共查询到19条相似文献,搜索用时 265 毫秒
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柔性版印刷加网技术研究 总被引:3,自引:2,他引:1
传统的加网技术已经不能满足现代柔性版精细印刷的要求,新的加网技术应运而生.简要介绍了调幅加网、调频加网和混合加网技术,比较分析了不同加网技术的特点,分析了传统柔性版印刷加网工艺的不足,介绍了现代柔性版加网新技术并指出在应用中存在的问题,对柔印加网新技术进行了展望. 相似文献
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数字加网新技术的研究进展 总被引:14,自引:14,他引:0
综述了近年来数字加网技术的研究现状,阐述了超细胞结构加网、调频加网和混合加网的原理,并对其特点进行了分析.在此基础上,指出了数字加网技术应用中存在的主要问题,展望了数字加网未来的研究方向. 相似文献
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分析了Sublima混合加网技术的3个特点:采用了21μm的网点实现1%~99%网点的还原;以2400dpi的输出精度实现340lpi的加网;消除了由调幅网点向调频网点过渡的痕迹.通过对采用Sublima混合加网技术和ABS调幅加网技术印制出的印刷样张的技术对比,证明了在相同的印刷条件下,Sublima混合加网技术的应用可增大印刷网点色彩再现范围,提升印刷质量.最后指出了混合加网将是未来加网技术发展的主要方向之一. 相似文献
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对现有调频加网技术在实际生产中的应用进行分析,总结其规律,比较调幅和调频两种加网方式的区别,探索调频加网技术在现有CTP制版条件下的质量控制方法,对规范化数据化的调频加网制版、印刷工艺有指导意义。 相似文献
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数字印刷中调频加网线数对印刷质量的影响 总被引:2,自引:2,他引:0
目前数字印刷加网多采用调频加网,介绍了一个改变加网线数从而影响印刷输出效果的实验,分析了调频加网线数如何影响数字印刷图像质量,以及提高数字印刷图像输出设备输出精度的必要性. 相似文献
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Vernotte F 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2002,49(4):508-513
It is well-known that low frequency noises (flicker FM and random walk FM) are not stationary; it is not possible to define either the mean value or the (true) variance. Therefore, the use of a stationary approach yields convergence problems unless a low cut-off frequency is introduced, the physical meaning of which is not clear. The moment condition explains the link between insensitivity to drifts and convergence for low frequency noises in a stationary approach. This condition may be summarized by the following consideration: the divergence effect of a low frequency noise for the lowest frequencies induces a false drift with random drift coefficients; the lower the low cut-off frequency, the higher the variance of the coefficients of this drift. These variances may be known by theoretical calculations. The order of the drift is directly linked to the power law of the noise. The moment condition is demonstrated and applied for creating new estimators (new variances) and for simulating low frequency noises with a very low cut-off frequency. 相似文献
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在喷墨打印机喷出墨滴大小可变时,以Clapper-Yule模型为基础,研究了可变墨滴喷墨打印印刷品的反射率预测模型。首先引入了墨滴大小变化和Clapper-Yule模型的调频加网形式;然后,用墨滴变化引起的墨层厚度变化和调频网点大小的变化扩展Clapper-Yule模型;最后,建立了墨滴大小扩展的Clapper-Yule模型,并通过模拟实验验证了模型的优越性。 相似文献
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《IEEE transactions on instrumentation and measurement》1979,28(1):3-5
The power spectra for FM signal modulated by the smoothed random telegraph signal are examined experimentally. These FM signals are the noises of variable bandwidth with power spectrum distributions in Gaussian, rectangular, or concave forms; these forms being determined by the values of the product of the mean number of zero-crossings per second of the random telegraph signal and the time constant of a low-pass RC filter driven by the random telegraph signal. 相似文献
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Jian Wang Kaspars Berzins Diana Hicks Julia Melkers Fang Xiao Diogo Pinheiro 《Scientometrics》2012,93(2):391-411
This paper proposes a method for classifying true papers of a set of focal scientists and false papers of homonymous authors in bibliometric research processes. It directly addresses the issue of identifying papers that are not associated (??false??) with a given author. The proposed method has four steps: name and affiliation filtering, similarity score construction, author screening, and boosted trees classification. In this methodological paper we calculate error rates for our technique. Therefore, we needed to ascertain the correct attribution of each paper. To do this we constructed a small dataset of 4,253 papers allegedly belonging to a random sample of 100 authors. We apply the boosted trees algorithm to classify papers of authors with total false rate no higher than 30% (i.e. 3,862 papers of 91 authors). A one-run experiment achieves a testing misclassification error 0.55%, testing recall 99.84%, and testing precision 99.60%. A 50-run experiment shows that the median of testing classification error is 0.78% and mean 0.75%. Among the 90 authors in the testing set (one author only appeared in the training set), the algorithm successfully reduces the false rate to zero for 86 authors and misclassifies just one or two papers for each of the remaining four authors. 相似文献
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We propose a Monte Carlo method to obtain the thermodynamic functions of Ising systems. We perform a random sampling of spin configurations to determine the degeneracy of the energies of the system, from which an approximant to the partition function is determined. The main advantage of the method over conventional Metropolis lies in the fact that only a single Monte Carlo run is needed to obtain results valid for all temperatures, magnetic fields, and coupling parameters (FM or AFM). As an illustration of the method, we present results for the Ising model in a magnetic field on a 8x8 lattice. The method can be adapted to tackle the random field Ising model (RFIM), the dilute Ising model, and the Ising spin glass, in any spatial dimension. 相似文献
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为解决总体平均经验模态分解(Ensemble Empirical Mode Decomposition, EEMD)中虚假IMF分量过多问题,提出了一种基于频率截止的EEMD方法。该方法采用一种新的IMF筛分终止条件--以信号自身的最小频率为EMD分解IMF分量的截止频率;然后将基于频率截止的IMF筛分终止条件引入EEMD分解。通过仿真和实测信号分析,并与EMD、EEMD分解结果比较得到,运用频率截止的EEMD方法不仅有效减少了虚假IMF分量的产生,使得分解的目的性更加明确,而且保证了EEMD分解出的IMF分量的完备性,更好地抑制了模态混叠现象。 相似文献