检索结果-南通市图书馆

Synthesis of coral-like structures of Pr-Yb co-doped YIG: Structural,optical, magnetic and antimicrobial properties

Journal of Rare earths 2024年第3期42卷 543-554,I0004页

作者： A.Fernandez Francisca P.Araujo Y.Guerra S.Castro-Lopes J.Matilla-Arias Idglan S.de Lima edson C.Silva-Filho Josy A.Osajima F.Guerrero R.Pena-Garcia Federal University of Piau Graduate Program in Materials Science and EngineeringTeresinaPIBrazil Federal Rural University of Pernambuco Academic Unit of Cabo de Santo AgostinhoCabo de Santo AgostinhoPEBrazil Federal University of Piaui Department of PhysicTeresinaPBrazil Federal University of Pernambuco Graduate Program in Materials ScienceRecifePEBrazil University of Granma Departmentof Basic Sciences and Applied InformaticsFaculty of Technical SciencesBayamoCuba Federal University of Amazonas Department of PhysicManausAMBrazil Federal University of Pernambuco Department of PhysicRecifePEBrazil

Coral-like structures of the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12),(0.00 ≤ x ≤ 0.04, 0.00 ≤ y ≤ 0.02) compound were synthesized using the sol-gel method. Structural investigation certified the YIG cubic crystal structure formation, without any secondary phase. It is shown that, the relatively large ionic radius of the dopant cations results in an expansion of the lattice parameter, variations in the Iona-O-Iondangle, Iona-O,Iond-O and Ionc-O bond distances and decrease in the average crystallite size. Fourier transform infrared(FTIR) and Raman measurements are essential to testify the single-phase formation of YIG crystal structure and are observed changes in the stretching and vibrational modes, respectively. The morphological study, energy dispersive spectroscopy(eDS) spectra and textural properties show corallike structures, peaks associated with Pr^(3+) and Yb^(3+) atoms and the effect of dopants on surface area,diameter, and pore volume, respectively. The optical analysis from diffuse reflectance spectra witnessed an increase in the optical gap band, a decrease in Urbach energy and blue shift in the charge transfer,correlated with the expansion of the unit cell due to the dopant's insertion in the YIG structure. A typical ferrimagnetic behavior is exhibited by the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12)compound. The saturation magnetization(M_(s)), cubic anisotropy constant(K_(1)) and coercive field(H_(c)) increase with the Pr^(3+)cations content, as consequence of their magnetic nature and distribution around of Fe^(3+)ions due to the coexistence with the Yb^(3+). Finally, for the first time, antibacterial tests by mean of the direct contact method were performed for YIG co-doped with Pr^(3+)and Yb^(3+)and it is shown that, relatively high dosages of Pr^(3+) cations favored the activity against S. aureus, therefore, a new biological property for YIG doped with rare earths is presented.

关键词： Yttrium iron garnet(YIG) Coral-like structures Rare earths Band gap energy Magnetic properties Antimicrobial properties

来源：

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

Improvement of carbon fiber surface properties using electron beam irradiation

引用

Nuclear Science and Techniques 2007年第1期18卷 39-41页

作者： eddy Segura PINO Luci Diva Brocardo MACHADO Claudia GIOVeDI Instituto de Pesquisas energéticas e Nucleares-IPeN/CNeN-SP Av.Prof.Lineu Prestes2242Cidade Universitária05508-000Sāo PauloSP-Brazil Centro Tecnológico da Marinha em Sāo Paulo Av.Prof.Lineu Prestes2468Cidade Universitária05508-000Sāo PauloSP-Brazil

Carbon fiber-reinforced advance composites have been used for structural applications,mainly on account of their mechanical *** main factor for a good mechanical performance of carbon fiber-reinforced com- posite is the interfacial interaction between its components,which are carbon fiber and polymeric *** aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant *** radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical *** results showed that eB irradiation improved the ten- sile strength of carbon fiber *** maximum value in tensile strength was reached using doses of about 250 *** breakage,the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated car- bon fibers were *** micrographs showed modifications on the carbon fiber surface.

