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最小量润滑下搅拌摩擦焊接AA2014合金的组织与力学性能

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Journal of Central South University 2023年第4期30卷 1047-1063页

作者： MYSTICA A. SENTHIL kumar v.S. Department of Mechanical Engineering CEGAnna UniversityTamilnaduIndia

搅拌摩擦焊(FSW)的余热溶解析出相降低了沉淀强化AA2014合金的接头质量。本研究采用最小量润滑(MQL)技术来散热,将采用两步法制备的石墨烯纳米流体作为冷却剂,用光学显微镜、扫描电镜、透射电镜、X射线衍射和差示扫描量热法研究晶粒结... 详细信息

搅拌摩擦焊(FSW)的余热溶解析出相降低了沉淀强化AA2014合金的接头质量。本研究采用最小量润滑(MQL)技术来散热,将采用两步法制备的石墨烯纳米流体作为冷却剂,用光学显微镜、扫描电镜、透射电镜、X射线衍射和差示扫描量热法研究晶粒结构和析出相的发展。结果表明,在不同转速和焊接速度组合下,不同的热循环对析出相的转变不同,从而对焊缝性能产生调节作用,成功消除无沉淀析出带的形成。采用n-MQL技术产生了稳定的θ相,从而使焊接接头有更高的焊接性能。在1200 r/min的转速和72 mm/min的焊接速度下,建立了具有优异性能的工艺窗口。

关键词：搅拌摩擦焊最少润滑量石墨烯纳米流体 AA2014合金析出相

Stability Analysis of DC Microgrid Clusters Based on Step-by-step System Matrix Building Algorithm

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 900-912页

作者： K.Jithin N.Mayadevi R.Hari kumar v.P.Mini the Department of Electrical Engineering College of Engineering TrivandrumAPJ Abdul Kalam Technological University(APJAKTU)ThiruvananthapuramIndia

DC microgrids(DCMGs)are made up of a network of sources and loads that are connected by a number of power electronic converters(PECs).The increase in the number of these PECs instigates major concerns in system *** interconnecting the microgrids to form a cluster,the system stability must be *** paper proposes a novel stepby-step system matrix building(SMB)algorithm to update the system matrix of an existing DCMG cluster when a new microgrid is added to the cluster through a distribution *** stability of the individual DCMGs and the DCMG cluster is analyzed using the eigenvalue ***,the particle swarm optimization(PSO)algorithm is used to retune the controller gains if the newly formed cluster is not *** simulation of the DCMG cluster is carried out in MATLAB/Simulink environment to test the proposed *** results are also validated using the OP4510 real-time simulator(RTS).

关键词： Converter DC microgrid cluster eigenvalue interconnection particle swarm optimization system stability system matrix

Effect of temperature dependent viscosity on revolving axi-symmetric ferrofluid flow with heat transfer

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Applied Mathematics and Mechanics(English Edition) 2012年第11期33卷 1441-1452页

作者： P. RAM v. kumar Department of Mathematics National Institute of TechnologyKurukshetra Haryana 136119 India

The prime objective of the present study is to examine the effect of tempera- ture dependent viscosity/z（T） on the revolving axi-symmetric laminar boundary layer flow of an incompressible, electrically non-conducting ferrofiuid in the presence of a stationary plate subjected to a magnetic field and maintained at a uniform temperature. To serve this purpose, the non-linear coupled partial differential equations are firstly converted into the ordinary differential equations using well-known similarity transformations. The popular finite difference method is employed to discretize the non-linear coupled differ- ential equations. These discretized equations are then solved using the Newton method in MATLAB, for which an initial guess is made with the help of the Flex PDE Solver. Along with the velocity profiles, the effects of temperature dependent viscosity are also examined on the skin friction, the heat transfer, and the boundary layer displacement thickness. The obtained results are presented numerically as well as graphically.

