Preparation and characterization of novel ultra‐high molecular weight polyethylene composite fibers filled with nanosilica particles

Ultrahigh molecular weight polyethylene (UHMWPE)/nanosilica (F₂S_y) and UHMWPE/modified nanosilica (F₂S_mx‐y) as‐prepared fibers were prepared by spinning of F₂S_y and F₂S_mx‐y gel solutions, respectively. Modified nanosilica particles were prepared by grafting maleic anhydride grafted polyethylenes onto nanosilica particles. The achievable draw ratios (D_ra) of F₂S_y and F₂S_mx‐y as‐prepared fibers approached a maximal value as the original and modified nanosilica contents reached corresponding optimum values; the maximal D_ra value obtained for F₂S_mx‐y as‐prepared fiber specimens was significantly higher than that of the F₂S_y as‐prepared fiber specimens prepared at the optimum nanosilica content. The melting temperature and evaluated lamellar thickness values of F₂S_y and F₂S_mx‐y as‐prepared fiber series specimens decrease, but crystallinity values increase significantly, as their original and modified nanosilica contents respectively increase. Similar to the achievable drawing properties of the as‐prepared fibers, the orientation factor, tensile strength (σ_f) and initial modulus (E) values of both drawn F₂S_y and F₂S_mx‐y fiber series specimens with a fixed draw ratio reach a maximal value as the original and/or modified nanosilica contents approach the optimum values; the σ_f and E values of the drawn F₂S_mx‐y fiber specimens are significantly higher than those of the corresponding drawn F₂S_y fiber specimens prepared at the same draw ratios and nanosilica contents but without being modified. To understand the interesting ultradrawing, thermal, orientation and tensile properties of F₂S_y and F₂S_mx‐y fiber specimens, Fourier transform infrared, specific surface area and transmission electron microscopy analyses of the original and modified nanosilica were performed in this study. © 2012 Society of Chemical Industry     

试论陶瓷包装容器渗漏检测方法

通过对陶瓷包装容器渗漏检测方法的实验和研究,推荐存放法渗漏检测周期为20天较为合适,确认抽真空法是一种快速渗漏检测方法,建议选用509胶粘剂作为陶瓷包装容器的封口材料,认为渗漏值大于0.02g为有渗漏。     

High strength retention and dimensional stability of silicone/alumina composite panel under fire

Compact silicone/alumina composite was obtained by highly filling aluminum oxides and hydroxides in silicone resin. The flexural strength and dimensional change of the silicone/alumina composite after being fired has have been studied. It presented a special fire resistance, which could well coordinate the contradiction between the mechanical strength retention and the dimensional stability of silicone‐based composite in case of catching fire. Thermogravimetric analysis, scanning electron microscopy, X‐ray diffraction, transmission electron microscopy, and electron dispersion spectroscopy were applied to systematically explore the process of the in‐suit organic‐to‐inorganic transformation. A possible mechanism was proposed to illustrate the phenomenon of the high strength retention and dimensional stability of silicone/alumina composite under fire. Copyright © 2011 John Wiley & Sons, Ltd.     

样轴在液压仿形车床加工中的设计及应用

本文介绍了液压仿形车床在加工轴类零件过程中样轴的设计方法。结合实例讨论了样轴在设计过程中的轴向、径向尺寸及公差的确定,并且指出了样轴的正确使用方法。     

Prediction of Release Characteristics of Film‐Coated Urea from Structure Characterization Data of the Film

An efficient method for the prediction of the release characteristics of film‐coated urea from its film structure is proposed. A model spray‐coating apparatus was built to prepare a plane film to directly measure the film permeability coefficients by simulating the characteristics of randomness, intermittence and multiple layers of the coating, and eliminating particle collision effects. From analysis, the spray‐coated film structure can be modeled as comprising a dense structure and a defect structure. Both structures contributed to the penetration flux and the apparent permeability coefficients of the film for water and urea diffusion. The permeability coefficients of the plane films were calculated from the film structure model, and were shown to be close to the measured values.     

