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81.
Aihara H Alston-Garnjost M Avery RE Barbaro-Galtieri A Barker AR Barnett BA Bauer DA Bay A Bengtsson H Bobbink GJ Buchanan CD Buijs A Caldwell DO Chao H Chun S Clark AR Cowan GD Crane DA Dahl OI Daoudi M Derby KA Eastman JJ Eberhard PH Edberg TK Eisner AM Enomoto R Erné FC Fairfield KH Hauptman JM Hofmann W Hylen J Kamae T Kaye HS Kenney RW Khacheryan S Kofler RR Langeveld WG Layter JG Lin WT Linde FL Loken SC Lu A Lynch GR Madaras RJ Magnuson BD Masek GE Mathis LG Matthews JA Maxfield SJ 《Physical review letters》1988,60(23):2355-2358
82.
Y Yang VO Kennedy JB Updegraph B Samas D Macikenas B Chaloux JA Miller EM Van Goethem ME Kenney 《The journal of physical chemistry. A》2012,116(34):8718-8730
Crystal structures have been determined for the three-member set of cofacial silicon phthalocyanines, ((n-C(6)H(13))(3)SiO)[SiPcO](1-3)(Si(n-C(6)H(13))(3)). The staggering angles between adjacent rings in the dimer and trimer of this set are ~16°. The interactions leading to these angles have been investigated by the atoms-in-molecules (AIM) and reduced-density-gradient (RDG) methods. The results show that long directional interactions (LDIs) are responsible for these angles. A survey of the staggering angles in various cofacial phthalocyanines described in the literature has revealed the existence of significant LDIs in a number of them. It is apparent that in many cases the ability of LDIs to dominate the forces giving rise to the staggering angles observed in cofacial phthalocyanines depends on their inter-ring separations. 相似文献
83.
T. Alexopoulos C. Allen E. W. Anderson V. Balamurali S. Banerjee P. D. Beery P. Bhat J. M. Bishop N. N. Biswas A. Bujak D. D. Carmony T. Carter P. Cole Y. Choi R. DeBonte V. DeCarlo A. R. Erwin C. Findeisen A. T. Goshaw L. J. Gutay A. S. Hirsch C. Hojvat J. R. Jennings V. P. Kenney C. S. Lindsey C. Loomis J. M. LoSecco T. McMahon A. P. McManus N. Morgan K. Nelson S. H. Oh N. T. Porile A. Rimai D. Reeves W. J. Robertson R. P. Scharenberg B. C. Stringfellow S. R. Stampke M. Thompson F. Turkot W. D. Walker C. H. Wang J. Warchol D. K. Wesson Y. Zhan 《Zeitschrift fur Physik C Particles and Fields》1995,67(3):411-416
Fermilab experiment E735 located at the CO intersection region of the $\sqrt s = 1.8$ TeV $p\bar p$ collider analysed over 900 Φ→K + K ? events. Measured were the transverse momentum spectrum, the correlation between the average transverse momentum <pt> and the charged particle multiphcityN c , as well as the probability of Φ production per charged track,N Φ /N c , versusN c . We have also made an estinate of the total inclusive cross section for Φ mesons, $\sigma (p\bar p \to \phi X) = 7.3 \pm 2.2 mb$ . 相似文献
84.
Arisaka K Auerbach LB Axelrod S Belz J Biery KA Buchholz P Chapman MD Cousins RD Diwan MV Eckhause M Ginkel JF Guss C Hancock AD Heinson AP Highland VL Hoffmann GW Horvath J Irwin GM Joyce D Kaarsberg T Kane JR Kenney CJ Kettell SH Kinnison WW Knibbe P Konigsberg J Kuang Y Lang K Lee DM Margulies J Mathiazhagan C McFarlane WK McKee RJ Melese P Milner EC Molzon WR Ouimette DA Riley PJ Ritchie JL Rubin P Sanders GH Schwartz AJ Sivertz M Slater WE Urheim J Vulcan WF Wagner DL Welsh RE Whyley RJ 《Physical review letters》1993,70(8):1049-1052
85.
