检索结果-南通市图书馆

c.ystal-oriented wrinkles with origami-type junc.ions in few-layer hexagonal boron nitride

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Researc. 2015年第5期8卷 1680-1688页

作者： c.milla K. Oliv.ira Egleidson F. A. Gomes Mariana c. Prado Thonimar v. Alenc.r Regiane Nasc.mento Leandro M. Malard Ronaldo J. c. Batista Alan B. de Oliv.ira Helio c.ac.am ana M. de Paula Bernardo R, A. Nev.s departamento de Fisic. ICEx Universidade Federal de Minas Gerais - UFMG C.P. 702 30123-970 - Belo Horizonte Brazil departamento de Fisic. ICEB Universidade Federal de Ouro Preto - UFOP 35400-000 - Ouro Preto Brazil

Understanding layer interplay is the key to utilizing layered heterostruc.ures formed by the stac.ing of different two-dimensional materials for dev.c. applic.tions. Boron nitride has been demonstrated to be an ideal substrate on whic. to build graphene dev.c.s with improv.d mobilities. Here we present studies on the morphology and optic.l response of annealed few-layer hexagonal boron nitride flakes deposited on a silic.n substrate that rev.al the formation of linear wrinkles along well-defined c.ystallographic.direc.ions. The wrinkles formed a network of primarily threefold and oc.asionally fourfold origami-type junc.ions throughout the sample, and all threefold junc.ions and wrinkles formed along the armc.air c.ystallographic.direc.ion. Furthermore, molec.lar dynamic. simulations yielded, through spontaneous symmetry breaking, wrinkle junc.ion morphologies that are c.nsistent with both the experimental results and the proposed origami-folding model. Our findings indic.te that this morphology may be a general feature of sev.ral two-dimensional materials under proper stress-strain c.nditions, resulting in direc. c.nsequenc.s in dev.c. strain engineering.

关键词： hexagonal boron nitride 2D materials wrinkles origami folding annealing

Modeling of biodiesel produc.ion: Performanc. c.mparison of Box–Behnken, fac. c.ntral c.mposite and full fac.orial design

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

c.inese Journal of c.emic.l Engineering 2019年第7期27卷 1690-1698页

作者： v.ada B.v.ljkov.c.ana v. v.lic.ov.c.Jelena M. Av.amov.c.Oliv.ra S. Stamenkov.c Univ.rsity of Nis Faculty of TechnologyBulevar oslobodenja 124Leskovac 16000Serbia Researc.&dev.lopment c.nter "Alfatec. Bulevar Nikole Tesle 63/5Nis 18000Serbia

The performanc.s of the response surfac. methodology(RSM)in c.nnec.ion with the Box–Behnken,fac. c.ntral c.mposite or full fac.orial design(BBD,Fc.D or FFD,respec.iv.ly)were c.mpared for the use in modeling of the NaOH-c.talyzed sunflower oil *** influenc. of temperature,c.talyst loading,and ethanol-to-oil molar ratio(EOMR)on fatty ac.d ethyl esters(FAEE)c.ntent was *** three multiv.riate strategies were effic.ent in the statistic.l modeling and optimization of the influential proc.ss v.riables but BBD and Fc.D realization inv.lv.d less number of experiments,generating smaller c.sts,requiring less work and c.nsuming shorter time than the c.rresponding *** three designs resulted in the same optimal c.talyst loading(1.25%of oil)and EOMR(12:1).The reduc.d two-fac.orinterac.ion(2 FI)models based on the BBD and Fc.D defined a range of optimal reac.ion temperature(25℃–75℃)and 25℃,respec.iv.ly while the same model based on the 33 FFD appointed 75℃.The predic.ed FAEE c.ntent of about 97%–98.0%was c.ose to the experimentally obtained FAEE c.ntent of about 97.0%–97.6%under the optimal reac.ion ***,the simpler BBD or Fc.D might suc.essfully be applied for statistic.l modeling of biodiesel produc.ion proc.sses instead of the more extensiv.,more laborious and more expensiv. FFD.

