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Synthesis and Electrical Characterization of Lead‑Free Electronic Material: Bi(Co2/3Nb1/3)O3
S. Halder,S. Bhuyan1,R. N. P. Choudhary 한국전기전자재료학회 2019 Transactions on Electrical and Electronic Material Vol.20 No.1
A lead-free electronic compound with chemical composition Bi(Co2/3Nb1/3)O3 has been synthesized via classical solid state reaction based ceramic technology. The structure of the compound as well as the frequency and temperature field dependent resistive, conductive and dielectric properties of the specimen have been examined. The room temperature X-ray diffraction analysis exhibits the formation of the sample in orthorhombic crystal symmetry. The observed dielectric constant and tangent loss characteristics substantiate the prepared compound as a dielectric. The impedance spectra confirms the presence of negative temperature coefficient of resistance behaviour, grain and grain boundary effect in the fabricated compound. The compound modulus spectrum shows that the temperature dependent conductivity relaxation phenomenon is of nonexponential-type. The illustrated important characteristics props up the material for different device applications.
Bhuyan, Ranjan K.,Thatikonda, Santhosh K.,Dobbidi, Pamu,Renehan, J.M.,Jacob, Mohan V. Techno-Press 2014 Advances in materials research Vol.3 No.2
The microwave dielectric properties of $CeO_2$ nanoparticles (0.5, 1.0 & 1.5wt%) doped $Mg_2TiO_4$ (MTO) ceramics have been investigated at cryogenic temperatures. The XRD patterns of the samples were refined using the full proof program reveal the inverse spinel structure without any secondary phases. The addition of $CeO_2$ nanoparticles lowered the sintering temperature with enhancement in density and grain size as compared to pure MTO ceramics. This is attributed to the higher sintering velocity of the fine particles. Further, the microwave dielectric properties of the MTO ceramics were measured at cryogenic temperatures in the temperature range of 6.5-295 K. It is observed that the loss tangent ($tan{\delta}$) of all the samples increased with temperature. However, the $CeO_2$ nanoparticles doped MTO ceramics manifested lower loss tangents as compared to the pure MTO ceramics. The loss tangents of the pure and MTO ceramics doped with 1.5 wt% of $CeO_2$ nanoparticles measured at 6.5K are found to be $6.6{\times}10^{-5}$ and $5.4{\times}10^{-5}$, respectively. The addition of $CeO_2$ nanoparticles did not cause any changes on the temperature stability of the MTO ceramics at cryogenic temperatures. On the other hand, the temperature coefficient of the permittivity increased with rise in temperature and with the wt% of $CeO_2$ nanoparticles. The obtained lower loss tangent values at cryogenic temperatures can be attributed to the decrease in both intrinsic and extrinsic losses in the MTO ceramics.
Bhuyan Sudhansu Sekhar,Barik Durga Prasad,Dash Byomkesh,Rout Prachitara,Pattnaik Snigdha Samir,Verma Ramlakhan,Katara Jawahar Lal,Parameswaran C.,Devanna B. N.,Sahoo Raj Kishore,Mishra Anindita,Sabari 한국작물학회 2024 Journal of crop science and biotechnology Vol.27 No.2
Hybrid rice has a considerable yield advantage over inbred lines, but the adoption rate in India is quite slow. In a three-line hybrid rice breeding programme, the development of fertility restorer lines that have enhanced grain quality is crucial. Employment of doubled haploid (DH) technology will accelerate the development of improved R lines in a short period of time, thus hastening the pace of hybrid rice breeding. This investigation was carried out for the evaluation of genetic diversity and assessment of population differentiation in 113 DHs derived from BC1F1s of IMP. IR 42266-29-3R and Nagina 22. A total of 46 SSR (Simple Sequence Repeat) markers resulted in an average of 2.00 alleles per locus. Polymorphism information content (PIC) value ranged from 0.31 to 0.37 with an average of 0.36. RM496, RM25520, RM483 and RM553 were found to be the best markers for the identification of genetic diversity. Structure analysis classified 113 DHs into four groups, which matched the Neighbour-Joining method using UPGMA cluster analysis. The AMOVA results demonstrated substantial genetic variations within subpopulation than among sub-population. The SSR marker-based molecular fingerprinting could serve as a sound basis in the identification of genetically distant as well as in the duplicate sorting of the morphologically close population in future breeding programmes
