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1.
L. Arizmendi C. de las Heras F. Jaque A. Suchocki S. Kobyakov T.P.J. Han 《Applied physics. B, Lasers and optics》2007,87(1):123-127
Polymer stabilized cholesteric texture cells with various chiral and monomer concentrations were fabricated. Electro-optical measurement indicates that the chiral concentration and the monomer concentration significantly influence the hysteresis, threshold voltage and field-on and field-off response times of the cell. The chiral dopant is found to increase the hysteresis width and to decrease the field-off response time of the cell. The monomer is found to decrease the hysteresis width and to increase the field-off response time of the cell. The field-on response time is independent of the monomer concentration and the chiral concentration of the cell. A thinner cell has a smaller hysteresis width. PACS 61.30.-v; 42.70.Df; 42.79.Kr 相似文献
2.
Electro-optical properties of polymer stabilized cholesteric liquid crystal film 总被引:1,自引:0,他引:1 下载免费PDF全文
Liquid crystals (LCs) and polymers are extensively used in various electro-optical applications.In this paper,normal mode polymer stabilized cholesteric LC film is prepared and studied.The effects of chiral dopant and monomer concentrations on the electro-optical properties,such as contrast ratio,driving voltage,hysteresis width and response time,are investigated.The reasons of electro-optical properties influenced by the concentrations of the materials are discussed.Through the proper material recipe,the electro-optical properties of polymer stabilized cholesteric LC film can be optimized. 相似文献
3.
《Phase Transitions》2012,85(4):364-370
Pyrimidine multicomponent mixture used as a base for the preparation of ferroelectric liquid crystalline mixtures after doping with chiral dopants was tested in the aim of establishing the tilt angle dependence on the concentration of chiral dopant. The compounds being components of this mixture were doped with the same chiral dopant to check the influence of their structure on the tilt angle of ferroelectric mixtures. 相似文献
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Blue phase (BP) temperature range of a chiral nematic liquid crystal (LC) mixture is dependent upon the host nematic LC chemical structure and chiral dopant concentration. In this study, we investigated BP phase transition behaviour and helical twisting power (HTP) using three chiral dopant concentrations of cyano compound chiral nematic LC mixtures incorporating three two-ring core structures in the host nematic LCs. The effect of the host nematic LC core structure, HTP and chiral dopant concentrations were considered on BP temperature ranges, for two types of complete BPI and BPII without isotropic phase (Iso) and two types of coexistence state of BPI+Iso and BPII+Iso. 相似文献
5.
The full Landau potential was determined for a
ferroelectric liquid crystal doped with varying concentrations of the chiral dopant R1011 and its enantiomer S1011. A multi-curve
fitting procedure using temperature and electric field dependent tilt angle and polarization data was employed to the generalized
Landau model of ferroelectric liquid
crystals. From this analysis the three Landau coefficients as well as the polarization-tilt coupling parameters were obtained
as a function of dopant concentration and configuration. It is shown that the two most varied
parameters are those of the first Landau coefficient α and the
(chiral) linear polarization-tilt coupling constant C. The effect on the
first Landau term is equivalent for the two dopants of opposite handedness
indicating its achiral nature, while the effect on the (chiral) bilinear
coupling term differs for the R1011 and S1011 dopant, increasing and
decreasing the coupling between tilt and polarization respectively. This
difference in the bilinear coupling term quantifiably evidences that the
R1011 dopant increases and S1011 dopant reduces the inherent chirality in
this system. 相似文献
6.
The influence of the doping level on the effect of the temperature bistability in a silicon wafer upon radiative heat transfer between the wafer and the elements of the heating system is studied. Theoretical transfer characteristics are constructed for a silicon wafer doped with donor and acceptor impurities. These characteristics are compared with the transfer characteristics obtained during heating and cooling of wafers with the hole conduction (with dopant concentrations of 1015, 2 × 1016, and 3 × 1017 cm?3) and electron conduction (with impurity concentrations of 1015 and 8 × 1018 cm?3) in a thermal reactor of the rapid thermal annealing setup. It is found that the width and height of the hysteresis loop decrease with increasing dopant concentration and are almost independent of the type of conduction of the silicon wafer. The critical value of the impurity concentration of both types is 1.4 × 1017 cm?3. For this concentration, the loop width vanishes, and the height corresponds to the minimal value of the temperature jump (~200 K). The mechanism of temperature bistability in the silicon wafer upon radiative heat transfer is discussed. 相似文献
7.
A randomly inhomogeneous composite consisting of two, ferromagnetic and nonmagnetic (para-or diamagnetic), phases is considered.
The dependence of the effective permeability of the composite on the concentration of the ferromagnetic phase and on the applied
magnetic field is found for the case of the negligible hysteresis loop. When the hysteresis loop is appreciable, the remanent
magnetization as a function of the ferromagnet concentration is calculated. 相似文献
8.
