The Cuddapah Basin in southern India has a potential for uranium mineralization due to some favorable factors such as its temporal, stratigraphic and tectonic settings. Systematic exploration program conducted by the ...The Cuddapah Basin in southern India has a potential for uranium mineralization due to some favorable factors such as its temporal, stratigraphic and tectonic settings. Systematic exploration program conducted by the Atomic Minerals Directorate for Exploration and Research (AMD) within the Cuddapah Basin resulting in the recognition of distinct types of uranium mineralization, viz., strata bound type, fracture/shear-controlled type and tabular type. The Gulcheru Formation which is the lowermost unit of the Cuddapah Basin is dominantly arenitic in nature. During the exploration works, a number of uranium anomalies were identified with dimensions ranging from 1 m to 1.5 km. Gulcheru quartzite hosted uranium mineralization is intermittent and inconsistent in nature. The anomalous outcrops are distributed over a strike length of ca. 60 km between Gandi in the SE and Ambakapallein the NW. Presently, two different types of uranium mineralization are characterized on the basis of field observations, mapping and structural interpretation, petro-mineralogy and geochemistry. Although the host rock is same for both types, the mechanism of uranium enrichment is totally different. The Ambakapalle uranium mineralization is controlled by fault zone and associated hydrothermal activity. Whereas, the Tummalapalle uranium mineralization is litho-controlled in nature influenced by suitable four ‘P’ factors, i.e., provenance, porositypermeability, precipitation and preservation. The geochemical characterization of Gulcheru quartzite suggest a passive margin type of provenance setting. Petro-mineralogically the quartz arenite suggests enough textural as well as mineralogical maturity. Ambakapalle quartzite is slightly strained and deformed due to faulting. Analysis of selected samples recorded 0.01% to 0.048% U3O8 and <0.01% ThO2. Petrographic observation revealed that the anomalies were appeared due to secondary uranium minerals occurring as surficial encrustations, fracture filling and lesser irregular patches. Structural analysis suggests the mineralization along E-W trace slip fault is possibly consistent in sub-surface. Tummalapalle quartzite is relatively less deformed arenitic in nature with significant enrichment in MREE. The genetic models for the two types of mineralization is totally different.展开更多
In this work,the effects of the methane gas flow and the internal oscillating electric field between electrodes on radio-frequency(RF)atmospheric pressure argon/methane plasma jet and process of diamond-like carbon(DL...In this work,the effects of the methane gas flow and the internal oscillating electric field between electrodes on radio-frequency(RF)atmospheric pressure argon/methane plasma jet and process of diamond-like carbon(DLC)film deposition have been investigated.Properties of RF atmospheric Ar/methane plasma jet such as active species density,length,electron temperature,appearance and ionization process of argon/methane plasma jet are changed due to the changing of methane flow content and electric field vector and its gradient.With increasing methane flow,the formation of C2 hydrocarbon and CH band content is decreased because injected electrical energy to a mixture of Ar/methane gases is insufficient to stabilize the ionization process of methane gas and the electrical-chemical reaction rate is decreased.With shortening the gas gap between two electrodes,electric field strength and its gradient are increased leading to more energy injection to the electron.Electrical-chemical reactions are strengthened leading to increasing the CH band content.These phenomena introduce the Ar/methane plasma jet in different modes causing to deposit the DLC film with different structures and properties.With using quartz glass and alumina ceramic as dielectric barriers tubes,RF atmospheric pressure Ar/methane plasma jet has been used to deposit DLC coating in different modes.Increasing methane content and shortening the gas gap leads to decreasing sp3 bonded content and the quality of the deposited film.展开更多
We theoretically analyze the transient properties of a probe field absorption and dispersion in a coupled semiconductor double-quantum-dot nanostructure.We show that in the presence of the Gaussian laser beams,absorpt...We theoretically analyze the transient properties of a probe field absorption and dispersion in a coupled semiconductor double-quantum-dot nanostructure.We show that in the presence of the Gaussian laser beams,absorption and dispersion of the probe field can be dramatically influenced by the relative phase between applied fields and intensity of the Gaussian laser beams.Transient and steady-state behaviors of the probe field absorption and dispersion are discussed to estimate the required switching time.The estimated range is between 5-8 ps for subluminal to superluminal light propagation.展开更多
Plate tectonic activity has played a critical role in the development of petrotectonic associations in the Kadiri schist belt. The calc alkaline association of basalt, andesite, dacite and rhyolite (BADR) is the sig...Plate tectonic activity has played a critical role in the development of petrotectonic associations in the Kadiri schist belt. The calc alkaline association of basalt, andesite, dacite and rhyolite (BADR) is the signature volcanic rock suite of the convergent margin. The N-S belt has gone below the unconformity plane of Cuddapah sediments. In the northern part geochemical and structural attributes of the Kadiri greenstone belt is studied along with microscopic observations of selected samples. Harker diagram plots of major elements generally indicate a liquid line of descent from a common source, such that BADR rocks are derived from a common parent magma of basaltic to andesitic composition. These calc-alkaline volcanic rocks are formed at convergent margins where more silicic rocks represent more highly fractionated melt. All the litho-units of this greenstone belt indicate crush and strain effects. The stretched pebbles in the deformed volcanic matrix with tectonite development along with associated greenschist facies metamorphism, alteration and hydration is remarkable. Flow foliation plane with N-S strike and very low angle (5~ to 10~) easterly dip and N-S axial planar schistosity formed due to later phase isoclinal folding can be clearly identified in the field. Basic intrusives are quite common in the surrounding area. All the observations including the field setting and geochemistry clearly demonstrate ocean-continent subduction as the tectonic environment of the study area.展开更多
