Fabrication of blazed gratings by area-coded effective medium structures

Area-coded effective medium structures (ACES) are a recently presented novel type of diffractive structure. Because of their higher stability compared to 2D binary blazed gratings, they have the potential of a broader use in micro-optics applications. The first fabrication with electron-beam lithography validate the theoretical model of blazed ACES. The measured diffraction efficiencies are in very good agreement with the values obtained from rigorous electromagnetic analysis.     

Distributed computation of Pareto solutions inn-player games

The problem of computing Pareto optimal solutions with distributed algorithms is considered inn-player games. We shall first formulate a new geometric problem for finding Pareto solutions. It involves solving joint tangents for the players' objective functions. This problem can then be solved with distributed iterative methods, and two such methods are presented. The principal results are related to the analysis of the geometric problem. We give conditions under which its solutions are Pareto optimal, characterize the solutions, and prove an existence theorem. There are two important reasons for the interest in distributed algorithms. First, they can carry computational advantages over centralized schemes. Second, they can be used in situations where the players do not know each others' objective functions.     

Turbo Coding with Equalization in WCDMA Downlink

In this paper, the performance of turbo coding in WCDMA downlink is considered in conjunction with receivers using two adaptive channel equalizers. Bit error and frame error rates are compared to the performance of the conventional Rake receiver. Special consideration is given to the cases with two receive antennas, the efficiency of the channel interleaver, the number of iterations in decoding, the performance with various numbers of users, the influence of mobile receiver velocity as well as to the effect of power control. The simulation results show that turbo coding, combined with power control and channel equalizers is a very efficient way to implement reliable data transmissions in WCDMA downlink. The results in the paper also verify that the adaptive channel equalizers is a very promising technique to improve the receiver performance and increase the user capacity.     

Synthesis of a novel carboxy functionalized PyOX-ligand

A short and convenient synthesis of a carboxy functionalized PyOX-core is presented. The carboxy functionality offers a wide variety of possibilities for further modification. In this paper, the core is functionalized with a mercapto tail.     

Investigation of a possible solvent cage effect in the reduction of 4-aminocyclohexanone by a hydroxycyclopentadienyl ruthenium hydride

No solvent cage effect could be found in the reduction of 4-aminocyclohexanone 3 by Shvo's hydroxycyclopentadienyl ruthenium hydride 2. No preference was observed in the complex formation from trapping by aminoalcohol product 4 over external trapping by aminoketone 3 or by Shvo hydride 2. A solvent cage effect has previously been proposed to support an outer-sphere mechanism in the reduction of imines by 2; this was based on the observation that there was >90% preference for complexation of the newly formed amine over an external amine. Since alcohols form stronger hydrogen bonds than amines a larger cage effect would be expected in the present study. The lack of a cage effect in the present reduction suggests that the previous results from imine reduction require an additional explanation (other than a solvent cage effect).     

Feature detection and alignment of hyphenated chromatographic-mass spectrometric data. Extraction of pure ion chromatograms using Kalman tracking

In this paper we present a new method, called TracMass, for analyzing data obtained using hyphenated chromatography-mass spectrometry (XC/MS). The method uses a Kalman filter to extract pure, noise-free ion chromatograms by exploiting the latent second order structure in the XC/MS data. TracMass differs from current state-of-the-art methodologies, which extract chromatograms by binning along the m/z axis and further processes the data in various ways, e.g. by baseline correction, component detection algorithm, peak detection, and curve resolution to extract molecular features. The proposed method was validated by analyzing two plasma datasets: one derived from 99 quality control samples where TracMass extracted 8880 Pure Ion Chromatograms (PICs) present in > or =90 of the samples. The second dataset was spiked with two different internal standard mixtures to test differential expression analysis. Here TracMass found 20000 PICs present in 10 samples, all differentially expressed analytes, and also a previously unreported discriminating metabolite. Finding as many PICs as possible is in this context essential to ensure that even small differentiating features are found (if they exist). The resulting data representation from TracMass (PICs) can be used directly for statistical analysis, and the method is fast (approximately 5min/sample), with few adjustable parameters.     

Heterogeneous multicomponent nucleation theorems for the analysis of nanoclusters

In this paper we present a new form of the nucleation theorems applicable to heterogeneous nucleation. These heterogeneous nucleation theorems allow, for the first time, direct determination of properties of nanoclusters formed on pre-existing particles from measured heterogeneous nucleation probabilities. The theorems can be used to analyze the size (first theorem) and the energetics (second theorem) of heterogeneous clusters independent of any specific nucleation model. We apply the first theorem to the study of small water and n-propanol clusters formed at the surface of 8 nm silver particles. According to the experiments the size of the two-component critical clusters is found to be below 90 molecules, and only less than 20 molecules for pure water, less than 300 molecules for pure n-propanol. These values are drastically smaller than the ones predicted by the classical nucleation theory, which clearly indicates that the nucleating clusters are too small to be quantitatively described using a macroscopic theory.     

High-energy conformer of formic acid in solid neon: giant difference between the proton tunneling rates of cis monomer and trans-cis dimer

We study the conformational reorganization of formic acid (FA) in solid neon and report the higher-energy cis-FA monomer and one form of the trans-cis FA dimers. They were prepared by selective vibrational excitation of the trans-FA monomer and trans-trans dimer. The proton tunneling decay of cis-FA monomer is surprisingly very fast in solid neon, two orders of magnitude faster than in solid argon. It was also found that the stability of the trans-cis dimer against proton tunneling is enormously enhanced in solid neon compared to the monomer (by a factor of approximately 300). These results are discussed in terms of matrix solvation and hydrogen bonding.     

Computational study of the reaction between biogenic stabilized Criegee intermediates and sulfuric acid

We have postulated a mechanism for the reaction of sulfuric acid with stabilized Criegee intermediates (sCIs). We have computed Gibbs free energies for the reaction of sulfuric acid with two biogenic sCIs and three smaller model species. We have also calculated Gibbs free energies for two competing sink reactions. Due to the large size of the biogenic sCIs, the computations have been performed at the relatively modest B3LYP/6-31G(d,p) and B3LYP/6-311+G(2d,p) levels. However, single-point RI-CC2/def2-QZVPP calculations for the (CH3)(2)COO model species are in good agreement with the B3LYP results. The reaction is found to be strongly exothermic for all studied species. Activation barrier calculations on the (CH3)(2)COO model species further indicate that the reaction with sulfuric acid may proceed significantly faster than the sink reaction with water. If the same applies to the biogenic sCIs, the proposed reactions could account for some part of the organically assisted new particle formation events observed in the atmosphere.     

Adipic and malonic acid aqueous solutions: surface tensions and saturation vapor pressures

The surface tension of adipic aqueous solutions was measured as a function of temperature (T=278-313 K) and adipic acid mole fraction (X=0.000-0.003) using the Wilhelmy plate method. A parametrization fitted to these data is presented. The evaporation rates of binary water-malonic and water-adipic acid droplets were measured with a TDMA technique at different temperatures (T=293-300 K) and relative humidities (58-80%), and the saturation vapor pressures of subcooled liquid malonic and adipic acids were derived from the data using a binary evaporation model. The temperature dependence of the vapor pressures was obtained as least-squares fits to the derived vapor pressures: ln(Psat,l) (Pa)=220.2389-22634.96/T (K)-26.66767 ln T (K) for malonic acid and ln(Psat,l) (Pa)=140.6704-18230.97/T (K)-15.48011 ln T (K) for adipic acid.