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21.
Vishnu Awasthi Sushil K. Pandey Saurabh K. Pandey Shruti Verma Mukul Gupta Shaibal Mukherjee 《Journal of Materials Science: Materials in Electronics》2014,25(7):3069-3076
The growth of CIGS thin films on soda-lime glass substrates at different substrate temperatures by dual ion beam sputtering system in a single-step route from a single quaternary sputtering target with the composition of Cu (In0.70 Ga0.30) Se2 was reported. The effects of the substrate temperature on structural, optical, morphological and electrical properties of CIGS films were investigated. Stoichiometry of one such film was investigated by X-ray photoelectron spectroscopy. All CIGS films had demonstrated a strong (112) orientation located at 2θ ~26.70o, which indicated the chalcopyrite structure of films. The value of full-width at half-maximum of (112) peak was reduced from 0.58° to 0.19° and crystallite size was enlarged from 14.98 to 43.05 nm as growth temperature was increased from 100 to 400 °C. However, atomic force microscope results showed a smooth and uniform surface at lower growth temperature and the surface roughness was observed to increase with increasing growth temperature. Hall measurements exhibited the minimum film resistivity of 0.09 Ω cm with a hole concentration of 2.42 × 1018 cm?3 and mobility of 28.60 cm2 V?1 s?1 for CIGS film grown at 100 °C. Film absorption coefficient was found to enhance nominally from 1 × 105 to 2.3 × 105 cm?1 with increasing growth temperature from 100 to 400 °C. 相似文献
22.
J. N. Srivastava K. K. Awasthi C. D. Dwivedi Hansraj G. N. Mathur 《Fullerenes, Nanotubes and Carbon Nanostructures》2002,10(2):107-116
Fullerene production by arc-discharge method using graphite electrodes has been studied with respect to influence of different design and operational parameters on fullerene yield in a constant arc fullerene reactor. The design parameters like reactor length, diameter, heat transfer area and operational parameters like voltage, current, pressure, coolant flow rate, graphite evaporation rate and electrode diameter etc. have been experimentally studied in detail to establish a relationship between these parameters and fullerene yield. All the parameters affecting the yield have been correlated by dimensional analysis and an equation to calculate the fullerene yield is derived. It was observed experimentally as well as by dimensional analysis that many favorable parameters for getting good yield are linked with other parameters which also get changed if the favorable parameters are changed and thus it is difficult to make a substantial change in the yield of fullerenes. The relationship established between the yield and parameters is however useful in optimising fullerene yield in a reactor and also helpful in designing a futuristic fullerene reactor of improved yield and productivity. The fullerene yield from different designs of reactors is obtained in the range of 4% to 20%. 相似文献
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S Awasthi SS Singhal SK Srivastava RT Torman P Zimniak J Bandorowicz-Pikula SV Singh JT Piper YC Awasthi S Pikula 《Canadian Metallurgical Quarterly》1998,37(15):5231-5238
Dinitrophenyl S-glutathione (DNP-SG) ATPase is a 38 kDa membrane protein expressed in erythrocytes and other tissues. Although stimulation of ATP hydrolysis catalyzed by DNP-SG ATPase has been demonstrated in the presence of several structurally unrelated amphiphilic ions, structural and functional properties of this protein have not been well-defined. In the present study, we have developed an improved protocol for the purification of DNP-SG ATPase and investigated its kinetic and substrate-binding properties. The purification procedure was based on highly specific elution of the 38 kDa protein from DNP-SG affinity resin in the presence of ATP. The protein could not be eluted using either ADP or adenosine-5'-[beta,gamma-methylene]triphosphate (methylene-ATP), a nonhydrolyzable analogue of ATP. Doxorubicin (DOX), a weakly basic anthracycline chemotherapy agent, was found to be the preferred activator for stimulation of ATP hydrolysis by the enzyme. ATP binding to the enzyme was demonstrated using 8-azido-ATP photoaffinity labeling and binding of trinitrophenyl (TNP)-ATP, a fluorescent analogue of ATP. The photoaffinity labeling of DNP-SG ATPase (38 kDa) was saturable with respect to 8-azido ATP (Kd = 2 microM), indicating that the enzyme was capable of specific and saturable binding to ATP. DNP-SG binding was evident from the purification procedure itself and was also demonstrable by quenching of tryptophan fluorescence. Results of quenching of tryptophan fluorescence as well as radioactive isotope-binding studies indicated that DOX was bound to the purified protein as well. 相似文献
26.
