Shear-induced crystallization of poly(phenylene sulfide)

The crystalline morphology of poly(phenylene sulfide) (PPS) isothermally crystallized from the melt under shear has been observed by polarized optical microscope (POM) equipped with a CSS450 hot-stage. The shish–kebab-like fibrillar crystal structure is formed at a higher shear rate or for a longer shear time, which is ascribed to the tight aggregation of numerous oriented nuclei in the direction of shear. The crystallization induction time of PPS decreases with the shear time, indicating that the shear accelerates the formation of stable crystal nuclei. Under shear, the increase of spherulite growth rate results from highly oriented chains. The melting behavior of shear-induced crystallized PPS performed by differential scanning calorimetry (DSC) shows multiple melting peaks. The lower melting peak corresponds to melting of imperfect crystal, and the degree of crystal perfection decreases as the shear rate increases. The higher melting peak is related to the orientation of molecular chains. These oriented molecular chains form the orientation nuclei which have higher thermal stability than the kebab-like lamellae that are developed later. A new model based on the above observation has been proposed to explain the mechanism of shish–kebab-like fibrillar crystal formation under shear flow.     

pH and salt responsive poly(N,N-dimethylaminoethyl methacrylate) cylindrical brushes and their quaternized derivatives

We present the synthesis and characterization of poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) cylindrical brushes, their pH responsiveness, and the corresponding quaternized analog, poly{[2-(methacryloyloxy)ethyl] trimethylammonium iodide} (PMETAI) brushes. PDMAEMA brushes were prepared by atom transfer radical polymerization (ATRP) using the grafting-from strategy. Initiating efficiencies of the ATRP processes were determined by cleaving the side-chains and gel permeation chromatography (GPC) analysis. Due to the slow initiation and steric hindrance, the initiating efficiency is only around 50%. The PDMAEMA brushes show worm-like structures and pH responsiveness, as proven by dynamic light scattering (DLS), atomic force microscopy (AFM), and cryogenic transmission electron microscopy (cryo-TEM) measurements. Strong cationic polyelectrolyte PMETAI brushes were produced by quaternization of the PDMAEMA brushes. AFM and cryo-TEM images showed similar worm-like morphologies for the PMETAI brushes. The PMETAI brushes collapsed in solution with high concentration of monovalent salt, as proven by DLS and AFM results.     

Dual band-notched ultra-wideband microstrip antenna using asymmetrical spurlines

A simple and novel ultra-wideband microstrip-fed antenna with dual band-notched characteristic is presented. By etching a pair of asymmetrical spurlines on the feedline, two notched bands of 600 MHz (3.95? 4.55 GHz) and 650 MHz (5.35?6.0 GHz) are achieved. Measured results show that this antenna operates from 2.5 to 12.0 GHz for voltage standing wave ratio less than 2, except two frequency notched bands of 3.95?4.55 GHz and 5.35?6.0 GHz. Moreover, this antenna has good omnidirectional radiation patterns in the H-plane.     

双柱塞砂浆泵中工作机构的设计和仿真研究

本文介绍了双柱塞砂浆泵的工作原理，根据机构替代原理建立起双柱塞砂浆泵工作机构的运动分析模型，然后在MatLab环境下，详细介绍了工作凸轮曲线的设计程序，利用计算机设计程序可以方便地分析工作缸活塞以及工作凸轮机构的位移、速度、加速度，利用SIMULINK仿真工具箱进行运动学仿真，为工作机构设计提供相应的理论分析依据。     

钢包炉(LF)预熔精炼渣的研究

预熔精炼渣具有成分均匀，性能稳定，储存时不吸水等特点，钢包炉中使用预熔精炼渣时成渣均匀且速度快，具有较强的吸附钢中非金属夹杂的能力。综合脱硫率高等冶金效果。有显著净化钢液作用。     

Composite group vector space method for estimating melting and boiling point of pure organic compound

Composition Group Vector Space (CGVS) method for estimating melting and boiling point T _m , T _b of organic compound has been proposed, and the principle of this method has been elucidated. The models for estimating T _m , T _b have been established and the numerical values of relative parameters have been presented. The average percentage deviations of T _m , T _b estimation are 7.53 and 1.58, respectively, which show that the present method demonstrates significant improvement in applicability to predict the above properties, compared to conventional group methods.     

Do 9-month-old infants expect distinct words to refer to kinds?

In 3 experiments, 9-month-old infants' expectations for what distinct count noun labels refer to were investigated. In Experiment 1, a box was opened to reveal 2 objects inside during familiarization: either 2 identical objects or 2 different objects. Test trials followed the same procedure, except before the box was opened, the contents were described using 2 distinct labels ("I see a wug! I see a dak!") or the same label twice ("I see a zav! I see a zav!"). Infants who heard a label repeated twice looked longer at 2 different objects versus 2 identical objects, whereas infants who heard 2 distinct labels showed a different pattern of looking. Experiments 2 and 3 presented infants with object pairs that only differed in shape or color, and it was found that infants expected the different-shaped (but not the different-colored) objects to be labeled by distinct count nouns. Because the property of shape is a cue to kind membership and the property of color is not, these results suggest that even at the beginning of word learning, infants may expect distinct labels to refer to distinct kinds of objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

化学模式识别法在钢铁工业中的若干应用

本文涉及一种崭新的非函数数据处理法及其在工业诊断和优化中的应用。并对其进行要因分析和优化决策的原理作了介绍。结合钢铁工业生产中的实例进行了分析。还探讨了该方法在钢铁工业中应用的意义。