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Mastering air combat game with deep reinforcement learning

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Defence Technology（防务技术） 2024年第4期34卷 295-312页

作者： Jingyu zhu Minchi Kuang Wenqing Zhou Heng Shi Jihong zhu Xu Han Department of Precision Instruments Tsinghua UniversityBeijing 100084China Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China Chengdu Aircraft Design&Research Institute Aviation Industry Corporation of ChinaChengdu 610000China

Reinforcement learning has been applied to air combat problems in recent years,and the idea of curriculum learning is often used for reinforcement learning,but traditional curriculum learning suffers from the problem of plasticity loss in neural networks.Plasticity loss is the difficulty of learning new knowledge after the network has converged.To this end,we propose a motivational curriculum learning distributed proximal policy optimization(MCLDPPO)algorithm,through which trained agents can significantly outperform the predictive game tree and mainstream reinforcement learning methods.The motivational curriculum learning is designed to help the agent gradually improve its combat ability by observing the agent's unsatisfactory performance and providing appropriate rewards as a guide.Furthermore,a complete tactical maneuver is encapsulated based on the existing air combat knowledge,and through the flexible use of these maneuvers,some tactics beyond human knowledge can be realized.In addition,we designed an interruption mechanism for the agent to increase the frequency of decisionmaking when the agent faces an emergency.When the number of threats received by the agent changes,the current action is interrupted in order to reacquire observations and make decisions again.Using the interruption mechanism can significantly improve the performance of the agent.To simulate actual air combat better,we use digital twin technology to simulate real air battles and propose a parallel battlefield mechanism that can run multiple simulation environments simultaneously,effectively improving data throughput.The experimental results demonstrate that the agent can fully utilize the situational information to make reasonable decisions and provide tactical adaptation in the air combat,verifying the effectiveness of the algorithmic framework proposed in this paper.

关键词： Air combat MCLDPPO Interruption mechanism Digital twin Distributed system

Isolation performances and optimization of triple quasi-zero stiffness isolators

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 124-141页

作者： Yuntian Zhang Guangnan zhu Qingjie Cao School of Astronautics Harbin Institute of TechnologyHarbin 150001China

In this paper,triple quasi-zero stiffness(QZS)passive vibration isolators whose restoring force curve has a three-stage softening effect are proposed.Multi-coupled SD oscillators with three independent geometrical parameters are used as negative stiffness mechanisms to achieve QZS characteristics at the origin and symmetrical positions on both sides of the origin.Isolation performances of different triple QZS isolators are analyzed to show influences of the selection of QZS regions away from the origin on the range of isolation regions.Pareto optimizations of system parameters are carried out to get a larger range of small restoring force regions and small stiffness regions.Isolation performances of two triple QZS isolators are discussed to show the influence of different Pareto optimization solutions through the comparisons with single and double QZS isolators.Results showed that triple QZS isolators have both the advantages of single and double QZS isolators which results in better isolation performances under both small and large excitation amplitudes.An improvement in isolation performances for triple QZS isolators is found with the decrease in average stiffness due to the appearance of two symmetrical QZS regions away from the origin.Larger displacements of QZS regions away from the origin result in better isolation performances when excitation amplitude is large,and triple QZS characteristics are similar to double QZS isolators at this time.Smaller restoring forces of QZS regions away from the origin lead to better isolation performances when excitation amplitude is small,and triple QZS characteristics are similar to single QZS isolators at this moment.Compared with the decrease in average stiffness,the improvement of isolation performances shows a hysteresis phenomenon due to the difference between static and dynamic characteristics.