Ehud Ben-Hur Marian E. Clay Eduardo F. Vicioso Antonio R. Antunez Boris D. Rihter Malcolm E. Kenney Nancy L. Oleinick 《Photochemistry and photobiology》1992,55(2):231-237
When a dilute F- solution was added to a culture of Chinese hamster cells that had been preincubated with an aluminium phthalocyanine sensitizer derived from AlPcCl, the photosensitivity of the cells was markedly reduced compared to control cells not treated with F-. Under the same treatment conditions, the reduction in [3H]thymidine incorporation into cellular DNA caused by light and this sensitizer and the production of DNA-protein crosslinks caused by light and this sensitizer were also inhibited by F-. In contrast, the killing of Chinese hamster cells, the reduction of thymidine incorporation by the cells, and the production of DNA-protein crosslinks in the cells caused by the combination of light and either Photofrin II or the silicon phthalocyanine HOSiPcOSi(CH3)2(CH2)3-N(CH3)2 were not inhibited by F-. We conclude that the aluminium phthalocyanine sensitizer used is largely or completely AlPc(OH)(H2O), that it is converted to a fluoro complex by F-, and that this compound probably is a less efficient generator of photochemical damage at a critical cellular target(s) than is AlPc(OH)(H2O). The inhibition of thymidine incorporation and DNA-protein crosslink formation indicates that the effects of F- can be expressed at intracellular sites. It is further concluded that the silicon phthalocyanine sensitizer and Photofrin II do not interact significantly with F-. 相似文献
86.
S. Dayal R. Królicki Y. Lou X. Qiu J.C. Berlin M.E. Kenney C. Burda 《Applied physics. B, Lasers and optics》2006,84(1-2):309-315
The first real-time observation of the early events during energy transfer from a photoexcited CdSe nanoparticle to an attached
phthalocyanine molecule are presented in terms of a femtosecond spectroscopic pump–probe study of the energy transfer in conjugates
of CdSe nanoparticles (NPs) and silicon phthalocyanines (Pcs) with 120 fs time resolution. Four different silicon phthalocyanines
have been conjugated to CdSe NPs. All of these have proven potential for photodynamic therapy (PDT). In such NP-Pc conjugates
efficient energy transfer (ET) from CdSe NPs to Pcs occurs upon selective photoexcitation of the NP moiety. Spectral analysis
as well as time-resolved fluorescence up-conversion measurements revealed the structure and dynamics of the investigated conjugates.
Femtosecond transient differential absorption (TDA) spectroscopy was used for the investigation of the non-radiative carrier
and ET dynamics. The formation of excitons, trapped carriers states, as well as stimulated emission was monitored in the TDA
spectra and the corresponding lifetimes of these states were recorded. The time component for energy transfer was found to
be between 15 and 35 ps. The ET efficiencies are found to be 20-70% for the four Pc conjugates, according to fluorescence
quenching experiments. Moreover, as a result of the conjugation between NP and the Pcs the photoluminescence efficiency of
the Pc moieties in the conjugates do not strictly follow the quantum yields of the bare phthalocyanines.
PACS 73.63.Bd 相似文献
87.
Anula HM Berlin JC Wu H Li YS Peng X Kenney ME Rodgers MA 《The journal of physical chemistry. A》2006,110(15):5215-5223
Eleven silicon phthalocyanines which can be grouped into two homologous series [SiPc[OSi(CH3)2(CH2)(n)N(CH3)2]2, n = 1-6 (series 1), and SiPc[OSi(CH3)2(CH2)3N((CH2)(n)H)2]2, n = 1-6 (series 2)] as well as an analogous phthalocyanine, SiPc[OSi(CH3)2(CH2)3NH2]2, were synthesized. The ground state absorption spectra, the triplet state dynamics, and singlet oxygen quantum yields of 10 of these phthalocyanines were measured. All compounds displayed similar ground state absorption spectral properties in dimethylformamide solution with single Q band maxima at 668 +/- 2 nm and B band maxima at 352 +/- 1 nm. Photoexcitation of all compounds in the B bands generated the optical absorptions of the triplet states which decayed with lifetimes in the hundreds of microseconds region. Oxygen quenching bimolecular rate constants near 2 x 10(9) M(-1) s(-1) were measured, indicating that energy transfer to oxygen was exergonic. Singlet oxygen quantum yields, phi(delta), were measured, and those phthalocyanines in which the axial ligands are terminated by dimethylamine residues at the end of alkyl chains having four or more methylene links exhibited yields near > or = 0.35. Others gave singlet oxygen quantum yields near 0.2, and still others showed singlet oxygen yields of <0.1. The reduced singlet oxygen yields are probably caused by a charge transfer quenching of the 1pi,pi* state of the phthalocyanine by interaction with the lone pair electrons on the nitrogen atoms of the amine termini. In some cases, these can approach and interact with the electronically excited pi-framework, owing to diffusive motions of the flexible oligo-methylene tether. 相似文献
88.
