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Sea Urchin Spines as a Model-System for Permeable,Light-Weight ceramics with Graceful Failure Behavior. Part I. Mechanical Behavior of Sea Urchin Spines under compression

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Journal of Bionic Engineering 2009年第4期6卷 203-213页

作者： v.Presser S.SchultheiB c.Berthold K.GNickel Institute

The spines of pencil and lance urchins Heterocentrotus mammillatus and Phyllacanthus imperialis were studied as a model of light-weight material with high impact *** complex and variable skeleton construction ('stereom') of body and spines of sea urchins consists of highly porous Mg-bearing calcium *** basically brittle material with pronounced single-crystal cleavage does not fracture by spontaneous catastrophic device failure but by graceful failure over the range of tens of millimeter of bulk compression *** was observed in bulk compression tests and blunt indentation experiments on regular,infiltrated and latex coated sea urchin spine *** characterization was carried out using X-ray computer tomography,optical and scanning electron *** behavior is interpreted to result from the hierarchic structure of sea urchin spines from the rnacroscale down to the *** derived from this study see ceramics with layered porosity as a possible biomimetic construction for appropriate applications.

关键词： sea urchin urchin spines biominmitic mechanical behavior compression calcite

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Microstructures and mechanical properties of nanocrystalline NiTi intermetallics formed by mechanosynthesis

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International Journal of Minerals,Metallurgy and Materials 2018年第1期25卷 80-87页

作者： S.Arunkumar P.Kumaravel c.velmurugan v.Senthilkumar vinayaka Mission's Kimpananda variyar Engineering college Salem 636308TamilnaduIndia Institute of Road and Transport Technology Erode 638316TamilnaduIndia National Institute of Technology Trichy 620015TamilnaduIndia

The formulation of nanocrystallinc NiTi shape memory alloys has potential effects in mechanical stimulation and medical im- plantology. The present work elucidates the effect of milling time on the product＇s structural characteristics, chemical composition, and mi- crohardness for NiTi synthesized by mechanical alloying for different milling durations. Increasing the milling duration led to the formation of a nanocrystalline NiTi intermetallic at a higher level. The formation of nanocrystalline materials was directed through cold fusion, fractur- ing, and the development of a steady state, which were influenced by the accumulation of strain energy. In the morphological study, uninter- rupted cold diffusion and fracturing were visualized using transmission electron microscopy. Particle size analysis revealed that the mean particle size was reduced to -93 μm after 20 h of milling. The mechanical strength was enhanced by the formation of a nanocrystalline in- termetallic phase at longer milling time, which was confirmed by the results of vickers hardness analyses.

关键词： nickel-titanium shape memory alloy lattice strain nano-crystalline mechanical alloying microstructural characterization

Microstructure and mechanical properties of similar and dissimilar metal gas tungsten constricted arc welds:Maraging steel to 13-8 Mo stainless steel

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Defence Technology（防务技术） 2019年第1期15卷 111-121页

作者： c.v.S.Murthy A.Gopala Krishna G.M.Reddy Defence Research and Development Laboratory Jawaharlal Nehru Technological University Defence Metallurgical Research Laboratory

Maraging steel (250) and 13-8 Mo stainless steel plates were joined by gas tungsten constricted arc welding(GTcAW) process in similar and dissimilar metal combinations using 13-8 Mo stainless steel filler wire. The similar and dissimilar metal welds made in solutionized condition were subjected to standard post weld hardening treatments direct ageing at 485 ℃, soaking for 31/2 hours followed by air cooling(ageing treatment of maraging steel) and direct ageing at 510 ℃, soaking for 4 h followed by air cooling(ageing treatment of 13-8 Mo stainless steel). The joint characterization studies include microstructure examination, microhardness survey across the weldments and transverse weld tensile *** and dissimilar metal weldments responded to both the post weld ageing treatment. After post weld aging, increase in yield strength, UTS and slight reduction in % elongation of similar and dissimilar metal were observed. The observed tensile properties were correlated with microstructure and hardness distribution across the welds.

