• Journal of Industrial and Engineering Chemistry
• /
• v.67
• /
• pp.12-27
• /
• 2018

Supercapacitors (SCs) has gained an impressive concentration by the researchers due to its advantages such as high energy and power densities, long cyclic life, rapid charge-discharge rates, low maintenance and desirable safety. Hence it has been widely utilized in energy storage and conversion devices. Among the different components of SC, electrodes play a vital role in the performances of SCs. In this review, we present the recent advances in 2-D nanostructured metal nitrides, carbides, and phosphides based materials for SC electrodes. Finally, the electrochemical stability and designing approach for the future advancement of the electrode materials are also highlighted.

• Journal of Electrochemical Science and Technology
• /
• v.13 no.4
• /
• pp.472-478
• /
• 2022

Solar energy harvesting is practiced by various nations for the purpose of energy security and environment preservation in order to reduce overdependence on oil. Converting solar energy into electrical energy through Photovoltaic (PV) module can take place either in on-grid or off-grid applications. In recent time Lithium battery is exhibiting its presence in on-grid applications but its role in off-grid application is rarely discussed in the literature. The preliminary capacity and Peukert's study indicated that the battery quality is good and can be subjected for life cycle test. The capacity of the battery was 10.82 Ah at 1 A discharge current and the slope of 1.0117 in the Peukert's study indicated the reaction is very fast and independent on rate of discharge. In this study Lithium Iron Phosphate battery (LFP) after initial characterization was subjected to life cycle test which is specific to solar off-grid application as defined in IEC standard. The battery has delivered just 6 endurance units at room temperature before its capacity reached 75% of rated value. The low life of LFP battery in off-grid application is discussed based on State of Charge (SOC) operating window. The battery was operated both in high and low SOC's in off-grid application and both are detrimental to life of lithium battery. High SOC operation resulted in cell-to-cell variation and low SOC operation resulted in lithium plating on negative electrode. It is suggested that to make it more suitable for off-grid applications the battery by default has to be overdesigned by nearly 40% of its rated capacity.

• Journal of Electrochemical Science and Technology
• /
• v.13 no.1
• /
• pp.128-137
• /
• 2022

For this study, the sol gel method was used to synthesize the spinel LiNi_0.5Mn_1.5O₄ (LNMO) electrode material. Structural, morphological, electrochemical, and kinetic aspects of the LNMO have been characterized. The synthesized LNMO was indexed with the Fd3m cubic space group. The excellent capacity retention indicates that the spinel framework of LNMO has the ability to withstand high rate charge-discharge throughout long cycle tests. The Li diffusion coefficient (D_Li) changes non-monotonically across three orders of magnitude, from 10^-9 to 10^-12 cm² s^-1 determined from GITT method. The variation of D_Li seemed to be related to three oxidation reactions that happened throughout the charging process. A small dip in D_Li at the beginning stage of Li deintercalation is correlated with the oxidation of Mn³⁺ to Mn⁴⁺. While two pronounced D_Li minima at 4.7 V and 4.75 V are due to the oxidation of Ni²⁺/Ni³⁺ and Ni³⁺/Ni⁴⁺ respectively. The depletion of D_Li at the high voltage region is attributed to the occurrence of two successive phase transformation phenomena.

• Advances in nano research
• /
• v.13 no.3
• /
• pp.259-267
• /
• 2022

Two-dimensional (2D) transition metal carbides/nitrides or "MXenes" belong to a diverse-class of layered compounds, which offer composition- and electric-field-tunable electrical and physical properties. Although the majority of the MXenes, including Ti₃C₂T_x, are metallic, they typically show semiconductor-like behaviour in their percolated thin-film structure; this is also the most common structure used for fundamental studies and prototype device development of MXene. Magnetoconductance studies of thin-film MXenes are central to understanding their electronic transport properties and charge carrier dynamics, and also to evaluate their potential for spin-tronics and magnetoelectronics. Since MXenes are produced through solution processing, it is desirable to develop deposition strategies such as inkjet-printing to enable scale-up production with intricate structures/networks. Here, we systematically investigate the extrinsic negative magnetoconductance of inkjetprinted Ti₃C₂T_x MXene thin-films and report a crossover from weak anti-localization (WAL) to weak localization (WL) near 2.5K. The crossover from WAL to WL is consistent with strong, extrinsic, spin-orbit coupling, a key property for active control of spin currents in spin-orbitronic devices. From WAL/WL magnetoconductance analysis, we estimate that the printed MXene thin-film has a spin orbit coupling field of up to 0.84 T at 1.9 K. Our results and analyses offer a deeper understanding into microscopic charge carrier transport in Ti₃C₂T_x, revealing promising properties for printed, flexible, electronic and spinorbitronic device applications.

