排序方式: 共有144条查询结果,搜索用时 15 毫秒
101.
Tin oxide (Sn02 ) thin films are deposited by rf-magnetron sputtering and annealed at various temperatures in the range of 100-500 ℃ for 15 min. Raman spectra of the annealed films depict the formation of a small amount of SnO phase in the tetragonal Sn02 matrix, which is verified by x-ray diffraction. The average particle size is found to be about 20-30 nm, as calculated from x-ray peak broadening and SEM images. Various optical parameters such as optical band gap energy, refractive index, optical conductivity, carrier mobility, carrier concentration etc. are determined from the optical transmittance and reflectance data recorded in the wavelength range 250-2500 nm. The results are analyzed and compared with the data in the literature. 相似文献
102.
Shaheen M. A. Xiao W. Aziz M. Karim A. Saleem M. Mustaqeem M. Mehmood T. Tahir M. N. Sultan A. Simair A. Lu C. 《Russian Journal of General Chemistry》2019,89(8):1691-1695
Russian Journal of General Chemistry - The current study is devoted to the synthesis of Schiff base ligand, HL, by condensation of 5-aminosalicylic acid with o-vanillin, followed by preparing its... 相似文献
103.
Maskeen Muhammad Muddassar Zeeshan Ahmad Mehmood Obaid Ullah Hassan Mohsan 《Journal of Thermal Analysis and Calorimetry》2019,138(2):1127-1136
Journal of Thermal Analysis and Calorimetry - In the current study, heat transfer performances and flow characteristics of alumina–copper/water (Al2O3–Cu/H2O) hybrid nanofluid over a... 相似文献
104.
Shomaila Mehmood Li-Yuan Zhou Xiao-Fang Wang Xiao-Du Cheng Fan-Ju Meng Ya Wang 《Journal of carbohydrate chemistry》2019,38(3):192-211
A novel heteroglycan TLH-G was successfully isolated from Tricholoma lobayense cultivated in south China. TLH-G was composed of five monosaccharides, namely, mannose, rhamnose, glucuronic acid, glucose and galactose, and consisted of →1)-β-D-Glcp-(6→ and →1)-α-D-Galp-(3→ motifs. TLH-G had excellent scavenging activities towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals. Structure-activity relationship analysis demonstrated that glycosidic bond types, monosaccharide composition, and branching degree were more important for the antioxidant activity of polysaccharides from Tricholoma lobayense than other structural factors. All the above results showed that the growth environment played a crucial role in the structure and antioxidant activity of polysaccharides from Tricholoma lobayense. 相似文献
105.
Effect of Dielectric Constant of Solvents on the Particle Size and Bandgap of La/SnO2‐TiO2 Nanoparticles and Their Catalytic Properties
下载免费PDF全文
![点击此处可从《中国化学会会志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Muhammad Akhyar Farrukh Iqra Muneer Komal Mehmood Butt Sadaf Batool Nazia Fakhar 《中国化学会会志》2016,63(12):952-959
Lanthanum (La) supported on tin oxide‐titanium oxide (SnO2‐TiO2 ) nanoparticles were prepared by a sol–gel method followed by a hydrothermal method. Effect of different solvents (ethyl acetate, benzyl alcohol, ethylene glycol) on the particle size and catalytic activity was investigated. The nanomaterial was characterized by transmission electron microscopy, powder X‐ray diffraction, scanning electron microscopy, fourier transform infrared spectroscopy, and energy dispersive X‐ray. The catalytic and optical properties were studied using solid‐phase spectrophotometry and ultraviolet–visible spectroscopy, respectively. Gas chromatography‐mass spectrometry (GC‐MS) was used to detect the intermediates during the catalytic degradation of methylene blue. It was observed that with decrease in the dielectric constant (ε) of the solvent, the bandgap and particle size decrease and catalytic efficiency increases. Hence, the highest catalytic activity was observed with the solvent having the least dielectric constant. 相似文献
106.
In the present work, the entropy generation due to the heat transfer and fluid friction irreversibility is investigated numerically for a three-dimensional flow induced by rotating and stretching motion of a cylinder. The isothermal boundary conditions are taken into account for the heat transfer analysis. The similarity transformations are utilized to convert the governing partial differential equations to ordinary differential equations. Resulting nonlinear differential equations are solved using a numerical scheme. Expressions for the entropy generation number, the Nusselt number and the Bejan number are obtained and discussed through graphs for various physical parameters. An analysis has been made to compare the heat transfer irreversibility with fluid friction irreversibility using the expression of the Bejan number. It is found that the surface is a durable source of irreversibility and the curvature of cylinder is to enhance the fluid friction irreversibility. 相似文献
107.
E. G. Burkhard G. Mehmood L. Husain 《Journal of Radioanalytical and Nuclear Chemistry》1992,161(1):101-112
Cloud water and aerosol samples were collected at Whiteface Mountain, NY using the ASRC omnidirectional cloud water collector and high volume samples respectively. Trace element concentrations in cloud water samples were determined by neutron activation analysis and hydride generation with atomic absorption spectrometry. Agreement between the two methods for Se concentration was excellent (0.98±0.05). Aerosol samples were also analyzed for trace elements by neutron activation. Elemental analysis of cloud water and aerosols provide information useful to the study of microphysical and chemical interactions in cloud systems. 相似文献
108.
We observed a variation in the one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profile of carboxymethylated human hair proteins revealed by Coomassie staining or 14C-autoradiography in 4% of an Anglo-Celtic population in Armidale, Australia. 相似文献
109.
The objective of the study was to investigate whether the lysosomal enzyme, N-Acetyl-beta-D-glucosaminidase (NAG) activity is increased in plasma of patients with acute myocardial infarction (AMI) and to determine if there is any association between plasma levels of NAG and severity of myocardial infarction (MI). NAG activity in plasma was monitored in 69 patients with AMI and 135 normal healthy subjects using a spectrofluorimetric method. A modified Aldrich ST elevation score was used to gauge the severity of MI in terms of size of the infarct. Plasma NAG levels in AMI patients and normal healthy subjects were found to be 10.92+/-7.5 U/l and 6.8+/-2.2 U/l, respectively. These two mean value when compared by Student's t-test were significantly different P = 0.0001. No statistically significant differences in NAG activity were observed in patients in terms of gender, age, location of infarct, time from onset of chest pain to blood sampling in the hospital and size of the infarct. 相似文献
110.
Mehmood S Aziz-Ur-Rahman Ahmad Z Afza N Malik A Ahmad H Choudhary MI 《Natural product research》2008,22(13):1189-1195
Monoterpene glycosides have been isolated from the ethyl acetate soluble fraction of Indigofera hetrantha and their structures assigned to be 3,7-dimethyl-2(E),6-octadien-5-one-1-O-beta-D-6-O-acetylglucopyranoside (1) and 3,7-dimethyl-2(E), 6-octadien-5-one-1-O-[-beta-D-6'-O-acetylglucopyra-nosyl (1' --> 6')-beta-D-glucopyranoside] (2), on the basis of spectroscopic analysis including 1D and 2D NMR techniques. Compounds 1 and 2 displayed moderate inhibitory potential against the enzyme lipoxygenase. 相似文献