检索结果-南通市图书馆

Response of mollusk assemblages from the Luochuan loess section to orbital forcing since the last 250 ka

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

Chinese Science Bulletin 2000年第17期45卷 1617-1622页

作者： D.D.Rousseau laboratoire de Palynologie-URA 327 University Montpellier Ⅱ 34095 Montpellier France

This note presents a new result of terrestrial mollusk study from the Luochuan loesssection since the last 250 ka. A total of 213 samples, taken at intervals of 10 cm in the S0-L3 portion, were analyzed for fossil mollusks. Generally, 150-600 individuals were counted in each sample. According to the distribution of mollusk fossil assemblages in the loess section, 11 mollusk fossil zones have been recognized, representing different climatic and ecological conditions. Three main ecological groups were identified according to the temperature and moisture requirements of each taxon. The cold-aridiphilous group shows maxima at about 240-220, 190-182, 150-140 and 74 -66 ka BP. The thermo-humidiphilous set has high abundances for at least 6 times in the section at about 246-240, 220-216, 170-158, 92-86, 60-44 and 10 kaBP. Our results show that variations in mollusk ecological groups are related with changes in the Earth orbital parameters at the 41 and 20 ka frequencies. Maxima in thermo-humidiphilous taxa

关键词： mollusk assemblage loess orbital forcing.

Field-induced phase transitions in chiral smectic liquid crystals studied by the constant current method

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第5期25卷 373-379页

作者： H Dhaouadi R Zgueb O Riahi F Trabelsi T Othman departement de physiqu Faculte des Sciences de Tunis Laboratoire de physique de la matiere molle et de modelisation electromagnetique (LP3ME) Universite Tunis Elmanar Campus universitaire 2092 Tunis Tunisia

In ferroelectric liquid crystals, phase transitions can be induced by an electric field. The current constant method allows these transition to be quickly localized and thus the（E, T） phase diagram of the studied product can be *** this work, we make a slight modification to the measurement principles based on this method. This modification allows the characteristic parameters of ferroelectric liquid crystal to be quantitatively measured. The use of a current square signal highlights a phenomenon of ferroelectric hysteresis with remnant polarization at null field, which points out an effect of memory in this compound.

关键词： chiral smectic liquid crystal constant current method ferroelectric polarization dielectric permittivity

Kinetic degradation of amoxicillin by using the electro-Fenton process in the presence of a graphite rods from used batteries

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2021年第4期34卷 183-190页

作者： Hakima Kadji Idris Yahiaoui Zehira Garti Abdeltif Amrane Farida Aissani-Benissad laboratoire de Genie de l'Environnement(LGE) Faculte de TechnologieUniversite de Bejaia06000 BejaiaAlgeria Ecole Nationale Superieure de Chimie de Rennes Universite RenneslCNRSUMR 622611 allee de BeaulieuCS 50837France

This study reports the removal of amoxicillin(AMX)in aqueous media using the electroFenton process in the presence of a graphite cathode recovered from used *** impact of the relevant parameters on the electroFenton process,namely the applied current intensity,the temperature,the initial concentration of AMX and the initial concentration of ferrous ions were *** results showed that the optimal values were:I=600 mA,T=25℃,[AMX]_(0)=0.082 mmol·L^( 1) and[Fe^(2+)]=1 mmol·L^(1),leading to 95%degradation and 74%*** model parameters of AMX mineralization were determined using nonlinear methods,showing that it follows a pseudosecondorder *** Energy consumption(EC)calculated under the optimal values was found to be 0.79 kWhg 1,which was of the same order of magnitude of those reported in other findings;while it is noteworthy that the electrodes used in our study are of a lower cost.

