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magnesium nanocomposites:An overview on time-dependent plastic(creep) deformation

Defence Technology（防务技术） 2019年第2期15卷 123-131页

作者： m.Haghshenas m.gupta Department of mechanical Engineering University of North Dakota Department of mechanical Engineering National University of Singapore

magnesium(mg) nanocomposites are created when nano-size particles are embedded into the mg(or mg alloy) matrix. The mg nanocomposites, cited as high-strength energy-saving materials of future, are a group of emerging materials with excellent combination of strength and ductility and superior specific strength property(strength-to-weight ratio). Having said this, mg nanocomposites are considered as promising replacement for other structural alloys(i.e. aluminum and titanium) wherever low density and high strength are required, i.e. transportation, aerospace, defense, etc. To be able to apply this group of materials for real components, different failure mechanisms at ambient and elevated temperatures under static and dynamic loading condition must be well documented. Compared with other metals and alloys,rate-dependent plastic deformation(creep), at ambient and elevated temperatures, of these novel materials is not yet well studied which seems a tangible lack of knowledge. This is required since the materials in service are often exposed to medium and elevated temperatures and/or static loads for long duration of time and this encourages creep failure on them. To this end, the information and the controlling mechanisms on time/temperature-dependent response of the material need to be developed to be able to predict the response of the mg nanocomposites where the materials are under creep conditions. This paper aims at providing an overview on(i) creep-resistant mg alloys(as matrix) and their chemical compositions, and(ii) responses of the mg nanocomposites at different creep conditions(time and temperature). The controlling mechanisms contributing to the strength and ductility of the mg nanocomposites due to the presence of the nanoparticles have been reviewed briefly in the present article. In this paper both traditional(uniaxial) and depth-sensing indentation creep of mg nanocomposites are reviewed. Also, some fundamental questions and possible explanations have be

关键词： mg nanocomposite Creep Strength Reinforcement Nanoparticles

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Scaling of residual displacements in terms of elastic and inelastic spectral displacements for existing SDOF systems

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Earthquake Engineering and Engineering Vibration 2020年第1期19卷 71-85页

作者： m.G.Harikrishnan Vinay K.gupta Department of Civil Engineering Indian Institute of Technology Kanpur

Structures undergoing inelastic displacements during earthquake ground motions are known to sustain some amount of residual displacements, which may make them unusable or unsafe. In this study an attempt is made to estimate residual displacements for elastic-perfectly-plastic single-degree-of-freedom oscillators with a given lateral strength ratio. It is observed in the case of a class of ground motions that there are no trends in the dependence of residual displacement on the temporal features of the ground motion, and thus any estimation of residual displacements should be carried out only in the statistical sense. Statistical estimation of residual displacement spectrum via normalization with respect to inelastic or elastic spectral displacements is considered, and it is found that normalization with respect to inelastic spectral displacements is preferable. Expressions for residual displacement spectra are proposed for both types of normalizations and for the givenlateral-strength-ratio type oscillators.

关键词： residual displacement spectrum lateral strength ratio elastic-perfectly-plastic oscillator inelastic displacement spectrum elastic displacement spectrum horizontal ground motions

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Tourmaline from the Archean *** gold deposit,Chitradurga greenstone belt,Dharwar craton(India):Implications for the gold metallogeny

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Geoscience Frontiers 2014年第6期5卷 877-892页

作者： Susmita gupta m.Jayananda Fareeduddin Geological Survey of India (GSI) NERGuwahatiAssam 781 005India Department of Geology Centre of Advanced StudiesUniversity of DelhiDelhi 110 007India Geochronology and Isotope Geology Division Central HeadquarterGSIKolkata 700 016India

Tourmaline occurs as a minor but important mineral in the alteration zc,ne of the Archean orogenic gold deposit of Guddadarangavanahalli （***） in the Chitradurga greenst^ne belt of the western Dharwar craton, southern India. It occurs in the distal alteration halo of the *** golcl deposit as （a） clusters of very fine grained aggregates which form a minor constituent in the natrix of the altered metabasalt （AmB tourmaline） and （b） in quartz-carbonate veins （vein tourmaline）. ~[＇he vein tourmaline, based upon the association of specific carbonate minerals, is further grouped as （i） albite-tourmaline-ankerite-quartz veins （vein-1 tourmaline） and （ii） albite-tourmaline-calcite-quartz veins （vein-2 tourmaline）. Both the AmB tourmaline and the vein tourmalines （vein-I and vein-2） belong to the alkali group and are clas- sified under schorl-dravite series. Tourmalines occurring in the veins are zoned while the AmB tour- malines are unzoned. mineral chemistry and discrimination diagrams 1eveal that cores and rims of the vein tourmalines are distinctly different. Core composition of the ve：n tourmalines is similar to the composition of the AmB tourmaline. The formation of the AmB tourmaline and cores of the vein tour- malines are proposed to be related to the regional D1 deformational event associated with the emplacement of the adjoining ca. 2.61 Ga Chitradurga granite whilst rims of the vein tourmalines vis-a- vis gold mineralization is spatially linked to the juvenile magmatic accretion （2.56-2.50 Ga） east of the studied area in the western part of the eastern Dharwar craton.

