基于递阶质量屋的多属性灰色模糊评价系统研究

质量功能配置中的顾客需求权重以及设计要求权重的获取是产品配置的关键环节.在层次分析法的基础上,应用递阶质量屋方法优化了各因素的权重值,针对出现的模糊语言,利用模糊数对定性指标进行量化,并将灰色系统理论引入设计方案的多属性模糊优选,提出了一种基于递阶质量屋的灰色关联与模糊优选评价方法.该方法综合考虑相关模糊因素交叉耦合后的影响,对方案优劣进行整体比较.实例证明,该方法能够处理复杂的、多层次的、且信息不够完全的问题,评价方法客观准确,可操作性强,能够得到符合客观实际的结果.     

三星型压缩机振动问题研究

提出了引起星型活塞式压缩机振动这一宏观现象发生的根源.在一阶惯性力机器内完全平衡的情形下,对二阶惯性力因目前无法在机器内平衡,分析其形成的机理.在机器向大排量方向发展时,二阶惯性力引起机器振动不可忽略,容易引起机器在水平面内移动,所以需采取与基础紧固的措施.     

用金属卟啉络合物引发合成高分子量聚醚

介绍了用四苯基卟啉铝络合物催化体系合成高分子量聚醚的方法。该聚合过程显示出一种持续特性。产物具有均一的链长和极窄的分子量分布，且数均分子量Ｍｎ可通过改变单体与引发剂的摩尔比来控制。     

无线传感器网络中基于代理的D-S数据融合

提出了一种无线传感器网络中基于移动代理带证据权的D S融合算法。引入证据权对证据进行修正以降低冲突数据对融合结果的影响。采用三级D S组合规则进行融合决策：节点级融合计算单个节点时间域融合检测概率;簇内级融合计算簇内节点间空间域融合检测概率获取局部决策结果;簇间级融合计算簇间的融合检测概率获取最终的全局决策结果。仿真结果表明,本算法能以较小的能耗代价获取准确的融合结果并有效降低冲突数据对融合结果的影响。     

凝胶色谱法表征我国几种有代表性超滤膜的截留率——分子量曲线

本文考察了凝胶色谱法的操作压力和进料流速的影响。对国内具有代表性的几种平板超滤膜(聚砜、聚砜酰胺、醋酸纤维素、聚丙烯腈、聚氯乙烯)以及聚砜中空纤维超滤膜的截留率——分子量曲线进行了测定。并给出它们的切割分子量数据。     

Change in the molecular weight distribution of poly(ethylene oxide) caused by the complexation with poly(acrylic acid)

The complexation between poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) was made by using double the molar quantity of either polymer component at pH 2 where the resulting complex completely precipitates. After the removal of the precipitate, PEO or PAA remaining in the supernatant was subjected to gel permeation chromatography to investigate the change in the molecular weight distribution (MWD) caused by the complexation. No remarkable difference is observed in the MWD curves for PEO[1] (M_w=1.37 × 10⁴) before and after the complexation with PAA[1] (M_w=1.10 × 10³) and PAA[2] (M_w=4.16 × 10⁵). However, the MWD curves of PEO[2] (M_w=1.26 × 10⁵) and PAA[2] become shortened and shift to the low molecular weight side after the complexation with PAA[1] or [2] and PEO[2], respectively. This tendency is enhanced by increasing the complexation temperature. From these results, it is indicated that the complexation between PEO and PAA deals with an equilibrium reaction, and the equilibrium constant is dependent on the chain length of both polymer components and also on the complexation temperature.     

丙烯酰胺水溶液聚合反应的研究

探讨了聚乙二醇作为分散剂时丙烯酰胺水溶液聚合体系中单体含量、还原剂用量对聚合物分子量的影响，并探讨了聚合时间与转化率、单体含量与聚合体系粘度之间的关系。结果表明，在保持聚合体系能够流动的前提下，单体含量可提高到２０％，聚合物的分子量可达３００万以上。     

Gel chromatographic investigation of p-benzoquinone and styrene products copolymerized in the presence of BF3·OEt2

The molecular weight distribution of copolymers of p-benzoquinone and styrene was studied by g.p.c.. It was shown that the products synthesized have low molecular weights and narrow MWD. p-Benzoquinone was found to be a copolymer macromolecule regulator.     

Extrusion of ultrahigh molecular weight polyethylene under ultrasonic vibration field

The effects of polypropylene (PP) and ultrasonic irradiation on the processing and mechanical properties of ultrahigh molecular weight polyethylene (UHMWPE) are studied. The results show that PP can effectively improve the fluidity and mechanical properties of UHMWPE. The Izod notched impact strength increases from 92 kJ/m² for pure UHMWPE to 109.2 kJ/m² for the blend of UHMWPE with 10 wt % PP. The Young's modulus increases from 528 MPa for pure UHMWPE to 1128 MPa when 25 wt % PP is contained in the blend, and the yield strength also rises when PP is added. The application of ultrasonic vibrations during extrusion can prominently decrease the die pressure and apparent viscosity of the melt, thus increasing the output of extrudate. An appropriate ultrasonic intensity and irradiation time can further promote the mechanical properties, while an overdose of irradiation destroys them. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2628–2632, 2003     

Synthesis and properties of new poly(amide imide)s containing trimellitic rings and hydantoin moieties in the main chain under microwave irradiation

Trimellitic anhydride was reacted with 4,4′‐diaminodiphenyl ether in a mixture of acetic acid and pyridine (3 : 2) at room temperature and was refluxed at 90–100°C, and N,N′‐(4,4′‐diphenylether) bistrimellitimide (3) was obtained in a quantitative yield. 3 was converted into N,N′‐(4,4′‐diphenylether) bistrimellitimide diacid chloride (4) by a reaction with thionyl chloride. Then, six new poly(amide imide)s were synthesized under microwave irradiation with a domestic microwave oven through the polycondensation reactions of 4 with six different derivatives of 5,5‐disubstituted hydantoin in the presence of a small amount of a polar organic medium such as o‐cresol. The polycondensation proceeded rapidly and was completed within 7–10 min, producing a series of new poly(amide imide)s in high yields with inherent viscosities of 0.27–0.66 dL/g. The resulting poly(amide imide)s were characterized by elemental analysis, viscosity measurements, differential scanning calorimetry, thermogravimetric analysis, derivative thermogravimetry, solubility testing, and Fourier transform infrared spectroscopy. All the polymers were soluble at room temperature in polar solvents such as N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, and N‐methyl‐2‐pyrrolidone. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3447–3453, 2004