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81.
We propose an efficient scheme for optimizing the optical memory of a sequence of signal light pulses in a system of ultracold atoms in Λ configuration. The memory procedure consists of write-in, storage, and retrieval phases. By applying a weak microwave field in the storage stage, additional phase-dependent terms are included, and the contrast of the output signal pulses can be dynamically controlled (enhanced or suppressed) through manipulating the relative phase φ between optical and microwave fields. Our numerical analysis shows that the contrast is enhanced to the most extent when φ=1.5π. In addition, the contrast is in proportion to the Rabi frequency of the microwave field with a certain relative phase. 相似文献
82.
工作记忆、中央执行功能与流体智力的关系分析 总被引:1,自引:0,他引:1
探讨工作记忆、中央执行功能子成分与流体智力的关系.以秦巴山区18~40岁健康成人为研究对象,通过对中央执行功能子成分、工作记忆广度以及流体智力的测量,分析了各变量之间的关系,并进一步探讨了中央执行功能各子成分的可分离性.得到 (1)工作记忆中的中央执行功能具有可分离性;(2)工作记忆广度与瑞文测验成绩之间的显著相关是刷新功能的作用;(3)相对于抑制功能和转换功能,刷新功能对流体智力具有更强的预测效应和解释力. 相似文献
83.
84.
The traditional processing technology of shape memory polymer composites is complex and the cost of high performance filler is high. Therefore, low-cost high density polyethylene (HDPE) was introduced into trans-1,4-polyisoprene (TPI) matrix as reinforcing phase, and a novel shape memory polymer was prepared by mechanical melt blending, which fully exerted the excellent properties of plastic and rubber. Because of the difference in molecular chain distribution between different blend ratios of TPI/HDPE hybrid SMPCs specimens, the change of the blend ratio of the two components affects the thermodynamic and shape memory properties of the SMPCs. A series experimental results show that the TPI/HDPE hybrid SMPCs with the blend ratio of 80/20 has excellent thermodynamic and shape memory properties. And we believe that the relevant conclusions of this study can provide valuable design reference for the development of high-performance TPI SMPCs. 相似文献
85.
Yuanhua Liu Najun Li Xuewei Xia Jianfeng Ge Qingfeng Xu Jianmei Lu 《European Polymer Journal》2011,47(5):1160-1167
Two styrene/maleimiade copolymers with pendant azobenzene chromophores, poly(styrene-1-(4-phenylazo-phenyl)-pyrrole-2,5-dione) (PS-DP) and poly((4-vinyl-benzyl)-9H-carbazole-1-(4-phenylazo-phenyl)-pyrrole-2,5-dione) (PVCz-DP), were synthesized. The polymeric memory devices based on each of the two polymer films (ITO/Polymer/Al) show similar rewritable flash memory behaviors but different transition voltages. By introduction of carbazole groups in the polymer side chains, the voltage difference from OFF to ON state of ITO/PVCz-DP/Al is reduced obviously in comparison with that of ITO/PS-DP/Al, which is beneficial to the protection of devices. Both ITO/PS-DP/Al and ITO/PVCz-DP/Al show high stability under a constant stress or continuous read pulses voltage of 1.0 V. The memory mechanism is governed by space-charge limited conduction (SCLC) on the basis of the I–V curves of these fabricated memory devices. With excellent flash memory characteristics and simple processability, the memory devices fabricated with these two styrene/maleimiade copolymers have potential applications for the future electronic memory devices. 相似文献
86.
Wei Wang Dingfeng Shen Xiao Li Dr. Yuan Yao Prof. Jiaping Lin Aurelia Wang Jiwoo Yu Prof. Zhong Lin Wang Prof. Suck Won Hong Prof. Zhiqun Lin Prof. Shaoliang Lin 《Angewandte Chemie (International ed. in English)》2018,57(8):2139-2143
Shape‐memory polymers (SMPs) are an intriguing class of smart materials possessing reversible shape change and recovery capabilities. Effective routes to shape‐memory porous films (SMPFs) are few and limited in scope owing to the difficulty in manipulating the shape change of pores by conventional methods. Herein we report an unconventional strategy for crafting light‐driven SMPFs by judiciously constructing highly ordered porous films via a facile “breath figure” approach, followed by sequential vapor crosslinking and nondestructive directional light manipulation. Micropores can thus be transformed into other shapes including rectangle, rhombus and size‐reduced micropores at room temperature. The transformed micropores can be reverted to their original shapes by either thermal annealing or UV irradiation. As such, this strategy expands the rich diversity of SMPs accessible. 相似文献
87.
