检索结果-南通市图书馆

Effect of interlayer addition on microstructure and mechanical properties of NiTi/stainless steel joint by electron beam welding

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2期61卷 16-24页

作者： h.Niu h.C.jiang m.j.Zhao L.j.Rong CAS Key Laboratory of Nuclear materials and Safety Assessment Institute of Metal ResearchChinese Academy of ScienceShenyang110016China School of materials Science and Engineering University of Science and Technology of ChinaHefei230026China

NiTi/Stainless Steel(SS) sheets have been welded via a vacuum electron beam welding process, with three methods(offsetting electron beam to SS side without interlayer, adding Ni interlayer and adding Fe Ni interlayer), to promote mechanical properties of the Ni Ti/SS joints. The joints with different interlayers are all fractured in the weld zone near the Ni Ti side, which is attributed to the enrichment of intermetallic compounds including Fe2 Ti and Ni3 Ti. The fracture mechanisms of different joints are strongly dependent on the types of interlayers, and the joints without interlayer, adding Ni interlayer and adding Fe Ni interlayer exhibit cleavage fracture, intergranular fracture and mixed fracture composed of cleavage and tearing ridge, respectively. Compared with the brittle laves phase Fe2 Ti, Ni3 Ti phase can exhibit certain plasticity, block the crack propagation and change the direction of crack propagation. The composite structure of Ni3 Ti and Fe2 Ti will be formed when the Fe Ni alloy is taken as the interlayer, which provides the joint excellent mechanical properties, with rupture strength of 343 mPa.

关键词： NiTi Stainless steel Electron beam welding Interlayer mechanical property

A Plant SmALL RNA-BINDING PROTEIN 1 Family mediates Cell-to-Cell Trafficking of RNAi Signals

在线全文

学校读者我要写书评

暂无评论

molecular Plant 2020年第2期13卷 321-335页

作者： Yan Yan Byung-Kook ham Yee hang Chong Shyi-Dong Yeh William j.Lucas Department of Plant Biology College of Biological SciencesUniversity of CaliforniaDavisCA 95616USA Department of Plant Pathology National Chung-Hsing UniversityTaichung Present address:Global Institute for Food Security University of SaskatchewanSaskatoonSK S7N 4J8Canada Present address:Department of Biology University of Saskatchewan112 Science PlaceSaskatoonSK S7N 5E2Canada

In plants,RNA interference(RNAi)plays a pivotal role in growth and development,and responses to environmental inputs,including pathogen *** intercellular and systemic trafficking of small interfering RNA(siRNA)/microRNA(miRNA)is a central component in this regulatory ***,little is known with regards to the molecular agents involved in the movement of these si/*** address this situation,we employed a biochemical approach to identify and characterize a conserved SmALL RNA-BINDING PROTEIN 1(SRBP1)family that mediates non-cell-autonomous small RNA(sRNA)*** Arabidopsis,AtSRBP1 is a glycine-rich(GR)RNA-binding protein,also known as AtGRP7,which we show binds single-stranded siRNA.A viral vector,Zucchini yellow mosaic virus(ZYmV),was employed to functionally characterized the AtSRBP1-4(AtGRP7/2/4/8)RNA recognition motif and GR ***-based studies revealed the GR domain as being necessary and sufficient for SRBP1 cell-to-cell *** together,our findings provide a foundation for future research into the mechanism and function of mobile sRNA signaling agents in plants.

关键词： RNAi small RNA-binding protein family small RNA movement non-cell-autonomous protein glycinerich protein

Biological transformation,kinetics and dose-response assessments of bound musk ketone hemoglobin adducts in rainbow trout as biomarkers of environmental exposure

维普期刊数据库评论

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 Environmental Sciences 2008年第7期20卷 878-884页

作者： m A mottaleb j h Zimmerman T W moy Department of Chemistry and Biochemistry Baylor UniversityP.O.Box 97348WacoTX 76798USA. U.S.Environmental Protection Agency National Exposure Research LaboratoryEnvironmental Sciences Division944 East Harmon AveLas VegasNV 89119USA

Low levels (ng/g) of musk ketone (mK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other ***,aquatic organisms can be continuously exposed to *** this study,kinetics and dose-response assessments of 2-amino-mK (AmK) metabolite,bound to cysteine-hemoglobin (hb) in rainbow trout,formed by enzymatic nitro-reduction of mK have been *** were exposed to a single exposure of 0.010,0.030,0.10,and 0.30 mg mK/g ***...

