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Why is graphene an extraordinary material? A review based on a decade of research

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Frontiers of Materials Science 2022年第2期16卷 1-39页

作者： Sachin Sharma Ashok kumar Shahid BASHIR Kasi ramesh Subramaniam ramesh Centre for Ionics University of Malaya Department of PhysicsFaculty of ScienceUniversiti MalayaKuala Lumpur 50603Malaysia Higher Institution Centre of Excellence(HICoE) UM Power Energy Dedicated Advanced Centre(UMPEDAC)Level 4Wisma R&DUniversiti MalayaJalan Pantai BaharuKuala Lumpur 59990Malaysia

During this decade,graphene which is a thin layer of carbon material along at ease with synthesis and functionalization has become a hot topic of research owing to excellent mechanical strength,very good current density,high thermal conductivity,superior electrical conductivity,large surface area,and good electron *** research on graphene has exponentially accelerated specially when Geim and Novoselov developed and analyzed *** this basis,for industrial application,researchers are exploring different techniques to produce high-quality ***,reviewed in this article is a brief introduction to graphene and its derivatives along with some of the methods developed to synthesize graphene and its prospective applications in both research and *** this work,recent advances on applications of graphene in various fields such as sensors,energy storage,energy harvesting,high-speed optoelectronics,supercapacitors,touch-based flexible screens,and organic light emitting diode displays have been summarized.

关键词： graphene graphene oxide electrochemical sensor fuel cell supercapacitor dye-sensitized fuel cell lithium battery energy storage

Evaluation of Rainfall Tendency for the Twentieth Century over Indira Sagar Region in Central India

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American Journal of Climate Change 2024年第1期13卷 47-68页

作者： Rituraj Shukla Deepak Khare ramesh P. Rudra Priti Tiwari Himanshu Sharma Prasad Daggupati Pradeep Goel School of Engineering University of Guelph Guelph Canada Department of Water Resources Development and Management Indian Institute of Technology Roorkee India Indira Gandhi Agricultural University Raipur India Department of Civil Engineering Institute of Infrastructure Technology Research and Management (IITRAM) Ahmedabad India

The study investigates long-term changes in annual and seasonal rainfall patterns in the Indira Sagar Region of Madhya Pradesh, India, from 1901 to 2010. Agriculture sustainability, food supply, natural resource development, and hydropower system reliability in the region rely heavily on monsoon rainfall. Monthly rainfall data from three stations (East Nimar, Barwani, and West Nimar) were analyzed. Initially, the pre-whitening method was applied to eliminate serial correlation effects from the rainfall data series. Subsequently, statistical trends in annual and seasonal rainfall were assessed using both parametric (student-t test) and non-parametric tests [Mann-Kendall, Sen’s slope estimator, and Cumulative Sum (CUSUM)]. The magnitude of the rainfall trend was determined using Theil-Sen’s slope estimator. Spatial analysis of the Mann-Kendall test on an annual basis revealed a statistically insignificant decreasing trend for Barwani and East Nimar and an increasing trend for West Nimar. On a seasonal basis, the monsoon season contributes a significant percentage (88.33%) to the total annual rainfall. The CUSUM test results indicated a shift change detection in annual rainfall data for Barwani in 1997, while shifts were observed in West and East Nimar stations in 1929. These findings offer valuable insights into regional rainfall behavior, aiding in the planning and management of water resources and ecological systems.

关键词： Precipitation Parametric Non-Parametric Tests Trend Analysis Serial Correlations

Pharmacological adjuvants for diabetic vitrectomy surgery

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World Journal of Methodology 2024年第4期14卷 84-90页

作者： ramesh Venkatesh Chaitra Jayadev Vishma Prabhu Priyanka Gandhi Rupal Kathare Naresh K Yadav Ayushi Choudhary Jay Chhablani Department of Ophthalmology Narayana NethralayaBangalore 560010India Department of Retina Narayana Nethralaya Eye InstituteBangalore 560010India Department of Vitreo Retina Narayana NethralayaRetina ServSuper Specialty Eye Hospital and Post Graduate Institute of OphthalmologyBangalore 560010India Department of Retina University of Pittsburg School of MedicinePittsburgPA 15213United States