关键词： ferrofluid temperature dependent viscosity boundary layer axi-symmetry,magnetic field

Cu（OTf）2 Catalyzed Synthesis of Bis（5-methyl-2-furyl）methanes by Condensation of 2-Methylfuran with Carbonyl Compounds under Solvent Free Conditions

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Chinese Journal of Chemistry 2011年第7期29卷 1483-1488页

作者： Muthyala, Manoj kumar Rao, v. Kameswara kumar, Anil Department of Chemistry Birla Institute of Technology and Science Pilani 333 031 India

A facile and efficient one-pot three-component synthesis of bis（5-methyl-2-furyl）methanes has been achieved via the reaction of 2-methylfuran with a series of aliphatic and aromatic aldehydes and aliphatic ketones in presence of copper（II） triflate under solvent free conditions. The bis（5-methyl-2-furyl）methanes were obtained in 34%--72% yields and the catalyst was recycled up to four successive cycles without much loss in catalytic activity.

关键词： Lewis acid copper(II) triflate 2-methylfuran bis(5-methyl-2-furyl)methane multicomponent condensation solvent free condition

Antidiabetic and anti-lipemic effects of Cassia siamea leaves extract in streptozotocin induced diabetic rats

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Asian Pacific Journal of Tropical Medicine 2010年第11期3卷 871-873页

作者： S kumar v kumar Om Prakash Institute of Pharmaceutical Sciences Kurukshetra UniversityKurukshetra -136119HaryanaIndia

Objective:To investigate the antidiabetic and anti-lipemic effects of Cassia siamea methanolic leaves ***:The antidiabetic study was performed by measuring blood glucose level with elegance glucometer at weekly intervals i.e.0,7,14 and 21 in normal and streptozotocin induced diabetic *** cholesterol,triglyceride and HDL-cholesterol were determined in normal and streptozotocin induces diabetic rats by *** was used as a reference drug at a dose of 10 mg/***:After the oral administration of extracts at doses of 250 mg/kg and 500 mg/kg for three weeks,blood glucose levels and body weights were significantly improved(Pvel was found to be improved to(Pvel as well as improving lipid metabolism and body weight in rats with induced diabetes.

关键词： Cassia siamea Antidiabetic Anti-lipemic Rat Streptozotocin

Effect of hydrogen plasma treatment on the growth and microstructures of multiwalled carbon nanotubes

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Nano-Micro Letters 2010年第1期2卷 42-48页

作者： S.K.Srivastava v.D.vankar v.kumar Department of Physics Indian Institute of Technology Delhi National Physical Laboratory Dr.K.S.Krishnan Marg

The effect of hydrogen plasma treatment of iron oxide films on the growth and microstructure of carbon nanotubes(CNTs)by microwave plasma enhanced chemical vapor deposition process has been *** plasma was characterized in-situ using optical emission *** of the films was examined by scanning electron *** analysis was carried out by high resolution transmission electron microscopy(HRTEM)equipped with energy dispersive X-ray spectroscopy(EDS)and micro-diffraction *** is found that oxide films without H_2 plasma pretreatment or treated for lesser time resulted in CNT films with high percentage of carbonaceous particles and with embedded particles/nanorods distributed discontinuously in the cavity of the *** embedded particles were found to be of iron carbide(Fe-C)as confirmed by HRTEM,EDS and micro-diffraction *** observations suggested that the iron oxide particles had poor catalytic action for CNT growth and in-situ reduction of oxide clusters to Fe by hydrogen plasma plays a key role in discontinuous filling of the nanotubes by the catalytic particles.

关键词： Carbon nanotubes Chemical vapor deposition Iron carbide MPECvD

Heavy metal pollution of river water and eco-friendly remediation using potent microalgal species

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Water Science and Engineering 2024年第1期17卷 41-50页

作者： Amudham Radha Amal Raj Prabhakaran Mylsamy v.Sivasankar B.Sathish kumar Kiyoshi Omine T.G.Sunitha Phycological Research Laboratory Research Department of BotanyPachaiyappa's College(Affiliated to University of Madras)Chennai 600030India Research Department of Chemistry Pachaiyappa's College(Affiliated to University of Madras)Chennai 600030India Department of Botany Sri Vidya Mandir Arts&Science College(Autonomous)KatteriUthangarai 636902India Department of Civil Engineering School of Engineering.Nagasaki UniversityNagasaki-Daigaku1-14 Bunkyo-machiNagasaki 8528521Japan