《先进技术聚合物》2018,29(8):2336-2343
Morphology structure and interfacial interaction are crucial factors for shape memory thermoplastic vulcanizates. In this study, shape memory thermoplastic vulcanizates based on poly(lactic acid) (PLA) and nitrile butadiene rubber (NBR) were prepared through dynamic vulcanization. The influence of acrylonitrile (ACN) content on the morphology, compatibility, shape memory property, and mechanical property was investigated. A co‐continuous structure was observed. The interfacial compatibilization between PLA and NBR phases occurred, resulting in a significantly improved interface adhesion and interfacial interaction, which was confirmed by Fourier transform infrared spectroscopy. With such a novel structure, the PLA/NBR TPVs owned an excellent shape memory property and further improved with increasing ACN content of NBR, which could be explained that the cross‐linked continuous NBR phase provided a stronger recovery driving force. In the meantime, tensile strength and elongation at break of TPVs increased with increase in ACN content. It is concluded that the preparation of dynamically vulcanized thermoplastic vulcanizate with co‐continuous structure and strong interfacial adhesion is beneficial to obtain outstanding shape memory effect. 相似文献
88.
Tripti Vimal Shivani Pandey Swadesh K. Gupta Dharmendra P. Singh Kaushlendra Agrahari Govind Pathak 《Liquid crystals》2018,45(5):687-697
Rod-shaped 5 wt.% copper-doped ZnO (ZnO:Cu2+) ferromagnetic nanoparticles (NPs), prepared by hydrothermal method, were dispersed in ferroelectric liquid crystal (FLC) named Felix 17/100. The effect of ferromagnetic NPs on the physical properties of FLC material (Felix 17/100) has been investigated by dielectric, electro-optical and polarising optical microscopic methods. A noteworthy time-dependent memory has been observed in the NPs-dispersed FLC composite attributed to the coupling of magnetic field associated to NPs with the director orientation of FLC. Improvement in spontaneous polarisation and dielectric susceptibility of FLC material has been ensued with the addition of ferromagnetic NPs. Faster electro-optic response, at lower applied voltage, has also been observed in NPs-dispersed FLC composite. These changes are accredited to the magneto-electric dipolar coupling existing due to the interactions between magnetic-dipole and electric-dipole moments of magnetic NPs and FLC material, respectively. The formation of periodic domains capable to show memory effect has been observed in composite. The observed time-dependent memory was confirmed by dielectric and electro-optical methods. FLC material enriched with the properties of ferromagnetic NPs can be utilised in advanced multifunctional optical devices, time-dependent memory-based security devices and computational purposes. 相似文献
89.
Partially substituting Sb for In, we found an irreversible transformation of martensite to intermartensite at 90 K in Ni50Mn34In12Sb4 alloy during heating. The reverse transformation of martensite and intermartensite to the parent phase induced by a magnetic field has been investigated. The results indicate that, if a sufficiently high magnetic field is applied, the intermartensite state is no longer necessary as an intermediate state. Thus, a difference of the transformation originating from magnetic and from thermal energies has been found. In this competition, lattice distortions play an important role to promote the occurrence of the intermediate intermartensitic path. 相似文献
90.
A. Amari A. Walther M. Huang M. Afzelius B. Lauritzen H. de Riedmatten 《Journal of luminescence》2010,130(9):1579-1585
We present an efficient photon-echo experiment based on atomic frequency combs [Phys. Rev. A 79 (2009) 052329]. Echoes containing an energy of up to 35% of that of the input pulse are observed in a Pr3+-doped Y2SiO5 crystal. This material allows for the precise spectral holeburning needed to make a sharp and highly absorbing comb structure. We compare our results with a simple theoretical model with satisfactory agreement. Our results show that atomic frequency combs has the potential for high-efficiency storage of single photons as required in future long-distance communication based on quantum repeaters. 相似文献