检索结果-南通市图书馆

electrochemical and Mass Loss Investigations of new Schiff Base as Corrosion Inhibitor for Mild Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2014年第1期21卷 121-124页

作者： M.Behpour n.Mohammadi e.Alian Department of Analytical Chemistry Faculty of ChemistryUniversity of Kashan

Corrosion inhibition effect of a new compound on mild steel in 6 mol/L HC1 medium was investigated by electrochemical impedance spectroscopy, Tafel polarization and mass loss methods. The results of mass loss and electrochemical methods indicated inhibition efficiency increase with increasing in inhibitor concentration. Polarization investigation revealed that inhibitor is mixed type inhibitor. The results of nyquist plots were analyzed through ap- propriate equivalent circuit model. The thermodynamic parameters showed chemisorption-physisorption of inhibitor on mild steel surface in acid media.

关键词： mild steel impedance spectroscopy polarization corrosion mass loss

effect of age on quality of fresh and frozen-thawed semenin White Italian ganders

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2003年第2期5卷 89-93页

作者： e.Lukaszewicz W.Kruszynski n.Fujihara Department of Poultry Breeding Department of Genetics and Animal Breeding Agricultural University of Wroclaw 51-630 Wroclaw PolandFukuoka Women's Junior College 6-16-4 Wakagidai Fukuma Fukuoka 811-3221 Japan

Aim: To comparatively evaluate the fresh semen quality of 1, 2 and 3-yr-old White Italian ganders (Anser anser L.) and the susceptibility of spermatozoa to freezing-thawing procedure. Methods: Semen was collected by dorso-abdominal massage every 2 days^3 days from three groups of ganders: 1-yr-old (n=11), 2-yr-old (n=7) and 3-yr-old (n=9). In the pooled fresh semen samples, the following parameters were evaluated: the ejaculate volume, the blood or fecal contamination and the motility, concentration and morphology of spermatozoa. Sperm motility and morphology were evaluated in the frozen-thawed semen. Semen diluted with eK extender was frozen in straws in a computerized freezing unit with 6 % dimethyl-formamide to -140 癈 at a rate 60 癈/min and then transferred into the Ln2 container. Straws with semen were thawed in a water bath at 60 癈. Results: The ejaculate volume decreased with the age (0.21 mL for 1-yr-old, 0.18 mL for 2-yr-old and 0.14 mL for 3-yr-old ganders); the sperm concentration increased with the age (327xl06mL-1 for 1-yr-old, 431xl06mL-1 for 2-yr-old and 547xl06mL-1 for 3-yr-old ganders); the number of live - normal sperm was significantly (Per in the 1-yr-old than that in the 2- and 3-yr-old ganders (26.61 %, 41.54 %and 35.9 %, respectively). The percentage of normal cells survived the freezing-thawing process was 37.7 %, 43.3 % and 40.9 % for 1-, 2- and 3-yr-old ganders, respectively. Conclusion: Freezing and thawing processes more significantly (Pected the motility, viability and morphology of spermatozoa in semen of 1-yr-old ganders in comparison with older males.

关键词： poultry gander age semen sperm morphology freezing

Delay Dependent Robust Stability of Singular Systems with Additive Time-varying Delays

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2013年第1期10卷 85-90页

作者： n. Chaibi e. H. Tissir A. Hmamed Laboratory of electronics Signals Systems and Data Processing (LESSI) Department of Physics Faculty of Sciences Dhar El Mahraz University Sidi Mohammed Ben Abellah

This paper considers the problem of delay-dependent robust stability for uncertain singular systems with additive time-varying delays. The purpose of the robust stability problem is to give conditions such that the uncertain singular system is regular, impulse free, and stable for all admissible uncertainties. The results are expressed in terms of linear matrix inequalities （LMIs）. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed method.