Diabetic vitrectomy is a highly intricate surgical procedure performed during the advanced stages of diabetic retinopathy(DR).It is used to treat conditions such as tractional or combined retinal detachment,vitreous hemorrhage,and subhyaloid hemorrhage,which are all severe manifestations of proliferative *** results of the surgery are uncertain and *** surgery has made significant progress since the early stages of *** the past ten years,advancements in intravitreal pharmacotherapy have emerged,offering new possibilities to improve the surgical results for our *** the realm of medical terminology,an"adjunct"refers to a pharmaceutical or substance employed to aid or expedite the primary therapeutic intervention for a particular *** introduction has broadened the range of therapeutic choices that are accessible prior to,during,and following surgical *** review article will specifically analyze the pharmacological adjuncts used in diabetic vitrectomy surgery,with a focus on their role in facilitating or aiding specific steps of the *** implementation of this system of categorization offers benefits to the surgeon by allowing them to foresee potential difficulties that may occur during the surgical procedure and to choose the appropriate pharmacological agent to effectively tackle these challenges,thus enhancing surgical success rates.

关键词： Diabetic retinopathy Vitrectomy Intravitreal injections Anti-vascular endothelial growth factor Adjuvants Outcomes

In-Situ Hydrothermal Synthesis of Bi–Bi2O2CO3 Heterojunction Photocatalyst with Enhanced Visible Light Photocatalytic Activity

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Nano-Micro Letters 2017年第2期9卷 58-67页

作者： Prasenjit Kar Tuhin kumar Maji ramesh Nandi Peter Lemmens Samir kumar Pal Department of Chemical Biological and Macromolecular Sciences S.N.Bose National Centre for Basic SciencesBlock JDSector ⅢSaltLakeKolkata 700106India Institute for Condensed Matter Physics TU BraunschweigMendelssohnstraße 338106 BrunswickGermany Laboratory for Emerging Nanometrology TU BraunschweigBrunswickGermany

Bismuth containing nanomaterials recently received increasing attention with respect to environmental applications because of their low cost, high stability and nontoxicity. In this work, Bi–Bi_2O_2CO_3 heterojunctions were fabricated by in-situ decoration of Bi nanoparticles on Bi_2O_2CO_3 nanosheets via a simple hydrothermal synthesis approach. X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM) and high-resolution TEM(HRTEM) were used to confirm the morphology of the nanosheet-like heterostructure of the Bi–Bi_2O_2CO_3 composite. Detailed ultrafast electronic spectroscopy reveals that the in-situ decoration of Bi nanoparticles on Bi_2O_2CO_3 nanosheets exhibit a dramatically enhanced electron-hole pair separation rate, which results in an extraordinarily high photocatalytic activity for the degradation of a model organic dye, methylene blue(MB) under visible light illumination. Cycling experiments revealed a good photochemical stability of the Bi–Bi_2O_2CO_3 heterojunction under repeated irradiation. Photocurrent measurements further indicated that the heterojunction incredibly enhanced the charge generation and suppressed the charge recombination of photogenerated electron-hole pairs.

关键词： Bi nanoparticles Bi–Bi2O2CO3 nanosheets Heterojunction Hydrothermal method Charge separation Visible light photocatalytic activity

Implementation of High-Q Embedded Band Pass Filter in Wireless Communication

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Intelligent Automation & Soft Computing 2023年第5期36卷 2191-2200页

作者： V.Satheesh kumar S.ramesh Department of Electronics and Communication Engineering T.J.S Engineering CollegeChennaiTamilNadu601206India Valliammai Engineering College ChennaiTamil Nadu603203India

At 12.8 MHz center frequency,the advanced miniaturized polymer-based planar high quality factor(Q)passive elements embedded bandpassﬁlter works in the *** most of the demands operate inside the spectrum,the wideband or high-speed operation necessary to enhance must be acquired in microwave frequency *** channel has a quiet,high-performance micro-ﬁlter with wideband *** and inductors are used in the high quality factor(Q)passive components,and related networks are incorporated in theﬁ*** layers are concatenated using Three-Dimensional Integrated Circuit(3D-IC)integration,parasitics are removed,and interconnection losses are negotiated using de-embedding methods.A wireless application-based Liquid Crystalline Polymer(LCP)viewpoint is employed as a substrate material in this *** polymer processes,their properties,and the incorporated high-Q Band Pass Filter *** suggestedﬁlter model is computed and manufactured utilizing the L-band frequency spectrum,decreasing total physical length by 31%while increasing bandwidth by 45%.

