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71.
Kurmi Yashwant Saxena Prankur Kirar Bhupendra Singh Gangwar Suchi Chaurasia Vijayshri Goel Aditya 《Multidimensional Systems and Signal Processing》2022,33(3):981-1000
Multidimensional Systems and Signal Processing - The agricultural yield of any country provides the base for the development of that nation. Sustainable growth needs to maintain crop production up... 相似文献
72.
Bhupendra C. Trivedi Dace Grote Thomas O. Mason 《Journal of the American Oil Chemists' Society》1981,58(1):17-20
Rhenium heptoxide, a known catalyst for hydrogenation of car-boxylic acids to alcohols, forms synergistic combinations with
palladium, platinum, rhodium and ruthenium catalysts. This effect is also seen at lower presures (500 psi). Synergism is also
mainfest when rhenium and palladium (or rhodium) are used as supported catalysts on silica and used in a flow mode. An interaction
of un-known nature between the metals suggests itself. The process is not very efficient at lower pressures giving lower conversion
in the flow mode. At higher temperatures needed for higher rates, significant participation of side reactions such as decarboxylation
of the acid and hydrogenolysis of the alcohol occurs yielding hydrocarbons. 相似文献
73.
Release of metallic nanoparticles in soil poses a serious threat to the ecosystem as they can affect the soil properties and impose toxicity on soil microbes that are involved in the biogeochemical cycling. In this work, in vitro ecotoxicity of as‐synthesised copper nanoparticles (CuNPs) on Bacillus subtilis (MTCC No. 441) and Pseudomonas fluorescens (MTCC No. 1749), which are commonly present in soil was investigated. Three sets of colloidal CuNPs with identical physical properties were synthesised by chemical reduction method with per batch yield of 0.2, 0.3 and 0.4 gm. Toxicity of CuNPs against these soil bacteria was investigated by MIC (minimum inhibitory concentration), MBC (minimum bactericidal concentration), cytoplasmic leakage and ROS (reactive oxygen species) assay. MIC of CuNPs were in the range of 35–60 µg/ml and 35–55 µg/ml for B. subtilis and P. fluorescens respectively, while their MBC ranged from 40–70 µg/ml and 40–60 µg/ml respectively. MIC and MBC tests reveal that Gram‐negative P. fluorescens was more sensitive to CuNPs as compared to Gram positive B. subtilis mainly due to the differences in their cell wall structure and composition. CuNPs with smaller hydrodynamic size (11.34 nm) were highly toxic as revealed by MIC, MBC tests, cytoplasmic leakage and ROS assays, which may be due to the higher active surface area of CuNPs and greater membrane penetration. Leakage of cytoplasmic components and generation of extra‐cellular oxidative stress by reactive oxygen species (ROS) causes cell death. The present study realizes in gauging the negative impact of inadvertent release of nanoparticles in the environment, however, in situ experiments to know its overall impact on soil health and soil microflora can help in finding solution to combat ecotoxicity of nanoparticles. 相似文献
74.
Jin Hyuk Choi Gobinda Gyawali Dhani Ram Dhakal Bhupendra Joshi Soo Wohn Lee 《金属学报(英文版)》2020,33(4):573-582
Ni-W-TiC composite coatings were prepared via electrodeposition technique by dispersing the different amount of TiC particles into the plating bath.The Ni-W and Ni-W-TiC composite coatings containing different concentrations of TiC particles were characterized by using the scanning electron microscope,X-ray diffraction technique,Vickers microhardness test,surface roughness test,and tribology test.The results show that the Ni-W coatings containing reinforced TiC particles have shown a typical FCC Ni-W crystal structure with significantly higher Vickers microhardness.The amount of dispersed TiC particles into the plating bath considerably affected codeposition weight percent of TiC into the Ni-W matrix,as revealed by the EDS analysis.Ni-W-TiC samples demonstrated the decreased abrasive wear as compared to Ni-W coating and no characteristic features observed for the adhesive wear.Similarly,an improvement in coefficient of friction was observed in Ni-W-TiC composite coating as compared to Ni-W coating. 相似文献
75.
