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Synthesis and Humidity Sensing Investigations of Nanostructured ZnSnO3

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Journal of Sensor Technology 2011年第4期1卷 116-124页

作者： Rama Singh avadhesh kumar yadav Chandkiram Gautam 不详

In this paper zinc stannate (ZnSnO3) nanoparticles was synthesized by a chemical precipitation method. The synthesized samples were characterized using X-ray powder diffraction (XRD), Differential scanning calorimetry (DSC) and UV-Visible absorption spectroscopy. Sensing material was made as pellet by hydraulic press machine under uniform pressure of 616 MPa. Then the material was annealed at 600。C. Surface morphologies of the samples were analyzed using Scanning electron microscopy (SEM) for pellet of different weight ratio annealed at 600。C. The XRD pattern indicates that ZnSnO3 has a perovskite phase with an orthorhombic structure having minimum crystallite size 4 nm. Further, humidity sensing investigations of these sensing materials were done. Our result indicate that ZnSnO3 in form of pellet annealed at 600。C for 1:4 weight ratio was most sensitive of humidity in comparison to pure SnO2 under same conditions. Maximum sensitivity of the sample was 3 GΩ/% RH which is better in comparison to pure SnO2. The results were reproducible up to ± 77% after 2 months of observations.

关键词： Zinc Stannate SEM XRD UV-Visible Absorption Spectroscopy Humidity

Crystallization Kinematics and Dielectric Behavior of (Ba,Sr)TiO3 Borosilicate Glass Ceramics

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New Journal of Glass and Ceramics 2012年第3期2卷 126-131页

作者： avadhesh kumar yadav Chandkiram Gautam Prabhakar Singh Department of Applied Physics Institute of Technology Banaras Hindu University Varanasi India Department of Physics University of Lucknow Lucknow India

Perovskite [(Ba0.6Sr0.4)TiO3]-[2SiO2-B2O3]-[K2O]-La2O3 glass was prepared by conventional melt quench method. The differential thermal analysis (DTA) was performed on glass sample in the temperature range from 100℃ to 1000℃ by different heating rate to study the crystallization kinematics. The kinetic parameters characterizing the crystallization have been determined using an Arrhenius model. Glass samples were subjected to appropriate heat treatment schedules for their suitable crystallization. X-ray diffraction analysis (XRD) of glass and glass ceramic samples were done to check the amorphous state and crystalline nature. XRD of glass ceramic sample shows the major perovskite phase of BaTiO3 (BT) along with the formation of secondary phases Ba2TiSi2O8 (BTS) and Ba2Ti2B2O9 (BTB). Scanning electron microscopy (SEM) is also studied to see the morphology of the grains of major and secondary phase formation in BST glass ceramic samples. La2O3 is played an important role to increase the nucleation of the crystallites in the glassy matrix. The addition of La22O3 results in development of well interconnected crystallites formed as major phase of BST. In this paper, we are reporting the crystallization behavior of BST borosilicate glass system and high temperature dielectric characteristics of their glass ceramics.

关键词： BST Glass Ceramics DTA Crystallization XRD SEM Dielectric Constant

Synthesis and Optical Investigations on (Ba,Sr)TiO3Borosilicate Glasses Doped with La2O3

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Optics and Photonics Journal 2013年第4期3卷 1-7页

作者： C. R. Gautam avadhesh kumar yadav Advanced Glass and Glass Ceramic Research Laboratory Department of PhysicsUniversity of Lucknow Lucknow India

In this research paper we are reporting synthesis, structural and optical investigations of barium strontium titanate borosilicate glasses with addition of La2O3. Glasses were synthesized by conventional rapid melt quench method. Infrared absorption spectra, for various (Ba,Sr)TiO3 borosilicate glass samples having glass system 64[(Ba1-xSrx)TiO3]-35[2SiO2-B2O3]-5[K2O]-1[La2O3] (x = 0.3, 0.5, 0.6, 0.8 and 1.0), were recorded over a continous spectral range from 450 - 4000 cm-1. IR spectra were analyzed to determine and differentiate the various vibrational modes in the structural changes. Raman spectroscopy of all glass samples were also carried out wavenumber range form 200 - 1500 cm-1. These two complementary spectroscopic techniques revealed that the network structure of the studied glasses is mainly based on BO3, pentaborate groups linked to BO4 tetrahedra and units placed in different structural groups, the BO3 units? are dominanting. The recorded IR and Raman spectra of different glasses are used to clarify the optical properties of the prepared glass samples correlating with their structure and compositions. UV-Vis spectroscopy was carried out in range of 200 - 800 nm. The optical band gap was found between 2.023 - 3.320 eV.

