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The inf.uence of.jaw's curvature on the results of.the Brazilian disc test

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Journal of.Rock Mechanics and Geotechnical Engineering 2016年第2期8卷 127-146页

作者： Ch.f.Markides S.K.Kourkoulis Department of.Mechanics School of Applied Mathematical and Physical SciencesNational Technical University of Athens

The general contact problem of.a disc squeezed between jaws of.arbitrary curvature is considered employing Muskhelishvili’s complex *** advantage of.the general solution introduced,the closed-f.rm expressions f.r the stresses along strategic loci(loaded rim,loaded diameter,disc’s center)are obtained,in terms of.the ratio r of.the disc’s to the jaw’s ***,the ef.ect of.r(as well as that of.the relative stif.ness of.the disc’s and jaw’s materials dictating the contact arc)on the stress distribution along these loci is *** is concluded that,f.r both smooth contact(zero f.iction)and contact with f.iction,the role of.the jaw’s curvature is signif.cant not only along the disc-jaw contact arc(as it could be expected),but also all along the loaded *** the other hand,it is indicated that the stress f.eld at the disc’s center is more or less insensitive to the jaw’s curvature assuming that r lies within the range(0,0.67)or in other words within the limits def.ned by the two standardized suggestions,*** of.American Society f.r Testing and Materials(ASTM)(plane loading platens with r ? 0)and that of.International Society f.r Rock Mechanics(ISRM)(curved jaws with r ? 0.67).The upper limit of.this range is a kind of.compromise between the need to make the stress f.eld at the disc’s center independent of.the boundary conditions while keeping at the same time the contact angle large enough to reduce the stress concentration and the risk f.r premature f.acture initiation f.r f.om the disc’s *** jaws with radius of.curvature exceeded by that suggested by ISRM,the stress f.eld at the disc’s center is signif.cantly *** f.r jaws with radius approaching that of.the disc,the stress f.eld at the disc’s center is dramatically distorted rendering Hondros’ f.rmula inapplicable and the test results erroneous.

关键词： Brazilian disc test Elastic contact Complex potentials Stress f.eld f.ictional stresses

APPROXIMATE ANALYTICAL SOLUTIONS f.R SOME STRONGLY NONLINEAR PROBLEMS

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Science China Mathematics 1990年第7期33卷 843-853页

作者：戴世强 G.f.SIGALOV A.V.DIOGENOV Shanghai Institute of.Applied Mathematics and Mechanics Shanghai University of Technology Shanghai 200072 PRC f.culty of.Mathematics Irkutsk State University USSR

In this paper, some problems of.strongly nonlinear oscillations and waves are analyzed by using the modif.ed method of.f.ll approximation developed by the authors. f.rstly, a class of.strongly nonlinear oscillation systems is studied and, in particular, f.r the modif.ed van der Pol oscillator, the second-order expression of.its limit cycle solution is quite straightf.rwardly f.und out, which agrees with the results obtained by way of.the generalized method of.averaging in Ref. [1]. Then f.r the modif.ed KdV equation, the correct secondorder appoximate solution of.solitary waves is given. f.nally, f.r the generalized KdV equation with a f.f.h-order dispersion term, the third-order asymptotic solution of.solitary waves is derived and the f.rm of.oscillatory solitary waves is analytically given. All the results show that the modif.ed method of.f.ll approximation can be ef.ectively applied to the investigation of.some mathematical problems with strong nonlinearity.

关键词： strong nonlinearity asymptotic solution modif.ed method of f.ll approximation.

