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1.
环锭纺纱过程中的纱线断头主要取决于纱线张力与纱线强力之间的矛盾,而纺纱张力是气圈底端纱线张力经由气圈、导纱钩向上传递而产生的.以往关于气圈底端张力的推算大都是在忽略空气阻力和哥氏惯性力的情况下进行的.针对考虑空气阻力和哥氏惯性力影响的情况,对钢丝圈受力及气圈底端张力进行分析计算,并指出随着纺纱的高速化及对纱线质量要求的提高,在研究纱线张力时,应考虑空气阻力及哥氏惯性力.  相似文献   

2.
从气圈纱线的非稳定运动出发,研究了气圈纱线的准稳定运动、稳定运动、气圈纱线的固有振动、强迫振动,重点研究了气圈纱线的共振问题,对环锭纺纱中气圈的形态和张力、气圈纱线的固有频率、临界参数与工作参数的计算进行了探讨,并在俄罗斯IIM—76—SM环锭细纱机上作了实验验证。  相似文献   

3.
提出了一种基于视觉的贴片元件几何特征参数的检测方法。该方法首先采用最大外接矩形的方法实现元件的粗定位及确定边缘的分割点。接着采用Canny算子和Zernike矩边缘检测算子实现边缘的亚像素精确定位。然后,利用分割点将边缘分割成4部分,分别进行直线拟合,得到边缘的直线方程,利用直线和圆弧相切的关系,求得直线和圆弧的切点,采用最小二乘法对两切点间的边缘点进行圆弧拟合得到圆弧的精确值。同时,采用快速傅立叶变换,利用变换后图像的特征,实现端面图像中条纹方向的判定。实验中测得亚像素边缘点的定位精度为0.03pixel,直线拟合精度为0.03pixel,圆弧拟合精度为0.05pixel,端面条纹判断的准确率为100%。理论分析和实验结果表明:本文提出的最大外接矩形分割法、亚像素定位法、直线圆弧拟合法及条纹方向判断法能很好的满足贴片元件几何特征参数自动视觉检测的稳定可靠、精度高及实时性的要求。  相似文献   

4.
基于边缘导向的直边图像亚像素定位方法   总被引:3,自引:1,他引:3  
通过边缘检测,把图像分为边缘区域和非边缘区域,然后在边缘区域内进行边缘定位.根据局部区域内边缘的直线特性,求得小邻域内直线段的高精度位置;再根据边缘区域内边缘的全局直线特性,用线段的中点来拟合整个直线边缘,得到亚像素精度的图像边缘.在拟合的过程中,根据直线段转角的变化剔除了噪声点,提高了定位精度.并且,根据角度和距离区分出不同直线和它们的交点,给出了图像精确的矢量化结果.  相似文献   

5.
提出了一种运用CCD成像测量技术进行大型机械零件轮廓测量的图像测量方法,该方法利用CCD成像技术获得零件轮廓的图像,并使用Marr边缘检测算子精确确定零件轮廓的边缘位置,利用十一点曲率法得到轮廓的角点和切点的大致位置,并对轮廓分段识别。最后采用直线和任意曲线轮廓拟合的数学模型及误差评定方法,判断所测零件的轮廓度是否满足公差要求。该方法代替了传统的模板手工测量,测量效率高,实验表明,此方法达到了理想的测量结果。  相似文献   

6.
利用形参均匀B样条平滑公式,建立了一种盈亏修正的图像边缘检测新方法。首先对图像的原型值点进行盈亏修正,进一步减少原始图像和平滑图像之间的残余误差;然后利用形参均匀B样条修匀公式对修正后的图像拟合光滑曲面;最后求拟合后的光滑曲面的一阶导数极值点或二阶导数的零交叉点作为边缘特征点。试验表明,该方法稳定可靠,精度较高,能够很好地去除伪边缘;同时该方法简洁,便于实时处理。  相似文献   

7.
在环锭纺气圈的分析中,用柱面坐标系计算能简明、清晰地反映空气阻尼力、复合运动诸因素的综合影响.本文介绍了根据照相测量的气圈形态参数计算纱线张力的新方法.  相似文献   

8.
由于单目手术视频的镜头参数未知,仅凭该单目图像难以准确估算内镜镜头下的手术器械的三维坐标.针对这一问题,提出一种手术器械相对工作空间的估计方法.首先,对用U-Net网络分割后的掩膜图像进行直线检测,对图像坐标系下的直线映射到参数空间上的点进行聚类,从而优化直线检测效果.然后,利用边缘线段的相对几何位置特征对因网络分割效果欠佳导致的边缘线段残缺进行补足,从而提取出与目标边缘高度拟合的完整线段.结合目标器械实际尺寸与图像尺寸间的比例关系,利用平行线在投影平面上的消隐点特性计算出目标器械目标点处的实际三维坐标.最后,进行测距实验和轨迹跟踪实验.实验结果表明:该方法较磁导航传感器准确度高、鲁棒性强,距离测量精度可达2.658 1 mm,轨迹拟合度达91.2%,满足实际情况下手术器械相对工作空间的估算要求.  相似文献   

9.
为了实现贴片元件的自动检测,提出了一种基于视觉的贴片元件几何特征参数检测方法.首先采用最大外接矩形法实现元件的粗定位及确定边缘的分割点,并采用Canny和Zernike矩边缘检测算子实现边缘的精确定位.然后,利用分割点将边缘分割成4部分,分别进行直线和圆弧拟合,得到其精确值.同时,利用快速傅里叶变换后的图像特征,实现端面图像中条纹方向的判定.实验中测得亚像素边缘点的定位精度为0.03像素,直线拟合精度为0.03像素,圆弧拟合精度为0.05像素,端面条纹判断的准确率为100%.实验结果表明:文中提出的检测方法能很好地满足贴片元件自动视觉检测稳定可靠、精度高及实时性强的要求.  相似文献   

10.
在纱线气圈动力学理论和环锭纺纱工艺基本原理基础上研究提出一种实用的确定气圈环合理尺寸的方法,为检验其可靠性,还采用不同尺寸气圈环进行了纺纱试验,并在此基础上对气圈环尺寸进行了优化设计。  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  相似文献   

15.
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。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
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.  相似文献   

18.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

19.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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