Analysis of the central cavity of axisymmetric forward extrusion by the upper bound approach

In this paper, the use of a kinematically admissible velocity field to predict the presence of a central cavity in the final stage of axisymmetric forward extrusion is advanced, in accordance with the results of Moire experiments. On the basis of the velocity field, the critical condition for central cavity formation is obtained by the upper bound approach. Furthermore, the quantitative relationships between central cavity formation and process parameters (reduction in area, frictional factors on the ram and chamber wall, relative residual thickness of the of the billet) are studied. The results show that (1) the critical relative residual thickness of the billet used for the central cavity formation is affected primarily by the reduction in area and the frictional factors on the ram, and slightly by the frictional factor on the chamber wall; (2) the relative dimensions of the central cavity increase with a decrease in the relative residual thickness of the billet; (3) the growth rate of the central cavity decreases with an increase in the frictional factors on the ram, but is affected by the frictional factors on the chamber wall only slightly. Good correlation is found between the analytical and experimental results.     

玻璃纤维毡增强热塑性复合片材的研制和应用

本文简要介绍了玻璃纤维毡增强聚丙烯片材的研制，性能和应用。     

打火机专用SAN树脂工业化开发生产

介绍了15kt/a本体苯乙烯－丙烯腈（SAN)装置试生产打火机专用SAN树脂的生产情况，确定了主要工艺配方及参数：进料组成为乙苯浓度为6％－11％、丙烯腈浓度为30％－42％，聚合温度130－145℃、压力0．40－0．46MPa，搅拌转速60－90r/min，脱挥温度215－250℃、压力小于等于4kPa；并对影响打火机志用SAN树脂性能的主要工艺条件及因素进行了讨论。结果表明，聚合温度、结合丙烯腈含量、熔体流动指数、转化率是影响打火机专用SAN树脂生产工艺及产品性能的主要因素。     

细胞激动素Kinetin合成的改进

介绍了用糠胺与腺嘌呤在催化条件下反应合成细胞激动素kinetin,该法原料易得,反应条件温和,产品收率及纯度都较高。     

Discourse cues to deception in the case of multiple receivers

Behavioral cues to deception are instrumental in detecting deception. As one of the primary sources of deception behavior, text has been analyzed at the level of sub-sentence or message but not the discourse of interaction. Additionally, empirical studies on cues to deception in the case of multiple receivers remain nonexistent. To fill these voids, we propose a discourse framework and six hypotheses about deception behaviors in a multi-receiver environment. The deception behaviors are operationalized by discourse features based on an analysis of real-world data. The results of statistical analysis validate the efficacy of discourse features in discriminating deceivers from truth-tellers.     

Point-based online value iteration algorithm in large POMDP

Partially observable Markov decision process (POMDP) is an ideal framework for sequential decision-making under uncertainty in stochastic domains. However, it is notoriously computationally intractable to solving POMDP in real-time system. In order to address this problem, this paper proposes a point-based online value iteration (PBOVI) algorithm which involves performing value backup at specific reachable belief points, rather than over the entire belief simplex, to speed up computation processes, exploits branch-and-bound pruning approach to prune the AND/OR tree of belief states online, and proposes a novel idea to reuse the belief states that have been searched to avoid repeated computation. The experiment and simulation results show that the proposed algorithm can simultaneously satisfy the requirement of low errors and high timeliness in real-time system.     

Collaborative representation with reduced residual for face recognition

Collaboration representation-based classification (CRC) was proposed as an alternative approach to the sparse representation method with similar efficiency. The CRC is essentially a competition scheme for the training samples to compete with each other in representing the test sample, and the training class with the minimum representation residual from the test sample wins the competition in the classification. However, the representation error is usually calculated based on the Euclidean distance between a test sample and the weighted sum of all the same-class samples. This paper exploits alternative methods of calculating the representation error in the CRC methods to reduce the representation residual in a more optimal way, so that the sample classes compete with each other in a closer range to represent the test sample. A large number of face recognition experiments on three face image databases show that the CRC methods with optimized presentation residual achieve better performance than the original CRC, and the maximum improvement in classification accuracy is up to 12 %.     

Water-soluble and amphiphilic polymers

Summary Three PEO-PSt-PEO triblock polymers and their parent ho-nopolystyrene have been studied by means of light scattering technique in chloroform, toluene and ethyl acetate. It has been found that the weight average molecular weights calculated by using the equation Mapp- were unbelievable negative values; and the largest deviation appeared for the sample with PEO mole content of about 50%. Data of PSt-PEO-PSt triblock polymers in literature have been quoted and discussed.     

ATO包裹硅酸锆的制备与应用

采用化学共沉淀技术制备了锑掺杂二氧化锡(ATO)包裹硅酸锆的导电粉体,对比了该导电粉体与ATO在防静电陶瓷中的应用效果。结果表明与掺纯ATO相比较,掺入ATO包裹硅酸锆的防静电陶瓷颜色比较浅,并且能明显减少氧化锡的用量,当陶瓷的表面电阻为107Ω/□量级时,用ATO包裹硅酸锆作为导电填料可以节省25%左右的ATO。     

炭分子筛概述

阐述了炭分子筛分离的原理，并分别从其制备原料、制备方法、产品用途等方面综述了近年来炭分子筛的新进展。