排序方式: 共有184条查询结果,搜索用时 15 毫秒
61.
62.
Ahmad Reza Massah Beheshteh Asadi Azadeh Molseghi Hamid Javaherian Naghash 《Tetrahedron》2009,65(36):7696-7705
Some metal hydrogen sulfates were used as acid catalysts in the N-acylation of different sulfonamides using carboxylic acid chlorides and anhydrides as acylating agents under both heterogeneous and solvent-free conditions. Al(HSO4)3 and Zr(HSO4)4 were found to have the highest activity and catalyze the reactions efficiently to furnish the primary N-acyl sulfonamides (RCONHSO2R′), secondary N-acylsulfonamides (RCONR″SO2R′) and bis-N-acylsulfonamnides [RCO(SO2R′)N-R″-N(SO2R′)COR] in good to high yield. The mild reaction conditions, inexpensive and low toxicity of catalysts and easy work-up procedure make this method attractive. 相似文献
63.
Sayyed Mohammad Ali Ne’mati Majid Ghassemi Azadeh Shahidian 《Transport in Porous Media》2017,119(2):461-480
Chemotherapy as one of the most utilized cancerous tumor treatment methods introduces undesired side effects due to penetrating toxic drugs into the healthy organs. Delivery of anticancer therapeutic agents to solid tumors is also problematic. The purpose of current study is to investigate the penetration of magnetic drug carriers (MDCs) within the cancerous solid tumor tissue under the influence of external magnet. Capillary wall and tumor tissue is modeled as a saturated porous media. In order to solve the coupled governing equations, mass, momentum and concentration, an in-house finite volume-based code is developed and utilized. Results show the penetration of MDCs into the tumor in the absence of magnetic field is minimal and is limited to the surface of the tumor. On the other hand, under the influence of external magnet the penetration of MDCs within the tumor increases exponentially. They also penetrate deep into the tumor and cover the entire tumor which increase the effectivity and decrease the side effect of the treatment. 相似文献
64.
Ze Xu Yi-Xuan Liu Maryam Azadeh Hao-Cheng Thong Yuqi Jiang Fang-Zhou Yao Zhen-Xing Yue Zhong-Tai Zhang Zi-Long Tang Jing-Feng Li Heng Wang Till Frömling Ke Wang 《Angewandte Chemie (International ed. in English)》2023,62(9):e202216776
Recent advances in perovskite ferroelectrics have fostered a host of exciting sensors and actuators. Defect engineering provides critical control of the performance of ferroelectric materials, especially lead-free ones. However, it remains a challenge to quantitatively study the concentration of defects due to the complexity of measurement techniques. Here, a feasible approach to analyzing the A-site defect and electron in alkali metal niobate is demonstrated. The theoretical relationships among defect concentration, conductivity, and oxygen partial pressure can be established based on the defect chemistry equilibria. The type and concentration of defects are reflected through the conductivity variation with oxygen partial pressure. As a result, the variation of defect concentration gives rise to defect-driven interfacial polarization, which further leads to distinct properties of the ceramics. e.g., abnormal dielectric behavior. Furthermore, this study also suggests a strategy to manipulate defects and charges in perovskite oxides for performance optimization. 相似文献
65.
66.
Synthesis and Characterization of Tricarbastannatranes and Their Reactivity in B(C6F5)3‐Promoted Conjugate Additions 下载免费PDF全文
Azadeh Kavoosi Prof. Eric Fillion 《Angewandte Chemie (International ed. in English)》2015,54(18):5488-5492
The synthesis and characterization of a series of tricarbastannatranes, in the solid state and in solution, are described. The structures of the complexes [N(CH2CH2CH2)3Sn](BF4), [N(CH2CH2CH2)3Sn](SbF6), [N(CH2CH2CH2)3Sn]4[(SbF6)3Cl], and [(N(CH2CH2CH2)3Sn)2OH][MeB(C6F5)3] were determined by X‐ray crystallography. Furthermore, the B(C6F5)3‐promoted conjugate addition of alkyl‐tricarbastannatranes to benzylidene derivatives of Meldrum’s acid was investigated, and detailed mechanistic studies are presented. 相似文献
67.