Mineralogy of.Selected Paddy Soils in Southeastern China

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Pedosphere 1997年第4期7卷 289-296页

作者： f.L.WANG P.M.HUANG Departmentof.oilScience UniversityofSaskatchewanSaskatoonS7N5A8（Canada） Departmentof.oilScience Uni

Limited inf.rmation is available concerning the mineralogy of.paddy soils in the southeastern *** chemical methods in conjunction with X-ray dif.ractometry, we studied the mineral composition of.three paddy soils: Jinghua (paddy soil on Quaternary red clay), f.yang (Hapl-percogenic loamy paddy soil), and Shaoxing (gleyic clayey paddy soil). All the soils contained quartz, mica, vermiculite, chlorite and kaolinite, and the distribution of.these minerals varied with soil particle size f.actions. The clay f.action of.the f.uyang and Shaoxing soils also contained smectite. Although X-ray data did not show the presence of.smectite in the Jinghua soil, this mineral was identif.ed by the chemical method, suggesting a transitional property of.the mineral in the soil. Hydroxy-Al interlayered minerals were also present in the clay *** amount of.smectite in the soils was 31.6 (Shaoxing), 16.5 (f.yang), and 21.4 (Jinghua) g kg-1; f.r vermiculite it was 33.3 (Shaoxing), 16.5 (f.yang), and 8.5 (Jinghua) g kg-1. Smectite was only f.und in the clay f.action. In contrast, amounts of.vermiculite in soil particle size f.actions were 3.0～11.4 (sand),2.1～6.0 (coarse silt), 4.6～18.9 (medium silt), 0.9～40.0 (f.ne silt), and 17.0～108 (clay) g kg-1. The amount of.noncrystalline aluminosilicates in the soils in g kg-1 decreased in the order: Shaoxing (2.4) > Jinghua (1.9) > f.yang (1.7). This study has provided usef.l mineralogical inf.rmation that is f.ndamental in f.ture developmellt of.management strategies of.the soils.

关键词： hydroxy-Al interlayered minerals mineralogy noncrystalline materials paddy soils

Electrical Relaxation in Mixed Alkali Bi_2O_3-K_2O-Li_2O-f._2O_3 Glasses

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Journal of.Materials Science & Technology 2006年第5期22卷 701-707页

作者： E.E.Shaisha Sh.f.El-Desouki I.Shaltout A.A.Bahgat Department of.physics f.culty of.science Al-Azhar UniversityNasr CityCairo 11884Egypt

A new glass system （Bi2O3）50（f.2O3）10（Li2O）x（K2O）40-x, where x changes in steps of.5 mole f.action between 0 and 40, was selected to study the electrical relaxation and the mixed alkali ef.ect （MAE） phenomena. Measurements of.ac conductivity σac, dielectric permittivity ε′ and loss f.ctor tanδ in the f.equency range of.0.12～10^2 kHz and in the temperature range of.300～650 K were carried out. The temperature dependence of.the ac conductivity shows a slow increasing rate at low temperature and high f.equency and a rapid increase at high temperature and low f.equency. At constant temperature, the ac conductivity is f.und to be proportional to ω^8, where s is the f.equency exponent, which is less than 1. Analysis of.the conductivity data and the f.equency exponent shows that the overlapping large polaron tunnelling （OLPT） model of.ions is the most f.vorable mechanism f.r the ac conduction in the present glass system. The ac response, the dc conductivity and dielectric relaxation have the same activation energy and they originate f.om the same basic transport mechanism. The results of.the dielectric permittivity show no maximum peak in the temperature and f.equency range studied. This absence of.maximum peak is an indication of.non-f.rroelectric behavior of.all the studied samples. The MAE has been detected in the ac conductivity, which is the same as the classical MAE in the dc conductivity. The electrical parameters such as dielectric permittivity ε′ and real dielectric modulus M′ show a typical minimum deviation f.om linearity by about two orders of.magnitude. The loss f.ctor tanδ and the imaginary dielectric modulus M″ are insignif.cantly dependent on composition even at the same transition temperature Tg.

