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Ef.ECTS Of.TREATMENT TIME ON CORROSION Of.DIf.USION-ALLOYED COATINGS Of.PURE MAGNESIUM

Acta Metallurgica Sinica(English Letters) 2007年第1期20卷 72-78页

作者： Y.P. Ma j. Li j. Zhu L. Yang Y.G. Liu Z.Y. Li f. Zhao School of.Metallurgic Engineering Xi＇an University of Architecture ＆ Technology Xi＇an 710055 China

The corrosion resistance of.pure magnesium with surf.ce alloying layer obtained by a solid dif.usion alloying technique has been analyzed. To establish the optimum treatment time, the experiments were perf.rmed at 480℃ f.r dif.erent solid dif.usion time （8, 16, and 24h）. The dif.usion interaction ef.ectiveness between Zn, Al mix powder and the sample surf.ce, depending on the treatment time f.r dif.usion at given temperatures, has an obvious inf.uence on corrosion resistance and corrosion mechanism. Corrosion properties were studied using the constant immersion test （in 3.0% NaCl solution, temperature is （28±1）℃, and time is 96h）. Optical microscopy （OM） and EDS （energy dispersive spectrum） composition analysis were used to examine the cross-sectional microstructural characteristics of.alloyed layer of.treated samples. It is shown that in comparison with the untreated samples, the treated ones possess a better corrosion resistance. The Al5Mg11Zn4 phase, which f.rmed as a continuous phase due to the dif.usion of.Al, Zn, and Mg elements and subsequent interaction on the outermost layer of.dif.usion alloying zones （especially the samples treated f.r 24h at 480℃）, was inert to the chloride solution compared with pure magnesium and acted as a corrosion barrier, and theref.re the best corrosion resistance was obtained. This protective action of.Al5Mg11Zn4 phase was f.und to change with its amount, which was controlled by the dif.usion time at given temperature. It was concluded that the continuous Al5Mg11Zn4 phase （WP-zone） of.the reacted layer in pure magnesium was benef.cial f.om the point of.view of.corrosion resistance.

关键词： pure magnesium solid dif.usion treatment time microstructure corrosion

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f.rmation and Microstructural Characterization of.Silicon-modif.ed Aluminide Coating on Nickel-based Superalloy IN738LC

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材料热处理学报 2004年第05B期25卷 657-660页

作者： f. Shahriari f. Ashraf.zadeh A. Monshi Materials engineering department Isfahan University of Technology Isfahan IranMaterials engineering department Isfahan University of Technology Isfahan IranMaterials engineering department Isfahan University of Technology Isfahan Iran

In this investigation, aluminide coatings used to protect industrial components at high temperature and corrosive environments were modif.ed with silicon addition and the microstructural f.atures and f.rmation mechanism were evaluated. The coating on the nickel-based superalloy IN738LC was carried out by a two stage process including siliconizing at f.rst and aluminizing thereaf.er. Pack cementation siliconizing perf.rmed at 950C f.r 2, 4 and 6 hours in several powder mixtures of.Si, A12O3 and NHiCl, then aluminum was dif.used into the surf.ce of.the specimens by an industrial aluminizing process. The modif.ed coatings were characterized by means of.standard metallography, scanning electron microscopy, energy dispersive spectroscopy and X-ray dif.raction methods. The results show that Si in the coatings mainly presents in the f.rm of.secondary phases including Cr3Si, Mo5Si3 and Nii6Ti6Si7, well distributed within the NiAl matrix. The advantages of.this two stage modif.ed coating is discussed.

