Numerical investigation of the separation of sulfur isotopes in a single gas centrifuge

Conclusions The method developed was used to analyze the separation of stable chromium isotopes (in the form CrO₂F₂) as well as some other elements in the type of centrifuge studied. It was determined that the efficiency as a function of the parameter studied in the present work is similar. Moreover, the results made it possible to determine the dependence of the separation capability on the molecular mass and physical properties of the working gases. Moscow Engineering Physics Institute. Translated from Atomnaya énergiya, Vol. 76, No. 6, pp. 491–495, June, 1994.     

Graphene‐Analogues Boron Nitride Nanosheets Confining Ionic Liquids: A High‐Performance Quasi‐Liquid Solid Electrolyte

Solid electrolytes are one of the most promising electrolyte systems for safe lithium batteries, but the low ionic conductivity of these electrolytes seriously hinders the development of efficient lithium batteries. Here, a novel class of graphene‐analogues boron nitride (g‐BN) nanosheets confining an ultrahigh concentration of ionic liquids (ILs) in an interlayer and out‐of‐layer chamber to give rise to a quasi‐liquid solid electrolyte (QLSE) is reported. The electron‐insulated g‐BN nanosheet host with a large specific surface area can confine ILs as much as 10 times of the host's weight to afford high ionic conductivity (3.85 × 10^?3 S cm^?1 at 25 °C, even 2.32 × 10^?4 S cm^?1 at ?20 °C), which is close to that of the corresponding bulk IL electrolytes. The high ionic conductivity of QLSE is attributed to the enormous absorption for ILs and the confining effect of g‐BN to form the ordered lithium ion transport channels in an interlayer and out‐of‐layer of g‐BN. Furthermore, the electrolyte displays outstanding electrochemical properties and battery performance. In principle, this work enables a wider tunability, further opening up a new field for the fabrication of the next‐generation QLSE based on layered nanomaterials in energy conversion devices.     

Defect‐Mediated Polarization Switching in Ferroelectrics and Related Materials: From Mesoscopic Mechanisms to Atomistic Control

The plethora of lattice and electronic behaviors in ferroelectric and multiferroic materials and heterostructures opens vistas into novel physical phenomena including magnetoelectric coupling and ferroelectric tunneling. The development of new classes of electronic, energy‐storage, and information‐technology devices depends critically on understanding and controlling field‐induced polarization switching. Polarization reversal is controlled by defects that determine activation energy, critical switching bias, and the selection between thermodynamically equivalent polarization states in multiaxial ferroelectrics. Understanding and controlling defect functionality in ferroelectric materials is as critical to the future of oxide electronics and solid‐state electrochemistry as defects in semiconductors are for semiconductor electronics. Here, recent advances in understanding the defect‐mediated switching mechanisms, enabled by recent advances in electron and scanning probe microscopy, are discussed. The synergy between local probes and structural methods offers a pathway to decipher deterministic polarization switching mechanisms on the level of a single atomically defined defect.     

On the formation of carbon nanostructures on the steel surface of a reactor as a result of the decomposition of hydrocarbons in the low-temperature plasma. 1. Experimental setup,determination of basic mechanisms,estimation of the production rate

Results of experimental investigations on the formation of carbon nanostructures in a reactor as a result of the decomposition of hydrocarbons in a low-temperature plasma are presented. The influence of the internal geometry of the reactor, the temperature regimes, and the relative content of a reagent and an oxidizer in the working mixture on the formation of carbon nanostructures has been investigated. It was established that ordered carbon structures are formed on the surface of a metal containing iron and nickel. Data on the production rate of the process and the content of the structured carbon in the material obtained are presented.     

Electrical Behavior of <Emphasis Type="Italic">In Situ</Emphasis> Doped Polysilicon Films as Influenced by the Dopants

The dependence of the resistivity of doped polysilicon films on fabrication conditions is studied experimentally. The films are produced from a silane-germane-diborane or a silane-germane-phosphine gas mixture, being doped with germanium in combination with boron or phosphorus, respectively. The process parameters are identified that strongly influence the resistivity and temperature coefficient of resistance of the resulting films. They are (i) the volume ratio of germane to silane, (ii) the volume ratio of silane and germane to diborane and phosphine, (iii) substrate temperature, and (iv) annealing temperature. Common and distinctive features are identified in the patterns of behavior of resistivity observed in undoped and variously doped films. It is shown that film resistivity is to a large extent determined by grain size. It is also found that increasing the temperature of deposition or annealing makes for lower film resistivity.__________Translated from Mikroelektronika, Vol. 34, No. 3, 2005, pp. 172–180.Original Russian Text Copyright © 2005 by Kovalevskii, Borisenko, Borisevich, Dolbik.     

Effects of some chelating agents on urinary copper excretion by the rat

In order to estimate the potential advantages of new chelating agents which can enhance copper excretion in the chronic copper intoxication arising in Wilson's disease, the relative ability of none chelating agents to induce the urinary excretion of copper was compared with that of D-penicillamine (DPA) and triethylenetetramine.2HCl (TRIEN), all given ip at 1 mmol/kg to male Sprague-Dawley rats. The compounds examined were as follows: tris(2-aminoethyl)-amine.3HCl (TREN), tetraethylenepentamine.5HCl (TETREN), pentaethylenehexamine.6HCl (PENTEN), 1,4,7,11-tetraazaundecane.4HCl (TAUD), 1,5,8,12-tetraazadodecane.4HCl (TADD), 1-N-benzyltriethylenetetramine.4HCl (BzTT), 4,7,10,13-tetraazatridecanoic acid.2H2SO4 (TTPA), 1,10-bis(2-pyridylmethyl)-1,4,7,10-tetraazadecane.4HCl (BPTETA), and N,N-bis(2-pyridylmethyl)-4-(aminomethyl)benzoic acid (4ABA). Of these, BzTT, TTPA, and 4ABA are new chelating agents not previously reported. The factors by which these chelating agents enhanced copper excretion over control (untreated) levels were as follows: DPA, 7.2; TREN, 1.6; TRIEN, 4.0; TETREN, 10.1; PENTEN, 7.8; TAUD, 7.8; TADD, 2.6; TTPA, 5.6; BzTT, 1.8; and 4ABA, 5.5. The results indicate that it may well be possible to develop additional chelating agents which are equal or superior to those now used in the treatment of Wilson's disease, as well as structural types whose immunological properties may be significantly different from DPA or TRIEN, the compounds currently used in the clinic for this disorder.     

A performance index for semicoherent structures

The index introduced here provides a normalized measure of the effectiveness of any semicoherent structure. We study the mathematical properties of the index and derive different axiomatic characterizations for it. Moreover, close relationships are shown to reliability functions and also to the Birnbaum structural importance measure—for which twice the performance index plays the role of potential function—that give rise to computational procedures. Some numerical examples illustrate the application of the index.