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Internal phase control of fiber laser array based on photodetector array

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Chinese Physics B 2024年第7期33卷 320-326页

作者：靳凯凯龙金虎常洪祥粟荣涛张嘉怡陈思雨马阎星周朴 College of Advanced interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Nanhu Laser Laboratory National University of Defense TechnologyChangsha 410073China Hunan Provincial Key Laboratory of High Energy Laser Technology National University of Defense TechnologyChangsha 410073China

Coherent beam combining(CBC) of fiber laser array is a promising technique to realize high output power while maintaining near diffraction-limited beam quality. To implement CBC, an appropriate phase control feedback structure should be established to realize phase-locking. In this paper, an innovative internal active phase control CBC fiber laser array based on photodetector array is proposed. The dynamic phase noises of the laser amplifiers are compensated before being emitted into free space. And the static phase difference compensation of emitting laser array is realized by interference measurement based on photodetector array. The principle of the technique is illustrated and corresponding simulations are carried out, and a CBC system with four laser channels is built to verify the technique. When the phase controllers are turned on, the phase deviation of the laser array is less than λ/20, and ~ 95% fringe contrast of the irradiation distribution is obtained. The technique proposed in this paper could provide a reference for the system design of a massive high-power CBC system.

关键词： fiber laser laser array coherent beam combining internal phase control

Laser constructed vacancy-rich TiO_(2-x)/Ti microfiber via enhanced interfacial charge transfer for operando extraction-SERS sensing

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Chinese Chemical Letters 2024年第9期35卷 187-192页

作者： Ying Hou Zhen Liu Xiaoyan Liu Zhiwei Sun Zenan Wang Hong Liu Weijia Zhou Institute for Advanced interdisciplinary Research(iAIR) School of Chemistry and Chemical EngineeringUniversity of JinanJi’nan 250022China State Key Laboratory of Crystal Materials Shandong UniversityJi’nan 250100China Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China

Semiconductor-molecule surface-enhanced Raman scattering(SERS),especially the stronger interfacial charge transfer process(ICTP),represents a frontier in the field of SERS with spectral reproducibility and unparalleled ***,through a laser microfabrication method in situ,the free-standing,super hydrophilic and vacancy-rich TiO_(2-x)/Ti is successfully *** blue TiO_(x)/Ti(B-TiO_(x)/Ti)as preconcentrated substrate,a nanomolar-level limit of detection of 12 nmol/L at 1385 cm–1,is confirmed using crystal violet(CV)bacteriostat as a model under 532 nm ***,the results demonstrate that the SERS enhancement mechanism is via the moderate adulteration of oxygen vacancy,which leads to a narrow value of band gap and increases the ICTP of substrate to *** a hand-held extractor assembled with B-TiO_(x)/Ti microfiber,the operando analysis of mixtures distributed information excited in different parts of Asian carp is facilely *** work guides the controlled synthesis of vacancy-rich TiO_(2-x)/Ti nanostructure and its application in ultrasensitive extraction-SERS *** also provides the direction for the rapid and operando transmission of biological information with temporal and spatial concentration distribution in human tissues by highly sensitized materials.

关键词： Defect engineering TiO_(2-x)/Ti microfiber Laser microfabrication Surface-enhanced Raman scattering Solid phase microextraction Operando sensing

Density peak clustering using tensor network

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Science China(Information Sciences) 2024年第3期67卷 321-322页

作者： Xiao SHI Yun SHANG Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences National Center for Mathematics and interdisciplinary Sciences Key Laboratory of ManagementDecision and Information SystemsAcademy of Mathematics and Systems ScienceChinese Academy of Sciences

Tensor networks have been a powerful tool in simulating many-body physics and have recently gained recognition in the machine learning community due to their remarkable representation capabilities. However, using tens... 详细信息

关键词： Tensors

A robust vector tracking loop structure based on potential bias analysis

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Chinese Journal of Aeronautics 2024年第4期37卷 405-420页

作者： Qiongqiong JIA Yiran LUO Bing XU Li-Ta HSU Renbiao WU Tianjin Key Lab for Advanced Signal Processing Civil Aviation University of ChinaTianjin 300300China interdisciplinary Division of Aeronautical and Aviation Engineering The Hong Kong Polytechnic University999077Hong KongChina Department of Geomatics Engineering University of CalgaryCalgary T2N1N4Canada

