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Journal of Magnesium and Alloys 2024年第1期12卷 394-404页

作者： Lokesh Choudhary Parama Chakraborty Banerjee r.k.singh raman Derrek E.Lobo Christopher D.Easton Mainak Majumder Frank Witte Jörg F.Löffler Department of Mechanical and Aerospace Engineering Monash UniversityClayton CampusMelbourneVIC 3800Australia Department of Chemical and Biological Engineering Monash UniversityClayton CampusMelbourneVIC 3800Australia Nanoscale Science and Engineering Laboratory(NSEL) Bldg 37Monash UniversityClayton CampusMelbourneVIC 3800Australia CSIrO Materials Science and Engineering Bayview AvenueClaytonVIC 3168Australia Julius Wolff Institute and Berlin Brandenburg Center for regenerative Therapies Charité–Universitätsmedizin BerlinAugustenburger Platz 113353 BerlinGermany Laboratory of Metal Physics and Technology Department of MaterialsETH Zurich8093 ZurichSwitzerland

Biodegradable implants are critical for regenerative orthopaedic procedures,but they may suffer from too fast corrosion in human-body *** necessitates the synthesis of a suitable coating that may improve the corrosion resistance of these implants without compromising their mechanical *** this study,an AZ91 magnesium alloy,as a representative for a biodegradable Mg implant material,was modified with a thin reduced graphene oxide(rGO)-calcium carbonate(CaCO_(3))composite *** analytical and in-vitro electrochemical characterization reveals that this coating significantly improves the corrosion resistance and mechanical integrity,and thus has the potential to greatly extend the related application field.

关键词： Graphene coating Biodegradable implant Hydroxyapatite Corrosion Magnesium alloy

Graphene coatings for corrosion resistance of nickel and copper in acidic,alkaline and neutral environments

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Journal of Materials Science & Technology 2023年第11期142卷 124-133页

作者： r.k.singh raman Abhishek kumar Arya kevin Tomy Faisal A Dip Evelyn Lai Saad Al-Saadi Department of Mechanical&Aerospace Engineering Monash UniversityVic 3800Australia Department of Chemical&Biological Engineering Monash UniversityVic 3800Australia

Graphene coatings have been reported to provide impressive corrosion resistance to nickel(Ni)and copper(Cu),because of remarkable characteristics of inertness and impermeablity of ***,as the earlier investigations have generally been carried out in chloride environment,and it is important to understand the performance of graphene coating also in more aggressive environments such as acids and *** study investigated the electrochemical corrosion behaviour of bare and graphene-coated(by chemical vapour deposition(CVD))Ni and Cu in 0.5 M H_(2)SO_(4),0.1 M NaCl and 0.5 M NaOH *** tests and post corrosion characterisation revealed the improvement in the corrosion resistance of Ni due to multilayer graphene coating to be similar in the three solutions,i.e.,the robustness of the barrier property of the multilayer graphene is largely unaffected by the aggressiveness of the corrosive ***,the improvement in corrosion resistance of bare Ni due to multilayer graphene is considerably greater(nearly 3 orders of magnitude)in the most aggressive of the test solutions(0.5 M H_(2)SO_(4)).The improvement is considerably less in 0.5 M NaOH because bare Ni develops a robust passive layer in highly alkaline *** improvement in corrosion resistance of bare Cu is limited(within an order of magnitude)in the three solutions because Cu develops only 1-2 layers of graphene.

关键词： CVD graphene coatings Electrochemical impedance spectroscopy(EIS) Potentiodynamic polarization(PDP) raman spectroscopy

Multifunctional, Sustainable, and Biological Non-Ureolytic Self-Healing Systems for Cement-Based Materials

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Engineering 2022年第6期8卷 217-237页

作者： Mohammad Fahimizadeh Pooria Pasbakhsh Lee Sui Mae Joash Ban Lee Tan r.k.singh raman School of Engineering Monash University MalaysiaBandar Sunway 47500Malaysia School of Science Monash University MalaysiaBandar Sunway 47500Malaysia Tropical Medicine and Biology Multidisciplinary Platform Monash University MalaysiaBandar Sunway 47500Malaysia Department of Chemical Engineering&Department of Mechanical and Aerospace Engineering Monash UniversityClaytonVIC 3168Australia

