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排序方式: 共有462条查询结果,搜索用时 281 毫秒
91.
Babita Kumari Shailja Sharma Nirupama Singh Anuradha Verma Vibha R. Satsangi Sahab Dass Rohit Shrivastav 《International Journal of Hydrogen Energy》2014
ZnO thin films, showing nano-ridges at the surface and the top layer embedded with metal (Ag/Au) nanoparticles (MNP), were obtained by sol-gel synthesis, using zinc acetate dihydrate [(CH3.COO)2Zn.2H2O] as precursor. The method involved prior synthesis of Ag and Au nanoparticles via biological reduction of AgNO3 and HAuCl4, respectively, using algae Spirulina platensis. The XRD analysis indicated dominant evolution of wurtzite ZnO phase. Low-angle shift in peaks, seen with nanoparticles embedded films, indicated partial diffusion of metals into ZnO lattice. Band gap energy was least affected and lied in the expected range. AFM and SEM analysis revealed the surface topography and morphology, while EDX analysis confirmed the elemental stoichiometry and existence of Ag/Au nanoparticles in samples. Significant gain in photoelectrochemical current using MNP embedded films is largely accountable to the improvement in electrical conductance and the role played by metal nanoparticles in charge-carrier separation, collection and transport. 相似文献
92.
Aadesh P. Singh Saroj Kumari Rohit Shrivastav Sahab Dass Vibha R. Satsangi 《International Journal of Hydrogen Energy》2008
This paper describes the photoelectrochemical studies on nanostructured iron doped titanium dioxide (TiO2) thin films prepared by sol-gel spin coating method. Thin films were characterized by X-ray diffraction, Raman spectroscopy, spectral absorbance, atomic force microscopy and photoelectrochemical (PEC) measurements. XRD study shows that the films were polycrystalline with the photoactive anatase phase of TiO2. Doping of Fe in TiO2 resulted in a shift of absorption edge towards the visible region of solar spectrum. The observed bandgap energy decreased from 3.3 to 2.89 eV on increasing the doping concentration upto 0.2 at.% Fe. 0.2 at.% Fe doped TiO2 exhibited the highest photocurrent density, ∼0.92 mA/cm2 at zero external bias. Flatband potential and donor density determined from the Mott–Schottky plots were found to vary with doping concentration from −0.54 to −0.92 V/SCE and 1.7 × 1019 to 4.3 × 1019 cm−3, respectively. 相似文献
93.
M. Sterlin Leo Hudson P.K. Dubey D. Pukazhselvan Sunil Kumar Pandey Rajesh Kumar Singh Himanshu Raghubanshi Rohit. R. Shahi O.N. Srivastava 《International Journal of Hydrogen Energy》2009,34(17):7358
This paper deals with how the Hydrogen Energy may play a crucial role in taking care of the environmental scenario/climate change. The R&D efforts, at the Hydrogen Energy Center, Banaras Hindu University have been described and discussed to elucidate that hydrogen is the best option for taking care of the environmental/climate changes. All three important ingredients for hydrogen economy, i.e., production, storage and application of hydrogen have been dealt with. As regards hydrogen production, solar routes consisting of photoelectrochemical electrolysis of water have been described and discussed. Nanostructured TiO2 films used as photoanodes have been synthesized through hydrolysis of Ti[OCH(CH3)2]4. Modular designs of TiO2 photoelectrode-based PEC cells have been fabricated to get high hydrogen production rate (10.35 lh−1 m−2). However, hydrogen storage is a key issue in the success and realization of hydrogen technology and economy. Metal hydrides are the promising candidates due to their safety advantage with high volume efficient storage capacity for on-board applications. As regards storage, we have discussed the storage of hydrogen in intermetallics as well as lightweight complex hydride systems. For intermetallic systems, we have dealt with material tailoring of LaNi5 through Fe substitution. The La(Nil − xFex)5 (x = 0.16) has been found to yield a high storage capacity of 2.40 wt%. We have also discussed how CNT admixing helps to improve the hydrogen desorption rate of NaAlH4. CNT (8 mol%) admixed NaAlH4 is found to be optimum for faster desorption (3.3 wt% H2 within 2 h). From an applications point of view, we have focused on the use of hydrogen (stored in intermetallic La–Ni–Fe system) as fuel for Internal Combustion (IC) engine-based vehicular transport, particularly two and three-wheelers. It is shown that hydrogen used as a fuel is the most effective alternative fuel for circumventing climate change. 相似文献
94.