关键词：碳纤维表面性质电子束辐射改性

来源：

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

Probe-based confocal endomicroscopy is accurate for differentiating gastric lesions in patients in a Western center

引用

Chinese Journal of Cancer Research 2018年第5期30卷 546-552页

作者： adriana vaz safatle-ribeiro elisa ryoka baba rodrigo corsato scomparin sheila friedrich faraj marcelo simas de lima luciano lenz bruno costa martins carla gusmon fábio shiguehissa kawaguti caterina pennacchi bruno zilberstein ulysses ribeiro jr. fauze maluf-filho endoscopy Unit of department of Gastroenterology Sao Paulo Cancer Institute University of Sao Paulo Medical School (ICESP-HCFMUSP) Sao Paulo 01246-000 Brazil

Objective： Probe-based confoeal laser endomicroscopy （pCLe） technique may improve the diagnosis of gastric mucosal lesions allowing acquisition of high-resolution in vivo images at the cellular and mierovaseular levels. This study aims to evaluate the accuracy of pCLe for the differential diagnosis of non-neoplastic and neoplastic gastric ***： Twenty gastric mucosal lesions from 10 patients were evaluated during endoscopic procedure and were examined by pCLe. Diagnostic pCLe was followed by biopsies or endoscopic resection of suspected lesions. A senior pathologist evaluated the specimens and was blinded to the pCLe ***： Patients＇ mean age was 68.3 （range, 42-83） years and six were men. Thirteen suspicious flat or elevated lesions （classified as 0-Is, 0-IIa or 0-IIa ＋ IIc） and seven pre-malignant lesions （atrophy and intestinal metaplasia） were evaluated. One patient was studied during his long-term follow-up after partial gastrectomy and presented severe atrophy, intestinal metaplasia, and xanthomas at the stump mucosa. The location of gastric lesions was in the body （n=10 lesions）, the antrum （n=9） and the incisura angularis （n=1）. All neoplastic lesions and all but one benign lesion were properly diagnosed by pCLe. pCLe incorrectly diagnosed one small antrum lesion as adenoma, however the final diagnosis was intestinal metaplasia. The final histological diagnosis was neoplastic in 9 and benign lesions in 11. In this small case series, pCLe accuracy was 95% （19/20 lesions）.Conclusions： pCLe is accurate for real time histology of gastric lesions, pCLe may change the management of patients with gastric mucosal lesions, guiding biopsies and endoscopic resection, and avoiding further diagnostic workup or unnecessary therapy.

关键词： Probe-based confocal endomieroscopy gastric cancer intestinal metaplasia atrophy gastric adenoma endoscopic resection

来源：

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

Kinetic Rates of the Fischer Tropsch Synthesis on a Co/Nb_2O_5 Catalyst

引用

Journal of Natural Gas Chemistry 2006年第4期15卷 307-312页

作者： Víctor R.Ahón Paulo L.C.Lage Carlos D.D.de Souza Fabiana M.Mendes Martin Schmal Federal University of Rio de Janeiro Programa de engenharia Química COPPE/UFRJ C.P.6850221941-972Rio de JaneiroRJBrazil

The kinetics of the Fischer-Tropsch reaction over a Co/Nb2O5 catalyst in a fixed bed reactor was investigated experimentally. experiments were carried out under isothermal and isobaric conditions （T=543 K, P=2.1 MPa） and under different conditions of several H2/CO feed molar ratio （0.49-4.79）, space velocities （0.2-3.8 h^-1）, mass of catalyst （0.3-1.5 g）, and CO conversion （10%-29%）. Synthesis gas conversion was measured and data were reduced to estimate the kinetic parameters for different Langmuir-Hinshelwood rate expressions. Differential and integral reactor models were used for the nonlinear regression of kinetics parameters. One of the rate equations could well explain the data. The hydrocarbon product distributions that were experimentally determined exhibited an unusual behavior, and a possible explanation was discussed.

关键词： Fischer-Tropsch natural gas kinetics selectivity

来源：

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

Influence of fibre and betaine on development of the gastrointestinal tract of broilers between hatch and 14 d of age

引用

Animal Nutrition 2019年第2期5卷 163-173页

作者： Tiago T.dos Santos Sthéfanie C.Dassi Celia R.C.Franco Cleber R.V.da Costa Sophie A.Lee Ana V.Fisher da Silva Universidade Federal do Parana Curtiba81531-900Brazil department of Cell Biology Universidade Federal do ParanaCuritiba81531-900Brazil AB Vista MarlboroughWiltshireSN8 4ANUnited Kindom department of Cell Biology Universidade Federal do ParanaCuritiba81531-900Brazil

