Pi-coefficient analysis of update algorithms for adaptive systems

This paper finds the appropriate pi-coefficients for a parameter estimation adaptive system and uses them to analyze the stability of two estimation algorithms. The estimation error dynamics of the system are modeled by a linear time-invariant subsystem and a nonlinear time-varying update law in a feedback loop. Then the so-called max-p problems are formulated and solved to obtain the pi-coefficients for the linear subsystem and nonlinear update low. For the investigated system, the quantitative results show that the least-squares update algorithm has larger stability range than that of the gradient algorithm, and the σ-modification scheme gives larger stability ranges for both algorithms.     

综合应用地震属性、测井数据反演储层参数

本文研究了样点地震属性的特征提取，利用BP神经网络建立测井声波时差和地震属性的非线性映射关系。采用距离加权平均对研究区所有井的反演结果进行外推。为了提高分辨率和计算结果的准确性，详细分析、研究了适合于地震信号分解和重构的小波，以及测井声波时差和地震波阻抗与层界面的关系。最后，对反演的声波时差资料进行界面影响校正，进而计算出较符合实际情况的孔隙率参数。经已知井和新钻井验证，计算结果和实际情况相一致，效果令人满意。     

彩色PDP用玻璃基板

本文讨论了彩色ＰＤＰ现用钠钙玻璃的热稳定性，指出由于这种玻璃在热处理过程中易变形和收缩，因而不适合作大面积彩色ＰＤＰ基板材料，介绍了彩色ＰＤＰ基板玻璃的制造方法和特点。最后介绍了日本旭硝子公司和美国康宁公司各自为彩色ＰＤＰ新开发的玻璃基板材料ＰＤ２００和ＣＳ２５。     

矩形板压电振子振动有限元分析

利用有限元法，对具有四个凸起的矩形板压电振子的振动状态进行了解析计算，并根据其振动特点，重新选择结构参数制作了超声矩形板马达，结果大大提高了这种马达的转速和效率等性能。     

NUMERICAL MODEL FOR DYNAMIC SIMULATION OF TRAFFIC FLOW

ＮＵＭＥＲＩＣＡＬＭＯＤＥＬＦＯＲＤＹＮＡＭＩＣＳＩＭＵＬＡＴＩＯＮＯＦＴＲＡＦＦＩＣＦＬＯＷＷｕＺｈｅｎｇ；ＺｅｎｇＬｉ－ｎｏｎｇ（ＤｅｐａｒｔｍｅｎｔＡｐｐｌｉｅｄＭｅｃｈａｎｉｃｓ，ＦｕｄａｎＵｎｉｖｅｒｓｉｔｙ，Ｓｈａｇｈａｉ２００４３３，Ｐ...     

用小尺寸R－CT试样研究核压力容器钢断裂韧性及与Charpy试样的比较

提出了一种用双边带深侧槽的小尺寸圆形紧凑拉伸试样评定核压力容器（ＲＰＶ）钢断裂韧性的单试作试验方法，给出了用该方法测定的两个厂家生产的核压力容器用Ａ５０８ＣＬ３钢的断裂韧性参数，还与Ｃｈａｒｐｙ试样的试验结果及大尺寸标准试样的试验结果进行了比较。研究结果表明：用双边带深侧槽的小尺寸Ｒ－ＣＴ试样测得的断裂韧性值比相同恻槽深度预制疲劳裂纹Ｃｈａｒｐｙ试样的测试值更接近有效断裂韧性值，所以，用于核压力容器断裂韧性的监测是可行的。     

FE Simulation for Internal Inversion of Aluminium Alloy Tube

1 Introduction A double-walled invertube is difficult to fabricate other than applying inversion process. Such kind of invertube can be used as impact energy absorbing element in transport vehicles, like aircrafts and automobiles. Reddy T Y[1] did the analysis of Internal inversion and calculated the inversion load. Reid[2] et al. examined nosing and internal inversion of cold drawn steel tube by the finite element package ABAQUS. Recently, Rosa P A[3] et al. investigated Internal invers…     

Investigation of texture effect on visual colour difference evaluation

The texture effect on visual colour difference evaluation was investigated in this study. Five colour centers were selected and textured colour pairs were generated using scanned textile woven fabrics and colour‐mapping technique. The textured and solid colour pairs were then displayed on a characterized cathode ray tube (CRT) monitor for colour difference evaluation. The colour difference values for the pairs with texture patterns are equal to 5.0 CIELAB units in lightness direction. The texture level was represented by the half‐width of histogram, which is called texture strength in this study. High correlation was found between texture strength and visual colour difference for textured colour pairs, which indicates that an increasing of 10 units of texture strength in luminance would cause a decreasing of 0.25 units visual difference for the five colour centers. The ratio of visual difference between textured and solid colour pairs also indicates a high parametric effect of texture. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 341–347, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.     

矿用扁平接链环静态电测实验及有限元分析

对φ30的矿用扁平接链环进行静态拉伸电测实验，分析并得出产生最大强度的位置。同时应用ANSYS有限元分析软件对接链环的力学简化模型进行分析，与实验结果相比较，有助于找出齿部破坏规律，对齿形的改进及今后的疲劳分析具有重要意义。