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1.
We propose a scheme to localize a two-level atom inside a classical standing wave field conditioned upon the measurement of the frequency of a weak probe field at resonance excitation of a two-level atomic system. Inside the classical standing wave field, the interaction between the atom and the field is position-dependent due to the Rabi frequency of the driving field; hence, as the absorption frequency of the probe field is measured, the position of an atom inside the classical standing wave field will be determined. The effects of atomic parameters on atom localization are then discussed. 相似文献
2.
R. Kheradmand M. Sahrai H. Tajalli G. Tissoni L. A. Lugiato 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(1):107-112
We present here a method for selecting optical patterns in a passive
semiconductor microresonator, by using a spatial perturbation. A pattern is
spontaneously generated in the system, and a switching beam causes this
pattern to rotate even if the power in the switching beam is much lower than
the power in the pattern. Thus, an all optical switch is realized, that
operates at low light levels. 相似文献
3.
Fully printed flexible audio system on the basis of low‐voltage polymeric organic field effect transistors with three layer dielectric
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Georg C. Schmidt Daniel Höft Katherina Haase Maxi Bellmann Bahman Kheradmand‐Boroujeni Tomi Hassinen Henrik Sandberg Frank Ellinger Arved C. Hübler 《Journal of Polymer Science.Polymer Physics》2015,53(20):1409-1415
Fully mass printed, flexible and truly polymeric organic field effect transistors consisting of a three layer dielectric made of CYTOP (low‐k), PVA (intermediate) and P(VDF‐TrFE‐CTFE)(high‐k) are introduced. Gravure‐, flexo‐and screen printing were selected as highly productive manufacturing technologies. These OFETs work at strongly reduced voltages and show high field effect mobility (µ = 0.2 cm2/Vs) and remarkable good bias stress stability at very high current density (50 µA/mm). Fully printed OFETs are used for the realization of ring oscillators working in the kHz regime at reduced supply voltage (10 V). In combination with printed fully polymeric piezoelectric loudspeakers, this work shows for the first time fully printed flexible audio systems. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1409–1415 相似文献
4.
M. Bache F. Prati G. Tissoni R. Kheradmand L.A. Lugiato I. Protsenko M. Brambilla 《Applied physics. B, Lasers and optics》2005,81(7):913-920
We study theoretically a broad-area vertical cavity surface emitting laser (VCSEL) with a saturable absorber. We show numerically
the presence of cavity solitons in the system: they exist as solitary structures formed through a modulationally unstable
homogeneous lasing state that coexists with a background with zero intensity. Such a peculiar scenario endows the solitons
with unique properties compared to cavity solitons in most previously studied optical systems. In particular, these solitons
do not as such rely on a proper phase of the addressing pulses to be either created or deleted. We show that exciting and
deleting the solitons depend crucially on whether a threshold in the soliton peak has been reached. 相似文献
5.
The volatile constituents in the essential oil of Pelargonium quercetorum Agnew., growing wild in Kurdistan, Iran were investigated through GC and GC/MS technique. Twenty-six compounds, representing 21 (80.77%) of the total oil were identified. The main components were: alpha-pinene (25.28%), alpha-fenchyl acetate (20.63%), limonene (9.94%), beta-caryophyllene (8.20%), camphene (4.31%), delta-cadinene (3.32%), beta-pinene (3.21%), alpha-amorphene (2.80%), valencene (2.73%), ledene (2.25%) and p-cymene (1.63%). 相似文献
6.
Nitride semiconductors and their alloys recently have versatile applications as high-power and high-efficiency electro optical
devices duo to their high thermal stability, direct transition and wide bang-gap. Nanostructure light emitting diodes of these
materials have an emission spectrum from infrared to ultraviolet. In this paper, besides simulating a nanostructure nitride
semiconductor LED, such as multi quantum well nitride LEDs, the effect of temperature on the recombination rate has been investigated. 相似文献
7.
