检索结果-南通市图书馆

Pore structure of cementitious material enhanced by graphitic nanomaterial： a critical review

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil engineering 2018年第1期12卷 137-147页

作者： S.A. GHAHARI e. GHAFARI l. ASSI Department of Civil engineering Purdue University USA Department of Civil and environmental engineering University of South Carolina USA

Carbon nano tubes （CNT） has been introduced as an efficient nanomaterial in order to improve the mechanical and durability properties of concrete. The effect of CNT on the microstructures of cementitious materials has been widely reported. This paper combines a critical review on the effect of CNT on the pore and microstructure of cement composite with a discussion on the porosity measurement of pastes containing CNT using mercury intrusion porosimetry techniques （MIP）. It was found that, surface treatment by H2SO4 and HNO3 solution forms carboxyl acid groups on CNTs＇ surfaces that lead to the improvement of reinforcement. In this scope, this review paper involves analyzing the effect of CNT on the microstructure and the pore structure of cementitious materials. The existing methods of measuring the porosity of cementitious material are reviewed, in particular, the contact angle measurement is discussed in detail in which the most effective parameters and possible errors of calculation is presented.

关键词： carbon nano tubes microstructure porosity mercury intrusion porosimetry cement composite

On correction of model of stabilization of distribution of concentration of radiation defects in a multilayer structure with account experiment data

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 Semiconductors 2018年第5期39卷 6-15页

作者： e.l.Pankratov Nizhny Novgorod State University Nizhny Novgorod603950Russia

We introduce a model of redistribution of point radiation defects, their interaction between themselves and redistribution of their simplest complexes（divacancies and diinterstitials） in a multilayer structure. The model gives a possibility to describe qualitatively nonmonotonicity of distributions of concentrations of radiation defects on interfaces between layers of the multilayer structure. The nonmonotonicity was recently found *** take into account the nonmonotonicity we modify recently used in literature model for analysis of distribution of concentration of radiation defects. To analyze the model we used an approach of solution of boundary problems,which could be used without crosslinking of solutions on interfaces between layers of the considered multilayer structures.

关键词： radiation defects nonmonotonicity of distributions of concentrations complex

GUIDeD WAVeS IN MUlTIlAYeReD PlATeS: AN IMPROVeD ORTHOGONAl POlYNOMIAl APPROACH

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2014年第5期27卷 542-550页

作者： Jiangong Yu J.e.lefebvre l.elmaimouni School of Mechanical and Power engineering Henan Polytechnic University Department of Civil engineering University of Siegen Univ lille Nord de France F-59000 Lille France UVHC IEMN-DOAE F-59313 Valenciennes Cedex 9 France CNRS UMR 8520 F-59650 Villeneuve d’Ascq France eRSITA Faculte Polydisciplinaire d’Ouarzazate Univ. Ibn Zohr 45000 Ouarzazate Morocco lMTI Faculte des Sciences d’Agadir Universite Ibn Zohr BP 28/S Agadir Morocco

Conventional orthogonal polynomial approach can solve the multilayered plate only when the material properties of two adjacent layers do not change significantly. This paper de- veloped an improved orthogonal polynomial approach to solve wave propagation in multilayered plates with very dissimilar material properties. Through numerical comparisons among the exact solution, the results from the conventional polynomial approach and from the improved poly- nomial approach, the validity of the improved polynomial approach is illustrated. Finally, it is shown that the conventional polynomial approach can not yield correct continuous normal stress profiles. The improved orthogonul polynomial approach has overcome this drawback.

关键词： multilayered plate orthogonal polynomial dispersion curves stress profiles

A simple and fast method to calculate the coil currents and the external poloidal flux and magnetic field for fixed boundary equilibria

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2024年第11期26卷 65-70页

作者： Ricardo FAReNGO Pablo l GARCÍA-MARTÍNeZ Hugo e FeRRARI Centro Atómico Bariloche Comisión Nacional de Energía AtómicaBariloche 8400Argentina Instituto Balseiro Universidad Nacional de CuyoBariloche 8400Argentina CONICeT CCT-Patagonia Norte Bariloche 8400Argentina

A simple and fast method to calculate the coil currents and the external poloidal flux and magnetic field consistent with a given internal magnetohydrodynamic(MHD) equilibrium and coil geometry is presented. The constrained optimization technique employed allows to fix the exact position of the X-points. The external poloidal flux and field are calculated using Green's functions expressed in terms of elliptic integrals that are calculated using a fast and accurate *** calculation can be limited to the region between the plasma and the device wall. An example for a double null configuration is presented.