关键词： biotransformation kinetics hemoglobin adducts dose-response nitro musks biomarker fish

Generation of linear and nonlinear waves in numerical wave tank using clustering technique-volume of fluid method

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English edition) 2012年第9期33卷 1179-1190页

作者： h.SAGhI m.j.KETABDARI S.BOOShI Department of Civil Engineering Ferdowsi UniversityMashhad 91779-4897Iran Faculty of marine Technology Amirkabir University of TechnologyTehran 15875-4413Iran

A two-dimensional （2D） numerical model is developed for the wave sim- ulation and propagation in a wave flume. The fluid flow is assumed to be viscous and incompressible, and the Navier-Stokes and continuity equations are used as the governing equations. The standard k-e model is used to model the turbulent flow. The Navier- Stokes equations are discretized using the staggered grid finite difference method and solved by the simplified marker and cell （SmAC） method. Waves are generated and propagated using a piston type wave maker. An open boundary condition is used at the end of the numerical flume. Some standard tests, such as the lid-driven cavity, the constant unidirectional velocity field, the shearing flow, and the dam-break on the dry bed, are performed to valid the model. To demonstrate the capability and accuracy of the present method, the results of generated waves are compared with available wave theories. Finally, the clustering technique （CT） is used for the mesh generation, and the best condition is suggested.

关键词： numerical wave tank free surface simulation Navier-Stokes equation stag-gered grid clustering technique (CT) wave generation

Spatial Prediction of Soil Aggregate Stability and Aggregate-Associated Organic Carbon Content at the Catchment Scale Using Geostatistical Techniques

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2011年第3期21卷 389-399页

作者： j.mOhammADI m.h.mOTAGhIAN Department of Soil Science Agriculture CollegeShahrekord University

The association of organic carbon with secondary particles （aggregates） results in its storage and retention in soil. A study was carried out at a catchment covering about 92 km2 to predict spatial variability of soil water-stable aggregates （WSA）, mean weight diameter （mWD） of aggregates and organic carbon （OC） content in macro.- （〉 2 mm）, meso- （1-2 mm）, and micro-aggregate （〈 1 mm） fractions, using geostatistical methods. One hundred and eleven soil samples were eSlleeted at the 0 10cm depth and fractionated into macro-, meso-, and mlcro-aggregates by wet sieving. The OC content was determined for each fraction. A greater percentage of water-stable aggregates was found for micro-aggregates, followed by meso-aggregates. Aggregate OC content was greatest in meso-aggregates （9 g kg-1）, followed by micro-aggregates （7 g kg-1）, while the least OC content was found in macro-aggregates （3 g kg-1）. Although a significant effect （P = 0.000） of aggregate size on aggregate OC content was found, however, our findings did not support the model of aggregate hierarchy. Land use had a significant effect （P = 0.073） on aggregate OC content. The coefficients of variation （CVs） for OC contents associated with each aggregate fraction indicated macro-aggregates as the most variable （CV = 71%）. Among the aggregate fractions, the micro-aggregate fraction had a lower CV value of 27%. macro-aggregates to 84% for micro-aggregates. Geostatistical analysis differences in their spatial patterns in both magnitude and space at variance for most aggregate-associated properties was lower than 45%. The mean content of WSA ranged from 15% for showed that the measured soil variables exhibited each aggregate size fraction. The relative nugget The range value for the variogram of water-stable aggregates was almost similar （about 3 km） for the three studied aggregate size classes. The range value for the variogram of aggregate-associated OC contents ranged from about 3 km for macro-aggregates to about

关键词： kriging organic matter variogram water-stable aggregates

Segregation of particulate solids: Experiments and DEm simulations

在线全文

学校读者我要写书评

暂无评论

Particuology 2014年第1期12卷 25-32页

作者： m.Combarros h.j.Feise h.Zetzener A.Kwade Institut für Partikeltechnik TU BraunschweigBraunschweig Germany BASF SE Ludwigshafen Germany

Segregation of granular materials is a complex phenomenon, difficult to measure quantitatively and to predict. Discrete element method （DEm） can be a useful tool to predict segregation effects and to support the industrial design. In this context, a very challenging idea is the characterization of the granular solids to provide the key parameters needed for a successful DEm simulation of segregation processes. Rolling friction, sliding friction and the coefficient of restitution are the critical parameters to be studied. These microscopic simulation parameters are calibrated by comparing the macroscopic behavior of granular matter in standard bulk experiments, which have the advantage of being highly repeatable and reliable. An experimental method is presented to characterize free surface segregation. The effects of different particle properties, particularly, shape and size, on segregation of cohesionless materials were investi- gated. From the experiments, particle size demonstrated a stronger effect on segregation than particle shape. Finally, the corresponding DEm simulations of the segregation experiments were presented. The parameters obtained by calibration were validated by the comparison of the modeled segregation behav- ior with the experimental results. Thus, calibrated DEm simulations are capable of predicting segregation effects.

