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排序方式: 共有283条查询结果,搜索用时 31 毫秒
31.
Hamid Latif M. Shahid Rafique R.S. Rawat Shahzad Naseem 《Applied Surface Science》2008,254(22):7505-7511
In the paper an attempt has been made to use the laser-induced plasma as an X-ray source for the growth of nanostructures on the surface of gold. For this purpose, an Nd:YAG laser operated at second harmonics (λ = 532 nm, E = 400 mJ) is used to produce plasma from analytical grade 5N pure Al, Cu and W targets. An analytical grade (5N pure) gold substrate was irradiated by X-rays generated from Al, Cu and W plasma under the vacuum ∼10−4 Torr. The surface was analyzed by two techniques, XRD and AFM. The aberrations in the XRD peaks show that there are significant structural changes in the exposed gold, in terms of decreased reflection intensities, increased dislocation line density, changes in the d-spacing and disturbance in the periodicity of the planes. AFM used to explore the topography of the irradiated gold reveals that regardless of the source, nm sized hillocks have been produced on the gold surface. The roughness of the surface has increased due to the growth of these hillocks. 相似文献
32.
Faizan Ur Rahman Maryam Bibi Ezzat Khan Abdul Bari Shah Mian Muhammad Muhammad Nawaz Tahir Adnan Shahzad Farhat Ullah Muhammad Zahoor Salman Alamery Gaber El-Saber Batiha 《Molecules (Basel, Switzerland)》2021,26(15)
In this study six unsymmetrical thiourea derivatives, 1-isobutyl-3-cyclohexylthiourea (1), 1-tert-butyl-3-cyclohexylthiourea (2), 1-(3-chlorophenyl)-3-cyclohexylthiourea (3), 1-(1,1-dibutyl)-3-phenylthiourea (4), 1-(2-chlorophenyl)-3-phenylthiourea (5) and 1-(4-chlorophenyl)-3-phenylthiourea (6) were obtained in the laboratory under aerobic conditions. Compounds 3 and 4 are crystalline and their structure was determined for their single crystal. Compounds 3 is monoclinic system with space group P21/n while compound 4 is trigonal, space group R3:H. Compounds (1–6) were tested for their anti-cholinesterase activity against acetylcholinesterase and butyrylcholinesterase (hereafter abbreviated as, AChE and BChE, respectively). Potentials (all compounds) as sensing probes for determination of deadly toxic metal (mercury) using spectrofluorimetric technique were also investigated. Compound 3 exhibited better enzyme inhibition IC50 values of 50, and 60 µg/mL against AChE and BChE with docking score of −10.01, and −8.04 kJ/mol, respectively. The compound also showed moderate sensitivity during fluorescence studies. 相似文献
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35.
Nazir Muhammad Shahzad Ghasemi Ali Dezfulizadeh Amin Abdalla Ahmad N. 《Journal of Thermal Analysis and Calorimetry》2021,144(6):2653-2664
Journal of Thermal Analysis and Calorimetry - The aim of this work is the energy analysis of a novel semicircle-shaped parabolic trough solar collector filled with the water–boehmite alumina... 相似文献
36.
Ayub Khurram Shahzad Zaman Waqas Qamar Miran Waheed Ali Meesam Abbas Zain Mushtaq Umair Shahzad Asif Yang Ji 《Research on Chemical Intermediates》2022,48(10):4227-4248
Research on Chemical Intermediates - Volatile organic compounds (VOCs) represent a very important class of pollutants that causes serious health effects. There is an urgent requirement to establish... 相似文献
37.
Afif Ahmed Radenahmad Nikdalila Rahman Seikh Mohammad Habibur Torino Nico Saqib Muhammad Hossain Shahzad Park Jun-Young Azad Abul Kalam 《Journal of Solid State Electrochemistry》2022,26(1):111-120
Journal of Solid State Electrochemistry - Protonic ceramic fuel cells have become extremely interesting due to their high power output at the intermediate temperature range... 相似文献
38.