In fast reactors, the inherent neutron source strength is often insufficient for monitoring the reactor start-up operation with ex-core detectors. To increase the subcritical neutron flux, an auxiliary neutron source ...In fast reactors, the inherent neutron source strength is often insufficient for monitoring the reactor start-up operation with ex-core detectors. To increase the subcritical neutron flux, an auxiliary neutron source subassembly(SSA) is generally used to overcome this problem. In this study, the estimated neutron source strength and detector count rate of an antimony-beryllium-based SSA are obtained using the deterministic transport code DORT and Monte Carlo calculations. Because the antimony activation rate is a critical parameter, its sensitivity to the capture cross section and neutron flux spectrum is studied. The reaction cross section sensitivity is studied by considering data from different evaluated nuclear data files.It is observed that, because of the variation in the cross sections from different evaluated nuclear data files, the values of the saturation gamma(> 1.67 MeV) activity and neutron strength predicted by ORIGEN2 lie within ±2%.The obtained antimony activation rate and sensitivity to the neutron flux are partially validated by irradiating samples of antimony in the KAMINI reactor. The average onegroup capture cross sections of bare and cadmium-covered 123Sb samples obtained by the ratio method are 4.0 and 1.78 b, respectively. The results of the calculation predicting the activated neutron source strength as a function of operating time and sensitivity to the neutron spectrum in the irradiation region are also presented.展开更多
The current sheath velocity in 0.25 Torr gas pressure of Filippov type plasma focus is studied experimentally. By using two tridimensional magnetic probes on top of the anode surface, the current sheath velocity is me...The current sheath velocity in 0.25 Torr gas pressure of Filippov type plasma focus is studied experimentally. By using two tridimensional magnetic probes on top of the anode surface, the current sheath velocity is measured for argon, oxygen and nitrogen. Additionally, the effect of charging voltage on the current sheath velocity is studied in both axial and radial phases. We found that, the maximum current sheath velocities at both radial and axial phases are respectively 4.33 ± 0.28 (cm/μs) and 3.92 ± 0.75 (cm/μs) with argon as the working gas at 17 kV. Also, the minimum values of current sheath velocity are 1.48 ± 0.15 (cm/μs) at the radial phase and 1.14 ± 0.09 (cm/μs) at the axial phase with oxygen at 12 kV. The current sheath velocity at the radial phase is higher than that at the axial phase for all gases and voltages. In this study, variation of the full width half maximum (FWHM) of magnetic probe signals with voltage is investigated for different gases at radial and axial phases.展开更多
Iron irrespective of its valency states forms bluish 1:1 cationic, bluish-violet 1:3 neutral and purple 1:3 anionic complexes with 2,3-dihydroxynaphthalene, at pH 2 - 3, 4 - 5 and 8 - 10, respectively. The cationic bl...Iron irrespective of its valency states forms bluish 1:1 cationic, bluish-violet 1:3 neutral and purple 1:3 anionic complexes with 2,3-dihydroxynaphthalene, at pH 2 - 3, 4 - 5 and 8 - 10, respectively. The cationic bluish complex is highly insensitive and not extractable in organic solvents. Similarly, the bluish violet 1:3 neutral complex is of moderate sensitivity, and it is extractable in organic solvents with reduced sensitivity. The purple 1:3 anionic complex is as such not extractable in any organic solvents. However, in the surfactant medium of the cationic surfactant, cetyltrimethylammonium bromide it is extractable in organic solvents with enhanced sensitivity. The 1:3 anionic complex which is extractable in organic solvents as an ion associate in the presence of cetyltrimethyl ammonium bromide is chosen for application to Silicate rocks, Minerals, Soils, Stream sediments, Concentrates, Tobacco leaves, Cigarettes and Waters, for accurate and sensitive determination of iron owing to facile extraction of iron, enhanced sensitivity high selectivity and better reproducibility of results. The present paper describes a systematic study on the development of an extraction spectrophotometric method for the determination of iron in samples of diverse matrices.展开更多
Amplifying the attosecond pulse by the chirp pulse amplification method is impossible. Furthermore, the intensity of attosecond pulse is low in the interaction of laser pulse and underdense plasma. This motivates us t...Amplifying the attosecond pulse by the chirp pulse amplification method is impossible. Furthermore, the intensity of attosecond pulse is low in the interaction of laser pulse and underdense plasma. This motivates us to propose using a multi-color pulse to produce the high intense attosecond pulse. In the present study, the relativistic interaction of a three-color linearly-polarized laser-pulse with highly overdense plasma is studied. We show that the combination of ω1, ω2 and ω3 frequencies decreases the instance full width at half maximum reflected attosecond pulse train from the overdense plasma surface. Moreover, we show that the three-color pulse increases the intensity of generated harmonics, which is explained by the relativistic oscillating mirror model. The obtained results demonstrate that if the three-color laser pulse interacts with overdense plasma, it will enhance two orders of magnitude of intensity of ultra short attosecond pulses in comparison with monochromatic pulse.展开更多
