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951.
Denis N. Buckley Elizabeth Harvey Sung-Nee G. Chu 《Monatshefte für Chemie / Chemical Monthly》2002,20(1):785-798
Film formation on compound semiconductors under anodic conditions is discussed. The surface properties of InP electrodes were examined following anodization in an (NH4)2S electrolyte. The observation of a current peak in the cyclic voltammetric curve was attributed to selective etching of the substrate and a film formation process. AFM images of samples anodized in the sulfide solution revealed surface pitting. Thicker films formed at higher potentials exhibited extensive cracking as observed by optical and electron microscopy, and this was explicitly demonstrated to occur ex situ rather than during the electrochemical treatment. The composition of the thick film was identified as In2S3 by EDX and XPS. The measured film thickness varies linearly with the charge passed, and comparison between experimental thickness measurements and theoretical estimates for the thickness indicate a porosity of over 70%. Cracking is attributed to shrinkage during drying of the highly porous film and does not necessarily imply stress in the wet film as grown. During the growth of the thick porous film, spontaneous current oscillations have been observed. The frequency of oscillation was found to be proportional to the current density, regardless of whether the measurements were carried out during a potential sweep or at constant potential. Thus, the charge passed per oscillation remained constant. A characteristic value of approximately 0.3 C · cm−2 was measured under potential sweep conditions, and a similar value was obtained at constant potential. 相似文献
952.
Laurent Denis 《Commentarii Mathematici Helvetici》1995,70(1):235-247
Résumé Dans [P1] P. Philippon a démontré un lemme de multiplicités sur un groupe algébrique en employant des méthodes d'algèbre commutative.
On introduit ici la théorie de l'intersection pour enlever une constante 2 qui appara?ssait dans le résultat final de [P1]. 相似文献
953.
Phototoxicity of Some Bromine-Substituted Rhodamine Dyes: Synthesis, Photophysical Properties and Application as Photosensitizers 总被引:2,自引:0,他引:2
Prabir Pal Hualing Zeng Gilles Durocher Denis Girard Tiechao Li Ajay K. Gupta Richard Giasson Louise Blanchard Louis Gaboury Antonia Balassy Chantal Turmel ré Laperrière Luc Villeneuve 《Photochemistry and photobiology》1996,63(2):161-168
Abstract— The synthesis of some bromine-substituted rhodamine derivatives viz. , 4,5-dibromorhodamine methyl ester (dye 2) and 4,5-dibromorhodamine n -butyl ester (dye 3) are reported. These dyes were synthesized to promote a more efficient cancer cell photosensitizer for potential use in in vitro bone marrow purging in preparation for autologous bone marrow transplantation. Spectroscopic and photo-physical characterization of these dyes together with rhodamine 123 (dye 1) are reported in water, methanol, eth-anol and also in a microheterogeneous system, sodium dodecyl sulfate. The possible mechanism of photosensi-tization is characterized in terms of singlet oxygen efficiency of these dyes. Singlet oxygen quantum yields for bromine-substituted dyes are in the range of 0.3-0.5 depending on the solvent. For dye 1 no singlet oxygen production is found. The photodynamic actions of these dyes in different cell lines are tested. It was found that dye 2 and dye 3 are efficient photosensitizers and mediate eradication of K562, EM2, myeloid cell lines (CML) and the SMF-AI rhabdomyosarcoma line. 相似文献
954.
955.
The graphical relaxation of the Traveling Salesman Problem is the relaxation obtained by requiring that the salesman visit each city at least once instead of exactly once. This relaxation has already led to a better understanding of the Traveling Salesman polytope in Cornuéjols, Fonlupt and Naddef (1985). We show here how one can compose facet-inducing inequalities for the graphical traveling salesman polyhedron, and obtain other facet-inducing inequalities. This leads to new valid inequalities for the Symmetric Traveling Salesman polytope. This paper is the first of a series of three papers on the Symmetric Traveling Salesman polytope, the next one studies the strong relationship between that polytope and its graphical relaxation, and the last one applies all the theoretical developments of the two first papers to prove some new facet-inducing results.This work was initiated while the authors were visiting the Department of Statistics and Operations Research of New York University, and continued during several visits of the first author at IASI. 相似文献
956.
957.
958.
Mustayeen A. Khan Denis Cronier Gilles M. Bouet François Vierling 《Transition Metal Chemistry》1995,20(4):369-371
Summary A spectrophotometric study of NiII chloro complexes in the u.v.-vis. region was carried out at 25 °C and constant ionic strength of 1 mol dm–3. A matrix rank treatment method was used to identify two successive mononuclear complexes, NiCl+ and NiCl2, in the three alcohols studied viz. MeOH, EtOH and i-PrOH. The best values for the apparent overall stability constants,
j
, were calculated using a program based on the least-squares method. The log
1 and log
2 values in MeOH, EtOH and i-PrOH are 1.3 and 1.2, 1.7 and 1.8, and 1.9 and 2.2, respectively. The stability increases directly with the mol. wt. of the solvent, or decreases as a linear function of the permittivity of the pure solvent. The electronic spectra and the formation curves of the two complexes in MeOH solutions were calculated. 相似文献
959.
Mossambine (6) was obtained by a six-step reaction sequence from the indoloazepine ester 7. Radical cyclization of the tetracyclic vinyl iodide 12a provided a racemic pentacyclic ketone 16E, which could be converted to either enantiomer by condensation with (S or R)-N,S-dimethyl-S-phenylsulfoximine and selective pyrolysis of the resulting diastereomeric alcohols 18 and 19 or 20 and 21. Selective reductions of the resolved (or racemic) ketone 16E provided mossambine (6) and its hydroxy epimer 17. 相似文献
960.
In recent years, several newer designer drugs of the so-called 2C series such as 2C-D, 2C-E, 2C-P, 2C-B, 2C-I, 2C-T-2, and 2C-T-7 have entered the illicit drug market as recreational drugs. Some fatal intoxications involving 2C-T-7 have been reported. Only scarce data have been published about analyses of these substances in human blood and/or plasma. This paper describes a method for screening and simultaneous quantification of the above-mentioned compounds and their analog mescaline in human blood plasma. The analytes were analyzed by gas chromatography/mass spectrometry in the selected-ion monitoring mode, after mixed-mode solid-phase extraction (HCX) and derivatization with heptafluorobutyric anhydride. The method was fully validated according to international guidelines. Validation data for 2C-T-2 and 2C-T-7 were unacceptable. For all other analytes, the method was linear from 5 to 500 microg/L and the data for accuracy (bias) and precision (coefficient of variation) were within the acceptance limits of +/-15% and <15%, respectively (within +/-20% and <20% near the limit of quantification of 5 microg/L). 相似文献