Microbially induced calcium carbonate(CaCO_(3))precipitation(MICP)has been investigated as a sustain-able alternative to conventional concrete remediation methods for improving the mechanical properties and durability of concrete *** date,urea-dependent MICP is the most widely employed MICP pathway in biological self-healing concrete research as its use has resulted in efficient CaCO_(3) precipita-tion ***_(3) is a byproduct of ureolysis,and can be hazardous to cementitious structures and the health of various ***,non-ureolytic bacterial concrete self-healing systems have been developed as eco-friendly alternatives to urea-dependent self-healing ***-ureolytic pathways can improve the physical properties of concrete samples and incorporate the use of waste materials;they have the potential to be cost-effective and ***,they can be applied in terrestrial and marine *** date,research on non-ureolytic concrete self-healing systems has been scarce compared to that on ureolytic *** article discusses the advances and challenges in non-ureolytic bacterial concrete self-healing studies and highlights the directions for future research.

关键词： Self-healing concrete Mechanical properties Durability Non-ureolytic pathways Cement composite Sustainability

MHD free convective flow past semi-infinite vertical permeable wall

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Applied Mathematics and Mechanics(English Edition) 2012年第9期33卷 1207-1222页

作者： r.k.singh A.k.singh Department of Mathematics Banaras Hindu University

In this paper, the basic equations governing the flow and heat transfer of an incompressible viscous and electrically conducting fluid past a semi-infinite vertical per- meable plate in the form of partial differential equations are reduced to a set of non-linear ordinary differential equations by applying a suitable similarity transformation. Approx- imate solutions of the transformed equations are obtained by employing the perturbation method for two cases, i.e., small and large values of the suction parameter. From the numerical evaluations of the solution, it can be seen that the velocity field at any point decreases as the values of the magnetic and suction parameters increase. The effect of the magnetic parameter is to increase the thermM boundary layer. It is also found that the velocity and temperature fields decrease with the increase in the sink parameter.

关键词： magnetohydrodynamics (MHD) suction source/sink Prandtl number permeability boundary layer

Effect of induced magnetic field on natural convection in vertical concentric annuli

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Acta Mechanica Sinica 2012年第2期28卷 315-323页

作者： r.k.singh A.k.singh Department of Mathematics Central University of BiharPatnaIndia Department of Mathematics Banaras Hindu UniversityVaranasiIndia

In the present paper, we have considered the steady fully developed laminar natural convective flow in open ended vertical concentric annuli in the presence of a ra- dial magnetic field. The induced magnetic field produced by the motion of an electrically conducting fluid is taken into account. The transport equations concerned with the con- sidered model are first recast in the non-dimensional form and then unified analytical solutions for the velocity, induced magnetic field and temperature field are obtained for the cases of isothermal and constant heat flux on the inner cylin- der of concentric annuli. The effects of the various phys- ical parameters appearing into the model are demonstrated through graphs and tables. It is found that the magnitude of maximum value of the fluid velocity as well as induced magnetic field is greater in the case of isothermal condition compared with the constant heat flux case when the gap be- tween the cylinders is less or equal to 1.70 times the radius of inner cylinder, while reverse trend occurs when the gap between the cylinders is greater than 1.71 times the radius of inner cylinder. These fields are almost the same when the gap between the cylinders is equal to 1.71 times the radius of inner cylinder for both the cases. It is also found that as the Hartmann number increases, there is a flattening ten- dency for both the velocity and the induced magnetic field. The influence of the induced magnetic field is to increase the velocity profiles.

