苯乙烯-马来酸酐共聚物增容Nylon-6/ABS共混体系的形态和力学性能

通过熔融共混法制备了苯乙烯-马来酸酐共聚物(SMA)增容的尼龙6(Nylon-6)/ABS共混物.采用TEM、SEM、FTIR等研究了SMA增容的Nylon-6/ABS共混物的相形态与性能.发现在Nylon-6和ABS的简单共混体系中,分散相易聚集,相界面清晰,断裂面光滑,呈脆性断裂,相容性差.加入少量SMA后,共混物由共连续相结构转变为典型的"海-岛"结构,分散相分布均匀,界面粘接程度增加,表明SMA对Nylon-6/ABS体系有显著的增容效果.     

Influence of fused deposition modeling parameters on the mechanical properties of ABS parts

This work aims to determine the influence of fused deposition modeling (FDM) printing parameters on the mechanical properties of parts fabricated on an Ultimaker2 printer with acrylonitrile butadiene styrene (ABS). The effect of several parameters such as interlayer cooling time (ILCT), nozzle diameter, infill density, raster angle and layer thickness on the ultimate tensile strength, yield strength, and elastic modulus of produced parts was evaluated. Two independent studies were conducted: a first study dedicated to the ILCT and a second study where the influence of other parameters was evaluated through a design of experiments (DoE) approach. Both studies were carried out through the execution of standard tensile tests. The statistical analysis of tensile tests results was processed with the ANOVA methodology. The obtained results indicate that a reduced ILCT improves the tensile strength of parts. It is shown that nozzle diameter and infill density are the parameters that most influence the mechanical properties of ABS, with the upper range selected values improving the studied mechanical properties. The raster angle configuration of (?45^o/45^o) benefits UTS and yield strength of ABS samples. Interactions of nozzle diameter on layer thickness were detected. It was observed that smaller layer thickness promotes a higher elastic modulus and UTS; however, for thinner layers (0.06‐0.10 mm), no significant differences were found on strength of samples due to potential high distortion levels.     

第二代氨合成催化体系——钌系氨合成催化剂及其工业应用*

本文综述了第二代氨合成催化体系——钌系氨合成催化剂的研制、开发及工业应用情况。介绍了钌系氨合成催化剂的载体、促进剂、钌活性前身物对氨合成催化活性的影响。比较了钌系氨合成催化剂与铁系氨合成催化剂的反应机理与性能特点。新型氨合成催化工艺流程的成功开发为钌系氨合成催化剂的工业应用提供了有力的保障。     

烷基苯磺酸盐型表面活性剂的HPLC及HPCE分离分析进展*

作为一种常见的表面活性剂,烷基苯碘酸盐（ABS）被广泛用于许多领域。本文结合作者最近的研究结果,对烷基苯磺酸盐表面活性剂的HPLC及HPCE分离分析现状及其应用前景进行了综述。     

计算机磁头／磁盘超薄气膜润滑压强的算子分裂算法

以任意拉森数的超薄气体润滑方程为基础，采用算子分裂法和非结构三角网格的有限元法计算Ω型磁头的空气轴承气垫面(ABS)气膜压强分布、气浮力和纵倾力矩；在分析比较流量系数的各种算法的基础上，确定采用多项式拟合数据库计算流量系数．计算结果表明：采用算子分裂法可以有效克服在高轴承数时的数值不稳定性，消除数值振荡；在小轴承数时，气浮力随轴承数增加而增大，当轴承数增大到某一数值后，气浮力趋近某一稳定值，此时气膜压强分布与磁头造型基本一致；气膜的纵倾力矩在轴承数的某一临界值附近出现最大值．     

