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14,556 results on '"GAO Lei"'

151. Buckyball-metal complexes as promising carriers of astronomical unidentified infrared emission bands

Author

Hou, Gao-Lei, Lushchikova, Olga V., Bakker, Joost M., Lievens, Peter, Decin, Leen, and Janssens, Ewald

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Atomic and Molecular Clusters, Physics - Chemical Physics
Abstract

Infrared emission bands with wavelengths between 3-20 {\mu}m are observed in a variety of astrophysical environments [1,2]. They were discovered in the 1970s and are generally attributed to organic compounds [3,4]. However, over 40 years of research efforts still leave the source of these emission bands largely unidentified [5-7]. Here, we report the first laboratory infrared (6-25 {\mu}m) spectra of gas-phase fullerene-metal complexes, [C60-Metal]+ (Metal = Fe and V), and show with density functional theory calculations that complexes of C60 with cosmically abundant metals, including Li, Na, K, Mg, Ca, Al, V, and Fe, all have similar infrared spectral patterns. Comparison with observational infrared spectra from several fullerene-rich planetary nebulae demonstrates a strong positive linear cross-correlation. The infrared features of [C60-Metal]+ coincide with four bands attributed earlier to neutral C60 bands, and in addition also with several to date unexplained bands. Abundance and collision theory estimates furthermore indicate that [C60-Metal]+ could plausibly form and survive in astrophysical environments. Hence, [C60-Metal]+ are proposed as promising carriers, in supplement to C60, of astronomical infrared emission bands, potentially representing the largest molecular species in space other than the bare fullerenes C60, C60+, and C70. This work opens a new chapter for studying cosmic fullerene species and carbon chemistry in the Universe., Comment: 45 pages (23 pages for main text and 22 pages for supplementary information) 21 figures (10 figures for main text and 11 figures for supplementary information) 6 tables (1 tables for main text and 5 tables for supplementary information)

Published
2022
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152. Wafer-scale epitaxial growth of the thickness-controllable van der Waals ferromagnet CrTe2 for reliable magnetic memory applications

Author

Liu, Xinqi, Xia, Yunyouyou, Gao, Lei, Huang, Puyang, Liao, Liyang, Cui, Baoshan, Backes, Dirk, van der Laan, Gerrit, Hesjedal, Thorsten, Ji, Yuchen, Chen, Peng, Wu, Fan, Wang, Meixiao, Zhang, Junwei, Yu, Guoqiang, Song, Cheng, Chen, Yulin, Liu, Zhongkai, Yang, Yumeng, Peng, Yong, Li, Gang, Yao, Qi, and Kou, Xufeng

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

To harness the intriguing properties of two-dimensional van der Waals (vdW) ferromagnets (FMs) for versatile applications, the key challenge lies in the reliable material synthesis for scalable device production. Here, we demonstrate the epitaxial growth of single-crystalline 1T-CrTe2 thin films on 2-inch sapphire substrates. Benefiting from the uniform surface energy of the dangling bond-free Al2O3(0001) surface, the layer-by-layer vdW growth mode is observed right from the initial growth stage, which warrants precise control of the sample thickness and atomically smooth surface morphology across the entire wafer. Moreover, the presence of the Coulomb interaction at the CrTe2/Al2O3 interface serves as an effective tuning parameter to tailor the anomalous Hall response, and the structural optimization of the CrTe2-based spin-orbit torque device leads to a substantial switching power reduction by 54%. Our results may lay out a general framework for the design of energy-efficient spintronics based on configurable vdW FMs., Comment: 20 pages, 4 figures

Published
2022
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153. Intrinsic Spectrum Analysis of Laser Dynamics Based on Fractional Fourier Transform

Author

Huang, Ligang, Lan, Tianyi, Zhang, Chaoze, Dang, Laiyang, Guan, Tianyu, Zheng, Bowen, Liu, Shunli, Gao, Lei, Huang, Wei, Yin, Guolu, and Zhu, Tao

Subjects
Physics - Optics
Abstract

Intrinsic spectrum that results from the coupling of spontaneous emission in a laser cavity, can determine the energy concentration and coherence of lasers, which is crucial for the optical high-precision measurement. Up to now, it is hard to analyze the intrinsic spectrum in the high-speed laser dynamics process, especially under the condition of fast wavelength sweeping. In this work, a new method to analyze the laser intrinsic spectrum is proposed with the laser energy decomposition to a series of chirp-frequency signals, which is realized by fractional Fourier transform (FRFT) of the coherently reconstructed laser waveform. The new understanding of the energy distribution of lasers contributes to the accurate characterization of laser dynamical parameters in time-frequency domain. In the proof-of-concept experiment, the time-frequency dynamical process of a commercial wavelength swept laser is tested with different wavelength-scanning speeds, and the most suitable measurement time window width required for the FRFT-based narrowest spectrum is also explored. The proposed analysis method of laser dynamical parameters will promote the understanding of laser dynamics, and benefit for the optical precision measurement applications.

