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1.
Let H and K be indefinite inner product spaces. This paper shows that a bijective map φ:B(H)→B(K) satisfies φ(AB B A) =φ(A)φ(5) φ(B) φ(A) for every pair A,B ∈B(H) if and only if either φ(A) = cU AU for all A or φ(A) = cUA U for all A; φsatisfies φ(AB A) = φ(A)φ(B) φ(A) for every pair A,B ∈B(H) if and only if either φ(A) = UAV for all A or φ(A) = UA V for all A, where A denotes the indefinite conjugate of A, U and V are bounded invertible linear or conjugate linear operators with U U = c-1I and V V = cI for some nonzero real number c. 相似文献
2.
We show that an electron confined to a single finite parabolic quantum well in crossed electric and magnetic fields can behave as a double quantum well system. The magnetic field is parallel to the heterostructure layers and the electric field is perpendicular to those. For a suitable choice of both fields and quantum well width, the electron can be confined to a double quantum well effective potential that is very similar to the electronic potential model for diatomic molecules. The double quantum well spectrum is calculated using a numerical algorithm based on semiclassical methods. A physical interpretation of this quantum system is given based on the analogy to the electrons bound to diatomic molecules. 相似文献
3.
Effects of Substrate Temperature on Helium Content and Microstructure of Nanocrystalline Titanium Films
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Helium-charged nanocrystalline titanium films have been deposited by HeAr magnetron co-sputtering. The effects of substrate temperature on the helium content and microstructure of the nanocrystalline titanium films have been studied. The results indicate that helium atoms with a high concentration are evenly incorporated in the deposited titanium films. When the substrate temperature increases from 60℃ to 350℃ while the other deposition'parameters are fixed, the helium content decreases gradually from 38.6 at.% to 9.2at.%, which proves that nanocrystalline Ti films have a great helium storage capacity. The 20 angle of the Bragg peak of (002) crystal planes of the He-charged Ti film shifts to a lower angle and that of (100) crystal plane is unchanged as compared with that of the pure Ti film, which indicates that the lattice parameter c increases and a keeps at the primitive value. The grain refining and helium damage result in the diffraction peak broadening. 相似文献
4.
用A的不变子空间作参数,给出了算子方程AX=XAX的全部解。当A是单射或稠值域时,或者当A是正规算子时,给出了算子方程AX=XA=XAX的全部解。我们还给出正规算子X是算子方程AX=XZ=XAX的解的充分必要条件。 相似文献
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Communicated by
C. Dafermos 相似文献
7.
Benjamin Falk Santiago M. Vallinas James V. Crivello 《Journal of polymer science. Part A, Polymer chemistry》2003,41(4):579-596
This article describes the development of optical pyrometry (OP) as a new analytical technique for the continuous monitoring of the progress of both free‐radical and cationic photopolymerizations. The method is rapid, reproducible, and very easy to implement. A temperature profile of a photopolymerization can be obtained. Preliminary studies have shown that the temperatures of some polymerizing monomers can easily reach temperatures in excess of 250 °C. The effects of the mass and reactivity of the monomer, light intensity, structures, and concentrations of the photoinitiators and monomers as well as the presence or absence of oxygen on various free‐radical and cationic photopolymerizations were examined with this method. Coupling of real‐time infrared spectroscopy with OP provides a convenient method for simultaneously monitoring both the chemical conversion and the temperature of a photopolymerization. This combined technique affords new insights into the effects of temperature‐induced autoacceleration on the course of photopolymerizations. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 579–596, 2003 相似文献
8.
由于腔模与激子对压力的依赖关系不同,所以可以选择不同的压力使激子和光场处于不同的耦合状态,从而实现对耦合的调谐。利用这种办法,我们观测到了代表激子与光场强耦合作用的Rabi分裂。由于在我们现有样品结构中压力对激子本征行为的影响很小,与以前报道的温度、电场等调谐方式相比,这种调谐方法不仅可以有效地调谐半导体微腔内激子与腔模的耦合程度,而且能够保持激子的本征性质在整个调谐过程中基本不变。这有助于研究在强耦合过程中激子极化激元的本征性质。将实验结果与压力下激子与腔模耦合理论进行拟合,得出了正确的Rabi分裂值。 相似文献
9.
激光沉积超导薄膜过程中出射粒子速度的飞行时间谱分析 总被引:1,自引:1,他引:0
采用飞行时间谱技术,测量了准分子激光烧蚀沉积高温超导薄膜过程中,由靶面出射粒子的飞行速度。研究了粒子速度与充氧压及其激光能量密度的关系。讨论了高能粒子在薄膜原位低温外延生长中的作用。 相似文献
10.