiding field, has seen a lot of research interest recently. There is a lot of work begin conducted in different branches in this field. Steganography is used for secret communication, whereas watermarking is used for content protection, copyright management, content authentication and tamper detection. In this paper we present a detailed survey of existing and newly proposed steganographic and watermarking techniques. We classify the techniques based on different domains in which data is embedded. Here we limit the survey to images only.

- Radix-2 FFT algorithm is the simplest and most common form of the Cooley-Tukey algorithm. This considers radix-2 FFT processors and realization of butterfly operations. The properties, e.g., area and power consumption, of the FFT processor depend mainly on implementation of butterfly operations. These algorithms have been developed using verilog hardware descriptive language. Butterfly unit method reduces the number of multiplications and additions compared to formula method.

Resumen-la FFT es la forma optimizada de la DFT, logrando así menos complejidad en sus algoritmos pudiéndose aplicar en temas "complejos" para realizar sus procedimientos de un manera más fácil o más analítica. Sus diferentes e innumerables aplicaciones dan a demostrar su gran efectividad en el campo de la ciencia y la ingeniería. Su énfasis en el tratamiento de imágenes y audio permite el análisis de datos retornando patrones que con análisis detallado se pueden desarrollar grandes aplicaciones.

This review aims to briefly outline the Hubbard-U scheme and to investigate the effect of its inclusion in standard Density Functional Theory on electronic, structural, and optical properties of ZnO wurtzite structure. To remedy the miscalculation of optimized lattice parameters determined by Local Density Approximation and Generalized Gradient Approximation approximations to experimental values, the effect of the implementation of Hubbard-U correction for only d state or for both d and p states was investigated for theoretical data collected from previous works. Further effort was devoted to studying the incorporation of U d,Zn and U p,O to reproduce correct band gap, to exploring various regions composed of valence and conduction bands and their origin, and to revealing the nature of chemical bonding. This review also provides graphical and tabulated values extracted from earlier works on optical properties of ZnO wurtzite structure. It summarizes the effect of U d,Zn and U p,O in several exchange-correlation functionals on the intensity and location of major peaks composed real and imaginary part of dielectric function as well as on the shift of main absorption peak and optical absorption edge. A comparison was made, wherever possible, between theoretical and experimental results.

An orthonormal transformation in N-dimensional space can be obtained by choosing a set of N mutually orthogonal vectors and then normalizing their lengths to make them unit vectors. Alternatively, we can start from N orthogonal continuous functions, unifromly sample each of them appropriately ensuring that the N-samples of each of them treated as vectors are still orthogonal to each other and then normalizing those vectors to form the basis. Orthogonality of sinusoids with rational frequency ratio: With continuous sinusoidal functions, the area under the curve obtained by the product of two sinusoids of frequency equal to different integer multiples of the same fundamental frequency is zero over one period of the fundamental frequency.

A new package for calculating the elastic constants of orthorhombic structure is released. The package called ortho-elastic. The formalism of calculating the ortho-elastic constants is described in details. The package is compatible with the highly accurate all-electron full-potential (linearized) augmented plane-wave plus local orbital [FP-(L)APW+lo] method implemented in WIEN2k code. Several orthorhombic structure compounds were used to test the new package. We found that the calculated elastic constants using the new package show better agreement with the available experimental data than the previous theoretical results used different methods. In this package the second-order derivative E 00 ðeÞ of polynomial fit E ¼ EðeÞ of energy vs strains at zero strain ðe ¼ 0Þ, used to calculate the orthorhombic elastic constants.

In this paper, the implementation of the discrete sine transform (DST) and its inverse (IDST) are developed. General length structure of the DST and IDST, which can be implemented by using the recursive structures, has been proposed. Necessary formulas required for the recursive structures have been derived using mathematical manipulations. Copyright © 2007 John Wiley & Sons, Ltd.

Density functional theory models developed over the past decade provide unique information about the structure of nanoscale defects produced by irradiation and about the nature of short-range interaction between radiation defects, clustering of defects, and their migration pathways. These ab initio models, involving no experimental input parameters, appear to be as quantitatively accurate and informative as the most advanced experimental techniques developed for the observation of radiation damage phenomena. Density functional theory models have effectively created a new paradigm for the scientific investigation and assessment of radiation damage effects, offering new insight into the origin of temperature-and dose-dependent response of materials to irradiation, a problem of pivotal significance for applications. 35 Annu. Rev. Mater. Res. 2013.43:35-61. Downloaded from www.annualreviews.org by University of Oxford -Bodleian Library on 07/08/13. For personal use only. Further ANNUAL REVIEWS 36 Dudarev Annu. Rev. Mater. Res. 2013.43:35-61. Downloaded from www.annualreviews.org by University of Oxford -Bodleian Library on 07/08/13. For personal use only.

Resumen. En el presente reporte se explica el proceso de implementación de un algoritmo que obtiene la transformada discreta de Fourier de una secuencia finita de muestras. Se utiliza el lenguaje de programación C para implementar el algoritmo en la herramienta de desarrollo Code Composer Studio 6.0. El algoritmo se descarga en una tarjeta de la serie TIVA C de Texas Instruments, la cual realizará el muestreo de una señal analógica, el procesamiento de esas muestras a través del algoritmo y enviará sus resultados a una computadora portátil por medio de la comunicación serial. Por último, mediante una aplicación en Java se procesan los datos obtenidos con la tarjeta y se grafican. Palabras clave: algoritmo, programación, señal analógica, transformada discreta de Fourier.

I nterest in the chemistry of the early actinide elements (notably uranium through americium) usually results either from the nuclear waste problem or the unique chemistry of these elements that result from 5f contributions to bonding. Computational actinide chemistry provides one useful tool for studying these processes.