关键词： Maraging steel(250) 13-8 Mo stainless steel Mechanical properties Microstructure

can the grains offer each other helping hands?convergent molecular mechanisms associated with domestication and crop improvement in rice and maize

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Molecular Plant 2022年第5期15卷 793-795页

作者： ravi v.Mural James c.Schnable University of Nebraska-Lincoln LincolnNEUSA

The grasses,Poaceae,are an extraordinarily ecologically success-ful clade,with more than 10000 described extant *** grasses include more than 30 domesticated grain crops,ranging from maize(Zea mays),rice(Oryza sativa),and wheat(Triticum aes-tivum),which are collectively responsible for 50%of all calories consumed by humans around the world,to minor and orphan crops such as teff(Eragrostis tef),pearl millet(Pennisetum glaucum),proso millet(Panicum milaceum),and Job's tears(coix lacryma-jobi)(Glémin and Bataillon,2009).Domestication of grain crops from their wild relatives involved a common suite of phenotypic changes,including loss of seed shattering,loss of dormancy,and increased apical dominance,which are collectively referred to as"domestication syndrome"(Glémin and Bataillon,2009).

关键词： sativa crops collective

cLUSTERING PATENTS USING NON-EXHAUSTIvE OvERLAPS

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Journal of Systems Science and Systems Engineering 2010年第2期19卷 162-181页

作者： charles v. TraPPEY Amy J.c. TraPPEY chun-Yi WU Department of Management Science National Chiao Tung University Taiwan China Department of Industrial Engineering & Management National Taipei University of Technology Taiwan China Department of lndustrial Engineering & Engineering Management National Tsing Hua University Taiwan China

Patent documents are unique external sources of information that reveal the core technology underlying new inventions. Patents also serve as a strategic data source that can be mined to discover state-of-the-art technical development and subsequently help guide R＆D investments. This research incorporates an ontology schema to extract and represent patent concepts. A clustering algorithm with non-exhaustive overlaps is proposed to overcome deficiencies with exhaustive clustering methods used in patent mining and technology discovery. The non-exhaustive clustering approach allows for the clustering of patent documents with overlapping technical findings and claims, a feature that enables the grouping of patents that define related key innovations. Legal advisors can use this approach to study potential cases of patent infringement or devise strategies to avoid litigation. The case study demonstrates the use of non-exhaustive overlaps algorithm by clustering US and Japan radio frequency identification （RFID） patents and by analyzing the legal implications of automated discovery of patent infringement.

关键词： Data mining patent analysis patent infringement non-exhaustive overlap clustering ontology schema

Static and cyclic oxidation of Nb-cr-v-W-Ta high entropy alloy in air from 600 to 1400℃

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Journal of Materials Science & Technology 2020年第3期38卷 189-196页

作者： S.K.varma Francelia Sanchez Sabastian Moncayo c.v.ra.a.a Department Metallurgical Materials and Biomaterials EngineeringThe University of Texas at El PasoEl PasoTX79968-0520USA center for Advanced Materials Research(cMR) The University of Texas at El PasoEl PasoTX79968-0520USA

An oxidation resistance study has been made on Nb-cr-v-W-Ta high entropy alloy in a range of temperature from 600 to 1400℃in *** oxidation study has been performed for either(a)12 or 24 h of heating time or(b)3 or 10℃/min heating rates to the desired oxidation *** oxidation study conducted for three and a half days has been conducted at 600,700,and 800℃using 12 h of heating *** alloy can withstand the cyclic oxidation process with only a reasonable loss of *** identification of oxides indicates crystals of W and Ta oxides in cylindrical form while Nb and cr oxides show a nodular or granular morphology at both 1000 and 1200℃while and additional of oxide of v in whisker forms at 1200℃.

关键词： High entropy alloys Nb-cr-v-W-Ta Microstructures Oxidation

The influence of monomer concentration on the optical properties of electrochemically synthesized polypyrrole thin films

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Journal of Semiconductors 2013年第10期34卷 13-18页

作者： J.v.Thombare M.c.rath S.H.Han v.J.Fulari Holography and Material Research Laboratory Department of PhysicsShivaji UniversityKolhapur-416 004India radiation and Photochemistry Division BARCMumbaiIndia Department of chemistry Hanyang UniversitySeoulSouth Korea

