检索结果-南通市图书馆

sp^(2)碳用于3D打印技术综述:材料、性能和应用

在线全文

学校读者我要写书评

暂无评论

新型炭材料（中英文） 2022年第6期37卷 1046-1065页

作者： Satendra kumar Manoj Goswami Netrapal Singh Sathish Natarajan surender kumar Academy of Scientific and Innovative Research(AcSIR) Ghaziabad 201002India CSIR-Advanced Materials and Processes Research Institute(AMPRI) Bhopal 462026India

3D打印可以改变现有的生产方法,是第四次工程革命中的一项现代技术。它从成型原理上提出了分层制造、逐层叠加成型的新颖生产方法,从根本上简化了制造工艺,实现了大规模定制生产。然而,这一新技术仍存在许多问题。除了纯石墨烯外,sp^(2... 详细信息

3D打印可以改变现有的生产方法,是第四次工程革命中的一项现代技术。它从成型原理上提出了分层制造、逐层叠加成型的新颖生产方法,从根本上简化了制造工艺,实现了大规模定制生产。然而,这一新技术仍存在许多问题。除了纯石墨烯外,sp^(2)碳具有好的亲水性,3D打印难度较小。sp^(2)碳还可在3D打印中的各种阶段应用。纯石墨烯的疏水性使其难以在水系介质中打印和加工。毛细管油墨的发展使得纯石墨烯的3D打印成为可能。本文综述了sp^(2)碳的3D打印技术的最新进展。首先简要概述了3D打印技术,随后概述了sp^(2)碳的3D打印及其在各种方面的应用。最后,讨论了这一新领域的发展前景和机遇。

关键词： 3D打印技术 sp^(2)碳碳基复合材料应用

Modeling the effect of time delay in implementation of mitigation policies on the control of atmospheric greenhouse gases

在线全文

学校读者我要写书评

暂无评论

生物数学学报:英文版 2023年第8期16卷 75-108页

作者： Alok kumar verma Maitri verma Department of Mathematics School of Physical and Decision Science Babasaheb Bhimrao Ambedkar University Lucknow India

Mitigation of the enhanced greenhouse gas(GHG)concentrations in the Earth's atmosphere is imperative to meet the climate change mitigation objective.Governments of many countries are developing and implementing various mitigation strategies to reduce their GHG emissions.However,a time delay between the formulation and implementation of these mitigation policies can affect their effectiveness in controlling greenhouse gas levels in the atmosphere.This work presents a nonlinear mathematical model to investigate the effect of application of mitigation strategies and the delay involved in their implementation over the reduction of atmospheric greenhouse gases.In model formulation,it is assumed that the mitigation strategies work two-fold;first they reduce the GHG emission rate from the anthropogenic source and second they increase the removal rate of greenhouse gas from the atmosphere.A comprehensive stability analysis of the proposed model system is made to examine its long-term behavior.The model analysis shows that an increase in the implementation rate of mitigation strategies and their efficiencies to cut down the GHG emission rate from point sources and increase the GHG uptake rate lead to reduction in equilibrium GHG concentration.It is found that a long delay in the execution of mitigation policies can destabilize the system dynamics and leads to the generation of periodic oscillations.The expression for the threshold value of the delay parameter at which periodic oscillations arise via Hopf-bifurcation is determined.The stability and direction of bifurcating periodic solutions are discussed.A sensitivity analysis is performed to investigate the effect of changes in key parameters over system dynamics.

关键词： Mathematical model greenhouse gases global warming mitigation strategies time delay Hopf-bifurcation

Surface Modification Aspects for Improving Biomedical Properties in Implants:A Review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 213-241页

作者： J.Sharath kumar Rakesh kumar Rajeev verma Industrial and Production Department Dr B R Ambedkar National Institute of Technology JalandharJalandharPunjab144008India

The primary focus during surgery is to ensure successful implantation by achieving long-term and stable fixation of implants.Orthopaedic surgery is now more focused on the development of novel biomaterials intended to improve implant performance.To obtain a better understanding of metal implants,this article investigated the causes of material failures in certain cases and analysed a few case studies.The interaction between the implant and bone tissue was a crucial aspect of successful implantation,and this study explored the factors influencing this interaction as well as ways to improve it.Several modern approaches used for modifying implant surfaces were systematically illustrated and briefly analysed.Thermal spray coatings were often favoured because of their wide range of coating materials,but other substantial surface modifications(such as friction stir processing and laser surface texturing)were also used for a selection of applications.Notably,implant surfaces with desirable features,such as biocompatibility,antibacterial properties,corrosion resistance,and wear resistance,were essential for optimising implant functionality.This systematic review's main aim is to provide exhaustive reference information and a broad overview to advance the production and design of orthopaedic implants.

