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131.
Macrocyclic inhibitors of the NS3 protease as potential therapeutic agents of hepatitis C virus infection 总被引:3,自引:0,他引:3
132.
133.
Jackson YA Rajagopal D Bendolph J Guillory M Lakshmikantham MV Yang J Cava MP 《Organic letters》2003,5(11):1883-1885
[reaction: see text] The preparation of 1,3,5,7-tetramethyl-4,8-dihydrobenzo[1,2-c:4,5-c']dithiophene-4,8-dione and its conversion to the corresponding mono- and dithione are described. 相似文献
134.
Hopkins JM Bowdridge M Robertson KN Cameron TS Jenkins HA Clyburne JA 《The Journal of organic chemistry》2001,66(17):5713-5716
Reactions of the nucleophilic carbene 1,3-dimesityl-imidazol-2-ylidene (1) with diazofluorene, diphenyldiazomethane, and azidotrimethylsilane were examined. Specifically, carbene 1 reacts with diazofluorene and diphenyldiazomethane to give addition products (azines: 3 and 4, respectively). Compounds 3 and 4 were further characterized in the solid-state by single-crystal X-ray crystallographic studies. [3 (a = 9.7936(6) A, b = 10.0529(7) A, c = 16.251(1) A, alpha = 75.765(1) degrees, beta = 79.711(1) degrees, gamma = 64.321(1) degrees, Z = 2, space group P1); 4 (a = 11.681(3) A, b = 11.861(4) A, c = 21.186(3) A, alpha = 90 degrees, beta = 97.05(2) degrees, gamma = 90 degrees, Z = 4, space group P2(1)/n)]. The structural parameters of 3 and 4 are discussed with reference to previously characterized symmetrical and unsymmetrical azines. Structural data suggest that charge separation is possible in 3. 相似文献
135.
N. S. Kelsall C. E. Svensson S. Fischer D. E. Appelbe R. A. E. Austin D. P. Balamuth G. C. Ball J. A. Cameron M. P. Carpenter R. M. Clark M. Cromaz M. A. Deleplanque R. M. Diamond P. Fallon D. F. Hodgson R. V. F. Janssens D. G. Jenkins G. J. Lane C. J. Lister A. O. Macchiavelli C. D. O’Leary D. G. Sarantities F. S. Stephens D. C. Schmidt D. Seweryniak K. Vetter J. C. Waddington R. Wadsworth D. Ward A. N. Wilson A. V. Afanasjev S. Frauendorf I. Ragnarsson 《The European Physical Journal A - Hadrons and Nuclei》2003,20(1):131-132
High-spin states have been studied in 72Kr and 72Br using the 40Ca + 40Ca and 36Ar + 40Ca reactions at 164 and 145 MeV, respectively. The properties and configurations of the high-spin bands observed have been interpreted using unpaired cranked Nilsson-Strutinsky (CNS), and for 72Kr, paired cranked relativistic Hartree-Bogoliubov (CRHB) calculations. In 72Kr a new band has been identified that has the properties expected for the doubly aligned S-band configuration. In 72Br the previously known bands have been extended to higher spin. This has lead to a re-interpretation of the configurations.Received: 31 October 2002, Published online: 24 February 2004PACS:
21.10.Re Collective levels - 23.20.Lv
transitions and level energies - 27.50. + e
相似文献
136.
Anomalous pulse-width narrowing with first-order compensation of polarization mode dispersion 总被引:2,自引:0,他引:2
We present analytical and experimental results to demonstrate the narrowing of pulses transmitted through optical fibers, with polarization mode dispersion compensated for to first order in frequency. The compensation technique splits the optical signal at the fiber output into polarization components that are aligned with the output principal states of polarization, and only one of the two components is subsequently detected. It is shown that it is possible with this compensation technique to have output pulses that are narrower than the input pulses. Pulse narrowing can also be found when the optical signal is split into orthogonal polarization components that are not principal states of polarization. 相似文献
137.
