Effect of fiber orientation on the structural behavior of FRP wrapped concrete cylinders

In this study, 27 concrete cylinders with a diameter of 152.4 and a height of 304.8 mm were prepared. Among them, 18 cylinders were wrapped using two layers of fiber reinforced polymer (FRP) with six fiber orientations; six cylinders were wrapped using four layers of FRP with fibers in axial or hoop direction only; the remaining three cylinders were used as control. The FRP used was E-glass fiber reinforced ultraviolet (UV) curing vinyl ester. Fifteen coupon specimens were prepared to experimentally determine the tensile strength of the FRP with fibers oriented at 0°, 45°, and 90° from the loading direction. Co-axial compression tests were conducted on the wrapped cylinders and control cylinders. The test results were compared with existing confinement models. It is found that the strength, ductility, and failure mode of FRP wrapped concrete cylinders depend on the fiber orientation and wall thickness. Fibers oriented at a certain angle in between the hoop direction and axial direction may result in strength lower than fibers along hoop or axial direction. A larger database is desired in order to refine the existing design-oriented confinement models.     

Determination of J–R curves of thermoplastic starch composites containing crossed quasi-unidirectional flax fiber reinforcement

Thermoplastic starch (MaterBi) composites reinforced with quasi-unidirectional flax fiber in cross-ply (CP) arrangement were produced by film stacking followed by hot pressing. These composites, containing various amount of flax, failed ductilely with pronounced crack growth. Therefore, to determine their fracture mechanical behaviour the J-integral resistance curve concept (J–R) was applied. As the crack growth could not be traced, attempt was made to use the located acoustic emission (AE) events for that purpose. It was established that weighting and smoothing the located cumulative AE amplitudes the crack path can be correctly reconstructed. This was proved by collating the AE results with those derived from infrared thermographic (IT) inspection. Knowing the crack propagation at each point of the force–displacement curves the J–R curves could be determined. Both critical or initiation J-integral and tearing modulus went through a minimum with increase of flax content in the composites.     

基于块缺失图像修复技术的研究与应用

图像修复是数字图像处理的重要内容，在图像润色、视频图像复原等诸多领域都有着非常广泛的应用。该文以对图像块粗糙度的分析为依据，优化纹理合成算法，并结合JPEG算法，应用于图像压缩，使图像压缩率得到显著提高。     

Perspectives of probabilistic inferences: Reinforcement learning and an adaptive network compared.

The assumption that people possess a strategy repertoire for inferences has been raised repeatedly. The strategy selection learning theory specifies how people select strategies from this repertoire. The theory assumes that individuals select strategies proportional to their subjective expectations of how well the strategies solve particular problems; such expectations are assumed to be updated by reinforcement learning. The theory is compared with an adaptive network model that assumes people make inferences by integrating information according to a connectionist network. The network's weights are modified by error correction learning. The theories were tested against each other in 2 experimental studies. Study 1 showed that people substantially improved their inferences through feedback, which was appropriately predicted by the strategy selection learning theory. Study 2 examined a dynamic environment in which the strategies' performances changed. In this situation a quick adaptation to the new situation was not observed; rather, individuals got stuck on the strategy they had successfully applied previously. This "inertia effect" was most strongly predicted by the strategy selection learning theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于多Agent的并行Q-学习算法

提出了一种多Agent并行Q-学习算法．学习系统中存在多个Agent，它们的学习环境、学习任务及自身功能均相同，在每个学习周期内，各个Agent在各自独立的学习环境中进行学习，当一个学习周期结束后，对各个Agent的学习结果进行融合，融合后的结果被所有的Agent共享，并以此为基础进行下一个周期的学习．实验结果表明了该方法的可行性和有效性。     

基于强化学习的股票预测系统的研究与设计

股票市场是金融分析领域中重要而困难的问题。股票数据的分析和预测具有重大的理论意义和诱人的应用价值。BP神经网络在目前的股票预测系统中应用广泛,但是作为有导师的学习系统,BP神经网络必须要求提供相关的经验数据才能正常运行。对此本文提出了一种基于强化学习BP算法应用于股票预测系统,通过强化学习体系来实现体统的自学习,通过网络集成来达到初始数据的预处理,提高系统的泛化能力,在实际应用中取的较好的效果。     

活性绢云母在聚乙烯中增强作用的研究

利用绢云母的基本特性，对其进行超音速气流粉碎及表面化学改性，改变绢云母鳞片性质，制备出聚乙烯增强剂．研究结果有利于非金属矿物深加工、树脂基复合材料等研究．     

A Comparison of Voucher-Delivery Schedules for the Initiation of Cocaine Abstinence.

Studies on the use of shaping procedures to increase rates of cocaine abstinence have produced promising results. This study used a Brief Abstinence Test to examine the impact of reinforcement for initial reductions in cocaine use on a subsequent abstinence reinforcement test. Methadone maintenance patients showing evidence of cocaine use were exposed to two 1-week reinforcement conditions. During the shaping condition, participants could earn $50 vouchers on Wednesday and Friday for meeting quantitative urinalysis criteria and a $100 voucher on the following Monday for meeting the more stringent qualitative criteria. During the terminal condition, only the $100 earning opportunity for meeting the qualitative criteria was provided. Participants were more likely to meet the qualitative reinforcement criteria on Wednesday and Friday in the shaping condition than in the terminal condition. However, contrary to the initial hypothesis, the shaping reinforcement condition did not increase rates of abstinence on the final abstinence test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

应用AFS—930型双道原子荧光光度计联合测定水中的砷和硒

本文采用原子荧光光谱法,研究了联合测定水样中砷和硒的技术。用10%盐酸和1%硫脲-1%抗坏血酸混合试剂处理样品,并以2.0%硼氢化钾和0.5%氢氧化钠为还原剂,在5%的盐酸介质测定砷和硒。砷和硒的检出限分别为:0.20μg/L和0.13μg/L,本方法具有操作简便、快速、基体干扰少、灵敏度高等优点,可用于水样中砷和硒的联合测定。     

概念加固思想及工程应用

提出了工程结构加固中新的思路——概念加固。概念加固是运用人的思维和判断，从宏观上决定工程加固中的基本问题、基本概念及基本原则，并阐述了基于“概念加固”思想指导下的整体预应力加固技术，介绍了在工程加固中的应用实例。