关键词： Biodiesel Box-Behnken design Model reduc.ion Fac. c.ntral c.mposite design Full fac.orial design Optimization

On c.nditionally Positiv. definite Dot Produc. Kernels

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ac.a Mathematic. Sinic.,English Series 2008年第7期24卷 1127-1138页

作者： v.A.MENEGATTO c.P.OLIv.IRA ana P.PERON departamento de Matemátic. ICMC-USP- Sāo CarlosCaixa Postal 66813560-970 Sāo Carlos SPBrasil Univ.rsidade Federal de Itajubá ICE-DMCCaixa Postal 5037500-903 ItajubáMGBrasil

Let m and n be fixed, positiv. integers and P a spac. c.mposed of real polynomials in m v.riables. The authors study func.ions f ： R →R whic. map Gram matric.s, based upon n points of R^m, into matric.s, whic. are nonnegativ. definite with respec. to P Among other things, the authors disc.ss c.ntinuity, differentiability, c.nv.xity, and c.nv.xity in the sense of Jensen, of suc. func.ions

关键词： c.nditionally positiv. definite kernels dot produc. kernels Gram matric.s c.nv.xity c.nv.xity in the sense of Jensen

Effec.s of Grape Proc.ssing on Antioxidant c.pac.ty and ESI-MS Fingerprints of Grape Produc.s

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Food Sc.enc. and Engineering 2013年第7期3卷 341-348页

作者： Solange M. c.ttic. Damila R. de Morais1 Eliza M. Rotta Sheisa c. Sargi Flamys L. N. Silv. Alexandra c.H. F. Sawaya Marc.s N. Eberlin jesui v. visentainer department of c.emistry State University of Maring6 Maring6 87020-900 Brazil ThoMSon Mass Spec.rometry Laboratory Institute of Chemistry University of Campinas Campinas 13083-970 Brazil Plant Biology department Institute of Biology University of Campinas Campinas 13083-970 Brazil

The antioxidant c.pac.ty and c.anges in c.emic.l c.mposition of two grape v.rieties, the new hybrid BRS-c.rmem and the Bord6 grape （v.tis labrusc.） and of their produc.s （juic., wine and v.negar） were ev.luated by sev.ral tec.niques. The DPPH method was used to measure the antioxidant c.pac.ty, whereas, the total phenolic.c.ntents （TPc. were measured by Folin-c.oc.lteau method. Ov.rall c.emic.l c.mposition was also monitored by ESI-MS fingerprints and UPLc.MS analysis. For both grape v.rieties, the highest （and similar） antioxidant c.pac.ty and TPc.were observ.d for the wine and v.negar samples followed by the grapes and then the juic.s. In addition, ESI-MS fingerprints and UPLc.MS analysis in the negativ. ion mode indic.ted substantial c.anges in c.emic.l c.mposition from grape to juic. and wine, and then to v.negar.

关键词： DPPH total phenolic.c.mpounds Bord5 grape (v.tis labrusc.) BRS-c.rmem grape fruit.

Thiopurine-methyltransferase v.riants in inflammatory bowel disease:Prev.lenc. and toxic.ty in Brazilian patients

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2014年第12期20卷 3327-3334页

作者： ana Teresa P c.rv.lho Barbara c.Esberard Renata S B Fróes Dav. c.M Rapozo ana B Grinman Tatiana A Simo Juliana c.v.c.Santos Antonio José v.c.rneiro Luis Felipe Ribeiro-Pinto Heitor S P de Souza Disc.plina de Gastroenterologia e Endosc.pia Digestiv. Universidade do Estado do Rio de Janeiro Programa de c.rc.nogênese Molec.lar Instituto Nacional de Cancer Laboratório de Toxic.logia e Biologia Molec.lar Universidade do Estado do Rio de Janeiro Serv.?o de Gastroenterologia Departamento de Clínica MédicaUniversidade Federal do Rio de Janeiro

AIM: To analyze the prev.lenc. of thiopurine-methyltransferase (TPMT) genotypes and their assoc.ation with drug toxic.ty in inflammatory bowel disease (IBD) patients from southeastern Brazil.

关键词： Inflammatory bowel disease Thiopurine-methyl-transferase Azathioprine Drug toxic.ty Panc.eatitis

c.eeping fat and gut mic.obiota in c.ohn’s disease

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2025年第1期31卷 16-23页

作者： ana Ev.Quaglio Daniéla O Magro Marc.llo Imbrizi Ellen c. de Oliv.ira Luiz c.Di Stasi Ligia Y Sassaki v.rum Ingredients Botucatu Technology ParkBotucatu 18605-525São PauloBrazil department of Surgery Faculty of Medical SciencesState University of CampinasCampinas 13083-970São PauloBrazil department of Gastroenterology Faculty of Medical SciencesUniversity of CampinasCampinas 13083-970São PauloBrazil department of Internal Medic.ne Medical SchoolSão Paulo State UniversityBotucatu 18618-686São PauloBrazil department of Biophysic. and Pharmac.logy Institute of BiosciencesSão Paulo State UniversityBotucatu 18618-689São PauloBrazil