关键词： Singular systems additive time-varying delays linear matrix inequalities (LMIs) robust stability delay-dependent conditions

Transverse Transport of Polymeric nanofluid under Pure Internal Heating: Keller Box Algorithm

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2018年第7期69卷 106-118页

作者： R.Mehmood S.Rana e.n.Maraj Department of Mathematics Faculty of Natural Sciences HITEC University

The present work aims to investigate transverse Oldroyd-B nanofluid flow on a stretched panel with consideration of internal heat generation. Buongiorno model is utilized to study influence of thermophoresis and Brownian motion effects. A numerical procedure known as Keller box algorithm is used to solve the governed physical *** velocity, temperature and concentration of nanoparticles are expressed. Also, concerned physical measures such as heat and mass transfer are investigated numerically. The simulations performed revealed that fluid parameters play a significant role in heat transfer under Brownian motion and thermophoresis effects. Local heat flux is elevated while local mass flux is suppressed with enhancing Brownian motion parameter. Streamlines pattern exhibits that flow is more inclined in the presence of Deborah number effects. To the best of our knowledge, transverse flow of an Oldroyd-B type fluid which incorporates the thermal relaxation effects has never been reported before in the presence of Brownian motion and internal heating phenomenon. Therefore we intend to discuss these features in detail. The obtained results are a novel contribution, which can be benchmark for further relevant academic research related to polymer industry.

关键词： transverse flow nanofluid Oldroyd-B internal heating

STUDY On THe PROPeRTIeS OF BLenD OF nATURAL RUBBeR LATeX/MeTHYL MeTHACRYLATe GRAFTeD RUBBeR LATeX BY GAMMA RADIATIOn

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2007年第5期25卷 519-523页

作者： n.C. Dafader M.e. Haque F. Akhtar nuclear and Radiation Chemistry Division Institute of Nuclear Science ＆ Technology Bangladesh Atomic Energy Commission P. O. Box 3787 Dhaka Bangladesh

natural rubber latex （nRL） and methyl methacrylate （MMA） grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The tensile properties, swelling ratio and permanent set were measured. The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy. Modulus increases from 6.99 MPa to 9.87 MPa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose. elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends. The decreasing trend of permanent set is high up to 5 kGy absorbed dose, and beyond that dose, it becomes almost flat.

关键词： natural rubber latex MMA grafted rubber latex Blend rubber Irradiation Cross-link.

Free Oxide Distribution in Poorly and Well Drained Soils Developed on Calcareous Alluvial Deposits

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2003年第4期13卷 345-351页

作者： n. K. MOUSTAKAS P. e. BAROUCHAS Agricultural University of Athens Laboratory of Soil Science and Agricultural Chemistry 75 /era Odos Botanikos 11855Agricultural University of Athens Laboratory of Soil Science and Agricultural Chemistry 75 /era Odos Botanikos 11855

A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained soils and from two poorly drained soils, classified as Alfisols, were collected and used in this study. After certification of soil homogeneity the acid ammonium oxalate and dithionite-citrate-bicarbonate methods were used to extract free iron and manganese oxides from the samples. Iron oxides extracted by the dithionite-citrate-bicarbonate method (Fed) were significantly higher than the iron oxides extracted by the ammonium oxalate method (Feo), indicating that a considerable fraction is present in crystalline forms,independent of drainage status. A confirmation of free iron oxides and fine clay was detected. The ratios Feo/Fed and (Fed-Feo)/total Fe (Fet) could not be used to distinguish the well drained soils from the poorly drained soils. Manganese movement in a soluble form is independent of the fine clay.

关键词： argillic horizon calcareous alluvial deposits iron oxides manganeseoxides soil homogeneity

Impact of Internal Heat Source on Mixed Convective Transverse Transport of Viscoplastic Material under Viscosity Variation

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2018年第10期70卷 423-429页

作者： R.Tabassum R.Mehmood e.n.Maraj Department of Mathematics Faculty of Basic and Applied Sciences Air UniversityIslamabad Pakistan Department of Mathematics Faculty of Natural Sciences HITEC UniversityTaxila Cantt Pakistan

This communication addresses the impact of heat source/sink along with mixed convection on oblique flow of Casson fluid having variable viscosity. Similarity analysis has been utilized to model governing equations, which are simplified to set of nonlinear differential equations. Computational procedure of shooting algorithm along with 4 th order Range-Kutta-Fehlberg scheme is opted to attain the velocity and temperature distributions. Impact of imperative parameters on Casson fluid flow, temperature, significant physical quantities such as skin friction, local heat flux and streamlines are displayed via graphs.