关键词： Bulk solidsParticle shapeSegregationDEmDiscrete element methodSilo

Nonlinear elastic constitutive relations of residually stressed composites with stiff curved fibres

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English edition) 2022年第10期43卷 1515-1530页

作者： m.h.B.m.Shariff j.merodio R.Bustamante Department of mathematics Khalifa University of Science and TechnologyAbu Dhabi127788United Arab Emirates Departamento de matemática Aplicada a las TIC ETS de Ingeniería de Sistemas InformaticosUniversidad Politecnica de MadridMadrid28031Spain Departamento de Ingeniería mecánica Universidad de ChileBeauchef 851Santiago CentroSantiago8370448Chile

mechanical models of residually stressed fibre-reinforced solids,which do not resist bending,have been developed in the ***,in some residually stressed fibre-reinforced elastic solids,resistance to fibre bending is significant,and the mechanical behavior of such solids should be ***,in this paper,we model the mechanical aspect of residually stressed elastic solids with bending stiffness due to fibre curvature,which up to the authors’knowledge has not been mechanically modeled in the *** proposed constitutive equation involves a nonsymmetric stress and a couple-stress *** invariants are used in the constitutive equation,where each spectral invariant has an intelligible physical meaning,and hence they are useful in experiment and analysis.A prototype strain energy function is ***,we use this prototype to give results for some cylindrical boundary value problems.

关键词： fibre-reinforced solid residual stress bending stiffness spectral invariant second gradient finite elasticity

Photo-induced Synthesis and Characterization of Poly(methyl methacrylate) Grafted Sodium Salt of Partially Carboxymethylated Guar Gum

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Polymer Science 2014年第12期32卷 1690-1703页

作者： j.h.Trivedi m.D.Thaker h.C.Trivedi P.G. Department of Chemistry Sardar Patel University

Photo-induced graft copolymerization of methyl methacrylate（mmA） onto sodium salt of partially carboxymethylated guar gum（Na-PCmGG, DS = 0.291） was carried out in an aqueous medium using ceric ammonium nitrate（CAN） as photoinitiator to synthesize a novel graft copolymer, Na-PCmGG-g-PmmA, which may find its potential application as a metal adsorbent. The influences of synthesis variables such as concentrations of photoinitiator（CAN）, nitric acid and monomer（mmA） as well as reaction time, temperature and amount of substrate on the grafting yields were studied and the reaction conditions for optimum photo-grafting were evaluated. At optimum concentration, the maximum values of the grafting yields achieved were G = 271.61% and GE = 63.89%. The experimental results were found to be in very good agreement with the proposed kinetic scheme. The photo-graft copolymerization of mmA onto Na-PCmGG（ DS = 0.291） was also carried out in the presence and absence of ultraviolet radiation for studying the efficiency of the photoinitiator. The influence of carboxymethyl groups introduced onto the guar gum molecules with regard to its behavior towards ultra-violet radiation induced grafting with mmA was also investigated. Photo-grafting process was confirmed and the products were characterized with the help of the spectroscopic（1h-NmR and FTIR） and SEm techniques.

关键词： Photo-induced grafting methyl methacrylate Sodium salt of partially carboxymethylated guar gum Optimum reaction conditions Characterization.

Arctic sea-ice extent: No record minimum in 2023 or recent years

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2025年第1期18卷 52-55页

作者： Ola m.johannessen Tor I.Olaussen Nansen Scientific Society BergenNorway Nansen Environmental and Remote Sensing Center BergenNorway

Arctic sea-ice extent reaches its minimum each year in September. On 11 September 2023 the minimum was 4.969 million square kilometers(***^(2)). This was not a record low, which occurred in 2012, when the minimum was 4.175 ***^(2), 0.794 ***^(2) less than the minimum in 2023. however, the ice extent had decreased by 0.432 ***^(2) compared with 2022. Nevertheless, the summer melting in 2023 was remarkably less than expected when considering the strong heat waves in the atmosphere and ocean, with record temperatures set around the world. In general, there is a high correlation between the long-term decrease in sea-ice extent and the increasing CO_(2) in the atmosphere, where the increase of CO_(2) in recent decades explains about 80% of the decrease in sea ice in September, while the remainder is caused by natural variability.

关键词： Sea ice Arctic minimum ice Climate