• Advances in materials Research
• /
• v.5 no.3
• /
• pp.181-192
• /
• 2016

In this work effect of high energy milling on the structural and electrical properties of $Ba(Fe_{1/2}Ta_{1/2})O_3$ (BFT) ceramic synthesized using standard solid-state reaction method were investigated. X-ray diffraction studies indicated that the unit cell structure for all the samples to be hexagonal (space group: P3m1). FTIR spectra also confirmed the formation of BFT without any new phase. The milled (10 h) BFT ceramic showed the formation of small grain sizes (<$2{\mu}m$) which is beneficial for dielectric applications in high density integrated devices. Besides, the milled (10 h) BFT ceramic sample exhibited superior dielectric properties (enhancement in ${\varepsilon}^{\prime}-value$ and reduction in $tg{\delta}-value$) compared to un-milled one. Impedance analysis indicated the negative temperature coefficient of resistance (NTCR) character. The correlated barrier hopping model (jump relaxation type) is found to successfully explain the mechanism of charge transport in present ceramic samples.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.19 no.1
• /
• pp.111-120
• /
• 2016

This study is aimed at using the grasped problems of protected areas in Korea as the basic data for management planning and system improvement of protected areas by grasping realistic problems through the interview with the persons in charge on the basis of general problems of domestic protected areas. To this end, this study deducted major problems in urgent need of improvement, and improvement direction through the survey of the persons in charge of protected areas. This study result is as follows: The major problems, which should be preferentially improved, were found to be shortages of management infrastructure, cooperation between interested parties, and threat factors in protected areas, etc. Such problems are interconnected with each other, thus coming up complexly; therefore, it's necessary to make a comprehensive approach to the problems after confirming the causal relationship of the identified problems. In addition, for the purpose of effective management of a protected area, it's necessary to implement priority management of major problems through different management intensity from the planning phase. Also, it's important to enhance the effectiveness of planning by considering a possible potential threat factor in the outside of protected areas, and referring to the contents of the development plan for the relevant area in time of management planning. Lastly, there is the need for systematic improvement of an institution through thorough status review of the actual state of management planning fulfillment in order to increase the effectiveness of planning in a follow-up study hereafter.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.4
• /
• pp.1105-1109
• /
• 2012

Breast cancer is the second most common cancer in women in India and the disease burden is increasing annually. The lack of awareness initiatives, structured screening, and affordable treatment facilities continue to result in poor survival. We present a breast cancer survival scenario, in urban population in India, where standardised care is distributed equitably and free of charge through an employees' healthcare scheme. We studied 99 patients who were treated at our hospital during the period 2005 to 2010 and our follow-up rates were 95.95%. Patients received evidence-based standardised care in line with the tertiary cancer centre in Mumbai. One-, three- and five-year survival rates were calculated using Kaplan-Meier method. Socio-demographic, reproductive and tumor factors, relevant to survival, were analysed. Mortality hazard ratios (HR) were calculated using Cox proportional hazard method. Survival in this series was compared to that in registries across India and discrepancies were discussed. Patients mean age was 56 years, mean tumor size was 3.2 cms, 85% of the tumors belonged to T1 and T2 stages, and 45% of the patients belonged to the composite stages I and IIA. Overall 5-year survival was 74.9%. Patients who presented with large-sized tumors (HR 3.06; 95% CI 0.4-9.0), higher composite stage (HR 1.91; 0.55-6.58) and undergone mastectomy (HR 2.94; 0.63-13.62) had a higher risk of mortality than women who had higher levels of education (HR 0.25; 0.05-1.16), although none of these results reached the significant statistical level. We observed 25% better survival compared to other Indian populations. Our results are comparable to those from the European Union and North America, owing to early presentation, equitable access to standardised free healthcare and complete follow-up ensured under the scheme. This emphasises that equitable and affordable delivery of standardised healthcare can translate into early presentation and better survival in India.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.9
• /
• pp.2679-2683
• /
• 2014