关键词： oblique stagnation point flow variable viscosity partial slip mix convection heat generation/absorption Runge-Kutta Fehlberg scheme

Heavy metal concentrations in soils and plants in the vicinity of Arufu lead-zinc mine, Middle Benue Trough, nigeria

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2010年第2期29卷 167-174页

作者： nganje T.n. Adamu C.I. Ukpong e.e. Department of Geology University of Calabar Formerly Department of Geology University of Calabar

This study focused on the influence of base metal mining on heavy metal levels in soils and plants in the vicinity of Arufu lead-zinc mine, nigeria. Soil samples (0-15 cm depth) and plant samples were collected from cul-tivated farmlands in and around the mine, the unmineralized site and a nearby forest (the control site). The samples were analyzed for heavy metals (Fe, Zn, Mn, Cu, Pb, Cr and Cd) by Atomic Absorption Spectrophotometry (AAS). The physical properties of soils (pH and LOI) were also measured. Results showed that soils from cultivated farm-lands have neutral pH values (6.5-7.5), and low organic matter contents (evels of Zn, Pb and Cd in culti-vated soils were higher than the concentrations obtained from the control site. These heavy metals are most probably sourced from mining and agricultural activities in the study area. Heavy metal concentrations measured in plant parts decreased in the order of rice leaves>cassava tubers>peelings. In the same plant species, metal levels decreased in the order of Zn>Fe>Mn>Cu>Pb>Cr>Cd. Most heavy metals were found in plant parts at average concentrations normally observed in plants grown in uncontaminated soil, however, elevated concentrations of Pb and Cd were found in a few cassava samples close to the mine dump. A stepwise linear regression analysis identified soil metal contents, pH and LOI as some of the factors influencing soil-plant metal uptake.

关键词：土壤重金属含量土壤样品植物样本铅锌矿尼日利亚原子吸收光谱法线性回归分析 amp

The Japanese ladybirds, Coccinula crotchi and Coccinula sinensis, are infected with very closely related strains of male-killing Flavobacterium

在线全文

学校读者我要写书评

暂无评论

Insect Science 2014年第6期21卷 699-706页

作者： Sherif elnagdy Susan Messing Michael e. n. Majerus Department of Genetics University of Cambridge Downing Street Cambridge CB2 3EH UK Botany Department Faculty of Science Cairo University Giza Egypt University of Rochester Rochester New York USA Department of Biostatistics and Computational Biology University of Rochester Rochester New York USA

Male-killing is 1 of 4 known strategies that inherited parasitic endosymbionts have evolved to manipulate their host＇s reproduction. In early male-killing, infected male offspring are killed early in embryogenesis. Within the Insecta, male-killing bacteria have been found in a wide range of hosts. The Coccinellidae families of beetles, better known as ladybirds, are particularly prone to male-killer invasion. In samples of the coccinellid, Coc- cinula crotchi, from Japan, a new male-killing bacterium was revealed by phenotypic assay. Molecular genetic analysis revealed the identity to be a tetracycline-sensitive Flavobac- terium that causes female-biased offspring sex ratio. Furthermore, that Flavobacterium strain was found to be closely related to the Flavobacterium causing male-killing in the congeneric Japanese coccinellid, Coccinula sinensis, which was collected from the same region. However, we found slightly different Flavobacterium strains infecting C. sinen- sis from regions with different environmental conditions. This may be an indication of horizontal transmission of male-killing Flavobacterium between these 2 ladybird spices. Finally, environmental conditions may affect the spread of male-killing bacteria among their hosts.

关键词： Coccinula crotchi Coccinula sinensis endosymbionts Flavobacterium inherited bacteria male-killing sex ratio distorter