Proceedings of the National Academy of Sciences, India Section A: Physical Sciences最新文献

The research in spintronics aims to advance the present memory and computation technology by engaging the spin degree of electron. The use of femtosecond optical pulses is relevant, which has shown to trigger the fastest changes in the magnetic state of matter, leading to the possibility of high speed and energy efficient opto-spintronic memory. In the past decade, the prospects of ultrafast opto-magnetic control in different materials were explored, leading to the discovery of all optical switching of magnetization, which showed promise for applications in technology as well as improved the fundamental understanding of light–spin interaction on ultrashort timescale. In this review, we presented the recent developments, advances and emerging research directions in optical control of magnetization, with an emphasis on the qualitative understanding of the physical processes involved under transient nonequilibrium state. Finally, we outlined the potential of integration of all optical magnetization switching with magnetic random access memory and other memory applications as least-dissipative and fastest method for magnetic writing.

In this study, by introducing the concepts of asymptotical lacunary statistical and asymptotical strong p-lacunary equivalence of order (eta ) ((0<eta le 1)) in the Wijsman sense for double set sequences, some properties of these concepts are examined and also the relationship between these concepts is mentioned. Moreover, the relationships between these concepts and the asymptotical equivalence concepts previously given for double set sequences are investigated.

This study assesses land use and land cover (LULC) dynamics and their impacts in the Alwero watershed, in western Ethiopia. LULC datasets were created from Landsat imagery from 1973, 1987, 2002, and 2020 using ArcGIS 10.7® software. Results show that forest cover decreased from 52 to 30% between 1973 and 2020, mainly due to the expansion of cultivated land (small and large farms). Between 1973 and 2020, the number of small farms increased from 7.4 to 13.2%, with a net decrease in bare land (74.2%), grassland (19.7%), and forest (2.6%). Large farms increased from 1.5 to 7.2% between 2002 and 2020, with a net decrease in fallow (44%) and natural vegetation (19.4%). Fallow land shows a decreasing trend from 28% (1973) to 13% (2020), due to increased conversion to small farms (35.0%) and large farms (20.1%). The main causes of the changes are the rapid population growth and the large scale agricultural investments in the region. The deterioration of local people's living conditions and deforestation are the main impacts of LULC change in the study area. The innovative element of this study is the production of maps for large and small farms separately, which is useful for making decisions related to problems of large agricultural land investments (LALIs). The study concludes that the continued loss of forests will affect the government's development vision in general and mitigation of the negative impacts of climate change and climate variability in particular.

In this paper, we present the notions of Wijsman strongly ideal (r-)deferred Cesàro summability and Wijsman (mu )-deferred Cesàro I-statistical convergence of order (a, b) allied with modulus function f for a sequence of closed sets of a separable metric space ((mathcal {X},rho )). We also define their respective sequence spaces ( left[ {{text{DC}}left[ {p,q} right]_{W}^{{(a,b)}} (r,f)} right]^{I} ) and ( left[ {_{mu } {text{DS}}left[ {p,q} right]_{W}^{{(a,b)}} left( f right)} right]^{I} ), respectively. We also prove that for (ale b), the newly formed sequence space is well defined but for ( a>b ), foresaid space is not well defined in general. Some inclusion relation-based results are also established with some counterexamples to support our results. At last, it is shown that if a bounded sequence of closed sets is Wijsman (mu )-deferred Cesàro I-statistical convergence of order (a, b), then it need not be Wijsman strongly ideal (r-)deferred Cesàro summable.

Qualitative and quantitative analyses of nutritional supplements and adulteration/toxic elements present in various tea leaves have been performed and compared. Rapid identification of inorganic (i.e., Ca, K, Na, Mg, Ba, Al, Sr, Mn) and organic (C, N, O, H) elements have been done using laser-induced breakdown (LIB) spectra of tea leaves. The electronic bands of the metal oxides (CaO, BaO, SrO, and AlO) are also identified. Molecular bands of CN and C₂ molecules in the LIB spectra show the presence of organic compounds in the tea samples. The concentration of the constituents of the tea samples has been determined using the calibration free (CF-LIBS) technique and results are further compared with results obtained by energy-dispersive X-ray (EDX) technique. The toxicity of the various tea leaves has been discussed based on the contents of Ba, Al, and Sr in each sample. The quantitative analysis of Na, K, and Mg may be helpful to control hypertension and chronic kidney disease. Principal component analysis (PCA) classifies the different samples based on their elemental constituents. In all tea leaves samples, the presence of amino acids, enzymes, pigments, carbohydrates, caffeine and nicotine has been established via photoacoustic spectroscopy (PAS). Further, the confirmation of the molecular bands of the tea leaves is done with (Fourier Transform Infrared) FTIR spectroscopic technique.

In this paper, we introduce a new class of set in ideal tritopological spaces which is called (i, j, k)-semi-I-open set. Besides, we study some of its properties. Moreover, we define the notion of (i, j, k)-semi-I-continuous functions and we show some of their properties and characterizations.

In this paper we define the projective action of the Lie group (textrm{SL}(3;mathbb {R})) on (mathbb{R}mathbb{P}^2). We have considered all the one-parameter subgroups (up to conjugacy) of (textrm{SL}(3;mathbb {R})) and constructed their orbits in two-dimensional homogeneous space by defining the projective action. We obtain the underlying geometry under this action of (textrm{SL}(3;mathbb {R})) by finding the corresponding invariant projective properties. We also discuss whether the action of (textrm{SL}(3;mathbb {R})) is triply transitive and to find the possible fixed points under the action.

Plastics are commonly occurring in the marine environments. The presence of microplastics in most habitats in the open ocean, seas, beaches, surface waters, the water column and in Deep Ocean is recently reported in freshwater systems. The present review mainly focussed on the microplastics distribution and its impacts in India with special reference to plastic pollution in Indian Ocean and major nine coastal states of India. In India, microplastics pollution research along the Indian coastline and its impacts on the marine living organisms is poorly studied. Very few studies along the beaches of Indian coast have been carried out on the distribution pattern of microplastics. The occurrence of plastics in Indian Ocean and the potential impacts to the marine organisms are growing concerns. In India, Maharashtra, Gujarat and Tamil Nadu have conducted the awareness programmes for the plastic usage and control measures for better way to use recycle or degrade the plastic material and otherwise use clothes materials for different needful purposes. The existing knowledge about the plastic pollution and its impacts have created the awareness for industrialists, consumers and policy makers to develop the significant technological policy solutions to replace the plastics.