CE/SE方法在点火管一维两相流数值计算中的应用

介绍了CE／SE方法。该方法不同于以往的一些计算格式，在计算中它把时间和空间同等对待，具有格式构造简单、计算方便和对激波间断分辨率高等优点。运用适合点火管一维两相流控制方程的CE／SE方法来计算点火管内的一维两相流流动，源项采用四阶Runge-Kutta方法进行处理。数值计算的结果与实验数据的比较表明，CE／SE方法能对两相流进行有效的数值模拟。     

Realization of nth-order series impedance function using only (n-1) current-feedback amplifiers

A new configuration for realizing a higher-order series impedance function using current-feedback amplifiers (CFAs) is presented. The nth-order series impedance function employs only (n–1) CFAs and (2n–1) passive elements. The higher order series impedance function can be applied to realize various higher-order highpass and lowpass filters. The passive element values can be easily decided from the coefficients of the filter transfer functions. The use of CFAs simplifies the circuit implementation and makes the proposed circuit attractive for application. Experiments and simulation results are given to confirm the theoretical analysis.     

Accurate model of arbitrary wire antennas in free space, above orinside ground

An accurate model of wire antennas in free space, above or inside lossy ground is presented in which the current is assumed to flow on the surface of the wire and the testing is also performed on the surface. To replace the traditional delta-gap source, a more accurate source model is developed by using the Huygens' principle. From this principle and reciprocity theorem, a variational formulation of the input admittance is derived. When the triangle function is chosen as both basis and weighting functions, all the elements of impedance matrix and source vector are formulated in closed forms, which can be rapidly computed. Several numerical results are given. Comparing with measured data, both the current distribution and input impedance by this model are more accurate than those of delta-gap model     

Minimum time control of conductive heating systems formicroelectronics processing

A minimum time control scheme is designed to improve repeatability by minimizing the loading effects induced by the common processing condition of placement of a semiconductor wafer at ambient temperature on a large thermal-mass bake plate at processing temperature. The minimum time control strategy provides an optimal solution for minimizing the worst case deviation from a nominal temperature set-point during the load disturbance condition. This results in a predictive controller that performs a predetermined heating sequence prior to the arrival of the wafer as part of the resulting feedforward/feedback strategy to eliminate the load disturbance. The controller is easy to design and implement and makes it more suitable for online implementation such as automatic online tuning of a feedforward controller. Experimental results depict an order-of-magnitude improvement in the settling time and the integral-square temperature error between the optimal predictive controller and a feedback controller for a typical load disturbance     

ATM网络中VBR复用器的硬件实现

提出了一种用于ＡＴＭ网络中ＶＢＲ业务的复用器设计方案,探讨了如何将一种基于令牌 桶控制的ＵＰＣ算法用于ＡＴＭ统计复用器的信源接入控制,并用“在系统编程技术”加以硬件实现。     

Physical parameters extraction from current–voltage characteristic for diodes using multiple nonlinear regression analysis

In this work, the two-step iteration combined with the nonlinear multiple regression technique to extract physical parameters for diodes, using a simple physical-based current–voltage (I–V) model is demonstrated. This statistical method can be applied for sampling for a wide variety of diodes including light-emitting diodes (LEDs) and Schottky diodes. Our results show the technique is an accurate and systematic approach for extracting diode parameters. The calculated recombination currents indicate the recombination efficiency for LEDs and the quality for Schottky diodes.     

不同功率氮激光穴位照射镇痛作用研究

作者以不同功率的氮澈光对大白鼠分组进行穴位照射。照射前后测痛，照射后动物痛阈都有提高，说明不同功率的氮激光均有镇痛作用。高、低功率氮澈光穴位照射后动物产生的痛阈变化经统计学处理，差异性不显著。提示使用低功率氮激光同样可达提高痛阈的目的。     

Estimation of High-Frequency Currents From Near-Field Scan Measurements

High-frequency currents on the pins of integrated circuits (ICs) and on printed circuit board (PCB) traces are needed to predict and analyze electromagnetic interference in high-speed devices. These currents can, however, be difficult to measure when traces are buried within the PCB or chip-package, especially when several current-carrying traces are in close proximity. Techniques for estimating high-frequency currents from near-field scan data are proposed in this paper. These techniques are applied to find currents on the pins of an IC, on traces buried beneath other traces in a PCB, and on traces over a slot in the ground plane. Methods of dealing with the ill-posed nature of the current-estimation problem are discussed, as are applications to electrically large structures. A study of the sensitivity of the technique to errors in the measured fields, errors in the circuit geometry, and errors in the estimated dielectric constant of the PCB or chip package show that, for reasonable errors in these parameters, currents can be estimated to within an average of 20% (1.6 dB) or less of their correct values.     

A Linear Phase Condition for Volterra Filters

In linear finite-impulse-response filter design, it is desirable that the filter frequency response has linear phase (LP). In this brief, we investigate the LP concept for nonlinear Volterra filters. The LP condition of Volterra filters is defined in terms of its output spectrum in which the phase term introduced by the Volterra kernels is linear. It is shown that under certain symmetry conditions, the LP condition is satisfied by Volterra filters. Moreover, the LP condition for Volterra filters can be considered as an extension to the linear filter case.     

Tailored and Highly Stretchable Sensor Prepared by Crosslinking an Enhanced 3D Printed UV-Curable Sacrificial Mold

Taking advantage of unlimited geometry design, 3D printed sacrificial mold cast with highly conductive polymer composites is used to prepare a sensor with designed structures. However, the disposal of the mold in a mild condition while the refined structures can be maintained is still a challenge. Herein, a bifunctional monomer hydrolyzable hindered urea acrylate is synthesized to create a cross-linked polymer network, preventing the dissolution of printed parts in the uncured resin. 3D printed scaffolds can be hydrolyzed in hot water, which provides an attractive option for sacrificial molds. Also, a porous flexible strain sensor (PFSS) is fabricated by casting polyurethane/carbon nanotubes composites into the sacrificial molds, which demonstrates a high stretchability (≈510%) and an excellent recoverability. Meantime, the pressure sensitivity (0.111 kPa⁻¹) and a long-term electrical resistance of PFSS is characterized. The resistance response signal remains nearly unchanged after 100 compressive loading cycles at a large strain of 60%. Benefiting from the design freedom of 3D printing, a practical application of the PFSS with a complex and customized structure to monitor human motion is demonstrated. These results prove that the sacrificial molding process has great potential for user-specific stretchable wearable devices.