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A multiwavelength view of a classical T Tauri star CV Cha

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Research in Astronomy and Astrophysics 2019年第1期19卷 75-86页

作者： Jeewan Chandra pandey Subhajeet Karmakar Arti Joshi Saurabh Sharma Shashi Bhushan pandey Anil kumar pandey Aryabhatta Research Institute of Observational Sciences (ARIES)

Using long-term optical, ultraviolet(UV) and X-ray data, we present a study of a classical T Tauri star CV Cha. The V-band light curve obtained from the All Sky Automated Survey(ASAS) shows short as well as long-term variability. The short-term variability could be due to rotational modulation of CV Cha. We derive the rotational period of 3.714 ± 0.001 d for CV Cha. UV light curves obtained from Swift also show the variations. X-ray light curves from XMM-Newton and Swift do not show any significant short as well as long-term variability. However, the light curve from Chandra appears to be variable, which could be due to the emergence of flaring activities. X-ray spectra from all observations are explained well by the single temperature plasma of 0.95 keV with X-ray luminosity of 1030.4erg s-1in the 0.5–7.5 keV energy band. It appears that variability in optical and UV bands could be due to the presence of both hot and cool spots on the surface, while X-ray emission is dominated by magnetic processes.

关键词： stars:activity stars:individual(CV Cha) stars:pre-main sequence stars:variable:T Tauri X-ray:stars

Interbasinal marker intervals——A case study from the Jurassic basins of Kachchh and Jaisalmer, western India

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Science China Earth Sciences 2009年第12期52卷 1924-1931页

作者： pandey Dhirendra kumar FüRSICH Franz Theodor Department of Geology University of Rajasthan Jaipur 302004 India Institut für Geologie und Palontologie der Universitt Würzburg Pleicherwall 1 D-97070 Würzburg Germany GeoZentrum Nordbayern der Universitt Erlangen Loewenichstr. 28 D-91054 Erlangen Germany

The Kachchh Basin and the Jaisalmer Basin are two neighboring Mesozoic sedimentary basins at the western margin of the Indian craton. The Jurassic succession of the Kachchh Basin is more complete and more fossiliferous than that of the Jaisalmer Basin. Consequently, intrabasinal correlation of the sedimentary units has been possible in the Kachchh Basin, but not in the Jaisalmer Basin. However, some marker beds existing in the Kachchh Basin can be recognized also in the Jaisalmer Basin. Ammonite evidence shows that they are time-equivalent. The following four units form marker intervals in both basins: (1) the pebbly rudstone unit with Isastrea bernardiana and Leptosphinctes of the Kaladongar Formation (Kachchh Basin) and the Isastrea bernardiana-bearing rudstone of the Jaisalmer Formation (Jaisalmer Basin) both represent transgressive systems tract deposits dated as Late Bajocian; (2) bioturbated micrites with anomalodesmatan bivalves within the Goradongar Yellow Flagstone Member (Kachchh Basin) and bioturbated units in the Fort Member (Jaisalmer Basin) represent maximum flooding zone deposits of the Middle to Late Bathonian; (3) trough-crossbedded, sandy packto grainstones of the Raimalro Limestone Member (Kachchh Basin) and the basal limestone-sandstone unit of the Kuldhar section of the Jaisalmer Formation (Jaisalmer Basin) correspond to Late Bathonain transgressive systems tract deposits; and (4) ferruginous ooid-bearing carbonates with hardgrounds of the Dhosa Oolite member (Kachchh Basin) and the middle part of the Jajiya Member (Jaisalmer Basin) are Oxfordian transgressive systems tract deposits. The fact that in both basins similar biofacies prevailed during certain time intervals demonstrates a common control of their depositional history. As the two basins represent different tectonic settings, the most likely controlling factors were the relative sea-level changes produced by eustatic processes, a common subsidence history of the northwestern margin of t

关键词： Jurassic interbasinal correlation marker beds sequence stratigraphy India

A comprehensive review of rectangular duct solar air heaters featuring artificial roughness

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Clean Energy 2024年第5期8卷 186-217页

作者： Ravi Shankar Rajeev kumar Arun kumar pandey Deep Singh Thakur Department of Mechanical Engineering Rajkiya Engineering College BandaUttar Pradesh 210201India Department of Mechanical Engineering Institute of Engineering&TechnologyLucknowUttar Pradesh 226021India Department of Mechanical Engineering Bundelkhand Institute of Engineering&TechnologyJhansiUttar Pradesh 284128India

Solar air heaters(SAHs)are widely used solar thermal systems with applications in diverse ***,its effectiveness is re-strained by low convective heat transfer(HT)coefficients at the absorber plate,leading to inefficient HT,and the elevated temperature of the absorber plate causes significant heat losses,reducing thermal *** study addresses these challenges by introducing ribs or roughness on the absorber plate creating turbulence in the airflow,resulting in significant *** research inves-tigates various rib configurations,the influence of rib parameters,performance methods,and arrangements to evaluate their HT and friction *** these rib configurations,a comparative analysis is done on various factors such as the Nusselt number ratio,thermal enhancement factor,friction factor ratio,and thermal efficiency to optimize distinct roughness parameters and rib ar-rangement *** study also provides valuable recommendations from existing literature,offering insights into the effective design,prospects,and implementation of SAH systems.

