Enhanced Raman and photoluminescence response in monolayer MoS2_2 due to laser healing of defects

Bound quasiparticles, negatively charged trions and neutral excitons, are associated with the direct optical transitions at the K-points of the Brillouin zone for monolayer MoS$_2$. The change in the carrier concentration, surrounding dielectric constant and defect concentration can modulate the photoluminescence and Raman spectra. Here we show that exposing the monolayer MoS$_2$ in air to a modest laser intensity for a brief period of time enhances simultaneously the photoluminescence (PL) intensity associated with both trions and excitons, together with $\sim$ 3 to 5 times increase of the Raman intensity of first and second order modes. The simultaneous increase of PL from trions and excitons cannot be understood based only on known-scenario of depletion of electron concentration in MoS$_2$ by adsorption of O$_2$ and H$_2$O molecules. This is explained by laser induced healing of defect states resulting in reduction of non-radiative Auger processes. This laser healing is corroborated by an observed increase of intensity of both the first order and second order 2LA(M) Raman modes by a factor of $\sim$ 3 to 5. The A$_{1g}$ mode hardens by $\sim$ 1.4 cm$^{-1}$ whereas the E$^1_{2g}$ mode softens by $\sim$ 1 cm$^{-1}$. The second order 2LA(M) Raman mode at $\sim$ 440 cm$^{-1}$ shows an increase in wavenumber by $\sim$ 8 cm$^{-1}$ with laser exposure. These changes are a combined effect of change in electron concentrations and oxygen-induced lattice displacements.Comment: 15 pages, 5 figures, Journal of Raman Spectroscopy, 201

Symmetry-dependent phonon renormalization in monolayer MoS2 transistor

Strong electron-phonon interaction which limits electronic mobility of semiconductors can also have significant effects on phonon frequencies. The latter is the key to the use of Raman spectroscopy for nondestructive characterization of doping in graphene-based devices. Using in-situ Raman scattering from single layer MoS$_2$ electrochemically top-gated field effect transistor (FET), we show softening and broadening of A$_{1g}$ phonon with electron doping whereas the other Raman active E$_{2g}^{1}$ mode remains essentially inert. Confirming these results with first-principles density functional theory based calculations, we use group theoretical arguments to explain why A$_{1g}$ mode specifically exhibits a strong sensitivity to electron doping. Our work opens up the use of Raman spectroscopy in probing the level of doping in single layer MoS$_2$-based FETs, which have a high on-off ratio and are of enormous technological significance.Comment: 5 pages, 3 figure

Effect of Aerobic Training on Percentage of Body Fat and Resting Heart Rate among College Obese Women

The aim of the present research was to determine the effect of aerobic training on percentage body fat and resting heart rate among obese women. For this purpose twenty (20) female obese samples (age 17-25) were selected. The subjects were given endurance training for only one session in the morning between 6 am and 7 am for three alternate days a week for six weeks. To analyse the collected data,„t? ratio was used at 0.05level of confidence. The results showed that there was a significant decrease in the percentage of body fat but no changes is elicited on resting heart rate. It was concluded that the aerobic training is widely believed to induce changes in the percentage body fat among obese women

An impact of age, birth order and qualification on women in sports participation levels in Tamilnadu and Pondicherry

The position, a child had by the order of birth significantly affected the child’s growth and personality.  Research in the late twentieth century and early twenty-first century shows even greater influence, contributing to intelligence, career choice, and to a certain degree, success in adulthood. Until the independence of India, The present research is to examine whether the age, order of birth and qualification of women have any impact on women's participation in sports among Tamil Nadu and Pondicherry at different levels. Sixty women players were randomly selected from 4 Colleges of two different states. First half from Cuddalore, Tamil Nadu state and second half from Karaikal, Pondicherry state. The selected subjects were with a brief questionnaire, to find out their level of sports participation, age, order of birth and qualification. Data obtained were subjected to find out statistical significance among the means using 3 (levels - district, state and national participations) x 2 (states -Tamil Nadu and Pondicherry) Factorial analysis. The results proved that there were significant differences in age and qualifications of the different level of women players. There was no significant difference among the states, Tamil Nadu and Pondicherry in age, order of birth and qualifications of the women players. It was concluded that age and qualification play vital role in the participation level of women players

An evaluvation of the self-esteem of women sports participant in various games

The present study was conducted in Tamil Nadu state, India with the objective of studying self-esteem of women sports participant in different games.  Exploratory research design was adopted for the study.  The total sample comprised of 90 playing women in which 30 were Kho - Kho / Kabaddi players, 30 were Badminton / Ball Badminton / Volley Ball players and 30 were Squash Rackets / Table Tennis / Fencing / Tennis players.  Self esteem scale developed by Verma and Kapadia was used to collect the data.  The investigators personally met the respondents by going to their place and administered the tests and collected the data.  Among all the three categories of women sports participants, the Squash Rackets / Table Tennis / Fencing / Tennis were having high level of self esteem followed by Badminton / Ball Badminton and Kho - Kho / Kabaddi players.  Collectively as one group, most of them were having high and medium level of self esteem reflecting that sports performance of women promotes esteem of women.  Through correlation it was found that education and playing experience were significantly and positively related to self esteem of women sports participants.  Hence women with higher education and higher playing experience had higher self esteem