关键词： Natural convection Isothermal Heat flux Skin-friction Induced magnetic field Magnetohydrody- namics

Systematic study of the(n,2n)reaction cross section for^(121)Sb and^(123)Sb isotopes

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Chinese Physics C 2022年第5期46卷 77-94页

作者： r.k.singh N.L.singh r.D.Chauhan Mayur Mehta S.V.Suryanarayana rajnikant Makwana B.k.Nayak H.Naik Tarak Nath Nag k.katovsky Department of Physics Faculty of Sciencethe M.S.University of BarodaVadodara-390002INDIA Department of Physics Netaji Subhas University of TechnologyDwarkaNew Delhi-110078INDIA Institute for Plasma research Gandhinagar-382428INDIA Nuclear Physics Division Bhabha Atomic Research CentreMumbaiINDIA radiochemistry Division Bhabha Atomic Research CentreMumbaiINDIA Department of Electrical Power Engineering Brno University of TechnologyBrno-61600Czech Republic

The cross sections of the^(121)Sb(n,2n)^(120)Sb^(m) and ^(123)Sb(n,2n)^(122)Sb reactions were measured at 12.50,15.79 and 18.87 MeV neutron energies relative to the standard ^(27)Al(n,α)^(24)Na monitor reaction using neutron activation and offline γ-ray *** of the samples was performed at the BArC-TIFr Pelletron Linac Facility,Mumbai,*** quasi-monoenergetic neutrons were generated via the ^(7)Li(p,n)*** model calculations were performed by nuclear reaction codes TALYS(ver.1.9)and EMPIrE(ver.3.2.2)using various input parameters and nuclear level density *** cross sections of the ground and the isomeric state as well as the isomeric cross section ratio were studied theoretically from reaction threshold to 26 MeV *** effect of pre-equilibrium emission is also discussed in detail using different theoretical *** present measured cross sections were discussed and compared with the reported experimental data and evaluation data of the JEFF-3.3,ENDF/B-VIII.0,JENDL/AD-2017 and TENDL-2019 libraries.A detailed analysis of the uncertainties in the measured cross section data was performed using the covariance analysis ***,a systematic study of the(n,2n)reaction cross section for^(121)Sb and^(123)Sb isotopes was also performed within 14-15 MeV neutron energies using various systematic *** work helps to overcome discrepancies in Sb data and illustrate a better understanding of pre-equilibrium emission in the(n,2n)reaction channel.

关键词： antimony (n,2n)reaction cross section 7Li(p,n)reaction neutron source neutron activation and offlineγ-ray spectrometry systematic formulae covariance analysis TALYS(ver.1.9)and EMPIrE(ver.3.2.2)codes

Fuzzy AHP approach for legal judgement summarization

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Journal of Management Analytics 2019年第3期6卷 323-340页

作者： Neha Bansal Arun Sharma r.k.singh Department of Information Technology Indira Gandhi Delhi Technical University for WomenDelhiIndia

Legal documents are generally big and complex documents because of specific vocabulary,semantics and *** of the major challenges in legal processing systems is to generate summary of legal *** date,in most of the legal systems,the summary of judgements is produced manually by legal experts which are then used by Lawyers,Judges and other legal *** manual process of summarization is very inefficient and *** text summarization(ATS)is the process of reducing the content of a textual document,while retaining the core description of text through the use of appropriate *** present work proposes a novel Fuzzy Analytical Hierarchical process(FAHP)based feature weighting scheme which helps in producing an efficient and effective summary of legal *** is applied on a number of legal judgements taken from Indian IT *** of the model is done using rOUGE(recall-Oriented Understudy for Gisting Evaluation)tool with recall,precision,and f-measure as performance *** generated summaries are further assessed by legal experts and are found to be more promising than the summaries generated by traditional approaches.