关键词： MHD equilibrium Green's functions tokamak

Simplified seismic scenario analysis of existing masonry buildings accounting for local site effects

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil engineering 2024年第2期18卷 309-318页

作者： Ayşe e.ÖZSOYÖZBAY Işıl SANRI KARAPINAR Zehra N.KUTlU İsmail e.KIlIÇ Department of Civil engineering Maltepe UniversityIstanbul 34857Turkey School of engineering and Construction Oryx Universal CollegeDoha 12253Qatar

This study discusses the effects of local sites and hazard amplification on the seismic vulnerability assessment of existing masonry *** this context,a rapid seismic evaluation procedure was implemented on an old masonry building stock in the historical center Galata,located inİstanbul,to determine the seismic risk priority of the built *** scenarios were generated for all soil classes,different moment magnitudes,and source-to-site distances to obtain more accurate results for the seismic vulnerability assessment of the studied building ***,damage distributions estimated under nine different scenarios with/without site effects were compared and illustrated in maps to discuss changes in vulnerability owing to amplification *** this study,by re-examining the rapid seismic evaluation procedure by including geo-hazard-based assessment,the importance of site effects on the vulnerability and risk assessment of built heritage was *** proposed framework integrating field data and local site effects is believed to advance the current applications for vulnerability assessment of masonry buildings and provide an improvement in the application of rapid seismic assessment procedures with more reliable results.

关键词： masonry buildings seismic vulnerability assessment cultural heritage local site effect

Numerical studies towards practical large-eddy simulation

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 Thermal Science 2007年第4期16卷 328-336页

作者： J.Boudet J.Caro l.Shao e.lév(?)que lMFA laboratoire

large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria： numerical qualities （precision and spectral characteristics）, and adaptability to complex configurations. First, methods are tested on academic test-cases, in order to abridge with fundamental studies. Consistent results are obtained using adaptable finite volume method, with higher order advection fluxes, implicit grid filtering and ＂low-cost＂ shear-improved Smagorinsky model. This analysis particularly focuses on mean flow, fluctuations, two-point correlations and spectra. Moreover, it is shown that exponential averaging is a promising tool for leS implementation in complex geometry with deterministic unsteadiness. Finally, adaptability of the method is demonstrated by application to a configuration representative of blade-tip clearance flow in a turbomachine.

关键词： leS adaptable methods validation

Downscaling future climate scenarios to fine scales for hydrologic and ecological modeling and analysis

在线全文

学校读者我要写书评

暂无评论

ecological Processes 2012年第1期1卷 109-123页

作者： lorraine e Flint Alan l Flint U.S.Geological Survey Placer Hall6000 J St.SacramentoCA 95819USA

Introduction:evaluating the environmental impacts of climate change on water resources and biological components of the landscape is an integral part of hydrologic and ecological investigations,and the resultant land and resource management in the twenty-first *** of both climate and simulated hydrologic parameters on ecological processes are relevant at scales that reflect the heterogeneity and complexity of *** present,simulations of climate change available from global climate models[GCMs]require downscaling for hydrologic or ecological ***:Using statistically downscaled future climate projections developed using constructed analogues,a methodology was developed to further downscale the projections spatially using a gradient-inverse-distancesquared approach for application to hydrologic modeling at 270-m spatial ***:This paper illustrates a methodology to downscale and bias-correct national GCMs to subkilometer scales that are applicable to fine-scale environmental *** scenarios were chosen to bracket the range of future emissions put forth by the Intergovernmental Panel on Climate ***-scale applications of downscaled datasets of ecological and hydrologic correlations to variation in climate are ***:The methodology,which includes a sequence of rigorous analyses and calculations,is intended to reduce the addition of uncertainty to the climate data as a result of the downscaling while providing the fine-scale climate information necessary for ecological *** results in new but consistent data sets for the US at 4 km,the southwest US at 270 m,and California at 90 m and illustrates the utility of fine-scale downscaling to analyses of ecological processes influenced by topographic complexity.