Polypyrrole （PPy） thin films were deposited on stainless steel and ITO coated glass substrate at a constant deposition potential of 0.8 v versus saturated calomel electrode （ScE） by using the electrochemical polymerization method. The PPy thin films were deposited at room temperature at various monomer concentrations ranging from 0.1 M to 0.3 M pyrrole. The structural and optical properties of the polypyrrole thin films were investigated using an X-ray diffractometer （XRD）, FTIR spectroscopy, scanning electron microscopy （SEM）, and ultravioletvisible （Uv-vis） spectroscopy. The XRD results show that polypyrrole thin films have a semi crystalline structure. Higher monomer concentration results in a slight increase of crystallinity. The polypyrrole thin films deposited at higher monomer concentration exhibit high visible absorbance. The refractive indexes of the polypyrrole thin films are found to be in the range of 1 to 1.3 and vary with monomer concentration as well as wavelength. The extinction coefficient decreases slightly with monomer concentration. The electrochemically synthesized polypyrrole thin film shows optical band gap energy of 2.14 ev.

关键词： polypyrrole electrochemical polymerization method structure optical properties

Is chloroplast Movement in Tobacco Plants Influenced Systemically after Local Illumination or Burning Stress?

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Journal of Integrative Plant Biology 2008年第10期50卷 1292-1299页

作者： Jan Nau Monika Rolencov vladimíra Hlavkov Laboratory of Biophysics Department of Experimental Physics Palacky' University tr. Svobody 26 77146 Olomouc Czech Republic

chloroplast movement has been studied in many plants mainly in relation to the local light, mechanical or stress effects. Here we investigated possible systemic responses of chloroplast movement to local light or burning stress in tobacco plants （Nicotisna tabacum cv. Samsun）. chloroplast movement was measured using two independent methods： one with a SPAD 502 chlorophyll meter and another by collimated transmittance at a selected wavelength （676 nm）. A sensitive periodic movement of chloroplasts was used in high or low （2 000 or 50 μmol/m2 per s photosynthetically active radiation, respectively） cold white light with periods of 50 or 130 min. Measurements were carried out in the irradiated area, in the non-irradisted area of the same leaf or in the leaf located on the stem below the irradiated or bumed one. No significant changes in systemic chloroplast movement in non-irradiated parts of the leaf and in the non-treated leaf were detected. Our data indicate that chloroplast movement in tobacco is dependent dominantly on the intensity and spectral composition of the incident light and on the local stimulation and state of the target tissue. No systemic signal was strong enough to evoke a detectable systemic response in chloroplast movement in distant untreated tissues of tobacco plants.

关键词： buming chloroplast movement irradiance systemic response tobacco.

Unravelling the competitive effect of microstructural features on the fracture toughness and tensile properties of near beta titanium alloys

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Journal of Materials Science & Technology 2022年第2期97卷 101-112页

作者： Yang Liu Samuel c.v.Lim chen Ding Aijun Huang Matthew Weyland Department of Materials Science and Engineering Monash UniversityClaytonVIC3800Australia Monash centre for Additive Manufacturing Monash UniversityNotting HillVIC3168Australia BAOWU Special Metallurgy co.Ltd. Shanghai200940China Monash centre for Electron Microscopy Monash UniversityClaytonVIC3800Australia

The competitive effect of microstructural features including primaryα(α_(p)),secondaryα(α_(s)),grain boundaryα(α_(GB)) and β grain size on mechanical properties of a near β Ti alloy were studied with two heat treatment *** relative effect of β grain size and STA(solution treatment and ageing)processing parameters on mechanical properties were quantitatively explored by the application of Taguchi *** results were further explained via correlating microstructure with the fracture toughness and tensile *** was found that large numbers of fine as precipitates and continuous α_(s) played greater roles than other features,resulting in a high strength and very low ductility(cess *** β grain size had a negative correlation with fracture *** the samples prepared by BAScA( β anneal slow cooling and ageing)process,improved ductility and fracture toughness were obtained due to a lower density ofα;precipitates,a basket-weave structure and zigzag morphology of α_(GB).For this heat treatment,an increase in prior β grain size had an observable positive effect on fracture *** contradictory effect of β grain size on fracture toughness found in literature was for the first time *** was shown that the microstructure obtained from different processes after β solution has complex effect on mechanical *** complexity derived from the competition between microstructure features and the overall sum of their effect on fracture toughness and tensile properties.A novel table was proposed to quasi-quantitatively unravel these competitive effects.

关键词： Nearβtitanium alloys Microstructural features competitive effect Fracture toughness βgrain size effect