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1.
基于三次B样条小波构造曲线的优点,生成新的汉字字形.它首先将字形轮廓线转换成B样条曲线,用小波变换分解曲线的控制点为不同层次的细节与低层次控制点(曲线),这些细节代表汉字字形的某些特征,改变某些层次上的细节,通过小波变换中的合成过程恢复字形,能得到一种新字形.  相似文献   

2.
一般三次B样条交互插值的一种局部表示法   总被引:1,自引:0,他引:1  
交互插值三次B样条曲线曲面在辅助几何设计中使用很多,但控制点和特值点之间的变化关系一直是讨论的关键,本就一般三次B样条曲线交互性插值中控制点和插值点之间的关系进行了讨论,并提出了一个实用的局部表示法来实现曲线的交互插值。  相似文献   

3.
针对激光切割矢量汉字中出现的问题,提出了用参数三次B样条曲线优化逼近矢量汉字的局部轮廓.在优化逼近过程中,应用Taylor级数展开法进行B样条曲线的参数优化,反复拟合得到优化的参数值.使在误差允许的范围内,获得用B样条曲线优化逼近的汉字轮廓.处理后的矢量汉字字形光顺,生成的数控程序短.  相似文献   

4.
用B样条曲线优化逼近矢量汉字   总被引:1,自引:1,他引:1  
针对激光切割矢量汉字中出现的问题,提出了用参数三次B样条曲线优化逼近矢量汉字的局中轮廓,在优化逼近过程中,应用了Taylor级数展开法进行了B样条曲线的参数优化,反复拟合得到优化的参数值,使在误差允许的范围内,获得用B样条曲线优化逼近的汉字轮廓,处理后的矢量汉字字我顺,生成的烽控程序短。  相似文献   

5.
分析了某种带局部形状调整参数的B样条曲线的构造,提出用带调整参数的变换矩阵方法生成控制点进而生成所要求的带形状参数的三次B样条曲线的方法.研究了参数变化对曲线的影响,以及该方法下所生成样条曲线在拼接点处的连续性条件.  相似文献   

6.
提出一上B样条曲线升阶的新方法,该算法可以用于任何均匀和非均匀的B样条曲线的升阶。当曲线升阶次t≥1时,节点和控制点的个数可以受到控制而不发迹曲线的形状。  相似文献   

7.
对三次B-样条基函数进行分析,给出三次B-样条曲线非整体性的一些特点,以及在工程曲线设计中的具体应用.  相似文献   

8.
本文简述了三次B样条曲线及其性质特点,总结了用TURBO C实现计算机动画的几种常用方法,指出了用三次B样条实现动画设计的控制技巧,并给出了一个用三次B样条来生成动画图案的案例。  相似文献   

9.
3次准均匀B样条曲线是曲线曲面重构中广泛应用的算法,逆向工程要求用尽可能少的数据点实现曲线曲面的高精度重构。本文将3次均匀B样条曲线的性质推广到3次准均匀B样条中,并对推论进行了证明。基于所得的推论,提出一种改进的3次准均匀B样条逼近曲线算法。所提出的方法不用反算控制点,可以使曲线插值于控制点;引入切向参数S和曲率参数L对控制点处的切向特性和曲率特性进行控制和调整;可以通过调整形状参数提高曲线的拟合精度。最后,使用三种方法对某叶片截面离散数据重构,结果证明,所提出的方法在使用相同的控制点时,拟合误差更小;在达到相同的逼近精度时,使用的控制点数更少。  相似文献   

10.
三次B样条因其控形能力强,具有变差减少性和c2连续性,故在自由曲线和曲面设计中获得广泛的应用.但若将其用于插值,则常导致出现不希望的拐点和振荡.无振荡均匀B样条插值法通过在需要控制曲线切线或曲面参数曲线的切线的地方增加辅助控制点,就可以达到良好的消除振荡的效果,且保留了均匀三次B样条的全部优点,并得以很自然地在曲线中插入直线段或在曲面中插入平面片  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.
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   

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.
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   

15.
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.  相似文献   

16.
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   

17.
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.  相似文献   

18.
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   

19.
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   

20.
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.  相似文献   

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