基于多层转子结构的可控磁通电机有限元分析

针对单层转子结构可控磁通电机磁通控制电流过大的问题,提出一种三层转子结构的可控磁通永磁电机.对电机空载特性、工作状态特性、电机状态改变的磁通控制特性进行了有限元仿真.仿真表明该电机能够满足车用电机的需求,并且能减小磁通控制电流.     

六相双Y移感应电机的MagNet有限元分析

本文构建六相双Y移感应电机模型,提出了基于有限元分析软件Mag Net的六相双Y移感应电动机建模和仿真方法。利用Mag Net建立六相双Y移感应电机2D仿真模型,对电磁场分布进行二维时谐分析,可以判断电机是否有磁场漏磁,并对电机的起动性能进行二维瞬态运动场仿真求解,根据电机的电磁转矩、转速、转子电流、定子电流的仿真波形进行分析,结果表明六相双Y移感应电机起动响应速度快、运行平稳。     

大负载精密驱动超磁致伸缩直线电机动力学建模与仿真

基于一种新型的精密大负载超磁致伸缩直线电机进行了整机动力学建模和仿真,尝试分析巨磁致伸缩直线电机的频率特性和负载特性,提供了一种对于尺蠖运动超磁致伸缩直线电机进行整机建模和性能分析的有效方法. 在建模过程中,采用Jiles Atherton磁滞模型以补偿磁滞回对直线电机输出的影响,并提出了直线电机驱动大负载时的滚动摩擦修正. 通过建模与仿真,验证了直线电机结构设计方案的可行性. 仿真和实验对比结果表明,该动力学模型实现了超磁致伸缩直线电机的变激励、变负载运动的准确模拟.     

电枢绕组断路故障对永磁风力发电机电磁场的影响

以一台1.5 MW、并联支路数为4的分数槽永磁风力发电机为例,建立了永磁风力发电机的二维场路耦合有限元电磁场计算模型,对比分析了永磁风力发电机带额定负载运行过程中,发生电枢绕组支路断路和单相断路两种断路故障对电机电磁场的影响.研究了两种断路故障下电机气隙磁密各次谐波、支路电流及转子表面所受电磁力密度的变化规律,为永磁同步风力发电机电枢绕组断路故障诊断提供了理论依据.     

新型三相磁控电抗器的研究

电力系统中的三相磁控电抗器都采用每个铁芯柱加磁阀的三相六柱式磁控电抗器,这种电抗器的铁芯柱磁阀加工过程复杂,并且运行中噪音较大,为了克服这种缺陷,提出了一种新型三相磁控电抗器.使用电磁场分析软件Ansoft对该新型磁控电抗器模型进行了仿真,得到了其工作状况的一些仿真数据和结果.仿真分析结果验证了通过调节晶闸管的触发角可以平滑地调节电抗器的电抗的特性,同时也对该三相磁控电抗器的电磁场分布情况进行了仿真分析.     

基于Maxwell 3D的永磁刹车系统中永磁装置的磁路仿真和研究

介绍了磁刹车原理,利用三维电磁场有限元分析软件Maxwell 3D实现磁刹车系统中磁场分布的仿真计算。仿真两种不同的材料对磁通量密度分布的影响。为磁刹车系统中永磁设备的设计和研制提供了一定的依据。     

基于状态观测器的异步电子磁链观测和速度辨识

提出一种基于全阶观测器的感应电机磁链估计方法,系统地给出了这种观测器的设计过程.仿真研究表明,该方案对电机参数变化的鲁棒性较好,磁链观测精度高.根据李雅普诺夫稳定性原理推导出基于自适应状态观测器的直接转矩控制系统速度辨识算法,其收敛速度快、精度高.基于状态观测器方案在准确观测电机磁链的同时,可实现高性能的无速度传感器运行.     

基于EKF感应电机直接转矩控制状态观测器的新设计

从扩展卡尔曼滤波算法原理入手,利用定子侧可测量的电流、电压,推导出一种新的无转速传感器的电机转速、磁链状态观测模型,估算出电机的转速和定子磁链.仿真结果表明这种方法能有效地解决磁链和转矩的脉动问题,从而实现电机高性能的控制.     

车用内置径向式永磁同步电机的降振优化设计

为降低永磁同步电机径向电磁力所引起的电磁振动噪声,基于电磁场、结构场以及声场有限元分析方法,提出了一种基于隔磁磁桥偏移的优化方法.以一台车用内置径向式永磁同步电机为研究对象,将电机隔磁磁桥所在位置沿转子外径的圆周轨迹向磁极方向偏移,同时对隔磁磁桥相邻间距与隔磁磁桥长度进行优化,在综合考虑电机振动噪声水平与电机性能的前提...     

组合式永磁同步直线电机端部效应力研究

为了改善永磁同步直线电机的推力波动特性,针对其结构特点,提出了组合式永磁同步直线电机这一新型结构并介绍了组合式永磁同步直线电机的结构特点;以平板式短初级长次级永磁同步直线电机为例,用傅立叶级数方法对传统永磁同步直线电机和组合式永磁同步直线电机的端部效应力进行了分析,获取了最小化端部效应力的铁芯长度选取方法;利用有限元方法对两种电机的端部效应力解析结果进行仿真验证,用两种电机的原型样机实验平台进行了静磁阻力实验.仿真和实验结果表明,组合式永磁同步直线电机有效减小了端部效应力和静磁阻力,使电机的推力波动特性得到明显的改善.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.