The [20.4]Φ→(1)Δ Green System of LaF

Electronic bands belonging to the [20.4]³Φ→(1)³Δ system have been observed in the emission spectrum of lanthanum monofluoride at high temperature in the presence of the Ar⁺ 457.9-nm laser line: the (0-0), (1-1), (2-2), and (3-3) bands of the ³Φ₄→³Δ₃ subsystem and the (0-0) bands of the ³Φ₃→³Δ₂ and ³Φ₂→³Δ₁ subsystems. Rotational structures which are well developed in these experimental conditions were analyzed. The data were treated using a polynomial expression for the upper levels term-values, directly at equilibrium for ³Φ₄, whereas a previous Hamiltonian matrix representation of the (1)³Δ state was assumed. A Hund's case (a) representation of the [20.4]³Φ state at v=0 was also considered. Perturbations affecting ³Φ₂ levels at v=0 were observed; the energy and rotational constant of the perturbing state and the interaction parameter were estimated.     

New one-pot synthesis of spiro[furo[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidine-6,5′-pyrimidine]pentaones and their sulfur analogues

Reaction of barbituric acid (BA), 1,3-dimethyl barbituric acid (DMBA) and 2-thiobarbituric acid (TBA) with cyanogen bromide and various aldehydes in presence of triethylamine afforded a new class of heterocyclic stable 5-alkyl and/or 5-aryl-1H, 1′H-spiro[furo[2,3-d]pyrimidine-6,5′-pyrimidine]2,2′,4,4′,6′(3H,3′H,5H)-pentaones which are dimeric forms of barbiturate (uracil and thiouracil derivatives) at 0 °C to ambient temperatures. Structure elucidation is proved by X-ray crystallography, ¹H NMR, ¹³C NMR, FT-IR, CHN and mass analyses techniques. Mechanisms of the formations are discussed.     

Comparison of the calculated electronic structures of [111] and [001] GaAs/AℓxGa1-xAs semiconductor superlattices

A theoretical comparison of the electronic structures of long-period (about 300 Å) N_GaAs×N_AℓGaAs GaAs/Aℓ_0.3Ga_0.7As superlattices grown along the [111] direction and superlattices grown along the [001] direction is presented. Almost all qualitative features of the theoretical results are in good agreement with experiments by Hayakawa et al. The observed optical transition enhancement in the [111]-oriented quantum-well structures is caused by the topological difference in the superlattices, and is only partly due to the fact that the heavy holes in the [111] superlattices have larger transverse effective masses, and therefore have larger two-dimensional valence band densities of states.     

Synthesis of novel 7-aryl and 7-spiropyrazolo[4′,3′:5,6]pyrido[2,3-<Emphasis Type="BoldItalic">d</Emphasis>]pyrimidine derivatives and their study as AChE inhibitors

An efficient route for the synthesis of novel 7-aryl and 7-spiropyrazolo[4\(^{\prime }\),3\(^{\prime }\):5,6]pyrido[2,3-d]pyrimidine derivatives is described. These compounds were obtained by a cyclocondensation reaction between pyrazolopyridinediamines 4 and aldehydes 5 or cyclic ketones 6 in the presence of acetic acid as catalyst. This procedure provides the desired compounds in good yields under a simple two-step methodology. The obtained compounds were evaluated as AChE inhibitors and showed weak AChe inhibition with \(\hbox {IC}_{50} = 115{-}470 \, \upmu \hbox {M}\).     

Reply to: “Comment on: ‘Exposed-key weakness of αη’ [Phys. Lett. A 370 (2007) 131]” [Phys. Lett. A 372 (2008) 7091]

We present simulations countering the claims in [R. Nair, H.P. Yuen, Phys. Lett. A 372 (2008) 7091] that the approximation given in [C. Ahn, K. Birnbaum, Phys. Lett. A 370 (2007) 131, quant-ph/0612058] for the eavesdropper's entropy on the encrypted key cannot be valid, and additionally discuss ways in which our views on security requirements differ from those given in [R. Nair, H.P. Yuen, Phys. Lett. A 372 (2008) 7091].     