In this work, the effect of electrical discharge on nitrate concentration is considered in aqueous solution. The atmospheric pressure plasma was produced by a high-voltage power supply at 27 k Hz using pin-to-pin conf...In this work, the effect of electrical discharge on nitrate concentration is considered in aqueous solution. The atmospheric pressure plasma was produced by a high-voltage power supply at 27 k Hz using pin-to-pin configuration. Air, argon,and argon/methane mixture were used to study the working gas effect. UV-VIS spectroscopy and ion chromatography were used to analyze the effect of the electrical discharge on nitrate concentration in deionized water. Optical emission spectroscopy(OES) was applied to diagnose active species inside and on the surface of the deionized water solution. The results of the present work showed that the atmospheric pressure electric discharge with air increases nitrate concentration while it remains constant using argon and argon/methane electrical discharges. It was also revealed that in the presence of air, the electrical discharge reduces p H, acidifying the solution and increasing solution conductivity due to production of extra nitrate ions. On the other hand, argon electrical discharge increases p H and conductivity due to production of OHion in water.展开更多
Realizing media independence in today’s communication system remains an open problem by and large.Information retrieval,mostly through the Internet,is becoming the most demanding feature in technological progress and...Realizing media independence in today’s communication system remains an open problem by and large.Information retrieval,mostly through the Internet,is becoming the most demanding feature in technological progress and this web-based data access should ideally be in user-selective form.While blind-folded access of data through the World Wide Web is quite streamlined,the counter-half of the facet,namely,seamless access of information database pertaining to a specific end-device,e.g.robotic systems,is still in a formative stage.This paradigm of access as well as systematic query-based retrieval of data,related to the physical enddevice is very crucial in designing the Internet-based network control of the same in real-time.Moreover,this control of the end-device is directly linked up to the characteristics of three coupled metrics,namely,‘multiple databases’,‘multiple servers’and‘multiple inputs’(to each server).This triad,viz.database-input-server(DIS)plays a significant role in overall performance of the system,the background details of which is still very sketchy in global research community.This work addresses the technical issues associated with this theology,with specific reference to formalism of a customized DIS considering real-time delay analysis.The present paper delineates the developmental paradigms of novel multi-input multioutput communication semantics for retrieving web-based information from physical devices,namely,two representative robotic sub-systems in a coherent and homogeneous mode.The developed protocol can be entrusted for use in real-time in a complete user-friendly manner.展开更多
Ozone plays a significant part in regulating climate change and the chemical characteristics of the atmosphere. Changes in atmospheric ozone can be studied in more detail using ground-based and satellite-based instrum...Ozone plays a significant part in regulating climate change and the chemical characteristics of the atmosphere. Changes in atmospheric ozone can be studied in more detail using ground-based and satellite-based instruments. Studies on the long-term global changes in total column ozone have begun more than three-decade ago using satellite data. The main objective of this work is to analyze the Total Column Ozone (TCO) variations, and tropo-spheric ozone variations over different twenty locations in the Indian sub-continent by using Total Ozone Mapping Spectrometer (TOMS) and AURA OMI/MLS data. The long-term analysis of total column ozone is divided into two phases (1979-1994 and 2005-2018), and tropospheric ozone for one phase (2005-2018) in order to detect changes in the ozone trend pattern. The results of linear regression analysis show a declining trend of total column ozone, and an increasing trend of tropospheric ozone over the selected locations. The impact of wind pattern on the variation of ozone has been analyzed by using NCEP reanalysis data, and found that wind patterns played a prominent role in spatial and temporal changes in total and tropospheric ozone distribution over the subcontinent. Latitudinal variation of total column ozone from Nagarcoil to Anantanag has also been studied for the years 1979, 1994, 2005, and 2018, which indicates an increase in ozone concentration with latitude.展开更多
Seaweed is an enormous resource comprised with natural bioactive compounds with several therapeutic effects including anticancer activity.In this context,the biochemical composition of seaweed plays a major role.Many ...Seaweed is an enormous resource comprised with natural bioactive compounds with several therapeutic effects including anticancer activity.In this context,the biochemical composition of seaweed plays a major role.Many biochemical compounds isolated from seaweed,fractions of seaweed and crude extracts has revealed ability of seaweed to fight against several cancer types.In this contrast seaweed extracts inhibit cancer cell growth and proliferation by inducing apoptosis and by inhibiting metastasis activity.In this review,biochemical and anticancer properties of seaweeds are discussed and this will provide the basic information to develop a novel chemotherapeutic drug to challenge the cancers.展开更多
Cilia and flagella are organelles of motility that enable cells to swim or move liquid over its surface. An exhaustive literature survey for the presence of the organelle in organisms across phyla showed that most ani...Cilia and flagella are organelles of motility that enable cells to swim or move liquid over its surface. An exhaustive literature survey for the presence of the organelle in organisms across phyla showed that most animal cells harbor cilia in contrast to very few fungal cells. While this was not unexpected, it was the position and arrangement of this organelle in each cell that intrigued our attention. Natural selection might have favored motility over chemotaxis;and it would have done so to evolve a stable structure that could have undergone an optimization process requiring a precise geometry in the shape of cells and the structure that would help cells to move. The positioning of such a structure would play a pre-dominant role in optimal motility. It is now known that the flagellar position of a cell is a genetically distinct trait, occasionally used in phylogeny of bacteria, distributed in distinguishing patterns over cellular surface, but basically are of two types, either polar (one flagellum arising from one pole per cell) or peritrichous (lateral flagella distributed over the entire cell surface). Irrespective of the cellular habitat, flagella origin, ultrastructure and proteome, the present investigation surveyed 26 sub-types of flagellar arrangements from as many species as possible. A peculiar pattern ensued-Prokaryotes harbored predominantly polar and peritrichous types;eukaryotes showed a mere change of the peritrichous one. These numbers when used to create a Similarity tree depicted a similarity distance of 14 between the Eubacteria and Archaebacteria forming the first neighborhood;Protozoans, Algae, Fungi, Plantae and Animalia formed a second neighborhood. We offer a working hypothesis for this pattern and the gradual shift in the flagellar arrangement from polar, peritrichous, sub-apical, and apical to lateral throughout evolution.展开更多