关键词： Wastewater Amoxicillin Electro-Fenton Pharmaceuticals Solid waste recovery Kinetic modelling

Numerical study of the performance of multistage Scaba 6SRGT impellers for the agitation of yield stress fluids in cylindrical tanks

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2015年第3期27卷 436-442页

作者： AMEUR Houari BOUZIT Mohamed GHENAIM Abdellah laboratoire de Mécanique Appliquée Faculté de Génie MécaniqueUSTO-MB Institut de Technologie Université Ibn Khaldoun INSA de Strasbourg-24 Bd de la Victoire-67084 Strasbourg-France

The 3-D flow fields and power consumption in a vessel stirred by multistage Scaba 6SRGT impeller have been investiga- ted. The Xanthan gum solutions in water were used, which have a shear thinning behavior with yield stress. This study was carried out with the help of a CFD package （CFX 13.0, Ansys Inc.） which is based on the finite volume method to solve the momentum equations. The effects of stirring rate, fluid rheology, impeller number, impeller location and vessel size on the performance of such stirred system are presented. To validate the CFD model, our predicted results have been compared with other literature data and a satisfactory agreement has been found.

关键词： Scaba 6SRGT impeller multistage agitator yield stress fluid stirred tank power consumption

Numerical studies towards practical large-eddy simulation

在线全文

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

Self-organization and tunable characteristic lengths of twodimensional hexagonal superlattices of nanowires directly grown on substrates

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第1期16卷 1606-1613页

作者： D.Yi L.Peres A.Pierrot S.Cayez R.Cours B.Warot-Fonrose C.Marcelot P.Roblin K.Soulantica T.Blon Universitéde Toulouse Laboratoire de Physique et Chimie des Nano-ObjetsUMR 5215 INSACNRSUPS135 Avenue de RangueilF-31077 Toulousecedex 4France CEMES Universitéde ToulouseCNRS29 Rue Jeanne MarvigBP 94347F-31055 ToulouseFrance laboratoire de Génie Chimique Universitéde ToulouseCNRSINPUPS ToulouseFrance

The organization of nano-objects on macroscopic surfaces is a key challenge for the technological improvement and implementation of *** achieving operational functions,it is required to assemble nano-objects as controllable building blocks in highly ordered ***,we demonstrate the growth and self-organization of metallic nanowires on surfaces into hexagonal superlattices with tunable characteristic lengths depending of the stabilizing surfactants *** from a reacting mixture containing a Pt(111)substrate,a Co organometallic precursor,an amine,and an acid dissolved in a solvent,we quantify the structural evolution of superlattices of vertical single-crystalline Co nanowires on Pt,using a combined analysis of small angle neutron scattering,transmission,and scanning electron *** show the concerted steps of a spontaneous growth and self-organization of the nanowires into two-dimensional(2D)hexagonal lattice on Pt,at intervals starting from a few hours of reaction to a highly ordered superlattice at longer ***,it is shown that apart from long-chain acid and long-chain aliphatic amine pairs used as stabilizers,the combination of a long-chain aliphatic and a short-chain aromatic ligand in the synthesis can also be employed for the nanowire superlattices ***,the possibility to employ different pairs allows quantitative modulation of the nanowire arrays,such as the interwire distance and the packing fraction.

关键词： metallic nanowire array self-assembly self-organized growth Co nanowire anisotropic growth solution epitaxial growth

Protective behaviors regarding coastal flooding risk in a context of climate change

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

Advances in Climate Change Research 2020年第4期11卷 310-316页

作者： Colin LEMEE Oscar NAVARRO Diego RESTREPO-OCHOA denis MERCIER Ghozlane FLEURY-BAHI University of Brest Brest29200France laboratoire de Psychologie des Pays de La Loire University of NantesNantes44312France CES University Medellin050022Colombia laboratoire de Geographie Physique(UMR 8591-CNRS) Sorbonne UniversiteParis75000France

The physical vulnerability of coastal areas due to rising sea level and the flooding risk consequent,does not guarantee the implementation of protective behaviors by these risk zones’*** study aims to establish the link between the willingness to carry out protective behaviors and physical and perceived indicators of vulnerability.A typology of coastal flooding vulnerability,uses various physical indicators and their perceived counterparts which have been collected from 490 inhabitants of Cartagena(Colombia,declared world heritage of humanity by UNESCO in 1984),resident in areas of coastal flooding *** item-response theory(IRT)approach has been *** results reveal that the implementation of protective behaviors is more related to perceived indicators,such as distance to the sea,than to actual physical *** observe that physical vulnerability is linked to the intention to carry out protective *** presence of a defensive structure against coastal flooding could be considered as a visual cue and be a good predictor of the willingness to carry out protective *** the contrary,people in the most vulnerable situation(single-storey house)do not demonstrate a higher level of willingness to carry out protective behavior,as well of participants who lived in residential buildings which have demonstrated lower level of willingness to carry out such ***,vulnerability of the house is not seen as a criterion that encourages participants to better protect themselves.

