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排序方式: 共有73条查询结果,搜索用时 11 毫秒
1.
A specially prepared Ga1−xAlxAs sample with a laterally graded alloy composition has allowed a novel investigation of resonance Raman scattering from the optical phonons. Instead of varying the exciting light energy, the resonance is probed by changing the alloy composition at fixed incident energy. Both incoming and outgoing resonances are observed at the direct gap of the alloy, free of the usual overwhelming photoluminescence background. 相似文献
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Tomasz Bujak Martyna Zagrska-Dziok Aleksandra Ziemlewska Zofia Nizio-ukaszewska Kamila Lal Tomasz Wasilewski Zofia Hordyjewicz-Baran 《Molecules (Basel, Switzerland)》2022,27(3)
Flowers are a natural source of bioactive compounds that not only have antioxidant, anti-inflammatory, and anti-aging properties, but can also be used as natural dyes. For this reason, nowadays plants are widely used to produce natural cosmetics and foods. In these studies, the properties of the water extracts of Papaver rhoeas L., Punica granatum L., Clitoria ternatea L., Carthamus tinctorius L., and Gomphrena globosa L., as bioactive, natural dyes, were investigated. Plant flower extracts were tested for their antioxidant (ABTS and DPPH radical methods) and anti-inflammatory effects by determining the ability to inhibit the activity of lipoxygenase and proteinase. The extracts were tested for their cytotoxic effect on skin cells, using Alamar Blue and Neutral Red tests. The ability to inhibit the activity of enzymes responsible for the destruction of elastin and collagen was also studied. Research has shown that extracts have no toxic effect on skin cells, are a rich source of antioxidants and show the ability to inhibit the activity of elastase and collagenase enzymes. P. rhoeas extract showed the strongest antioxidant properties with IC50 value of 24.8 ± 0.42 µg/mL and 47.5 ± 1.01 µg/mL in ABTS and DPPH tests, respectively. The tested plants are also characterized by an anti-inflammatory property, for which the ability to inhibit lipoxygenase at a level above 80% and proteinase at the level of about 55% was noted. Extracts from P. rhoeas, C. ternatea, and C. tinctorius show the strongest coloring ability and can permanently dye cosmetic products, without significant color changes during the storage of the product. 相似文献
5.
Krauter H Muschik CA Jensen K Wasilewski W Petersen JM Cirac JI Polzik ES 《Physical review letters》2011,107(8):080503
Entanglement is a striking feature of quantum mechanics and an essential ingredient in most applications in quantum information. Typically, coupling of a system to an environment inhibits entanglement, particularly in macroscopic systems. Here we report on an experiment where dissipation continuously generates entanglement between two macroscopic objects. This is achieved by engineering the dissipation using laser and magnetic fields, and leads to robust event-ready entanglement maintained for 0.04 s at room temperature. Our system consists of two ensembles containing about 10(12) atoms and separated by 0.5 m coupled to the environment composed of the vacuum modes of the electromagnetic field. By combining the dissipative mechanism with a continuous measurement, steady state entanglement is continuously generated and observed for up to 1 h. 相似文献
6.
E. Grodner A. A. Pasternak Ch. Droste T. Morek J. Srebrny J. Kownacki W. Płóciennik A. A. Wasilewski M. Kowalczyk M. Kisieliński R. Kaczarowski E. Ruchowska A. Kordyasz M. Wolińska 《The European Physical Journal A - Hadrons and Nuclei》2006,27(3):325-340
Lifetimes of yrast levels with spins Iπ = 23/2--43/2- in 131La populated in the 122Sn(14N, 5n) reaction at a beam energy of 70MeV are measured by the Doppler Shift Attenuation method. A model of side-feeding population
is presented. The model parameters are determined in an experiment based on the lineshape of γ-transitions from two highest
spin levels and from the intensity distribution along the yrast band. The properties of the h11/2 band in 131La are compared with the theoretical predictions obtained in the framework of the Core-Quasi-Particle Coupling and the self-consistent
Total Routhian Surface models. 相似文献
7.
K. Jankowski L. Meissner J. Wasilewski 《International journal of quantum chemistry》1985,28(6):931-942
Two new extensions of Davidson-type size-consistency collections to the case of quasidegenerate states are presented and applied to a simple model system in which the degree of quasidegeneracy can be continuously varied. The eight-electron model studied is a minimum basis set model involving eight hydrogen atoms in various spatial arrangements. The results are compared with the full CI energies as well as with those obtained with the CI-D, MRCI-D, coupled-pair, and linear coupled-pair methods. Two extensions of the Davidson correction recently devised by Paldus are also employed. The results indicate that all the Davidson-type corrections yield reliable correlation energies in the case of strong quasidegeneracies. 相似文献
8.
H.C. Liu C.Y. Song Z.R. Wasilewski J.A. Gupta M. Buchanan 《Infrared Physics & Technology》2009,52(6):285-288
Quantum-wells and quantum dots and related semiconductor nanostructures have been widely investigated for infrared devices. Here we propose a new general approach to make use of polar optical phonons in quantum-wells for infrared (IR) and terahertz (THz) detection. As the first example, we show the coupling of phonon and intersubband transition leading to Fano resonance in photocurrent spectra. We investigate the phenomenon experimentally in specially designed GaAs/AlGaAs quantum-well infrared photodetectors. Finally, we discuss the future research and potentials. 相似文献
9.
Janusz Wasilewski Jan F. Biernat 《Journal of inclusion phenomena and macrocyclic chemistry》1991,10(1):109-118
Lipophilic bis-substituted ester and ether derivatives of benzo-15-crown-5 have been synthesised. The correlation between the structure and potentiometric ion-selectivity has been studied in PVC membrane ion-selective electrodes. An ion-selective potassium sensitive electrode based on 4,5-bis (biphenyloxymethyl)benzo-15-crown-5 exhibited the best electrode properties. The detection limit was loga
K = -5.4; logK
K,Na
ppot = -3.5. The effect of the lipophilicity of neutral carriers upon electrode performance has been also discussed. 相似文献
10.
S. J. Cheng W. Sheng P. Hawrylak S. Raymond S. Studenikin A. Sachrajda Z. Wasilewski A. Babinski M. Potemski G. Ortner M. Bayer 《Physica E: Low-dimensional Systems and Nanostructures》2004,21(2-4):211
We present results of calculations and experiments on electron–hole complexes in InGaAs/GaAs self-assembled quantum dots in high magnetic field (B). Due to hidden symmetries, the chemical potential of an N-exciton system at special B fields becomes insensitive to the exciton number as well as the magnetic field. This results in plateau regions of high intensity in measured magneto-PL spectrum. Theoretical calculations using exact diagonalization techniques successfully explain the measured magneto-photoluminescence spectrum with B fields up to 28 T. 相似文献