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91.
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Hai‐Xia Yang Yan‐Feng Li Jin‐Gang Liu Shi‐Yong Yang Da‐Xue Yin Lincheng Zhou Lin Fan 《应用聚合物科学杂志》2004,91(6):3981-3990
A series of new polymerized monomer reactants (PMR) matrix resins of poly(pyrrolone‐benzimidazole)s containing a pyridine unit (PPBP) were synthesized by polycondensation of monoethyl ester of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic acid, 2,6‐diphenyl ester pyridinedicarboxylic acid or 3,5‐diphenyl ester pyridinedicarboxylic acid, and diethyl ester of 4,4′‐oxydiphthalic acid with 3,3′‐diaminobenzidine in a mixing solution of anhydrous ethyl alcohol and N‐methylpyrrolidone under given temperature and pressure conditions. The resulting resin solutions showed good solubility in polar organic solvents and stability at room temperature. The corresponding PPBP matrix resin, molded powder, and molded plate were prepared by undergoing amidation, imidization, cyclization, and crosslinking reactions when the reaction temperature was increased from 80 to 350°C, successively; the crosslinking structure was formed by the reverse Diels–Alder reaction at 270–290°C under 50 MPa pressure (2.5–3.5 MPa displayed by the pressure meter). The chemical reactions and properties of the resulting PPBP were studied by means of FTIR, TGA, and DMA methods, and the results indicated that the kinds of PPBP materials retain excellent thermal stability and processability; when the initial decomposition temperature was above 620°C the Tg was at 413.5°C for 3,5‐PPBP‐20 molded plate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3981–3990, 2004 相似文献
94.
青花红绿彩作为加彩器的一种,比传统的观点早一个朝代,根据明中青花红绿彩盖罐结合最新的窑址考古成果,得出元代的窑炉设计和釉面配方的缺陷,使元代青花红绿彩的生产和存世极少,明官窑中由于斗彩的出现,青花红绿彩在民间一直沿烧。与元代风格相近,只是到了后期风格才大变。 相似文献
95.
96.
This paper considers the problem of employing multiple unmanned aerial vehicles (UAVs) to the mobile ad hoc network (MANET) as relay backbone nodes to construct the backbone network, to improve the network connectivity, and to address many issues in the MANET such as linkage, capacity, load balance, and reliability. With considering the dynamic nature of the problem, this study provides several linear location problem models and their extensions to accommodate these issues. Due to the size of linear location models associated with a large number of constraints, the problem becomes computational challenging even with modest size of nodes. To overcome the computational barrier, we recast these location problem models using a quadratic unconstrained binary optimization (QUBO) framework and solve these QUBO models with a Tabu search heuristic with preprocessing. The analysis of the solutions that are produced by QUBO together with the comparisons made with the linear model highlight both the attractiveness and robustness of the proposed approach. The results of this study provide support to future advanced routing protocol development. 相似文献
97.
Two-dimensional locality preserving projections (2DLPP) was recently proposed to extract features directly from image matrices based on locality preserving criterion. A significant drawback of 2DLPP is that it only works on one direction (left or right) to reduce the dimensionality of the image matrices and thus too many coefficients are needed for image representation in low-dimensional subspace. In this paper, we propose a novel method called two-dimensional bilinear preserving projections (2DBPP) for image feature extraction. We generalized the image-based (2D-based) feature extraction techniques into bilinear cases, in which 2DLPP is a special case of our proposed method. In order to obtain the bilinear projections, we proposed an iteration method by solving the corresponding generalized eigen-equations. Moreover, analyses show that 2DBPP has stronger locality preserving abilities than 2DLPP. By using the label information and defining different local neighborhood graphs, the proposed framework is further extended to supervised case. Experiments on three databases show that 2DBPP and its supervised extension are superior to some other image-based state-of-the-art techniques. 相似文献
98.
以丙烯酸-丙烯酰胺为单体,过硫酸钾为引发剂,N,N-亚甲基双丙烯酰胺为交联剂。水浴阶梯升温共聚合成耐盐性树脂,采用正交试验通过分析,研究了主要因素对产物性能的影响,确定较佳反应条件:T=50℃(2h)~65℃(3h),单体配比nAM:nAA=1:11,单体中和度[N]=90%~95%。引发剂浓度[I]=0.3%,单体浓度[M]=30%~35%,交联剂浓度[C]=0.025%~0.03%,并将此树脂作为缓释剂应用于固载二氧化氯中,取得了良好的效果。 相似文献
99.
在时间序列分段线性表示(PLR)基础上,提出用相对点平均误差度量子序列过程状态变化程度,改进过程数据PLR模型分段算法,克服采用单一误差算法的模型失配问题,更加准确地反应过程状态的变化。 相似文献
100.
The adsorption of dyes from aqueous solution using diatomite 总被引:2,自引:0,他引:2
Raw diatomite was calcined at 450 °C for dyes removal from aqueous solution. SEM and FTIR analysis show that the raw diatomite
contains organic impurities, which are removed after the calcination. The impurities removal decreases the specific surface
area and increases the average pore diameter of raw diatomite, while improves its adsorption capability of dyes. The adsorption
isotherm and kinetics experiments of methylene blue onto calcined diatomite were then carried out to investigate the adsorption
property. It shows that the adsorption capacity of methylene blue is about 50 mg/g. The adsorption isotherm was fitted by
the Langmuir, Freundlich and Redlich-Peterson models, which reveals that the Redlich-Peterson isotherm is the best one. Two
kinetic models, pseudo-first order and pseudo-second order, were rearranged for expediently investigating the adsortpion mechanisms.
Fitting results show that the pseudo-first-order model is better in describing the adsorption process. 相似文献