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排序方式: 共有329条查询结果,搜索用时 15 毫秒
21.
Dadan Hermawan Izdiani Mohd Yatim Khaulah Ab Rahim Mohd Marsin Sanagi Wan Aini Wan Ibrahim Hassan Y. Aboul-Enein 《Chromatographia》2013,76(21-22):1527-1536
A simple solid phase extraction (SPE) method coupled with high performance liquid chromatography (HPLC) using UV detector and microemulsion electrokinetic chromatography (MEEKC) has been developed and compared for the quantitative determination of miconazole nitrate in pharmaceutical formulation. For HPLC method, two parameters were optimized, namely, the wavelength and the mobile phases. The optimized condition was at the 225 nm wavelength and the mobile phase of ACN:MeOH (90:10 v/v). There are seven MEEKC parameters that were optimized, in this research, which were applied to voltage, temperature, wavelength, sodium dodecyl sulfate (SDS) concentration, buffer pH, buffer concentration and butan-1-ol concentration. The optimum MEEKC condition was obtained using 86.35 % (w/w) 2.5 mM borate buffer pH 9, 0.25 % (w/w) SDS, 0.8 % (w/w) ethyl acetate, 6.6 % w/w butan-1-ol and 6.0 % (w/w) acetonitrile. The combination of SPE using a diol column with HPLC–UV and the MEEKC methods were successfully applied for the determination of miconazole nitrate in a pharmaceutical formulation with the recovery percentage of 98.35 and 92.50 %, respectively. 相似文献
22.
An extremely efficient heterogeneous protocol is reported for the one-pot, three-component synthesis of a series of dihydropyrimidinones (DHPMs) in the presence of ZnO nanoparticles in water as a green solvent. The ZnO nanoparticles exhibited excellent catalytic activity and the proposed methodology is capable of providing the desired products in good yields (65–94%) within short reaction times. After the reaction course, ZnO nanoparticles can be recycled and reused without any apparent loss of activity, which makes this ecofriendly process cost-effective. 相似文献
23.
24.
This study reports the results of a numerical investigation of three-dimensional turbulent buoyant recirculating flow within
rooms with heated obstruction. The study involves the solution of partial differential equations for the conservation of mass,
momentum, energy, concentration, turbulent energy and its dissipation rate. These equations were solved together with algebraic
expressions for the turbulent viscosity and heat diffusivity using k-ε turbulence model by performing simulations on FLUENT
6.3. The CFD method was validated via comparing with the available experimental data. A comparison with experimental results
shows good agreement. This means that the present computer code has a good capability to simulate 3D airflow and effect of
obstruction within room. The present study demonstrates the flow behavior, thermal distribution and CO2 concentration inside the room in the presence of heat flux obstruction. Two different configurations of ventilation system
have been studied. Mixing and Displacement ventilation system have been used in two geometries depending on location of opening
inlet. The ventilation effectiveness for heat removal (ET) is used to evaluate the indoor climate and average temperature is an important parameter in designs the ventilation systems.
Two notable points are presented; first, mixing ventilation is depending on throw of jet. CO2 concentration and temperature distribution have been effected in upper zone more than occupied zone with presence the obstruction.
Second notable points are presented; in displacement ventilation buoyancy effect is considerable. Vertical temperature gradient
above the obstruction implies that both fresh air and CO2 concentration. 相似文献
25.
Rahim Hosseinzadeh‐Khanmiri Yaser Kamel Zahra Keshvari Ahmad Mobaraki Gholam Hossein Shahverdizadeh Esmail Vessally Mirzaagha Babazadeh 《应用有机金属化学》2018,32(9)
In this research, preparation of the magnetic nanoparticle, coating by a silica shell using (3‐aminopropyl) triethoxysilane and synthesis of a novel sulfonic acid‐substituted imidazolium‐based ionic liquid onto the surface of these particles via a multi‐component reaction, is described. The functionalized nanoparticles was loaded by Ni nanoparticles and characterized by means of techniques such as XRD, FTIR, SEM, EDX, TEM, TGA and ICP‐OES. The nanostructures have spherical shapes that ranged in size from 80 to 100 nm. The catalytic activity of these nanoparticles was tested in aerobic oxidation of primary alcohols that showed good performance in the wide range of primary alcohols in water at mild reaction conditions. As a second step of this work, the tandem oxidative synthesis of alkylacrylonitriles and bisindolylmethanes were investigated using primary alcohols under oxidation conditions. This catalyst system can be recovered using external magnet and reused for five consecutive cycles without significantly less of its activity. 相似文献
26.
Zarei-Jelyani Mohammad Babaiee Mohsen Baktashian Shaghayegh Eqra Rahim 《Journal of Solid State Electrochemistry》2019,23(10):2771-2783
Journal of Solid State Electrochemistry - Binders play a significant role in the electrochemical performance of anodes in lithium–ion batteries. In this study, mesocarbon microbead (MCMB)... 相似文献
27.
Saeed Bahadorikhalili Samira Ansari Haleh Hamedifar Leila Ma'mani Mohsen Babaei Rahim Eqra Mohammad Mahdavi 《应用有机金属化学》2019,33(4)
In this paper, a novel catalyst is introduced based on the immobilization of palladium on modified magnetic graphene oxide nanoparticles. The catalyst is characterized by several methods, including transmission electron microscopy, scanning electron microscopy, X‐ray fluorescence, vibrating‐sample magnetometer, Fourier transform‐infrared and dynamic light scattering (DLS) analysis. The activity of the catalyst was investigated in the synthesis of 4(3H)‐quinazolinones via Pd‐catalyzed carbonylation‐cyclization of N‐(2‐bromoaryl) benzimidamides by Mo (CO)6. The Mo (CO)6 is used as a carbon monoxide source for performing the reaction under mild conditions. The catalyst showed good reusability, and no change in activity was observed after 10 cycles of recovery. 相似文献
28.
This paper proves that a difference field (E, ) admits quantifierelimination if and only if E is an algebraically closed field,and is an integer power of the Frobenius automorphism. 1991Mathematics Subject Classification 03C60, 12H10. 相似文献
29.
Majid M. Heravi Samaheh Sadjadi Sodeh Sadjadi Hossein A. Oskooie Rahim Hekmat Shoar Fatemeh F. Bamoharram 《中国化学会会志》2009,56(2):246-250
Silica‐supported Preyssler nanoparticles (H14[NaP5W30O110])/SiO2 are used as a new and recyclable catalyst for the preparation of 1,3‐diaryl‐5‐spirohexahydropyrimidines via a one‐pot condensation of anilines, formaldehyde, and cyclohexanone. 相似文献
30.
This paper describes a new structure of left-handed metamaterial (LHM) based on parametric studies using Computer Simulation
Technology (CST) software. The LHM structure is a combination of the modified square rectangular split ring (MSRR) and the
capacitance loaded strip (CLS). In this paper, the parametric studies are used to see the effect of frequency and the negative
value range of permeability (μ
r
) and permittivity (ε
r
) toward changes of LHM parameters. The changes in the dimension of MSSR and CLS affect the S
11 and S
21 of the LHM structure which will affect the values of permeability and permittivity. The values of permeability and permittivity
were extracted from the reflection and transmission coefficient data. The studies proved that the LHM structure can be designed
within the frequency range of interest. 相似文献