排序方式: 共有127条查询结果,搜索用时 15 毫秒
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区间目标规划与模糊目标规划 总被引:4,自引:0,他引:4
从区间数与模糊数的序关系出发讨论了一类目标函数含区间数系数的非线性规划和目标函数中含有模糊数系数的线性规划问题,提出将相应的规划问题等价地转化为两个依次求解的经典数学规划问题来求最优解. 相似文献
94.
选取遵义(ZY)原煤及其热解半焦,采用常压程序升温还原—质谱法(AP-TPR-MS)与化学法相结合考察了温度和气氛对热解过程中硫变迁行为的影响。结果表明,对于ZY煤而言,黄铁矿和不稳定有机硫除在氮气气氛下500 ℃时热解不能全部分解外,在其他条件下热解时都可以分解。1%氧气对ZY煤中稳定的有机硫的分解有很强的促进作用,不仅可以脱除稳定的有机硫,还可以使更稳定的有机硫断裂生成次稳定的有机硫,在随后的AP-TPR-MS实验过程中,这部分硫在较低的温度下逸出。合成气和1%氧气在700 ℃时与氢气有着相同的脱硫效果。 相似文献
95.
By means of the wet chemical surface modification,the surface of CeO_2 was modified by vinyltrimethoxysilane (VTMS).Infrared spectroscopy was used to investigate the structure of the modified CeO_2 and the result showed that VTMS has been attached onto the surface of CeO_2.Effect of VTMS concentration on the active index of the modified CeO_2 was also studied,and the result indicated that the active index of the modified CeO_2 increases with the increase of VTMS concentration and the optimal concentratio... 相似文献
96.
<正>The effect of ammonium sulfamate(AS) content on the flame retardancy of polyamide 6(PA6) was studied.It is found that the limiting oxygen index(LOI) of PA6 increases with the increase of AS content and the flame retardancy of PA6 is significantly improved.The morphology of the residues after combustion was examined by means of scanning electron microscopy(SEM).SEM results show that AS facilitates the formation of the intumescent char layer with honeycomb-like structure,which inhibits the transfer of heat and mass,and thus improves the flame retardancy of PA6.The thermal degradation of AS flame retarded PA6 was studied by thermogravimetric analysis(TGA).The Kissinger method was applied to estimate the activation energy(E_a) of the degradation.The activation energy of the thermal degradation of PA6 decreases by adding AS,indicating that AS can promote the degradation of PA6. 相似文献
97.
The initial oxidative polymerization kinetics of 2,6-dimethylphenol with a Cu-EDTA complex in water 总被引:1,自引:0,他引:1
The initial oxidative polymerization kinetics of 2,6-dimethylphenol (DMP) catalyzed by a Cu(II)-EDTA complex in water was studied. The initial polymerization rate of DMP (R0) increases with an increase in concentrations of DMP and catalyst. R0 firstly increases with the molar ratio of N/Cu and then decreases. The reaction order with respect to oxygen is 0.1. R0 increases with NaOH concentration and reaches its maximum value at a concentration of 0.50 mol/L. 1/R0 is in direct proportion to 1/[DMP]0, which indicates that the initial polymerization kinetics of DMP in water obeys Michaelis-Menten model. The dissociation rate constant of the intermediate complex (k2) and Michaelis-Menten constant (Km) at various temperatures are calculated. It is found that both k2 and Km increase with an increase in temperature. 相似文献
98.
神华煤直接液化残渣热解特性研究 总被引:6,自引:4,他引:2
通过热重分析技术考察了神华煤直接液化残渣的热解特性。结果表明,和煤热解相比,在相同条件下残渣热解具有更大的失重率和失重速率。残渣热失重分为三个阶段,在173℃以前为残渣热解第一阶段;从173℃~510℃是残渣热解第二阶段,此阶段为残渣的主要失重阶段;510℃以后是残渣热解的第三阶段,在这个阶段残渣继续失重,此阶段的失重是由于残渣的二次分解和残渣中的矿物质分解造成的。通过比较脱油前后残渣热失重曲线发现,残渣主要失重是由于残渣中重质油、沥青烯以及前沥青烯的热解以及挥发造成的。通过脱灰残渣的热解发现,与原残渣相比,脱灰后残渣的失重量变小,矿物质的分解和残渣中有机组分的缩聚是温度高于649℃以后残渣失重的主要原因。由热解特征参数看出,脱油残渣的初始热解温度、最大失重温度以及剧烈热解终温均高于原煤,说明和原煤相比,脱油后残渣中惰性组分不易热解。与原煤和四氢呋喃脱油渣相比,残渣具有最大的失重速率,这是由于残渣中含有大量重质油、沥青烯以及前沥青烯造成的。 相似文献
99.
高温下煤中矿物质对气化反应的影响 总被引:6,自引:2,他引:4
利用XRD对1100℃~1500℃高温下矿物质在弱还原气氛中的变化进行考察,并利用RIR对矿物质进行半定量分析,发现随着温度的升高莫来石含量增大,而SiO2含量下降,符合SiO2-Al2O3二元相图的变化。高温下部分无定形矿物质发生熔融,主要为硅铝酸盐。在煤焦二氧化碳气化过程中,熔融的硅铝酸盐与煤焦表面接触阻碍气化反应进行。利用FT-IR测定了硅铝酸盐结构的变化,说明高温下矿物质对气化反应的影响与硅铝酸盐的聚合程度存在一定的关系。 相似文献
100.
Huan Wang Baoqing Shentu Wenli Zhang Cheng Gu Zhixue Weng 《European Polymer Journal》2012,48(7):1205-1211
Poly(amindoamine) (PAMAM) was grafted onto magnetic Fe3O4 nanoparticles to produce PAMAM grafted Fe3O4 (shortened as Mag-PAMAM). Mag-PAMAM coordinated with Cu(II) to form the supported Cu(II)–PAMAM complex (shortened as Cu(II)/Mag-PAMAM). The stoichiometric ratio between amine groups in Mag-PAMAM and Cu(II) was found to be 4. The Cu(II)/Mag-PAMAM complexes were employed to catalyze the oxidative polymerization of 2,6-dimethylphenol (DMP) in water. The Cu(II)/Mag-PAMAM complexes demonstrated the excellent selectivity of C–O/C–C coupling and reactivity to form poly(2,6-dimethyl-1,4-phenylene oxide) (PPO). After polymerization, the Cu(II)/Mag-PAMAM complexes were recovered by an external magnetic field and used repeatedly in the next run with additional Mag-PAMAM and copper ions. After three runs of oxidative polymerization of DMP, the recovery ratio of the catalyst was about 95% and the yield of PPO maintained a relatively high value. 相似文献