关键词： triple quasi-zero stiffness vibration isolation Pareto optimization force transmissibility geometrical nonlinear

The effect of glutathione on glucosinolate biosynthesis through the sulfur assimilation pathway in pakchoi associated with the growth conditions

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Horticultural Plant Journal 2024年第2期10卷 473-487页

作者： Biao zhu Zhile Liang Dan Wang Chaochao He zhujun zhu Jing Yang Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable Ministry of Agriculture and Rural AffairsCollaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang ProvinceCollege of Horticulture ScienceZhejiang A&F UniversityHangzhouZhejiang 311300China

Glucosinolates(GSLs) are a group of nitrogen-and sulfur-containing secondary metabolites, synthesized primarily in members of the Brassicaceae family, that play an important role in food flavor, plant antimicrobial activity, resistance to insect attack, stress tolerance, and human anti-cancer effects. As a sulfur-containing compound, glutathione has a strong connection with GSLs biosynthesis as a sulfur donor or redox system, and exists in reduced(glutathione;GSH) and oxidized(glutathione disulfide;GSSG) forms. However, the mechanism of GSH regulating GSLs biosynthesis remainds unclear. Hence, the exogenous therapy to pakchoi under normal growth condition and sulfur deficiency condition were conducted in this work to explore the relevant mechanism. The results showed that exogenous application of buthionine sulfoximine, an inhibitor of GSH synthesis, decreased the transcript levels of GSLs synthesis-related genes and transcription factors, as well as sulfur assimilation-related genes under the normal growth condition. Application of exogenous GSH inhibited the expression of GSLs synthesis-and sulfur assimilation-related genes under the normal condition, while the GSLs biosynthesis and the sulfur assimilation pathway were activated by exogenous application of GSH when the content of GSH in vivo of plants decreased owing to sulfur deficiency. Moreover,exogenous application of GSSG increased the transcript levels of GSLs synthesis-and sulfur assimilation-related genes under the normal growth condition and under sulfur deficiency. The present work provides new insights into the molecular mechanisms of GSLs biosynthesis underlying glutathione regulation.

关键词： Pakchoi Glucosinolates Reduced glutathione Oxidized glutathione Sulfur assimilation

Catalytic enantioselective N-silylation of sulfoximine

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Chinese Chemical Letters 2024年第4期35卷 352-356页

作者： Xingfen Huang Jiefeng zhu Chuan He Shenzhen Grubbs Institute and Department of Chemistry Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhen 518055China Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education Hangzhou Normal UniversityHangzhou 311121China

A rhodium/diphosphine-catalyzed asymmetric cross-dehydrogenative coupling between sulfoximines and dihydrosilanes has been achieved. This is the first report on the enantioselective N-silylation of sulfoximines. The protocol gives access to a variety of Si-stereogenic N-silylated sulfoximines in decent yield(up to 99%) with excellent stereoselectivity(up to 99%), featuring high atom economy, and a cleaner manner with H2as the sole byproduct. The obtained bis-Si-stereogenic monohydrosilane product can be further converted into the corresponding chiral polymer with pendant sulfoximine groups.

关键词： N-Silylation of sulfoximine Chiral silylamine Si-stereogenic silanes Si-CADC Asymmetric catalysis

Discovery of strong bulk Dzyaloshinskii-Moriya interaction in composition-uniform centrosymmetric magnetic single layers

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 174-180页

作者： Lijun zhu David Lujan Xiaoqin Li State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China Department of Physics Center for Complex Quantum SystemsUniversity of Texas at AustinAustin 78712USA

Dzyaloshinskii-Moriya interaction(DMI)is the key ingredient of chiral spintronic phenomena and the emerging technologies based on such phenomena.A nonzero DMI usually occurs at magnetic interfaces or within non-centrosymmetric single crystals.Here,we report the observation of a strong unexpected DMI within a centrosymmetric polycrystalline ferromagnet that has neither a crystal inversion symmetry breaking nor a composition gradient.This DMI is a bulk effect,increases with the thickness of the magnetic layer,and is insensitive to the symmetry of the interfaces or the neighboring materials.We observe a total DMI strength that is a factor of>2 greater than the highest interfacial DMI in the literature.This DMI most likely arises from the strong spin-orbit coupling,strong orbital hybrization,and a“hidden”long-range asymmetry in the material.Our discovery of the strong unconventional bulk DMI in centrosymmetric,composition-uniform magnetic single layers provides fundamental building blocks for the emerging field of spintronics and will stimulate the exploitation of unconventional spin-orbit phenomena in a wide range of materials.