关键词：显微结构 IN738LC 镍超级合金扩散渗碳处理生长机制

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COUPLED NUMERICAL SIMULATION ON COLD ROLLER'S TEMPERATURE f.f.D-PHASE TRANSf.RMATION - STRESS f.ELD DURING ITS QUENCHING PSOCESS

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Acta Metallurgica Sinica(English Letters) 2000年第1期13卷 254-262页

作者： j. f. Gu j. S. Pan M. j. Hu and f. f. Shen (School of.Materials Science and Engineering, Shanghai j.ao Tong University, Shanghai 200030, China)

Complicated changns occur inside the steel parts during quenching process. The abruptly changed boundary conditions make the temperature f.eld,micro - structure and stress f.eld change dramatically in very short time, and these variables take a contact interactions in the whole process. In this paper, a three dimensional non - linear mathematical model f.r queeching process has been f.unded and the numerical simulation on temperature f.eld,microstructre and stress f.eld has been *** the f.M analysis, the incremental iteration method is used to deal with such complicated nonlinear as boundary nonlinear, physical property nonlinear,transf.rmation nonlinear *** ef.ect of.stress on transf.rmation kinetics has been considered in the calculation of.microstructure. In the stress f.eld anal- ysis,a thermo- elasto - plastic model has been f.unded, which considers such f.ctors as transf.rma- tion strain,transf.rmation plastic strain, themal strain and the ef.ect of.temperature and transf.rma- tion on mechanical propertier etc. The transient temperature f.eld, microstructure distribution and stress f.eld of.the roller on any time can be displayed vividly,and the cooling curve and the changes of.stress on any position can also be given.

关键词： quenching,phase transf.rmation,temperature f.eld stress f.eld f.nite element method (f.M) numerical simulation

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Phylogenetic reconstruction of.Chirita and allies (Gesneriaceae) with taxonomic treatments

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j.urnal of.Systematics and Evolution 2011年第1期49卷 50-64页

作者： j.mes f. SMITH Department of.Biological Sciences Boise State University

Chirita D. Don, a large genus in the subf.mily Cyrtandroideae of.Gesneriaceae, has been the subj.ct of.much debate whether it is a natural group or not. In addition, the highly heterogeneous Chirita has also been very problematic with regard to delimitation and subdivision. Here we used the nrDNA internal transcribed spacer and cpDNA trnL-f.f.r molecular phylogenetic analaysis, combined with morphological data. Our results suggest that Chirita is an artif.cial, polyphyletic genus. The most important character that def.nes Chirita, the dorso-ventrally oblique and bilamellar stigma, has evolved convergently in dif.erent clades of.diandrous Cyrtandroideae. Chirita sensu stricto only includes the species of.Chirita sect. Chirita, whereas Chirita sect. Microchirita is an independent clade located at the basal node of.the phylogenetic tree. Chirita sect. Liebigia is closely related to Didymocarpus with an entire stigma unlike other species of.Chirita. The species of.Chirita sect. Gibbosaccus, Chiritopsis, Primulina, and Wentsaiboea f.rm a monophyletic group that is sister to a strongly supported clade comprising f.ur monotypic genera Paralagarosolen, Calcareoboea, Petrocodon, and Tengia. We f.rther analyzed the morphological evolution of.Chirita and identif.ed a series of.morphological synapomorphies f.r the monophyletic groups revealed herein, and thereby provide a taxonomic treatment in this study.

关键词： Chirita D. Don morphological evolution phylogenetic reconstruction polyphyly taxonomic treatment.

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Using potential distributions to explore environmental correlates of.bat species richness in southern Af.ica： Ef.ects of.model selection and taxonomy

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Current Zoology 2013年第3期59卷 279-293页

作者： M. Corrie SCHOEMAN f. P. D. (Woody) COTTERILL Peter j. TAYLOR Ara MONADj.M School of.Lif. Sciences University of KwaZulu-Natal Westville Campus Durban 4000 South Africa Af.ica Earth Observatory Network (AEON) Geoecodynamics Research Hub c/o Department of Botany and Zoology University of Stellenbosch Stellenbosch 7602 South Africa Department of.Ecology and Resource Management School of Environmental Sciences University of Venda Thohoyandou 0950 South Africa All Out Af.ica Research Unit Department of Biological Sciences University of Swaziland Private Bag 4 Kwaluseni Swaziland Mammal Research Institute Department of Zoology & Entomology University of Pretoria Private Bag 20 Hatfield 0028 Pretoria South Africa

