Opacity effect on extreme ultraviolet radiation from laser-produced tin plasmas

Opacity effects on extreme ultraviolet (EUV) emission from laser-produced tin (Sn) plasma have been experimentally investigated. An absorption spectrum of a uniform Sn plasma generated by thermal x rays has been measured in the EUV range (9-19 nm wavelength) for the first time. Experimental results indicate that control of the optical depth of the laser-produced Sn plasma is essential for obtaining high conversion to 13.5 nm-wavelength EUV radiation; 1.8% of the conversion efficiency was attained with the use of 2.2 ns laser pulses.     

Intermolecular cycloaddition of N-boranonitrone with alkenes

Ethyl glyoxylate O-tert-butyldimethylsilyloxime (8), on treatment with 2.2 equiv of BF3 x OEt2, generated N-boranonitrone E, which underwent intermolecular cycloaddition with alkenes 18 to afford isoxazolidines 19 in moderate to high yields. The cycloaddition of N-boranonitrone E with most of the alkenes gave 3,5-trans isoxazolidines as the major isomers via a concerted mechanism. However, in the case of 1-methylated cyclic alkenes (18j and 18l), the cycloaddition surprisingly furnished the 3,3a-cis-cycloadducts (19j and 19l) as major isomers. A possible explanation is that the reaction of 1-methylated cyclic alkenes proceeds mainly via a stepwise mechanism. This reaction of terminal alkenes is very useful for synthesis of 1,3-anti aminoalcohol derivatives by reductive cleavage of an N-O bond.     

A highly efficient enantioselective synthesis of 2-methyl chromans via four sequential palladium-catalyzed reactions

An enantioselective synthesis of substituted 2-methyl chromans was accomplished in four steps using four sequential Pd-catalyzed reactions. A study of the key palladium-catalyzed regioselective aryl ether ring formation of two different substrates was also carried out to better understand the factors which affect the selectivity of the reaction.     

Double bond cleavage reaction of silyl enol ethers using MoO2(acac)2-tBuOOH

The double bond of various silyl enol ethers is smoothly cleaved to give carbonyl compounds by an oxidizing reagent MoO₂(acac)₂-^tBuOOH.     

Change of the electron effective mass in extremely heavily doped n-type Si obtained by ion implantation and laser annealing

Infrared optical properties of extremely heavily doped n-type Si, obtained by ion implantation and laser annealing, were studied. A new relation between free carrier effective mass (m¹) and carrier concentration (10¹⁹ ?5 × 10²¹cm^-3) was obtained. The value of m¹ increases significantly with the increase of carrier concentration, when carrier concentration exceeds 10²¹cm^-3. The result is discussed in relation to the occupation of electrons in a new valley of the conduction band.     

Modelling a baseball game to optimise pitcher substitution strategies incorporating handedness of players

^** Email: hirotsu.nobuyoshi{at}jiss.naash.go.jp^*** Email: m.wright{at}lancaster.ac.uk This paper proposes a method for identifying the optimal strategyfor substituting players in a baseball game, taking into considerationthe handedness of players, which is one of the main factorsin terms of managerial decision-making for substitution. Usinga Markov chain model, we incorporate the effect of the handednessof players by introducing the concept of the defensive earnedrun average as a measure of the defensive ability of pitchersand calibrating the batting probabilities of players dependingon their handedness. We then develop a dynamic programming formulationincluding the effect of the handedness of players. This methodis illustrated using a match based on the real line-ups of theColorado Rockies and the San Francisco Giants in the NationalLeague of Major League Baseball, especially focusing on theintroduction of a relief pitcher in consideration with his handedness.