This critical review focuses on the origins and preparation of bio-based surfactants, defined here as non-soap, amphiphilic molecules in which the carbon atoms are derived from annually renewable feedstocks. Environmental concerns and market pressures have led to greater relevance of these chemicals in commercial applications in recent years and extensive research has gone into exploring new classes of surfactants. Highlighted here are examples of bio-based surfactants that are produced on an industrial scale and/or are based on abundant starting materials. The trend of increasing use of renewable resources as starting materials for surfactants is introduced, followed by extensive discussion of the major classes of bio-derived hydrophobes and hydrophiles. Also discussed is the status of research and development with regard to biosynthetically produced surfactants. Finally, concluding remarks address the potential for new surfactant molecular structures as a result of ongoing development in the chemistry of biorefineries, i.e., that the transformation of lignocellulose into fuels is likely to support the manufacturing of new bio-based coproducts (238 references). 相似文献
68.
MohammadReza Elahifard Elham Fazeli Azadeh Joshani MohammadReza Gholami 《Surface and interface analysis : SIA》2013,45(7):1081-1087
Direct CO dissociation is seen the main path of the first step in the Fischer–Tropsch Synthesis (FTS) on the reactive iron surfaces. Cu/Fe alloy film is addressed with various applications over face‐centered‐cubic (fcc)‐Cu and body‐centered‐cubic (bcc)‐Fe in the FTS, i.e. preventing iron carbide formation (through direct CO dissociation) by moderating the surface reactivity and facilitating the reduction of iron surfaces, respectively. In this study by density functional theory, the stable configurations of CO molecule on various Cu/Fe alloys over fcc‐Cu(100) and bcc‐Fe(100) surfaces with different CO coverage (25% and 50%) have been evaluated. Our results showed that the ensemble effect plays a fundamental role to CO adsorption energy on the surface alloys over bcc‐Fe(100); on the other hand, the ligand effect determines the CO stability on the fcc‐Cu(100) surface alloys. CO dissociation barrier was also calculated on the surface alloys that showed although the CO dissociation process is thermodynamically possible on the more reactive surface alloys, but according to their high barrier, CO dissociation does not occur directly on these surfaces. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
69.
Abdolali Alizadeh Tahereh Firuzyar Azadeh Mikaeili 《Journal of heterocyclic chemistry》2013,50(3):676-679
An efficient, one‐pot synthetic protocol for polyfunctionalized 1,4‐dihydropyridine‐fused‐1,3‐diazaheterocycles, a class of biologically active compounds, starting from 1,1‐bis(methylthio)‐2‐nitroethylene, 1,n‐diamine, arylaldehyde, and malononitrile is described. The reactions are completed within 12–15 h under refluxing conditions and in the presence of 10 mol % of piperidine as a basic catalyst to produce the title compounds in 60–75% yields. 相似文献
70.
The present research employs density functional theory(DFT) computations to analyze the structure and energy of complexes formed by psoralen drug with alkali(Li+, Na+, K+) and alkaline earth(Be2+, Mg2+, Ca2+) metal cations. The computations are conducted on M06-2X/aug-cc-pVTZ level of theory in the gas phase and solution. The Atoms in Molecules(AIM) and natural bond orbital(NBO) analyses are applied to evaluating the characterization of bonds and the atomic charge distribution, respectively. The results show that the absolute values of binding energies decrease with going from the gas phase to the solution. Furthermore, the considered complexes in the water(as a polar solvent) are more stable than the CCl4(as a non-polar solvent). The DFT based chemical reactivity indices, such as molecular orbital energies, chemical potential, hardness and softness are also investigated. The outcomes show that the considered complexes have high chemical stability and low reactivity from the gas phase to the solution. Finally, charge density distributions and chemical reactive sites of a typical complex explored in this study are obtained by molecular electrostatic potential surface. 相似文献