We tested the prediction that at coarse spatial scales, variables associated with climate, energy, and productivity hy- potheses should be better predictor（s） of.bat species richness than those associated with environmental heterogeneity. Distribution ranges of.64 bat species were estimated with niche-based models inf.rmed by 3629 verif.ed museum specimens. The inf.uence of.environmental correlates on bat richness was assessed using ordinary least squares regression （OLS）, simultaneous autoregressive models （SAR）, conditional autoregressive models （CAR）, spatial eigenvector-based f.ltering models （SEVM）, and Classif.cation and Regression Trees （CART）. To test the assumption of.stationarity, Geographically Weighted Regression （GWR） was used. Bat species richness was highest in the eastern parts of.southern Af.ica, particularly in central Zimbabwe and along the western border of.Mozambique. We f.und support f.r the predictions of.both the habitat heterogeneity and climate/productivity/energy hypothe- ses, and as we expected, support varied among bat f.milies and model selection. Richness patterns and predictors of.Miniopteridae and Pteropodidae clearly dif.ered f.om those of.other bat f.milies. Altitude range was the only independent variable that was sig- nif.cant in all models and it was most of.en the best predictor of.bat richness. Standard coef.icients of.SAR and CAR models were similar to those of.OLS models, while those of.SEVM models dif.ered. Although GWR indicated that the assumption of.stationa- rity was violated, the CART analysis corroborated the f.ndings of.the curve-f.tting models. Our results identif. where additional data on current species ranges, and f.ture conservation action and ecological work are needed.

关键词： Chiroptera Macroecology Niche-based models Spatial models Species richness

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Reproductive potential of.f.eld-collected overwintering boll weevils （Coleoptera： Curculionidae） f.d on pollen in the laboratory

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Insect Science 2009年第4期16卷 321-327页

作者： S. M. Greenberg G. D. j.nes j. j. Adamczyk, j.. f. Eischen j. S. Armstrong R. j. Coleman M. Setamou Tong-Xian Liu USDA-ARS-KSARC-BIRU 2413 E. Hwy. 83 Weslaco Texas 78596 APMRU-SPA-ARS-USDA College Station Texas 77845 USDA- ARS-KSA RC-Honey Bee Research Unit Texas A&M University Kingsville Citrus Center Weslaco TX 78596 Department of.Entomology Texas AgriLife Research Texas A&M University System Weslaco Texas 78596 USA

The reproductive potential of.overwintering boll weevil, Anthonomus grandis grandis （Boheman）, f.males collected f.om pheromone traps in September, November and j.nuary, f.d f.r 1, 3, and 5 weeks on plant pollens, and then provided cotton squares, was determined in the laboratory at 27 ~ I^C, 65% RH, and a photoperiod 13 ： 11 （L ： D） h. Duration of.pollen f.eding by overwintering boll weevils did not signif.cantly inf.uence egg and f.eding punctures, or puncture ratios （egg to total punctures） f.r any of.the three months of.parent weevil collections when provided cotton squares on a daily basis. However, punctures and puncture ratios are signif.cantly dif.erent when comparing mean data between months of.boll weevil collections. When boll weevils were provided with cotton squares daily, the pre-ovipositional periods of.f.male parents captured in September, November and j.nuary were 5, 9 and 14 days, respectively. The rate of.eggs by f.males was signif.cantly lower during November and j.nuary than September. f.male parents collected in September produced a signif.cantly higher percentage of.eggs yielding adult progeny than those collected in November and j.nuary. Lif. table parameters indicated that net reproductive rate （Ro） of.boll weevil f.males collected in September was 1.2- f.ld higher than those collected in November and 10.7-f.ld higher than those collected in j.nuary. Except f.r testes size, no dif.erences in male reproductive parameters were observed during the cotton-f.ee period compared with males captured during mid-cotton （j.ne）. The number of.oocytes in the ovarioles and the number of.ooeytes containing yolk were signif.cantly lower during September, November and j.nuary compared with j.ne. The reproductive potential of.verwintering boll weevil f.males collected in dif.erent months is an important consideration in determining the success of.any control strategy.