Point defect research in semiconductors has gained remarkable new momentum due to the identification of special point defects that can implement qubits and single photon emitters with unique characteristics.Indeed,the...Point defect research in semiconductors has gained remarkable new momentum due to the identification of special point defects that can implement qubits and single photon emitters with unique characteristics.Indeed,these implementations are among the few alternatives for quantum technologies that may operate even at room temperature,and therefore discoveries and characterization of novel point defects may highly facilitate future solid state quantum technologies.First principles calculations play an important role in point defect research,since they provide a direct,extended insight into the formation of the defect states.In the last decades,considerable efforts have been made to calculate spin-dependent properties of point defects from first principles.The developed methods have already demonstrated their essential role in quantitative understanding of the physics and application of point defect qubits.Here,we review and discuss accuracy aspects of these novel ab initio methods and report on their most relevant applications for existing point defect qubits in semiconductors.We pay attention to the advantages and limitations of the methodological solutions and highlight additional developments that are expected in the near future.Moreover,we discuss the opportunity of a systematic search for potential point defect qubits,as well as the possible development of predictive spin dynamic simulations facilitated by ab initio calculations of spin-dependent quantities.展开更多
Highly correlated orbitals coupled with phonons in two-dimension are identified for paramagnetic and optically active boron vacancy in hexagonal boron nitride by first principles methods which are responsible for rece...Highly correlated orbitals coupled with phonons in two-dimension are identified for paramagnetic and optically active boron vacancy in hexagonal boron nitride by first principles methods which are responsible for recently observed optically detected magnetic resonance signal.Here,we report ab initio analysis of the correlated electronic structure of this center by density matrix renormalization group and Kohn-Sham density functional theory methods.By establishing the nature of the bright and dark states as well as the position of the energy levels,we provide a complete description of the magneto-optical properties and corresponding radiative and non-radiative routes which are responsible for the optical spin polarization and spin dependent luminescence of the defect.Our findings pave the way toward advancing the identification and characterization of room temperature quantum bits in two-dimensional solids.展开更多
An idea of the surface plasmon resonance(SPR)has been utilized for the design of highly sensitive sensors based on the wagon-wheel fiber technology.Such sensors are sensitive to changes in the refractive index of samp...An idea of the surface plasmon resonance(SPR)has been utilized for the design of highly sensitive sensors based on the wagon-wheel fiber technology.Such sensors are sensitive to changes in the refractive index of sample analyte.In this study,a three-strut wagon-wheel structure,coated with the gold layer of nano-sized thickness,has been proposed as the SPR sensor.Finite element method is employed to simulate and tune the proposed SPR's design,which leads to a highly sensitive and multichannel plasmonic sensor with the ability for a dual reading on a single analyte or simultaneous identification of two analytes.In this design,suitable thickness values for the gold layer and core struts are determined.Sensitivities of the detector due to the first resonance peak, second resonance peak,and the difference in resonance peaks are calculated to be 1120nm/RIU, 1540nm/RIU,and 420nm/RIU,respectively,when analytes are placed in all three channels of the fiber.Sensitivity of the detector with respect to the second resonant peak for analyte in Channels 2 and 3 is also found to be 1252nm/RIU when Channel 1 is filled with the reference.The sensitivity and resolution of the sensor increase as the refractive index of the analyte increases by almost a linear proportion.If the sensor is utilized to detect the difference in two peaks,it would substantially reduce the noise,and the best result is expected.The thicknesses of the struts and the gold layer are proper parameters to be tuned in designing the detector.展开更多
The NOT gate that flips a classical bit is ubiquitous in classical information processing.However its quantum analogue,the universal NOT(UNOT) gate that flips a quantum spin in any alignment into its antipodal counter...The NOT gate that flips a classical bit is ubiquitous in classical information processing.However its quantum analogue,the universal NOT(UNOT) gate that flips a quantum spin in any alignment into its antipodal counterpart is strictly forbidden.Here we explore the connection between this discrepancy and how UNOT gates affect classical and quantum correlations.We show that while a UNOT gate always preserves classical correlations between two spins,it can non-locally increase or decrease their shared discord in ways that allow violation of the data processing inequality.We experimentally illustrate this using a multi-level trapped ^(171)Yb^+ ion that allows simulation of anti-unitary operations.展开更多
