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排序方式: 共有297条查询结果,搜索用时 93 毫秒
51.
Karim Nour 《Mathematical Logic Quarterly》2002,48(3):357-366
In this paper, we present an extension of λμ‐calculus called λμ++‐calculus which has the following properties: subject reduction, strong normalization, unicity of the representation of data and thus confluence only on data types. This calculus allows also to program the parallel‐or. 相似文献
52.
Determination of diethylhexyl phtalate in water by solid phase microextraction coupled to high performance liquid chromatography 总被引:3,自引:0,他引:3
Difficulties detected in the determination of the diethylhexylphthalate (DEHP) at trace levels by gas chromatography–mass spectrometry (GC–MS) using SPME, due to its ubiquitous distribution in the environment has been overcome and a new method for the determination of DEHP in drinking water has been proposed. The method is based on solid phase microextraction (SPME) coupled to high-performance liquid chromatography (HPLC). Detection was carried out spectrophotometrically. Calibration graph was linear in the range 10–110 μg/L with a regression coefficient of r2 = 0.998 and a detection limit of 0.6 μg/L. The relative standard deviation was 5 and 2% (n = 4) for chromatographic areas and retention times, respectively. The usefulness of the SPME–HPLC technique was confirmed. 相似文献
53.
S. El Helali K. Daoudi A. Fouzri M. Oumezzine M. Oueslati T. Tsuchiya 《Applied Physics A: Materials Science & Processing》2012,108(2):379-384
We have studied the structural and electrical properties of epitaxial La0.7Ca0.3MnO3 (LCMO) thin films prepared by metal organic deposition under different types and degrees of substrate-induced strain. 40-nm-thick films have been epitaxially grown on single-crystalline (LaAlO3)0.3?C(SrAlTaO6)0.7 (negligible tensile strain), SrTiO3 (tensile strain) and LaAlO3 (compressive strain) substrates. High-resolution X-ray diffraction and reciprocal space maps demonstrate a direct correlation between the crystalline quality and the substrate-induced strain. The electrical properties were found to be strongly dependent on the substrate used. The temperature dependence of resistivity curves was fitted using various approaches in different phases (below and above the ferromagnetic transition temperature T P). In the ferromagnetic metallic phase, ??(T) follows a T ?? power law. The obtained values of the coefficient ???(3.5?C4) indicate that the electrical transport in our films is a combination of spin wave scattering processes and electron?Cmagnon or two-magnon scattering phenomena. In the paramagnetic insulator phase, the activation energy E A and the variable range hopping characteristics (characteristic temperature T 0) were found to be strongly dependent on the strain-induced lattice mismatch between the LCMO and the substrate used. 相似文献
54.
55.
Ihssan Meskini Maria Daoudi Abdelali Kerbal Brahim Bennani Javed Sheikh Ali Parvez Loic Toupet Taibi Ben Hadda 《Journal of Saudi Chemical Society》2012,16(2):161-173
An efficient and facile method for the synthesis of novel structurally diverse β-amino dicarbonyl compounds is described by exploring the aza-Michael addition reaction in an aqueous medium as a key step. Thereby, 2-(aryl-disubstituted-amino-1-yl-methyl)-malonic acid diethyl esters were achieved in a good to excellent yields. These products were easily isolated with enough purity just by using simple recrystallization. The crystals of the compounds (17) and (24) have been obtained and studied by X-ray crystallographic analyses. 相似文献
56.
