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通过对种子机械设备振动监测和对一些故障的分析,介绍了种子机械风机故障的诊断思路、步骤及振动机理,并根据相位对此类故障进行了诊断与分析,提高了故障诊断的准确率.简单介绍现场动平衡技术. 相似文献
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1故障诊断的一般原则1.1检查液压系统工作环境正确的工作环境和工作条件是液压系统正常工作的前提。液压系统要正常的工作,需要一定的工作环境和工作条件作平台,如果工作环境严重不符合该系统正常工作的标准,想要系统不出现故障几乎是不可能的,所以在故障诊断之初我们就应该首先判断并确定液压系统的工作条件和外围环境是否正常。 相似文献
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本研究通过对152份山西省普通菜豆初级核心种质进行农艺性状鉴定及农艺性状多样性分析,旨在明确山西省普通菜豆种质资源的主要类型,各类型及性状的主要农艺性状特征及多样性特点。通过在田间进行农艺性状鉴定,同时利用表型数据,采用聚类分析、多样性分析和主成分分析法,确定了山西省普通菜豆种质资源的主要类型,各类型和各性状的农艺性状特征和多样性特点以及24个表型性状所属的主成分。结果表明山西普通菜豆初级核心种质可划分为5种类型。从各分组多样性来看,半蔓+蔓生-紫茎紫花型和蔓生-籽粒斑纹型多样性指数I最高,而直立型资源多样性指数I最低,从各性状多样性来看,质量性状多样性总体低于数量性状,但粒色则表现出明显丰富的多样性。通过主成分分析,将普通菜豆23个农艺性状归属为7个主成分,初步明确了各主成分代表的农艺性状;通过上述研究,明确了山西普通菜豆主要类型、多样性特征和各主成分代表的主要农艺性状,可为资源鉴定评价提供综合性状指标。 相似文献
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东方红-75拖拉机液压系统故障分析及排除 总被引：1，自引：0，他引：1
本文作者对东方红-75型拖拉机液压系统在工作中出现的农具不能提升、农具提升缓慢、农具不能下降、农具沉降过快、加油口溢出气泡、主控制阀不能定位、操纵手柄不中立、油温过高、油耗量增加、高压软管爆裂等故障原因进行了分析,并提出了每种故障的解决方法. 相似文献
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电网可靠性评估的网络静态等值模型分析 总被引：2，自引：0，他引：2
为缓解大电网可靠性评估的计算复杂性，采取等值参数联合概率密度分布建模的方式开展了外网静态等值研究。在常规确定性静态Ward等值技术基础上，考虑外部区域发电机和线路随机故障，通过计算各种随机故障状态下的外网等值参数，即外网等值注入功率和外网等值串联支路阻抗，基于概率密度估计技术建立了等值参数的联合概率密度分布。外网静态概率等值模型克服了常规确定性静态Ward等值技术的不足，充分计入外网等值参数的随机性，减少了电网可靠性评估计算时间的同时提高了计算精度。对两区域RBTS系统和RTS79系统研究验证了其有效性和准确性。 相似文献
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基于格网GIS的伊通县县域耕地地力评价 总被引：1，自引：1，他引：0
耕地地力是指在特定区域内的特定土壤类型上,立足于耕地自身素质的地力要素的总和。目前通用的评价方法是采用矢量的方法,在评价单元的基础上建立县域耕地资源数据库,采用模糊聚类、主成分分析等方法进行耕地地力综合评价。由于涉及较多矢量数据的叠加,采用该方法会出现大量碎小图斑和栅格挂接值的平均化。Grid方法将所有参评指标数据展布到一定尺寸的地理格网上,解决了矢量单元评价存在的缺点。以吉林省伊通县为例,采用Grid方法作为基本评价单元,以行政单元作为统计单元,对县域耕地地力状况进行了评价。研究将伊通县耕地地力状况分为5级,与环境因子进行了耦合分析并对各级地力耕地的空间分布进行了分乡统计,结果表明：整个伊通县耕地地力状况总体水平比较高,中高产地主要分布在低河漫滩和平坦的河流低阶地上,占耕地总面积的82.12%,低产地主要分布在高丘陵和低山地区。该结果将为耕地资源的合理规划,保护与利用提供数据支撑。 相似文献
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本文对不同类型小麦品种（系）的11个与产量密切相关的农艺性状,生理指标进行了主成分分析。11个原始指标综合成为三个独立的新指标,分别表示“光合同化因子”、“库与碳氮代谢因子”、“库与氮素营养因子”。主成分值与产量相关分析表明,小麦产量与第一、第二主成分值有极显著正相关关系。通过回归分析,建立了小麦产量与主成分值之间的回归方程。它能较好地反映不同类型品种的产量水平。 相似文献
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《分子植物育种》2015,(9)
5S rDNA(即5S r RNA基因)是由120 bp的编码区和非转录间隔区(nontranscribed spacers,NTS)组成的串联重复序列,及其NTS区碱基序列和长度在不同的种间甚至在种内都有差异,从而形成种内和种间特有的不同重复单元类型,不同单元类型各自代表不同的基因组型,因此5S r DNA多基因家族是研究物种基因组结构的有效工具。本研究以生长在不同地区的四个新疆春小麦地方品种(黑芒麦)作为供试材料,通过TA克隆法获得了128个5S r RNA基因重复单元,每个品种都有长度为326~422 bp之间的短5S r DNA片段和长度为481~491 bp之间的长5S r DNA片段。通过多次序列比对,Blast比对,聚类分析等方法将所有序列分为不同的5S r DNA单元类型。在ZM5291和ZM52300中发现了Short A2、Short D1、Short G1、Long A1、Long D1和Long{S1等6种不同的单元类型,而在ZM5306和ZM5343中只发现了Short A2、Short D1、Short G1和Long{S1等4种不同的单元类型,丢失了Long A1和Long D1。依据5S r DNA各单元类型在山羊草属和小麦属二倍体物种及其异源多倍体物种中的分布情况确定这四个春小麦地方品种的基因组型为AABBDD,确实是普通小麦。本研究首次在普通小麦中发现了六种不同的5S r DNA单元类型,6种单元类型在这4个地方品种中的分布情况表明ZM5291和ZM5300 5S r DNA序列的一致进化程度比ZM5306和ZM5343弱,推测生长在不同地区的黑芒麦多倍体物种形成的时代不一样,并ZM5291和ZM5300比ZM5306和ZM5343可能具有来自各基因组祖先的丰富基因资源。本研究结果为鉴别新疆春小麦种质资源的基因组类型以及亲本选配和育种工作提供新的依据。 相似文献
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氯化钠胁迫下转BADH基因水稻农艺性状的主成分及聚类分析 总被引：2，自引：1，他引：1
对31个转BADH基因水稻品系在0.5g/LNaCL胁迫下的抽穗期、株高、穗长、单株有效穗数、成穗率、单穗实粒数、结实率、千粒重和单株籽粒重等9个农艺性状进行了主成分及聚类分析,选出特征根累积贡献率为86.86%的前5个主成分;在主成分分析的基础上,对31个品系进行了系统聚类分析,在欧氏距离D=2、0的水平上将其划分成4大类群：第一类群属于多穗类型,共有10个品系;第二、四类群综合经济性状较好,共有16个品系;第三类群属大粒类型,共有5个品系。 相似文献