An experiment aimed to investigate the two-proton(2p) decay of the previously unknown nucleus ^(30)Ar was performed at GSI. By tracking the decay products in-flight with silicon micro-strip detectors, the 2p decays of...An experiment aimed to investigate the two-proton(2p) decay of the previously unknown nucleus ^(30)Ar was performed at GSI. By tracking the decay products in-flight with silicon micro-strip detectors, the 2p decays of ^(30)Ar were observed for the first time. For the calibration purpose, 2p decays of ^(19)Mg were also remeasured by tracking the coincident ^(17)Ne+p+p trajectories. By comparing the measured angular p-17 Ne correlations with those obtained from the corresponding Monte Carlo simulations,the simultaneous 2p decay of ^(19)Mg ground state and the sequential 2p emission of several known excited states of ^(19)Mg were confirmed. One new excited state in ^(19)Mg and two new excited states in ^(18)Na were observed.展开更多
文摘The Cuddapah Basin in southern India has a potential for uranium mineralization due to some favorable factors such as its temporal, stratigraphic and tectonic settings. Systematic exploration program conducted by the Atomic Minerals Directorate for Exploration and Research (AMD) within the Cuddapah Basin resulting in the recognition of distinct types of uranium mineralization, viz., strata bound type, fracture/shear-controlled type and tabular type. The Gulcheru Formation which is the lowermost unit of the Cuddapah Basin is dominantly arenitic in nature. During the exploration works, a number of uranium anomalies were identified with dimensions ranging from 1 m to 1.5 km. Gulcheru quartzite hosted uranium mineralization is intermittent and inconsistent in nature. The anomalous outcrops are distributed over a strike length of ca. 60 km between Gandi in the SE and Ambakapallein the NW. Presently, two different types of uranium mineralization are characterized on the basis of field observations, mapping and structural interpretation, petro-mineralogy and geochemistry. Although the host rock is same for both types, the mechanism of uranium enrichment is totally different. The Ambakapalle uranium mineralization is controlled by fault zone and associated hydrothermal activity. Whereas, the Tummalapalle uranium mineralization is litho-controlled in nature influenced by suitable four ‘P’ factors, i.e., provenance, porositypermeability, precipitation and preservation. The geochemical characterization of Gulcheru quartzite suggest a passive margin type of provenance setting. Petro-mineralogically the quartz arenite suggests enough textural as well as mineralogical maturity. Ambakapalle quartzite is slightly strained and deformed due to faulting. Analysis of selected samples recorded 0.01% to 0.048% U3O8 and <0.01% ThO2. Petrographic observation revealed that the anomalies were appeared due to secondary uranium minerals occurring as surficial encrustations, fracture filling and lesser irregular patches. Structural analysis suggests the mineralization along E-W trace slip fault is possibly consistent in sub-surface. Tummalapalle quartzite is relatively less deformed arenitic in nature with significant enrichment in MREE. The genetic models for the two types of mineralization is totally different.
文摘In this work,the effects of the methane gas flow and the internal oscillating electric field between electrodes on radio-frequency(RF)atmospheric pressure argon/methane plasma jet and process of diamond-like carbon(DLC)film deposition have been investigated.Properties of RF atmospheric Ar/methane plasma jet such as active species density,length,electron temperature,appearance and ionization process of argon/methane plasma jet are changed due to the changing of methane flow content and electric field vector and its gradient.With increasing methane flow,the formation of C2 hydrocarbon and CH band content is decreased because injected electrical energy to a mixture of Ar/methane gases is insufficient to stabilize the ionization process of methane gas and the electrical-chemical reaction rate is decreased.With shortening the gas gap between two electrodes,electric field strength and its gradient are increased leading to more energy injection to the electron.Electrical-chemical reactions are strengthened leading to increasing the CH band content.These phenomena introduce the Ar/methane plasma jet in different modes causing to deposit the DLC film with different structures and properties.With using quartz glass and alumina ceramic as dielectric barriers tubes,RF atmospheric pressure Ar/methane plasma jet has been used to deposit DLC coating in different modes.Increasing methane content and shortening the gas gap leads to decreasing sp3 bonded content and the quality of the deposited film.
文摘We theoretically analyze the transient properties of a probe field absorption and dispersion in a coupled semiconductor double-quantum-dot nanostructure.We show that in the presence of the Gaussian laser beams,absorption and dispersion of the probe field can be dramatically influenced by the relative phase between applied fields and intensity of the Gaussian laser beams.Transient and steady-state behaviors of the probe field absorption and dispersion are discussed to estimate the required switching time.The estimated range is between 5-8 ps for subluminal to superluminal light propagation.
文摘Plate tectonic activity has played a critical role in the development of petrotectonic associations in the Kadiri schist belt. The calc alkaline association of basalt, andesite, dacite and rhyolite (BADR) is the signature volcanic rock suite of the convergent margin. The N-S belt has gone below the unconformity plane of Cuddapah sediments. In the northern part geochemical and structural attributes of the Kadiri greenstone belt is studied along with microscopic observations of selected samples. Harker diagram plots of major elements generally indicate a liquid line of descent from a common source, such that BADR rocks are derived from a common parent magma of basaltic to andesitic composition. These calc-alkaline volcanic rocks are formed at convergent margins where more silicic rocks represent more highly fractionated melt. All the litho-units of this greenstone belt indicate crush and strain effects. The stretched pebbles in the deformed volcanic matrix with tectonite development along with associated greenschist facies metamorphism, alteration and hydration is remarkable. Flow foliation plane with N-S strike and very low angle (5~ to 10~) easterly dip and N-S axial planar schistosity formed due to later phase isoclinal folding can be clearly identified in the field. Basic intrusives are quite common in the surrounding area. All the observations including the field setting and geochemistry clearly demonstrate ocean-continent subduction as the tectonic environment of the study area.
