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四轮底盘转向方式对工作行程率影响的研究 被引量:5
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作者 吕莹 吴潇 +1 位作者 符耀明 李志伟 《农机化研究》 北大核心 2015年第5期71-74,81,共5页
实现四轮底盘小半径转弯,提高小地块工作行程率可提高农业机械的作业效率。通过对现有的四轮拖拉机在小地块作业时转弯半径、地头宽度对空行时间的影响分析,得出提高小地块空行时间的关键是底盘要具有转弯半径小、不需要倒车便可直接驶... 实现四轮底盘小半径转弯,提高小地块工作行程率可提高农业机械的作业效率。通过对现有的四轮拖拉机在小地块作业时转弯半径、地头宽度对空行时间的影响分析,得出提高小地块空行时间的关键是底盘要具有转弯半径小、不需要倒车便可直接驶入下一畦的转向形式。作者认为前桥摆转转向方式四驱底盘更加适合小地块作业。该底盘在转向时,通过控制前桥驱动轮的转动,使前桥主动围绕着前桥中心点的转向装置转动,带动底盘以任意角度转向。通过将前桥摆转转向式底盘的工作行程率与偏转式底盘相比较,证明前桥摆转转向底盘更能提高小地块工作行程率。 展开更多
关键词 农业机械 四轮底盘 前桥摆转式 小转弯半径 工作行程率
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犁耕机组作业行程率计算及试验验证 被引量:2
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作者 田志宏 张桐华 +1 位作者 朱瑞祥 姚万生 《西北农业大学学报》 CSCD 1996年第2期51-55,共5页
在分析现有机组作业行程率计算公式的基础上,就犁耕作业推导出新的计算公式和最佳小区宽度计算式。与现有公式相比,新算式具有较强的理论性和实用性,尤适于小地块作业情况。试验结果证实了新算式的正确性。
关键词 犁耕作业 作业小区 行程率 机组时间利用
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基于Matlab的开闭垄行走法工作行程率的研究
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作者 张俊 《科技视界》 2015年第29期173-173,共1页
机组在作业行走时,一个重要的行走方式是直行法中的开闭垄行走法。本文用Matlab软件绘制了当机组幅宽Bz为2,5,7m时,工作行程率与作业小区长度L、宽度C和长宽比k之间的关系图,拟对机组在采用开闭垄行走法在田间行走时对作业长宽的取值来... 机组在作业行走时,一个重要的行走方式是直行法中的开闭垄行走法。本文用Matlab软件绘制了当机组幅宽Bz为2,5,7m时,工作行程率与作业小区长度L、宽度C和长宽比k之间的关系图,拟对机组在采用开闭垄行走法在田间行走时对作业长宽的取值来提高其工作行程率。 展开更多
关键词 开闭垄行走法 工作行程率 MATLAB
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1985~1995年乌鲁木齐铁路局车辆伤害事故剖析及对策 被引量:1
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作者 李志民 宋连生 《中国铁路》 1997年第8期36-39,共4页
1985~1995年乌鲁木齐铁路局车辆伤害事故逐年增加,行程伤亡率呈上升趋势,但职工车辆伤害事故呈下降趋势,而路外伤亡事故却呈上升趋势。文中剖析了产生此种现象的原因,阐述其特点和规律,并提出了相应的对策。
关键词 车辆 伤害事故 乌鲁木齐 行程伤亡 铁路运输
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Adsorption of Rhenium(Ⅶ) with Anion Exchange Resin D318 被引量:11
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作者 舒增年 杨明华 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第3期372-376,共5页
The adsorption and mechanism of Re(Ⅶ)on resin D318 were studied using chemical methods and IR spectrometry.At pH 5.2,the static and dynamic saturation adsorption capacities were 351.4 and 366.5 mg·g-1,respective... The adsorption and mechanism of Re(Ⅶ)on resin D318 were studied using chemical methods and IR spectrometry.At pH 5.2,the static and dynamic saturation adsorption capacities were 351.4 and 366.5 mg·g-1,respectively.The adsorption behavior obeyed the Freundlich empirical equation and the adsorption rate constant k298 was 6.37×10-4s-1.The desorption percentage was up to 99.7%when 2.0 mol·L-1KSCN was used for dynamic desorption. 展开更多
关键词 RHENIUM resin D318 ADSORPTION DESORPTION
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Unsaturated expansive soil fissure characteristics combined with engineering behaviors 被引量:13
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作者 李雄威 王勇 +1 位作者 俞竞伟 王艳丽 《Journal of Central South University》 SCIE EI CAS 2012年第12期3564-3571,共8页
The relationship among the surface fissure ratio, moisture content, seepage coefficient and deformation modulus of field unsaturated expansive soil in Nanning, Guangxi Province, China, was obtained by a direct or indi... The relationship among the surface fissure ratio, moisture content, seepage coefficient and deformation modulus of field unsaturated expansive soil in Nanning, Guangxi Province, China, was obtained by a direct or indirect method. Digital images of expansive soil of the surface fissure with different moisture contents were analyzed with the binarization statistic method. In addition, the fissure fractal dimension was computed with a self-compiled program. Combined with in situ seepage and loading plate tests, the relationship among the surface fissure ratio, moisture content, seepage coefficient and deformation modulus was initially