关键词： Tourmaline G.R.HalIi Orogenic gold deposit Dharwar craton Archean

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Spatial Variability of mass movements in the Satluj Valley,Himachal Pradesh during 1990～2006

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Journal of mountain Science 2008年第1期5卷 38-51页

作者： Vikram gupta m.P.SAH Wadia Institute of Himalayan Geology Dehra Dun-24 8 001 (Uttarakhand)

Satluj Valley is known to have a history of landslides and related mass movement activities since the geological times. Geological and geomorphological settings combined with anthropogenic activities constitute a propensity towards slope failure. During the last two decades,the area witnessed substantial increase in athropogenic pressure,mainly due to the exploitation of hydropower potential,changing landuse pattern and population growth. In addition,a shift of the climatic patterns in the form of larger area falling under the influence of rains was observed. These natural as well as anthropogenic changes in the area have resulted in increased spatial coverage of landslide in the area. This paper documents these changes during 1990～2006.

关键词： Landslides mass movement Satluj Valley Himachal Pradesh India

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Population structure analysis and determination of neurotoxin content in a set of grass pea (Lathyrus sativus L.) accessions of Bangladesh origin

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The Crop Journal 2018年第4期6卷 435-442页

作者： Priyanka gupta Sripada m. Udupa Debjyoti Sen gupta Jitendra Kumar Shiv Kumar International Center for Agricultural Research in the Dry Areas Rabat Institute Rabat Morocco Department of Plant Sciences North Dakota State University Fargo ND 58105 USA ICAR-Indian Institute of Pulses Research Kanpur Uttar Pradesh 208024 India

Grass pea(Lathyrus sativus L.) is a crop that is considered one of the more resilient to climate change. With protein-rich seeds and leaves, it has strong potential as human food as well as animal feed and fodder. However, genetic improvement in this crop remains stagnant owing to the poor characterization of its genetic resources. In this study, we characterized 118 accessions of grass pea with 18 EST-SSR markers. A total of 118 accessions, 101 of L. sativus(100 cultivated accessions from Bangladesh and one wild accession) and 17 wild accessions of other Lathyrus species, were used. A total of 67 alleles were detected, with an average of 3.72 alleles per locus and average polymorphism information content of 0.52. A dissimilarity matrix was formed and hierarchical cluster analysis performed using the UPGmA method grouped genotypes into four main clusters. Cluster analysis based on the genetic dissimilarity revealed a clear grouping of the 100 cultivated and 18 wild accessions into four main groups. Group I consisted of 20 accessions with high β-N-oxalyl-L-α,β-diaminopropionic acid(β-ODAP) concentration. Of these 20 accessions, 17 were wild accessions. Only one wild accession(L. cicera) was clustered in group II, which contained 35 accessions. most of the group II accessions contained low β-ODAP. Group III was represented by 34 accessions, many of them with high β-ODAP. Group IV consisted of 29 accessions, a few of which had very high β-ODAP concentrations. Analysis of molecular variance of the microsatellite data showed significantly higher values of molecular variance between(83%) than within(17%) populations. These characterized accessions will be useful in grass pea breeding programs.

关键词： Lathyrus Population structure EST-SSRβ-ODAP Genetic diversity

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Development and Characterization of Sol-gel Derived Al Doped ZnO/p-Si Photodiode

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Journal of materials Science & Technology 2010年第3期26卷 223-227页

作者： Babita gupta Anubha Jain R.m.mehra Department of Electronic Science University of Delhi South Campus

The effect of Al doping on the J-V characteristics sol-gel derived of ZnO/p-Si photodiodes was *** resistivity of Si was 0.1Ω·*** films annealed at 500℃ were of the best *** investigate the spectral response of the photodiodes,the J-V characteristics were measured under different monochromatic lights at wavelength 420,530,570 and 630 *** diodes exhibit strong responsivity in the blue region at 420 *** responsivity is 0.22 A/W for Al doped （0.8 wt pct） photodiode,whereas for the undoped photodiode,it was much *** estimate of the responsivity as a function of wavelength has been made in terms of the width of depletion region of photodiodes.

关键词： Sol-gel Al doping Photodiode J-V characteristics Responsivity

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matSciBERT:A materials domain language model for text mining and information extraction

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npj Computational materials 2022年第1期8卷 940-950页

作者： Tanishq gupta mohd Zaki N.m.Anoop Krishnan mausam Department of mathematics Indian Institute of Technology DelhiHauz KhasNew Delhi110016India Department of Civil Engineering Indian Institute of Technology DelhiHauz KhasNew Delhi110016India School of Artificial Intelligence Indian Institute of Technology DelhiHauz KhasNew Delhi110016India Department of Computer Science and Engineering Indian Institute of Technology DelhiHauz KhasNew Delhi110016India

A large amount of materials science knowledge is generated and stored as text published in peer-reviewed scientific *** recent developments in natural language processing,such as Bidirectional Encoder Representations from Transformers(BERT)models,provide promising information extraction tools,these models may yield suboptimal results when applied on materials domain since they are not trained in materials science specific notations and ***,we present a materials-aware language model,namely,matSciBERT,trained on a large corpus of peer-reviewed materials science *** show that matSciBERT outperforms SciBERT,a language model trained on science corpus,and establish state-of-the-art results on three downstream tasks,named entity recognition,relation classification,and abstract *** make the pre-trained weights of matSciBERT publicly accessible for accelerated materials discovery and information extraction from materials science texts.