In this article, a small‐printed Bluetooth/LTE/UWB/X‐band/Ku‐band monopole antenna with high rejection triple band‐notch is presented. Notched bands include WiMAX (IEEE802.16 3.30‐3.80 GHz), WLAN IEEE802.11a/h/j/n (5.15‐5.35 GHz, 5.25‐5.35 GHz, 5.47‐5.725 GHz, and 5.725‐5.825 GHz), and downlink satellite system (7.1‐7.9 GHz). By including inverted T‐shaped stub and etching two C‐shaped slots on the radiating patch, triple band‐notch function is obtained with measured high band rejection (VSWR = 14.59 at 3.69 GHz, VSWR = 39.40 at 5.42 GHz, and VSWR = 6.43 at 7.57 GHz) and covers a UWB useable fractional bandwidth of 157.75% (2.285‐19.35 GHz = 17.065 GHz). Reconfigurable characteristics are obtained using PIN diodes, which control the individual notched bands. Proposed antenna is printed on Rogers RT/duroid5880 substrate with compact dimensions of 20 × 22 mm2. Proposed antenna finds its applications for Bluetooth, LTE, UWB, other multiple wireless applications for close range radar (8‐12 GHz) in X‐band, and satellite communication in Ku‐Band with omnidirectional pattern in H‐plane. 相似文献
27.
Saxena Gaurav Jain Priyanka Awasthi Yogendra Kumar 《Wireless Personal Communications》2020,112(1):105-121
Wireless Personal Communications - In this paper, a UWB–MIMO antenna with the WLAN band-notch (5.1–5.85 GHz) characteristic is offered. This antenna consists of two radiated... 相似文献
28.
Kalpana Awasthi T. P. Yadav P. R. Mishra S. Awasthi O. N. Srivastava 《Bulletin of Materials Science》2008,31(3):313-318
The macroscopic coaxial carbon cylinders (dia. ∼0.5 cm with varying lengths, ∼ 7–10 cm) consisting of aligned carbon nanotube
(CNT) stacks have been prepared by controlled spray pyrolysis method. The coaxial carbon cylinders of CNT stacks have been
formed directly inside the quartz tube. Another study is done on multi-walled CNTs (MWNTs)-polymer (e.g. polyethylene oxide
(PEO), polyacrylamide (PAM)) composite films. We have investigated the structural, electrical and mechanical properties of
MWNTs-PEO composites. Composites with different wt% (between 0 and 50 wt% of MWNTs) have been prepared and characterized by
the scanning electron microscopic technique. Enhanced electrical conductivity and mechanical strength were observed for the
MWNTs-PEO composites. We have also studied the electrical property of MWNTs-PAM composite films. 相似文献
29.
Ammonolysis of fatty acids to the corresponding fatty acid amides is efficiently catalysed by Candida antartica lipase (Novozym 435). In the present paper lipase-catalysed synthesis of erucamide by ammonolysis of erucic acid and urea in organic solvent medium was studied and optimal conditions for fatty amides synthesis were established. In this process erucic acid gave 88.74 % pure erucamide after 48 hour and 250 rpm at 60 degrees C with 1:4 molar ratio of erucic acid and urea, the organic solvent media is 50 ml tert-butyl alcohol (2-methyl-2-propanol). This process for synthesis is economical as we used urea in place of ammonia or other amidation reactant at atmospheric pressure. The amount of catalyst used is 3 %. 相似文献
30.
Nitesh Dutt Ankush Hedau Ashwani Kumar Mukesh Kumar Awasthi Sachin Hedau Chandan Swaroop Meena 《亚洲传热研究》2024,53(3):1501-1531
The thermohydraulic performance (THP) of a solar air heater (SAH) duct with staggered D-shaped ribs as roughness geometry is examined in this work using three-dimensional numerical investigation. The investigation is carried out at roughness parameters of radius of rib to transverse pitch (r/Ptv) ratios of 0.1–0.35 and longitudinal pitch to radius of rib (Plg/r) ratios of 4–10 under varied operating circumstances of Reynolds number (Re) from 10,200 to 20,200. The maximum Nusselt number (Nu) is obtained to be 81.3 at Re of 20,200, r/Ptv as 0.1, and Plg/r as 4. In contrast, the maximum friction factor (f) is obtained to be 0.0169 at Re of 10,200, r/Ptv as 0.35, and Plg/r as 4. In the range of parameters examined, the maximum enhancement in Nusselt number (Nu/Nus) is observed to be 1.35 at an optimal parameter of r/Ptv as 0.1, Plg/r as 4, and Re as 10,200. Correspondingly, the enhancement in the friction factor (f/fs) at this optimum parameter is 1.87. The maximum value of the THP parameter is found to be 1.1 at the same optimum range of parameters. In further analysis, correlations were developed for Nusselt number (Nu) and friction factor (f) in terms of r/Ptv, Plg/r, and Re with a deviation of ±2% and ±1.5%, respectively. 相似文献