The effect of solvation on spectral-luminescence properties of 2,2-difluoro-4-methylnaphto-[2,1-<Emphasis Type="Italic">е</Emphasis>]-1,3,2-dioxaborine

The processes of formation and dissociation of aggregates and formation of solvates of 2,2-difluoro- 4-methylnaphto-[2,1-е]-1,3,2-dioxaborine (1) with the chloroform molecule have been investigated by the methods of stationary and time-resolved spectroscopy. It has been revealed that, in the case of solutions in chloroform, a slow (within 1 h) dissociation of aggregates under the effect of solvent molecules takes place. It has been demonstrated that using chloroform as a solvent allows varying the content of luminophor aggregates in the polymeric composite and, thus, controlling the material spectral-luminescence properties.     

Intermediate phases in [111]- and [001]-oriented PbMg<Subscript>1/3</Subscript>Nb<Subscript>2/3</Subscript>O<Subscript>3</Subscript>–29PbTiO<Subscript>3</Subscript> single crystals

Phase transformations in [111]- and [001]-oriented PbMg_1/3Nb_2/3O₃–29PbTiO₃ single crystals have been studied using dielectric and optical measurements before and after applying an electric field. It is shown that the subsequence of phase transitions rhombohedral (R)—tetragonal (T)—cubic (C) phases is observed in nonpolarized samples of both orientations as temperature increases. In the [111]-oriented crystal, an additional intermediate monoclinic phase (it is possible, M _a ) is induced after preliminary polarization at room temperature and the R–M _a –T–C phase transitions are observed on heating. In the [001]-oriented crystal, after its polarization, the monoclinic phase forms instead of the rhombohedral phase even at room temperature and the M _a –T–C transitions occur on heating. The results are discussed from the point of view of the existence polar nanoregions with different local symmetries in a glasslike matrix.     

Structure of the product of intracomplex alkylation of target octanucleotide pd[TGTTTGGC] by means of 4-[N-methyl-N-(2-chloro-ethyl)-amino]benzyl-5′-phosphamido derivative of heptanucleotide pd[CCAAACA]: Two-dimensional1H-NMR spectroscopy and restrained molecular mechanics refinement

The spatial structure of a covalent adduct — the product of intracomplex alkylation at N-3-position of dC-8 nucleoside residue of target octanucleotide pd[TGTTTGGC] by means of 4-[N-methyl-N-(2-chloroethyl)amino]benzyl-5′-phosphamido derivative of heptanucleotide pd[CCAAACA] — has been investigated in aqueous solution by two-dimensional (2D)¹H-NMR spectroscopy and restrained molecular mechanics calculations. By using COSY, COSY-DQF and NOESY experiments the assignment of oligonucleotide protons as well as protons of modifying group was carried out. The correlation times of benzylamide fragment protons and those of neighbouring nucleotide residues dC-1 and dC-8 were shown to be equal and shorter thanτ _c of intraduplex nucleotides. The analysis of proton-proton coupling constants for H1′, H2′a, H2′b and H3′ protons showed all sugar residues to be in 2′-endo conformation. The distances between protons closed in the space were determined by means of a set of one-dimensional (1D) NOE experiments. The experimental distances were used as the constraints for energy minimization by molecular mechanics calculations. Eight conformations of benzylamide fragment of the covalent adduct differed with orientations of 4-N-methyl residue of the alkylating group and 1-methyleneamide linker function were constructed as starting structures in energy minimization procedure. Among of the resulting optimized structures only one S(Alk)8^* was found to satisfy both experimental data and energetic criteria. The benzylamide fragment in conformation S(Alk)8^* has been shown to localize in the region of lacked nucleoside residue of the duplex at the end of heptanucleotide chain less than 5 Å apart from the residues dC-1 and alkylated dC-8.     

