检索结果-南通市图书馆

Journal of Materials Science & Technology 2021年第2期61卷 234-246页

作者： Hu Liu Jie Wei Junhua Dong Yiqing Chen Yumin Wu Yangtao Zhou subedi dhruba babu Wei Ke Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China State Key Laboratory of Metal Material fo r Marine Equipment and Application Anshan114009China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

The corrosion behavior of the as-received steel and the spheroidized steel in acidic chloride environment was investigated. The results indicate the corrosion mode and corrosion rate of two steels are diverse due to their difference in microstructure. For as-received steel with ferrite-pearlite microstructure, severe localized corrosion happens on the pearlite regions, and plenty of cathodic cementite remains in the pits, further strengthening the micro-galvanic effect and accelerating the corrosion rate. While for spheroidized steel with tempered martensite microstructure, the nanosized cementite particles evenly distributed on the ferrite substrate are easy to fall off, which can significantly reduce the cementite accumulation on the steel surface, relieving the acceleration effect of micro-galvanic corrosion.

关键词： Ferrite-pearlite steel Acidic chloride environment Granular cementite Micro-galvanic corrosion

The synergy between cementite spheroidization and Cu alloying on the corrosion resistance of ferrite-pearlite steel in acidic chloride solution

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第25期84卷 65-75页

作者： Hu Liu Jie Wei Junhua Dong Yangtao Zhou Yiqing Chen Yumin Wu subedi dhruba babu Aniefiok Joseph Umoh Wei Ke Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China State Key Laboratory of Metal Material for Marine Equipment and Application Anshan114009China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China

In this work,the corrosion behavior of medium-carbon steels(45,45 Cu and 45 Cuq steels)in acidic chloride environment was investigated.The results indicated that the micro-galvanic effect between the anodic ferrite matrix phase and the cathodic cementite secondary phase notably affected the corrosion resistance of the three steels.For 45 steel,serious pitting corrosion happened in and around the pearlite regions,and a large number of lamellar cementite was fixed in the corrosion pits.Meanwhile,the continuously increasing superficial area of cathodic cementite enhanced the micro-galvanic corrosion,resulting in a rapidly increase in corrosion rate with time.While for 45 Cu and 45 Cuq steels,macroscopic uniform corrosion occurred,and the cementite accumulation was markedly reduced as compared with 45 steel,thus the micro-galvanic effect was weakened and the corrosion rate was decreased accordingly.Among these,45 Cuq steel showed the most stable and excellent corrosion resistance during long-term corrosion,indicating the occurrence of a synergistic effect between cementite spheroidization and Cu alloying,thereby significantly improving the corrosion resistance of 45 steel.

关键词： Cementite spheroidization Cu alloying Ferrite-pearlite steel Micro-galvanic effect

Phase structures and critical behavior of rational non-linear electrodynamics Anti de Sitter black holes in Rastall gravity

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第4期76卷 134-152页

作者： Yassine Sekhmani dhruba Jyoti Gogoi Ratbay Myrzakulov Javlon Rayimbaev Ratbay Myrzakulov Eurasian International Centre for Theoretical Physics Astana 010009Kazakhstan L.N.Gumilyov Eurasian National University Astana 010008Kazakhstan Department of Physics Moran CollegeMoranhatCharaideo 785670AssamIndia Theoretical Physics Division Centre for Atmospheric StudiesDibrugarh UniversityDibrugarh 786004AssamIndia New Uzbekistan University Movarounnahr Str.1Tashkent 100000Uzbekistan University of Tashkent for Applied Sciences Gavhar Str.1Tashkent 100149Uzbekistan National University of Uzbekistan Tashkent 100174Uzbekistan