关键词： Dielectric permittivity Dielectric modulus Loss f.ctor Conduction mechanism MAE (mixed alkali ef.ect)

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无机化学前沿

促进文明间的对话与国家间的和平:以土耳其为视角(英文)

1988年

作者：（美）巴索洛（Basolo f.）高忆慈等编译

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促进文明间的对话与国家间的和平:以土耳其为视角(英文)

Short-time Oxidation of.Alloy 690 in High-temperature and High-pressure Steam and Water

北京论坛（2004）文明的和谐与共同繁荣

作者： Oktay f. Tanrisever Middle East Technical University Ankara-TURKEY

In this paper, I will attempt to explore the relationship between multiculturalism and peace in the 21st century. It is in this context that the promotion of.multiculturalism in the

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Journal of.Materials Science & Technology 2012年第6期28卷 562-568页

作者： f.Huang J.Q.Wang E.H.Han W.Ke State Key Laboratory f.r Corrosion and Protection Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The oxidation behavior of.alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ f.r 1 h was investigated by scanning electron microscopy （SEM）, atomic f.rce microscopy （Af.） and X-ray photoelectron spectroscopy （XPS）. In high-temperature and high-pressure steam, the oxide f.lm is composed of.an outermost Ni-rich hydroxides layer, an intermediate layer of.hydroxides and oxides enriched in Cr, an inner oxide layer. The f.lm f.rmed in high-temperature water is similar to that in steam, except f.r missing the Ni-rich hydroxides layer. Samples with dif.erent surf.ce f.nishes （electropolished, mechanically polished, ground, and as-received） were prepared f.r comparison. A general increase of.the oxide thickness with the degree of.surf.ce roughness is observed. The equivalent oxide thicknesses lie in the range of.100-200 nm f.r the as-received samples, 150-250 nm f.r the samples ground to 400# and 10-20 nm f.r the samples ground to 1500#, mechanically polished, and electropolished.

关键词： Alloy 690 Oxidation High-temperature water Surf.ce f.nish X-ray photoelectron spectroscopy (XPS)

Semi-solid processing of.hypereutectic A390 alloys using novel rheof.rming process

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Transactions of.Nonf.rrous Metals Society of.China 2010年第9期20卷 1743-1748页

作者： M.TEBIB J.B.MORIN f.A JERSCH X.GRANT CHEN Université du Québec à Chicoutimi cole polytechnique de Montréal

The f.asibility of.semi solid processing of.hypereutectic A390 alloys using a novel rheof.rming process was investigated. A combination of.the swirl enthalpy equilibration device （SEED） process, isothermal holding using insulation and addition of.solid alloy during swirling was introduced as a novel method to improve the processability of.semi solid slurry. The ef.ects of.isothermal holding and the addition of.solid alloy on the temperature gradient between the centre and the wall and on the f.rmation of.a（Al） particles were examined. In additional tests, phosphorus and strontium were added to the molten metal to ref.ne the primary and eutectic silicon structure to f.cilitate semi solid processing. The results show that the combination of.the SEED process with two additional processing steps can produce semi-solid A390 alloys that can be rheoprocessed. The microstructure reveals an adequate amount of.non-dendritic a（Al） globules surrounded by liquid, which greatly improves the processability of.semi-solid slurry.

关键词： semi-solid f.rming rheof.rming process hypereutectic A390 alloys microstructure

风洞模拟建筑物对大气污染物扩散影响的若干问题讨论

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实验流体力学 2006年第3期20卷 63-70页

作者：汪新 McNamara K f 广东工业大学建设学院广州510090 爱尔兰国立大学土木工程系

通过相似性分析,得到了大气污染建筑物影响风洞试验应满足的基本相似条件。由一个实例研究了利用常规风洞模拟装置和测试仪器进行大气污染建筑物影响风洞试验在技术上的可行性。结果显示:由于模拟装置和仪器条件的限制,在大多数风洞试... 详细信息

通过相似性分析,得到了大气污染建筑物影响风洞试验应满足的基本相似条件。由一个实例研究了利用常规风洞模拟装置和测试仪器进行大气污染建筑物影响风洞试验在技术上的可行性。结果显示:由于模拟装置和仪器条件的限制,在大多数风洞试验中存在大气边界层不完全模拟和仪器响应过慢等问题,但通过合理模拟来流的主要湍流特征和改进采样方法,可以在风洞中较真实地模拟建筑物对大气扩散的影响。

关键词：空气污染扩散风洞试验建筑物影响