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Dynamic imaging through scattering medium under white-light illumination [Invited]

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Chinese Optics Letters 2024年第6期22卷 46-51页

作者： Junyao Lei Hui Chen Yuan Yuan Yunong Sun Jianbin Liu Huaibin Zheng Yuchen He Electronic Material Research laboratory Key Laboratory of the Ministry of Education and International Centre for Dielectric ResearchXi’an Jiaotong UniversityXi’an 710049China

Imaging objects hidden behind turbid media is of great scientific importance and practical value, which has been drawing a lot of attention recently. However, most of the scattering imaging methods rely on a narrow linewidth of light, limiting their application. A mixture of the scattering light from various spectra blurs the detected speckle pattern, bringing difficulty in phase retrieval. Image reconstruction becomes much worse for dynamic objects due to short exposure times. We here investigate non-invasively recovering images of dynamic objects under white-light irradiation with the multi-frame OTF retrieval engine (MORE). By exploiting redundant information from multiple measurements, MORE recovers the phases of the optical-transfer-function (OTF) instead of recovering a single image of an object. Furthermore, we introduce the number of non-zero pixels (NNP) into MORE, which brings improvement on recovered images. An experimental proof is performed for dynamic objects at a frame rate of 20 Hz under white-light irradiation of more than 300 nm bandwidth.

关键词： scattering imaging white light illumination phase retrieval algorithm

Impact of Pd single-site coordination structure on catalytic performance for semihydrogenation of acetylene

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Nano Research 2024年第9期17卷 8243-8249页

作者： Yu Zeng Minqi Xia Fujie Gao Changkai Zhou Xueyi Cheng Liwei Liu Liu Jiao Qiang Wu Xizhang Wang Lijun Yang Yining Fan Zheng Hu Key laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial laboratory for Nanotechnology School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Semihydrogenation of trace acetylene in an ethylene gas stream is a vital step for the industrial production of polyethylene,in which Pd single-site catalysts(SSCs)have great ***,two Pd SSCs with different coordination structures are prepared on hierarchical nitrogen-doped carbon nanocages(hNCNC)by regulating the nitrogen species with or without using *** using dicyandiamide,the obtained Pd1-Ndicy/hNCNC SSC features the coordinated Pd by two pyridinic N and two pyrrolic N(PdN^(py)_(2)N^(pr)_(2)).Without using dicyandiamide,the obtained Pd1/hNCNC SSC features the coordinated Pd by pyridinic N and C(PdN^(py_(x)C_(4-x)),x=1-4).The former exhibits an 18-fold increase in catalytic activity compared to the *** results reveal the abundant unoccupied orbital states above the Fermi level of moiety,which can facilitate the activation of substrate molecules and dynamics of acetylene hydrogenation as supported by the combined theoretical and experimental *** addition,PdN^(py)_(2)N^(pr)_(2)the moiety presents a favorable desorption of ***,the Pd1-Ndicy/hNCNC SSC exhibits high C2H2 conversion(99%)and C2H4 selectivity(87%)at 160℃.This study demonstrates the impact of Pd single-site coordination structure on catalytic performance,which is significant for the rational design of advanced Pd SSCs on carbon-based supports.

关键词： coordination structure hierarchical nitrogen-doped carbon nanocages palladium semihydrogenation of acetylene singlesite catalysts

Lens-free wavefront shaping method for a diffuse non-lineof-sight link in visible light communication

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Chinese Optics Letters 2024年第2期22卷 81-87页

作者：陈超旭周晓萌李子薇沈超张俊文施剑阳迟楠 Key laboratory for Information Science of Electromagnetic Waves(MoE) Fudan UniversityShanghai 200433China Peng Cheng laboratory Shenzhen 518038China

In this Letter,we propose and experimentally demonstrate a lens-free wavefront shaping method that utilizes synchronized signal block beam alignment and a genetic algorithm(SSBGA)for a diffuse non-line-of-sight(NLOS)visible light communication(VLC)*** proposed method effectively controls the position and mobility of visible light beams by partitioning spatial light modulator pixels and manipulating beams to converge at distinct spatial positions,thereby enhancing wavefront shaping efficiency,which achieves a significant 23.9 dB optical power enhancement at+2 mm offset,surpassing the lens-based continuous sequence(CS)scheme by 21.7 ***+40°angle,the improvement reaches up to 11.8 dB and 16.8 dB compared to the results with and without lens-based CS,respectively.A maximum rate of 5.16 Gbps is successfully achieved using bit-power loading discrete multi-tone(DMT)modulation and the proposed SSBGA in an NLOS VLC system,which outperforms the lens-based CS by 1.07 Gbps and obtains a power saving of 55.6%during the transmission at4 *** the best of our knowledge,this is the first time that high-speed communication has been realized in an NLOS VLC system without a lens.

