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991.
V. K. Abrahamyan N. H. Hakobyan V. M. Aroutiounian V. G. Babajanyan H. L. Margaryan D. L. Hovhannisyan A. T. Poghosyan D. K. Pokhsraryan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2009,44(2):84-90
We present results of studies of main characteristics of electrically-controlled retarders fabricated on the basis of planar- and twist-oriented liquid crystals (LC). The investigated characteristics are time of switching and the calibration curve of controllable phase incursion. Computer simulation and numerical calculations of the processes of LC director reorientation in an external electric field have been performed. Based on LabView software a special program is constructed for computer control of the shape, frequency, and amplitude of the external voltage applied to LC cell. An experiment has been implemented on realization, with use of this program, of the prescribed phase retardation of an optical beam. Calculated results agree with experimental data. 相似文献
992.
993.
994.
Dmitrij Bondarev Jiří Zedník Ivana Šloufová Ahmed Sharf Marek Procházka Jiří Pfleger Jiří Vohlídal 《Journal of polymer science. Part A, Polymer chemistry》2010,48(14):3073-3081
High‐regioregular poly{3‐[6‐(1‐methylimidazolium‐3‐yl)hexyl]thiophene‐2,5‐diyl bromide}, PMHT‐Br, has been prepared by reaction of high‐regioregular (above 92%) poly[3‐(6‐bromohexyl)thiophene‐2,5‐diyl] with 1‐methylimidazole. PMHT‐Br is soluble in water and water miscible solvents such as methanol, DMSO and shows solvatochromism; λmax (nm): 423 (H2O); 435 (MeOH); 452 (DMSO). Increased absorption band broadening observed for aqueous solution as well as NMR spectra in D2O suggests a micelle‐like structure of PMHT‐Br molecules in these solutions: poly(3‐hexylthiophene) core and 1‐methylimidazolium bromide shell. Despite the disturbing effect of ionic groups, the solid‐state PMHT‐Br shows absorption maximum at 520 nm, the band edge at 660 nm (ca. 1.9 eV), and fluorescence emission with maximum at 635 nm, in a good agreement with the polymer regioregularity. Fluorescence emission maxima: λem (nm): 598 (H2O); 562 (MeOH); 574 (DMSO), occur in a vicinity of corresponding adsorption band edges. Plot of electrical conductivity of PMHT‐Br (measured under the dynamic vacuum conditions, 5 × 10?5 Pa) versus 1/T shows a break at about 70 °C same as the temperature dependence of λmax of the solid PMHT‐Br. These breaks indicate an increase in the mobility of polymer segments and ions within PMHT‐Br; however, a thermal analysis did not provide solid evidence for it. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3073–3081, 2010 相似文献
995.
996.
Alexander Belyaev 《Pramana》2009,72(1):143-160
Large Hadron Collider (LHC) has a great chance to finally reveal supersymmetry which remains a compelling theory for over
30 years in spite of lack of its discovery. It might be around the corner the present LHC era with sensitive dark matter search
experiments and international linear collider hopefully coming up in the near future.
相似文献
997.
Shankari V. Rajagopal Kurt M. Fujiwara Ruwan Senaratne Kevin Singh Zachary A. Geiger David M. Weld 《Annalen der Physik》2017,529(8)
Ultracold atomic physics experiments offer a nearly ideal context for the investigation of quantum systems far from equilibrium. We describe three related emerging directions of research into extreme non‐equilibrium phenomena in atom traps: quantum emulation of ultrafast atom‐light interactions, coherent phasonic spectroscopy in tunable quasicrystals, and realization of Floquet matter in strongly‐driven lattice systems. We show that all three should enable quantum emulation in parameter regimes inaccessible in solid‐state experiments, facilitating a complementary approach to open problems in non‐equilibrium condensed matter. 相似文献
998.
研究了脉冲HF激光与水柱表面相互作用下电信号的产生过程。电信号显示了与激光能量线性相关的峰值间有时间间隔的两峰结构,且第二个尖峰在水柱底部的蒸汽腔塌缩后出现。实验还显示电信号的幅值和激光脉冲照射过程中是否存在膨胀和挤压的薄水层密切相关。如果在电池上边缘和石英平板(石英板紧邻电池,并与水柱上表面相接)之间存在一薄水层,电信号强度会增加10倍。 相似文献
999.
Shyjumon Ibrahimkutty Daniel Issenmann Stefan Schleef Anke‐Susanne Müller Yves‐Laurent Mathis Biliana Gasharova Erhart Huttel Ralph Steininger Jörg Göttlicher Tilo Baumbach Albrecht Bartels Christof Janke Anton Plech 《Journal of synchrotron radiation》2011,18(4):539-545
A high‐repetition‐rate pump–probe experiment is presented, based on the asynchronous sampling approach. The low‐α mode at the synchrotron ANKA can be used for a time resolution down to the picosecond limit for the time‐domain sampling of the coherent THz emission as well as for hard X‐ray pump–probe experiments, which probe structural dynamics in the condensed phase. It is shown that a synchronization of better than 1 ps is achieved, and examples of phonon dynamics of semiconductors are presented. 相似文献
1000.
Yoshiteru Amemiya Tomohiro Tokunaga Yuichiro Tanushi Shin Yokoyama 《Optical Review》2009,16(3):247-251
Electric-field drive optical modulators using a Si ring resonator were fabricated on silicon-on-insulator (SOI) wafers. The
fabricated resonators consisted of Si waveguides with width and thickness of 1.0 and 0.3 μm, respectively. In order to induce
the linear electro-optic (EO) effect in the Si core layer, the strain was applied by covering the layer with Si3N4 film (0.26 μm thick) deposited by low pressure chemical vapor deposition (LPCVD) at 750 °C. The vertical electric-field was
applied to the Si waveguide through the top and bottom cladding layers, and the optical output from the drop port at the resonance
wavelength was measured. At a wavelength of 1501.6 nm, the optical modulation of 33% was obtained at 200V (electric-field
at the silicon surface ∼3 × 105 V/cm, nearly the breakdown field). The resonance wavelength was shifted toward the short wavelength side by applying both
positive and negative voltages, this shift was explained by carrier concentration modulation. The linear EO effect in the
Si core layer was not observed, presumably because the strain in the Si core layer was too small. 相似文献