检索结果-南通市图书馆

Ecogeomorphic Feedbacks in Semiarid Rangelands:A Review

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2009年第2期19卷 217-229页

作者： I.STAVI H.LAVEE E.d.UNGAR P.SARAH Laboratory of Soil and Geomorphology Department of Geography and EnvironmentBar Ilan UniversityRamat Gan 52900(Israel) department of Agronomy and Natural Resources Institute of Plant SciencesAgricultural Research Organizationthe Volcani CenterBet Dagan 50250(Israel)

The ecogeomorphic processes occurring on semiarid rangelands are reviewed, with emphasis on the source-sink relations and positive feedback loops that existed between shrub patches and intershrub areas, and the way livestock presence affected these interactions. Compared with intershrub areas, the shrub patches had a higher soil porosity, infiltration capacity, water-holding capacity, hydraulic conductivity, structural stability, and organic matter content, and lower bulk density. These differences derived from a host of processes whose intensity was less in the shrub patches, including raindrop impact, mechanical crust formation, overland water flow, soil erosion, evaporative moisture loss, and flock trampling. There was also greater shading of the soil surface; soil and litter deposition; water accumulation; microbial, fungal, and mesofaunal activities in the shrub patches. The overland flow of water carried soil and litter from the intershrub areas to the shrub patches and resulted in microtopographic modifications that tended to strengthen these source-sink relations. Grazing had an impact on these processes, not only at the shrub-intershrub scale but also within the intershrub areas, through the creation of highly compacted trampling routes. The combined role of the above ecogeomorphic processes was to maintain the rangeland＇s functionality. without these inter-relationships, water loss, soil erosion, and nutrient depletion would occur at the hillside scale, causing degradation of the landscape.

关键词： intershrub areas shrubs soil resources trampling routes

Experimental study on fly ash capture mercury in flue gas

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2010年第4期53卷 976-983页

作者： Mercedes díAZ-SOMOANO Patricia ABAd-VALLE M.Rosa MARTíNEZ-TARAZONA Instituto Nacional del Carbón(CSIC)

Systematic experiments were conducted on a fixed-bed reactor to investigate the interaction between fly ash and mercury,the results implied that fly ash can capture mercury *** different fly ashes,the unburned carbon in the FA2 and FA3 fly ashes has the highest mercury capture capacity,up to 10.3 and 9.36 μg/g,respectively,which is close to that of commercial activated *** is no obvious relationship between mercury content and carbon content or BET surface area of fly *** classification standard was applied to distinguish fly ash carbon *** content is not the only variable that controls mercury capture on fly ash,there are likely significant differences in the mercury capture capacities of the various carbon *** capture capacity mainly depends on the content of anisotropy carbon particles with porous network structure.

关键词： mercury fly ash unburned carbon petrography adsorption

BARYON dECAY PARAMETERS

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2016年第10期40卷 807-808页

作者： E.d. Commins University of California Berkeley

Baryon semileptonic decays The typical spin-1/2 baryon semileptonic decay is described by a matrix element, the hadronic part of which may be written as：

关键词：

Agricultural impacts of longwall mine subsidence:the experience in Illinois,USA and Queensland,Australia

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

International Journal of Coal Science & Technology 2014年第2期1卷 207-212页

作者： Robert G.darmody R.Bauer d.Barkley S.Clarke d.Hamilton Land Reclamation division Illinois Natural Resources DepartmentIllinois Prairie Research InstituteUniversity of IllinoisChampaignUSA Bandanna Energy Limited and Agricultural Coexistence Research Committee BrisbaneAustralia

Unlike conventional room and pillar underground coal mining,where subsidence is designed to be prevented,subsidence is a planned outcome of other *** include high extraction retreat,where the roof supporting pillars are systematically removed,and longwall mining,which employs a machine that mines a continuous strip of coal,thus leaving no roof *** types result in the surface dropping -70% of the mined-out *** Illinois there was a concern that farm land thus subsided would be lost to productive ***,the possibility that planned mine subsidence would be banned in Illinois lead to the creation of the Illinois Mine Subsidence Research Program in 1985 to investigate agricultural impacts of planned mine subsidence and the possibility of mitigating its *** findings established that subsidence was not as detrimental as feared and that the impacts could be *** project was a successful collaboration of state and federal governments and local ***,in Queensland,longwall mining is opposed by some in the farming *** response,Bandanna Energy,the company planning the mining,organized the Agricultural Coexistence Research Committee to oversee research into the mitigation of longwall mining *** the soils,climate,and regulatory regimes are different,concerns of the local communities are similar.

关键词： Agricultural impact Longwall mine subsidence Coal mining subsidence Subsidence mitigation

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

Foreword

Chinese Journal of Oceanology and Limnology 2004年第3期22卷 J001-J002页

作者： d.X.HU

Ocean circulation in the Yellow and East China Seas is very rich in mesoscale phenomena, such as eddies, fronts, upwellings, river plumes, etc. Among others, having drawn tremendous attention from oceanographic community in the past for nearly 50years are mainly the Yellow Sea Cold water Mass(YSCwM) and its related circulation, the Yellow Sea warm Current (YSwC), the East China Sea Cold Eddy (ECSCE), the Taiwan warm Current(TwC) and the Changjiang (Yangtze River) diluted water (Cdw).

