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Investigation of Sintered Maraging Steels

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Journal of Materials Science & Technology 2001年第1期17卷 47-48页

作者： S. Chtchegolikhina Far Eastern state Technical university, Vladivostok, Russia Far Eastern state Technol. univ. Vladivostok Russian Federation

Processing of five grades of sintered maraging steels containing 13% Cr, 9% Ni, 1% Ti and different quantities of Mo, Co is described. Variations of ageing temperatures and ageing holding times had resulted in choosing optimum regime of ageing f T=550℃, T=2.5 h. It allowed to receive mechanical properties of these steels like to them for compact steels; UTS=1200 MPa, EL=5.3%, RA=7%, and Charpy impact =1445 kJ/m2. X-ray analysis had shown phases Fe7Mo6, Fe2Mo in steels containing Co and decreasing of the period 'of or-phase lattice in these steels after ageing.

关键词： Investigation of Sintered Maraging Steels

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COSMIC RAYS

Chinese Physics C 2016年第10期40卷 421-428页

作者： J.J. Beatty J. Matthews S.P. Wakely Ohio state univ. Louisiana state univ. univ. of Chicago

29.1. Primary spectra The cosmic radiation incident at the top of the terrestrial atmosphere includes all stable charged particles and nuclei with lifetimes of order 108 years or longer. Technically, ＂primary＂ cosmic rays are those particles accelerated at astrophysical sources and ＂secondaries＂ are those particles produced in interaction of the primaries with interstellar gas. Thus electrons, protons and helium, as well as carbon, oxygen, iron, and other nuclei synthesized in stars, are primaries. Nuclei such as lithium, beryllium, and boron （which are not abundant end-products of stellar nucleosynthesis） are secondaries. Antiprotons and positrons are also in large part secondary. Whether a small fraction of these particles may be primary is a question of current interest.

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PALEOGEOGRAPHY OF THE SEYCHELLES BANKAND THE NORTHWEST MADAGASCAR SHELFDURING THE LAST GLACIO EUSTATICREGRESSION (18,000 a B.P)

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Chinese Journal of Oceanology and Limnology 1989年第1期7卷 89-92页

作者： D.D.Badyukov E.L.Demidenko P.A.Kaplin Dept. of Geography State Univ. Moscow USSRDept. of Geography State Univ. Moscow USSRDept. of Geography State Univ. Moscow USSR

The-Seychelles Bank and Madagascar Shelf in the western Indian Ocean were explored geologically during a cruise of the R/V "professor Shtokman" in 1986. Using the data of relief, sediment characteristics and their sequences of strata, paleogeographic maps (18,000 a B.P.) of these areas were produced. These maps show that the Bank and the Shelf are carbonate platforms with complicated topography. The data indicate an important role of sea level oscillation in relief development of this area.

关键词： carbonate strata lacustrine relief professor Indian cruise northwest sedimentation intrusive

Velocity profile of turbulent sediment-laden flows in open-channels

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International Journal of Sediment Research 2015年第4期30卷 285-296页

作者： Deyu Zhong Lei Zhang Baosheng Wu Yongqiang Wang state Key Laboratory of Hydroscience and Engineering Tsinghua Univ.

In this paper,a study was carried out on the velocity profile of sediment-laden flows in open channels using a two-phase mixture model for two-phase *** governing equations for water-sediment mixtures were derived based on the two-fluid equations for solid-liquid two-phase *** drift velocity,a key variable involved in the two-phase mixture equations,was derived from the equation of momentum conservation for the solid *** drift velocity shows that the inertia of flow,particle turbulence,and collisions effect contribute to the dispersion of the sediment particles in turbulent *** the two-phase mixture equation,the vertical velocity profile of open channel flows was *** analysis indicated that the distribution of the velocity over depth of water-sediment mixtures,composed of two different phases,is significantly affected by the turbulence of water-sediment mixtures and the density ***,the velocity distribution is also affected by other factors including collisions between particles and particle turbulence as a basic feature of two-phase flows where interphase interactions inevitably mark their influence on the velocity *** of this approach with observations for a wide range of experimental conditions are presented in this paper,which show that this approach agrees well with the experiments.