Influence of Intrinsic Decoherence on Nonclassical Effects of System of a Three-LevelAtom in [1] Configuration

With the help of an SU(3) dynamicalalgebraic structure, we ~nd an exact solutionof the Milburn equationfor the system of a three-levelatom in the [1] configuration interacting with one quantized field mode with arbitrary detuning ,The exact solution is then used to discuss the influence of the intrinsic decoherence on the nonclassical properties of the system,such as collapes and revivals of the atomic populations,oscillations of the photon number distribution,and squeezing of the radiation field.     

The effect of microtacticity on the glass temperature of poly[α-methyl styrene]

The effect of micrestructure on the glass temperature Tg of poly (α-methyl styrene) has been investigated. It has been observed that T_g increases as the syndiotacticity of the molecule increases-thus T_g = 446 ± 2°K for polymer with 67% syndiotactic placements, while a value of T_g = 453 ± 2°K is found for a sample with 95% syndiotactic placements. Coefficients of expansion for the liquid and glassy states have been calculated and from these a chain stiffness parameter δε/k has been estimated using the Gibbs-DiMarzio theory. The result indicates that the flex energy of the α-methyl styrene chain is 20% larger than for the polystyrene chain.     

Corrigendum to “Qualitative analysis of trapped Dirac fermions in graphene” [Ann. Physics 349 (2014) 268–287]

In the article, one set of solutions of (−iσ₁∂_x+W(x)σ₂+Mσ₃)ψ=±Mψ$(-i{\sigma }_1{\partial }_x+W\left(x\right){\sigma }_2+M{\sigma }_3)\psi =\pm M\psi$ was not discussed. We provide corrections where the existence of this set is taken into account.     

White-light-emitting devices based on Nile Red and π electron rich [Zn<Subscript>4core</Subscript>] complex

A white organic light-emitting device was fabricated with a structure of ITO/PEDOT: PSS (45 nm)/PVK: Nile Red: [Zn_4core] (75 nm)/BCP (25 nm)/Al. Without Nile Red green and with Nile Red white emission was achieved. When the concentration of the Nile Red in thin film increased from 0.01 to 0.5 wt%, a white emission achieved. The electroluminescence spectra of the device cover a wide range of visible region with two peaks around 501 and 618 nm. It is noteworthy that a white and pure white OLEDs with an incomplete energy transfer from the green host [Zn_4core] to the dopant (Nile Red) was obtained in this work using a single emissive layer relative to the multi layered light emitter ones in white OLED devices. For 0.1 doped device, a maximum luminance efficiency of 2.54 cd/A with CIE coordinates of (x, y = 0.35, 0.37) at 230 mA/cm² has was achieved.     

[15N]Methacetin-und [15N]Ammoniumtest zur Leberfunktionsprüfung im Kindesalter

The stable isotope content of samples of precipitation and of the river water throughout the Piracicaba basin in Brazil was measured over a two-year period. The isotope values of precipitation follow a consistent pattern of relatively depleted values of both deuterium and oxygen 18 during the rainy summers and enriched ones during the dry winters, with all values aligned slightly above the Global Meteoric Water Line. The isotopic composition of the river water throughout the basin shows a remarkable spatial coherence and much smaller scatter of data than those of the precipitation. The isotope composition of river water is close to that of the precipitation in the rainy season, however, with a consistent lower d-excess value by 1‰–2‰. This is attributed to evaporative water loss in the basin, in part an expression of the recycling of water due to the anthropogenic activity in the region. The more divergent values are recorded during high-water stages in the rivers. In many cases, the floods during the beginning of the rainy season are characterized by an enrichment of the heavy isotopes and lower d-excess values when compared to the precipitation, with the opposite situation later in the rainy season. This is interpreted as resulting from the watershed/riverflow interaction pattern, and it thus suggests that the isotope composition can monitor the hydrologic situation in the basin and its changes.     

