排序方式: 共有12条查询结果,搜索用时 109 毫秒
1.
The properties of passive Q-switched short-cavity dye lasers (SCDL) and passive Q-switched distributed-feedback dye lasers (DFDL) are investigated theoretically by using rate-equation models. The calculations, in agreement with experimental results, predict a significant decrease of the pulse energy fluctuation and the pulse duration of both the SCDL and DFDL, when passive Q-switching is used. 相似文献
2.
We study the functionb(n, d), the maximal number of atoms defined byn d-dimensional boxes, i.e. parallelopipeds in thed-dimensional Euclidean space with sides parallel to the coordinate axes.
We characterize extremal interval families definingb(n, 1)=2n-1 atoms and we show thatb(n, 2)=2n
2-6n+7.
We prove that for everyd,
exists and
.
Moreover, we obtainb*(3)=8/9. 相似文献
3.
本文研究了在-170℃到+20℃温度范围内,Sb-Cs光阶极的光效应对温度的依赖关系。在极限波长附近,当温度下降时,发现灵敏度单纯地下降。在短波的地方,灵敏度在一个宽的温度范围内与温度无关;只有到极低温度时,灵敏度才很快下降。 相似文献
4.
5.
The concept of a localk-coloring of a graphG is introduced and the corresponding localk-Ramsey numberr
loc
k
(G) is considered. A localk-coloring ofG is a coloring of its edges in such a way that the edges incident to any vertex ofG are colored with at mostk colors. The numberr
loc
k
(G) is the minimumm for whichK
m
contains a monochromatic copy ofG for every localk-coloring ofK
m
. The numberr
loc
k
(G) is a natural generalization of the usual Ramsey numberr
k
(G) defined for usualk-colorings. The results reflect the relationship betweenr
k
(G) andr
loc
k
(G) for certain classes of graphs.This research was done while under an IREX grant. 相似文献
6.
G. Molnár ZS. Révay Á. Veres A. Simonits H. Rausch 《Journal of Radioanalytical and Nuclear Chemistry》1993,167(1):133-137
The restart of the recently upgraded research reactor in Budapest is foreseen at the end of this year. A number of fast, thermal and cold neutron beams will serve for research, industrial and educational activities. One of the cold neutron guide end positions will be utilized for neutron capture prompt gamma-ray activation analysis (PGAA). Further development of the PGAA method as well as new applications in environmental research, biology and medicine are planned. 相似文献
7.
Employing the Foldy–Wouthuysen transformation, it is demonstrated straightforwardly that the first and second Chern numbers are equal to the coefficients of the 2+1 and 4+1 dimensional Chern–Simons actions which are generated by the massive Dirac fermions coupled to the Abelian gauge fields. A topological insulator model in 2+1 dimensions is discussed and by means of a dimensional reduction approach the 1+1 dimensional descendant of the 2+1 dimensional Chern–Simons theory is presented. Field strength of the Berry gauge field corresponding to the 4+1 dimensional Dirac theory is explicitly derived through the Foldy–Wouthuysen transformation. Acquainted with it, the second Chern numbers are calculated for specific choices of the integration domain. A method is proposed to obtain 3+1 and 2+1 dimensional descendants of the effective field theory of the 4+1 dimensional time reversal invariant topological insulator theory. Inspired by the spin Hall effect in graphene, a hypothetical model of the time reversal invariant spin Hall insulator in 3+1 dimensions is proposed. 相似文献
8.
OG Khvostenko ZS Yarullina NM Shishlov VE Rusin 《Rapid communications in mass spectrometry : RCM》1999,13(12):1091-1097
A correlation between the energies of electronic singlet transitions in benzodiazepines and their biological activity, which was revealed earlier by means of negative ion mass spectrometry with resonance electron capture, has been verified with a UV absorption spectroscopy investigation. Also, it has been noted that the energies of electronic singlet transitions in benzodiazepines are close in value to the ionization energies of atoms Cs, Rb, K, Na, Li and Tl, the cations of which are known to play an important role in nerve cell excitation processes. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
9.
In this report the necessary conditions for optimal non‐smooth control of rigid body mechanical systems with multiple impacts will be stated in accordance with Pontryagin's Minimum Principle. Criteria based on the Weierstrass‐Erdmann (WE) conditions and contemporary impact theory will be established in order to assess the optimality of an impact.The determination of post‐impact state and costate values from the pre‐impact values will be possible in some cases. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
10.
The kinetic behavior of the autocatalytic oxidation of hemin by acidic bromate was studied spectrophotometrically. The reaction was shown to differ significantly from both the acidic decomposition and the direct bromination of hemin. The dependence of its maximal rate on the reactant concentrations was established as v = k[hemin]0.8[BrO?3][H+]1.2. The value of the net rate constant was determined at two different ionic strengths. In the reaction path BrO.2 radicals rather than elementary bromine play a crucial role. A mechanism is presented which takes into account the results of bromate chemistry as described for the Belousov–Zhabotinsky (BZ) reaction completed with the appropriate steps of hemin. On the basis of the suggested mechanism, model calculations were carried out which allowed to give an estimation for the rate constant of the reaction between hemin and BrO.2 radicals. The results of computations account for the main experimental features of the reaction. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 503–509, 2006 相似文献