关键词： Velocity profile Sediment-laden flows Turbulence Open-channels

Study on the Relationship between Lamellar Spacing and Growth Rate inthe Regular Eutectic Growthby Monte-Carlo Simulation

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Journal of Materials Science & Technology 2002年第4期18卷 322-324页

作者： Weimin WANG, Junming LIU and Zhiguo LIULaboratory of Solid state Microstructures, Nanjing university, Nanjing 210093, China Lab. of Solid state Microstructures Nanjing Univ. Nanjing 210093 China

A modified Monte-Carlo(MC) method to simulate the regular growth of binary eutectic alloys is presented. It is found that the growth rate has a linear dependence on the chemical potential difference between the solid and liquid; the relation between the lamellar spacing A and growth rate R accords well with the prediction of Jackson-Hunt(JH) theory unless the growth rate is very low.

关键词： Eutectic Monte-Carlo simulation Growth

Characteristics of the Flow and Sediment in the Inner Rivers' Broad-shallow Shifting Reach

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四川大学学报（工程科学版） 2005年第S1期37卷 93-97页

作者： Yang, Shengfa Zhou, Huajun Fang, Duo state Key Lab. of Hydraulics Sichuan Univ. Chengdu 610065 China

Rivers are classified into two *** is the outer river which flows into ocean and the other is the inner river which does not flow into the ocean but into desert or *** inner rivers are the erosive rivers that have been seldom studied so *** on the field survey data,the analysis on the characteristics of the flow and sediment in the inner rivers' broad-shallow shifting (IRBS) *** IRBS reach often bears such the properties as:high gradient bed,usually 10‰or greater;small flow dischar...

关键词： the IRBS reach watershed features flow characteristics sedment transport

A Bed-load function based on kinetic theory

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International Journal of Sediment Research 2012年第4期27卷 460-472页

作者： De-yu ZHONG Guang-qian WANG Lei ZHANG state key laboratory of Hydroscience and Engineering Tsinghua Univ.

Bed-load transport plays a fundamental role in morphological processes of natural rivers and human-made *** paper presents bed-load function derived on the basis of kinetic theory. The bed-load function is obtained by integrating the pick-up rate of bed sediment with respect to its longitudinal travel distance,following the basic concept on bed-load put forward by *** pick-up rate is expressed as an upwards flux of bed sediment and determined by invoking the particle velocity distribution function derived by solving the Boltzmann equation of kinetic theory. Comparisons of the present formula with six other bed-load formulas and the experimental data are also made in this *** results show that the present bed-load formula agrees well with the experimental *** addition,the influences due to collision between particles on bed-load is discussed which shows that an appreciable damping of the intensities of bed-load is observed only when the shear acting on particles is large enough to increase the concentration and intensity of random motion of bed load particles so that the collisions between sediment particles can occur.

关键词： Bed load Sediment transport Open channel flow Turbulence Two phase flow

Influence of Al-Ti-B addition on the microstructure and mechanical properties of A356 alloys

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Rare Metals 2009年第2期28卷 181-186页

作者： Zhu Man Yang Gencang Yao Lijuan Cheng Suling Zhou Yaohe NW Polytech univ State Key Lab Solidificat Proc Xian 710072 Peoples R China

The mechanical properties (σb,σ0.2,and δ) and fracture behavior of tensile specimens of the refined A356 alloys were investigated as a function of the addition level of Al-Ti-B master alloy under both as-cast and T6 heat-treated conditions. The results show that as the addition level of Al-5Ti-1B master alloy increases from 0.1 wt.% to 5.0 wt.%,the mechanical properties of refined A356 alloys improve steadily and then decrease slightly under both as-cast and T6 heat-treated conditions. Also,they display exc...

关键词： Al-Ti-B master alloy mechanical properties fracture behavior aging precipitation phase

Eutectic nucleation in Al-7 wt pct Si-Mg casting alloys

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Acta Metallurgica Sinica(English Letters) 2012年第5期25卷 340-346页

作者： Chen, Zhongwei Ma, Cuiying Zhao, Jing Northwestern Polytech univ State Key Lab Solidificat Proc Xian 710072 Peoples R China

The nucleation of eutectic crystals of hypoeutectic A1-7 wt pct Si-Mg casting alloys modified by Ce and Sr was studied by using differential scanning calorimeter （DSC） and scanning electron microscope （SEM）. DSC results were applied to calculate the values of activity energy and nucleation work of eutectic nucleation for the alloys. These values were decreased and the eutectic nucleation frequency was increased with the addition of Ce and Sr to the alloys. Moreover, the morphology of eutectic silicon in the modified alloys was partially or fully modified as fine, fibrous or coral, and DSC plots show that the eutectic undercooling of A1-7 wt pct Si-Mg alloys were increased with additions of modified agents. The mechanism of eutectic modification is combined actions of the accelerated nucleation and the restricted growth.

关键词： Al-Si-Mg alloy Eutectic nucleation Ce and Sr addition DSC