In this review, we present a summary of the research work performed so far using high accuracy quantum chemical methods on polyphenolic antioxidant compounds. We have reviewed the different groups of polyphenols, which mostly belong to the Mediterranean food culture, i.e. phenolic acids, flavonoids and stilbenes. The three main proposed mechanisms through which the antioxidants may play their protective role, which is the H atom transfer, the single electron transfer and the metals chelation, have been analysed and discussed in details. This work represents a further important contribution to the elucidation of the beneficial effects on health of these substances.

An implementation of IEEE 1149.1 TAP controller is presented in this paper. JTAG is an established technology and industry standard for on-chip boundary scan testing of SoCs. JTAG TAP controllers are becoming a delivery and control mechanism for Design For Test. The objective of this work is to design and implement a TAP controller IP core compatible with IEEE 1149.1-2013 revision of the standard. The test logic architecture also includes the Test Mode Persistence controller and its associated logic. This work is expected to serve as a ready to use module that can be directly inserted in to a new digital IC designs with little modifications.

In this study, the special quasi-random structure (SQS) approach has been
considered for structural, electronic and optical properties of rock-salt (RS) and zinc-blende
(ZB) phases of ZnO 1− x Te x (x= 0, 0.25, 0.5, 0.75 and 1) using density functional theory.
The Wu–Cohen generalized gradient approximation (GGA) has been employed for
optimizing the lattice parameters (a 0) and bulk moduli (B 0) in both phases which show
reasonable agreement with numerous theoretical and experimental results. To compute

In this paper we present two designs of CMOS blocks suitable for integration with RF frontend blocks for test purposes. Those are a programmable RF test attenuator and a reconfigurable low noise amplifier (LNA), optimized with respect to their function and location in the circuit. We discuss their performances in terms of the test- and normal operation mode. The presented application model aims at a transceiver under loopback test with enhanced controllability and detectability. The circuits are designed for 0.35μm CMOS process. Simulation results of the receiver frontend operating in 2.4 GHz band are presented showing tradeoffs between the performance and test functionality.

Recent literature on synthesis gas conversion to higher alcohols over Mo-based catalysts is reviewed. Density functional theory calculations show that Mo-CO adsorption is weakened by C, P, or S ligands and this facilitates CO dissociation, either directly on Mo 2 C, or by H-assisted dissociation on MoS 2 , Mo 2 C, and MoP. Consequently, Mo-based catalysts have high hydrocarbon selectivity unless they are promoted with alkali metals and/or Group VIII metals. Promoted MoS 2 and MoP have alcohol selectivities of ∼80 C atom % (CO 2 -free basis) at typical operating conditions (5-8 MPa, H 2 /CO = 2-1, 537-603 K), whereas on promoted Mo 2 C, alcohol selectivities are ∼60%. The kinetics of the synthesis gas conversion reactions over Mo-based catalysts have mostly been described by empirical power law models and the alcohol and hydrocarbon product distributions are consistent with a CO insertion mechanism for chain growth.

Ring-opening of epoxides with boron trifluoride yielding syn-fluorohydrins was investigated using density functional methods (PBE) and two different basis sets (6-31G(d) and 6-311++G(2df,2pd), both in gas phase and simulating the bulk solvent using the PCM method. The only mechanism previously suggested for the formation of fluorohydrins from epoxides is an S N 1-like one. We propose in this work a new mechanism, in which bond breaking in the epoxide is coupled to fluorine transfer, yielding the fluorohydrine with retention of configuration through a single transition state.

We report a systematic first principles density functional study on the electronic structure, elastic and optical properties of nitrogen based solid hydrogen storage materials LiNH 2 , NaNH 2 , KNH 2 , and RbNH 2 . The ground state structural properties are calculated by using standard density functional theory, and also dispersion corrected density functional theory. We find that van der Waals interactions are dominant in LiNH 2 whereas they are relatively weak in other alkali metal amides. The calculated elastic constants show that all the compounds are mechanically stable and LiNH 2 is found to be a stiffer material among the alkali metal amides. The melting temperatures are calculated and follow the order RbNH 2 < KNH 2 < NaNH 2 < LiNH 2 . The electronic band structure is calculated by using the Tran-Blaha modified Becke-Johnson potential and found that all the compounds are insulators, with a considerable band gap. The [NH 2 ] − derived states completely dominate in the entire valence band region while the metal atom states occupy the conduction band. The calculated band structure is used to analyze the different interband optical transitions occurring between valence and conduction bands. Our calculations show that these materials have considerable optical anisotropy.

A detailed study of the action of alkali on methylene blue (C.I. Basic Blue 9) and other thiazine dyes was carried out through a combination of UV/visible spectroscopy, thin layer chromatography, mass and NMR spectrometry and computational methods. In 0.1 M aq alkali solution, methylene blue forms a highly coloured, lipophilic species that is mainly Bernthsen's methylene violet i.e. a hydrolysis decomposition product, this being contrary to the report of a red N-hydroxy methylene blue adduct. The nature of the heterocyclic nitrogen atom in C.I. Basic Blue 9 is discussed and it is concluded there is no basis for the proposal of nucleophile addition at this site of the dye. In contrast, other thiazine dyes are deprotonated by alkali to form their neutral, highly coloured, lipophilic conjugate base forms.

The embedded core testing methodology at Advanced Micro Devices Inc. Involves adopting a disciplined system for developing new products with a focus on time to market and engineering productivity. A key factor is to achieve high and verifiable fault coverage for designs by closely adhering to guidelines and by increased test automation. This paper addresses the design for test (DFT) aspects of the methodology, production testing of embedded CPU cores, and provides some data on completed designs