Sliding-friction electrification of polymers and charge decay

Linear low-density polyethylene (LLDPE) and polypropylene (PP) were charged by sliding under a cylindrical aluminium contact. The surface charge accumulation on the polymer films was time dependent, and a function of the sliding velocity, metal contact force, and film type. The surface potential increased linearly with velocity in the range 0.33–0.75 m/s, and showed a square-root dependence on the contact force up to 6.5 N. Thermally stimulated charge decay (TSCD) studies showed longer charge lifetimes in samples friction-charged on one side than in corona-charged samples. Friction charging creates deeper near-surface traps than are normally present in the polymers. Charge stability is further imporved by simultaneously friction charging both surfaces of the films, increasing the half-value charge decay temperature (T_1/2) by 27°C and 37°C over that in corona-charged samples (i.e., to 98°C and 120°C for LLDPE and PP, respectively). These monopolarity electrets should prove useful in charge storage devices.     

基于核优化密度聚类的绿色苹果分割算法

苹果的可见光谱目标的高效、精准识别是实现果园测产或机器自动采摘作业的关键,由于绿色目标果实与枝叶背景颜色较为相近,因此绿色苹果的识别成为新的挑战。再由于果园实际复杂环境因素影响,如光照、阴雨、枝叶遮挡、目标重叠等情况,现有的目标果实识别方案难以满足测产或自动采摘的实时、精准作业需求。为更好地实现果园自然环境中绿色目标果实识别问题,提出一种新的核密度估计优化的聚类分割算法（kernel density clustering, KDC）。新算法首先利用简单的迭代聚类（simple linear iterative cluster, SLIC）算法将目标图像分割成不规则块,集结小区域内近似像素点组成超像素区域,计算单元由像素点转变为超像素区域,有效降低数据复杂度,且SLIC算法简化图像数据时可有效避免目标果实轮廓模糊;基于超像素构造R-B区域均值和G-B区域均值的二维特征分量,建立针对聚类分析的青苹果颜色特征空间。然后借助密度峰值聚类中心计算绿色苹果图像每个数据点的局部密度和局部差异度,为解决分割边界模糊问题,在计算过程中利用核密度估计计算局部密度,确保局部密度在不同复杂场景中的清晰准确表达,以更精准找出被低密度区域分割的高密度区域,实现任意形状的聚类。最后以局部密度和距离构造寻找聚类中心的决策图,该研究采用双排序算法实现聚类中心的自动选择,完成目标果实的高效分割。新算法通过SLIC算法获得图像的超像素区域表示,数据点的局部密度通过核密度估计得到,大幅降低算法的计算量,实现目标图像的高效、精准分割。为更好地验证新算法性能,实验采集多光照、阴雨等环境下的遮挡、重叠等复杂目标图像,以分割效率、分割有效性、假阳性、假阴性等指标进行评价,通过对比k-means聚类算法、meanshift聚类算法、FCM算法和DPCA算法,该研究提出的新算法分割性能均最优。     

关于Orlicz凸体的收敛性的注(英文)

本文研究了Orlicz投影体和Orlicz质心体的性质.利用几何分析的方法,获得了Orlicz投影算子和Orlicz质心算子的连续性.     

Non-invasive detection of superimposed latent fingerprints and inter-ridge trace evidence by infrared spectroscopic imaging

Current latent print and trace evidence collecting technologies are usually invasive and can be destructive to the original deposits. We describe a non-invasive vibrational spectroscopic approach that yields latent fingerprints that are overlaid on top of one another or that may contain trace evidence that needs to be distinguished from the print. Because of the variation in the chemical composition distribution within the fingerprint, we demonstrate that linear unmixing applied to the spectral content of the data can be used to provide images that reveal superimposed fingerprints. In addition, we demonstrate that the chemical composition of the trace evidence located in the region of the print can potentially be identified by its infrared spectrum. Thus, trace evidence found at a crime scene that previously could not be directly related to an individual, now has the potential to be directly related by its presence in the individual-identifying fingerprints. A portion of this work was presented at the 16th Meeting of the International Association of Forensic Sciences, Montpellier, France September 2–7, 2002.     

Dipole effects and the work functions of the single crystal LaB6

Both the interior dipole structure normal to the polar surface of a crystal and any dipole layer at the surface itself contribute to the surface work function. For LaB₆, the structures of the unreconstructed (100), (110) and (111) faces or the reconstructions believed to characterize the (110) and (111) surfaces would produce dipole layers and differences in work function among these surfaces which are at least an order of magnitude greater than the differences which have been measured. Modification in ionic charge at sites making up the outermost surface dipole layers can markedly affect the dipole contribution to the work functions and it is argued that such charge modification may occur as a general phenomenon in ionic crystals.     

Quantum Mechanics is Incomplete but it is Consistent with Locality

Quantum mechanics is seen to be incomplete not because it cannot explain the correlations that characterize entanglement without invoking either non-locality or realism, both of which, despite special relativity or no-go theorems, are at least conceivable. Quantum mechanics is incomplete, in a perhaps broader than hidden variable sense, because it fails to address within its theoretical structure the question of how even a single particle, by being in a given quantum state, causes the frequency distribution of measurement values specified by the state. This incompleteness of quantum mechanics as it is currently conceived is both fundamental and indefeasible. Failure to address the question of how the states of entangled particles are given effect to yield the correlations they specify is simply a particular albeit attention arresting instance of this incompleteness. But if that is so then quantum mechanics cannot be held to be inconsistent with locality.