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101.
持黑体光壁腔观点用几何光学方法模拟黑体,得一柱隙锥齿型黑体模拟器,写出黑体数学模拟式,给出适用模拟器的身体参数。 相似文献
102.
103.
采用有限元方法研究了结构在热载荷作用下变形与热传导之间的耦合特性.分析表明,结构变形较小,非线性效应很弱时,变形对材料的热传导系数影响很小,对结构的温度分布几乎没有影响;当变形增大,非线性效应增强时,变形对材料的热传导特性影响显著,热载荷作用下结构的温度变化和变形与现行不考虑热-机耦合效应所得结果产生明显差异.因此,为实现压电智能结构形状(振动)的精确控制,分析及实施控制时须考虑热-机耦合及变形对热传导系数的影响. 相似文献
104.
Gold-doped palladium clusters, Au2Pdn (n = 1~4), are investigated using the density functional method B3LYP with relativistic effective core potentials (RECP) and LANL2DZ basis set. The possible geometrical configurations with their electronic states are determined, and the stability trend is investigated. Several low-lying isomers are determined, and many of them are in electronic configurations with a high-spin multiplicity. Our results indicate that the palladium-gold interaction is strong enough to modify the known pattern of bare palladium clusters, and the lower stability as the structures grow in size. The present calculations are useful to understanding the enhanced catalytic activity and selectivity gained by using gold-doped palladium catalyst. 相似文献
105.
Hamilton’s theory of turns for the group SU(2) is exploited to develop a new geometrical representation for polarization optics.
While pure polarization states are represented by points on the Poincaré sphere, linear intensity preserving optical systems
are represented by great circle arcs on another sphere. Composition of systems, and their action on polarization states, are
both reduced to geometrical operations. Several synthesis problems, especially in relation to the Pancharatnam-Berry-Aharonov-Anandan
geometrical phase, are clarified with the new representation. The general relation between the geometrical phase, and the
solid angle on the Poincaré sphere, is established. 相似文献
106.
Differential geometry of chemically reacting systems 总被引:1,自引:0,他引:1
This paper is a detailed differential geometrical study of chemically reacting systems. In particular the following coordinate-free properties of chemically reacting systems are obtained: 1) the general solution of the intrinsic reaction coordinate (IRC) (henceforth referred to as meta-IRC), 2) extended definitions of the Hessian matrix and normal vibrations at any non-equilibrium point on the surface, and 3) clarification of the close connection between the geometry of meta-IRC and the geography of the surface at a transition point. The theory is elucidated using a model potential surface. 相似文献
107.
Rudolf Beran 《Annals of the Institute of Statistical Mathematics》1996,48(1):1-15
Suppose X
n
is an observation, or average of observations, on a discretized signal
n
that is measured at n time points. The random vector X
n
has a N(
n
, 2
n
I) distribution, the mean and variance being unknown. Under squared error loss, the unbiased estimator X
n
of
n
can be improved by variable-selection. Consider the candidate estimator
n
(A) whose i-th component equals the i-th component of X
n
whenever i/(n+1) lies in A and vanishes otherwise. Allow the set A to range over a large collection of possibilities. A C
p
-estimator is a candidate estimator that minimizes estimated quadratic loss over A. This paper constructs confidence sets that are centered at a C
p
-estimator, have correct asymptotic coverage probabiligy for
n
, and are geometrically smaller than or equal to the competing confidence balls centered at X
n
. The asymptotics are locally uniform in the parameters (
n
, 2
n
). The results illustrate an approach to inference after variable-selection. 相似文献
108.
Ezzat T. M. Selim 《Journal of Chemical Sciences》1982,91(4):359-369
Using mass spectrometric technique, the effect of geometrical isomerism on the first and higher appearance energy values for
C4H3
+, C4H7
+ and C3H,3
+ ions obtained from cis-2-butene andtrans-2-butene is reported. The structure in the ionization efficiency curves (studied for 9 eV above threshold) for the same ions
obtained from the two isomers is reported and compared. It is believed that at threshold C4H7
+ fragment is formed from the two isomers as methallyl ion. For C3H3
+ fragment formed from the cw-isomer at threshold the proposed structure is the propargyl ion with ΔHf equal to 279-4 kcal/mole while for that ion obtained fromtransisomer the proposed structure is the allenyl ion with ΔHf equal to 296.6 kcal/mole. 相似文献
109.
Zheng Bo Jian Hua Yan Xiao Dong Li Yong Chi Bruno Chéron Ke Fa Cen 《Plasma Chemistry and Plasma Processing》2007,27(6):691-700
The dependence of gliding arc gas discharge characteristics, including gas flow field, arc column motion and volatile organic
compounds (VOCs) decomposition performance, on reactor configuration parameters was investigated based on numerical simulation
and laboratory experimental findings. For a given supply voltage (10 kV) and a certain nozzle outlet diameter (1.5 mm), increasing
the electrodes gap (1–4 mm) or decreasing vertical distance between electrode throat and nozzle outlet (25–10 mm) will increase
the gas flow rate through the electrode throat, the gas velocity in the plasma region, the arc column velocity, the maximum
attainable position of the arc column and the electrical power consumption, also, higher VOCs decomposition rate and lower
specific energy requirement are observed according to the n-butane and toluene decomposition experiments. 相似文献
110.
An analytical expression is presented for describing the electrostatic interaction forces between various shaped particles having mutual orientations. The expression is derived by applying the surface integration method, which is a generalization of the Derjaguin summation procedure. Based on previous theoretical considerations it is possible to calculate the electrostatic interaction force between regularly shaped bodies (both convex or concave in the vicinity of their contact point) by multiplying the interaction energy derived for paralled plates with the corresponding geometric factor. The forces acting between two equal shaped ellipsoids are described and discussed, considering three different limiting orientations, the parallel, the perpendicular, and the contact of the edges' orientation. 相似文献