文摘In fast reactors, the inherent neutron source strength is often insufficient for monitoring the reactor start-up operation with ex-core detectors. To increase the subcritical neutron flux, an auxiliary neutron source subassembly(SSA) is generally used to overcome this problem. In this study, the estimated neutron source strength and detector count rate of an antimony-beryllium-based SSA are obtained using the deterministic transport code DORT and Monte Carlo calculations. Because the antimony activation rate is a critical parameter, its sensitivity to the capture cross section and neutron flux spectrum is studied. The reaction cross section sensitivity is studied by considering data from different evaluated nuclear data files.It is observed that, because of the variation in the cross sections from different evaluated nuclear data files, the values of the saturation gamma(> 1.67 MeV) activity and neutron strength predicted by ORIGEN2 lie within ±2%.The obtained antimony activation rate and sensitivity to the neutron flux are partially validated by irradiating samples of antimony in the KAMINI reactor. The average onegroup capture cross sections of bare and cadmium-covered 123Sb samples obtained by the ratio method are 4.0 and 1.78 b, respectively. The results of the calculation predicting the activated neutron source strength as a function of operating time and sensitivity to the neutron spectrum in the irradiation region are also presented.
文摘The current sheath velocity in 0.25 Torr gas pressure of Filippov type plasma focus is studied experimentally. By using two tridimensional magnetic probes on top of the anode surface, the current sheath velocity is measured for argon, oxygen and nitrogen. Additionally, the effect of charging voltage on the current sheath velocity is studied in both axial and radial phases. We found that, the maximum current sheath velocities at both radial and axial phases are respectively 4.33 ± 0.28 (cm/μs) and 3.92 ± 0.75 (cm/μs) with argon as the working gas at 17 kV. Also, the minimum values of current sheath velocity are 1.48 ± 0.15 (cm/μs) at the radial phase and 1.14 ± 0.09 (cm/μs) at the axial phase with oxygen at 12 kV. The current sheath velocity at the radial phase is higher than that at the axial phase for all gases and voltages. In this study, variation of the full width half maximum (FWHM) of magnetic probe signals with voltage is investigated for different gases at radial and axial phases.
文摘Iron irrespective of its valency states forms bluish 1:1 cationic, bluish-violet 1:3 neutral and purple 1:3 anionic complexes with 2,3-dihydroxynaphthalene, at pH 2 - 3, 4 - 5 and 8 - 10, respectively. The cationic bluish complex is highly insensitive and not extractable in organic solvents. Similarly, the bluish violet 1:3 neutral complex is of moderate sensitivity, and it is extractable in organic solvents with reduced sensitivity. The purple 1:3 anionic complex is as such not extractable in any organic solvents. However, in the surfactant medium of the cationic surfactant, cetyltrimethylammonium bromide it is extractable in organic solvents with enhanced sensitivity. The 1:3 anionic complex which is extractable in organic solvents as an ion associate in the presence of cetyltrimethyl ammonium bromide is chosen for application to Silicate rocks, Minerals, Soils, Stream sediments, Concentrates, Tobacco leaves, Cigarettes and Waters, for accurate and sensitive determination of iron owing to facile extraction of iron, enhanced sensitivity high selectivity and better reproducibility of results. The present paper describes a systematic study on the development of an extraction spectrophotometric method for the determination of iron in samples of diverse matrices.
文摘Amplifying the attosecond pulse by the chirp pulse amplification method is impossible. Furthermore, the intensity of attosecond pulse is low in the interaction of laser pulse and underdense plasma. This motivates us to propose using a multi-color pulse to produce the high intense attosecond pulse. In the present study, the relativistic interaction of a three-color linearly-polarized laser-pulse with highly overdense plasma is studied. We show that the combination of ω1, ω2 and ω3 frequencies decreases the instance full width at half maximum reflected attosecond pulse train from the overdense plasma surface. Moreover, we show that the three-color pulse increases the intensity of generated harmonics, which is explained by the relativistic oscillating mirror model. The obtained results demonstrate that if the three-color laser pulse interacts with overdense plasma, it will enhance two orders of magnitude of intensity of ultra short attosecond pulses in comparison with monochromatic pulse.
文摘In this work, the effect of electrical discharge on nitrate concentration is considered in aqueous solution. The atmospheric pressure plasma was produced by a high-voltage power supply at 27 k Hz using pin-to-pin configuration. Air, argon,and argon/methane mixture were used to study the working gas effect. UV-VIS spectroscopy and ion chromatography were used to analyze the effect of the electrical discharge on nitrate concentration in deionized water. Optical emission spectroscopy(OES) was applied to diagnose active species inside and on the surface of the deionized water solution. The results of the present work showed that the atmospheric pressure electric discharge with air increases nitrate concentration while it remains constant using argon and argon/methane electrical discharges. It was also revealed that in the presence of air, the electrical discharge reduces p H, acidifying the solution and increasing solution conductivity due to production of extra nitrate ions. On the other hand, argon electrical discharge increases p H and conductivity due to production of OHion in water.
文摘Realizing media independence in today’s communication system remains an open problem by and large.Information retrieval,mostly through the Internet,is becoming the most demanding feature in technological progress and this web-based data access should ideally be in user-selective form.While blind-folded access of data through the World Wide Web is quite streamlined,the counter-half of the facet,namely,seamless access of information database pertaining to a specific end-device,e.g.robotic systems,is still in a formative stage.This paradigm of access as well as systematic query-based retrieval of data,related to the physical enddevice is very crucial in designing the Internet-based network control of the same in real-time.Moreover,this control of the end-device is directly linked up to the characteristics of three coupled metrics,namely,‘multiple databases’,‘multiple servers’and‘multiple inputs’(to each server).This triad,viz.database-input-server(DIS)plays a significant role in overall performance of the system,the background details of which is still very sketchy in global research community.This work addresses the technical issues associated with this theology,with specific reference to formalism of a customized DIS considering real-time delay analysis.The present paper delineates the developmental paradigms of novel multi-input multioutput communication semantics for retrieving web-based information from physical devices,namely,two representative robotic sub-systems in a coherent and homogeneous mode.The developed protocol can be entrusted for use in real-time in a complete user-friendly manner.