Sharp Raman Anomalies and Broken Adiabaticity at a Pressure Induced Transition from Band to Topological Insulator in Sb2Se3

The nontrivial electronic topology of a topological insulator is thus far known to display signatures in a robust metallic state at the surface. Here, we establish vibrational anomalies in Raman spectra of the bulk that signify changes in electronic topology: an E2 g phonon softens unusually and its linewidth exhibits an asymmetric peak at the pressure induced electronic topological transition (ETT) in Sb2Se3 crystal. Our first-principles calculations confirm the electronic transition from band to topological insulating state with reversal of parity of electronic bands passing through a metallic state at the ETT, but do not capture the phonon anomalies which involve breakdown of adiabatic approximation due to strongly coupled dynamics of phonons and electrons. Treating this within a four-band model of topological insulators, we elucidate how nonadiabatic renormalization of phonons constitutes readily measurable bulk signatures of an ETT, which will facilitate efforts to develop topological insulators by modifying a band insulator

ICKSC :An Efficient Methodology for Predicting Kidney Stone From CT Kidney Image Dataset using Conventional Neural Networks

Chronic Kidney Diseases (CKD) has become one among the world wide health crisis and needs the associated efforts to prevent the complete organ damage. A considerable research effort has been put forward onto the effective separation and classification of kidney Stones from the kidney CT Images. Emerging machine learning along with deep learning algorithms have waved the novel paths of kidney stone detections. But these methods are proved to be laborious and its success rate is purely depends on the previous experiences. To achieve the better classification of kidney stone, this paper proposes a novel Intelligent CNN based Kidney Stone Classification (ICKSC) system which is based on transfer learning mechanism and incorporates 8 Layered CNN, densenet169_model, mobilenetv2_model, vgg19_model and xception_model. The extensive experimentation has been conducted to evaluate the efficacy of the recommended structure and matched with the other prevailing hybrid deep learning model. Experimentation demonstrates that the suggested model has showed the superior predominance over the other models and exhibited better performance in terms of training loss, accuracy, recall and precision

Indian Sign Language Recognition through Hybrid ConvNet-LSTM Networks

Dynamic hand gesture recognition is a challenging task of Human-Computer Interaction (HCI) and Computer Vision. The potential application areas of gesture recognition include sign language translation, video gaming, video surveillance, robotics, and gesture-controlled home appliances. In the proposed research, gesture recognition is applied to recognize sign language words from real-time videos. Classifying the actions from video sequences requires both spatial and temporal features. The proposed system handles the former by the Convolutional Neural Network (CNN), which is the core of several computer vision solutions and the latter by the Recurrent Neural Network (RNN), which is more efficient in handling the sequences of movements. Thus, the real-time Indian sign language (ISL) recognition system is developed using the hybrid CNN-RNN architecture. The system is trained with the proposed CasTalk-ISL dataset. The ultimate purpose of the presented research is to deploy a real-time sign language translator to break the hurdles present in the communication between hearing-impaired people and normal people. The developed system achieves 95.99% top-1 accuracy and 99.46% top-3 accuracy on the test dataset. The obtained results outperform the existing approaches using various deep models on different datasets

Phonon Anomalies, Orbital-Ordering and Electronic Raman Scattering in iron-pnictide Ca(Fe0.97Co0.03)2As2: Temperature-dependent Raman Study

We report inelastic light scattering studies on Ca(Fe0.97Co0.03)2As2 in a wide spectral range of 120-5200 cm-1 from 5K to 300K, covering the tetragonal to orthorhombic structural transition as well as magnetic transition at Tsm ~ 160K. The mode frequencies of two first-order Raman modes B1g and Eg, both involving displacement of Fe atoms, show sharp increase below Tsm. Concomitantly, the linewidths of all the first-order Raman modes show anomalous broadening below Tsm, attributed to strong spin-phonon coupling. The high frequency modes observed between 400-1200 cm-1 are attributed to the electronic Raman scattering involving the crystal field levels of d-orbitals of Fe2+. The splitting between xz and yz d-orbital levels is shown to be ~ 25 meV which increases as temperature decreases below Tsm. A broad Raman band observed at ~ 3200 cm-1 is assigned to two-magnon excitation of the itinerant Fe 3d antiferromagnet.Comment: Accepted for Publication in JPC