关键词： solar air heater artificial roughness low heat transfer heating solar energy

Evaluation of thermostable endoglucanase in Paenibacillus lautus strain BHU3 for yield enhancement

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Systems Microbiology and Biomanufacturing 2022年第4期2卷 607-622页

作者： Suman Yadav Anand kumar pandey Suresh kumar Dubey Molecular Ecology Laboratory Centre of Advanced Study in BotanyInstitute of ScienceBanaras Hindu UniversityVaranasi 221005India Department of Biotechnology Engineering Institute of Engineering and TechnologyBundelkhand UniversityJhansi 284128India

In the present study,Paenibacillus lautus strain BHU3 isolated from landfill soil was evaluated for the presence of potential endoglucanases which are the first candidate of cellulase enzyme system to act on ***-silico analysis revealed high potential thermostable endoglucanases which can efficiently interact with *** most potent and thermostable endoglucanase(locus tag ***30_18280)belonged to glycosyl family-5 and had interaction energy of−12.981 kcal/mol for the best docked cluster containing three out of ten docking conformations,and Tm value of 73.3℃.MD simulation of 100 ns proved highly stable binding interactions of CPZ30_18280 endoglucanase with cellulose with root mean square deviation(RMSD)values ranging from 0.15 to 0.30 *** interactions with characteristic active site residues(tyrosine,tryptophan and aspartate)of glycosyl family-5 endoglucanases were ***,to enhance the production of endoglucanases,the fermentation conditions were optimized employing approaches like one factor at a time(OFAT)and response surface methodology(RSM).Maximum activity of endoglucanase was determined at 60℃.The optimized condi-tions for enhanced production of endoglucanase(10.15 U/mL)were pH 6.63,yeast extract conc.3.44 g/L,wheat bran 3.59%,and inoculum size 2.65%.Hence,*** strain BHU3 has enormous potential to synthesize highly efficient thermostable endoglucanases under optimized regime using ***,it could find immense industrial applications including large scale cellulose conversion to bioethanol.

关键词： Agrowastes Cellulose RAST Endoglucanase Paenibacillus lautus

One Step Synthesis and Growth Mechanism of Carbon Nanotubes

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Journal of Materials Science & Technology 2014年第2期30卷 112-116页

作者： Akshay kumar K.Singh O.P.pandey Sri Guru Granth Sahib World University School of Physics and Materials Science Thapar University

A simple one step, reproducible, synthesis route for carbon nanotubes was proposed. No external catalyst was used for the synthesis. These nanotubes were obtained after decomposition of acetone at 650 ℃ in a specially designed autoclave. The pressure generated due to decomposition of acetone played a vital role in the synthesis. The X-ray diffraction pattern and transmission electron microscopy of the sample showed that the diameter of nanotubes is in the range of 3-14 nm. The thermo gravimetric analysis showed 3% weight loss below 500 ℃; the content of amorphous carbon is very less. The growth mechanism of CNTs was also proposed in the present paper.

关键词： Nanostructures Chemical synthesis Electron diffraction Raman spectroscopy Defects

Low power digitally controlled oscillator designs with a novel 3-transistor XNOR gate

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Journal of Semiconductors 2012年第3期33卷 52-59页

作者： Manoj kumar Sandeep K.Arya Sujata pandey Department of Electronics&Communication Engineering Guru Jambheshwar University of Science&Technology amity University

Digital controlled oscillators（DCOs） are the core of all digital phase locked loop（ADPLL） circuits. Here,DCO structures with reduced hardware and power consumption having full digital control have been proposed. Three different DCO architectures have been proposed based on ring based ***,four and five bit controlled DCO with NMOS,PMOS and NMOS PMOS transistor switching networks are presented.A three-transistor XNOR gate has been used as the inverter which is used as the delay *** has been controlled digitally with a switch network of NMOS and PMOS *** three bit DCO with one NMOS network shows frequency variations of 1.6141-1.8790 GHz with power consumption variations 251.9224-276.8591μW. The four bit DCO with one NMOS network shows frequency variation of 1.6229-1.8868 GHz with varying power consumption of 251.9225-278.0740μW.A six bit DCO with one NMOS switching network gave an output frequency of 1.7237-1.8962 GHz with power consumption of 251.928-278.998μ*** frequency and power consumption results for 4 6 bit DCO circuits with one PMOS and NMOS PMOS switching network have also been *** phase noise parameter with an offset frequency of 1 MHz has also been reported for the proposed *** with earlier reported circuits have been made and the present approach shows advantages over previous circuits.