Reflection of plane waves from the boundary of a pre-stressed compressible elastic half-space 总被引:2,自引:0,他引:2
The effect of pre-stress on the propagation and reflection ofplane waves in an incompressible isotropic elastic half-spacehas been examined recently by the authors (Ogden & Sotiropoulos,1997). In the present paper the corresponding analysis for compressiblematerials is detailed. In the two-dimensional context consideredfor incompressible materials the (homogeneous) plane waves werenecessarily shear waves. By contrast, in the compressible contextpure shear waves can propagate only in specific directions inthe considered principal plane and, in a general direction,a quasi-shear wave may be accompanied by a quasi-longitudinalwave, as is the case in the anisotropic linear theory. The dependenceof the (in-plane) slowness section on the pre-stress (and finitedeformation) and on the choice of constitutive law is elucidated.This information is used to determine the reflection coefficientsfor reflection of either a (quasi-) shear wave or a (quasi-)longitudinal wave from the boundary of the half-space and tocharacterize the different cases which arise depending on thegeometry of the slowness section. The theoretical results are illustrated by numerical calculationsfor the range of possible types of behaviour with referenceforms of strain-energy function and different states of finitedeformation and to the question of stability of the half-space. 相似文献
89.
Toby Kenney 《Journal of Pure and Applied Algebra》2011,215(2):131-144
“The axiom of choice states that any set X of non-empty sets has a choice function—i.e. a function satisfying f(x)∈x for all x∈X. When we want to generalise this to a topos, we have to choose what we mean by non-empty, since in , the three concepts non-empty, inhabited, and injective are equivalent, so the axiom of choice can be thought of as any of the three statements made by replacing “non-empty” by one of these notions.It seems unnatural to use non-empty in an intuitionistic context, so the first interpretation to be used in topos theory was the notion based on inhabited objects. However, Diaconescu (1975) [1] showed that this interpretation implied the law of the excluded middle, and that without the law of the excluded middle, even the finite version of the axiom of choice does not hold! Nevertheless some people still view this as the most appropriate formulation of the axiom of choice in a topos.In this paper, we study the formulation based upon injective objects. We argue that it can be considered a more natural formulation of the axiom of choice in a topos, and that it does not have the undesirable consequences of the inhabited formulation. We show that if it holds for , then it holds in a wide variety of topoi, including all localic topoi. It also has some of the classical consequences of the axiom of choice, although a lot of classical results rely on both the axiom of choice and the law of the excluded middle. An additional advantage of this formulation is that it can be defined for a slightly more general class of categories than just topoi.We also examine the corresponding injective formulations of Zorn’s lemma and the well-order principle. The injective form of Zorn’s lemma is equivalent to the axiom of injective choice, and the injective well-order principle implies the axiom of injective choice. 相似文献
90.
J. Richard Hess Kevin L. Kenney Christopher T. Wright Robert Perlack Anthony Turhollow 《Cellulose (London, England)》2009,16(4):599-619
As biorefining conversion technologies become commercial, feedstock availability, supply system logistics, and biomass material
attributes are emerging as major barriers to the availability of corn stover for biorefining. While systems do exist to supply
corn stover as feedstock to biorefining facilities, stover material attributes affecting physical deconstruction, such as
densification and post-harvest material stability, challenge the cost-effectiveness of present-day feedstock logistics systems.
In addition, the material characteristics of corn stover create barriers with any supply system design in terms of equipment
capacity/efficiency, dry matter loss, and capital use efficiency. However, analysis of a conventional large square bale corn
stover feedstock supply system concludes that (1) where other agronomic factors are not limiting, corn stover can be accessed
and supplied to a biorefinery using existing bale-based technologies, (2) technologies and new supply system designs are necessary
to overcome biomass bulk density and moisture material property challenges, and (3) major opportunities to improve conventional
bale biomass feedstock supply systems include improvements in equipment efficiency and capacity and reducing biomass losses
in harvesting, collection, and storage. Finally, the backbone of an effective stover supply system design is the optimization
of intended and minimization of unintended material property changes as the corn stover passes through the individual supply
system processes from the field to the biorefinery conversion processes.
相似文献
J. Richard HessEmail: |