Improvement of ozone yielding rate in atmospheric pressure barrierdischarges using a time-modulated power supply

The ozone (O₃) yielding rate of a high-pressure thin-gap barrier discharge was improved using a time-modulated power supply. The maximum improvement reached more than 20% compared with a continuous-wave power supply. The rate was strongly dependent on the discharge-off time, with the optimum one corresponding to the O₂ removal time from the discharge space. Dependence of the yielding rate on the off-time was numerically calculated using O and O₃ rate equations     

Application of central differencing and low‐dissipation weights in a weighted compact nonlinear scheme

This paper proposes WCNS‐CU‐Z, a weighted compact nonlinear scheme, that incorporates adapted central difference and low‐dissipative weights together with concepts of the adaptive central‐upwind sixth‐order weighted essentially non‐oscillatory scheme (WENO‐CU) and WENO‐Z schemes. The newly developed WCNS‐CU‐Z is a high‐resolution scheme, because interpolation of this scheme employs a central stencil constructed by upwind and downwind stencils. The smoothness indicator of the downwind stencil is calculated using the entire central stencil, and the downwind stencil is stopped around the discontinuity for stability. Moreover, interpolation of the sixth‐order WCNS‐CU‐Z exhibits sufficient accuracy in the smooth region through use of low‐dissipative weights. The sixth‐order WCNS‐CU‐Zs are implemented with a robust linear difference formulation (R‐WCNS‐CU6‐Z), and the resolution and robustness of this scheme were evaluated. These evaluations showed that R‐WCNS‐CU6‐Z is capable of achieving a higher resolution than the seventh‐order classical robust weighted compact nonlinear scheme and can provide a crisp result in terms of discontinuity. Among the schemes tested, R‐WCNS‐CU6‐Z has been shown to be robust, and variable interpolation type R‐WCNS‐CU6‐Z (R‐WCNS‐CU6‐Z‐V) provides a stable computation by modifying the first‐order interpolation when negative density or negative pressure arises after nonlinear interpolation. Copyright © 2016 John Wiley & Sons, Ltd.     

Electronic processes in NO dimerization on Ag and Cu clusters: DFT and MRMP2 studies

Experimentally observed NO dimerization on Cu and Ag surfaces is surprising because binding energy of NO dimer is very small in gas phase. MRMP2, MP2 to MP4, CCSD(T), and DFT studies of NO dimerization on Ag₂ and Cu₂ clusters disclosed that the CCSD(T) method could be applied to this reaction on Ag₂ and Cu₂ unlike NO dimerization in gas phase which exhibits significantly large nondynamical electron correlation effect. Charge-transfer (CT) from Ag₂ and Cu₂ to NO moieties plays important role in N N bond formation between two NO molecules. This CT considerably decreases nondynamical correlation effect. Also, the DFT method could be applied to this NO dimerization, if appropriate DFT functional is used; all pure functionals examined here and most of the hybrid functionals underestimated the activation barrier (E_a), while only ωB97X provided E_a similar to CCSD(T)-calculated value. NO dimerization on similar Cu₂ and Cu₅ needs moderately larger E_a than those on Ag₂ and Ag₅, because frontier orbital participating in the CT exists at lower energy in Cu₂ and Cu₅ than in Ag₂ and Ag₅. The E_a decreases in the order Ag₂ >> Ag₃₈ > Ag₇ ∼ Ag₅ and the reaction energy (ΔE) is positive (endothermic) in Ag₂ but significantly negative in Ag₃₈, Ag₇, and Ag₅, indicating that various Ag clusters could be effective for NO dimerization except for Ag₂. The decreasing order of E_a and increasing order of exothermicity are attributed to increasing order of the frontier orbital energy of Ag₂ < Ag₃₈ < Ag₇ ∼ Ag₅. © 2018 Wiley Periodicals, Inc.     

Optical resolution of various amino acids using a supported liquid membrane encapsulating a surfactant-protease complex

We have encapsulated a surfactant-protease complex (the main protease used being alpha-chymotrypsin) in an organic phase of a supported liquid membrane (SLM) for the optical resolution of various amino acids. L-Isomers of amino acids were enantioselectively permeated through the SLM. The mechanism of the amino acid permeation through the SLM was considered to be as follows; an L-amino acid was enantioselectively esterified with ethanol by a surfactant-protease complex encapsulated in the SLM, and the resulting L-amino acid ethyl ester dissolved into the organic phase of the SLM and diffused across the SLM. Another surfactant-alpha-chymotrypsin complex in the receiving phase catalyzed ester hydrolysis to produce the initial L-amino acid and ethanol, which are water-soluble. Thus, the L-amino acid was selectively transported to the receiving phase through the SLM on the basis of the molecular recognition of the surfactant-protease complex in the SLM. It was found that the catalytic activity and enantioselectivity of the surfactant-protease complex governed the permeate flux of amino acids and the enantiomeric excess in the membrane separation.     

Comb-shaped poly(ethylene glycol)-modified subtilisin Carlsberg is soluble and highly active in ionic liquids

Subtilisin Carlsberg conjugated with comb-shaped poly(ethylene glycol) was solubilized in common ionic liquids without adding water, and exhibited higher transesterification activity in an ionic liquid, [Emim][Tf2N], than in organic solvents commonly used for enzymatic biotransformation.     

New anthraquinone and iridoid from the fruits of Morinda citrifolia

From the fruits of Morinda citrifolia L., one new anthraquinone, 5,15-O-dimethylmorindol, together with five known anthraquinones and one new iridoid, morindacin, together with two known iridoids, were isolated. Their structures were elucidated by analysis of spectroscopic data.     

Synthesis of cyclic dienamide using ruthenium-catalyzed ring-closing metathesis of ene-ynamide

[reaction: see text] Ring-closing metathesis of ene-ynamide using the second-generation Grubbs' catalyst produced nitrogen-containing heterocycles, which have dienamide moieties, in high yields. Diels-Alder reaction of the cyclized product and dienophile proceeded smoothly to afford a bi- or tricyclic compound.     

Spectral sets of certain unbounded functions

Summary A. Beurling introduced the concept of spectral sets of unbounded functions to study the possibility of the approximation of those by trigonometric polynomials. We consider spectral sets of unbounded functions in a certain class which contains the square of the Riemann zeta-function as a typical example.     

A PHOTON COUNTING TV CAMERA EQUIPPED WITH AN IMAGE GUIDE FOR RAPID DETECTION AND COUNTING OF SINGLE BACTERIA IN A WIDE FIELD

Abstract— We developed a photon counting TV camera system, which uses an image guide consisting of tapered optical fibers, for the rapid detection and counting of microscopic sized luminous particles in a wide field. Using a luminous bacterium as a standard, we compared this image guide-coupled TV camera to a lens-coupled TV camera by determining their light collecting powers and detection abilities for single bacteria on a membrane filter. The image guide shortened the detection time by an order of magnitude, making the photon counting TV camera a practical system for rapid counting of bacteria.