Published
2022
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154. Daytime napping and Alzheimers dementia: A potential bidirectional relationship.

Author

Li, Peng, Gao, Lei, Yu, Lei, Zheng, Xi, Ulsa, Ma, Yang, Hui-Wen, Gaba, Arlen, Bennett, David, Buchman, Aron, Hu, Kun, Leng, Yue, and Yaffe, Kristine

Subjects
actigraphy, aging, cognitive aging, cohort study, longitudinal association, sleep, Humans, Aged, Alzheimer Disease, Sleep, Aging, Cognition, Actigraphy
Abstract

INTRODUCTION: Daytime napping is frequently seen in older adults. The longitudinal relationship between daytime napping and cognitive aging is unknown. METHODS: Using data from 1401 participants of the Rush Memory and Aging Project, we examined the longitudinal change of daytime napping inferred objectively by actigraphy, and the association with incident Alzheimers dementia during up to 14-year follow-up. RESULTS: Older adults tended to nap longer and more frequently with aging, while the progression of Alzheimers dementia accelerates this change by more than doubling the annual increases in nap duration/frequency. Longer and more frequent daytime naps were associated with higher risk of Alzheimers dementia. Interestingly, more excessive (longer or more frequent) daytime napping was correlated with worse cognition a year later, and conversely, worse cognition was correlated with more excessive naps a year later. DISCUSSION: Excessive daytime napping and Alzheimers dementia may possess a bidirectional relationship or share common pathophysiological mechanisms.

Published
2023

161. Contributors

Author

Bagaev, A., primary, Bagaeva, M., additional, Bao, Lian-Jun, additional, Beaurepaire, Max, additional, Bessa, Filipa, additional, Bordignon, Frederique, additional, Bouzid, Nadia, additional, Ceia, Filipe R., additional, Chen, Qiqing, additional, Chubarenko, I., additional, de Lima, Juliana Aristéia, additional, Dris, Rachid, additional, Esiukova, E., additional, Feng, Huan, additional, Fetisov, S., additional, Fu, Dongdong, additional, Gao, Lei, additional, Gasperi, Johnny, additional, Gondikas, Andreas, additional, Hale, Robert C., additional, Hansson, Lars-Anders, additional, Harmon, S. Michele, additional, He, Hui, additional, Hong, Sang Hee, additional, Isachenko, I., additional, Jang, Mi, additional, Ji, Mengru, additional, Ji, Rong, additional, Jocic, Simonne, additional, Khatmullina, L., additional, King, Ashley E., additional, Leung, Ho Man, additional, Li, Daoji, additional, Li, Shibo, additional, Li, Wai Chin, additional, Liao, Zhianqi, additional, Liu, Ruijuan, additional, Ma, Cuizhu, additional, Mai, Lei, additional, Mattsson, Karin, additional, Nguyen, Minh Trang, additional, Ou, Huase, additional, Peng, Lin, additional, Ramirez, Julianna M., additional, Sha, Xiaoyu, additional, Shi, Huahong, additional, Shim, Won Joon, additional, Stratmann, Cleo, additional, Sun, Xiang-Fei, additional, Tassin, Bruno, additional, Wang, Fei, additional, Wang, Fen, additional, Wang, Lei, additional, Wang, Yuan, additional, Wong, Charles S., additional, Xue, Yining, additional, Yan, Xiaoyun, additional, Zeng, Eddy Y., additional, Zhang, Junjie, additional, Zhao, Shiye, additional, Zhu, Lixin, additional, and Zobkov, M., additional

Published
2024
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162. More Socio-Emotional Regulation, More Effective? Exploring Social Regulation of Learning in Collaborative Argumentation among the High and Low Performing Groups