关键词： non-line-of-sight lens-free wavefront shaping visible light communication

Experimental demonstration of a photonic spiking neuron based on a DFB laser subject to side-mode optical pulse injection

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Science China(Information Sciences) 2024年第3期67卷 271-280页

作者： Shuiying XIANG Shuang GAO Yuechun SHI Yuna ZHANG Ziwei SONG Xingxing GUO Yahui ZHANG Yuxin MA Xiangfei CHEN State Key laboratory of Integrated Service Networks Xidian University Yongjiang laboratory 3. College of Engineering and Applied Sciences Nanjing University

We proposed and experimentally demonstrated a simple and novel photonic spiking neuron based on a distributed feedback(DFB) laser subject to side-mode optical pulse injection(SMOPI). The DFB laser chip is designed and fabricated based on asymmetric equivalent π phase shift(π-EPS) with the reconstruction-equivalent-chirp(REC) technique. Under side-mode continuous-wave(CW) optical injection,excitability pulse was experimentally observed during the dominant mode switching process due to the injection-locked effect. Based on the transition between the excitability regime and the side-mode injection locking effect, the controllable and repeatable neuron-like spiking response can be realized when external stimulus pulses are electro-optically modulated on the CW optical carrier. The experimental results show that the spike threshold, temporal integration, and refractory period, which are important spike processing mechanisms in biological neurons, can all be achieved in the optically-injected DFB laser. The experimental findings are also verified numerically with a rate equation model that considers the SMOPI. To the best of our knowledge, this is the first experimental demonstration of a photonic spiking neuron based on a DFB laser subject to SMOPI, which holds promise for realizing large-scale photonic spiking neuron arrays for hardware photonic spiking neural network chips.

关键词： neuromorphic photonics photonic spiking neuron DFB laser side-mode optical pulse injections

Multi-granularity sequence generation for hierarchical image classification

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Computational Visual Media 2024年第2期10卷 243-260页

作者： Xinda Liu Lili Wang State Key laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China Peng Cheng laboratory Shengzhen 518000China

Hierarchical multi-granularity image classification is a challenging task that aims to tag each given image with multiple granularity labels *** methods tend to overlook that different image regions contribute differently to label prediction at different granularities,and also insufficiently consider relationships between the hierarchical multi-granularity *** introduce a sequence-to-sequence mechanism to overcome these two problems and propose a multi-granularity sequence generation(MGSG)approach for the hierarchical multi-granularity image classification ***,we introduce a transformer architecture to encode the image into visual representation ***,we traverse the taxonomic tree and organize the multi-granularity labels into sequences,and vectorize them and add positional *** proposed multi-granularity sequence generation method builds a decoder that takes visual representation sequences and semantic label embedding as inputs,and outputs the predicted multi-granularity label *** decoder models dependencies and correlations between multi-granularity labels through a masked multi-head self-attention mechanism,and relates visual information to the semantic label information through a crossmodality attention *** this way,the proposed method preserves the relationships between labels at different granularity levels and takes into account the influence of different image regions on labels with different *** on six public benchmarks qualitatively and quantitatively demonstrate the advantages of the proposed *** project is available at https://***/liuxindazz/mgs.

关键词： hierarchical multi-granularity classification vision and text transformer sequence generation fine-grained image recognition cross-modality attenti

Contrasting physical mechanisms of yellowfin tuna fluctuations between the western and eastern Indian Ocean

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Journal of Oceanology and Limnology 2024年第3期42卷 960-971页

作者： Peng LIAN Le GAO Key laboratory of Ocean Observation and Forecasting and Key laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China laboratory for Ocean Dynamics and Climate Laoshan LaboratoryQingdao 266061China

As an economically critical pelagic migratory species,yellowfin tuna(Thunnus albacores,YFT)is very sensible to physical and environmental conditions,such as sea surface temperature(SST),ocean heat content(OHC),and the mixed layer depth(MLD).We investigated the impact of SST,OHC,and MLD on fluctuations of YFT catch in the western/eastern Indian Ocean using the long time series of 63-year environmental and YFT *** found that the impact of SST on YFT was heavily overestimated in the past,and MLD plays a more critical role in the YFT catch *** the MLD deepens(>34.8 m),SST was more influential in predicting the catches of YFT than OHC in the western Indian Ocean,and OHC was more critical to YFT than SST in the eastern Indian ***,when the MLD shallows(<34.8 m),MLD was more vital to predict the catch per unit effort(CPUE)of YFT than SST/OHC in the *** 2000,there was an asynchronous pattern of YFT CPUE induced by higher frequency variations and ocean hiatus of SST/OHC signals in the western and eastern Indian Oceans *** impact of the subsurface hiatus may induce the decrease of YFT in the eastern Indian *** above findings clarified a non-stationary relationship between the environmental factors and catches of YFT and provided new insights into variations in YFT abundance.

