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Luminescence properties of Eu^(2+),Gd^(3+) and Pr^(3+) doped translucent Sialon phosphors

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Journal of Rare Earths 2015年第11期33卷 1142-1147页

作者： bhupendra Joshi Soo Wohn Lee Research Center for Eco Multi-Functional Nano Materials Sun Moon University

Optical properties of hot pressed Sialon ceramics doped with different rare earth oxides（REOs） i.e. Eu2O3, Gd2O3, and Pr2O3 were investigated. The α-Sialon phase was the main phase obtained after sintering as observed by X-ray diffraction（XRD）. The transparency of different samples of varying thickness measured from UV to IR region revealed that the samples were translucent in the visible region while transparent in IR region. The thin samples of 150 μm thickness had transmittance as high as 30% in the visible region. The luminescence was observed in transmittance mode to investigate the effect of sample thickness on luminescence intensity. We observed blue, yellow and red emissions in Sialon doped with Gd2O3, Eu2O3, and Pr2O3, respectively. The excitation wavelength for Gd2O3 and Pr2O3 doped samples were in UV region i.e. 280 and 270 nm, respectively, whereas, for Eu2O3 doped samples was in the blue region（460 nm）. The Eu2O3 doped Sialon having 300 μm thickness showed better white light extraction as coupled with blue LED. Moreover, the fabricated phosphor samples exhibited high hardness around 20 GPa and fracture toughness above 5 MPa·m1/2.

关键词： Sialon phosphors luminescence rare earth oxides hot pressing

An overview on metal-related catalysts: metal oxides, nanoporous metals and supported metal nanoparticles on metal organic frameworks and zeolites

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Rare Metals 2020年第7期39卷 751-766页

作者： bhupendra Kumar Singh Sunwoo Lee Kyungsu Na Department of Chemistry Chonnam National UniversityGwangju 61186Republic of Korea

Metal nanoparticles(NPs) supported on porous materials have shown great advantages in many catalytic application fields. Supported metal NPs are receiving extensive attention due to their significant contribution in a wide range of current and future applications, and this is arguably one of the fastest growing research fields. In this review, we highlight various types of metal catalysts that possess great potential in several catalytic reactions. The major focus has been on metal oxides, nanoporous metals and metal NPs supported on metal-organic frameworks(MOFs) and zeolites. Special attention has been given to the synthesis strategies and application of the NPs supported on MOFs and zeolites, which are considered highly interesting and rapidly expanding areas in heterogeneous catalysis. Finally, the prospects of these catalysts have been included in the concluding remarks.

关键词： Supported metal catalysts Porous materials Nanoporous metals Heterogeneous catalysis Zeolites Metal oxides Metal-organic frameworks

Effects of cutting types and hormonal concentration on vegetative propagation of Zanthoxylum armatum in Garhwal Himalaya,India

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Journal of Forestry Research 2017年第2期28卷 419-423页

作者： bhupendra Singh J.M.S.Rawat Department of Forestry and Natural Resources Hemvati Nandan Bahuguna Garhwal UniversityP.O.Box-59SrinagarGarhwalUttarakhand 246 174India Department of Horticulture Hemvati Nandan Bahuguna Garhwal UniversitySrinagarGarhwalUttarakhand 246 174India Department of Forestry College of Forestry and Hill AgricultureHill Campus RanichauriUttarakhand Universityof Horticulture and ForestryBharsarIndia

Experiments were carried out to define the effects of hormonal concentrations on semi-hard wood（SHW） and hard-wood（HW） branch cuttings of the ***. SHW and HW cuttings were collected in the month of March. The SHW and HW cuttings were treated with different concentration of indole-3-acetic acid and indole-3-butyric acid（IAA and IBA） and placed in vermiculite rooting medium for 90 days under 1-min misting after 10 min. Sprouting, rooting percentage, sprout number, sprout length, root number, and length were *** highest rooting and sprouting rate, 64.0 %, was obtained at the 0.3 % IBA treatment in the SHW *** sprout length and number of roots per cutting were also higher at the 0.3 % IBA treatment in the SHW cuttings. The number of shoots per cutting was higher at the 0.3 % IAA treatment in the SHW cuttings. Root length per cutting was higher in 0.4 % IBA treatment in the SHW cuttings. The results indicated that 0.3 and 0.4 % IBA treatment produce higher rooting percentages as well as the number of roots and their length in SHW cuttings. The HW cuttings produced maximum rate of 18.0 % rooting in0.5 % IBA treatment. The control set and lower concentrations of IBA and IAA completely failed to root in the mist chamber.