An experiment was designed to determine the influence of fibre and betaine on the development of the intestine, liver and pancreas of broilers from hatch to 14 d of age. A total of 250-day-old Cobb 500 male broilers were allocated to 16 cages with 15 broilers each. Treatments were arranged in a 2 x 4 factorial design, consisting of 2 feed formulations(low and high fibre diets) and 4 levels of betaine(0,1, 3 or 5 kg/t). At hatch, 10 birds in total were euthanised, and samples of the liver, pancreas, yolk sac and intestine were collected for reference of the analysed parameters before the start of the *** d 4.9 and 14, 5 birds per cage(10 birds per treatment) were selected, euthanised and treated as the same as the birds at hatch. Villus height and width and crypt depth were determined on the duodenum samples, and absorptive area was calculated. The number of enterocytes in mitosis at the villus was determined by a positive reaction to antibody for Ki67 protein, and fused villus was evaluated visually. The relative weight of the yolk sac reduced(P ed while the intestine and liver reached a maximum(P e pancreas at d 9. Birds fed the high fibre diet had greater feed intake, lower relative weight of the pancreas and higher villus(P ed the low fibre diet. Villus width increased(P e, and this was associated with fused villus. Betaine inclusion reduced(P eased(P e and absorptive area, and reduced(P e number of enterocytes with positive reaction for the antibody *** inclusion reduced the width and increased the absorptive area and the villus height of the duodenum of birds up to 14 d of age. The higher fibre diet increased feed intake and villus height, yet reduced pancreas relative weight, while not affecting body weight gain. This response was possibly due to a dilution effect of the fibre, reducing nutrient absorption

关键词： Broiler Betaine Fibre Intestine maturation Pancreas Liver

来源：

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

experimental investigation on variability in properties of Amazonian wood species Muiracatiara ( Astronium lecointei ) and Maçaranduba ( Manilkara huberi ) focusing guitar fingerboards manufacturing

引用

Journal of Bioresources and Bioproducts 2021年第1期6卷 33-38页

作者： Roseli Felix da Silva Ribeiro JoséFlávio Silveira Feiteira Jayme Pereira de Gouvê Alexandre Furtado Ferreira Federal Fluminense University PPGEMVolta RedondaRJBrazil Federal Fluminense University PGMECVolta RedondaRJBrazil

In face of scarcity in the supply of non-traditional Brazilian woods properly treated for use in high quality musical instruments,pieces of Amazonian wood species muiracatiara(Astronium lecointei)and maçaranduba(Manilkara huberi)purchased in the common internal Brazilian timber market were *** species were pre-selected for use in fingerboards of acoustic and electric guitars due to similar properties with ebony(Diospyros crassiflora).Variabilities of elastic modulus parallel to grain and density were investigated inside wooden *** addition,referred parameters were used in calculation of speed of *** tests were performed in order to compare both species and revealed inequality for variances of dynamic elastic modulus(e_(d))and speed of sound,but equality for *** of means was also examined via unequal variance *** color differences,lower variability of *** led to the indication of this species as likely capable to substitute satisfactorily ebony in fingerboards manufacturing.

关键词： Mechanical properties variability Wood grain slope experimental analysis Impulse excitation technique F-test

来源：

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

enzymatic Hydrolysis of Sugarcane Biomass and Heat Integration as enhancers of ethanol Production

引用

Journal of Renewable Materials 2018年第2期6卷 183-194页

作者： Reynaldo Palacios-Bereche Adriano ensinas Marcelo Modesto Silvia Nebra Centre of engineering Modelling and Applied Social SciencesFederal University of ABC(CECS/UFABC)Santo AndréSPBrazil energy department Federal University of LavrasLavras MGBrazil Interdisciplinary Centre of energy Planning University of Campinas(NIPE/UNICAMP)CampinasSPBrazil

The aim of this study is to assess the possibility of increasing ethanol production by introducing the bagasse hydrolysis process into conventional *** were performed for mass and energy balances using Aspen Plus?*** was assumed that sugarcane trash and lignin cake—hydrolysis process residues—are available as supplementary *** cases were evaluated,including:(a)conventional ethanol distillery,(b)conventional plant combined with a hydrolysis process without heat integration,with different solid contents in the hydrolysis reactor,and(c)conventional plant combined with the hydrolysis process applying heat integration by pinch *** highest ethanol yield was achieved in the case of heat integration and concentration of cellulose hydrolysate by the membrane system with a solid content of 5%in the hydrolysis *** represents an increase of 22%over conventional distilleries currently found in the industry.

关键词： ethanol sugarcane enzymatic hydrolysis heat integration

来源：

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

exergames： neuroplastic hypothesis about cognitive improvement and biological effects on physical function of institutionalized older persons

