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meson-production experiments at COSY-Jülich

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Chinese Physics C 2010年第9期34卷 1263-1268页

作者： m.b.scher Institute für Kernphysik and Jülich Center for Hadron Physics

Selected results from experiments at COSY-Jülich are presented： an attempt to measure the mass of the η meson with high precision （ANKE facility）,first steps towards the detection of rare η decays （WASA）,and s... 详细信息

关键词： meson production

Alloy design by dislocation engineering

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Journal of materials Science & Technology 2018年第3期34卷 417-420页

作者： m.X.Huang b.b.He Department of mechanical Engineering The University of Hong Kong

Ultra-high strength alloys with good ductility are ideal materials for lightweight structural application in various industries. However, improving the strength of alloys frequently results in a reduction in ductility, which is known as the strength-ductility trade-off in metallic materials. Current alloy design strategies for improving the ductility of ultra-high strength alloys mainly focus on the selection of alloy composition （atomic length scale） or manipulating ultra-fine and nano-grained microstructure （grain length scale）. The intermediate length scale between atomic and grain scales is the dislocation length scale. A new alloy design concept based on such dislocation length scale, namely dislocation engineering, is illustrated in the present work. This dislocation engineering concept has been successfully substantiated by the design and fabrication of a deformed and partitioned （D＆P） steel with a yield strength of 2,2 GPa and an uniform elongation of 16%. In this D＆P steel, high dislocation density can not only increase strength but also improve ductility. High dislocation density is mainly responsible for the improved yield strength through dislocation forest hardening, whilst the improved ductility is achieved by the glide of intensive m.b.le dislocations and well-controlled transformation-induced plasticity （TRIP） effect, both of which are governed by the high dislocation density resulting from warm rolling and martensitic transformation during cold rolling. In addition, the present work proposes for the first time to apply such dislocation engineering concept to the quenching and partitioning （Q＆P） steel by incorporating a warm rolling process prior to the quenching step, with an aim to improve simultaneously the strength and ductility of the Q＆P steel. It is believed that dislocation engineering provides a new promising alloy design strategy for producing novel strong and ductile alloys.

关键词： Alioy design Dislocation engineering D&P steel Q&P steel TRIP Warm rolling

Soil: An Extreme Habitat for microorganisms?

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Pedosphere 2004年第2期14卷 137-144页

作者： m.b.LTER Institute for Polar Ecology University of Kiel Wischhofstr. 1-3 Bldg. 12 D-24148 Kiel (Germany)

The question is asked whether soils can be regarded as extreme environments with respect to microorganisms. After defining some extreme environments in a general sense, special properties of extreme environments are compared to soil habitats, with special emphasis laid on time frame and localities. In relation to water availability, nutrients and other properties, such places as aggregates can show properties of extreme habitats. These features, which can act at different levels of the system from the community level down to the cellular level, are summarized as stress factors. The latter,where many switches are located leading to different strategies of survival, is described as the most important one. This raises the question of how organisms have adapted to such conditions. The soil system demands a broad spectrum of adaptations and/or adjustments for a highly variable *** soil microorganisms'adaptation can thus be seen as the highest kind of flexibility and is more useful than any other special adaptation.

关键词：土壤环境微生物营养水分

Effect of Ion Concentrations on the Characteristics of a multi-Component magnetized Plasma Sheath

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Plasma Science and Technology 2009年第6期11卷 642-646页

作者： m.m.HATAmI b.SHOKRI Laser-Plasma Research Institute of Shahid beheshti University G.C.EvinTehranIran Physical Department and Laser-Plasma Research Institute of Shahid beheshti University G.C.EvinTehranIran

A hydrodynamic approach is used to investigate a three-component magnetized plasma sheath which consists of electrons and two species of positive ions. Assuming a phase space of one-dimensional spatial coordinate system and three-dimensional velocity coordinate system, the effect of different concentrations of positive ion species on some characteristics of the plasma sheath such as the velocity and density distribution of positive ion species and the electrostatic potential of this region is investigated. The calculated results show that the increase in the density ratio of positive ion species causes a decrease in both the ion velocities and the electrostatic potential of the sheath region. Also, it is shown that in the sheath region of a magnetized plasma consisting of only one positive ion species the bumps of the net density of charged particles disappears much faster. In addition, three-dimensional velocity of each positive ion species in the sheath region is plotted for different concentrations of positive ion species.

关键词： magnetized plasma plasma and electropositive plasma sheath hydrodynamic equations multi-component sheath

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美国教育改革的第三次浪潮

世界社会科学 1991年第9期 30-33页

作者： m.b.别利亚耶娃 ,由之

1990年2月,美国总统布什在发表国情咨文时强调,教育是行政当局优先考虑的工作之一,当局准备继续推行一系列学校改革。这场改革始于1983年发表的报告《处于危险中的国家》。这篇报告(致美国人民的公开信)是1983年由改进教育质量委员会发... 详细信息

1990年2月,美国总统布什在发表国情咨文时强调,教育是行政当局优先考虑的工作之一,当局准备继续推行一系列学校改革。这场改革始于1983年发表的报告《处于危险中的国家》。这篇报告(致美国人民的公开信)是1983年由改进教育质量委员会发表的,它使全国大为震惊。报告中第一次提出国家的未来及其存在的条件本身取决于它的公民的教育水平的问题。这篇报告以及后来几篇报告的作者一致认为,美国的中等教育

