Video-based running water animation in Chinese painting style

This paper presents a novel algorithm for synthesizing animations of running water,such as water-falls and rivers,in the style of Chinese paintings,for applications such as cartoon making. All video frames are first registered in a common coordinate system,simultaneously segmenting the water from background and computing optical flow of the water. Taking artists’ advice into account,we produce a painting structure to guide painting of brush strokes. Flow lines are placed in the water following an analysis of variance of optical flow,to cause strokes to be drawn where the water is flowing smoothly,rather than in turbulent areas: this allows a few moving strokes to depict the trends of the water flows. A variety of brush strokes is then drawn using a template determined from real Chinese paintings. The novel contributions of this paper are:a method for painting structure generation for flows in videos,and a method for stroke placement,with the necessary temporal coherence.     

改善BP网络用于建立FCC产品收率预测模型过程中稀疏样本的训练或检验效果的研究

讨对BP（Back-propagation）人工神经网络用于FCC（Fluidcatalyticcracking）产品收率预测建模时稀疏点样本吻合性较差的问题，提出了①先对样本在空间用聚类分析法进行定位，确定那些是稀疏点、孤点和病点；②孤点用于训练；③剔除病点；④加大稀疏点对目标函数的权重改善稀疏点样本的吻合性，提高了模型的适应性和精度。     

Plane stress analysis for anisotropic no tension materials with hardening in compression

Mechanical behaviour of structural materials such as metamorphic or sedimentary rocks and block masonry assemblies is strongly influenced by intrinsic anisotropy. Directional effects of cleavage, bedding or mortar joints are quite dominant, as are those due to inelastic strains. Accounting for this feature and the low tensile strength an incremental elastic-plastic model with zero strength in tension and work-hardening in biaxial compression is proposed. This model is formulated on the basis of a linearized failure condition achieved either theoretically or experimentally and enjoys a simple hardening rule. Merits and limitations are discussed in view of numerical analysis.     

Temperature-programmed desorption of CO from Ni/SiO2 Application of analytic techniques for strongly interacting adsorbates

The interactions of CO with a Ni/SiO₂ catalyst were studied using the temperature-programmed desorption (TPD) technique. Programmed heating following adsorption led to desorption of both CO and CO₂. C and O were found to remain on the catalyst surface after TPD of CO; both were removed by subsequent H₂ treatment. Four CO desorption peaks, designated β^*, β₁, β₂, and β′, were assigned to a surface-type carbonyl, linear-bonded CO, bridge-bonded CO, and the recombination of C and O adatoms, respectively. CO₂ desorption spectra showed a single desorption peak, P₂, when the catalyst weight was low. A new chemical pathway, revealed by the appearance of another peak, P₁, was opened for a higher weight of sample. The formation of P₁ and P₂ followed first-order and second-order kinetics, respectively.The strong readsorption properties of CO within the catalyst bed have made direct determination of kinetic parameters difficult. In a limited range of temperatures, however, a similarity of the CO desorption spectra to results from unsupported Ni was found. Numerical simulation of the TPD process for a flow system has shown that the differential bed assumption is reasonable, i.e. a uniform distribution of the adsorbate within the bed during desorption is approximated. With these observations serving as a basis, the catalyst weight, the amount adsorbed, and the heating rate were varied to obtain desorption energies by analysis of the TPD data for both CO and CO₂.     

Solids suspension behaviour in profiled bottom and flat bottom mixing tanks

Solids suspension in the classical flat bottom mixing tank was analysed phenomenologically in detail. Abrupt re-direction of the flow in the centre and the periphery of the flat bottom tank gives rise to induced recirculation loops which account for the formation of central and peripheral fillets of unsuspended solids. The extent of these recirculation loops has a controlling influence on the attainment of complete off-bottom suspension in this tank geometry. Therefore the use of the complete off-bottom suspension condition in the flat bottom tank as the sole criterion for scale-up is likely to lead to scale-up parameters which do not represent the behaviour of the bulk of the tank.A fully profiled tank bottom and its approximation, a “cone and fillet” bottom design were used as alternative geometries to mitigate recirculation loops. Streamlining of the mixing tank substantially improved solid and suspension efficiency and also produced a more homogeneous hydrodynamic regime in the bottom zone of the tank. This latter effect potentially simplifies theoretical modelling of solids suspension and further justifies the preference for profiled bottom mixing tanks rather than the flat bottom tank.     

一种大型复杂构件加工新模式及新装备探讨

大型复杂构件是航空航天、能源、船舶等领域装备的核心结构件,此类构件通常具有尺寸大、形状复杂、刚性弱等特点。传统"分体离线加工-在线检测"模式存在工艺不稳定、过程复杂、柔性差、周期长等问题,以龙门式多轴数控机床加工为代表的"包容式"加工模式,难以适应大型复杂构件的高效高质量加工制造需求。提出一种基于移动式和吸附式机器人的多机协同原位加工新模式,通过多机器人系统自主寻位、精确定位加工与加工质量原位检测,实现大型复杂构件多安装面并行铣削、制孔与打磨等作业。多机器人系统包括移动式混联机器人、吸附式并联机器人、移动式串联铣削机器人、移动式双臂加工机器人和移动式打磨机器人。构建多机协同原位加工模式,需要揭示多机器人协同原位加工行为与大型弱刚性结构件质量控制的交互机理,面临着本体、测量、工艺和集成四个方面的挑战,需要设计高灵活、高刚度的移动式和吸附式加工机器人,解决移动机器人自主准确寻位和超大结构件原位高精检测难题,攻克加工变形误差在线补偿和振动抑制技术,通过集成实现多机协同高效高精加工,为大型复杂构件的高效高质量制造提供创新技术及装备,并实现此类构件制造核心技术及装备自主可控。     

逻辑内建自测试技术进展综述

逻辑内建自测试(logic buit-in self-test,LBIST)是一种可测试性设计技术,利用芯片、板级或系统上的部分电路测试数字逻辑电路本身。LBIST对于许多应用来说至关重要,尤其是国防、航空航天、自动驾驶等生命和任务关键型的应用。这些应用需要执行片上、板上或系统内自检,以提高整个系统的可靠性及执行远程诊断的能力。该文首先给出了常用的LBIST分类,并描述了经典的,也是工业界应用最成功的LBIST架构——使用多输入特征寄存器和并行移位序列产生器的自测试架构;其次,对国内外研究团队、研究进展进行了总结;再次,详细剖析了LBIST的基本原理、时序控制、确定性自测试设计、低功耗设计、“X”容忍等关键技术点,列举出了主流的LBIST商业工具,并逐一分析了其软件架构和技术特点;最后,讨论当前LBIST技术仍需进一步解决的问题,并进行展望。     

高温气冷堆氦气透平循环工质的热物性

在高温气冷堆氦气透平直接循环中,氦气既是堆芯的冷却剂,又是循环工质。氦气热物性数据来源多样且互相不一致,对目前应用较多的5种氦气热物性参数计算方法进行了比较分析。     

旋转气流控制激光切割硅钢新技术

针对目前激光切割工艺的缺点,提出采用氧辅助激光切割以降低所需激光切割功率,通过在工件底部加设旋风除渣器,形成旋转气流控制熔渣流向以去除熔渣的激光切割硅钢新技术。采用CO2激光器,对0.5 mm厚度硅钢片进行切割试验,试验结果表明,通过旋转气流主动控制,当气流处于层流状态时,可在较低激光切割功率时获得光滑的精细切口。利用有限元法对工件底部气流状况进行数值模拟,验证了旋转气流的工作规律,能为合理控制熔渣流向提供理论依据。