活齿端面谐波齿轮啮合状态的几何模型

活齿端面谐波齿轮是综合现有的谐波齿轮传动和活齿传动的优点而发明的一种新型传动装置．可以在保留现有谐波齿轮传动所有优点的基础上．大幅度地提高所传递的功率。建立了描写活齿端面谐波齿轮啮合状态的几何模型．并利用该几何模型推导出了活齿端面谐波齿轮实现连续传动的条件。     

TEM study on precipitation and transformation of secondary carbides in 16Cr–1Mo–1Cu white iron subjected to subcritical treatment

High chromium white irons solidify with a substantially austenitic matrix supersaturated with chromium and carbon. The subcritical heat treatment can destabilize the austenite by precipitating chromium-rich secondary carbides and other special carbides. In the as-cast condition the eutectic carbides are (Fe,Cr)₇C₃ and (Fe_4.3Cr_2.5Mo_0.1)C₃. The initial secondary carbide precipitated is (Fe,Cr)₂₃C₆ after heat-treating at 853 K for 10 h. There are MoC, Fe₂MoC and -carbide precipitating, and (Fe,Cr)₂₃C₆ transforms to M₃C after 16 h at 853 K. The -carbide and (Fe,Cr)₂₃C₆ accomplish transformation to M₃C and the matrix changes from martensitic to pearlitic after 22 h at 853 K. Thereby, in the subcritical heat treatment process, the initial secondary carbide precipitated is (Fe,Cr)₂₃C₆, followed by -carbide, MoC and Fe₂MoC. In addition, there are two in situ transformations from (Fe,Cr)₂₃C₆ and -carbide to M₃C carbides.     

Effects of Rare Earth and Alkaline Earth on Spheroidizing of Eutectic Carbides in Low Tungsten White Cast Iron

Tungsten Alloy White Cast Iron(TAWCI) has great brittleness and narrow application scope. The influences of Rare earth element(Ce) and alkaline earth elements ( K, Na) on the microstructures and performances of TAWCI were researched, and the idea estimating spheroidizing effect of carbides using Circular Degree (C. D) were put forward. The result shows that eutectics carbide tums into sphericity from network after modification, and carbide is refined and uniformly distributed and the C. D of eutectic carbide increases. The mechanism of carbide spheroidizing was analyzed. The impact toughness and wear resistance of TAWCI obviously improve with the rise of C. D of carbides.The service life of modified TAWCI roll is 35 % higher than that of high chromium cast iron roll, and its production cost is reduced by 25 %.     

A novel bistable reflective display using quick‐response liquid powder

Abstract— We have developed new powder materials that exhibit liquid behavior, which can lead to the realization of novel bistable and reflective displays having paper‐white appearance, high contrast, and quick response. Two types of display were demonstrated, one had 160 × 160 array of pixels and the other had 320 × 320 in a 3.1‐in.‐diagonal viewable image size corresponding to 66 and 132 dpi, respectively. These displays were driven by passive‐matrix addressing. The displays showed a reflectivity of more than 41%, a contrast more than 1:10, and a pixel response time of less than 0.2 msec. The seven‐segment display for use in clocks was also demonstrated.     

具有未知系统偏差的自适应Kalman平滑器

提出一种有效的具有未知系统伯差的自适应Ｋａｌｍａｎ平滑器．应用状态空间方法和ＡＲＭＡ新息模型，基于白噪声估值器和输出预报器，给出线性离散定常系统自适应最优状态和偏差联合Ｋａｌｍａｕ平滑器，最后给出仿真实例．     

有色噪声激发下结构随机振动离散分析方法

本文以线性结构体系在白噪声激发下随机振动离散分析方法为基础,对线性结构体系在有色噪声激发下的随机振动离散分析方法进行了研究。给出均值、均方响应的离散递推式.并为了能在计算机上进行实际运算,给出了实用化计算公式,最后用该方法对一结构进行了实际计算,分析了计算结果。     

NURBS体参数化模型的无支撑打印算法

处理大角度悬垂结构的打印问题是无支撑打印的主要挑战。针对NURBS（non-uniform rational Bspline）体参数化模型的多自由度无支撑三维打印技术,提出一种锥形切片算法。通过对模型的三维文件进行几何映射,利用水平切片算法对其进行切片,得到模型变形后的连续打印路径G-code;然后对得到的G-code进行逆映射,生成适用于六轴机械臂的多自由度连续打印路径。利用锥形切片算法规划打印路径,可以在无须支撑的情况下,依靠自支撑结构实现对悬空结构部分的打印。最后,通过仿真实验和对比实验,验证了锥形切片算法的准确性、可行性和有效性。锥形切片算法的引入为NURBS体参数化模型的无支撑三维打印提供了一种更加高效、经济和环保的解决方案。     

物探在白岭铜锌矿床勘探中的应用效果

白岭铜锌矿床位于近接触带部位,断裂构造及围岩蚀变发育,地球物理异常十分明显。应用高精度磁测、激电中梯和测 深等物探方法,在白岭铜锌矿床进行综合勘查,结果显示出了较好的地质找矿效果,说明高磁、激电等物探异常对圈定矿体位置和产状、缩短勘探周期具有重要的指导意义。     

Applications of power series in computational geometry

A number of algorithms are presented for obtaining power series expansions of curves and surfaces at a point. Some results on the radius of convergence are given. Two applications of series are given:

1. • for curve tracing algorithms, where a truncated series is used to approximate the curve of intersection of two surfaces

2. • to define nth degree geometric continuity, for arbitrary

Bezier曲面的Hermite方法

基于Kirov定理,研究带有附加导数条件的Bezier曲(线)面。该方法可以在每个型值点再给出导数条件,因此与通常的Bezier曲面拟合相比,有更多的自由度,但其拟合曲面的次数仅比Bezier曲面高一次。这一方法有助于CAGD领域的工程人员采用Bezier技术达到控制所设计曲面形状的目的。