检索结果-南通市图书馆

The Emergence of Functional Ultrasound for Noninvasive Brain-Computer Interface

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

research 2024年第2期6卷 301-317页

作者： Hairong Zheng Lili Niu Weibao Qiu Dong Liang Xiaojing Long Guanglin Li Zhiyuan Liu Long Meng institute of Biomedical and health Engineering Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen518055China Shenzhen institute of advanced Integration Technology Chinese Academy of Sciences and The Chinese University of Hong KongShenzhen518055China

A noninvasive brain-computer interface is a central task in the comprehensive analysis and understanding of the brain and is an important challenge in international brain-science *** implanted brain-computer interfaces are cranial and invasive,which considerably limits their *** development of new noninvasive reading and writing technologies will advance substantial innovations and breakthroughs in the field of brain-computer ***,we review the theory and development of the ultrasound brain functional imaging and its ***,we introduce latest advancements in ultrasound brain modulation and its applications in rodents,primates,and human;its mechanism and closed-loop ultrasound neuromodulation based on electroencephalograph are also ***,high-frequency acoustic noninvasive brain-computer interface is prospected based on ultrasound super-resolution imaging and acoustic tweezers.

关键词： breakthrough computer Computer

Perspective for OER electrocatalysts:Lattice engineering of clay-like frameworks with near-surface cluster active sites

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological sciences) 2024年第1期67卷 330-334页

作者： ZHANG DanTong QIAN BinBin XUE DongFeng Multiscale Crystal Materials research Center Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Near-surface cluster active centers(NSCAC)are pivotal functional units in the catalysis of oxygen evolution reaction(OER),which exceeds the limitations imposed by the diverse coordination environments experienced in atomic and molecular active centers,thereby serving as an exceptional medium for exploring the dynamic catalytic processes of metal active sites[1,2].In the OER,the NSCAC primarily consist of the catalytic site and the first neighboring coordinating *** investigation of NSCAC surpasses the exclusive reliance on the electron state regulation mechanism at the atomic level.

关键词： cluster centers exceptional

维普期刊数据库

Two-stage aging treatment to accelerate aging kinetics without impairing strength in B4C/7A04Al composite

在线全文

学校读者我要写书评

暂无评论

Science China Technological sciences 2024年第8期67卷 2485-2492页

作者： CHEN YunTao MA GuoNan ZHU ShiZe WANG Dong XIAO BoLv MA ZongYi Shi-Changxu Innovation Center for advanced Materials Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China Centre of Excellence for advanced Materials

Aging treatments are the key process to obtain satisfactory strength for 7xxxAl alloys and their composites. However, traditional single-stage（SS） aging is time-consuming to reach a peak strength condition. In this study, an efficient 120℃ + 160℃ two-stage（ts） aging treatment was proposed on a B4C/7A04Al composite fabricated via powder metallurgy（PM） technology, which could acquire similar peak-aging strength but only took about 15% of the time compared to traditional 120℃ SS aging. The evolution of precipitation during the ts aging was investigated, as well as those of the 7A04Al alloys for comparison. In the second stage aging process, the higher aging temperature accelerated the nucleation of η′ phases inside the grains and thus increased the density of precipitates. Moreover, the short aging time limited the coarsening of precipitates and the broadening of precipitatefree zones. The above factors were beneficial for quickly obtaining satisfactory precipitation strengthening effects. The B4C/7A04Al composite exhibited slower aging kinetics than the 7A04Al alloy in the ts aging. Mg elements consumption by the chemical reaction between B impurities introduced by B4C particles and the Al matrix was considered to potentially retard the aging kinetics of the B4C/7A04Al composite. Nevertheless, the precipitation sequence was not affected.

关键词： aluminum matrix composites aging treatment powder metallurgy mechanical properties precipitation

A Secure Cryptographic System Based on Steady-State Visual Evoked Potential Brain-Computer Interface Technology

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science and Information 2024年第3期12卷 423-432页

作者： Xu XIAO Feiyang ZHANG Wenhan YIN Dezhi ZHENG College of Life and Environmental Science Minzu University of China School of Instrumentation and Optoelectronic Engineering Beihang University advanced research institute of Multidisciplinary sciences Beijing Institute of Technology

Addressing the vulnerability of contact-based keyboard password systems to disclosure,this paper proposes and validates the feasibility of a non-contact secure password system based on brain-computer interface(BCI) technology that detects steady-state visual evoked potential(SSVEP)signals. The system first lets a testee look at a digital stimulus source flashing at a specific frequency,and uses a wearable dry electrode sensor to collect the SSVEP signal. Secondly, a canonical correlation analysis method is applied to analyze the frequency of the stimulus source that the testee is looking at, and feeds back a code result through headphones. Finally, after all password codes are input, the system makes a judgment and provides visual feedback to the testee. Experiments were conducted to test the accuracy of the system, where twelve stimulus target frequencies between 10-16Hz were selected within the easily recognizable flicker frequency range of human brain, and each of them was tested for 12 times. The results demonstrate that this SSVEP-BCI-based system is feasible, achieving an average accuracy rate of 97.2%, and exhibits promising applications in various domains such as financial transactions and identity recognition.