关键词： vegetative length Zanthoxylum roots indole cutting butyric branch shoot Root

An Additive Perks-Weibull Model with Bathtub-Shaped Hazard Rate Function

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Communications in Mathematics and Statistics 2016年第4期4卷 473-493页

作者： bhupendra Singh Department of Statistics C.C.S.UniversityMeerutIndia

In this article,an additive Perks—Weibull model capable of modeling life-time data with bathtub-shaped hazard rate function is *** model is derivedby the sum of the hazard rates of Perks and Weibull *** statisticalproperties including shapes of density and hazard rate functions,moments,and orderstatistics are *** method of maximum likelihood estimation is used for esti-mating the model *** goodness-of-fit of the model for three real datasetshaving bathtub-shaped hazard rate functions has been ***,an appli-cation for competing risk data is also given to show the flexibility of the proposedmodel.

关键词： distribution Weibull distribution Additive model Bathtub hazardrate function Maximum likelihood estimation Competing risk analysis

Utilization of inferior quality aggregates in asphalt mixes:A systematic review

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Journal of Traffic and Transportation Engineering(English Edition) 2022年第5期9卷 864-879页

作者： Surya Narayanan Sakthivel Ankit Kathuria bhupendra Singh Department of Civil Engineering Indian Institute of Technology JammuJammu 181221India Department of Civil and Infrastructure Engineering Indian Institute of Technology JodhpurKarwar 342037India

Properties of aggregates are majorly influenced by parameters of source rocks viz.,formation process,chemical composition,impurities,volume of pores,and grain *** study presents a review of aggregate treatment methods and its efficacy to enhance the quality of *** aspects of aggregate treatment methods like processing temperature,the dosage of additives,adaptability in the field is studied for three treatment methods viz.,polymer coating,cementitious coating,and chemical *** paper also presents an insight to understand the effect of different treatment methods on mix properties and performance parameters of asphalt *** review revealed that the shape properties of aggregates can be enhanced by the incorporating suitable crushing process(two-stage or three-stage).Whereas,physical and durability properties of aggregates can be improved by various treatment methods like polymer coating,Zycosoil *** was further inferred from the review that treatment methods can have moderate effects on the mechanical properties of aggregates,since,it is mostly dependent on properties of source rocks.

关键词： Mineral aggregates Inferior quality aggregates Treatment methods Asphalt mixes Mix performance

Visibility improvement and mass segmentation of mammogram images using quantile separated histogram equalisation with local contrast enhancement

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CAAI Transactions on Intelligence Technology 2019年第2期4卷 73-79页

作者： bhupendra Gupta Mayank Tiwari Subir Singh Lamba PDPM Indian Institute of Information Technology Design & Manufacturing Jabalpur MP 482005 India

In this work, the authors develop a working software-based approach named ‘linearly quantile separated histogram equalisation-grey relational analysis’ for mammogram image (MI). This approach improves overall contrast (local and global) of given MI and segments breast-region with a specific end goal to acquire better visual elucidation, examination, and grouping of mammogram masses to help radiologists in settling on more precise choices. The fundamental commitment of this work is to demonstrate that results of good quality of breast-region segmentation can be accomplished from basic breast-region segmentation if the input image has good contrast and a better interpretation of hidden details. They have evaluated the proposed strategy for MIAS-MIs. Experimental results have shown that the proposed approach works better than state-of-the-art.

