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基于面元法的船舶螺旋桨附连水质量与阻尼计算方法研究

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船舶力学 2019年第1期23卷 9-19页

作者：邹冬林张建波塔娜饶柱石上海交通大学振动冲击噪声研究所上海200240 上海交通大学机械系统与振动国家重点实验室上海200240 高新船舶与深海开发装备协同创新中心上海200240

在船舶轴系振动或桨轴流固耦合分析中,螺旋桨在流场中所引起的附连水质量与阻尼是很重要的参数。但实际计算中螺旋桨附连水质量常常用螺旋桨自身质量乘以一个经验系数得到,而附加阻尼往往被忽略。针对这些不足,文章利用螺旋桨水动力分... 详细信息

在船舶轴系振动或桨轴流固耦合分析中,螺旋桨在流场中所引起的附连水质量与阻尼是很重要的参数。但实际计算中螺旋桨附连水质量常常用螺旋桨自身质量乘以一个经验系数得到,而附加阻尼往往被忽略。针对这些不足,文章利用螺旋桨水动力分析中常使用的面元法,构建了螺旋桨随轴系在水中振动时的附加质量与阻尼数值计算方法。目前求解附加质量的经典方法是基于运动物体引起流体动能变化来求解,但该方法不能求解附加阻尼。文中证明了所提出的方法与经典方法是完全等价的,同时利用该方法还可以求解附加阻尼。最后以球体、椭球体及螺旋桨为对象给出几个算例,并与解析解或其它文献计算结果比较,误差均在合理范围内,表明文中提出的方法的有效性。

关键词：附加质量附加阻尼螺旋桨流固耦合面元法

Effect of CuO particle size on synthesis temperature and microstructure of Al_2O_(3p)-Al composites from Al-CuO system

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Transactions of Nonferrous metals Society of China 2014年第12期24卷 3901-3906页

作者：赵鸽史志铭塔娜张瑞英内蒙古工业大学材料科学与工程学院呼和浩特010051

Al2O3p-Al composites were synthesized using an in-situ reaction in the 80%Al-20%CuO （mass fraction） system. The effects of the CuO particle size on the synthesis temperature and microstructure of the composites were investigated by various methods. The results indicate that the CuO particle size has a significant effect on the temperature at which the complete reaction in the Al-CuO system occurs：the temperature is 200 ℃ lower in the Al-CuO system containing CuO particles with sizes less than 6μm than that containing CuO particles with sizes less than 100μm. The interfacial bonding between Al2O3 particles and Al is not complete when the temperature is below a critical value. The morphology of the Al2O3 particles varies from ribbon-like shape to near spherical shape when the temperature is above a critical value. These two critical temperatures are affected by the particle size of CuO, and the critical temperature of the sample containing CuO particles with sizes less than 6μm is 100 ℃ lower than that of the sample containing CuO particles with sizes less than 100μm.

关键词： CuO particle size synthesis temperature Al2O3p-Al composite

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生活方式视角下的时空行为研究进展

地理科学进展 2016年第10期35卷 1279-1287页

作者：塔娜申悦柴彦威华东师范大学地理科学学院上海200241 华东师范大学现代城市研究中心上海200062 北京大学城市与环境学院北京100871

中国城市转型带来了社会群体的异质化和生活方式的多元化,满足不同群体的社会需求成为人本规划的重要目标,需要城市研究更多地关注微观个体的行为差异。随着城市社会现代化进程的加速和个体生活选择的增加,生活方式、城市空间与时空行... 详细信息

中国城市转型带来了社会群体的异质化和生活方式的多元化,满足不同群体的社会需求成为人本规划的重要目标,需要城市研究更多地关注微观个体的行为差异。随着城市社会现代化进程的加速和个体生活选择的增加,生活方式、城市空间与时空行为三者的互动愈加增强,生活方式对个体时空行为决策具有限制作用,导致个体行为差异的扩大并影响个体对空间政策的应对方式,因而需要在行为研究中增加生活方式的视角。本文从生活方式的相关理论、时间地理学和活动分析法的理论基础出发,综述了生活方式视角下的时空行为研究在国内外的进展,系统介绍这一研究的2个重要方向,包括生活方式的定量测量和基于生活方式群体的行为模式解读,旨在为中国城市时空行为研究提供新的视角。

关键词：时空行为生活方式社会公平生活质量影响机制

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铁基非晶合金的形成能力与力学性能

中国有色金属学报 2008年第4期18卷 614-619页

作者：邱克强塔娜索忠源任英磊沈阳工业大学材料科学与工程学院沈阳110023

采用工业用原材料在铜模铸造条件下研究Fe48-xCr15mo14C15B6Y2mx(m为Ni和Nb;x=0,1,2,3)合金的非晶形成能力与力学性能。TEm和XRD分析表明:当m为Nb和x=2时,可获得直径为7 mm的块体非晶合金,而x=0合金形成非晶的直径小于5 mm。DSC分析表明... 详细信息

