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81.
Kruhlak RJ Wong GK Chen JS Murdoch SG Leonhardt R Harvey JD Joly NY Knight JC 《Optics letters》2006,31(10):1379-1381
Polarization modulation instability (PMI) in birefringent photonic crystal fibers has been observed in the normal dispersion regime with a frequency shift of 64 THz between the generated frequencies and the pump frequency. The generated sidebands are orthogonally polarized to the pump. From the observed PMI frequency shift and the measured dispersion, we determined the phase birefringence to be 5.3 x 10(-5) at a pump wavelength of 647.1 nm. This birefringence was used to estimate the PMI gain as a function of pump wavelength. Four-wave mixing experiments in both the normal and the anomalous dispersion regimes generated PMI frequency shifts that show good agreement with the predicted values over a 70 THz range. These results could lead to amplifiers and oscillators based on PMI. 相似文献
82.
Using cross-correlation frequency-resolved optical gating, we observe the phase-sensitive resonance in the interaction of a soliton with a continuous wave in a photonic crystal fiber. This interaction strongly depends on the difference in the phase velocities of the orthogonally polarized fiber modes and leads to generation of a new spectral peak. The spectral and temporal structure of this signal is revealed in our measurements, which are supported by analytical theory and numerical simulations. 相似文献
83.
Fuctionalization of Linear and Angular Phenothiazine and Phenoxazine Ring Systems via Pd(0)/XPhos Mediated Suzuki‐Miyaura Cross‐coupling Reactions 下载免费PDF全文
Efeturi A. Onoabedje Uchechukwu C. Okoro David W. Knight Amitabha Sarkar 《Journal of heterocyclic chemistry》2016,53(6):1787-1794
Chloro‐substituted phenothiazines and phenoxazines were successfully derivatized with phenylboronic and styrylboronic acids using Suzuki–Miyaura cross‐coupling reaction catalyzed by Pd(0)/XPhos for the first time in good yields. The protocol employed 4 mol% Pd and 7 mol% XPhos with K3PO4 in acetonitrile at 80°C. The reaction condition is compatible with carbonyl and unprotected N–H groups in substrates. Structural assignments were established by combined spectroscopic (UV, IR, 1H, and 13C NMR), MS, and elemental analytical data. 相似文献
84.
Saad FA Buurma NJ Amoroso AJ Knight JC Kariuki BM 《Dalton transactions (Cambridge, England : 2003)》2012,41(15):4608-4617
The synthesis of a thiourea substituted derivative of tris(pyridyl-2-methyl)amine (TPA) is reported. Two of the three pyridine rings are substituted in the 6-position with benzoylthiourea groups. These thiourea groups undergo intramolecular hydrogen bonding to form six-membered rings which leaves one N-H group available to form hydrogen bonds with other molecules. This reports details how the complexation of this new ligand with transition metal ions yields complexes with differing geometries. Seven co-ordinate Mn(II) and Cd(II), six co-ordinate Ni(II) and five co-ordinate Co(II), Cu(II) and Zn(II) complexes have been isolated. 相似文献
85.
Long V. Dinh Douglas A. Knight Mark Paskevicius Craig E. Buckley Ragaiy Zidan 《Applied Physics A: Materials Science & Processing》2012,107(1):173-181
Many of the current synthesis methods for aluminum hydride (alane—AlH3) involve reacting AlCl3 and LiAlH4 in solvents. The reaction requires the formation of an alane adduct such as AlH3⋅[(C2H5)2O] prior to obtaining crystallized stable α-AlH3. This process requires several hours of pumping in a vacuum system to remove the ether and convert the alane etherate into
stable α-alane. This crystallization process is both costly and hazardous because a large amount of highly flammable material (e.g.
ether) is removed by vacuum pumps over several hours. Conversely, the work presented herein describes novel methods to synthesize
adduct-free alane. It is demonstrated here that AlH3 can form by mixing AlCl3 and LiAlH4 in the solid state and heating to 75∘C; only α-AlH3 was obtained. The α-AlH3 product can be washed with minimal solvents leading to zero formation of alane adducts. In addition, the unwanted LiCl by-product
is also removed during the solvent wash, resulting in halide-free α-alane. Although simply mixing and heating the reactants led to a 40% yield of alane, having the reactants compacted and mechanically
pressed while heating increases the yield to 60% crystalline α-AlH3. 相似文献
86.
Trammell SA Nita R Moore M Zabetakis D Chang E Knight DA 《Chemical communications (Cambridge, England)》2012,48(34):4121-4123
Using a low power green laser, we have demonstrated a rate acceleration of ~2-fold for the hydrolysis of methyl parathion by irradiating the plasmon absorption band of Au nanoparticles capped with a Cu(bpy) catalyst. 相似文献
87.
Karácsony O Deschamps JR Trammell SA Nita R Knight DA 《Molecules (Basel, Switzerland)》2012,17(5):5724-5732
The synthesis of a new 2,2'-bipyridyl functionalized oligovinylenephenylene (OVP-5) containing a methyl protected thiol using Heck coupling and the Horner-Wadsworth-Emmons reaction and is described. A key step involving a diisopropylcarbodiimide promoted dehydration of a stable β-hydroxyphosphonate intermediate was identified. The structure of precursor E-(4-(4-bromostyryl)phenyl)(methyl)sulfane was determined using X-ray crystallography. 相似文献
88.
Keith Knight 《Extremes》2001,4(2):87-103
Smith (1994) proposes estimation in linear regression models with non-negative errors by maximizing the sum of fitted values subject to the constraint that the fitted values can be no larger than the corresponding response value. In this paper, we consider the limiting distribution of these estimators under very general conditions. Some extensions to local polynomial estimation are also considered. 相似文献
89.
P.L. Knight 《Physics letters. A》1977,61(1):25-26
Long-time deviations from the exponential decay law in atomic spontaneous emission are demonstrated to be unusually sensitive to the form of the interaction Hamiltonian used to describe the decay. 相似文献
90.
Herrmann J Griebner U Zhavoronkov N Husakou A Nickel D Knight JC Wadsworth WJ Russell PS Korn G 《Physical review letters》2002,88(17):173901
We report on an experimental study of supercontinuum generation in photonic crystal fibers with low-intensity femtosecond pulses, which provides evidence for a novel spectral broadening mechanism. The observed results agree with our theoretical calculations carried out without making the slowly varying envelope approximation. Peculiarities of the measured spectra and their theoretical explanation demonstrate that the reason for the white-light generation in photonic crystal fibers is fission of higher-order solitons into redshifted fundamental solitons and blueshifted nonsolitonic radiation. 相似文献