关键词： digital control oscillator delay cell power consumption voltage controlled oscillators

Glacier-Glacial Lake Interactions and Glacial Lake Development in the Central Himalaya,India(1994–2017)

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Journal of Earth Science 2021年第6期32卷 1563-1574页

作者： Pratima pandey Sheikh Nawaz Ali Prashant kumar Champati Ray Indian Institute of Remote Sensing DehradunIndia Birbal Sahni Institute of Palaeosciences LucknowIndia

Despite several regional glacier and glacier lake inventories, the relationship between receding glacier, glacial lake evolution(glacial-lake interactions) and their sensitivity to different forcing factors have not been properly understood yet. To better understand these processes, we used satellite images collected in 1994, 2015 and 2017 to monitor the spatially-explicit evolution of glacial lakes and glacier changes. The results show a total of 1 353 glacial lakes covering an area of 7.96 km;in the year 2015. Out of these, a total of 137 glacial lakes having an area of >0.01 km;and located within 2 km periphery of mother glacier have been selected for the monitoring of spatial development between 1994 and 2017. We found an increase in the total lake area from ~4.9 to ~7.73 km;between 1994 and 2017,corresponding to an overall expansion of ~57%. The total area covered by the glaciers associated with these lakes reduced from ~365 km;in 1994 to ~358 km^(2) in 2017, accounting for a glacier loss of ~7 km^(2) and corresponding to ~1.92% reduction. Our study results are in agreement with global glacier behavior, revealing a rapid glacier recession and accelerated glacial lake expansion under an unprecedented climate change scenario. In addition, the results suggest a significant reduction in the glacier area and a close relationship between the glacier melting and lake changes.

关键词： glacial lake expansion glacier change glacier-lake interaction Central Himalaya climate

Applications of artificial intelligence in power system operation, control and planning: a review

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Clean Energy 2023年第6期7卷 1199-1218页

作者： Utkarsh pandey Anshumaan Pathak Adesh kumar Surajit Mondal Department of Electrical and Electronics Engineering School of Advanced EngineeringUniversity of Petroleum and Energy StudiesDehradun248007India

As different artificial intelligence(AI)techniques continue to evolve,power systems are undergoing significant technological changes with the primary goal of reducing computational time,decreasing utility and consumer costs and ensuring the reliable operation of an electrical power *** techniques compute large amounts of data at a faster speed than numerical optimization methods with higher processing *** these features,AI techniques can further automate and increase the performance of power *** paper presents a comprehensive overview of diverse AI techniques that can be applied in power system operation,control and planning,aiming to facilitate their various *** explained how AI can be used to resolve system frequency changes,maintain the voltage profile to minimize transmission losses,reduce the fault rate and minimize reactive current in distributed sys-tems to increase the power factor and improve the voltage profile.

关键词： artificial neural network genetic algorithm fuzzy logic adaptive neuro-fuzzy interference system artificial bee colony optimization ant colony optimization particle swarm optimization

A boosted negative bit-line SRAM with write-assisted cell in 45 nm CMOS technology

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Journal of Semiconductors 2018年第2期39卷 51-62页

作者： Vipul Bhatnagar Pradeep kumar Neeta pandey Sujata pandey Department of Electronics and Communication Engineering Amity University Uttar Pradesh Department of Electronics and Communication Engineering Delhi Technological University

A new 11 T SRAM cell with write-assist is proposed to improve operation at low supply voltage. In this technique, a negative bit-line voltage is applied to one of the write bit-lines, while a boosted voltage is applied to the other write bit-line where transmission gate access is used in proposed 11 T cell. Supply voltage to one of the inverters is interrupted to weaken the feedback. Improved write feature is attributed to strengthened write access devices and weakened feedback loop of cell at the same time. Amount of boosting required for write performance improvement is also reduced due to feedback weakening, solving the persistent problem of half-selected cells and reliability reduction of access devices with the other suggested boosted and negative bit-line techniques. The proposed design improves write time by 79%, 63% and slower by 52% with respect to LP 10 T, WRE 8 T and 6 T cells respectively. It is found that write margin for the proposed cell is improved by about 4×, 2.4× and 5.37× compared to WRE8 T, LP10 T and 6 T respectively. The proposed cell with boosted negative bit line（BNBL） provides47%, 31%, and 68.4% improvement in write margin with respect to no write-assist, negative bit line（NBL） and boosted bit line（BBL） write-assist respectively. Also, new sensing circuit with replica bit-line is proposed to give a more precise timing of applying boosted voltages for improved results. All simulations are done on TSMC 45 nm CMOS technology.

关键词： write-assist in SRAM boosted negative bit-line reduced write delay low leakage reduced supply voltage