基于MIPS平台的 MPEG-4 AACplus v2解码器的实现

介绍了MPEG-4 AACplus v2解码器的基本原理和MIPS平台HTK HSB1101的原理与应用,给出了MPEG-4 AACplus v2解码器在MIPS平台HTK HSB1101上的实现方案。在保证解码质量和实时解码要求的情况下,结合HTKHSB1101平台的特性,对解码器在软件代码和处理器方面进行了优化。实验结果表明,与标准算法相比,该解码器在确保音频解码质量的同时,提高了解码速度,满足了解码实时性要求,也为视频解码和其他应用提供了足够的处理空间。     

基于绝对值差的归一化波形匹配混合算法

基于归一化的波形匹配算法运用十分广泛,但缺点是运算量大。为此提出一种基于绝对值差的归一化混合算法。该算法先将原始波形分解成三层,在每一层分别采用改良的绝对值差法、改良的序列相似性法、归一化互相关法进行匹配,最终实现精确匹配。实验表明,这种混合算法比归一化互相关法在波形匹配速度上有了大幅度的提高。     

新型陶瓷刀具材料JX－2－I界面结构的实验研究

利用ＴＥＭ和电子衍射图谱分析，研究了新型陶瓷刀具材料ＪＸ－２－Ｉ的界面微观结构。ＴＥＭ分析表明，ＪＸ－２－Ｉ刀具材料的界面结合状态较好，Ａｌ＿２Ｏ＿３／ＳｉＣｗ界面上形成了具有较高强度的“钢筋混凝土”结构，在Ａｌ＿２Ｏ＿３／ＳｉＣｗ和Ａｌ＿２Ｏ＿３／ＳｉＣｐ界面上没有剧烈的化学反应发生；通过ＴＥＭ和电子衍射图分析，发现在Ａｌ＿２Ｏ＿３的晶粒边界上有尖晶石（ＭｇＡｌ＿２Ｏ＿４）生成，这有利于控制Ａｌ＿２Ｏ＿３晶粒的长大，提高复合材料的强度。     

先进战机多功能相控阵系统综合射频隐身技术

射频隐身是未来先进战机隐身要求的重要方面，研究机载电子设备、尤其天线系统的射频隐身技术是现实的和迫切的；特殊设计的相控阵系统能够同时担负雷达、电子战和高速数据链等各种战术任务，是未来先进战机不可或缺的重要电子装备。文中从相控阵天线系统的辐射特性与LPI、散射特性与LO和战术任务规划等方面论述了实现多功能相控阵系统射频隐身的技术方向，理清研究的先后层次，指出未来研究的发展方向。     

Photooxidation of glycated and non‐glycated phosphatidylethanolamines monitored by mass spectrometry

Phosphatidylethanolamines (PE) are one of the major components of cells membranes, namely in skin and in retina, that are continuously exposed to solar UV radiation being major targets of photooxidation damage. In addition, due to the presence of the free amine group, PE can also undergo glycation, in hyperglycemic conditions which may increase the susceptibility to oxidation. The aim of this study is to develop a model, based on mass spectrometry (MS) analysis, to identify photooxidative degradation of selected PE (POPE: PE 16:0/18:1, PLPE: PE 16:0/18:2, PAPE: PE 16:0/20:4) and glycated PEs due to UV irradiation. Photooxidation products were analysed by electrospray ionization MS (ESI‐MS) and tandem MS (ESI‐MS/MS) in positive and negative mode. Emphasis is placed in the influence of glycation in the generation of distinct photooxidation products. ESI‐MS spectra of PE after UV photo‐irradiation showed mainly hydroperoxy derivatives, due to oxidation of unsaturated fatty acyl chains. Glycated PE gave rise to several new photooxidation products formed due to oxidative cleavages of the glucose moiety, namely between C1 and C2, C2 and C3, and C5 and C6 of this sugar unit. These new products were identified by ESI‐MS/MS in positive mode showing distinct neutral loss depending on the different structure of the polar head group. These new identified advanced glycated photooxidation products may have a deleterious role in the etiology of diabetic retinopathy and in diabetic retinal microvascular complications. Copyright © 2013 John Wiley & Sons, Ltd.