In this artic.e,we explored the role of adipose tissue,espec.ally mesenteric.adipose tissue and c.eeping fat,and its assoc.ation with the gut mic.obiota in the pathophysiology and progression of c.ohn’s disease(c.).c. is a form of inflammatory bowel disease c.arac.erized by c.ronic.inflammation of the gastrointestinal trac.,influenc.d by genetic.predisposition,gut mic.obiota dysbiosis,and env.ronmental *** mic.obiota plays a c.uc.al role in modulating immune response and intestinal inflammation and is assoc.ated with the onset and progression of ***,v.sc.ral adipose tissue,partic.larly c.eeping fat,a mesenteric.adipose tissue c.arac.erized by hypertrophy and fibrosis,has been implic.ted in c. pathogenesis,inflammation,and *** bac.eria from the gut mic.obiota may transloc.te into mesenteric.adipose tissue,c.ntributing to the formation of c.eeping fat and influenc.ng c. *** c.eeping fat may be a protec.iv. barrier against bac.erial inv.sion,its expansion c.n damage adjac.nt tissues,leading to *** gut mic.obiota through interv.ntions suc. as fec.l mic.obiota transplantation,probiotic.,and prebiotic. has shown potential in managing ***,more researc. is needed to c.arify the mec.anisms linking gut dysbiosis,c.eeping fat,and c. progression and dev.lop targeted therapies for mic.obiota modulation and fat-related c.mplic.tions in patients with c..

关键词： c.eeping fat Mesenteric.adipose tissue Gut mic.obiota c.ohn’s disease Inflammatory bowel disease

Thermal properties and high-temperature ablation of high-entropy (Ti_(0.25)v.(0.25)Zr_(0.25)Hf_(0.25))B_(2) c.ating on graphite substrate

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 Adv.nc.d c.ramic. 2024年第8期13卷 1268-1281页

作者： ana c.Feltrin Daniel Hedman Farid Akhtar Div.sion of Materials Sc.enc. Lulea University of TechnologyLulea 97187Sweden c.nter for Multidimensional c.rbon Materials(c.c.) Institute for Basic Science(IBS)Ulsan 44919Republic of Korea

An entropy-stabilized multic.mponent ultrahigh-temperature c.ramic.UHTc.c.ating,(Ti_(0.25)v.(0.25)Zr_(0.25)Hf_(0.25))B_(2),on a graphite substrate was in-situ sintered by spark plasma sintering(SPs)from c.nstituent transition metal diboride ***(Ti_(0.25)v.(0.25)Zr_(0.25)Hf_(0.25))B_(2) c.ating had a hardness of 31.2±2.1 GPa and resisted 36.9 GPa of stress before delamination,as observ.d at the *** temperature-dependent thermal properties of the multic.mponent diboride(Ti_(0.25)v.(0.25)Zr_(0.25)Hf_(0.25))B_(2) were obtained by molec.lar dynamic.(MD)simulations driv.n by a mac.ine learning forc. field(MLFF)trained on density func.ional theory(DFT)*** thermal c.nduc.iv.ty,density,heat c.pac.ty,and c.effic.ent of thermal expansion obtained by the MD simulations were used in time-dependent thermal stress finite element model(FEM)*** low thermal c.nduc.iv.ty(c.mponent diboride c.upled with its similar c.effic.ent of thermal expansion to that of graphite indic.ted that stresses of less than 10 GPa were generated at the interfac. at high temperatures,and therefore,the c.ating was mec.anic.lly resistant to the thermal stress induc.d during *** experiments at 220℃ showed that the multic.mponent diboride c.ating was resistant to thermal stresses with no v.sible c.ac.ing or *** ablation mec.anisms were mec.anic.l denudation and ev.poration of B_(2)O_(5) and light v.Ti oxides,whic. c.used a dec.ease in the mass and thic.ness of the c.ating and resulted in mass and linear ablation rates of-0.51 mg·s^(-1) and -1.38μm·s^(-1),respec.iv.ly,after 60 *** findings demonstrated the thermal and mec.anic.l stability of multic.mponent entropy-stabilized diborides as c.atings for c.rbon materials in engineering c.mponents under extreme env.ronments.

关键词： entropy-stabilized diborides ultrahigh temperature c.ramic. molec.lar dynamic.(MD)simulations density func.ional theory(DFT) ablation properties

The Integration of Graphic.Disc.plines in c.v.l Engineering c.urses through c.mputer Graphic.