Mechanisms underlying the impacts of interactions between carbon nanoparticles (CNPs) and ionic liquids (ILs) on the physicochemical behavior of CNPs need to be more full worked out. This manuscript describes a theoretical investigation at multiple levels on the interactions of fullerene $C_{60}$ with 21 imidazolium-based ILs of varying alkyl side chain lengths and anionic types and their impacts on $C_{60}$ dispersion behavior. Results show that ${\pi}$-cation interaction contributed to mechanism of the $C_{60}$-IL interaction more than ${\pi}$-anion interaction. The calculated interaction energy ($E_{INT}$) indicates that $C_{60}$ can form stable complex with each IL molecule. Moreover, the direction of charge transfer occurred from IL to $C_{60}$ during the $C_{60}$-IL interaction. Quantitative models were developed to evaluate the self-diffusion coefficient of $C_{60}$ ($D_{fullerene}$) in bulk ILs. Three interpretative molecular descriptors (heat of formation, $E_{INT}$, and charge) that describe the $C_{60}$-IL interactions and the alkyl side chain length were found to be determinants affecting $D_{fullerene}$.

• Journal of Society of Preventive Korean Medicine
• /
• v.21 no.3
• /
• pp.11-18
• /
• 2017

Objectives : In an effort to suggest a developmental plan of Traditional Korean Medicine health promotion project(TKM-HPP), this study was conducted to identify the problems experienced by public health Traditional Korean Medicine(PH-TKM) doctors in duty and to analyze successful cases of the health promotion project. Methods : Two PH-TKM doctors in duty at the Public Health Centre branch and Public Health Centre respectively, and one TKM doctor in charge of Public Health Centre participated in the in-depth interview. The research procedure was as follows; 1) inform study objectives and interview questions to participants, 2) in-depth interview with semi-structured questions, and 3) post-confirmation and verification. The interview was recorded and transcripted. In-depth interview was composed of 6 subsections: 1) Introducing participants and share purpose of interview, 2) Confirmation of the job status and difficulty of public health centre, 3) Reflecting and sharing experiences of public health clinic job performance cases, 4) Current status and improvement needs of TKM-HPP, 5) Discussions on improvement of TKM-HPP in public health center, 6) Sharing and reconfirmation of interview results. Thematic analysis was conducted from the narratives. Results : The study showed that; 1) the support from the local government was critical for the successful TKM-HPP and participation of the PH-TKMs; 2) the major problems experienced by PH-TKMs were lack of training for TKM-HPP in the field and lack of knowledge at local government level; 3) the suggestions to provide PH-TKMs with manual to educate residents effectively and redefine roles of PH-TKMs in the project. It also suggests that TKM-HPP model should be developed by the district in a way of reflecting regional characteristics. Conclusions : Firstly, more efforts should be made on the projects rather than medical treatment in public health centers, except for areas where medical institutions are scarce. Secondly, in order to facilitate participation of PH-TKM doctors, each local office should reduce medical care and increase efforts related with projects. Thirdly, the institution has to develop feasible TKM-HPP plans that can be carried out by PH-TKMs by the manual. Lastly, pre-training should be provided to PH-TKMs to understand contents of TKM-HPP related to public health centre work before the placement.

• Journal of the Korean Chemical Society
• /
• v.58 no.2
• /
• pp.160-168
• /
• 2014

The electrochemical behavior and corrosion inhibition of zinc in 0.5 M $H_2SO_4$ in the absence and presence of some chromones has been investigated using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. The presence of these investigated compounds in the corrosive solutions decrease the weight loss, the corrosion current density, and double layer capacitance but increases the charge transfer resistance. Polarization studies were carried out at room temperature, and showed that all the studied compounds act as mixed type inhibitors with a slight predominance of cathodic character. The effect of temperature on corrosion inhibition has been studied and the thermodynamic activation and adsorption parameters were determined and discussed. The adsorption of the investigated compounds on zinc was found to obey Langmuir adsorption isotherm.