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排序方式: 共有147条查询结果,搜索用时 281 毫秒
1.
Investigation on chaotic motion in hysteretic non-linear suspension system with multi-frequency excitations 总被引:3,自引:0,他引:3
This paper presents the investigation on possible chaotic motion in a vehicle suspension system with hysteretic non-linearity, which is subjected to the multi-frequency excitation from road surface. The Melnikov’s function is used to derive the critical condition for the chaotic motion, and then it is investigated that the effects of parameters in non-linear damping on the chaotic field. The path from quasi-periodic to chaotic motion is found via Poincaré map and Lyapunov exponents. 相似文献
2.
某些变色酸双偶氮染料-蛋白质体系的共振瑞利散射及其分析应用 总被引:12,自引:0,他引:12
在PH3.4-4.0的缓冲溶液中, 偶氮胂M(AAM)、偶氮氯膦Ⅲ(CPAⅢ)和氯磺酚S(CSPS)等变色酸双偶氮染料及蛋白质本身的共振瑞利散射(RRS)均十分微弱,但这些染料与蛋白质结合形成复合物时能使RRS急剧增强,在400-470nm的范围内呈现高的散射强度,其最大散射波大均位于470nm处,并且散射强度分别在0.36mg/L(CPAⅢ体系)、0-3.8mg/L(AAM体系)和0-4.8mg/L(CSPS体系)的范围内与牛血清白蛋白(BSA)的浓度成正比,方法具有高灵敏度,对于BSA的检出限(σ=3时)分别为18.5μg/L(CPAⅢ)、13.6μg/L(CSPS)和27.9μg/L(AAM)。考察了共存物质的影响,表明方法具有较好的选择性,此法可用于人血清中蛋白质的测定。 相似文献
3.
4.
Li N Luo H Liu S Chen G 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(3):501-507
The interaction of procaine hydrochloride and beta-cyclodextrin in aqueous solution was studied using resonance Rayleigh scattering technology. The molar ratio of the inclusion complex was 1:1 established by spectrophotometry. The resonance Rayleigh scattering technology was first applied in the determination of the beta-cyclodextrin inclusion constant. The inclusion constant of procaine hydrochloride beta-cyclodextrin complex Kf is 1.23 x 10(2) and 1.27 x 10(2) l mol(-1) for method I and 1.15 x 10(2) and 1.21 x 10(2) l mol(-1) for method II. These determination results were in correspondence with the results of the spectrophotometric and fluorescence methods. Therefore, the resonance Rayleigh scattering method can be used as a new technology for the determination of the inclusion constant. 相似文献
5.
甲基绿褪色分光光度法测定维生素K3 总被引:1,自引:0,他引:1
在pH8.7~9.5的弱碱性介质中,维生素K3(VK3)能使甲基绿发生褪色反应,其最大褪色波长为630nm,并在紫外区出现两个新的吸收峰,其褪色程度(ΔA)与VK3浓度在0·11~2·40mg/L的范围呈正比,可用于VK3的分光光度测定。方法具有很高的灵敏度,其表观摩尔吸光系数ε630=2·13×105L·mol-1·cm-1;对VK3的检出限(3σ)为32·0μg/L。方法有较好的选择性,可用于某些药物制剂及血药中VK3含量的测定。 相似文献
6.
When trypsin reacts with Herring sperm DNA (hsDNA), Salmon sperm DNA (sDNA), and Calf thymus DNA (ctDNA) to form a complex,
the resonance Rayleigh scattering (RRS) was remarkably enhanced and new RRS spectra appear. These new spectra have similar
characteristics of RRS spectra. The maximum RRS peaks are at 307 nm (hsDNA, sDNA) and 290 nm (ctDNA), and other peaks are
at 350 nm. The scattering intensity is proportional to the concentration of DNA or trypsin; so this intereaction can be used
to determine trypsin using DNA or DNA using trypsin. In the determination of DNA using trypsin, the linear ranges for hsDNA,
sDNA, and ctDNA are 0–2.3, 0–2.5, and 0–1.9 μg·mL−1, and the detection limits are 0.4, 0.7, and 1.1 ng·mL−1, respectively. In the determination of trypsin using hsDNA, the linear range is 0–30.0 μg·mL−1, and the detection limit is 39.0 ng·mL−1. In this paper, the intereaction conditions were optimized. The affecting factors, chemical properties of the complex, and
the composition ratio of trypsin with DNA were investigated. Using trypsin as RRS probe, a sensitive method for the determination
of trace amounts of DNA was developed.
Translated from Chemical Journal of Chinese Universities, 2006, 27(3) (in Chinese) 相似文献
7.
Qianqian Sun Yuwei Long Hongxi Li Shuang Pan Jidong Yang Shaopu Liu Xiaoli Hu 《Journal of fluorescence》2018,28(2):523-531
Caffeic acid (CA), a familiar color stabilizing reagent, has aroused general concern due to its uncontrolled addition, and thus the detection of CA is increasingly important. In our report, the bright carbon dots (CDs) were prepared via hydrothermal treatment with urea and citric acid act as raw material and their characteristics were discussed through X-ray diffraction (XRD), transmission electron microscopy (TEM) and so on. Impressively, the strong emission of the as-prepared CDs (Quantum Yield: 24.3%) decreased sharply upon a full reaction with the added CA. Hence, we first present an improved strategy for determining CA based upon the quenching of the strong emission of CDs. In this strategy, 0.79–100.0 µmol L??1 caffeic acid could be simply detected, and a detection limit of 0.24 µmol L??1 was allowed. Additionally, CA in red wine samples can be successfully detected by this method and the exploration of the quenching mechanism of the CA-CDs system was done. 相似文献
8.
Liang Wanjun Liu Zhengqing Li Dan Wu Xiaoping Liu Shaopu He Youqiu 《Mikrochimica acta》2015,182(1-2):297-306
Microchimica Acta - We describe a novel fluorescent bioprobe for the sensitive and selective detection of double-stranded DNA (dsDNA). It consists of quantum dots (Q-dots) whose fluorescence is... 相似文献
9.
Nonlinear Dynamics - The primary and subharmonic simultaneous resonance of Duffing oscillator with fractional-order derivative is studied. Firstly, the approximately analytical solution of the... 相似文献
10.
In near neutral medium, the resonance Rayleigh scattering (RRS) intensities of an alone cationic surfactant and nucleic acid are very weak. However, when they combine with each other to form a complex, the RRS intensity of the solution is enhanced greatly. In this paper the reactions of five cationic surfactants with nucleic acids have been studied. The results show that the reaction conditions and RRS spectral characteristics of these reactions are similar, but their sensitivities are obviously different. Among them, the sensitivity of cetyldimethyl benzylammonium chloride (CDBAC) with an aryl and large molecular weight is the highest, while that of cetyl-trimethylammonium bromide (CTAB) without aryl and with small molecular weight is the lowest. The detection limits for ctDNA and yRNA of the former are 6.6 and 29.4 ng · mL-1, while that of the latter are 13.3 and 53.6 ng · mL-1. The method has better selectivity and can be applied to the determination of trace amounts of nucleic acids. Furthermore, i 相似文献