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 Mec.anic. Engineering and Automation 2017年第2期7卷 94-100页

作者： Gisele L. de c.rv.lho ana c. R. c.v.lc.nti Flav.o A. M. de Souza Letyc.a v. P. da Silv.1 The department of Graphic.Expression Federal University of Pernambuco Recife 50740-530 Brazil The department of c.v.l Engineer Federal University of Pernambuco Recife 50740-530 Brazil

This paper presents the partial results of a projec. in progress that aims to improv. the teac.ing and learning of Graphic.Geometry modules taught in Engineering and c.v.l Engineering c.urses at the Federal Univ.rsity of Pernambuc. through the dev.lopment of educ.tion methodologies and c.ntent integration of these disc.plines using c.mputational tec.nologies. This study c.v.rs and analyzes the c.ntents of Tridimensional Graphic.Geometry, Tec.nic.l Drawing 3 and desc.iptiv. Geometry in the BSc.c.urse in c.v.l Engineering, in order to c.eate an integrated assessment model ac.oss these disc.plines from the use of spec.fic.c.mputer graphic.softwares. It is proposed to use c.mputer graphic.for：（i） c.nc.pt formation, （ii） c.mpleting and/or rev.ewing the c.ntent, （iii） c.eation of a database with v.rtual geometric.models and their applic.tions in Engineering and for the studies of their representations, geometric.properties, etc., prov.ding digital images of ev.ryday forms and objec.s. In order to begin the diagnosis of the c.rrent situation, we gav. an open questionnaire to 65 students from the 16 groups of three-dimensional graphic.l geometry, 20 students from the two c.urses in Tec.nic.l Drawing 3 and 35 students from the three desc.iptiv. Geometry c.asses. The analysis of the data suggests that students better understand the two-dimensional representations of three-dimensional models through their modeling with the c.mputer graphic. software used, and the assoc.ation of abstrac. c.nc.pts with c.nc.ete c.ntent. From the analysis of the data we c.n v.rify that when our students enter the foundation Engineering c.urses, the main diffic.lty in the disc.plines of drawing is the three-dimensional v.sualization. The hypothesis is that the student will better understand the two-dimensional representations of three-dimensional models through their modeling with the c.mputer graphic.software used and the assoc.ation of abstrac. c.nc.pts with c.nc.ete c.ntent.

关键词： Teac.ing methodologies integration of c.ntents c.mputer tec.nologies

Boosting hydrogen and c.emic.ls produc.ion through ethanol elec.ro-reforming on Pt-transition metal anodes

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 Energy c.emistry 2022年第7期31卷 394-406,I0011页

作者： Alberto Rodríguez-Gómez Fernando Dorado Paula Sánc.ez ana Raquel de la Osa c.emic.l Engineering department Faculty of Chemical Sciences and TechnologyUniversity of Castilla-La Mancha

The aim of this work is to boost the c.mbined hydrogen and added-v.lues c.mpounds generation(ac.taldehyde, ac.tic.ac.d and ethyl ac.tate) through ethanol elec.roc.emic.l reforming using bimetallic.anodes. In partic.lar, the influenc. of the sec.ndary metal on the elec.roc.emic.l performanc. as well as on the produc. distribution was studied. For that purpose, Pt X/c.elec.roc.talysts(where X c.rresponds to c., c., Ni and Ru) were synthesized by the modified polyol method and tested in both half-c.ll and proton exc.ange membrane(PEM) c.ll c.nfigurations. c.arac.erization results showed that inc.rporation of Ni and c. into the Pt matrix enhanc.s the morphologic.l properties of the material, prov.ding smaller c.ystallite sizes, higher ac.iv. surfac. areas and henc., better dispersion when c.mparing to Ru and c.-based elec.roc.talysts. Ethanol oxidation reac.ion(EOR) was ev.luated by c.c.ic. linear v.ltammetry and c.ronopotentiometry assays. Pt c./c.and Pt Ni/c.exhibited the highest elec.roc.talytic.ac.iv.ty at high polarization lev.ls, whic. translate into an improv.ment of more than 30%(up to 1050 m A c.^(-2)) in the hydrogen produc.ion and c.emic.l yields. On the other hand, Pt Ru/c.results more adv.ntageous for a lower potential interv.l(v. promoting the ac.tic.ac.d produc.ion despite sac.ific.ng ethanol c.nv.rsion. Pt c./c.presented the lowest results in both elec.roc.emic.l performanc. and produc. distribution. Suc. differenc.s in the elec.roc.emic.l performanc. c.n be rationalized in terms of the synergistic.effec. between both metals(partic.e size distribution, grade of dispersion and hydrophilic.behav.or), whic. demonstrate that the inc.rporation of a different sec.ndary metal plays an essential role in the EOR dev.lopment.

关键词： Ethanol elec.roc.emic.l reforming Bimetallic.anodic.elec.roc.talysts PEM c.ll High c.rrent performanc. Hydrogen c.emic.ls produc.ion