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151.
Mohammad Hossein Tavakoli Hossein KarbaschiFeridoun Samavat Ebrahim Mohammadi-Manesh 《Journal of Crystal Growth》2010,312(21):3198-3203
A set of 2D finite element numerical simulation of induction heating process for an oxide Czochralski crystal growth system has been made for a range of f=1–100 kHz applied frequency of driving current. It was shown that the frequency selection has a marked effect in all basic induction phenomena, including electromagnetic field distribution, skin depth, coil efficiency, and intensity and structure of heating in the growth setup. 相似文献
152.
Ali Maghzi Ali Mohebbi Riyaz Kharrat Mohammad Hossein Ghazanfari 《Transport in Porous Media》2011,87(3):653-664
It is well known that the oil recovery is affected by wettability of porous medium; however, the role of nanoparticles on
wettability alteration of medium surfaces has remained a topic of debate in the literature. Furthermore, there is a little
information of the way dispersed silica nanoparticles affect the oil recovery efficiency during polymer flooding, especially,
when heavy oil is used. In this study, a series of injection experiments were performed in a five-spot glass micromodel after
saturation with the heavy oil. Polyacrylamide solution and dispersed silica nanoparticles in polyacrylamide (DSNP) solution
were used as injected fluids. The oil recovery as well as fluid distribution in the pores and throats was measured with analysis
of continuously provided pictures during the experiments. Sessile drop method was used for measuring the contact angles of
the glass surface at different states of wettability after coating by heavy oil, distilled water, dispersed silica nanoparticles
in water (DSNW), polyacrylamide solution, and DSNP solution. The results showed that the silica nanoparticles caused enhanced
oil recovery during polymer flooding by a factor of 10%. The distribution of DSNP solution during flooding tests in pores
and throats showed strong water-wetting of the medium after flooding with this solution. The results of sessile drop experiments
showed that coating with heavy oil, could make an oil-wet surface. Coating with distilled water and polymer solution could
partially alter the wettability of surface to water-wet and coating with DSNW and DSNP could make a strongly water-wet surface. 相似文献
153.
154.
155.
The isomorphic substitution of boron into ZSM‐5 zeolite under static hydrothermal condition was investigated. Evaluation of hydrothermal synthesis of BZSM‐5 was performed by treating the synthesis mixture by different aging processes, namely, ultrasonic, static, stirring, and microwave‐assisted aging prior to the conventional hydrothermal treatment. The synthetic processes with different techniques of aging prior to the onset of conventional hydrothermal crystallization were compared with a process without any prior aging. The obtained results showed that the ultrasonic and microwave assisted aging shortened the crystallization time and altered the crystal size and the morphology of the obtained products. The characteristics of the synthesized products were obtained by FT‐IR spectroscopic, XRD and SEM techniques. 相似文献
156.
Majid M. Heravi Samaheh Sadjadi Sodeh Sadjadi Hossein A. Oskooie Fatemeh F. Bamoharram 《Ultrasonics sonochemistry》2009,16(6):718-720
Bis(indolyl)alkanes have been synthesised in excellent yields in the presence of catalytic amount of silica-supported Preyssler nano particles as green, reusable and efficient catalyst under ultra sonic irradiation. 相似文献
157.
Partovi MH 《Physical review letters》2002,89(14):144101
A Hamilton-Jacobi formulation of the Lyapunov spectrum and Kolmogorov-Sinai (KS) entropy is developed. It is numerically efficient and reveals a close relation between the KS invariant and the classical action. This formulation is extended to the quantum domain using the Madelung-Bohm orbits associated with the Schroedinger equation. The resulting quantum KS invariant for a given orbit equals the mean decay rate of the probability density along the orbit, while its ensemble average measures the mean growth rate of configuration-space information for the quantum system. 相似文献
158.
159.
A simple, highly sensitive, accurate and selective method for the determination of trace amounts of Ni2+ ions in water samples is proposed. The method is based on the separation and preconcentration of Ni2+ on an octadecyl-bonded silica (ODBS) membrane disk modified by a recently synthesized Schiff’s base N,N′-bis (3-methylsalicylidene) ortho phenylene diamine (MSOPD) at pH 7. The synthesis of this extractant ligand is also described. The retained nickel on the membrane was eluted with 2×5 ml 0.5 M HNO3 and measured by flame atomic absorption spectrometry (FAAS) at 232.0 nm. The extraction efficiency and the influence of the type and least amount of eluent for the stripping of Ni2+ from the disks, pH, flow rates of sample solution and eluent, amount of MSOPD, effect of other ions, and breakthrough volume were evaluated. The maximum capacity of the membrane disks modified by 3 mg of MSOPD was found to be 146±4 μg Ni2+. The 3σ limit of detection of the method was 30 ng per 1000 ml and also an enrichment factor of 250 was obtained. The proposed method has been applied to the determination of nickel in several water samples with satisfactory results. 相似文献
160.
Our recent studies on the stem bark of Calophyllum mucigerum (Guttiferae) have yielded a new coumarin mucigerin, a prenylated xanthone cudraxanthone C and the common steroidal triterpenes friedelin and stigmasterol. Structural elucidations of these compounds were achieved using 1H NMR, 13C NMR, DEPT, COSY, HETCOR and HMBC experiments while MS gave the molecular masses. Cytotoxic assays using CEM-SS cell line (T-lymphoblastic leukemia) on the crude extracts of the stem bark indicated some activity. The crude extracts were also found to be moderately toxic against the larvae of Aedes aegypti. This article reports the isolation and identification of mucigerin as well as bioassay data. 相似文献