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Journal of Materials Science & Technology 2011年第11期27卷 967-972页

作者： Lakhwant Singh vibha Chopra Department of Physics Guru Nanak Dev University

The carbon based boron oxynitride （BCNO） phosphor was synthesized by solid state reaction between boric acid （H3BO3） and melamine （C3H6N6） in the molar ratios of 1：1 and 2：1 respectively at different temperatures up to 1400℃. The composition with molar ratios 1：1 of starting materials is found to be highly crystalline with an average particle size of 38 nm and the lattice constants a=b=0.251 nm and c=0.666 nm. The solid state reaction of boric acid and melamine in the composition 2：1 leads to the formation of compound in the semi-crystalline state under the same conditions of preparation, but its phase cannot be recognised. The X-ray diffraction （XRD） spectra, transmission electron microscopy （TEM） and scanning electron microscopy （SEM） images of BCNO compound confirm the phase, nanometre size and shape respectively of synthesized material. The photoluminescence （PL） spectra of the synthesized BCNO products reveals that the electronic structure of BCNO compound can be controlled by changing the molar ratios of starting materials and heating temperatures. These synthesized compounds are very interesting and important candidate materials for light emitter.

关键词： BCNO Chemical synthesis Nitrides Photoluminescence spectroscopy

Experimental Evaluation of Certain Pursuit and Evasion Schemes for Wheeled Mobile Robots

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International Journal of Automation and computing 2019年第4期16卷 491-510页

作者： Amit Kumar Aparajita ojha Computer Science and Engineering Indian Institute of Information Technology Kota Jaipur 302017 India Computer Science and Engineering Indian Institute of Information Technology Design and Manufacturing Jabalpur 482005 India

Pursuit-evasion games involving mobile robots provide an excellent platform to analyze the performance of pursuit and evasion strategies. Pursuit-evasion has received considerable attention from researchers in the past few decades due to its application to a broad spectrum of problems that arise in various domains such as defense research, robotics, computer games, drug delivery, cell biology, etc. Several methods have been introduced in the literature to compute the winning chances of a single pursuer or single evader in a two-player game. Over the past few decades, proportional navigation guidance (PNG) based methods have proved to be quite effective for the purpose of pursuit especially for missile navigation and target tracking. However, a performance comparison of these pursuer-centric strategies against recent evader-centric schemes has not been found in the literature, for wheeled mobile robot applications. With a view to understanding the performance of each of the evasion strategies against various pursuit strategies and vice versa, four different proportional navigation-based pursuit schemes have been evaluated against five evader-centric schemes and vice-versa for non-holonomic wheeled mobile robots. The pursuer′s strategies include three well-known schemes namely, augmented ideal proportional navigation guidance (AIPNG), modified AIPNG, angular acceleration guidance (AAG), and a recently introduced pursuer-centric scheme called anticipated trajectory-based proportional navigation guidance (ATPNG). Evader-centric schemes are classic evasion, random motion, optical-flow based evasion, Apollonius circle based evasion and another recently introduced evasion strategy called anticipated velocity based evasion. The performance of each of the pursuit methods was evaluated against five different evasion methods through hardware implementation. The performance was analyzed in terms of time of interception and the distance traveled by players. The working environme

关键词： Pursuit-evasion wheeled mobile robot proportional navigation trajectory planning target interception

Role of cerium as a promoter and process optimization studies for dehydration of glycerol to acetol over copper chromite catalyst

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Journal of Rare Earths 2022年第1期40卷 63-72页

作者： S.Basu vibha Shree A.K.Sen Depanment of Chemical Engineering Birla Institute of TechnologyMesraRanchiJharkhandIndia

Cerium-promoted silica supported copper chromite catalyst was synthesized from acid hydrolysis of sodium silicate by sol-gel *** catalyst was characterized by Brunauer-Emmett-Teller(BET)method,field-emission scanning electron microscopy(FESEM),X-ray diffraction(XRD),H_(2)-temperature programmed reduction(H_(2)-TPR),NH3-temperature programmed desorption(NH3-TPD)and pyridine adsorbed Fourier transform infrared spectroscopy(Py-FTIR).Among cerium doped catalysts,5 wt%of Ce promoted copper chromite supported by 40 wt%of silica(SiCuCr40-Ce5)shows the largest BET surface *** analysis of the reduced form of the catalyst shows both CeO_(2)/Ce_(2)O_(3) redox system and CuO/Cu_(2)O/Cu redox ***-FTIR shows the maximum number of Lewis acid sites for SiCuCr40-Ce5 than *** highest acetol selectivity with analytical reagent(AR)grade glycerol conversion is observed for SiCuCr40-Ce5 at 200℃for 3 h in a batch reactor at atmospheric *** promotion lowers the reaction te mperature with enhanced glycerol conve rsion and increased acetol *** the above catalyst shows higher conversion for laboratory reagent(LR)grade glycerol but it reduces acetol *** addition of glucose into the LR grade glycerol further reduces glycerol conversion and decreases the acetol selectivity to *** may be due to the presence of iron as impurity in LR grade *** analysis of spent catalyst shows the absence of redox catalytic system and the pore volume reduces identified by BET *** analysis of the spent catalyst shows graphite-like carbon deposition in the spent catalvst.

