Aeroservoelastic model based active control for large civil aircraft

A modeling and control approach for an advanced configured large civil aircraft with aeroservoelasticity via the LQG method and control allocation is presented.Mathematical models and implementation issues for the multi-input/multi-output(MIMO) aeroservoelastic system simulation developed for a flexible wing with multi control surfaces are described.A fuzzy logic based optimization approach is employed to solve the constrained control allocation problem via intelligently adjusting the components of output v...     

管式固体氧化物燃料电池模型研究进展

管式结构是固体氧化物燃料电池一种重要结构类型,在设计和密封方面具有优势。近年来建模成为管式固体氧化物燃料电池研究的一种重要手段,已经发展出各种各样的模型。介绍了电化学模型、综合模型(同时耦合电化学、流动及传热)以及动态模型,比较各类模型优点和不足,指出有必要建立能同时从宏观和微观多层面多角度评价电池的全面模型。     

行波型超声马达的数学模型

简介了超声马达的结构和工作原理,针对超声马达结构特殊、机理复杂的特点,从控制的角度出发,采用系统辨识的方法,建立了行波型超声马达的三种数学模型,实验结果证实了模型的有效性。     

IGBT功率模块寿命预测的研究与设计

电子信息技术的发展极大的改进了人们的生产生活方式,具有饱和压降小,载流密度大等许多优点的功率器件IGBT,在超高电压电力传输、新能源的开发利用等方面获得广泛应用。然而其工作在电压高、电流强、状态切换频繁等复杂环境中。这就导致其容易损耗,使模块寿命大大降低。目前,国内外在IGBT功率模块寿命研究领域已经取得了一定的成绩。本文在介绍了IGBT结构的基础上通过建模对其寿命预测进行了研究并具体阐述了功率循环中叠加效应、任务曲线、雨流计数法。     

多点地质统计学算法Snesim参数敏感性分析

Snesim是第一个被应用到油田储层建模中的多点地质统计学算法。文中以弯曲河道作训练图像,对该算法建模过程中常涉及到的参数(如目标边际分布与伺服系统参数、搜索半径与搜索角、旋转角与仿射率,以及多重网格层数等)进行敏感性分析。分析结果表明:当目标相比例值与训练图像边际概率值接近时,模拟结果较合理;增大伺服系统参数可使模拟结果的边际概率接近目标相比例,但伺服系统参数设置过高将降低河道连续性;搜索邻域应与模拟维度相适应;局部旋转角和仿射率可将训练图像中的平稳与非平稳信息融合起来,用于趋势模拟;多重网格模拟中,网格层数取决于最大尺度结构信息的大小。以上认识可为利用Snesim算法进行储层建模提供一定的指导。     

Soft error susceptibility mapping of DRAMs using a high-energy nuclear microprobe

Soft errors in 16 Mbit dynamic random access memories (DRAMs) have been investigated using proton microprobes at 400 keV with a spot size of 1 × 1 μm². The newly developed susceptibility mapping can reveal the correlation between the particle hit-position position and the susceptibility to soft errors in a DRAM. The cell-mode soft-errors were found to take place by the incidence of ions within 6 μm around a monitored cell. These errors would be induced by minority carrier diffusion in a lateral direction. This result manifests the possibility of multiple-bit errors by the incidence of an energetic particle.     

Preparation of (Pb0.88La0.12)TiO3 thin films for dynamic random access memory by low pressure-metalorganic chemical vapor deposition

La-modified lead titanate (PLT) thin films were prepared by hot-wall type low pressure-metalorganic chemical vapor deposition method. Pb(dpm)₂, La(dpm)₃, and titanium tetraisopropoxide were used as source materials. The films were deposited at 500°C under the low pressure of 1000 mTorr and then annealed at 650°C for 10 min in oxygen ambient. Sputter-deposited platinum electrodes and 180 nm thick PLT thin films were employed to form MIM capacitors with the best combination of high charge storage density (26.7 μC/cm² at 3V) and low leakage current density (1.5 × 10^-7 A/cm² at 3V). The measured dielectric constant and dielectric loss were 1000∼1200 and 0.06∼0.07 at zero bias and 100 kHz, respectively.     

Status and application of HgCdTe device modeling

In this article, device modeling refers to numerical simulation of semiconductor device physics to predict electrical behavior. The silicon integrated circuit industry provides the example for the use of technology computer-aided design to simulate wafer fabrication processes, and the electrical performance of devices and circuits. This paper first reviews semiconductor device modeling in general, then as applied in work supporting the development and analysis of HgCdTe infrared detectors. Example applications of one- and two-dimensional device modeling are simulation of a bias-selectable, integrated two-color detector, and two-dimensional effects on the spectral response of a HgCdTe detector with composition grading.     

Bitumen-water interfacial tension modeling by using subtractive clustering method

Calculation of interfacial tension during bitumen production is a crucial issue in heavy crude oil history. Upon variation in pressure, temperature and phases composition, interfacial tension between bitumen and water change. In this work a sophisticated method called subtractive clustering was utilized to predict dynamic interfacial tension between bitumen and water. The subtractive clustering method is composed of optimized fuzzy logic algorithm. A data bank which is collected from open-source literature, is used to create a reliable model. Then the prediction accuracy of the measured dynamic interfacial tension using subtractive clustering have been examined. Results state that the comparison of measured interfacial tension and predicted interfacial tension indicate acceptable accuracy of proposed model. Also more than 90 percent of data points have less than 3 percent absolute error.     

模型正演技术在叠前深度偏移中的应用

川西龙门山前缘构造非常复杂,逆掩推覆构造带构造形变强烈,构造幅度大,地层倾角陡,断块发育,地震波场复杂,速度横向变化大,常规叠后时间偏移处理成像效果较差.利用已有地震资料解释成果,建立地质模型进行射线追踪正演模拟分析,从而指导叠前深度偏移初始速度模型的建立,达到了复杂地表下复杂构造精确成像的目的.事实证明,这种将模型正演应用于叠前深度偏移处理成像的方法对于提高地震资料处理的成像质量具有非常重要的作用.