采用工业用原材料在铜模铸造条件下研究Fe48-xCr15mo14C15B6Y2mx(m为Ni和Nb;x=0,1,2,3)合金的非晶形成能力与力学性能。TEm和XRD分析表明:当m为Nb和x=2时,可获得直径为7 mm的块体非晶合金,而x=0合金形成非晶的直径小于5 mm。DSC分析表明:Fe48-xCr15mo14C15B6Y2Nix(x=0,1,2,3)非晶合金过冷液相区的温度分别为38.1、43.7、46.0和35.8℃;而Fe48-xCr15mo14C15B6Y2Nbx(x=1,2,3)非晶合金过冷液相区的温度分别为44.4、47.1和34.4℃,过冷液相区的大小与合金非晶形成能力具有良好的对应关系。压缩实验表明:Fe48-xCr15mo14C15B6Y2Nix(x=1,2,3)和Fe48-xCr15mo14C15B6Y2Nbx(x=1,2)合金的压缩断裂强度分别为2 997.9、2 881.9、2 850.7、3 645.7和3 018.9 mPa。而x=0合金的压缩断裂强度为2 518.5 mPa。

关键词： Fe基非晶合金 Ni Nb 非晶形成能力压缩断裂强度

Rotational and translational domains of beta precipitate in aged binary mg-Ce alloys

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Journal of magnesium and Alloys 2021年第3期9卷 1039-1056页

作者： B.Z.Sun H.X.Zhang Y.Dong J.X.Ren Y.Tian G.m.Xie J.tan Y.H.Sun na Xiao School of materials Science and Engineering Northeastern UniversityShenyang 110819China State Key Lab Rolling&Automat Northeastern UniversityShenyang 110819China Key Laboratory for Anisotropy and Texture of materials Ministry of EducationNortheastern UniversityShenyang 110819China Analytical and Testing Center Northeastern UniversityShenyang 110819China

The structural evolution fromβ_(1)(mg_(3)Ce)toβ(mg_(12)Ce)precipitates,which takes place at the over-aged stage of binary mg-Ce alloys,are investigated by high-angle annular dark-field scanning transmission electron *** structural transformation mainly occurs in the{111}_(β1)crystallographic planes,where the newly formedβlattices exhibit two categories of domain structures,namely rotational and translational *** rotational domain is composed of threeβdomains(β_(RA),β_(RB)andβ_(RC)),which are related by a 120°rotation with respect to each other around the 111_(β1)axis of theirβ_(1)parent ***{111}_(β1)crystallographic planes can provide four sets of sublattices with the same orientation for an initial nucleation ofβ*** leads to the formation of four translationalβdomains(β_(ta),β_(TB),β_(TC)andβ_(TD)),among which any two differ by a vector of 1/6112_(β1).We deduce theoretically that there exist twenty-fourβdomains during this ***,considering the interfacial misfit,only one-third of domains can grow up and eventually formsβ***,a majority ofβribbons overlap partiallyβ_(1)plate,which is beneficial to relax interfacial strain amongβ,β_(1)andα-mg matrix(α/β/β_(1)).The configuration of multipleβdomains can effectively regulate interfacial misfit ofα/βandβ/β_(1),which are responsible for enhancing the hardness and strength of mg-Ce ***,this study aims to provide some clues to improve the over-aged performance of magnesium alloys by constructingβdomains and optimizing theα/β/β_(1)interface.

关键词： magnesium alloys HAADF-STEm Rotational domain Translational domain Phase transition interfacial misfit

不同含水率下日光温室土壤温度变化规律的峰拟合法拟合

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农业工程学报 2014年第20期30卷 204-210页

作者：塔娜五十六马文娟陈斌朱英开内蒙古农业大学机电工程学院呼和浩特市010018

为了探讨中国西北寒冷干旱地区冬季日光温室内土壤含水率和温度变化规律,该文对内蒙古呼和浩特市日光温室内土壤温度和含水率进行了测试,并利用峰拟合法对不同含水率下的土壤温度进行了拟合。试验表明,在强蒸发条件下,随着土壤温度的升... 详细信息

为了探讨中国西北寒冷干旱地区冬季日光温室内土壤含水率和温度变化规律,该文对内蒙古呼和浩特市日光温室内土壤温度和含水率进行了测试,并利用峰拟合法对不同含水率下的土壤温度进行了拟合。试验表明,在强蒸发条件下,随着土壤温度的升高,土壤非饱和导水率提高,从而将干湿发生面下方的液态水引入干湿发生面。峰拟合函数的最小拟合度为0.95907。通过计算得知,降低含水率能提高白天和夜间的土壤平均温度。验证估计Extreme函数得知,只要确定偏移y0、中心xc、宽度w、幅值A即可得土壤温度对时间的变化函数。该方法可以有效地减少测试点的数量,并把离散的数据点转化为连续函数从而进行微积分分析,提高检测效率。

关键词：温室含水率土壤温度峰拟合法

A HfC nanowire point electron source with oxycarbide surface of lower work function for high-brightness and stable field-emission

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nano Research 2020年第6期13卷 1620-1626页

