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61.
Ravi P. Agarwal Tongxing Li Chenghui Zhang 《Journal of Difference Equations and Applications》2013,19(10):1563-1579
The objective of this note is to present new Hille and Nehari type asymptotic criteria for a class of third-order delay dynamic equations on a time scale. Assumptions in our theorems are less restrictive, whereas the proofs are significantly simpler compared to those reported in the literature. The results obtained extend and improve some previous results. 相似文献
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Jiao?Yan Yafei?Huang Chenghui?ZhangEmail author Zongzhuang?Fang Wenhui?Bai Mengmeng?Yan Chao?Zhu Ailiang?ChenEmail author 《Mikrochimica acta》2017,184(1):59-63
It is known that gold nanoparticles (AuNPs) possess peroxidase-like activity. They can catalyze the oxidation of 3,3,5,5-tetramethylbenzidine by H2O2 which leads to a color change from red to blue. It is shown here that the peroxidase-like activity of AuNPs can be inhibited by passivating its surface passivation with a ssDNA aptamer against sulfadimethoxine. If, however, the target molecule (sulfadimethoxine) is present, the aptamer is desorbed from the AuNPs surface, and this results in the reactivation of the catalytic property of the AuNPs. The color change of the solution (from purple to blue) is related to the analyte concentration, and this can be judged visually or by UV-visible absorptiometry at 650 nm. The assay, under optimized conditions, has a detection limit of 10 ng·mL?1 of sulfadimethoxine, and the calibration plot is linear over a rather wide concentration range (0.01–1000 μg·mL?1). The assay can be performed within <15 min, is sensitive, and therefore is well suited for fast screening in food analysis. Conceivably, it can be extended to many other small analytes for which aptamers are available. 相似文献
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Chenghui Zhang Mehmet Tamer Şenel Tongxing Li 《Journal of Applied Mathematics and Computing》2014,44(1-2):511-518
We study oscillatory properties of a class of second-order neutral differential equations. New results essentially simplify the examination of the equations studied. In particular, these results extend those reported in the paper by Baculíková and D?urina (Comput. Math. Appl. 61:94–99, 2011). 相似文献
67.
Ravi P. Agarwal Martin Bohner Tongxing Li Chenghui Zhang 《Mediterranean Journal of Mathematics》2014,11(4):1115-1127
We study oscillation of certain second-order neutral dynamic equations under the assumptions that allow applications to dynamic equations with both delayed and advanced arguments. Some new comparison criteria are presented that can be used in cases where known theorems fail to apply. 相似文献
68.
本文研究了纯铝粉和快速凝固铝-锂合金粉的爆炸烧结工艺,测量了烧结体的密度,观察了烧结体内的微观组织和断口形貌。试验用粉末材料为水雾化铝粉、氮气雾化铝粉和氩气雾化铝-锂合金粉。试验时把粉末材料装在包套内,粉状炸药装在包套外的纸筒内,炸药从一端起爆。根据文中给出的爆炸烧结工艺参数的设计原则,通过系统地试验,已获得Φ17×70 mm的铝-锂棒材和Φ100×100 mm的纯铝棒材,相对密度超过98%,无中心孔(马赫孔)。微观组织和断口形貌观察结果表明:颗粒之间已达到焊接结合,结合区是由超细微晶组成,颗粒内部仍保持原始粉末的急冷组织。试验结果还表明:包套最终运动速度、包套内径、粉末材料强度、粉末材料表面氧化膜的厚度都是影响爆炸烧结质量的重要因素。 相似文献
69.
Yunan Cui Chenghui Meng Ryszard Płuciennik 《Southeast Asian Bulletin of Mathematics》2000,24(2):201-210
A new constant C(X) for any Banach space X is introduced. It is proved that C(X) < 2 implies the weak Banach—Saks property for the space X. In particular, C(cesp) is found for Cesàro sequence space cesp (1 < p < ). Moreover, it is shown that the space cesp (1 < p < ) has property ().AMS Subject Classification (2000), 46E30, 46E40, 46B20Supported by NSF and ECF of China. 相似文献
70.
Shuping Ma Chenghui Zhang Zhaolin Cheng 《Journal of Computational and Applied Mathematics》2008,217(1):194-211
The robust memoryless state feedback H∞ control problem for uncertain time-delay discrete-time singular systems is discussed. Under a series of equivalent transformation, the equivalence of this problem and the robust state feedback H∞ control problem for standard state-space uncertain time-delay discrete-time systems is presented. In terms of matrix inequality, the delay-dependent sufficient condition for the solution of this problem is given, the design method of the memoryless state feedback controller and the controller are also given. 相似文献