Esaki diodes live and learn

We report, as the result of shelf-life tests for Esaki diodes, the observation of minute but tangible reductions in the tunnel current after the lapse of half a century. The reduction could be attributed to 0.25% widening in the tunnel path.     

Determination of bisphenol A and 10 alkylphenols in serum using SDS micelle capillary electrophoresis with gamma-cyclodextrin.

A new micelle capillary electrophoresis based on cyclodextrin micellar electrokinetic chromatography (MEKC) for the determination of bisphenol A and 10 alkylphenols in rat serum is reported. Several surfactants and dextrins were studied. Bisphenol A and alkylphenols were separated using a 50 microm x 50 cm capillary with 20 mM borate phosphate buffer (pH 8.0) containing 20 mM sodium dodecylsulfate and 5 mM gamma-cyclodextrin as carrier. The method could determine 0.6-2000 microg/mL of phenols in 100 microL serum by photometric detection at 214 nm. Using 2.0 mL serum, 1.0 ng/mL of phenols could be determined. The relative standards deviations were 6.3-7.7% at 10 microg/mL in serum. The recoveries were 91.8-93.0% with 10 microg/mL serum samples.     

A class of dual fuzzy dynamic programs

In this paper we propose a large class of fuzzy dynamic programs. By use of the notion of dual binary relation we define a dual fuzzy dynamic program in the class. We establish two duality theorems between primal and dual fuzzy dynamic programs. One is for the two-parametric recursive equations. The other is for the nonparametric. We specify maximum–minimum process and minimum–minimum process in fuzzy environment and multiplicative–multiplicative process in quasi-stochastic environment. It is shown that the duality theorems hold between primal and dual programs.     

Probe electrospray ionization of mixture solutions using metal needles with different tip conditions

Time-dependent mass spectra of mixture solutions of cytochrome c and cholesterol were measured by probe electrospray ionization (PESI) mass spectrometry and the PESI characteristics for several metal needles were investigated with different tip conditions. For a mixture solution of cytochrome c and cholesterol in 0.1% formic acid methanol/water (1/1) at a motion frequency of 1 Hz, an acupuncture needle with a sharp tip and 0.5-mm-diameter titanium and stainless-steel wire needles gave strong cytochrome c and extremely weak cholesterol ion signals. When the frequency was lowered, and the high-voltage duration increased, the titanium and stainless-steel needles provided both cytochrome c and cholesterol ion signals with high intensities well separated over time.     

Exploration of Carbon Allotropes with Four-membered Ring Structures on Quantum Chemical Potential Energy Surfaces

The existence of a new carbon allotrope family with four-membered rings as a key unit has been recently predicted with quantum chemical calculations. This family includes carbon allotropes in prism-, polymerized prism-, sheet-, tube-, and wavy-forms. An atypical bond property has been observed in this series of carbon structures, which differs from the typical sp³, sp², and sp hybridizations. The lowest energy barrier from some of the equilibrium states of the carbon structures has been determined with the SHS-ADDF (s caled-h ypersphere-s earch combined with the a nharmonic d ownward d istortion f ollowing) method within the GRRM software program package. The height of the barriers indicates that the well is deep enough for the carbon structures to exist. This class of carbon allotropes is expected to be energy-reservoirs with extra energy of 100–350 kJ mol⁻¹ per one carbon atom. This article presents the structures, energies and reactivity of the carbon allotropes with four-membered ring structures as well as the background of the findings in the context of the global exploration of potential energy surfaces. © 2018 Wiley Periodicals, Inc.