This paper proposes a robust vector tracking loop structure based on potential bias analysis. The influence of four kinds of biases on the existing two implementations of Vector Tracking Loops(VTLs) is illustrated by theoretical analysis and numerical simulations, and the following findings are obtained. Firstly, the initial user state bias leads to steady navigation solution bias in the relative VTL, while new measurements can eliminate it in the absolute VTL. Secondly, the initial code phase bias is transferred to the following navigation solutions in the relative VTL, while new measurements can eliminate it in the absolute VTL. Thirdly, the user state bias induced by erroneous navigation solution of VTLs can be eliminated by both of the two VTLs. Fourthly,the multipath/NLOS likely affects the two VTLs, and the induced tracking bias in the duration of the multipath/NLOS would decrease the performance of VTLs. Based on the above analysis,a robust VTL structure is proposed, where the absolute VTL is selected for its robustness to the two kinds of initialization biases;meanwhile, the instant bias detection and correction method is used to improve the performance of VTLs in the duration of the multipath/NLOS. Numerical simulations and experimental results verify the effectiveness of the proposed robust VTL structure.

关键词： Global Navigation Satellite System(GNSS) Vector Tracking Loop(VTL) Multipath Non-Line-of-Sight(NLOS) Tracking bias propagation Least Absolute Shrinkage and Selection Operator(LASSO)

Coherent beam combining of two all‑PM thulium‑doped fiber chirped pulse amplifiers

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Frontiers of Optoelectronics 2024年第2期17卷 33-42页

作者： Bo Ren Hongxiang Chang Can Li Tao Wang Kaikai Jin Jiayi Zhang Kun Guo Rongtao Su Jinyong Leng Pu Zhou College of Advanced interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Nanhu Laser Laboratory National University of Defense TechnologyChangsha 410073China Hunan Provincial Key Laboratory of High Energy Laser Technology National University of Defense TechnologyChangsha 410073China

In this paper,we report a coherent beam combining(CBC)system that involves two thulium-doped all-polarization maintaining(PM)fiber chirped pulse *** phase-locking the two channels via a fiber stretcher by using the stochastic parallel gradient descent(SPGD)algorithm,a maximum average power of 265 W is obtained,with a CBC efficiency of 81%and a residual phase error of λ/*** de-chirping by a pair of diffraction gratings,the duration of the combined laser pulse is compressed to 690 *** into account the compression efficiency of 90%and the main peak energy proportion of 91%,the corresponding peak power is calculated to be 4 *** laser noise characteristics before and after CBC are examined,and the results indicate that the CBC would degrade the low frequency relative intensity noise(RIN),of which the integration is 1.74%in[100 Hz,2 MHz]at the maximum combined output *** addition,the effects of the nonlinear spectrum broadening during chirped pulse amplification on the CBC efficiency are also investigated,showing that a higher extent of pulse stretching is effective in alleviating the spectrum broadening and realizing a higher output power with decent combining efficiency.

关键词： Coherent beam combining Thulium-doped fiber laser High-average power Chirped pulse amplifier

Typhoon-and pollution-driven enhancement of reactive bromine in the mid-latitude marine boundary layer

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National Science Review 2024年第4期11卷 93-101页

作者： Shanshan Wang Qinyi Li Ruifeng Zhang Anoop Sharad Mahajan Swaleha Inamdar Nuria Benavent Sanbao Zhang Ruibin Xue Jian Zhu Chenji Jin Yan Zhang Xiao Fu Alba Badia Rafael P.Fernandez Carlos A.Cuevas Tao Wang Bin Zhou Alfonso Saiz-Lopez Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3) Department of Environmental Science and Engineering Fudan University Institute of Eco-Chongming(IEC) Department of Atmospheric Chemistry and Climate Institute of Physical Chemistry Blas CabreraCSIC Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Environment Research Institute Shandong University Centre for Climate Change Research Indian Institute of Tropical MeteorologyMinistry of Earth Sciences Department of Chemistry University of Colorado Boulder Institute of Environment and Ecology Tsinghua Shenzhen International Graduate SchoolTsinghua University Sostenipra Research Group Institute of Environmental Science and Technology(ICTA)Universitat Autonoma de Barcelona(UAB) Institute for interdisciplinary Science (ICB) National Research Council (CONICET)

Tropospheric reactive bromine is important for atmospheric chemistry,regional air pollution,and global *** studies have reported measurements of atmospheric reactive bromine species in different environments,and proposed their main sources,***-salt aerosol（SSA）,oceanic biogenic activity,polar snow/ice,and *** and other strong cyclonic activities（***） induce abrupt changes in different earth system processes,causing widespread destructive ***,the role of typhoons in regulating reactive bromine abundance and sources remains ***,we report field observations of bromine oxide（BrO）,a critical indicator of reactive bromine,on the Huaniao Island（HNI）in the East China Sea in July *** observed high levels of BrO below 500 m with a daytime average of9.7±4.2 pptv and a peak value of ～26 pptv under the influence of a *** field measurements,supported by model simulations,suggest that the typhoon-induced drastic increase in wind speed amplifies the emission of SSA,significantly enhancing the activation of reactive bromine from SSA *** also detected enhanced BrO mixing ratios under high NOxconditions（ppbv level） suggesting a potential pollution-induced mechanism of bromine release from *** elevated levels of atmospheric bromine noticeably increase ozone destruction by as much as ～40% across the East China *** the high frequency of cyclonic activity in the northern hemisphere,reactive bromine chemistry is expected to play a more important role than previously thought in affecting coastal air quality and atmospheric oxidation *** suggest that models need to consider the hitherto overlooked typhoon-and pollution-mediated increase in reactive bromine levels when assessing the synergic effects of cyclonic activities on the earth system.