关键词： Bandpassﬁlter wireless communication frequency spectrum embedded technology

Structural,Wettability and Optical Investigation of Titanium Oxynitride Coatings:Effect of Various Sputtering Parameters

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Journal of Materials Science & Technology 2012年第6期28卷 512-523页

作者： Sushant K Rawal Amit kumar Chawla R.Jayaganthan ramesh Chandra Centre of Nanotechnology Indian Institute of Technology RoorkeeRoorkee-247667India Nano Science Laboratory Institute Instrumentation CentreIndian Institute of Technology RoorkeeRoorkee-247667India Department of Mechanical Engineering Charotar University of Science and TechnologyChanga 388421India Department of Physics University of Petroleum and Energy StudiesDehradun-48007India Department of Metallurgical and Materials Engineering Indian Institute of Technology RoorkeeRoorkee-247667India

The objective of the present work is to investigate the effect of various sputtering parameters such as nitrogen flow rate, deposition time and sputtering pressure on structural, wettability and optical properties of titanium oxynitride films deposited on glass substrate by reactive magnetron sputtering. The X-ray diffraction graphs of titanium oxynitride films show evolution of various textures of TiO=N and TiN phases with increasing nitrogen flow rate and deposition time, but an increase in sputtering pressure from 4.0 to 8.0 Pa results in decline of various textures observed for TiO=Ny and TiN phases. The stress and strain calculated by sin2~ method are compressive, which decrease with increasing nitrogen flow rate from 55 to I00 sccm （standard cubic centimeter per minute） and increase with increasing deposition time from 80 to I40 min due to atomic penning effect and increasing thickness of the deposited films. The titanium oxynitride films have contact angle values above 90 deg., indicating that films are hydrophobic. The maximum contact angle of I09.1 deg. is observed at deposition time of 140 min. This water repellent property can add value to potential protective, wear and corrosion resistant application of titanium oxynitride films. The band gap decreases from 1.98 to 1.83 eV as nitrogen flow rate is increased from 55 to 100 sccm; it decreases from 1.93 to 1.79 eV as deposition time is increased from 80 to 140 min as more nitrogen incorporation results in higher negative potential of valence band N2p orbital. But it increases from 2.26 to 2.34 eV for titanium oxynitride films as sputtering pressure increases from 4.0 to 8.0 Pa.

关键词： Titanium oxynitride Sputtering parameters Contact angle Optical properties

Measurement of bit-rock interface temperature and wear rate of the tungsten carbide drill bit during rotary drilling

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Friction 2020年第6期8卷 1073-1082页

作者： Vijay kumar SHANKAR Bijay Mihir KUNAR Chivukula Suryanarayana MURTHY M R ramesh Department of Mining Engineering National Institute of Technology KarnatakaSurathkal 575025India Department of Mechanical Engineering National Institute of Technology KarnatakaSurathkal 575025India

