299 research outputs found
FOURIER TRANSRORM EMISSION SPECTROSCOPY OF THE SYSTEM OF YN.
No full textAuthor Institution: Department of Chemistry, University of Arizona; Department of Chemistry, University of WaterlooThe electronic emission spectrum of YN has been observed in the 2.3-2.6 spectral region using a Fourier transform spectrometer. The bands were excited in a yurium hollow cathode lamp in the presence of a trace of molecular nitrogen. The observed bands, with origins at 3882.7625(4), 4229.0457(3), 4528. 6562(46), 4798.5145(13), 5049.4429(20) and 5281.2129(27), have been assigned as the 0-0, 1-1, 3-3, 4-4 and 5-5 vibrational bands, respectively, of the electronic transition. The principal equilibrium constants for the ground state obtained from this analysis are {\AA} and the corresponding excited state values are and {\AA}. This work represents the first observation of the YN molecule
Integral representation of Markov systems and the existence of adjoined functions for Haar spaces
No full textAbstractLet A be a set of real numbers, and let Yn: = {y0,…, yn} be a C̆ebys̆ev system on A. Assume, moreover, that if inf A or sup A belongs to A, then it is a point of accumulation of A at which all yj are continuous. We find necessary and sufficient conditions for the existence of a function yn + 1 such that also {y0,…, yn, yn + 1} is a C̆ebys̆ev system on A. This theorem generalizes earlier results of Zielke and of the author. The proof is based on an integral representation of Markov systems that slightly extends a previous result of Zielke
Arylchlorocarbenes in the synthesis of heterocycles containing two nitrogen atoms
No full textSubstituted pyrazoles and pyrrolo[1,2-c]pyrimidines were prepared from the reaction of arylchlorocarbenes with 1,2-diazabuta-1,3-dienes and 4-vinylpyrimidines, respectively.PT: J; CR: ATTANASI A, 1998, J ORG CHEM, V63, P9880 ATTANASI OA, 1977, SYNLETT, P1128 ATTANASI OA, 1999, TETRAHEDRON LETT, V40, P3891 BONINI BF, 1981, J CHEM SOC P1, P2322 BONNEAU R, 1999, J PHOTOCH PHOTOBIO A, V126, P31 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 KUEHNE ME, 1964, J ORG CHEM, V29, P1582 LIU MTH, 1994, INT J CHEM KINET, V26, P1179 MAIBORODA DA, 1997, J ORG CHEM, V62, P7100 MINGUEZ JM, 1996, J ORG CHEM, V61, P4655 MOYANO EL, 1998, J ORG CHEM, V63, P8188 OVERBERGER CG, 1954, J AM CHEM SOC, V76, P1879 PERKAMPUS HH, 1972, TETRAHEDRON, V28, P2099 ROMASHIN YN, 1999, CHEM COMMUN 0307, P447 ROMASHIN YN, 1999, TETRAHEDRON LETT, V40, P7163 WONG JL, 1965, J ORG CHEM, V30, P2398; NR: 16; TC: 6; J9: CHEM COMMUN; PG: 2; GA: 324XFSource type: Electronic(1
On a generalization of a conjecture of Grosswald
No full textWe generalize a conjecture of Grosswald, now a theorem due to Filaseta and Trifonov, stating that the Bessel polynomials, denoted by yn(x), have the associated Galois group Sn over the rationals for each n. We consider generalized Bessel polynomials yn,β(x) which contain interesting families of polynomials whose discriminants are nonzero rational squares. We show that the Galois group associated with yn,β(x) always contains An if β≥0 and n sufficiently large. For β<0 the Galois group almost always contains An. It is further shown that for β<−2, under the hypothesis of the abc conjecture, the Galois group of yn,β(x) contains An for all sufficiently large n. Using these results, an earlier work of Filaseta, Finch and Leidy and the first author concerning the discriminants of yn,β(x), we are able to explicitly describe the instances where the Galois group associated with yn,β(x) is An for all sufficiently large n depending on
The Diwedd/End Garden: a garden for the end of things
No full textThis paper investigates the fragmented nature of the Diwedd Garden—a guerrilla garden the author has cultivated from waste and fly-tipped materials on a forgotten plot overlooking Swansea Bay, South Wales. Situated on a liminal hillside alleyway, this assemblage-based practice explores how geographers might adopt ‘broken world thinking’ (Jackson 2014: 221) to engage creatively and critically with the production of urban space. By treating discarded fragments as both the residue and the raw material of regeneration, this paper considers how such acts of reclamation can seed new imaginaries of hope. Over a year, the author helped gather and repurpose what Haraway (2016: 57) calls the ‘excrement of the Capitolocene,’ composting it—quite literally—like a ‘mad gardener’. In doing so, this creative contribution reflects on Latour’s (2004: 246) proposition that ‘the critic is not the one who debunks, but the one who assembles,’ suggesting that creative, material engagement offers alternative, embodied ways of knowing and relating within spatial theory.