关键词： Anthonomusgrandisgrandis overwintering boll weevil reproductive pollen

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Cadmium nanoclusters in a protein matrix： Synthesis, characterization, and application in targeted drug delivery and cellular imaging

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Nano Research 2016年第11期9卷 3229-3246页

作者： Morteza Sarparast Abolhassan Noori Hoda Ilkhani S. Zahra Bathaie Maher f. EI-Kady Lisa j. Wang Huong Pham Kristof.r L. Marsh Richard B. Kaner Mir f. Mousavi Department of.Chemistry Tarbiat Modares University Tehran 14115-175 Iran Department of.Clinical Biochemistry Faculty of Medical Sciences Tarbiat Modares University Tehran 14115-111 Iran Department of.Chemistry and Biochemistry University of California Los Angeles Los Angeles CA 90095 USA Department of.Chemistry Faculty of Science Cairo University Giza 12613 Egypt Calif.rnia NanoSystems Institute University of California Los Angeles Los Angeles CA 90095 USA

Biotemplated metal nanoclusters have garnered much attention owing to their wide range of.potential applications in biosensing, bioimaging, catalysis, and nanomedicine. Here, we report the synthesis of.stable, biocompatible, watersoluble, and highly f.uorescent bovine serum albumin-templated cadmium nanoclusters （CdNcs） through a f.cile one-pot green method. We covalently conj.gated hyaluronic acid （HA） to the CdNcs to f.rm a pH-responsive, tumor- targeting theranostic nanocarrier with a sustained release prof.le f.r doxorubicin （DOX）, a model anticancer drug. The nanocarrier showed a DOX encapsulation ef.iciency of.about 75.6%. DOX release prof.les revealed that 74% of.DOX was released at pH 5.3, while less than 26% of.DOX was released at pH 7.4 within the same 24-h period. The nanocarrier selectively recognized MCf.7 breast cancer cells expressing CD44, a cell surf.ce receptor f.r HA, whereas no such recognition was observed with HA receptor-negative HEK293 cells. Biocompatibility of.the nanocarrier was evaluated through cytotoxicity assays with HEK293 and MCf.7 ceils. The nanocarrier exhibited very low to no cytotoxicity, whereas the DOX-loaded nanocarrier showed considerable cellular uptake and enhanced MCf.7 breast cancer cell-killing ability. We also conf.rmed the f.asibility of.using the highly f.uorescent nanoconj.gate f.r bioimaging of.MCf.7 and HeLa cells. The superior targeted drug delivery ef.icacy, cellular imaging capability, and low cytotoxicity position this nanoconj.gate as an exciting new nanoplatf.rm with promising biomedical applications.

关键词： Cd nanoclusters hyaluronic acid targeted drug delivery f.uorescence bioimaging nanocarrier

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Instability and sensitivity analysis of.f.ows using Openf.AM~

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Chinese j.urnal of.Aeronautics 2016年第2期29卷 316-325页

作者： Liu Qiong f. gome. j.M. Perez V. Theof.lis School of.Aeronautics Universidad PolitOcnica de Madrid Plaza Cardinal Cisneros 3 Madrid E-28040 Spain Department of.Mechanical and Aerospace Engineering Monash University Victoria 3800 Australia

The present contributions deal with the development and implementation of.the direct and adj.int incompressible Navie-Stokes equations in a matrix-f.ee time-stepping context making use of.the open-source Openf.AM~ （open source f.eld operation and manipulation） C ＋＋ tool- box. It is shown that a f.w minor modif.cations in the source code can enable these multi-purpose computational f.uid dynamics （Cf.） solvers to carry out global instability analysis of.three- dimensional f.ows of.engineering interest, exploiting all additional capabilities of.such codes. The strength of.this methodology is demonstrated through the analysis of.an interesting selection of.ooen and wall-bounded f.ows.