关键词： such text weights

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Revisiting novel symmetries in coupled N=2 supersymmetric quantum systems:examples and supervariable approach

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Communications in Theoretical Physics 2020年第10期72卷 103-112页

作者： Aditi Pradeep Anjali S Binu m Nair Saurabh gupta Department of Physics and Astronomy University of British ColumbiaVancouver Campus325-6224 Agricultural RoadVancouverBC V6T 1Z1Canada Department of Physics National Institute of Technology Calicut

We revisit the novel symmetries in N=2 supersymmetric quantum mechanical models by considering specific examples of coupled ***,we extend our analysis to a general case and list out all the novel *** each case,we show the existence of two sets of discrete symmetries that correspond to the Hodge duality operator of differential ***,we are able to provide a proof of the conjecture which points out the existence of more than one set of discrete symmetry transformations corresponding to the Hodge duality ***,we derive on-shell nilpotent symmetries for a generalized superpotential within the framework of supervariable approach.

关键词： N=2 SUSY quantum mechanical system continuous and discrete symmetries de Rham cohomological operators (anti-)chiral supervariable approach SUSY invariant restrictions

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Optical Photometric Observations of 7-Ray Loud Blazars

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Chinese Journal of Astronomy and Astrophysics 2004年第2期4卷 133-142页

作者： Jun-HuiFan O.m.Kurtanidze m.G.Nikolashvili A.C.gupta CenterforAstrophysics GuangzhouUniversityGuangzhou510400 AbstumaniObservatory 383762AbstumaniRepublicofGeorgia Harish-ChandraResearchInstitute ChhatnagRoadJhunsiAllahabad-211019India

We report results of our optical photometric observations of ten gamma-ray loud blazers, namely: 0219+428 (3C66A), PKS 0420-014 (OA 129), S5 0716+714, 0754+100 (OI 090.4), 0827+243 (OJ248), 1652+398 (mrk 501), 2200+420 (BL Lacertae), 2230+114 (CTA 102), 2251+158 (3C 454.3) and 2344+514. The observations were carried out in September-October, 2000 using the 70 cm optical telescope at Abstumani Observatory, Georgia. We found intra-day variations in 0420-014, S5 0716+714, BL Lacertae and CTA 102. A variation of 0.3 magnitude over a time scale of about 3 hours was observed in the R passband in BL Lacertae on JD 2451827. We did not detect any variation in 3C 66A, mrk 501, or 3C 454.3 during our observations. Nor did we detect any clear evidence of variation in 1ES 2344+514 during our two weeks' observing run of the TeV gamma-ray source.

关键词： galaxies: active - Blazars: individual: PKS 0219+428 (3C 66A) PKS 0420-014 (OA129) S5 0716+714 0754+100 (OI090.4) 0827+243 (OJ248) 1652+398 (mrk 501) 2200+420 (BL Lacertae) 2230+114 (CTA102) 2251+158 (3C 454.3) and 1ES 2344+514 - galax

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Bibliographic survey and comprehensive review on mechanical and durability properties of microorganism based self-healing concrete

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Frontiers of Structural and Civil Engineering 2024年第9期18卷 1445-1465页

作者： md marghoobul HAQUE Kunal m.SHELOTE Namrata SINGH Supratic gupta Department of Civil Engineering Indian Institute of Technology DelhiNew Delhi 110016India

Concrete is the most widely utilized material for construction purposes,second only to water,in the ever-increasing need for construction *** is a brittle material and possesses a high risk of crack formation and consequent ***,which allows chemicals to enter and can cause concrete structures to lose their physico-mechanical and durability *** and rehabilitating concrete structures involves high costs and leads to various repair methods including coating,adhesives,polymers,supplementary cementitious materials(SCms),and *** of the latest technologies is the use of microorganisms in *** added microorganisms lead to calcite precipitation and thereby heal the cracks *** study presents a comprehensive literature survey on bacteria-included concrete,before which a bibliographic survey is performed using VOSViewer *** addition to regular bacterial concrete,this study focuses on also using SCms and fibers in bacterial concrete.A detailed literature review with data representation for various mechanical properties including compressive strength(CS),split tensile strength(SS),and flexure strength(FS),along with durability properties including carbonation,water absorption,resistance against chloride ion penetration,gas permeation,and resistance against cyclic freeze-and-thaw is presented.A study on the use of X-ray computed tomography(XCT)in bacterial concrete is highlighted,and the scope for future research,along with identification of the research gap,is presented.

关键词： bacterial concrete bibliographic survey biomineralization carbonation fibers

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