引用

Neural Regeneration Research 2016年第2期11卷 201-204页

作者： Renato Sobral Monteiro-Junior Cesar Augusto Otero Vaghetti Osvaldo Jose M. Nascimento Jerson Laks Andrea Camaz deslandes Physical education and Sport department of the Universidade estadual de Montes Claros Minas GeraisBrazil Post Graduation Program(PhD)in Medicine(Neurology-Neuroscience) Universidade Federal FluminenseNiteroiBrazil Neuroscience Laboratory of exercise Universidade Federal do Rio de JaneiroRio de JaneiroBrazil Higher School of Physical education Universidade Federal de PelotasPelotasBrazil Neurology department Universidade Federal FluminenseNiteroiBrazil Programa de Pos-graduacao em Biomedicina Translacional-Biotrans Universidade UnigranrioBrazil Institute of Psychiatry UniversidadeFederal do Rio de JaneiroRio de JaneiroBrazil Centro de estudos e Pesquisa do envelhecimento Instituto Vital BrasilRio de JaneiroBrazil Institute of Physical education and Sport Universdiade do Estado do Rio de JaneiroRio de JaneiroBrazil

exergames can be considered a dual task because the games are performed by a man-videogame interface, requiring cognitive and motor functions simultaneously. Although the literature has shown improvements of cognitive and physical functions due to exergames, the intrinsic mechanisms involved in these functional changes have still not been elucidated. The aims of the present study were（1） to demonstrate the known biological mechanisms of physical exercise regarding muscle adaptation and establish a relationship with exergames; and（2） to present a neurobiological hypothesis about the neuroplastic effects of exergames on the cognitive function of institutionalized older persons. These hypotheses are discussed.

关键词： virtual reality elderly nursing-home physical activity cognition neuroplasticity

来源：

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

Study of the Superficial Modification of Sisal Fibres with Lignin, and Its Use As a Reinforcement Agent in Cementitious Composites

引用

Journal of Renewable Materials 2020年第8期8卷 891-903页

作者： Plínio B.Mundim Rondinele A.R.Ferreira Leila A.C.Motta Mariana A.Henrique Daniel Pasquini College of Civil engineering Federal University of UberlândiaUberlândia38400-902Brazil Chemistry Institute Federal University of UberlândiaUberlândia38400-902Brazil

The objective of this work was to evaluate different superficial treatments of sisal fibres employing lignin,and their use as a reinforcement agent in cementitious *** treatments consisted of superficially impregnating sisal fibres(S)with organosolv lignin(LO),organosolv lignin and glutaraldehyde(LOG),Kraft lignin(LK)and Kraft lignin and glutaraldehyde(LKG).The fibre modifications were verified by FTIR-ATR and SeM analyzes,and the presence of lignin on the surface of the fibres was evidenced,confirming the effectiveness of the *** mechanical,thermal(by TGA)and water absorption properties of the fibres before and after the modifications were also *** treatment,the modified fibres presented an expressive reduction of the water absorption and did not show significant changes in the mechanical properties when compared with the natural unmodified sisal fibre(SNAT).It was verified an increase in the thermal stability of the treated fibres which can be attributed to the insertion of lignin on the *** evaluate the performance of the fibres in the cementitious composites,cement plates(CP)were produced with different treated fibres(CP-SLOG,CP-SLO,CP-SLKG,CP-SLK)and fibres without treatment(CP-SNAT).The composites were evaluated concerning to the water absorption,porosity and mechanical *** fractured regions were also investigated by *** composites prepared showed similar values of absorption and porosity *** the mechanical properties,the composites prepared with modified fibres showed a significant increase in the modulus of rupture and modulus of elasticity compared with CP-SNAT,while toughness was similar to all *** the SeM images,it was observed that the modified fibres immersed in the cementitious plates showed no degradation,indicating that the impregnation of lignin acted as a protective agent of the ***,the treatments of the fibres with lignin led to a significant improvement in th

关键词： Cementitious composites sisal lignin surface modification

来源：

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

Oxidative dehydrogenation of propane under steady-state and transient regimes over alumina-supported catalysts prepared from mixed V_2W_4O_(19)^(4-) hexametalate precursors

引用

Journal of Natural Gas Chemistry 2010年第2期19卷 123-133页

作者： Sébastien Paul elise Berrier Marcia Cristina Kaezer Frana Jean-Guillaume eon Univ Lille Nord de France F-59000 LilleFrance eCLille UCCSF-59650 Villeneuve d'AscqFrance CNRS UMR 8181F-59650 Villeneuve d'AscqFrance USTL UCCSF-59650 Villeneuve d'AscqFrance Instituto de Quimíca Universidade Federal do Rio de Janeiro-Cidade UniversitáriaIlha do Fundo21945-970 Rio de JaneiroBrazil

An integrated approach combining the development of an innovative catalyst and the research of a set of adequate operating conditions for the propane oxidative dehydrogenation （ODH） is *** experimental set-up,specially designed for steady-state and transient studies is *** preparation method,the characterization and the performances in steady-state and transient regimes of catalysts based on V2W4O194-Lindqvist isopolyanion used as a precursor and supported on alumina are *** influence of the preparation method of the catalyst and the role of water in the feed gas are more particularly discussed.

关键词： propane oxidative dehydrogenation (ODH) transient regime pulsed reactor Lindqvist isopolyanion in-situ Raman

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：