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排序方式: 共有74条查询结果,搜索用时 31 毫秒
51.
We report on what we believe is the first demonstration of single-mode polymer optical fiber with embedded electrodes. We show that the electrodes can be used to pole the dye-doped core and to electro-optically phase modulate the light in the waveguide. 相似文献
52.
53.
John H. Nelson Roy G. Garvey Ronald O. Ragsdale 《Journal of heterocyclic chemistry》1967,4(4):591-597
It is recommended that a self-consistent set of sigma constants be used to obtain linear free energy relations with pyridine 1-oxides rather than using adjusted benzoic acid sigma constants. These recommended constants are derived from the literature values of the acid dissociated constants of the protonated substituted pyridine 1-oxides. A survey and discussion of linear free energy relations using these new constants (σPyNO) is given. Comparisons of correlations using adjusted benzoic acid sigma constants and (σPyNO) are presented. 相似文献
54.
55.
The synthesis of novel N-1-alkylspirohydantoins (1-alkyl-1,3,8-triazaspiro[4.5]decanes) is reported. The key hydantoin intermediates 3 were prepared using standard hydantoin methodology. This synthesis allows for differential substitution of all three nitrogens. 相似文献
56.
Chiang CT Shores KS Freindorf M Furlani T DeLeon RL Garvey JF 《The journal of physical chemistry. A》2008,112(46):11559-11565
To understand the interaction between toluene and methanol, the chemical reactivity of [(C6H5CH3)(CH3OH) n=1-7](+) cluster ions has been investigated via tandem quadrupole mass spectrometry and through calculations. Collision Induced Dissociation (CID) experiments show that the dissociated intracluster proton transfer reaction from the toluene cation to methanol clusters, forming protonated methanol clusters, only occurs for n = 2-4. For n = 5-7, CID spectra reveal that these larger clusters have to sequentially lose methanol monomers until they reach n = 4 to initiate the deprotonation of the toluene cation. Metastable decay data indicate that for n = 3 and n = 4 (CH3OH)3H(+) is the preferred fragment ion. The calculational results reveal that both the gross proton affinity of the methanol subcluster and the structure of the cluster itself play an important role in driving this proton transfer reaction. When n = 3, the cooperative effect of the methanols in the subcluster provides the most important contribution to allow the intracluster proton transfer reaction to occur with little or no energy barrier. As n >or= 4, the methanol subcluster is able to form ring structures to stabilize the cluster structures so that direct proton transfer is not a favored process. The preferred reaction product, the (CH3OH)3H(+) cluster ion, indicates that this size-restricted reaction is driven by both the proton affinity and the enhanced stability of the resulting product. 相似文献
57.
Zhu LY Peng JC Reimer PE Awes TC Brooks ML Brown CN Bush JD Carey TA Chang TH Cooper WE Gagliardi CA Garvey GT Geesaman DF Hawker EA He XC Isenhower LD Kaplan DM Kaufman SB Klinksiek SA Koetke DD Lee DM Lee WM Leitch MJ Makins N McGaughey PL Moss JM Mueller BA Nord PM Papavassiliou V Park BK Petitt G Sadler ME Sondheim WE Stankus PW Thompson TN Towell RS Tribble RE Vasiliev MA Webb JC Willis JL Wise DK Young GR;FNAL E/NuSea Collaboration 《Physical review letters》2007,99(8):082301
We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a deuterium target. The muon angular distributions in the dilepton rest frame have been measured over the kinematic range 4.5相似文献
58.
Chiang CT Freindorf M Furlani T DeLeon RL Richard JP Garvey JF 《The journal of physical chemistry. A》2007,111(27):6068-6076
The interaction between ammonia and the benzene radical cation has been investigated by gas-phase studies of mass selected ion clusters {C(6)H(6)-(NH(3))(n=0-8)}(+) via tandem quadrupole mass spectrometry and through calculations. Experiments show a special stability for the cluster ion that contains four ammonias: {C(6)H(6)(NH(3))(4)}(+). Calculations provide evidence that the first ammonia forms a weak dative bond to the cyclohexadienyl radical cation, {C(6)H(6)-NH(3)}(+), where there is a transfer of electrons from ammonia to benzene. Additional solvating ammonia molecules form stabilizing hydrogen bonds to the ring-bound ammonia {C(6)H(6)-NH(3)}(+).(NH(3))(n), which cause cooperative changes in the structure of the cluster complex. Free ammonia is a weak hydrogen bond donor, but electron transfer from NH(3) to the benzene ring that strengthens the dative bond will increase the hydrogen acidity and the strength of the cluster hydrogen bonds to the added ammonia. A progressive "tightening" of this dative bond is observed upon addition of the first, second, and third ammonia to give a cluster stabilized by three N-(+)H x N hydrogen bonds. This shows that the energetic cost of tightening the dative bond is recovered with dividends in the formation of stable cluster hydrogen bonds. 相似文献
59.
Aguilar-Arevalo AA Bazarko AO Brice SJ Brown BC Bugel L Cao J Coney L Conrad JM Cox DC Curioni A Djurcic Z Finley DA Fleming BT Ford R Garcia FG Garvey GT Green C Green JA Hart TL Hawker E Imlay R Johnson RA Kasper P Katori T Kobilarcik T Kourbanis I Koutsoliotas S Laird EM Link JM Liu Y Liu Y Louis WC Mahn KB Marsh W Martin PS McGregor G Metcalf W Meyers PD Mills F Mills GB Monroe J Moore CD Nelson RH Nienaber P Ouedraogo S Patterson RB Perevalov D Polly CC Prebys E Raaf JL Ray H Roe BP 《Physical review letters》2007,98(23):231801
The MiniBooNE Collaboration reports first results of a search for nu e appearance in a nu mu beam. With two largely independent analyses, we observe no significant excess of events above the background for reconstructed neutrino energies above 475 MeV. The data are consistent with no oscillations within a two-neutrino appearance-only oscillation model. 相似文献
60.
Erwan Castanet Quanxiang Li Ludovic F. Dumée Christopher Garvey Rangam Rajkhowa Jin Zhang Bernard Rolfe Kevin Magniez 《Cellulose (London, England)》2016,23(6):3521-3534
Natural fibers are promising alternatives to synthetic fibers because of their sustainability, low environmental footprint and specific properties desirable for a wide range of technical engineering applications. The industrial implementation of fine grade natural bamboo fibers, including technical (100–200 microns) and elementary fibers (<30 microns) has been of increasing interest in recent times because these fibers offer a unique set of properties including high tensile strength, antibacterial and UV absorption. However to date, very little scientific effort has been devoted to fully understand the inter-correlation between their mechanical, physico-chemical, microstructural and morphological properties. In this paper, we report for the first time the structure–property relationship of elementary bamboo fibers. The impact of the inner microstructural organization of fibers (including the micro-fibrils angle) and physico-chemical factors such as the cellulose content and crystallinity index, on the tensile performance of these fibers is discussed in detail. This work also provides an insight into the application of bamboo fibers as natural and low-cost sorbent material for the removal of Cu2+ metal ions from model industrial wastewater. The metal ion adsorption properties of the fibers are correlated to surface energy analysis obtained from inverse gas chromatography. 相似文献