关键词： Glycerol dehydration Cerium-promoted copper chromite Acetol XRD Raman Rare earths

Standardization of harvesting age of bamboo shoots with respect to nutritional and anti-nutritional components

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Journal of Forestry Research 2013年第1期24卷 83-90页

作者： Ashok K. Pandey Vijayalakshmi ojha Tropical Forest Research Institute Indian Council of Forestry Research and EducationP.O. RFRCMandla RoadJabalpur- 482 021India.

Bamboo shoots can be harvested at different ages but the data on the changes in nutritional composition with age are scanty. We standardized harvesting age of bamboo shoots in central India to obtain best quality produce with respect to nutritional composition. The shoots harvested on different days （2–20 days after emergence from ground） were analyzed for their nutritional （dietary fibres, carbohydrates, proteins, total phenols, ascorbic acid, sodium, potassium, phosphorus, calcium, magnesium and phenolic acids） and anti nutritional （cyanogen） constituents. A significant variation （at p ≤ 0.5） was observed in the nutritional composition of shoots of Dendrocalamus asper, D. strictus and Bambusa tulda harvested at different days. An overall decrease was observed in proteins and total phenols while dietary fibres and carbohydrates increased with ages. Significant variation （at p ≤ 0.5） was also observed in phenolic acids while minerals did not vary significantly. Results revealed that the optimum harvesting age for D. asper, D. strictus and B. tulda was on 10–14 days, 6–10 days and 10–16 days （after emergence from the ground） respectively. These results can be used to obtain quality bamboo shoots.

关键词： Bamboo shoots harvesting nutritional status central India phenolic acids anti-nutrient

Study of Electronic Density of States: Zintl Alloys

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Communications in Theoretical Physics 2011年第2期55卷 362-364页

作者： Ashwani Kumar Durga Prasad ojha Post Graduate Department of Physics Andhra Loyola College

In the present work the electronic density of states of liquid,viz.,Zintli alloys,have been studied only at the composition of their maximum resistivity to have an elementary idea about the behaviors of the alloys with respect to nearly free electron *** study reveals that the anomalous electronic behavior of liquid Li-Pb,Na-Pb,Li-Sn,and Na-Sn can be attributed to the preferential ordering of unlike atoms.

关键词： alloys thermodynamics of solutions density of states phase diagram

Geochemical signatures of potassium metasomatism in anthracite from the Himalayan fold‑thrust belts of Sikkim,India

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International Journal of Coal Science & Technology 2022年第2期9卷 48-69页

作者： Santanu Ghosh Anwita ojha Atul Kumar Varma Coal Geology and Organic Petrology Laboratory Department of Applied GeologyIndian Institute of Technology(Indian School of Mines)DhanbadJharkhand 826004India Department of Earth Sciences Indian Institute of Technology BombayPowaiMumbaiMaharashtra 400076India

The present study focuses on the inorganic geochemical features of the bituminous coal samples from the Raniganj and the Jharia Basins,as well as the anthracite samples from the Himalayan fold-thrust belts of Sikkim,*** SiO_(2)content(48.05 wt%to 65.09 wt%and 35.92 wt%to 50.11 wt%in the bituminous and anthracite samples,respectively)and the ratio of Al_(2)O_(3)/TiO_(2)(6.97 to 17.03 in the bituminous coal samples and 10.34 to 20.07 in the anthracite samples)reveal the intermediate igneous source rock composition of the *** ratio of the K_(2)O/Al_(2)O_(3)in the ash yield of the bituminous coal samples(0.03 to 0.09)may suggest the presence of kaolinite mixed with montmorillonite,while its range in the ash yield of the anthracite samples(0.16 to 0.27)may imply the presence of illite mixed with *** chemical index of alteration values may suggest the moderate to strong chemical weathering of the source rock under sub-humid to humid climatic *** plot of the bituminous coal samples in the A–CN–K diagram depicts the traditional weathering trend of parent rocks,but the anthracite samples plot near the illite feld and are a bit ofset from the weathering *** may imply the plausible infuences of the potassium-metasomatism at post coalifcation stages,which is further supported by high K_(2)O/Na_(2)O ratio(29.88–80.13).The Fourier transform infrared spectra further reveal the hydroxyl stretching intensity of illite in the anthracite samples substantiating the efect of the epigenetic *** decrease in total kaolinite intensity/compound intensity of quartz and feldspar may provide additional evidence towards this epigenetic event.

