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排序方式: 共有233条查询结果,搜索用时 15 毫秒
71.
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73.
M. Y. A. Rahman A. A. Umar L. Roza M. M. Salleh 《Journal of Solid State Electrochemistry》2012,16(12):3947-3952
The morphology of photovoltaic material is able to influence of the performance of photoelectrochemical cell. Polyvinylpyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB), and hexamethylenetetramine (HMT) surfactant were used to modify the morphology nanostructure of TiO2 films by a simple technique, namely, liquid phase deposition during their growth process. It was found that the untreated surfactant TiO2 film produces the morphology with the mixture nanosphere and nanoflower. The film treated with PVP, CTAB, and HMT produce the nanostructure shape of nanoflower, nanowire, and nanorod, respectively. These TiO2 samples were utilized as photovoltaic materials in a photoelectrochemical cell of ITO/TiO2/electrolyte/platinum. It was found that the photovoltaic parameters such as short-circuit current density (J sc), open-circuit voltage (V oc) and fill factor are influenced by the morphology in terms of shape and particle size of the TiO2 nanostructure. The cell utilizing the TiO2 nanowire treated with PVP possesses the highest J sc and V oc of 0.100 mAcm?2 and 0.44 V. The length of the TiO2 nanowire is 6?±?2 nm, while the cell with the untreated surfactant TiO2 sample demonstrates the lowest performance. It was also found that the J sc and V oc increase with the decrease in the length of the TiO2 nanostructures. The smallest length of TiO2 possesses the best interfacial contact at TiO2/electrolyte containing iodide/triiodide redox couple. Thus, the redox reaction is optimized at this interface. 相似文献
74.
M. Umar Farooq Mubasher Jamil Muneer A. Rashid 《International Journal of Theoretical Physics》2010,49(9):2278-2287
We consider the new agegraphic dark energy model with the help of the quantum corrections to the entropy-area relation in
the setup of loop quantum gravity. Employing this new form of dark energy so called entropy-corrected new agegraphic dark
energy (ECNADE), we investigate the model of interacting dark energy and derive its equation of state (EoS). We study the
correspondence between the K-essence, tachyon and dilaton scalar fields with the interacting (ECNADE)in the non-flat FRW universe.
Moreover, we reconstruct the corresponding scalar potentials which describe the dynamics of the scalar field. 相似文献
75.
Santosh Kumari Suvarcha Chauhan Kuldeep Singh Ahmad Umar Hassan Fouad Mohammed S. Alissawi Mohammad Shaheer Akhtar 《Molecules (Basel, Switzerland)》2022,27(24)
Viscosity, speed of sound (u), and density (ρ) have been measured in aqueous glycyl glycine solution over a temperature range from 293.15 to 313.15 K with a 5 K interlude to evaluate the volumetric and compressibility properties of bio-surfactants, namely sodium cholate (NaC; 1–20 mmol∙kg−1) and sodium deoxycholate (NaDC; 1–10 mmol∙kg−1). Density and viscosity findings provide information on both solute–solute and solute–solvent types of interactions. Many other metrics, such as apparent molar adiabatic compression , isentropic compressibility , and apparent molar volume , have been calculated from speed of sound and density measurements, utilising experimental data. The results show that the zwitterionic end group in the glycyl glycine strongly interacts with NaDC and NaC, promoting its micellization. Since the addition of glycyl glycine causes the bio-surfactant molecules to lose their hydrophobic hydration, the observed concentration-dependent changes in apparent molar volume and apparent molar adiabatic compression are likely attributable to changes in water–water interactions. Viscous relaxation time () increases significantly with a rise in bio-surfactant concentration and decreases with increasing temperature, which may be because of structural relaxation processes resulting from molecular rearrangement. All of the estimated parameters have been analysed for their trends with regard to the different patterns of intermolecular interaction present in an aqueous glycyl glycine solution and bio-surfactant system. 相似文献
76.
Ahmad Umar Young Jin Choi E.-K. Suh A. Al-Hajry Yoon-Bong Hahn 《Current Applied Physics》2008,8(6):798-802
Various kind of ZnO nanostructures such as nanowires, nanonails and nanocombs were synthesized by the thermal evaporation process onto the steel alloy substrate without the use of metal catalyst or any additives. Detailed structural characterizations indicated that the grown products possess a single crystallinity with the wurtzite hexagonal crystal structure. Presence of strong optical-phonon E2 mode, in all the cases, presents the good crystallinity with the wurtzite hexagonal phase for the deposited products. Additionally, appearance of dominated, strong and sharp UV emission in the room-temperature photoluminescence spectra confirmed the good optical properties for the grown nanostructures. A vapor–solid growth mechanism has been proposed for the growth of the nanostructures. 相似文献
77.