Ji-Won Moon Lucas W. Yeary Adam J. Rondinone Claudia J. Rawn Melanie J. Kirkham Yul Roh Lonnie J. Love Tommy J. Phelps 《Journal of magnetism and magnetic materials》2007
The magnetic susceptibility (κRT) and saturation magnetization (MS) of microbially synthesized magnetites were systematically examined. Transition metal (Cr, Mn, Co, Ni and Zn)- and lanthanide (Nd, Gd, Tb, Ho and Er)-substituted magnetites were microbially synthesized by the incubation of transition metal (TM)- and lanthanide (L)-mixed magnetite precursors with either thermophilic (TOR-39) or psychrotolerant (PV-4) metal-reducing bacteria (MRB). Zinc incorporated congruently into both the precursor and substituted magnetite, while Ni and Er predominantly did not. Microbially synthesized Mn- and Zn-substituted magnetites had higher κRT than pure biomagnetite depending on bacterial species and they exhibited a maximum κRT at 0.2 cationic mole fraction (CMF). Other TMs’ substitution linearly decreased the κRT with increasing substitution amount. Based on the MS values of TM- and L-substituted magnetite at 0.1 and 0.02 CMF, respectively, Zn (90.7 emu/g for TOR-39 and 93.2 emu/g for PV-4)- and Mn (88.3 emu/g by PV-4)-substituted magnetite exhibited higher MS than standard chemical magnetite (84.7 emu/g) or pure biomagnetite without metal substitution (76.6 emu/g for TOR-39 and 80.3 emu/g for PV-4). Lanthanides tended to decrease MS, with Gd- and Ho-substituted magnetites having the highest magnetization. The higher magnetization of microbially synthesized TM-substituted magnetites by the psychrotroph, PV-4 may be explained by the magnetite formation taking place at low temperatures slowing mechanics, which may alter the magnetic properties compared to the thermophile, through suppression of the random distribution of substituted cations. 相似文献
138.
Melanie David Wilson Agerico Diño Hiroshi Nakanishi Naoki Ando 《Surface science》2007,601(22):5241-5245
The adhesion strength of polybutylene terephthalate (PBT) on aluminum was investigated using density functional theory-based total energy calculations. Aluminum atom was connected to a PBT monomer at different orientations and total energies were calculated in order to determine the most stable orientation. The energy differences showed that the Al oriented at 180° with the ester group of the monomer bonded strongly. Using this orientation, the PBT monomer-adhesion on aluminum surface and the aluminum atom adhesion on PBT bulk were also investigated. 相似文献
139.
Kazuki Fukushima Olivier Coulembier Julien M. Lecuyer Hamid A. Almegren Abdullah M. Alabdulrahman Fares D. Alsewailem Melanie A. Mcneil Philippe Dubois Robert M. Waymouth Hans W. Horn Julia E. Rice James L. Hedrick 《Journal of polymer science. Part A, Polymer chemistry》2011,49(5):1273-1281
We describe the organocatalytic depolymerization of poly(ethylene terephthalate) (PET), using a commercially available guanidine catalyst, 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD). Postconsumer PET beverage bottles were used and processed with 1.0 mol % (0.7 wt %) of TBD and excess amount of ethylene glycol (EG) at 190 °C for 3.5 hours under atmospheric pressure to give bis(2‐hydroxyethyl) terephthalate (BHET) in 78% isolated yield. The catalyst efficiency was comparable to other metal acetate/alkoxide catalysts that are commonly used for depolymerization of PET. The BHET content in the glycolysis product was subject to the reagent loading. This catalyst influenced the rate of the depolymerization as well as the effective process temperature. We also demonstrated the recycling of the catalyst and the excess EG for more than 5 cycles. Computational and experimental studies showed that both TBD and EG activate PET through hydrogen bond formation/activation to facilitate this reaction. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
140.
A. Cameron Church James H. Pawlow Kenneth B. Wagener 《Journal of organometallic chemistry》2001,620(1-2)
Various nucleophiles were reacted with the substrate di-n-hexyldichlorosilane as model reactions for the substitution of two geminal Si---Cl bonds on polymer backbone repeat units. The reactants examined were chosen on the basis of steric bulk, electronic factors, and resulting stability of the product. Linear and branched alcohol nucleophiles used in conjunction with an amine proton acceptor produced disubstituted products in moderate yields, whereas bulkier reagents substituted only one silicon---chlorine bond. Due to their vastly increased nucleophilicity, alkyllithium reagents were found to have increased activity and were found to produce very high yields. 相似文献