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191.
O. Betbeder-Matibet M. Combescot 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,22(1):17-29
We study the interaction of an exciton with a distant metal, which is the simplest problem on interacting excitons: The semiconductor
and metal electrons being “different” species, we do not have to worry about the tricky consequences of Pauli exclusion between
identical carriers, which appear in any other problem on interacting excitons. We show how the exciton absorption, in the
presence of semiconductor-metal interaction, can be derived in a very simple and transparent way from an exciton diagram procedure,
provided that we use the appropriate exciton-metal interaction vertex, which contains the scattering from an exciton state
to another exciton state under a Coulomb excitation. We also show that the resolution of this problem using standard electron-hole
diagrams is dreadfully complicated at the lowest order in the semiconductor-metal interaction already, preventing a full calculation
of the exciton-metal coupling from this usual technique.
Received 26 February 2001 相似文献
192.
J. Bellessa V. Voliotis T. Guillet D. Roditchev R. Grousson X.L. Wang M. Ogura 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,21(4):499-505
We report on time-resolved microphotoluminescence experiments in a single GaAs/GaAlAs V-shaped quantum wire as a function
of optical excitation intensity. At low pump power we observe that excitons are localized in quantum boxes formed by the local
potential minima existing along the wire axis. As the pump power is increased, state filling of the lowest lying levels of
the boxes appears. When two carriers occupy the first excited level of the box, a very efficient Auger scattering occurs,
leading to a transfer of carriers from one box to another neighbouring one. The intradot Auger scattering time has been measured
and is of the same order of magnitude as the LA-phonon emission rate.
Received 5 February 2001 相似文献
193.
A. Komnik R. Egger 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,19(2):271-280
We study nonlinear transport for two coupled one-dimensional quantum wires or carbon nanotubes described by Luttinger liquid
theory. Transport properties are shown to crucially depend on the contact length L
c. For a special interaction strength, the problem can be solved analytically for arbitrary L
c. For point-like contacts and strong interactions, a qualitatively different picture compared to a Fermi liquid emerges, characterized
by zero-bias anomalies and strong dependence on the applied cross voltage. In addition, pronounced Coulomb drag phenomena
are important for extended contacts.
Received 28 July 2000 相似文献
194.
S. Pleutin A. Ovchinnikov 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,23(4):521-531
The static polarizability of cylindrical systems is shown to have a strong dependence on a uniform magnetic field applied
parallel to the tube axis. This dependence is demonstrated by performing exact numerical diagonalizations of simple cylinders
(rolled square lattices), armchair and zig-zag carbon nanotubes (rolled honeycomb lattices) for different electron-fillings.
At low temperature, the polarizability as function of the magnetic field has a discontinuous character where plateau-like
region are separated by sudden jumps or peaks. A one to one correspondence is pointed out between each discontinuity of the
polarizability and the magnetic-field induced cross-over between the ground state and the first excited state. Our results
suggest the possibility to use measurements of the static polarizability under magnetic field to get important informations
about excited states of cylindrical systems such as carbon nanotubes.
Received 29 March 2001 and Received in final form 8 August 2001 相似文献
195.
V.I. Yukalov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(1):83-91
An ensemble of resonance atoms is considered, which are doped into a medium with well developed polariton effect, when in
the spectrum of polariton states there is a band gap. If an atom with a resonance frequency inside the polariton gap is placed
into the medium, the atomic spontaneous emission is suppressed. However, a system of resonance atoms inside the polariton
gap can radiate when their coherent interaction is sufficiently strong. Thus the suppression of spontaneous emission for a
single atom can be overcome by a collective of atoms radiating coherently. Conditions when such collective effects can appear
and their dynamics are analysed.
Received 7 June 2000 相似文献
196.
CHEN Huanyin 《中国科学A辑(英文版)》2000,43(8):795-802
We introduce the notion of separativity of modules and show that many classes of modules possess the separativity. The present
work generalizes many known results. 相似文献
197.