关键词： reactive bromine atmospheric chemistry marine boundary layer atmospheric oxidation capacity marine emission

A flexible,modular and versatile functional part assembly toolkit for gene cluster engineering in Streptomyces

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Synthetic and Systems Biotechnology 2024年第1期9卷 69-77页

作者： Xuejin Zhao Yeqing Zong Qiuli Lou Chenrui Qin Chunbo Lou CAS Key Laboratory of Pathogenic Microbiology and immunology Institute of MicrobiologyChinese Academy of SciencesBeijing100101China CAS Key Laboratory of Microbial Physiological and Metabolic Engineering Institute of MicrobiologyChinese Academy of SciencesBeijing100101China Center for Cell and Gene Circuit Design Key Laboratory of Quantitative Synthetic BiologyShenzhen Institute of Synthetic BiologyShenzhen Institutes of Advanced TechnologyChinese Academy of Sciences1068 Xueyuan AvenueUniversity TownNanshanShenzhen518055China Peking-Tsinghua Joint Center for Life Sciences Peking UniversityBeijing100871China Center for Quantitative Biology Academy for Advanced Interdisciplinary StudiesSchool of PhysicsPeking UniversityBeijing100871China College of Life Sciences University of Chinese Academy of SciencesBeijing100149China

Streptomyces has enormous potential to produce novel natural products(NPs)as it harbors a huge reservoir of uncharacterized and silent natural product biosynthetic gene clusters(BGCs).However,the lack of efficient gene cluster engineering strategies has hampered the pace of new drug ***,we developed an easy-to-use,highly flexible DNA assembly toolkit for gene cluster *** DNA assembly toolkit is compatible with various DNA assembling approaches including Biobrick,Golden Gate,CATCH,yeast homologous recombination-based DNA assembly and homing endonuclease-mediated *** compatibility offers great flexibility in handling multiple genetic parts or refactoring large gene *** demonstrate the utility of this toolkit,we quantified a library of modular regulatory parts,and engineered a gene cluster(act)using characterized promoters that led to increased ***,this work provides a powerful part assembly toolkit that can be used for natural product discovery and optimization in Streptomyces.

关键词： Streptomyces Standard toolkit DNA assembly Gene cluster Synthetic biology

Harnessing novel engineered feeder cells expressing activating molecules for optimal expansion of NK cells with potent antitumor activity

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Cellular & Molecular immunology 2022年第2期19卷 296-298页

作者： Bokyung Min Bitna Yang You-Sun Kim Gyeong Min Park HyunAh Kim Hyojin Kim Eun-Ji Kim Yu Kyeong Hwang Eui-Cheol Shin Sungyoo Cho BioMedical Science and Engineering interdisciplinary program KAISTDaejeonKorea Cell Therapy Research Center GC LabCellYonginKorea Laboratory of immunology and Infectious Diseases Graduate School of Medical Science and EngineeringKAISTDaejeonKorea

Natural killer(NK)cells play an important role in the antitumor immune response as the major cytotoxic lymphocytes in the innate immune *** cells without any genetic modifications have been used for both autologous and allogeneic ***,many reports have suggested that allogeneic NK cells can reduce the recurrence of disease and improve survival through a graft-versus-leukemia effect without GVHD[1,2].

关键词： killer expressing optimal

REFINED CONSERVATION LAW FOR AN EVEN ORDER ELLIPTIC SYSTEM WITH ANTISYMMETRIC POTENTIAL

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Acta Mathematica Scientia 2024年第6期44卷 2111-2124页

作者：郭常予向长林郑高峰 Research Center for Mathematics and interdisciplinary Sciences Shandong University Department of Physics and Mathematics University of Eastern Finland Three Gorges Mathematical Research Center China Three Gorges University School of Mathematics and Statistics Central China Normal University

Conservation law plays a very important role in many geometric variational problems and related elliptic *** this note,we refine the conservation law obtained by Lamm-Rivière for fourth order systems and de Longuevil... 详细信息

关键词： 35J35 58E20 antisymmetric potential conservation law even order elliptic system Uhlenbeck’s gauge transform weak compactness