关键词： Biomaterials Surface treatments Thermal spray coatings Antibacterial Biocompatibility Corrosion resistance Wear resistance

Battery energy storage-based system damping controller for alleviating sub-synchronous oscillations in a DFIG-based wind power plant

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Protection and Control of Modern Power Systems 2023年第2期8卷 260-277页

作者： Neevatika verma Narendra kumar Rajeev kumar Department of Electrical Engineering Delhi Technological UniversityNew DelhiIndia Electrical Engineering Department Jamia Millia IslamiaNew DelhiIndia Electrical and Electronics Engineering Department KIET Group of InstitutionsGhaziabadIndia

This paper presents the issue of the Sub-synchronous resonance(SSR)phenomenon in a series compensated DFIG-based wind power plant and its alleviation using a Battery Energy Storage-based Damping Controller(BESSDCL).A supplementary damping signal is developed considering the angular speed deviation and is incorporated into the BESS control system.Wide-area Measurement System data is used to determine the angular speed deviation.A lin-earized system model is developed to perform eigenvalue analysis,and to detect and examine unstable SSR modes.The variation of wind speed and three-phase fault are also taken into consideration to validate the robustness of the controller.To further verify the efficacy of the proposed damping controller,time-domain simulations are performed using MATLAB/Simulink.The application of the proposed BESSDCL stabilizes all the unstable system modes effectively at wind speeds of 7 m/s,9 m/s,and 11 m/s,and at 40%,50%,and 60%series compensation levels,as well three-phase fault conditions.

关键词： Battery energy storage system Damping controller Doubly-fed induction generator(DFIG) Series

Experimental investigation for machinability aspects of graphene oxide/carbon fiber reinforced polymer nanocomposites and predictive modeling using hybrid approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第5期17卷 1671-1686页

作者： Jogendra kumar Rajesh kumar verma Department of Mechanical Engineering Madan Mohan Malaviya University of TechnologyGorakhpur273010India

This article explores the drilling behavior of polymer nanocomposites reinforced by Graphene oxide/Carbon fiber using a hybrid method of Grey theory and Principal component analysis(GR-PCA).An online digital dynamometer was employed for the evaluation of Thrust Force and Torque.The image processing technique computes the delamination.Response surface methodology(RSM)considers the parameters,namely,drilling speed(S),feed rate(F),Graphene Oxide wt.%(G)in designing the experimentation array.Principal component analysis(PCA)was used to tackle the response priority weight during the combination of multiple functions.Analysis of variance(ANOVA)scrutinized the influence of parameters and intended the regression models to predict the response.GR-PCA evaluated the optimal parametric setting and remarked that feed rate acts as the most predominant factor.The higher feed rate and wt.%of G is responsible for surface damages like fiber pull-out,fiber fracture and cracks.A significant improvement in drilling responses has been obtained and also validates through confirmatory test and microstructure investigations.

关键词： Graphene oxide Polymer Carbon fiber RSM ANOVA GR-PCA

Dynamics of some new solutions to the coupled DSW equations traveling horizontally on the seab e d

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean Engineering and Science 2024年第2期9卷 154-163页

作者： Raj kumar Ravi Shankar verma Department of Mathematics Faculty of Engineering&TechnologyVeer Bahadur Singh Purvanchal UniversityJaunpur 222003India

The system of(1+1)-coupled Drinfel’d-Sokolov-Wilson equations describes the surface gravity waves travelling horizontally on the seabed.The objective of the present research is to construct a new variety of analytical solutions for the system.The invariants are derived with the aid of Killing form by using the optimal algebra classification via Lie symmetry approach.The invariant solutions involve time,space variables,and arbitrary constants.Imposing adequate constraints on arbitrary constants,solutions are represented graphically to make them more applicable in designing sea models.The behavior of solutions shows asymptotic,bell-shaped,bright and dark soliton,bright soliton,parabolic,bright and kink,kink,and periodic nature.The constructed results are novel as the reported results[26,28,29,30,33,38,42,49]can be deduced from the results derived in this study.The remaining solutions derived in this study,are absolutely different from the earlier findings.In this study,the physical character of analytical solutions of the system could aid coastal engineers in creating models of beaches and ports.

