Quantum codes from nearly self-orthogonal quaternary linear codes

Construction X and its variants are known from the theory of classical error control codes. We present instances of these constructions that produce binary stabilizer quantum error control codes from arbitrary quaternary linear codes. Our construction does not require the classical linear code \(C\) that is used as the ingredient to satisfy the dual containment condition, or, equivalently, \(C^{\perp _h}\) is not required to satisfy the self-orthogonality condition. We prove lower bounds on the minimum distance of quantum codes obtained from our construction. We give examples of record breaking quantum codes produced from our construction. In these examples, the ingredient code \(C\) is nearly dual containing, or, equivalently, \(C^{\perp _h}\) is nearly self-orthogonal, by which we mean that \(\dim (C^{\perp _h})-\dim (C^{\perp _h}\cap C)\) is positive but small.     

Imaging of nanostructures with sub-100?nm spatial resolution using a desktop EUV microscope

Laser-produced plasma sources of short-wavelength radiation offer an interesting alternative to synchrotron and free-electron laser installations. Recently, we reported on a newly developed desktop EUV microscope based on plasma generated from a gas-puff target and diffractive optics. The half-pitch resolution of the microscope approached 50?nm. Compared to analogous microscopes based on synchrotron sources, our system is compact and cost-effective. In this paper, we present the results of imaging experiments on a thin polycrystalline object that was carried out in order to further examine the applicability of the microscope. We have demonstrated here that EUV microscopy can provide structural information that cannot be accessed by conventional optical microscopy or SEM.     

Approximations of spectra of Schrödinger operators with complex potentials on ℝd

We study spectral approximations of Schrödinger operators T = ?Δ+Q with complex potentials on Ω = ?^d, or exterior domains Ω??^d, by domain truncation. Our weak assumptions cover wide classes of potentials Q for which T has discrete spectrum, of approximating domains Ω_n, and of boundary conditions on ?Ω_n such as mixed Dirichlet/Robin type. In particular, Re Q need not be bounded from below and Q may be singular. We prove generalized norm resolvent convergence and spectral exactness, i.e. approximation of all eigenvalues of T by those of the truncated operators T_n without spectral pollution. Moreover, we estimate the eigenvalue convergence rate and prove convergence of pseudospectra. Numerical computations for several examples, such as complex harmonic and cubic oscillators for d = 1,2,3, illustrate our results.     

Affinity capillary electrophoretic study of K+/Na+ selectivity of hexaarylbenzene-based polyaromatic receptor

Affinity capillary electrophoretic (ACE) study has proved the selectivity of hexaarylbenzene-based polyaromatic receptor (R) for K⁺ ion over Na⁺ ion. The apparent binding constants of the R complexes with K⁺ and Na⁺ ions were determined from the dependence of effective electrophoretic mobility of R on the concentration of the above alkali metal ions in the background electrolyte using a non-linear regression analysis. The apparent binding constants (K_b) of the K-R⁺ and Na–R⁺ complexes in methanolic medium were evaluated as log K_b = 3.20 ± 0.22 for the K–R⁺ complex, and log K_b??0.7 for the Na–R⁺ complex.     

Introducing an amine group to calix[5]arene: comparison of several methods

Abstract

Chemists often use an amine group as an intermediate in syntheses of imines, amides and ureas; however, in the case of syntheses of p-aminophenol type compounds, several problems might occur. In this article, we prepared p-aminocalix[5]arene-pentaol by reduction of both nitro and azo derivatives, and compared four methods of the amine preparation, focusing mainly on its gramme scale and time-consuming issues.     

DFT-calculated structure of protonated tetraphenyl p - tert -butylcalix[4]arene tetraketone

Using DFT calculations, two of the most probable structures (A, B) of the tetraphenyl p-tert-butylcalix[4]arene tetraketone·H₃O⁺ cationic complex species were derived. The hydroxonium ion H₃O⁺, placed in the coordination cavity formed by the calix[4]arene lower-rim groups, is bound by strong hydrogen bonds to the phenoxy oxygen atoms of the calix[4]arene ligand (structures A, B) and also to one carbonyl oxygen (structure B).     

Metallopyrrole-capped carbon nanocones

We design nickel-doped and nitrogen-doped carbon nanocones with various amounts of buckling that feature square-planar, (approximate) tetrahedral, and octahedral coordination. The optimized geometries and electronic structures of these novel metallocarbon complexes are calculated by using the B3LYP (Gaussian03) and GGA-BLYP (ADF) exchange-correlation functionals. We analyze buckling and stability of the nanocones, and discuss their potential for additional functionalization at the metallic site.     

Microfluidics for multiplexed MS analysis

Recent advances of microfluidics systems suitable for multiplexed MS analysis are reviewed with respect to fabrication technologies and applications.     

Separation of phenolic acids by capillary electrophoresis with indirect contactless conductometric detection

A new method for the electrophoretic separation of nine phenolic acids (derivatives of benzoic and cinnamic acids) with contactless conductometric detection is presented. Based on theoretical calculations, in which the mobility of the electrolyte co- and counterions and mobility of analytes are taken into consideration, the electrolyte composition and detection mode was selected. This approach was found to be especially valuable for optimization of the electrolyte composition for the separation of analytes having medium mobility. Indirect conductometric detection mode was superior to the direct mode as predicted theoretically. The best performance was achieved with 150 mM 2-amino-2-methylpropanol electrolyte at pH 11.6. The separation was carried out in a counter-electroosmotic mode and completed in less than 6 min. The LODs achieved were about 2.3-3.3 microM and could be further improved to 0.12-0.17 microM by using a sample stacking procedure. The method compares well to the UV-Vis detection.     

Conformational flexibility of L-alanine zwitterion determines shapes of Raman and Raman optical activity spectral bands

Detailed analysis of Raman and Raman optical activity (ROA) of L-alanine zwitterion (ALAZW) revealed that shapes of the spectral bands are to a large extent determined by the rotation of the NH(3)(+), CO(2)(-), and CH(3) groups. Aqueous solution ALAZW spectra were measured down to 100 cm(-1) and compared to complex simulations based on ab initio (B3LYP/CPCM/6-31++G**) computations of molecular energies and spectral parameters. The bands exhibit different sensitivities to the motion of the rotating group; typically, for more susceptible bands the Raman signal becomes broader and the ROA intensity decreases. When these dynamical factors are taken into account in Boltzmann averaging of conformer contributions, simulated spectra not only better agree with the experiment, but shapes of the rotational potentials can be estimated. Effects of the molecular flexibility could be also demonstrated on differences in Raman spectra of the solution, crystalline, and glass (gellike) solid states of ALAZW. Experimental Raman and ROA spectra of four model dipeptides of different rigidities (Ala-Pro, Pro-Ala, Pro-Gly, and Gly-Pro) indicate that the broadening of spectral lines can be used as a general site-specific indicator of molecular rigidity or flexibility.