关键词： summarization fuzzy AHP feature extraction feature weighting legal information system legal knowledge management social science

Impact of source and drain contact thickness on the performance of organic thin film transistors

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Journal of Semiconductors 2014年第12期35卷 21-27页

作者： Poornima Mittal Y.S.Negi r.k.singh Department of Electronics & Communication Engineering Graphic Era UniversityDehradun–248002 India Department of Electronics & Communication Engineering Uttarakhand Technical UniversityDehradun–248002 India Department of Polymer and Process Engineering Indian Institute of Technology Roorkee–246776 India

This paper analyzes the impact of source（ts） and drain（td） contact thicknesses on top contact（TC） and bottom contact（BC） organic thin film transistors（OTFTs） with a gate in the bottom, using a benchmarked industry standard Atlas 2-D numerical device simulator. The parameters including drive current（Ids）, mobility（μ）, threshold voltage（Vt）and current on-off ratio（ION/IOFF） are analyzed from the device physics point of view on different electrode thicknesses, ranging from infinitesimal to 50 nm, for both top and bottom contact structures. Observations demonstrate that the performance of the BC structure is more affected by scaling of ts=din comparison to its counterpart. In the linear region, the mobility is almost constant at all the values of ts=dfor both structures. However,an increment of 18% and 83% in saturation region mobility is found for TC andBC structures, respectively with scaling down ts=dfrom 50–0 nm. Besides this, the current on-off ratio increases more sharply in the BC *** analysis simplifies a number of issues related to the design and fabrication of organic material based devices and circuits.

关键词： contact thickness organic semiconductor organic thin film transistor bottom contact top contact structure

Augmented growth of long pepper in response to arbuscular mycorrhizal inoculation

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Journal of Forestry research 2012年第2期23卷 339-344页

作者： r.k.singh P.Gogoi Department of Botany Rajiv Gandhi UniversityItanagar-791112India krishi Vigyan kendra-Sylvan Hengbung villageKangpokpi-795129India

Arbuscular mycorrhizal （AM） technology is a soil-based fertilization practice for sustainable crop productivity. We evaluated six indigenous Arbuscular mycorrhizal fungi （AMF） strains for their symbiotic response with Piper longum （long pepper）, a non-timber forest product holding promise as a commercial crop for its medicinal fruits and roots. Piper saplings were raised in a 10 cm thick sand and soil mix inoculated with various AMF. Under field conditions, plants inoculated with AMF demonstrated better survival （〉80%） than non mycorrhizal plants （58%）. Almost all the studied AMF strains increased the plant growth, biomass and nutrient content （N and P） over the uninoculated control. Mycorrhizal inoculation with four AMF species, viz： Glomus fasciculatum, G. clarum, G. etunicatum and G. versiforme greatly enhanced long pepper growth both in the nursery and field conditions.

关键词： Piper longum Arbuscular mycorrhizal fungi Survival Growth non-timber forest product

Gate leakage current reduction in IP3 SrAM cells at 45 nm CMOS technology for multimedia applications

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Journal of Semiconductors 2012年第5期33卷 88-92页

作者： r.k.singh Neeraj kr.Shukla Manisha Pattanaik Bipin Tripathi kumaon Institute of Technology DwarahatAlmora(Uttarakhand)India ITM University Department of EECEGurgaon(Haryana)India ABV-IIITM VLSI GroupDepartment of ITGwalior(Madhya Pradesh)India

We have presented an analysis of the gate leakage current of the IP3 static random access memory （SrAM） cell structure when the cell is in idle mode（performs no data read/write operations） and active mode （performs data read/write operations）,along with the requirements for the overall standby leakage power,active write and read powers.A comparison has been drawn with existing SrAM cell structures,the conventional 6T,PP, P4 and P3 *** the supply voltage,V_（DD） = 0.8 V,a reduction of 98%,99%,92%and 94%is observed in the gate leakage current in comparison with the 6T,PP,P4 and P3 SrAM cells,respectively,while at V_（DD） = 0.7 V,it is 97%,98%,87%and 84%.A significant reduction is also observed in the overall standby leakage power by 56%〉, the active write power by 44%and the active read power by 99%,compared with the conventional 6T SrAM cell at V_（DD）= 0.8 V,with no loss in cell stability and performance with a small area *** simulation environment used for this work is 45 nm deep sub-micron complementary metal oxide semiconductor（CMOS） technology,t_（ox） = 2.4 nm,k_（thn） = 0.22 V,k_（thp） = 0.224 V,V_（DD） = 0.7 V and 0.8 V,at T = 300 k.

关键词： gate leakage subthreshold leakage low power deep sub-micron SrAM