DYNAMICAL ANALYSIS ON A KIND OF SEMI-ACTIVE SUSPENSION WITH TIME DELAY

对一类采用有限相对位移控制的含时滞单自由度半主动悬架系统进行了动力学分析.首先通过平均法得到了该系统的一阶近似解, 然后基于Lyapunov理论建立了系统的稳定性条件, 结果表明近似解的稳态幅值和稳定性条件都是时滞量的周期函数, 并且和外激励具有相同周期.通过对数值解和解析解的幅频曲线进行比较, 验证了一阶近似解析解的准确性, 并且解释了半主动控制中的高频颤振现象.研究了被动悬架系统并且和半主动悬架系统进行了比较, 证实了半主动悬架系统的优越性.最后, 探讨了一些关键的系统参数, 如控制间隙、时滞量、最小阻尼比等对半主动悬架系统稳态幅值的影响.     

The codimension-two bifurcation for the recent proposed SD oscillator

In this paper, the complicated nonlinear dynamics at the equilibria of SD oscillator, which exhibits both smooth and discontinuous dynamics depending on the value of a parameter α, are investigated. It is found that SD oscillator admits codimension-two bifurcation at the trivial equilibrium when α=1. The universal unfolding for the codimension-two bifurcation is also found to be equivalent to the damped SD oscillator with nonlinear viscous damping. Based on this equivalence between the universal unfolding and the damped system, the bifurcation diagram and the corresponding codimension-two bifurcation structures near the trivial equilibrium are obtained and presented for the damped SD oscillator as the perturbation parameters vary.     

DYNAMICAL ANALYSIS ON A KIND OF SEMI-ACTIVE VIBRATION ISOLATION SYSTEMS WITH DAMPING CONTROL 1)

研究了一类基于相对速度反馈的含立方刚度的单自由度非线性半主动隔振系统.通过平均法得到了系统分别在基于加速度-相对速度反馈的加速度驱动阻尼控制策略、速度-相对速度反馈的天棚阻尼控制策略和位移-相对速度反馈的地棚阻尼控制策略下主共振响应的近似解析解,并利用数值解验证了近似解析解的准确性.通过 Lyapunov 理论对不同控制策略下系统的稳定性进行了分析,讨论了系统参数对控制效果的影响.分析结果表明,对 3 种基于相对速度反馈的控制策略进行解析研究时,切换条件中的控制参数具有相同的表达式;在抑制共振响应振幅方面,基于速度-相对速度反馈的天棚阻尼控制策略在低频时的减振效果最好,而基于加速度-相对速度反馈的加速度驱动阻尼控制策略在高频时的减振效果最优;在抑制瞬态响应振幅方面,基于速度-相对速度反馈的天棚阻尼控制策略的减振效果最好.此类解析研究方法可应用到其他半主动开关控制策略中,为半主动隔振系统的控制策略研究提供了有效的方法和手段.     