关键词： develop contrast approach

Synergistic Effect of Metal Nanoparticles on the Antimicrobial Activities of Antibiotics against Biorecycling Microbes

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Journal of Materials Science & Technology 2016年第6期32卷 524-532页

作者： Chandni Khurana Purnima Sharma O.E Pandey bhupendra Chudasama Laboratory of Nanomedicine School of Physics and Materials ScienceThapar UniversityPatiala 147004India Department of Applied Sciences Chandigarh UniversityMohali 160055India Department ofBiotechnology Thapar UniversityPatiala 147004India

Biorecycling microbes, which have critical functionalities in natural cycles, are essential to sustain eco-system of the earth. Any alterations in these cycles caused by the mutations of microbes could be a potential threat to life on earth. Antibiotics leached from pharmaceutical waste, animal food and agribusiness prod- ucts are accumulating in the environment. Metal nanoparticles are also accumulating in environment because of their extensive use as biocidal agent in domestic products. Interaction of antibiotics and metal nanoparticles with eco-ffiendly microorganisms has a potential to alter the ecosystem of the earth. In this article, we have studied the antibacterial activities of silver and copper nanoparticles and their for- mulations with antibiotics, tetracycline, and kanamycin against biorecycling microbes, Bacillus subtilis and Pseudomonas fluorescens. Strong synergistic effect of metal nanoparticles on the antimicrobial ac- tivities of commercial antibiotics has been observed. Antimicrobial activity of tetracycline improves by 286%-346% and 0%-28% when being tested in the presence of 250 ppm of silver and copper nanoparticles, respectively. For kanamycin, the improvement is 154%-289% for silver and 3%-20% for copper nanoparticles. Irrespective of the antibiotics and tested organisms, synergy is more prominent for silver nanoparticles even at their minimum active concentration （100 ppm）. This study demonstrates that the combination of metal nanoparticles with antibiotics could be more fatal to ecosystem than either the metal nanoparticles or the antibiotics alone.

关键词： Synergy Nanoparticles Antibiotics Biorecycling microbes Antibacterial activities

Radiation effect on temperature distribution in three-dimensional Couette flow with suction or injection

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Applied Mathematics and Mechanics(English Edition) 2007年第3期28卷 309-316页

作者： bhupendra Kumar Sharma Mamta Agarwal R.C.Chaudhary Department of Mathematics University of RajasthanJaipur-302004India

A theoretical analysis of three-dimensional Couette flow with radiation effect on temperature distribution has been analysed, when the injection of the fluid at the lower stationary plate is a transverse sinusoidat one and its corresponding removal by constant suction through the upper porous plate is in uniform motion. Due to this type of injection velocity, the flow becomes three-dimensional. The effect of Prandtl number, radiation parameter and injection parameter on rate of heat transfer has been examined by the help of graphs. The Prandtl number has a much greater effect on *** distribution than the injection or radiation parameter.

关键词： Couette flow three-dimensional heat transfer radiation incompressible

The effect of laser surface texturing on the tribological performance of different Sialon ceramic phases

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Progress in Natural Science:Materials International 2016年第4期26卷 415-421页

作者： bhupendra Joshi Khagendra Tripathi Gobinda Gyawali Soo Wohn Lee Research Center for Eco Multifunctional Nano Materials Sun Moon University

A tribological performance was carried out on different types of hot press Sialon ceramics regarding the phases, i.e., the α-Sialon phase, the β-Sialon phase, and the α/β-Sialon composite phase. The different phases of Sialon ceramics were analyzed by XRD patterns. For the tribological performance, the Sialon ceramics were laser textured and the starved lubrication method was applied with different dimple pitches under a load of 10 N at room temperature. The material having a dimple pitch of 200 mm shows the lowest coefficient of friction. The α/β-Sialon composite phase shows the least coefficient of friction i.e. 0.04 and 0.1 for the textured and polished(without being textured) samples, respectively. The Sialon ceramics show mild wear and therefore, the wear rate of the steel ball(mating partner) was taken into account for the wear analysis. The α-Sialon phase having a higher hardness shows the least wear in comparison to the α/β-Sialon composite phase and the β-Sialon phase.

关键词： Sialon Hot press Laser surface texturing Coefficient of friction Wear