关键词： Coastal flooding risk Protective behaviors Climate change Vulnerability Item response theory

SYNTHESIS OF SOLUBLE POLY(3,4-DIHYDROXY-o-TOLYLENE):REDOX POLYMER

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

Chinese Journal of Polymer Science 2006年第1期24卷 41-46页

作者： Sad Moulay Fatima M'zyène laboratoire de Chimie-Physique Moléculaire et Macromoléculaire Faculté des Sciences de l'Ingénieur Département de Chimie Industrielle Université de BlidaRoute de SoumèaB.P.270Blida 09000Algeria. laboratoire de Chimie-Physique Moléculaire et Macromoléculaire Faculté des Sciences de l'Ingénieur Département de Chimie Industrielle Université de BlidaRoute de SoumaB.P.270Blida 09000Algeria.

Conventional chloromethylation, paraformaldehyde/hydrogen chloride in acetic acid medium, was applied to 1,2- dimethoxybenzene. Chloroform-soluble poly（3,4-dimethoxy-o-tolylene） was obtained with an intrinsic viscosity of 0.034 dL g^-1. The polymer was evaluated as a condensation redox polymer precursor formed by a Friedel-Crafts reaction. Cleavage of the methoxy groups present in this polymer resulted in poly（3,4-dihydroxy-o-tolylene） which manifested a great air-oxidation resistance. The redox property of the latter polymer was found to be 1017 mV by potentiometric titration with 0.05 N ceric ammonium nitrate at 25℃. This midpotential was compared to that of catechol, a monomeric analogue, under the same titration conditions.

关键词： Poly(3,4-dimethoxy-o-tolylene) Poly(3,4-dihydroxy-o-tolylene) Redox polymer.

Evaluation of androgenic activity of Zingiber officinale and Pentadiplandra brazzeana in male rats

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2002年第4期4卷 299-301页

作者： PierreKamtchouing GisèleYolandeMbongueFandio ThéophileDimo Hermine Boukeng Jatsa laboratoire de Physiologie Animale Faculté des Sciences Université de Yaoundé I B.P.812 Yaoundé CamerounLaboratoire de Physiologie Animale Faculté des Sciences Université de Yaoundé I B.P.812 Yaoundé CamerounLaboratoire de Physiologie Animale Faculté des Sciences Université de Yaoundé I B.P.812 Yaoundé CamerounDépartement de Biologie et de Physiologie Animales Faculté des Sciences Université de Douala B.P. 24157 Douala Cameroun

Aim: Aqueous extracts of Zingiber officinale and Pentadiplandra brazzeana were tested for their possible androgenic activity in male Wistar rats. Methods: The aqueous extracts of the two plants were gavaged separately to 2 groups of rats at a similar dose of 600 ***^***-1 for 8 days. At the end of the treatment, the animals were killed and the blood, testis, epididymis, seminal vesicles and prostate were collected for biochemical analysis. Results: The aqueous extract of Z. officinale significantly increased in the relative weight of the testis, the serum testosterone level, testicular cholesterol level and epididymal α-glucosidase activity. The aqueous extract of P. brazzeana significantly increased the weights of the testis, seminal vesicles and prostate. It also significantly increased the serum and testicular testosterone level. The fructose, α-glucosidase and cholesterol levels in P. brazzeanatreated rats were increased by 28%, 35% and 114%, respectively. Conclusion: The aqueous extracts of both P. brazzeana and Z. officinale have an androgenic activity, which seems to be more potent with P. brazzeana than with Z. officinale. (Asian J Androl 2002 dec; 4: 299-301)

关键词： P. brazzeana Z. officinale testosterone androgenic activity