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161.
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163.
L A Vasil'eva L N Pylev V V Kiianenko A A Nikola?shvili 《Eksperimental?nai?a onkologii?a》1989,11(2):13-15
In experiments with intrapleural injections of silicon carbide whiskers (20 mg X 3, with one month interval) to random-inbred rats their carcinogenic activity close to that of chrysotile B UICC has been established. The pleural mesotheliomas were induced in 47.7 and 34.1% of rats, respectively. 相似文献
164.
Dalila Boughaci Belaïd Benhamou Habiba Drias 《Journal of Mathematical Modelling and Algorithms》2008,7(2):101-124
In this paper, both scatter search (SS) and genetic algorithms (GAs) are studied for the NP-Hard optimization variant of the satisfiability problem, namely MAX-SAT. First, we investigate a new selection strategy based on both fitness and diversity to choose individuals to participate in the reproduction phase of a genetic algorithm. The resulting algorithm is enhanced in two ways leading to two genetic algorithm variants: the first one uses a uniform crossover. The second one uses a specific crossover operator (to MAX-SAT). The crossover operator is combined with an improved stochastic local search (SLS). The crossover operator is used to identify promising regions while the stochastic local search performs an intensified search of solutions around these regions. Secondly, we propose a scatter search variant for MAX-SAT. Both the SS and the GAs implementations share the solution selection strategy, the improved SLS method and the combination operator. Experiments on several instances from MAX-SAT libraries are performed to show and compare the effectiveness of our approaches. The computational experiments show that both (SS) and (GAs) with a stochastic local search (SLS) improvement technique outperform a classical genetic algorithm (without SLS). The two metaheuristics are able of balancing search diversification and intensification which leads to good results. In general, the specific genetic algorithm with a (SLS) improvement technique and a specific combination method provides competitive results and finds solutions of a higher quality than a scatter search. 相似文献
165.
Aïssa Wade 《Annals of Global Analysis and Geometry》2008,33(3):207-217
Poisson fiber bundles are studied. We give sufficient conditions for the existence of a Dirac structure on the total space
of a Poisson fiber bundle endowed with a compatible connection. We also provide some examples.
相似文献
166.
Nikola Kompa 《Acta Analytica》2005,20(1):16-28
The basic idea of conversational contextualism is that knowledge attributions are context sensitive in that a given knowledge
attribution may be true if made in one context but false if made in another, owing to differences in the attributors’ conversational
contexts. Moreover, the context sensitivity involved is traced back to the context sensitivity of the word “know,” which,
in turn, is commonly modelled on the case either of genuine indexicals such as “I” or “here” or of comparative adjectives
such as “tall” or “rich.” But contextualism faces various problems. I argue that in order to solve these problems we need
to look for another account of the context sensitivity involved in knowledge attributions and I sketch an alternative proposal. 相似文献
167.
Souad Mokrane Laïd Makhloufi Nicolas Alonso-Vante 《Journal of Solid State Electrochemistry》2008,12(5):569-574
Conducting polypyrrole (PPy)/C (Vulcan XC-72) composite materials were synthesized by chemical polymerization method. These
materials were used as matrix to support platinum nanoparticles, which were produced by the carbonyl chemical route. For the
same catalyst loading (50 μg cm−2), it was observed that the nature of the composite strongly influences the electrochemical activity of nanoparticulated platinum
toward the oxygen reduction reaction in acid medium. The variation of the PPy/C ratio determines the so-called substrate effect
for electrocatalysis.
Dedicated to Prof. Dr. Teresa Iwasita on the occasion of her 65th birthday in recognition of her numerous contributions to
interfacial electrochemistry. 相似文献
168.
Yohann Catel Michel Degrange Loïc Le Pluart Pierre‐Jean Madec Thi‐Nhàn Pham Fei Chen Wayne D. Cook 《Journal of polymer science. Part A, Polymer chemistry》2009,47(20):5258-5271
Four new monomers, 3‐(N‐methylacrylamido)propylidenebisphosphonic acid, 3‐(N‐propyl‐acrylamido)propylidenebisphosphonic acid, 3‐(N‐hexylacrylamido)propylidenebisphosphonic acid, and 3‐(N‐octylacrylamido)propylidenebisphosphonic acid, have been synthesized in good yields and fully characterized by 1H, 13C, 31P NMR, and HRMS. The copolymerization of these monomers with N,N′‐diethyl‐1,3‐bis(acrylamido)propane (DEBAAP) has been investigated with differential scanning calorimetry. These mixtures show a higher reactivity than DEBAAP. New self‐etch dental primers, based on these acrylamide monomers, have been formulated. Dentin shear bond strength measurements have shown that primers based on these bisphosphonic acids assure a strong bond between the tooth substance and a dental composite. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5258–5271, 2009 相似文献
169.
170.
Mariem Nafti Radhouane Chakroun Chiraz Hannachi Bechir Hamrouni Habib Nouaïgui 《Analytical letters》2017,50(12):2012-2022
Hexavalent chromium Cr(VI) is a well-established carcinogen associated with lung, nasal, and sinus cancer. Cr(VI) threshold limit values in workroom air have been recently lowered. Consequently, the currently available analytical methods are insufficiently sensitive or high cost. In this paper, a simple, cost-effective, sensitive, and reproducible method using solid-phase extraction with electrothermal atomic absorption spectrometry for determination of hexavalent chromium in airborne samples is reported. The method validation included selectivity, linearity, accuracy, and precision. Interferences from other ions likely to be present in airborne samples, including trivalent chromium, were tested and selectivity was demonstrated. The detection and quantification limits were, respectively, as low as 0.1 and 0.4?µg?L?1. The linearity ranged from 0.5 to 50.0?µg?L?1, with a regression coefficients exceeding 0.998. The extraction recovery exceeded 98%. The developed method was successfully compared with a reference spectrophotometric method. The performances achieved were similar to ion chromatography and high-performance liquid chromatography approaches. The novel method was tested on airborne samples collected from the workplace. The method’s performance suggests that it may be an alternative to high-cost techniques for monitoring occupational exposure to hexavalent chromium. 相似文献