established. The surface fissure ratio and moisture content show a linear relation, "y=-0.019 1x+1.028 5" for rufous expansive soil and "y=-0.07 1x+2.610 5" for grey expansive soil. Soil initial seepage coefficient and surface fissure ratio show a power function relation, "y=1× 10^-9exp(15.472x)" for rufous expansive soil and "y=5× 10^-7exp(4.209 6x)" for grey expansive soil. Grey expansive soil deformation modulus and surface fissure ratio show a power fimction relation of "y=3.935 7exp(0.993 6x)". Based on the binarization and fractal dimension methods, the results show that the surface fissure statistics can depict the fissure distribution in the view of two dimensions. And the evolvement behaviors of permeability and the deformation modulus can indirectly describe the developing state of the fissure. The analysis reflects that the engineering behaviors of unsaturated expansive soil are objectively influenced by fissure. 展开更多
关键词 expansive soil surface fissure ratio fractal dimension PERMEABILITY deformation modulus
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Kinetic Behavior of Aggregation-Exchange Growth Process with Catalyzed-Birth
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作者 HAN An-Jia CHEN Yu LIN Zhen-Quan KE Jian-Hong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3期479-486,共8页
We propose an aggregation model of a two-species system to mimic the growth of cities' population and assets, in which irreversible coagulation reactions and exchange reactions occur between any two aggregates of th... We propose an aggregation model of a two-species system to mimic the growth of cities' population and assets, in which irreversible coagulation reactions and exchange reactions occur between any two aggregates of the same species, and the monomer-birth reactions of one species occur by the catalysis Of the other species. In the case with population-catalyzed birth of assets, the rate kernel of an asset aggregate Bκ of size k grows to become an aggregate Bκ+1 through a monomer-birth catalyzed by a population aggregate Aj of size j is J(κ,j) = Jkjλ. And in mutually catalyzed birth model, the birth rate kernels of population and assets are H(k,j)=Hkjη and J(k,j) = Jkjλ, respectively. The kinetics of the system is investigated based on the mean-field theory. In the model of population-catalyzed birth of aseets, the long-time asymptotic behavior of the assets aggregate size distribution obeys the conventional or modified scaling form. In mutually catalyzed birth system, the asymptotic behaviors of population and assets obey the conventional scaling form in the case of η=λ =0, and they obey the modified scaling form in the case of η=0, λ=1. In the case of η = λ= 1, the total mass of population aggregates and that of asset aggregates both grow much faster than those in population-catalyzed birth of assets model, and they approaches to infinite values in finite time. 展开更多
关键词 kinetic behvavior aggregation-exchange growth catalyzed-birth scaling law rate equations
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HBFTrans2: A Maple Package to Construct Hirota Bilinear Form for Nonlinear Equations
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作者 杨旭尔 阮航宇 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第5期747-752,共6页
An improved algorithm for symbolic computation of Hirota bilinear form of nonlinear equations by a logarithm transformation is presented. The improved algorithm is more efficient by using the property of Hirota-D oper... An improved algorithm for symbolic computation of Hirota bilinear form of nonlinear equations by a logarithm transformation is presented. The improved algorithm is more efficient by using the property of Hirota-D operator. The software package HBFTrans2 is written in Maple and its running efficiency is tested by a variety of soliton equations. 展开更多