Rock drilling is an essential operation in mining *** at the bit-rock interface plays a major role in the wear rate of the drill *** paper primarily focuses on the wear rate of tungsten carbide(WC)drill bit and the interrelationship between temperature and wear rate during rotary drilling operations conducted using a computer numerical control(CNC)*** interrelationship between the temperature and wear rate was studied with regard to three types of rock samples,i.e.,fine-grained sandstone(FG)of uniaxial compressive strength(UCS)that is 17.83 MPa,medium-grained sandstone(MG)of UCS that is 13.70 MPa,and fine-grained sandstone pink(FGP)of UCS that is 51.67 *** rate of the drill bit has been measured using controlled parameters,i.e.,drill bit diameter(6,8,10,12,and 16 mm),spindle speed(250,300,350,400,and 450 rpm),and penetration rate(2,4,6,8,and 10 mm/min),***,a fully instrumented laboratory drilling set-up was *** weight of each bit was measured after the bit reached 30 mm depth in each type of the rock ***,effects of the bit-rock interface temperature and operational parameters on wear rate of the drill bits were *** results show that the wear rate of drill bits increased with an increase in temperature for all the bit-rock combinations *** is due to the silica content of the rock sample,which leads to an increase in the frictional heat between the bit-rock ***,in case of medium-grained sandstone,the weight percentage(wt%)of SiO2 is around 7.23 wt%,which presents a very low wear rate coefficient of 6.33×10^–2 mg/(N?m).Moreover,the temperature rise during drilling is also minimum,i.e.,around 74℃,in comparison to that of fine-grained sandstone and fine-grained sandstone *** addition,this paper develops the relationship between temperature and wear rate characteristics by employing simple linear regression analysis.

关键词： temperature wear rate drilling simple linear regression

Slope stability analysis of Balia Nala landslide, Kumaun Lesser Himalaya, Nainital, Uttarakhand, India

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第1期9卷 150-158页

作者： Mohit kumar Shruti Rana Pitamber Dutt Pant ramesh Chandra Patel Department of Geology Kumaun University Department of Geophysics Kurukshetra University

Balia Nala is the outlet of the Nainital lake, flowing towards southeast direction. Presence of Nainital habitation at its right bank has high socio-economic importance. This study presents the stability analysis of a ravine/valley along Balia Nala. Variegated slates(lower Krol and upper Blaini formations) are the main rock types, wherever the outcrop does exist and rest of the area is covered by slope wash and river borne materials. Three sets of joints are presented in the area, but 4 sets of joints also exist at some locations. Nainital lake fault intersected by Manora fault from southwest direction passes through eastern side of the study area, and some small faults, which are sub-branches of Nainital lake fault, are observed(with 10 m offset) and promote the landslide in the area. This study shows that different kinds of discontinuities(joints, faults and shear zones) and rapid down cutting by the stream due to neotectonic activity affect the stability of the slope. The fragile lithology and deep V-shaped valley further accelerate the mass movement in the study area. In addition, rock mass rating(RMR), factor of safety(FOS) and graphical analysis of the joints indicate the study area as landslide-prone zone. This study will be helpful in not only reducing the risk on life of people, but also in assisting the ongoing civil work in the study area.

关键词： Rock mass rating(RMR) Factor of safety(FOS) Balia Nala landslide Slope stability analysis

User Centric Block-Level Attribute Based Encryption in Cloud Using Blockchains

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Computer Systems Science & Engineering 2022年第8期42卷 605-618页

作者： S.Godfrey Winster A.Siva kumar R.ramesh Department of Computer Science and Engineering School of ComputingCollege of Engineering and TechnologySRM Institute of Science and TechnologyChengalpattu603203India Department of Information Technology Sri Sai Ram Engineering CollegeChennai600044India Department of Electronics and Communication Engineering Saveetha Engineering CollegeChennai602105India

Cloud computing is a collection of distributed storage Network which can provide various services and store the data in the efficient *** advantages of cloud computing is its remote access where data can accessed in real time using Remote Method Innovation(RMI).The problem of data security in cloud environment is a major concern since the data can be accessed by any time by any *** to the lack of providing the efficient security the cloud computing they fail to achieve higher performance in providing the efficient *** improve the performance in data security,the block chains are used for securing the data in the cloud ***,the traditional block chain technique are not suitable to provide efficient security to the cloud data stored in the *** this paper,an efficient user centric block level Attribute Based Encryption(UCBL-ABE)scheme is presented to provide the efficient security of cloud data in cloud *** proposed approach performs data transaction by employing the block *** proposed system provides efficient privacy with access control to the user access according to the behavior of cloud user using Data Level Access Trust(DLAT).Based on DLAT,the user access has been restricted in the cloud *** proposed protocol is implemented in real time using Java programming language and uses IBM *** implementation results justifies that the proposed system can able to provide efficient security to the data present in and cloud and also enhances the cloud performance.

关键词： Cloud blockchain data security ABE block-level