关键词： (Ba Sr)TiO3 Infrared Spectroscopy UV-Vis Spectroscopy Raman Spectroscopy

Synthesis, IR and Raman Spectroscopic Studies of (Ba,Sr)TiO3Borosilicate Glasses with Addition of La2O3

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Open Journal of Inorganic Non 2012年第4期2卷 47-54页

作者： Chandkiram Gautam avadhesh kumar yadav Vijay kumar Mishra Kunwar Vikram Department of Physics University of Lucknow Lucknow-226007 U. P. (India) Department of Physics Banaras Hindu University Varanasi-221005 U. P. (India)

A series of glasses were prepared by rapid melt quench method in the glass system (65-x)[(Ba0.6Sr0.4)TiO3]-30[2SiO2-B2O3]-5[K2O]-x[La2O3] (x = 0, 1, 2, 5 and 10). X-ray diffraction of glass samples were carried to check its amorphousity. Density of glass samples were measured using Archimedes principle. The refractive index of these glass samples lies between 2.39 to 2.80. Optical properties of these glass samples were studied using Infrared (IR) and Raman spectroscopic techniques. IR measurements were done over a continous spectral range 450 - 4000 cm-1 to study their stucture networking systematically while Raman spectra were recorded over a continous spectral range 200 - 2000 *** spectra of all glass samples showed number of absorption peaks. These absorption peaks occurs due to asymetric vibrational streching of borate by relaxation of the bond B-O of trigonal BO3. The Raman spectra of all glass samples exhibited different spectral bands and intensity of these bands changes drastically. The network structure of these glass samples is mainly based on BO3 and BO4 units placed in different structural groups.

关键词： Glasses X-Ray Diffraction Inferared Spectroscopy and Raman Spectroscopy

Experimental investigation on effective aerosol scavenging using different spray configurations with pre-injection of water mist for Fukushima Daiichi decommissioning

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Nuclear Science and Techniques 2024年第5期35卷 154-172页

作者： Rui-Cong Xu avadhesh kumar Sharma Erdal Ozdemir Shuichiro Miwa Shunichi Suzuki Department of Nuclear Engineering and Management The University of Tokyo7‑3‑1 HongoBunkyo‑KuTokyo 113‑8656Japan Nuclear Professional School The University of Tokyo2‑2

During the decommissioning of the Fukushima Daiichi nuclear power plant,it is important to consider the retrieval of resolidified debris both in air and underwater *** the subsequent retrieval of debris from the reactor building,the resolidified debris must be cut into smaller pieces using various cutting *** the cutting process,aerosol particles are expected to be generated at the submicron *** has been noted that such aerosols sizing within the Greenfield gap(0.1-1μm)are difficult to remove effectively using traditional spraying ***,to improve the aerosol removal efficiency of the spray system,a new aerosol agglomeration method was recently proposed,which involves injecting water mist to enlarge the sizes of the aerosol particles before removing them using water *** this study,a series of experiments were performed to clarify the proper spray configurations for effective aerosol scavenging and to improve the performance of the water *** experimental results showed that the spray flow rate and droplet characteristics are important factors for the aerosol-scavenging efficiency and performance of the water *** results obtained from this study will be helpful for the optimization of the spray system design for effective aerosol scavenging during the decommissioning of the Fukushima Daiichi plant.

关键词： Fukushima Daiichi decommissioning Aerosol scavenging Multiphase flow Spray system Aerosol-mist agglomeration

Existence and controllability results to second order neutral differential equation with non-instantaneous impulses

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Journal of Control and Decision 2020年第3期7卷 286-308页

作者： Muslim Malik avadhesh kumar School of Basic Sciences Indian Institute of Technology MandiMandiIndia

In this paper,existence and uniqueness of the solutions of the second order neutral differential equation with non-instantaneous impulses in a Hilbert space X are *** is followed by a brief discussion on the exact and trajectory ***,the strongly continuous cosine family of linear operators and Banach fixed point theorem are used to establish the ***,an example is given to illustrate the analytical findings.

关键词： Non-instantaneous impulsive system neutral differential equations deviated argument Banach fixed point theorem controllability