关键词： Brillouin light scattering Dzyaloshinskii-Moriya interaction spin wave

An improved bound on accelerated light dark matter

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 105-118页

作者： Liangliang Su Lei Wu Bin zhu Department of Physics and Institute of Theoretical Physics Nanjing Normal UniversityNanjing 210023China School of Physics Yantai UniversityYantai 264005China

Light(sub-GeV)dark matter has gained increasing interest in terms of direct detection.Accelerated dark matter is a promising candidate that can generate detectable nuclear recoil energy within the sub-GeV range.Because of the large kinetic energy,its interactions with the nucleus are predominantly governed by inelastic scattering,including quasi-elastic and deep inelastic scattering.In this work,we calculated the inelastic effects in dark matter-Earth scattering mediated by a vector particle.Our analysis revealed that the impact of inelastic scattering relies on the mediator mass and the kinetic energy spectrum of dark matter.The results exhibited considerable disparity:the upper bounds of the exclusion limit for the spin-independent cross-section between accelerated dark matter and nuclei via a heavy mediator differ by several tens of times when inelastic scattering is considered.

关键词： accelerated dark matter inelastic scattering direct detection experiment

Roles of endophytic fungi in medicinal plant abiotic stress response and TCM quality development

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Chinese Herbal Medicines 2024年第2期16卷 204-213页

作者： Jiahao Zhang Jiemiao Lu Yichun zhu Xiaoxia Shen Bo zhu Luping Qin School of Pharmaceutical Sciences Zhejiang Chinese Medical UniversityHangzhou 310053China Songyang Institute of Zhejiang Chinese Medical University Songyang 323400China

Medicinal plants,as medicinal materials and important drug components,have been used in traditional and folk medicine for ages.However,being sessile organisms,they are seriously affected by extreme environmental conditions and abiotic stresses such as salt,heavy metal,temperature,and water stresses.Medicinal plants usually produce specific secondary metabolites to survive such stresses,and these metabolites can often be used for treating human diseases.Recently,medicinal plants have been found to partner with endophytic fungi to form a long-term,stable,and win-win symbiotic relationship.Endophytic fungi can promote secondary metabolite accumulation in medicinal plants.The close relationship can improve host plant resistance to the abiotic stresses of soil salinity,drought,and extreme temperatures.Their symbiosis also sheds light on plant growth and active compound production.Here,we show that endophytic fungi can improve the host medicinal plant resistance to abiotic stress by regulating active compounds,reducing oxidative stress,and regulating the cell ion balance.We also identify the deficiencies and burning issues of available studies and present promising research topics for the future.This review provides guidance for endophytic fungi research to improve the ability of medicinal plants to resist abiotic stress.It also suggests ideas and methods for active compound accumulation in medicinal plants and medicinal material development during the response to abiotic stress.

关键词： abiotic stress active compounds endophytic fungus medicinal material development medicinal plant

Microfluidic separation of particles by synergistic effect of geometry-induced hydrodynamics and magnetic field

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Chinese Chemical Letters 2024年第2期35卷 380-385页

作者： Du Qiao Hongxia Li Weiping zhu Lili zhu Danyang Zhao Honglin Li Key Laboratory for Precision & Non-traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian 116023China Shanghai Key Laboratory of New Drug Design School of PharmacyEast China University of Science and TechnologyShanghai 200237China Lingang Lab Shanghai 200031China