Pungente MD Jubeli E Øpstad CL Al-Kawaz M Barakat N Ibrahim T Abdul Khalique N Raju L Jones R Leopold PL Sliwka HR Partali V 《Molecules (Basel, Switzerland)》2012,17(3):3484-3500
The success of nucleic acid delivery requires the development of safe and efficient delivery vectors that overcome cellular barriers for effective transport. Herein we describe the synthesis of a series of novel, single-chain rigid cationic carotenoid lipids and a study of their preliminary in vitro siRNA delivery effectiveness and cellular toxicity. The efficiency of siRNA delivery by the single-chain lipid series was compared with that of known cationic lipid vectors, 3β-[N-(N',N'-dimethylaminoethane)carbamoyl]-cholesterol (DC-Chol) and 1,2-dimyristoyl-sn-glyceryl-3-phosphoethanolamine (EPC) as positive controls. All cationic lipids (controls and single-chain lipids) were co-formulated into liposomes with the neutral co-lipid, 1,2-dioleolyl-sn-glycerol-3-phosphoethanolamine (DOPE). Cationic lipid-siRNA complexes of varying (+/-) molar charge ratios were formulated for delivery into HR5-CL11 cells. Of the five single-chain carotenoid lipids investigated, lipids 1, 2, 3 and 5 displayed significant knockdown efficiency with HR5-CL11 cells. In addition, lipid 1 exhibited the lowest levels of cytotoxicity with cell viability greater than 80% at all (+/-) molar charge ratios studied. This novel, single-chain rigid carotenoid-based cationic lipid represents a new class of transfection vector with excellent cell tolerance, accompanied with encouraging siRNA delivery efficiency. 相似文献
57.
We study experimentally the evaporation of an aqueous NaCl solution with efflorescence formation in hydrophilic or hydrophobic
two-dimensional model porous media. The efflorescence formation only marginally affects the invasion patterns but greatly
modifies the drying kinetics compared to pure water. Two mechanisms are identified for explaining the impact of efflorescence
formation on drying kinetics. It is shown that the efflorescence contributes to increase the evaporation rate compared to
drying with pure water, a surprising result since the water activity is reduced in the presence of dissolved salt. This effect
is explained by the efflorescence liquid capillary pumping effect associated with the porous nature of the efflorescence.
Then, we identify a second phase where the efflorescence dries out and acts as a vapour diffusion barrier, leading to a dramatic
reduction of evaporation rate. 相似文献
58.
Mohammed Benzakour Mohammed Mcharfi Alain Cartier Abdelali Daoudi 《Journal of Molecular Structure》2004,710(1-3):169-174
In view of better understanding interactions of aminoacids and peptides with metallic cations, in the isolated state and in water, the model system glycylglycine–M+ (M=Li, Na) has been studied theoretically. The computations have been performed with the help of the density functional theory (DFT) and the B3LYP functional. The extended basis set was the standard 6-31++G**. In solution we used a recent model of continuum with a multicentric multipole expansion of the charge distribution. Our study shows that low energy complexes with lithium and sodium are rather similar. In the isolated state, the most stable form corresponds to a bidentate complex in which the cation interacts with two oxygen atoms, one from the terminal COOH and one from the amidic carbonyl. In solution, the coordination of the cation in the most stable form is 3, the nitrogen of the end amino group being the third ligand.
The energy range between the lowest energy structure and the highest energy one, in both cases, is slightly reduced under the electrostatic influence of the solvent. 相似文献
59.
Karim Nour 《Archive for Mathematical Logic》1997,36(6):461-473
In this paper, we present three methods to give the value of a classical integer in -calculus. The first method is an external method and gives the value and the false part of a normal classical integer. The
second method uses a new reduction rule and gives as result the corresponding Church integer. The third method is the M. Parigot's
method which uses the J.L. Krivine's storage operators.
Re?u le 4 Septembre 1995 相似文献
Re?u le 4 Septembre 1995 相似文献
60.
Aihara H Alston-Garnjost M Avery RE Barker AR Bauer DA Bay A Belcinski R Bingham HH Bloom ED Buchanan CD Caldwell DO Chao HY Chun SB Clark AR Cowan GD Crane DA Dahl OI Daoudi M Derby KA Eastman JJ Eberhard PH Edberg TK Eisner AM Erné FC Fairfield KH Fridman A Godfrey G Hauptman JM Ho C Hofmann W Kamae T Kenney RW Khacheryan S Kofler RR Lambert DJ Langeveld WG Layter JG Lin WT Linde FL Loken SC Lu A Lynch GR Lys JE Madaras RJ Magnuson BD Marsiske H Masek GE Mathis LG Maxfield SJ Miller ES 《Physical review D: Particles and fields》1991,43(1):29-33