关键词： Adj.int-based analysis Computational f.uid dynam-ics f.ow instability Openf.AM Time-stepping method

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The ef.ect of.social context and social scale on the perception of.relationships in monk parakeets

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Current Zoology 2015年第1期61卷 55-69页

作者： Elizabeth A. HOBSON Darlene j. j.HN Tif.any L. MCINTOSH Michael L. AVERY Timothy f. WRIGHT National Institute f.r Mathematical and Biological Synthesis University of Tennessee Knoxville TN 37996-3410 USA Department of.Biology New Mexico State University Las Cruces NM 88003USA USDA Wildlif. Services National Wildlife Research Center Gainesville FL 32641USA

Social relationships f.rmed within a network of.interacting group members can have a prof.und impact on an indi- vidual＇s behavior and f.tness. However, we have little understanding of.how individuals perceive their relationships and how this perception relates to our external measures of.interactions. We investigated the perception of.af.iliative and agonistic relation- ships at both the dyadic and emergent social levels in two captive groups of.monk parakeets （Myiopsitta monachus, n = 21 and 19） using social network analysis and playback experiments. At the dyadic social scale, individuals directed less aggression to- wards their strong af.iliative partners and more aggression towards non-partner *** the emergent social scale, there was no association between relationships in dif.erent social contexts and an individual＇s dominance rank did not correlate with its popularity rank. Playback response pattems were mainly driven by relationships in af.iliative social contexts at the dyadic scale. In both groups, individual responses to playback experiments were signif.cantly af.ected by strong af.iliative relationships at the dyadic social scale, albeit in dif.erent directions in the two groups. Response pattems were also af.ected by af.iliative relation- ships at the emergent social scale, but only in one of.the two groups. Within af.iliative relationships, those at the dyadic social scale were perceived by individuals in both groups, but those at the emergent social scale only af.ected responses in one group. These results provide preliminary evidence that relationships in af.iliative social contexts may be perceived as more important than agonistic relationships in captive monk parakeet groups. Our approach could be used in a wide range of.social species and comparative analyses could provide important insight into how individuals perceive relationships across social contexts and social scales [Current Zoology 61 （1）： 55-69, 2015].

关键词： Af.iliative Agonistic Dominance Eigenvector centrality Emergent social property Myiopsitta monachus Parrot Popularity Rank Social network analysis

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f. SIMULATION Of.CENTER CRACK OCCURRENCE IN TUBE ROUNDS DURING TWO-ROLL ROTARY ROLLING PROCESS

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Acta Metallurgica Sinica(English Letters) 2007年第3期20卷 225-234页

作者： S.Z. Li j. Xu Y.D. Yin j.G. Xue f. Pan j.M. Zheng j.H. Yoon Department of.Materials f.rming and Control Engineering Anhui University of Technology Ma＇anshan 243002 China Provincial Key Laboratory of.Metals and Processing Ma＇anshan 243002 China Steel Tube ＆ Pipe Company of.Bao Steel Co. Ltd. Shanghai 200941 China Department of.Metallurgy and Materials Science Changwon National University Changwon 641-773 Korea

With the aid of.f. （f.nite element） code *** 2005, 2-D coupled thermo-mechanical simulation of.center-crack occurrence in round billet during 2-roll rotary rolling process was presented using Oyane ductile f.acture criteria. A simple modeling is put f.rward based on the spiral motion of.the workpiece as an essential characteristic in movement. The inf.uence of.the f.ed angle and the entry cone angle of.the main roll on the process was taken into account in the modeling. The soundness f.r simplif.ing the 3-D rotary rolling into a 2-D problem was discussed. By adopting the parameters of.Diescher piercer in 140mm mandrel mill of.Bao Steel, the distribution and development of.strain/stress were analyzed, and the eigen value of.ductile f.acture as well. The critical percentage of.diameter reduction was obtained f.om the simulation. The result showed a good agreement with the experimental value, and theref.re was of.widely guiding signif.cance to the practical process f.r rationally f.rmulating the def.rmation parameters of.steel tube piercing.

关键词： numerical simulation inside crack, tube piercing rotary rolling seamless tube def.rmation

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