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ukasz Chacaga Evan B. Jochnowitz Zohra Guennoun Hongbin Ding John P. Maier 《International journal of mass spectrometry》2009,280(1-3):174
The gas-phase electronic spectrum of cyclic-B3 (D3h) radical has been remeasured in a supersonic molecular beam using a mass-selective resonant 2-color 2-photon technique, leading to a revision of previously reported spectroscopic constants. The species was prepared by ablation of a boron nitride rod in the presence of helium. Ab intio calculations on the geometries and vertical electronic excitation energies, as well as mass identification, indicate that the detected band, centered at 21848.77(2) cm−1, is the origin of the cyclic-11B3 system. A spectral fit yields the rotational constants as B″ = 1.2246(45) and C″ = 0.62131(72) cm−1 in the ground state, and B′ = 1.1914(44) and C′ = 0.61173(69) cm−1 in the excited 2 2E′ state. 相似文献
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This study describes a synthesis of symmetric and dissymmetric bis[(perfluoroalkane)‐sulfonyl]imides by the reaction of the sodium salt of perfluoroalkanesulfonamide RFSO2NH−Na+ (RF = C4F9, C6F13, C8F17) with hexamethyldisilazane and perfluoroalkanesulfonylfluoride RFSO2F (RF = C4F9, C6F13, C8F17). They are obtained, in two steps, in moderate overall yield. Moreover, this paper provides a study of their inhibition on bovine carbonic anhydrase. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:542–548, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20452 相似文献
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Guennoun Z Piétri N Couturier-Tamburelli I Aycard JP 《The journal of physical chemistry. A》2006,110(24):7738-7743
Laboratory experiments involving ultraviolet (UV) irradiation of dicyanoacetylene (C(4)N(2)) trapped in water ice at 10 K have been conducted and monitored by infrared spectroscopy (FTIR). By the support of isotopic experiments and theoretical calculations, the irradiation of a DCA/H(2)O ice mixture at lambda > 230 nm has been found to be a possible source of NH(4)(+)HCO(3)(-) (ammonium bicarbonate) and NH(4)(+)HCOO(-) (ammonium formate). These latter compounds can arise from a proton-transfer reaction between H(2)O and the CN radical, which is issued from photolyzed C(4)N(2). 相似文献
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ZAKNROU Zohra 《高等学校化学研究》2011,27(1):99-103
The authors investigated the regulation of human aquaporin 1(hAQP1) and the involvement of aquaporin 1(AQP1) in the migration of human hepatocellular carcinoma SMMC-7221 cells using RNA intereference technology. Firstly, two short hairpin RNA(shRNA) constructs in PBSU6 vector were reconstructed and their knockdown effects were identified in SMMC-7221 cells. Next, the involvement of endogenous hAQP1 in regulating the migration of SMMC-7221 cells was investigated via siRNA technology. HAQP1-shRNA can specific... 相似文献
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Lachtar Zohra Khorief Nacereddine Abdelmalek Djerourou Abdelhafid 《Structural chemistry》2020,31(1):253-261
Structural Chemistry - The enantioselectivity of the oxazaborolidine-catalysed asymmetric reduction reaction of ketimine generated from acetophenone has been investigated by transition state theory... 相似文献
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On a compact Riemannian manifold,we prove a decomposition theorem for arbitrarily bounded energy sequence of solutions of a singular elliptic equation. 相似文献
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Ilyes Jedidi Zohra Ferhat‐Hamida Geneviève Delmas 《Journal of Polymer Science.Polymer Physics》2007,45(15):1932-1949
A linear Union Carbide PE (UC) has been analyzed by nonstandard calorimetry with a common DSC calorimeter and a Setaram C80 calorimeter. Nonstandard calorimetry entails using a low rate of heating (0.5–1 K/min), a small mass (0.5–1.5 mg), and an open cell (O‐cell) instead of the standard C‐cell. Events in O‐cells overlap less and occur with a faster kinetics than in C‐cells. PE crystals are nascent, solution‐grown (S‐grown), press‐grown (P‐grown), and strained by extrusion. In Part A, the traces show that the phase‐changes in the melt, previously observed in a C80 calorimeter (slow T‐ramp) and characterized by ΔHnetwork, can be observed with a common DSC in nonstandard conditions. In Part B, the difference between the C‐ and O‐cells and the changes in the main peak enthalpy (ΔHortho) are of interest. The main result is that, in O‐cells, the value of ΔHortho around Tortho, exceeds unambiguously in certain conditions ΔHortho found for perfect orthorhombic crystals. The main endotherm contains then another contribution, namely ΔHnetwork. Crystal reorganization during the slow T‐ramp is followed in the C‐ and O‐cells on S‐grown crystals. In O‐cells, lamellar thickening observed in the slow‐ramp is more extensive. The ease of phase‐change depends on the sample history. It is as follows: strained‐part extruded > nascent > S‐grown > P‐grown. Co‐operative chain motions are more hindered in the standard C‐cells than in the O‐cells. In Part C, lower values of m succeed in bringing phase‐changes in P‐grown (O‐cells) samples. The origin of the events is discussed: three processes are thought to contribute to the phase‐changes namely, melting of strained short‐range order, activation of vibrations in the CH2 groups, and fast decay of chain orientation which occurs simultaneously with melting. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1932–1949, 2007 相似文献
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Farida Benmouna Zohra Bouabdellah-Dembahri Mustapha Benmouna 《Journal of Macromolecular Science: Physics》2013,52(7):998-1008
The process of polymer synthesis based on polymerization-induced phase separation (PIPS) is revisited from the theoretical point of view. Cahn–Hilliard–Cook theories for spinodal decomposition are adapted to describe the kinetics of phase separation and deduce the time-resolved scattering function, while the double reaction model is used to describe the kinetics of polymerization. Coupling of these two kinetics is provided by the Carother's equation relating the fraction of reacted monomers to the degree of polymerization at time t, denoted N(t). It is argued that the approach to criticality is governed by a critical parameter, χc, that is different from the usual parameter for spinodal decomposition, χs, deduced from the second derivative of the free energy. While the latter parameter depends on the reciprocal degree of polymerization N?1(t), the former one depends on its time integral. This leads to significant consequences on the phase behavior developments during the PIPS process. Hydrodynamic interactions are found to speed up the emergence of instability modes. Although the qualitative trends remain similar to those of the Rouse dynamics, important quantitative changes are found due to the long-range viscous flow effects. 相似文献
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R. Hannachi S. Boussaïdi P. Teulet G. Taieb Y. Cressault A. Gleizes Zohra Ben Lakhdar 《Applied Physics A: Materials Science & Processing》2008,92(4):933-937
A spectroscopic study of the plasma plume created by a laser beam on the surface of NaCl aqueous solution is presented. Optical
emission spectra are recorded and temporally analyzed; electron number density is determined from the Stark broadening of
the NI nitrogen line, and temperature is obtained from relative intensity of OI oxygen lines. The intensity of an atomic line
from sodium was used to quantitate its molar percentage in the Oceanic and Mediterranean sea, and calibration curves have
been constructed for concentrations ranging up to 1.5%. 相似文献