Nisar Jan Nasir Umar Ali Ghulam Shah Afzal Farooqi Zahoor Hussain Iqbal Munawar Shah Muhammad Raza 《Cellulose (London, England)》2021,28(12):7593-7607
Cellulose - In this work we have attempted to use biomass as energy source which is abundantly available throughout the world. The work is focused on pyrolysis of sugarcane bagasse in a... 相似文献
78.
Abbasi MA Ahmad VU Zubair M Nawaz SA Lodhi MA Farooq U Choudhary MI 《Natural product research》2005,19(5):509-515
Phytochemical investigation of Symplocos racemosa resulted in the isolation of a new ethyl substituted glycoside, 1-ethyl brachiose-3'-acetate (1) along with four known compounds ketochaulmoogric acid (2), nonaeicosanol (3), triacontyl palmitate (4) and methyl triacontanoate (5). The substitution of ethyl group on 1 was natural because during the course of extraction and purification ethanol was not used. The structural elucidation of the isolated compounds was based primarily on 1D- and 2D-NMR analysis, including COSY, HMQC, and HMBC correlations. The glycoside 1 and triacontyl palmitate (4) displayed the inhibitory potential against lipoxygenase and urease enzyme, respectively. 相似文献
79.
Rana Ahmed Youness Reem Amr Assal Shahira Mohamed Ezzat Mohamed Zakaria Gad Amira Abdel Motaal 《Natural product research》2020,34(10):1475-1480
AbstractThis study focused on studying the impact of flavonoids isolated from Cleome droserifolia on HCC cell lines and to further unveil their possible impact on TP53 and its downstream tumor suppressor miRNAs. Three flavonol glycosides were isolated from C. droserifolia namely, Isorhamnetin-3-O-β-D-glucoside (1), Quercetin-3`-methoxy-3-O-(4``-acetylrhamnoside)-7-O-α-rhamnoside (2), and Kaempferol-4`-methoxy-3,7-O-dirhamnoside (3). They showed a concentration and time dependent reduction in cellular viability and anchorage-independent growth of HCC cells. Moreover, they exhibited a decrease in the migrating capacity of HepG2 cells in a pattern similar to positive control cells. (2) Showed the most potent effects in halting HCC tumorigenic activity (IC50=36?±?1.70?µM) and a repression of the cellular proliferation rate of HepG2 cells. Restoration of TP53 and its downstream tumor suppressor miRNAs; miR-15a, miR-16, miR-34a by (2) was observed. Moreover, attenuation of (2) mediated actions was shown upon using anti-miR-15a and anti-miR-16. To conclude, this study crystallizes a novel role of C. droserifolia in harnessing HCC progression in-vitro with a possible contribution of TP53/miR-15a/miR-16. 相似文献
80.
The cycloterpolymerizations of N,N-diallyl-(4-octyloxy)benzyl-, N,N-diallyl-(3,5-dioctyloxy)benzyl-, and N,N-diallyl-(3,4,5-trioctyloxy)benzyl-ammonium chloride (0-8 mol%) with hydrophilic monomer N,N-diallyl-N-carboethoxymethylammonium chloride and sulfur dioxide afforded a series of cationic polyelectrolytes (CPE). The CPEs were treated with HCl and NaOH to produce the corresponding pH-responsive cationic acid salts (CAS) and polybetaines (PB), anionic polyelectrolytes (APE) as well as polymers PB/APE containing various proportions of zwitterionic (PB) and anionic fractions (APE) in the polymer chain. Likewise, the cycloterpolymerizations of these single-, twin-, and triple-tailed hydrophobes (0-12 mol%) with hydrophilic monomer diallyldimethylammonium chloride and sulfur dioxide afforded a series of CPE in excellent yields. The polymers were characterized by different techniques including NMR and IR. The solution properties of the series of CPE were investigated by rheological techniques. The studied water soluble polymers showed different rheological behavior depending on their structure (hydrophobe type and content) as well as salinity and pH. The high shear thinning and the formation of networks at low shear would likely promote the use of such polymers in enhanced oil recovery applications. 相似文献