The magnetic properties, such as initial permeability and hysteresis loop properties of the chromium substituted Li–Sb ferrite system have been investigated. The SEM micrographs reveal the microstructure of the samples. The initial permeability is observed to decrease with the increase of chromium concentration. Frequency variation of permeability indicates that for all samples the resonance peak due to domain wall oscillations is at a frequency above 15 MHz. The hysteresis loop parameters have been calculated from the hysteresis loop studies. The magnetic parameters are observed to decrease with higher level of substitution. 相似文献
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PLZT12/40/60 ceramics doped with different Mn content were prepared by a conventional mixed oxide method. The shrinkage of some local crystal cells was confirmed by XRD diffraction. The effect of Mn doping on the hysteresis loop was investigated. A peculiar double-hysteresis-like loop was found and various possible mechanisms were discussed. Random local strains caused by shrunk crystal cells can satisfactorily explain the double hysteresis characteristics. The dependence of the double-hysteresis-like loops on temperature was also investigated. Due to the heat activation of polar moments in shrunk crystal cells, the double-hysteresis-like loops can transform into a normal one when the temperature is rising. 相似文献
12.
利用大学物理实验中的光杠杆法测定金属丝弹性模量的原理和设备,对具有超弹性的NiTi丝的弹性滞后环进行了测定结果表明,此种方法可以很好地测定NiTi丝的弹性滞后环,而且操作简单使用方便,是一种非常有效的测定金属细丝弹性滞后环的方法. 相似文献
13.
利用磁控溅射方法制备多层膜后,再经热处理得到Co-Pt-C颗粒膜.热处理使Co-Pt颗粒从非晶相转向fcc CoPt3和fct CoPt稳定有序相,C则保持非晶态.Pt成分占Co,Pt总体积的70%时,膜的矫顽力Hc可超过400?kA/m.C插层厚度为0.2—0.6nm时,Hc最大,且在磁滞回线上出现“肩膀”.分析认为这是由于存在两个磁性不同的Co-Pt晶相,受C成分比的影响,使它们之间的耦合性质和强度不同造成的.
关键词:
Co
Pt
C
磁滞回线
颗粒膜 相似文献
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Shadrin E. B. Il’inski? A. V. Sidorov A. I. Khanin S. D. 《Physics of the Solid State》2010,52(11):2426-2433
A phenomenological model has been proposed for the formation of the major thermal hysteresis loop of optical parameters upon
the semiconductor-metal phase transition in vanadium oxide nanocomposites. It has been demonstrated that the effects associated
with the influence of nanocrystallite sizes on the phase transition temperature in an individual nanocrystallite, which is
determined by the width of the elementary hysteresis loop and the position of the phase equilibrium temperature on the temperature
scale, manifest themselves in the form of pronounced features in the loop shape. In particular, the size effects for VO2 polycrystalline films are observed in the formation of a trapezoidal shape of the optical thermal hysteresis loop with a
wide lower base, whereas these effects for nanocomposites based on porous glasses with VO2 nanocrystals are revealed in the form of the optical hysteresis loop with a narrow lower base (wide upper base). The proposed
model also explains the symmetric shape of the major hysteresis loop for vanadium oxide nanocomposites based on opals. The
size effects in opal nanocomposites with strictly fixed sizes of pores and, therefore, nanocrystallite sizes manifest themselves
in the form of well-defined steps in the heating and cooling branches of the major hysteresis loop. 相似文献
17.
V. K. Karpasyuk G. N. Orlov G. P. Popov A. A. Shchepetkin 《Russian Physics Journal》1978,21(6):789-793
A study is made of the dependence of the coefficient of rectangularity of the hysteresis loop of ferrites of the Li-Mn-Mg and Mg-Mn-Zn system on the volume concentration of residual reverse domains. The latter is calculated from the results of measurements of the relative remanence on the basis of a model developed. It is shown that a high degree of loop rectangularity can be attained not only in the absence of reverse domains but also in the presence of a considerable volume concentration of such domains.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 109–114, June, 1978. 相似文献
18.
This study focuses on enhancing the efficiency of solid oxide fuel cells (SOFCs) by modulating the thickness of the highly resistive solid solution layer of (Ce,Zr)O2 formed between the yttria-stabilized zirconia (YSZ) electrolyte and the CeO2-based interlayer on the cathode side. The effects of the concentration of dopant in CeO2 on the thickness of the solid solution were analyzed. Yttrium-doped CeO2 (YDC) interlayers were studied, with dopant concentrations in the range of 5–40 mol%. The results revealed that the thickness of the solid solution decreased with increasing dopant concentration up to 20 mol% and then saturated at higher dopant concentrations. In addition, the electrical conductivities of yttrium-doped ceria (YDC) and the solid solution of YSZ and YDC were measured. YDC with a dopant concentration of 20 mol% exhibited the highest conductivity. The conductivities of the YSZ/YDC solid solution decreased compared to those of YDC and YSZ for each dopant concentration, and the extent of the reductions was approximately the same for all dopant concentrations. These results indicate that a dopant concentration of 20 mol% is optimal to minimize the internal resistance of SOFCs when YDC is used as the interlayer material. 相似文献
19.
给出了示波器观测铁磁材料物质磁滞回线的基本原理,针对实验中常见的错误,介绍了如何选取合理的数据并快速描绘磁滞回线的技巧。 相似文献
20.
由实验测得的磁滞回线数据的是一系列离散、带噪声的值。通过约束最小二乘方法对曲线进行分段拟合,使曲线的畸变程度得到了改善,准确地表达磁滞回线的特性,为磁材料的定量分析述提供了基础。 相似文献