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Self-synchronized multi-color Q-switched fiber laser using a parallel-integrated fiber Bragg grating

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Chinese Optics Letters 2024年第6期22卷 148-153页

作者： Chao Zeng Guangwei Yang Dong Li Pengtao Luo Ruohui Wang Yueqing Du Dong Mao Jianlin Zhao Key Laboratory of Light Field Manipulation and Information Acquisition Ministry of Industry and Information TechnologySchool of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an 710072China research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China School of Physics Northwest UniversityXi’an 720127China

We demonstrate an intracavity self-synchronized multi-color Q-switched fiber laser using a parallel-integrated fiber Bragg grating(PI-FBG), fabricated by a femtosecond laser with a point-by-point parallel inscription method. The multi-color Q-switched pulses can be always self-synchronized when the group delay differences between neighboring spectra range from-3.4 to 3.4 *** starting and evolution dynamics indicate that the saturable absorption effect of the carbon nanotube plays a dual role: synchronously triggering the startup of the pulse at successive colors by active Q-switching and spontaneously compensating to some extent the temporal walk-off of the multi-color pulses through the cross saturable absorption modulation. This work unveils the intracavity self-synchronization mechanism of the multi-color Q-switched pulses and also demonstrates the potential of PI-FBGs for the customizable generation of the synchronized multi-color pulse in a single cavity.

关键词： synchronized pulse sources Q-switched fiber lasers saturable absorption effect fiber Bragg grating

Stimulation and imaging of neural cells via photonic nanojets

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Photonics research 2024年第8期12卷 1604-1609页

作者： HENG LI XIXI CHEN TIANLI WU ZHIYONG GONG JINGHUI GUO XIAOSONG BAI JIAWEI LI YAO ZHANG YUCHAO LI BAOJUN LI Guangdong Provincial Key Laboratory of Nanophotonic Manipulation Institute of NanophotonicsCollege of Physics&Optoelectronic EngineeringJinan UniversityGuangzhou 511443China School of Medicine The Chinese University of Hong KongShenzhen 518172China InnerMedical Co. Ltd.Shenzhen 518055China

Various neuromodulation techniques have been developed to modulate the peak activity of neurons,thereby regulating brain function and alleviating neurological ***,neuronal stimulation and imaging have significantly contributed to the understanding and treatment of these ***,we propose utilizing photonic nanojets for optical stimulation and imaging of neural *** application of resin microspheres as microlenses enhances fluorescence imaging of neural lysosomes,mitochondria,and actin filaments by generating photonic ***,optical tweezers can precisely manipulate the microlenses to locate specific targets within the cell for real-time stimulation and *** focusing capabilities of these microlenses enable subcellular-level spatial precision in stimulation,allowing highly accurate targeting of neural cells while minimizing off-target ***,fluorescent signals during neural cell stimulation can be detected in real-time using these *** proposed method facilitates investigation into intercellular signal transmission among neural cells,providing new insights into the underlying mechanisms of neuronal cell activities at a subcellular level.

关键词： stimulation neural utilizing

Effects of dynamical spanwise retraction and stretch on flapping-wing forward flights

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Chinese Journal of Aeronautics 2024年第4期37卷 181-202页

作者： Kang LIU Bifeng SONG Ang CHEN Zhihe WANG Dong XUE Wenqing YANG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Intelligent Aircraft research Center Chengdu Technological UniversityChengdu 610031China research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China Harbin Institute of Technology Shenzhen 518055China

Birds and bats retract and stretch their wings dynamically during each flap in level flights, implying intriguing mechanisms for the aerodynamic performance improvement of flapping wings. A numerical investigation into the aerodynamic effects of such bio-inspired concept in forward flights has been performed based on a three-dimensional wing in plunging motion and a twosection wing in flapping motion. The currently considered Reynolds number and Strouhal number are Re=1.5×10^(5) and St=0.3, respectively. During the research, the mean angle of attack is varied in relatively wide ranges to achieve lift-thrust interconversion for the wings. The conclusive results show that dynamical spanwise retraction and stretch has induced three absolutely desirable scenarios for the oscillating wings in forward flights, namely producing more lift and consuming less power for a given thrust generation, producing more thrust and consuming less power for a given lift generation, and producing more lift and more thrust while consuming less power. Furthermore,the morphing wings have alleviated periodical aerodynamic load fluctuations compared with the non-morphing baseline. The mechanism of the aerodynamic effects of the bionic morphing mode is analyzed with the aid of field visualization. The current article is the first to reveal the absolute advantages of the bionic spanwise morphing. Hopefully, it may help comprehend the behaviors of natural fliers and provide inspirations for performance enhancement of micro artificial flappingwing vehicles.