关键词： brain computer interface steady-state visual evoked potential password system

Temporally consistent video colorization with deep feature propagation and self-regularization learning

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Computational Visual Media 2024年第2期10卷 375-395页

作者： Yihao Liu Hengyuan Zhao Kelvin CKChan Xintao Wang Chen Change Loy Yu Qiao Chao Dong Shenzhen institute of advanced Technology Chinese Academy of SciencesShenzhen 518055China University of Chinese Academy of sciences Beijing 100049China Department of Electrical&Computer Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798 Applied research Center Tencent PCGShenzhenChina

Video colorization is a challenging and highly ill-posed *** recent years have witnessed remarkable progress in single image colorization,there is relatively less research effort on video colorization,and existing methods always suffer from severe flickering artifacts(temporal inconsistency)or unsatisfactory *** address this problem from a new perspective,by jointly considering colorization and temporal consistency in a unified ***,we propose a novel temporally consistent video colorization(TCVC)*** effectively propagates frame-level deep features in a bidirectional way to enhance the temporal consistency of ***,TCVC introduces a self-regularization learning(SRL)scheme to minimize the differences in predictions obtained using different time *** does not require any ground-truth color videos for training and can further improve temporal *** demonstrate that our method can not only provide visually pleasing colorized video,but also with clearly better temporal consistency than state-of-the-art methods.A video demo is provided at https://***/watch?v=c7dczMs-olE,while code is available at https://***/lyh-18/TCVC-Tem porally-Consistent-Video-Colorization.

关键词： video colorization temporal consistency feature propagation self-regularization

A comparison of statistical learning of naturalistic textures between DCNNs and the human visual hierarchy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Technological sciences 2024年第8期67卷 2310-2318页

作者： LU XinCheng YUAN ZiQi ZHANG YiChi AI HaiLin CHENG SiYuan GE YiRan FANG Fang CHEN NiHong Department of Psychological and Cognitive sciences Tsinghua University Department of Computer Science and Technology Tsinghua University School of Psychological and Cognitive sciences and Beijing Key Laboratory of Behavior and Mental health Peking University Key Laboratory of Machine Perception (Ministry of Education) Peking University Peking-tsinghua Center for Life sciences Peking University IDG/McGovern institute for Brain research Peking University State Key Laboratory of Brain and Cognitive Science Institute of Psychology Chinese Academy of Sciences IDG/McGovern institute for Brain research Tsinghua University

The visual system continuously adapts to the statistical properties of the environment. Existing evidence shows a close resemblance between deep convolutional neural networks(CNNs) and primate visual stream in neural selectivity to naturalistic textures above the primary visual processing stage. This study delves into the mechanisms of perceptual learning in CNNs,focusing on how they assimilate the high-order statistics of natural textures. Our results show that a CNN model achieves a similar performance improvement as humans, as manifested in the learning pattern across different types of high-order image statistics. While L2 was the first stage exhibiting texture selectivity, we found that stages beyond L2 were critically involved in learning. The significant contribution of L4 to learning was manifested both in the modulations of texture-selective responses and in the consequences of training with frozen connection weights. Our findings highlight learning-dependent plasticity in the mid-to-high-level areas of the visual hierarchy. This research introduces an AI-inspired approach for studying learning-induced cortical plasticity, utilizing DCNNs as an experimental framework to formulate testable predictions for empirical brain studies.