关键词： Coupled Drinfel’d-Sokolov-Wilson model Invariants Killing form Optimal sub algebra Lie symmetry reductions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Ocean Engineering and Science 2023年第2期8卷 111-123页

作者： Raj kumar Ravi Shankar verma Atul kumar Tiwari Department of Mathematics Faculty of Engineering&TechnologyVeer Bahadur Singh Purvanchal UniversityJaunpur222003India Department of Mathematics Motihari College of EngineeringMotihari845401BiharIndia

This work is devoted to get a new family of analytical solutions of the(2+1)-coupled dispersive long wave equations propagating in an infinitely long channel with constant depth,and can be observed in an open sea or in wide channels.The solutions are obtained by using the invariance property of the similarity transformations method via one-parameter Lie group theory.The repeated use of the similarity transformations method can transform the system of PDEs into system of ODEs.Under adequate restrictions,the reduced system of ODEs is solved.Numerical simulation is performed to describe the solutions in a physically meaningful way.The profiles of the solutions are simulated by taking an appropriate choice of functions and constants involved therein.In each animation,a frame for dominated behavior is captured.They exhibit elastic multisolitons,single soliton,doubly solitons,stationary,kink and parabolic nature.The results are significant since these have confirmed some of the established results of S.kumar et al.(2020)and K.Sharma et al.(2020).Some of their solutions can be deduced from the results derived in this work.Other results in the existing literature are different from those in this work.

关键词： Dispersive long wave equations Solitons Invariants Lie-group Similarity solutions

Bile acid synthetic defects: Simplified approach in a nutshell

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2020年第1期19卷 80-84页

作者： Aathira Ravindranath Moinak Sen Sarma surender kumar Yachha Department of Pediatric Gastroenterology Sanjay Gandhi Post Graduate Institute of Medical Sciences

Bile acid synthetic defects(BASD)constitute a rare group of disorders with manifestations in children as well as adults.Diagnosing the individual BASD mandates a lucid understanding of the bile acid synthetic pathway.However,the synthesis pathway is complex,consisting of numerous enzymes and intermediate products that are volatile in the physician’s memory.Despite paucity of literature,a simplified approach to the BASD is presented in this paper.

关键词： synthetic simplified approach

A review on emerging materials with focus on BiI_(3) for room-temperature semiconductor radiation detectors

在线全文

学校读者我要写书评

暂无评论

Radiation Detection Technology and Methods 2023年第4期7卷 465-483页

作者： Ritu Chaudhari Chhaya Ravi Kant Alka Garg surender kumar Sharma Department of Applied Sciences and Humanities Indira Gandhi Delhi Technical University for WomenKashmere GateDelhi110006India Gargi College University of DelhiSiri Fort RoadNew Delhi110049India Delhi Skill and Entrepreneurship University New DelhiIndia

Purpose Considerable advances in the fundamental knowledge and applications of radiation science have led to significant progress and development of room-temperature semiconductor radiation detectors(RTSD).The RTSDs technologies are continuously evolving with accelerated research and material engineering in the last decade.Significant scientific and technological advancements have led to development of high-performance radiation detectors with high signal-to-noise ratio(SNR),better sensitivity,faster response and higher-resolution with capability of desired room-temperature operation.This paper is a review on emerging semiconductor radiation detector materials with a deeper insight into the prospective role of Bismuth tri-iodide(BiI_(3))for room-temperature radiation detectors.Methods An introduction of the state of art of most developed semiconductor materials,i.e.,cadmium telluride(CdTe),mercury iodide(HgI_(2)),lead iodide(PbI_(2)),etc.,and a critical examination of properties,shortcomings and challenges related to their synthesis have been elaborated.Polymer-semiconductor composites with desirable properties and their integration into detector devices is also presented.Subsequent sections discuss the role of BiI_(3) as an emerging radiation detector material for room-temperature operation with an in-depth discussion on the role of defects in charge transportation and electrode configuration.Furthermore,the current challenges along with the future prospects of these materials for radiation detection to promote continuous innovation and practical applications are also elaborated.Conclusion The comprehensive review on latest developments in room-temperature radiation detector materials is expected to help establish a technological roadmap for the synthesis,fabrication and commercialization of novel materials for development of efficient radiation detectors.

关键词： Radiation detector Defects Electrical properties Bismuth tri-iodide Semiconductor Toxicity