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41.
Electrostatic spring softening is an important characteristic of electrostatically actuated dual-axis micromirror, since it lowers the resonant frequencies. This paper presents an approach based on approximating the electrostatic forces by the first-order Taylor's series expansion to investigate this characteristic. The dual-axis micromirror studied in this paper has three motion modes, two torsional (about x- and y-axis, respectively) and one translational (about z-axis). The stiffnesses of all these modes are softened by a DC bias voltage applied to the mirror plate. The resonant frequencies are lowered with the increment of the bias voltage. The relationship of the bias voltage and the resonant frequencies of all the motion modes is derived. The analytical results show that the resonant frequency curves are affected by the capacitor geometries, i.e. the gap between the mirror plate and the electrodes and the electrodes size. The lowering curves drop slowly when the bias voltage is small. While for large bias voltage, the lowering curves drop rapidly. The experiment results are consistent with those obtained by the analytical approach. 相似文献
42.
T. V. Ramakrishnan H. R. Krishnamurthy S. R. Hassan G. Venketeswara Pai 《Journal of Chemical Sciences》2003,115(5-6):767-774
Manganites of the LA1−x
Ca
x
MnO3 family show a variety of new and poorly understood electronic, magnetic and structural effects. Here we outline a new approach
recently proposed by us, where we argue that due to strong Jahn-Teller (JT) coupling with phonons the twofold degeneratee
g
states at the Mn sites dynamically reorganize themselves into localised, JT polaronsl with exponentially small inter-site hopping, and band-like, nonpolaronic statesb, leading to anew 2-band model for manganites which includes strong Coulomb and Hund’s couplings. We also discuss some results from a dynamical mean-field theory treatment
of the model which explains quantitatively a wide variety of experimental results, including insulator-metal transitions and
CMR, in terms of the influence of physical conditions on the relative energies and occupation of thel andb states. We argue that this microscopic coexistence of the two types of electronic states, and their relative occupation and
spatial correlation is the key to manganite physics.
Dedicated to Professor C N R Rao on his 70th birthday 相似文献
43.
Gui-Jun Yang 《应用数学学报(英文版)》2007,23(1):107-112
It is useful to know the maximum number of clear two-factor interactions in a_Ⅲ~(m-(m-k))design.This paper provides a method to construct a 2_Ⅲ~(m-(m-k))design with the maximum number of clear two-factorinteractions.And it is proved that the resulting designs have more clear two-factor interactions than thoseconstructed by Tang et al.Moreover,the designs constructed are shown to have concise grid representations. 相似文献
44.
LiZHANG NaLI FengLinZHAO KeAnLI 《中国化学快报》2004,15(6):671-674
The interaction between heparin and neutral red was investigated by molecular spectroscopic methods. The change of all spectra suggested that positively charged neutral red had interacted with negatively charged heparin. The study of influence factors indicated that electrostatic force and hydrophobic bond might be involved in the interaction. The total binding number per disaccharide unit and intrinsic binding constant were obtained using Scatchard model. 相似文献
45.
Jerman S Podgornik A Cankar K Cadet N Skrt M Zel J Raspor P 《Journal of chromatography. A》2005,1065(1):107-113
The availability of sufficient quantities of DNA of adequate quality is crucial in polymerase chain reaction (PCR)-based methods for genetically modified food detection. In this work, the suitability of anion-exchange CIM (Convective Interaction Media; BIA Separations, Ljubljana, Slovenia) monolithic columns for isolation of DNA from food was studied. Maize and its derivates corn meal and thermally pretreated corn meal were chosen as model food. Two commercially available CIM disk columns were tested: DEAE (diethylaminoethyl) and QA (quaternary amine). Preliminary separations were performed with standard solution of salmon DNA at different pH values and different NaCl concentrations in mobile phase. DEAE groups and pH 8 were chosen for further isolations of DNA from a complex matrix-food extract. The quality and quantity of isolated DNA were tested on agarose gel electrophoresis, with UV-scanning spectrophotometry, and by amplification with real-time PCR. DNA isolated in this way was of suitable quality for further PCR analyses. The described method is also applicable for DNA isolation from processed foods with decreased DNA content. Furthermore, it is more effective and less time-consuming in comparison with the existing proposed methods for isolation of DNA from plant-derived foods. 相似文献
46.
47.
聚电解质与相反电荷表面活性剂的相互作用 总被引:2,自引:0,他引:2
通过透光度测定、电导滴定和粘度法考察了阳离子聚电解质聚苯乙烯 4 乙烯基吡啶硫酸甲酯盐与阴离子表面活性剂十二烷基硫酸钠 (SDS)的相互作用。研究表明 ,在表面活性剂未过量时 ,二者之间的静电作用占主导地位 ,并且当二者电荷总量相等时 ,生成的复合物沉淀最多 ;在表面活性剂过量后 ,复合物可部分溶解 ,溶解的原因是疏水相互作用。本文初步阐述了二者的作用机理 相似文献
48.
Dominique Dehareng Georges Dive Josette Lamotte-Brasseur Jean-Marie Ghuysen 《Theoretical chemistry accounts》1989,76(2):85-94
Summary The electrostatic interaction energy between methanol and the dyad water-imidazole has been computed numerically at three levels of approximation from 3D grids of the charge density of one partner and the electrostatic potential of the other. The minimum positions and energy values thus obtained compare well with those calculated analytically. The numerical procedure is especially interesting for the prediction of the stable conformers. 相似文献
49.
Apparent molal heat capacities
of some piperidine, morpholine, and piperazine derivatives in aqueous solution have been determined by adiabatic calorimetry
in the temperature range 20–55°C and in the molality range 0.2–1m. Comparison of experimental
values with those calculated through group contributions, found for monofunctional compounds, indicates strong interactions
between the hydrophilic centers. An interpretation is given of the possible mechanism of this interaction. Also, values of
ΔC
p
for the addition reaction of proton to nitrogen centers of mono- and bifunctional organic compounds are examined. 相似文献
50.
R. Winkler J. Wilhelm M. Capitelli C. Gorse 《Plasma Chemistry and Plasma Processing》1992,12(1):71-87
Calculations of the electron energy distribution and of relevant macroscopic quantities of collision-dominated, weakly ionized plasmas under rf field action have been performed with increasing degrees of ionization, and the impact of the electron-electron interaction on these quantities was determined. The investigations were performed for the gas plasmas in CO and H2 as representatives of molecular plasmas The energy distribution and macroscopic quantities are obtained by solving the nonstationary Bolizmann equation for a given rf field and degree of ionization taking into accoung and additional Fokker-Planck term besides the collision integrals for the elastic and the main inelastic collision processes. In these molecular plasmas a remarkable impact of the electron-electron interaction connected with increasing Maxwellization is observed for degrees of ionization greater than 10. 相似文献