Mae'r papur hwn yn ymchwilio i natur dameidiog Gardd Diwedd—gardd guerrilla y mae'r awdur wedi'i meithrin o wastraff a deunyddiau sydd wedi cael eu tipio'n anghyfreithlon ar ddarn o dir sydd wedi mynd yn angof ac yn edrych dros Fae Abertawe. Ar lwybr ar ochr bryn, mae'r ymchwil hon sy'n seiliedig ar ddull cydosod yn mynd i’r afael â sut y gallai daearyddwyr fabwysiadu 'broken world thinking' (Jackson 2014: 221) i ymwneud yn greadigol ac yn feirniadol â chreu gofod trefol. Drwy drin darnau a luchiwyd yn weddillion ac yn ddeunydd crai adfywio, mae'r papur hwn yn ystyried sut y gall gweithredoedd adfer o'r fath ddychmygu gobaith ar ei newydd wedd. Dros gyfnod o flwyddyn, roedd yr awdur wedi helpu i gasglu ac ailddefnyddio'r hyn y mae Haraway (2016: 57) yn ei alw’n 'excrement of the Capitolocene,' gan ei gompostio—yn llythrennol—fel 'garddwr gwallgof'. Wrth wneud hynny, mae'r cyfraniad creadigol hwn yn myfyrio ar gynnig Latour (2004: 246) 'the critic is not the one who debunks, but the one who assembles,' gan awgrymu bod ymwneud yn greadigol ac yn faterol yn cynnig ffyrdd diriaethol a gwahanol o wybod a pherthnasu ym maes theori ofodol
Parallel Parsing of Arithmetic Expressions
No full textParallel algorithms for parsing expressions on mesh, shuffle, cube, and cube-connected cycle parallel computers are presented. With n processors, it requires time on the mesh-connected model and time on others. For the mesh-connected computer, the author uses a wrap-around row-major ordering. For the shuffle computer, he uses an extra connection between adjacent processors, and thus four connections per processor are require
The impact of information sharing in a two-level supply chain with multiple retailers
No full textAuthor name used in this publication: T. C. E. Cheng2004-2005 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishedGreen (AAM
Weierstrass integrability for a class of differential systems
No full textAgraïments: FEDER/UNAB10-4E-378. The second author has been supported by FCT (grant PTDC/MAT/117106/2010 and through CAMGSD).We characterize the differential equations of the form x' = y, y' = an(x)yn + an−1(x)yn−1 + · · · + a1(x)y + a0(x), n ≥ 2, an(0) ̸= 0, where aj (x) are meromorphic functions in the variable x for j = 0, . . . , n that admits either a Weierstrass first integral or a Weierstrass inverse integrating factor
On the Cauchy-Schwarz Inequality
No full textAbstractWe prove that the inequality∑k=1nxkyk2≤∑k=1nyk∑k=1nα+βkx2kyk∗holds for all natural numbersnand for all real numbersxkandyk(k=1,…,n) with0<x1≤x2/2≤···≤xn/nand0<yn≤yn−1≤···≤y1,if and only ifα≥3/4andβ≥1−α.Inequality (∗) with α=3/4 and β=1/4 refines results given by Liu Zheng (J. Math. Anal. Appl.218(1998), 13–21) and the author (J. Math. Anal. Appl.168(1992), 596–604)
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