A new model for springback prediction in which the Bauschinger effect is considered

Springback prediction is an important issue for the sheet metal forming industry. Most sheet metal elements undergo a complicated cyclical deformation history during the forming process. For an accurate prediction of springback, the Bauschinger effect must be considered to determine accurately the internal stress distribution within the sheet metal after deformation. Based on the foundations for isotropic hardening and kinematic hardening, Mroz multiple surface model, plane strain assumptions, and experimental observations, a new incremental method and hardening model is proposed in this paper. This new model compares well with the experimental results for aluminum sheet metal undergoing multiple-bending processes. As is well known, aluminum is one of the most difficult sheet metals to simulate. The new hardening model proposed in this paper is not only a generic model for springback prediction but also a hardening model for sheet metal forming process simulation.     

氮化硅反应烧结设备PLC自动控制

本文通过对氮化硅反应烧结设备的可编程控制，说明可编程控制技术是材料学科的一个重要应用方向。     

Low gate interface traps AlGaN/GaN HEMTs using a lattice matched ZrZnO transparent gate design

AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MIS-HEMTs) using a radio-frequency magnetron sputtered ZrZnO transparent oxide layer as a gate insulator are investigated and compared with traditional GaN HEMTs. A negligible hysteresis voltage shift in the C–V curves is seen, from 0.09 V to 0.36 V, as the thickness of ZrZnO films increases. The composition of ZrZnO at different annealing temperatures is observed using X-ray photoelectron spectroscopy (XPS). The ZrZnO thin film achieves good thermal stability after 600 °C, 700 °C and 800 °C post-deposition annealing (PDA) because of its high binding energy. Based on the interface trap density analysis, D_it has a value of 2.663 × 10¹² cm⁻²/eV for 10-nm-thick ZrZnO-gate HEMTs and demonstrates better interlayer characteristics, which results in a better slopes for the I_ds degradation (5.75 × 10⁻¹ mA/mm K⁻¹) for operation from 77 K to 300 K. The 10-nm-thick ZrZnO-gate device also exhibits a flat and a stable 1/f noise, as V_GS–V_th, and at various operating temperatures. Therefore, ZrZnO has good potential for use as the transparent film for a gate insulator that improves the GaN-based FET threshold voltage and improves the number of surface defects at various operating temperatures.     

实用加解扰系统

介绍一个由４种视频基带加扰模式组成的数字加扰系统，具有很高的保密性。而系统的解扰可以由低成本的模拟解扰器完成。     

Growth of a single-wall carbon nanotube film and its patterning as an n-type field effect transistor device using an integrated circuit compatible process

This study presents the synthesis of a dense single-wall carbon nanotube (SWNT) network on a silicon substrate using alcohol as the source gas. The nanosize catalysts required are made by the reduction of metal compounds in ethanol. The key point in spreading the nanoparticles on the substrate, so that the SWNT network can be grown over the entire wafer, is making the substrate surface hydrophilic. This SWNT network is so dense that it can be treated like a thin film. Methods of patterning this SWNT film with integrated circuit compatible processes are presented and discussed for the first time in the literature. Finally, fabrication and characteristic measurements of a field effect transistor (FET) using this SWNT film are also demonstrated. This FET is shown to have better electronic properties than any other kind of thin film transistor. This thin film with good electronic properties can be readily applied in the processing of many other SWNT electronic devices.     

An effectiveness trial of a dissonance-based eating disorder prevention program for high-risk adolescent girls.

Efficacy trials indicate that an eating disorder prevention program involving dissonance-inducing activities that decrease thin-ideal internalization reduces risk for current and future eating pathology, yet it is unclear whether this program produces effects under real-world conditions. The present effectiveness trial tested whether this program produced effects when school staff recruit participants and deliver the intervention. Adolescent girls with body image concerns (N = 306; M age = 15.7, SD = 1.1) randomized to the dissonance intervention showed significantly greater decreases in thin-ideal internalization, body dissatisfaction, dieting attempts, and eating disorder symptoms from pretest to posttest than did those assigned to a psychoeducational brochure control condition, with the effects for body dissatisfaction, dieting, and eating disorder symptoms persisting through 1-year follow-up. Effects were slightly smaller than those observed in a prior efficacy trial, suggesting that this program is effective under real-world conditions, but that facilitator selection, training, and supervision could be improved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On multicast flow control for heterogeneous receivers

In this paper, we study the impact of heterogeneous receivers on the throughput of multicast flow control and propose a new multicast flow control algorithm to optimally partition group members into multiple subgroups. Our main contributions are as follows. First, we cast the multicast flow control problem in the Internet as the list partition problem and then prove that the list partition problem is equivalent to the optimal paging problem in cellular networks. The result is not only interesting in itself but also essential to derive the first known analytical bounds for the throughput of multicast flow control. Furthermore, we propose an algorithm to solve not only the list partition problem but also the optimal paging problem and the problem of bulk data transfer using multiple multicast groups. The complexity of our algorithm is one order less than the best known algorithm designed only for the problem of bulk data transfer using multiple multicast groups in the literature. While earlier work uses simulations to justify the usage of multiple subgroups to deliver information to a large amount of receivers in heterogeneous networks, we provide the first analytical support     

An iterative facility layout algorithm

In this paper we present a facility layout algorithm that iterates between a genetic algorithm with a slicing tree representation and a mixed-integer program with a subset of the binary variables set via the genetic algorithm. The genetic algorithm is very good at finding low-cost solutions while maintaining shape constraints on the departments. The slicing tree representation and the mixed-integer program are compatible in terms of layout representation, with the mixed-integer program representation more general. The mixed-integer program allows us to relax the last remaining constraints of the slicing tree representation of the genetic algorithm. We present our genetic algorithm and the iterative algorithm, while illustrating their performance on test problems from the literature. In 10 of the 12 problems, new lower best-cost solutions are found.