关键词： Flapping wing Morphing wing Bionic Aerodynamics Vortex Flight

Bayesian partial pooling to reduce uncertainty in overcoring rock stress estimation

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1192-1201页

作者： Yu Feng Ke Gao Suzanne Lacasse Norwegian Geotechnical Institute OsloNorway Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhenChina

The state of in situ stress is a crucial parameter in subsurface engineering,especially for critical projects like nuclear waste *** one of the two ISRM suggested methods,the overcoring(OC)method is widely used to estimate the full stress tensors in rocks by independent regression analysis of the data from each OC ***,such customary independent analysis of individual OC tests,known as no pooling,is liable to yield unreliable test-specific stress estimates due to various uncertainty sources involved in the OC *** address this problem,a practical and no-cost solution is considered by incorporating into OC data analysis additional information implied within adjacent OC tests,which are usually available in OC measurement ***,this paper presents a Bayesian partial pooling(hierarchical)model for combined analysis of adjacent OC *** performed five case studies using OC test data made at a nuclear waste repository research site of *** results demonstrate that partial pooling of adjacent OC tests indeed allows borrowing of information across adjacent tests,and yields improved stress tensor estimates with reduced uncertainties simultaneously for all individual tests than they are independently analysed as no pooling,particularly for those unreliable no pooling stress estimates.A further model comparison shows that the partial pooling model also gives better predictive performance,and thus confirms that the information borrowed across adjacent OC tests is relevant and effective.

关键词： Overcoring stress measurement Uncertainty reduction Partial pooling Bayesian hierarchical model Nuclear waste repository

Precise immobilization of metal single atoms into a porphyrinic metal-organic framework for an efficient alkene hydrosilylation

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Nano research 2024年第7期17卷 5914-5921页

作者： Chun-Ying Chen Qi-Jie Mo Fu-Zhen Li Hai-Li Song Li Zhang MOE Laboratory of Bioinorganic and Synthetic Chemistry Lehn Institute of Functional MaterialsSchool of ChemistrySun Yat-Sen UniversityGuangzhou 510006China

Alkene hydrosilylation is one of the most concise and atom-economical methods to synthesize organosilicon ***,we reported the precise immobilization of metal single atoms(M-SAs;M=Ru,Rh,Ir,Pd,Pt,and Au)into a porphyrinic metalorganic framework(MOF)of PCN-222(PCN=porous coordination network),and then applied the resultant MOF composites of M-SAs@PCN-222 to alkene *** solvent-free conditions,Pt-SAs@PCN-222 displayed an especially high catalytic efficiency with the turnover frequency up to 119 s−1 and the maximum turnover number of 906,250 at room *** and theoretical studies revealed that there existed strong interactions between Pt-SAs@PCN-222 and the substrates,which helped to condense the substrates in the cavities of the porous *** density functional theory calculations and molecular dynamics simulations disclosed that PCN-222 could transfer electrons to Pt-SAs to enhance the silane oxidative addition and drive the reaction to proceed smoothly via Chalk–Harrod pathway.

关键词： alkene hydrosilylation single atom catalysts metal-organic frameworks precision chemistry synergistic catalysis

Lipase and photodecarboxylase coexpression: A potential strategy for alkane-based biodiesel production from natural triglycerides

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Chinese Journal of Chemical Engineering 2024年第3期67卷 238-246页

作者： Yong-Yi Zeng Xin-Yi Xu Jin-Xuan Xie Wen-Li Chen Lan Liu Xin-Jian Yin Bi-Shuang Chen School of Marine Sciences Sun Yat-Sen UniversityZhuhai 519080China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China

Alkane-based biodiesel is considered the next generation of biodiesel owing to its potential environmental benefits and the fact that it exhibits much higher specific caloric values than traditional ***,the formidable obstacle impeding the commercialization of this cutting-edge fuel alternative lies in the cost associated with its *** this study,an engineered strain Escherichia coli(***)showcasing harmonized coexpression of a lipase(from Thermomyces lanuginosus lipase,TLL)and a fatty acid photodecarboxylase(from Chlorella variabilis,CvFAP)was first constructed to transform triglycerides into *** potential of *** BL21(DE3)/pRSFDuet-1-TLL-CvFAP for alkane synthesis was evaluated with tripalmitin as a model substrate under various process *** a comprehensive examination of the reaction parameters,the scope of the biotransformation was expanded to‘real’substrates(vegetable oils).The results showed that bioderived oils can be transformed into alkanes with high yields(0.80-10.20 mmol·L^(-1))under mild conditions(35℃,pH 8.0,and 36 h)and blue light *** selected processes were performed on an increased lab scale(up to 100 ml)with up to 24.77 mmol·L^(-1) tripalmitin,leading to a yield of 18.89 mmol·L^(-1) *** the employment of a method for efficiently producing alkanes under mild conditions and a simple procedure to isolate alkanes from the reaction system,the utilization of sustainable biomass as a fundamental feedstock emerges as the primary solution to lower the cost of alkane-based ***,this study proposes a readily implementable and highly effective approach for alkane-based biodiesel production.

