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排序方式: 共有272条查询结果,搜索用时 31 毫秒
31.
M. Zahar A. Malki M. Bozin P. Wagner F. Rami J. P. Coffin G. Guillaume F. Jundt P. Fintz B. Rastegar D. Rebreyend F. Merchez J. Mistretta S. Kox 《Zeitschrift für Physik A Hadrons and Nuclei》1991,339(4):465-473
Protons, deuterons, tritons,α-particles and Li have been studied in coincidence with evaporation residues produced at low impact parameter for the40Ar(1100 MeV)+13C reaction. Experimental characteristics of the light particle — heavy residue correlations, and among them an effect of left-right asymmetry, are analyzed and discussed in some detail on the basis of Monte Carlo simulations. This reaction appears to be governed by an incomplete fusion process. Due to transverse emission of preequilibrium particles, the compound nuclei associated with light-particle-evaporation-residue coincidence events recoil at a non-zero degree lab. angle with some dispersion around this direction. When these effects are introduced into statistical decay calculations, it is then possible to reproduce various experimental results and to understand features like the asymmetry effect. Discrimination of light particles of preequilibrium and of evaporative origin appears possible. 相似文献
32.
Manef Chtourou Rami Abdelhdi Mohamed Hdi Frikha Mahmoud Trabelsi 《Ultrasonics sonochemistry》2010,17(1):246-249
This paper presents a novel solvent free method of synthesis of trans-chalcones. The method was based on ultrasound irradiation of the reagents (aryl methyl ketones and aryl aldehydes) in presence of commercial acid-montmorillonites as catalysts. The trans-chalcones were synthesized in high yields (85–95%) and excellent selectivity in a short reaction time. 相似文献
33.
Rami Al-Oweini 《Applied Surface Science》2010,257(1):276-281
We report the surface characterization by nitrogen adsorption-desorption technique of organically surface-modified silica aerogels. These solids were prepared through a sol-gel process from various combinations of silicon precursors and co-precursors with the aim of obtaining identically modified materials. The silicon precursors are based on four identical hydrolysable alkoxy groups (methoxy or ethoxy) whereas one of the alkoxy groups in the co-precursors is substituted by a non-hydrolysable alkyl group (methyl, ethyl, n-propyl, iso-butyl, n-octyl, vinyl or phenyl). Obtained alcogels were dried under carbon dioxide supercritical conditions and their specific surface area, pore volume, mesoporosity and pore size distribution were investigated. Mesoporous materials exhibiting high specific surface areas and total pore volumes were obtained, revealing a decreasing porosity along with the use of co-precursors having larger side chains. 相似文献
34.
With the advent of microservice-based software architectures, an increasing number of modern cloud environments and enterprises use operating system level virtualization, which is often referred to as container infrastructures. Docker Swarm is one of the most popular container orchestration infrastructures, providing high availability and fault tolerance. Occasionally, discovered container escape vulnerabilities allow adversaries to execute code on the host operating system and operate within the cloud infrastructure. We show that Docker Swarm is currently not secured against misbehaving manager nodes. This allows a high impact, high probability privilege escalation attack, which we refer to as leadership hijacking, the possibility of which is neglected by the current cloud security literature. Cloud lateral movement and defense evasion payloads allow an adversary to leverage the Docker Swarm functionality to control each and every host in the underlying cluster. We demonstrate an end-to-end attack, in which an adversary with access to an application running on the cluster achieves full control of the cluster. To reduce the probability of a successful high impact attack, container orchestration infrastructures must reduce the trust level of participating nodes and, in particular, incorporate adversary immune leader election algorithms. 相似文献
35.
The reprecipitation method was applied to Coumarin 6. A concentrated solution of the dye in acetone was mixed at room temperature with a large volume of water, and microcrystals rapidly appeared in the medium. Their size and shape were visualized by fluorescence microscopy, as well as by transmission electron microscopy. The absorption and fluorescence properties were studied on the suspensions and compared with those of the dissolved dye. This study is aimed at clarifying the influence of the reprecipitation process upon the fluorescence properties of the dye in the solid state. 相似文献
36.
Avula Krishna Kumari Vemulapati Hanuman Reddy Guda Mallikarjuna Reddy Yellala Venkata Rami Reddy Suddala Leelavathi 《Journal of heterocyclic chemistry》2019,56(5):1661-1666
In an effort for development of innovative biologically active agents, a sequence of 1,4‐dihydropyridine analogues was synthesized through the green synthetic method. In addition, all compounds were evaluated for their cytotoxic activities against three human cancer cell lines and mouse melanoma and figured out the most active compounds. Besides, promoter reusability, easy handling of the chemical reagent, simple reaction process, time minimization, ethanol–water solvent compatibility, and cost reduction reagent are key tools for this fruitful path. Thus, these examinations recommended that dihydropyridine and their derivatives are motivating moieties for the discovery of new anticancer drugs. 相似文献
37.
Accelerated D-Dimensional Compactified Universe in Gauss--Bonnet--Dilatonic Scalar Gravity from D-Brane/M-Theory 下载免费PDF全文
EL-NABULSI Ahmad Rami 《中国物理快报》2008,25(8):2785-2788
We discuss a particular d-dimensional Gauss- Ronnet-dilatonie universe compactified on S^1 motivated from Mtheory. We examine the time-evolution of the dynamical equations where many interesting consequences are revealed and discussed in some details. Under reasonable conditions, the discussed model can provide a mechanism to realize, in higher-dimensions (d 〉 4), the accelerated expansion of the universe in the presence of dark energy, without the presence of phantom energy and without the contraction of some internal dimension. 相似文献
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Synthesis of novel 3-ary1-5-(3,5-dimethylisoxazol-4-y1)-2,3,5,6-tetrahydrobenzo[g][1,3,5]oxadiazocine-4-thiones 5 has been accomplished from 3,5-dimethylisoxazol-4-amine I by condensation with salicylaldehydes, followed by reduction, treatment with aryl isothiocyanates and subsequent smooth ring closure via acetal formation in the presence of formaldehyde. 相似文献