This research paper presents a black hole solution with a rational nonlinear electrodynamics source within the Rastall gravity framework.The paper analyzes the thermodynamic properties of the solution in normal phase space and explores its critical behavior.The phase structure is examined using the extended first law of thermodynamics,with the cosmological constantΛserving as pressure P.The isotherms exhibit van der Waals behavior at small values of horizon r_(+).The paper also investigates the Gibbs free energy behavior and finds two critical points with two pressures where the re-entrant phase transition occurs and disappears.We also explore the prevalent microstructure of black holes in Ruppeiner geometry,uncovering significant deviations in the nature of particle interactions from conventional practice.Moreover,the thermodynamic geometry is analyzed using the Ruppeiner formalism,with the normalized Ricci scalar indicating possible point-phase transitions of the heat capacity,and the normalized extrinsic curvature having the same sign as the normalized Ricci scalar.The three-phase transitions of the heat capacity are those that we find for the normalized Ruppeiner curvatures.Thus,there is an absolute correspondence.

关键词： Rastall gravity biack hole Phase structures

Effect of D-fructose on the in-vitro corrosion behavior of AZ31 magnesium alloy in simulated body fluid

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第7期66卷 202-212页

作者： Durga Bhakta Pokharel Liping Wu Junhua Dong Xin Wei Ini-Ibehe Nabuk Etim dhruba babu subedi Aniefiok Joseph Umoh Wei Ke Shenyang National Laboratory for Materials Science(SYNL) Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Material Science and Engineering University of Science and Technology of ChinaHefei230026China Department of Marine Biology Akwa Ibom State UniversityUyoNigeria

The effect of addingd-fructose to simulated body fluid(SBF) on the corrosion behavior of AZ31 magnesium(Mg) alloy at 37.C and at a pH of 7.4 was studied by potentiodynamic polarization(PDP), electrochemical impedance spectroscopy(EIS), potentiostatic polarization and hydrogen(H2) collecting techniques,Raman spectroscopy technique, scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), X-ray diffraction(XRD), X-ray photoelectron spectroscopy analysis(XPS) and Fourier transformed infrared(FTIR). The results demonstrated that the addition of fructose enhanced the deposition of phosphates forming thick and compact corrosion products, which inhibited the transmission of aggressive ions into the Mg substrate. As a result, both the anodic dissolution of Mg and negative difference effect(NDE) were suppressed. Thus, the corrosion resistance of AZ31 Mgalloy in SBF was significantly improved.

关键词： AZ31 Mg alloy D-Fructose SBF EIS Hydroxyapatite

Effect of glycine addition on the in-vitro corrosion behavior of AZ31 magnesium alloy in Hank’s solution

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第22期81卷 97-107页

作者： Durga Bhakta Pokharel Liping Wu Junhua Dong Amar Prasad Yadav dhruba babu subedi Madhusudan Dhakal Lin Zha Xin Mu Aniefiok Joseph Umoh Wei Ke Shenyang National Laboratory for Materials Science(SYNL) Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Material Science and Engineering University of Science and Technology of ChinaHefei230026China Environmental Corrosion Center Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Central Department of Chemistry Tribhuvan UniversityKirtipurNepal

This study reports on the effect of the addition of Glycine to Hank’s solution on the in-vitro corrosion behavior of AZ31 magnesium(Mg)alloy at 37℃and a pH of 7.4 studied by using potentiodynamic polarization(PDP),hydrogen collecting techniques and electrochemical impedance spectroscopy(EIS)in combination with surface characterization techniques such as optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy analysis(XPS).The results reveal that adsorption of glycine initially subdues the dissolution of AZ31 Mg alloy while in long run it enhances the dissolution of the alloy due to the commencement of the chelation effect of glycine with Ca^(2+) released from hydroxyapatite.The chelation of glycine with Ca^(2+) induces the formation of cracks in the surface film which further promotes the dissolution of AZ31 Mg alloy thereby forming a porous corrosion products layer on the surface of the alloy.As a result,both the continuous dissolution of AZ31 magnesium alloy and the hydrogen evolution rate(HER)are enhanced with increasing the immersion time in Hank’s solution.