作者： Shuai tang Jie tang ta-wei Chiu Wataru Hayami Jun Uzuhashi tadakatsu Ohkubo Fumihiko Uesugi masaki takeguchi masanori mitome Lu-Chang Qin national institute for materials Science TsukubaIbaraki305-0047Japan Graduate School of Pure and Applied Science University of TsukubaTsukubaIbaraki305-8857Japan Department of Physics and Astronomy University of North Carolina at Chapel HillChapel HillNC27599-3255USA

Electric field-induced point electron source is highly demanded for microscopy,spectroscopy,lithography,X-ray tubes,microwave devices,and data ***,the instability in emission current and requirement of ultrahigh vacuum have often limited its extensive *** we report a single-crystalline HfC nanowire with oxycarbide emission surface for stable electron emission at 50 na with fluctuations less than 1%in a vacuum of 4×10^−7 *** emitter has a low work function of 2.5 eV measured by the field emission Fowler-Nordheim curve and it is in good agreement with density functional theory(DFT)*** energy spread is in a range of 0.21–0.26 eV with a corresponding reduced brightness 1.95×10^11−3.81×10^11 A·m^−2·sr^−1·V^−*** HfC nanowire with oxycarbide emission surface is a qualified candidate for the next-generation electron source with high brightness,large current,and low energy spread.

关键词： hafnium carbide oxycarbide nanowire electron emission field emission

Soil Salinity Changes in the Jordan Valley Potentially Threaten Sustainable irrigated Agriculture

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Pedosphere 2013年第3期23卷 376-384页

作者： T.G.AmmARi R.taHHAN S.ABUBAKE Y.AL-ZU'Bi A.taHBOUB R.ta'ANY S.ABU-ROmmAN N.AL-mAnaSEER m.H.STiETiYA Department of Water Resources and Environmental management Faculty of Agricultural Technology Al-Balqa' Applied University Department of natural Resources and Environment Faculty of Agriculture Jordan University of Science and Technology Department of Plant Production and Protection Faculty of Agricultural Technology Al-Balqa' Applied University Department of Biotechnology Faculty of Agricultural Technology Al-Balqa' Applied University Department of Land Water and Environment Faculty of Agriculture University of Jordan

The integrated effect of irrigation and agricultural practices on soil salinity in the Jordan Valley （JV）, where over 60% of Jordan＇s agricultural produce is grown, was investigated in this study during 2009-2010. Due to the differences in agricultural operations, cropping patterns, irrigation management, and weather conditions, 206 top- and sub-soil samples were taken every 1 to 3 km from representative farms along a north-south （N-S） transect with 1 to 2 km lateral extents. Soil electrical conductivity of saturated extract （ECse）, Ca, mg, K, na, Ci, and na adsorption ratio （SAR） were determined in saturated paste extracts. Results indicated that about 63% of soils in the JV are indeed saline, out of which almost 46% are moderately to strongly saline. Along the N-S transect of the JV, ECse increased from 4.5 to 14.1 dS m-1 in top-soil samples. Similar increase was observed for the sub-soil samples. The major chemical components of soil salinity; i.e., Ca, mg, and C1, also showed a similar increase along the N-S transect of the valley. moreover, compared to previous field sampling, results showed that changes in soil salinity in the JV were dramatic. in addition, it was found that C1 imposed an existing and potential threat to sensitive crops in 60% of the soils in the JV, where C1 concentrations were greater than 710 mg L-1. Under the prevalent arid mediterranean conditions, improving the management of .irrigation water, crops, and nutrient inputs and increasing water and fertilizer use efficiencies should be indispensable to conserve and sustain the already fragile agricultural soils in the JV.

关键词： agricultural practices chloride electrical conductivity irrigation water quality soil salinization

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轴系纵振诱发的螺旋桨轴承力特性研究

船舶力学 2022年第2期26卷 172-182页

作者：邹冬林冷子珺徐江海塔娜饶柱石上海交通大学振动、冲击、噪声研究所上海200240 上海交通大学机械系统与振动国家重点实验室上海200240 高新船舶与深海开发装备协同创新中心上海200240

船舶螺旋桨工作时,除了不均匀流场会产生轴承力外,推进轴系振动同样会使螺旋桨产生轴承力。目前针对这类轴承力的研究非常少,因此本文利用面元法结合转子动力学理论构建了考虑不均匀流场与轴系振动同时作用下的螺旋桨轴承力预报模型,基... 详细信息

船舶螺旋桨工作时,除了不均匀流场会产生轴承力外,推进轴系振动同样会使螺旋桨产生轴承力。目前针对这类轴承力的研究非常少,因此本文利用面元法结合转子动力学理论构建了考虑不均匀流场与轴系振动同时作用下的螺旋桨轴承力预报模型,基于该模型探讨了轴系纵向振动与其诱发的螺旋桨纵向轴承力间的相互关系。通过对一系列半径、叶数、螺距比和盘面比不同的螺旋桨进行计算,拟合得到了螺旋桨纵向轴承力的估算公式,最后进行了实验验证。研究表明:轴系纵向振动诱发的螺旋桨纵向轴承力与轴系纵振幅值成正比关系,与纵振频率成平方关系。本文的研究有助于人们进一步加深对螺旋桨轴承力特性的认识。

关键词：轴承力附加轴承力面元法转子动力学轴系振动螺旋桨