关键词：数字模型波浪潮汐环流黄海东海

Mechanistic study of substrate-based galvanic replacement reactions

在线全文

学校读者我要写书评

暂无评论

Nano Research 2014年第3期7卷 365-379页

作者： Kyle d. Gilroy Aarthi Sundar Pouyan Farzinpour Robert A. Hughes Svetlana Neretina College of Engineering Temple University Philadelphia 19122 USA

The sacrificial templates used in galvanic replacement reactions dictate the properties of the hollow metal nanostructures formed. Here, we demonstrate that substrate-based Au-Ag nanoshells with radically altered properties are obtained by merely coating silver templates with an ultrathin layer of gold prior to their insertion into the reaction vessel. The so-formed nanoshells exhibit much smoother surfaces, a higher degree of crystallinity and are far more robust. dealloying the nanoshells results in the first demonstration of substrate-based nanocages. Such cages exhibit a well-defined pattern of geometric openings in directions corresponding to the {111}-facets of the starting template material. The ability to engineer the cage geometry through adjustments to the orientational relationship between the crystal structure of the starting template and that of underlying substrate is demonstrated. Together these discoveries provide the framework to advance our understanding of the mechanisms governing substrate- based galvanic replacement reactions.

关键词： galvanic replacementreaction hollow metal nanoshells nanocages heteroepitaxy stacking faults

Ni-based catalysts obtained from perovskites oxides for ethanol steam reforming

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

燃料化学学报 2018年第11期46卷 1332-1341页

作者： Fabiola Nerina Agüero Jose Antonio Alonso Maria Teresa Fernández-díaz Luis Eduardo Cadus Instituto de Investigaciones en Tecnología Química(INTEQUI) UNSL-CONICETAlmirante Brown 14555700 San LuisArgentina Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones CientíficasCantoblanco28049 MadridSpain Institut Laue-Langevin B.P.156F-38042 Grenoble Cedex 9France

Perovskites as host structures of cations were used in order to generate in situ active and stable catalysts for ethanol steam reforming. For this purpose,La_(1-x)Mg_xAl_(1-y)Ni_yO_3(x = 0.1; y = 0,0.1,0.2,0.3) perovskites were synthetized by the citrate *** segregation is evident for a substitution level higher than 0. 2. The segregation of Ni as NiO generated species interacts with different metal-support after the reduction step. The y = 0.1 catalyst presents the highest H_2 yield value about 85% during reaction time,with low mean values of CH_4 and CO selectivities of 3.4% and 11%,respectively and a low carbon formation. The better performance of y = 0.1 catalyst could be attributed to the minor proportion of segregated phases,thus a controlled expulsion of Ni is successfully reached.

关键词： perovskites catalyst design ethanol steam reforming

Preparation and hydrogen storage properties of nanocrystalline TiFe synthesized by mechanical alloying

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2017年第1期27卷 149-155页

作者： V.Yu.Zadorozhnyy G.S.Milovzorov S.N.Klyamkin M.Yu.Zadorozhnyy d.V.Strugova M.V.Gorshenkov S.d.Kaloshkin National University of Science and Technology “MISIS” department of Chemistry M.V. Lomonosov Moscow State University

In this research, the mechanism of mechanical alloying（MA） synthesis of TiFe intermetallic compound（IMC）from individual components Ti and Fe has been studied. The partition coefficient of the apparent diffusion and the reaction rate constant during MA solid-state synthesis of the TiFe intermetallic compound in a planetary ball mill have been estimated. The results indicate that the apparent diffusion coefficient is close to 10;cm;/s that is approximately one order higher than the conventional high temperature diffusion coefficient. The reaction rate constant is close to 1.75·10;. The relation between the structure and the hydrogen storage properties of MA synthesized IMC TiFe have been briefly discussed.

关键词： Mechanical alloying Intermetallic compound TiFe Hydrogen storage Apparent diffusion coefficient Reaction rate constant

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

采用遗传学和生理学方法研究家禽福利育种

中国家禽 2010年第5期32卷 38-39页

作者： S.Avendano d.A.Emmerson w.M.Muir T.Nguyen w.J.Kuenzel A.Jurkevich P.B.Thompson 美国安伟捷公司美国普渡大学美国阿肯色州立大学美国密歇根州立大学

1遗传育种与家禽福利的关系腿畸形、骨骼缺陷、代谢失调等动物福利性状是育种工作者长期以来重点考虑的问题。这些问题由于其较低的遗传力以及与肉鸡生产性状的负相关性是育种工作的一大挑战。安伟捷公司自20世纪90年代早期就将福利性... 详细信息

1遗传育种与家禽福利的关系腿畸形、骨骼缺陷、代谢失调等动物福利性状是育种工作者长期以来重点考虑的问题。这些问题由于其较低的遗传力以及与肉鸡生产性状的负相关性是育种工作的一大挑战。安伟捷公司自20世纪90年代早期就将福利性状囊括在育种目标之内,在骨骼和代谢方面取得了较大的进展。将福

关键词：家禽禽类遗传学生理学基础医学