关键词： AZ31 Mg alloy Glycine Hank’s solution EIS Chelating effect

Photo-catalytic decolourisation of toxic dye with N-doped titania:A case study with Acid Blue 25

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2013年第5期25卷 1034-1043页

作者： dhruba Chakrabortty Susmita Sen Gupta Department of Chemistry B N CollegeDhubriAssamIndia

Dyes are one of the hazardous water pollutants.Toxic Acid Blue 25,an anthraquinonic dye,has been decolourised by photo-catalysing it with nitrogen doped titania in aqueous medium.The photo catalyst was prepared from 15% TiCl 3 and 25% aqueous NH 3 solution as precursor.XRD and TEM revealed the formation of well crystalline anatase phase having particle size in the nano-range.BET surface area of the sample was higher than that of pure anatase TiO 2.DRS showed higher absorption of radiation in visible range compared to pure anatase TiO 2.XPS revealed the presence of nitrogen in N-Ti-O environment.The experimental parameters,namely,photocatalyst dose,initial dye concentration as well as solution pH influence the decolourisation process.At pH 3.0,the N-TiO 2 could decolourise almost 100% Acid Blue 25 within one hour.The influence of N-TiO 2 dose,initial concentration of Acid Blue 25 and solution pH on adsorption-desorption equilibrium is also studied.The adsorption process follows Lagergren first order kinetic

关键词： Acid Blue 25 decolourisation nitrogen-doped titania photocatalysis

Densification behavior of yttria-stabilized zirconia powders for solid oxide fuel cell electrolytes

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2018年第4期7卷 325-335页

作者： dhruba PANTHI Nader HEDAYAT Yanhai DU College of Aeronautics and Engineering Kent State University Department of Engineering Technology Kent State University at Tuscarawas

Yttria-stabilized zirconia(YSZ) is the most common electrolyte material for solid oxide fuel cells. Herein, we conducted a comparative study on the densification behavior of three different kinds of commercial 8 mol% YSZ powders:(i) TZ-8Y(Tosoh, Japan),(ii) MELox 8Y(MEL Chemicals, UK), and(iii) YSZ-HT(Huatsing Power, China). The comparison was made on both the selfsupporting pellets and thin-film electrolytes coated onto a NiO–YSZ anode support. For the pellets, MELox 8Y showed the highest densification at lower sintering temperatures with 93% and 96% of the theoretical density at 1250 and 1300 ℃, respectively. Although YSZ-HT showed a higher sintering rate than TZ-8Y, a sintering temperature of 1350 ℃ was required for both the powders to reach 95% of the theoretical density. For the thin-film electrolytes, on the other hand, YSZ-HT showed the highest sintering rate with a dense microstructure at a co-sintering temperature of 1250 ℃. Our results indicate that besides the average particle size, other factors such as particle size distribution and post-processing play a significant role in determining the sintering rate and densification behavior of the YSZ powders. Additionally, a close match in the sintering shrinkage of the electrolyte and anode support is important for facilitating the densification of the thin-film electrolytes.

关键词： yttria-stabilized zirconia (YSZ) SOFC electrolyte densification shrinkage co-sintering

Kinematics of faults in Bengal Basin:Constraints from GPS measurements

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2020年第4期11卷 242-251页

作者： Mallika Mullick dhruba Mukhopadhyay Raman Centre for Applied and Interdisciplinary Sciences 16AJheel RoadKolkata700075India

The crustal deformation of Bengal Basin is constrained by motion on faults within the basin and those along the basin boundaries on all sides except the southern margin.Eocene Hinge Zone(EHZ),the most prominent structure within Bengal Basin,running through Kolkata-Ranaghat-Mymensingh,shows present day reactivation by hosting 8 earthquakes of magnitude 5.3 to 7.2 on or near its vicinity since 1906.Analysis of GPS derived velocities of stations around the hinge belt reveals a change in crustal kinematics across the belt.The predicted fault model that best fits the observed GPS station velocities on the surface shows that EHZ is a low angle east dipping fault which is locked to a depth of 10 km below the alluvium cover with a maximum slip rate deficit of 1.6±0.7 mm/yr in its northern part at a shallow depth from surface while the deficit in the southern part of EHZ is 1.0±0.6 mm/yr.The Garh-Moyna Khandaghosh fault running almost parallel to the western basin-shield margin does not show significant slip rate deficit.The basin-bounding faults are more active than the faults within and therefore they are greater sources of seismic hazard in the basin.The model results reveal that the Sylhet trough region in the northeastern corner is most vulnerable to future earthquakes as it undergoes deformation due to a maximum slip rate deficit of 9.5±2.4 mm/yr on the shallowly dipping locked megathrust along the eastern margin of the basin plus that of 7.4±2.6 mm/yr on the over thrusting Dapsi thrust and Dauki fault in the north.

