Mechanical properties of titanium connectors

The tensile mechanical properties of welded titanium joints were studied, and intact titanium was used as controls. Welded joints were fabricated with either a stereographic laser-welding technique or a gas tungsten arc welding technique. The effect of heat treatment following a simulated porcelain application was also investigated. Heat-treated laser welds had significantly lower ultimate tensile strengths. Heat treatment had no effect on the modulus of elasticity or elongation, but generally significantly decreased the yield strength of the titanium specimens. The gas tungsten are welding specimens had significantly higher yield strengths and elastic moduli than the other two groups. The elongation of the control specimens was significantly greater than the elongation of the gas tungsten arc welding specimens, which was in turn significantly higher than that of the laser-welded specimens.     

激光瞬间作用后金属表层特性及机理研究

本文讨论了强激光瞬间作用金属表面后金属表层特性的改变。分析和实验得出，通过控制入射激光功率密度和作用时间可以实现相交硬化及快速熔化——凝固处理。指出利用脉冲激光并选择适当的工艺参数可以有效地对金属工件进行表面处理以改进其硬度、耐磨及耐腐蚀等性能。     

Semantic segmentation and summarization of music: methods based on tonality and recurrent structure

This paper describes a study on automatic music segmentation and summarization from audio signals. The paper inquires scientifically into the nature of human perception of music and offers a practical solution to difficult problems of machine intelligence for automated multimedia content analysis and information retrieval. Specifically, three problems are addressed: segmentation based on tonality analysis, segmentation based on recurrent structural analysis, and summarization. Experimental results are evaluated quantitatively, demonstrating the promise of the proposed methods     

Room temperature near-infrared tunable Cr:La3Ga5SiO14 laser

Laser operation was achieved in a Cr-doped crystal of La₃ Ga₅SiO₁₄. The laser had a free-running wavelength of 960 nm at room temperature from 862 to 1107 nm. Up to 80 mW output power has been measured with 1.5 W of pump power absorbed from a krypton ion laser. The ⁴T₂ fluorescence spectrum showed a peak at 890 nm indicating an unusually large Franck-Condon shift. At room temperature the fluorescence lifetime was 5.3 μs and the fluorescence quantum yield was measured to be about 14%     

电气传动控制系统新一簇——开关磁阻电机调速系统

本文介绍了开关磁阻电机调速系统的国内外发展概况以及该系统驱动电源电路种类和控制装置的发展方向。通过将该系统与直流电动机和鼠笼式异步电动机调速系统的比较,提出了一种实用的以单片机为核心的开关磁阻电机调速系统。     

地震岩性横向变化的划分——自回归模式识别的应用

假设地震记录道可视为一个离散的时间序列,并认为它是一个包含各种信息的高维样本空间,利用自回归模式识别方法,在信息量损失最小的条件下,求取样本空间的特征系数,可使维数大大降低,按层计算出所有地震道的特征系数,利用多种距离准则,在层内对它们进行划分.对划分出的各部分利用模糊聚类方法进行聚类,实现了层内岩性横向变化的划分和分类.用理论模型对本方法进行了验证,并将它应用于实际地震剖面处理,获得了满意的效果.     

Identification for systems with bounded noise

In this paper, we present a set-membership identification algorithm for systems with unknown but bounded disturbance. The algorithm contains a weighting factor which is selected according to whether the new observed data contains sufficient information. The proposed approach ensures that the estimation error is bounded and nonincreasing. Furthermore, it is shown that the parameter estimates provided by the algorithm will converge to a region containing the true parameters, and its upper bound is also given     

Ultrastructural characteristics of Lyme disease spirochetes (Borrelia burgdorferi) isolated from Ixodes persulcatus in China

Diluting composite materials with unfilled resin to facilitate clinical application during direct lamination will result in an alteration of filler loading with possible changes of physical properties. This study compared the surface hardness and abrasion resistance of a visible light-cured microfilled and hybrid resin with and without dilution. Samples were prepared, cured, and stored in distilled water at 37 degrees C for 24 hours before testing. Knoop hardness values were obtained from the upper surface of 10 samples in three dilution and control groups of each material. Three samples of the dilution and control groups were similarly prepared and stored for toothbrush abrasion testing. Data from the hardness and abrasion tests were subjected to analysis of variance and Tukey's test at a 0.05 level of significance. Results showed that dilution had a significant effect on surface hardness of the materials tested, although the diluted materials were not significantly different from the controls. Abrasion tests showed visible evidence of abrasion on all samples, but dilution showed no significant effect on abrasion resistance of the materials tested.     

修正容积法确定稠油蒸汽吞吐开发的合理井距

方法 应用计算油气进质储量计算方法－－容积法、对实际采油量及最科采油油量进行脱气原油体积收缩量校正。目的 确定和评价蒸汽吞吐开发的合理井距。结果 该方法综合考虑了蒸汽吞吐降压开采过程中溶解气油比和原油体积系数的变化，可确定不同蒸汽吞吐开发阶段的合理井距。结论修正容积法确定稠油蒸汽吞吐开发的合理吉距具有参数取简便，计算简单的特点，与井距研究的其它该当具有可靠性及有效性。     

RP2基因的连锁分析定位

为寻找视网膜色素变性相关基因ＲＰ２所在的染色体位点，采用染色体ＸＰ２１．１－Ｐ１１．２区段的８个微卫星ＤＮＡ樯记。，对Ｘ－连锁ＲＰ家系进行连锁分析。