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161.
针对具有时变时滞的中立型Hopfield神经网络,在对时变时滞的合理假设下,文中通过构造适当的Lyapunov泛函,提出了一种新的方法判定时变时滞中立型Hopfield神经网络系统的全局一致渐近稳定性。所得判据是建立在一个代数Riccati方程及其对应离散Lyapunov方程存在对称正定解之上的,并得出了易于计算机仿真实现的线性矩阵不等式的判据形式,仿真验证了结果的有效性。 相似文献
162.
《青岛科技大学学报(自然科学版)》2010,(5)
以偶氮氯膦Ⅲ(CPAⅢ)作为显色剂,研究可见光分光光度计测定含偕胺肟基功能高分子膜螯合电极对铀酰离子的吸附量的实验方法。确定了分光光度法测定的铀酰离子吸附量的实验条件:吸收光波长670 nm,CPAⅢ标准溶液(0.001 mol.L-1)的用量3mL,测定体系的最佳pH值1.0,室温下显色时间2 min。在此实验条件下,绘制了铀的工作曲线,并得到摩尔吸光系数为ε=29 750 mol-1.L.cm-1。对比电子能谱法所测定的脱附铀前后的螯合电极表面的铀含量(脱附前后亮区铀含量分别为38.12%和6.29%,暗区铀含量都为零),得到分光光度计法测定的铀含量并不是螯合电板表面的真实铀含量,但却是脱附下来的铀的真实量,这肯定了分光光度法测定铀的吸附量优势所在。 相似文献
163.
164.
Composite particles composed of solid powders and polymer were prepared by semichemical recycle of wasted plastics. Waste expanded polystyrene was used as raw materials of polymer matrix of composite particles. Both magnetite and silicon carbide powders were used as solid powders to give thermal and electric conductivity and magnetization, respectively. In the experiment, the oil‐phase dissolving expanded polystyrene was dispersed in fine droplets into the continuous water phase. Two kinds of powders were added at the same time or separately in the O/W dispersion. Composite particles were found to have the structure that polymer particle was covered with two kinds of solid powders. The mean diameter of composite particles and the content of each solid powder were strongly affected by the addition time when silicon carbide powder was added into the dispersion. Furthermore, it was found that the gradient adhesion layer due to two solid powders was able to be formed on the surface of polymer particle. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 483–488, 2003 相似文献
165.
Commercial activated carbon (AC) was used as a support either in its original form or after various modifications, giving
diverse textural and surface chemical characteristics. The changes of these properties were monitored by N2 adsorption–desorption isotherms, temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). Ag catalysts
were prepared over the AC supports by a conventional wet impregnation method. The catalytic performances of supported Ag/AC
catalysts in the selective oxidation of CO in excess H2 were tested. The results indicate the textural and surface chemical characteristics are responsible for the different catalytic
performances. 相似文献
166.
R. Pandiselvam M.R. Manikantan V. Divya C. Ashokkumar R. Kaavya Anjineyulu Kothakota 《臭氧:科学与工程》2019,41(6):491-507
ABSTRACTOzone processing is one of the encouraging non-thermal and bio-friendly techniques in the food processing sector. The applicability of ozone technology in food industry is increasing due to its antimicrobial action and modification of functional properties of the foods. The structural modifications of starches have major applications in the food and bakery industry for producing products with increased shelf life, improved texture, and retention of moisture content. The positive response of ozonation in carboxyl and carbonyl group alters the viscosity of starch molecules. Rheological characteristics like low viscosity even at an increased concentration, desirable binding properties, and film-forming ability have increased its use in the food processing industry. The influence of ozonation in the physicochemical properties is mainly retrogradation and cross-linking of amylose and amylopectin molecules and enzymatic modifications. Ozonation cause change in crystallinity, viscosity, expansion ratio, and gelatinization temperatures. Finally, ozonation induces many possible changes in native starches for the effective utilization in the processing sectors. In this review, starch modifications utilizing ozone and various research achievements and scientific reports focusing on the effect of ozonation in terms of physical, chemical, and thermal properties of native starches and on the possible modifications have been summarized and discussed. In conclusion, ozone is a green technology that can be effectively used as an alternative oxidation technique for starch modification. 相似文献
167.
Uniform polystyrene (PSt) particles with the size of 1.9 μm were first prepared via dispersion polymerization, and then used as the seeds in a second‐stage dispersion copolymerization of styrene (St) and methacrylic acid (MAA) to produce carboxyl‐carrying microspheres. The PSt seed particles were swollen by monomer mixture of St and MAA, including an oil‐soluble initiator 2,2′‐azobisiso‐butyronitrile (AIBN), before polymerization. Finally, uniform PS/P(St/MAA) (polydispersity index, PDI = 1.02) microspheres with the size of 2.2 μm were obtained. The average particle size and size distribution of the final microspheres were investigated. MAA contents between 54 and 97 mg/g were detected from the PS/P(St/MAA) particles produced under different conditions. Dispersion medium has great influence on the kinetics of polymerization, due to its effect on the partitioning of monomers, solvents, and initiator in the particle phase, probably as well as on the conformation of the dispersion agent on the surface of the particles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3586–3591, 2006 相似文献
168.
169.
徐志庭 《广东工业大学学报》1991,(4)
本文研究下列二阶泛函微分方程解的振动性质: (r(t)x′(t))′+q(t)x′(t)+M(t,x(g(t)))=0给出了方程(*)存在非振动解的必要条件以及存在振动解的充分判据。 相似文献
170.
In this article, we study the delay‐dependent stability of a class of hybrid neutral stochastic differential equations (NSDEs) with multiple delays which is highly nonlinear. Some novel stability criteria are investigated according to Lyapunov functions and generalized Itô's formula. In particular, we generalize and improve the results in Shen et al, Systems & Control Letters (2018) from a single delay to multiple delays. 相似文献