Pollution of rivers is mainly caused by anthropogenic activities such as discharge of effluent from industrial facilities,maintenance of sewage/effluent treatment plants,and dumping of solid waste on river *** study dealt with the pollution issues of the Cooum River in the well-known city of Chennai in South *** samples from 27 locations were collected and analyzed for 12 elements,including Ba,B,and Al,as well as heavy metals such as Pb,Cr,Mn,Fe,Co,Ni,Cu,Zn,and *** samples showed levels of these elements that exceeded World Health Organization *** correlation analysis revealed the inter-dependency among elements,and the contribution of each element based on factor loadings showed its percentage contribution compared to *** samples from six significant locations were chosen for remediation with three algae:Chlorella vulgaris,Scenedesmus dimorphus,and Phormedium *** uptake of pollutants led to the continuous growth of algae during the incubation period of 15 d,effectively removing heavy metals from the river *** increasing levels of algal counts and the chlorophyll a content confirmed the algal growth during the incubation period,followed by a declining stage after the incubation *** scanning electron microscopic images of algae before and after the remediation showed no remarkable modification of morphological *** study showed that the uptake of heavy metals using algae is an effective water pollution remediation measure,making the process practicable in the field on a large scale in the near future.

关键词： Heavy metal Cooum river Phycoremediation Microalgae Factor analysis

Ligninolytic enzymes production by endophytic fungus Diaporthe phaseolorum(Desm.)*** the influence of different carbon and nitrogen sources

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Studies in Fungi 2021年第1期6卷 531-542页

作者： kumar v Prasher IB Mycology and Plant Pathology Lab. Department of BotanyPanjab University ChandigarhChandigarh-160014India

Endophytic fungi are being investigated for their ability to create industrially relevant secondary *** recent years,there has been a surge in interest in these fungi as a source of novel enzymes,particularly hydrolytic *** present study investigated the effect of different carbon,organic and inorganic nitrogens on the growth and ligninolytic enzyme production by the endophytic fungus Diaporthe *** fungus was isolated from the leaves of Dillenia indica and analyzed by morpho-molecular *** fungus showed promising results for in vitro production of ligninolytic *** was the most favorable carbon compound for growth among all the carbon compounds *** displayed maximum lignin peroxidase(Lip)activity in fructose(3.5 U/ml),followed by pectin(2.60 U/ml)and glucose(2.53 U/ml).Glucose gave the highest manganese peroxidase(MnP)activity i.e.,6.88 U/ml followed by starch,sucrose and ***,the maximum laccase activity was 44.5 U/ml in *** nitrate and L-asparagine were the best inorganic and organic nitrogen for *** the case of ligninolytic enzyme production,ammonium acetate and ammonium phosphate were the best media for LiP and MnP,whereas laccase production was highest in ammonium nitrate supplemented *** organic nitrogen sources,medium supplemented with DL-tryptophan gave the highest Lip production,whereas MnP and laccase production was observed in the medium containing L-tyrosine and *** the best of our knowledge,this is the first report related to the growth and ligninolytic enzyme production by Diaporthe *** findings from the study will assist researchers in improving the production of ligninolytic enzymes by this fungus under in vitro conditions on an industrial scale.

关键词： Hydrolytic enzymes Industrially In vitro Manganese peroxidase Morpho molecular analysis

Pharmacognostic study and anti-inflammatory activity of Callistemon lanceolatus leaf

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Asian Pacific Journal of Tropical Biomedicine 2011年第3期1卷 177-181页

作者： kumar S kumar v Prakash OM Institute of Pharmaceutical Sciences Kurukshetra University

Objective:To study detail pharmacognosy and anti-inflammatory activity of Callistemon lanceolatus(***) ***:Leaf sample was studied by organoleptic, macroscopical,microscopical,phytochemical and other WHO recommended methods for *** methanolic leaf extract of the plant was also screened for antiinflammatory activity on carrageenan-induced paw edema in rat at doses of 200 and 400 mg/kg, *** detail pharmacognostic study of the *** leaf was carried out to lay down the standards which could be useful in future experimental ***:*** methanolic leaf extract showed significant(Pvity at doses of 200 mg/kg and 400 mg/*** significant anti-inflammatory of *** methanolic leaf extract at the dose of 400 mg/kg was comparable with diclofenac ***:The pharmacognostic profile of the *** leaf is helpful in standardization for quality,purity and sample *** methanolic extract at a dose of 400 mg/kg shows a significant activity in comparison with the standard drug diclofenac sodium(50 mg/kg).

关键词： Anti-inflammatory Callistemon lanceolatus Carragennan Fibre Microscopy Stomata