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Aimed at the excitative control for synchronous motor, based on main adjust for power factor and aided adjust for power angle,a kind of new control strategy is presented in this paper. In the steady running,the excitation current will be adjusted in keep. power factor constant,and in dynamic running,it will be calibrated by means of power angle when the disturbance happened.For specified object,the improved algorithm of artificial intelligence controller is also presented in the paper,the simulation result shows that the control algorithm is satisfactory. 相似文献
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Based on dynamic time history analysis, dynamic response behavior of an un supported tunnel through fault zone which was simulated by interface and solid elements was studied under uniform input earthquake wave excitation. The analyses of response behaviors, including displacement difference, acceleration magnification, and plastic zones and so on, were carried out when earthquake wave excitation was input along transverse, longitudinal and vertical of tunnel respectively. The results show that simulation method for fault zone is effective; the earthquake causes obvious displacement difference at fault zone and surrounding rock contacting part. The maximal displacement difference reaches to 51.8mm under transverse uniform input earthquake wave excitation. And the displacement difference under vertical and longitudinal is only 44.3% and 23.1% of the transverse value, respectively; the acceleration magnification in fault zone is significantly greater than that in surrounding rock. Shear failure zone appears at the fault zone and surrounding rock contacting part, and it is especially prominent under input longitudinal earthquake wave excitation. It is proposed that fault zone has significantly influence on the dynamic performance of tunnel. The fault zone and the transitional zones are the control zones of seismic design when tunnel passes through fault zone, thus, the study on the anti seismic measures should be further strengthened. 相似文献
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The purpose of a power system is to deliver the power the customers require in real time, on demand, within acceptable voltage and frequency limit, and in a reliable and economic manner. Using NLPNN (New Linear Programming Neural Network) model, the behavior analysis of power system under fault conditions is carried through. The stability and convergence theorems are set up to obtain the resolution for the problem of the load curtailment strategy. A new way is open up to evaluate the reliability of power systems and the great progress in calculation analysis model is achieved. The new calculation technique and theory foundation of reliability evaluation are supplied. 相似文献
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XIAO Yong~ 《保鲜与加工》2004,(11):30-33
The scheme of rapid protection will be possibly implemented by using the channel of communication, as the communication network of distribution power system being increasingly perfect and particular foundation of optical cable. The feeder protection based on communication can quickly and selectively isolate fault section and restructure the distribution network. This method is the direction of distribution automation. The action principles of feeder protection using blocking and allowing signals of directional over-current are analyzed. The directional over-current protection utilizing blocking signals is suitablefor distribution automation. The scheme can locate the fault section and instantly separate it. When feeder terminal unit (FTU) fails to act or communicate is interrupted, the feeder protection in the substation can backup. 相似文献