关键词： CNN perceptual learning naturalistic texture psychophysics

Optimization of Random Feature Method in the High-Precision Regime

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2024年第2期6卷 1490-1517页

作者： Jingrun Chen Weinan E Yifei Sun School of Mathematical sciences and Suzhou institute for advanced research Suzhou 215006JiangsuChina University of Science and Technology of China Hefei 230026AnhuiChina Center for Machine Learning research and School of Mathematical sciences Peking UniversityBeijing 100871China AI for Science institute Beijing 100084China School of Mathematical sciences Soochow UniversitySuzhou 215006JiangsuChina

Machine learning has been widely used for solving partial differential equations(PDEs)in recent years,among which the random feature method(RFM)exhibits spectral accuracy and can compete with traditional solvers in terms of both accuracy and ***,the optimization problem in the RFM is more difficult to solve than those that arise in traditional *** the broader machine-learning research,which frequently targets tasks within the low-precision regime,our study focuses on the high-precision regime crucial for solving *** this work,we study this problem from the following aspects:(i)we analyze the coeffcient matrix that arises in the RFM by studying the distribution of singular values;(ii)we investigate whether the continuous training causes the overfitting issue;(ii)we test direct and iterative methods as well as randomized methods for solving the optimization *** on these results,we find that direct methods are superior to other methods if memory is not an issue,while iterative methods typically have low accuracy and can be improved by preconditioning to some extent.

关键词： Random feature method(RFM) Partial differential equation(PDE) Least-squares problem Direct method Iterative method

Will the 2022 compound heatwaveedrought extreme over the Yangtze River Basin become Grey Rhino in the future?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Climate Change research 2024年第3期15卷 547-556页

作者： Ai-Qing FENG Qing-Chen CHAO Lu-Lu LIU Ge GAO Guo-Fu WANG Xue-Jun ZHANG Qi-Guang WANG China Meteorological Administration Key Laboratory for Climate Prediction Studies National Climate CentreBeijing 100081China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China China institute of Water Resources and Hydropower research Beijing 100038China China Meteorological Administration training Centre China Meteorological AdministrationBeijing 100081China

The increasingly frequent and severe regional-scale compound heatwave-drought extreme events(CHDEs),driven by global warming,present formidable challenges to ecosystems,residential livelihoods,and economic ***,uncertainty persists regarding the future trend of CHDEs and their insights into regional spatiotemporal *** integrating daily meteorological data from observations in 1961-2022 and global climate models(GCMs)based on the Shared Socioeconomic Pathways,the evolution patterns of CHDEs were compared and examined among three sub-catchments of the Yangtze River Basin,and the return periods of CHDE in 2050s and 210Os were *** findings indicate that the climate during the 2022 CHDE period was the warmest and driest recorded in 1961-2022,with precipitation less than 154.5 mm and a mean daily maximum temperature 3.4°C higher than the average of 1981-2010,whereas the char-acteristics in the sub-catchments exhibited temporal and spatial *** July-August 2022,the most notable feature of CHDE was its extremeness since 1961,with return periods of~200-year in upstream,80-year in midstream,and 40-year in downstream,*** 2050,the return periods witnessed 2022 CHDE would likely be reduced by *** towards 2100,under the highest emission scenario of SSP585,it was projected to substantially increase the frequency of CHDEs,with return periods reduced to one-third in the upstream and downstream,as well as halved in the *** findings provide valuable insights into the changing risks associated with forthcoming climate extremes,emphasizing the urgency of addressing these challenges in regional management and sustainable development.

关键词： Compound extreme event Joint return period Drought Heatwave Climate change Yangtze River Basin

Two-stage aging treatment to accelerate aging kinetics without impairing strength in BC/7A04Al composite

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Technological sciences 2024年

作者： CHEN YunTao MA GuoNan ZHU ShiZe WANG Dong XIAO BoLü MA ZongYi Shi-Changxu Innovation Center for advanced Materials Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China Centre of Excellence for advanced Materials

Aging treatments are the key process to obtain satisfactory strength for 7xxxAl alloys and their composites. However, traditional single-stage （SS） aging is time-consuming to reach a peak strength condition. In this study, an efficient 120℃+160℃ two-stage（ts） aging treatment was proposed on a B4C/7A04Al composite fabricated via powder metallurgy （PM） technology, which could acquire similar peak-aging strength but only took about 15%of the time compared to traditional 120℃ SS aging. The evolution of precipitation during the ts aging was investigated, as well as those of the 7A04Al alloys for comparison. In the second stage aging process, the higher aging temperature accelerated the nucleation of η′phases inside the grains and thus increased the density of precipitates. Moreover, the short aging time limited the coarsening of precipitates and the broadening of precipitatefree zones. The above factors were beneficial for quickly obtaining satisfactory precipitation strengthening effects. The B4C/7A04Al composite exhibited slower aging kinetics than the 7A04Al alloy in the ts aging. Mg elements consumption by the chemical reaction between B impurities introduced by B4C particles and the Al matrix was considered to potentially retard the aging kinetics of the B4C/7A04Al composite. Nevertheless, the precipitation sequence was not affected.

关键词：