76.
Manisha Dhiman Bhupendra Chudasama Vinod Kumar K.B. Tikoo Sonal Singhal 《Ceramics International》2019,45(3):3698-3709
In the present study, synthesis of different rare earth (RE) doped cobalt ferrite nanoparticles was done via facile sol-gel auto-combustion method using four different RE metal ions: Eu, Gd, Dy and Nd. The RE substituted cobalt ferrite nanoparticles were then characterized using FT-IR, powder XRD, HR-TEM, SAED, EDX, VSM and DRS techniques. From the characterization results, a significant variation in the structural, magnetic and optical properties of pure cobalt ferrite was observed with the introduction of different RE metal ions. This change in the properties was emerged due to the distortion of the ferrite crystal lattice due to replacement of smaller ionic radii Fe3+ ions with the comparatively larger ionic radii RE3+ metal ions. The catalytic activity of the fabricated RE doped cobalt ferrite nanoparticles was studied for the photo-Fenton degradation of cationic and anionic dyes. Under visible light irradiation, the as prepared RE doped nanoparticles exhibited great enhancement in the photo-Fenton degradation of dye molecules as compared to pure cobalt ferrite nanoparticles. The enhancement in the degradation rate was ascribed to the generation of defects in the crystal lattice, lower crystallite size and reduced band gap energy values which facilitated the facile transfer of photo-generated holes and electrons. Best catalytic results were obtained for CoNd0.08Fe1.92O4 for SO dye (k?=?2.23?×?10?1 min?1) which were found to be around 9 times higher than the pure cobalt ferrite nanoparticles (k?=?0.23?×?10?1 min?1). 相似文献
77.
78.
79.
Efficient Near Infrared to Visible and Near‐Infrared Upconversion Emissions in Transparent (Tm3+, Er3+)‐α‐Sialon Ceramics
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Yuwaraj K. Kshetri Bhupendra Joshi Luis Armando Diaz‐Torres Soo Wohn Lee 《Journal of the American Ceramic Society》2017,100(1):224-234
Intense visible and near‐infrared frequency upconversion and a frequency downconversion photoluminescence have been reported for the first time in Tm3+ and Er3+ co‐doped transparent α‐Sialon ceramics under 980 nm excitation. The α‐Sialon ceramics were prepared by hot‐press sintering technique. Intense upconversion bands at 554, 678, 803 nm, and a downconversion band at 1530 nm were observed as a result of the efficient energy transfer between Er3+ and Tm3+ ions. The quadratic dependence of upconversion intensities on the excitation power indicates that the upconversion process is governed by two‐photon absorption process. The sintered samples of thickness 0.20 mm have transparency above 80% in the range of 2000 to 4200 nm and it reaches as high as 82% at 3350 nm. Moderately low phonon energy was found with the highest frequency band at 828 cm?1. These novel properties manifest the potential applications of transparent α‐Sialon ceramics as a multifunctional material. 相似文献
80.
S. S. Nikam M. P. Suryawanshi M. A. Gaikwad J. H. Kim A. V. Moholkar 《Journal of Materials Science: Materials in Electronics》2017,28(7):5165-5173
Polyvinyl alcohol is used as a surfactant in the chemical bath deposition of PbS thin films, which causes compact, pinhole free and uniform PbS thin films. Influence of deposition time on the structural, optical, morphological, compositional, electro-chemical and photo-electrochemical (PEC) properties of the PbS thin films are studied. The charge transfer resistance is analysed using electrochemical impedance spectroscopy. The best PEC device fabricated using optimized deposition time (3 h) showed short circuit current density (Jsc) of 1.68 mA. After annealing the optimised P63 sample at 75?°C for 1.5 h the composition changed from Pb rich to near stoichiometric. For typical PA sample Jsc improves to 2.13 mA and photo conversion efficiency advances from 0.045 to 0.072%. 相似文献