Author

Li, Xiaoran, Li, Yanyan, Hu, Wanqing, Li, Keru, and Gao, Lei

Abstract

Collaborative argumentation (CA) is a prolific but challenging form of collaborative learning that requires group members to engage in a quantity of regulation to sustain the group's productive functioning. The purpose of this study was to investigate the differences between the high- and low-performing CA groups in terms of (a) challenges and triggered social regulation during CA, and (b) sequential patterns of social regulation used by those groups. From that, this research aimed to reveal what may promote or constrain CA from the perspective of social regulation. The target groups were selected from a larger sample of 14 groups based on the groups' argument diagram scores after they participated in a 90-min CA activity. Videos and interview data were collected and analyzed to reveal the encountered challenges and social regulation in the activity. Several findings were obtained. First, the low-performing groups encountered far more challenges and the biggest difference between the high- and low-performing groups was the socio-emotional challenges. Second, more challenges were regulated in low-performing groups, with more cognitive and socio-emotional challenges being regulated and less motivational challenges being handled. For cognitive challenges, the effective strategies to deal with the deadlock in reaching an agreement were identified among high-performing groups. For socio-emotional challenges, although more have been regulated in low-performing groups, the tense atmosphere made social regulation less successful. For motivational challenges, low-performing groups paid little attention to other members' participation. Third, the high- and low-performing groups demonstrated different sequential patterns, such as more transitions related to socio-emotional regulation and evaluation in high-performing groups. Pedagogical implications and the need to support students to cope with socio-emotional challenges are discussed in the last.

Published
2023
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163. Vision Transformer with Convolutions Architecture Search

Author

Zhang, Haichao, Hao, Kuangrong, Pedrycz, Witold, Gao, Lei, Tang, Xuesong, and Wei, Bing

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

Transformers exhibit great advantages in handling computer vision tasks. They model image classification tasks by utilizing a multi-head attention mechanism to process a series of patches consisting of split images. However, for complex tasks, Transformer in computer vision not only requires inheriting a bit of dynamic attention and global context, but also needs to introduce features concerning noise reduction, shifting, and scaling invariance of objects. Therefore, here we take a step forward to study the structural characteristics of Transformer and convolution and propose an architecture search method-Vision Transformer with Convolutions Architecture Search (VTCAS). The high-performance backbone network searched by VTCAS introduces the desirable features of convolutional neural networks into the Transformer architecture while maintaining the benefits of the multi-head attention mechanism. The searched block-based backbone network can extract feature maps at different scales. These features are compatible with a wider range of visual tasks, such as image classification (32 M parameters, 82.0% Top-1 accuracy on ImageNet-1K) and object detection (50.4% mAP on COCO2017). The proposed topology based on the multi-head attention mechanism and CNN adaptively associates relational features of pixels with multi-scale features of objects. It enhances the robustness of the neural network for object recognition, especially in the low illumination indoor scene.

Published
2022

193. Status of aquatic organisms resources and their environments in Yangtze River system (2017–2021)

Author

Yang, Haile, Shen, Li, He, Yongfeng, Tian, Huiwu, Gao, Lei, Wu, Jinming, Mei, Zhigang, Wei, Nian, Wang, Lin, Zhu, Tingbing, Hu, Feifei, Gong, Jinling, Du, Hongchun, Duan, Xinbin, Deng, Huatang, Wang, Daoqun, Zhu, Fengyue, Li, Yunfeng, Wu, Fan, Ru, Huijun, Zhang, Yan, Li, Junyi, Yang, Junlin, Zhou, Yuntao, Fang, Dongdong, Wang, Yinping, Lin, Danqing, Yang, Yanping, Li, Peijie, Liu, Silei, Yang, Jian, Zhuang, Ping, Wang, Sikai, Zhang, Tao, Yang, Gang, Yang, Wenbo, Yuan, Lilai, Cao, Kun, Xu, Shuo, Liu, Huiyuan, Liang, Zhiqiang, Wang, Chongrui, Li, Hong, Yuan, Xiping, Yang, Xin, Fu, Yilong, Zhang, Yanping, Zhang, Haixin, Tao, Zhiying, Wang, Sheng, Gao, Xiaoping, Jin, Binsong, Li, Kemao, Wang, Guojie, Jian, Shenglong, Li, Yingqin, Xue, Chenjiang, Lei, Chunyun, Xue, Shaowei, Sun, Yi, Zhu, Bin, Shao, Ke, Hu, Xingkun, Xiong, Meihua, Du, Jun, He, Bin, Yan, Tao, Huang, Yingying, Zou, Yuanchao, Xie, Biwen, Wang, Yongming, Li, Bin, Liu, Fei, Zhang, Yaoyao, Fan, Fei, Wang, Zhijian, Huang, Jing, Gu, Haoran, Ge, Hailong, Dan, Yan, Li, Yan, Wang, Shuqiao, Zhang, Chuang, Zhou, Lu, Wang, Xue, Zeng, Sheng, Xiang, Yan, He, Xugang, Qin, Jianhui, Xia, Chengxing, Hou, Jie, Shi, Yifu, Gao, Lifang, Zhu, Zhiqiang, Shen, Hongbao, Du, Yun, Duan, Xuejun, Xiong, Jiawu, Yang, Deguo, Liu, Shaoping, Ni, Zhaohui, Zhang, Hui, Liu, Kai, Zhao, Feng, Li, Yingren, Wang, Jianwei, and Wei, Qiwei

Published
2024
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