Microfluidic combined with magnetic field have been demonstrated to be the promising solutions for fast and low-damage particles separation.However,the difficulties in the precise layout of magnets and accurate prediction of particle trajectories lead to under and over separation of target particles.A novel particle separation lab-on-chip(LOC)prototype integrated with microstructures and micropolar arrays is designed and characterized.Meanwhile,a numerical model for the separation of magnetic particles by the synergistic effect of geometry-induced hydrodynamics and magnetic field is constructed.The effect of geometry and magnetic field layout on particle deflection is systematically analyzed to implement accurate prediction of particle trajectories.It is found that the separation efficiency of magnetic particles increased from 50.2%to 91.7%and decreased from 88.6%to 85.7%in the range of depth factors from 15µm to 27µm and width factors from 30µm to 60µm,respectively.In particular,the combined effect of the offset distance of permanent magnets and the distance from the main flow channel exhibits a significant difference from the conventional perception.Finally,the developed LOC prototype was generalized for extension to arbitrary systems.This work provides a new insight and robust method for the microfluidic separation of magnetic particles.

关键词： Microfluidic Particle separation Synergistic effect Hydrodynamics Magnetic field Numerical calculation

Effect of autologous bone marrow stem cells-scaffold transplantation on the ongoing pregnancy rate in intrauterine adhesion women:a randomized,controlled trial

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Science China(Life Sciences) 2024年第1期67卷 113-121页

作者： Hui zhu Taishun Li Peizhen Xu Lijun Ding Xianghong zhu Bin Wang Xiaoqiu Tang Juan Li Pengfeng zhu Huiyan Wang Chenyan Dai Haixiang Sun Jianwu Dai Yali Hu Department of Obstetrics and Gynecology Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing 210008China Department of Biostatistics Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing 210008China Department of Gynecology Changzhou Maternal and Child Health Care HospitalChangzhou Medical CenterNanjing Medical UniversityChangzhou 213004China Clinical Center for Stem Cell Research Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing 210008China Department of Hematology Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing 210008China Institute of Genetics and Developmental Biology Chinese Academy of SciencesBeijing 100190China

Intrauterine adhesion is a major cause of female reproductive disorders.Although we and others uncontrolled pilot studies showed that treatment with autologous bone marrow stem cells made a few patients with severe intrauterine adhesion obtain live birth,no large sample randomized controlled studies on this therapeutic strategy in such patients have been reported so far.To verify if the therapy of autologous bone marrow stem cells-scaffold is superior to traditional treatment in moderate to severe intrauterine adhesion patients in increasing their ongoing pregnancy rate,we conducted this randomized controlled clinical trial.Totally 195 participants with moderate to severe intrauterine adhesion were screened and 152 of them were randomly assigned in a 1:1 ratio to either group with autologous bone marrow stem cells-scaffold plus Foley balloon catheter or group with only Foley balloon catheter(control group)from February 2016 to January 2020.The per-protocol analysis included 140 participants:72 in bone marrow stem cells-scaffold group and 68 in control group.The ongoing pregnancy occurred in 45/72(62.5%)participants in the bone marrow stem cells-scaffold group which was significantly higher than that in the control group(28/68,41.2%)(RR=1.52,95%CI 1.08–2.12,P=0.012).The situation was similar in live birth rate(bone marrow stem cells-scaffold group 56.9%(41/72)vs.control group 38.2%(26/68),RR=1.49,95%CI 1.04–2.14,P=0.027).Compared with control group,participants in bone marrow stem cells-scaffold group showed more menstrual blood volume in the 3rd and 6th cycles and maximal endometrial thickness in the 6th cycle after hysteroscopic adhesiolysis.The incidence of mild placenta accrete was increased in bone marrow stem cells-scaffold group and no severe adverse effects were observed.In conclusion,transplantation of bone marrow stem cells-scaffold into uterine cavities of the participants with moderate to severe intrauterine adhesion increased their ongoing pregnancy and live birth rates,and this therapy was relatively

关键词： intrauterine adhesion Asherman’s syndrome uterine infertility autologous bone marrow stem cells transplantation endometrial regeneration ongoing pregnancy rate