兆瓦级风力发电机变桨距机构设计及分析

以国产化1MW风力发电机组为研究对象,利用叶素理论,对变桨距机构进行了设计和分析并对驱动力进行了优化计算,为风力发电机的部件选择及进一步分析计算提供参数,为国产化风机的设计提供一定的参考数据.     

The minor third communicates sadness in speech, mirroring its use in music.

There is a long history of attempts to explain why music is perceived as expressing emotion. The relationship between pitches serves as an important cue for conveying emotion in music. The musical interval referred to as the minor third is generally thought to convey sadness. We reveal that the minor third also occurs in the pitch contour of speech conveying sadness. Bisyllabic speech samples conveying four emotions were recorded by 9 actresses. Acoustic analyses revealed that the relationship between the 2 salient pitches of the sad speech samples tended to approximate a minor third. Participants rated the speech samples for perceived emotion, and the use of numerous acoustic parameters as cues for emotional identification was modeled using regression analysis. The minor third was the most reliable cue for identifying sadness. Additional participants rated musical intervals for emotion, and their ratings verified the historical association between the musical minor third and sadness. These findings support the theory that human vocal expressions and music share an acoustic code for communicating sadness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

微机控制车床螺纹加工的软件设计

介绍在微机控制的车床中设计螺纹加工程序时应解决的问题，着重介绍怎样解决车削螺距的精确性和主轴转速的选择问题。     

Z72-2000型风力发电机组变桨系统改造

内蒙古大唐国际新能源有限公司卓资1号风电场Z72-2000型风力发电机组自投运以来,变桨系统多次发生因电动机过载、刹车制动延迟等原因引起的被迫停机故障,严重影响机组的正常运行。通过增大变桨驱动力矩、提高刹车制动敏感性、更换合适的驱动器等改造措施,提高了变桨系统及风机的运行稳定性和可靠性。     

定子双绕组电机槽漏感计算与绕组分布关系的研究

对于定子双绕组电机,两套定子绕组共存于同一槽中,存在互漏感磁链耦合,槽漏感的计算与绕组节距、两套绕组夹角及绕组在槽中的分布有一定的关系,其计算不能套用现有的计算公式,需要进一步地研究。本文主要采用解析法研究不同绕组分布形式下的定子双绕组电机槽漏感的计算问题,导出了相同匝数两套绕组槽自漏感、互漏感与节距之间的关系式。     

MW级风力发电机变桨距控制的研究与实践

从MW级风力发电机主控制系统研发出发,对变桨距控制系统通过系统数学建模与仿真,确立了控制模型,并在风场现场进行实践。在实际运行中,验证了控制算法与PID参数的正确性,并根据现场工况对算法进行适当改进,取得了良好的控制效果。     

中温沥青密封承插口在6m焦炉的应用

介绍了上升管承插口采用中温沥青密封处理的新方法,已成功应用于4座6m焦炉,全年效益可达33万元,改善了作业环境,经济环保效益显著。     

Chemistry of the co-pyrolysis of an aromatic petroleum residue with a pyridine-borane complex

Synthesis of boron-doped mesophase by controlled co-pyrolysis of an aromatic petroleum residue and a pyridine-borane complex, PB, as a boron source, was carried out. Pyrolysis was performed at temperatures ranging from 400 to 440 °C, under 1 MPa nitrogen atmosphere. Soaking time was varied between 1.5 and 6 h, and the boron concentration in the pyrolysis mixtures ranged from 0 to 1 wt.%. The effect of the presence of boron upon solid yield, insoluble content, mesophase development and microstructure was studied. PB reacts with molecules of the petroleum residue and creates B-C bonds, B substituting C in the polyaromatic molecules, with sp² hybridisation, and probably also creating B crosslinking between polyaromatic units. The enhanced reactivity caused by B addition is reflected in an increment of viscosity; as a result, the development of mesophase is strongly increased, but the size of the mesophase structures is decreased to a mosaic texture; B also causes an increase of the interlayer spacing and a noticeable enhancement of insoluble material.     

Flow behavior of mesophase pitch

The objective of this work was to provide a comprehensive rheological and structural study of AR mesophase pitch. The shear viscosity of AR mesophase pitch was found to be qualitatively similar to results from prior investigations of mesophase pitch and followed the typical trend for liquid crystalline fluids. However, a distinct hesitation, or kink, was observed in the shear viscosity curve near the shear thinning to constant viscosity transition. This behavior has been seen previously for some low molecular weight and polymeric liquid crystals and was thought to be due to a transition between tumbling and steady alignment of the uniaxial director. Optical studies of mesophase pitch revealed an orientation change of the poly-domain structure at shear rates where the kink was observed. This orientation change results in a high viscosity to low viscosity transition. This viscosity transition, and not tumbling, is responsible for the kink phenomenon. The optical studies also reaffirmed that shear flow reduces the size of the poly domain structure and elongates the domains along the flow direction. Also under quiescent conditions, the poly-domain size increased with increasing relaxation time.     

新型小波分析方法在风力发电机特殊状态下的应用研究

为了提高风力发电机的电能质量,减小风力发电机在发电过程中的桨叶载荷,提高变桨距执行机构的性能,采用小波分析对风力发电机进行了分析、阈值化与重构,同时对桨叶根部载荷和统一变桨控制器执行机构性能进行分析与评估。以FAST模型为基础在标准风速下对统一变桨风力发电机进行的仿真分析结果表明:小波分析方法能够减少风力发电机发出功率的谐波含量,能够对桨叶载荷进行提前预估,且独立变桨控制器的跟踪效果较好。