通过建立具有平面近横向各向异性场的非晶态合金薄带及膜的磁畴结构模型,利用线性化Maxwell方程组及Landau-Lifshitz方程,推出了在高频交变磁场及外加面内轴向直流磁场Hex作用下的铁磁材料的与取向相关的磁导率表达式,得到了对方位角平均的相对磁导率及阻抗的计算式,导出了磁导率与张量磁化率分量间的关系,对材料磁导率的实部及虚部随Hex的变化进行了计算,并给出了对应的磁谱图.建立的磁导率与外磁场的理论关系可将Panina及Kraus给出的理论结果统一起来.
关键词:
非晶态合金薄带及膜
取向相关磁导率
GMI效应理论与计算
近横向各向异性场 相似文献
198.
Magdalena
widro-Pito Alicja Chromiec Marcin Zawadzki Renata Wietecha-Posuszny 《Molecules (Basel, Switzerland)》2022,27(13)
The present investigation utilised the quick and easy SPME/LC-MS method to determine selected narcotic substances and their metabolites in whole blood. The study included qualitative analysis and validation of the method. Analytes were determined in the linearity range of 25–300 ng/mL. The precision during and between days (in general CV < 13.41%), and the LOD which results in between 0.36 and 11.08 ng/mL, and the LOQ between 1.20 and 36.90 ng/mL were investigated. The validation results obtained, as well as the results of subsequent in-laboratory tests, confirmed the applicability of the method in the analysis of blood samples. An attempt to apply the method to the analysis of bone marrow samples has yielded promising results; however, more detailed studies are needed in this area. 相似文献
199.
5l.TheMedianFormulaAseveryoneknows:in6ABC,letal=BC,a2=CA,a3=AB,;)11,)n2,n13aremedian1inesseparatelyonthethreeedgesBC,CA,AB,tI1entheequalityistrueasfollowsTheequality(l)iscalledmedianformulaofQABC,andwecanobtainfrom(l)Inthispaper,wesha1lextendtheequality(l)and(2)to,l-simplexin)l-EuclideanspaceH.Itisobtainedthemedianformulaof)I-simplex,andusingthisformula.wegetsomein-equalities.Themedianformulaofn-simp1exisobtainedasfollows:TheoremlFork=1,2,--',It 1andl相似文献
200.
R. Caciuffo S. Melone G. Torquati V. G. K. M. Pisipati N. V. S. Rao 《Il Nuovo Cimento D》1986,7(3):421-436
Summary The results of a X-ray diffraction study, performed on N(p-n-pentyloxy benzylidene)p′-n-octylaniline (50.8) and N(p-n-pentyloxy
benzylidene)p′-n-decylaniline (50.10) are presented. The investigated compounds exhibit smecticB, smecticA and nematic phases in between solid and isotropic liquid phases. In addition, after a thermal cycle the 50.8 compound exhibits
a smecticG phase at room temperature. The interlayer and the in-plane intermolecular distances were obtained as functions of temperature
through all the mesophases. A phase coexistence has been observed during the solid to smecticB and the smecticB to smecticA phase transitions of the 50.8 compound. The nematic to smecticA phase transitions are found to be of second order for both compounds. Pretransitional effects due to cybotactic-cluster formation
in the nematic region are observed.
Riassunto Si presentano i risultati di uno studio effettuato mediante la diffrazione dei raggi X sul N(p-n-pentilossi benzilidene)p′-n-ottilanilina (50.8) e sul N(p-n-pentilossi benzilidene)p′-n-decilanilina (50.10). Tra le fasi solida ed isotropica i composti esaminati presentano le mesofasiS B ,S A e nematica. Inoltre, dopo un ciclo termico il composto 50.8 presenta una faseS G a temperatura ambiente. Sono state misurate le distanze tra i piani smettici e le distanze laterali tra le molecole in tutte le mesofasi in funzione della temperatura. Una coesistenza di fase è stata osservata durante le transizioni solido →S B eS B →S A del composto 50.8. Le transizioni nematico-S A sono risultate del second'ordine per entrambi i composti. Nelle fasi nematiche sono stati osservati effetti pretransizionali dovuti alla formazione di gruppi cibotattici.相似文献