Ag~+-Cl~--多取代荧光素体系的RRS和RNLS光谱及其分析应用

在pH 3.2~5.7的HAc-Na Ac缓冲溶液中,Ag+与Cl-反应形成Ag Cl.当Ag+适当过量时,Ag Cl与Ag+结合形成[Ag Cl·Ag]+阳离子,它能进一步借静电引力和疏水作用力与曙红B(二溴二硝基荧光素)、曙红Y(四溴荧光素)、乙基曙红(四溴荧光素乙酯)、荧光桃红(四氯四溴荧光素)和虎红(四氯四碘荧光素)等多取代荧光素阴离子(HL-)反应生成离子缔合物[(Ag Cl·Ag)HL].该疏水性离子缔合物可在水相的挤压作用和范德华力的作用下,进一步聚集形成平均粒径约为20 nm的纳米微粒.此时仅引起吸收光谱和荧光光谱的微小变化,但能导致共振瑞利散射(RRS)以及倍频散射(FDS)和二级散射(SOS)等共振非线性散射(RNLS)的显著增强,其中以曙红B体系最灵敏.曙红B体系的最大RRS、FDS和SOS波长分别位于315 nm、350 nm和560 nm处,3种散射增强(ΔIRRS、ΔIFDS和ΔISOS)在一定范围内均与氯离子浓度成正比,均可用于氯离子的测定.其中以FDS法最灵敏,RRS法次之.3种方法(RRS、FDS和SOS法)对于氯离子的检测,曙红B体系的线性范围分别是0.005~1.22μg/m L、0.004~2.92μg/m L和0.01~1.94μg/m L,检出限分别为1.50 ng/m L、1.20 ng/m L和3.90 ng/m L.本文研究了[(Ag Cl·Ag)HL]n纳米微粒的形成、散射强度的提高、适宜的反应条件及影响因素,考察了共存物质的影响,表明方法具有良好的选择性.据此利用上述反应,发展一种RRS、SOS和FDS技术高灵敏、高选择性和简便、快速测定环境空气和废气中HCl及环境水样中氯化物的新方法.文中还对反应机理和散射增强的原因进行了讨论.     

Resonance Rayleigh scattering spectra for studying the interaction of anthracycline antineoplastic antibiotics with some anionic surfactants and their analytical applications

In pH 5.8 acidic medium, the anionic surfactants such as sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS) or sodium dodecyl sulfonate (SLS) can react with anthracycline antibiotics such as epirubicin (EPI), daunorubicin (DNR) or mitoxantrone (MXT) to form ion-association complexes, which lead to a great enhancement of resonance Rayleigh scattering (RRS) intensity and appearances of new RRS spectra. The maximum RRS peaks are situated at 313 nm for SDS-DNR and SDS-EPI system, 296 nm for SDS-MXT system. The linear ranges and detection limits for EPI, DNR and MXT are 0.26-20.0, 0.25-20.0, 0.14-10.0 and 0.074, 0.078, 0.042 μg mL⁻¹, respectively. In this paper, the characteristics of the absorption, fluorescence and RRS spectra of the reaction products are studied as well as the optimum reaction conditions and analytical chemistry properties. A sensitive, simple and rapid RRS method for the determination of anthracycline anticancer antibiotics has been developed.     

秋水仙碱水解产物与某些酸性磺酞类染料相互作用的 共振瑞利散射光谱及其分析应用

在pH 2.9～4.6 Britton-Robinson (BR)缓冲溶液中, 秋水仙碱的水解产物(H-COL)能与溴酚蓝(BPB)、溴甲酚绿(BCG)、溴百里酚蓝(BTB)和百里酚蓝(TB)等酸性磺酞类染料(ASPD)反应形成1∶1的离子缔合物, 此时将引起共振瑞利散射(RRS)的急剧增强, 并产生新的RRS光谱. 秋水仙碱水解产物与溴酚蓝、溴甲酚绿、溴百里酚蓝和百里酚蓝形成离子缔合物的最大散射波长分别位于327, 311, 305和306 nm处. 散射增强(ΔI)与秋水仙碱浓度在一定范围内成正比, 不同体系对于秋水仙碱的检出限(3σ)分别为12.3, 15.1, 16.4和20.0 ng•mL－1 (TB). 研究了适宜的反应条件, 考察了共存物质的影响, 表明方法有较好的选择性. 基于秋水仙碱水解产物与酸性磺酞类染料离子缔合物的反应, 发展了一种较灵敏, 且简便、快捷测定秋水仙碱的新方法. 方法用于片剂、黄花、血清和尿样中秋水仙碱的测定, 获得了满意的结果.     