D. Kalpana S.H. Cho S.B. Lee Y.S. Lee Rohit Misra N.G. Renganathan 《Journal of power sources》2009,190(2):587-591
For the first time, a new carbon–carbon composite electrode material for supercapacitors is prepared by simple KOH activation of waste newspaper. The amorphous nature and surface morphology of the carbon composite are investigated by X-ray diffraction (XRD), N2 adsorption/desorption and scanning electron microscopy. The surface area and pore diameter are 416 m2 g−1 and 5.9 nm, respectively. Electrochemical characteristics are evaluated by cyclic voltammetry (CV) and charge–discharge tests in 6.0 M KOH at a 1 mA cm−2 current density. The CV results reveal a maximum specific capacitance of 180 F g−1 at a 2 mV s−1 scan rate and the data explore a development of new use for waste paper into a valuable energy storage material. 相似文献
95.
Simultaneous influence of market power structure, advertising and quality efforts on the optimal pricing decisions and performance of a multi-echelon supply chain under uncertainty have received scant attention in the literature. We focus on this gap by examining a serial decentralised three-echelon supply chain consisting of a supplier, a manufacturer and a retailer. The uncertainty associated with customer demand, marginal production costs and effort costs is expressed as linguistic or fuzzy variables. We analyse centralised supply chain to obtain all benchmark parameters. We investigate four decentralised supply chain cases through fuzzy game theoretic approach. We compare among three Stackelberg games with various supply chain leaderships and a vertical Nash. Our key findings are as follows. First, the manufacturer puts least quality effort while retailer puts least advertising effort when they act as Stackelberg leader in a three-echelon supply chain. Second, supplier's per unit price is governed by the channel leadership in three-echelon supply chain while retail prices are less affected by the leadership. We investigate the impact of fuzzy degree of quality and advertising sensitivity on optimal profit distribution among agents. We present numerical analysis to illustrate the importance of the derived theoretical results and discuss additional managerial insights. 相似文献
96.
Machine Learning - The goal in extreme multi-label classification (XMC) is to learn a classifier which can assign a small subset of relevant labels to an instance from an extremely large set of... 相似文献
97.
Multimedia Tools and Applications - Visualizations help decipher latent patterns in music and garner a deep understanding of a song’s characteristics. This paper offers a critical analysis of... 相似文献
98.
Nadavala Siva Kumar Abhishek Dhar Ahmed A. Ibrahim Rohit L. Vekariya Poonam Bhadja 《International Journal of Hydrogen Energy》2018,43(36):17057-17063
In the present work, we have designed and synthesized two carbazole and phenothiazine donor moieties based metal-free organic sensitizers and their codes are WCBZ2 and WPTZ2 respectively. These sensitizers have been used for photocatalytic hydrogen (H2) evaluation application. The sensitizers exhibit good light absorption capability and electrochemical properties as well. For increasing water splitting capacity, incorporate platinum salt on TiO2 semiconductor photoanode was performed and compared hydrogen evolution with pure TiO2 photoanode. We have also studied the influence of the sensitizer's concentration and the effect of pH of the medium was explored. Using a theoretical measurement optimized both the synthesized dimer dyes structure geometry and the calculated their HOMO-LUMO energy level. Here also reported optimized pH and concentration of sensitizers in the reaction medium and found that the high hydrogen generation efficiency from water splitting is 138.3 μmol (348 TONs) by the WPTZ2 dye. 相似文献
99.
Valada Abhinav Mohan Rohit Burgard Wolfram 《International Journal of Computer Vision》2020,128(5):1239-1285
International Journal of Computer Vision - Learning to reliably perceive and understand the scene is an integral enabler for robots to operate in the real-world. This problem is inherently... 相似文献
100.
A novel SiC-20 vol% TiC composite prepared via a two-step sintering technique using 6.5 vol% Y2O3-Sc2O3-MgO exhibited high deformation (60 %) on hot forging attributed to the high-temperature plasticity of TiC (ductile to brittle transition temperature ~800 °C) and fine-grained microstructure (~276 nm). The newly developed SiC-TiC composite exhibited a ~2-fold increase in nominal strain as compared to that of monolithic SiC. The plastic deformation caused by grain-boundary sliding in monolithic SiC was supplemented by the plastic deformation of TiC in the SiC-TiC composite. The hot-forged composite exhibited anisotropy in its microstructure and mechanical and thermal properties due to the preferred alignment of α-SiC platelets formed in situ. The relative density, flexural strength, fracture toughness, and thermal conductivity of the composite increased from 98.4 %, 608 MPa, 5.1 MPa?m1/2, and 34.6 Wm?1 K?1 in the as-sintered specimen to 99.9 %, 718–777 MPa, 6.9–7.8 MPa?m1/2, and 54.8–74.7 Wm?1 K?1, respectively, on hot forging. 相似文献