关键词：第三次浪潮美国美利坚合众国北美洲学校教学大纲移民家庭

Linear Precoder Design for Correlated Rician Fading Channel Under Imperfect CSI

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China Communications 2023年第9期20卷 160-170页

作者： S.b.m.Priya School of Electrical and Electronics Engineering SASTRA Deemed UniversityThanjavur 613401India

In this paper,we have modeled a linear precoder for indoor multiuser multiple input multiple output(mU-mImO)system with imperfect channel state information(CSI)at *** Rician channel is presumed to be mutually coupled and spatially,temporarily *** imperfection with CSI is primarily due to the channel estimation error at receiver and feedback delay amidst the receiver and transmitter in CSI *** with,the insufficient spacing between the antenna at transmitter and receiver persuades mutual coupling(mC)among the array *** addition,the mImO channel is presumed to be jointly correlated(Weichselberger correlation model).When we look back on the existing precoder design,it considered spatial correlation alone disregarding joint correlation of antenna array *** all above assumption,we have designed a linear precoder which minimizes mean squared error(mSE)subjected to total transmit power constraint for mUmImO *** simulation results proven that proposed precoder shows substantial enhancement in bit error rate(bER)performance in comparison with the existing *** mathematical analysis corroborates the simulation results.

关键词： channel estimation error feedback delay mmSE linear precoder mutual coupling spatial cor-relation Weichselberger correlation model

The Adsorption of Copper from Aqueous Solutions Using Acrylamide-Grafted Cellulose

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Journal of Environmental Science and Engineering 2010年第3期4卷 25-31页

作者： m.m. Shahri m.b. Ahmad m.J. Haron m.Z.A. Rahman Department of Chemistry Faculty of Science University Putra Malaysia UPM-Serdang 43400 Malaysia Centre for Academic Development University Putra Malaysia UPM-Serdang 43400 Malaysia

In the present study, the aptitudes of acrylamide grafted cellulose to remove Cu（Ⅱ） ions from aqueous solutions were investigated. The preparation process was carried out through graft copolymerization of acrylamide onto cellulose, using ceric ammonium nitrate as an initiator. Fourier transform Infrared spectroscopy was used to confirm and characterization poly acrylamide-grafted cellulose formation. batch experiments of Cu（Ⅱ） ions adsorption on the grafted cellulose adsorbent were performed. Effects of initial pH of the solution, contact time and initial Cu（Ⅱ） concentration on the adsorption of Cu（Ⅱ） were studied. The maximum adsorption of Cu（Ⅱ） ion on grafted cellulose is observed 90 mg/g at the initial pH of 6. Equilibrium time was reached within 3h. Kinetic data were analyzed using the pseudo-first-order, pseudo-second-order equations. The data fitted very well to the pseudo-second-order rate expression. The equilibrium data for adsorption isotherms of these metal ions on grafted cellulose were obtained using the Langmuir and Freundlich models and the Langmuir model was obtained to be in better correlation with the experimental data. The results showed that acrylamide-g-cellulose developed in this study could be an economical and effective adsorbent for application in removal of copper ion from water and waste waters.

关键词： Adsorption Cu(Ⅱ) cellulose kinetics isotherm.

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怎样做体操教练员一版

Spontaneous combustion of coals and coal-shales

丛书名：书名原文:Записки тренера гимнаста

1959年

作者：（苏）m.b.李文周其勉张桂芬译

来源：汇雅图书（南通市图书馆... 评论

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International Journal of mining Science and Technology 2018年第6期28卷 933-940页

作者： m.Onifade b.Genc The School of mining Engineering University of the Witwatersrand

Spontaneous combustion of coal is a well-known phenomena around the globe. Apart from the coal itself,burning coal-shales is becoming a problem in the South African coal mines. Serious incidents of spontaneous combustion have been reported as a result of self-heating of reactive coal-shales. The intrinsic properties and spontaneous combustion tests of 28 selected coal and coal-shale samples were conducted and a relationship between the two has been established. Intrinsic properties were obtained by using the proximate and ultimate analysis, and spontaneous combustion liability tests results were obtained by using the Wits-Ehac and Wits-CT indices. The experimental results show that intrinsic properties of these materials complement to the spontaneous combustion liability tests results. Comparative analyses of intrinsic properties and spontaneous combustion characteristics indicate similarities between the mechanism of coal oxidation and that of the oxidative processes undergone by coal-shales. For the tested samples, coal samples have a higher intrinsic spontaneous combustion reactivity rating than the ***, an increase in carbon, moisture, hydrogen, volatile matter, nitrogen and a decrease in ash content indicate an increased proneness to self-heating. The concentration of pyrite found in the coal-shales accelerates self-heating. The event of spontaneous combustion can occur if coal-shales absorb sufficient oxygen when subjected to atmospheric conditions.

关键词： Spontaneous combustion Coal-shales Proximate and ultimate analysis Wits-Ehac index Wits-CT index