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881.
FENG Hui ZHANG Xue-na WANG Ze-xin DIAO Zhao-yu QIAN Zhao-sheng 《高等学校化学研究》2007,23(2):226-232
IntroductionThe interaction of oxygen with iron in lowcoverageregimes is considered to be an important step in the for-mation of oxides in corrosion science and in Fisher-Tro-psch process for the synthesis of ammonia over the het-erogeneous catalysts[1]. … 相似文献
882.
DIAO Zhao-yu ZHANG Xue-na WANG Ze-xin ZHANG Jing 《高等学校化学研究》2007,23(4):456-459
The O-Ag(210)surface adsorption system was studied via the five-parameter Morse potential theory.Meanwhile,the 2O-Ag(210)system was investigated via the extended London-Eyring-Polanyi-Sato(LEPS)potential theory to learn the interaction between the adsorption states.Calculated results demonstrate that there are two stable on-surface adsorption sites(B and H)for O atoms on Ag(210)stepped surface.And the perpendicular vibrations are 30.3 and 42.9 meV,which are close to that observed in high resolution electron energy loss spectroscopy(HREELS).Also,there exists an octahedral subsurface adsorption state with a high vibrational frequency,and the interaction between the on-surface and subsurface O species is slight.The mode at 54.6 meV,which is close to that observed in HREELS(54-56 meV),is because of the vibration of the O atom on B site under the influence of that on H site. 相似文献
883.
We analyze anti-plane vibrations of a circular cylindrical elastic shell electrically driven by a piezoelectric actuator.
The equations of linear elasticity and linear piezoelectricity are used. The mathematical problem is solved using trigonometric
series. Basic vibration characteristics including resonant frequencies, mode shapes and electric admittance are calculated. 相似文献
884.
An investigation of the vibration damping capability of granular treatments is presented. Cavities in aluminum and sandwich
beams were filled with the lightweight particles made of polyimide. For analysis of vibration damping, the complex stiffness
of structures before and after damping treatment was measured. Particles of different sizes, weights and polymer composition
were used in the damping treatments. Large, frequency-dependent variations in structural loss factor depending on the types
of particles were observed. This behavior was predicted by the Rayleigh-Ritz method. The frame wave propagation characteristics
of the particles were measured and used in the numerical simulation. The acoustic–structure interaction between particles
and structures enhances the dissipation of vibration energy. 相似文献
885.
A mathematical model is developed to describe oscillatory and progressive motions in dynamics of a plastic impact oscillator with a frictional slider. Dynamics of the impact oscillator is analyzed by a five-dimensional map, which describes free flight and sticking solutions of two masses of the system, between impacts, supplemented by transition conditions at the instants of impacts. Piecewise property and singularity are found to exist in the Poincaré map. The piecewise property is caused by the transitions of free flight and sticking motions of impacting masses immediately after the impact, and the singularity of the map is generated via the grazing contact of impacting masses immediately before the impact. These properties of the map have been shown to exhibit particular types of sliding and grazing bifurcations of periodic-impact motions under parameter variation. The influence of piecewise property, grazing singularities and various parameters on dynamics of the vibro-impact system is analyzed. The global bifurcation diagrams for before-impact velocity versus forcing frequency are plotted to predict much of the qualitative behavior of the system. The global bifurcations of period-n single-impact motions of the plastic-impact oscillator are found to exhibit extensive and systematic characteristics. 相似文献
886.
The effect of thermal gradient on the free vibration of clamped visco-elastic rectangular plate with linearly thickness variations
in both the directions has been studied here. The governing differential equation has been solved using Rayleigh-Ritz technique.
The frequency equation is derived for the clamped boundary condition on all the four edges. The effect of linear temperature
variation has been considered. Deflection and time period corresponding to the first two modes of vibrations of a clamped
plate have been computed for various values of aspect ratio, thermal constants, and taper constants. 相似文献
887.
The theoretical solutions of eigenfrequencies and vibration modes of a rectangular thin plate on an elastic foundation with completely free boundary are derived by using a double finite cosine integral transform method. In the analysis procedure, the elastic foundation is regarded as a Winkler elastic foundation model. Because the basic dynamic elasticity equations of the thin plate on elastic foundation are only used, it is not needed to select the deformation function arbitrarily. Therefore, the solution developed in the present paper is more reasonable and more accurate. To prove the correctness of the solutions, numerical results obtained using the present solutions are compared with those in the literatures. 相似文献
888.
M. A. Raggi F. Bugamelli C. Sabbioni D. De Ronchi S. Pinzauti V. Volterra 《Chromatographia》2000,51(3-4):147-153
Summary An HPLC method with electrochemical detection has been developed for the determination of clozapine and its main metabolites,
desmethylclozapine and clozapine N-oxide, in human plasma. An accurate pretreatment of the biological samples was implemented
by means of solid phase extraction (SPE) on HLB cartridges. This improved pretreatment, together with a new mobile phase,
allows for the accurate determination of clozapine N-oxide, which could not be quantitated by a previous method. The method
uses only 100 μL of plasma for one complete analysis and shows good recovery values for all three analytes. The eluates from
the SPE procedure were chromatographed in a reversed phase C18 column using a mobile phase composed of phosphate buffer, acetonitrile
and methanol. Clozapine, desmethylclozapine and clozapine N-oxide were eluted in less than 10 minutes, without any interference
from the biological matrix. Linearity was observed over the 2.50–150 ng mL−1 (clozapine and desmethylclozapine) or 1.25–75 ng mL−1 clozapine N-oxide) range for the three analytes, with satisfactory repeatability values. The limit of detection was 0.3 ng
mL−1 for clozapine and desmethylclozapine, samples of patients treated with Leponex gave good results. No interference from other
common central nervous system drugs was found. This method seems to be a useful tool for pharmacokinetic studies and for clinical
monitoring, because of its need for small plasma samples and its high sensitivity and selectivity. 相似文献
889.
B Mukherjee S Muralithar R P Singh R Kumar K Rani S C Pancholi R K Bhowmik 《Pramana》2000,55(3):L471-L478
Excited states of 63Cu were populated via the 52Cr+10O (65 MeV) reaction using the gamma detector array equipped with charged particle detector array for reaction channel separation.
On the basis of γ-γ coincidence relations and angular distribution ratios, a level scheme was constructed up to E
n=7 MeV and J
π=23/2(+). The decay scheme deduced was interpreted in terms of shell model calculations, with a restricted basis of the f
5/2, p
3/2, p
1/2, g
9/2 orbitals outside a 56
28Ni core. 相似文献
890.
锂原子里德伯态能级的精细结构分裂 总被引:2,自引:2,他引:0
对锂原子的四体问题的哈密顿算符进行幂级数展开,通过计算原子实的 极化(包括偶极矩,四极矩至八级电极矩)对能级的贡献,同时考虑相对论效应和LS耦合以 及有效势的高阶修正,求得了锂原子里德伯态的能级位移和能级公式。用此公式计算N=5~1 2,L=4~9,J=L±1/2的相关的精细结构位移以及能级间隔,并与有关实验结果进行了比较 。 相似文献