关键词： downscaling climate change spatial scale scenarios

Advancements and challenges in treating advanced gastric cancer in the West

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 Gastrointestinal Oncology 2019年第9期11卷 652-664页

作者： Jennifer l leiting Travis e Grotz Division of Hepatobiliary and Pancreas Surgery Mayo Clinic

Gastric cancer is a leading cause of cancer incidence and death *** with advanced gastric cancer benefit from a multi-modality treatment *** oncologic resection with negative margins and complete lymphadenectomy plays a crucial role in long-term survival for patients with resectable *** utilization of minimally invasive techniques for gastric cancer has been slowly increasing and is proving to be both technically and oncologically *** chemotherapy is the current standard of care for advanced gastric cancer.A variety of chemotherapy regimens have been used with the combination of docetaxel,oxaliplatin,5-fluorouracil,and leucovorin being the current recommendation given its superior ability to induce a complete pathologic response and prolong *** use of radiation has been more controversial with its optimal place in the treatment sequence being *** are current ongoing studies assessing the impact of radiation as an adjunct or in place of *** treatments(e.g.,trastuzumab for human epidermal growth factor receptor 2 positive tumors and pembrolizumab for programmed death-ligand 1 positive tumors)are showing promise and are part of a continued emphasis on individualized *** chemotherapy may also play a role in preventing peritoneal recurrences for patients with high risk *** treatment of patients with advanced gastric cancer in the West continues to advance and improve with a better understanding of optimal treatment sequences and the utilization of personalized treatment regimens.

关键词： Gastric cancer D2 lymphadenectomy Minimally invasive surgery Neoadjuvant chemotherapy Chemoradiation Targeted treatments

Opposite Interplay Between the Canonical WNT/β-Catenin Pathway and PPAR Gamma： A Potential Therapeutic Target in Gliomas

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2018年第3期34卷 573-588页

作者： AlexANDre Vallée Yves lecarpentier Rémy Guillevin Jean-Noёl Vallée laboratory of Mathematics and Applications Unites Mixtes de Recherche (UMR) Centre National de la Recherche Scientifique (CNRS) 7348 University of Poitiers PoitiersFrance Delegation a la Recherche Clinique et a l'Innovation (DRCI) Hopital Foch Suresnes France Centre de Recherche Clinique Grand Hopital de l'EstFrancilien Meaux France DACTIM UMR CNRS 7348 University of Poitiers et CHU de Poitiers Poitiers France CHU Amiens Picardie University of Picardie Jules VerneAmiens France

In gliomas, the canonical Wingless/Int（WNT）/b-catenin pathway is increased while peroxisome proliferator-activated receptor gamma（PPAR-c） is *** two systems act in an opposite manner. This review focuses on the interplay between WNT/b-catenin signaling and PPAR-c and their metabolic implications as potential therapeutic target in gliomas. Activation of the WNT/bcatenin pathway stimulates the transcription of genes involved in proliferation, invasion, nucleotide synthesis,tumor growth, and angiogenesis. Activation of PPAR-c agonists inhibits various signaling pathways such as the JAK/STAT, WNT/b-catenin, and PI3 K/Akt pathways,which reduces tumor growth, cell proliferation, cell invasiveness, and angiogenesis. Nonsteroidal anti-inflammatory drugs, curcumin, antipsychotic drugs, adiponectin,and sulforaphane downregulate the WNT/b-catenin pathway through the upregulation of PPAR-c and thus appear to provide an interesting therapeutic approach for ***（TMZ） is an antiangiogenic agent. The downstream action of this opposite interplay may explain the TMZ-resistance often reported in gliomas.

关键词： WNT/beta-catenin pathway PPAR gamma Glioma STAT3 pathway PI3K/Akt pathway NSAID Curcumin