文摘Ozone plays a significant part in regulating climate change and the chemical characteristics of the atmosphere. Changes in atmospheric ozone can be studied in more detail using ground-based and satellite-based instruments. Studies on the long-term global changes in total column ozone have begun more than three-decade ago using satellite data. The main objective of this work is to analyze the Total Column Ozone (TCO) variations, and tropo-spheric ozone variations over different twenty locations in the Indian sub-continent by using Total Ozone Mapping Spectrometer (TOMS) and AURA OMI/MLS data. The long-term analysis of total column ozone is divided into two phases (1979-1994 and 2005-2018), and tropospheric ozone for one phase (2005-2018) in order to detect changes in the ozone trend pattern. The results of linear regression analysis show a declining trend of total column ozone, and an increasing trend of tropospheric ozone over the selected locations. The impact of wind pattern on the variation of ozone has been analyzed by using NCEP reanalysis data, and found that wind patterns played a prominent role in spatial and temporal changes in total and tropospheric ozone distribution over the subcontinent. Latitudinal variation of total column ozone from Nagarcoil to Anantanag has also been studied for the years 1979, 1994, 2005, and 2018, which indicates an increase in ozone concentration with latitude.
文摘Seaweed is an enormous resource comprised with natural bioactive compounds with several therapeutic effects including anticancer activity.In this context,the biochemical composition of seaweed plays a major role.Many biochemical compounds isolated from seaweed,fractions of seaweed and crude extracts has revealed ability of seaweed to fight against several cancer types.In this contrast seaweed extracts inhibit cancer cell growth and proliferation by inducing apoptosis and by inhibiting metastasis activity.In this review,biochemical and anticancer properties of seaweeds are discussed and this will provide the basic information to develop a novel chemotherapeutic drug to challenge the cancers.
文摘Cilia and flagella are organelles of motility that enable cells to swim or move liquid over its surface. An exhaustive literature survey for the presence of the organelle in organisms across phyla showed that most animal cells harbor cilia in contrast to very few fungal cells. While this was not unexpected, it was the position and arrangement of this organelle in each cell that intrigued our attention. Natural selection might have favored motility over chemotaxis;and it would have done so to evolve a stable structure that could have undergone an optimization process requiring a precise geometry in the shape of cells and the structure that would help cells to move. The positioning of such a structure would play a pre-dominant role in optimal motility. It is now known that the flagellar position of a cell is a genetically distinct trait, occasionally used in phylogeny of bacteria, distributed in distinguishing patterns over cellular surface, but basically are of two types, either polar (one flagellum arising from one pole per cell) or peritrichous (lateral flagella distributed over the entire cell surface). Irrespective of the cellular habitat, flagella origin, ultrastructure and proteome, the present investigation surveyed 26 sub-types of flagellar arrangements from as many species as possible. A peculiar pattern ensued-Prokaryotes harbored predominantly polar and peritrichous types;eukaryotes showed a mere change of the peritrichous one. These numbers when used to create a Similarity tree depicted a similarity distance of 14 between the Eubacteria and Archaebacteria forming the first neighborhood;Protozoans, Algae, Fungi, Plantae and Animalia formed a second neighborhood. We offer a working hypothesis for this pattern and the gradual shift in the flagellar arrangement from polar, peritrichous, sub-apical, and apical to lateral throughout evolution.
基金Support from the Swedish Government Strategic Research Areas in Materials Science on Functional Materials at Linköping University(Faculty Grant SFO-Mat-LiU No.2009-00971)Knut&Alice Wallenberg Foundation New States of Matter 2014-2019(COTXS)is gratefully acknowledged.Analysis of first-principles calculations of defect properties was supported by the Ministry of Education and Science of the Russian Federation(Grant no.14.Y26.31.0005).Applications of the model Hamiltonians were supported by the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST“MISIS”(No.K2-2017-080)implemented by a governmental decree dated 16 March 2013,no.211.A.G.acknowledges the support from the National Research Development and Innovation Office of Hungary(NKFIH)within the Quantum Technology National Excellence Program(Project no.2017-1.2.1-NKP-2017-00001)the EU QuantERA projects QMagine and Nanospin(NKFIH Grant Nos.127889 and 127902,respectively),and the EU H2020 ASTERIQS project.
文摘Point defect research in semiconductors has gained remarkable new momentum due to the identification of special point defects that can implement qubits and single photon emitters with unique characteristics.Indeed,these implementations are among the few alternatives for quantum technologies that may operate even at room temperature,and therefore discoveries and characterization of novel point defects may highly facilitate future solid state quantum technologies.First principles calculations play an important role in point defect research,since they provide a direct,extended insight into the formation of the defect states.In the last decades,considerable efforts have been made to calculate spin-dependent properties of point defects from first principles.The developed methods have already demonstrated their essential role in quantitative understanding of the physics and application of point defect qubits.Here,we review and discuss accuracy aspects of these novel ab initio methods and report on their most relevant applications for existing point defect qubits in semiconductors.We pay attention to the advantages and limitations of the methodological solutions and highlight additional developments that are expected in the near future.Moreover,we discuss the opportunity of a systematic search for potential point defect qubits,as well as the possible development of predictive spin dynamic simulations facilitated by ab initio calculations of spin-dependent quantities.