Bhagabat Bhuyan,Suneel Kumar Srivastava,Sreeraj Puravankara,Vikas Mittal 한국고분자학회 2018 Macromolecular Research Vol.26 No.10
Successful utilization of natural anionic clays like montmorillonite and hectorite for the homogeneous dispersion of multiwalled carbon nanotubes (MWCNTs) in ethylene-co-vinyl acetate (EVA), motivated us to investigate the role of magnesium aluminium layered double hydroxide (MgAl-LDH) in a similar role. MWCNT/MgAl-LDH 3D hybrid filler (HML) was prepared from the unmodified constituents in 1:1 wt. ratio by simple dry grinding method. The dispersion of this hybrid filler with extraordinary stability was subsequently used in the preparation of EVA/HML nanocomposites by solution intercalation method. Analysis shows MWCNTs to be homogeneously dispersed in the polymer matrix in presence of LDH layers. Reinforcing efficiency of HML in EVA matrix was evaluated through detailed studies of the nanocomposites. Mechanical, thermal and dielectric properties of neat EVA are substantially improved with HML content. Maximum improvement observed in tensile strength, elongation at break and toughness are 182%, 87%, and 300% respectively at 4 wt% HML. However, best dielectric response with ~400 and ~89 times enhancement in AC conductivity and dielectric constant are observed 1 wt% HML content. Comparison of HML with previously reported MWCNT/montmorillonite (MMT) and MWCNT/hectorite 3D hybrid fillers confirms superior reinforcing efficiency of the former. Improvements in properties are attributed to homogeneous dispersion of fillers and improved polymer-filler interaction on account of synergy between MWCNTs and LDH.
Selective Sensing of Methanol by Poly(m-aminophenol)/Copper Nanocomposite
Madhusmita Bhuyan,Siddhartha Samanta,Pradip Kar 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.2
The nanocomposite film of conducting poly(m-aminophenol) with copper nanoparticles (PmAP/Cu) prepared by a singlestepprocess has been demonstrated as the sensor material for selective detection of methanol vapor. Different techniques likeFourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, X-ray diffraction spectroscopy, scanning electronmicroscopy (SEM) and transmission electron microscopy (TEM) were used to evaluate the interfacial interactions betweenPmAP and Cu nanoparticles within their conducting nanocomposites. The induced doping interaction through fluctuatingelectrostatic charge transfer between free –OH groups of the PmAP and Cu nanoparticles was confirmed from the spectralcharacterizations. About 3 wt% of Cu nanoparticles having average size of around 30–50 nm confirmed by the SEM and TEManalysis, was optimized inside the PmAP matrix in terms of better dispersion as well as achieving the highest conductivity(1.05 × 10−6 S/cm). The sensing performances, viz., % response, response time, recovery time, selectivity and reproducibilityof the nanocomposites were studied towards methanol vapor at different concentrations. The mechanism of selectivemethanol vapor sensing by PmAP/Cu nanocomposite film has been explained on the basis of selective dipole interactioncharacterized by zeta potential measurement.
Ultrastretchable Electronics Utilized by Liquid Metal and Highly Soft Elastomer
Priyanuj Bhuyan,박성준,이상민,박수진 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2
Stretchable electrical devices are compelling to be utilized for soft robotics, stretchable display and wearable electronics. A commercially available silicone (Exsil 100) that exhibits ultrastretchability (elongation at break of 5,000%), ultrasoftness (Young’s modulus of 0.02 MPa) and high tear strength (42 N/mm) is proposed as promising elastomer for fabricating soft and stretchable electronics, but the patterned structures are prone to collapse when they are released from the mold due to ultrasoftness of the materials. Herein, we developed ultrasoft and ultrastretchable electronics by non-lithographic approach with Exsil silicone and oxidized liquid metal as an elastomeric substrate and an electrode, respectively. The ultrastretchable elastomeric films patterned with highly oxidized liquid metal can find use in application of stretchable electronics such as soft robotics and pneumatics to wearable devices and sensors integrated with textiles.