关键词： yellowfin tuna Indian Ocean sea surface temperature(SST) ocean heat content(OHC) mixed layer depth(MLD) hiatus

Brain circuits for retching-like behavior

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National Science Review 2024年第1期11卷 145-160页

作者： Lifang Huo Zhimin Ye Meiling Liu Ziqing He Meizhu Huang Dapeng Li Qian Wu Qian Wang Xiaoqun Wang Peng Cao Ji Dong Congping Shang School of Basic Medical Sciences Guangzhou National Laboratory The Fifth Afflliated Hospital Guangzhou Medical University Bioland laboratory (Guangzhou Regenerative Medicine and Health Guangdong laboratory) Department of Neurobiology School of Basic Medical Sciences Beijing Key Laboratory of Neural Regeneration and Repair Advanced Innovation Center for Human Brain Protection Capital Medical University State Key laboratory of Cognitive Neuroscience and Learning IDG/McGovern Institute for Brain Research Beijing Normal University Changping Life Science laboratory National Institute of Biological Sciences

Nausea and vomiting are important defensive responses to cope with pathogens and toxins that invade the body. The nucleus of the solitary tract(NTS) is important for initiating these responses. However, the molecular heterogeneities and cellular diversities of the NTS occlude a better understanding of these defensive responses. Here, we constructed the single-nucleus transcriptomic atlas of NTS cells and found multiple populations of NTS neurons that may be involved in these defensive responses. Among these, we identified Calbindin1-positive(Calb1+) NTS neurons that are molecularly distinct from Tac1+*** Calb1+neurons are critical for nausea and retching induced by cereulide; an emetic toxin secreted by Bacillus Cereus. Strikingly, we found that cereulide can directly modulate vagal sensory neurons that innervate Calb1+NTS neurons, a novel mechanism distinct from that for nausea and retching induced by Staphylococcal enterotoxin A. Together, our transcriptomic atlas of NTS neurons and the functional analyses revealed the neural mechanism for cereulide-induced retching-like behavior. These results demonstrate the molecular and cellular complexities in the brain that underlie defensive responses to the diversities of pathogens and toxins.

关键词： vomiting nausea nucleus of the solitary tract Calbindin1 neural circuits

Wall temperature effects on the stability of leeward vortices of a blunt inclined cone

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Acta Mechanica Sinica 2024年第7期40卷 29-42页

作者： Ligeng Zhang Bingbing Wan Siwei Dong Jianqiang Chen Xi Chen State Key laboratory of Aerodynamics Mianyang 621000China

Streamwise vortex instability is one of the most potent mechanisms for the transition of the three-dimensional boundary *** using the global stability analysis methods,stability characteristics of the leeward vortex over a blunt cone with an angle of attack under a typical wind tunnel condition are studied and are compared to the case with a smaller wall temperature ratio(corresponding to a flight condition).The vortical structure features inward and outward vortices,similar to that in the flight *** the flight condition,the outward vortices appear stronger than the inward vortices,resulting in stronger outer-mode *** the inner mode is heavily stabilized compared to the flight condition,it can still radiate apparent *** acoustic sources are computed based on Lighthill's acoustic analogy,showing that the entropy term measuring the deviation from the isentropic relation is *** Mack second mode is shown to most likely trigger the transition in the flight condition,it is absent in the wind tunnel condition,and a shear-layer mode turns out to be the most dangerous ***,the instability frequencies and growth rates of the wind tunnel case are much smaller than those of the flight case,indicating that wall heating may stabilize the leeward vortices.

关键词： Instability of streamwise vortices Hypersonic boundary layer flow Spatial BiGlobal method PSE3D method

Epigenetic control on transcription of vernalization genes and whole-genome gene expression profile induced by vernalization in common wheat

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Plant Diversity 2024年第3期46卷 386-394页

作者： Yunzhen Li Liujie Jin Xinyu Liu Chao He Siteng Bi Sulaiman Saeed Wenhao Yan National Key laboratory of Crop Genetic Improvement Hubei Hongshan LaboratoryHuazhong Agricultural UniversityWuhan 430070China

Vernalization is necessary for winter wheat to ***,it is unclear whether vernalization is also required for spring wheat,which is frequently sown in fall,and what molecular mechanisms underlie the vernalization response in wheat *** this study,we examined the molecular mechanisms that regulate vernalization response in winter and spring wheat *** this purpose,we determined how major vernalization genes(VRN1,VRN2,and VRN3)respond to vernalization in these varieties and whether modifications to histones play a role in changes in gene *** also identified genes that are differentially regulated in response to vernalization in winter and spring wheat *** found that in winter wheat,but not in spring wheat,VRN1 expression decreases when returned to warm temperature following *** finding may be associated with differences between spring and winter wheat in the levels of tri-methylation of lysine 27 on histone H3(H3K27me3)and tri-methylation of lysine 4 on histone H3(H3K4me3)at the VRN1 *** of winter wheat transcriptomes before and after vernalization revealed that vernalization influences the expression of several genes,including those involved in leucine catabolism,cysteine biosynthesis,and flavonoid *** findings provide new candidates for further study on the mechanism of vernalization regulation in wheat.

关键词： Wheat Vernalization VRN1 Histone modification Regulate network