关键词： Alkane-based biodiesel Renewable biomass Co-overexpression Lipase Photodecarboxylase

Short-term Residential Load Forecasting Based on K-shape Clustering and Domain Adversarial Transfer Network

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1239-1249页

作者： Jizhong Zhu Yuwang Miao Hanjiang Dong Shenglin Li Ziyu Chen Di Zhang School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong KongChina

In recent years,the expansion of the power grid has led to a continuous increase in the number of consumers within the distribution ***,due to the scarcity of historical data for these new consumers,it has become a com-plex challenge to accurately forecast their electricity demands through traditional forecasting *** paper proposes an innovative short-term residential load forecasting method that harnesses advanced clustering,deep learning,and transfer learning technologies to address this *** begin,this paper leverages the domain adversarial transfer *** employs limited data as target domain data and more abundant data as source domain data,thus enabling the utilization of source do-main insights for the forecasting task of the target ***,a K-shape clustering method is proposed,which effec-tively identifies source domain data that align optimally with the target domain,and enhances the forecasting ***-sequently,a composite architecture is devised,amalgamating at-tention mechanism,long short-term memory network,and seq2seq *** composite structure is integrated into the domain adversarial transfer network,bolstering the perfor-mance of feature extractor and refining the forecasting *** illustrative analysis is conducted using the residential load dataset of the Independent System Operator to validate the proposed method *** the case study,the relative mean square error of the proposed method is within 30 MW,and the mean absolute percentage error is within 2%.A signifi-cant improvement in accuracy,compared with other compara-tive experimental results,underscores the reliability of the pro-posed *** findings unequivocally demonstrate that the proposed method advocated in this paper yields superior fore-casting results compared with prevailing mainstream forecast-ing methods.

关键词： Load forecasting domain adversarial K-shape clustering long short-term memory network seq2seq network attention mechanism

Geometric Constraints for Global Regularity of 3D Shear Thickening Fluids

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 205-210页

作者： Jia-qi Yang research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518063China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China

We consider the relation between the direction of the vorticity and the global regularity of 3D shear thickening *** is showed that a weak solution to the non-Newtonian incompressible fluid in the whole space is stron... 详细信息

关键词： direction of the vorticity non-Newtonian fluid global regularity

Development of MoS_(2)-stainless steel catalyst by 3D printing for efficient destruction of organics via peroxymonosulfate activation

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Journal of Environmental Sciences 2024年第1期135卷 108-117页

作者： Yufeng Liu Jianhui Xu Xin Fu Pengxu Wang Dan Li Yunfei Zhang Shenggui Chen Chunhui Zhang Peng Liu School of Environment and Civil Engineering Dongguan University of TechnologyDongguan 523808China School of Art and Design Guangzhou Panyu PolytechnicGuangzhou 511483China Dongguan Institute of Science and Technology Innovation Dongguan University of TechnologyDongguan 523808China School of Mechanical Engineering Dongguan University of TechnologyDongguan 523808China

Herein,a novel MoS_(2)-stainless steel composite material was first synthetized via a 3D printing method(3DP MoS_(2)-SS)for peroxymonosulfate(PMS)activation and organics *** with MoS_(2)-SS powder/PMS system(0.37 g/(m^(2)/min)),4.3-fold higher k_(FLO)/S_(BET)value was obtained in 3DP MoS_(2)-SS/PMS system(1.60 g/(m^(2)/min),resulting from the superior utilization of active *** observed that 3DP MoS_(2)-SS significantly outperformed the 3DP SS due to the enhanced electron transfer rate and increased active ***,Mo^(4+)facilitated the Fe^(2+)/Fe^(3+)cycle,resulting in the rapid degradation of florfenicol(FLO).Quenching experiments and electron paramagnetic resonance spectra indicated that·OH,SO_(4)·^(-),O_(2)·^(-)and^(1)O_(2)were involved in the degradation of *** effect of influencing factors on the degradation of FLO were evaluated,and the optimized degradation efficiency of 98.69%was achieved at 1 mM PMS and pH of *** degradation products were detected by UPLC/MS analyses and several possible degradation pathways were proposed to be the cleavage of C-N bonds,dechlorination,hydrolysis,defluorination and *** addition,3DP MoS_(2)-SS/PMS system also demonstrated superior degradation performance for 2-chlorophenol,acetaminophen,ibuprofen and *** study provided deep insights into the MoS_(2)-SS catalyst prepared by 3DP technology for PMS activation and FLO-polluted water treatment.

关键词： 3D printing Stainless steel MoS_(2) Peroxymonosulfate activation Degradation mechanism