分类： 核科学技术 >> 辐射物理与技术 提交时间： 2025-01-01
摘要： Grating-based X-ray phase-contrast imaging enhances the contrast of imaged objects, particularly soft tissues. However, the radiation dose in computed tomography (CT) is generally excessive owing to the complex collection scheme. Sparse-view CT collection reduces the radiation dose, but with reduced resolution and reconstructed artifacts particularly in analytical reconstruction methods. Recently, deep learning has been employed in sparse-view CT reconstruction and achieved state-of-the-art results. Nevertheless, its low generalization performance and requirement for abundant training datasets have hindered the practical application of deep learning in phase-contrast CT. In this study, a CT model was used to generate a substantial number of simulated training datasets, thereby circumventing the need for experimental datasets. By training a network with simulated training datasets, the proposed method achieves high generalization performance in attenuation-based CT and phase-contrast CT, despite the lack of sufficient experimental datasets. In experiments utilizing only half of the CT data, our proposed method obtained an image quality comparable to that of the filtered back-projection algorithm with full-view projection. The proposed method simultaneously addresses two challenges in phase-contrast three-dimensional imaging, namely, the lack of experimental datasets and the high exposure dose, through model-driven deep learning. This method significantly accelerates the practical application of phase-contrast CT.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-08
Zhang, WB [Zhang, Wenbin][ 1,2 ]
Wang, C [Wang, Cheng][ 3 ]
Liu, G [Liu, Gang][ 1 ]
Wang, J [Wang, Jun][ 2 ]
Chen, Y [Chen, Yu][ 3 ]
Li, RW [Li, Run-Wei][ 1 ]
摘要： Linear and hyperbranched poly(azomethine)s (PAMs)-based on tri- phenylamine moieties are synthesized and used as the functioning layers in the Ta/PAM/Pt resistive switching memory devices. Com- parably, the hyperbranched PAM with isotropic architecture and semi-crystalline nature shows enhanced memory behaviors with more uniform distribution of the HRS and LRS resistances.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Pan, L [Pan, Liang][ 1,2 ]
Ji, ZH [Ji, Zhenghui][ 1,2 ]
Yi, XH [Yi, Xiaohui][ 1,2 ]
Zhu, XJ [Zhu, Xiaojian][ 1,2 ]
Chen, XX [Chen, Xinxin][ 1,2 ]
Shang, J [Shang, Jie][ 1,2 ]
Liu, G [Liu, Gang][ 1,2 ]
Li, RW [Li, Run-Wei][ 1,2 ]
摘要： Metal-organic frameworks (MOFs), which are formed by association of metal cations or clusters of cations (“nodes”) with soft organic bridging ligands (“linkers”), are a fascinating class of flexible crystalline hybrid materials offering potential strategy for the construction of flexible electronics. In this study, a high-quality MOF nanofilm, HKUST-1, on flexible gold-coated polyethylene terephthalate substrates is fabricated using liquid phase epitaxy approach. Uniform and reproducible resistive switching effect, which can be sustained under the strain of as high as 2.8%, and over the wide temperature range of –70 to +70 °C, is observed for the first time in the all solid-state Au/ HKUST-1/Au/ thin film structures. Through conductive atomic force micro- scopic and depth-profiling X-ray photoelectron spectroscopicanalysis, it is proposed that the electric field-induced migration of the Cu2+ ions, which may lead to subsequent pyrolysis of the trimesic acid linkers and thus the formation of highly conducting filaments, could be the possible origin for the observed uniform resistance switching in HKUST-1 nanofilms.
提交时间： 2017-05-02
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Zhang, CC [Zhang, Chaochao][ 1,2,3 ]
Tai, YT [Tai, Yu-Tsung][ 4 ]
Shang, J [Shang, Jie][ 1,2 ]
Liu, G [Liu, Gang][ 1,2 ]
Wang, KL [Wang, Kun-Li][ 4 ]
Hsu, CW [Hsu, Chienwen][ 4 ]
Yi, XH [Yi, Xiaohui][ 1,2 ]
Yang, X [Yang, Xi][ 1,2 ]
Xue, WH [Xue, Wuhong][ 1,2 ]
Tan, HW [Tan, Hongwei][ 1,2
摘要： In this study, an artificial synapse with a sandwich structure of Ta/ethyl viologen diperchlorate [EV(ClO4)2]/triphenylamine-based polyimide (TPA-PI)/Pt is fabricated directly on a flexible PET substrate and exhibits distinctive history-dependent memristive behaviour, which meets the basic requirements for synapse emulation. Essential synaptic plasticity (including long-term plasticity and short-term plasticity) and some memory and learning behaviours of human beings (including the conversion from short-term memory to long-term memory and the ‘‘learning–forgetting–relearning’’) have been demonstrated in our device. More importantly, the device still exhibits the synaptic performance when the surface strain of the device reaches 0.64% (or, the bending radius reaches 10 mm). Moreover, the device was able to endure 100 bending cycles. Our findings strongly demonstrate that the organic artificial synapse is not only promising for constructing a neuromorphic information storage and processing system, but is also interesting for the realization of wearable neuromorphic computing systems
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Yi, XH [Yi, Xiaohui][ 1,2 ]
Shang, J [Shang, Jie][ 1,2 ]
Pan, L [Pan, Liang][ 1,2 ]
Tan, HW [Tan, Hongwei][ 1,2 ]
Chen, B [Chen, Bin][ 1,2 ]
Liu, G [Liu, Gang][ 1,2 ]
Huang, G [Huang, Gang][ 3 ]
Bernot, K [Bernot, Kevin][ 3 ]
Guillou, O [Guillou, Olivier][ 3 ]
Li, RW [Li, Run-Wei][ 1,2 ]i
摘要： Switching luminescence of lanthanide-based molecules through an external electric field is considered as a promising approach toward novel functional molecule-based devices. Classic routes use casted films and liquid electrolyte as media for redox reactions. Such protocol, even if efficient, is relatively hard to turn into an effective solid-state device. In this work, we explicitly synthesize lanthanide-based dimers whose luminescent behavior is affected by the presence of Cu2+ ions. Excellent evaporability of the dimers and utilization of Cu2+- based solid-state electrolyte makes it possible to reproduce solution behavior at the solid state. Reversible modulation of Cu2+ ions transport can be achieved by an electric field in a solid-state device, where lanthanide-related luminescence is driven by an electric field. These findings provide a proof-of-concept alternative approach for electrically driven modulation of solid-state luminescence and show promising potential for information storage media in the future.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Zhang, WB [Zhang, Wenbin][ 1,2,3 ]
Wang, C [Wang, Cheng][ 4 ]
Liu, G [Liu, Gang][ 1,3 ]
Zhu, XJ [Zhu, Xiaojian][ 1,3 ]
Chen, XX [Chen, Xinxin][ 1,3 ]
Pan, L [Pan, Liang][ 1,3 ]
Tan, HW [Tan, Hongwei][ 1,3 ]
Xue, WH [Xue, Wuhong][ 1,3 ]
Ji, ZH [Ji, Zhenghui][ 1,3 ]
Wang, J [Wang, Jun][ 2 ]
Chen, Y [Chen, Yu][ 4 ]
Li, RW [Li, Run-Wei][ 1,3 ]
摘要： Thermally stable poly(triphenylamine) (PTPA) synthesized by an oxidative coupling reaction is used as the functional layer in memory devices, which exhibit non-volatile bistable resistive switching behavior with a large ON/OFF ratio over 5 108, a long retention time exceeding 8 103 s and a wide working temperature range of 30–390 K.
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