Raman Spectra of the Calix[n]arene—C60 Complex

We have obtained the Raman spectra of the Calix[n]arene C60 complex of anti-conformation.Very different interactions between C60 and calix[n]arene (n=4,8) have been found from the vibratory spectroscopy,which are more complicated than those reported in previous works.It is interesting to find three low frequency modes,i.e.the spheroidal,torsional and E2 clearly shown at 39,130 and 208cm^-1,respectively.It is primarily interpreted as a relaxation effect of calix[8]arene framework for C60 where the intramolecular bridge between C60 and calix[8]arene are partly packed and two axes of c60([100] and [101]) are changed from the original configuration.The change of the vibratory environment of the carbon atom of C60 created some new modes.The Hg5 mode(at 1101cm^-1) and Hg2(at 431cm^-1) have been split and some modes (Ag2 and other six Hg modes) were hidden.     

The crystal structure of kettnerite,CaBi[OF¦CO3]

Macroscopic, microscopic, goniometric, qualitative spectrographic and quantitative chemical data of kettnerite [2] with some new observations are given. The unit cell dimensions determined from the powder and rotating crystal photographs area ₀=b ₀=5.36±0.02 Å,c ₀=13.59±0.03 Å. There are four molecules in the unit cell. The crystal structure of kettnerite was studied from the ordinary and generalized projections of the Patterson function along the [010] axis. Direct evidence of tetragonal layers (Ca. 2 F, Ca) and (Bi, 2 O, Bi) parallel to the basal face was found. The spatial arrangement of these layers corresponds to the symmetry of the space groupP 4/nmm. These layers alternate in the [001] direction being interleaved by single CO₃ layers. Both the biaxial character of the mineral and the uncertainty concerning the rotation of the CO₃ groups indicate a lower, most probably an orthorhombic symmetry. The highest possible symetry is that ofCmma. The structure is related to that of the typeX ₁ found by Sillén et al. for several bismuth oxyhalides and especially to that of bismutite.

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CaBi[OF¦ CO₃]

, , , [2] . , :a ₀=b ₀=5,36±0,02 Å, ₀=13,59±0,03 Å;Z=4. [010]. (Ca, 2 F, ) (Bi, 2 O, Bi), (010). 4/. , ₃. ₃ . C. , , ₁, .

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We wish to express gratitude to our colleagues Dr. A. Línek and Ing. C. Novák (Institute of Technical Physics, Czech. Acad. Sci.) for the use of the M1 equipment [11]. We are also very grateful to Mr. Z. iký for carrying out most of the numerical calculations.     

Comment on: “Exposed-key weakness of αη” [Phys. Lett. A 370 (2007) 131]

We show that the insecurity claim of the αη cryptosystem made by C. Ahn and K. Birnbaum in [C. Ahn, K. Birnbaum, Phys. Lett. A 370 (2007) 131] under heterodyne attack is based on invalid extrapolations of Shannon's random cipher analysis and on an invalid statistical independence assumption. We show, both for standard ciphers and αη, that expressions of the kind given by Ahn and Birnbaum can at best be interpreted as security lower bounds.     

Coupled motion of [10−10] tilt boundaries in magnesium bicrystals

Magnesium bicrystals were grown with symmetric and asymmetric tilt boundaries about the [10–10] axis using the vertical Bridgman technique. Isothermal constant load tensile tests were conducted on these bicrystals in the temperature range 300–500°C and relative displacements of the two grains were measured to obtain an appreciation for grain boundary motion characteristics. Coupled grain boundary motion was noted in almost all cases with the degree of tangential motion versus migration changing with tilt misorientation, temperature and applied stress. Specifically, within the family of symmetric bicrystals evaluated, a minimum in grain boundary displacement in the specimen plane was observed at a tilt misorientation of 20°. In specific stress/temperature regimes, rigid body sliding was observed for the particular case of a 35° asymmetric tilt misorientation. The ease of basal and prism slip in magnesium at the temperatures considered and the consequential impingement of intragranular dislocations on the bicrystal boundary and their decomposition and motion along the boundary are thought to play an important role in the observed coupled motion of these tilt boundaries.