8.
Solvent bar microextraction combined with high‐performance liquid chromatography for preconcentration and determination of pramipexole in biological samples
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Ensieh Ghasemi Salim Kheradmand Orkideh Ghorban Dadrass 《Biomedical chromatography : BMC》2014,28(4):486-491
A simple, rapid and sensitive analytical method for preconcentration and determination of pramipexole in different biological samples has been developed using solvent bar microextraction (SBME) combined with HPLC‐UV. The target drugs were extracted from 10 mL of basic aqueous sample solution into an organic extracting solvent located inside the pores of a polypropylene hollow fiber, then back‐extracted into an acidified aqueous solution in the lumen of the hollow fiber. In order to obtain high extraction efficiency, the effect of different variables on the extraction efficiency was studied simultaneously using an experimental design. The experimental parameters of SBME were optimized using a Box–Behnken design after a Plackett–Burman screening design. Under the optimized conditions, an enrichment factor up to 96 was achieved and the relative standard deviation of the method was 4.64% (n = 5). The linear range was 0.05–2000 µg/L with a correlation coefficient (r) of 0.987. Finally, the applicability of the proposed method was evaluated by extraction and determination of pramipexole in plasma and urine samples. The results indicated that SBME method has excellent clean‐up and high preconcentration factor and can serve as a simple and sensitive method for analysis of pramipexole in biological samples. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
9.
Amanj Kheradmand Ahmad Ramazani Saadat Abadi Farhad Khorasheh Morteza Baghalha Hiva Bahrami 《Polymer Science Series B》2016,58(3):271-277
In this study, we have reported the preparation of bi-supported Ziegler-Natta catalysts using magnesium ethoxide and graphene oxide as support. The polymerization process was carried out in slurry phase using triisobutylaluminum as a co-catalyst.The XRD analysis of TiCl4/graphene oxide/Mg(OEt)2 catalyst demonstrated that the space between the layers of graphene oxide had increased to 0.2 nm.The catalyst was characterized by XPS, BET, BJH, SEM, and TGA. The catalyst activity was studied for various Al/Ti molar ratios, and the catalyst activity was optimum at Al/Ti molar ratio of 315. 相似文献
10.
Effects of nano graphene oxide as support on the product properties and performance of Ziegler–Natta catalyst in production of UHMWPE
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Amanj Kheradmand Ahmad Ramazani S.A. Farhad Khorasheh Morteza Baghalha Hiva Bahrami 《先进技术聚合物》2015,26(4):315-321
The synthesis of mono‐ and bi‐supported Ziegler–Natta catalysts using magnesium etoxide Mg(OEt)2 and graphene oxide (GO) as catalyst support for production of Ultra High Molecular Weight Polyethylene (UHMWPE) is reported in this investigation. Nano‐graphene oxide was prepared by the modified Hummer's method and its structure was analyzed by XRD and FTIR indicating the presence of hydroxyl groups on graphene oxide and the formation of an exfoliated structure. The activity of TiCl4/Mg(OEt)2, TiCl4/Mg(OEt)2‐GO, and TiCl4/GO catalysts in terms of grams of PE produced per mmol of Ti per hour was experimentally obtained for catalysts with different ratios of co‐catalyst (triisobutylaluminium) to TiCl4. For all three series of catalysts, the activity curve showed an optimum point at a specific Al/Ti molar ratio. Catalyst activity was highest for TiCl4/Mg(OEt)2 and lowest for TiCl4/GO. The characterization of UHMWPE products indicated that the viscosity average molecular weight (Mv) was highest for the polymer produced by TiCl4/Mg(OEt)2 and lowest for the polymer produced by TiCl4/GO. Furthermore, thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and mechanical tensile testing were conducted on the prepared polymers indicating that the polymer produced by TiCl4/GO had the highest thermal and mechanical properties, while these properties were at their minimum for polymers produced by TiCl4/Mg(OEt)2. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献