基金This work was financially supported by the Knut and Alice Wallenberg Foundation through WBSQD2 project(Grant No.2018.0071)G.B.is supported by NKFIH PD-17-125261+4 种基金“Bolyai”Research Scholarship of HAS.Ö.L.acknowledges grant NKFIH K120569the support of the Alexander von Humboldt FoundationA.G.acknowledges the Hungarian NKFIH grants No.KKP129866 of the National Excellence Program of Quantum-coherent materials projectÖ.L.and A.G.acknowledge support of the NKFIH through the National Quantum Technology Program(Grant No.2017-1.2.1-NKP-2017-00001)The calculations were performed on resources provided by the Swedish National Infrastructure for Computing(SNIC 2018/3-625 and SNIC 2019/1-11)at the National Supercomputer Center(NSC)and by the Wigner RCP.
文摘Highly correlated orbitals coupled with phonons in two-dimension are identified for paramagnetic and optically active boron vacancy in hexagonal boron nitride by first principles methods which are responsible for recently observed optically detected magnetic resonance signal.Here,we report ab initio analysis of the correlated electronic structure of this center by density matrix renormalization group and Kohn-Sham density functional theory methods.By establishing the nature of the bright and dark states as well as the position of the energy levels,we provide a complete description of the magneto-optical properties and corresponding radiative and non-radiative routes which are responsible for the optical spin polarization and spin dependent luminescence of the defect.Our findings pave the way toward advancing the identification and characterization of room temperature quantum bits in two-dimensional solids.
文摘An idea of the surface plasmon resonance(SPR)has been utilized for the design of highly sensitive sensors based on the wagon-wheel fiber technology.Such sensors are sensitive to changes in the refractive index of sample analyte.In this study,a three-strut wagon-wheel structure,coated with the gold layer of nano-sized thickness,has been proposed as the SPR sensor.Finite element method is employed to simulate and tune the proposed SPR's design,which leads to a highly sensitive and multichannel plasmonic sensor with the ability for a dual reading on a single analyte or simultaneous identification of two analytes.In this design,suitable thickness values for the gold layer and core struts are determined.Sensitivities of the detector due to the first resonance peak, second resonance peak,and the difference in resonance peaks are calculated to be 1120nm/RIU, 1540nm/RIU,and 420nm/RIU,respectively,when analytes are placed in all three channels of the fiber.Sensitivity of the detector with respect to the second resonant peak for analyte in Channels 2 and 3 is also found to be 1252nm/RIU when Channel 1 is filled with the reference.The sensitivity and resolution of the sensor increase as the refractive index of the analyte increases by almost a linear proportion.If the sensor is utilized to detect the difference in two peaks,it would substantially reduce the noise,and the best result is expected.The thicknesses of the struts and the gold layer are proper parameters to be tuned in designing the detector.
基金supported by the National Key Research and Development Program of China(2016YFA0301901)the National Natural Science Foundation of China(11374178 and 11574002)+3 种基金the National Research Foundation of Singapore(NRF Award No.NRF-NRFF2016-02 and project NRF2017-NRFANR004 Van Qu Te)the Competitive Research Programme(CRP Award No.NRF-CRP14-2014-02)the Ministry of Education in Singapore Tier 1 RG190/17the Oxford Martin School
文摘The NOT gate that flips a classical bit is ubiquitous in classical information processing.However its quantum analogue,the universal NOT(UNOT) gate that flips a quantum spin in any alignment into its antipodal counterpart is strictly forbidden.Here we explore the connection between this discrepancy and how UNOT gates affect classical and quantum correlations.We show that while a UNOT gate always preserves classical correlations between two spins,it can non-locally increase or decrease their shared discord in ways that allow violation of the data processing inequality.We experimentally illustrate this using a multi-level trapped ^(171)Yb^+ ion that allows simulation of anti-unitary operations.
基金Helmholtz International Center for FAIR(HIC for FAIR)Helmholtz Association(IK-RU-002)+5 种基金Russian Ministry of Education and Science(NSh-932.2014.2)Russian Foundation for Basic Research(14-02-00090-a)Polish National Science Center(UMO-2011/01/B/ST2/01943)Polish Ministry of Science and Higher Education(0079/DIA/2014/43,Grant Diamentowy)Helmholtz-CAS Joint Research Group(HCJRG-108)FPA2009-08848 contract(MICINN,Spain)
文摘An experiment aimed to investigate the two-proton(2p) decay of the previously unknown nucleus ^(30)Ar was performed at GSI. By tracking the decay products in-flight with silicon micro-strip detectors, the 2p decays of ^(30)Ar were observed for the first time. For the calibration purpose, 2p decays of ^(19)Mg were also remeasured by tracking the coincident ^(17)Ne+p+p trajectories. By comparing the measured angular p-17 Ne correlations with those obtained from the corresponding Monte Carlo simulations,the simultaneous 2p decay of ^(19)Mg ground state and the sequential 2p emission of several known excited states of ^(19)Mg were confirmed. One new excited state in ^(19)Mg and two new excited states in ^(18)Na were observed.