Yaser Acikbas Rifat Capan Funda Yukruk Matem Erdogan 《Journal of inclusion phenomena and macrocyclic chemistry》2018,92(1-2):137-146
The optical characterization and chemical vapor sensing properties of 1,7-dibromo-N,N′-(bicyclohexyl)-3,4:9,10-perylene diimide thin film against to organic vapors were discussed in this study by using spin coating, UV–Vis spectroscopy, atomic force microscopy, surface plasmon resonance (SPR) and Quartz Crystal Microbalance (QCM) techniques. The perylene diimide thin films were fabricated with a refractive index values from 1.55 to 1.60 and thicknesses in the range between 15.80 and 26.32 nm using different spin speeds from 1000 to 5000 rpm. In this study, perylene diimide thin film sensor was exposed to dichloromethane, chloroform, carbon tetrachloride, tetrahydrofuran and ethyl acetate vapors by using both SPR and QCM techniques. Also, the swelling behaviors of the perylene diimide thin films prepared at different spin speeds were investigated with respect to dichloromethane vapor at the room temperature by using SPR data. Diffusion coefficients were found to be 11.34?×?10?17 (1000 rpm), 2.56?×?10?17 (3000 rpm) and 0.38?×?10?17 cm2 s?1 (5000 rpm) for dichloromethane vapor by using the Fick’s law of diffusion. It might be proposed that perylene diimide thin film optical chemical sensor element has a good sensitivity and selectivity for the dichloromethane vapor at room temperature. 相似文献
39.
Bushra S Bukhari M Imran Mahwish Bashir Saira Riaz Shahzad Naseem 《Journal of Sol-Gel Science and Technology》2018,87(3):554-567
Aim of the present work is to prepare zirconia nanofibers using microwave assisted sol–gel method. Both honey and microwave powers are employed as structure directing agents to improve the stability and reduce the crystallite size. Honey, acting as capping agent, prevents the particles from hard agglomeration. Soft agglomeration or less agglomeration results in smaller crystallite size that prevents the transformation of tetragonal to monoclinic phase resulting in stabilized tetragonal zirconia (t-ZrO2). Zirconium oxychloride is used as precursor of zirconium and deionized water as solvent. Effect of microwave powers, in the range of 100–900?W with interval of 200?W, on zirconia stabilization is observed. X-ray diffraction analysis shows the presence of phase pure t-ZrO2 at low microwave power ~?100?W with crystallite size ~?26?nm. Formation of phase pure t-ZrO2 at low microwave power is due to the presence of sufficient amount of honey to coat the zirconia crystals. Relatively higher x-ray density has been observed in case of phase pure t-ZrO2 at 100?W of microwave power. This high density and phase purity reveals the high value of hardness (~?1503?HV). Scanning electron microscopy analysis reveals the formation of well-separated nanofibers without agglomeration at 100?W. These nanofibers are purposed for bone implants and bone grafting. Structural transformation along with hard agglomeration is observed with increase in microwave powers from 500?W to 900?W. FTIR and Raman fundamental tetragonal bands, appearing at 490?cm?1 and 148?cm?1, respectively, confirm the formation of t-ZrO2 at low microwave power. Sample with phase purity exhibits high grain boundary resistance (1.95?MΩ) along with high dielectric constant (~?74) and low tangent loss (at log f?=?4.0). It is worth mentioning here that phase pure t-ZrO2 at very low microwave power (~100?W) with high density and well-separated nanofibers has been obtained without any post heat treatment. 相似文献
40.
Shahzad Iqbal Shanshan Yu Feng Zhao Yachen Wang Jun Tian Le Jiang Yi Du Xiaoqi Yu Lin Pu 《Tetrahedron letters》2018,59(37):3397-3400
A 1,1′-bi-2-naphthol (BINOL) based dialdehyde (R)-1 is found to exhibit selective fluorescent response towards cellular thiols, l-Cys, l-Hcy, and GSH. (R)-1 reacts with l-Trp to form a Schiff base 2 which quenches the emission of l-Trp at λ?=?340. Coordination of 2 with Zn(ll) leads to greatly enhanced emission at λ?=?530?nm. When the in situ generated 2 from the combination of the solution of (R)-1 (1.0?×?10?5?M)?+?Trp (2?equiv) +Zn(OAc)2 (2 equiv) is treated with l-Cys, l-Hcy, and GSH, different fluorescent responses at three emission wavelengths, including 340, 421 and 530?nm, are observed. This allows the in situ generated 2 to be used as a ratiometric fluorescent probe to discriminate these three biothiols. NMR study of (R)-1 with D- or l-Cys in the presence of Zn(II) shows that the unique reactivity of Cys provides basis for the selective ratiometric fluorescent response. (R)-1?+?Zn(II) also exhibits enantioselective fluorescent response toward D- and l-Cys. 相似文献