共振瑞利散射法测定盐渍食品中的亚铁氰化钾

1引言研究发现,在弱酸性介质中,当Fe(Ⅲ)与亚铁氰化钾反应生成普鲁士蓝时,在引起吸收光谱变化的同时,将导致共振瑞利散射(RRS)的显著增强,其最大散射波长在316nm,它不仅是灵敏度高,检出限达4.36μg/L,远远高于分光光度法(检出限为1mg/L),而且有色盐渍食品本身的颜色不产生共振瑞利散射,因此不干扰测定。从而解决了盐渍食品本身颜色对分光光度法测定亚铁氰化钾的困扰。据此提出了一种灵敏度高、选择性好、而且简便快速的RRS法。2实验部分2.1仪器与试剂F-2500型荧光分光光度计(日本岛津公司),狭缝宽度10nm;UV-8500型紫外-可见分光光度计(…     

Determination of Tetracaine Hydrochloride by Fluorescence Quenching Method with Some Aromatic Amino Acids as Probes

A novel fluorescence quenching method for the determination of tetracaine hydrochloride (TA·HCl) concentration with some aromatic amino acids as fluorescence probe has been developed. In pH 6.3 acidic medium, tryptophane (Trp), tyrosine (Tyr) or phenylalanine (Phe) can react with tetracaine hydrochloride to form an ion-association complex by electrostatic attraction, aromatic stacking interaction and Van der Waals’ force, which lead to fluorescence quenching of above amino acids. The maximum fluorescence excitation and emission wavelengths of them are located at 278, 274, 258 nm and 354, 306, 285 nm, respectively. The relative fluorescence intensity (F ₀/F) is proportional to the TA·HCl concentration in certain range. The linear ranges and detection limits are 1.2–5.0 μg/mL and 0.37 μg/mL for Tyr-TA·HCl system, 1.3–6.0 μg/mL and 0.38 μg/mL for Trp-TA·HCl system, and 1.4–6.0 μg/mL and 0.41 μg/mL for Phe-TA·HCl system. The optimum reaction conditions, influencing factors and the effect of coexisting substances are investigated. And the results show the method has a good selectivity. Judging from the effect of temperature, the Stern-Volmer plots and fluorescence lifetime determination, the quenching of fluorescence of amino acids by TA·HCl is a static quenching process.     

The dynamics of a novel method coupling high-performance liquid chromatography with resonance Rayleigh scattering

The dynamics of a novel method coupling high‐performance liquid chromatography (HPLC) with resonance Rayleigh scattering (RRS) is presented in the paper. The method was employed in the detection of fluoroquinolones (FQs) of urine samples from healthy human beings, by forming ion‐association complexes between the components separated from HPLC and [Ce(OH)₃]⁺ as the molecular recognition probe. The RRS signal was measured at λ_ex=λ_em=365 nm. It was applied to detect three FQs and obtained satisfactory results. The RRS spectral characteristics of the analytes and the kinetics of flow rate, proportion of organic phase, reaction time and the aggregation level of ion‐association complexes were investigated, which provided a new basis for the development of the hyphenated techniques. It was established that the presence of HPLC‐RRS would open up a new field in the determination of analytes in the absence of UV or fluorescence.     

2-(2-噻吩偶氮)-5-二乙氨基酚反相液相色谱法分离测定铜(Ⅱ)、钴(Ⅱ)、镍(Ⅱ)

本文以2-(2-噻吩偶氮)-5-二乙氨基酚(简称TADAP)作柱前显色剂,反相色谱法分离测定铜(Ⅱ)、钴(Ⅱ)、镍(Ⅱ)离子。用含有1.5×10~(-4)mol/L的TADAP,0.1mol/L氯化锂和0.1mol/L乙酸盐(pH4)的甲醇(60％)-水(40％)溶液作为流动相,流量为0.9ml/min,紫外-可见检测器检测波长为545nm。在此条件下,铜(Ⅱ)、钴(Ⅱ)、镍(Ⅱ)螯合物得到最佳分离,并定量测定了茶叶中铜、钴、镍的含量,与原子吸收分光光度法测定,得到一致的结果。