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To overcome the limitations of the standard ellipsoidal unit neural networks, some new approaches used in ellipsoidal unit neural networks have been proposed. These new approaches address three main issues: firstly, to understand better and represent the nature of fault classification boundaries; secondly, to determine the network structure without the usual trial and error schemes; lastly, to avoid erroneous generalizations. The application in CSTR shows that the ellipsoidal unit networks can possess arbitrary nonlinear classifying ability, nonlinear interfacial describing ability, and obtain accurate and efficient diagnosis results. 相似文献
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Based on the reactive surplus of Chongqing 220 kV main electric power network under low water and low load, and on state of higher system voltage, a thorough research is done on voltage and reactive power of the system power network by means of calculation,analysis and experiments. A main network calculating equivalence model of power network in Chongqing is constructed. And reactive power optimizing calculation is figured out on the Chongqing power network on condition that the loss minimum of the active power network is object function. Several optimizing compensatory schemes are put forward. Based on the calculation result and the analysis of all schemes, the most reasonable and feasible optimizing scheme could be achieved. Meanwhile, the feasibility that the system voltage could be adjusted when generator operating under excitation was demonstrated. According to the experience of under-excitation operation of the same type units , it decreases the system voltage, improves Chongqing power network running performance, and strengthens the coordination and stabilization of system. 相似文献
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Asynchronized Generator can better solve the excessive reactive and stability problem in power system.In order to improve the dynamic and transient performances of an asynchronized turbogenerator(ASTG),excitation control equation of it in the dynamic synchronous reference frame is presented.Control results are simulated in the synchronous and dynamic synchronous reference frames for ASTG.It is shown that the dynamic and transient performances in the dynamic synchronous reference frame are better than those in the synchronous reference frame.Consequently,the control strategy of dynamic synchronous reference frame can shorten more time on the dynamic process of ASTG. 相似文献
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张全贵 《农产品加工．学刊》2010,(8)
切碎滚筒是青饲机的核心工作部件,切碎刀片排布和设计的合理性直接影响青饲机收获饲料的质量和效率。所以,保证切碎质量,减少功率消耗,以及良好的制造工艺性是设计切碎刀片时考虑的主要方面。 相似文献
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A novel method for power transmission line monitoring and fault diagnosis is proposed based on non linear frequency response analysis. The power line carrier signal has been used for on line monitoring of power transmission line. As the non linear frequency response function describes the system inherent characterization, different frequency response patterns corresponding to different operation states of transmission line can be established. Based on the analysis of transmission line characteristics of fault modes, various fault features can be extracted, thereby achieve online monitoring and fault diagnosis on transmission line. Simulation experiments show the effectiveness of the proposed method. 相似文献