关键词： Bengal basin Active faults GPS Slip rate deficit Coupling fraction

Quantitative analysis of the Nepal earthquake on 25 April, 2015 in the perspective of future earthquake hazard

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2017年第2期8卷 77-83页

作者： Mallika Mullick dhruba Mukhopadhyay Raman Centre for Applied and Interdisciplinary Sciences 16A Jheel Road Kolkata 700075 India

The earthquake that occurred in Nepal on 25 April, 2015 was followed by about 256 aftershocks which continued for another 20-25 days. The Coulomb stress change due to the main shock has been estimated at depths 10 km, 15 km and 22 km which justify the occurrence of about 218 aftershocks of magnitudes 4 to 5 mostly at 10 km depth and the rest of magnitudes 5 to 7.3 mostly at 15-30 km depth. The western, southern and northern fringes of the fault plane that slipped on 25 April, 2015 show a high value of positive Coulomb stress change estimated at the above mentioned depths and yet these parts of the fault remained devoid of any aftershock epicentre and therefore must be treated as seats for possible future events. Co-seismic displacement of 5 GPS stations located in Nepal after the devastating earthquake of MwZ8 on 25 April, 2015 and its largest aftershock of MwZ3 on 12 May, 2015 have been separately estimated and analysed.

关键词： Nepal Himalaya Aftershock Positive Coulomb stress change Co-seismic displacement Future earthquake

Tectonic control on the drainage system in a piedmont region in tectonically active eastern Himalayas

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2012年第1期6卷 29-38页

作者： Chandreyee GOSWAMI dhruba MUKHOPADHYAY Bikash Chandra PODDAR Asutosh College Saltlake CityKolkata 700026India Raman Center for Applied and Interdisciplinary Sciences Saltlake CityKolkata 700075India BE 267 Saltlake CityKolkata 700064India

The impact ofneotectonic activity on drainage system has been studied in a large alluvial fan in the eastern Himalayan piedmont area between the Mal River and the Murti River. Two distinct E-W lineaments passing through this area had been identified by Nakata （1972, 1989） as active faults. The northern lineament manifested as Matiali scarp and the southern one manifested as Chalsa scarp represent the ramp anticlines over two blind faults, probably the Main Boundary Thrust （MBT） and the Himalayan Frontal Thrust （HFT）, respectively. The fan surface is folded into two antiforms with a synform in between. These folds are interpreted as fault propagation folds over the two north dipping blind thrusts. Two lineaments trending NNE-SSW and nearly N-S, respec- tively, are identified, and parts of present day courses of the Murti and Neora Rivers follow them. These lineaments are named as Murti and Neora lineaments and are interpreted to represent a conjugate set of normal faults. The rivers have changed their courses by the influence of these normal faults along the Murti and Neora lineaments and their profiles show knick points where they cross E-W thrusts. The overall drainage pattern is changed from radial pattern in north of the Matiali scarp to a subparallel one in south due to these conjugate normal faults. The interfluve area between these two rivers is uplifted as a result of vertical movements on the above mentioned faults. Four major terraces and some minor terraces are present along the major river valleys and these are formed due to episodic upliftment of the ground and subsequent down- cutting of the rivers. The uppermost terrace shows a northerly slope north of the Chalsa scarp as a result of folding mentioned above. But rivers on this terrace form incised channels keeping their flow southerly suggestingthat they are antecedent to the folding and their downcutting kept pace with the tectonism.

关键词： alluvial fan drainage pattern thrust normalfault active tectonic