基于场景的空间投影估计和时域迭代非均匀性校正算法

本文提出了一种基于场景的空间投影估计和时域迭代非均匀性校正算法。本算法采用空间投影估计来估算图像的全局平移,并且在相邻帧之间进行时域迭代。具体分为下述三个主要步骤：首先,我们提出了一种基于配准准则的投影估计。然后,我们采用相邻帧的迭代校正来保证较快的收敛速度以及较少的非均匀性残留,同时保证基本没有鬼影。最终,我们将本算法移植到基于FPGA的硬件系统。通过评价标准测试了本算法的性能,并展示了在单调运动下系统非均匀性校正的实际效果。一段添加了模拟非均匀性的干净视频被用来对比此算法和阈值自适应最小均方差算法以及全偏差算法。在本文结尾,我们得到了结论,并对后期的工作进行了展望。     

一种中心多孔缺陷的保偏光子晶体光纤

探索了全反射型光子晶体光纤(PCF)中空气孔的排列形状和尺寸参 数与双折射之间的关系,通过结构优化设计出一种双折射为3.4×10－3且单模工作的二孔中心缺陷实芯PCF,并采用多元非线性回归拟合的方法得到了这 种PCF双折射的数值经验方程式,为保偏型PCF的研制提供了理论依据。     

分布式视频编码中基于多概率混合分布的相关噪声建模方法

相关噪声建模(Correlation Noise Modeling,CNM)的准确度是影响分布式视频编码(Distributed Video Coding,DVC)系统性能的关键因素之一.针对经过8×8离散余弦变换(Discrete Cosine Transform,DCT)后的相关噪声子带,本文提出了全新的基于多概率混合分布的CNM方法.该方法可根据子带的信息熵与子带在柯西、拉普拉斯和高斯三种概率分布下信息熵的相似度,自适应选择合适的概率分布对子带进行建模,提高了CNM的准确度.实验结果表明,采用本文提出的离线和在线CNM方法与现有典型的CNM方法相比,DVC系统的率失真(Rate-Distortion,R-D)性能均获得显著的提高.     

S Zorb装置生产国V汽油的实践

介绍了中国石化海南炼油化工有限公司S Zorb装置生产国V汽油时在操作上做出的调整及装置运行情况,指出了影响装置长期稳定生产国V汽油的主要因素和对策.通过调整操作和细化、强化吸附剂管理、严密监控再生器操作、提高关键设备的维护和管理水平等措施,装置分别经受住了超负荷运行、原料总硫大幅上升等情况的考验,能稳定生产硫质量分数不大于8 μg/g的国V汽油.期间原料硫质量分数平均为271 μg/g(最高达600μg/g),精制汽油RON损失小于0.9单位,抗爆指数损失小于0.5单位.证明装置能长期稳定生产超低硫含量的国V标准汽油.     

胶西北大尹格庄金矿床电解成矿机理及对找矿的启示

大尹格庄金矿床位于招平断裂带中段,矿床蚀变分带明显,大尹格庄断裂为一条导矿断裂,对矿体空间分布及侧伏具有明显的制约。蚀变岩岩石化学分析显示,黄铁绢英岩和绢英岩化碎裂岩中的Si有一部分来自钾长石化花岗岩,钾长石化花岗岩、绢英岩化碎裂岩和黄铁绢英岩中均有Fe、Mg、Mn的显著带入。在绢英岩化碎裂岩和黄铁绢英岩中普遍而显著聚集的元素还有Au、Ag、As、Mo、Bi、B、Ba、Rb、Sr等,在靠近招平断裂带的胶东群变质岩局部则有Mn、Co、Ni、Cr等元素的显著聚集。大尹格庄金矿床的电解成矿机理可以概括为:金矿体构成了"天然电解池"的阴极,在阴极附近发生的主要反应是SO2-4的还原与黄铁矿等硫化物矿物和自然金等金矿物的结晶反应,及绢英岩化水岩反应,以碳酸盐化和褐铁矿化为代表的蚀变岩构成了"天然电解池"的阳极。电解成矿机理有助于从一个新的视角认识胶西北蚀变岩型金矿床成矿作用及有关的找矿标志。