关键词： Himalayan fold-thrust belts Anthracite Potassium metasomatism Kaolinite to quartz-feldspar intensity ratio Montmorillonite stretching and bending intensities Illite-stretching frequency

An experimental study on optimizing parameters for sand consolidation with organic-inorganic silicate solutions

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Petroleum 2024年第3期10卷 483-493页

作者： Saurabh Mishra Geetanjali Chauhan Keka ojha Department of Energy Science and Technology Centre for Advanced StudiesLucknowIndia Department of Petroleum Engineering and Earth Sciences Indian Institute of Petroleum and EnergyVisakhapatnamIndia Department of Petroleum Engineering Indian Institute of Technology(ISM)DhanbadIndia

Sand production along with the oil/gas detrimentally affects the oil production rate,downhole&subsurface *** equipment and various chemicals like epoxy resin,furan resin,phenolic resin,*** used in the industry to reduce or eliminate this *** the present study,a blend of organic and inorganic silicates are used to consolidate loose sand in the presence and absence of crude oil using a core flooding *** effects of chemical concentration,pH,curing temperature and time,and the presence of residual oil on the consolidation treatment results such as compressive strength and permeability retention,were investigated and ***-IR and FE-SEM characterization techniques were employed to investigate the interaction between the chemical molecules and the sand *** current binding agent exhibited a viscosity of less than 6 cP at room temperature,which facilitates efficient pumping of binding agent into the desired formation through the well *** developed mixture demonstrated consolidation properties across all pH ***,during the experimental investigation,the curing time and temperature was carefully optimized at 12 h and 423.15K,respectively to achieve the highest compressive strength of 2021 psi while achieving the permeability retention of 64%.The current chemical system exhibited improved consolidation capacity and can be effectively utilized for sand consolidation treatment in high-temperature formations.

关键词： Chemical sand consolidation Rheology Compressive strength Permeability retention Silicate system Curing

Interacting tachyonic scalar field

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Communications in Theoretical Physics 2021年第2期73卷 102-107页

作者： A Kundu S D Pathak V K ojha Department of Physies Lovely Professional UniversityPhagwaraPunjab144411India School of Sciences SAGE University BhopalMadhya Pradesh462022India

We discuss the coupling between dark energy and matter by considering a homogeneous tachyonic scalar field as a candidate for dark *** obtained the functional form of scale factor by assuming that the coupling strength depends linearly on the Hubble parameter and energy *** also estimated the cosmic age of the Universe for different values of coupling constant.

关键词： dark energy dark matter scalar field achyonic scalar field

Facile synthesis of graphitic carbon-nitride supported antimony-doped tin oxide nanocomposite and its application for the adsorption of volatile organic compounds

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Journal of Environmental Sciences 2019年第5期31卷 35-42页

作者： Devi Prashad ojha Jun Hee Song Han Joo Kim Department of Convergence Technology Engineering Chonbuk National University Eco-friendly Machine Parts Design Center Chonbuk National University

Antimony-doped tin oxide(ATO) nanoparticles with an average size of ～ 6 nm were prepared by co-precipitation and subsequent heat treatment. Graphitic carbon nitride(g-CN)/ATO hybrid nanocomposite was designed by the combination of thermally synthesized g-CN and ATO nanoparticles by ultrasonication. The materials were characterized using N2 adsorption/desorption(BET), X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), transmission electron microscopy(TEM) and Fourier transform infrared spectroscopy(FTIR). A mixture of five volatile organic compounds(VOCs, chloroform, benzene, toluene, xylene and styrene) was used to compare the adsorption capacity of the samples. The adsorption capacity of ATO nanoparticles was improved by the addition of g-CN. Experimental data showed that, among the five VOCs,chloroform was the least adsorbed, regardless of the samples. The g-CN/ATO showed nearly three times greater adsorption capacity for the VOC mixture than pure ATO. The unchanged efficiency of VOC adsorption during cyclic use demonstrated the completely reversible adsorption and desorption behavior of the nanocomposite at room conditions. This economically and environmentally friendly material can be a practical solution for outdoor and indoor VOC removal.

关键词： Antimony-doped tin oxide(ATO) Graphitic carbon nitride(g-CN) Volatile organic compounds(VOC) Adsorption