关键词 Hirota bilinear form nonlinear equation symbolic computation
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Study on Emulsifier Wastewater Treatment through UASB+SBR Technology
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作者 LU Cheng-dong JIANG Dong +2 位作者 LAN Feng-gang LIU Feng MA San-jian 《Chinese Food Science》 2012年第3期46-49,共4页
[Objective] The aim was to study the COD removal effect of emulsifier wastewater and provide experimental basis for the design, adjustment and operation of project. [Method] Using UASB+SBR technology to process emulsi... [Objective] The aim was to study the COD removal effect of emulsifier wastewater and provide experimental basis for the design, adjustment and operation of project. [Method] Using UASB+SBR technology to process emulsifier wastewater, the problems in operation process were discussed. [Result] The experiment carried out for 71 d, under the situation of large changes of COD concentration (the highest: 10 924 mg/L, the lowest: 2 880 mg/L, mean value: 5 751 mg/L), COD removal efficiency of UASB was around 70% and the COD removal efficiency of SBR was above 70%, which met the emission standard. [Conclusion] The combined technology had good treatment effect on the emulsifier wastewater. 展开更多
关键词 UASB SBR method Emulsifier wastewater TRIAL COD concentration China
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网络行程时间可靠性评价方法与影响因素 被引量:12
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作者 陈喜群 刘教坤 +2 位作者 胡浩强 崔尔佳 张帅超 《交通运输工程学报》 EI CSCD 北大核心 2018年第4期132-142,共11页
采用区域划分方法研究了网络行程时间率的概率分布,提出了基于OD对的网络行程时间可靠性指标以评价城市交通可靠性;选取影响行程时间可靠性指标的相关因素,建立了多元线性回归模型,用逐步回归法求解模型,并进行了模型参数显著性检验;根... 采用区域划分方法研究了网络行程时间率的概率分布,提出了基于OD对的网络行程时间可靠性指标以评价城市交通可靠性;选取影响行程时间可靠性指标的相关因素,建立了多元线性回归模型,用逐步回归法求解模型,并进行了模型参数显著性检验;根据杭州市和北京市的网约车数据计算了网络行程时间可靠性指标,并与高峰拥堵延迟指数进行对比,分析了网络行程时间可靠性指标的时间和空间分布规律。研究结果表明:在多元线性回归模型中,规划行程时间率与等待时间、费用、距离、行程时间和OD对间行程次数这5个自变量拟合得到的决定系数为0.772,平均行程时间率与5个自变量拟合得到的决定系数为0.857,2个模型拟合程度均较好,回归模型显著;规划行程时间率回归模型中等待时间、行程时间和实际行程距离的回归系数分别为0.386、0.399与-1.286,平均行程时间率回归模型中等待时间、行程时间和实际行程距离的回归系数分别为0.162、0.177与-0.676,2个交通可靠性指标都与等待时间和行程时间呈正相关,和实际行程距离呈负相关;提出的网络行程时间可靠性指标与高峰拥堵延迟指数变化趋势一致,较好地符合现实交通状况,从多角度反映了交通可靠性特征,可以为路网规划提供决策支持,帮助居民更好地进行出行路径选择。 展开更多
关键词 交通规划 行程时间 多元线性回归 可靠性指标 显著性检验 高峰拥堵延迟指数
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Nonlinear behavior of electrodynamic loudspeaker suspension at low frequencies 被引量:2
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作者 FENG ZiXin SHEN Yong +1 位作者 HENG Wei LIU YunFeng 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第7期1361-1365,共5页
The suspension of electrodynamic loudspeakers includes a surround of the cone and a spider, and it is characterized by the mechanic stiffness in the lumped-parameter model. By solving the nonlinear differential equati... The suspension of electrodynamic loudspeakers includes a surround of the cone and a spider, and it is characterized by the mechanic stiffness in the lumped-parameter model. By solving the nonlinear differential equation of motion which considers the nonlinearity of suspension at low frequencies numerically and measuring different kinds of surrounds and spiders, the nonlinear behavior of suspension is theoretically and experimentally studied. Since the nonlinear stiffness of spiders and surrounds can be measured and fitted respectively before assembled into loudspeakers, which spider works best with which surround is studied. The performance of loudspeakers such as harmonic distortion based on the nonlinear parameters can be predicted. 展开更多
关键词 nonlinear stiffness SURROUND SPIDER
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